Direct air carbon capture and utilization system and method for realizing water-energy-carbon synergistic utilization based on dehydration before capture

Abstract

The invention provides a direct air carbon capture and utilization system and method for realizing water-energy-carbon synergistic utilization based on dehydration before capture. Comprising an air water taking unit, a direct air carbon capture module, an electrolyzed water unit, a green methanol preparation module, a renewable energy heat supply device and a renewable energy power generation device. The air water taking unit adsorbs moisture in wet air to obtain dry air, the dry air immediately enters the air carbon capture module directly, and capture of carbon dioxide is completed in a physical adsorption mode. And the captured carbon dioxide is used as a raw material and is mixed and reacted with hydrogen generated by the water electrolysis unit to generate green methanol, so that a green process cycle is formed. The influence of water on direct air carbon capture is effectively relieved, the economical efficiency of the system is improved, heat energy generated by the system is fully utilized, dependence on external energy is reduced, stable operation of the system is ensured, meanwhile, efficient utilization of the energy and effective control over the cost are achieved, and greenness and sustainability of the whole system are guaranteed.

Description

Technical Field

[0001] The present invention belongs to the intersection of energy and chemical industry, and involves direct air carbon capture, air water extraction, heat utilization and green methanol preparation. Specifically, it is a direct air carbon capture and utilization system and method based on pre-capture dehydration to achieve water-energy-carbon synergistic utilization. Background Art

[0002] As human activities lead to an increase in the concentration of greenhouse gases such as carbon dioxide in the atmosphere, the greenhouse effect has intensified, which has had a profound impact on the global climate. Direct air capture (DAC) is a promising technical solution to mitigate the rise in global average temperature and related consequences, mainly to cope with global climate change and achieve the goals of carbon reduction and carbon neutrality.

[0003] Water plays an indispensable role in every step of DAC. In the DAC process, water competes with carbon dioxide for adsorption sites, affecting the adsorption capacity and selectivity of the adsorbent for carbon dioxide and reducing the carbon capture efficiency. Additional energy is required to remove water during adsorbent regeneration, and water interferes with the energy recovery process, increasing the energy demand of the entire DAC process. A humid environment can damage the adsorbent structure, corrode metal parts, shorten the service life of the adsorbent, and increase operating costs, thereby reducing the economic feasibility of DAC technology.

[0004] To address the impact of water on the DAC process, designing a DAC system with water management is a feasible solution. Although there is potential energy loss in the water management process, the synergy of heat integration can greatly reduce the energy consumption and carbon footprint of the system. Summary of the invention

[0005] The purpose of the present invention is to couple an air water intake unit, a direct air carbon capture module, and a green methanol preparation module to construct a direct air carbon capture and utilization system based on pre-capture dehydration to achieve water-energy-carbon synergistic utilization, so as to remove moisture entering the direct air carbon capture module, realize effective utilization of system thermal energy, reduce energy demand, and improve the economy of the system.

[0006] To achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is as follows: a direct air carbon capture and utilization system based on the coordinated utilization of front-end dehydration and heat, including an air water intake unit, a direct air carbon capture module, a water electrolysis unit, a green methanol preparation module, a renewable energy heating device and a renewable energy power generation device.

[0007] The air water intake unit ensures that the humid air is more thoroughly dehydrated before entering the direct air carbon capture module. After the adsorption bed of the air water intake unit is saturated with adsorption, water vapor is released by heating and desorption.

[0008] The dehydration of the air water intake unit utilizes the adsorption enthalpy in the direct air carbon capture exothermic adsorption step and the waste heat generated in the green methanol preparation process to partially compensate for the energy required for the regeneration of the air water intake bed, promote the regeneration of the air water intake bed, realize the effective utilization and transfer of the internal energy of the system, improve the energy utilization efficiency and economy of the entire system, and reduce the additional demand for external energy.

[0009] The renewable energy heating device provides heat energy to the air water intake unit and the direct air carbon capture module respectively; the renewable energy power generation device provides electric energy to the direct air carbon capture module, the water electrolysis hydrogen production unit and the green methanol preparation module respectively.

