Patent Application
20230228485
The present disclosure relates to the field of energy conversion and cold energy recovery, in particular to a photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device and a use method.
In recent years, the accelerated consumption of fossil fuels has led to more and more environmental problems, and the content of CO2 in the exhaust gas of various industrial uses is quite high. Controlling the emission of greenhouse gas CO2 has attracted worldwide attention. In addition to directly reducing the amount of CO2, more importantly, CO2 is further recycled from industrial tail gas, which not only can reduce environmental pollution and promote the development of low-carbon economy, but also can increase economic benefits for enterprises, which has very important environmental, social and economic significance. Dry ice, that is, solid carbon dioxide, is widely used in many fields, such as mold cleaning, petrochemical industry, printing industry, food refrigeration, fire fighting, medicine and health, etc., because of its easy volatilization, non-toxicity, tasteless performance, and no liquid formation or residue during phase change. At present, domestic and foreign CO2 industrial liquefaction usually pressurizes atmospheric CO2 gas to 1.6˜2.5 MPa by three-stage compression, which is cooled and liquefied by a refrigeration unit, and the liquefied CO2 is expanded by throttling to prepare dry ice. This process consumes a lot of energy for the compression of carbon dioxide and the refrigeration capacity of the refrigeration unit. Therefore, how to effectively reduce the system energy consumption is the main improvement direction and goal of dry ice preparation technology.
With the rapid development of economy in China, the demand for hydrogen in various industries, especially coal chemical industry, is increasing year by year. In the process of hydrogen production by electrolysis of water, no pollution gas is discharged, and the products are only hydrogen and oxygen, which is the preferred method for preparing hydrogen. Green solar power generation can provide energy source for hydrogen production by electrolysis of water, liquefy and store the surplus hydrogen produced when the photoelectric power is sufficient, and vaporize the stored liquid hydrogen when the photoelectric power is insufficient to supply the liquid hydrogen to the downstream process pipe network, thus meeting the demand of continuously using industrial hydrogen. At present, the process of hydrogen liquefaction is very mature. However, there is a great loss of cold energy in the process of energy releasing, vaporization and reuse of liquid hydrogen. Generally, a liquid hydrogen vaporizer uses a natural ventilation and air bathing manner, which fails to realize the optimized recovery of cold energy when vaporizing liquid hydrogen at a low temperature of about 20K, resulting in waste of cold energy and cold pollution. The cold energy utilization technology of liquid hydrogen at a low temperature of about 20K is combined with liquid CO2 and the dry ice preparation technology, which not only can significantly reduce the working pressure of liquid CO2 and a dry ice preparation system and the load of a refrigeration device, reduce the energy consumption and cost in the preparation process of liquid CO2 and dry ice, promote the recovery of CO2 from industrial tail gas and reduce carbon emissions, but also effectively improve the energy utilization rate of low-temperature liquid hydrogen, reduce the environmental cold pollution resulted from liquid hydrogen gasification using air in the traditional process, help to promote the healthy development of the low-temperature liquid hydrogen industry, and enjoy good environmental and social benefits.
The technical problem to be solved by the present disclosure is to provide a route of a photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production process, which is used for solving the problems of intermittence of photovoltaic power generation, low efficiency of industrial tail gas CO2 recycling, low energy utilization rate of low-temperature liquid hydrogen and high energy consumption of dry ice preparation.
In order to achieve the above purpose, the present disclosure uses the following technology: a photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device, which comprises a photoelectric conversion liquid hydrogen energy storage unit and a dry ice production unit with optimized recovery of liquid hydrogen cold energy, wherein the photoelectric conversion liquid hydrogen energy storage unit and the dry ice production unit with optimized recovery of liquid hydrogen cold energy share a hydrogen-carbon dioxide heat exchanger II, a hydrogen-nitrogen heat exchanger and a hydrogen-carbon dioxide heat exchanger I, wherein the photoelectric conversion liquid hydrogen energy storage unit is further provided with a hydrogen liquefaction unit, an air separation device and a liquid nitrogen storage tank, the liquid nitrogen storage tank is connected with the hydrogen liquefaction unit, the hydrogen liquefaction unit is connected with a low-temperature liquid hydrogen storage tank through a liquid hydrogen pipeline, hydrogen prepared by photovoltaic power generation is refrigerated and liquefied by self-expansion after exchanging heat with liquid nitrogen from the liquid nitrogen storage tank in the mature hydrogen liquefaction unit, and is sent to the low-temperature liquid hydrogen storage tank through the liquid hydrogen pipeline for storage, the process of photoelectric conversion of liquid hydrogen is completed, the low-temperature liquid hydrogen storage tank is connected to the hydrogen-nitrogen heat exchanger, the hydrogen-carbon dioxide heat exchanger I and the hydrogen-carbon dioxide heat exchanger II in sequence, a low-temperature liquid hydrogen pump is provided between the low-temperature liquid hydrogen storage tank and the hydrogen-nitrogen heat exchanger, the air separation device is connected to the hydrogen-carbon dioxide heat exchanger I and the hydrogen-nitrogen heat exchanger through a nitrogen pipeline in sequence, and finally the product liquid nitrogen is stored in the liquid nitrogen storage tank for recycling.
