RU2743263C1 - System for receiving and dispensing crude oil from reservoir at low temperatures - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to means of receiving, storing and dispensing oil and can be used in oil industry in conditions of low temperatures. System includes a reservoir, two settler filters, a steam line with internal sectional heaters, pipelines for supply and dispensing oil, a pipeline for pumping water, siphon valves, gate valves, steam evaporator, pipeline section with dosing pump and reservoir with depressant additive. Additionally, steam pipeline with seals, pipeline section with dosing pump and tank with depressant additive are installed on oil intake pipeline. Steam reamer is installed on the pipeline of oil receiving tightly by the pipe principle in the pipe, it is made with possibility of movement, it is equipped with external seals and a water drain valve. Pipeline section with dosing pump and vessel is mounted after filters-settlers, in which oil pre-heating is performed.

EFFECT: higher speed of oil separation from water, reduced viscosity and improved oil, as well as destruction of structures of high-molecular weight paraffins.

7 cl, 3 dwg

Description

The proposed invention relates to means for receiving, storing and dispensing oil, and can be used in the oil industry at low temperatures.

Crude oil means a liquid natural fossil mixture of hydrocarbons of a wide physical and chemical composition, which contains water, mechanical impurities, dissolved gas, mineral salts [GOST R 51858 Oil. General technical conditions. M .: GOSSTANDART, 2002].

Mechanical impurities contained in crude oil enter the tank and settle to its bottom. At the same time, a dense sediment layer is formed at the bottom unevenly along the diameter of the tank. The height of the sediment, consisting of mechanical impurities, can reach values of more than one meter. The maximum height is observed near the reservoir inlet valve.

Known reservoir for receiving, storing and separating crude oil from water. [I.A. Elansky, Yu.A. Matveev. Utility model patent No. 62909 dated 05/10/2007].

In this utility model, dispensing nozzles, siphon taps and a drainage nozzle are additionally installed on a tank for dark oil products equipped with heaters. In particular, instead of one dispensing nozzle and one siphon valve, three dispensing nozzles and three siphon valves are installed vertically at distances corresponding to the rules for the construction of vertical, cylindrical, steel tanks for oil and oil products. Recommended nominal sizes of branch pipes are 100, 150, 200 and 250 mm. [Rules for the construction of vertical cylindrical steel tanks for oil and oil products. M. (Resolution of the Gosgortekhnadzor of Russia No. 76) 2003]. The branch pipes are equipped with valves of the appropriate diameter and pipelines.

At the same time, a drainage pipe is welded to the lower part of the tank wall, which is equipped with a valve and a pipeline. Through the pipeline, water, with the help of a pump or by gravity, flows into a separate tank, from where it is then pumped out into a special well or container.

Additional siphon taps are designed to determine the water level in the tank. The use of the second and third additional dispensing nozzles located above the main dispensing nozzle allows solving the problem of more efficient delivery of crude oil from the proposed reservoir for further preparation. The installation of additional dispensing and drainage nozzles, as well as siphon valves allows continuous pumping of crude oil that is above the water level. At the same time, simultaneously with pumping, there will be an accelerated separation of water from crude oil due to the use of internal heaters, as well as drainage of water from the reservoir using a drainage pipe, gate valve and pipeline communications.

This reservoir solves the problem of constantly decreasing the level of crude oil by pumping oil liquid and water using additional equipment.

The disadvantages of this reservoir when receiving crude oil are:

1. Absence of a device that significantly reduces the ingress of mechanical impurities into the tank.

2. The presence of a measurement error due to the sediment, consisting of mechanical impurities.

3. Insufficient performance at low temperatures.

Also known is a tank for receiving, storing and dispensing crude oil containing mechanical impurities. [Yu.A. Matveev, A. Yu. Bogdanov and others. Patent for a useful model No. 79535 dated 01/10/2009].

In this utility model, the tank for receiving, storing and separating crude oil from water is additionally equipped with two filter sedimentation tanks made in the form of a truncated cone and equipped with shut-off valves, pressure measuring instruments, and a device for removing mechanical impurities. The angle at the top of the cone is not more than 60 degrees for the purpose of directed downward movement of the deposited particles under the action of gravitational forces. The design and working volume of the filter should provide sufficient time for the crude oil to remain in the settler for the most complete sedimentation of coarse mechanical impurities, which are the main factor in the formation of sediment at the bottom of the vertical steel tank RVS.

The vertical steel tank has inlet, outlet, drainage and ventilation nozzles, gate valves, siphon taps, skylight and gauge hatches, a manhole, a breathing valve, pipelines for receiving and discharging oil and water, internal sectional heaters with steam. At the inlet to the reservoir, in front of the gate valve on the receiving pipeline, two sump filters with pressure gauges are installed. Sump filters are equipped with pipelines and shut-off valves to remove mechanical impurities. On the pipelines of the filters, special valves are installed, which allow, when filling the first filter of the sump with mechanical impurities, to turn on the second sump. This reservoir solves the problem of partial sedimentation and removal of mechanical impurities contained in crude oil.

