Alcohol / ammonia synthesis device and reactor adapting to large fluctuation of renewable energy sources
By using multiple reactors of different sizes and multi-stream heat exchange reactors in the alcohol/ammonia synthesis process, combined with valve adjustment, the problem of frequent start-up and shutdown of the device caused by fluctuations in renewable energy was solved, and efficient and stable energy utilization and safe operation of the device were achieved.
Patent Information
- Application Number
- CN202422529739.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-09-19
- Estimated Expiration
- 2034-10-18
AI Technical Summary
During the power generation process of renewable energy, the energy input and power output fluctuate greatly, are intermittent and uncontrollable, resulting in frequent start-up and shutdown of the synthesis device, reducing energy utilization efficiency and shortening the life of the device and catalyst.
By using multiple reactors of different sizes, combined with multi-stream heat exchange reactors and valve adjustment under different load conditions, the alcohol/ammonia synthesis process can be stably operated within an operating flexibility of 10% to 120%, including flexible switching and thermal management of large and small reactors.
It improves energy utilization, avoids the abandonment of renewable energy, extends the service life of the device and catalyst, and reduces engineering difficulty and cost.
Smart Images
Figure CN223351643U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to chemical synthesis and consumption of renewable energy, in particular to an alcohol / ammonia synthesis device and a reactor with large fluctuations in renewable energy. Technical Background
[0002] Energy supply and demand imbalances and environmental pollution have become global challenges. The traditional fossil-fuel-based energy system is struggling to maintain its viability. Vigorously developing renewable energy and rebuilding a clean energy system dominated by renewable energy are key to resolving this challenge. Driven by the dual carbon goals, my country is actively promoting the deployment of renewable energy equipment. However, renewable energy is subject to environmental factors, and its energy input and power output cannot be precisely controlled like thermal power generation. Its high volatility, intermittent nature, randomness, and uncontrollable nature make it difficult to directly integrate into the power grid, leading to the widespread abandonment of renewable energy equipment.
[0003] Carbon dioxide hydrogenation to methanol and ammonia synthesis, as a means of consuming renewable energy locally, can effectively improve energy utilization and avoid the abandonment of renewable energy equipment. Numerous renewable energy-based alcohol / ammonia projects are currently being planned in China, including renewable energy gasification, carbon dioxide hydrogenation to methanol, or ammonia synthesis using nitrogen from air and hydrogen, along with subsequent refining processes. Methanol / ammonia synthesis, as a typical chemical plant, generally has an operating flexibility of 50% to 120%, making it difficult to operate outside this range. Because renewable energy fluctuates frequently and over a wide range, if peak shaving is not implemented, it will be abandoned when power generation is low, reducing energy efficiency and requiring the synthesis plant to be shut down. Frequent plant operation and shutdown significantly shortens the lifespan of the plant and catalysts, impacting safe operation.
[0004] To address this issue, some research has been conducted domestically. Generally speaking, these approaches involve storing a portion of electricity during peak power generation through mechanical or chemical energy storage methods, with the remainder supplied to the methanol / ammonia synthesis unit. During periods of low power generation, the stored energy is used to generate electricity to supplement renewable energy supply to the methanol / ammonia synthesis unit. These methods can, to a certain extent, avoid the energy waste associated with disabling renewable energy generation, while also enabling continuous operation of the synthesis unit, avoiding frequent shutdowns and starts. However, they are costly and require significant engineering challenges. Utility Model Content
[0005] The purpose of the utility model is to provide an alcohol / ammonia synthesis process with large fluctuations in renewable energy. By improving the alcohol / ammonia synthesis process route, an operational flexibility of 10% to 120% is achieved, and the synthesis device can continue to operate stably during peak or trough power supply from renewable energy.
[0006] An alcohol / ammonia synthesis process adaptable to large fluctuations in renewable energy sources includes synthesis and product separation, wherein fresh gas is mixed with recycled gas to form synthesis gas. The fresh gas used for methanol synthesis refers to a gas obtained by mixing hydrogen produced from renewable energy and CO2 in a certain proportion. The fresh gas used for ammonia synthesis refers to a gas obtained by mixing hydrogen produced from renewable energy and N2 extracted from the air in a certain proportion. The alcohol / ammonia synthesis process is provided with multiple reactors of different sizes, wherein the large reactor is filled with 60-90% of the catalyst amount and the small reactor is filled with 10-40% of the catalyst amount. When multiple large reactors are used, the catalyst loading of each large reactor is greater than or equal to the catalyst loading of each small reactor.
