A coupling system of SOEC hydrogen production and oil product hydrogenation

Abstract

This invention relates to a coupled system for SOEC hydrogen production and petroleum hydrotreating, comprising an SOEC hydrogen production unit and a petroleum hydrotreating unit. In the SOEC hydrogen production unit, pure water is vaporized in a steam generator to form steam, which is then electrolyzed in a fuel cell stack module to generate hydrogen. The mixture of hydrogen and steam is passed through a high-temperature heat exchanger on the hydrogen side to recover waste heat and preheat the steam. The separated hydrogen is then separated into reactive hydrogen and protective hydrogen by a booster compressor. The protective hydrogen is mixed with the steam and recycled. In the petroleum hydrotreating unit, the reactive hydrogen is mixed with the petroleum product to be hydrotreated and undergoes two heat exchanges. It is then connected to a high-temperature heat exchanger on the hydrogen side via a heat exchanger between the hydrogen production fuel side and the hydrotreating feedstock. Waste heat from hydrogen production is used to heat the mixed feedstock before it is passed into the hydrotreating reactor to complete the hydrotreating reaction. This invention uses green hydrogen to replace fossil fuel hydrogen production, achieving clean petroleum product decarbonization throughout its entire life cycle; and improves energy utilization efficiency through heat coupling.

Description

Technical Field

[0001] This invention relates to the field of clean energy, and more specifically to a coupling system for SOEC hydrogen production and oil hydrogenation. Background Technology

[0002] Hydrotreating is a core technology for producing clean fuels in modern oil refining. It involves reacting hydrogen with crude oil fractions (including gasoline, jet fuel, diesel, wax oil, heavy oil, etc.) under the action of a catalyst. This effectively removes harmful impurities such as sulfur, nitrogen, and oxygen from the oil and optimizes the molecular structure of hydrocarbons, thereby enabling the fuel to meet stringent global environmental standards such as China VI and Euro VI.

[0003] However, while current oil hydrotreating processes achieve cleaner fuels, they also face significant carbon emission challenges. This process consumes large amounts of hydrogen, accounting for over 95% of a refinery's total hydrogen consumption. Traditional methods of hydrogen production heavily rely on fossil fuels, primarily through natural gas steam reforming or coal-to-hydrogen processes; this type of hydrogen is known as "grey hydrogen" or "brown hydrogen." The fossil fuel-based hydrogen production process generates substantial carbon dioxide emissions, making oil hydrotreating a significant source of carbon emissions for the refining industry. Summary of the Invention

[0004] To address the issues of high carbon emissions from traditional petroleum hydrogenation relying on fossil fuels and low energy efficiency due to the lack of coordinated utilization of heat from hydrogen production and refueling, this invention aims to provide a coupled system for SOEC hydrogen production and petroleum hydrogenation.

[0005] The SOEC hydrogen production and oil hydrotreating coupling system according to the present invention includes an SOEC hydrogen production unit and an oil hydrotreating unit. The SOEC hydrogen production unit includes a steam generator, a fuel cell stack module, a hydrogen-side high-temperature heat exchanger, and a hydrogen booster. Pure water is vaporized in the steam generator to form steam, which is then electrolyzed in the fuel cell stack module to generate hydrogen. The hydrogen and steam mixture generated by the fuel cell stack module is introduced into the hydrogen-side high-temperature heat exchanger. The hydrogen-side high-temperature heat exchanger is used to recover the high-temperature waste heat from the hydrogen and steam mixture to preheat the steam and hydrogen mixture entering the fuel cell stack module. The separated hydrogen is partially introduced into the oil hydrotreating unit as reactive hydrogen by the hydrogen booster, and the remaining portion forms protective hydrogen which is vaporized in the steam generator to form... After being mixed with water vapor, the mixture enters the high-temperature heat exchanger on the hydrogen side. The oil hydrotreating unit includes a heat exchanger for hydrotreating products and feedstocks, a heat exchanger for hydrogen production fuel-side products and hydrotreating feedstocks, and a hydrotreating reactor. The reacting hydrogen and the oil to be hydrotreating are mixed and then undergo preliminary heat exchange through the heat exchanger for hydrotreating products and feedstocks before entering the heat exchanger for hydrogen production fuel-side products and hydrotreating feedstocks. The heat exchanger for hydrogen production fuel-side products and hydrotreating feedstocks is connected to the high-temperature heat exchanger on the hydrogen side. The high-temperature waste heat from the hydrogen-side products of the hydrogen production unit is used to further heat the mixture of reacting hydrogen and the oil to be hydrotreating feedstock after the preliminary heat exchange, achieving heat coupling between the SOEC hydrogen production unit and the oil hydrotreating unit. The heated mixture is then fed into the hydrotreating reactor to complete the oil hydrotreating reaction.

