Oil and petroleum products, methods of mass measurement. Determination of the mass of petroleum products GOST oil and petroleum products methods for measuring mass

General provisions.

The determination of the mass of oil and petroleum products is currently determined by several GOSTs:

GOST 26976-86, Oil and petroleum products. Mass measurement methods

GOST R8.595-2002, Mass of oil and petroleum products. General requirements for measurement techniques

GOST 3900-85, Oil and petroleum products. Density measurement methods

According to GOST R8.595-2002, GOST 26976-86, the following is used to measure the mass of the product in pipelines, tanks, and reservoirs:

Direct method of dynamic measurements;

Indirect method of dynamic measurements;

Direct method of static measurements;

Indirect method of static measurements;

Indirect static measurement method based on hydrostatic pressure.

First way– measurement of mass on the flow using mass meters.

Second way– mass is determined on the flow by measuring volume flow and density under the same conditions (temperature, pressure) according to formula 4.1:

m – product mass, kg/hour;

ρ – product density, kg/m3;

V – product volume, m 3 /hour.

Density and volume are allowed to be brought to standard conditions
(t = 15°C, Pg = 0).

Third way– direct weighing of road and railway tanks.

Fourth method - the mass of the product is determined by the results of measurements: density, product level in the container, product temperature, product volume according to the calibration table.

Density and level are measured at the same pressure and temperature. it is allowed to transfer ρ and V to standard conditions and then

m = ρ standard condition. V st.conv.

Fifth method– the mass in containers is determined by measuring the hydrostatic pressure of the liquid column in the container, which is based on the following relationships:

R T.S. – pressure measured by a manometer, Pa;

F is the gravity of the product above the installation location of the pressure sensor or pressure gauge, N;

m – mass, kg;

S – cross-sectional area of ​​the tank at the location where the sensor is installed, m2;

g – 9.81 m/s 2 .

Confidence relative errors of mass measurements using these methods with a confidence probability of 0.95 should not exceed:

0.1% - with the direct method of static measurements;

0.4% - with the indirect method of static measurements and the indirect method based on the hydrostatic principle.

According to GOST 26976-86 for direct and indirect measurement methods with a net mass of oil and petroleum products of 100 tons and above, the error should not exceed ±0.5% and ±0.8% when measuring mass up to 100 tons.

Thus, the later GOST R8.595-2002 tightens the requirements for measuring mass, however, the role of the human factor in measurement is too great, the properties of petroleum products give certain deviations from theoretical dependencies, therefore the spread of data when determining mass exceeds the error established by GOST R8.595-2002 – 0.4%.

As a result, Gosstandart, by resolution No. 157st dated 03/09/2004, introduces changes to GOST R8.595-2002 from 08/01/2004, which are set out in the following wording:

0.4% - with the direct measurement method by weighing uncoupled tanks;

0.5% - the same for trains and uncoupled tanks in motion;

0.5% - with the indirect method of static measurements and when using the hydrostatic principle for masses of 100 tons and above;

0.65% - the same for mass up to 100 tons;

0.25% - with direct and indirect methods of dynamic measurements;

Both of these GOSTs approve methods for assessing the error when measuring mass in various ways.

We will be interested in measuring mass by the indirect method of static measurements, i.e. measurement of mass in tanks, since despite the installation of in-line quantitative metering devices at many enterprises, more than 90% of metering is carried out in tanks and containers.

During acceptance and delivery operations, the mass is determined as the difference in mass before and after the accounting operation. The model of the volume-mass statistical method and the error model of the method for this case are presented in GOST 26976-86.

According to this GOST, the volume-mass model (indirect static measurement method) of the static method is expressed by equation 4.2:

m is the mass obtained as a result of the commodity operation, kg;

m i - mass received before the start of the commodity operation, kg;

m i +1 - mass after commodity operation, kg;

Vi, Vi +1 - volumes of product at the beginning and end of the commodity operation, respectively, m 3;

ρ i, ρ i +1 - density of the product in the tank before and after the commodity operation, respectively, kg/m 3;

α - coefficient linear expansion of the tank wall material, gr -1;

β - coefficient volumetric expansion of the product, g -1;

δ t st = (t v –t gr) – the difference in wall temperatures when determining the volume in a commodity operation and when calibrating the tank, °C;

δ t st = (t ρ –t v) – temperature difference when measuring density and volume, °C.

The method error model is expressed by formula 4.3:

, %, (4.3)

Δρ - relative error of density measurement;

H i, i +1 - product level in the container before and after the commodity operation, m;

ΔН - absolute error of level measurement, m;

ΔК - relative error of tank calibration;

ΔM - relative error of the information processing unit, %;

Relative error of density measurement:

,

Δρ hydrometer – absolute error of the hydrometer, kg/m3;

Δρ min – minimum density of the product in a commodity operation, kg/m3.

Absolute error Δδ t of measuring the temperature difference of the product when measuring density Δt ρ and volume Δt v:

.

It should be noted that GOST 26976-86 also shows models of the volume-mass dynamic method and its errors for determining mass, the same for the hydrostatic method, for measuring the net mass of oil.

GOST R8.595-2002 additionally allows you to determine mass in indirect methods through density and volume reduced to standard conditions (15 °C, P = 0). Therefore, this GOST approves slightly different models for determining their errors.

For example, for the equation of the case considered above, the error is determined by formula 4.4:

A i +1 , B i +1 – the same with notations (i+1);

ΔК i – relative calibration error, %;

ΔН i – relative error of level measurement, %;

K f i – coefficient taking into account the geometric shape of the capacity measure when pouring N i;

Δρ i – relative error of density measurement, %;

ΔT ρ , ΔT V – rel. temperature measurement error when measuring ρ and V, %;

G i – coefficient determined by the formula

,

T Vi , T ρi – product temperatures when measuring volume and density.

If, when assessing the error of any method for determining mass using these dependencies, an error of less than, for example, ± 0.5% for the volumetric-mass method is obtained, then the instruments used and the calibration of tanks meet the measurement accuracy requirements in force for a given period of time.

4.2 Volume-mass static method

(indirect method of static measurements)

The use of the volume-mass static method presupposes the availability of calibration tables for tanks, railway and tank trucks, the ability to determine the level of the product in a calibrated container and its density at a given temperature.

Calibration tables, as mentioned earlier, are carried out by specialized metrological organizations and approved by the head of the territorial body of the State Standard of the Russian Federation. The capacity of the tanks is determined by the manufacturer and then verified by the State Standards Authority of the Russian Federation at least once every 2 years.

The level of the product in tanks is measured either by stationary level gauges, which, together with other measuring instruments used, ensure the accuracy of mass determination in accordance with GOST 26976-86 or GOST R8.595-2002, or manually with a measuring tape with a lot, which must comply with GOST 7502-89. A tape measure with a lot is a steel tape on which divisions are applied at 1 mm intervals; a weight is attached to the tape - a massive steel cylinder with divisions at 1 mm intervals, which provides tension on the tape and measurement of small levels.

The level of oil product in railway tanks is measured manually with a meter rod (TU 112-RSFSR-029-90). A meter rod is a steel ruler with divisions marked every mm.

The volume of product in tank trucks is determined by the filling level indicator installed in the neck of the tank boiler. The level indicator corresponds to its actual capacity. Currently, in almost all enterprises, the volume of product released into a tank truck is determined by the readings of volume meters, the error of which should not exceed ± 0.25%.

Measuring the level with a tape measure with a lot is carried out in the following sequence:

Check the base height (or otherwise stencil height). The result obtained is compared with a known value applied to the tank. If both results differ by more than 0.1% from H bases, then it is necessary to find out the cause and eliminate it;

Lower the measuring tape with the load (lot) carefully without distortion, avoiding any waves on the surface of the liquid; the tape should be in a taut state. Lifting is carried out in the same way to avoid distortion of the wetting line;

The level is measured along the wetting line immediately after the wetted part of the tape appears above the measuring hatch;

The measurement is repeated twice, the difference in readings should not exceed 1 mm;

The level is measured with a meter rod twice on one and the other along the diameter side of the hatch. The meter rod should not fit into the recess at the bottom for bottom drains. The discrepancy in measurements should not exceed 1 mm;

If produced water is present, its level is determined using the same means, but a tape with a water-sensitive paste applied to it is attached to the lot, which changes its color under the influence of water. The height of the tape is of a different color and corresponds to the level of produced water. The same is true for measurements with a meter rod. To determine the actual volume of oil or petroleum product, it is necessary to subtract the volume corresponding to the water level from the volume corresponding to the general filling level.

volumetric - mass static method

in tanks, railway

and automobile tanks

4.2.1. Determination of capacity and graduation

tanks, railway and road tanks

4.2.1.1. Determination of capacity and calibration of steel vertical cylindrical tanks is carried out in accordance with MI 1823-87.

4.2.1.2. Determination of capacity and calibration of reinforced concrete cylindrical tanks is carried out according to RD 50-156-79.

4.2.1.3. Determination of capacity and calibration of horizontal cylindrical tanks with a volume from 3 to 200 cubic meters. m are carried out according to GOST 8.346-79.

4.2.1.4. Railroad and road tanks used as capacity measures during accounting and settlement operations must be calibrated in accordance with the requirements of Instruction 36-55.

