Carbon dioxide purification device

Abstract

The utility model relates to a carbon dioxide purifying device which comprises a rectifying tower, the rectifying tower comprises a tower body, a tower bottom heater, a first packing layer and a second packing layer, a cold source channel of the tower bottom heater is communicated with an inner cavity of the tower body, and the rectifying tower further comprises a first nitrogen conveying pipe, the first nitrogen conveying pipe is provided with a buffer tank, a nitrogen compressor unit, the pressurizing end of the turbo expander, the main heat exchanger and the expansion end of the turbo expander, the expansion end of the turbo expander, the main heat exchanger and the buffer tank are provided with nitrogen return pipes, and the first nitrogen conveying pipe on the inner side of the main heat exchanger is provided with a liquefaction conveying pipe. The liquefaction conveying pipe is communicated with a tower body above the first packing layer, a first raw material gas conveying pipe is arranged on the tower bottom heater and the main heat exchanger, and a second raw material gas conveying pipe is arranged on the tower body and the tower bottom heater. And reducing the temperature of the carbon dioxide feed gas entering the rectifying tower to participate in rectification. The utility model has the advantages of convenient use and wide market prospect.

Description

Technical Field

[0001] The utility model relates to the field of carbon dioxide purification equipment, in particular to a carbon dioxide purification device. Background Art

[0002] Carbon dioxide is a colorless, tasteless, and odorless gas at room temperature. Commonly known as carbonic acid gas, it is also called carbonic anhydride or carbonic anhydride. At room temperature, it is a colorless, odorless gas with a density slightly greater than that of air. It dissolves in water to form carbonic acid. Solid carbon dioxide, commonly known as dry ice, absorbs large amounts of heat during sublimation and is therefore used as a refrigerant. There are two main methods for industrially producing carbon dioxide: calcination and fermentation gas recovery. The calcination method uses high-temperature calcination of calcium carbonate to produce carbon dioxide feed gas. The fermentation gas recovery method uses water to wash, remove impurities, and compress the crude carbon dioxide gas produced during the ethanol fermentation process to produce the carbon dioxide feed gas. The carbon dioxide feed gas produced in both processes requires further purification to obtain high-purity carbon dioxide liquid for subsequent processing and utilization.

[0003] Since the impurities contained in the carbon dioxide feed gas produced by high-temperature calcined calcium carbonate are non-condensable gases such as carbon monoxide and nitrogen, distillation is an extremely effective method for purifying the carbon dioxide feed gas produced by high-temperature calcined calcium carbonate. The specific device for distilling the carbon dioxide feed gas includes a distillation tower and a reboiler located at the bottom of the distillation tower. The reboiler heats the liquid carbon dioxide to continuously vaporize the impurities within it. The carbon dioxide component in the vaporized gas is then continuously transported to the condensate at the top of the distillation tower for liquefaction, thereby producing high-purity carbon dioxide liquid at the top of the distillation tower for external transportation as an intermediate product.

[0004] However, there is still room for improvement in the existing technology. Specifically, the carbon dioxide delivered to the distillation tower is too hot, so a large amount of condensate needs to be transported at the top of the tower so that the carbon dioxide raw gas can be liquefied when entering the distillation tower, and the reboiler at the bottom of the tower requires continuous heat source transportation to enable the liquid carbon dioxide at the bottom of the tower to be continuously evaporated. The need for a large amount of condensate at the top of the tower and the need for continuous heat source transportation at the bottom of the tower both require the manufacturer to pay additional energy costs to be achieved. Therefore, from the perspective of energy consumption, lowering the temperature of the carbon dioxide raw gas entering the distillation tower for distillation can reduce the amount of cold source continuously transported to the top of the distillation tower, thereby achieving the energy cost paid by the enterprise in purifying the carbon dioxide raw gas, thereby reducing the enterprise's operating costs and meeting market demand. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a carbon dioxide purification device capable of reducing the temperature of the carbon dioxide feed gas entering a distillation tower for distillation, so as to overcome the defects in the prior art.

[0006] The technical solution adopted by the utility model is as follows: a carbon dioxide purification device includes a distillation tower, the distillation tower includes a tower body, a bottom heater arranged at the bottom end of the tower body, and a first packing layer and a second packing layer arranged in sequence in the direction away from the bottom heater to the direction close to the bottom heater in the inner cavity of the tower body, the cold source channel of the bottom heater is connected to the inner cavity of the tower body, the first nitrogen delivery pipe is provided with a buffer tank and a nitrogen compressor unit in sequence along the direction from the inlet end to the outlet end of the first nitrogen delivery pipe , the boost end of the turbine expander, the main heat exchanger and the expansion end of the turbine expander, a nitrogen reflux pipe is provided on the expansion end of the turbine expander, the main heat exchanger and the buffer tank, the inlet end of the liquefied gas delivery pipe is provided on the first nitrogen delivery pipe on the inside of the main heat exchanger, the outlet end of the liquefied gas delivery pipe is connected to the tower body above the first packing layer, the inlet end of the heat source channel of the bottom heater and the main heat exchanger are provided with a first raw gas delivery pipe, and a second raw gas delivery pipe is provided between the tower body between the first packing layer and the second packing layer and the outlet end of the heat source channel of the bottom heater.

