Device and process method for removing high sulfur content in carbon dioxide tail gas

Abstract

The invention relates to a device and a process method for removing high sulfur content in carbon dioxide tail gas. Comprising a low-temperature methanol washing section; a tail gas pipeline of the low-temperature methanol washing section is connected with a first inlet of a de-heavy rectifying tower through a first compressor and a first channel of a fourth heat exchanger, and a gas phase outlet of the de-heavy rectifying tower is connected with an inlet of a fine desulfurization tower through a first heat exchange channel of a first heat exchanger and a supercharger; a gas phase outlet of the fine desulfurization tower is connected with an inlet of the light component removal rectifying tower through a first heat exchange channel of the water cooler and a second heat exchange channel of the first heat exchanger; a liquid phase outlet of the light component removal rectifying tower is connected with the carbon dioxide storage tank; the method has the advantages of saving energy, reducing emission, saving equipment investment, reducing use of desulfurizer and lowering production and labor cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide production, and specifically relates to a device and a process method for removing high sulfur content in carbon dioxide tail gas. Background Art

[0002] Carbon dioxide is a carbon oxide with the chemical formula CO2 and a chemical formula weight of 44.0095. It is a colorless and odorless gas at room temperature and pressure, and its aqueous solution has a slightly sour taste. It has a wide range of uses. Gaseous carbon dioxide is used for carbonating soft drinks, chemical processing, food preservation, inert protection in chemical and food processing, welding gas, and plant growth stimulant.

[0003] In summary, carbon dioxide has a wide range of uses. At the same time, the existing low-temperature methanol washing section produces a large amount of tail gas, which has the characteristics of large gas volume, low carbon dioxide purity and high sulfur content (its content range is 10-90ppm). Based on this, the tail gas of the traditional low-temperature methanol washing section is vented tail gas. With the requirement for carbon reduction, how to recycle it has become a technical problem that needs to be solved urgently; in traditional technology, the treatment of low-sulfur carbon dioxide generally adopts the "sandwich" process, that is, first remove hydrogen sulfide, then remove carbonyl sulfide (hydrolysis, hydrogen sulfide is generated), and finally remove hydrogen sulfide; based on this, in order to treat carbon dioxide gas with high sulfur content, multiple groups of "sandwich" processes are used in series. This method has the defects of a large number of equipment, large investment, and the need to regularly replace the desulfurizer, and high production and labor costs. Summary of the invention

[0004] The object of the present invention is to provide a device and a process for removing high sulfur content in carbon dioxide tail gas, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section, wherein the tail gas pipeline of the low-temperature methanol washing section is connected to the first inlet of a heavy desulfurization tower through a first compressor and a first channel of a fourth heat exchanger, the gas phase outlet of the heavy desulfurization tower is connected to the inlet of a fine desulfurization tower through the first heat exchange channel of the first heat exchanger and a booster, the gas phase outlet of the fine desulfurization tower is connected to the inlet of a light desulfurization tower through the first heat exchange channel of a water cooler and the second heat exchange channel of the first heat exchanger, and the liquid phase outlet of the light desulfurization tower is connected to a carbon dioxide storage tank.

[0007] The beneficial effects of the present invention are as follows: the present invention abandons the process line of traditional technology for treating carbon dioxide gas with high sulfur content, and utilizes a deheaving distillation tower to treat the vented tail gas and pre-remove the vented tail gas, which can reduce the desulfurization load of the fine desulfurization tower without the need for graded desulfurization, greatly simplifying the process line, reducing investment and production and labor costs; at the same time, it adopts a low-pressure roughing and high-pressure refining graded impurity removal process to reduce the work of the compressor and reduce the difficulty of impurity separation.

[0008] Preferably, the gas phase outlet of the light-removal distillation tower is connected to the first heat exchange channel of the second heat exchanger, the liquid phase outlet of the first heat exchange channel of the second heat exchanger is connected to the reflux ports of the heavy-removal distillation tower and the light-removal distillation tower respectively, the gas phase outlet of the first heat exchange channel of the second heat exchanger is connected to the first heat exchange channel of the third heat exchanger, the liquid phase outlet of the first heat exchange channel of the third heat exchanger is connected to the reflux port of the heavy-removal distillation tower, and the gas phase outlet of the first heat exchange channel of the third heat exchanger is connected to the exhaust gas treatment device.

[0009] Preferably, the liquid phase outlet of the deheaving distillation tower is connected to a tail gas treatment device.

[0010] Preferably, a tee is provided between the liquid phase outlet of the light-removal distillation tower and the carbon dioxide storage tank, the third end of the tee is connected to the second heat exchange channel of the third heat exchanger, the outlet of the second heat exchange channel of the third heat exchanger is connected to the second compressor through the second channel of the fourth heat exchanger, and the outlet of the second compressor is connected to the second inlet of the heavy-removal distillation tower.

[0011] Preferably, the second heat exchange channel of the second heat exchanger is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier, which is connected to the third channel of the fourth heat exchanger through a buffer tank, and the third channel outlet of the fourth heat exchanger is connected to the second heat exchange channel of the second heat exchanger; the second heat exchange channel outlet of the second heat exchanger is connected to the booster liquefier inlet.

[0012] Preferably, a throttle valve is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger.

