Shale gas development wastewater treatment system, exploration system and exploitation system

Abstract

The utility model relates to the technical field of water treatment, in particular to a shale gas development wastewater treatment system, an exploration system and an exploitation system. The shale gas development wastewater treatment system comprises a flocculation sedimentation tank, a high-pressure reverse osmosis device (high-pressure RO device) and a disc tube type reverse osmosis device (DTRO device) which are communicated in sequence. According to the utility model, the flocculation sedimentation tank, the high-pressure reverse osmosis device and the disc tube type reverse osmosis device which are communicated in sequence are arranged, so that the concentration multiple of wastewater can be improved through the combination of the high-pressure reverse osmosis device and the disc tube type reverse osmosis device, and chloride ions and soluble solids in the wastewater can be effectively removed; the content of chloride ions and soluble solids in purified water is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a shale gas development wastewater treatment system, exploration system and exploitation system. BACKGROUND

[0002] Shale gas refers to mature dark shale or high-carbon shale rich in organic matter, in which natural gas of commercial value of biological origin, pyrolysis origin and mixed origin is stored and preserved due to adsorption of organic matter or existence of cracks and matrix pores in the rock. Shale gas is continuously generated biogas, thermogenic gas or a mixture of the two, which exists in natural cracks and pores in a free state, on the surface of cheese root and clay particles in an adsorbed state, and in a small amount in cheese root and asphaltene in a dissolved state, and the proportion of free gas is generally 20%-85%. Shale gas is a clean, low-carbon and high-reserve natural gas energy, which has a broad application prospect.

[0003] In the related art, hydraulic fracturing technology is usually used for shale gas exploitation. Specifically, in the process of shale gas exploitation, the fracturing fluid is injected into the well by using the hydraulic fracturing technology, and the injected water in the formation will be returned and discharged at different stages of shale gas production, that is, fracturing return fluid and produced water, collectively referred to as produced water. The fracturing return fluid return stage has the characteristics of large water discharge, low salt content and large amount of suspended solids, but the continuous period is short. Then enter the produced water return stage, the water discharge gradually decreases, the salt content gradually increases, the content of divalent metal ions continuously increases, and the suspended solids greatly decrease. The water quality of produced water fluctuates greatly, because the fracturing fluid used in hydraulic fracturing operation contains a large amount of high molecular polymer, in addition to the components of the fracturing fluid, the produced water also contains pollutants such as silt, and the salinity mainly composed of sodium chloride gradually increases, and some areas of the formation may contain heavy metals and radioactive elements with the return of the produced water.

[0004] During the exploration and exploitation of shale gas, drilling wastewater, well washing wastewater, fracturing return water, and gas production water are produced, and the chlorine ion content in these waters is high. Conventional biochemical treatment processes cannot reduce the chlorine ion content to the qualified discharge standard (under direct discharge conditions, the chlorine ion content is less than or equal to 300 ppm, and the total dissolved solids TDS is less than or equal to 1000 ppm; under indirect discharge conditions, the chlorine ion content is less than or equal to 1000 ppm, and the total dissolved solids TDS is less than or equal to 2000 ppm). CONTENT OF THE UTILITY MODEL

[0005] In view of the above-mentioned shortcomings of the prior art, the shale gas development wastewater treatment system, exploration system and exploitation system are provided to reduce the chlorine ion and dissolved solids content in the shale gas development wastewater.

[0006] To achieve the above object, the scheme of the present application is as follows:

[0007] In a first aspect, the shale gas development wastewater treatment system comprises a flocculation sedimentation tank, a high-pressure reverse osmosis device (high-pressure RO device) and a disc tube reverse osmosis device (DTRO device) connected in sequence.

[0008] Specifically, the principle of the shale gas development wastewater treatment system is that the flocculation sedimentation tank, the high-pressure reverse osmosis device and the disc tube reverse osmosis device are connected in sequence, so that the concentration multiple of the wastewater is improved through the combination of the high-pressure reverse osmosis device and the disc tube reverse osmosis device, and the chlorine ions and the dissolved solids in the wastewater are effectively removed, thereby reducing the content of chlorine ions and dissolved solids in the purified water.

[0009] Optionally, the shale gas development wastewater treatment system further comprises an anoxic-aerobic tank (A / O tank) located on the connecting pipeline between the flocculation sedimentation tank and the high-pressure reverse osmosis device.

