RU2567317C1 - Method of gas separation from admixtures and device for its realisation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method of gas separation from admixtures includes initial centrifugal separation of gas, its contact with liquid, for example washing or methanol water, and repeated secondary separation from drop liquid with vertical and circular discharge. Contact of gas with liquid and following secondary separation is realised simultaneously at straight-flow centrifugal flow of phases, first liquid is sucked up by twisted gas stream, and after the contact of gas with liquid it is displaced. Contact-separation device contains plate with base, in which located is straight-flow centrifugal element with swirler under the base and branch pipe above it, with made on branch pipe generator channels for liquid output, directed tangentially relative to its radius in point of output above the belt. In lower part of straight-flow branch pipe, installed on the plate base, made tangential channel for liquid input is made. Height of channel for gas-liquid mixture output, located on generator of straight-flow branch pipe, is determined by formula h = πd/n, where π = 3.14159, d is branch pipe diameter, m, n is number of slots by diametric cut of branch pipe.

EFFECT: increase of separation efficiency, reduction of number of technological sections or apparatuses in carrying out process of centrifugal separation.

4 cl, 5 dwg

Description

The group of inventions relates to methods for separating liquid from gas and devices for their implementation, for example, before processes for drying gas from moisture or processes of its compression.

A known method of separating gas from impurities before the processes of drying it directly in the bottom of the absorber in the built-in separation sections (RF patent for the invention No. 2155092; IPC7 B01D 53/26, B01D 53/14, priority dated July 6, 1999). This technical solution reduces the number of units of technological equipment, therefore, reduces the building area and capital costs during the construction of such plants.

The disadvantage of this technical solution is the low efficiency of gas separation from liquid droplets of well products saturated with salts, which leads to salinization of the desiccant - glycol, and the need for its frequent replacement or leads to the deposition of salts on the compressor parts when they are introduced into the process due to a drop in gas pressure at a late stage of field operation.

A known method of gas separation (Author's certificate No. 965486; MPK3 B01D 53/26, priority dated 06/11/1981. Gas dehydration method.), In which the separation efficiency is increased by washing the gas after the initial separation with liquid - condensation moisture, evaporated from the absorbent (saturated glycol) ) with a minimum content of soluble salts, and separation from liquid droplets after contact on a separate section. This technical solution allows to increase the service life of the absorbent glycol.

The disadvantage of this method is the lack of efficiency of the secondary separation of droplet liquid and the use of two sections: washing and subsequent secondary separation of gas, which increases the height of the apparatus.

A device for implementing a method of separating liquid from gas (Siebert G.K., Zaporozhets E.P. and Valiullin I.M. Reference book. "Preparation and processing of hydrocarbon gases and condensate, technology and equipment", LLC "Nedra Business Center", 2008, p. 208-209), including a base with centrifugal elements installed on it with swirls at the inlet and droplets at the outlet — the primary separation stage, and a conical surface installed at the exit of the centrifugal elements — the secondary separation stage. The use of two stages of separation in series in one swirling flow improves the efficiency of phase separation.

The main disadvantage of this device is the need for frequent replacement of filters, which does not allow its use in continuous gas separation processes.

A contact device is also known (Author's certificate No. 856480; MPK5 B01D 3/30, B01D 45/12, priority dated 04/03/1978) (prototype for the method and device), including a straight-through pipe with a swirl located at the inlet and a dropper at the outlet, moreover, the nozzle is made with an expanding slit along its entire height with overlapping of the outer edge of the inner slit installed at an acute angle to the generatrix of the nozzle, and the nozzle is equipped with an adjustment device located between the edges.

The disadvantages of this device are:

- the expansion of the slit is made in the direction of the swirl, because the outer edge of the slit is located at an acute angle to the generatrix, while the amount of liquid withdrawn through the slit increases toward the swirler. The expansion of the gap in the direction of the gas outlet increases the secondary ablation with the fluid taken from it;

- the use of one slit over the entire height of the nozzle requires an increased nozzle height, because the selected fluid must make at least one revolution inside the nozzle;

- the contact device requires a section or apparatus for preparing the initial gas-liquid mixture.

The single technical result of the group of inventions is to increase the separation efficiency, reduce the number of technological sections or apparatuses during centrifugal separation processes with increased efficiency.

