RU2655361C2 - Method for cleaning gas from liquids and impurities and device implementation thereof - Google Patents

Abstract

FIELD: gas industry.

SUBSTANCE: group of inventions relates to a method and a separator for purifying gas from a liquid and impurities at gas, petroleum and petrochemical industries and can be used in gas and oil fields, as well as at compressor stations of main gas pipelines. Above method includes supplying raw gas through the inlet pipe to the separator, purification of gas in the preliminary stage with simultaneous rotary motion, feeding the gas to an additional stage of purification and then to the final stage of purification and removal of the purified gas and separated liquids and impurities. At the same time, at an additional stage of purification, the gas is sent to the shell, made in the form of a truncated cone and turned with a base in the upper part of the separator, through gas distribution nozzles, one of which is installed in the intermediate section of the shell, and the other at the base of the shell. Next, the separated impurities are directed along the outer wall of the shell into a collector of film liquid attached to its apex and they are removed through a drain pipe installed in the bottom of the separator, installed in the film liquid collector.

EFFECT: group of inventions provides an increase in the degree of gas purification and an increase in the efficiency of the separator.

14 cl, 2 dwg

Description

The group of inventions relates to the field of gas purification from liquids and impurities at gas, oil and petrochemical industries and can be used in gas and oil fields, as well as at compressor stations of gas pipelines. More specifically, the invention relates to technological equipment, namely a separator device in which the gas is cleaned of liquid and impurities in several stages.

Oil and gas fields in the northern regions of Russia are characterized by a high condensate content, its low density and high moisture saturation of the gas. In this regard, certain requirements are set for the creation of the main technological equipment for gas treatment.

The traditional way of gas purification from liquids and impurities in a multi-stage separator is that the raw gas is fed through the inlet pipe to the unit of the preliminary purification stage, then the gas is sent to the next purification stages, the amount and equipment of which depends on the specific conditions of use of the separator, after the final stage of purification remove the purified gas and the separated liquid and impurities from the corresponding nozzles [1].

However, the development of new technical solutions for highly efficient separation devices, which ensure the required degree of gas purification in one apparatus, as well as improved apparatus units and optimization of technological parameters of equipment operation, remains an urgent problem.

Known gas-liquid separator (patent RU No. 80767 U1, publ. 02.27.2009), in which there is a multiple phase separation of the initial mixture. The device comprises a housing with nozzles for the inlet of the gas-liquid mixture and the outlet of gas and liquid. A coagulator, a droplet eliminator installed in front of the gas outlet pipe, and a gas distribution element are placed in the housing. Between the drop eliminator and the coagulator, a partition is installed in the form of a glass turned upside down, located at a distance from the body wall, fixed with lower edges to the base of the coagulator, the bottom of the glass is made with bent elements directed upward. The gas distribution element is made in the form of a tube with a swirl and a narrowed end directed along the gas-liquid mixture.

This device has disadvantages such as:

- the location of the partition in the form of a glass turned upside down at a certain distance from the wall of the body causes the formation of non-working (not involved in the separation process) zones, and also leads to an increase in the diameter of the apparatus;

- uneven distribution of gas-liquid load on the first stage of separation;

- the conditions for draining the liquid from the final stage of separation are difficult due to the formation of vortex zones around the perimeter of the droplet eliminator.

Another separator is known (patent RU No. 2321442 C1, publ. 10.04.2008), in which the gas is cleaned from liquids and solids. It includes a housing, nozzles for the inlet of the gas-liquid mixture and the outlet of gas and impurities. In the upper part of the casing there is a final gas cleaning stage, which is a cyclone element mounted between the upper and lower gratings; a plate is located under the lower grate (impurity collection hopper). A device for preliminary gas purification is mounted near the gas inlet pipe, while simultaneously providing organized rotational movement of gas, a protective sheet is mounted below the gas inlet pipe over the impurity collector. The cavity formed between the protective sheet and the plate is a zone for additional gas purification.