[0006] In a preferred embodiment, when the oil to be processed is a heavy oil, the oil hydrogenation unit further includes a heating furnace, and the mixed feedstock from the hydrogen fuel side product and the hydrogenation feedstock heat exchanger is further heated before entering the hydrogenation reactor.

[0007] In a preferred embodiment, when the oil to be hydrogenated is a light oil, the energy input terminal of the steam generator is connected to renewable energy power; when the oil to be hydrogenated is a heavy oil, the convection section of the heating furnace is connected to the steam generator to provide a heat source for pure water gasification.

[0008] In a preferred embodiment, the operating temperature of the fuel cell stack module is 700-900℃, preferably 750-850℃; when the oil to be processed is a light oil, the reaction temperature of the hydrogenation reactor is 200-300℃; when the oil to be processed is a heavy oil, the reaction temperature of the hydrogenation reactor is 300-400℃.

[0009] In a preferred embodiment, when the oil to be processed is heavy crude oil, the heat exchange sequence between the hydrogenation product and the feedstock heat exchanger and between the hydrogen production fuel-side product and the hydrogenation feedstock heat exchanger is adjusted to achieve cascade utilization and recovery of heat.

[0010] In a preferred embodiment, the SOEC hydrogen production unit further includes a hydrogen-side electric heater disposed between the hydrogen-side high-temperature heat exchanger and the fuel cell module, used to further heat the water vapor and hydrogen mixture preheated by the hydrogen-side high-temperature heat exchanger to the operating temperature required for the fuel cell module to electrolyze and produce hydrogen; the SOEC hydrogen production unit also includes a blower, an air-side high-temperature heat exchanger, and an air-side electric heater connected in series, wherein air is connected to the air-side high-temperature heat exchanger through the blower, the air-side high-temperature heat exchanger recovers the waste heat carried by the oxygen-enriched air discharged after the fuel cell module reaction, and uses this waste heat to preheat the ambient temperature air delivered by the blower; the air-side electric heater further heats the air preheated by the air-side high-temperature heat exchanger to the operating temperature required for the fuel cell module to electrolyze and produce hydrogen.

[0011] In a preferred embodiment, the SOEC hydrogen production unit further includes a cooler and a gas-liquid separator connected in series between the hydrogen fuel-side product heat exchanger and the hydrogen feedstock heat exchanger. The cooler cools the hydrogen and water vapor mixture after the waste heat is released from the hydrogen fuel-side product heat exchanger and the hydrogen feedstock heat exchanger. The gas-liquid separator is used to separate the cooled hydrogen and water vapor mixture into liquid and gas. The separated liquid water is discharged as wastewater, while the purified hydrogen is fed into the hydrogen booster to form reactive hydrogen.

[0012] In a preferred embodiment, the oil hydrotreating unit further includes a cooler, an oil-gas separator, and a circulating hydrogen compressor connected in series downstream of the heat exchanger between the hydrotreating product and the feedstock. The cooler further cools the hydrotreating product after initial heat exchange in the heat exchanger between the hydrotreating product and the feedstock. The gas phase outlet of the oil-gas separator is connected to the circulating hydrogen compressor to perform gas-liquid separation on the cooled hydrotreating product. The output of the circulating hydrogen compressor is divided into two paths: one path is connected back to the heat exchanger between the hydrotreating product and the feedstock, and the other path is connected back to the hydrotreating reactor to regulate the temperature of the hydrotreating reactor.

[0013] In a preferred embodiment, the output end of the circulating hydrogen compressor is provided with a waste hydrogen discharge branch. When the circulating hydrogen concentration is lower than a preset concentration, the purity of the circulating hydrogen is maintained by discharging waste hydrogen.

