A direct contact gas-heat co-storage device and energy storage system

Abstract

The present invention provides a direct contact gas-heat co-storage device and an energy storage system, wherein the direct contact gas-heat co-storage device comprises a gas storage tank shell, wherein a molded CO2 adsorbent is arranged inside the gas storage tank shell, wherein a hole is arranged in the molded CO2 adsorbent, wherein both ends of the hole are connected to a heat exchange pipe, wherein a fluid is suitable for heat exchange with the molded CO2 adsorbent through the heat exchange pipe and the hole, and wherein an air inlet valve and an air outlet valve are arranged on both sides of the gas storage tank shell. The direct contact gas-heat co-storage device provided by the present invention can efficiently exchange heat with the molded CO2 adsorbent, and utilize the heat change during the adsorption and desorption of CO2 by the molded CO2 adsorbent to store heat, thereby improving the gas storage performance and economy of the gas-heat co-storage device.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a direct contact gas-heat co-storage device and an energy storage system. Background Art

[0002] In the process of CO2 energy storage, a closed cycle is required to prevent CO2 gas leakage and store CO2 gas. In the prior art, in order to improve the storage capacity of CO2 gas, the gas storage density is often increased by increasing the gas storage pressure, but this method will increase the wall thickness of the gas storage device, thereby increasing the investment cost, and the high-pressure gas storage method has a greater safety hazard.

[0003] Silicon-aluminum-based and carbon-based materials with rich microporous structures can adsorb a large amount of CO2 molecules and can be used as an effective means of high-density gas storage under low-pressure conditions. However, the equilibrium adsorption capacity of the adsorbent is greatly affected by temperature, and the thermal effect during adsorption and desorption will have a great impact on the adsorption performance of the adsorbent. In the prior art, the commonly used adsorbent is a porous medium adsorbent. Due to its high porosity and poor thermal conductivity, it leads to low heat exchange efficiency. Therefore, it is urgent to solve the problem of efficient heat exchange of the adsorbent during the adsorption and desorption process, so as to control the temperature and improve the gas storage performance and economy. Summary of the invention

[0004] The problem solved by the present invention is how to achieve efficient heat exchange during CO2 gas adsorption and desorption, thereby improving gas storage performance and economy.

[0005] In order to solve the above problems, the present invention provides a direct contact gas-heat co-storage device, including a gas tank shell, a molded CO2 adsorbent is arranged inside the gas tank shell, and a channel is arranged in the molded CO2 adsorbent. Both ends of the channel are connected to the heat exchange pipe, and the fluid is suitable for heat exchange with the molded CO2 adsorbent through the heat exchange pipe and the channel. An air inlet valve and an air outlet valve are respectively arranged on both sides of the gas tank shell.

[0006] Preferably, the air inlet valve and the air outlet valve are pressure controlled valves.

[0007] Preferably, the direct contact gas-heat co-storage device further comprises a heat storage tank and a cold storage tank, and the heat storage tank and the cold storage tank are suitable for exchanging heat with the fluid in the heat exchange pipeline.

[0008] Preferably, the heat exchange medium in the heat storage tank and the cold storage tank is molten salt.

[0009] The present invention combines the CO2 adsorption and desorption process with heat storage by utilizing the heat changes in the process of adsorption and desorption of CO2 by the molded CO2 adsorbent, as well as the influence of temperature changes on the CO2 adsorption capacity of the molded CO2 adsorbent. When exhausting, high-temperature fluid is input to reduce the adsorption capacity of the molded CO2 adsorbent, and the outlet valve is opened for exhaust. At the same time, the CO2 molded adsorbent stores the desorption heat and the sensible heat of the adsorbent; and when inflating, low-temperature fluid is input to increase the adsorption capacity of the molded CO2 adsorbent, and the inlet valve is opened for inflation. The invention can store heat by utilizing the heat changes while completing the CO2 inflation and exhaust, thereby realizing gas heat. Co-storage; in addition, by setting a channel in the molded CO2 adsorbent, and connecting both ends of the channel to the heat exchange pipe, the fluid used for heat exchange flows through the channel and directly contacts with the molded CO2 adsorbent, thereby improving the heat exchange efficiency between the fluid and the molded CO2 adsorbent, and improving the temperature uniformity of the molded CO2 adsorbent, thereby avoiding the problem of low heat exchange efficiency caused by poor thermal conductivity of the porous medium adsorbent, so as to ensure its gas storage performance; the direct contact gas-heat co-storage device provided by the present invention can efficiently exchange heat with the molded CO2 adsorbent, and utilize the heat change in the process of adsorption and desorption of CO2 by the molded CO2 adsorbent to store heat, thereby improving the gas storage performance and economy of the gas-heat co-storage device.

