Carbon dioxide dry ice energy and material gradient utilization system

Abstract

The utility model provides an energy and material gradient utilization system for preparing dry ice from carbon dioxide. The energy and material gradient utilization system comprises a carbon capture system and a dry ice preparation system, the carbon capture system is connected with the dry ice making system through a heat exchange pipeline, and specifically comprises a first-stage flue gas cooling heat exchanger, a second-stage flue gas cooling heat exchanger, an absorption tower, a buffer tank, a compressor, a refrigeration dryer, a refrigeration heat exchanger, an adsorption tower, a drying tower, a liquefaction refrigeration system, a storage tank and a dry ice making machine; the low temperature of the dry ice tail gas is utilized in a gradient mode through a heat exchange pipeline, and carbon dioxide finished product gas and initial flue gas for carbon capture are cooled; the cold blowing air for adsorption and drying is utilized in a gradient manner, the cooling capacity of the cold blowing air is recycled, and damage of the super-cooled cold blowing air to the adsorbent and the drying agent is prevented.

Description

Technical Field

[0001] The utility model relates to the field of flue gas waste heat utilization, and mainly relates to a cascade utilization system for the energy and materials of carbon dioxide to dry ice. Background Technique

[0002] Based on the working principle of the dry ice machine, the carbon dioxide utilization rate of the dry ice production system is often only about 40%, and about 60% of the carbon dioxide captured from the flue gas by consuming a large amount of energy will be wasted during the dry ice production process. Therefore, there is an urgent need for a technology to maximize the recovery and utilization rate of carbon dioxide materials with the lowest energy consumption, and at the same time make full use of the cold energy of carbon dioxide itself to further reduce the energy consumption of the entire carbon capture and liquefaction to dry ice system, so as to activate the cascade utilization of energy and materials of the carbon capture system and the liquefaction refrigeration to dry ice system.

[0003] Chinese Patent CN207738460U - A waste gas recovery system during dry ice production, which relates to a waste gas recovery system during dry ice production, including a precooler, a buffer device, a compressor, a first dryer, a second dryer, a liquefaction unit, a separator, a regeneration device and a heater. The buffer device connects the precooler and the compressor, the liquefaction unit connects the precooler and the separator, the first dryer and the second dryer are both connected to the compressor, the heater and the precooler, the regeneration device is connected to the heater, the first dryer and the second dryer are both provided with vent pipes, and the separator is respectively provided with a vent pipe and a drain pipe.

[0004] Chinese Patent CN117146438A - Flue gas waste heat utilization process, which relates to the fields of chemical engineering and chemical environmental protection technology, and specifically relates to a flue gas waste heat utilization process and system that can play an energy-saving and consumption-reducing role. The process includes: first recovering the waste heat of the flue gas with washing water to obtain hot water, then introducing the hot water into a driving refrigeration device to obtain cold water, and then using the cold water in the carbon dioxide liquefaction section; wherein, the carbon dioxide liquefaction section includes temperature reduction and water removal, compression, drying and condensation, and a part of the cold water is used as the cold source in the temperature reduction and water removal process, and the other part is used to cool the refrigerant in the condensation process.

[0005] The Chinese patent CN207738460U mainly sets up a precooler to recover the cold of dry ice tail gas, but does not take into account the discontinuity of dry ice production and cannot ensure the continuity of the precooler, which leads to a great impact on the stability of the back-end liquefied refrigeration system and the fluctuation of the water dew point of the finished carbon dioxide, resulting in the instability of the purity of the finished carbon dioxide. Secondly, the precooler is set at the front end of the compressor. Since the compressor will generate a lot of heat during operation, the precooled carbon dioxide will be heated again, causing the recovered cold to be lost again. At the same time, the non-condensable gas is discharged continuously, and a large amount of carbon dioxide will be carried along with it. Therefore, this patent only plays the role of recovering part of the carbon dioxide material when the energy consumption is doubled.