[0014] In a preferred embodiment, the oil hydrotreating unit further includes a fractionation tower, and the liquid phase outlet of the oil-gas separator is connected to the fractionation tower to output the hydrotreated oil product.

[0015] The present invention has the following advantages:

[0016] 1) By using renewable energy electricity to convert water into green hydrogen through the SOEC hydrogen production unit, a zero-carbon hydrogen source is provided for the oil hydrogenation reaction, which completely replaces the traditional hydrogen production method that relies on fossil energy. This eliminates carbon emissions in the oil hydrogenation process from the source, realizes low-carbon and environmentally friendly clean oil throughout its entire life cycle, and effectively responds to the needs of the refining and chemical industry for decarbonization and transformation.

[0017] 2) Through the thermal coupling design between the hydrogen production and hydrogenation units, the high-temperature waste heat generated during the SOEC hydrogen production process is efficiently recovered and used to heat the mixed feedstock for the hydrogenation reaction. The highly thermally coupled process system design is suitable for the hydrogenation process of different oil products, which greatly reduces additional energy consumption and significantly improves the overall energy utilization efficiency of the system.

[0018] 3) In addition, converting fluctuating renewable energy power into stable and storable green hydrogen chemical energy not only solves the problem of renewable energy consumption, but also provides a continuous and stable hydrogen source guarantee for oil hydrogenation. Protecting the rational allocation and reuse of hydrogen and recycled hydrogen further improves the utilization rate of hydrogen resources, ensures the efficient and stable operation of hydrogen production and hydrogenation processes, and realizes the synergistic optimization of energy production and chemical processing. Attached Figure Description

[0019] Figure 1 This is a coupling system for SOEC hydrogen production and light oil hydrogenation according to the present invention.

[0020] Figure 2 This is the SOEC hydrogen production and heavy oil hydrogenation coupling system 1 according to the present invention.

[0021] Figure 3 This is the SOEC hydrogen production and heavy oil hydrogenation coupling system 2 according to the present invention. Detailed Implementation

[0022] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0023] Solid oxide electrolyzers (SOECs) offer superior energy efficiency and zero carbon emissions for hydrogen production. Compared to traditional alkaline electrolyzers or proton exchange membrane electrolyzers, SOEC technology operates at temperatures as high as 700-900°C, directly and efficiently decomposing water vapor into hydrogen and oxygen using electrical energy. This high-temperature environment significantly reduces the energy consumption of the electrolysis reaction. Furthermore, its high-temperature operation allows for efficient integration of external heat sources (such as industrial waste heat), further optimizing the energy consumption structure and effectively reducing hydrogen production costs. Moreover, the electricity consumed in SOEC hydrogen production can be derived from renewable energy sources such as wind and solar power, resulting in hydrogen produced as "green hydrogen," fundamentally avoiding carbon emissions during the hydrogen production process. This invention couples SOEC hydrogen production technology with oil hydrotreating processes, generating significant synergistic benefits and possessing both important technological and environmental significance: First, it enables complete decarbonization of refinery hydrogen sources, eliminating carbon emissions from the oil hydrotreating process that rely on fossil fuel hydrogen production, ensuring that clean oil products truly meet "clean" standards throughout their entire lifecycle; Second, it achieves efficient energy integration, as the high-temperature waste heat generated during SOEC hydrogen production can be matched with the energy demands of the oil hydrotreating unit, achieving rational heat utilization and improving the overall system energy efficiency; Third, it effectively solves the problem of renewable energy absorption. Renewable energy sources such as wind and solar power are highly volatile; SOEC hydrogen production technology can convert this unstable electricity into stable, storable chemical energy (green hydrogen), ensuring a stable supply of hydrogen for oil hydrotreating processes and providing a new pathway for the large-scale application of renewable energy.