[0010] Optionally, the renewable energy power generation device includes one or more of a wind power generation unit and a photovoltaic power generation unit.

[0011] Optionally, the heat source of the renewable energy heating device includes one or more of solar energy and geothermal energy.

[0012] The air from the air water intake unit enters the carbon capture module for adsorption treatment, and the adsorbed carbon dioxide is desorbed to obtain carbon dioxide; the water electrolysis unit generates hydrogen by electrolyzing water; the carbon dioxide and the hydrogen are mixed in the mixing compressor and enter the methanol reactor to prepare green methanol.

[0013] Furthermore, the waste heat generated by the green methanol preparation module is used for the air water extraction and desorption module; and the adsorption enthalpy generated by the direct air carbon capture device is used to compensate for the heat required by the air water extraction unit.

[0014] Furthermore, the water vapor released by the air water intake unit and the water released by the green methanol production module are used to produce hydrogen by electrolysis of water through a water replenishment device.

[0015] Furthermore, the adsorption process of the direct air carbon capture module is a physical adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X.

[0016] Furthermore, the adsorption process of the air water intake unit is a physical adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X.

[0017] Furthermore, the conditions of the air water intake unit include: relative humidity of 30% to 80%, and desorption temperature of 80 to 120°C.

[0018] Furthermore, the desorption process of the direct air carbon capture module is thermal desorption; the conditions of the thermal desorption include: the desorption temperature is 100-130°C, preferably 105-120°C.

[0019] Furthermore, the conditions for synthesizing methanol include: a temperature of 220 to 280° C., preferably 230 to 260° C., and a pressure of 1.5 to 5 MPa.

[0020] Furthermore, the molar ratio of H2 / CO2 is 3.

[0021] Air water extraction units effectively mitigate the effects of water on DAC by selectively extracting water from the air before it reaches the adsorbent bed. These dehydration methods are versatile and can be applied to a variety of DAC technologies. Dehydration is important for adsorbents because the performance of some adsorbents is negatively affected by competitive adsorption (e.g., zeolites) or structural degradation (e.g., metal organic frameworks) in humid environments.

[0022] During the adsorption of carbon dioxide by zeolite 13X, when the environment is humid, water vapor will compete with carbon dioxide for adsorption sites. Experiments have shown that within a certain temperature and pressure range, humidity will affect the adsorption of carbon dioxide on zeolite 13X. Due to the competitive relationship between the adsorption mechanisms of water molecules and carbon dioxide molecules on zeolite, the amount of carbon dioxide adsorbed by zeolite may be reduced in humid conditions.

[0023] A humid environment will affect the adsorption heat of carbon dioxide by zeolite 13X. The adsorption heat is an important parameter to measure the energy change of the adsorption process. When the environment is humid, the presence of water molecules will affect the interaction between carbon dioxide and zeolite, thereby changing the adsorption heat and further affecting the adsorption performance.

[0024] Compared with the existing technology, if air source heat pump is used as the heat integration method, the heat integration process of CO2 can save 55.6% of energy consumption.

[0025] Therefore, effective water management and heat integration are crucial for direct air carbon capture systems, and have far-reaching significance for improving the economic efficiency of the technology, reducing system energy consumption and promoting its large-scale industrial application.

[0026] The present invention focuses on the direct air carbon capture system, and realizes the water management function through coordinated heat integration. The selective adsorption characteristics of the adsorbent to water are used to remove the water entering the direct air carbon capture system, effectively alleviating the impact of water on the direct air carbon capture process, improving the economy of the system, making full use of the heat energy generated by the system, reducing dependence on external energy sources, ensuring the system to achieve efficient energy utilization and effective cost control while operating stably. At the same time, the electricity and heat energy used by the system during operation are provided by renewable energy, ensuring the greenness and sustainability of the entire system.

[0027] Effective water management and heat integration in direct air carbon capture systems reduce the energy consumption of the system and are of great significance in promoting the large-scale industrial application of direct air capture (DAC) and improving capture efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic flow chart of a direct air carbon capture and utilization system for realizing synergistic utilization of water, energy and carbon based on pre-capture dehydration according to the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific implementation methods.