[0007] As a preference, the multiple reactors are two reactors of different sizes, the large reactor is filled with 80% of the catalyst, and the small reactor is filled with 20% of the catalyst.
[0008] The alcohol / ammonia synthesis process is adjusted as follows when the system load is different:
[0009] When the alcohol / ammonia synthesis process is operated at a low load of 10% to 25%, the synthesis gas only passes through the catalyst bed of the small reactor, and the outlet gas of the small reactor enters the large reactor to provide heat to maintain the temperature of the catalyst bed. When the load is increased in the future, the large reactor does not need to go through a temperature increase process and can be started immediately.
[0010] When the alcohol / ammonia synthesis process is operated at a low load of 25% to 50%, the large reactor is activated, and the synthesis gas is preheated and enters the large reactor and the small reactor respectively. Alternatively, the synthesis gas can be separated into another non-preheated mixed gas according to demand and mixed with the preheated mixed gas entering the small reactor. The outlet gas of the small reactor is mixed with the inlet gas of the large reactor and then enters the large reactor, thereby achieving thermal balance of the large reactor and preventing it from losing temperature and inactivation due to insufficient reaction heat.
[0011] When the alcohol / ammonia synthesis process is operated at a load of 50% to 120%, the large reactor and the small reactor are connected in parallel, and the synthesis gas enters the large reactor and the small reactor respectively after being preheated. The synthesis gas can also be separated into another non-preheated mixed gas according to demand and mixed with the preheated mixed gas entering the small reactor. The outlet gas of the small reactor is mixed with the outlet gas of the large reactor and then used to heat the synthesis gas.
[0012] As a preference, the large reactor is a multi-stream heat exchange reactor, and the heat exchange medium can be boiler water, gas, heat transfer oil or molten salt.
[0013] As a preference, the small reactor can be an air-cooled reactor or an adiabatic reactor.
[0014] An alcohol / ammonia synthesis device adaptable to large fluctuations in renewable energy comprises a compressor, a circulation machine, a heat exchanger, a cooler, a multi-stream heat exchange reactor, a small reactor and a separator. The compressor outlet is connected to the circulation machine outlet and the heat exchanger. The shell-side outlet of the heat exchanger is divided into two paths, respectively connected to the multi-stream heat exchange reactor and the small reactor. The outlet of the small reactor is connected to the reaction gas outlet pipeline, the reaction gas inlet pipeline and the heat exchange medium inlet pipeline of the multi-stream heat exchange reactor through pipelines with control valves, and then connected to the tube-side inlet of the heat exchanger. The tube-side outlet of the heat exchanger is sequentially connected to the cooler and the separator. The reaction gas inlet pipeline, the reaction gas outlet pipeline, the heat exchange medium inlet pipeline and the heat exchange medium outlet pipeline of the multi-stream heat exchanger are all provided with control valves. A bypass with a control valve is provided before the heat exchanger inlet, connected to the inlet of the small reactor.
[0015] When the above device is in operation, the control valves on each pipeline are opened or closed according to different load processes, so that the device can operate as follows:
[0016] 10% to 25% low-load process: the fresh gas pressurized by the compressor is mixed with the circulating gas compressed by the circulating machine, and then heat exchanged with the outlet gas of the multi-stream heat exchange reactor in the heat exchanger, and then enters the small reactor. The outlet gas of the small reactor enters at least one group of heat exchange tube bundles of the multi-stream heat exchange reactor to provide heat to the catalyst layer of the multi-stream heat exchange reactor to maintain the temperature of its catalyst. The outlet gas of the multi-stream heat exchange reactor is cooled by heat exchange in the heat exchanger and the cooler, and then enters the separator to separate the crude product. The separated gas is divided into two streams, one of which is used as circulating gas to be compressed by the circulating machine, and the rest is used as relaxation gas.