[0007] Preferably, a gas-liquid separation tank is provided on the liquefied gas delivery pipe, a second nitrogen delivery pipe is provided on the nitrogen reflux pipe between the expansion end of the turbine expander and the main heat exchanger and on the top of the gas-liquid separation tank, and a first regulating valve is provided on the first nitrogen delivery pipe between the main heat exchanger and the expansion end of the turbine expander and the liquefied gas delivery pipe between the gas-liquid separation tank and the tower body.

[0008] Preferably, liquid level sensors are respectively provided on the cold source channels of the gas-liquid separation tank and the tower bottom heater.

[0009] Preferably, the second nitrogen delivery pipe is provided with a first pressure sensor and a second regulating valve in sequence along a direction from close to the gas-liquid separation tank to away from the gas-liquid separation tank.

[0010] Preferably, a temperature sensor is provided on the nitrogen reflux pipe between the buffer tank and the main heat exchanger.

[0011] Preferably, the second raw gas delivery pipe is provided with a second pressure sensor and a third regulating valve in sequence along the direction from close to the bottom heater to away from the bottom heater, and a carbon dioxide compressor unit is provided on the first raw gas delivery pipe on the side of the main heat exchanger away from the bottom heater.

[0012] Preferably, a dirty nitrogen gas delivery pipe is provided on the tower body and the main heat exchanger above the outlet end of the liquefied gas delivery pipe, an inlet end of the carbon dioxide delivery pipe is provided on the bottom end of the cold source channel of the tower bottom heater, a subcooler is provided between the carbon dioxide delivery pipe and the dirty nitrogen gas delivery pipe, and the carbon dioxide delivery pipe between the subcooler and the outlet end of the carbon dioxide delivery pipe is provided with a fourth regulating valve, a booster pump, an online chromatograph, the inlet end of the discharge pipe and a first stop valve in sequence along the direction from close to the subcooler to away from the subcooler, and a second stop valve is provided on the discharge pipe.

[0013] The beneficial effects of the utility model are as follows: first, the utility model utilizes pressurized carbon dioxide feed gas as a heat source of a tower bottom heater to heat the medium in a cold source channel of the tower bottom heater, thereby reducing the temperature of the carbon dioxide feed gas entering the distillation tower to participate in distillation, thereby reducing the amount of liquid nitrogen used as a condensate, and thus achieving energy saving.

[0014] Secondly, the second raw gas delivery pipe described in the present invention is sequentially provided with a second pressure sensor and a third regulating valve along the direction away from the bottom heater to close to the bottom heater. The installation of the second pressure sensor facilitates the feedback of pressure parameters.

[0015] Again, the carbon dioxide delivery pipe between the subcooler and the outlet end of the carbon dioxide delivery pipe of the utility model is provided with a fourth regulating valve, a booster pump, an online chromatograph, the inlet end of the discharge pipe and a first stop valve in sequence along the direction from close to the subcooler to away from the subcooler. The online chromatograph is installed to facilitate the feedback of component parameters.

[0016] The utility model has the advantages of simple structure, convenient operation, ingenious design, greatly improved work efficiency, good social and economic benefits, and is a product that is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the present utility model. DETAILED DESCRIPTION

[0018] like Figure 1As shown, a carbon dioxide purification device includes a distillation tower, the distillation tower includes a tower body 1, a bottom heater 2 provided at the bottom end of the tower body 1, and a first packing layer 3 and a second packing layer 4 provided in sequence in the inner cavity of the tower body 1 in a direction away from the bottom heater 2 to the direction close to the bottom heater 2, the cold source channel of the bottom heater 2 is connected to the inner cavity of the tower body 1, and further includes a first nitrogen delivery pipe 5, the first nitrogen delivery pipe 5 is provided with a buffer tank 6, a nitrogen compressor unit 7, and a turbo expander 8 in sequence along the direction from the inlet end of the first nitrogen delivery pipe 5 to the outlet end of the first nitrogen delivery pipe 5. A nitrogen reflux pipe 10 is provided on the expansion end of the main heat exchanger 9 and the expansion end of the turbine expander 8. The expansion end of the turbine expander 8, the main heat exchanger 9, and the buffer tank 6. The inlet end of the liquefied gas delivery pipe 11 is provided on the first nitrogen delivery pipe 5 inside the main heat exchanger 9. The outlet end of the liquefied gas delivery pipe 11 is connected to the tower body 1 above the first packing layer 3. A first raw gas delivery pipe 12 is provided on the inlet end of the heat source channel of the tower bottom heater 2 and the main heat exchanger 9. A second raw gas delivery pipe 13 is provided between the tower body 1 between the first packing layer 3 and the second packing layer 4 and the outlet end of the heat source channel of the tower bottom heater 2. A pressure relief valve 34 is provided on the top of the buffer tank 6.