[0006] Chinese patent CN117146438A uses hot flue gas to heat the washing water of the water washing tower, and then uses the washing water to provide driving heat for the heat-driven refrigeration equipment to obtain cold water. This patent requires that the spray water be heated to a temperature that can serve as a driving heat source for the refrigeration equipment, while also having a good cooling effect on the flue gas. Such a temperature setting will result in extremely low temperature and pressure of the entire water washing tower, which will have a great demand for the spray heat exchange space of the water washing tower, resulting in an increase in the investment cost of the tower itself. Contents of utility model

[0007] In order to solve the above-mentioned problems existing in the prior art, the utility model provides a system for the cascade utilization of energy and materials for making dry ice from carbon dioxide. First, the low temperature of the dry ice tail gas is used in stages to cool down the finished carbon dioxide gas and the initial flue gas for carbon capture; secondly, the cold blow air used for adsorption and drying is used in stages, which not only recovers the coldness of this part of the cold blow air, but also prevents the damage of the overcooled cold blow air to the adsorbent and the desiccant. At the same time, the finished carbon dioxide gas that has utilized all the coldness returns to the front end of the buffer tank to continue to be compressed and liquefied to refrigerate and make dry ice. In this way, the cascade utilization of the energy and materials of the dry ice tail gas and the cold blow air in the system is completed, and at the same time, the front-end flue gas carbon capture process is linked, and the effect of the traditional carbon capture flue gas cooling water washing tower system is optimized. In this way, the spraying water volume and heat exchange space of the water washing tower system can be reduced, thereby further reducing the energy consumption and investment of the carbon capture system.

[0008] The technical solution of the utility model is as follows: a carbon dioxide dry ice energy and material cascade utilization system, including a carbon capture system and a dry ice making system; the carbon capture system is connected to the dry ice making system via a heat exchange pipeline;

[0009] The carbon capture system comprises: a primary flue gas cooling heat exchanger, a secondary flue gas cooling heat exchanger and an absorption tower are sequentially connected along the direction of the flue gas; the flue gas is high-temperature flue gas from the water washing tower, and the high-temperature flue gas enters the absorption tower after being cooled by the primary flue gas cooling heat exchanger and the secondary flue gas cooling heat exchanger;

[0010] The dry ice production system includes: along the flue gas direction, a buffer tank, a compressor, a cold dryer, a cold drying heat exchanger, an adsorption tower, a drying tower, a liquefied refrigeration system, a storage tank and a dry ice maker are connected in sequence; the flue gas is carbon dioxide gas.

[0011] Preferably, the primary flue gas cooling heat exchanger, the secondary flue gas cooling heat exchanger and the cold drying heat exchanger are respectively provided with a primary heat exchange pipeline, a secondary heat exchange pipeline and a cold drying heat exchange pipeline;

[0012] The connection mode of the carbon capture system and the dry ice production system through the heat exchange pipeline includes that along the carbon dioxide gas direction, the flue gas outlet of the dry ice maker is connected to the primary heat exchange pipeline of the primary flue gas cooling heat exchanger through the cold drying heat exchange pipeline, and then connected to the buffer tank.

[0013] Preferably, a certain proportion of carbon dioxide gas generated by ice making in the dry ice maker returns to the front end of the buffer tank through the heat exchange pipeline.

[0014] Preferably, a heater is further included. The connection mode of the carbon capture system and the dry ice production system through the heat exchange pipeline further includes that along the carbon dioxide gas direction, the liquefied refrigeration system is connected to the heater through the secondary heat exchange pipeline of the secondary flue gas cooling heat exchanger, and the flue gas outlet of the heater is respectively connected to the injection gas sources of the adsorption tower and the drying tower.

[0015] Preferably, the refrigeration exhaust gas in the liquefied refrigeration system enters the adsorption tower system and the drying tower respectively according to 5% of the gas volume after being heated by the secondary heat exchange pipeline and the heater.

[0016] Preferably, the outlet of the injection gas source of the adsorption tower is emptied, and the injection gas source of the drying tower is connected to the flue gas inlet of the buffer tank.

[0017] Preferably, the refrigeration exhaust gas in the liquefied refrigeration system consists of non-condensable gas and pure carbon dioxide gas.

[0018] Preferably, the adsorption tower and the drying tower operate intermittently. When one tower is in the working state, the other tower is blown for regeneration, and then cold blown and standby.

[0019] Preferably, an organic amine solution for absorbing carbon dioxide in high-temperature flue gas is arranged in the absorption tower.