[0017] 25% to 50% low-load process: the fresh gas pressurized by the compressor is mixed with the circulating gas compressed by the circulating machine to form synthesis gas. The synthesis gas is heat exchanged with the outlet gas of the multi-stream heat exchange reactor in the heat exchanger and then enters the multi-stream heat exchange reactor and the small reactor respectively. The synthesis gas can also be separated into another mixed gas without preheating according to demand and mixed with the preheated mixed gas entering the small reactor. The outlet gas of the small reactor is mixed with the inlet gas of another heated multi-stream heat exchange reactor and then enters the multi-stream heat exchange reactor. The outlet gas of the multi-stream heat exchange reactor is cooled by heat exchange in the heat exchanger and the cooler, and then enters the separator to separate the crude product. The separated gas is divided into two streams, one of which is used as the circulating gas to be compressed by the circulating machine, and the rest is used as the relaxation gas.
[0018] 50% to 120% load process: The fresh gas pressurized by the compressor is mixed with the circulating gas compressed by the circulating machine to form synthesis gas, and then heat exchanged with the outlet gas of the multi-stream heat exchange reactor in the heat exchanger and entered the multi-stream heat exchange reactor and the small reactor respectively. The synthesis gas can also be separated into another mixed gas without preheating according to demand and mixed with the preheated mixed gas entering the small reactor. The outlet gas of the multi-stream heat exchange reactor and the outlet gas of the small reactor are mixed and cooled by heat exchange in the heat exchanger and the cooler, and then enter the separator to separate the crude product. The separated gas is divided into two streams, one of which is used as circulating gas to be compressed by the circulating machine, and the rest is used as relaxation gas.
[0019] As a preference, the heat exchange medium of the multi-stream heat exchange reactor can be boiler water, gas, heat transfer oil or molten salt.
[0020] As a preference, the small reactor is an air-cooled reactor or an adiabatic reactor.
[0021] A multi-stream heat exchange reactor for the alcohol / ammonia synthesis process adapted to large fluctuations in renewable energy, wherein the heat exchange tubes in the alcohol / ammonia synthesis reactor are divided into at least two heat exchange tube bundles, each heat exchange tube bundle carrying a different heat exchange medium, and the heat exchange tube spacing of the heat exchange tube bundles is 6 to 10 times the diameter of the catalyst loaded between the tubes.
[0022] As a preference, the distance between the heat exchange tubes of the heat exchange tube bundle is 6 to 8 times the diameter of the catalyst loaded between the tubes.
[0023] The process of this utility model is simple and easy to implement. While improving the safety and stability of the production equipment, it can significantly improve energy utilization and avoid the abandonment of wind and solar power. It has the following innovations and advantages:
[0024] 1. Installing multiple reactors of varying sizes, with large reactors filled with 60-90% of the catalyst volume and small reactors filled with 10-40% of the catalyst volume, can adapt to production load fluctuations caused by fluctuations in renewable energy supply and improve energy utilization during periods of low renewable energy supply. Each reactor can operate within a safe production load range, avoiding frequent startups and shutdowns. Furthermore, there is no need to install peak-shaving devices to smooth out fluctuations, reducing investment and engineering implementation difficulty.
[0025] 2. According to the different load conditions of the system, the opening and operating modes of multiple reactors are adjusted. The process flow can be quickly switched by simply adjusting the valves to meet different production loads. The control is simple and the response is fast to cope with the rapid fluctuations of renewable energy. For example, when the load is low at 10% to 25%, only the small reactor is turned on, and the gas from the small reactor outlet is used to enter the large reactor for insulation. When the load is added in the future, the large reactor does not need to go through the heating process and can be started immediately; when the load is low at 25% to 50%, the large and small reactors are activated at the same time to achieve thermal balance of the large reactor and avoid its deactivation due to low reaction heat; when the load is 50% to 120%, the large reactor and the small reactor are connected in parallel, and each reactor operates independently, which is easy to operate and control.
[0026] 3. The large reactor adopts a multi-stream heat exchange reactor. During operation, a variety of heat exchange media can be selected for efficient heat exchange and effective control of the catalyst bed temperature. When it is stopped, the outlet gas and heat exchange medium of the small reactor can be used to keep the reactor warm and maintain a hot standby state. It can be started immediately when the load is added. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a simplified flow chart of the device of the utility model.
[0028] Figure 2 The utility model is a flow chart of the process under 10-25% load when the process is used for synthesizing green alcohol with disorderly and large fluctuations in wind and photovoltaic power.
[0029] Figure 3 The utility model is a flow chart of the process under 25-50% load when the process is used for synthesizing green alcohol with disorderly and large fluctuations in wind and solar power.