The disadvantages of this device are:

- uneven distribution of gas-liquid load on the cyclone elements due to swirling of the cleaned stream by the gas pre-treatment device;

- it is difficult (structurally not optimized) to remove impurities in the area under the lower plate of the minicyclone hopper - only draining along the walls of the apparatus is ensured;

- the cavity for additional gas purification is the free volume of the apparatus and is used for additional separation of impurities, however, its effectiveness depends on the speed of the gas stream and the sufficient volume of the free zone for swirling the flow by the input device.

Known separator for drying gas (patent RU No. 22252813 C1, publ. 27.05.2005), in which the process of gas purification from impurities, mainly various kinds of liquid media, also takes place. The separator includes a housing with nozzles for the inlet of the crude gas, the outlet of the purified gas and the outlet of the liquid and the inlet and outlet filter sections located in the housing. The inlet filter section is made in the form of a plate mounted above the gas inlet pipe with direct-flow centrifugal separation elements and a gas distribution device placed under it, made in the form of a truncated cone or a truncated pyramid expanding from the bottom up, in the inlet and intermediate section of which there are guide rails with rectangular or square holes, while the guide grilles are made of vertically mounted flat plates, the height of which is equal to the length of one sides of the square hole or smaller side of the rectangular opening. The output filter section is made in the form of at least two collapsible plates located one above the other with ring mesh nozzles, and a gas distribution grill is located between the plates. The distance between the filter sections is from 0.7 to 1.0 of the inner diameter of the housing.

Such a separator has several disadvantages. Increasing the efficiency of the separator is carried out only by organizing a more rational gas supply to the separation elements. However, in the event that the feed rate of the gas-liquid mixture is increased, it is possible to under-load the peripheral centrifugal separation elements by gas. The location of the guide grid in the inlet and intermediate sections of the conical gas distribution device can degrade gas distribution at high gas-liquid flow rates and create excessive hydraulic resistance, in addition, it cannot provide a uniform load on the peripheral separation elements installed above it. The indicated height of the guide rail plates is not optimal. The distance between the inlet and outlet filter sections from 0.7 to 1.0 of the inner diameter of the separator housing increases the weight and size parameters of the apparatus and the metal consumption. There is no organized discharge of liquid at the inlet stage, and, therefore, the liquid that forms on the outer surface of the cone will be picked up by a gas stream and sent to centrifugal separation elements. This leads to a decrease in efficiency and deterioration in the quality of gas purification.

The technical problem to which the present group of inventions is directed is to create a separation device in which the method of gas purification from liquid and impurities is carried out in several stages, with increased requirements in terms of efficiency and reliability, while maintaining the weight and size parameters of currently existing devices or their possible reduction.

The problem is solved by a new method of cleaning gas from liquids and impurities, in which such well-known technological methods as supplying untreated gas through the inlet port of the separator, gas purification at a preliminary stage with the simultaneous organization of rotational motion, directing gas to an additional purification stage and further to the final stage of purification, the conclusion of the purified gas, the output of the separated liquid and impurities, has the following distinctive features. At an additional purification stage, the gas is sent to the shell, made in the form of a truncated cone and turned with the base to the upper part of the separator, through at least two gas distribution nozzles, one of which is installed in the intermediate section of the shell, and the other at the base of the shell, the separated impurities are directed externally the wall of the shell in the collector of film fluid attached to its apex and then organize their removal through at least one drain pipe installed in the film fluid collector, to the direction to the bottom of the separator.

In addition, the task will be solved if:

- at the final stage of purification, gas is directed through a plate onto which centrifugal or contact separation elements are installed;

- at an additional cleaning stage, the gas is directed through gas distribution nozzles, which are made in the form of perforated plates with plates with vertically mounted plate regular grilles;

- at an additional purification stage, the gas is directed through gas distribution nozzles, in which each hole in the plate is aligned with the cell channel formed by a regular plate grating installed on top.

