Electrolytic tank, wind-solar complementary electrolytic hydrogen production system and method for producing hydrogen through electrolysis of oilfield produced water

Abstract

The invention provides an electrolytic bath, a wind-solar complementary electrolytic hydrogen production system and an oil field produced water electrolysis hydrogen production method. The anode of the electrolytic bath is made of nickel-based alloy, the cathode of the electrolytic bath is made of nickel-based alloy, the pH value of electrolyte of the electrolytic bath is 13-14, and the electrolyte comprises alkali and 30-50 mg / L of imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor; the composite corrosion and scale inhibitor comprises 60-80% of imidazoline, 10-20% of Schiff base and 10-20% of pyridine; the nickel-based alloy metal comprises the following element components of 50%-60% of nickel, 10%-20% of chromium, 10%-20% of molybdenum and 10%-15% of iron. According to the electrolytic cell, the cathode and the anode which are made of specific materials are matched with the electrolyte of specific types, and hydrogen production through electrolysis of oilfield produced water can be effectively achieved.

Description

Technical Field

[0001] The present invention relates to an electrolyzer suitable for producing hydrogen by electrolysis of produced water in oil fields, a small-scale wind-solar complementary electrolysis hydrogen production system suitable for oil field stations, and a method for producing hydrogen by electrolysis of produced water in oil fields. Background Art

[0002] Existing water electrolysis hydrogen production systems generally have problems such as complex processes, large equipment scale, large footprint, high investment, and severe regional restrictions, making them unsuitable for use in oilfield stations.

[0003] Oilfield produced water is different from conventional water used for hydrogen production by electrolysis. It has complex composition, high mineralization, high calcium and magnesium ion content, etc. Common electrolytic cells for hydrogen production by water electrolysis have high requirements for raw water and cannot directly use oilfield produced water as raw material for hydrogen production by electrolysis. When using oilfield produced water as raw material for hydrogen production by electrolysis, additional water treatment equipment is usually required, which makes the hydrogen production system by water electrolysis more complicated and less suitable for use in oilfield stations.

[0004] In summary, it is currently necessary to research new electrolyzers and new electrolytic hydrogen production systems to meet the demand for direct electrolytic hydrogen production using oil field produced water as raw water in oil field stations. Summary of the invention

[0005] The object of the present invention is to provide an electrolytic cell capable of directly producing hydrogen by electrolysis using oilfield produced water as raw water, a small-scale electrolytic hydrogen production system suitable for use in oilfield stations, and a method for producing hydrogen by electrolysis of oilfield produced water suitable for oilfield stations.

[0006] In order to achieve the above objectives, the present invention provides the following three technical solutions.

[0007] In a first aspect, the present invention provides an electrolytic cell, wherein the material of the anode of the electrolytic cell is a nickel-based alloy, the material of the cathode of the electrolytic cell is a nickel-based alloy, and the electrolyte of the electrolytic cell comprises an imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and an alkali;

[0008] Wherein, based on the volume of the electrolyte, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L; based on the total mass of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor as 100%, the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor includes 60-80% of imidazoline, 10-20% of Schiff base, and 10-20% of pyridine;

[0009] Among them, the pH value of the electrolyte is 13-14;

[0010] The nickel-based alloy metal used as the material of the anode contains the following elemental components based on the total mass of the alloy metal as 100%: 50-60% nickel, 10-20% chromium, 10-20% molybdenum, and 10-15% iron (e.g., 56% nickel, 16% chromium, 16% molybdenum, and 12% iron);

[0011] Among them, the nickel-based alloy metal used as the cathode material contains the following elemental components based on the total mass of the alloy metal as 100%: 50-60% nickel, 10-20% chromium, 10-20% molybdenum, and 10-15% iron (56% nickel, 16% chromium, 16% molybdenum, and 12% iron).

[0012] The electrolyzer provided in the first aspect is an electrolyzer for producing hydrogen by electrolysis of produced water from oil fields, which can directly produce hydrogen by electrolysis using produced water from oil fields as raw water. By using cathodes and anodes made of specific materials in combination with specific types of electrolytes, hydrogen production by electrolysis of produced water from oil fields can be effectively achieved.