[0013] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0014] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section enters the first compressor for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger for heat exchange, and enters the de-heavy distillation tower for distillation after heat exchange; the pressure of the tail gas after entering the first compressor is 6-12 bar, and the temperature after passing through the first channel of the fourth heat exchanger is 9-20°C;

[0015] Step 2: the tail gas enters the de-heavy distillation tower and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger from the gas phase outlet at the top of the de-heavy distillation tower; the heavy components removed by the de-heavy distillation tower mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0016] Step 3: The temperature of the gas phase entering the first heat exchange channel of the first heat exchanger is 20-40°C after heat exchange. The gas phase with a temperature of 20-40°C is passed through a booster to increase the pressure of the raw gas to 22-32 bar and then enters the fine desulfurization tower for desulfurization, reducing the sulfur content in the gas phase to below 0.1ppm;

[0017] Step 4: the gas phase after desulfurization through the fine desulfurization tower enters the first heat exchange channel of the water cooler for heat exchange, enters the second heat exchange channel of the first heat exchanger for further heat exchange, and enters the light desulfurization distillation tower for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler is 40 to 45°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger is -22 to -14°C;

[0018] Step 5: The raw gas entering the de-light distillation tower undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-light distillation tower. The carbon dioxide in the raw gas is continuously condensed and liquefied, and is enriched at the bottom of the tower, and enters the carbon dioxide storage tank from the liquid phase outlet of the de-light distillation tower.

[0019] Preferably, in the step 5, a part of the liquid phase at the bottom of the light removal distillation tower enters the carbon dioxide storage tank through a tee, and the other part is reduced in pressure to 6-9 Bar by a throttle valve and then enters the second heat exchange channel of the third heat exchanger as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger. After the heat exchange, it enters the second channel of the fourth heat exchanger for heat exchange again, and after the heat exchange again, it is compressed by the second compressor and enters the heavy removal distillation tower for the production of carbon dioxide in the system.

[0020] Preferably, in the step 5, the gas phase at the top of the light removal distillation tower enters the first heat exchange channel of the second heat exchanger, and part of the gas phase is condensed and enters the heavy removal distillation tower and the light removal distillation tower respectively as reflux liquid; the remaining gas phase in the first heat exchange channel of the second heat exchanger enters the first heat exchange channel of the third heat exchanger for further condensation and liquefaction, and the condensed and liquefied liquid phase enters the heavy removal distillation tower as reflux liquid, and the unliquefied gas phase in the first heat exchange channel of the third heat exchanger enters the exhaust gas treatment device; the bottom liquid of the heavy removal distillation tower in the step 2 also enters the exhaust gas treatment device for treatment.

[0021] Preferably, the refrigerant in the second heat exchange channel of the second heat exchanger provides coldness to the first heat exchange channel of the second heat exchanger and then enters the boost liquefier, and after being pressurized by the buffer tank, enters the third channel of the fourth heat exchanger for heat exchange, and the refrigerant after heat exchange enters the second heat exchange channel of the second heat exchanger to form a cycle; the refrigerant is R717, R134a, R507; the refrigeration temperature of the refrigerant is -18 to -42°C.

[0022] According to the above scheme, a device and process for removing high sulfur content in carbon dioxide tail gas are prepared, which are mainly used for desulfurizing the original vented tail gas in the low-temperature methanol washing section and purifying it to produce carbon dioxide, so that the product can be applied to industrial welding, oil field flooding, food processing and other fields; so as to achieve energy conservation and emission reduction, save equipment investment, reduce the use of desulfurizers and reduce production and labor costs. The present invention innovatively adopts a de-heavy distillation tower to pre-desulfurize the vented tail gas, first removes carbonyl sulfide that is easily hydrolyzed in the later stage, and on this basis removes part of hydrogen sulfide, so as to reduce the adsorption desulfurization load of the fine desulfurization tower, and there is no need to use a separation tower. The method of stage desulfurization greatly simplifies the process route and reduces investment, production and labor costs. At the same time, the present invention adopts cascade refrigeration of carbon dioxide and the second refrigerant to achieve three-stage refrigeration temperature zone, and recovers the cold capacity of the cold logistics in a cascade manner, while avoiding the loss of cold capacity caused by overcooling of the hot logistics, which has a significant energy-saving effect. Furthermore, the carbon dioxide product is used as a refrigerant to create a low-temperature zone, which improves the product extraction rate. At the same time, the refrigerant carbon dioxide returns to the distillation system after gasification, which has the characteristic of no waste of raw materials. From a macroscopic point of view, the present invention adopts a low-pressure roughing and high-pressure refining graded impurity removal process to reduce the work of the compressor and reduce the difficulty of impurity separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention.

[0024] In the figure: 1. first compressor; 2. fourth heat exchanger; 3. deheavy fractionation tower; 4. first heat exchanger; 5. booster; 6. fine desulfurization tower; 7. water cooler; 8. delight fractionation tower; 9. second heat exchanger; 10. third heat exchanger; 11. carbon dioxide storage tank; 12. second compressor; 13. tail gas treatment device; 14. booster liquefier; 15. throttle valve; 16. buffer tank; 17. low-temperature methanol washing section. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] Reference Figure 1As shown, the present invention is a device and a process method for removing high sulfur content in carbon dioxide tail gas, wherein the device comprises a low-temperature methanol washing section 17, wherein the tail gas pipeline of the low-temperature methanol washing section 17 is connected to the first inlet of a heavy removal distillation tower 3 through a first compressor 1 and a first channel of a fourth heat exchanger 2, the gas phase outlet of the heavy removal distillation tower 3 is connected to the inlet of a refined desulfurization tower 6 through a first heat exchange channel of a first heat exchanger 4 and a booster 5, the gas phase outlet of the refined desulfurization tower 6 is connected to the inlet of a light removal distillation tower 8 through a first heat exchange channel of a water cooler 7 and a second heat exchange channel of the first heat exchanger 4, and the liquid phase outlet of the light removal distillation tower 8 is connected to a carbon dioxide storage tank 11. The tail gas in the low-temperature methanol washing section 17 of the present invention enters the de-heavy distillation tower 3 for pre-distillation treatment on the basis of compression and heat exchange cooling, so as to remove the heavy substances in the tail gas. The heavy substances include alcohol, water, part of hydrogen sulfide, carbonyl sulfide and other impurities in the tail gas. In particular, the removal of water and carbonyl sulfide can avoid the hydrolysis of carbonyl sulfide to generate hydrogen sulfide in the later stage, thereby avoiding the use of traditional purification methods. At the same time, the desulfurization load of the fine desulfurization tower 6 can be reduced by pre-distillation of the de-heavy distillation tower. The fine desulfurization tower 6 is a packed distillation tower, in which the packing in the tower can be The use of zinc oxide, activated carbon, etc. can effectively remove sulfur from the tail gas, reduce the sulfur content in the tail gas to below 0.1ppm, and can also increase the operating time of the fine desulfurization tower 6; further, the present invention is provided with a water cooler 7 and a first heat exchanger 4 in front of the light desulfurization distillation tower 8 to exchange heat and cool the gas phase passing through the fine desulfurization tower 6 to meet the operating requirements of the light desulfurization distillation tower 8 and further improve the purity of carbon dioxide; the above-mentioned arrangement can reduce the desulfurization load of the fine desulfurization tower without the need for graded desulfurization, greatly simplify the process route, and reduce investment and production and labor costs.