4.2.1.5. Graduation tables are revised within the established time limits in accordance with current standards. After each repair associated with a change in capacity, the tank must be re-graded, and after a change in its internal equipment, the calibration table must be revised and approved in the prescribed manner.

Carry out annual corrections of tank bottoms with the preparation of appropriate reports for each tank.

4.2.1.6. Work on calibration of tanks is carried out by specialized metrological organizations (groups) or persons who have been trained to measure the capacity of tanks in the manner established by the State Standard of the Russian Federation, who have received the right to carry out the specified work and registered in the prescribed manner.

Calibration tables for tanks intended for operational control are approved by the head (chief engineer) of the joint-stock company; for tanks intended for accounting and settlement operations, is approved by the head of the territorial body of the State Standard of the Russian Federation.

4.2.2. Determination of the level of petroleum products

and produced water in tanks

and vehicles

4.2.2.1. The level of petroleum product in tanks is measured by stationary level gauges that ensure accurate determination of mass in accordance with GOST 26976-86, as well as manually with a measuring tape with a load (lot) in accordance with GOST 7502-89. The level of petroleum product in railway tanks is measured manually with a metro rod according to TU 112-RSFSR-029-90.

4.2.2.2. The volume of petroleum products in automobile tanks is determined by the filling level indicator installed in the neck of the tanker's boiler at a level corresponding to its actual capacity, or by a given dose according to the readings of the volume meter.

The actual capacity of automobile tanks according to the filling level indicator is established by the manufacturer. The capacity of automobile tanks is verified by the territorial bodies of Gosstandart in accordance with GOST 27352-87 and Instructions 36-55. The frequency of checking the capacity of automobile tanks is at least once every 2 years.

When using a volume meter to measure the volume (dose) of petroleum product, the measurement error should not exceed +/- 0.5% under operating conditions.

4.2.2.3. Measuring the level of petroleum product with a tape measure with a load (lot) is carried out in the following sequence.

4.2.2.3.1. Check the base height (height stencil) as the vertical distance between the bottom of the tank at the point of contact of the tape measure and the measuring hatch bar. The obtained result is compared with the known (certified) value of the base height marked on the tank.

If the base (certificate) height (BN) differs from the obtained result by more than 0.1% BN, it is necessary to identify the reason for the change in the base height and eliminate it.

4.2.2.3.2. The measuring tape of the tape measure with the lot should be lowered slowly until the lot touches the bottom, preventing the lot from deviating from the vertical position and hitting the bottom of the tank, without touching the internal equipment and maintaining a calm state of the surface of the oil product, avoiding waves. The tape measure must be kept taut at all times, and the point where the lot touches the bottom of the tank must be horizontal and rigid.

4.2.2.3.3. Raise the tape measure up strictly vertically, without allowing it to move to the side, in order to avoid distortion of the wetting line on the measuring tape.

4.2.2.3.4. The tape measure is measured down to 1 mm immediately after the wetted part of the tape measure appears above the measuring hatch.

4.2.2.3.5. The tape measure must be wiped dry with a soft cloth before and after measurements.

4.2.2.4. The level of petroleum product in each tank or railway tank is measured twice. If the measurement results differ by 1 mm, then their average value is taken as the result of level measurement; if the resulting measurement discrepancy is more than 1 mm, then the measurements are repeated twice more and the average of the three closest measurements is taken.

4.2.2.5. Measuring the oil product level with a metro rod is carried out similarly to the requirements of paragraphs 4.2.2.3 and 4.2.2.4.

4.2.2.6. Determination of the level of produced water in tanks and transport containers.

The level of produced water in tanks and transport containers is determined using water-sensitive tape or paste.

To determine the level of produced water, a water-sensitive tape is tensioned and attached to the surface of the lot or to the lower end of the metro rod on two opposite sides.

Water-sensitive paste is applied in a thin layer (0.2 - 0.3 mm) to the surface of the lot or the lower end of the metro rod in strips on two opposite sides.

When determining the level of produced water, a tape measure with a lot or a metro rod with a water-sensitive paste or with an attached water-sensitive tape should be kept motionless in a tank or container for 2 - 3 minutes, when the water-sensitive layer is completely dissolved and the boundary between the layers of water and oil product is sharply highlighted.

Determination of the level of produced water in tanks and vehicles should be carried out in accordance with paragraphs. 4.2.2.4 and 4.2.2.5.

Measurement of the produced water level should be repeated if the level on the tape or paste is not clearly indicated, by an oblique line, or at unequal heights on both sides, which indicates that the lot is in an inclined position when taking measurements.

The blurred edge is a consequence of the absence of a sharp interface between water and oil product and indicates the presence of a water-emulsion layer. In this case, it is necessary to repeat the measurement after settling and separation of the emulsion.

Having determined the level of produced water using a water-sensitive tape or paste, the volume of produced water is found using the calibration table of the tank or transport container.

To determine the actual volume of petroleum product, it is necessary to subtract the volume of produced water from the volume corresponding to the filling level of the container.

4.2.2.7. The levels of petroleum product in railway tanks, in the absence of meters or metering units, are measured with a metro rod through the neck of the tank boiler at 2 opposite points of the neck along the axis of the tank, making sure that the metro rod falls vertically onto the lower generatrix of the tank boiler and does not fall into the recess for the lower drain devices .

Discrepancies in measurements should not exceed 1 mm, otherwise the measurements must be repeated.

If the volume of petroleum products supplied is determined by commercial meters, then their level in the tanks is not measured.

When accepting petroleum products from sea and river tankers and oil barges, require the separation of produced water on the vessel.

Appendix No. 4

to the Rules for the transportation of liquid cargo in bulk in tank cars
and bunker-type cars for transportation of oil bitumen

The procedure for determining the mass of oil and petroleum products in tank cars by calculation method

This appendix provides the procedure for determining the mass of oil and petroleum products in tank cars using the volume-mass static method, which includes sampling to determine the temperature and density of the cargo, measuring the loading height and calculating the mass of the cargo in the tank car.

1. The quantity of products upon shipment and acceptance is determined by the volume-mass static method, that is, by measuring the height of loading of the petroleum product in the tank with a meter rod, determining the volume using calibration tables, measuring the density and subsequent calculation of the mass of the petroleum product.

It is allowed to determine the mass of cargo in a railway tank by weighing the tare mass and gross mass on a carriage scale and then determining the net mass.

2. The procedure for sampling, determining the average volume temperature and density of the oil product poured into a railway tank.

2.1. To determine the average volumetric temperature and density of the cargo, samples from tank cars are taken in accordance with GOST 2517 "Oil and petroleum products. Sampling methods." A point sample from the tank car is taken with a portable sampler from a level located at a height of 0.33 of the internal diameter of the tank, counting from the bottom generatrix of the boiler. The sampling scheme is shown in Fig. 1. The levels of point sampling from tank cars located in the operating fleet of the network are given in Table. 1.

Rice. 1 Scheme for sampling petroleum products from railway tanks

Table 1

Levels of sampling of petroleum products from railway tanks (according to GOST 2517)