A single technical result in the implementation of the group of inventions on the subject - the method - is achieved by the fact that in the method of separating gas from impurities, including primary centrifugal gas separation, contacting it with a liquid, subsequent secondary separation from a dropping liquid with vertical and ring extraction, contacting the gas with the liquid and the subsequent secondary separation is carried out simultaneously with a direct-flow centrifugal flow of phases, first the liquid is sucked in by a swirling gas stream, and after the gas contacts the liquid they displace it with bone.

The separated gas and liquid flows after primary and secondary separation are combined and removed from the process.

A single technical result when implementing a group of inventions on an object - a device - is achieved by the fact that in a contact separation device comprising a plate with a base, in which there is a direct-flow centrifugal element with a swirler under the base and a pipe above it, with liquid outlet channels made on the pipe forming , the height of the outlet channel of the gas-liquid mixture located on the generatrix of the in-line pipe is determined by the formula:

h = πd / n,

Where

π = 3.14159,

d is the diameter of the pipe, m,

n is the number of slots along the diametrical section of the pipe.

The height of the inlet channel of the contact fluid, made on the generatrix of the in-line pipe, is made corresponding to the height of the overflow bar or overflow pipe from the base of the plate on which the pipe is mounted.

The simultaneous implementation of gas contact with the liquid and subsequent secondary separation during the direct-flow centrifugal flow of phases, by first providing suction with a swirling gas flow of liquid, and its subsequent displacement after contact with gas, made it possible to increase the separation efficiency and to exclude the use of separate apparatus or sections, as well as supply supports fluid in a swirling flow.

Combining and removing the separated gas and liquid flows after primary and secondary separation from the process will reduce the length of the processing lines and simplify their disposal, for example, re-injection with one stream into the reservoir.

Determining the height of the outlet channel of the gas-liquid mixture located on the generatrix of the straight-through pipe, according to the formula:

h = πd / n,

Where

π = 3.14159,

d is the diameter of the pipe, m,

n is the number of slots in the diametrical section of the pipe,

allowed to determine the optimal height of the direct-flow centrifugal nozzle.

Ensuring the correspondence of the height of the inlet channel of the contact fluid made on the generatrix of the in-line pipe, the height of the overflow bar or overflow pipe from the base of the plate on which the pipe is mounted, made it possible to ensure optimal contact fluid absorption for cleaning the gas stream from salts and solids and enriching it with methanol.

The authors are not aware of methods for separating gas from impurities and devices for their implementation, in which increasing the separation efficiency, reducing the number of technological sections or apparatuses during centrifugal separation processes with increased efficiency would be achieved in a similar way.

In FIG. 1 shows a diagram of the process according to the proposed method.

In FIG. 2 shows a general view of a separation device.

In FIG. 3, section AA in FIG. 2.

In FIG. 4, section BB in FIG. 2.

In FIG. 5, section BB in FIG. 2.

The object-method of separating gas from impurities is carried out according to the scheme shown in figure 1, including:

- section of the primary separation of the gas stream I;

- gas flow swirling section after primary separation II;

- a section for contacting a swirling gas stream with a liquid III;

- a section for the secondary separation of the swirling gas stream from the dropping liquid with vertical and annular extraction VI.

The method of separation of gas from impurities is as follows.

The raw gas stream G ₀ (Fig. 1) according to the proposed method from the well is fed to the primary separation section of the gas stream I to the primary separation, from where the pre-cleaned gas stream G _{1 is} selected for supply to the swirling section of the gas stream after the primary separation II, and the separated an aqueous solution with salts and mechanical impurities (stream L ₀ ) is taken from the primary separation section of the gas stream I for withdrawal.

To flush the gas stream from salts and blow it off with methanol after primary separation, the pre-cleaned gas stream G _{1 is} twisted by feeding it with tangential streams g ₁ to the gas stream swirl section after the primary separation II. Then the swirling gas stream G ₂ provide the suction of the contact fluid in the contact section of the swirling gas stream with liquid III. The liquid is sucked in by a tangential flow L ₁ . Contact liquid in the liquid supply section III serves for contacting a stream of L ₂ and the support level by providing it with the overflow stream L ₃ from the back side section III.

After the contact (mass transfer) of the swirling gas stream G ₂ with the contact fluid stream L ₂ with the same swirling gas stream G ₂ , in the section of the secondary separation of the swirling gas stream from the droplet liquid with vertical and ring extraction VI, the spent liquid (which absorbed salt and gave methanol) as heavier tangential flows L ₄ push the same swirling gas stream G ₂ from its periphery.