[0027] Furthermore, the gas phase outlet of the de-light distillation tower 8 is connected to the first heat exchange channel of the second heat exchanger 9, the liquid phase outlet of the first heat exchange channel of the second heat exchanger 9 is respectively connected to the reflux ports of the de-heavy distillation tower 3 and the de-light distillation tower 8, the gas phase outlet of the first heat exchange channel of the second heat exchanger 9 is connected to the first heat exchange channel of the third heat exchanger 10, the liquid phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the reflux port of the de-heavy distillation tower 3, and the gas phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the exhaust gas treatment device 13. The present invention performs graded condensation treatment on the gas phase of the de-lightening distillation tower 8, recovers the condensed liquid phase and uses it as the reflux liquid of the de-heaving distillation tower 3 and the de-lightening distillation tower 8, and allows the non-condensable gas to enter the tail gas treatment device 13 for treatment; graded condensation can be achieved in the above process, which can not only achieve the characteristic of saving refrigeration, but also fully recover and reuse the gas phase output by the de-lightening distillation tower 8; the de-lightening distillation tower 8 described in the present invention is mainly used to remove light component impurities such as oxygen, nitrogen, hydrocarbons, carbon monoxide, etc. in the raw gas.

[0028] Furthermore, the liquid phase outlet of the de-heavy distillation tower 3 is connected to the tail gas treatment device 13. The tail gas treatment device 13 mainly includes a gas-liquid separator, a catalyst, an exhaust pipe, etc., which can be directly purchased on the market, so it is not described in detail.

[0029] Furthermore, a tee is provided between the liquid phase outlet of the light-removing distillation tower 8 and the carbon dioxide storage tank 11, the third end of the tee is connected to the second heat exchange channel of the third heat exchanger 10, the outlet of the second heat exchange channel of the third heat exchanger 10 is connected to the second compressor 12 through the second channel of the fourth heat exchanger 2, and the outlet of the second compressor 12 is connected to the second inlet of the heavy-removing distillation tower 3. The present invention uses carbon dioxide product as a refrigerant to create a low-temperature zone, improves the product extraction rate, and the refrigerant carbon dioxide is returned to the distillation system after gasification, without waste of raw materials, and can also achieve the characteristics of saving cold and reducing energy consumption.

[0030] Furthermore, the second heat exchange channel of the second heat exchanger 9 is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier 14, and the booster liquefier 14 is connected to the third channel of the fourth heat exchanger 2 through a buffer tank 16, and the outlet of the third channel of the fourth heat exchanger 2 is connected to the second heat exchange channel of the second heat exchanger 9; the outlet of the second heat exchange channel of the second heat exchanger 9 is connected to the inlet of the booster liquefier 14. The present invention adopts cascade refrigeration of carbon dioxide and the second refrigerant to achieve a two-stage refrigeration temperature zone, and the temperature in the second heat exchanger 9 is about: -22 to -14°C; the temperature in the third heat exchanger 10 is about: -53 to -48°C, and the cold flow is recovered in stages, while avoiding the loss of cold caused by overcooling of the hot flow, which has a significant energy-saving effect; the booster liquefier 14 described in the present invention includes a refrigeration unit, a heat exchanger, etc., which is conventional equipment and can be directly purchased on the market, and the structure is not repeated.

[0031] Furthermore, a throttle valve 15 is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger 10 .

[0032] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0033] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section 17 enters the first compressor 1 for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger 2 for heat exchange, and enters the de-weighting distillation tower 3 for distillation after heat exchange; the pressure of the tail gas after entering the first compressor 1 is: 6-12 bar, and the temperature after passing through the first channel of the fourth heat exchanger 2 is 9-20°C;

[0034] Step 2: the tail gas enters the de-heavy distillation tower 3 and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger 4 from the gas phase outlet at the top of the de-heavy distillation tower 3; the heavy components removed by the de-heavy distillation tower 3 mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower 3 is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0035] Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger 4 is 20-40°C. The gas phase with a temperature of 20-40°C passes through the booster 5 to increase the pressure of the raw gas to 22-32 bar and then enters the fine desulfurization tower 6 for desulfurization, reducing the sulfur content in the gas phase to below 0.1ppm;

[0036] Step 4: the gas phase after desulfurization through the fine desulfurization tower 6 enters the first heat exchange channel of the water cooler 7 for heat exchange, enters the second heat exchange channel of the first heat exchanger 4 for further heat exchange, and enters the light desulfurization distillation tower 8 for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler 7 is 40 to 45°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger 4 is -22 to -14°C;

[0037] Step 5: The raw gas entering the de-lightening distillation tower 8 undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower 8, and the carbon dioxide in the raw gas is continuously condensed and liquefied, enriched at the bottom of the tower, and enters the carbon dioxide storage tank 11 from the liquid phase outlet of the de-lightening distillation tower 8.

