Waste gas recycling system of coal hydrogen production device

Abstract

The utility model relates to a waste gas recycling system of a coal hydrogen production device, which comprises a water scrubber, a liquid separation tank, a desulfurizing tower, a compressor and a rectifying unit, the top of the water scrubber is communicated with the liquid separation tank through a first gas pipe, the top of the liquid separation tank is communicated with the desulfurizing tower through a second gas pipe, and the top of the desulfurizing tower is communicated with the compressor through a third gas pipe. The rectifying unit comprises a rectifying tower, a condenser and a gas-liquid separator, the compressor is communicated with the rectifying tower through a fourth gas pipe, and the rectifying tower, the condenser and the gas-liquid separator are sequentially and circularly communicated through circulating gas pipes; according to the utility model, food-grade liquid carbon dioxide products can be extracted from the rectifying tower, so that the utilization rate of resources is improved, low-carbon emission is realized, and waste of carbon dioxide resources is avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of waste gas treatment equipment, specifically to a waste gas recovery and utilization system for a coal-to-hydrogen device. Background Technology

[0002] A coal-to-hydrogen plant is an industrial equipment system that converts coal into hydrogen through chemical or thermochemical processes. Coal-to-hydrogen uses coal as a reducing agent and steam as an oxidizing agent to convert carbon into syngas, primarily carbon monoxide and hydrogen, at high temperatures. After purification, carbon monoxide conversion, and further refinement, hydrogen and syngas are produced. However, during the production process, coal-to-hydrogen plants emit waste gas containing carbon dioxide, resulting in a waste of carbon dioxide resources. Utility Model Content

[0003] The purpose of this invention is to design a waste gas recovery and utilization system for a coal-to-hydrogen plant, which can solve the technical problem mentioned in the background art that the coal-to-hydrogen plant will emit waste gas containing carbon dioxide during the production process, resulting in the waste of carbon dioxide resources.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A waste gas recovery and utilization system for a coal-to-hydrogen plant includes a water washing tower, a liquid separator, a desulfurization tower, a compressor, and a distillation unit. The top of the water washing tower is connected to the liquid separator via a first gas pipe, the top of the liquid separator is connected to the desulfurization tower via a second gas pipe, and the top of the desulfurization tower is connected to the compressor via a third gas pipe. The distillation unit includes a distillation tower, a condenser, and a gas-liquid separator. The compressor is connected to the distillation tower via a fourth gas pipe. The distillation tower, the condenser, and the gas-liquid separator are all sequentially connected via a circulating gas pipe.

[0006] Furthermore, it also includes a sewage tank, and the bottoms of the water washing tower, the liquid separator, and the desulfurization tower are all connected to the sewage tank via sewage pipes.

[0007] Furthermore, it also includes an exhaust gas treatment unit, and the exhaust port of the gas-liquid separator is connected to the exhaust gas treatment unit through a fifth gas pipe.

[0008] Furthermore, the exhaust gas treatment unit includes a heat exchanger and a catalytic oxidation reactor. The first air inlet of the heat exchanger is connected to the fifth gas pipe, the first exhaust port of the heat exchanger is connected to the air inlet of the catalytic oxidation reactor through a first heat exchange pipe, the exhaust port of the catalytic oxidation reactor is connected to the second air inlet of the heat exchanger through a second heat exchange pipe, and the second exhaust port of the heat exchanger is connected to a high-altitude emission pipe.

[0009] Furthermore, an electric heater is provided between the heat exchanger and the catalytic oxidation reactor. The inlet of the electric heater is connected to the first heat exchange tube, and the outlet of the electric heater is connected to the inlet of the catalytic oxidation reactor through a heating pipe.

[0010] The beneficial effects of this utility model are as follows:

[0011] The generated waste gas is discharged into a water washing tower for washing to remove impurities and sulfur-containing components. The gas containing carbon dioxide at the top of the water washing tower is sent to a separating tank through a first gas pipe for separation. The gas containing carbon dioxide at the top of the separating tank is sent to a desulfurization tower through a second gas pipe to remove trace amounts of sulfur-containing components. The relatively pure carbon dioxide at the top of the desulfurization tower is sent to a compressor through a third gas pipe for compression. The compressed relatively pure carbon dioxide enters a distillation tower to remove heavy components with higher boiling points than carbon dioxide, such as methanol. The gas after the heavy components are removed enters a condenser for cooling. The resulting gas-liquid mixture enters a gas-liquid separator for gas-liquid separation. The separated liquid carbon dioxide returns to the distillation tower. Finally, food-grade liquid carbon dioxide is extracted from the distillation tower, improving resource utilization, achieving low carbon emissions, and avoiding waste of carbon dioxide resources. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart illustrating the workflow of this utility model.

[0014] Figure 2 This is a flowchart illustrating the process of the distillation unit in this invention.

[0015] Figure 3 This is a flowchart of the exhaust gas treatment unit in this utility model.