State system for ensuring the uniformity of measurements WEIGHT OF OIL AND PETROLEUM PRODUCTS General requirements for measurement techniques Moscow IPK Publishing house of standards 2005 Preface The tasks, basic principles and rules for carrying out work on state standardization in the Russian Federation are established by GOST R 1.0-92 “State standardization system of the Russian Federation. Basic provisions" and GOST R 1.2-92 "State standardization system of the Russian Federation. The procedure for developing state standards" Standard information 1 DEVELOPED by the Federal State Unitary Enterprise All-Russian Research Institute of Flow Measurement State Scientific Metrological Center (FSUE VNIIR-GNMC) 2 INTRODUCED by the Department of Metrology and State Supervision 3 APPROVED AND ENTERED INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated December 7, 2004 No. 99-st 4 This standard was developed taking into account the requirements of international standards: ISO 91-1-92, ISO 91-2-91, ASTM D 1250-80, API 2540-80 5 INSTEAD GOST R 8.595-2002 GOST R 8.595-2004 NATIONAL STANDARD OF THE RUSSIAN FEDERATION State system for ensuring the uniformity of measurements WEIGHT OF OIL AND PETROLEUM PRODUCTS General requirements for measurement techniques State system for ensuring the uniformity of measurements. Mass of petroleum and petroleum products. General requirements for procedures of measurements Date of introduction - 2005-11-01 1 area of ​​use This standard applies to methods for performing measurements (hereinafter referred to as MVI) of the mass of commercial oil and petroleum products (hereinafter referred to as the product) in the areas of state metrological control and supervision, based on: Direct methods of dynamic and static measurements; Indirect methods of dynamic and static measurements; Indirect method based on the hydrostatic principle. This standard establishes the basic requirements for the MVI of product mass, determined by the peculiarities of product mass measurements. This standard is required for use when developing MVIs for the mass of a product transported through pipelines in capacity measures and total capacity measures. This standard is used in conjunction with GOST R 8.563. 2 Normative references 3 Definitions The following terms with corresponding definitions are used in this standard: 3.1 measurement technique (MVI) of product mass: A set of operations and rules, the implementation of which ensures the obtaining of product mass measurement results with a specified error (uncertainty). 3.2 product mass measurement error: Generalized error of all measurement results of product mass with strict fulfillment of all MVI requirements. 3.3 measure of capacity: A product volume measuring device that has a verification certificate and an approved calibration table. 3.4 measure of total capacity: A product volume measuring device that has a verification certificate and is equipped with a filling level indicator (tank trucks, tank trailers, tank semi-trailers). 3.5 direct method of dynamic measurements of product mass: A method based on direct measurements of product mass using mass meters in pipelines. 3.6 direct method of static measurements of product mass: A method based on direct measurements of the mass of a product by static weighing or weighing in railway or road tanks and trains as they move on scales. 3.7 indirect method of dynamic measurements of product mass: A method based on measurements of the density and volume of a product in pipelines. 3.8 indirect method of static measurements of product mass: A method based on measurements of the density and volume of a product in terms of capacity (full capacity measures). 3.9 indirect method based on the hydrostatic principle: A method based on measurements of hydrostatic pressure and product level in capacity measures. 3.10 accounting transaction: An operation carried out by the supplier and the consumer or the delivery and receiving parties, which consists in determining the mass of the product for subsequent calculations, during inventory and arbitration. 3.11 standard conditions: Conditions corresponding to a product temperature of 15 °C or 20 °C and a gauge pressure of zero. 3.12 commercial oil (petroleum): Oil prepared for delivery to the consumer in accordance with the requirements of GOST R 51858. 3.13 gross weight of commercial oil: Mass of commercial oil, the quality indicators of which comply with the requirements of GOST R 51858. 3.14 ballast mass: Total mass of water, salts and mechanical impurities in commercial oil. 3.15 net mass of commercial oil: Difference between the gross mass of commercial oil and the mass of ballast. 4 Measurement methods implemented in the MVI of product mass 4.1 To measure the mass of a product transported or pumped through pipelines, use: Direct method of dynamic measurements; Indirect method of dynamic measurements. To measure the mass of a product in measures of capacity and measures of total capacity, use: Direct method of static measurements; Indirect method of static measurements; Indirect method based on the hydrostatic principle. 4.2 In the direct method of dynamic measurements, the mass of the product is measured using a mass meter and the result of the mass measurements is obtained directly. 4.3 With the indirect method of dynamic measurements, the mass of the product is determined from the results of the following measurements in the pipeline: a) density using in-line density converters (hereinafter referred to as density converters), pressure and temperature. When the working one is turned off and there is no backup density converter, the density of the product is determined using a hydrometer in the laboratory in accordance with GOST 3900, GOST R 51069 or a laboratory density meter in a combined sample made up of point samples taken in accordance with GOST 2517. The coefficients of volumetric expansion and compressibility of the product are determined in accordance with MI 2632 or taken for oil according to MI 2153, for petroleum products according to MI 2823; b) product volume using flow, pressure and temperature transducers or liquid meters. The results of measuring the density and volume of a product lead to standard conditions, or the result of measuring the density of a product leads to the conditions for measuring its volume. 4.4 With the direct method of static measurements, the mass of the product is determined by the results of weighing on railway and automobile scales in accordance with GOST 29329 or GOST 30414 of railway and automobile tanks with and without the product. 4.5 With the indirect method of static measurements, the mass of the product is determined based on the measurement results: a) in terms of capacity: Product level - with a stationary level gauge or other means of measuring liquid level; Product density - with a portable or stationary density measuring instrument or a hydrometer in accordance with GOST 3900, GOST R 51069 or a laboratory density meter in a combined sample composed of point samples selected in accordance with GOST 2517; Product temperatures - with a thermometer in spot samples or using a portable or stationary temperature transducer; Product volume - according to the calibration table of capacity measures using the result of product level measurements; b) in full capacity measures: Product density - with a portable density measuring device or a hydrometer in the laboratory in accordance with GOST 3900, GOST R 51069 or a laboratory density meter in a spot sample of the product taken in accordance with GOST 2517; Product temperature - with a portable temperature converter or thermometer in a spot sample of the product, selected in accordance with GOST 2517; The volume of the product, taken equal to the actual capacity of the measure, the value of which is printed on the marking plate and indicated in the verification certificate according to GOST R 8.569, taking into account changes in the level of the product relative to the level indicator. The results of measurements of the density and volume of a product lead to standard conditions for a temperature of 15 ° C or 20 ° C, or the result of measurements of the density of a product leads to the conditions of measurement of its volume in measures of capacity and measures of total capacity. The coefficient of volumetric expansion of the product is determined in accordance with MI 2632 or accepted for oil according to MI 2153, for petroleum products according to MI 2823. 4.6 With the indirect method based on the hydrostatic principle, the mass of the product in capacity measures is determined from the measurement results: Hydrostatic pressure of the product column - with a stationary hydrostatic pressure meter; Product level - with a portable or other level measuring device. 4.7 The net mass of commercial oil is determined as the difference between the gross mass of commercial oil and the mass of ballast. Ballast mass is defined as the total mass of water, salts and mechanical impurities in commercial oil. To do this, determine the mass fractions of water, mechanical impurities and chloride salts in commercial oil and calculate their mass. 5 Requirements for MVI of product mass 5.1 Errors in product mass measurements 5.1.1 The limits of permissible relative error in measuring the gross mass of commercial oil and the mass of oil products should not exceed: 0.40% - with the direct method of static measurements by weighing uncoupled tanks on scales; 0.50% - with the direct method of static measurements by weighing moving uncoupled tanks and trains from them on scales; 0.25% - with direct and indirect methods of dynamic measurements; 0.50% - with the indirect method of static measurements and the indirect method of measurement based on the hydrostatic principle, product mass of 120 tons or more; 0.65% - with the indirect static measurement method and the indirect measurement method based on the hydrostatic principle, product weight up to 120 tons. 5.1.2 The limits of permissible relative error in measuring the net mass of commercial oil should not exceed: 0.50% - with the direct method of static measurements by weighing uncoupled tanks on scales; 0.60% - with the direct method of static measurements by weighing moving uncoupled tanks and trains from them on scales; 0.35% - with direct and indirect methods of dynamic measurements; 0.60% - with the indirect static measurement method and the indirect measurement method based on the hydrostatic principle, from 120 tons or more; 0.75% - with the indirect static measurement method and the indirect measurement method based on the hydrostatic principle, up to 120 tons. 5.2 Requirements for documents for MVI of product mass 5.2.1 Depending on the complexity and scope of application of the MVI, the product masses are presented in the form: Section or part of a document (standard, technical specifications, design or technological document, etc.). 5.2.2 Development, standardization and implementation of documents on the MVI of product mass - in accordance with GOST R 8.563, GOST R 1.2, GOST R 1.5, GOST R 1.12, R 50.1.039, MI 2525, MI 2561 and this standard. 5.2.3 MVI of product masses are subject to certification according to GOST R 8.563. 5.2.4 Documents on the MVI of the mass of the product are subject to metrological examination in accordance with GOST R 8.563 and GOST R 1.11. 5.2.5 Documents on the MVI of the mass of the product intended for use in the field of defense and security of the Russian Federation are subject to metrological examination at the 32nd State Research and Testing Institute of the Ministry of Defense of the Russian Federation (hereinafter referred to as the 32nd State Scientific Research Institute of the Ministry of Defense of the Russian Federation). 5.2.6 Algorithms and programs for processing measurement results provided for in the document on the MVI of product mass must undergo metrological certification according to MI 2174 (in the field of defense and security of the Russian Federation - in the 32nd State Scientific Research Institute of the Ministry of Defense of the Russian Federation). 