Process for producing hydrogen from oil and gas field produced water

Abstract

The invention discloses an oil-gas field produced water hydrogen production process. Clear water obtained after the produced water is subjected to physical oil removal and multi-layer filtration treatment of the water treatment module enters the steam supply module; clear water sequentially passes through a low-temperature evaporation device, a steam supply device and a low-temperature evaporation device of the steam supply module, steam generated after the clear water passes through the low-temperature evaporation device generates condensate water at an outlet under normal pressure, and the condensate water enters the metal cracking steam hydrogen production module through dry saturated steam generated by the steam supply device; concentrated liquid at the bottoms of the low-temperature evaporation device and the steam supply device enters the multi-effect crystallization module; the dry saturated steam enters the metal cracking water vapor hydrogen production module, the steam is distributed to a plurality of cracking reaction devices of the hydrogen production reaction system through a steam distribution cylinder to obtain hydrogen with high purity, and the hydrogen is output through a conveying system. The device has the beneficial effects that the design is reasonable, environmental pollution is avoided, and the requirements of safe and environment-friendly exploration and development are met.

Description

TECHNICAL FIELD

[0001] The present application relates to an oil and gas field produced water treatment process, in particular to an oil and gas field produced water hydrogen production process, and belongs to the technical field of oil and gas exploration and development. BACKGROUND

[0002] A large amount of produced water is generated in the process of oil field development, and most of the produced water is treated and then used for balancing formation pressure and water injection for oil displacement by means of reinjection; however, in some blocks, the produced water cannot be reinjected due to the lack of effective oil and water treatment capacity; in particular, the associated water produced in the exploitation of coalbed methane and natural gas has a relatively small water production, and the well site is not complete, and the investment in the construction of a treatment station is not suitable.

[0003] For these wastewaters, the oil and gas field usually adopts the following three ways:

[0004] First, a water treatment station is constructed by adopting the processes of adding chemicals, multi-stage sedimentation, oil removal, and multi-stage filtration, so that the produced water meets the requirements for formation reinjection, and is reinjected into the same layer or invalidly reinjected; this water treatment process is complex, has many types of equipment, occupies a large area, has a large amount of chemical agent, has a high comprehensive treatment cost, and has a large investment in the treatment station;

[0005] Second, the produced water is transported to other treatment stations or local water treatment plants for treatment in the case of no station construction conditions; this way increases the transportation cost and the cost of entrusting water treatment;

[0006] Third, in the case of not meeting the above conditions, only the way of natural evaporation or the way of invalid reinjection without treatment can be selected for individual blocks, which seriously affects the natural ecology and destroys the formation, and pollutes the environment. SUMMARY

[0007] In order to overcome the above-mentioned deficiencies of the existing produced water treatment technology of oil and gas development, the present application provides an oil and gas field produced water hydrogen production process.

[0008] The technical scheme adopted by the present application to solve its technical problems is: an oil and gas field produced water hydrogen production process, comprising a water treatment module, a steam supply module, a metal cracking water steam hydrogen production module, and an auxiliary module; the clear water obtained after the physical oil removal and multi-layer filtration treatment of the produced water by the water treatment module enters the steam supply module.

[0009] The clear water successively passes through a low-temperature evaporation device and a steam supply device of the steam supply module; the working pressure of the low-temperature evaporation device is -0.08 to -0.15 MPa, and the temperature is 30 to 40 DEG C; the steam after the clear water passes through the low-temperature evaporation device generates condensate water at the outlet under normal pressure; the condensate water generates 160 DEG C dry saturated steam through the steam supply device, and enters the metal cracking water steam hydrogen production module; the concentrated liquid at the bottom of the low-temperature evaporation device and the steam supply device enters a multi-effect crystallization module.