[0013] According to a preferred embodiment of the first aspect, the electrolytic cell includes a cell body and an anode, a cathode and an electrolyte arranged in the cell body, and the cell body is provided with an anode gas outlet, a cathode gas outlet and a raw water inlet; more preferably, the cell body is made of a polymer material or the cell body is coated with phenolic epoxy coating.

[0014] According to a preferred embodiment of the first aspect, a diaphragm is provided in the electrolytic cell, and the diaphragm is provided between the anode and the cathode.

[0015] According to a preferred embodiment of the first aspect, wherein the electrolyte comprises oilfield produced water;

[0016] Preferably, the mineralization of the produced water from the oil field is 1×10 4 -8×10 4 mg / L;

[0017] Preferably, based on the mass of the produced water from the oil field as 100%, the sodium ion concentration in the produced water from the oil field is 0.3×10 4 -3×10 4 mg / L, potassium ion concentration is 0.3×10 4 -3×10 4 mg / L, magnesium ion concentration is 100-700 mg / L, calcium ion concentration is 50-500 mg / L, crude oil content is ≤5.0 mg / L, suspended solid content is ≤1.0 mg / L; more preferably, the median particle size of the suspended solids is ≤1.0 μm;

[0018] Preferably, the solvent of the electrolyte is oilfield produced water;

[0019] Preferably, based on the mass of the electrolyte being 100%, the mass concentration of the oilfield produced water is 70-80%;

[0020] For example, the electrolyte can be obtained by mixing a mixture of imidazoline-Schiff base-pyridine composite corrosion inhibitor and oilfield produced water with an alkaline solution; wherein the alkaline solution can be obtained by mixing an alkali with oilfield produced water.

[0021] In a second aspect, the present invention provides a wind-solar complementary electrolysis hydrogen production system, wherein the system comprises:

[0022] Wind turbine, photovoltaic panel, wind-solar hybrid control inverter, electrolyzer provided in the first aspect, hydrogen purification unit, electrolyte storage unit;

[0023] Among them, the wind turbine and photovoltaic panel are respectively connected to the wind-solar complementary control inverter, and the wind-solar complementary control inverter is connected to the electrolyzer, so that the electricity generated by the wind turbine and photovoltaic panel is used to power the electrolyzer through the wind-solar complementary control inverter; the hydrogen purification part is connected to the electrolyzer, so that the hydrogen flow generated in the electrolyzer is purified by the hydrogen purification part to obtain high-purity hydrogen; the liquid outlet of the electrolyte storage part is connected to the electrolyzer, so as to supply electrolyte to the electrolyzer.

[0024] The wind-solar complementary electrolysis hydrogen production system provided by the present invention is a small-scale electrolysis hydrogen production system suitable for use in oil field stations. It can fully integrate the wind, light and oil field produced water resources of the oil field station to realize the preparation of hydrogen (the prepared hydrogen can be pressurized and stored and can also be used for combustion to provide heat in a heating furnace). It has a simple process flow, small equipment quantity, small footprint and low investment.

[0025] According to a preferred embodiment of the second aspect, the hydrogen purification unit includes a first cooler, a first gas-liquid separator and a scrubber connected in sequence, so that the hydrogen flow generated in the electrolyzer is first cooled by the first cooler, then enters the first gas-liquid separator for gas-liquid separation, and then enters the scrubber for scrubbing, and finally the purified high-purity hydrogen is discharged from the scrubber; in this preferred embodiment, the purity of the purified high-purity hydrogen discharged from the scrubber can reach 99.8%;

[0026] More preferably, the first gas-liquid separator is provided with a liquid replenishing port, and the liquid outlet of the scrubber and / or the liquid outlet of the electrolyte storage unit are connected to the liquid replenishing port of the first gas-liquid separator, so as to replenish the liquid phase for the first gas-liquid separator, so that when the liquid phase in the first gas-liquid separator drops below the lower limit of the liquid phase level, the scrubber and / or the electrolyte storage unit can be used to replenish the liquid;

[0027] More preferably, the liquid outlet of the electrolyte storage unit is connected to the scrubber, so that when the liquid phase in the scrubber drops below the lower limit of the liquid phase level, the electrolyte storage unit can be used to replenish the liquid phase;