5.3 Estimation of product mass measurement error 5.3.1 The error in mass measurements is assessed using the following methods: a) assessment of the error characteristics of the measurement result of the mass of the product, adopted in Russian ND in the field of ensuring the uniformity of measurements; b) calculating the measurement uncertainty of the mass of the product according to RMG43; c) calculation of accuracy and precision according to GOST R ISO 5725-1 - GOST R ISO 5725-6 for product quality indicators used to calculate its mass. 5.3.2 Requirements for assessing the error characteristics of product mass measurements 5.3.2.1 The measurement error characteristics of the mass of the product are assessed based on an analysis of the sources and components of the measurement error. 5.3.2.2 To reduce the systematic component of the error from the influence of temperature, pressure and other influencing quantities on the measurement results, corrections are introduced. 5.3.2.3 Estimation of the measurement error of product mass using direct methods of measuring quantities is carried out according to GOST 8.207 and MI 1552. 5.3.2.4 Estimation of the measurement error of product mass using the indirect measurement method is carried out according to MI 2083. 5.3.2.5 Forms of presentation and methods of rounding measurement results must comply with MI 1317. 5.4 Measuring instruments and auxiliary devices selected for MVI of product mass 5.4.1 Measuring instruments and auxiliary devices (including computer equipment) are selected when designing a product mass measuring system depending on the accepted methods for measuring quantities, the measurement results of which determine the mass of the product, and the optimal costs of measurements, including the costs of metrological services measuring instruments, subject to compliance with the requirements for MVI, including the measurement error standards for the gross mass of commercial oil and the mass of petroleum product specified in , and the net mass of commercial oil specified in . 5.4.2 Rational methods and measuring instruments and auxiliary devices are selected in accordance with MI 1967. 5.4.3 The document on the MVI contains a list of measuring instruments and auxiliary devices, their designations, types, standardized metrological characteristics (accuracy class, permissible error limit, measurement range, etc.) and the designation of the ND regulating technical requirements and (or) metrological and the main technical characteristics of these measuring instruments and auxiliary devices, and also indicate the possibility of using measuring instruments and auxiliary devices not listed in the list, but satisfying the requirements established in the MVI. 5.4.4 The MVI of the mass of the product must indicate measuring instruments, the types of which are approved according to PR 50.2.009 and included in the State Register of Measuring Instruments. 5.5 Operator qualifications and safety requirements 5.5.1 Persons who have reached the age of 18, have an operator qualification of at least 4th category, have completed training courses, passed a safety exam and have studied the operating instructions for the measuring instruments and auxiliary devices used and the document on MVI by . Persons involved in performing measurements must: Complete training and safety instructions in accordance with GOST 12.0.004; Comply with safety and fire safety regulations established for the facility at which measurements are being taken; Perform measurements in special clothing and shoes in accordance with GOST 12.4.137, GOST 27574, GOST 27575; Periodically monitor the content of harmful substances in the air of the working area, which should not exceed the maximum permissible concentrations established in GOST 12.1.005. 5.5.2 Measuring instruments and auxiliary devices used when performing measurements must be manufactured in an explosion-proof design that corresponds to the class of an explosive zone according to GOST R 51330.0, comply with the requirements of GOST R 51330.9 and have a certificate of explosion protection and permission from the Gosgortekhnadzor of Russia according to the Rules. 5.6 Requirements for measurement conditions 5.6.1 The document on the MVI of the mass of the product must contain nominal values ​​and (or) ranges of values ​​that affect the error of values, and it must be established: The number of measurements (observations) of quantities carried out at each measurement point, for example the number of measurements of the product level in capacity measures; Waiting time before recording the readings of measuring instruments: level and temperature of the product in capacity measures, if these values ​​are not indicated in the RD for them, etc. 5.7 Requirements for processing product mass measurement results 5.7.1 According to MVI, based on the indirect method of dynamic measurements, the density and volume of the product are measured, and the results of these measurements lead to standard conditions or the results of measurements of the density of the product lead to the conditions for measuring its volume. 5.7.1.1 Product mass, kg, when measuring the volume of the product, carried out using a flow transducer or liquid meter, and its density, determined using a density transducer, and subsequent reduction of the measurement results of the volume and density of the product to standard conditions, is calculated using the formula where is the density and volume of the product, reduced to standard conditions. Note - The designation “D” corresponds to the term “dynamic”. The density of the product, reduced to standard conditions at a temperature of 15 °C, , kg/m 3, is calculated using the formula: (2) where is the density of the product, measured at the temperature and pressure of the product in a density converter, kg/m 3 ; A correction factor that takes into account the effect of temperature on the volume of the product, determined for the temperature of the product in the density converter, calculated according to API 2540; A correction factor that takes into account the effect of pressure on product volume, determined for the product pressure in the density converter, calculated according to API 2540. The density of the product, reduced to standard conditions at a temperature of 20 °C, , kg/m 3, is calculated using the formula where is the coefficient of volumetric expansion of the product, calculated according to MI 2632 or MI 2823 for petroleum products. The volume of product reduced to a temperature of 15 °C, m 3, is calculated using the formula (4) where is the volume of the product measured at the temperature and pressure of the product in the flow converter or liquid meter, ml; A correction factor that takes into account the effect of temperature on product volume, determined for the temperature of the product in the flow converter or liquid meter, calculated according to API 2540; A correction factor that takes into account the effect of pressure on product volume, determined for the pressure in the flow transmitter or liquid meter, calculated according to API 2540. Product volume, m3, reduced to a temperature of 20 °C, is calculated using the formula 5.7.1.2 Product mass, kg, when measuring the volume of the product, carried out using a flow transducer or liquid meter, and its density, determined using a hydrometer or laboratory density meter in the laboratory in a combined sample, and subsequent reduction of the measurement results of the volume and density of the product to standard ones conditions are calculated using the formula where is the volume of product reduced to standard conditions, m 3 ; Product density normalized to standard temperature, kg/m3. The value, m 3, is determined by formula (4) or (5). where is the density of the product measured using a hydrometer in laboratory conditions (temperature T r and excess pressure equal to zero), taking into account the systematic error of the method according to MI 2153 or using a laboratory density meter, kg/m 3 ; Correction factor taking into account the effect of temperature on product volume, calculated according to API 2540; TO where is the coefficient of volumetric expansion of the product, calculated using MI 2632. It is allowed that the density of the product, measured by a hydrometer, be reduced to density at a standard temperature of 15 ° C or 20 ° C according to tables ASTM D 1250, ISO 91-1, ISO 91-2 or MI 2153 for oil and according to MI 2842, MI 2823 for petroleum products. 5.7.1.3 The mass of the product, kg, when measuring the volume of the product, carried out using a flow transducer or liquid meter, and its density, determined using an in-line density transducer, and subsequent reduction of the product density measurement results to the conditions for measuring its volume, can be calculated using the formula where is the volume of the product measured at the temperature and pressure of the product in the flow converter or liquid meter, m 3 ; Product density, measured at product temperature and pressure in a density converter, kg/m 3 ; b Product temperature in the density converter, °C; Temperature of the product in the flow converter or liquid meter, °C; g - product compressibility coefficient, the values ​​of which are determined by MI 2632 or according to MI 2153 for oil and according to MI 2823 for petroleum products; Excess pressure of the product in the density converter, MPa; Excessive pressure of the product in the flow converter or liquid meter, MPa. 5.7.1.4 Product mass, kg, when measuring the volume of the product, carried out using a flow transducer or liquid meter, and density determined using a hydrometer according to GOST 3900, GOST R 51069 in a combined sample or using a laboratory density meter, and subsequent presentation of the measurement results the density of the product to the conditions for measuring its volume can be calculated using the formula: b - coefficient of volumetric expansion of the product, the values ​​of which are determined according to MI 2632 or MI 2153 for oil and according to MI 2823 for petroleum products; g - product compressibility coefficient, the values ​​of which are determined by MI 2632 or by 2153 for oil and by MI 2823 for petroleum products; RV- excess pressure of the product when measuring its volume, MPa; TO- correction factor for thermal expansion of glass for hydrometers, calculated according to MI 2153. In the case of density measurements using a laboratory density meter, it is taken equal to unity. 5.7.1.5 Formulas (9), (10) are used when the temperature difference when measuring the density and volume of the product is no more than 15 °C. If the temperature difference when measuring the density and volume of the product is more than 15 °C, calculations are carried out according to. 5.7.2 According to MVI, based on the indirect method of static measurements, the volume and density of the product are measured in measures of capacity or measures of total capacity and the results of these measurements lead to standard conditions or the results of measurements of the density of the product lead to the conditions for measuring its volume. 