[0010] The dry saturated steam enters the metal cracking steam hydrogen production module, and the dry saturated steam enters the steam distribution cylinder with a pressure of 0.62-0.75 MPa, and the steam distribution cylinder distributes the steam to a plurality of cracking reaction devices of the hydrogen production reaction system; the steam reacts with the metal cracking agent in the cracking reaction device with a working temperature of 158-166 DEG C and a working pressure of 0.6-0.7 MPa to produce hydrogen gas containing a small amount of steam and condensed water, the hydrogen gas enters the condensation heat exchange device to increase the purity of the hydrogen gas, and the hydrogen gas enters the transfer tank and the purification device in sequence to obtain high-purity hydrogen gas.

[0011] The water treatment module adopts electromagnetic pulse sewage oil removal + filter device, or electromagnetic pulse sewage oil removal device + graphene efficient oil-water treatment device, or graphene oil-water treatment device to treat the produced water, and the obtained clean water has an oil content of ≤3 mg / l and a suspended substance content of ≤15 mg / l.

[0012] The condensate water at the outlet of the low-temperature evaporation device in the steam supply module has a turbidity of ≤5.0 FTU, a hardness of ≤0.03 mmol / L or a calcium carbonate content of ≤3 mg / L, a PH of 7.0-10.5 at 25 DEG C, a dissolved oxygen content of ≤0.1 mg / L, an oil content of ≤2 mg / L, and an iron content of ≤0.3 mg / L.

[0013] The pressure of the 160 DEG C dry saturated steam generated after the condensate water enters the steam supply device is 0.65 MPa.

[0014] In the metal cracking steam hydrogen production module, the dry saturated steam sequentially passes through the steam distribution cylinder, the cracking reaction device, the condensation heat exchange device, the pressure stabilizing and flow stabilizing system, and the purification device.

[0015] The saturated steam entering the steam distribution cylinder has a temperature of 164-170 DEG C and a pressure of about 0.62-0.75 MPa, and the steam distribution cylinder distributes the saturated steam to a plurality of cracking reaction devices of the hydrogen production reaction system.

[0016] The cracking reaction device has a working temperature of 158-166 DEG C and a working pressure of 0.6-0.7 MPa, and the saturated steam reacts with the metal cracking agent in the cracking reaction device to produce hydrogen gas, wherein the metal cracking agent comprises aluminum, iron, manganese, carbon, NaCl, and NaHSO4; at the same time, a series of displacement reactions, electrochemical reactions, and oxidation-reduction reactions of other metals, metal compounds, and water under additional reaction conditions assist to produce hydrogen gas containing a small amount of steam.

[0017] The hydrogen gas containing a small amount of water vapor is subjected to air cooling + water cooling heat exchange + gas-liquid separation or water cooling heat exchange + gas-liquid separation of the condensation heat exchange system, so that hydrogen gas with a temperature of 30-55 DEG C and a pressure of 0.2-0.45 MPa is obtained.

[0018] The hydrogen gas produced by the condensation heat exchange system enters a transfer tank for pressure and flow stabilization, so that hydrogen gas with a temperature of 30-50 DEG C and a pressure of 0.18-0.40 MPa is obtained, and the purity of the hydrogen gas is greater than or equal to 94%.

[0019] The present application has the advantages of reasonable design, realization of on-site treatment and recycling of produced water without construction of a produced water treatment station, reduction of transportation and outsourcing treatment costs, less use of chemical agents, effective reduction of comprehensive treatment cost, no damage to stratum and natural ecology, no pollution to the environment, and compliance with the requirements of safe and environmentally-friendly exploration and development. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of the hydrogen production system of the oil and gas field produced water according to the present application.

[0021] Figure 2 is a schematic diagram of the structure of the hydrogen production system of the oil and gas field produced water according to the present application.

