Injecting decreasing recycling method for water produced in gas field

Abstract

The invention relates to an injecting decreasing recycling method for water produced in a gas filed. The method is characterized in that A / O / MBR-catalytic ozonation-efficient hardness removing and filtering-membrane distillation processes are carried out to effectively remove suspensions, organic matters, salt and ammonia nitrogen in wastewater, so that the problem of excessively high indexes suchas the suspensions, the organic matters, ammonia nitrogen and chlorides in injecting decreasing recycling process of the water produced in the gas field can be solved; the re-injecting volume of thewastewater is effectively decreased; in addition, the industrial low-temperature waste heat is utilized to realize the injecting decreasing recycling of the water reproduced in the gas field; and theobtained membrane distillation water is recycled for supplementing recycling water; and the concentrated water obtained in membrane distillation is re-injected.

Description

technical field

[0001] The invention relates to the field of industrial wastewater treatment, in particular to a method for reducing injection and recycling gas field produced water. In particular, it refers to the method of using A / O / MBR—ozone catalytic oxidation—high efficiency hard removal filtration—membrane distillation technology to treat gas field produced water for reuse. Background technique

[0002] With the development of social economy and the continuous improvement of people's living standards, the demand for energy is increasing day by day, and the amount of gas field exploitation is increasing year by year. In the development of gas fields, especially in the middle and late stages of gas field development, since formation water can invade gas reservoirs along faults and structural fractures, and enter the bottom of wells, the energy loss of gas reservoirs will increase, wellhead pressure will decrease, and water carrying capacity will deteriorate. As a result...

Examples

Embodiment 1

[0061] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7, total dissolved solids 10000mg / L, suspended solids 300mg / L, oil content 5mg / L, ammonia nitrogen 50mg / L, total hardness (CaCO 3 meter) 800mg / L, total alkalinity (CaCO 3 Total) 250mg / L, Na + 4000mg / L, Cl - 5000mg / L, SO 4 2- 800mg / L, COD 800mg / L.

[0062] The processing steps are as follows:

[0063] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of the anoxic section A is 4h, the total residence time of the aerobic O section and the MBR membrane pool is 27h, the sludge return rate is 300%, the sludge discharge volume is 1%, and the sludge concentration is 10g / L;

[0064] Under these conditions, the MBR membrane flux is controlled at 12L / m 2 h; COD of MBR product water is about 200mg / L, ammonia nitrogen is about 28mg / L;

[0065] Step 2, the MBR product water enters ...

Embodiment 2

[0073] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7.5, total dissolved solids 16000mg / L, suspended solids 700mg / L, oil content 10mg / L, ammonia nitrogen 120mg / L, total hardness (CaCO 3 meter) 1200mg / L, total alkalinity (CaCO 3 Total) 500mg / L, Na + 7000mg / L, Cl - 9000mg / L, SO 4 2- 1100mg / L, COD 1300mg / L.

[0074] The processing steps are as follows:

[0075] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of anoxic section A is 5h, the total residence time of aerobic O section and MBR membrane pool is 30h, the sludge return rate is 350%, the sludge discharge volume is 1.5%, and the sludge concentration is 11g / L;

[0076] Under these conditions, the MBR membrane flux is controlled at 11L / m 2 h; COD of MBR product water is about 280mg / L, ammonia nitrogen is about 65mg / L;

[0077] Step 2: Before the MBR product water ent...

Embodiment 3

[0085] The main water quality characteristics of gas field produced water are: influent pH 8, total dissolved solids 22000mg / L, suspended solids 1500mg / L, oil content 20mg / L, ammonia nitrogen 250mg / L, total hardness (CaCO 3 meter) 1800mg / L, total alkalinity (CaCO 3 Total) 750mg / L, Na + 10000mg / L, Cl - 12000mg / L, SO 4 2- 1500mg / L, COD 1500mg / L.

