Water-stripping integrated device for sulfur-containing gas field produced water

Abstract

The utility model discloses a sulfur-containing gas field produced water gas stripping integrated device which comprises a gas field water pump and a gas stripping tower which are connected with each other, a water inlet which is used for introducing gas field gas and is connected with an outlet of the gas field water pump is arranged at the upper part of the gas stripping tower, and a gas stripping nitrogen gas incoming line pipe which is connected with an air nitrogen station system is arranged at the lower part of the gas stripping tower; a gas stripping gas outlet pipeline connected with a purification station sulfur recovery unit is arranged at the top of the gas stripping tower, a gas field water output pipeline connected with a sewage treatment device is arranged at the bottom of the gas stripping tower, and the underground gas field water tank introduces gas field water from the separator through a gas field water inlet pipeline; a first outlet in the top of the underground gas field water tank is connected with an inlet of the gas field water pump through an acid water pipe, and a flash evaporation mechanism is arranged in the underground gas field water tank and connected with a second outlet of the underground gas field water tank and a gas stripping gas outlet pipeline. The device has the advantages of good desulfurization effect, factory prefabrication and convenience in site construction, and can be widely applied to the technical field of desulfurization.

Description

Technical Field

[0001] The utility model relates to desulfurization technology, in particular to an integrated device for stripping water produced from a sulfur-containing gas field. Background Technique

[0002] High-sulfur gas reservoirs are common gas reservoirs in the Sichuan-Chongqing region. With the development of high-sulfur gas reservoirs in the Changxing Formation bioherm, the fracturing fluid, condensate water, and gas field water (formation water) existing in such gas reservoirs all contain relatively high levels of sulfides. To ensure the smooth production of such gas reservoirs and meet the requirements for external discharge of water quality, an integrated device and method for stripping water produced from a sulfur-containing gas field are specifically developed.

[0003] At present, there are many methods for treating sulfur-containing sewage, such as chemical reagent oxidation method, chemical precipitation method, stripping method, and biochemical method, etc. 1) The chemical reagent oxidation method removes sulfides by adding chlorine, ozone, potassium permanganate, hydrogen peroxide, etc. This method is suitable for treating sewage with low sulfur content. When the sulfur content in the sewage is high, the treatment cost is high, and the strong oxidants added are likely to cause corrosion of pipelines and equipment. 2) The chemical precipitation method is to add ferrous or iron salts, etc. to the wastewater to form insoluble substances for removal. However, when the sulfur content in the sewage is high, the system produces a large amount of sludge and the treatment cost is high. 3) The stripping method is to make the stripping gas contact countercurrently with the gas field water in the stripping tower to reduce the partial pressure of H 2 S in the stripping tower and accelerate the desorption of H 2 S in the sewage so as to achieve the purpose of desulfurization. 4) The biochemical method is generally used to treat sulfur-containing wastewater with a mass concentration of sulfides less than 50 mg / L.

[0004] At present, the stripping method is generally used for high-sulfur gas field water. There are problems with the current stripping method: 1) The gas field water lift pump has a constant flow rate adjustment and cannot adjust the water flow rate into the stripping tower; 2) There is no filter at the front end of the stripping tower, resulting in blockage of the stripping tower filter element and affecting the filtration efficiency; 3) The stripping equipment includes devices such as filters, stripping water pumps, and stripping towers, etc., which are scattered, and the on-site construction workload is relatively large, etc. Content of the Utility Model

[0005] The purpose of the utility model is to overcome the deficiencies of the above background technique and provide an integrated device for stripping water produced from a sulfur-containing gas field, which has the advantages of good desulfurization effect, factory prefabrication, and convenience for on-site construction.

[0006] An integrated stripping device for produced water in a sulfur-containing gas field provided by the utility model comprises a gas field water pump and a stripping tower which are connected. The upper part of the stripping tower is provided with a water inlet for introducing gas field gas and connected to the outlet of the gas field water pump. The lower part of the stripping tower is provided with a gas inlet pipeline for stripping nitrogen gas connected to the air separation unit system. The top of the stripping tower is provided with a stripping gas outlet pipeline connected to the sulfur recovery unit of the purification station. The bottom of the stripping tower is provided with a gas field water external transmission pipeline connected to the sewage treatment device. It also includes an underground gas field water tank for introducing gas field water through a gas field water inlet pipeline from a separator. The first outlet at the top of the underground gas field water tank is connected to the inlet of the gas field water pump through an acid water pipe. A flash evaporation mechanism is arranged in the underground gas field water tank. The flash evaporation mechanism is connected to the second outlet of the underground gas field water tank and is connected to the stripping gas outlet pipeline.