[0022] In the figure: 1. water treatment module, 2. steam supply module, 3. multi-effect crystallization module, 4. metal cracking water vapor hydrogen production module, 5. auxiliary module, 11. water treatment device, 12. buffer water tank, 13. fine filtration device, 14. clean water tank, 21. steam supply device, 22. bottom concentrated liquid pipeline, 23. heat exchanger, 24. low-temperature evaporation device, 31. multi-effect evaporation crystallization device, 32. steam separation cylinder I, 33. condensation device, 41. steam separation cylinder II, 42. cracking reaction device, 43. transfer tank, 44. purification device, 45. condensation heat exchange device, 51. nitrogen replacement device, 52. electric control device, 311. evaporator, 312. crystallization tank. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings and examples. However, those skilled in the art should know that the present application is not limited to the specific embodiments listed, and as long as it conforms to the spirit of the present application, it should be included in the protection scope of the present application.

[0024] In the description of the present application, it should be noted that the terms "vertical", "upper", "lower", "left", "right", "horizontal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description or simplification of the description of the present application, and therefore cannot be understood as limiting the devices or elements referred to in a particular orientation, constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0025] In the description of the present application, it is also necessary to explain that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, the connection can be fixed connection, or detachable connection, can be direct connection, or indirect connection, or integrally connected, can be mechanical connection, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] Referring to the accompanying drawings Figure 1 The present application is a kind of oil and gas field produced water hydrogen process, including water treatment module 1, steam supply module 2, metal cracking steam hydrogen module 4, auxiliary module 5;The clean water obtained after the produced water is treated by physical oil removal and multi-layer filtration of water treatment module 1 enters steam supply module 2.

[0027] The clean water successively passes through low-temperature evaporation device 24 and steam supply device 21 of steam supply module 2, the working pressure of low-temperature evaporation device 24 is-0.08~ -0.15MPa, and the temperature is 30~40℃, the steam after the clean water passes through low-temperature evaporation device 24 generates condensate water at the outlet under normal pressure, and the condensate water enters metal cracking steam hydrogen module 4 by 160℃ dry saturated steam generated by steam supply device 21;The concentrated liquid at the bottom of low-temperature evaporation device 24 and steam supply device 21 enters multi-effect crystallization module 3.

[0028] The dry saturated steam enters the metal cracking steam hydrogen module (4), and the dry saturated steam enters the steam cylinder with a pressure of 0.62~0.75MPa, and the steam is distributed to several cracking reaction devices of the hydrogen production reaction system by the steam cylinder;The steam reacts with the metal cracking agent in the cracking reaction device at a working temperature of 158~166℃ and a working pressure of 0.6~0.7MPa, to produce hydrogen containing a small amount of water vapor and condensate water, the hydrogen enters the condensation heat exchange device to improve the purity of the hydrogen, and the hydrogen successively enters the transfer tank and the purification device to obtain high-purity hydrogen, which is output through the conveying system.

[0029] According to different working conditions, the hydrogen can be further purified by the purification device 44 to meet the user's requirements.

[0030] Further, the water treatment module 1 adopts electromagnetic pulse sewage oil removal + filter device, or electromagnetic pulse sewage oil removal device + graphene high-efficiency oil-water treatment device, or graphene oil-water treatment device to treat the produced water, and the obtained clean water has an oil content of ≤3mg / l and a suspended solid content of ≤15mg / l.

[0031] The condensate water quality at the outlet of the low-temperature evaporation device 24 in the steam supply module 2 is: turbidity ≤ 5.0 FTU; hardness ≤ 0.03 mmol / L, or ≤ 3 mg / L in terms of calcium carbonate content; PH at 25℃ is 7.0-10.5; dissolved oxygen ≤ 0.1 mg / L; oil ≤ 2 mg / L; iron content ≤ 0.3 mg / L.

[0032] The pressure of the 160℃ dry saturated steam generated after the condensate water enters the steam supply device 21 is 0.65 MPa.

[0033] In the metal cracking water steam hydrogen production module 4, the dry saturated steam passes through the gas distribution cylinder II 41, the cracking reaction device 42, the condensation heat exchange device 45, the pressure-stabilizing and flow-stabilizing transfer tank 43, and the purification device 44 in sequence.