The residual liquid is finally taken in the upper part of the periphery of the swirling gas stream G ₂ , by ring sampling by flows L ₅ , and the swirling gas stream G ₃ purified from the liquid is taken away in the center.

The separated liquid streams L ₀ , L ₄ and L ₅ are combined and removed from the system by a stream of L ₆ . Minor gas flows g ₂ pushed out with the liquid flows L ₄ are combined with the purified gas stream G ₃ .

The object device is a contact separation device for implementing the method of separation of gas from impurities (Fig. 2-5), contains:

- plate 1 with base 2;

- direct-flow centrifugal element 3 with a swirler 4 and a pipe 5;

- tangential channels of the input of the pre-cleaned gas stream 6 into the swirl 4;

- tangential channels of fluid inlet 7 into the pipe 5, made along the generatrices of the pipe 5;

- tangential expanding channels for the exit of fluid 8 from the pipe 5, made along the generatrix of the pipe 5;

- adjusting device 9 of the tangential channel of the fluid inlet 7;

- overflow bar 10 (or overflow pipe) plates 1;

- dropper 11 installed in the upper part of the pipe 5;

- tube 12 for supplying and maintaining the level of contact fluid in the plate 1.

The device operates as follows.

After preliminary separation of the gas-liquid mixture, the gas enters the tangential channels of the inlet of the pre-cleaned gas stream 6 into the swirl 4 of the direct-flow centrifugal element 3, where it is twisted and enters the pipe 5 of the direct-flow-centrifugal element 3. Passing the lower part of the pipe 5 installed on the base of 2 plates 1 , with the contact fluid through the tangential channel of the fluid inlet 7, the swirling gas stream sucks the contact fluid into the nozzle 5, where there is intense mass transfer between the liquid and gas shaped phases in a swirling flow, at the same time, salts are transferred to the contact liquid from droplets carried away after preliminary separation, and (or) methanol is blown out of them. Next, the resulting gas-liquid mixture is separated in several stages by centrifugal separation. First, the liquid as heavier through the tangential expanding channels of the fluid outlet 8, made in the nozzle 5, is displaced from it onto a plate 1 with a swirling gas stream, from which it is then taken through an overflow bar 10 (or overflow pipe). Subsequent centrifugal separation of the liquid is carried out on the dropper 11 by an annular selection of liquid thrown off by a swirling gas stream onto the inner walls of the nozzle 5 and moving along an ascending helix. Gas, as a less light phase, is taken in the center from the top of the nozzle 5.

Thus, in the method of separating gas from impurities and the device for its implementation, a single technical result is achieved, which consists in increasing the separation efficiency, reducing the number of process sections or apparatuses during centrifugal separation processes with increased efficiency, by performing a pre-twisted gas stream during secondary separation sequential suction with a swirling gas stream of the washing liquid stream and its subsequent cleaning from drip liquid centrifugal separation with vertical extraction liquid around the periphery of the swirling gas stream and the annular extraction liquid in the upper part of the periphery of the swirling gas flow.

Claims (4)

1. A method of separating gas from impurities, including primary centrifugal gas separation, contacting it with a liquid, for example flushing or methanol water, subsequent secondary separation from a dropping liquid with vertical and ring extraction, characterized in that the gas is contacted with the liquid and the subsequent secondary separation at the same time, during direct-flow centrifugal flow of phases, the liquid is first sucked in by a swirling gas stream, and after the gas contacts the liquid, it is superseded. 2. The method of separating gas from impurities according to claim 1, characterized in that the separated flows of gas and liquid after the primary and secondary separation are combined and removed from the process. 3. Contact separation device, including a plate with a base, in which there is a direct-flow centrifugal element with a swirler under the base and a pipe above it, with liquid exit channels made on the pipe forming the pipe, which are directed tangentially relative to its radius at the exit point above the web, characterized in that in the lower part of the straight-through pipe installed on the base of the plate, a tangential channel of fluid inlet is made, while the height of the outlet channel of the gas-liquid mixture located at and forming a direct-flow pipe, determined by the formula:
h = πd / n,
Where
π = 3.14159,
d is the diameter of the pipe, m,
n is the number of slots along the diametrical section of the pipe. 4. The contact separation device according to claim 3, characterized in that the height of the contact fluid inlet channel made on the generatrix of the once-through pipe is made corresponding to the height of the overflow bar or overflow pipe from the base of the plate on which the pipe is mounted.

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