[0007] In the above technical solution, an adjustable flow valve is arranged in the gas field water pump.

[0008] In the above technical solution, a gas field water filter with an inlet connected to its outlet is arranged at the outlet of the gas field water pump. The outlet of the gas field water filter is connected to the water inlet for introducing gas field gas at the upper part of the stripping tower.

[0009] In the above technical solution, the bottom of the stripping tower is provided with a gas field water external transmission pipeline connected to the sewage treatment device.

[0010] In the above technical solution, the bottom of the stripping tower is provided with a return water pipeline connected to the underground gas field water tank. The bottoms of the gas field water pump and the gas field water filter are connected to the underground gas field water tank through the return water pipeline.

[0011] In the above technical solution, a regulating valve is arranged at the second outlet of the underground gas field water tank. A regulating valve is arranged at the top of the stripping tower and is connected to the stripping gas outlet pipeline. A regulating valve is arranged on the gas field water external transmission pipeline at the bottom of the stripping tower.

[0012] In the above technical solution, an electromagnetic flowmeter is arranged between the outlet of the gas field water filter and the water inlet at the upper part of the stripping tower. An electromagnetic flowmeter is arranged on the gas field water external transmission pipeline at the bottom of the stripping tower.

[0013] In the above technical solution, an emergency cut-off valve is arranged on the gas field water external transmission pipeline at the bottom of the stripping tower.

[0014] In the above technical solution, a drain pipe connected to the low-pressure venting and liquid separation tank of the purification station is arranged at the second outlet of the underground gas field water tank.

[0015] In the above technical solution, the gas field water pump, the gas field water filter and the stripping tower are integrally of a skid-mounted structure.

[0016] The integrated stripping device for produced water in a sulfur-containing gas field of the utility model has the following beneficial effects:

[0017] The produced water from the sulfur gas field is first flashed in the underground gas field water tank to remove part of hydrogen sulfide. The impurities settle at the bottom of the tank. The remaining part of the sulfur-containing produced water from the gas field is lifted by a pump to a filter separator for filtration and separation. The gas field water pump can adjust the gas field water volume and then enters the stripping tower for stripping. The stripping gas and the gas field water contact countercurrently in the stripping tower to reduce the partial pressure of H 2 S in the stripping tower and remove the H 2 S gas in the sulfur-containing produced water from the gas field. The technical solution of the present utility model has a simple structure. The gas field water pump, the gas field water filter, and the stripping tower are integrated into a skid, which is convenient for hoisting and reduces the on-site workload. The process is simple and convenient for removing hydrogen sulfide gas in the sulfur-containing produced water from the gas field. Brief Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the stripping integrated device for the produced water from the sulfur-containing gas field of the present utility model. Detailed Embodiments

[0019] The present utility model will be further described in detail below in conjunction with the drawings and embodiments, but the embodiments should not be construed as limiting the present utility model.

[0020] As Figure 1 shown, an integrated stripping device for the produced water from a sulfur-containing gas field of the present utility model includes an underground gas field water tank 1, a gas field water pump 2, a gas field water filter 3, an electromagnetic flowmeter 4, a stripping tower 5, an emergency cut-off valve 6, a regulating valve 7, a gas field water inlet pipeline 8, a return water pipeline 9, a safety valve group 10, and an inlet and outlet pipeline. The gas field water outlet of the underground gas field water tank 1 is communicated with the inlet of the gas field water pump 2. The outlet of the gas field water pump 2 is communicated with the inlet of the gas field water filter 3. The outlet of the gas field water filter 3 is communicated with the upper water inlet of the stripping tower 5. The outlet of the stripping tower 5 is provided with an electromagnetic flowmeter 4, an emergency cut-off valve 6 and is communicated with the gas field water external transmission pipeline 13. The flash gas outlet of the underground gas field water tank 1 is communicated with the stripping gas outlet pipeline 11. The acid water pipelines of the gas field water pump 2, the gas field water filter 3, and the stripping tower 5 are communicated with the return water pipeline 9 of the underground gas field water tank 1. The outlet end of the vent valve group of the underground gas field water tank 1 is communicated with the outlet end of the vent valve group of the stripping tower 5.