[0034] The saturated water vapor entering the gas distribution cylinder II 41 has a temperature of 164-170℃ and a pressure of 0.62-0.75 MPa, and the gas distribution cylinder II 41 distributes the saturated water vapor to the cracking reaction devices 42 of the hydrogen production reaction system.

[0035] The working temperature of the cracking reaction device 42 is 158-166℃, and the working pressure is 0.6-0.7 MPa. The saturated water vapor reacts with the metal cracking agent in the cracking reaction device 42 to produce hydrogen gas, and the composition of the metal cracking agent includes aluminum, iron, manganese, carbon, NaCl, and NaHSO4. At the same time, a series of displacement reactions, electrochemical reactions, and oxidation-reduction reactions of other metals, metal compounds, and water under external reaction conditions assist in ensuring the continuous and stable reaction of aluminum and water, thereby producing hydrogen gas containing a small amount of water vapor.

[0036] The hydrogen gas containing a small amount of water vapor passes through the air cooling + water cooling heat exchange + gas-liquid separation or water cooling heat exchange + gas-liquid separation of the condensation heat exchange system to obtain hydrogen gas with a temperature of 30-55℃ and a pressure of 0.2-0.45 MPa.

[0037] The hydrogen gas produced by the condensation heat exchange system enters the transfer tank for pressure stabilization and flow stabilization to obtain hydrogen gas with a working temperature of 30-50℃ and a pressure of 0.18-0.4 MPa, and the purity of the hydrogen gas is ≥ 94%. The hydrogen gas is output through the delivery system.

[0038] The hydrogen production system matched with the oil and gas field produced water hydrogen production process will be further described below in combination with the accompanying drawings.

[0039] Referring to the accompanying drawings, Figure 1 An oil and gas field produced water hydrogen production system includes a water treatment module 1, a steam supply module 2, a multi-effect crystallization module 3, a metal cracking water steam hydrogen production module 4, and an auxiliary module 5.

[0040] The clean water obtained after the produced water is treated by the water treatment module 1 enters the steam supply module 2; the dry saturated steam produced after the clean water passes through the steam supply module 2 enters the metal cracking water vapor hydrogen production module 4; the hydrogen gas obtained by the cracking reaction, condensation heat exchange and purification of the dry saturated steam in the metal cracking water vapor hydrogen production module 4 is output through a conveying system.

[0041] Referring to the accompanying drawings Figure 2 The water treatment module 1 comprises a water treatment device 11, a fine filtration device 13 and a clean water tank 14 connected in sequence.

[0042] The product after the produced water is treated by the water treatment device 11 comprises oil, dirt and clean water, wherein the oil is conveyed to an oil tank through an oil pipeline, the dirt is discharged into a sewage pool through a dirt discharge pipe at the bottom of the water treatment device 11, and the clean water enters the steam supply module 2.

[0043] Preferably, the water treatment device 11 adopts a graphene treatment device or a high-frequency / electromagnetic pulse treatment device. The fine filtration device 13 adopts a filter material filter or a membrane filter, such as sand filter, walnut shell, anthracite, etc., and can also adopt a membrane filter, etc., to further filter the water treated by the water treatment device 11, so as to obtain clean water with higher water quality.

[0044] Preferably, a buffer water tank 12 with voltage stabilizing and current stabilizing functions is installed in series between the water treatment device 11 and the fine filtration device 13. After the water treated by the water treatment device 11 is stabilized in voltage and current by the buffer water tank 12, the liquid flow is more stable.

[0045] When the produced water is high in mineralization degree, the hydrogen production system is provided with a multi-effect crystallization module 3 to treat the bottom concentrated liquid discharged from the steam supply module 2. The steam supply module 2 is connected to the multi-effect crystallization module 3 to provide the required steam to the multi-effect crystallization module 3. When the produced water is low in mineralization degree, the multi-effect crystallization module 3 is not required.