The disadvantages of a tank for receiving, storing and dispensing crude oil containing mechanical impurities are:

1. Low efficiency of filtration and sedimentation of mechanical impurities contained in crude oil.

2. The presence of measurement error in the tank due to sediment, consisting of mechanical impurities.

3. Insufficient performance at low temperatures.

The closest in technical essence to the proposed utility model is an installation for receiving and dispensing crude oil and filtering mechanical impurities. [Yu.A. Matveev, A. Yu. Bogdanov and others. Patent for utility model No. 84357 dated 10.07.2009].

The solution to this problem is achieved by the fact that two sump filters equipped with filter nets with cells of various diameters are additionally installed on the receiving pipeline of the tank, to which a pipeline with hot steam is supplied from the tank, equipped with shut-off valves. For ease of maintenance and replacement, filter nets are inserted into special inserts mounted in the sump. Sump filters are equipped with pipelines and shut-off valves to remove mechanical impurities. Special valves are installed on the pipelines of the settler filters, which allow, when the first filter of the settler is filled with mechanical impurities, the second filter is switched on in the settler.

The tank has inlet pipes, a pipeline for oil delivery, gate valves, siphon taps, skylight and gauge hatches, a ventilation pipe, a hatch, a breathing valve, a pipeline for receiving oil, internal sectional heaters with steam, a drain pipe, a pipeline for water drainage latch.

Two sump filters with manometers are installed on the receiving pipeline of the tank. Sump filters are equipped with pipelines and valves to remove mechanical impurities. Special valves are installed on the pipelines of the clarifier filters, which allow, when the first filter of the clarifier is filled with mechanical impurities, the second clarifier is switched on. Additionally, the sedimentation tanks are equipped with two filter nets with cells of different diameters. A hot steam pipeline equipped with valves is supplied to the sedimentation tanks from the reservoir. In the first half of the filter, a mesh with cells of a larger diameter is inserted into a special insert, and then a mesh with cells of a smaller diameter is inserted in the same way.

The technical device works as follows. Through the intake pipeline and the corresponding gate valve, crude oil with mechanical impurities enters the first settler, which is equipped with filtered meshes with cells of various diameters and a hot steam supply pipeline. In the filter, the oil is heated, and part of the mechanical impurities due to gravitational forces are deposited at the bottom of the sump filter. Mechanical impurities of a larger diameter are retained by the first mesh, and of a smaller diameter by the second mesh. The filling of the filter is determined using the difference between the readings of the pressure gauges installed before and after the sump. When the first filter of the sump is filled with the help of special valves, oil is directed to the second filter. In this case, mechanical impurities from the first sedimentation tank are removed through the pipeline by opening the valve. The steam supply is switched from the first filter to the second by means of valves.

The filled filter nets from the first sedimentation tank are removed from the special insert and replaced with new ones. After passing through the sump filter, crude oil enters the tank, where the amount of mechanical impurities is significantly reduced. In the RVS, crude oil is heated by internal heaters using hot steam. Due to its higher density, water settles to the bottom of the tank. After that, the drain valve is opened to pump out water through the pipeline. Having determined the water level in the tank using siphon taps, the operator opens the necessary pipeline valve to pump out the crude oil.

Preliminary removal of mechanical impurities in the sump filter, as well as pumping out of crude oil, separation and drainage of water into a separate tank, can reduce the total level of oil in the VST.

The disadvantages of the installation for receiving and dispensing crude oil and filtering mechanical impurities:

1. Insufficient efficiency at low temperatures.

2. Low efficiency of oil and water separation.

3. Lack of a device for the introduction of additives that reduce the pour point of high molecular weight paraffins.

The proposed invention allows to solve the problem of increasing the efficiency of receiving and dispensing crude oil at low temperatures in order to further prepare it for the production of commercial oil. At the same time, the content of mechanical impurities in oil decreases, the oil temperature and the efficiency of steam use increase, the rate of oil separation from water increases, and the oil viscosity also decreases.

These features are essential for solving the problem of the invention, since the efficiency of settling crude oil from water is increased, the pumping of oil through the pipeline is improved, and the pour point of oil is also reduced.

At low temperatures, a special structure that resembles a crystal lattice of solids can appear in oil, which significantly reduces the fluidity of oil. The purpose of the depressants is to destroy this structure and prevent it from forming again. Usually, the additive is added to heated oil, in which all paraffins are in a dissolved state. Upon subsequent cooling, the pour point depressants prevent the paraffins from solidifying with the formation of a crystal lattice.

The solution to this problem is achieved by the fact that a tubular-type steam expander with seals, a section of the pipeline with a dispenser pump and a container with a depressant additive, as well as a thermometer are additionally installed on the oil receiving pipeline, while the steam expander is installed on the oil receiving pipeline hermetically according to the principle of a pipe in pipe, made with the ability to move along the oil receiving pipeline, equipped with external seals and a valve for draining condensate and water, as well as the fact that the section of the pipeline with a dispenser pump and a tank with a depressant additive is mounted after the filters of the sedimentation tanks in which the oil is preheated.