[0028] More preferably, the gas outlet of the scrubber is connected to the raw material supply pipeline of the oilfield station heating furnace, so that the high-purity hydrogen discharged from the scrubber is supplied to the oilfield station heating furnace for combustion and heating; in this preferred embodiment, the wind, light and oilfield produced water resources of the oilfield station are integrated to realize the fuel supply of the oilfield station heating furnace, which helps to reduce the carbon emissions of the oilfield station;

[0029] More preferably, the first cooler is a swept fin tube air cooler, which uses ambient air outside the swept fin tube as a cooling medium to cool the high-temperature fluid in the swept fin tube;

[0030] More preferably, the liquid outlet of the first gas-liquid separator is connected to the electrolytic cell, so that when the liquid phase (electrolyte) in the first gas-liquid separator exceeds the upper limit of the liquid phase level, part of the liquid phase is returned to the electrolytic cell;

[0031] More preferably, the first gas-liquid separator can withstand a certain pressure;

[0032] More preferably, the scrubber can withstand a certain pressure;

[0033] More preferably, the feed port of the scrubber is arranged at the top of the scrubber, and a feed pipe connected to the feed port of the scrubber and extending to below the upper limit of the liquid level in the scrubber is arranged inside the scrubber; in this preferred embodiment, the gas discharged from the first gas-liquid separator enters from the feed port at the top of the scrubber, enters into the liquid phase inside the scrubber along the feed pipe to wash away the residual misty alkali solution and water vapor, and the washed gas is discharged through the gas outlet of the scrubber.

[0034] According to a preferred embodiment of the second aspect, the electrolyte storage unit includes a water tank and an alkali tank in parallel, and the liquid outlets of the water tank and the alkali tank are connected. The water tank is used to store a mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, and the alkali tank is used to store an alkali solution; more preferably, based on the volume of the mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L; more preferably, when the alkali is KOH, the mass concentration of the alkali is 20-30% based on the mass of the alkali solution as 100%. The size of the water tank can be adjusted according to the actual working conditions. For example, the size of the water tank is set to meet the amount of the mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor required for the normal operation of the electrolytic cell for 1 week. The size of the alkali tank can be adjusted according to the actual working conditions. For example, the size of the alkali tank is set to be able to store the amount of alkali solution required for the normal operation of the electrolytic cell for one week.

[0035] According to a preferred embodiment of the second aspect, the wind-solar complementary electrolysis hydrogen production system also includes a battery, which is connected to the wind-solar complementary control inverter, so that the surplus electricity generated by the wind turbine and photovoltaic panels exceeding the electricity used by the electrolyzer can be stored in the battery, and the electrolyzer can be powered when the electricity generated by the wind turbine and photovoltaic panels is insufficient to supply the electrolyzer.

[0036] According to a preferred embodiment of the second aspect, the wind-solar hybrid electrolysis hydrogen production system further includes an oxygen purification unit, which is connected to the electrolyzer, so as to purify the oxygen flow generated in the electrolyzer by the oxygen purification unit;

[0037] The oxygen purification unit includes a second cooler and a second gas-liquid separator connected in sequence, so that the oxygen flow generated in the electrolytic cell is first cooled by the second cooler and then enters the second gas-liquid separator for gas-liquid separation, and the purified oxygen is discharged from the second gas-liquid separator;

[0038] More preferably, the liquid outlet of the electrolyte storage unit is connected to the second gas-liquid separator to supply the second gas-liquid separator with liquid phase, and when the liquid phase in the second gas-liquid separator drops below the lower limit of the liquid phase level, the electrolyte storage unit can be used to replenish the liquid;

[0039] More preferably, the second cooler is a swept fin tube air cooler, which uses ambient air outside the swept fin tube as a cooling medium to cool the high-temperature fluid in the swept fin tube;

[0040] More preferably, the liquid outlet of the second gas-liquid separator is connected to the electrolytic cell, so that when the liquid phase (electrolyte) in the second gas-liquid separator exceeds the upper limit of the liquid phase level, part of the liquid phase is returned to the electrolytic cell;

[0041] More preferably, the second gas-liquid separator can withstand a certain pressure.