[0010] Specifically, by adding the anoxic-aerobic tank located on the connecting pipeline between the flocculation sedimentation tank and the high-pressure reverse osmosis device, the shale gas development wastewater treatment system can effectively treat the suspended pollutants and soluble organic matter in the wastewater through the anoxic-aerobic tank, thereby purifying the water quality.

[0011] Optionally, the shale gas development wastewater treatment system further comprises a flat sheet membrane bioreactor (MBR device) located on the connecting pipeline between the anoxic-aerobic tank and the high-pressure reverse osmosis device.

[0012] Specifically, by adding the flat sheet membrane bioreactor located on the connecting pipeline between the anoxic-aerobic tank and the high-pressure reverse osmosis device, the shale gas development wastewater treatment system can effectively treat the biological pollutants such as Escherichia coli in the wastewater through the flat sheet membrane bioreactor, thereby purifying the water quality.

[0013] Optionally, the shale gas development wastewater treatment system further comprises an ultrafiltration device (UF device) located on the connecting pipeline between the flat sheet membrane bioreactor and the high-pressure reverse osmosis device.

[0014] Specifically, by adding the ultrafiltration device located on the connecting pipeline between the flat sheet membrane bioreactor and the high-pressure reverse osmosis device, the shale gas development wastewater treatment system can effectively intercept macromolecular substances in the wastewater through the ultrafiltration device, thereby purifying the water quality.

[0015] Optionally, the disc tube reverse osmosis device is provided with a waste liquid outlet, and the shale gas development wastewater treatment system further comprises a multiple-effect evaporator and a purified water discharge pipeline, the purified water discharge pipeline is communicated with the waste liquid outlet, the multiple-effect evaporator is provided with a filtrate outlet and a concentrated liquid outlet, the multiple-effect evaporator is communicated with the waste liquid outlet, and the filtrate outlet is communicated with the purified water discharge pipeline.

[0016] Specifically, the shale gas development wastewater treatment system further comprises a multiple-effect evaporator and a purified water discharge pipeline, the purified water discharge pipeline is communicated with the waste liquid outlet, the multiple-effect evaporator is provided with a filtrate outlet and a concentrated liquid outlet, the multiple-effect evaporator is communicated with the waste liquid outlet, and the filtrate outlet is communicated with the purified water discharge pipeline, so that the concentrated liquid obtained after being treated by the disc tube reverse osmosis device can be secondarily treated by the multiple-effect evaporator, and then the coarse solid salt material in the concentrated liquid can be recovered, thereby improving resource utilization and increasing income.

[0017] Optionally, the shale gas development wastewater treatment system further comprises a crystallizer, and the crystallizer is communicated with the concentrated liquid outlet.

[0018] Specifically, the shale gas development wastewater treatment system further comprises a crystallizer, and the crystallizer is communicated with the concentrated liquid outlet.

[0019] Optionally, the crystallizer is provided with a solid salt outlet, and the shale gas development wastewater treatment system further comprises a solid salt storage container, the solid salt storage container is located below the crystallizer, and the solid salt storage container is communicated with the solid salt outlet.

[0020] Optionally, the multiple-effect evaporator is a three-effect multistage evaporator.

[0021] Specifically, the shale gas development wastewater treatment system further comprises a multiple-effect evaporator, and the multiple-effect evaporator is a three-effect multistage evaporator, so that the heating time of the material can be shortened, the energy consumption can be reduced, and then the income can be increased.

[0022] In a second aspect, the utility model also provides a shale gas exploration system, the shale gas exploration system includes the shale gas development wastewater treatment system of above.

[0023] In a third aspect, the utility model also provides a shale gas exploitation system, the shale gas exploitation system includes the shale gas development wastewater treatment system. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is the structural schematic view of shale gas development wastewater treatment system of example 1;

[0025] Figure 2A structural schematic diagram of a shale gas development wastewater treatment system of Example 1;

[0026] Figure 3 A structural schematic diagram of a shale gas development wastewater treatment system of Example 3;

[0027] Figure 4 A structural schematic diagram of a shale gas development wastewater treatment system of Example 4.

[0028] Reference numerals

[0029] 1-flocculation sedimentation tank;

[0030] 2-anoxic-oxygen tank;

[0031] 3-flat plate membrane bioreactor;

[0032] 4-ultrafiltration device;

[0033] 5-high pressure reverse osmosis device;

[0034] 6-disk tube reverse osmosis device;

[0035] 7-multiple-effect evaporator;

[0036] 8-purified water discharge pipeline;

[0037] 9-crystallizer;

[0038] 10-solid salt storage container. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] It should be noted that all directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications will also change accordingly.

