RU179040U1 - Installation for preparing pulsed gas for pneumatic systems of shut-off and control devices of gas mains - Google Patents

Abstract

A pulsed gas preparation unit for pneumatic systems of shut-off and control devices of gas pipelines includes a gas purification system mounted on a single frame, a regeneration system with two adsorber filled with a zeolite absorber, with external electric heating and connected to a vacuum pump, while the regeneration system contains a gas pressure sensor and a metering unit humidity (dew point) of the pulsed gas, and each adsorber is made with an inner diameter of 0.18 to 0.30 m and has a volume of from 0.025 to 0.050 m.

Description

The utility model relates to the transportation of natural gas through pipelines, and in particular to devices for the preparation of pulsed gas used in pneumatic actuators of shut-off and control devices at pumping and booster gas compressor stations and other objects of the gas industry.

It is known that the specifics of operation of shut-off and control valves at gas industry facilities requires especially thorough cleaning of moisture and mechanical particles of natural gas taken from the gas pipeline, which is sent to actuators with a pneumatic or pneumo-hydraulic control system of shut-off and control devices.

The main parameters of pulsed gas installations are the throughput (or flow rate) of pulsed natural gas, operating pressure, the degree of drying or moisture content of the dried gas, as measured by the dew point temperature. An impulse gas preparation unit must ensure continuous drying of natural gas, operate at various pressures without loss of productivity (throughput) and drying quality, but it is necessary that the unit has compact overall dimensions (first of all, minimum height) to ensure installation and maintenance of the unit in a transportable container.

A known installation for the preparation of pulsed gas for pneumatic systems of shut-off and control devices of main gas pipelines, including a piping system, electrical equipment, an automatic control unit and a gas drying and purification unit connected to a natural gas transport pipeline, contains a water-oil separator, an intermediate carbon filter, and a regeneration system with at least at least two regenerable adsorbers having external electrical heating, end filter and shut-off ball-controlled electrically fittings in which a pulse gas humidity measuring unit (dew point) connected to the automatic control unit is installed (RF patent No. 74188, IPC F17D 1/00, publ. 2008).

The known installation for the preparation of pulsed gas contains a node for measuring the humidity (dew point) of the pulsed gas, and the regeneration can adapt to the actual conditions of moisture saturation of the adsorbent, however, the disadvantages of the known installation include the fact that the size of the adsorber and the volume of the adsorbent may be insufficient to provide the necessary moisture content (points dew) and productivity (throughput) when changing the operating mode, for example, reducing the gas pressure at which the moisture content increases and increases Volumetric flow rate.

A known installation for the preparation of pulsed gas for pneumatic systems of shut-off and control devices of main gas pipelines, including a piping system, an electrical equipment, an automatic control unit, a gas purification system, a regeneration system with at least two regenerable adsorbers having external electrical heating, a moisture metering unit (points dew) of pulsed gas and shutoff valves, characterized in that the installation further comprises a gas pressure sensor in the regeneration system of the adsorbers and yes a gas pressure difference sensor at the inlet and outlet of the unit connected to the automatic control unit (RF patent No. 138290, IPC F17D 1/00, publ. 2014).

A disadvantage of the known installation is that the regeneration in the known installation is carried out at excess or atmospheric pressure, which requires a high temperature, a long heating time, and leads to large losses of natural gas for purging the adsorber under pressure.

In the case of applying vacuum to zeolite adsorbents, water desorption is achieved at a threshold temperature of regeneration of 150 ° C (N. Keltsev, Fundamentals of Adsorption Technology, Moscow: Chemistry, 1976, p. 200), which is lower than the temperature of zeolite adsorbent regeneration at atmospheric or overpressure, for example, in a known installation for the recovery of zeolite from water vapor, the adsorber was heated by electric current to 340-360 ° C (N. Keltsev, Fundamentals of Adsorption Technology, Moscow: Chemistry, 1976, p. 201).

During the operation of the natural gas dehydration unit, the working pressure is of particular importance, since when the working pressure is reduced, the moisture content of natural gas increases and the volume flow of natural gas increases, which means the gas travels through the zeolite adsorbent layer, which worsens the working conditions and reduces the time of adsorbent saturation with moisture .

In accordance with paragraph 6.3.3.2 STO Gazprom 2-3.5-230-2008 (Typical technical requirements for gas treatment devices at compressor stations / OAO Gazprom. - M .: Gazprom, 2008), the gas capacity of the dehydration unit is from 300 st .m ³ / h to 500 stm ³ / h, while the pressure at the inlet to the installation can vary and range from 11.8 to 3.5 MPa.

At a pressure of 9.8 MPa, the moisture content of the gas is 0.25 g / m ³ , and at a pressure of 3.5 MPa, the moisture content of the gas is 0.6 g / m ³ (Zhdanova N.V., Khalif A.L. Drying of hydrocarbon gases, M: Chemistry, 1984, Figure 1.1, p. 8).