[0024] The SOEC hydrogen production and oil hydrogenation coupling system according to the present invention includes an SOEC hydrogen production unit and an oil hydrogenation unit. The hydrogen output of the SOEC hydrogen production unit is connected to the hydrogen input of the oil hydrogenation unit via pipelines, providing green hydrogen to the oil hydrogenation unit. The SOEC hydrogen production unit and the oil hydrogenation unit achieve heat coupling to match the high-temperature waste heat generated by the SOEC hydrogen production unit with the feedstock heating requirements of the oil hydrogenation unit. Specifically, the SOEC hydrogen production unit is directly driven by renewable energy electricity, converting fluctuating wind and solar power into stable and storable green hydrogen chemical energy. This solves the problem of renewable energy consumption and provides a stable hydrogen source for oil hydrogenation, achieving synergy between energy and chemical industries. Thus, the present invention utilizes renewable energy electricity to produce green hydrogen through the SOEC hydrogen production unit, directly supplying hydrogen to the oil hydrogenation unit, replacing traditional fossil fuel-based hydrogen production (grey hydrogen / brown hydrogen), eliminating carbon emissions from the oil hydrogenation process at its source, and achieving clean oil decarbonization throughout its entire life cycle.

[0025] The SOEC hydrogen production unit is the core of green hydrogen production, used to convert renewable energy electricity into chemical energy (hydrogen), while also providing high-temperature waste heat for the oil hydrotreating unit, such as... Figure 1As shown, it specifically includes a blower 2, a steam generator 3, an air-side high-temperature heat exchanger 4, an air-side electric heater 5, an electric stack module 6, a hydrogen-side high-temperature heat exchanger 7, a hydrogen-side electric heater 8, a cooler 10, a gas-water separator 11, and a hydrogen booster 12.

[0026] Steam generator 3, serving as the water vaporization component in SOEC hydrogen production, has pure water A introduced into its inlet via a pipeline to generate superheated steam. The steam output of steam generator 3 is connected to the feed inlet of the high-temperature heat exchanger 7 on the hydrogen side via a pipeline, forming a superheated steam delivery channel. Furthermore, the energy input of steam generator 3 can be adaptively matched according to the type of oil being coupled. For example... Figure 1 As shown, the energy input terminal of the steam generator 3 is a power supply terminal connected to the renewable energy power source 1. For example... Figure 2 As shown, the energy input of the steam generator 3 is the heat from the convection section of the oil hydrogenation unit heater 19, which will be discussed in detail later.

[0027] Blower 2 serves as an air delivery power component. Its air inlet is connected to air B, and its output end is connected to the air inlet of the high-temperature heat exchanger 4 on the air side through a pipeline, serving as the purge air for the air side of the fuel cell module 6.

[0028] The air-side high-temperature heat exchanger 4 serves as an air preheating and waste heat recovery component. Its air inlet is connected to the output end of the blower 2, and its air outlet is connected to the inlet of the air-side electric heater 5 through a pipeline. At the same time, the waste heat recovery inlet of the air-side high-temperature heat exchanger 4 is connected to the air-side outlet of the fuel cell module 6 to cool the oxygen-enriched air J discharged from the fuel cell module 6, thereby achieving preheating and energy saving of the purge air.

[0029] The air-side electric heater 5 serves as the final air heating component. Its inlet is connected to the air outlet of the air-side high-temperature heat exchanger 4, and its outlet is connected to the air-side inlet of the fuel cell stack module 6 through a pipeline. It is used to further heat the preheated air to 750°C (the operating temperature of the fuel cell stack module 6).

[0030] The hydrogen-side high-temperature heat exchanger 7 serves as a component for steam-hydrogen mixing preheating and hydrogen production product waste heat recovery. Its steam inlet is connected to the steam output end of the steam generator 3 (with protective hydrogen mixed in the steam), and its steam outlet is connected to the inlet of the hydrogen-side electric heater 8 through a pipeline to preheat the mixed steam to about 500°C. At the same time, the waste heat recovery inlet of the hydrogen-side high-temperature heat exchanger 7 is connected to the fuel-side outlet of the fuel cell module 6 to absorb the high-temperature waste heat of the hydrogen-water vapor mixture discharged from the fuel cell module 6, thereby achieving steam-side raw material preheating.

[0031] The hydrogen-side electric heater 8 serves as the final steam heating component. Its inlet is connected to the steam outlet of the hydrogen-side high-temperature heat exchanger 7, and its outlet is connected to the fuel-side inlet of the fuel cell stack module 6 via a pipeline. It is used to further heat the preheated superheated steam (including protective hydrogen) to 750°C.