[0086] The processing steps are as follows:

[0087] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of the anoxic section A is 6h, the total residence time of the aerobic O section and the MBR membrane pool is 32h, the sludge return rate is 400%, the sludge discharge volume is 2%, and the sludge concentration is 12g / L;

[0088] Under these conditions, the MBR membrane flux is controlled at 12L / m 2 h; COD of MBR product water is about 360mg / L, ammonia nitrogen is about 110mg / L;

[0089] Step 2, before the MBR product water enters t...

technical field

[0001] The invention relates to the field of industrial wastewater treatment, in particular to a method for reducing injection and recycling gas field produced water. In particular, it refers to the method of using A / O / MBR—ozone catalytic oxidation—high efficiency hard removal filtration—membrane distillation technology to treat gas field produced water for reuse. Background technique

[0002] With the development of social economy and the continuous improvement of people's living standards, the demand for energy is increasing day by day, and the amount of gas field exploitation is increasing year by year. In the development of gas fields, especially in the middle and late stages of gas field development, since formation water can invade gas reservoirs along faults and structural fractures, and enter the bottom of wells, the energy loss of gas reservoirs will increase, wellhead pressure will decrease, and water carrying capacity will deteriorate. As a result...

Examples

Embodiment 1

[0061] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7, total dissolved solids 10000mg / L, suspended solids 300mg / L, oil content 5mg / L, ammonia nitrogen 50mg / L, total hardness (CaCO 3 meter) 800mg / L, total alkalinity (CaCO 3 Total) 250mg / L, Na + 4000mg / L, Cl - 5000mg / L, SO 4 2- 800mg / L, COD 800mg / L.

[0062] The processing steps are as follows:

[0063] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of the anoxic section A is 4h, the total residence time of the aerobic O section and the MBR membrane pool is 27h, the sludge return rate is 300%, the sludge discharge volume is 1%, and the sludge concentration is 10g / L;

[0064] Under these conditions, the MBR membrane flux is controlled at 12L / m 2 h; COD of MBR product water is about 200mg / L, ammonia nitrogen is about 28mg / L;

[0065] Step 2, the MBR product water enters ...

Embodiment 2

[0073] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7.5, total dissolved solids 16000mg / L, suspended solids 700mg / L, oil content 10mg / L, ammonia nitrogen 120mg / L, total hardness (CaCO 3 meter) 1200mg / L, total alkalinity (CaCO 3 Total) 500mg / L, Na + 7000mg / L, Cl - 9000mg / L, SO 4 2- 1100mg / L, COD 1300mg / L.

[0074] The processing steps are as follows:

[0075] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of anoxic section A is 5h, the total residence time of aerobic O section and MBR membrane pool is 30h, the sludge return rate is 350%, the sludge discharge volume is 1.5%, and the sludge concentration is 11g / L;

[0076] Under these conditions, the MBR membrane flux is controlled at 11L / m 2 h; COD of MBR product water is about 280mg / L, ammonia nitrogen is about 65mg / L;

[0077] Step 2: Before the MBR product water ent...

Embodiment 3

[0085] The main water quality characteristics of gas field produced water are: influent pH 8, total dissolved solids 22000mg / L, suspended solids 1500mg / L, oil content 20mg / L, ammonia nitrogen 250mg / L, total hardness (CaCO 3 meter) 1800mg / L, total alkalinity (CaCO 3 Total) 750mg / L, Na + 10000mg / L, Cl - 12000mg / L, SO 4 2- 1500mg / L, COD 1500mg / L.

[0086] The processing steps are as follows:

[0087] Step 1: The produced water from the gas field enters the A / O / MBR unit sequentially to form the MBR produced water. Among them, the residence time of the anoxic section A is 6h, the total residence time of the aerobic O section and the MBR membrane pool is 32h, the sludge return rate is 400%, the sludge discharge volume is 2%, and the sludge concentration is 12g / L;

[0088] Under these conditions, the MBR membrane flux is controlled at 12L / m 2 h; COD of MBR product water is about 360mg / L, ammonia nitrogen is about 110mg / L;

[0089] Step 2, before the MBR product water enters t...

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