To ensure a productivity of 500 stm ³ / h at a pressure of 9.8 MPa, it is necessary to remove 125 g of water per hour from the gas, and at a pressure of 3.5 MPa, due to the increase in moisture content, 300 g of water per hour must be removed from the gas, thus the adsorbent volume and the cross-sectional diameter must be calculated and have a margin to enable low-pressure operation.

The maximum gas velocity through the adsorbent υ _s at a pressure of 9.8 MPa should not be higher than 12 m / min, the maximum gas velocity through the adsorbent υ _s at a pressure of 3.5 MPa should not be higher than 16 m / min. Given the need to reduce the pressure drop across the adsorber, the speed should be no more than 10 m / min (John Carroll, Natural Gas Hydrates, translated from English, Reference Manual, Moscow: Premium Engineering CJSC, 2007, p. 155 -157).

The volumetric flow rate of pulsed gas through an adsorber at a pressure of 9.8 MPa is approximately Gact = 500 / (98 * 60) = 0.085 m ³ / min, the volumetric flow rate of pulsed gas through an adsorber at a pressure of 3.5 MPa is approximately Gact = 500 / (34 * 60) = 0.245 m ³ / min.

Therefore, the minimum diameter of the adsorber at a pressure of 9.8 MPa is d = sqrt (4Gact / 7πυ _s ) = sqrt (4 * 0,085 / 3,1415 * 10) = 0.10 m,

and the minimum diameter of the adsorber at a pressure of 3.5 MPa is d = sqrt (4Gact / πυ _s ) = sqrt (4 * 0.245 / 3.1415 * 10) = 0.18 m.

Therefore, under reduced pressure, an adsorber with a smaller diameter will not provide the required drying parameters. With a diameter of 0.18 to 0.30 m and an adsorbent volume of 0.018 to 0.050 m ³ , the required productivity (throughput) is ensured. With an increase in diameter, the pressure drop and the necessary height of the adsorber decrease, but with an increase in the adsorbent volume and above 0.050 m ³ (50 liters), the overall dimensions significantly increase and the cost of heating the adsorbent increases, which reduces the ease of use.

With a diameter of 0.18 to 0.30 m and an adsorber height of 0.7 to 2.0 m, the volume is from 0.025 to 0.050 m ³ , which provides the required performance (throughput) and at the same time economy and ease of use.

The objective of this utility model is to create a pulsed gas preparation unit for pneumatic actuators of shutoff and control valves of gas pumping stations of natural gas main pipelines, providing the required performance (throughput) and at the same time cost-effectiveness and ease of use.

The technical result achieved is an increase in the efficiency, economy, and reliability of the operation of pulse gas treatment plants for pneumatic drives of shut-off and control valves of gas pumping stations.

A pulsed gas preparation unit for pneumatic systems of shut-off and control devices of gas mains includes a gas purification system mounted on a single frame, a regeneration system with two adsorber filled with a zeolite absorber, with external electric heating and connected to a vacuum pump, while the regeneration system contains a gas pressure sensor and a metering unit humidity (dew point) of the pulsed gas, and each adsorber is made with an inner diameter of from 180 to 300 mm and has a volume of from 0.025 to 0.050 m ³ .

In FIG. 1 is a schematic diagram of a pulsed gas preparation plant; in FIG. 2 shows a setup for preparing pulsed gas on a frame, front view; in FIG. 3 - same, plan view.

The impulse gas preparation unit (see Figs. 1-3) contains a pipeline 1 connected at the inlet of the installation to the main gas pipeline, and at the outlet of the installation to consumers of natural gas.

The installation includes a hand-held ball valve 2, a water-oil separator 3, a preliminary filter 4, two adsorbers 5 and 6 connected in parallel, and an end filter 7 installed on the pipeline after electrically operated valves 8 and 9, respectively, in the direction of gas flow, connected in series to the pipeline inlet. Also, a manual gas sampling valve 10 is installed on the pipeline 1 before the gas is supplied to the oil and water separator 3. The oil and water separator 3 and the pre-filter 4 are connected through a non-return valve 11, an electrically operated valve 12 and a non-return valve 13 to the drain line, where periodic purging is performed. On the drainage line there is additionally a storage tank 14 for collecting a water-oil emulsion. The pre-filter 4 is in communication with adsorbers 5 and 6 through electrically operated valves 15 and 16, respectively. The adsorbers 5 and 6 are in communication with the capacity 14 through the solenoid valves 17 and 18, respectively, the solenoid valve 19, the vacuum pump 20 and the non-return valve 21. On the pipe 1 between the solenoid valve 19 and the vacuum pump 20, a pressure sensor for the regeneration system 22 is installed. The regeneration line is installed an electrically controlled valve 23 for relieving the operating pressure from the adsorbers 5 and 6 to the storage tank 14 before regenerating the corresponding adsorber.