5.7.2.1 The mass of the product, kg, when measuring the volume of the product in measures of capacity and measures of the total capacity and density of the product using a density converter or in the laboratory in a combined or spot sample and subsequent reduction of the measurement results of the volume and density of the product to the standard temperature condition is calculated using formula: (11) where is the density and volume of the product, reduced to standard temperature conditions. Note - The designation “c” corresponds to the term “static”. The density of the product, normalized to a temperature of 15 °C, kg/m 3, is calculated using the formula where is the density of the product, measured using a hydrometer in the laboratory or using a density converter, kg/m 3 ; A correction factor that takes into account the effect of temperature on product volume, determined for the product temperature in the laboratory or in a density converter, calculated according to API 2540; TO- correction factor for thermal expansion of glass for hydrometers, calculated according to MI 2153. In the case of density measurements using a density converter, it is taken equal to unity. The density of the product, normalized to a temperature of 20 °C, kg/m3, is calculated using the formula The volume of the product, reduced to a temperature of 15 °C, m 3, is calculated using the formula: (14) where is the volume of the product in terms of capacity at the measured level N, determined according to the calibration table of a measure of capacity compiled at a temperature of 20 ° C according to GOST 8.346, GOST 8.570, MI 2543, MI 1124, RD 50-156, MI 2579, MI 1001, or to the extent of full capacity at the product level corresponding to the level indicator in accordance with GOST R 8.569, taking into account changes in the level of the product relative to the level indicator, m 3. The data in the calibration tables correspond to the wall temperature of the capacity measures equal to 20 °C; a ST- temperature coefficient of linear expansion of the wall material of the capacity measure, the value of which is taken equal to 12.5 × 10 -6 1/°С for steel and 10 × 10 -6 1/°С for concrete; a S- temperature coefficient of linear expansion of the material of the product level measuring device (for example, a measuring tape with a weight, a metro rod, a float-type level gauge, etc.). Its values ​​are taken equal to: for stainless steel - 12.5 × 10 -6 1/°С; for aluminum - 23 × 10 -6 1/°С. If necessary, when using level gauges of other types, temperature corrections are introduced to the measured product level, and the value of the coefficient a S taken equal to zero; T ST- temperature of the wall of the capacity measure, taken equal to the temperature of the product in the capacity measure, °C; Correction factor taking into account the effect of temperature on the volume of the product, defined for the temperature of the product at capacity or at full capacity, calculated according to API 2540. The volume of the product, normalized to a temperature of 20 °C, m 3, is calculated using the formula: (15) 5.7.2.2 The density of the product during accounting operations can be reduced to density at a standard temperature of 15 ° C or 20 ° C according to ASTM 1250, ISO 91-1, ISO 91-2 or MI 2153 for oil and according to MI 2842 or MI 2823 for petroleum products . 5.7.2.3 When carrying out accounting operations, the density of oil at a standard temperature of 20 °C can be reduced to the density of oil at a standard temperature of 15 °C and vice versa according to GOST R 8.599. 5.7.2.4 The mass of the product, kg, when reducing the density of the product measured in the laboratory to the conditions for measuring the volume of the product in a capacity measure or a full capacity measure, can be calculated using the formula: (16) where is the density of the product, measured in the laboratory at temperature, kg/m3; b - coefficient of volumetric expansion of the product, the values ​​of which are determined by MI 2632 or for oil - according to MI 2153, petroleum products - MI 2823. 5.7.2.5 Formula (16) can be applied at a temperature difference and T ST no more than 15 °C. 5.7.3 According to MVI, based on the indirect method using the hydrostatic principle, the mass of the product, kg, when measuring the hydrostatic pressure of the product column in terms of capacity is calculated using the formula (17) Where R- hydrostatic pressure of the product column, Pa; S cp- average cross-sectional area of ​​the filled part of the capacity measure, m 2 ; g- gravity acceleration, m/s 2. 5.7.3.1 Average area S cp, m 2, is calculated using the formula: (18) Where V 20 - product volume to the extent of capacity at the measured level N, determined from the calibration table of the capacity measure, m 3 ; a ST- temperature coefficient of linear expansion of the wall of the capacity measure, the value of which is taken equal to 12.5 × 10 -6 1/°С; T ST- temperature of the wall of the capacity measure, taken equal to the temperature of the product in the capacity measure, °C. 5.7.4 Product weight T 0, kg, taken into the capacity measure or released from it, is determined as the absolute value of the difference in the mass of the product according to the formula: T 0 = ½ t i - Ti +1 ½ (19) Where t i, t i+1 - product masses calculated using the formula () or () at the beginning and end of the operation, respectively. 5.7.5 Net weight of marketable oil tn, kg, calculated by the formula tn = T – t b. (20) Where T- gross mass of commercial oil, measured by one of the methods in section , kg; t b- ballast mass, kg, calculated by the formula (21) where is the mass fraction of water in commercial oil, %; Mass fraction of chloride salts in commercial oil, %; Mass fraction of mechanical impurities in commercial oil, %. 5.7.5.1 The mass fraction of water in commercial oil is determined according to GOST 2477. The mass fraction of water in commercial oil can be measured using an in-line moisture meter. 5.7.5.2 The mass fraction of chloride salts in commercial oil is determined according to GOST 21534. The mass fraction of chloride salts in commercial oil can be measured using an in-line salinity meter. 5.7.5.3 The mass fraction of mechanical impurities in commercial oil is determined according to GOST 6370. The mass fraction of mechanical impurities in commercial oil can be measured using an in-line analyzer. 5.8 Form for presenting the results of estimating the measurement error of product mass 5.8.1 In the direct method of dynamic measurements, the error should be considered the error in measuring the mass of the product using a mass meter. 5.8.2 With the direct method of static measurements, the error should be considered the error in measuring the mass of the product using scales. The error in measuring the mass of a product using scales is assessed according to MI 1953. 5.8.3 Limits of permissible relative error in measuring the mass of the product using the indirect method of dynamic measurements d m D, %, calculated by the formula (22) Where d V- relative measurement error of product volume, %. The relative error of the product volume measuring instrument is perceived as negligible if the sum of the remaining components of the product volume measurement error is insignificant in accordance with GOST 8.009; d r DT r , DT V- absolute errors in measuring the temperature of the product when measuring its density and volume, respectively, °C; b - coefficient of volumetric expansion of the product, 1/°С (Appendix); d N- limit of permissible relative error of an information processing device or measuring and computing complex (from the type approval certificate or verification certificate), %; G- coefficient calculated by the formula: (23) Where T V, T r - temperature of the product when measuring its volume and density, °C. 5.8.4 The limits of the permissible relative error in measuring the mass of the product using the indirect method of dynamic measurements and subsequent reduction of the density of the product to the conditions for measuring its volume by or , %, are calculated using the formula: (24) Where d V P- relative measurement error of product volume, %; d r P- relative error of product density measurements, %; d T V r - component of the relative error in measuring the mass of the product due to the absolute errors in temperature measurements , , %, calculated by the formula: (25) Where DT r , DT V- absolute errors of temperature measurements, °C. 5.8.5 The limits of permissible relative error in measuring the mass of the product using the indirect method of static measurements, %, are calculated using the formulas: V 20 - volume of product per 1 mm of filling height of the capacity measure at the measured filling level, m 3 /mm; V 20 - product volume in terms of capacity at the measured filling level. Values DV 20 , V 20 determine the capacity measures at the measured filling level using the calibration table. Meaning K f for vertical cylindrical tanks, liquid tankers of rectangular and cylindrical shapes is taken equal to unity. 5.8.6 The limits of permissible relative error in measuring the mass of the product using the indirect method based on the hydrostatic principle, %, are calculated using the formula: (29) Where d P, d K i+1 - relative errors in compiling the calibration table at the measured filling levels of the capacity measure Ni, Ni+1 respectively, %; K fi, K fi+1 - coefficients taking into account the geometric shape of the capacity measure at the measured filling levels of the capacity measure Ni, Ni+1 accordingly; DT r , DT V- absolute errors in product temperature measurements T r , T V respectively, °C; b) for the indirect method based on the hydrostatic principle (31) Where 31), must not exceed the values ​​​​set in. 5.8.10 The relative error limits for measuring the net mass of commercial oil are calculated using the formula: (32) Where DW M.V- absolute measurement error of the mass fraction of water in commercial oil, %; DW M.P- absolute measurement error of the mass fraction of mechanical impurities in commercial oil, %; DW M.S- absolute measurement error of the mass fraction of chloride salts in commercial oil, %. Meaning d T* when using indirect methods of measuring the mass of the product is calculated using the formula: Where d T- limit of permissible relative error in measuring the gross mass of oil or mass of petroleum product by indirect methods, %. When using direct methods for measuring product mass, the value d T* is taken equal to the relative error of measuring the mass of the product using a mass meter or scale. Absolute errors in measurements of mass fractions of water, mechanical impurities and chloride salts in commercial oil are determined based on the results of assessing intermediate indicators of precision and accuracy of standard measurement methods in each laboratory conducting analyzes during accounting operations, in accordance with GOST R ISO 5725-1 - GOST R ISO 5725-6.
690,0-699,9	0,00130	850,0-859,9	0,00081
700,0-709,9	0,00126	860,0-869,9	0,00079
710,0-719,9	0,00123	870,0-879,9	0,00076
720,0-729,9	0,00119	880,0-889,9	0,00074
730,0-739,9	0,00116	890,0-899,9	0,00072
740,0-749,9	0,00113	900,0-909,9	0,00070
750,0-759,9	0,00109	910,0-919,9	0,00067
760,0-769,9	0,00106	920,0-929,9	0,00065
770,0-779,9	0,00103	930,0-939,9	0,00063
780,0-789,9	0,00100	940,0-949,9	0,00061
790,0-799,9	0,00097	950,0-959,9	0,00059
800,0-809,9	0,00094	960,0-969,9	0,00057
810,0-819,9	0,00092	970,0-979,9	0,00055
820,0-829,9	0,00089 ). MI 2525-99 State system for ensuring the uniformity of measurements. Recommendations on metrology of state scientific metrological centers of the State Standard of Russia. Development order. M.: VNIIMS, 1999 MI 2561-99 State system for ensuring the uniformity of measurements. The procedure for developing lists of organizations to which draft regulatory documents of the SSI should be sent for review. M.: VNIIMS, 1999 MI 2174-91 State system for ensuring the uniformity of measurements. Certification of algorithms and programs for data processing during measurements. Basic provisions. P.: VNIIM, 1991 RMG 43-2001 State system for ensuring the uniformity of measurements. Application of the “Guide to the Expression of Measurement Uncertainty”. M.: IPK Standards Publishing House, 2001 MI 1552-86 State system for ensuring the uniformity of measurements. Single direct measurements. Estimation of errors of measurement results. P.: VNIIM, 1991 MI 2083-90 State system for ensuring the uniformity of measurements. Measurements are indirect. Determination of measurement results and estimation of their errors. P.: VNIIM, 1990 Keywords: mass, gross mass of commercial oil, ballast mass, net mass of commercial oil, product, measurement procedure, volume, capacity, reservoir, tank, level gauge, meter, error, level, graduation, verification, temperature, density, pressure, compressibility