[0032] The fuel cell module 6, serving as the core reaction component for hydrogen production, has its air-side inlet connected to the outlet of the air-side electric heater 5, and its air-side outlet connected to the waste heat recovery inlet of the air-side high-temperature heat exchanger 4. After the reaction, oxygen-enriched air J is discharged. Its fuel-side inlet is connected to the outlet of the hydrogen-side electric heater 8, and its fuel-side outlet is connected to the waste heat recovery inlet of the hydrogen-side high-temperature heat exchanger 7. After the reaction, a hydrogen-water vapor mixture is discharged. Additionally, the power supply terminal of the fuel cell module 6 is connected to renewable energy source 1 to obtain the electricity required for electrolysis. Under the action of direct current, at the cathode / electrolyte interface of the individual cells in the fuel cell module 6, water vapor combines with electrons flowing in from the external circuit, undergoing a reduction reaction to generate H2 and O. 2- O 2- Driven by an applied direct current, the electrolyte diffuses from the cathode of the electrolytic cell through the electrolyte to the electrolyte / anode interface, where O 2- It loses electrons and undergoes an oxidation reaction to produce O2.

[0033] Cooler 10 serves as a cooling component for hydrogen production products. Its inlet is connected to the mixture outlet of the high-temperature heat exchanger 7 on the hydrogen side via a heat coupling unit and pipeline (after the hydrogen-water vapor mixture releases waste heat). Chilled water is introduced into the cooling medium inlet to cool the mixture to about 20°C.

[0034] The gas-liquid separator 11 serves as a gas-liquid separation component. Its inlet is connected to the outlet of the cooler 10. The liquid phase outlet discharges wastewater K through a pipeline, and the gas phase outlet is connected to the inlet of the hydrogen booster 12 through a pipeline, thereby achieving the separation of hydrogen and water.

[0035] The hydrogen booster 12 serves as a hydrogen booster and diversion component. Its inlet is connected to the gas phase outlet of the gas-water separator 11, and its output is divided into two paths: one path is connected back to the steam transmission pipeline between the steam generator 3 and the hydrogen-side high-temperature heat exchanger 7 through a pipeline to provide protective hydrogen for SOEC hydrogen production; the other path is connected to the oil hydrogenation unit through a pipeline to provide reactive hydrogen D for oil hydrogenation.

[0036] The oil hydrotreating unit is used to achieve desulfurization, denitrification, deoxygenation, and hydrocarbon molecular structure optimization of oils. When processing light-type oils, such as... Figure 1 As shown, it specifically includes a heat exchanger 9 for hydrogen production fuel-side products and hydrogenation feedstock, a heat exchanger 13 for hydrogenation products and feedstock, a hydrogenation reactor 14, a cooler 15, an oil-gas separator 16, a circulating hydrogen compressor 17, and a fractionation tower 18. When processing heavy oil products, such as... Figure 2As shown, an additional heating furnace 19 is included.

[0037] The hydrogenation product and feedstock heat exchanger 13 serves as a heat exchange component for preheating the hydrogenation feedstock and cooling the hydrogenation product. Its feedstock inlet has three flow paths: one path leads to the oil to be processed (such as...). Figure 1 Light petroleum products C, such as gasoline or jet fuel, or such as Figure 2 The heavy oil product L, such as diesel or wax oil, is connected in one direction to the output of the circulating hydrogen compressor 17 (circulating hydrogen circuit), and in another direction to the green hydrogen output of the hydrogen booster 12 (green hydrogen supply circuit). The three fluids converge to form a mixed feedstock. The product inlet of the hydrogenation product and feedstock heat exchanger 13 is connected to the outlet of the hydrogenation reactor 14 to recover the waste heat of the hydrogenation product and preheat the feedstock. The product outlet of the hydrogenation product and feedstock heat exchanger 13 is connected to the inlet of the cooler 15 through a pipeline.