[0010] Another object of the present invention is to provide an energy storage system, comprising the above-mentioned direct contact gas-heat co-storage device and a heat network.

[0011] Preferably, a heat exchanger is also included, and the heat storage tank or the cold storage tank exchanges heat with the fluid in the heat exchange pipeline through the heat exchanger.

[0012] Preferably, a heat pump is further included, and the heat network return water in the heat network is suitable for being converted into a low-temperature fluid or a high-temperature fluid through the heat pump.

[0013] Preferably, the heat of the direct contact gas-heat co-storage device is changed by the low-temperature fluid or high-temperature fluid in the heat network, thereby performing inflation and exhaust.

[0014] Preferably, when exhaust is required, the high-temperature fluid in the heat network is input into the direct contact gas-heat storage device for heat exchange, so that the CO2 gas in the molded CO2 adsorbent is desorbed and discharged, and at the same time the CO2 molded adsorbent stores the desorption heat and the sensible heat of the adsorbent.

[0015] Preferably, when inflation is required, the low-temperature fluid in the heat network is input into the direct contact gas-heat storage device for heat exchange, and CO2 gas is input at the same time, so that the molded CO2 adsorbent adsorbs the input CO2 gas. The adsorption heat and sensible heat of the adsorbent generated in this process are carried out by the low-temperature fluid and then supplied through the heat network.

[0016] The present invention combines a direct contact gas-heat storage device with a heat network to form an energy storage device, and can reasonably utilize the cold and hot circulation device in the heat network to exchange heat with the CO2 adsorbent in the gas-heat storage device, thereby ensuring the gas storage performance while improving the energy storage capacity. At the same time, it can also utilize the heat change of the CO2 adsorbent in the process of adsorbing and desorbing CO2 to store heat, which has high economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a direct contact gas-heat co-storage device in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of the pores in the molded CO2 adsorbent in an embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of the working process of the direct contact gas-heat co-storage device in the exhaust heat storage process in an embodiment of the present invention;

[0020] Figure 4 It is a schematic diagram of the working process of the direct contact gas-heat co-storage device in the gas charging heat storage process in an embodiment of the present invention.

[0021] Description of reference numerals:

[0022] 1-gas storage tank shell; 11-molded CO2 adsorbent; 111-channel; 12-heat exchange pipeline; 13-inlet valve; 14-outlet valve; 2-heat storage tank; 3-cold storage tank; 4-heat exchanger; 5-heat pump. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0024] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention can be combined with each other. In addition, the direction indicated by the arrow in the accompanying drawings is the flow direction of the gas or medium.

[0025] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a direct contact gas-heat co-storage device, including a gas storage tank shell 1, a molded CO2 adsorbent 11 is arranged inside the gas storage tank shell 1, a channel 111 is arranged in the molded CO2 adsorbent 11, both ends of the channel 111 are connected to the heat exchange pipe 12, the fluid is suitable for heat exchange with the molded CO2 adsorbent 11 through the heat exchange pipe 12 and the channel 111, and an air inlet valve 13 and an air outlet valve 14 are respectively arranged on both sides of the gas storage tank shell 1.

[0026] Specifically, the gas tank shell 1 is made of steel and has been subjected to heat preservation treatment to improve the heat preservation performance of the gas tank shell 1 and reduce heat loss. A molded CO2 adsorbent 11 is provided in the gas tank shell 1. The molded CO2 adsorbent 11 can adsorb and desorb CO2 gas, and the higher the temperature, the worse the adsorption performance of the molded CO2 adsorbent 11, and conversely, the lower the temperature, the better the adsorption performance; in addition, a large amount of adsorption heat will be generated during the adsorption of CO2 by the molded CO2 adsorbent 11. By providing a channel 111 in the molded CO2 adsorbent 11, and connecting both ends of the channel 111 to the heat exchange pipe 12, during the inflation and exhaust process of the direct contact gas-heat co-storage device, the low-temperature fluid or the high-temperature fluid can flow into the channel 111 through the heat exchange pipe 12, and directly contact with the molded CO2 adsorbent 11 for heat exchange, and the direct contact heat exchange efficiency is high, and the temperature of the molded CO2 adsorbent 11 after heat exchange can be uniformly controlled. During the operation of the device, the exhaust and inflation processes are completed by controlling the opening and closing of the air inlet valve 13 and the air outlet valve 14.