[0030] See also Figure 1 As shown, the present invention discloses a direct air carbon capture and utilization system based on pre-capture dehydration to achieve water-energy-carbon synergistic utilization. An air water intake unit is used to ensure that moisture is more thoroughly removed before the air contacts the direct air carbon capture system, thereby achieving water management and heat integration of the direct air carbon capture system. Finally, green methanol is prepared by mixing and reacting the raw materials obtained from the direct air carbon capture system and the water electrolysis system.

[0031] In summary, a direct air carbon capture and utilization system based on pre-capture dehydration to achieve water-energy-carbon synergistic utilization includes an air water intake unit, a direct air carbon capture module, a water electrolysis unit, a green methanol preparation module, a renewable energy heating device and a renewable energy power generation device.

[0032] The air water intake unit includes an air water intake adsorption module and an air water intake desorption module; the air water intake unit has two working modes, represented by the air water intake adsorption module and the air water intake desorption module; before the air water intake unit reaches the saturation state, the adsorption bed working mode of the unit is the adsorption mode, which can realize the adsorption of moisture in the air; when the adsorption bed of the air water intake unit reaches the saturation state and no longer has the ability to adsorb moisture in the air, the working mode of the unit is the desorption mode, and energy needs to be provided at this time to realize the desorption of the adsorbed water molecules in the unit.

[0033] The direct air carbon capture module provides raw material carbon dioxide for the green methanol preparation module; the water electrolysis unit provides raw material hydrogen for the green methanol preparation module; the green methanol preparation module uses the raw materials provided by the direct air carbon capture module and the water electrolysis unit to prepare green methanol.

[0034] The renewable energy heating device provides heat energy to the desorption module and the direct air carbon capture module of the air water intake unit respectively; the renewable energy power generation device provides electric energy to the direct air carbon capture module, the water electrolysis hydrogen production device and the green methanol preparation module respectively.

[0035] The method of the present invention comprises the following steps: passing humid air into an air water intake adsorption module, and the air water intake adsorption module adsorbs water in the humid air. At this time, after the air water intake adsorption module reaches a saturated state, the air water intake desorption module is started, which is an air water intake desorption mode; and the water in the air water intake desorption module is released by heating.

[0036] The dry air from the air water intake unit enters the direct air carbon capture module for adsorption treatment, and the adsorbed carbon dioxide is desorbed to obtain carbon dioxide; the water electrolysis unit produces hydrogen through the water electrolysis hydrogen production module; the carbon dioxide and the hydrogen are mixed by the mixing compressor and enter the reactor in the green methanol preparation module to prepare green methanol.

[0037] The system of the present invention, supported by renewable energy, can provide heat and electricity for the air water extraction unit, the carbon capture unit and the green methanol preparation system unit, thereby reducing dependence on traditional energy sources; the system can utilize the carbon dioxide captured in the air and convert it into high value-added products, thereby improving the economic benefits of the overall process.

[0038] As a better embodiment of the present invention, the air water intake unit ensures that moisture is removed more thoroughly before contacting the CO2 adsorbent and generates a water product; the dehydration process of the air water intake unit utilizes the adsorption enthalpy in the exothermic adsorption step and the waste heat generated by the green methanol preparation process, which can partially compensate for the energy required for regeneration of the air water intake unit.

[0039] As a preferred embodiment of the present invention, in the air water intake unit, water can be removed from the feed by utilizing the waste heat generated by the green methanol preparation and the adsorption enthalpy in the exothermic adsorption step to promote the regeneration of the dehydration bed.

[0040] As a preferred embodiment of the present invention, the renewable energy power generation device includes one or more of a wind power generation unit and a photovoltaic power generation unit; the energy source of the renewable energy heating device includes one or more of solar energy and geothermal energy.

[0041] As a better embodiment of the present invention, the adsorption treatment of the direct air carbon capture module is a physical adsorption method, specifically a vacuum temperature swing adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X; the adsorption treatment of the air water intake unit is a physical adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X.

