RU2389908C1 - Gas ejector - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: ejector is designed for gas and gas condensate field preparing at assemblies of low temperature gas separation with ejectors for gas utilisation and degassing of condensate. The gas ejector consists of a case with branches for high pressure, low pressure and mixed flow of gas. It also consists of a nozzle and of a mixing chamber coaxially arranged in the case; a bushing of a diffuser adjoins the mixing chamber. Also the branch of low pressure gas is conjugated with the mixing chamber via a narrowing circular cavity. An output section of the cavity of low pressure gas is of a toroid shape. A start section of the chamber wall has a circular thermo-insulating interlayer. Position of the mixing chamber in the case is fixed by means of the diffuser bushing adjacent to a collar of the case.

EFFECT: reduced metal consumption for fabrication of gas ejector and increased reliability of operation under modes of hydrate formation.

2 cl, 3 dwg

Description

The invention relates to the oil and gas industry and can be used for field preparation of gas and gas condensate in gas condensate or oil and gas condensate fields as part of plants using a low-temperature condensation (separation) method for drying gas by moisture and heavy hydrocarbons and a method of stepwise degassing of condensate for its partial stabilization, including ejectors for gas degassing utilization. Gas ejectors are known in which the pressure of a low-pressure (LH) gas, degassing gas is increased by mixing this stream with a stream of high-pressure (HL) gas at the inlet to the low-temperature separator of the field gas treatment unit. Gas ejectors are usually performed according to schemes with an axial or radial supply of gas to the HV housing, with a radial supply of HH gas and an axial exit of the gas mixture from the housing. [Russian Patent No. 2151920, Cl. F04F 5 | 14, publ. 2000].

Known gas ejectors have the following disadvantages:

- high metal consumption due to the use, at high overpressures of HV and LV media, normalized flange connectors of the housing and connecting pipes,

- lack of reliability in hydrate-forming modes, especially in the presence of a positive temperature difference between LV and HF flows.

The closest prototype of the present invention is an ejector of the type EG-9 of VNIIGAZ LLC, consisting of a body with nozzles of a high-pressure, low-pressure and gas mixture and coaxially placed in the nozzle body, a mixing chamber with an adjacent diffuser sleeve, and the low-pressure gas pipe is interfaced with the mixing chamber through a tapering annular cavity. [Tsarev I.N., Sidor P.G. Instruction manual for ejectors. VNIIGAZ, M., 1982, 27 pp.].

For production gas processing lines with a throughput of 5 million nm ³ / day, the mass of the EG-9 ejector is more than 700 kg, which makes it difficult to maintain it outside the stationary load-lifting devices.

The technical task of the proposed device is to reduce the metal consumption of the gas ejector and increase its reliability in hydrate-forming modes.

This object is achieved in that the gas ejector comprises a housing with nozzles of high pressure, low pressure and gas mixtures and a nozzle coaxially placed in the housing, a mixing chamber with an adjacent diffuser sleeve, the low pressure gas connecting to the mixing chamber through a tapering annular cavity, while the output the portion of the low-pressure gas cavity has a toroidal shape, the initial portion of the wall of the mixing chamber is made with an annular heat-insulating layer, and the position of the mixing chamber in the housing It is fixed by means of the housing adjacent to the collar of the diffuser sleeve.

In addition, the fastening of the nozzles to the housing can be performed using union nuts.

The proposed device can be implemented in the construction of a gas ejector, shown in figure 1. Mounting the nozzles to the housing, place I, Fig. 1, shown in Fig. 2. A longitudinal section of the initial portion of the wall of the mixing chamber is shown in FIG. 3.

The gas ejector comprises a cylindrical housing 1, FIG. 1, with nozzles 2 and 3 connected to it for supplying HV and LV gas, respectively, and a branch pipe for discharging the gas mixture 4. The nozzles are fixed to the housing using threaded union nuts 5, 6 with a seal joints rings 7, Fig.2.

A removable nozzle body 8 with a conical shape nozzle 9, as well as a cylindrical mixing chamber 10 with a conical diffuser 11, are coaxially aligned in the internal cavity of the housing, along with the gas, and the position of the mixing chamber in the housing relative to the annular flange of housing 12 is fixed using a flange sleeve of the diffuser 13 and studs 14.

The initial section of the mixing chamber adjacent to the annular cavity of the NN gas supply 15 is made with an annular heat-insulating layer 16 formed by double walls 17, 18 of the mixing chamber, FIG. 3. The mating surfaces of the nozzle body, nozzle, and mixing chamber form a toroidal channel 19 narrowing toward the mixing chamber to supply LH gas to the mixing chamber.

The device operates as follows. Ejecting high-pressure gas through the pipe 2 is fed into the nozzle 9, where the static pressure of the gas is converted into a high-pressure head with decreasing gas temperature. Ejected NN gas through the pipe 3 and through the annular cavity 15, 19 enters the mixing chamber 10 and the diffuser 11, where the flows interact and their braking. In this case, the pressure of the gas mixture increases. The gas mixture is discharged through pipe 4.

The toroidal shape of the channel 19, the mounting of the mixing chamber in the housing 1 with the sleeve of the diffuser 13 relative to the flange of the housing 12 and the fastening of the nozzles 2, 3, 4 to the housing using the union nuts 5, 6 improve the overall and weight characteristics of the device. For the conditions under consideration, the mass of the gas ejector is reduced by 6 times compared with the prototype.

The implementation of the initial section of the wall of the mixing chamber with an annular heat-insulating gas layer 16 increases the temperature of the wall of the mixing chamber from the side of the LH gas supply chamber, which reduces the likelihood of deposition of crystalline hydrates and ice on the wall and increases the reliability of the device.

The device’s operability was tested at the installation of integrated gas preparation for transport of the North Urengoy gas condensate field. Typical operating parameters of a gas ejector are given in the table.

Table
Operation parameters of a gas ejector at the Severo-Urengeyskoye field No. Parameter Value one High-pressure gas flow, thousand nm ³ / h 108 2 High-pressure gas pressure, MPa 8.9 3 High-pressure gas temperature, ° С minus 12 four Consumption of low-pressure gas, thousand nm ³ / h 7.0 5 Low-pressure gas pressure, MPa 2.1 6 Low-pressure gas temperature, ° С 0 7 The pressure of the gas mixture at the outlet, MPa 5,4 8 The temperature of the gas mixture at the outlet, ° C minus 31 9 The degree of compression of low-pressure gas 2.5 10 The coefficient of ejection,% 6.5 eleven The density of the HV gas under standard conditions, at 0.1013 MPa and 20 ° C 0.735

Claims (2)

1. A gas ejector comprising a housing with nozzles of high-pressure, low-pressure and gas mixtures, and a nozzle coaxially placed in the housing, a mixing chamber with an adjacent diffuser sleeve, the low-pressure gas nozzle being connected to the mixing chamber through a tapering annular cavity, characterized in that the outlet the portion of the low-pressure gas cavity has a toroidal shape, the initial portion of the wall of the mixing chamber is made with an annular heat-insulating layer, and the position of the mixing chamber in the housing is fixed with rilegayuschey the collar of the diffuser housing sleeve. 2. The ejector according to claim 1, characterized in that the mounting of the nozzles to the housing is made using union nuts.

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