Tank calibration type	14	15	16	17	18	24	25	25a	31	53, 53a	61	62*	62	63	66	67	69	70	71	72
	209	209	210	210	208	210	218,5	220,5	218,5	218,5	217,5	212,5*	217,5	243	217,5	218,5	232,5	232,5	225,5	231

Tank calibration type	79	80	81	82	83	85	86	87	88	89	90	91	92	93	94	95	96	99	100	101
Sampling levels, counting from the top edge of the manhole neck (cap), cm	205	210	204	215	212	204	204	204	204	207	217,5	206	217,5	217,5	204	204	204	204	208	217,5

Note:* - For tanks with a cap height of 85 mm.

2.2. Portable samplers (Fig. 2) for sampling petroleum products must have lids or plugs that ensure their tightness and can be easily opened at a given level. The mass of the portable sampler must be sufficient to ensure its immersion in the oil product

2.3. Before each sampling, it is necessary to inspect the sampler to identify possible defects in the body, plugs, covers, gaskets that violate the tightness of the sampler, as well as the presence of foreign liquids and objects. To avoid contamination, portable samplers are carried in covers, cases or other packaging.

Rice. 2 Portable sampler

2.4. The closed sampler is lowered to a given level according to table. 1 so that the hole through which it is filled is at the level indicated in Fig. 1. When measuring the temperature and density of an oil product, keep the sampler at a given level for at least 5 minutes before filling it, open the lid or plug, fill the sampler and lift it.

2.5. The bottle with the selected sample of the easily evaporating petroleum product is removed from the frame, hermetically sealed, and a dry, clean bottle is inserted to take the next sample.

2.6. Spot samples from several tanks with petroleum products of the same brand are taken from every fourth tank, but not less than from two tanks. When discharging petroleum products of different brands or petroleum products of the same brand, but having different quality passports (certificates) of the consignor, samples are taken and analyzed separately. Spot samples of petroleum products intended for export or long-term storage are taken from each tank.

2.7. When performing sampling work, safety and fire safety rules when handling petroleum products must be observed.

Portable samplers must be made of a material that does not produce sparks upon impact (aluminum, bronze, brass, etc.). In order to prevent inhalation of harmful petroleum product vapors, it is necessary to stand with your back to the wind when taking samples. Sampling of petroleum products should be carried out with at least two people present.

Explosion-proof lamps must be installed on loading and unloading racks. Sampling should be carried out in special clothing and shoes made from materials that do not accumulate static electricity.

To attach the sampler, flexible, non-sparking metal cables must be used, as well as cords (ropes) made of non-electrically conductive materials, on the surface of which a stranded, non-sparking, non-insulated metal conductor connected to the sampler must be attached. The cable or conductor must be grounded before sampling.

2.8. A sample of petroleum product from a railway tank may be taken 10 minutes after the end of its loading. It is prohibited to take samples of petroleum products during a thunderstorm.

2.9. To determine the mass of cargo using the volume-mass static method, it is necessary to have the density of the liquid in the tank at the filling temperature. The density of a liquid is its mass per unit volume. In accordance with the international system of SI units, the kilogram per cubic meter (kg/m3) is used as a unit of measurement for density. For practical purposes, it is permissible to measure density in grams per cubic centimeter (g/cm3). The density of liquid cargo is determined in accordance with GOST 3900 "Oil and petroleum products. Methods for determining density" using hydrometers (Fig. 3) or other special measuring instruments.

Rice. 3 Hydrometer

The hydrometer is a tube 1 sealed on both sides, widened downward. In the narrow upper part of the hydrometer there is a scale 2, each division of which corresponds to 0.0005 g/cm 3. A thermometer with a scale of 3 can be placed in the widened part of the device. A hydrometer for oil is made according to GOST 18481.

The petroleum product intended for determining density is poured into a stable glass cylinder (according to GOST 18481), the height of which must be greater than the length of the hydrometer. A clean and dry hydrometer is carefully immersed in the test liquid smoothly and strictly vertically, supporting it by the upper end, avoiding wetting of the part of the tube located above the liquid level. It is necessary to ensure that the hydrometer does not touch the walls and bottom of the cylinder.

After the vertical oscillations of the hydrometer stop, a reading is made along the upper edge 2 of the oil product meniscus, that is, along the wettability boundary of the hydrometer tube 1 (Fig. 4).

The hydrometer reading is measured with an accuracy of 0.0005 g/cm 3 , and the observer's eye should be at the level of the liquid meniscus.

Simultaneously with measuring the density, the temperature of the oil product is determined using a hydrometer thermometer or a separate thermometer (according to GOST 400).

The temperature of the product is measured in all cases directly at the tank immediately after removing the sampler from the tank. It is necessary to ensure that the thermometer does not touch the walls and bottom of the cylinder. Determination of the density of the petroleum product directly at the sampling site is permitted only if the following conditions are met:

• there is a flat, stable horizontal platform that is not subject to shocks and is convenient for taking measurements;
• measuring instruments are completely protected from wind and precipitation.

If the specified conditions are not met, the density of the selected petroleum product sample is determined in a closed room with the obligatory subsequent reduction of the obtained density value to the density of the petroleum product at the average volumetric temperature of the cargo in the tank.

2.10. The density of petroleum products depends on temperature, decreasing with increasing and increasing with decreasing temperature, therefore, for comparison of numerical values, the density determined at 20°C was taken.

In practice, the petroleum product is shipped or received for unloading at a temperature different from 20°C, therefore, to establish compliance with the quality passport (certificate) of the supplier or technical standards set out in GOST or TU, the density determined by a hydrometer in a sample from railway tanks is converted into density at 20°C, using data from GOST 3900 tables.

The quality passport (certificate) contains data on the density of the petroleum product at a temperature of +20°C. Then the density of the oil product ρ t, [g/cm 3 ] at any temperature t can be determined by the formula:

Where ρ 20- density of the petroleum product at a temperature of 20°C according to the quality passport (certificate), g/cm 3 ;
α - temperature correction of density per 1°C, g/cm 3 .

Temperature correction a is determined based on the density of the oil product at a temperature of 20°C according to table. 2.

table 2

Density of petroleum product at 20°C, g/cm3	0,6900 ÷ 0,6999	0,7000 ÷ 0,7099	0,7100 ÷ 0,7199	0,7200 ÷ 0,7299	0,7300 ÷ 0,73999	0,7400 ÷ 0,7499	0,7500 ÷ 0,7599	0,7600 ÷ 0,7699	0,7700 ÷ 0,7799	0,7800 ÷ 0,7899	0,7900 ÷ 0,7999	0,8000 ÷ 0,8099	0,8100 ÷ 0,8199	0,8200 ÷ 0,8299	0,8300 ÷ 0,8399	0,8400 ÷ 0,8499	0,8500 ÷ 0,8599	0,8600 ÷ 0,8699	0,8700 ÷ 0,8799	0,8800 ÷ 0,8899	0,8900 ÷ 0,8999
	9,10	8,97	8,84	8,70	8,57	8,44	8,31	8,18	8,05	7,92	7,78	7,65	7,52	7,38	7,25	7,12	6,99	6,86	6,73	6,60	6,47

2.11. Sometimes the accompanying documents indicate the density of the petroleum product, determined at a temperature of +15°C. If data on the density of the cargo at 20°C is not available, the formula is used to compare the density of the petroleum product at its real temperature with the density at 15°C:

In this case, the temperature correction of density by 1°C a is taken according to the data in table. 3.

Table 3

Average temperature corrections for the density of petroleum products

Density of petroleum product at 15°C, g/cm3	0,6945 ÷ 0,7044	0,7045 ÷ 0,7143	0,7144 ÷ 0,7243	0,7244 ÷ 0,7343	0,7344 ÷ 0,7442	0,7443 ÷ 0,7541	0,7542 ÷ 0,7640	0,7641 ÷ 0,7740	0,7739 ÷ 0,7839	0,7840 ÷ 0,7938	0,7939 ÷ 0,8039	0,8038 ÷ 0,8137	0,8138 ÷ 0,8236	0,8237 ÷ 0,8336	0,8337 ÷ 0,8435	0,8436 ÷ 0,8535	0,8536 ÷ 0,8634	0,8635 ÷ 0,8733	0,8734 ÷ 0,8832	0,8833 ÷ 0,8932	0,8933 ÷ 0,9031
Temperature correction per 1°C, (·10 -4) g/cm 3	9,10	8,97	8,84	8,70	8,57	8,44	8,31	8,18	8,05	7,92	7,78	7,65	7,52	7,38	7,25	7,12	6,99	6,86	6,73	6,60	6,47

3. The procedure for determining the volume of liquid in a railway tank.

3.1. The volume of liquid in tanks is determined according to the "Calibration Tables for Railway Tanks", based on the type of calibration of the tank and the filling height.

The calibration type of the tank is indicated only by standard metal numbers welded to the side surface of the boiler under the tank number.

3.2. The height of oil product loading is determined by a special measuring device - a meter rod, which is a metal composite pipe with a scale length of up to 3.5 m. The price of the smallest scale division is 1 mm.

3.3. The filling height is measured at two opposite points of the manhole (cap) along the longitudinal axis of the tank at least twice at each point. To take measurements, the meter rod is smoothly and strictly vertically lowered through the manhole to the lower generatrix of the boiler. It is necessary to avoid sharp impacts on the bottom of the tank and ensure that the meter rod does not rest against protruding parts of the tank and universal drain device, ladders or other foreign objects. Lowered until it comes into contact with the bottom generatrix of the boiler, the meter rod is quickly and smoothly removed. The filling height in centimeters is measured along the wetting line of the meter rod with the oil product. The discrepancy between two measurement readings should not exceed 0.5 cm, otherwise the measurement is repeated. The arithmetic mean of the results of measurements taken at two opposite points is taken as the height of oil product loading. The result obtained is rounded to the nearest centimeter: a value less than 0.5 cm is discarded, and 0.5 cm or more is taken as a whole centimeter.

3.4. When measuring the filling height of light petroleum products (especially gasoline), it is recommended to rub the meter rod scale in the area of ​​the intended reading with chalk to better determine the wetting line.