[0042] As a preferred embodiment of the present invention, the conditions of the air water intake unit include: relative humidity of 30% to 80%, and desorption temperature of 80 to 120°C.

[0043] As a preferred embodiment of the present invention, the desorption process of the direct air carbon capture module is thermal desorption; the conditions of the thermal desorption include: the desorption temperature is 100 to 130°C, preferably 105 to 120°C.

[0044] As a preferred embodiment of the present invention, the green methanol preparation process has a reaction temperature of 200-350°C, preferably 230-260°C, a pressure of 1.5-5MPa, and a molar ratio of H2 / CO2 of 3.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A direct air carbon capture and utilization system based on pre-capture dehydration to achieve water-energy-carbon synergistic utilization, characterized in that: It includes an air water intake unit, a direct air carbon capture module, a water electrolysis unit, a green methanol production module, a renewable energy heating device and a renewable energy power generation device; the renewable energy heating device provides heat energy to the desorption module and the direct air carbon capture module of the air water intake unit respectively; the renewable energy power generation device provides electric energy to the direct air carbon capture module, the water electrolysis hydrogen production module and the green methanol production module respectively; The air water intake unit comprises an air water intake adsorption module and an air water intake desorption module; the air water intake unit has two working modes, namely, an air water intake adsorption mode and an air water intake desorption mode; before the air water intake unit reaches a saturated state, the adsorption bed working mode of the unit is an adsorption mode, which realizes the adsorption of water in the air; when the adsorption bed of the air water intake unit reaches a saturated state and no longer has the ability to adsorb water in the air, the working mode of the unit is a desorption mode, and energy needs to be provided at this time to realize the desorption of adsorbed water molecules in the unit; The water electrolysis unit comprises a water replenishing device and a water electrolysis hydrogen production device connected to the outlet of the water replenishing device.

2. The system according to claim 1, characterized in that The water vapor generated by the air water extraction and desorption module and the water generated by the green methanol preparation module are used for the water replenishment device.

3. The system according to claim 1, characterized in that The renewable energy power generation device includes one or more of a wind power generation unit and a photovoltaic power generation unit.

4. The system according to claim 1, characterized in that The energy source of the renewable energy heating device includes one or more of solar energy and geothermal energy.

5. A method of using the system according to any one of claims 1, characterized in that: The method comprises: S1: Wet air is passed into the air water absorption module, and the air water absorption module absorbs water in the wet air. At this time, the air water absorption module acts as an air water desorption module after the water absorption reaches saturation; the water in the air water absorption module is released by heating; S2: The air from the air water intake unit enters the direct air carbon capture module for adsorption treatment, and the adsorbed carbon dioxide is desorbed to obtain carbon dioxide; S3: The water electrolysis unit generates hydrogen through the water electrolysis hydrogen production module; the carbon dioxide and the hydrogen are mixed in the mixing compressor and enter the methanol reactor to prepare green methanol; The heat used comes from the renewable energy heating device, the adsorption enthalpy released during the adsorption process of the direct air carbon capture module, and the waste heat generated by the green methanol production module; The adsorption treatment of the direct air carbon capture module is a physical adsorption method, specifically a vacuum temperature swing adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X; The air water intake unit adsorption treatment is a physical adsorption method, and the adsorbent used in the physical adsorption is zeolite 13-X; The conditions of the air water intake unit include: relative humidity of 30% to 80%, desorption temperature of 80 to 120°C; The desorption process of the direct air carbon capture module is thermal desorption; the conditions of the thermal desorption include: the desorption temperature is 100-130°C; The conditions for synthesizing methanol include: a temperature of 220-280° C. and a pressure of 1.5-5 MPa.

6. The method according to claim 5, characterized in that The desorption temperature is 105-120°C.

7. The method according to claim 5, characterized in that The temperature of the synthetic methanol is 230-260°C.

8. The method according to claim 5, characterized in that The molar ratio of H2 / CO2 is 3.

Images