[0038] The feed inlet of the hydrogen fuel-side product and hydrogen feedstock heat exchanger 9 is connected to the feedstock outlet of the hydrogen product and feedstock heat exchanger 13. The feedstock outlet is adapted to the oil type: in such cases... Figure 1 When processing light oil products, it is directly connected to the inlet of the hydrotreating reactor 14; in the case of... Figure 2 When processing heavy oil products, the process is connected to the inlet of the heater 19; the heat source inlet of the hydrogen fuel-side product and hydrogen feedstock heat exchanger 9 is connected to the mixture outlet of the hydrogen-side high-temperature heat exchanger 7 to recover the high-temperature waste heat of SOEC hydrogen production products and achieve preheating of hydrogen feedstock; the heat source outlet of the hydrogen fuel-side product and hydrogen feedstock heat exchanger 9 is connected to the inlet of the cooler 10, so that the mixture of hydrogen-side high-temperature heat exchanger 7 at about 100~150°C after releasing waste heat enters the cooler 10 for cooling. Specifically, the heat exchanger 9 for hydrogen fuel-side products and hydrogenation feedstock is a universal core heat exchange element used in coupling with both light and heavy oil hydrogenation. One side of its flow channel is fed with a hydrogen-water vapor mixture (approximately 250-350°C, releasing high-temperature waste heat) discharged from the SOEC hydrogen production unit, while the other side is fed with the mixed feedstock from the oil hydrogenation unit (light oil requires heating to 200-300°C, heavy oil requires initial heating). This counter-current heat exchange allows for direct recovery of high-temperature waste heat, replacing the traditional combustion furnace preheating stage (for light oil) or auxiliary preheating stage (for heavy oil) in hydrogenation processes. Specifically, such as... Figure 3 As shown, when processing heavy oil products, the heat exchange sequence of the hydrogenation product and feedstock heat exchanger 13 and the hydrogen production fuel-side product and hydrogenation feedstock heat exchanger 9 can also be adjusted to achieve cascade utilization and recovery of heat.

[0039] like Figure 2The heavy oil-specific heater 19 shown serves as a heating and heat replenishment component. Its inlet is connected to the feed outlet of the hydrogen fuel-side product and hydrogen feedstock heat exchanger 9, and its outlet is connected to the inlet of the hydrogenation reactor 14. It is used to heat the heavy oil-hydrogen mixture to 300-400°C. The convection section of the heater 19 is connected to the steam generator 3 of the SOEC hydrogen production unit through a pipeline to provide a heat source for the gasification of pure water A. Specifically, the heater 19 is a dedicated heat matching element for heavy oil coupling. Its core improvement lies in "tiered utilization of heat": the radiant section (high-temperature section) of the heater 19 is used to heat the heavy oil-hydrogen mixture to the required 300-400℃ for the reaction, while the convection section (low-temperature section) is connected to the steam generator 3 of the SOEC hydrogen production unit through pipelines. The waste heat of the convection section is used to provide a heat source for the gasification of pure water A, replacing the renewable energy-driven gasification method in the light oil scenario. This achieves tiered energy use of "high-temperature heating of oil and medium-temperature gasification of pure water", reducing the power consumption of the hydrogen production unit.

[0040] Thus, for the hydrogenation reaction temperature of light oil products (200-300℃), this invention utilizes the high-temperature waste heat of 250-350℃ from SOEC hydrogen production to directly heat the hydrogenation feedstock through the hydrogen fuel-side product and hydrogenation feedstock heat exchanger 9, eliminating the need for a combustion furnace in traditional hydrogenation processes and reducing system energy consumption. For the hydrogenation reaction temperature of heavy oil products (300-400℃), this invention incorporates a heating furnace 19 to meet the high-temperature requirements. Simultaneously, the waste heat from the convection section of the heating furnace is used to power the pure water gasification of SOEC hydrogen production, replacing electric gasification, achieving cascaded utilization of heat, and improving overall energy utilization efficiency.

[0041] Hydrogenation reactor 14, as the core component of the oil hydrogenation reaction, has its inlet adapted to the oil type: (e.g.) Figure 1 When processing light oil products, the process is connected to the feed outlet of the heat exchanger 9 between the hydrogen fuel side product and the hydrogenation feedstock; in the case of... Figure 2 When processing heavy oil products, it is connected to the outlet of the heating furnace 19; the reaction temperature of the hydrogenation reactor 14 is controlled by the heat source (200-300℃ for light oil products, 300-400℃ for heavy oil products), and desulfurization, denitrification, deoxygenation and hydrocarbon molecular structure optimization reactions occur inside. The outlet is connected to the product inlet of the hydrogenation product and the feed heat exchanger 13.