[0030] Figure 4 The utility model is a flow chart of the process under 50-120% load when the process is used for synthesizing green alcohol with disorderly and large fluctuations in wind and photovoltaic power.
[0031] Description of reference numerals:
[0032] C1-Compressor C2-Circulator R1-Multi-stream heat exchange reactor R2-Small reactor
[0033] E1-heat exchanger E2-cooler S1-separator S2-steam drum
[0034] V1-first valve V2-second valve V3-third valve V4-fourth valve
[0035] V5-fifth valve V6-sixth valve V7-seventh valve DETAILED DESCRIPTION
[0036] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. However, the protection scope of the present invention is not limited to the following embodiment.
[0037] Example 1
[0038] like Figure 1 As shown, the alcohol / ammonia synthesis device of the present invention that adapts to large fluctuations in renewable energy includes a compressor C1, a circulation machine C2, a heat exchanger E1, a cooler E2, a multi-stream heat exchange reactor R1, a small reactor R2 and a separator S1. The outlet of the compressor C1 is connected to the outlet of the circulation machine C2 and the inlet of the heat exchanger E1. The shell-side outlet pipeline of the heat exchanger E1 is divided into two paths, one of which is provided with a first valve V1 and connected to the multi-stream heat exchange reactor R1, and the other is connected to the small reactor R2. The outlet of the small reactor R2 is divided into two paths, one of which is provided with a second valve V2 and is divided into two paths, and one of which is provided with a sixth valve V6 and connected to the multi-stream heat exchange reactor E1. The reaction gas inlet pipeline of the multi-stream heat exchange reactor E1 is connected to the other branch of the outlet pipeline of the small reactor R2, and the third valve V3 is connected to the reaction gas outlet pipeline and the heat exchange medium outlet pipeline of the multi-stream heat exchange reactor, and then connected to the tube-side inlet of the heat exchanger E1. The tube-side outlet of the heat exchanger E1 is connected to the cooler E2 and the separator S1 in sequence. The heat exchange medium outlet pipeline of the multi-stream heat exchange reactor is provided with a seventh valve V7. The shell-side inlet of the heat exchanger E1 is provided with a bypass of the fourth valve V4 connected to the inlet pipeline of the small reactor R2. The gas outlet of the separator S1 is divided into two routes, one of which is connected to the circulation machine C2 and the other is the relaxation gas.
[0039] The above-mentioned device is used in the green alcohol synthesis process. The multi-stream heat exchange reactor adopts a spirally wound tube structure. The catalyst in the reactor is installed between the tubes. The heat exchange tubes in the multi-stream heat exchange reactor R1 are divided into two groups of heat exchange tube bundles, one for steam and the other for reaction gas. The heat exchange tube spacing of the heat exchange tube bundles is 8 times the diameter of the catalyst loaded between the tubes. The multi-stream heat exchange reactor R1 is connected to the steam drum S2. To adapt to the disorderly and large fluctuations in wind and solar power, the valves of each pipeline are opened or closed at different system load states to ensure that the system operates according to the following requirements:
[0040] 10% to 25% low load process: open the second valve V2, the fifth valve V5, and the seventh valve V7, and close the first valve V1, the third valve V3, the fourth valve V4, and the sixth valve V6. The operation process of the device under this load state is as follows: Figure 2As shown, the fresh gas pressurized by the compressor C1 is mixed with the circulating gas compressed by the circulating machine C2, and then heat exchanged with the outlet gas of the multi-stream heat exchange reactor E1 to 170°C in the heat exchanger E1, and then enters the small reactor E2. The outlet gas of the small reactor E2 enters a part of the heat exchange tubes of the multi-stream heat exchange reactor E1 to keep the idle multi-stream heat exchange reactor E1 warm. The outlet gas of the multi-stream heat exchange reactor E1 is cooled to 40°C through heat exchange in the heat exchanger E1 and the water cooler E2, and then enters the separator S1 to separate the crude methanol. The separated gas is divided into two streams, one of which is used as the circulating gas to be compressed by the circulating machine C2, and the rest is used as the relaxation gas.