[0016] The names of the components shown in the diagram are as follows:

[0017] 1. Water washing tower; 2. Separating tank; 3. Desulfurization tower; 4. Compressor; 5. Distillation unit; 51. Distillation tower; 52. Condenser; 53. Gas-liquid separator; 6. Wastewater tank; 7. Tail gas treatment unit; 71. Heat exchanger; 72. Catalytic oxidation reactor; 73. Electric heater; 8. First gas pipe; 9. Second gas pipe; 10. Third gas pipe; 11. Fourth gas pipe; 12. Sewage pipe; 13. Fifth gas pipe; 14. First heat exchanger tube; 15. Second heat exchanger tube; 16. High-altitude exhaust pipe; 17. Heating pipe; 18. Circulating gas pipe. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0019] like Figure 1-3 As shown, a waste gas recovery and utilization system for a coal-to-hydrogen plant includes a water washing tower 1, a separating tank 2, a desulfurization tower 3, a compressor 4, a distillation unit 5, a wastewater tank 6, and a tail gas treatment unit 7. The top of the water washing tower 1 is connected to the separating tank 2 via a first gas pipe 8. The top of the separating tank 2 is connected to the desulfurization tower 3 via a second gas pipe 9. The top of the desulfurization tower 3 is connected to the compressor 4 via a third gas pipe 10. The coal-to-hydrogen plant is connected to the water washing tower 1 via an exhaust pipe. The waste gas generated during the production process of the coal-to-hydrogen plant is discharged into the water washing tower 1 through the exhaust pipe for water washing treatment, in which impurities and sulfur-containing components are removed. The gas containing carbon dioxide at the top of the water washing tower 1 is sent to the liquid separator 2 through the first gas pipe 8 for liquid separation. Then, the gas containing carbon dioxide at the top of the liquid separator 2 is sent to the desulfurization tower 3 through the second gas pipe 9. Trace amounts of sulfur-containing components are removed in the desulfurization tower 3. The relatively pure carbon dioxide at the top of the desulfurization tower 3 is sent to the compressor 4 through the third gas pipe 10 for compression. The bottoms of the water washing tower 1, the liquid separator 2, and the desulfurization tower 3 are all connected to the sewage tank 6 through the sewage discharge pipe 12. The sulfur-containing wastewater discharged from the water washing tower 1, the liquid separator 2, and the desulfurization tower 3 is collected in the sewage tank 6 and then neutralized.

[0020] The distillation unit 5 includes a distillation column 51, a condenser 52, and a gas-liquid separator 53. The compressor 4 is connected to the distillation column 51 through a fourth gas pipe 11. The distillation column 51, the condenser 52, and the gas-liquid separator 53 are all sequentially connected through a circulating gas pipe 18. The carbon dioxide compressed by the compressor 4 is sent to the distillation column 51 through the fourth gas pipe 11. In the distillation column 51, heavy components such as methanol with higher boiling points than carbon dioxide are removed. The gas after the heavy components are removed enters the condenser 52 through the circulating gas pipe 18 for cooling. The resulting gas-liquid mixture enters the gas-liquid separator through the circulating gas pipe 18 for gas-liquid separation. The separated liquid carbon dioxide is returned to the distillation column 51 through the circulating gas pipe 18. Food-grade liquid carbon dioxide products can be obtained in the distillation column 51, improving resource utilization, achieving low carbon emissions, and avoiding waste of carbon dioxide resources.

[0021] The exhaust gas treatment unit 7 includes a heat exchanger 71, a catalytic oxidation reactor 72, and an electric heater 73. The exhaust port of the gas-liquid separator 53 is connected to the first inlet of the heat exchanger 71 through a fifth gas pipe 13. The first exhaust port of the heat exchanger 71 is connected to the inlet of the electric heater 73 through a first heat exchange pipe 14. The exhaust port of the electric heater 73 is connected to the inlet of the catalytic oxidation reactor 72 through a heating pipe 17. The exhaust port of the catalytic oxidation reactor 72 is connected to the second inlet of the heat exchanger 71 through a second heat exchange pipe 15. The second exhaust port of the heat exchanger 71 is connected to a high-altitude exhaust pipe 16. The exhaust gas separated by separator 53 enters heat exchanger 71 through fifth gas pipe 13. The low-temperature exhaust gas exchanges heat with the high-temperature qualified gas to raise the temperature of the exhaust gas. The heated exhaust gas then enters electric heater 73 through first heat exchange pipe 14 for further heating. The heated exhaust gas then enters catalytic oxidation reactor 72 through heating pipe 17 for catalytic oxidation treatment. The treated qualified gas then enters heat exchanger 71 through second heat exchange pipe 15. The high-temperature qualified gas exchanges heat with the low-temperature exhaust gas to lower the temperature of the qualified gas. Finally, the cooled qualified gas is discharged through high-altitude exhaust pipe 16.

