RU2393439C1 - Method of calibrating reservoirs - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: reservoir is filled with an oil product to the operating level. Calibration is done under standard operation conditions while discharging fuel through high-precision fuel dispensing units to the minimum possible operating level. Before letting the oil product (OP) through the fuel dispensing units, each fuel dispensing unit (FDU) is adjusted with volume accuracy of 0.04-0.06% with a "plus" sign or a "minus" sign. Taking error into account, volume flow rate of the oil product is determined. Volume flow rate of the oil product is converted to volume flow rate of the oil product in the reservoir based on correction of the temperature coefficient of volumetric expansion of the oil product at the level of discharge from the reservoir. The operation for discharging the oil product with subsequent calibration is repeated until reaching the level corresponding to the minimum operating level. The volume calculation results are summed up, thus determining the volume of the reservoir or part of it. The fuel dispensing unit is adjusted either one before the calibration process or during a long calibration period twice before and repeatedly at the end of the calibration process.

EFFECT: provision for accuracy of calibrating a reservoir using an oil product after emptying once.

3 cl, 1 dwg, 1 tbl, 3 ex

Description

The invention relates to measuring equipment and can be used in fuel depots or tank farms carrying out operations of reception, storage and dispensing of petroleum products.

A device is known (see, for example, the description of copyright certificate No. 1328681, publ. 07.08.87, bull. No. 29) for calibrating tanks, consisting of a tank, a pneumatic system, a centrifugal pump, a flow control throttle with a viewing device, a flow meter, a three-way crane, exemplary measuring device, level gauge with a float, control units, power supply and computing. However, this device does not allow accounting for possible deformations of the tank body.

The device is also characterized by excessive material costs. The possibility of oil products dispensing and regular operation of gas stations (gas stations) and oil bases (NB) is excluded. The measurement accuracy drops during operation and involves the repetition of this operation after a certain time. Metrological stability is low when changing seasons. The temperature difference inside the tank and at the outlet of the fuel dispensers (TRK) is not taken into account, which in turn affects the accuracy of the calibration of the tanks.

A known method of calibrating reservoirs (see RF patent No. 2178153, publ. 10.01.2002, bull. No. 1), including the introduction of the reservoir source data, operating conditions, the use of petroleum products as a working fluid, portions of petroleum products from the reservoir in portions through fuel dispensers columns (fuel dispensers) in normal operation to a level corresponding to its minimum value in the tank, at intervals of calming the released oil, measuring parameters and calculating the calibration of the tank, taking into account Temperature of oil product in dispenser (TRC) and then adjusting the volume holiday, accurate calibration characteristics via measuring tanks.

The known method of calibration involves filling the tank to the maximum value of the spill.

Filling the tank with oil to the maximum inflow rate and dispensing the oil with graduation operations to a level corresponding to the minimum value of the oil in the tank is repeated at least 3-5 times.

Refinement of the characteristics with the help of exemplary measuring devices produced on a shift basis.

Calibration is carried out simultaneously of several or all reservoirs that are in operation of gas stations (oil stations) or oil depots (oil depots) and the operation of all or several fuel dispensers or automated loading risers (ASN) and their combination.

Known methods have several significant disadvantages.

All the main methods involve calibrating tanks in bulk from an empty tank to a max level.

In most fuel depots, due to the increase in the price of petroleum products, their reserves are limited and the tanks are not always filled up to the maximum level and, on the other hand, the lack of oil product in the working tanks can only occur during repair, cleaning, etc. Therefore, calibration should be carried out in the operating modes of the fuel depots, i.e. using standard fuel dispensers (fuel dispensers) to calibrate standard oil products. All calibration operations must be carried out in the tank drain mode.

Calibration of large tanks of 2000 m ³ , 5000 m ³ and more when filling them from fuel dispensers will take a long time, and its repetition 3-5 times is generally difficult to combine with the regular operation of the fuel base.

Low accuracy of standard fuel dispenser-error when dispensing in volume ± 0.25%.

The use of several fuel dispensers will require the repeated use of an exemplary meter to reduce calibration error.