[0027] By utilizing the fact that there is heat change in the process of adsorption and desorption of CO2 by the molded CO2 adsorbent 11, and the adsorption capacity of the molded CO2 adsorbent 11 for CO2 is also affected by temperature changes, the adsorption and desorption process of CO2 is combined with heat storage, and it is possible to store heat by utilizing heat changes while completing CO2 storage, thereby realizing gas-heat co-storage; in addition, by providing channels in the molded CO2 adsorbent 11, and connecting both ends of the channels 111 to the heat exchange pipe 12, the fluid used for heat exchange flows through the channels 111 and directly contacts the molded CO2 adsorbent 11, thereby improving the heat exchange efficiency between the fluid and the molded CO2 adsorbent 11, and ensuring the temperature uniformity of the molded CO2 adsorbent 11, thereby avoiding the problem of low heat exchange efficiency caused by poor thermal conductivity of the porous medium adsorbent, thereby ensuring its gas storage performance.

[0028] For example, the molded CO2 adsorbent 11 is a zeolite honeycomb molded CO2 adsorbent. Zeolite, as an aluminosilicate mineral, has a porous structure, has excellent CO2 adsorption capacity, and is green and environmentally friendly.

[0029] In addition, the air inlet valve 13 and the air outlet valve 14 in the direct contact gas-heat co-storage device are pressure-controlled valves. When the pressure in the gas tank shell 1 changes, the air inlet valve 13 and the air outlet valve 14 can automatically open and close according to the pressure change in the gas tank shell 1, and the air inlet valve 13 and the air outlet valve 14 are also electrically connected to the controller, and the controller can control the opening and closing of the air inlet valve 13 and the air outlet valve 14, thereby improving the degree of automation of the device.

[0030] In order to avoid the mixing of negative pressure air into CO2 gas and ensure the stable operation of the device at a micro-positive pressure, preset upper and lower limits of the micro-positive pressure are set. During the inflation process, the controller controls the opening of the air inlet valve 13 to maintain the micro-positive pressure operation; during the exhaust process, the controller controls the opening of the air outlet valve 14 to discharge CO2 gas and maintain the micro-positive pressure operation.

[0031] The direct contact gas-heat co-storage device also includes a heat storage tank 2 and a cold storage tank 3, wherein heat exchange medium is provided in the heat storage tank 2 and the cold storage tank 3, and the heat exchange medium can exchange heat with the fluid to obtain a high-temperature fluid or a low-temperature fluid, and then the high-temperature fluid or the low-temperature fluid is used to exchange heat with the formed CO2. Exemplarily, the heat exchange medium in the heat storage tank 2 and the cold storage tank 3 is molten salt, and the heat generated by the solar heat storage method is stored in the heat storage tank 2, and then transferred between the heat storage tank 2 and the cold storage tank 3 by the molten salt heat transfer medium, and heat is exchanged with the fluid in the heat exchange pipe 12 to obtain a low-temperature fluid or a high-temperature fluid. The molten salt has high heat transfer performance, low working pressure, and low cost.

[0032] Another embodiment of the present invention provides an energy storage system, including the above-mentioned direct contact gas-heat co-storage device and a heat network.

[0033] In addition, if Figure 3 and Figure 4 As shown, the energy storage system also includes a heat exchanger 4 and a heat pump 5, wherein the heat exchanger 4 is arranged on the heat exchange pipe 12, so that the fluid in the heat exchange pipe 12 and the heat exchange medium in the heat storage tank 2 or the cold storage tank 3 are exchanged in the heat exchanger 4, thereby obtaining a high-temperature fluid or a low-temperature fluid for heating or cooling the gas storage tank; the heat pump 5 is located between different heat exchange pipes 12 on both sides of the gas storage tank shell 1, and the low-temperature heat network return water in the heat network can be further converted into a low-temperature fluid or a high-temperature fluid through the heat pump 5, and the obtained low-temperature fluid or high-temperature fluid is used for heat exchange in the gas storage tank shell 1 and heating of the heat network.

[0034] Specifically, the heat of the direct contact gas-heat co-storage device is changed by the low-temperature fluid or high-temperature fluid in the heat network, so as to perform inflation and exhaust. When exhaust is required, the high-temperature fluid in the heat network is input into the direct contact gas-heat co-storage device for heat exchange, so that the CO2 gas in the molded CO2 adsorbent is desorbed and discharged, and the CO2 molded adsorbent stores the desorption heat and the sensible heat of the adsorbent; when inflation is required, the low-temperature fluid in the heat network is input into the direct contact gas-heat co-storage device for heat exchange, and CO2 gas is input at the same time, so that the molded CO2 adsorbent adsorbs the input CO2 gas, and the adsorption heat generated in this process is taken out by the low-temperature fluid and supplied through the heat network.