[0021] Preferably, the gas field water pump 2 is provided with a flow regulating valve;

[0022] Preferably, the liquid level gauge of the underground gas field water tank 1 is communicated with the regulating valve 7 of the stripping tower to maintain the liquid level of the water tank;

[0023] Preferably, a control skid base is provided, as well as a combustible gas detection device, a video monitoring device, and a control cabinet installed on the control skid base; the control skid base is detachably connected to the main skid base; the combustible gas detection device, the monitoring device, and the control cabinet are all connected to the power distribution cabinet; the monitoring area of the monitoring device covers the entire main skid base; the monitoring device, the safety alarm device, and each pneumatic emergency cut-off valve are respectively connected to the control cabinet, and the control cabinet obtains the monitoring information and controls the on-off of each pipeline by controlling the opening of the pneumatic emergency cut-off valve. The main skid base and the control skid base have the same structure, and each respectively includes a plurality of main cross beams, a plurality of main longitudinal beams, a plurality of secondary cross beams, a plurality of secondary longitudinal beams, and steel plates. The plurality of main cross beams, secondary cross beams, main longitudinal beams, and secondary longitudinal beams are arranged at intervals and connected to form a framework, and the steel plates are installed on the upper part of the framework.

[0024] The utility model is generally used for the produced water desulfurization part of high-sulfur gas fields. After the produced water is stripped by this device, it reaches the water quality reinjection index, ensuring the successful production of high-sulfur gas wells. The specific principle is as follows:

[0025] I. Flashing of the underground gas field water tank 1

[0026] The gas field water enters the underground gas field water tank 1, and part of the H2S gas is separated by flashing. The impurities in the gas field water settle at the bottom of the water tank to avoid clogging the filter screen in the subsequent process. The gas field water then goes to the gas field water pump 2.

[0027] II. Lifting by the gas field water pump 2

[0028] When the liquid level in the underground gas field water tank 1 reaches the high liquid level alarm, the gas field water pump 2 is started through the interlock signal, and the gas field water is lifted to 0.4 MPa.g and then sent to the gas field water filter 3.

[0029] III. Filtration by the gas field water filter 3

[0030] The stripped water from the gas field water pump 2 is filtered by the gas field water filter 3. The filtration efficiency of the filter is 99%, and the filtration diameter is ≥10 μm, ensuring that no impurities enter the stripping tower 5 and avoiding clogging of the filter element and equipment. An electromagnetic flowmeter 4 is installed at the outlet of the gas field water filter 3 to measure the water volume entering the stripping tower 5.

[0031] IV. Stripping in the stripping tower 5

[0032] The sulfur-containing gas field water enters the stripping tower 5 and flows from top to bottom, countercurrently contacting the stripping gas (coming from the nitrogen system) flowing from bottom to top in the tower, removing the H2S gas in the sulfur-containing sewage. The stripping gas returns from the top of the stripping tower 5 to the sulfur recovery unit for further treatment. 2 S gas. The stripping gas returns from the top of the stripping tower 5 to the sulfur recovery unit for further treatment.

[0033] In a further embodiment of the present utility model, it includes an underground gas field water tank 1, a stripping tower 5, a gas field water pump 2, a gas field water filter 3, and a sulfur-containing gas field acid water main pipe; the sulfur-containing gas field water from the liquid phase of the separator and the gas field water enter the inlet of the underground gas field water tank 1, the gas field water at the outlet of the underground gas field water tank 1 is connected to the inlet of the gas field water pump 2, the flash steam of the underground gas field water tank 1 is connected to the outlet pipeline of the stripping tower 5, the outlet of the gas field water pump 2 is connected to the inlet of the gas field water filter 3, the outlet of the gas field water filter 3 is connected to the inlet of the stripping tower 5, the treated sulfur-containing stripping gas is sent to the sulfur recovery unit, the desulfurized gas field water is discharged externally, and the return water pipeline 9 is connected to the inlet of the underground gas field water tank 1 through the acid water main pipe.

[0034] A pressure regulating valve 7 is provided at the flash steam outlet of the underground gas field water tank 1 and is interlocked with the pressure of the gas field water tank. When the pressure exceeds the set value, the pressure regulating valve 7 operates, and the flash steam goes to the stripping gas outlet pipe 11 at the top of the stripping tower 5.