[0041] In the utility model, unless another definite provision and limitation, the terms "connect", "fix" and the like should be understood broadly, for example, "fix" can be fixed connection, also can be detachable connection, or be integrated, can be mechanical connection, also can be electrical connection, can be directly connected, also can be indirectly connected through intermediate medium, can be the communication or the interaction of two elements, unless another definite limitation, for ordinary skilled person in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0042] In addition, the meaning of "and / or" appearing throughout the text is that it includes three parallel solutions, for example, "A and / or B", including A solution, or B solution, or A and B solution. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled person in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the utility model.

[0043] In the related art, shale gas exploration and exploitation can produce drilling wastewater, well washing wastewater, fracturing backflow water, gas production water and the like, the chloride ion content in these waters is high, and the conventional biochemical treatment process cannot reduce the chloride ion content to the qualified discharge standard (under direct discharge conditions, the chloride ion is less than or equal to 300 ppm, and the dissolved solids TDS is less than or equal to 1000 ppm; under indirect discharge conditions, the chloride ion is less than or equal to 1000 ppm, and the dissolved solids TDS is less than or equal to 2000 ppm).

[0044] Based on the above technical problem, one embodiment of the utility model provides a kind of shale gas development wastewater treatment system, which includes flocculation sedimentation tank 1, anoxic-aerobic tank (A / O tank) 2, flat sheet membrane bioreactor (MBR device) 3, ultrafiltration device (UF device) 4, high pressure reverse osmosis device (high pressure RO device) 5 and disc tube reverse osmosis device (DTRO device) 6 in sequence.

[0045] In another embodiment of the utility model, disc tube reverse osmosis device 6 is provided with waste liquid outlet, and the shale gas development wastewater treatment system further includes multi-effect evaporator 7 and purified water discharge pipeline 8, purified water discharge pipeline 8 is communicated with the waste liquid outlet of disc tube reverse osmosis device 6, the multi-effect evaporator is provided with filtrate outlet and concentrated liquid outlet, the multi-effect evaporator is communicated with the waste liquid outlet, the filtrate outlet is communicated with the purified water discharge pipeline, and multi-effect evaporator 7 adopts three-effect multi-stage evaporator.

[0046] In another embodiment of the utility model, the shale gas development wastewater treatment system further includes crystallizer 9, and crystallizer 9 is communicated with concentrated liquid outlet.

[0047] In another embodiment of the present application, the crystallizer 9 is provided with a solid salt outlet, and the shale gas development wastewater treatment system further comprises a solid salt storage container 10, which is located below the crystallizer 9 and is connected to the solid salt outlet.

[0048] The shale gas exploration system comprises the shale gas development wastewater treatment system as described above.

[0049] The shale gas exploration system comprises the shale gas development wastewater treatment system as described above.

[0050] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present application, however, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details.

[0051] Embodiment 1

[0052] Please refer to Figure 1 , Figure 1 The shale gas development wastewater treatment system is used for treating wastewater generated in the process of shale gas development (such as exploration and exploitation), and comprises a flocculation sedimentation tank 1, an anoxic-oxic tank (A / O tank) 2, a flat sheet membrane bioreactor (MBR device) 3, an ultrafiltration device (UF device) 4, a high-pressure reverse osmosis device (high-pressure RO device) 5 and a disc tube reverse osmosis device (DTRO device) 6 which are sequentially connected.

[0053] Please continue to refer to Figure 1 , the flocculation sedimentation tank 1 is used for removing impurities such as suspended solids, silt, organic matter and heavy metals in wastewater. The flocculation sedimentation tank is provided with a feeding port (not shown), a liquid inlet and a liquid outlet. The flocculation agent can be fed into the flocculation sedimentation tank 1 through the feeding port, and the flocculation agent can make the impurities such as suspended solids, silt, organic matter and heavy metals in the wastewater gather in mutual contact to form larger flocculation bodies. The formed flocculation bodies can be precipitated to the bottom of the flocculation sedimentation tank 1 under the action of gravity, and then the wastewater is preliminarily treated.

[0054] Please continue to refer to Figure 1 , the anoxic-oxic tank (A / O tank) 2 is used for removing organic matter, nitrogen elements and phosphorus elements in wastewater by denitrification, nitrification and phosphorus uptake under aerobic conditions, and further treating the wastewater after preliminary treatment. The first end of the anoxic-oxic tank (A / O tank) 2 is connected to the liquid outlet of the flocculation sedimentation tank 1.