[0035] Exemplarily, the exhaust process includes:

[0036] The high-temperature fluid enters the molded CO2 adsorbent 11 through the heat exchange pipe 12 at one end of the pore 111, so that the high-temperature fluid exchanges heat with the molded CO2 adsorbent 11. When the temperature of the molded CO2 adsorbent 11 adsorbing the gas increases, the gas is removed from the molded CO2 adsorbent 11.

[0037] When the gas is removed to a certain extent, the pressure in the gas tank shell 1 increases. When the pressure in the gas tank shell 1 is greater than a preset value, the gas outlet valve 14 is opened to exhaust gas. The opening of the gas outlet valve 14 is controlled to maintain a slight positive pressure in the gas tank shell 1. When the temperature of the molded CO2 adsorbent 11 rises to a predetermined temperature, the high-temperature fluid input is stopped to complete the exhaust process.

[0038] When the temperature and pressure in the gas storage tank shell 1 reach the preset values, the gas outlet valve 14 is closed and the exhaust process ends;

[0039] In this process, the high-temperature fluid after heat exchange with the molded CO2 adsorbent 11 flows out from the heat exchange pipe 12 at the other end, and the CO2 molded adsorbent stores the desorption heat and the sensible heat of the adsorbent.

[0040] The inflation process includes:

[0041] The low-temperature fluid enters the molded CO2 adsorbent 11 through the heat exchange pipe 12 at one end of the channel 111, so that the low-temperature fluid exchanges heat with the molded CO2 adsorbent 11, resulting in a decrease in the temperature of the molded CO2 adsorbent 11;

[0042] When the temperature of the molded CO2 adsorbent 11 drops, the remaining gas in the gas tank shell 1 is adsorbed by the adsorbent, thereby causing the pressure in the gas tank shell 1 to decrease. The air inlet valve 13 is first opened to make the pressure in the gas tank shell 1 slightly positive, and then the opening of the air inlet valve 13 is controlled to maintain the slightly positive pressure in the gas tank shell 1.

[0043] When the temperature and pressure in the gas storage tank shell 1 reach the preset values, the air inlet valve 13 is closed and the charging process ends;

[0044] In this process, when the charged gas is adsorbed by the molded CO2 adsorbent 11, a large amount of heat is released, and the low-temperature fluid after heat exchange with the molded CO2 adsorbent 11 flows out from the heat exchange pipe 12 at the other end and supplies heat through the heat network.

[0045] By applying a direct contact gas-heat co-storage device, the hot and cold circulation device in the heat network can be reasonably utilized to exchange heat with the CO2 adsorbent in the gas-heat co-storage device. While ensuring the gas storage performance, the heat changes of the CO2 adsorbent during the adsorption and desorption of CO2 can also be utilized, which has high economic efficiency.

[0046] The following describes the direct contact gas-heat co-storage device and its exhaust heat exchange and charging heat exchange processes in conjunction with specific embodiments:

[0047] The direct contact gas-heat co-storage device provided in this embodiment includes a gas tank shell 1 made of steel, and the gas tank shell 1 has been heat-insulated. The shell has a diameter of 330 mm and a length of 400 mm. An inlet valve 13 and an outlet valve 14 are respectively arranged on both sides of the gas tank shell 1, which are used to fill or discharge the gas in the gas tank shell 1. The gas tank shell 1 is filled with 25 kg of 13X zeolite honeycomb-shaped CO2 adsorbent, and the adsorbent is evenly distributed with cylindrical channels 111 running through it. The two ends of the channel 111 are respectively connected to two heat exchange pipes 12, and the fluid can enter the channel 111 through the heat exchange pipe 12, so as to directly contact with the adsorbent for heat exchange. Among them, the heat exchange pipes 12 at both ends of the channel 111 are connected to the pipeline in the heat network, and the low-temperature fluid and high-temperature fluid in the heat network enter the device for heat exchange to achieve temperature control.

[0048] When the direct contact gas-heat co-storage device is assembled, it is inflated for the first time. First, the inside of the gas tank is purged with nitrogen, and the pressure in the gas tank is pumped to -0.999 bar through a vacuum pump to remove the remaining gas in the gas tank. Then, pre-inflating is performed. The air inlet valve is opened to introduce CO2 gas. At the same time, cold water at a temperature of 5°C is introduced into the heat exchange pipe to cool the heat generated during the CO2 adsorption process. When the gas tank reaches an equilibrium state of 293K and 1 bar, the pre-inflating process is completed, and about 3200L CO2 gas is introduced. Then the direct contact gas-heat co-storage device is combined with the heat network, heat exchanger 4, and heat pump 5 to form an energy storage system.

