RU2561020C2 - Automatic control and metering system for oil products - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to tools and systems intended for oil products metering, measuring volume, weight and other parameters (density, temperature, etc.), and may be used at oil tank farms. The claimed automatic control and metering system for oil products comprises a tank equipped with depth pressure transducers, bottom unloading device (BUD) for oil and oil products from oil tank cars, automated loading system (ALST) for top loading, automated loading system (ALSB) for bottom loading, metering unit and tank state control, gates, inloading and outloading pipelines equipped with interface pressure sensors.

EFFECT: continuous control over tank state and absolute metering of product flow.

4 cl, 5 dwg

Description

The invention relates to means and systems for accounting for petroleum products, designed to measure volume, mass and other parameters (density, temperature, etc.), and can be used at oil depots.

As a result of a patent search, analogues of the present invention were not identified.

The generally accepted structure of oil depots is known for the sale of light oil products both abroad and in Russia, which includes:

- Storage tanks;

- Overpass plum from the railway. tanks;

- Pumping stations;

- Terminal loading tank trucks with operator.

All objects are connected by product transfer pipelines, through which flows can be redirected by switching valves.

For different types of products, there is a network of pipelines to prevent mixing. Having examined the sections of pipelines from the point of laws of hydraulics, we see that the sections between the overpass and the pumping station belong to the category of suction pipelines, the sections connecting the tanks and loading terminals belong to the same category. The fluid velocity in these areas is limited to 1-2 m per second, so they are built from pipes with a large diameter, respectively, with a large weight and high cost.

Pumping stations of oil depots are equipped with pumps with a capacity of 300 cubic meters per hour and a capacity of 75 kW for receiving product from the railway. tanks. Upon receipt of the product in small batches of 1-4 railways tank pumps are not loaded, while consuming a large amount of electricity.

Accounting for incoming and shipped product is an important factor in the activity of the tank farm personnel. As you know, the balance equation for each type of product has the following form.

RESIDUE AT THE BEGINNING + THE ARRIVAL IN THE TURN OF THE FIRST .-- THE EXPENDITURE AT THE TURN OF THE TRANSFER = THE RESIDUE AT THE END OF THE FIRST.

From the point of view of metrology, having examined these procedures, we can draw the following conclusions:

Reception of a product from railway tanks sealed with seals are made according to the documents, which indicate the mass and other characteristics of the product. Data on the quantity of the product depends on the accounting method used by the organization that loaded the train. the tank. Basically, at most refineries, loading railways tanks are carried out on gallery-type overpasses, where accounting is carried out according to a theoretically calculated table of railway capacity tanks in volume units and density value from which the mass of the product is calculated. Railroad the tank cannot be recognized as a measure of capacity, since this measure is not confirmed either during release or during operation. At some refineries, there are dynamic scales, which, when passing the train from them, pass through them. tanks weigh each tank, but the accuracy of the weighing is insufficient. When using point loading railway. of tanks, each tank is loaded on a scale with an accuracy of mass measurement of plus or minus 50 kg or using Coriolis type mass meters with an accuracy of plus or minus 0.15%. Such methods have reliable results and can be confirmed by exemplary measuring instruments. However, when draining the product from the railway. tanks there are losses due to evaporation and due to the residue on the walls of the tank as a result of wetting. There are also options for the arrival of tanks by underfilling or overflow, which arise due to the reasons of sticking to the walls of a more viscous product and its solidification, as well as the deformation of the tank boiler.

Therefore, in any case, for the reliability of accounting when receiving from the railway. tanks it is necessary to carry out the actual measurement of the amount of product received for an objective information of the balance of movement of the latter for the accounting period.

The product is dispensed from the tanks when loading tank trucks through filling stations having mass or volume meters. The accuracy of the tempering is confirmed by means of control straits with an exemplary measure with a capacity of 2,000 liters with the measurement of actual mass with an accuracy of plus or minus 0.05% by volume and mass.

Removing product residues in the tank is based on data on measuring the level of the product and produced water, and the calibration characteristics of the tank's capacity. However, determining the average density of the product at the current temperature seems to be a problem, therefore, it is impossible to produce a reliable value for removing residues in units of mass.

From the above it follows that during the transshipment of a product through a tank farm there are three types of measurements of the amount of product:

- measurement at loading railway tanks according to its estimated capacity, as well as using weights or mass meters;

- measurement of the amount of product in the tank by calculation method;

- measuring the amount of product when dispensed into tankers using mass meters or volumetric meters.

The indicated measurement methods use different instruments and methods of accounting, which does not contribute to obtaining a reliable result for reducing the balance of the product. As a rule, there are surpluses or shortages of the product, even with an objective approach to the measurement processes.

The main object at the tank farm is the RESERVOIR, which stores the product, the cost of which can reach several hundred million rubles, so it should be constantly monitored by the electronic safety system and all authorized processes related to the receipt and release of the product should be recorded in an independent registrar. Unauthorized events (leak, pressure change: in the tank, inlet and outlet pipelines, temperature, level of produced water) must be recorded by the corresponding sensors and recorded in an independent recorder (in the black box).