[0019] A gas-liquid separator tank 14 is installed on the liquefied gas delivery pipe 11. A second nitrogen delivery pipe 15 is installed on the nitrogen return pipe 10 between the expansion end of the turbine expander 8 and the main heat exchanger 9, and on the top of the gas-liquid separator tank 14. A first regulating valve 16 is installed on the first nitrogen delivery pipe 5 between the main heat exchanger 9 and the expansion end of the turbine expander 8, and on the liquefied gas delivery pipe 11 between the gas-liquid separator tank 14 and the tower body 1. Liquid level sensors 17 are installed on the gas-liquid separator tank 14 and the cold source channel of the tower bottom heater 2, respectively. The installation of these sensors facilitates feedback of liquid level parameters. The second nitrogen delivery pipe 15 is sequentially installed with a first pressure sensor 18 and a second regulating valve 19, extending from near the gas-liquid separator tank 14 to away from it. A temperature sensor 20 is installed on the nitrogen return pipe 10 between the buffer tank 6 and the main heat exchanger 9, facilitating feedback of temperature parameters. A heat source channel for the auxiliary heat exchanger 21 is provided on the first nitrogen delivery pipe 5 between the boosting end of the turboexpander 8 and the main heat exchanger 9. A second pressure sensor 22 and a third regulating valve 23 are sequentially provided on the second feed gas delivery pipe 13 from near the bottom heater 2 to away from the bottom heater 2. A carbon dioxide compressor unit 24 is provided on the first feed gas delivery pipe 12 on the side of the main heat exchanger 9 away from the bottom heater 2.

[0020] A dirty nitrogen gas delivery pipe 25 is provided on the tower body 1 and the main heat exchanger 9 above the outlet end of the liquefied gas delivery pipe 11, and the inlet end of the carbon dioxide delivery pipe 26 is provided at the bottom end of the cold source channel of the tower bottom heater 2. A subcooler 27 is provided between the carbon dioxide delivery pipe 26 and the dirty nitrogen gas delivery pipe 25. The carbon dioxide delivery pipe 26 between the subcooler 27 and the outlet end of the carbon dioxide delivery pipe 26 is provided with a fourth regulating valve 28, a booster pump 29, an online chromatograph 30, the inlet end of the discharge pipe 31 and a first stop valve 32 in sequence along the direction from close to the subcooler 27 to away from the subcooler 27, and the discharge pipe 31 is provided with a second stop valve 33.

[0021] The method of using this product is as follows: Figure 1 As shown, the following steps are included:

[0022] S1. The first nitrogen delivery pipe 5 receives the finished nitrogen continuously delivered by the upstream air separation system and then delivers it to the buffer tank 6. It first passes through the nitrogen compressor unit 7 for the first pressurization and is then delivered to the boosting end of the turbine expander 8 for the second pressurization. It is then delivered to the heat source channel of the auxiliary heat exchanger 21 and the medium continuously delivered to the cold source channel of the auxiliary heat exchanger 21 for countercurrent heat exchange. The finished nitrogen after the second pressurization is discharged from the heat source channel of the auxiliary heat exchanger 21 and is then delivered to the first heat source channel of the main heat exchanger 9 and the cold source continuously delivered to the main heat exchanger 9 for heat exchange. After being discharged from the high-temperature area of ​​the main heat exchanger 9, it is delivered to the boosting end of the turbine expander 8 for expansion and cooling and is returned to the buffer tank 6 through the nitrogen reflux pipe 10 to form a nitrogen cycle.

