RU2747403C1 - In-line separator - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention can be used in the oil and gas industry for the separation of hydrocarbon condensate and water from natural or associated gas. The in-line separator contains the main channel 1, which is a section of the pipeline with the first swirler 2, the first section of liquid separation 3, and the section for sampling the gas-liquid flow 4, which are sequentially mounted inside it and axially located inside it. which is a section of a pipeline with a second swirler 6, a second liquid separation section 7, a liquid collection section 8 and a liquid collection tank 3 sequentially mounted inside it and axially located inside it, a liquid collection section 8 and a liquid collection tank 3. The liquid collection section 7 is connected by a second additional channel 10 with an ejector 11 located in the main channel 1 between the first swirler 2 and the first liquid separation section 3.EFFECT: invention improves efficiency of the selection of the liquid fraction from the gas fraction.1 cl, 1 dwg

Description

Technology area

The invention relates to the field of devices for separating liquid from gas, in particular, to separators widely used in the oil and gas industry for separating hydrocarbon condensate and water from natural or associated gas.

State of the art

A method for separating gas mixtures by means of axial cyclones is known from the prior art (see [1] RF patent for invention No. 2458298, IPC F25J 3/08, publ. 08/10/2012), in which the separation of water from gas is carried out in a system of two successive axial cyclones. Each cyclone separator includes a swirler, a liquid separation section, and a gas-liquid / liquid flow selection section.

The disadvantage of this analogue is that in the second cyclone separator it is impossible to provide a high efficiency of the selection of the liquid flow from the gas, because A gas-liquid mixture formed in a two-phase boundary layer on the walls of the liquid separation section and representing a suspension of gas and liquid droplets enters the liquid extraction section of the second cyclone separator, which is a slotted cylindrical channel. In this regard, the efficiency of liquid separation in the entire system is rather low.

A thermogasdynamic separator is known from the prior art (see [2] RF patent for utility model No. 74308, IPC B01D 45/12; B01D 53/26, publ. 06/27/2008), including a body, an inlet pipe for an initial multicomponent hydrocarbon gas, a gas swirler , a Laval nozzle, a separation chamber with a condensate outlet, a condensate collector, an ejection chamber with a gas intake branch pipe, branch pipes for removing the gas phase and condensate from the condensate collector, a purified gas flow diffuser, transverse baffles, with each of the transverse baffles made of two parts , the first of which is rigidly connected to the body, the second is located inside the first and is made removable, the nozzle, the separation chamber and the diffuser are installed in series inside the second parts of the transverse partitions. The disadvantage of this analogue is the low efficiency of liquid separation, due to the lack of special devices for liquid separation in the gas recirculation channel connecting the condensate collector and the ejection chamber.

The closest analogue to the claimed invention in terms of a set of features taken as a prototype is a low-temperature separation unit for gas or gas-liquid mixtures (see [3] RF patent for utility model No. 93513, IPC F25J 3/06, publ. 04/27/2010), containing a first cyclone separator connected to a source of a gas or gas-liquid mixture of high pressure, including a channel located along its central axis for supplying a gas or gas-liquid mixture of low pressure and coaxially covering it with a swirler, behind which along the flow there are sequentially placed nozzle and separation channels, and the latter is made with outlets for the two-phase mixture and for the purified gas, while the outlet for the two-phase mixture is connected to the inlet of the separator for liquid separation, the gas outlet of which is connected to the inlet of the second cyclone separator, the outlet for the two-phase mixture of which is connected to the channel for supplying the gas or gas-liquid mixture of low pressure of the first cyclonic th separator, and the gas outlet of the second cyclone separator is connected to the outlet for the cleaned gas of the first cyclone separator.

The disadvantage of the prototype is that the liquid outlet from the second cyclone separator is connected to the purified gas, which leads to a deterioration in the liquid separation of the entire system. In addition, the described system assumes the use of both compact cyclone separators and a conventional tank separator, which leads to a complication of the entire separation system, an increase in the weight and size characteristics of the system and a corresponding increase in its cost.

The essence of the invention

The technical problem facing the invention is to provide a high efficiency of separation of liquid from gas with a minimum size and weight of the separation system.

The technical result of the claimed invention is to improve the efficiency of the selection of the liquid fraction from the gas fraction.

According to the invention, the technical problem is solved, and the technical result is achieved due to the fact that the in-line separator contains the main channel, which is a section of the pipeline with the first swirler, the first section of liquid separation, the section for taking off the gas-liquid flow, which are sequentially mounted inside it and are axially located. the first additional channel is docked perpendicular to the main channel, which is a section of the pipeline with a second swirler, a second section of liquid separation, a section of liquid collection and a container for collecting liquid, which are sequentially mounted inside it and axially located an ejector located in the main channel between the first swirler and the first liquid separation section, while a control valve can be installed in the second additional channel.

Brief Description of Drawings

FIG. 1 is a general diagram of an in-line separator.

The drawing indicates the following positions:

1 - main channel;

2 - the first swirler;

3 - the first section of liquid separation;

4 - section of the selection of the gas-liquid flow;

5 - the first additional channel;

6 - the second swirler;

7 - the second section of liquid separation;

8 - section for liquid sampling;

9 - capacity;

10 - second additional channel;

11 - ejector;

12 - control valve.