[0042] According to a preferred embodiment of the second aspect, a liquid replenishing pump is provided at the liquid outlet of the electrolyte storage part.

[0043] In a third aspect, the present invention provides a method for producing hydrogen by electrolysis of produced water from an oil field, wherein the method is performed using the electrolyzer provided in the first aspect, and the method comprises:

[0044] Using oilfield produced water to prepare the electrolyte used in the electrolytic cell provided in the first aspect;

[0045] The electrolyte is transported to the electrolytic cell provided in the first aspect to perform electrolysis to produce hydrogen.

[0046] The method provided in the third aspect of the present invention is a method suitable for producing hydrogen by electrolyzing oilfield produced water in an oilfield station.

[0047] According to a preferred embodiment of the third aspect, the step of using oilfield produced water to configure the electrolyte used in the electrolytic cell provided in the first aspect comprises:

[0048] The produced water from the oil field is mixed with a mixed solution of an imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and an alkaline solution in real time;

[0049] Preferably, based on the volume of the mixed solution of the oilfield produced water and the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L;

[0050] Preferably, when the alkali is KOH, the mass concentration of the alkali is 20%-30% based on the mass of the alkali solution being 100%;

[0051] In this preferred embodiment, the mixture of oilfield produced water, imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and alkaline solution can be mixed at a certain speed to obtain an electrolyte that meets the requirements.

[0052] According to a preferred embodiment of the third aspect, the method is performed using the wind-solar complementary electrolysis hydrogen production system provided by the second aspect; in this preferred embodiment, the method further includes:

[0053] Use wind turbines and photovoltaic panels to generate electricity, and use wind-solar hybrid control inverters to power electrolysis in electrolyzers;

[0054] The hydrogen gas purification unit purifies the hydrogen gas generated by the electrolytic cell to obtain high-purity hydrogen gas that can be used for combustion.

[0055] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0056] 1. The electrolyzer provided by the present invention can directly electrolyze and produce hydrogen using oilfield produced water as raw water, and the electrolysis efficiency reaches more than 80%.

[0057] 2. The wind-solar complementary electrolysis hydrogen production system provided by the present invention can fully integrate the wind, light and oilfield produced water resources of the oilfield station to realize the preparation of clean energy hydrogen that can replace fossil fuels, which helps to achieve energy conservation and consumption reduction, reduce carbon emissions and provide stable and continuous energy. At the same time, it alleviates the working pressure of the oilfield produced water treatment system, and can obtain excellent social and economic benefits in oilfield production.

[0058] 3. The wind-solar complementary electrolysis hydrogen production system provided by the present invention has a simple process flow, small equipment, small footprint, and low investment, which is in line with the actual limited footprint of land oil field stations.

[0059] 4. The hydrogen produced by the technical solution provided by the present invention is used as the fuel of the heating furnace of the oil field station to replace its original fuel oil and gas. According to the service life of the wind-solar complementary electrolysis hydrogen production system provided by the present invention is 20 years, the total carbon emissions of using oil and gas as fuel for 20 years is A tons, and the investment of the wind-solar complementary electrolysis hydrogen production system provided by the present invention is B yuan. The cost of using the hydrogen produced by the technical solution provided by the present invention as the fuel of the heating furnace of the oil field station to replace its original fuel oil and gas is controlled at B / A≤400 yuan / ton per ton of carbon, which can reduce the carbon emissions of fuel oil in the oil field heating furnace by 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic structural diagram of a wind-solar complementary electrolysis hydrogen production system provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0062] Example 1

[0063] This embodiment provides an electrolytic cell.