[0046] The low-temperature evaporation device 24 and the steam supply device 21 of the steam supply module 2 are connected in sequence, and the product after the clean water passes through the low-temperature evaporation device 24 and the steam supply device 21 in sequence is dry saturated steam or comprises dry saturated steam and bottom concentrated liquid. The dry saturated steam enters the metal cracking water vapor hydrogen production module 4, and the bottom concentrated liquid enters the multi-effect crystallization module 3. Preferably, the steam supply device 21 is a steam boiler or a steam generator.

[0047] The metal cracking water vapor hydrogen production module 4 comprises a cracking reaction device 42 and a condensation heat exchange device 45 connected in sequence.

[0048] The dry saturated steam generated by the steam supply module 2 enters the cracking reaction device 42, and after the dry saturated steam is treated by the cracking reaction device 42, hydrogen gas containing a small amount of water vapor and condensed water are generated, wherein the hydrogen gas containing a small amount of water vapor enters the condensing heat exchange device 45, and the condensed water is returned to the clean water tank 14 of the water treatment module 1 through a water pipeline.

[0049] The water vapor hydrogen production module 4 further comprises a transfer tank 43 and a purification device 44, and the cracking reaction device 42, the condensing heat exchange device 45, the transfer tank 43 and the purification device 44 are connected in sequence. The water-containing hydrogen gas passes through the condensing heat exchange device 45 to cool and separate the water vapor in the hydrogen gas, the hydrogen gas enters the transfer tank 43 to stabilize the pressure and flow, and then passes through the purification device 44 to obtain hydrogen gas with high purity, and the hydrogen gas is output through a delivery system.

[0050] The steam supply device 21 and the cracking reaction device 42 are connected in series and have a steam cylinder II 41 with pressure stabilization and flow stabilization.

[0051] Specifically, the cracking agent is arranged in the reaction tank of the cracking reaction device 42, the dry saturated steam is cracked to generate hydrogen gas therein, the water vapor in the hydrogen gas is preliminarily cooled and separated out through the condensing heat exchange device II 45, the hydrogen gas enters the transfer tank 43 through a pipeline, the hydrogen gas enters the purification device II 44 after being stabilized in pressure and flow by the transfer tank 43, the hydrogen gas is further purified to reduce the water vapor content in the hydrogen gas, and finally hydrogen gas with high purity is obtained, and the hydrogen gas is output through a delivery system.

[0052] The multi-effect crystallization module 3 comprises a multi-effect evaporation crystallization device 31 and a condensing device 33.

[0053] According to the needs of the site, part of the gas produced by the steam supply device 21 of the steam supply module 2 enters the evaporator 311.

[0054] The bottom concentrated liquid produced by the low-temperature evaporation device 24 and the steam supply device 21 is generated as gas and concentrated liquid after passing through the evaporator 311 of the multi-effect evaporation crystallization device 31, the gas is discharged after being condensed in the condensing device 33; the concentrated liquid is discharged from the lower end of the evaporator 311 into the crystallization tank 312 and is discharged after crystallization. Preferably, after the crystalline salt is preliminarily crystallized and separated, it is sent to a related processing plant for fine screening.

[0055] The steam supply device 21 and the multi-effect evaporation crystallization device 31 are connected in series and have a steam cylinder I 32 with pressure stabilization and flow stabilization. Preferably, one end of the steam cylinder I 32 is in communication with the steam output pipeline of the steam boiler or the steam generator 21, and the other end is in communication with the inlet of the evaporator 311.

[0056] The auxiliary module 5 comprises an electric control device 52 for controlling the hydrogen production system and a nitrogen replacement device 51 for ensuring the safe operation of the hydrogen production system.

[0057] The nitrogen replacement device 51 is used for replacing oxygen in the steam supply module 2, the multi-effect crystallization module 3, the metal cracking water steam hydrogen production module 4 and the hydrogen production system pipeline with nitrogen. Generally, the nitrogen replacement device 51 replaces the steam supply module 2, the multi-effect crystallization module 3, the metal cracking water steam hydrogen production module 4 and the system pipeline with nitrogen before the hydrogen production system is operated, so as to ensure safe operation.