[0049] like Figure 3 As shown, the exhaust process includes:

[0050] During the exhaust stage, the high-temperature molten salt in the heat storage tank exchanges heat with the return water from the heat network in the heat exchanger 4 to generate high-temperature steam of 200°C, which enters the pores 111 of the molded CO2 adsorbent 11 through the heat exchange pipe 12, uniformly heats the molded CO2 adsorbent 11 and stores heat at the same time, so that the CO2 gas in the adsorbent is removed. When the CO2 gas is removed to a certain extent, the pressure in the gas storage tank will rise. When it is higher than the set pressure of 1 bar, the outlet valve 14 will be opened to discharge the CO2 gas; continue to introduce high-temperature steam. When the temperature in the gas storage tank reaches 200°C and the pressure is 1 bar, stop supplying steam for heating, close the outlet valve 14, and end the exhaust and heat storage process. The gas storage tank discharges about 2800L of gas.

[0051] like Figure 4 As shown, the inflation process includes:

[0052] At the beginning of the gas charging heat storage, the temperature of the adsorbent is still the set temperature of 200°C in the exhaust stage. At this time, the heat network return water with a temperature of 30°C is input into the heat exchange pipe 12, so that the low-temperature heat network return water exchanges heat with the molded CO2 adsorbent 11, and the temperature of the molded CO2 adsorbent 11 is reduced. At the same time, the temperature of the heat network return water rises, and the heated heat network return water can be used for heat supply in the heat network. As the temperature of the adsorbent is reduced, the CO2 adsorption capacity of the adsorbent can be improved.

[0053] Furthermore, the return water from the heat network is input into the heat pump 5, and high-temperature hot water and low-temperature cold water are obtained through the heat pump 5. The low-temperature cold water of the heat pump with a temperature of 5°C is input into the heat exchange pipe 12, which causes the temperature inside the gas storage tank to drop rapidly, so that the remaining CO2 gas in the tank body is further adsorbed. During the inflation process, the air inlet valve 13 is first opened to make the pressure in the gas storage tank shell 1 a slight positive pressure of 0.01 bar, and then the opening of the air inlet valve 13 is controlled to maintain the slight positive pressure in the gas storage tank shell 1; when the temperature of the molded CO2 adsorbent is lower than the lower limit of the temperature of 298K, 2800L of CO2 gas can be filled in, and the inflation is stopped to complete the inflation heat storage process.

[0054] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An energy storage system, It is characterized in that The invention comprises a heat exchanger (4), a direct contact gas-heat co-storage device and a heat network, wherein the direct contact gas-heat co-storage device comprises a gas storage tank shell (1), wherein a molded CO 2 Adsorbent (11), the shaped CO 2 The adsorbent (11) is provided with a pore (111), both ends of the pore (111) are connected to the heat exchange pipe (12), and the fluid is suitable for passing through the heat exchange pipe (12) and the pore (111) and the shaped CO 2 The gas storage tank (1) is provided with an air inlet valve (13) and an air outlet valve (14) on both sides of the gas storage tank shell (1); the air inlet valve (13) and the air outlet valve (14) are pressure control valves; the gas storage tank (2) and the cold storage tank (3) are also included; the heat storage tank (2) and the cold storage tank (3) are suitable for exchanging heat with the fluid in the heat exchange pipe (12); the heat exchange medium in the heat storage tank (2) and the cold storage tank (3) is molten salt; the heat storage tank (2) or the cold storage tank (3) exchanges heat with the fluid in the heat exchange pipe (12) through the heat exchanger (4); the gas storage tank (5) is also included; the heat network return water in the heat network is suitable for being converted into a low-temperature fluid or a high-temperature fluid through the heat pump (5); The heat of the direct contact gas-heat co-storage device is changed by the low-temperature fluid or high-temperature fluid in the heat network, so as to perform inflation and exhaust. When exhaust is required, the high-temperature fluid in the heat network is input into the direct contact gas-heat co-storage device for heat exchange, so that the formed CO 2 CO in the adsorbent (11) 2 The gas is discharged after desorption, and the formed CO 2 The adsorbent (11) stores the adsorption heat and the sensible heat of the adsorbent; when inflation is required, the low-temperature fluid in the heat network is input into the direct contact gas-heat co-storage device for heat exchange, and CO is input at the same time. 2 Gas, forming CO 2 The adsorbent (11) adsorbs the input CO 2 The adsorption heat and sensible heat of the adsorbent generated in the process are taken out by the low-temperature fluid and then supplied through the heat network.

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