[0064] The electrolytic cell provided in this embodiment includes a cell body and an anode, a cathode and an electrolyte arranged in the cell body;

[0065] The tank body is provided with an anode gas outlet, a cathode gas outlet, a raw water inlet and an electrolyte inlet;

[0066] The material of the anode of the electrolytic cell is a nickel-based alloy, which contains the following elemental components based on the total mass of the alloy metal as 100%: 56% nickel, 16% chromium, 16% molybdenum, and 12% iron;

[0067] The cathode material of the electrolytic cell is a nickel-based alloy, which contains the following elemental components based on the total mass of the alloy metal as 100%: 56% nickel, 16% chromium, 16% molybdenum, and 12% iron;

[0068] The electrolyte of the electrolytic cell contains an imidazoline-Schiff base-pyridine composite corrosion inhibitor and an alkali; wherein, based on the volume of the electrolyte, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor is controlled at 30-50 mg / L; based on the total mass of the imidazoline-Schiff base-pyridine composite corrosion inhibitor as 100%, the imidazoline-Schiff base-pyridine composite corrosion inhibitor includes 60-80% of imidazoline, 10-20% of Schiff base, and 10-20% of pyridine; wherein the pH value of the electrolyte is 13-14.

[0069] Wherein, the tank body is coated with phenolic epoxy paint.

[0070] Wherein, a diaphragm is arranged in the electrolytic cell, and the diaphragm is arranged between the anode and the cathode.

[0071] The base is potassium hydroxide (KOH).

[0072] Wherein, based on the mass of the electrolyte being 100%, the electrolyte comprises oilfield produced water with a mass concentration of 70-80%;

[0073] The mineralization of the produced water from the oil field is 1×10 4 -8×10 4 mg / L; Taking the mass of oilfield produced water as 100%, the sodium ion concentration in the oilfield produced water is 0.3×10 4 -3×10 4 mg / L, potassium ion concentration is 0.3×10 4 -3×10 4 mg / L, magnesium ion concentration is 100-700mg / L, calcium ion concentration is 50-500mg / L, crude oil content is ≤5.0mg / L, suspended solids content is ≤1.0mg / L; the median particle size of suspended solids is ≤1.0μm.

[0074] Example 2

[0075] This embodiment provides a wind-solar complementary electrolysis hydrogen production system.

[0076] like Figure 1 As shown, the wind-solar complementary electrolysis hydrogen production system provided in this embodiment includes:

[0077] Wind turbine 1, photovoltaic panel 2, wind-solar hybrid control inverter 3, hydrogen purification unit 4, electrolyzer 5, electrolyte storage unit 6;

[0078] The electrolytic cell 5 is the electrolytic cell provided in Example 1;

[0079] The wind turbine 1 and the photovoltaic panel 2 are respectively connected to the wind-solar complementary control inverter 3, and the wind-solar complementary control inverter 3 is connected to the electrolyzer 5, so that the electricity generated by the wind turbine 1 and the photovoltaic panel 2 is used to power the electrolyzer 5 through the wind-solar complementary control inverter 3; the hydrogen purification unit 4 is connected to the cathode gas outlet of the electrolyzer 5, so that the hydrogen flow generated in the electrolyzer 5 is purified by the hydrogen purification unit 4 to obtain high-purity hydrogen; the first liquid outlet of the electrolyte storage unit 6 is connected to the electrolyzer 5, so that the electrolyte is supplied to the electrolyzer 5.

[0080] Among them, the hydrogen purification unit 4 includes a first cooler 41, a first gas-liquid separator 42 and a scrubber 43 which are connected in sequence, so that the hydrogen flow generated in the electrolytic cell 5 is first cooled by the first cooler 41, then enters the first gas-liquid separator 42 for gas-liquid separation, and then enters the scrubber 43 for washing, and finally the purified high-purity hydrogen is discharged from the scrubber 43.

[0081] Among them, the first gas-liquid separator 42 is provided with a liquid replenishing port, and the liquid outlet of the scrubber 43 is connected to the liquid replenishing port of the first gas-liquid separator 42, so as to replenish the liquid phase of the first gas-liquid separator 42, so that when the liquid phase in the first gas-liquid separator 42 drops below the lower limit of the liquid phase level, the scrubber 43 can be used to replenish the liquid.

[0082] Among them, the second liquid outlet of the electrolyte storage unit 6 is connected to the scrubber 43, so that when the liquid phase in the scrubber 43 drops below the lower limit of the liquid phase level, the electrolyte storage unit 6 can be used to replenish the liquid phase.

[0083] The gas outlet of the scrubber 43 is connected to the raw material supply pipeline of the oilfield station heating furnace, so that the high-purity hydrogen discharged from the scrubber is supplied to the oilfield station heating furnace for combustion and heating.