[0058] The hydrogen production system adopts a modular skid structure which is convenient for transportation and rapid disassembly and installation. Preferably, the hydrogen production system is divided into modules according to functions, that is, the water treatment module 1, the steam supply module 2, the multi-effect crystallization module 3, the metal cracking water steam hydrogen production module 4 and the auxiliary module 5 are respectively installed on one or more skid seats, so as to facilitate transportation and rapid disassembly and installation.

[0059] The hydrogen production system can set the number of various devices in each module according to the produced water amount and hydrogen production demand of the production site, and install the same type of devices in the module in series or parallel according to process needs, so as to effectively utilize resources for hydrogen production.

[0060] Embodiment:

[0061] The oil and gas field produced water hydrogen production process is applied to the XX condensate gas field of the XX oil field. The produced water in this block has a salinity of 40181 mg / L, which is high salinity produced water.

[0062] An oil and gas field produced water hydrogen production system includes a water treatment module 1, a steam supply module 2, a metal cracking water steam hydrogen production module 4 and an auxiliary module 5.

[0063] The oil and gas field produced water hydrogen production process is as follows:

[0064] First, the clean water obtained after the produced water is treated by the physical oil removal and multi-layer filtration of the water treatment module 1 enters the steam supply module 2.

[0065] The water treatment module 1 uses an electromagnetic pulse sewage oil removal + filtration device, or an electromagnetic pulse sewage oil removal device + graphene efficient oil-water treatment device, or a graphene oil-water treatment device to treat the produced water, and the obtained clean water has an oil content of 2.5 mg / l and a suspended solid content of 13 mg / l.

[0066] Then, the clean water generates dry saturated steam through the steam supply module 2

[0067] The clear water is sequentially passed through the low-temperature evaporation device 24 of the steam supply module 2 and the steam supply device 21, the working pressure of the low-temperature evaporation device 24 is -0.10 to -0.13 MPa, and the temperature is 34-36 ℃, the steam after the clear water passing through the low-temperature evaporation device 21 generates condensate water at the outlet under normal pressure, the condensate water enters the metal cracking water vapor hydrogen production module 4 through the 160 ℃ dry saturated steam generated by the steam supply device, and the concentrated liquid at the bottom of the low-temperature evaporation device 24 and the steam supply device 21 enters the multi-effect crystallization module 3.

[0068] The condensate water at the outlet of the low-temperature evaporation device in the steam supply module 2 has the following water quality: turbidity 4.2 FTU, hardness 0.02 mmol / L, 2 mg / L in terms of calcium carbonate content, PH at 25 ℃ 8.5, dissolved oxygen 0.08 mg / L, oil 1.5 mg / L, and iron content 0.26 mg / L.

[0069] The pressure of the 160 ℃ dry saturated steam generated after the condensate water entering the steam supply device 21 is 0.65 MPa.

[0070] Then, the dry saturated steam generates hydrogen gas through the metal cracking water vapor hydrogen production module 4.

[0071] The dry saturated steam enters the metal cracking water vapor hydrogen production module 4, the dry saturated water vapor enters the steam cylinder II 41 with a pressure of 0.65-0.70 MPa, the steam cylinder II 41 distributes the steam to a plurality of cracking reaction devices 42 of the hydrogen production reaction system, the steam generates hydrogen gas containing a small amount of water vapor and condensate water through a series of chemical and electrochemical reactions with a metal cracking agent in the cracking reaction device 42 with a working temperature of 160-165 ℃ and a working pressure of 0.6-0.7 MPa, the hydrogen gas enters the condensation heat exchange device 45 to improve the purity of the hydrogen gas, the hydrogen gas enters the buffer tank 3 to stabilize the pressure and flow, the hydrogen gas with a working temperature of 35-45 ℃ and a pressure of 0.22-0.35 MPa is obtained, the purity of the hydrogen gas reaches ≥94%, the hydrogen gas with higher purity is obtained through the purification device 44, and the hydrogen gas is output through the conveying system.