It is necessary to clarify the volumes of oil product (NP) dispensed by the fuel dispensers and the volumes of oil discharged from the tank. In this regard, temperature adjustment in the fuel dispenser and at the level of discharge from the tank should be carried out separately for each fuel dispenser (taking into account the installation location).

The closest in technical essence to the proposed technical solution is a method for calibrating tanks (RF patent No. 2314501, publ. 10.01.2008, bull. No. 1, IPC G01F 25/00), in which the tank is filled with oil (NP) to the operational level, in in the conditions of regular operation directly at the oil bases or fuel dispensing stations, they calibrate in the fuel drain mode through high-precision fuel dispensers (fuel dispensers) to the level that is the smallest possible in operation, after the release of each portion of the oil product is determined dividing the volume of the tank at the discharge level, the correction of the volume of oil discharged from the fuel dispenser to the actual volume discharged from the tank is determined taking into account the difference in temperature of the oil mass measured at the outlet of the tank and from the fuel dispenser.

According to the operating conditions of the fuel depot, it is often impossible to calibrate the tank from the maximum filling height to the min drain level according to operating conditions.

For example, a large number of locomotives are waiting for refueling, and it is not possible to dispense fuel in small doses.

.Calibration of tanks should be carried out with an accuracy of ± 0.2% by volume, while the accuracy of determining the dispensed dose of NP should be three times higher. Thus, the measurement error during dispensing through the fuel dispensers should be

.

Due to the fact that the existing fuel dispensers do not have such accuracy, calibration must be repeated 2-3 times to reduce the error.

An object of the invention is to provide the necessary accuracy of calibrating the tank with a working oil product at one time emptying it by increasing the accuracy of measuring the volumetric flow rate of the oil product when draining through fuel dispensers.

The technical problem is achieved in that in the method of calibrating tanks in which the tank is filled with oil (NP) to the operating level, in normal operation, directly at the oil bases or fuel dispensing stations, calibration is performed in the fuel drain mode through high-precision fuel dispensers (fuel dispensers) to a level value, the minimum possible in operation, after the dispensing of each portion of the oil product, the volume of the tank is determined at the level of discharge, the adjustment of the volume of the NP released from the fuel dispenser is actually released The volume from the tank is determined taking into account the difference in the temperature of the NP measured at the outlet of the tank and from the fuel dispenser, before releasing the NP through one or more fuel dispensers, each fuel dispenser is pre-aligned with an accuracy of 0.04-0.06% in volume with the sign " plus ”or with a minus sign, taking into account the error obtained, determine the volumetric flow rate of NP for one fuel dispenser or the total volumetric flow rate of NP for several fuel dispensers, then recalculate the volumetric flow rate of oil product (NP) released through one sludge and several fuel dispensers, for the volumetric flow rate of the NP in the tank, taking into account the adjustment of the coefficient of volume expansion according to the temperature of the NP at the level of discharge from the tank, the operation of tempering the NP with subsequent calibration is repeated until the level corresponds to the minimum operational level, the obtained volume calculation results are summed up, determining the volume of the tank or its parts, adjustment of the fuel dispenser is carried out either once before the start of the calibration process, or with a long calibration time twice before and again at the end of the cal When adjusting the fuel dispenser again, the resulting error is compared with the error obtained during the first adjustment, with a slight change in the error after the second adjustment, the adjustment is considered stable and calibration is completed, with a strong change in the error, calibration is carried out taking into account the repeated adjustment.

Alignment of each fuel dispenser is performed by a high-precision exemplary measuring device.

When calibrating, horizontal and vertical tanks, diesel engine fuel tanks or tank cars are used as reservoirs.

The proposed method is as follows.

The method for calibrating tanks includes an automated system for metering oil products in vertical and horizontal tanks (for example, Gamma UIP-9602). In this case, the oil product metering system in the tank contains the calibration tables of the tank, determining the levels at which calibration is carried out, and measuring parameters taking into account the temperature of the liquid being filled. Level sensors should be located not less than 20–40 mm apart, and the device for draining from a filled tank is one or several high-precision fuel dispensers. This allows you to calibrate the tank to a certain height (if it is rarely filled completely), and also when draining the oil, partial calibration of the tank is possible in the range of the most used levels (max and min). If there is a technological possibility, then a full calibration of the tanks.