[0084] The first cooler 41 is a swept fin tube air cooler.

[0085] The liquid outlet of the first gas-liquid separator 42 is connected to the electrolytic cell 5, so that when the liquid phase (electrolyte) in the first gas-liquid separator 42 exceeds the upper limit of the liquid phase level, part of the liquid phase is returned to the electrolytic cell.

[0086] Among them, the first gas-liquid separator 42 can withstand a certain pressure;

[0087] Among them, the scrubber 43 can withstand a certain pressure.

[0088] Among them, the feed port of the scrubber 43 is arranged at the top of the scrubber 43, and a feed pipe connected to the feed port of the scrubber 43 and extending to below the upper limit of the liquid level in the scrubber 43 is arranged inside the scrubber 43. The gas discharged from the first gas-liquid separator 42 enters from the feed port at the top of the scrubber 43, enters into the liquid phase inside the scrubber 43 along the feed pipe to wash away the residual misty alkali solution and water vapor, and the washed gas is discharged through the gas outlet of the scrubber 43.

[0089] The electrolyte storage part 6 includes a water tank 61 and an alkali tank 62 connected in parallel, and the liquid outlets of the water tank 61 and the alkali tank 62 are connected. The water tank 61 is used to store a mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, and the alkali tank 62 is used to store an alkali solution (obtained by mixing alkali with oilfield produced water). Based on the volume of the mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L. The alkali is KOH, and the mass concentration of the alkali is 20-30% based on the mass of the alkali solution as 100%.

[0090] The size of the water tank 61 is adjusted according to the actual working conditions, and the size of the water tank is set to meet the amount of mixed liquid of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor required for the normal operation of the electrolytic cell for one week.

[0091] The size of the alkali tank 62 is adjusted according to the actual working conditions, and the size of the alkali tank is set to meet the amount of alkali solution required for storing the normal operation of the electrolytic cell for one week.

[0092] Among them, the wind-solar complementary electrolysis hydrogen production system also includes a battery 7, which is connected to the wind-solar complementary control inverter 3, so that the surplus electricity generated by the wind turbine 1 and the photovoltaic panel 2 that exceeds the electricity used by the electrolyzer 5 is stored in the battery 7, and the electrolyzer 5 is powered when the electricity generated by the wind turbine 1 and the photovoltaic panel 2 is insufficient to supply electricity to the electrolyzer 5.

[0093] Among them, the wind-solar complementary electrolysis hydrogen production system further includes an oxygen purification unit 8, which is connected to the anode gas exhaust port of the electrolyzer 5, so that the oxygen purification unit 8 is used to purify the oxygen flow generated in the electrolyzer 5; the oxygen purification unit 8 includes a second cooler 81 and a second gas-liquid separator 82 connected in sequence, so that the oxygen flow generated in the electrolyzer 5 is first cooled by the second cooler 81, and then enters the second gas-liquid separator 82 for gas-liquid separation, and the purified oxygen is discharged by the second gas-liquid separator 82.

[0094] Among them, the second liquid outlet of the electrolyte storage part 6 is connected to the second gas-liquid separator 82 to supply liquid to the second gas-liquid separator 82. When the liquid phase in the second gas-liquid separator 82 drops below the lower limit of the liquid phase level, the electrolyte storage part 6 can be used to replenish the liquid.

[0095] The second cooler 81 is a swept fin tube air cooler.

[0096] The liquid outlet of the second gas-liquid separator 82 is connected to the electrolytic cell 5 , so that part of the liquid phase (electrolyte) in the second gas-liquid separator 82 is returned to the electrolytic cell 5 when the liquid phase exceeds the upper limit of the liquid phase level.

[0097] The second gas-liquid separator 82 can withstand a certain pressure.

[0098] The first liquid outlet of the electrolyte storage unit 6 is provided with a first liquid replenishing pump 63 .

[0099] The second liquid outlet of the electrolyte storage unit 6 is provided with a second liquid replenishing pump 64 .

[0100] Example 3

[0101] This embodiment provides a method for producing hydrogen by electrolysis of oilfield produced water.