[0023] S2. When the temperature of the temperature sensor 20 reaches the preset temperature, the second regulating valve 19 is opened. At this time, the finished nitrogen gas after the second pressurization enters the first heat source channel of the main heat exchanger 9 and is divided into two parts. The first part of the finished nitrogen gas after the second pressurization is still discharged from the high-temperature area of ​​the main heat exchanger 9 and transported to the pressurization end of the turbine expander 8 for expansion and cooling, and then returned to the buffer tank 6 through the nitrogen return pipe 10 to maintain nitrogen circulation. The second part of the finished nitrogen gas after the second pressurization is discharged from the low-temperature end of the main heat exchanger 9. The part of the finished nitrogen gas after the second pressurization discharged from the low-temperature end of the main heat exchanger 9 is liquefied to form a gas-liquid mixture. The gas-liquid mixture is transported to the gas-liquid separation tank 14 through the liquefaction delivery pipe 11 for gas-liquid separation. The liquid phase portion is liquid nitrogen and the gas phase portion is nitrogen. The liquid phase portion remains in the gas-liquid separation tank 14 for temporary storage, and the gas phase portion is returned to the nitrogen return pipe 10 through the second nitrogen delivery pipe 15 to participate in the nitrogen circulation.

[0024] S3. When the liquid level sensor 17 on the gas-liquid separation tank 14 reaches the preset liquid level height, the product completes the cold capacity preparation for the distillation of the carbon dioxide raw gas. The first raw gas delivery pipe 12 receives the carbon dioxide raw gas delivered from the upstream. The carbon dioxide raw gas is compressed by the carbon dioxide compressor unit 24 and sent to the second heat source channel of the main heat exchanger 9 and the cold source continuously delivered to the main heat exchanger 9 for heat exchange. After that, it is discharged from the high-temperature area of ​​the main heat exchanger 9 and then delivered to the heat source channel of the tower bottom heater 2 and the medium of the cold source channel of the tower bottom heater 2 for heat exchange. After that, it is discharged from the heat source channel of the tower bottom heater 2 through the second raw gas delivery pipe 13 and sent into the inner cavity of the tower body 1 from the tower body 1 between the first packing layer 3 and the second packing layer 4 to participate in distillation.

[0025] At the same time, the first regulating valve 16 on the liquefied delivery pipe 11 is opened. At this time, the liquid nitrogen stored in the gas-liquid separation tank 14 enters the inner cavity of the tower body 1 from the tower body 1 above the first packing layer 3 and is used as condensate.

[0026] When the carbon dioxide raw gas enters the inner cavity of the tower body 1 to form a first ascending airflow, and performs the first direct heat exchange with the continuously descending condensate in the first packing layer 3, it is liquefied to form a descending liquid flow. In the process of the first direct heat exchange, the carbon dioxide component in the carbon dioxide raw gas is liquefied, while the carbon monoxide contained in the carbon dioxide raw gas remains. The other liquid nitrogen accompanying the condensate is vaporized to form dirty nitrogen gas and transported to the dirty nitrogen gas transport pipe 25. The dirty nitrogen gas transport pipe 25 first transports the gas to the heat source channel of the subcooler 27 and the medium continuously transported to the cold source channel of the subcooler 27 for countercurrent heat exchange, and then transports the gas to the first cold source channel of the main heat exchanger 9 and the heat source continuously transported to the main heat exchanger 9 and is discharged after heat exchange; the descending liquid The flow continues to descend along the inner cavity of the tower body 1 and performs a second direct heat exchange with the second ascending air flow in the second packing layer 4. The descending liquid flow contains a large amount of liquid carbon dioxide and a small amount of liquid nitrogen. During the second direct heat exchange process, the small amount of liquid nitrogen is vaporized to form a third ascending air flow, which continues to ascend along the inner cavity of the tower body 1 and then merges into the first ascending air flow; while the carbon dioxide in the descending liquid flow continues to remain in liquid form and continues to descend, and finally falls into the cold source channel of the tower bottom heater 2 and is continuously supplied to the medium of the heat source channel of the tower bottom heater 2 for indirect heat exchange. The impurities in the liquid medium in the cold source channel of the tower bottom heater 2 are further evaporated to form a second ascending air flow and continue to ascend along the inner cavity of the tower body 1.

[0027] S4. After the liquid level of the cold source channel of the bottom heater 2 reaches a preset height, the booster pump 29 is turned on. At this time, the cold source channel of the bottom heater 2 continuously transports liquid carbon dioxide outward. The liquid carbon dioxide passes through the heat source channel of the cooler 27 and the cold source continuously transported to the subcooler 27 in turn for countercurrent heat exchange. After being pressurized by the booster pump 29, the components are fed back by the online chromatograph 30 and then discharged through the discharge pipe 31. When the components fed back by the online chromatograph 30 reach a preset range, the second stop valve 33 is closed and the first stop valve 32 is opened. At this time, the liquid carbon dioxide after the components are fed back by the online chromatograph 30 is transported to the carbon dioxide storage tank through the carbon dioxide delivery pipe 26 for standby use.