[0038] Furthermore, in the step 5, a part of the liquid phase at the bottom of the light removal distillation tower 8 enters the carbon dioxide storage tank 11 through a tee, and the other part is reduced in pressure to 6-9 Bar through a throttle valve 15 and then enters the second heat exchange channel of the third heat exchanger 10 as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger 10. After the heat exchange, it enters the second channel of the fourth heat exchanger 2 for heat exchange again, and after the heat exchange again, it is compressed by the second compressor 12 and enters the heavy removal distillation tower 3 for the production of carbon dioxide in the system.

[0039] Furthermore, in the step 5, the gas phase at the top of the light removal distillation tower 8 enters the first heat exchange channel of the second heat exchanger 9, and part of the gas phase is condensed and enters the heavy removal distillation tower 3 and the light removal distillation tower 8 as reflux liquid respectively; the remaining gas phase in the first heat exchange channel of the second heat exchanger 9 enters the first heat exchange channel of the third heat exchanger 10 for further condensation and liquefaction, and the condensed and liquefied liquid phase enters the heavy removal distillation tower 3 as reflux liquid, and the unliquefied gas phase in the first heat exchange channel of the third heat exchanger 10 enters the exhaust gas treatment device 13; the bottom liquid of the heavy removal distillation tower 3 in the step 2 also enters the exhaust gas treatment device 13 for treatment.

[0040] Furthermore, the refrigerant in the second heat exchange channel of the second heat exchanger 9 provides coldness for the first heat exchange channel of the second heat exchanger 9 and then enters the boost liquefier 14, is pressurized by the buffer tank 16, and then enters the third channel of the fourth heat exchanger 2 for heat exchange, and the refrigerant after heat exchange enters the second heat exchange channel of the second heat exchanger 9 to form a cycle; the refrigerant is R717, R134a, R507; the refrigeration temperature of the refrigerant is -18 to -42°C.

[0041] In order to explain the present invention more clearly, it is further described in conjunction with specific embodiments. The specific embodiments are as follows:

[0042] Example 1

[0043] A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section 17, wherein the tail gas pipeline of the low-temperature methanol washing section 17 is connected to the first inlet of a heavy-removal distillation tower 3 through a first compressor 1 and a first channel of a fourth heat exchanger 2, the gas phase outlet of the heavy-removal distillation tower 3 is connected to the inlet of a refined desulfurization tower 6 through a first heat exchange channel of a first heat exchanger 4 and a booster 5, the gas phase outlet of the refined desulfurization tower 6 is connected to the inlet of a light-removal distillation tower 8 through a first heat exchange channel of a water cooler 7 and a second heat exchange channel of the first heat exchanger 4, and the liquid phase outlet of the light-removal distillation tower 8 is connected to a carbon dioxide storage tank 11. The gas phase outlet of the de-light distillation tower 8 is connected to the first heat exchange channel of the second heat exchanger 9, and the liquid phase outlet of the first heat exchange channel of the second heat exchanger 9 is respectively connected to the reflux ports of the de-heavy distillation tower 3 and the de-light distillation tower 8. The gas phase outlet of the first heat exchange channel of the second heat exchanger 9 is connected to the first heat exchange channel of the third heat exchanger 10, and the liquid phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the reflux port of the de-heavy distillation tower 3. The gas phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the tail gas treatment device 13. The liquid phase outlet of the de-heavy distillation tower 3 is connected to the tail gas treatment device 13. A tee is arranged between the liquid phase outlet of the de-light distillation tower 8 and the carbon dioxide storage tank 11, and the third end of the tee is connected to the second heat exchange channel of the third heat exchanger 10. The outlet of the second heat exchange channel of the third heat exchanger 10 is connected to the second compressor 12 through the second channel of the fourth heat exchanger 2, and the outlet of the second compressor 12 is connected to the second inlet of the de-heavy distillation tower 3. The second heat exchange channel of the second heat exchanger 9 is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier 14, which is connected to the third channel of the fourth heat exchanger 2 through a buffer tank 16, and the third channel outlet of the fourth heat exchanger 2 is connected to the second heat exchange channel of the second heat exchanger 9; the second heat exchange channel outlet of the second heat exchanger 9 is connected to the inlet of the booster liquefier 14. A throttle valve 15 is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger 10.

[0044] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0045] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section 17 enters the first compressor 1 for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger 2 for heat exchange, and enters the de-heavy distillation tower 3 for distillation after heat exchange; the pressure of the tail gas after entering the first compressor 1 is: 6 bar, and the temperature after passing through the first channel of the fourth heat exchanger 2 is 9°C;

[0046] Step 2: the tail gas enters the de-heavy distillation tower 3 and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger 4 from the gas phase outlet at the top of the de-heavy distillation tower 3; the heavy components removed by the de-heavy distillation tower 3 mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower 3 is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0047] Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger 4 is 20°C. The gas phase with a temperature of 20°C passes through the booster 5 to increase the pressure of the raw gas to 22 bar and then enters the fine desulfurization tower 6 for desulfurization, reducing the sulfur content in the gas phase to below 0.1ppm;

[0048] Step 4: the gas phase after desulfurization through the fine desulfurization tower 6 enters the first heat exchange channel of the water cooler 7 for heat exchange, enters the second heat exchange channel of the first heat exchanger 4 for further heat exchange, and enters the light desulfurization distillation tower 8 for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler 7 is 40°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger 4 is -14°C;

[0049] Step 5: The raw gas entering the de-lightening distillation tower 8 undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower 8, and the carbon dioxide in the raw gas is continuously condensed and liquefied, enriched at the bottom of the tower, and enters the carbon dioxide storage tank 11 from the liquid phase outlet of the de-lightening distillation tower 8.