Calibration is performed on the working oil product during the operation of the tanks directly at the oil bases or gas stations in the mode of fuel drain from the tank through high-precision fuel dispensers. Due to the fact that the filling of the tank is connected with the fuel supply limits in tons (or in days of consumption), it is impossible to fill the tank at many fuel bases. Therefore, it is possible to partially calibrate the tank when the tank is filled to a level close to the maximum operational, and then in the drain mode it decreases to a level close to the minimum in operating conditions. In the computing unit of the system, the readings of the counters of the fuel dispensers working with the tank in which the calibration is carried out are recorded.

In the proposed calibration method, the tank calibration system includes a calibrated tank with existing calibration tables (vertical or horizontal), a pipeline connecting the calibrated tank with high-precision fuel dispensers (fuel dispensers), in which a high-precision density meter (measuring oil density and temperature) is located and connected to the pipeline, one or more fuel dispensers, as well as an exemplary measuring device, allowing to determine the volume and masses with high accuracy tempered fuel from the fuel dispenser.

A feature of the proposed method is that when calibrating the tank before releasing the NP through one or more fuel dispensers, each fuel dispenser is aligned using a high-precision exemplary meter, for example UPM-50. The accuracy of adjustment in volume will be 0.04 ÷ 0.06%.

This accuracy is determined with a sign (+) - overflow, and with a sign (-) - underfilling. Given this error, it is possible to obtain the calibration accuracy of the calibrated tank at the level of 0.01 ÷ 0.02% with a known sign ("overflow", "underfilling").

The flow rate for all fuel dispensers connected to the reservoir to be calibrated (separately) is determined for the previous calibration period (in volume).

Examples

1. Consider the calibration of the tank when dispensing through two dispensers. The total volume of NP released through two dispensers is determined. To do this, calculate the total volume of NP by the formula

where ΣV _Trk is the total volume of NP released through two fuel dispensers;

V _TPK1 - the volume of NP released through the first fuel dispenser;

V _TPK2 - volume of NP released through the second fuel dispenser.

Determine the flow rate of each column before calibration by the formula

where ΣV _Trk is the total volume of NP released through two fuel dispensers;

V _TPK1 - the volume of NP released through the first fuel dispenser;

V _TPK2 - volume of NP released through the second fuel dispenser.

Previously, each column must undergo adjustment to obtain the minimum error when measuring the volume of the NP δV = 0.04 ÷ 0.06% (with its own sign).

When dispensing NP through several dispensers, the total amount of NP dispensed through all dispensers is determined by the above formula (1) as the sum of the volumes dispensed through each of several dispensers separately. By the formula (2), the flow rate of each column is determined.

Due to the fact that all measurements were carried out at the dispenser, and the tank is calibrated, the conversion of the volumetric flow rate of the oil product (NP) to the dispenser is calculated at the flow rate in the tank, taking into account the adjustment of the coefficient of volume expansion in temperature, given in the table.

Oil expansion ratios ρ, kg / m ³ β, 1 / ° C ρ, kg / m ³ β, 1 / ° C 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 980.0-989.9 0,00053 830.0-839.9 0,00086 990.0-999.9 0,00052

For the desired density value, measured in the dispenser according to the table, we determine the coefficient of volume expansion for the tank at the temperature of the pump at the level of discharge from the tank.

Given the results obtained, calibrate the tank.

2. Vacation from the tank is carried out through one dispenser.

Prior to the calibration of the tank, the fuel dispenser is aligned with a high-precision exemplary measuring device, for example, UPM-50.

Let the adjustment show a min error δV _min = + 0.05%. Thus, we have a high accuracy of error measurement and this value is not random, but specific - with its own sign (i.e., with the + sign).

If the error will be taken into account with its own sign, then the actual measurement error when dispensing the NP volume through the fuel dispenser will be very close to zero (0.01–0.02%).

If the calibration is carried out for a sufficiently long time, then the calibration of the fuel dispenser can be repeated.