[0055] Specifically, the present embodiment is capable of effectively treating the suspended pollutants and soluble organic matters in the wastewater through the anoxic-oxic tank 2, and further purifying the water quality by additionally disposing the anoxic-oxic tank 2 on the communication pipeline between the flocculation sedimentation tank 1 and the high-pressure reverse osmosis device 5.

[0056] Please continue to refer to Figure 1 The flat sheet membrane bioreactor (MBR device) 3 is used to remove the microorganisms, activated sludge, macromolecular organic matters and other impurities in the wastewater through the membrane separation technology and biological treatment technology, and further purify the water quality. The first end of the flat sheet membrane bioreactor (MBR device) 3 is communicated with the second end of the anoxic-oxic tank (A / O tank) 2.

[0057] Specifically, the present embodiment is capable of effectively treating the biological pollutants such as coliform bacteria in the wastewater through the flat sheet membrane bioreactor 3, and further purifying the water quality by additionally disposing the flat sheet membrane bioreactor 3 on the communication pipeline between the anoxic-oxic tank 2 and the high-pressure reverse osmosis device 5.

[0058] Please continue to refer to Figure 1 The ultrafiltration device (UF device) 4 is used to remove the macromolecular solvents and other impurities through the asymmetric microporous structure and semi-permeable membrane medium, and further purify the water quality. The first end of the ultrafiltration device (UF device) 4 is communicated with the second end of the flat sheet membrane bioreactor (MBR device) 3.

[0059] Specifically, the present embodiment is capable of effectively removing the macromolecular solvents and other impurities in the wastewater through the ultrafiltration device 4, and further purifying the water quality by additionally disposing the ultrafiltration device on the communication pipeline between the flat sheet membrane bioreactor 3 and the high-pressure reverse osmosis device 5.

[0060] Please continue to refer to Figure 1 The high-pressure reverse osmosis device (high-pressure RO device) 5 is used to remove the chloride ions, bacteria, viruses, organic matters, colloids and other impurities in the wastewater through the selective permeability of the semi-permeable membrane, and further purify the water quality. The first end of the high-pressure reverse osmosis device (high-pressure RO device) 5 is communicated with the second end of the ultrafiltration device (UF device) 4.

[0061] Please continue to refer to Figure 1 The disc tube reverse osmosis device (DTRO device) 6 is used to remove the dissolved solids and other impurities in the wastewater through the reverse osmosis technology, and further purify the water quality. The first end of the disc tube reverse osmosis device (DTRO device) 6 is communicated with the second end of the high-pressure reverse osmosis device (high-pressure RO device) 5, and the disc tube reverse osmosis device 6 is provided with a waste liquid outlet.

[0062] The principle of the embodiment is that: by setting the communicating high-pressure reverse osmosis device 5 and the spiral-wound reverse osmosis device 6, the combination of the high-pressure reverse osmosis device 5 and the spiral-wound reverse osmosis device 6 can improve the concentration multiple of the wastewater, and further effectively remove the chloride ions and the dissolved solids in the wastewater, and reduce the chloride ion and the dissolved solids content in the purified water.

[0063] Embodiment 2

[0064] Please refer to Figure 2 , Figure 2 The structure diagram of the shale gas development wastewater treatment system shown in the embodiment is shown.

[0065] Please continue to refer to Figure 2 , the difference between the embodiment and the embodiment 1 is that the shale gas development wastewater treatment system further comprises a multiple-effect evaporator 7 and a purified water discharge pipeline 8.

[0066] Please continue to refer to Figure 2 , the purified water discharge pipeline 8 is communicated with the waste liquid outlet of the spiral-wound reverse osmosis device 6, the multiple-effect evaporator 7 is provided with a filtrate outlet and a concentrated liquid outlet, the multiple-effect evaporator 7 is communicated with the waste liquid outlet of the spiral-wound reverse osmosis device 6, the filtrate outlet of the multiple-effect evaporator 7 is communicated with the purified water discharge pipeline 8, and the multiple-effect evaporator 7 adopts a three-effect multi-stage evaporator.

[0067] Specifically, by additionally arranging the multiple-effect evaporator 7 and the purified water discharge pipeline 8, the purified water discharge pipeline 8 is communicated with the spiral-wound reverse osmosis device 6, the multiple-effect evaporator 7 is provided with a filtrate outlet and a concentrated liquid outlet, the multiple-effect evaporator 7 is communicated with the waste liquid outlet of the spiral-wound reverse osmosis device 6, and the filtrate outlet of the multiple-effect evaporator 7 is communicated with the purified water discharge pipeline 8, the concentrated liquid obtained after the spiral-wound reverse osmosis device 6 is treated can be secondarily treated by the multiple-effect evaporator 7, and then the coarse solid salt material in the concentrated liquid is recovered, so that the resource utilization rate is improved and the income is increased. By arranging the multiple-effect evaporator 7 to adopt a three-effect multi-stage evaporator, the material heating time can be shortened, the energy consumption can be reduced, and the income can be further improved.