[0050] Example 2

[0051] A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section 17, wherein the tail gas pipeline of the low-temperature methanol washing section 17 is connected to the first inlet of a heavy-removal distillation tower 3 through a first compressor 1 and a first channel of a fourth heat exchanger 2, the gas phase outlet of the heavy-removal distillation tower 3 is connected to the inlet of a refined desulfurization tower 6 through a first heat exchange channel of a first heat exchanger 4 and a booster 5, the gas phase outlet of the refined desulfurization tower 6 is connected to the inlet of a light-removal distillation tower 8 through a first heat exchange channel of a water cooler 7 and a second heat exchange channel of the first heat exchanger 4, and the liquid phase outlet of the light-removal distillation tower 8 is connected to a carbon dioxide storage tank 11. The gas phase outlet of the de-light distillation tower 8 is connected to the first heat exchange channel of the second heat exchanger 9, and the liquid phase outlet of the first heat exchange channel of the second heat exchanger 9 is respectively connected to the reflux ports of the de-heavy distillation tower 3 and the de-light distillation tower 8. The gas phase outlet of the first heat exchange channel of the second heat exchanger 9 is connected to the first heat exchange channel of the third heat exchanger 10, and the liquid phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the reflux port of the de-heavy distillation tower 3. The gas phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the tail gas treatment device 13. The liquid phase outlet of the de-heavy distillation tower 3 is connected to the tail gas treatment device 13. A tee is arranged between the liquid phase outlet of the de-light distillation tower 8 and the carbon dioxide storage tank 11, and the third end of the tee is connected to the second heat exchange channel of the third heat exchanger 10. The outlet of the second heat exchange channel of the third heat exchanger 10 is connected to the second compressor 12 through the second channel of the fourth heat exchanger 2, and the outlet of the second compressor 12 is connected to the second inlet of the de-heavy distillation tower 3. The second heat exchange channel of the second heat exchanger 9 is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier 14, which is connected to the third channel of the fourth heat exchanger 2 through a buffer tank 16, and the third channel outlet of the fourth heat exchanger 2 is connected to the second heat exchange channel of the second heat exchanger 9; the second heat exchange channel outlet of the second heat exchanger 9 is connected to the inlet of the booster liquefier 14. A throttle valve 15 is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger 10.

[0052] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0053] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section 17 enters the first compressor 1 for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger 2 for heat exchange, and enters the de-heavy distillation tower 3 for distillation after heat exchange; the pressure of the tail gas after entering the first compressor 1 is: 12 bar, and the temperature after passing through the first channel of the fourth heat exchanger 2 is 20°C;

[0054] Step 2: the tail gas enters the de-heavy distillation tower 3 and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger 4 from the gas phase outlet at the top of the de-heavy distillation tower 3; the heavy components removed by the de-heavy distillation tower 3 mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower 3 is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0055] Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger 4 is 40°C. The gas phase at a temperature of 40°C passes through the booster 5 to increase the pressure of the raw gas to 32 bar and then enters the fine desulfurization tower 6 for desulfurization, reducing the sulfur content in the gas phase to below 0.1 ppm;

[0056] Step 4: the gas phase after desulfurization through the fine desulfurization tower 6 enters the first heat exchange channel of the water cooler 7 for heat exchange, enters the second heat exchange channel of the first heat exchanger 4 for further heat exchange, and enters the light desulfurization distillation tower 8 for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler 7 is 45°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger 4 is -22°C;

[0057] Step 5: The raw gas entering the de-lightening distillation tower 8 undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower 8, and the carbon dioxide in the raw gas is continuously condensed and liquefied, enriched at the bottom of the tower, and enters the carbon dioxide storage tank 11 from the liquid phase outlet of the de-lightening distillation tower 8.

[0058] Furthermore, in the step 5, a part of the liquid phase at the bottom of the light removal distillation tower 8 enters the carbon dioxide storage tank 11 through a tee, and the other part is reduced in pressure to 6 Bar through a throttle valve 15 and then enters the second heat exchange channel of the third heat exchanger 10 as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger 10. After the heat exchange, it enters the second channel of the fourth heat exchanger 2 for heat exchange again, and after the heat exchange again, it is compressed by the second compressor 12 and enters the heavy removal distillation tower 3 for the production of carbon dioxide in the system.

[0059] Example 3

[0060] A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section 17, wherein the tail gas pipeline of the low-temperature methanol washing section 17 is connected to the first inlet of a heavy-removal distillation tower 3 through a first compressor 1 and a first channel of a fourth heat exchanger 2, the gas phase outlet of the heavy-removal distillation tower 3 is connected to the inlet of a refined desulfurization tower 6 through a first heat exchange channel of a first heat exchanger 4 and a booster 5, the gas phase outlet of the refined desulfurization tower 6 is connected to the inlet of a light-removal distillation tower 8 through a first heat exchange channel of a water cooler 7 and a second heat exchange channel of the first heat exchanger 4, and the liquid phase outlet of the light-removal distillation tower 8 is connected to a carbon dioxide storage tank 11. The gas phase outlet of the de-light distillation tower 8 is connected to the first heat exchange channel of the second heat exchanger 9, and the liquid phase outlet of the first heat exchange channel of the second heat exchanger 9 is respectively connected to the reflux ports of the de-heavy distillation tower 3 and the de-light distillation tower 8. The gas phase outlet of the first heat exchange channel of the second heat exchanger 9 is connected to the first heat exchange channel of the third heat exchanger 10, and the liquid phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the reflux port of the de-heavy distillation tower 3. The gas phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the tail gas treatment device 13. The liquid phase outlet of the de-heavy distillation tower 3 is connected to the tail gas treatment device 13. A tee is arranged between the liquid phase outlet of the de-light distillation tower 8 and the carbon dioxide storage tank 11, and the third end of the tee is connected to the second heat exchange channel of the third heat exchanger 10. The outlet of the second heat exchange channel of the third heat exchanger 10 is connected to the second compressor 12 through the second channel of the fourth heat exchanger 2, and the outlet of the second compressor 12 is connected to the second inlet of the de-heavy distillation tower 3. The second heat exchange channel of the second heat exchanger 9 is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier 14, which is connected to the third channel of the fourth heat exchanger 2 through a buffer tank 16, and the third channel outlet of the fourth heat exchanger 2 is connected to the second heat exchange channel of the second heat exchanger 9; the second heat exchange channel outlet of the second heat exchanger 9 is connected to the inlet of the booster liquefier 14. A throttle valve 15 is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger 10.