If the error has changed insignificantly by 2 ÷ 5% compared with the first adjustment,

- погрешность измерения при отпуске объема КПП через первую ТРК;Where

- measurement error during tempering of the gearbox through the first dispenser;

- погрешность измерения при отпуске объема НП через вторую ТРК;

- measurement error during tempering of the NP volume through the second fuel dispenser;

then the adjustment can be considered stable and complete calibration; if not, then calibrate it after the second adjustment.

3. Calibration of the tank in "parts".

As mentioned above, according to the operating conditions of the fuel depot, it is often impossible to calibrate the tank from the maximum filling height to the min discharge level according to operating conditions.

For example, a large number of locomotives are waiting for refueling, and it is not possible to dispense fuel in small doses.

Therefore, a "piecemeal" tank calibration may be used. For example, consider a vertical tank 9 m high (see drawing). Let the maximum loading in operation be 7 m. According to the operating conditions of the fuel depot, the low-discharge mode is possible up to the level of 5 m. We calibrate this range. The next calibration is carried out from the level of 3.2 m to the drain tank (at the level of 0.6 m from the bottom). The section from the level of 3.2 m to the level of 5 m remained uncalibrated. This section is calibrated. We begin its calibration from a level slightly higher than 5 m using the calibration data of the upper section of the tank.

When the calibration reaches the level of 3 m and lower, the value of the filling height is taken according to the table of the lower part of the tank, and the value of the upper sections is adjusted. For example, if at the level of 3 m the calibration table of the upper part shows a value greater than 3 m, then you need to reduce the upper calibration by the value (h _in -h _n ) m.

The main advantages of the invention, a method for calibrating tanks, are as follows:

1. High accuracy of column alignment δV = ± 0.04 ÷ 0.06%.

2. Accurate determination of the error of each column with its own sign and its consideration when calibrating the tanks.

3. Checking the stability of the alignment results during the calibration process.

4. The ability to bring the calibration error of the tanks to min values δV = 0.01 ÷ 0.02% with its own sign.

5. The ability to calibrate the tank in the mode of discharge of oil in one pass.

6. Ability to use partial tank calibration according to operating conditions.

Two-speed dispensers are used, which at the beginning of the dose loading and at the end reduce the productivity. After the release of each dose of NP, a “sedation” time of 60 seconds should be provided.

Claims (3)

1. A method of calibrating tanks in which the tank is filled with oil to an operational level, in normal operation, directly at the oil bases or fuel dispensing stations, calibration is performed in the fuel drain mode through high-precision fuel dispensers to the level that is the minimum possible in operation after the release of each portion of the oil product determine the volume of the tank at the drain level, the adjustment of the volume of oil released from the fuel dispensers, to actually released the volume from the reservoir is determined taking into account the difference in temperature of the oil product, measured at the outlet of the tank and from the fuel dispenser, characterized in that before dispensing the oil through one or more fuel dispensers, each fuel dispenser is pre-aligned with an accuracy of 0.04-0.06 in volume % with a plus sign or a minus sign, taking into account the error obtained, determine the volumetric flow rate of the oil product for one fuel dispenser or the total volumetric flow rate of the oil product For several fuel dispensers, then the volumetric flow rate of the oil product dispensed through one or more fuel dispensers is recalculated to the volumetric flow rate of the oil product in the tank, taking into account the adjustment of the coefficient of volume expansion in terms of the temperature of the oil product at the level of discharge from the tank, the operation of tempering the oil product with subsequent calibration is repeated until reaching the value of the level corresponding to the minimum operational, the results of volume calculations are summed up, determined the volume of the tank or its part, while the adjustment of the fuel dispensers is carried out either once before the start of the calibration process, or with a long calibration time twice before the start and again at the end of the calibration process, and when the fuel dispensers are re-aligned, the resulting error is compared with the error obtained when the first adjustment, with a slight change in the error after the second adjustment, the adjustment is considered stable and the calibration is completed, with a strong change in the error, the calibration carried out taking into account re-alignment. 2. The method according to claim 1, characterized in that the alignment of each fuel dispenser is produced by a high-precision exemplary measuring device. 3. The method according to claim 1, characterized in that when calibrating, horizontal and vertical tanks, diesel engine fuel tanks or tank cars are used as reservoirs.