[0028] Through this embodiment, this product uses the pressurized carbon dioxide feed gas as the heat source of the bottom heater 2 to heat the medium in the cold source channel of the bottom heater 2, thereby reducing the temperature of the carbon dioxide feed gas entering the distillation tower to participate in distillation, thereby reducing the use of liquid nitrogen as a condensate, and thus achieving energy saving.

[0029] The embodiments described above are only preferred embodiments of the present invention and do not limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structure, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A carbon dioxide purification device, comprising a distillation tower, wherein the distillation tower comprises a tower body (1), a bottom heater (2) provided at the bottom end of the tower body (1), and a first packing layer (3) and a second packing layer (4) provided in sequence in the inner cavity of the tower body (1) in a direction away from the bottom heater (2) and closer to the bottom heater (2), a cold source channel of the bottom heater (2) and the inner cavity of the tower body (1) being connected, characterized in that: The first nitrogen delivery pipe (5) is provided with a buffer tank (6), a nitrogen compressor unit (7), a boosting end of a turbine expander (8), a main heat exchanger (9) and an expansion end of the turbine expander (8) in sequence from the inlet end of the first nitrogen delivery pipe (5) to the outlet end of the first nitrogen delivery pipe (5). A nitrogen reflux pipe (10) is provided on the expansion end of the turbine expander (8), the main heat exchanger (9) and the buffer tank (6). The inlet end of the liquefied gas delivery pipe (11) is provided on the first nitrogen delivery pipe (5) on the side, the outlet end of the liquefied gas delivery pipe (11) is connected to the tower body (1) above the first packing layer (3), the inlet end of the heat source channel of the tower bottom heater (2) and the main heat exchanger (9) are provided with a first raw gas delivery pipe (12), and the second raw gas delivery pipe (13) is provided between the tower body (1) between the first packing layer (3) and the second packing layer (4) and the outlet end of the heat source channel of the tower bottom heater (2).

2. The carbon dioxide purification device according to claim 1, characterized in that: The liquefied gas delivery pipe (11) is provided with a gas-liquid separation tank (14), a second nitrogen delivery pipe (15) is provided on the nitrogen return pipe (10) between the expansion end of the turbine expander (8) and the main heat exchanger (9) and on the top of the gas-liquid separation tank (14), and a first regulating valve (16) is provided on the first nitrogen delivery pipe (5) between the main heat exchanger (9) and the expansion end of the turbine expander (8) and the liquefied gas delivery pipe (11) between the gas-liquid separation tank (14) and the tower body (1).

3. The carbon dioxide purification device according to claim 2, characterized in that: Liquid level sensors (17) are respectively provided on the cold source channels of the gas-liquid separation tank (14) and the tower bottom heater (2).

4. The carbon dioxide purification device according to claim 2, characterized in that: The second nitrogen delivery pipe (15) is provided with a first pressure sensor (18) and a second regulating valve (19) in sequence along a direction from close to the gas-liquid separation tank (14) to far away from the gas-liquid separation tank (14).

5. The carbon dioxide purification device according to claim 1, characterized in that: A temperature sensor (20) is provided on the nitrogen return pipe (10) between the buffer tank (6) and the main heat exchanger (9).

6. The carbon dioxide purification device according to claim 1, characterized in that: The second raw gas delivery pipe (13) is provided with a second pressure sensor (22) and a third regulating valve (23) in sequence along a direction from close to the tower bottom heater (2) to away from the tower bottom heater (2), and a carbon dioxide compressor unit (24) is provided on the first raw gas delivery pipe (12) on the side of the main heat exchanger (9) away from the tower bottom heater (2).

7. The carbon dioxide purification device according to claim 1, characterized in that: A dirty nitrogen gas delivery pipe (25) is provided on the tower body (1) above the outlet end of the liquefied gas delivery pipe (11) and the main heat exchanger (9), an inlet end of a carbon dioxide delivery pipe (26) is provided on the bottom end of the cold source channel of the tower bottom heater (2), a subcooler (27) is provided between the carbon dioxide delivery pipe (26) and the dirty nitrogen gas delivery pipe (25), and a fourth regulating valve (28), a booster pump (29), an online chromatograph (30), an inlet end of a discharge pipe (31) and a first stop valve (32) are provided in sequence on the carbon dioxide delivery pipe (26) between the subcooler (27) and the outlet end of the carbon dioxide delivery pipe (26) along a direction from close to the subcooler (27) to away from the subcooler (27), and a second stop valve (33) is provided on the discharge pipe (31).

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