[0061] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0062] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section 17 enters the first compressor 1 for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger 2 for heat exchange, and enters the de-heavy distillation tower 3 for distillation after heat exchange; the pressure of the tail gas after entering the first compressor 1 is: 9 bar, and the temperature after passing through the first channel of the fourth heat exchanger 2 is 16°C;

[0063] Step 2: the tail gas enters the de-heavy distillation tower 3 and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger 4 from the gas phase outlet at the top of the de-heavy distillation tower 3; the heavy components removed by the de-heavy distillation tower 3 mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower 3 is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0064] Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger 4 is 30°C. The gas phase at a temperature of 30°C passes through the booster 5 to increase the pressure of the raw gas to 27 bar and then enters the fine desulfurization tower 6 for desulfurization, reducing the sulfur content in the gas phase to below 0.1ppm;

[0065] Step 4: the gas phase after desulfurization through the refined desulfurization tower 6 enters the first heat exchange channel of the water cooler 7 for heat exchange, enters the second heat exchange channel of the first heat exchanger 4 for further heat exchange, and enters the light desulfurization distillation tower 8 for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler 7 is 43°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger 4 is -18°C;

[0066] Step 5: The raw gas entering the de-lightening distillation tower 8 undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower 8, and the carbon dioxide in the raw gas is continuously condensed and liquefied, enriched at the bottom of the tower, and enters the carbon dioxide storage tank 11 from the liquid phase outlet of the de-lightening distillation tower 8.

[0067] Furthermore, in the step 5, a part of the liquid phase at the bottom of the light removal distillation tower 8 enters the carbon dioxide storage tank 11 through a tee, and the other part is reduced in pressure to 9 Bar through a throttle valve 15 and then enters the second heat exchange channel of the third heat exchanger 10 as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger 10. After the heat exchange, it enters the second channel of the fourth heat exchanger 2 for heat exchange again, and after the heat exchange again, it is compressed by the second compressor 12 and enters the heavy removal distillation tower 3 for the production of carbon dioxide in the system.

[0068] Furthermore, in the step 5, the gas phase at the top of the light removal distillation tower 8 enters the first heat exchange channel of the second heat exchanger 9, and part of the gas phase is condensed and enters the heavy removal distillation tower 3 and the light removal distillation tower 8 as reflux liquid respectively; the remaining gas phase in the first heat exchange channel of the second heat exchanger 9 enters the first heat exchange channel of the third heat exchanger 10 for further condensation and liquefaction, and the condensed and liquefied liquid phase enters the heavy removal distillation tower 3 as reflux liquid, and the unliquefied gas phase in the first heat exchange channel of the third heat exchanger 10 enters the exhaust gas treatment device 13; the bottom liquid of the heavy removal distillation tower 3 in the step 2 also enters the exhaust gas treatment device 13 for treatment.

[0069] Example 4

[0070] A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section 17, wherein the tail gas pipeline of the low-temperature methanol washing section 17 is connected to the first inlet of a heavy-removal distillation tower 3 through a first compressor 1 and a first channel of a fourth heat exchanger 2, the gas phase outlet of the heavy-removal distillation tower 3 is connected to the inlet of a refined desulfurization tower 6 through a first heat exchange channel of a first heat exchanger 4 and a booster 5, the gas phase outlet of the refined desulfurization tower 6 is connected to the inlet of a light-removal distillation tower 8 through a first heat exchange channel of a water cooler 7 and a second heat exchange channel of the first heat exchanger 4, and the liquid phase outlet of the light-removal distillation tower 8 is connected to a carbon dioxide storage tank 11. The gas phase outlet of the de-light distillation tower 8 is connected to the first heat exchange channel of the second heat exchanger 9, and the liquid phase outlet of the first heat exchange channel of the second heat exchanger 9 is respectively connected to the reflux ports of the de-heavy distillation tower 3 and the de-light distillation tower 8. The gas phase outlet of the first heat exchange channel of the second heat exchanger 9 is connected to the first heat exchange channel of the third heat exchanger 10, and the liquid phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the reflux port of the de-heavy distillation tower 3. The gas phase outlet of the first heat exchange channel of the third heat exchanger 10 is connected to the tail gas treatment device 13. The liquid phase outlet of the de-heavy distillation tower 3 is connected to the tail gas treatment device 13. A tee is arranged between the liquid phase outlet of the de-light distillation tower 8 and the carbon dioxide storage tank 11, and the third end of the tee is connected to the second heat exchange channel of the third heat exchanger 10. The outlet of the second heat exchange channel of the third heat exchanger 10 is connected to the second compressor 12 through the second channel of the fourth heat exchanger 2, and the outlet of the second compressor 12 is connected to the second inlet of the de-heavy distillation tower 3. The second heat exchange channel of the second heat exchanger 9 is connected to the refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier 14, which is connected to the third channel of the fourth heat exchanger 2 through a buffer tank 16, and the third channel outlet of the fourth heat exchanger 2 is connected to the second heat exchange channel of the second heat exchanger 9; the second heat exchange channel outlet of the second heat exchanger 9 is connected to the inlet of the booster liquefier 14. A throttle valve 15 is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger 10.