To accomplish these tasks, a system is proposed for automatic control and accounting of oil products, containing a tank equipped with hydrostatic pressure sensors, a unit for lower discharge of oil and oil products of railway tank cars (USN), an automated loading system (ASN) for upper loading, an automated filling system (ASN) for lower loading, metering unit for monitoring the status of the tank, valves, receiving and dispensing pipelines equipped with interface pressure sensors.

A single mass meter is used to measure the amount of product during acceptance and dispensing.

The execution of the metering and reservoir monitoring unit is modular in a single box.

The unit of accounting and monitoring the status of the tank can be made multi-channel.

The system of automatic control and accounting of petroleum products provides continuous monitoring of the state of the tank and absolute accounting of the movement of the product.

The invention is illustrated by drawings:

Figure 1 shows the node metering and monitoring the status of the tank.

Figure 2 shows the installation of the USN for the lower drain.

Figure 3 shows the installation of the ASN for the top loading.

Figure 4 shows the installation of the ASN for the lower loading.

Figure 5 shows a diagram of a tank farm with a node metering and monitoring the status of the tank.

Functionality of the automatic control and accounting system for oil products:

- measurement of the amount of product received;

- measurement of the amount of product sold;

- measuring the amount of product in the tank in the interval between acceptance and dispensing at any time;

- tightness control (leaks) of the tank and valves;

- tightness control (leaks) of the inlet and outlet pipelines;

- supply of a product dispensed into tank trucks with its own pump;

- computer control of product acceptance and dispensing operations;

- logging of all events on an independent registrar;

- synchronization with primary equipment connected to the tanker during holiday operations, and with equipment attached to the railway a tank;

- the use of a single mass meter to measure the amount of product during acceptance and dispensing;

- the execution of the metering unit is modular in a single box;

- the module is installed behind the tank embankment;

- the module is connected to a drain installation, which is provided with an individual low-power pump, in the hydraulic part it is made by pipelines operating in pressure mode;

- the module is connected to the loading unit, which does not have a metering function and is equipped only with a control valve, level grounding control devices and a quantity indicator, is also made by pipelines operating in pressure mode;

- pressure pipelines are constantly under a small residual pressure, the value of which is constantly monitored by sensors and each change in the latter is recorded online by the electronic system;

- the module’s filter-gas separator is self-cleaning; cleaning is carried out automatically according to the indications of a pollution sensor.

The system of automatic control and accounting of petroleum products works as follows:

Acceptance of the product from the railway tanks on the overpass are carried out by units for lower discharge of oil and oil products of railway tank cars (USN), equipped with their own pumps with parameters of 100 m3. in hours and a pressure of 3 atm. The installation also includes a manifold with electrically operated valves, which is connected via a non-return valve to a manifold consisting of three or more pressure pipelines. Each manifold pipe designed for the respective product is connected to the metering unit, which is connected to the reservoir of the corresponding product. If necessary, metering units can be several in the number of tanks for a particular product. Each USN discharge unit is equipped with a product availability sensor. The product pipeline from the drain to metering stations should always be filled with the appropriate product with a small residual pressure, the value of which is constantly monitored by the leakage control system. Temperature compensation of volume is carried out by bellows expansion joints located in metering units. Any unauthorized leakage from the pipeline will be recorded in the leakage control system.

The accounting operation during product acceptance is as follows. The USN installation is attached to the railway to the tank, product availability sensors are triggered, and the operator, using a software product on a computer, selects the option of posting the product through the metering unit connected to the reservoir of the corresponding product. The metering unit switches to product acceptance with the help of electrically operated valves included in the metering unit, according to the program, an open pipeline is created in the direction of the tank, which connects the STS to the tank. The pump of the USN installation is started and the product through the metering unit enters the tank until the product availability sensor in the USN installation is triggered. Upon receipt of several railways tanks with a single product are connected to several units of the simplified tax system to the appropriate metering unit. The performance of the metering unit at acceptance is at least 300 m3

Accounting for the product upon acceptance by the metering unit is carried out by a mass meter with simultaneous recording of data on the density, temperature of the product and the received volume. At the end of product acceptance, the metering unit with electrically operated valves according to the program automatically switches to the product release state, while the final results about the received product are issued to the top-level system. All events (operator commands, triggering of all sensors of the command to turn on the motors) are recorded with reference to real time.

Accounting for the product during the holidays to consumers is carried out by the same mass meter, according to which acceptance was carried out with simultaneous fixation of temperature density and volume. The metering unit has a measuring channel for receiving the product and a measuring channel for tempering. The acceptance measuring channel consists of an inlet electrically operated check valve of the mass meter gas separator filter check valve and an output valve, which open during acceptance according to the program, and the valves that block the pump and the discharge pipe are closed. All electrically operated valves have shutter tightness control sensors, the state of which is monitored in real time. The measuring channel for product dispensing consists of an input electrically operated gate valve, an electric pump with a capacity of 100 cubic meters. in hours and with a pressure of 3 atm, valves at the outlet of the pump, mass meter gas separator and valves of the discharge pipeline, which open when the program is released, the other valves close when they are released.