For each adsorber 5 and 6, in order to provide protection against possible excess of the design pressure, two safety valves 24, 25 and 26, 27 are connected via adsorbers 5 and 6 through switching devices 28 and 29, respectively.

An electrically controlled valve 33 and a non-return valve 34 are sequentially installed on the pipeline 1 between the manual ball valve 2 and the manual ball valve 31. For emergency gas discharge from the system, an electrically controlled valve 35 is installed on the pipeline 1.

Between the filter end 7 and the manual ball valve 31 after the non-return valve 30 installed on the pipeline 1 before the gas supply to the consumer, a node for measuring the humidity (dew point) of the pulse gas 32 is installed.

The control of the impulse gas preparation unit is ensured in accordance with the given algorithm of the unit operation by means of a top-level control system providing control of electrically controlled valves 8, 9, 12, 15, 16, 17, 18, 19, 23, 33, 35 and receiving signals from the pressure sensor in the regeneration system 22 and the node for measuring the humidity of the pulsed gas 32, temperature and pressure sensors of the adsorbers 5 and 6.

All installation systems (see. Fig. 2 and 3) are placed on a single frame 36.

The installation works as follows.

Compressed natural gas under operating pressure from the main gas inlet from the pipeline 1 through a manual ball valve 2 enters the oil and water separator 3, where the gas is purified from large particles of moisture, oil and mechanical particles. From the oil-water separator 3, the gas enters the pre-filter 4 containing carbon fiber, in which the gas is cleaned of oil vapors that adversely affect the operation of the adsorbent in the adsorbers 5 and 6, as well as the operation of the pulse moisture measurement unit 32.

The oil-water emulsion separated in the oil-water separator 3 and the oil-water emulsion separated in the intermediate filter 4 are sent together to the storage tank 14 through the non-return valve 13 during periodic purges by opening the electrically operated valve 12. The non-return valve 11 prevents the oil-water emulsion from entering the oil-water separator 3 during the oil-water separator 3 .

Natural gas purified from drip moisture and oil enters one of the adsorbers 5 and 6, where the gas is dried to the specified parameters.

The adsorbers 5 and 6 operate alternately, one is running for drying, and the other is regenerated at this time, by opening (closing) the solenoid valves 8 (9) and 15 (16) and closing (opening) the solenoid valves 17 (18), while regeneration is much less than the running time for drying. During the passage of the gas through the adsorbing agent 5 or 6 operating for drying, the adsorbent in it is saturated with moisture, and the dried and purified gas enters the end filter 7.

After saturation of the adsorbent with moisture, the adsorbers 5 and 6 are switched over, and the adsorber 5 or 6 previously spent on drying is switched on for regeneration. The gas contained in the canister of the adsorber 5 or 6 immediately at the end of the drying mode is discharged by opening the electrically controlled valve 23, after which the cylinder of the regenerated adsorber 5 or 6 is heated to a predetermined temperature and the desorbed components are periodically pumped by the vacuum pump 20 into the drainage tank 14.

Each adsorber 5 and 6 is made with an inner diameter of from 180 mm to 300 mm and has a volume of from 0.025 to 0.050 m ³ .

The use of vacuum regeneration of adsorbers 5 and 6 with simultaneous heating provides the possibility of regeneration of the adsorbent with lower gas losses, at lower temperatures and, therefore, with lower energy consumption.

After the adsorber 5 or 6, the dried and purified gas enters the end filter 7, where the final cleaning of the gas from mechanical particles and oil takes place. Further, the gas through the non-return valve 30 is directed through the outlet of the pipeline 1 to the consumer of the pulse gas.

If the humidity of the pulsed gas supplied to consumers is higher than the set (control) setting, according to the readings of the humidity metering unit (dew point) of the pulsed gas 32 installed on the outlet pipe, the adsorbers 5 and 6 are switched.

The proposed installation is intended for the preparation of pulsed gas before its use for controlling pneumatic actuated valves and instrumentation of compressor stations of gas pipelines, gas distribution stations, underground gas storages and similar facilities.

The proposed pulsed gas preparation plant can efficiently and reliably operate under changing operating conditions (changing working pressure, long downtime, constant non-stop operation) in various climatic conditions, providing the necessary drying and purification of natural gas supplied to the pneumatic systems of gas industry facilities.

Claims (1)

A pulsed gas preparation installation for pneumatic systems of shut-off and control devices of gas pipelines, including a gas purification system located on a single frame, a regeneration system with two adsorber filled with a zeolite absorber, with external electrical heating and connected to a vacuum pump, while the regeneration system contains a gas pressure sensor and a unit measuring humidity (dew point) of a pulsed gas, characterized in that each adsorber is made with an inner diameter of 0.18 to 0.30 m and has a volume of from 0.025 about 0.050 m ^3.

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