[0071] The present invention also provides a process for removing high sulfur content in carbon dioxide tail gas, the process comprising the following steps:

[0072] Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section 17 enters the first compressor 1 for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger 2 for heat exchange, and enters the de-weighting distillation tower 3 for distillation after heat exchange; the pressure of the tail gas after entering the first compressor 1 is: 10 bar, and the temperature after passing through the first channel of the fourth heat exchanger 2 is 16°C;

[0073] Step 2: the tail gas enters the de-heavy distillation tower 3 and undergoes mass transfer and heat exchange with the reflux liquid from the top of the tower for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger 4 from the gas phase outlet at the top of the de-heavy distillation tower 3; the heavy components removed by the de-heavy distillation tower 3 mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower 3 is carbon dioxide, in which the sulfur content is reduced to below 20 ppm, and the main component is hydrogen sulfide;

[0074] Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger 4 is 35°C. The gas phase at a temperature of 35°C passes through the booster 5 to increase the pressure of the raw gas to 26 bar and then enters the fine desulfurization tower 6 for desulfurization, reducing the sulfur content in the gas phase to below 0.1ppm;

[0075] Step 4: the gas phase after desulfurization through the fine desulfurization tower 6 enters the first heat exchange channel of the water cooler 7 for heat exchange, enters the second heat exchange channel of the first heat exchanger 4 for further heat exchange, and enters the light desulfurization distillation tower 8 for distillation after further heat exchange; the gas phase temperature through the first heat exchange channel of the water cooler 7 is 44°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger 4 is -20°C;

[0076] Step 5: The raw gas entering the de-lightening distillation tower 8 undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower 8, and the carbon dioxide in the raw gas is continuously condensed and liquefied, enriched at the bottom of the tower, and enters the carbon dioxide storage tank 11 from the liquid phase outlet of the de-lightening distillation tower 8.

[0077] Furthermore, in the step 5, a part of the liquid phase at the bottom of the light removal distillation tower 8 enters the carbon dioxide storage tank 11 through a tee, and the other part is reduced in pressure to 7 Bar through a throttle valve 15 and then enters the second heat exchange channel of the third heat exchanger 10 as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger 10. After the heat exchange, it enters the second channel of the fourth heat exchanger 2 for heat exchange again, and after the heat exchange again, it is compressed by the second compressor 12 and enters the heavy removal distillation tower 3 for the production of carbon dioxide in the system. In the step 5, the gas phase at the top of the light removal distillation tower 8 enters the first heat exchange channel of the second heat exchanger 9, and part of the gas phase is condensed and enters the heavy removal distillation tower 3 and the light removal distillation tower 8 as reflux liquid respectively; the remaining gas phase in the first heat exchange channel of the second heat exchanger 9 enters the first heat exchange channel of the third heat exchanger 10 for further condensation and liquefaction, and the condensed and liquefied liquid phase enters the heavy removal distillation tower 3 as reflux liquid, and the unliquefied gas phase in the first heat exchange channel of the third heat exchanger 10 enters the exhaust gas treatment device 13; the bottom liquid of the heavy removal distillation tower 3 in the step 2 also enters the exhaust gas treatment device 13 for treatment. The refrigerant in the second heat exchange channel of the second heat exchanger 9 provides coldness for the first heat exchange channel of the second heat exchanger 9 and then enters the boost liquefier 14. After being pressurized by the buffer tank 16, it enters the third channel of the fourth heat exchanger 2 for heat exchange. The refrigerant after heat exchange enters the second heat exchange channel of the second heat exchanger 9 to form a cycle. The refrigerant is R717, R134a, R507; the refrigeration temperature of the refrigerant is -18 to -42°C.

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for removing high sulfur content in carbon dioxide tail gas, comprising a low-temperature methanol washing section (17), characterized in that: The tail gas pipeline of the low-temperature methanol washing section (17) is connected to the first inlet of the de-heavy distillation tower (3) through the first compressor (1) and the first channel of the fourth heat exchanger (2); the gas phase outlet of the de-heavy distillation tower (3) is connected to the inlet of the fine desulfurization tower (6) through the first heat exchange channel of the first heat exchanger (4) and the booster (5); the gas phase outlet of the fine desulfurization tower (6) is connected to the inlet of the de-light distillation tower (8) through the first heat exchange channel of the water cooler (7) and the second heat exchange channel of the first heat exchanger (4); and the liquid phase outlet of the de-light distillation tower (8) is connected to the carbon dioxide storage tank (11).

2. The device for removing high sulfur content in carbon dioxide tail gas according to claim 1, characterized in that: The gas phase outlet of the light-removal distillation tower (8) is connected to the first heat exchange channel of the second heat exchanger (9), the liquid phase outlet of the first heat exchange channel of the second heat exchanger (9) is connected to the reflux ports of the heavy-removal distillation tower (3) and the light-removal distillation tower (8) respectively, the gas phase outlet of the first heat exchange channel of the second heat exchanger (9) is connected to the first heat exchange channel of the third heat exchanger (10), the liquid phase outlet of the first heat exchange channel of the third heat exchanger (10) is connected to the reflux port of the heavy-removal distillation tower (3), and the gas phase outlet of the first heat exchange channel of the third heat exchanger (10) is connected to the tail gas treatment device (13).

3. A device for removing high sulfur content in carbon dioxide tail gas according to claim 2, characterized in that: The liquid phase outlet of the de-heavy distillation tower (3) is connected to the tail gas treatment device (13).