[0020] Compared with the prior art, the beneficial effects of the present utility model are:

[0021] 1. A carbon dioxide to dry ice energy and material cascade utilization system proposed by the present utility model conducts "two-line multi-direction" linkage through the needs of the dry ice production tail gas and the liquefied refrigeration tail gas for temperature increase and the needs of the carbon capture raw flue gas and the carbon dioxide finished gas for temperature decrease, achieving both the effect of energy cascade utilization and the recovery effect of about 60% of the finished gas.

[0022] 2. A low-water-consumption and low-power-consumption temperature reduction process for the raw flue gas in carbon capture proposed by the present utility model weakens the temperature reduction effect of the water washing tower on the flue gas by using the closed-loop primary flue gas temperature reduction heat exchanger and the secondary flue gas temperature reduction heat exchanger to cool the flue gas, thus reducing the overall water volume required for flue gas temperature reduction. At the same time, since the cold source is the dry ice tail gas with self-pressure and the liquefied refrigeration exhaust, there is no need to set up a pumping device, so the overall power demand for flue gas temperature reduction is also reduced.

[0023] 3. A liquefied refrigeration exhaust energy cascade recovery process proposed by the present utility model has the effect of secondarily cooling the raw flue gas by the liquefied refrigeration exhaust. At the same time, since this exhaust absorbs part of the heat of the raw flue gas, during the hot blow process of the adsorption drying tower system, the heating power consumption of the heater can be reduced, and during the cold blow process of the adsorption drying tower, the impact of the too-low low-temperature exhaust on the adsorption desiccant just completed by the hot blow is also avoided, extending the service life of the adsorption desiccant;

[0024] 4. A regeneration near-zero gas consumption process for the adsorption drying system proposed by the present utility model. Since the liquefied refrigeration exhaust contains some non-condensable gases, and the adsorption tower will carry out various impurity gases during the hot blow and cold blow processes, only 5% of the gas volume is distributed into the adsorption tower and directly discharged to the outside. In this way, while discharging the non-condensable gases as much as possible, the excessive loss of the finished carbon dioxide gas can be prevented, achieving near-zero loss of the finished carbon dioxide gas. Description of the Drawings

[0025] Figure 1 It is a system schematic diagram of the present utility model.

[0026] The reference numerals in the figure are represented as: 1 - absorption tower; 2 - primary flue gas temperature reduction heat exchanger; 3 - secondary flue gas temperature reduction heat exchanger; 4 - buffer tank; 5 - compressor; 6 - cold dryer; 7 - cold drying heat exchanger; 8 - adsorption tower; 9 - drying tower; 10 - heater; 11 - liquefied refrigeration system; 12 - storage tank; 13 - dry ice maker. Detailed Embodiment

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1 , the present invention provides the following technical solutions: An energy and material cascade utilization system for producing dry ice from carbon dioxide, including an absorption tower 1, a primary flue gas cooling heat exchanger 2, a secondary flue gas cooling heat exchanger 3, a buffer tank 4, a compressor 5, a cold dryer 6, a cold drying heat exchanger 7, an adsorption tower 8, a drying tower 9, a heater 10, a liquefaction refrigeration system 11, and a dry ice maker 13;

[0029] The present invention includes a first system, i.e., a carbon capture system: The high-temperature flue gas from the water washing tower exchanges heat through the primary flue gas cooling heat exchanger 2 and the secondary flue gas cooling heat exchanger 3, and then enters the absorption tower 1 containing the organic amine solution for carbon capture. The temperature reduction in this system is achieved by the heat exchange between the low-temperature medium in the heat exchange pipeline of the cooling heat exchanger and the high-temperature flue gas, and the low-temperature medium is the carbon dioxide gas refrigerated by the liquefaction refrigeration system 11 in the second system, i.e., the dry ice production system, of the present invention.

[0030] The second system of the present invention, i.e., the dry ice production system: The carbon dioxide gas for producing dry ice enters the compressor 5 through the buffer tank 4 for compression, then enters the cold dryer 6 and the cold drying heat exchanger 7 to remove the moisture in the gas, and then enters the absorption tower 8 and the drying tower 9 to remove the moisture in the wet materials or gas by adsorption, blowing dry or condensation, so as to achieve the purpose of drying. The purified carbon dioxide gas enters the liquefaction refrigeration system 11 for liquefaction refrigeration to become carbon dioxide liquid, which is stored in the storage tank 12, and then the dry ice maker 13 is used to turn the liquefied carbon dioxide into solid dry ice.

