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 catalytic ozonation-A / O / MBR-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 factory low-temperature waste heat is utilized to realize the injecting decreasing recycling of the water reproduced in the gas field; and the obtained 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 ozone catalytic oxidation-A / O / MBR-high-efficiency hard removal filtration-membrane distillation technology to treat gas field produced water by reducing injection and recycling. 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...

Examples

Embodiment 1

[0057] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7, total dissolved solids 23000mg / L, suspended solids 300mg / L, oil content 5mg / L, ammonia nitrogen 50mg / L, according to CaCO 3 The total hardness is 800mg / L, according to CaCO 3 Total alkalinity 250mg / L, Na + 4000mg / L, Cl - 5000mg / L, SO 4 2- 800mg / L, COD 1500mg / L.

[0058] The processing steps are as follows:

[0059] Step 1, the gas field produced water enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 7, the residence time is 1h, and the ozone concentration is 125mg / L;

[0060] Under these conditions, the dosage of ozone is 800mg / L; the COD in the ozone catalytic oxidation water is about 700mg / L, and the ammonia nitrogen is about 47mg / L;

[0061] Step 2: Ozone catalytic oxidation effluent enters the A / O / MBR unit to form MBR product water. Among them, the residence time of the anoxic section A is 4h, the tota...

Embodiment 2

[0069] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7.5, total dissolved solids 30000mg / L, suspended solids 700mg / L, oil content 10mg / L, ammonia nitrogen 120mg / L, according to CaCO 3 The total hardness is 1200mg / L, according to CaCO 3 Total alkalinity 500mg / L, Na + 7000mg / L, Cl - 9000mg / L, SO 4 2- 1100mg / L, COD 2200mg / L.

[0070] The processing steps are as follows:

[0071] Step 1. Before the produced water from the gas field enters the ozone catalytic oxidation unit, set up a pipeline dosing pump and add sodium hypochlorite to remove the remaining small amount of ammonia nitrogen in the wastewater. After dosing, the effluent enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 7.5, the residence time is 1.5h, and the ozone concentration is 130mg / L;

[0072] Under these conditions, the dosage of ozone is 1200mg / L; the COD in the ozone catalytic oxidation water is ...

Embodiment 3

[0081] The main water quality characteristics of gas field produced water are: influent pH 8, total dissolved solids 35000mg / L, suspended solids 1500mg / L, oil content 20mg / L, ammonia nitrogen 250mg / L, according to CaCO 3 The total hardness is 1800mg / L, according to CaCO 3 Total alkalinity 750mg / L, Na + 10000mg / L, Cl - 12000mg / L, SO 4 2- 1500mg / L, COD 3000mg / L.

[0082] The processing steps are as follows:

[0083] Step 1. Before the produced water from the gas field enters the ozone catalytic oxidation unit, set up a pipeline dosing pump and add sodium hypochlorite to remove the remaining small amount of ammonia nitrogen in the wastewater. After dosing, the effluent enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 8, the residence time is 2h, and the ozone concentration is 135mg / L;

[0084] Under these conditions, the dosage of ozone is 1500mg / L; the COD in the ozone catalytic oxidation water is about 1050mg / L, and ...

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 ozone catalytic oxidation-A / O / MBR-high-efficiency hard removal filtration-membrane distillation technology to treat gas field produced water by reducing injection and recycling. 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...

Examples

Embodiment 1

[0057] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7, total dissolved solids 23000mg / L, suspended solids 300mg / L, oil content 5mg / L, ammonia nitrogen 50mg / L, according to CaCO 3 The total hardness is 800mg / L, according to CaCO 3 Total alkalinity 250mg / L, Na + 4000mg / L, Cl - 5000mg / L, SO 4 2- 800mg / L, COD 1500mg / L.

[0058] The processing steps are as follows:

[0059] Step 1, the gas field produced water enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 7, the residence time is 1h, and the ozone concentration is 125mg / L;

[0060] Under these conditions, the dosage of ozone is 800mg / L; the COD in the ozone catalytic oxidation water is about 700mg / L, and the ammonia nitrogen is about 47mg / L;

[0061] Step 2: Ozone catalytic oxidation effluent enters the A / O / MBR unit to form MBR product water. Among them, the residence time of the anoxic section A is 4h, the tota...

Embodiment 2

[0069] The main water quality characteristics of the produced water of a certain gas field are: influent pH 7.5, total dissolved solids 30000mg / L, suspended solids 700mg / L, oil content 10mg / L, ammonia nitrogen 120mg / L, according to CaCO 3 The total hardness is 1200mg / L, according to CaCO 3 Total alkalinity 500mg / L, Na + 7000mg / L, Cl - 9000mg / L, SO 4 2- 1100mg / L, COD 2200mg / L.

[0070] The processing steps are as follows:

[0071] Step 1. Before the produced water from the gas field enters the ozone catalytic oxidation unit, set up a pipeline dosing pump and add sodium hypochlorite to remove the remaining small amount of ammonia nitrogen in the wastewater. After dosing, the effluent enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 7.5, the residence time is 1.5h, and the ozone concentration is 130mg / L;

[0072] Under these conditions, the dosage of ozone is 1200mg / L; the COD in the ozone catalytic oxidation water is ...

Embodiment 3

[0081] The main water quality characteristics of gas field produced water are: influent pH 8, total dissolved solids 35000mg / L, suspended solids 1500mg / L, oil content 20mg / L, ammonia nitrogen 250mg / L, according to CaCO 3 The total hardness is 1800mg / L, according to CaCO 3 Total alkalinity 750mg / L, Na + 10000mg / L, Cl - 12000mg / L, SO 4 2- 1500mg / L, COD 3000mg / L.

[0082] The processing steps are as follows:

[0083] Step 1. Before the produced water from the gas field enters the ozone catalytic oxidation unit, set up a pipeline dosing pump and add sodium hypochlorite to remove the remaining small amount of ammonia nitrogen in the wastewater. After dosing, the effluent enters the ozone catalytic oxidation unit to form ozone catalytic oxidation effluent; the influent pH is 8, the residence time is 2h, and the ozone concentration is 135mg / L;

[0084] Under these conditions, the dosage of ozone is 1500mg / L; the COD in the ozone catalytic oxidation water is about 1050mg / L, and ...

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