4. A device for removing high sulfur content in carbon dioxide tail gas according to claim 2, characterized in that: A tee is provided between the liquid phase outlet of the light-removal distillation tower (8) and the carbon dioxide storage tank (11); the third end of the tee is connected to the second heat exchange channel of the third heat exchanger (10); the outlet of the second heat exchange channel of the third heat exchanger (10) is connected to the second compressor (12) via the second channel of the fourth heat exchanger (2); and the outlet of the second compressor (12) is connected to the second inlet of the heavy-removal distillation tower (3).

5. The device for removing high sulfur content in carbon dioxide tail gas according to claim 2, characterized in that: The second heat exchange channel of the second heat exchanger (9) is connected to a refrigerant circulation unit, and the refrigerant circulation unit includes a booster liquefier (14). The booster liquefier (14) is connected to the third channel of the fourth heat exchanger (2) through a buffer tank (16), and the third channel outlet of the fourth heat exchanger (2) is connected to the second heat exchange channel of the second heat exchanger (9); the second heat exchange channel outlet of the second heat exchanger (9) is connected to the inlet of the booster liquefier (14).

6. The device for removing high sulfur content in carbon dioxide tail gas according to claim 2, characterized in that: A throttle valve (15) is provided between the third end of the tee and the second heat exchange channel of the third heat exchanger (10).

7. A process for removing high sulfur content in carbon dioxide tail gas, characterized in that: The process comprises the following steps: Step 1: The tail gas in the tail gas pipeline of the low-temperature methanol washing section (17) enters the first compressor (1) for compression, and the compressed tail gas enters the first channel of the fourth heat exchanger (2) for heat exchange, and after heat exchange, enters the de-weighting distillation tower (3) for distillation; the pressure of the tail gas after entering the first compressor (1) is 6 to 12 bar, and the temperature of the tail gas after passing through the first channel of the fourth heat exchanger (2) is 9 to 20°C; Step 2: the tail gas enters a de-heavy distillation tower (3) and undergoes mass transfer and heat exchange with the reflux liquid from the tower top for distillation, and the light components and the gas phase evaporated by the reflux liquid after heat transfer enter the first heat exchange channel of the first heat exchanger (4) from the gas phase outlet at the top of the de-heavy distillation tower (3); the heavy components removed by the de-heavy distillation tower (3) mainly include alcohol, water, hydrogen sulfide, and carbonyl sulfide impurities in the feed gas; the gas phase at the top of the de-heavy distillation tower (3) is carbon dioxide, the sulfur content of which is reduced to below 20 ppm, and the main component is hydrogen sulfide; Step 3: The temperature of the gas phase after heat exchange in the first heat exchange channel of the first heat exchanger (4) is 20-40°C. The gas phase with a temperature of 20-40°C passes through a booster (5) to increase the pressure of the raw gas to 22-32 bar, and then enters a fine desulfurization tower (6) for desulfurization, reducing the sulfur content in the gas phase to below 0.1 ppm; Step 4: the gas phase after desulfurization through the fine desulfurization tower (6) enters the first heat exchange channel of the water cooler (7) for heat exchange, enters the second heat exchange channel of the first heat exchanger (4) for further heat exchange, and enters the light desulfurization distillation tower (8) for distillation after further heat exchange; the gas phase temperature after passing through the first heat exchange channel of the water cooler (7) is 40 to 45°C, and the gas phase temperature after further heat exchange through the second heat exchange channel of the first heat exchanger (4) is -22 to -14°C; Step 5: The raw gas entering the de-lightening distillation tower (8) undergoes mass transfer and heat exchange with the reflux liquid at the top of the de-lightening distillation tower (8), and the carbon dioxide in the raw gas is continuously condensed and liquefied, and is enriched at the bottom of the tower, and enters the carbon dioxide storage tank (11) from the liquid phase outlet of the de-lightening distillation tower (8).

8. A process for removing high sulfur content in carbon dioxide tail gas according to claim 7, characterized in that: In the step 5, a portion of the liquid phase at the bottom of the light removal distillation tower (8) enters the carbon dioxide storage tank (11) through a tee, and the other portion is reduced in pressure to 6 to 9 Bar through a throttle valve (15) and then enters the second heat exchange channel of the third heat exchanger (10) as a cold source to exchange heat with the material from the first heat exchange channel of the third heat exchanger (10). After the heat exchange, the liquid phase enters the second channel of the fourth heat exchanger (2) for another heat exchange, and after the second heat exchange, it is compressed by the second compressor (12) and then enters the heavy removal distillation tower (3) for the production of carbon dioxide in the system.

9. A process for removing high sulfur content in carbon dioxide tail gas according to claim 8, characterized in that: In the step 5, the gas phase at the top of the light removal distillation tower (8) enters the first heat exchange channel of the second heat exchanger (9), and part of the gas phase is condensed and enters the heavy removal distillation tower (3) and the light removal distillation tower (8) as reflux liquid respectively; the remaining gas phase in the first heat exchange channel of the second heat exchanger (9) enters the first heat exchange channel of the third heat exchanger (10) for further condensation and liquefaction, and the condensed and liquefied liquid phase enters the heavy removal distillation tower (3) as reflux liquid, and the unliquefied gas phase in the first heat exchange channel of the third heat exchanger (10) enters the tail gas treatment device (13); the bottom liquid of the heavy removal distillation tower (3) in the step 2 also enters the tail gas treatment device (13) for treatment.

10. A process for removing high sulfur content in carbon dioxide tail gas according to claim 9, characterized in that: The refrigerant in the second heat exchange channel of the second heat exchanger (9) provides cooling capacity for the first heat exchange channel of the second heat exchanger (9) and then enters the booster liquefier (14). After being pressurized by the buffer tank (16), the refrigerant enters the third channel of the fourth heat exchanger (2) for heat exchange. After the heat exchange, the refrigerant enters the second heat exchange channel of the second heat exchanger (9) to form a cycle. The refrigerant is R717, R134a, or R507. The refrigeration temperature of the refrigerant is -18 to -42°C.

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