[0072] In the metal cracking water vapor hydrogen production module 4, the dry saturated steam is sequentially passed through the steam cylinder II 41, the cracking reaction device 42, the condensation heat exchange device 45, the buffer tank 43 for stabilizing the pressure and flow, and the purification device 44.

[0073] The saturated water vapor entering the steam cylinder II 41 has a temperature of 164-170 ℃ and a pressure of 0.65-0.70 MPa, and the steam cylinder II 41 distributes the saturated water vapor to a plurality of cracking reaction devices 42 of the hydrogen production reaction system.

[0074] The working temperature of the cracking reaction device 42 is 160-165 DEG C, and the working pressure is 0.6-0.7, saturated water vapor and a series of chemical and electrochemical reactions of the metal cracking agent in the cracking reaction device 42 occur, hydrogen is generated, and the composition of the metal cracking agent includes aluminum, iron, manganese, carbon, NaCl and NaHSO4; at the same time, a series of displacement reactions, electrochemical reactions and redox reactions under other metal, metal compound and water and additional reaction conditions assist to generate hydrogen containing a small amount of water vapor.

[0075] The hydrogen containing a small amount of water vapor passes through the air cooling + water cooling heat exchange + gas-liquid separation of the condensation heat exchange system 45 to obtain hydrogen with a temperature of 30-55 DEG C and a pressure of 0.2-0.45 MPa;

[0076] The hydrogen generated by the condensation heat exchange system enters the transfer tank 43 to stabilize the pressure and flow, and hydrogen with a working temperature of 35-45 DEG C and a pressure of 0.22-0.35 MPa is obtained, the purity of the hydrogen is greater than or equal to 94%, and the hydrogen is output through a conveying system.

[0077] Since the block produced water in the embodiment has a salinity of 40181 mg / L, which is high salinity produced water, a multi-effect crystallization module 3 is arranged in the hydrogen production system.

[0078] The bottom concentrated liquid generated by the low-temperature evaporation device 24 and the steam supply device 21 passes through the evaporator 311 of the multi-effect evaporation crystallization device 31 to be generated into gas and concentrated liquid, the gas enters the condensation device 33 to be condensed and discharged, and the concentrated liquid is discharged from the lower end of the evaporator 311 into the crystallization tank 312, is discharged after crystallization, and is subjected to fine screening after the initial crystallization and precipitation of crystalline salt.

[0079] The steam supply device 21 and the multi-effect evaporation crystallization device 31 are connected in series with the steam cylinder I 32 having the functions of stabilizing the pressure and flow. One end of the steam cylinder I 32 is in communication with the steam output pipeline of the steam boiler or the steam generator 21, and the other end is in communication with the inlet of the evaporator 311.

[0080] The oil and gas field produced water hydrogen production process of the embodiment utilizes oil and gas field wastewater, waste heat and other resource conditions, effectively processes the produced water to produce hydrogen, and uses the hydrogen for hydrogen-mixed natural gas and coalbed gas output or boiler hydrogen-mixed combustion for oilfield heating systems, saves the amount of natural gas, reduces carbon emissions, and simultaneously maximizes water resource utilization, economic benefits and environmental protection. The integrated design of the hydrogen production system realizes the comprehensive utilization of block resources, and the modular design can meet the use requirements of different block working conditions, can increase or reduce modules according to special working conditions, effectively solves the problems of complex produced water treatment process, high treatment cost, large investment and environmental pollution, and realizes the minimization of environmental protection risks of oil and gas field stations.

[0081] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the patent claims.