[0068] Embodiment 3

[0069] Please refer to Figure 3 , Figure 2 The structure diagram of the shale gas development wastewater treatment system shown in the embodiment is shown.

[0070] Please continue to refer to Figure 3 , the difference between the embodiment and the embodiment 2 is that the shale gas development wastewater treatment system further comprises a crystallizer 9, the crystallizer 9 is used for crystallizing the concentrated liquid obtained after the multiple-effect evaporator 7 is treated, the crystallizer 9 is communicated with the concentrated liquid outlet of the multiple-effect evaporator 7, and the crystallizer 9 is provided with a solid salt outlet.

[0071] Specifically, the embodiment adds the crystallizer 9, and the crystallizer 9 is communicated with the concentrated liquid outlet of the multi-effect evaporator 7, so that the solid salt can be separated from the concentrated liquid by the crystallizer 9, the solid salt byproduct is obtained, and the resource utilization rate and the income are improved.

[0072] Embodiment 4

[0073] Please refer to Figure 4 , Figure 4 The structure diagram of the shale gas development wastewater treatment system shown in the embodiment is shown.

[0074] Please continue to refer to Figure 4 The difference between the embodiment and the embodiment 3 is that the shale gas development wastewater treatment system further comprises a solid salt storage container 10, the solid salt storage container 10 is located below the crystallizer 9, and the solid salt storage container 10 is communicated with the solid salt outlet of the crystallizer 9.

[0075] Not limited to this, the embodiment of the utility model further provides a shale gas exploration system, the shale gas exploration system includes the shale gas development wastewater treatment system as described above.

[0076] Not limited to this, the embodiment of the utility model further provides a shale gas exploitation system, the shale gas exploitation system includes the shale gas development wastewater treatment system as described above.

[0077] The above embodiment only exemplarily illustrates the principle and effect of the utility model, and is not used to limit the utility model. Any person skilled in the art can modify or change the above embodiment without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the utility model should be covered by the claims of the utility model.

Claims

1. A system for treating wastewater from shale gas development, the system comprising: The shale gas development wastewater treatment system comprises a flocculation sedimentation tank, a high-pressure reverse osmosis device and a disc tube reverse osmosis device connected in sequence. The shale gas development wastewater treatment system further comprises an anoxic-oxygen tank, which is located on the connecting pipeline between the flocculation sedimentation tank and the high-pressure reverse osmosis device. The shale gas development wastewater treatment system further comprises a flat-plate membrane bioreactor, which is located on the connecting pipeline between the anoxic-oxygen tank and the high-pressure reverse osmosis device. The shale gas development wastewater treatment system further comprises an ultrafiltration device, which is located on the connecting pipeline between the flat-plate membrane bioreactor and the high-pressure reverse osmosis device.

2. The shale gas development wastewater treatment system of claim 1, wherein, The disc tube reverse osmosis device is provided with a waste liquid outlet, and the shale gas development wastewater treatment system further comprises a multi-effect evaporator and a purified water discharge pipeline, wherein the purified water discharge pipeline is connected to the waste liquid outlet, the multi-effect evaporator is provided with a filtrate outlet and a concentrated liquid outlet, the multi-effect evaporator is connected to the waste liquid outlet, and the filtrate outlet is connected to the purified water discharge pipeline.

3. The shale gas development wastewater treatment system of claim 2, wherein, The shale gas development wastewater treatment system further comprises a crystallizer, which is connected to the concentrated liquid outlet.

4. The shale gas development wastewater treatment system of claim 3, wherein, The crystallizer is provided with a solid salt outlet, and the shale gas development wastewater treatment system further comprises a solid salt storage container, which is located below the crystallizer and is connected to the solid salt outlet.

5. The shale gas development wastewater treatment system of claim 2, wherein, The multi-effect evaporator is a three-effect multi-stage evaporator.

6. A shale gas exploration system characterized by, The shale gas exploration system comprises the shale gas development wastewater treatment system according to any one of claims 1-5.

7. A shale gas extraction system characterized by, The shale gas exploitation system comprises the shale gas development wastewater treatment system according to any one of claims 1-5.

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