3.5. Based on the resulting filling height in centimeters for each calibration type, the volume of oil product poured is determined using the corresponding calibration table.

The accuracy of determining the mass of the cargo in the tank depends on the correct measurement of the loading height, density and temperature of the oil product.

3.6. Calculation of the mass of petroleum products in tanks using the volume-mass static method.

To determine the mass of an oil product using this method, you must:

• measure the filling height with a meter rod;
• take a sample of the product from a level corresponding to 0.33 of the tank diameter, counting from the bottom generatrix of the boiler;
• immediately after removing the sample from the tank, measure the average volumetric temperature and density of the oil product with a hydrometer;
• establish the calibration type of the tank according to the corresponding signs on its boiler;
• according to the measured filling height, determine the volume of oil product using the appropriate calibration table;
• calculate the mass of the oil product in the tank by multiplying the volume of the oil product determined from the calibration tables by its density at the average volumetric temperature in the tank.

3.7. Instruments used to determine the mass of petroleum products (thermometer, hydrometer, meter rod) must be verified and have the appropriate stamps and certificates of the State Verifier.

3.8. An example of determining the mass of liquid cargo by calculation.

Initial data. The petroleum product is transported in a tank of calibration type 62. Loading height set by a meter rod: 2746 mm. Density of the petroleum product at a temperature of +20°C, according to the quality certificate: 0.824 g/cm 3 . Cargo temperature in the tank according to measurements: -12°C. It is necessary to determine the mass of the transported petroleum product. Calculation. The mass of the oil product is determined by the formula:

Where V- volume of cargo in the car, dm 3;
ρ - cargo density, kg/dm 3.

The cargo volume at a filling height of 275 cm (according to the rounding rules, 274.6 cm is rounded up to 275 cm) for this type of tank in accordance with the Calibration Table (type 62) is 69860 dm 3.

Density of oil product at a given temperature:

1. The temperature difference is determined to be +20°C - (-12°C) = 32°C;
2. The temperature correction per 1°C according to Table 2 of average temperature corrections for the density of petroleum products for a density of 0.8240 kg/dm 3 will be 0.000738 kg/dm 3 ; accordingly, at 32°C it will be 0.000738´32 = 0.023616 kg/dm 3, or rounded 0.0236 kg/dm 3;
3. At a cargo temperature of more than +20°C, the resulting product (0.0236 kg/dm3) is subtracted from the density value at +20°C, and when the temperature of the oil product in the tank is below +20°C, the resulting product is added to the density value at +20 °C.
Point 5, 6

STATE STANDARD OF THE USSR UNION

OIL AND PETROLEUM PRODUCTS

METHODS MEASUREMENTS MASSES

GOST

Petroleum and petroleum products.

Methods of mass measurement

1. General Provisions

2. Measurement methods

3. Errors in measurement methods

Appendix 1. Terms used in the standard and explanations for them

Appendix 2. Mathematical models of indirect methods of mass measurement and their errors

Appendix 3. Examples of calculations of product mass and estimation of method errors

1. GENERAL PROVISIONS

1.1. The standard regulates methods for measuring gross mass and net mass of products.

The main method for export deliveries and commercial operations of oil and petroleum products, except for fuel oil, bitumen and grease, is the dynamic method using meters (flow meters).

1.2. Products must comply with the requirements of current regulatory and technical documentation.

1.3. The terms used in this standard and their explanations are given in the reference Appendix 1.

2. MEASUREMENT METHODS

2.1. When carrying out accounting and settlement operations, direct and indirect methods are used.

2.2. When using direct methods, the mass of products is measured using scales, weighing dispensers and devices, mass counters or mass flow meters with integrators.

2.3. Indirect methods are divided into volumetric and hydrostatic methods.

2.3.1. Volumetric mass method

2.3.1.1. When using the volume-mass method, the volume and density of the product are measured under the same or reduced to the same conditions (temperature and pressure), the gross mass of the product is determined as the product of the values ​​of these quantities, and then the net mass of the product is calculated.

2.3.1.2. The density of the product is measured by in-line density meters or hydrometers for oil in a combined sample, and the temperature of the product and pressure under the conditions of measuring density and volume, respectively, by thermometers and pressure gauges.

2.3.1.3. Determination of the net mass of the product

When determining the net mass of the product, the ballast mass is determined. To do this, measure the water content and the concentration of chloride salts in oil and calculate their mass.

The mass of mechanical impurities is determined by taking their average mass fraction in oil according to GOST 9965-76.

2.3.1.4. Depending on the method of measuring the volume of a product, the volume-mass method is divided into dynamic and static.

The dynamic method is used when measuring the mass of a product directly on the flow in petroleum product pipelines. In this case, the volume of the product is measured by meters or flow converters with integrators.

The static method is used when measuring the mass of a product in graduated containers (vertical and horizontal tanks, transport containers, etc.).

The volume of product in tanks is determined using tank calibration tables based on filling level values ​​measured by a level gauge, metro rod or metal measuring tape. In containers graduated to full capacity, the filling level is controlled and the volume is determined according to the passport data.

2.3.2. Hydrostatic method

2.3.2.1. When using the hydrostatic method, the hydrostatic pressure of the product column is measured, the average area of ​​the filled part of the tank is determined, and the mass of the product is calculated as the product of the values ​​of these quantities divided by the acceleration of gravity.

The mass of the dispensed (accepted) product is determined by two methods:

as the difference between the masses determined at the beginning and at the end of the commodity operation using the above method;

as the product of the difference in hydrostatic pressure at the beginning and end of the commodity operation by the average cross-sectional area of ​​the part of the tank from which the product was released, divided by the acceleration of gravity.

2.3.2.2. The hydrostatic pressure of the product column is measured by pressure gauges taking into account the vapor pressure of the product.

2.3.2.3. To determine the average cross-sectional area of ​​a part of the tank, a metal measuring tape or level gauge is used to measure the product levels at the beginning and at the end of the commodity operation and, according to the tank’s calibration table, calculate the average cross-sectional areas corresponding to these levels.

It is allowed, instead of measuring the level, to measure the density of the product using clause 2.3.1.2 and determine:

filling level to determine the average cross-sectional area as the quotient of hydrostatic pressure divided by density;

volume of oil to determine the mass of ballast as a quotient of mass divided by density.

2.4. Mathematical models of direct methods and their errors are given in MI 1953-88.

Mathematical models of indirect methods and their errors are given in the mandatory Appendix 2.

Examples of product mass calculations and method error estimates are given in the reference Appendix 3.

Note. For foreign trade organizations, if necessary, it is allowed to calculate the mass in accordance with the provisions of the ISO 91/1-82 standard and other international documents recognized in the USSR.

3. ERRORS OF MEASUREMENT METHODS

3.1. The relative error limits of mass measurement methods should be no more than:

with the direct method:

± 0.5% - when measuring the net mass of petroleum products up to 100 tons, as well as the net mass of bitumen;

± 0.3% - when measuring the net mass of lubricants;

with the volume-mass dynamic method:

± 0.25% - when measuring the gross mass of oil;

± 0.35% - when measuring net oil mass;

± 0.5% - when measuring the net mass of petroleum products from 100 tons and above;

± 0.8% - when measuring the net mass of petroleum products up to 100 tons and waste petroleum products;

with the volume-mass static method:

± 0.5% - when measuring the net mass of oil, petroleum products from 100 tons and above, as well as the net mass of bitumen;

± 0.8% - when measuring the net mass of petroleum products up to 100 tons and waste petroleum products;

with the hydrostatic method:

± 0.5% - when measuring the net mass of oil, petroleum products from 100 tons and above;

± 0.8% - when measuring the net mass of petroleum products up to 100 tons and waste petroleum products.

ANNEX 1

Information

TERMS USED IN THE STANDARD AND EXPLANATIONS TO THEM

Gross weight - the weight of oil and petroleum products, the quality indicators of which comply with the requirements of regulatory and technical documentation.

Ballast mass is the total mass of water, salts and mechanical impurities in oil or the mass of water in petroleum products.

Net weight is the difference between gross weight and ballast weight.

APPENDIX 2

Mandatory

MATHEMATICAL MODELS OF INDIRECT METHODS FOR MASS MEASUREMENTS AND THEIR ERRORS

1. Model of the volume-mass dynamic method

	Product weight, kg;
	Product volume, m3;
	Product density, kg/m3;
δ ρ= (tρ - tV)	Product temperature difference when measuring density (tρ) and volume (tv), °C;
	Volume expansion coefficient of the product, 1/°C;
δ ρ =(Pv - P ρ )	Pressure difference when measuring volume (Pv) and density (P ρ ), MPa;
	Compressibility coefficient depending on pressure, 1/MPa.

1.1. Method error model

, (2)

	Relative error in measuring the mass of the product, %;
	Relative error of volume measurement, %;
	Relative error of density measurement, %;
	Absolute measurement error of temperature difference δt, ºC;
	Relative error of the central data processing and display unit, %.

2. Model of the volume-mass static method

	Volumes of product, respectively, at the beginning and end of the commodity operation, determined by the calibration table of the tank, m3;
	Average densities of the product, respectively, at the beginning and at the end of the commodity operation, kg/m3;
	Coefficient of linear expansion of the tank wall material, 1°C;
	Temperature difference between the tank walls during volume measurement (tv) and during calibration (tgr), °C.