Also, the task is carried out using the proposed device of the separator, which contains a housing with nozzles of the inlet of the crude gas, the outlet of the purified gas, the exit of liquid and impurities, the site of the preliminary stage of gas purification, a collection of liquids and impurities located in the lower part of the housing, a protective sheet mounted above a liquid and impurity collector located above the protective sheet an additional cleaning step and then the final cleaning step. The differences of the device are that the additional cleaning stage includes a shell made in the form of a truncated cone, facing the base in the upper part of the housing, while at least two gas distribution nozzles are located in the shell, one of which is installed in the intermediate section of the shell and the other in the base of the shell, to the top of the shell is attached a collector of film fluid in which at least one drain pipe is installed, directed into the collector of fluid and impurities.

In addition, the task will be solved if the individual structural elements or their relative position with each other will have a private form of execution, namely:

- the shell is made in the form of a truncated pyramid;

- gas distribution nozzles are made in the form of perforated plates with openings with vertically mounted regular plate gratings;

- the holes in the plates are preferably made of round, or square, or rectangular shape;

- the height of the regular plate gratings is from 1.0 to 3.0 of the length of the base forming the channel of the grid cell;

- the free passage section of the plate is at least 30% of the area of the plate and not less than the section of the nozzle of the entrance of the gas-liquid mixture into the separator;

- each hole in the plate is aligned with the channel of the cell formed by a regular plate grid installed on top;

- a collection of film liquid is made in the form of a plate with a flanging directed upwards;

- the final gas purification stage contains a plate with centrifugal or contact separation elements located on it.

- the angle between the wall of the housing and the generatrix of the shell is at least 30 °.

The technical result obtained from the inventions is to increase the efficiency of the separator by increasing the degree of gas purification (reducing the amount of impurities in the gas at the outlet).

In more detail, the invention is explained using the drawings, which schematically illustrate the following:

FIG. 1 - general view of the separator;

FIG. 2 - a fragment of a gas distribution nozzle (top view).

The separator, in which the method of purification of gas from liquids and impurities is carried out, includes a housing 1 with nozzles for the inlet of the crude gas, the outlet of the purified gas, the exit of liquid and impurities. Inside the housing in the upper part there is a final gas purification stage 2, which may contain separation sections with nozzles of various functional purposes, depending on the conditions of use of the separator. For example, it can be a plate with centrifugal or contact separation elements located on it. Liquid drainage from the final stage of gas purification 2 is provided through a drain pipe 10. Near the gas inlet pipe, a unit 3 of the preliminary gas purification stage is installed, which ensures the deviation (swirling) of the incoming flow and the removal of part of the liquid and impurities inertially separated from the gas to the lower part of the apparatus. The node 3 may be a deflecting (fender) plate with a pocket (trap) for removing impurities and a coagulator installed downstream. At the bottom of the separator is a collection of 4 liquids and impurities. A protective sheet 5 is installed below the gas inlet pipe over the liquid and impurity collector 4. The free space zone 11 formed between the protective sheet 5 and the final gas purification stage 2 is an additional gas purification stage. A shell 6 is located in it, made in the form of a truncated cone and facing upwards of the body. At least two gas distribution nozzles 7 are located inside the shell 6, one of which is installed in an intermediate section, and the other at the base of the shell. A collector 8 of film liquid is attached to the top of the shell 6, in which at least one drain pipe 9 is installed, directed to the collector 4 of liquid and impurities. The collection 8 of the film fluid can be made in the form of a plate with a flanging, directed upwards. The volume of the collection 8 of the film fluid and the diameter of the drain pipe 9 are determined on the basis of constructive and technological feasibility.

As an embodiment, the shell 6 can be made in the form of a truncated pyramid, the location and execution of the remaining elements 7, 8 and 9 remains the same.

Gas distribution nozzles 7 can be made in the form of perforated plates with holes mounted on them with regular guide rails. Regular guide rails contain vertically mounted flat plates. The shape of the holes of the plates can be made, for example, round, square, rectangular or any other, structurally and technologically justified. Gas distribution nozzles 7 are characterized by such basic geometric parameters as the height H of regular plate gratings and the length h of the base forming the channel of the grating cell (shown in Fig. 2). The height H of the plate-shaped regular grids is from 1.0 to 3.0 of the length h of the base forming the channel of the grid cell. The recommended free passage section of the plate is at least 30% of the plate area and not less than the section of the nozzle for the entrance of the gas-liquid mixture into the separator. Preferably, if each hole in the plate is aligned with the channel of the cell formed by a plate-shaped regular grid mounted on top. Also, the most optimal geometric parameter will be the angle between the wall of the housing and the generatrix of the shell, which is at least 30 °.