[0031] Refrigeration exhaust gas will be generated in the liquefaction refrigeration system, and this part of the refrigeration exhaust gas includes part of the non-condensable gas and part of the unliquefied pure carbon dioxide gas. 10% of the refrigeration exhaust gas is used as the heat exchange medium of the secondary flue gas temperature heat exchanger 3 in the carbon capture system through the secondary heat exchange pipeline. The refrigeration exhaust gas after heat exchange can be heated by a heater and then enter the adsorption tower 8 system and the drying tower 9 respectively according to 5% of the gas volume as the blowing gas source. The adsorption tower 8 and the drying tower 9 operate intermittently in a dual-tower mode. When one tower is in the working state, the other tower is regenerated by hot purging, and then cold blown and left standing for standby, and so on in a cycle. The gas entering the drying tower 8 is led back to the front end of the buffer tank 4 to continue the compression and liquefaction process for producing dry ice, while the gas entering the adsorption tower 8 is discharged into the atmosphere after working. This is the energy and material cascade utilization system for carbon dioxide liquefaction refrigeration exhaust gas

[0032] In the dry ice making machine 13, about 60% of the carbon dioxide gas generated during dry ice production is used as a heat exchange medium. It returns to the front end of the buffer tank 4 through the heat exchange pipes in the cold dryer heat exchanger 7 and the heat exchange pipes in the primary flue gas temperature exchanger 2 and re-enters the compression and liquefaction dry ice production process. This is the energy and material cascade utilization system for dry ice production tail gas.

[0033] The working principle of the present utility model is as follows:

[0034] The energy and material utilization lines are divided into two lines: the energy and material cascade utilization system for dry ice production tail gas and the energy and material cascade utilization system for the exhaust gas of carbon dioxide liquefaction refrigeration.

[0035] The energy and material cascade utilization system for dry ice production tail gas specifically refers to using about 60% of the dry ice production tail gas. The dry ice tail gas first enters the cold dryer heat exchanger 7 arranged at the rear end of the cold dryer 6 to cool and dry the carbon dioxide finished gas, thereby reducing the water dew point of the carbon dioxide finished gas and ensuring that the purity of the liquefied carbon dioxide reaches the designed standard value. After heat exchange, there is still some cold energy remaining in the dry ice tail gas, so it is continuously introduced into the primary flue gas cooling heat exchanger 2 in the carbon capture system to initially cool the relatively high-temperature flue gas from the water washing tower. The dry ice tail gas after secondary heat exchange then all enters the buffer tank 4 to continue the compression refrigeration liquefaction.

[0036] The energy and material cascade utilization system for the exhaust gas of carbon dioxide liquefaction refrigeration specifically refers to using the non-condensable gas in the liquefaction refrigeration system. First, this part of the gas is introduced into the secondary flue gas cooling heat exchanger 3, which can supplement the cooling effect of the primary flue gas cooling heat exchanger 2 and take further cooling supplement measures for the relatively high-temperature flue gas when the dry ice production system is shut down or the cooling of the primary flue gas cooling heat exchanger cannot reach the expected target. At the same time, the gas is introduced into the adsorption tower and the inlet of the drying tower 9 system at a flow rate of 5% each, and then all the carbon dioxide entering the drying tower 9 enters the buffer tank 4 to continue the compression refrigeration liquefaction.

[0037] Through the utilization of the cooling capacity of the above two lines, the achievable effects are as follows: (1) Firstly, during the operation period of the dry ice production system, the cold dryer 6 can be shut down or operated under low load conditions. The cold drying heat exchanger 7 temporarily replaces the function of the cold dryer 6 to achieve the same cold drying effect on the finished carbon dioxide gas, thereby reducing the operating power consumption of the cold dryer 6. Secondly, the two-stage heat exchanger can further cool the relatively high-temperature flue gas from the water washing tower, supplementing the low-temperature demand of the flue gas that cannot be achieved or is difficult to achieve due to insufficient cold source temperature in the water washing tower. At the same time, since the cooling capacity recovery and utilization are all heat exchanges of closed heat exchangers, and the dry ice tail gas itself has a certain pressure, there is no need for additional pumping. This can not only reduce the required space size of the spray tower but also reduce the specification selection of the spray pump system, thus reducing the corresponding investment and operating power consumption while reducing the size of the corresponding investment; (2) Compared with directly introducing the liquefied refrigeration exhaust gas into the reheater and then into the adsorption drying tower 9 system, after heat exchange and temperature rise in the secondary flue gas cooling heat exchanger 3 first, the heating power consumption of the heater 10 can be reduced. At the same time, during the cold blow stage, the temperature difference between the hot blowing gas and the cold blowing gas is reduced, avoiding the conversion of the adsorbent and desiccant between extremely hot and extremely cold states, prolonging the service life, and maximizing the full recovery of the cooling capacity of the liquefied refrigeration exhaust gas and its own materials.