The essence of the invention is illustrated by drawings (Fig. 1, Fig. 2, Fig. 3), which show: a frontal section of a tank, a sump filter and pipelines with equipment (Fig. 1), a horizontal section of a tank along the line of internal sectional heaters and a top view of filters sedimentation tanks with equipment (figure 2), as well as a frontal section of a steam expander with seals (figure 3).

Vertical steel tank 1, has inlet and outlet nozzles 2, pipeline for dispensing oil 3, gate valves 4, siphon taps 5, skylight and gauge hatches 6, 7, ventilation duct 8, hatch-manhole 9, breathing valve 10, pipeline for oil intake 11, steam line 12 with internal sectional heaters 13, water drain line 14.

On the pipeline for receiving oil 11, two filters for the settling tank are installed. The filters for the settling tanks are equipped with pipelines 16 and valves 17 to remove mechanical impurities. On the pipelines of the clarifier filters, valves 4 are installed, which allow, when the first filter of the clarifier is filled with mechanical impurities, the second clarifier is switched on. Also, in addition, the filters sedimentation tanks 15 are equipped with two filter nets, with cells of different diameters 18, 19. A steam line 12 with hot steam is supplied to the sedimentation tanks 15, equipped with valves 4.

The steam line is equipped with a tubular steam expander 20, which includes a pipeline for receiving oil 11. The steam expander has a larger diameter than the pipeline for receiving oil. Expander 20 is equipped with external seals 21 from the sides, as well as a valve for draining condensate and water 22. The seals are designed to prevent steam leaks. The design of the evaporator is made with the possibility of moving it along the pipeline for receiving oil 11 for the purpose of repair.

Also, a pipeline section 23 with a dispenser pump 24 and a container with a depressant additive 25 is additionally connected to the pipeline 11. Depressant additives are designed to destroy high molecular weight paraffins in order to reduce the pour point (freezing point) of oil.

A thermometer 26 is installed on the oil receiving pipeline to control the oil temperature at the inlet to the reservoir.

The invention works as follows. Through the intake pipeline 11 and the corresponding valve 4, crude oil 27 enters the first settler 15, which is equipped with filter nets 18, 19 with cells of various diameters and a hot steam supply pipeline. In the filter 15, the oil is heated, and part of the mechanical impurities due to gravitational forces are deposited at the bottom of the sump filter. When filling the first filter of the settler with the help of valves 4, oil is directed to the second filter. In this case, mechanical impurities from the first sedimentation tank are removed through the pipeline 16 by opening the valve 17. The steam supply by means of the valves 4 is switched from the first filter to the second.

After the sump filter, a depressant is fed from the tank 25 into the oil supply pipeline using a metering pump 24. The additive is fed into the heated crude oil after passing through the sump filter. Further, the oil in the pipeline is heated in a steam expander 20, which increases the rate of separation of oil from water and decreases the viscosity of the crude oil.

In the RVS, crude oil continues to be heated with the help of internal sectional heaters 13. Water 28, due to its higher density, settles to the bottom of the tank. After that, the corresponding valve 4 is opened for pumping water through pipeline 14. Having determined the water level 28 in the tank using siphon taps 5, the operator opens the necessary valve 4 of the pipeline for pumping out crude oil 3. At the same time, oil and water are pumped out of the tank simultaneously.

Preliminary removal of mechanical impurities in the sump filter, as well as pumping out of crude oil, separation and drainage of water into a separate reservoir can reduce the total level of oil and water in the vertical steel tank.

Multi-stage heating of crude oil in a sump filter, steam expander and in a tank allows:

1. Increase the rate of separation of oil from water.

2. Significantly reduce the viscosity of oil, which contributes to effective pumping of oil at low temperatures.

3. To destroy the structures of high molecular weight paraffins using depressants in order to reduce the pour point (freezing) of oil.

The proposed invention solves the problem of increasing the efficiency of receiving and dispensing crude oil at low temperatures.

Claims (7)

1. A system for receiving and discharging crude oil from a tank at low temperatures, containing a tank, two filter-settling tanks, a steam line with internal sectional heaters, oil supply and discharge pipelines, a pipeline for pumping water, siphon taps, gate valves, characterized in that the pipeline to receive oil, a tubular steam expander with seals, a section of the pipeline with a metering pump and a tank with a depressant additive, and a thermometer are additionally installed. 2. The system according to claim 1, characterized in that the steam expander is installed on the oil receiving pipeline hermetically according to the pipe-in-pipe principle. 3. The system according to claim 1, characterized in that the steam expander is mounted for movement along the oil receiving pipeline. 4. The system of claim 1, wherein the steam expander is equipped with external seals. 5. The system according to claim 1, characterized in that the steam expander is equipped with a valve for draining condensate and water. 6. The system according to claim 1, characterized in that the section of the pipeline with a metering pump and a container with a depressant additive is mounted after filter-settling tanks in which the oil is preheated. 7. The system according to claim 1, characterized in that the pipeline for receiving oil is equipped with a thermometer to control the temperature of the oil.

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