Preferably, the dry ice production unit with optimized recovery of liquid hydrogen cold energy is further provided with a CO2 storage tank, a dry ice machine and a liquid CO2 storage tank, wherein the CO2 storage tank and the dry ice machine are connected with the hydrogen-carbon dioxide heat exchanger II and the hydrogen-carbon dioxide heat exchanger I through a tee pipeline in sequence, one end of the hydrogen-carbon dioxide heat exchanger I is connected to the liquid CO2 storage tank, and the other end thereof is connected to the dry ice machine through a pipeline to form a loop.
Preferably, the hydrogen-nitrogen heat exchanger, the hydrogen-carbon dioxide heat exchanger I and the hydrogen-carbon dioxide heat exchanger II has one of a shell-and-tube structure, a plate-fin structure and a coiled-tube structure or a combination thereof.
Preferably, the low-temperature liquid hydrogen storage tank, the liquid nitrogen storage tank and the low-temperature liquid CO2 storage tank use a Dewar tank or a low-temperature storage tank.
Preferably, the low-temperature liquid hydrogen pump has a piston or centrifugal structure.
A use method of the photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device is provided, wherein the method comprises the following steps:
The present disclosure has the following beneficial effects. Intermittent photoelectric energy is stored in the form of liquid hydrogen, so as to effectively solve the problem that it is difficult to supply hydrogen continuously for industry due to photoelectric fluctuation. The process of optimized recovery of cold energy uses the high-grade and low-grade cold energy during liquid hydrogen vaporization to prepare liquid nitrogen and dry ice, respectively, which effectively reduces the device investment and the operation cost. In the process route of the present disclosure, the cold energy utilization technology of liquid hydrogen at a low temperature of about 20K is combined with the liquid CO2 and dry ice preparation technology, which can significantly reduce the energy consumption and cost in the preparation process of liquid CO2 and dry ice, promote the recovery of CO2 from industrial tail gas and reduce carbon emissions, and at the same time, which can effectively improve the energy utilization rate of low-temperature liquid hydrogen, reduce the environmental cold pollution resulted from the traditional process, and promote the healthy development of the low-temperature liquid hydrogen industry.
The present disclosure will be described in detail with reference to the attached drawings hereinafter. As shown in
A use method of the photoelectric hydrogen production energy storage and cold energy recovery coupled dry ice production device is provided, wherein the method comprises the following steps:
Specific embodiments:
For example, nitrogen of about 0.15 MPa at 25° C. exchanges heat with low-temperature hydrogen in the hydrogen-carbon dioxide heat exchanger I11. The pre-cooled nitrogen further exchanges heat with liquid hydrogen from the low-temperature liquid hydrogen storage tank 5 pressurized to about 5.5 MPa by the low-temperature liquid hydrogen pump 6 in the hydrogen-nitrogen heat exchanger 7, fully recovers high-grade cold energy of liquid hydrogen of about 20K, and then is liquefied and stored in the low-temperature liquid nitrogen storage tank 8. Normal-temperature and normal-pressure CO2 from a CO2 storage tank is mixed with the low-temperature CO2 gas of about 0.11 MPa in the dry ice machine. The mixed CO2 is compressed to about 0.6 MPa by the CO2 compressor 16, and then is sent to the hydrogen-carbon dioxide heat exchanger II13 for heat exchange with low-temperature hydrogen of about 5.5 MPa from the hydrogen-carbon dioxide heat exchanger I11 for pre-cooling. The pre-cooled CO2 is then sent to the hydrogen-carbon dioxide heat exchanger I11 for further heat exchange with low-temperature hydrogen from the hydrogen-nitrogen heat exchanger 7, and then is liquefied and sent to the liquid CO2 storage tank 14 for storage. The pressurized liquid CO2 is sent to the dry ice machine 16 for throttling and expansion to prepare dry ice, in which part of the liquid CO2 absorbs heat and vaporizes into low-temperature CO2 gas to enter the circulation loop, and the other part of the liquid CO2 solidifies into dry ice and is sent to the dry ice storage tank for dry ice users. In this process route, liquid hydrogen of about 20K is sent to a downstream process pipe network after being reheated by the hydrogen-nitrogen heat exchanger 7, the hydrogen-carbon dioxide heat exchanger I11 and the hydrogen-carbon dioxide heat exchanger II13.
In the present disclosure, when photovoltaic power generation is insufficient, liquid hydrogen is vaporized and supplied to the downstream process through the dry ice production unit with optimized recovery of liquid hydrogen cold energy. In the process of vaporization of liquid hydrogen at a low-temperature of about 20K, the recovery of high-grade and low-grade cold energy is optimized to prepare liquid nitrogen from nitrogen and prepare dry ice from industrial tail gas purified CO2 at low cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210046797.3 | Jan 2022 | CN | national |