[0022] Working principle:

[0023] like Figure 1-3As shown, when the waste gas recovery and utilization system is in operation, the waste gas generated during the production process of the coal-to-hydrogen unit is discharged into the water washing tower 1 through the exhaust pipe for water washing treatment. Impurities and sulfur-containing components are removed in the water washing tower 1. The gas containing carbon dioxide at the top of the water washing tower 1 is sent to the separating tank 2 through the first gas pipe 8 for separation treatment. Then, the gas containing carbon dioxide at the top of the separating tank 2 is sent to the desulfurization tower 3 through the second gas pipe 9. Trace amounts of sulfur-containing components are removed in the desulfurization tower 3. The relatively pure carbon dioxide at the top of the desulfurization tower 3 is sent to the third gas pipe 10... The compressor 4 compresses the carbon dioxide, and the compressed carbon dioxide is sent to the distillation column 51 through the fourth gas pipe 11. In the distillation column 51, heavy components such as methanol with a boiling point higher than carbon dioxide are removed. The gas after the heavy components are removed enters the condenser 52 through the circulating gas pipe 18 for cooling. The resulting gas-liquid mixture enters the gas-liquid separator through the circulating gas pipe 18 for gas-liquid separation. The separated liquid carbon dioxide will re-enter the distillation column 51 through the circulating gas pipe 18. Food-grade liquid carbon dioxide product can be obtained in the distillation column 51.

[0024] The sulfur-containing wastewater discharged from the water washing tower 1, the separating tank 2, and the desulfurization tower 3 will be collected into the wastewater pool 6. The wastewater pool 6 will then undergo neutralization treatment. The tail gas separated by the gas-liquid separator 53 will enter the heat exchanger 71 through the fifth gas pipe 13. The low-temperature tail gas will exchange heat with the high-temperature qualified gas to raise the temperature of the tail gas. The heated tail gas will then enter the electric heater 73 through the first heat exchange pipe 14 for further heating. The further heated tail gas will then enter the catalytic oxidation reactor 72 through the heating pipe 17 for catalytic oxidation treatment. The treated qualified gas will then enter the heat exchanger 71 through the second heat exchange pipe 15. The high-temperature qualified gas will exchange heat with the low-temperature tail gas to lower the temperature of the qualified gas. Finally, the cooled qualified gas will be discharged through the high-altitude exhaust pipe 16.

[0025] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A coal-to-hydrogen plant off-gas recycling system, characterized by, The system includes a water washing tower (1), a liquid separator (2), a desulfurization tower (3), a compressor (4), and a distillation unit (5). The top of the water washing tower (1) is connected to the liquid separator (2) through a first gas pipe (8). The top of the liquid separator (2) is connected to the desulfurization tower (3) through a second gas pipe (9). The top of the desulfurization tower (3) is connected to the compressor (4) through a third gas pipe (10). The distillation unit (5) includes a distillation tower (51), a condenser (52), and a gas-liquid separator (53). The compressor (4) is connected to the distillation tower (51) through a fourth gas pipe (11). The distillation tower (51), the condenser (52), and the gas-liquid separator (53) are all connected in a circulating manner through a circulating gas pipe (18).

2. The waste gas recovery and utilization system for a coal-to-hydrogen plant according to claim 1, characterized in that, It also includes a sewage tank (6), and the bottoms of the water washing tower (1), the liquid separator (2) and the desulfurization tower (3) are all connected to the sewage tank (6) through a sewage pipe (12).

3. The waste gas recovery and utilization system for a coal-to-hydrogen plant according to claim 1, characterized in that, It also includes an exhaust gas treatment unit (7), and the exhaust port of the gas-liquid separator (53) is connected to the exhaust gas treatment unit (7) through the fifth gas pipe (13).

4. The waste gas recovery and utilization system for a coal-to-hydrogen plant according to claim 3, characterized in that, The exhaust gas treatment unit (7) includes a heat exchanger (71) and a catalytic oxidation reactor (72). The first air inlet of the heat exchanger (71) is connected to the fifth gas pipe (13). The first exhaust port of the heat exchanger (71) is connected to the air inlet of the catalytic oxidation reactor (72) through the first heat exchange pipe (14). The exhaust port of the catalytic oxidation reactor (72) is connected to the second air inlet of the heat exchanger (71) through the second heat exchange pipe (15). The second exhaust port of the heat exchanger (71) is connected to a high-altitude exhaust pipe (16).

5. The waste gas recovery and utilization system for a coal-to-hydrogen plant according to claim 4, characterized in that, An electric heater (73) is provided between the heat exchanger (71) and the catalytic oxidation reactor (72). The inlet of the electric heater (73) is connected to the first heat exchange tube (14), and the outlet of the electric heater (73) is connected to the inlet of the catalytic oxidation reactor (72) through the heating pipe (17).

Images