The separator in which the method of purification of gas from liquids and impurities is carried out as follows.

The initial gas-liquid mixture enters the preliminary stage of gas purification through a radially located pipe on the baffle plate and the mesh coagulator of the assembly 3. When the baffle plate deviates from the flow due to centrifugal forces, a part of the liquid droplets and solids from the gas are deposited on the inner surface of the casing, which are discharged into a pocket (trap) for collecting impurities, from where with a part of the gas are directed under the protective sheet 5 into the collector 4 of liquids and impurities. The liquid and impurities that are not separated on the node 3, rise with the gas stream into the zone 11 under the separation sections of the final stage 2 of gas purification. The pre-purified gas goes through an additional purification stage. Under the action of centrifugal forces, a part of the impurities is additionally deposited from the swirling flow onto the inner wall of the housing, which, under the action of gravity in the form of a film, flows under the protective sheet 5. Further along the course of the gas-liquid flow is directed into the passage of the lower section of the conical shell 6, while part of the finely dispersed liquid is deposited on the outer surface of the shell 6 and, under the action of gravity in the form of a film, flows into the collector 8 of the film fluid. Then, the drain pipe 9 is discharged into the collection 4 of liquid and impurities. When the gas-liquid flow passes through the gas distribution nozzles 7, the velocity gradient is aligned over the cross section due to a decrease in the flow velocity during the passage of the conical expansion and the stabilizing action of the guide grids.

The additionally purified gas uniformly enters the separation sections of the final stage 2 of gas purification, where the final gas purification from the liquid takes place. The final stage 2 of gas purification consists of technologically sound devices, for example, plates with centrifugal or contact separation elements.

The purified gas is discharged from the separator through the gas outlet pipe, and the liquid is discharged through the drain pipe 10 into the bottom part of the separator to the minimum permissible level.

The location of one of the gas distribution nozzles 7 at the base of the conical shell 6 allows you to evenly distribute the gas over the entire cross section immediately before the separation section of the final gas purification stage 2, which improves the efficiency of both the peripheral and central zones of this stage.

The organization of the removal of trapped liquid and impurities from the film fluid collector 8 through a drain pipe 9 to the lower part of the separator into the fluid and impurity collector 4 further reduces the liquid load on the higher final gas purification stage 2, which increases the degree of gas purification.

The placement of the conical shell 6 with gas distribution nozzles 7, a film fluid collector 8 and a drain pipe 9 between the protective sheet 5 and the separation section of the final gas purification stage 2, according to the present invention, makes it possible to use the free space zone inside the separator rationally and as efficiently as an additional cleaning stage. In this case, the mass and size parameters of the separator do not increase.

The height of regular plate-shaped gratings of gas distribution nozzles, ranging from 1.0 to 3.0 of the length of the base that forms the channel of the grating cell, is the most optimal geometric parameter that allows to achieve the greatest effect, which is based on the results of gas-dynamic studies and computer simulation.

To ensure uniform gas distribution after the nozzles, it is necessary to provide a certain hydraulic resistance to the gas flow. This is realized by the presence of uniformly distributed perforated holes in the nozzle plates, but with a common bore cross section of at least the area of the gas inlet fitting to the separator to prevent excessive flow resistance.

The optimal distribution of the flow velocity field is ensured if the channels formed by the sides of the cells of the plate regular gratings have at their base a separate hole for supplying a gas stream to the channel.

The collection of 8 film fluid provides the drainage of fluid flowing down the outer surface of the shell 6, and prevents it from falling into the inlet section of the cone. It should also provide the ability to receive fluid around the entire perimeter of the lower section of the conical shell, and thus, can be made in the form of a plate with a flanging, directed upwards, in which a certain amount of liquid can accumulate for subsequent draining along the drain pipe 9.