Claims

1. An oil and gas field produced water hydrogen production process, comprising a water treatment module, a steam supply module, a metal cracking water steam hydrogen production module, and an auxiliary module; characterized in that: the produced water is treated by the physical oil removal and multi-layer filtration of the water treatment module, and the obtained clean water enters the steam supply module; the clean water successively passes through a low-temperature evaporation device and a steam supply device of the steam supply module, the working pressure of the low-temperature evaporation device is -0.08 to -0.15 MPa, and the temperature is 30 to 40℃, the steam after the clean water passes through the low-temperature evaporation device generates condensate water at the outlet under normal pressure, the 160℃ dry saturated steam generated by the steam supply device enters the metal cracking water steam hydrogen production module, and the concentrated liquid at the bottom of the low-temperature evaporation device and the steam supply device enters a multi-effect crystallization module; the dry saturated steam enters the metal cracking water steam hydrogen production module, and the dry saturated water steam enters a distribution cylinder with a pressure of 0.62 to 0.75 MPa, the steam is distributed to a plurality of cracking reaction devices of a hydrogen production reaction system by the distribution cylinder, the steam reacts with a metal cracking agent in the cracking reaction devices at a working temperature of 158 to 166℃ and a working pressure of 0.6 to 0.7 MPa to produce hydrogen containing a small amount of water vapor and condensate water, the hydrogen enters a condensing heat exchange device to improve the purity of the hydrogen, and the hydrogen successively enters a transfer tank and a purification device to obtain high-purity hydrogen.

2. The oil and gas field produced water hydrogen production process according to claim 1, characterized in that: the water treatment module adopts electromagnetic pulse sewage oil removal + filtration device, or electromagnetic pulse sewage oil removal device + graphene high-efficiency oil-water treatment device, or graphene oil-water treatment device to treat the produced water, and the obtained clean water has an oil content of ≤3 mg / l and a suspended solid content of ≤15 mg / l.

3. The oil and gas field produced water hydrogen production process according to claim 1, characterized in that: the condensate water at the outlet of the low-temperature evaporation device in the steam supply module has a turbidity of ≤5.0 FTU, a hardness of ≤0.03 mmol / L or a calcium carbonate content of ≤3 mg / L, a PH of 7.0 to 10.5 at 25℃, a dissolved oxygen content of ≤0.1 mg / L, an oil content of ≤2 mg / L, and an iron content of ≤0.3 mg / L; and the pressure of the 160℃ dry saturated steam generated after the condensate water enters the steam supply device is 0.65 MPa.

4. The oil and gas field produced water hydrogen production process according to claim 1, characterized in that: in the metal cracking water steam hydrogen production module, the dry saturated steam successively passes through a distribution cylinder, a cracking reaction device, a condensing heat exchange device, a pressure and flow stabilizing system, and a purification device, wherein: the saturated water steam entering the distribution cylinder has a temperature of 164 to 170℃ and a pressure of about 0.62 to 0.75 MPa, and the distribution cylinder distributes the saturated water steam to a plurality of cracking reaction devices of a hydrogen production reaction system. ​ ​ ​ ​ ​ ​ ​ ​ The working temperature of the cracking reaction device is 158-166 ℃, and the working pressure is 0.6-0.7 MPa; saturated water vapor reacts with metal cracking agents in the cracking reaction device to produce hydrogen, wherein the metal cracking agents comprise aluminum, iron, manganese, carbon, NaCl and NaHSO4; at the same time, a series of displacement reactions, electrochemical reactions and oxidation-reduction reactions under additional reaction conditions are assisted by other metals, metal compounds and water to produce hydrogen containing a small amount of water vapor.

5. The hydrogen production process of the oil and gas field produced water according to claim 4, characterized in that: The hydrogen containing a small amount of water vapor is subjected to air cooling + water cooling heat exchange + gas-liquid separation or water cooling heat exchange + gas-liquid separation through the condensation heat exchange system to obtain hydrogen with a temperature of 30-55 ℃ and a pressure of 0.2-0.45 MPa; The hydrogen produced by the condensation heat exchange system enters a transfer tank to obtain hydrogen with a temperature of 30-50 ℃ and a pressure of 0.18-0.40 MPa, and the purity of the hydrogen is ≥ 94%.

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