[0041] 25% to 50% low load process: open the first valve V1, the second valve V2, the fourth valve V4, and the sixth valve V6, and close the third valve V3, the fifth valve V5, and the seventh valve V7. The operation process of the device under this load state is as follows: Figure 3 As shown in the figure, the fresh gas compressed by the compressor C1 is mixed with the circulating gas compressed by the circulating machine C2 and then divided into
[0042] Two streams, one of which is heat exchanged with the outlet gas of the multi-stream heat exchange reactor R1 to 210℃ in the heat exchanger E1 and then divided into two streams, one of which is mixed with the other mixed gas that has not been heat exchanged, and the temperature after mixing is 170℃, and then enters the small reactor R2, the outlet gas of the small reactor R2 is mixed with the other heated inlet gas and then enters the multi-stream heat exchange reactor R1, the outlet gas of the multi-stream heat exchange reactor R1 is cooled to 40℃ through heat exchange in the heat exchanger E1 and the cooler E2, and then enters the separator S1 to separate the crude methanol. The separated gas is divided into two streams, one of which is used as circulating gas to be compressed by the circulating machine C2, and the rest is used as relaxation gas.
[0043] 50% to 120% load process: open the first valve V1, the third valve V3, and the fourth valve V4, and close the second valve V2, the fifth valve V5, the sixth valve V6, and the seventh valve V7. The operation process of the device under this load state is as follows: Figure 4 As shown, the fresh gas pressurized by the compressor C1 is mixed with the circulating gas compressed by the circulating machine C2 and then divided into two streams, one of which is heat exchanged with the outlet gas of the multi-stream heat exchange reactor R1 to 210°C in the heat exchanger E1 and then divided into two streams, one of which directly enters the multi-stream heat exchange reactor R1, and the rest is mixed with the other mixed gas that has not been heat exchanged. The temperature after mixing is 170°C, and then enters the small reactor R2. The outlet gases of the multi-stream heat exchange reactor R1 and the small reactor R2 are mixed and then heat exchanged and cooled to 40°C by the heat exchanger E1 and the cooler E2, and then enter the separator S1 to separate the crude methanol. The separated gas is divided into two streams, one of which is used as the circulating gas to be compressed by the circulating machine C2, and the rest is used as the relaxation gas.
Claims
1. An alcohol / ammonia synthesis device that can adapt to large fluctuations in renewable energy, comprising a compressor, a circulator, a heat exchanger, a cooler, a multi-stream heat exchange reactor, a small reactor, and a separator, characterized in that: The compressor outlet is connected to the circulation machine outlet and the heat exchanger. The shell-side outlet of the heat exchanger is divided into two routes and respectively connected to the multi-stream heat exchange reactor and the small reactor. The outlet of the small reactor is respectively connected to the reaction gas outlet pipeline, reaction gas inlet pipeline and heat exchange medium inlet pipeline of the multi-stream heat exchange reactor through pipelines with control valves, and then connected to the tube-side inlet of the heat exchanger. The tube-side outlet of the heat exchanger is connected to the cooler and separator in sequence. The shell-side inlet pipeline, shell-side outlet pipeline, tube-side inlet pipeline and tube-side outlet pipeline of the multi-stream heat exchange reactor are all provided with control valves. A bypass with a control valve is provided in front of the heat exchanger inlet to connect to the inlet of the small reactor.
2. The alcohol / ammonia synthesis device capable of adapting to large fluctuations in renewable energy as claimed in claim 1, characterized in that: The heat exchange medium of the multi-stream heat exchange reactor can be boiler water, gas, heat transfer oil or molten salt.
3. The alcohol / ammonia synthesis device capable of adapting to large fluctuations in renewable energy as claimed in claim 1, characterized in that: The small reactor is an air-cooled reactor or an adiabatic reactor.
4. A multi-stream heat exchange reactor for the alcohol / ammonia synthesis device adapted to large fluctuations in renewable energy as claimed in claim 1, characterized in that: The heat exchange tubes in the multi-stream heat exchange reactor are divided into at least two groups of heat exchange tube bundles, each group of heat exchange tube bundles carries different heat exchange media, and the heat exchange tube spacing of the heat exchange tube bundles is 6 to 10 times the diameter of the catalyst loaded between the tubes.
5. The multi-stream heat exchange reactor according to claim 4, characterized in that: The distance between the heat exchange tubes of the heat exchange tube bundle is 6 to 8 times the diameter of the catalyst loaded between the tubes.