To ensure a free volume in zone 11 sufficient for effective inertial separation of liquid from gas, the angle between the wall of the separator body and the forming shell is recommended at least 30 °.

The proposed separator is simple in design and does not require large material costs for its manufacture, and all the signs of technical solutions, according to the present invention, can be implemented in technological operations for cleaning gas from liquids and impurities, as well as in specific structural elements (parts, assembly units ) separator using traditional manufacturing techniques.

Moreover, the invention can be successfully applied in separators of various types and purposes, for example, inlet, intermediate, low temperature.

Thus, the inventions provide a more efficient and reliable operation of the separator compared to analogues, can achieve a higher degree of gas purification.

Information sources

1. Collection of scientific papers. DOAO TsKBN OAO Gazprom - 55 years / Ed. G.K. Siebert, Yu.A. Kashchitsky et al. - M: Nedra-Business Center LLC, 2006, pp. 226-231.

Claims (14)

1. A method of cleaning gas from liquids and impurities, including the supply of untreated gas through the inlet port of the separator, gas purification at the preliminary stage with the simultaneous organization of rotational movement, the direction of the gas to an additional purification stage and then to the final purification stage, the output of the purified gas, the output separated liquid and impurities, characterized in that at an additional stage of purification, the gas is sent to the shell, made in the form of a truncated cone and facing the base in the upper part of the separator, through at least two gas distribution nozzles, one of which is installed in the intermediate section of the shell and the other at the base of the shell, the separated impurities are directed along the outer wall of the shell to the collection of film fluid attached to its top and then organize their discharge along the film fluid installed in the collection at least one drain pipe directed to the bottom of the separator. 2. The method of purifying gas from liquid and impurities according to claim 1, characterized in that at the final stage of purification, the gas is directed through a plate onto which centrifugal or contact separation elements are installed. 3. The method of purifying gas from liquids and impurities according to claim 1, characterized in that at an additional purification stage the gas is directed through gas distribution nozzles, which are made in the form of perforated plates with vertically mounted plate plates on them. 4. A method for cleaning gas from liquids and impurities according to claim 3, characterized in that at an additional purification step, the gas is directed through gas distribution nozzles, in which each hole in the plate is aligned with the channel of the cell formed by a regular plate grating installed on top. 5. A separator comprising a housing with nozzles for the inlet of the raw gas, the outlet of the purified gas, the exit of liquid and impurities, the site of the preliminary stage of gas purification, a collector of liquid and impurities located in the lower part of the housing, a protective sheet mounted above the collector of liquid and impurities located above a protective sheet an additional cleaning step and then the final cleaning step, characterized in that the additional cleaning step includes a shell, made in the form of a truncated cone and facing the base in the upper hour housing, while in the shell there are at least two gas distribution nozzles, one of which is installed in the intermediate section of the shell, and the other at the base of the shell, a film fluid collector is attached to the top of the shell, in which at least one drain pipe is installed, directed to collection of liquids and impurities. 6. The separator according to claim 5, characterized in that the shell is made in the form of a truncated pyramid. 7. The separator according to claim 5, characterized in that the gas distribution nozzles are made in the form of perforated plates with plates with vertically mounted plate-like regular grids. 8. The separator according to claim 7, characterized in that the holes in the plates are preferably made of round, or square, or rectangular shape. 9. The separator according to claim 7, characterized in that the height of the regular plate gratings is from 1.0 to 3.0 of the length of the base forming the channel of the grating cell. 10. The separator according to claim 7, characterized in that the free passage section of the plate is at least 30% of the area of the plate and at least a section of the nozzle of the gas-liquid mixture inlet to the separator. 11. The separator according to claim 7, characterized in that each hole in the plate is aligned with the channel of the cell formed by a plate-shaped regular grid mounted on top. 12. The separator according to claim 5, characterized in that the collection of film liquid is made in the form of a plate with a flanging directed upward. 13. The separator according to claim 5, characterized in that the final stage of gas purification comprises a plate with centrifugal or contact separation elements located on it. 14. The separator according to p. 5, characterized in that the angle between the wall of the housing and the generatrix of the shell is at least 30 °.

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