[0035] The purge pipeline of the underground gas field water tank 1 is provided with holes symmetrically inclined downward at 45°, and they are evenly arranged at intervals of 300 mm along the bottom purge pipeline.

[0036] During normal production, the valve for the acid water main pipe to enter the underground gas field water tank 1 is normally closed. When it is necessary to collect the non-pressure acid water during shutdown, after opening the manual vent valve to relieve pressure first, then open this valve to collect the non-pressure acid water.

[0037] A Y-type filter is installed at the front end of the gas field water pump 2 to filter impurities at the inlet and ensure the normal operation of the gas field water pump 2.

[0038] An electromagnetic flowmeter 4 is provided at the rear end of the gas field water filter 3, which can accurately measure the flow rate of the produced water entering the gas field water stripping tower 5.

[0039] Safety pipelines are provided at the tops of the underground gas field water tank 1, the gas field water filter 3, and the stripping tower 5, and a safety valve group 10 is configured on these safety pipelines.

[0040] The stripping gas uses nitrogen, and a vortex flowmeter is set at the inlet, which is connected to the control of the regulating valve 7 at the inlet. The flow rate of the stripping gas can be adjusted by controlling the opening of the regulating valve 7.

[0041] An emergency cut-off valve 6 is provided at the gas field water outlet of the stripping tower 5 to ensure that the gas field water is not discharged externally in case of an accident.

[0042] An on-line pH value analyzer is provided at the gas field water outlet of the stripping tower 5, and it can analyze whether the hydrogen sulfide removal effect is satisfied through on-line data analysis. When the H 2 S content of the bottom gas field water is not qualified after treatment, it will be circulated into the underground gas field water tank 1 and the stripping process will be repeated. After the H 2 S content of the bottom gas field water is qualified after treatment, the regulating valve 7 is opened, and the opening of the regulating valve 7 is controlled by the liquid level in the tower. The qualified gas field water after detection enters the sewage system.

[0043] The liquid level signal of the liquid level gauge of the underground gas field water tank 1 is connected to the return water of the air stripping tower 5 to control the liquid level height of the underground gas field water tank 1.

[0044] Electromagnetic flowmeters 4 are provided at the inlet of the air stripping tower 5 where the gas field water filter 3 enters and at the gas field water outlet of the air stripping tower 5.

[0045] Vortex flowmeters and regulating valves 7 are provided on both the incoming gas pipeline and the outgoing gas pipeline for gas stripping of the gas field water.

[0046] Safety pipelines are provided at the tops of the underground gas field water tank 1, the gas field water filter 3, and the air stripping tower 5, and safety valve groups 10 are equipped on these safety pipelines.

[0047] The gas field water pump 2, the gas field water filter 3, and the air stripping tower 5 are integrally formed into a skid-mounted gas field water air stripping tower. The integral skid-mounted structure can achieve factory prefabrication, on-site modular construction, convenient hoisting and transportation, reduction of on-site operation volume and construction period.

[0048] The skid is equipped with an explosion-proof control cabinet. The control cabinet has a touch screen and can realize the PID parameter adjustment function, and can display or query the set value, fault alarm, and operating status. The control cabinet should be able to provide remote start and stop signals, hard-wired signals such as operating status signals, fault alarms, and emergency stops. At the same time, an instrument control junction box is set up to meet the requirements of remote control.

[0049] The present utility model also provides a produced water desulfurization process based on the sulfur-containing gas field produced water air stripping integrated device as described above. This process includes the following steps:

[0050] Step 1: The sulfur-containing gas field water separated by the gas-liquid separator goes to the underground gas field water tank 1, where it flashes to remove part of the H2S, and the flashed gas enters the outlet pipeline of the air stripping tower 5;

[0051] Step 2: When the liquid level in the underground gas field water tank 1 reaches the high liquid level alarm, the gas field water pump 2 is started, and the gas field water is lifted to 0.4 MPa.g;

[0052] Step 3: After being filtered by the gas field water filter 3, it enters the air stripping tower 5 for air stripping;

[0053] Step 4: The sulfur-containing gas field water enters the air stripping tower 5 and flows from top to bottom, countercurrently contacting the air stripping gas (coming from the nitrogen system) flowing from bottom to top in the tower to remove the H2S gas in the sulfur-containing sewage. The sour gas returns from the top of the air stripping tower 5 to the sulfur recovery unit for further treatment.