[0038] The above description is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A carbon dioxide dry ice energy and material cascade utilization system, characterized in that: It includes a carbon capture system and a dry ice making system; the carbon capture system is connected to the dry ice making system via a heat exchange pipe; The carbon capture system comprises: a primary flue gas cooling heat exchanger, a secondary flue gas cooling heat exchanger and an absorption tower are sequentially connected along the flue gas direction; the flue gas is high-temperature flue gas from a water washing tower, and the high-temperature flue gas enters the absorption tower after being cooled by the primary flue gas cooling heat exchanger and the secondary flue gas cooling heat exchanger; The dry ice making system comprises: a buffer tank, a compressor, a cold dryer, a cold and dry heat exchanger, an adsorption tower, a drying tower, a liquefaction refrigeration system, a storage tank and a dry ice making machine are sequentially connected along the direction of the flue gas; the flue gas is carbon dioxide gas.

2. A carbon dioxide to dry ice energy and material cascade utilization system according to claim 1, characterized in that: The primary flue gas cooling heat exchanger, the secondary flue gas cooling heat exchanger and the cold and dry heat exchanger are respectively provided with a primary heat exchange pipeline, a secondary heat exchange pipeline and a cold and dry heat exchange pipeline; The carbon capture system is connected to the dry ice making system via a heat exchange pipe, wherein the flue gas outlet of the dry ice making machine is connected to the primary heat exchange pipe of the primary flue gas cooling heat exchanger via the cold and dry heat exchange pipe along the direction of the carbon dioxide gas, and then connected to the buffer tank.

3. A carbon dioxide to dry ice energy and material cascade utilization system according to claim 2, characterized in that: A certain proportion of carbon dioxide gas generated by ice making in the dry ice making machine returns to the front end of the buffer tank through the heat exchange pipeline.

4. The energy and material cascade utilization system for making dry ice from carbon dioxide according to claim 2, characterized in that: It also includes a heater, and the carbon capture system is connected to the dry ice making system via a heat exchange pipe, and the liquefaction refrigeration system is connected to the heater via a secondary heat exchange pipe of the secondary flue gas cooling heat exchanger along the direction of the carbon dioxide gas, and the flue gas outlet of the heater is respectively connected to the injection gas source of the adsorption tower and the drying tower.

5. The energy and material cascade utilization system for making dry ice from carbon dioxide according to claim 3, characterized in that: The refrigeration exhaust gas in the liquefied refrigeration system enters the adsorption tower system and the drying tower at a gas volume of 5% after being heated by the secondary heat exchange pipeline and the heater.

6. A carbon dioxide to dry ice energy and material cascade utilization system according to claim 5, characterized in that: The outlet of the spray air source of the adsorption tower is emptied, and the spray air source of the drying tower is connected to the smoke inlet of the buffer tank.

7. The energy and material cascade utilization system for making dry ice from carbon dioxide according to claim 5, characterized in that: The refrigeration exhaust gas in the liquefied refrigeration system consists of non-condensable gas and pure carbon dioxide gas.

8. The energy and material cascade utilization system for making dry ice from carbon dioxide according to claim 4, characterized in that: The adsorption tower and the drying tower are operated intermittently. When one of the towers is in operation, the other tower is sprayed for regeneration and then cold-blown for standby use.

9. The energy and material cascade utilization system for making dry ice from carbon dioxide according to claim 1, characterized in that: The absorption tower is provided with an organic amine liquid for absorbing carbon dioxide in the high-temperature flue gas.

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