[0102] The method is performed using the wind-solar complementary electrolysis hydrogen production system provided in Example 2, and the method comprises:

[0103] Step S1: using oilfield produced water to prepare an electrolyte for use in the electrolytic cell provided in Example 1;

[0104] Step S2: transporting the electrolyte to the electrolytic cell provided in Example 1 to perform electrolysis to produce hydrogen.

[0105] Wherein, step S1 comprises:

[0106] The produced water from the oil field stored in the water tank 61 and the mixed solution of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor are mixed in real time with the alkaline solution stored in the alkali tank 62 at a certain speed to obtain the electrolyte used in the electrolytic cell provided in Example 1.

[0107] Wherein, the method for producing hydrogen by electrolysis of oilfield produced water also includes:

[0108] The wind turbine 1 and the photovoltaic panel 2 are used to generate electricity, and the wind-solar hybrid inverter is used to control the power supply for the electrolysis of the electrolyzer;

[0109] The surplus electricity generated by the wind turbine 1 and the photovoltaic panel 2 that exceeds the electricity used by the electrolytic cell 5 is stored in the storage battery 7, and is used to supply power to the electrolytic cell 5 when the electricity generated by the wind turbine 1 and the photovoltaic panel 2 is insufficient to supply the electricity used by the electrolytic cell 5.

[0110] Wherein, the method for producing hydrogen by electrolysis of oilfield produced water also includes:

[0111] The hydrogen gas purification unit 4 is used to purify the hydrogen gas flow generated by the electrolytic cell 5 to obtain high-purity hydrogen gas that can be used for combustion;

[0112] The high-purity hydrogen gas purified by the hydrogen purification unit 4 is supplied as fuel to the oil field heating furnace for combustion.

[0113] The method for producing hydrogen by electrolysis of produced water from an oil field further comprises: purifying the oxygen flow generated by the electrolytic cell 5 by using the oxygen purification unit 8 .

[0114] In a specific application, the electrolyte is obtained by mixing oilfield produced water with a mixture of imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and an alkaline solution; wherein the volume of the oilfield produced water is 1m 3 The content of imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor in the mixed solution of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L, the mass concentration of KOH in the alkaline solution is 30%, and the pH value of the obtained electrolyte is 13. Using this electrolyte for electrolysis to produce hydrogen can produce 1m 3 Hydrogen and 0.5m 3 Oxygen, power consumption 4kW·h. Among them, the oxygen produced by the electrolyzer is cooled by the second cooler 81 and then enters the second gas-liquid separator 82 for gas-liquid separation, the separated oxygen is discharged, and the separated electrolyte returns to the inlet of the first replenishment pump 63; the hydrogen produced by the electrolyzer is cooled by the first cooler 41 and then enters the first gas-liquid separator 42 for gas-liquid separation, the separated electrolyte returns to the inlet of the first replenishment pump 63, and the separated hydrogen enters the scrubber 43 and is washed with water to obtain hydrogen with a purity of 99.8%. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrolytic cell, wherein: The material of the anode of the electrolytic cell is a nickel-based alloy, the material of the cathode of the electrolytic cell is a nickel-based alloy, and the electrolyte of the electrolytic cell contains an imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and an alkali; Wherein, based on the volume of the electrolyte, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L; based on the total mass of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor as 100%, the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor includes 60-80% of imidazoline, 10-20% of Schiff base, and 10-20% of pyridine; Among them, the pH value of the electrolyte is 13-14; The nickel-based alloy metal used as the material of the anode contains the following element components based on the total mass of the alloy metal as 100%: 50-60% nickel, 10-20% chromium, 10-20% molybdenum, and 10-15% iron; The nickel-based alloy metal used as the cathode material contains the following element components based on the total mass of the alloy metal as 100%: 50-60% nickel, 10-20% chromium, 10-20% molybdenum, and 10-15% iron.

2. The electrolytic cell according to claim 1, wherein The electrolyte contains oilfield produced water. Taking the mass of the electrolyte as 100%, the mass concentration of the oilfield produced water is 70-80%.