[0042] Cooler 15 serves as a cooling component for the hydrogenation product. Its inlet is connected to the product outlet of the heat exchanger 13 between the hydrogenation product and the raw material. Cooling medium is introduced into the cooling medium inlet to cool the hydrogenation product to about 40°C. Its outlet is connected to the inlet of the oil-gas separator 16 through a pipeline.

[0043] The oil-gas separator 16 serves as a gas-liquid separation component. Its inlet is connected to the outlet of the cooler 15, its liquid phase outlet is connected to the inlet of the fractionation tower 18 via a pipeline, and its gas phase outlet is connected to the inlet of the circulating hydrogen compressor 17 via a pipeline (the gas phase contains circulating hydrogen and a small amount of C1~C2 hydrocarbons).

[0044] The circulating hydrogen compressor 17, serving as a circulating hydrogen booster, has its inlet connected to the gas phase outlet of the oil-gas separator 16. Its output end is equipped with a waste hydrogen F discharge branch. When the circulating hydrogen concentration is below 85%, the concentration is maintained by discharging waste hydrogen. Additionally, the circulating hydrogen compressor 17 outputs circulating hydrogen E from the hydrogenation unit. This E is divided into two paths: one path connects back to the feedstock inlet pipeline of the hydrogenation product and feedstock heat exchanger 13, where it is mixed with fresh feedstock for recycling; the other path connects back to the interbed cooling pipeline of the hydrogenation reactor 14 for cooling the interbed of the hydrogenation reactor.

[0045] Thus, the present invention relates to a dual circulation loop of "protected hydrogen reflux and recycled hydrogen reuse": the green hydrogen output from the hydrogen booster 12 is partially refluxed as protective hydrogen for SOEC hydrogen production, and the recycled hydrogen output from the recycled hydrogen compressor 17 is partially reused for raw material mixing and partially used for reactor bed cooling. Furthermore, the recycled hydrogen concentration is controlled (≥85%) by waste hydrogen discharge to ensure stable system operation.

[0046] The fractionation tower 18 serves as a component for separating and purifying finished oil products. Its inlet is connected to the liquid phase outlet of the oil-gas separator 16, and it outputs hydrogenated dry gas G and finished oil H that meet environmental protection standards (China VI, Euro VI) from the top of the tower or from the side.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A coupling system for SOEC hydrogen production and oil hydrotreating, characterized in that, The coupled system includes an SOEC hydrogen production unit and an oil hydrotreating unit; The SOEC hydrogen production unit includes a steam generator (3), a fuel cell module (6), a hydrogen-side high-temperature heat exchanger (7), and a hydrogen booster (12). Pure water is vaporized by the steam generator (3) to form steam, and then electrolyzed in the fuel cell module (6) to generate hydrogen. The mixture of hydrogen and steam generated by the fuel cell module (6) is introduced into the hydrogen-side high-temperature heat exchanger (7). The hydrogen-side high-temperature heat exchanger (7) is used to recover the high-temperature waste heat in the mixture of hydrogen and steam to preheat the mixture of steam and hydrogen entering the fuel cell module (6). The separated hydrogen is partially converted into reactive hydrogen (D) by the hydrogen booster (12) and introduced into the oil hydrotreating unit. The other part is converted into protective hydrogen and mixed with the steam generated by the steam generator (3) before entering the hydrogen-side high-temperature heat exchanger (7). The oil hydrogenation unit includes a hydrogenation product and feedstock heat exchanger (13), a hydrogen fuel-side product and hydrogenation feedstock heat exchanger (9), and a hydrogenation reactor (14). The reacting hydrogen (D) is mixed with the oil to be hydrogenated (C) and then undergoes preliminary heat exchange through the hydrogenation product and feedstock heat exchanger (13) before entering the hydrogen fuel-side product and hydrogenation feedstock heat exchanger (9). The hydrogen fuel-side product and hydrogenation feedstock heat exchanger (9) is connected to the hydrogen-side high-temperature heat exchanger (7). The high-temperature waste heat of the hydrogen-side product of the hydrogen production unit is used to further heat the mixed feedstock of the reacting hydrogen (D) and the oil to be hydrogenated (C) after preliminary heat exchange, thereby realizing the heat coupling utilization of the SOEC hydrogen production unit and the oil hydrogenation unit. The heated mixed feedstock is then fed into the hydrogenation reactor (14) to complete the oil hydrogenation reaction.