2.1. Method error model

3. Model of the hydrostatic method

(5) or (6)

	Average values ​​of the cross-sectional area of ​​the tank, respectively, at the beginning and at the end of the commodity operation, m2, determined How - ( V- product volume, m3, N - container filling level, m);
	The average value of the cross-sectional area of ​​the part of the tank from which the product is released, m2;
	Gravity acceleration, m/s2;
	Product pressure at the beginning and end of the commodity operation, Pa;
	Product pressure difference at the beginning and end of the commodity operation, Pa.

3.1. Method error model

for formula (5)

for formula (6)

where ΔSi, ΔSi +1	Relative errors in measuring the cross-section of the tank, respectively, at the beginning and at the end of the commodity operation, %;
ΔРi , ΔPi+1	Relative errors in measuring pressure, respectively, at the beginning and at the end of a commodity operation, %;
	Relative error in measuring the pressure difference ξР, %;
	Relative error in measuring the average cross-sectional area of ​​the tank from which the product was released, %.

4. Models for measuring net oil mass

When using the volumetric mass method of measuring mass:

When using the hydrostatic mass measurement method:

, (10)

	Net weight of oil, kg;
	Ballast weight, kg;
	Volume fraction of water in oil, %;
	Density of water, kg/m3;
	Concentration of chloride salts, kg/m3;
	Normalized mass fraction of mechanical impurities in oil, %.

4.1. Method error models

for formula (9)

(11)

for formula (10)

Note. Errors in measuring the parameters β, γ, δр,α, , are not taken into account in the error models of the methods due to their small influence.

APPENDIX 3

Information

EXAMPLES OF CALCULATIONS OF PRODUCT MASS AND ASSESSMENT OF METHODS ERRORS

1. Volume-mass dynamic method

1.1. When applying the volume-mass dynamic method, the following measuring instruments are used:

turbine meter with limits of permissible values ​​of relative error (hereinafter referred to as error) ΔV=±0.2%;

in-line density meter with absolute error δρ =±1.3 kg/m3;

thermometers with absolute error Δt ±0.5°С;

class I pressure gauges with the upper limit of the measurement range Pmax=10 MPa.

The measurement results are processed on a computer with a relative error ΔМ = ±0.1%.

1.2. Measured product volume V = 687344 m3.

1.3. Based on the measurement results during the passage of the volume, the following parameters are calculated (arithmetic average values):

product temperature when measuring volume tV = 32°C;

pressure when measuring volume Pv = 5.4 MPa;

product temperature when measuring density tρ =30°C;

pressure when measuring density Рρ =5.5 MPa;

product density ρ = 781 kg/m3.

1.4. According to the reference books they determine:

coefficient of volumetric expansion of the product β= 8∙10-4 1/°С;

product compressibility coefficient depending on pressure γ = 1.2-10-3 1/MPa.

1.5. The mass of the product passed through the pipeline is calculated using the formula ( 1 )

m = 687344∙781∙ ∙ = kg = 535.9 thousand tons.

1.6. To determine the error of the method, calculate:

relative error in density measurement according to the formula

where ρmin is the minimum allowed in the measurement procedure (MVI)

product density value;

absolute error in measuring temperature difference

1.7. When determining the error of the method, it is taken into account that it reaches a maximum at the maximum permissible excess of temperature tv over temperature tρ, which must be indicated in the MVI. For example, we assume that the MVI is set to 10°C.

1.8. The error of the volume-mass dynamic measurement method is calculated using the formula ( 2 ) applications 2:

2. Volume-mass static method

2.1. When applying the volume-mass static method, the following measuring instruments were used:

steel vertical cylindrical tank with a capacity of 10,000 m3, calibrated with a relative error ΔK= ±0.1% at a temperature tgr = 18°C;

level gauge with absolute error ΔН= ±12 mm;

hydrometer for oil (oil densimeter) with absolute error Δρ = 0.5 kg/m3;

thermometers with absolute error Δt=±1°С.

The measurement results are processed on a computer with a relative error ΔM= ± 0.1%.

2.2. When measuring before releasing the product, the following results were obtained:

product loading height Hi= 11.574 m;

density of the product from the combined sample in laboratory conditions at temperature = 22°C, ρi = 787 kg/m3;

average product temperature in the tank =34°C;

ambient temperature ti = -12°C.

2.3. When measuring after the product was released, the following results were obtained:

product loading height Hi+1 = 1.391 m;

density of the product from the combined sample in laboratory conditions at temperature = 22°C - ρi+1= 781 kg/m3;

average product temperature in the tank =32°C;

ambient air temperature ti+1=-18°С.

2.4. According to the reference books they determine:

coefficient of linear expansion of the tank wall material

α=12∙10-61/°С;

product volumetric expansion coefficient

β=8∙10-4l/°C.

2.5. Using the tank calibration table, determine:

volume of product in the tank before release Vi= 10673.7 m3;

volume of product in the tank after release l/i+1= 1108.2 m3.

2.6. Calculate the temperature of the tank walls:

before releasing the product

after product release

2.7. The mass of the released product is determined by the formula ( 3 ) applications 2:

m = 10673.7∙ ∙784∙ – 1108.2∙ ∙781∙ =353 = 7428101 kg =7430 t.

2.8. To determine the error of the method, calculate:

relative error in measuring product density

:

absolute error in measuring temperature difference:

2.9. When determining the error of the method, it is taken into account that it reaches a maximum at the maximum value for a given tank specified in the passport for the tank, as well as at the minimum difference and maximum temperature rise tv above temperature tρ which must be indicated in the MBI.

2.9.1. In the case under consideration, for example, a tank with =l2 m is used and (Hi-Hi+i)min are specified = 8 m and therefore =4 m and min=min=-10°С

2.9.2. Using the tank calibration table, determine the volumes corresponding to the levels of clause 2.9.1:

2.9.3. To calculate the error, determine the values

And

.

Note. In these calculations, the assumption is made that the density of the product in the tank before and after the end of dispensing and the density of the dispensed product are equal, which does not significantly affect the estimate of the error.

2.10. The error of the volume-mass static method is calculated using the formula ( 4 ) applications 2:

3. Hydrostatic method

3.1. When applying the hydrostatic method, the following measuring instruments are used:

steel vertical cylindrical tank with a capacity of 10,000 m3, calibrated with a relative error ΔК= ±0.1% at temperature tgr=18°C;

level gauge with absolute error ΔH = ±12 mm;

Processing of measurement results is carried out on a computer with a relative error ΔM = ±0.1%.

3.2. The measurements obtained the following results:

product filling height before release Hi = 10.972 m;

differential pressure before release Pi=86100 Pa;

product filling height after release Hi+1= 1.353 m;

differential pressure after release P i+1= 11800 Pa.

3.3. Using the reference book, the value of the acceleration of free fall for a given area is determined as g = 9.815 m/s2.

3.4. Using the tank calibration table, determine:

product volume before release Vi = 10581.4 m3;

volume of product after release Vi+1 = 1297.1 m3.

3.5. The following values ​​are calculated:

when used to calculate the formula ( 5 ) Appendix 2 is the average value of the cross-sectional area of ​​the tank before dispensing the product specified in the passport for the tank, as well as at the minimum value of the dispensed product mmin and its maximum density ρmax, which must be indicated in the MVI.

4.1. When measuring the gross mass of oil, measuring instruments were used and the results given in pp. 1 And 3 .

4.2. Additionally, to measure the net mass of oil, the following were used: a moisture meter with an absolute error Δφв = ±0.18% (by volume),

salt meter with absolute error Δωхс = ±0.25 kg/m3,

hydrometer for measuring the density of water with an absolute error Δρв = 0.5 kg/m3.

4.3. Based on the measurement results during the product release, the following parameters are calculated (arithmetic average values):

volume fraction of water in oil φв = 0.7% (by volume);

concentration of chloride salts in oil ωхс=1.2 kg/m3;

the density of water contained in oil is ρw = 1050 kg/m3.

4.4. The mass fraction of mechanical impurities in oil is assumed to be equal to the limit value for GOST 9965-76, ωmp = 0.05% (by mass).

4.5. When using the volumetric mass method (see. clause 1) net mass of oil is determined by the formula ( 9 ) applications 2:

4.6. When using the hydrostatic method (see clause 3) are preliminarily determined:

The mass of oil in this case is determined by the formula ( 10 ) applications 2:

4.7. When determining the errors of the methods, it is taken into account that they reach a maximum at the maximum permissible values ​​of water density ρw, water content φw and concentration of chloride salts ωxc in oil, at the maximum temperature rise tv above temperature tρ and the minimum permissible value of oil density ρ, which must be indicated in the MVI.

4.7.1. In the case under consideration, for example, the following are specified in the MVI:

4.8. The error of the volume-mass method of measuring net oil mass using the formula ( 11 ) applications 2:

4.8.1. When using the volume-mass static method (see. clause 2) the error is also determined by the formula ( 11 ) Appendix 2, however, it is necessary to determine the error of indirect measurement of volume ΔV , which is calculated by the formula:

4.9. To calculate the error of the hydrostatic method of measuring oil mass, the absolute error of density measurement is first determined (see. clause 3)

The error of the hydrostatic method for measuring net oil mass is calculated using the formula ( 12 ) applications 2:

 

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