3. The electrolytic cell according to claim 2, wherein: The mineralization of the produced water in the oil field is 1×10 4 -8×10 4 mg / L; Preferably, based on the mass of the produced water from the oil field as 100%, the sodium ion concentration in the produced water from the oil field is 0.3×10 4 -3×10 4 mg / L, potassium ion concentration is 0.3×10 4 -3×10 4 mg / L, magnesium ion concentration is 100-700mg / L, calcium ion concentration is 50-500mg / L, crude oil content ≤5.0mg / L, suspended solid content ≤1.0mg / L; More preferably, the median particle size of the suspended solids is ≤ 1.0 μm.

4. A wind-solar hybrid electrolysis hydrogen production system, wherein: The system includes: A wind turbine, a photovoltaic panel, a wind-solar hybrid control inverter, an electrolyzer according to any one of claims 1 to 3, a hydrogen purification unit, and an electrolyte storage unit; Among them, the wind turbine and photovoltaic panel are respectively connected to the wind-solar complementary control inverter, the wind-solar complementary control inverter is connected to the electrolyzer; the hydrogen purification part is connected to the electrolyzer; and the liquid outlet of the electrolyte storage part is connected to the electrolyzer.

5. The wind-solar hybrid electrolysis hydrogen production system according to claim 4, wherein: The hydrogen purification unit includes a first cooler, a first gas-liquid separator and a scrubber which are connected in sequence.

6. The wind-solar hybrid electrolysis hydrogen production system according to claim 5, wherein: The first gas-liquid separator is provided with a liquid replenishing port, and the liquid outlet of the scrubber and / or the liquid outlet of the electrolyte storage unit are connected to the liquid replenishing port of the first gas-liquid separator; The liquid outlet of the electrolyte storage unit is connected to the scrubber; The liquid outlet of the first gas-liquid separator is connected to the electrolytic cell.

7. The wind-solar hybrid electrolysis hydrogen production system according to claim 5, wherein: The gas outlet of the scrubber is connected to the raw material supply pipeline of the oil field station heating furnace.

8. The wind-solar hybrid electrolysis hydrogen production system according to claim 4, wherein: The electrolyte storage unit includes a water tank and an alkali tank connected in parallel, and the liquid outlets of the water tank and the alkali tank are connected. The water tank is used to store a mixture of oilfield produced water and imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor, and the alkali tank is used to store an alkali solution.

9. The wind-solar hybrid electrolysis hydrogen production system according to claim 4, wherein: The wind-solar hybrid electrolysis hydrogen production system also includes a battery, which is connected to the wind-solar hybrid control inverter.

10. The wind-solar hybrid electrolysis hydrogen production system according to claim 4, wherein: The wind-solar hybrid electrolysis hydrogen production system further includes an oxygen purification unit connected to the electrolyzer; wherein the oxygen purification unit includes a second cooler and a second gas-liquid separator connected in sequence.

11. The wind-solar hybrid electrolysis hydrogen production system according to claim 10, wherein: The liquid outlet of the electrolyte storage unit is connected to the second gas-liquid separator; The liquid outlet of the second gas-liquid separator is connected to the electrolytic cell.

12. A method for producing hydrogen by electrolysis of oilfield produced water, wherein: The method is carried out using the electrolytic cell according to any one of claims 1 to 3, and the method comprises: The electrolyte used in the electrolytic cell according to any one of claims 1 to 3 is prepared using oilfield produced water; The electrolyte is transported to the electrolytic cell according to any one of claims 1 to 3 for electrolytic hydrogen production.

13. The method according to claim 12, wherein: The step of using oilfield produced water to prepare the electrolyte used in the electrolytic cell provided in the first aspect comprises: The produced water from the oil field is mixed with a mixed solution of an imidazoline-Schiff base-pyridine composite corrosion and scale inhibitor and an alkaline solution in real time; Preferably, based on the volume of the mixed solution of the oilfield produced water and the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor, the content of the imidazoline-Schiff base-pyridine composite corrosion inhibitor and scale inhibitor is 30-50 mg / L; Preferably, when the alkali is KOH, based on the mass of the alkali solution being 100%, the mass concentration of the alkali is 20%-30%.

14. The method according to claim 12, wherein: The method is carried out using the wind-solar complementary electrolysis hydrogen production system described in any one of claims 4-11.

Images