A discharge pipeline connects the metering unit of the corresponding product with an automated filling system (ASN). The discharge pressure pipe, which is constantly filled with the product at rest, is under a slight overpressure, which is monitored by the system for unauthorized leaks. The outlet pipeline has a temperature compensator located in the metering unit to ensure the constancy of the mass of the product in it, which is indirectly involved in the vacation to the consumer.

The outlet pipe ends with a shut-off control valve, which is part of the tanker loading unit. When filling through the upper hatch, the valve is installed at the upper point of the bulk riser. The valve performs the function of supporting a given value of the output tempering and is the point of separation: the product before the valve, the seller’s product after the valve, the consumer’s product, which merges into a tanker using gravity.

When filling from below, the product’s interface is a dry connector consisting of a connecting head and an adapter. The shut-off valve is installed in front of the filling sleeve and performs the function of supporting a given value of the productivity of product dispensing into the tanker. The ASN installation of the top loading used in a system with a metering unit for the product in the tank should include a platform with a ladder and a ladder for operator access to the filling hatch, a shut-off valve and a filling sleeve with a tip. The ASN installation of the lower filling should consist of control and shut-off valves and a filling sleeve with a connecting head.

Each metering station and ASN serve only one type of product. If it is necessary to have two or three filling installations on one product that can work simultaneously, a multi-channel metering unit should be used. It is possible to build a multi-channel product dispensing system with a single-channel metering unit for the product in the tank by using in each ASN installation its own metering devices, for example, turbine meters for the quantity of the product. The total metering of the released product in mass units and the density value will be made by the mass meter installed in the metering unit, and the mass of the released product through a specific channel will be determined by the density value and by the readings of the turbine meter. As a counter, any other type or mass meter may be used.

Accounting for the product in the tank (removal of residues) is carried out by two mutually confirmed methods. According to the readings of the mass meter in the metering unit, as well as the hydrostatic method according to the readings of a temperature-stabilized pressure meter and the calibration characteristic of the tank, determined using a mass meter and a pressure meter, in the coordinates "mass - hydrostatic pressure of the liquid column". Removing product residues in the tank is carried out using the software product at any time. As a result of the use of a single product metering unit in the acceptance and dispensing tank, the objectivity of accounting and determination of the balance of product movement over the planning period are increased, the influence of the human factor is excluded. Metrological support of the measurement process both during acceptance and during tempering is carried out by a mass-produced unit for measuring the mass of volume and density with weighing limits of 1400-1700 kg with a capacity of 2000 cubic meters. dm with accuracy parameters plus or minus 0.05%.

Control of unauthorized product leakage from the tank is carried out by a constantly high-precision hydrostatic pressure sensor, stabilized by temperature, in the absence of acceptance and tempering operations. A change in hydrostatic pressure per mm liquid column in the range from one meter to twelve characterizes the amount of leakage over a fixed period. At the same time, the level of produced water is monitored with fixation of its value at the appointed intervals. Monitoring of leaks in valves, the product pressure in the receiving and dispensing pipelines is carried out using interface pressure sensors by means of their software survey and comparison of their readings with software settings. The tightness control of the connections inside the metering unit is carried out by the product availability sensor installed in the unit's pallet.

In order to return the vapor-air mixture (PVA) when the tankers are hermetically filled into the tank, the PVA recirculation unit is included in the metering unit, which directs the PVA displaced from the poured compartment of the tanker into the vapor space of the tank to replace the volume of the product being dispensed. During product acceptance operations, the PVA is displaced from the tank and fed into the steam space of the railway. tanks to replace the volume of product received. PVA at any ambient temperature has saturated values of light hydrocarbons; when it is directed to the vacant spaces of tanks, instead of air, additional evaporation of light hydrocarbons does not occur. This technology eliminates losses due to evaporation of the product during transshipment operations at the tank farm, as the tanker always has a saturated concentration of PVA, which is displaced during filling and enters the empty space of the tank, thereby preventing the ingress of clean air that is saturated with light hydrocarbons from the product . When accepting a product from railway tanks are sent to them with PVA from the tank, which does not allow to evaporate the received product when pumping it from the railway. tanks.

Claims (4)

1. The system of automatic control and accounting of petroleum products, characterized in that it contains a tank equipped with hydrostatic pressure sensors, a unit for lower discharge of oil and oil products of railway tank cars (USN), an automated filling system (ASN) for upper loading, an automated filling system (ASN ) for lower loading, metering and monitoring unit for the tank, valves, receiving and dispensing pipelines equipped with interface pressure sensors. 2. The system of automatic control and accounting of petroleum products according to claim 1, characterized in that a single mass meter is used to measure the amount of product during acceptance and dispensing. 3. The system of automatic control and accounting of petroleum products according to claim 1, characterized in that the execution of the metering and monitoring unit of the tank is modular in a single box. 4. The system of automatic control and accounting of petroleum products according to claim 1, characterized in that the metering and monitoring unit of the reservoir can be made multi-channel.

Images