Implementation of the invention

The in-line separator consists of elements rigidly connected to each other by any known methods in the art, and is a main channel 1 and two additional channels 5 and 10, respectively. The main channel 1 is made in the form of a pipeline section, inside which the first swirler 2, the first liquid separation section 3 and the gas-liquid flow 4 selection section are sequentially and axially mounted. Also, the main channel 1 contains an ejector 11 located between the first swirler 2 and the gas-liquid flow separation section 4 ...

The first additional channel 5 is connected to the gas-liquid flow selection section 4 perpendicular to the main channel 1 by the method of docking (i.e., docked), which is a section of the pipeline with a second swirler 6 sequentially mounted inside it and axially located, a second liquid separation section 7, and a liquid selection section 8 and a container 9 for collecting the separated liquid.

The liquid sampling section 7 is connected by a second additional channel 10 with an ejector 11. In this case, a control valve 12 can be installed in the second additional channel.

The device works as follows:

The in-line separator works according to the following scheme. The gas flow with condensate droplets is directed to the main channel 1, where, passing through the first swirler 2, the flow acquires a tangential velocity (begins to rotate). The swirling flow enters the ejector 11, where it mixes with the recirculation gas flow. Further, the mixture of flows, which, after mixing, also has a tangential swirl of the flow, is directed to the first section of liquid separation 3, which is a cylindrical channel, in which, due to the action of centrifugal forces, liquid droplets move to the walls of the channel. At the outlet of the first liquid separation section 3, there is a gas-liquid flow selection section 4, where a two-phase boundary layer containing separated droplets and a small amount of gas is taken from the walls of the liquid separation section. From the central axial part of section 4, cleaned gas is taken (outlet flow). A two-phase flow (two-phase boundary layer) is withdrawn from the main channel 1 and directed to the first additional channel 5, in which the flow swirls in the second swirler 6, then in the swirling flow in the second section of liquid separation 7, drops are separated and a central paraxial a core consisting of pure gas and a two-phase boundary layer on the walls of section 7, containing all the separated liquid. In the section for sampling the liquid 8, a gas with a low liquid content is taken, which, through the second additional channel 10, enters the ejector 11 as a low-pressure flow. Liquid is also taken from section 8, which flows into container 9.

The first and second swirlers are stationary elements that can be made in the form of a central body with blades mounted on it (similar to the presented swirler, [1]).

The ejector 11, installed between the first swirler 2 and the first liquid separation section 3, is made according to the classic ejector scheme. In it, the flow swirled in the first swirler 2 is accelerated in the nozzle, due to which a vacuum is created at the nozzle exit. A low-pressure gas flow with a small liquid content is supplied to the zone of this vacuum through the second additional channel 10. The mixing of these streams occurs already in the channel of the first liquid separation section 3. In this case, the channel of the first liquid separation section 3 can be either conical converging, conical expanding, or cylindrical. The configuration of the channel of the liquid separation section 3 depends on the specific parameters of the inlet stream, in particular on the liquid content in the inlet stream and the allowable pressure drop across the in-line separator. For low pressure drop across the in-line separator and low liquid content, a cylindrical channel is preferred. The selection of the geometric parameters of the ejector can be carried out in accordance with the calculation method presented in the book "Collection of research papers", BNI TsAGI, 1961, pp. 332-336 [4]. With a high liquid content - an expanding channel, because in this case, the thickness of the two-phase boundary layer on the walls of the section increases; accordingly, the expansion of the channel compensates for the increase in the thickness of the boundary layer. The degree of expansion of the channel, respectively, can be estimated by calculating a two-phase boundary layer according to the method presented, for example, in the software package designed for calculating two-phase flows ANSYS CFX. With a large pressure drop across the in-line separator - a narrowing channel, because in this case, the efficiency of the ejector increases (see [4]).

The installation of a control valve in the second additional channel 10 makes it possible to regulate the flow rate of gas taken from the liquid sampling section 8, and, thus, to ensure the optimal operating mode of this section.

By creating a high swirling flow rate in the gas-liquid flow separation sections 3 and the liquid separation section 7, the described in-line separator allows a high degree of separation of even submicron liquid droplets to be ensured. As shown by the computational modeling of the gas-dynamic channel of the in-line separator at flow swirling velocities of 150 m / s, the in-line separator provides separation of 90% of droplets with a size of 0.3 μm. This figure is unattainable for separators currently used in the oil and gas industry, and which can provide separation of droplets no larger than 5 microns. This fact was confirmed in the course of instrumental measurements of droplet entrainment at the outlet from the presented in-line separator.

At the same time, the separator is mounted as an element of the pipeline, which significantly reduces the capital costs of its installation.

Claims (2)

1. In-tube separator containing the main channel 1, which is a section of the pipeline with the first swirler 2, the first section of the liquid separation 3, the section for the selection of the gas-liquid flow 4, and the section for the selection of the gas-liquid flow 4 perpendicular to the main channel, which are sequentially mounted inside it and axially located the first additional channel 5, which is a section of the pipeline with a second swirler 6, a second section of liquid separation 7, a section of a liquid withdrawal 8 and a container 9, which are sequentially mounted inside it and axially located, located in the main channel 1 between the first swirler 2 and the first liquid separation section 3. 2. An in-line separator according to claim 1, characterized in that a control valve 12 is installed in the second additional channel 10.

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