[0054] In Step 1, the regulating valve 7 is controlled by the liquid level of the underground gas field water tank 1 to stabilize the liquid level in the underground gas field water tank 1.

[0055] In Step 4, when the gas field water device starts operation, close the regulating valve 7, and all the gas field water flows back to the underground gas field water tank 1 until the hydrogen sulfide content in the gas field water at the bottom of the tower is lower than 10 ppm.

[0056] In Step 4, the sulfur-containing maintenance sewage in this device is collected through the acid water main pipe to the underground gas field water tank 1 for treatment. When the underground gas field water tank 1 collects the maintenance sewage in the device, first open the bypass line of the safety valve to empty the gas in the tank, then open the valve of the acid water main pipe leading to the acid water tank. After emptying, introduce nitrogen to stabilize the pressure to 0.1 MPa, and then start the gas field water device to treat the gas field water.

[0057] The gas field water desulfurization skid-mounted equipment and process of the present utility model efficiently solve the problem of removing H2S from the produced water of high-sulfur gas fields, are convenient to operate, have good performance, and the skid-mounted equipment reduces the on-site operation volume, achieving good economic benefits.

[0058] Obviously, those skilled in the art can make various modifications and variations to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and its equivalent technologies, the present utility model also intends to include these modifications and variations.

[0059] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. An integrated device for stripping produced water from a sulfur-containing gas field, comprising a connected gas field water pump (2) and a stripping tower (5), wherein the upper portion of the stripping tower (5) is provided with a water inlet connected to the outlet of the gas field water pump (2) for introducing gas field gas, the lower portion of the stripping tower (5) is provided with a stripping nitrogen gas supply line (12) connected to an air nitrogen station system, the top of the stripping tower (5) is provided with a stripping gas outlet pipeline (11) connected to a sulfur recovery unit of a purification station, and the bottom of the stripping tower (5) is provided with a gas field water transmission pipeline (13) connected to a sewage treatment device, characterized in that: It also comprises an underground gas field water tank (1) for introducing gas field water from the separator through a gas field water inlet pipeline (8), a first outlet at the top of the underground gas field water tank (1) being connected to an inlet of a gas field water pump (2) through an acid water pipe, a flash evaporation mechanism being provided in the underground gas field water tank (1), the flash evaporation mechanism being connected to a second outlet of the underground gas field water tank (1) and connected to a gas lift gas outlet pipeline (11).

2. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 1, characterized in that: The gas field water pump (2) is provided with an adjustable flow valve.

3. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 2, characterized in that: The outlet of the gas field water pump (2) is provided with a gas field water filter (3) whose inlet is connected thereto, and the outlet of the gas field water filter (3) is connected to a water inlet at the top of the gas stripping tower (5) for introducing gas field gas.

4. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 3, characterized in that: A return water pipeline (9) connected to an underground gas field water tank (1) is provided at the bottom of the gas stripping tower (5), and the bottoms of the gas field water pump (2) and the gas field water filter (3) are connected to the underground gas field water tank (1) via the return water pipeline (9).

5. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 4, characterized in that: The second outlet of the underground gas field water tank (1) is provided with a regulating valve (7), the top of the gas stripping tower (5) is provided with a regulating valve (7) connected to a gas stripping gas outlet pipeline (11), and the gas field water export pipeline (13) at the bottom of the gas stripping tower (5) is provided with a regulating valve (7).

6. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 5, characterized in that: An electromagnetic flowmeter (4) is provided between the outlet of the gas field water filter (3) and the water inlet at the top of the gas stripping tower (5), and an electromagnetic flowmeter (4) is provided on the gas field water transmission pipeline (13) at the bottom of the gas stripping tower (5).

7. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 6, characterized in that: An emergency shut-off valve (6) is provided on the gas field water transmission pipeline (13) at the bottom of the gas stripping tower (5).

8. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 7, characterized in that: The second outlet of the underground gas field water tank (1) is provided with a drainage pipe connected to the low-pressure venting and liquid separation tank of the purification station.

9. The integrated device for gas stripping produced water from a sulfur-containing gas field according to claim 8, characterized in that: The gas field water pump (2), the gas field water filter (3) and the gas stripping tower (5) are overall in a skid-type structure.

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