2. The coupling system according to claim 1, characterized in that, When the oil to be processed is a heavy oil, the oil hydrogenation unit also includes a heating furnace (19), and the mixed feedstock from the hydrogen fuel side product and the hydrogenation feedstock heat exchanger (9) is further heated before entering the hydrogenation reactor (14).

3. The coupling system according to claim 2, characterized in that, When the oil to be hydrogenated is a light oil, the energy input end of the steam generator (3) is connected to renewable energy power; when the oil to be hydrogenated is a heavy oil, the convection section of the heater (19) is connected to the steam generator (3) to provide a heat source for pure water gasification.

4. The coupling system according to claim 1, characterized in that, The operating temperature of the fuel cell stack module (6) is 700-900℃. When the oil to be processed is light oil, the reaction temperature of the hydrogenation reactor (14) is 200-300℃. When the oil to be processed is heavy oil, the reaction temperature of the hydrogenation reactor (14) is 300-400℃.

5. The coupling system according to claim 1 or 4, characterized in that, When the oil to be processed is heavy crude oil, the heat exchange sequence of the hydrogenation product and feedstock heat exchanger (13) and the hydrogen production fuel side product and hydrogenation feedstock heat exchanger (9) is adjusted to achieve the cascade utilization and recovery of heat.

6. The coupling system according to claim 1, characterized in that, The SOEC hydrogen production unit also includes a hydrogen-side electric heater (8) disposed between the hydrogen-side high-temperature heat exchanger (7) and the fuel cell module (6), used to further heat the water vapor and hydrogen mixture preheated by the hydrogen-side high-temperature heat exchanger (7) to the working temperature required for the fuel cell module (6) to electrolyze hydrogen; the SOEC hydrogen production unit also includes a blower (2), an air-side high-temperature heat exchanger (4) and an air-side electric heater (5) connected in series, wherein air is connected to the air-side high-temperature heat exchanger (4) through the blower (2), the air-side high-temperature heat exchanger (4) recovers the waste heat carried by the oxygen-enriched air discharged after the reaction of the fuel cell module (6), and uses the waste heat to preheat the room temperature air delivered by the blower (2); the air-side electric heater (5) further heats the air preheated by the air-side high-temperature heat exchanger (4) to the working temperature required for the fuel cell module (6) to electrolyze hydrogen.

7. The coupling system according to claim 1, characterized in that, The SOEC hydrogen production unit also includes a cooler (10) and a gas-liquid separator (11) connected in series between the hydrogen production fuel-side product and hydrogen feedstock heat exchanger (9) and the hydrogen booster (12). The cooler (10) cools the hydrogen and water vapor mixture after the hydrogen production fuel-side product and hydrogen feedstock heat exchanger (9) releases waste heat. The gas-liquid separator (11) is used to perform gas-liquid separation on the cooled hydrogen and water vapor mixture. The separated liquid water is discharged as wastewater (K), and the purified hydrogen is fed into the hydrogen booster (12) to form reactive hydrogen (D).

8. The coupling system according to claim 1, characterized in that, The oil hydrotreating unit also includes a cooler (15), an oil-gas separator (16), and a circulating hydrogen compressor (17) connected in series downstream of the hydrotreating product and feedstock heat exchanger (13). The cooler (15) further cools the hydrotreating product after the initial heat exchange between the hydrotreating product and feedstock heat exchanger (13). The gas phase outlet of the oil-gas separator (16) is connected to the circulating hydrogen compressor (17) to perform gas-liquid separation on the cooled hydrotreating product. The output of the circulating hydrogen compressor (17) is divided into two paths: one path is connected back to the hydrotreating product and feedstock heat exchanger (13), and the other path is connected back to the hydrotreating reactor (14) to adjust the temperature of the hydrotreating reactor (14).

9. The coupling system according to claim 8, characterized in that, The output end of the circulating hydrogen compressor (17) is provided with a waste hydrogen (F) discharge branch. When the circulating hydrogen concentration is lower than the preset concentration, the circulating hydrogen purity is maintained by discharging waste hydrogen.

10. The coupling system according to claim 8, characterized in that, The oil hydrotreating unit also includes a fractionation tower (18), and the liquid phase outlet of the oil-gas separator (16) is connected to the fractionation tower (18) to output the hydrotreated oil product.

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