Coal gas preheating device capable of efficiently recycling transformation waste heat

Abstract

The utility model discloses a coal gas preheating device capable of efficiently recycling transformation waste heat, which comprises a shell pass, a tube pass, a tube plate and a U-shaped tube, the shell pass is of a vertical structure, a partition plate is arranged in the tube pass, a coal gas inlet and a coal gas outlet are respectively arranged on a shell of the tube pass on two sides of the partition plate, and the U-shaped tube comprises an outer tube and an inner tube which are concentrically arranged. The two ends of the inner pipe are plugged through plugs, a plurality of positioning blocks are arranged between the outer pipe and the inner pipe, a shift gas inlet is formed in the upper portion of the shell side shell, a gas inlet pipe and a gas outlet pipe are arranged at the two ends of the outer pipe respectively and communicate with the inner pipe, and the gas inlet pipe is located at the bottom in the shell side. The gas outlet pipe is located in the gas collecting cavity, and a converted gas outlet communicated with the gas collecting cavity is formed in one side of the pipe plate. In conclusion, the heat exchanger has the advantages of high energy utilization rate, energy conservation, consumption reduction and high heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of gas preheating technology, specifically to a gas preheating device that efficiently recovers and utilizes waste heat from conversion. Background Technology

[0002] In coal-to-hydrogen production, the crude syngas from upstream coal gasification units typically contains a high amount of carbon monoxide, sometimes exceeding 70%. Therefore, a shift catalytic reaction is needed to convert carbon monoxide into carbon dioxide and hydrogen, resulting in hydrogen-rich process gas, known as shift gas. Shift gas is a key intermediate product in coal chemical engineering that adjusts the gas composition through a water-gas shift reaction. After downstream decarbonization, desulfurization, or separation and purification, high-purity hydrogen is obtained.

[0003] Water-gas shift reaction is a catalytic reaction. To ensure catalyst activity, reaction efficiency, and system stability, and to achieve a high carbon monoxide conversion rate, the gas needs to be preheated in the water-gas shift process, consuming a large amount of energy and increasing the company's operating costs. Furthermore, the carbon monoxide-water shift reaction is a strongly exothermic reaction, with a hot spot temperature reaching as high as 450℃. Heat recovery is achieved by setting up multiple heat exchangers for producing low-pressure steam, waste heat boiler feedwater, and heating demineralized water, but this method suffers from low heat exchange efficiency, low energy utilization, and poor recovery effects. Moreover, most of the steam produced is of low grade and often fails to meet usage requirements, resulting in direct venting and significant energy waste. Therefore, developing a highly efficient gas preheating device that recovers and utilizes waste heat from the water-gas shift reaction is objectively necessary, as it offers high energy utilization, energy saving, and high heat exchange efficiency. Utility Model Content

[0004] The purpose of this invention is to provide a gas preheating device that has high energy utilization, energy saving and consumption reduction, and high heat exchange efficiency for the efficient recovery and utilization of waste heat.

[0005] The purpose of this utility model is achieved as follows: it includes a shell side, a tube side, a tube sheet, and a U-shaped tube with a vertical structure. A baffle is provided inside the tube side. Gas inlet and gas outlet are respectively provided on the tube side shell on both sides of the baffle. The U-shaped tube includes an outer tube and an inner tube arranged concentrically. The two ends of the inner tube are sealed by plugs. Several positioning blocks are provided between the outer tube and the inner tube. A gas inlet is provided at the upper part of the shell side shell. An inlet pipe and an outlet pipe are respectively provided at both ends of the outer tube. Both the inlet pipe and the outlet pipe are connected to the inner tube. The inlet pipe is located at the bottom of the shell side. A closed gas collection chamber is provided inside the tube sheet. The outlet pipe is located inside the gas collection chamber. A gas outlet communicating with the gas collection chamber is provided on one side of the tube sheet.

[0006] Furthermore, the plug is connected to the end of the inner tube by a thread.

[0007] Furthermore, a spiral guide plate is installed in the annular space between the inner and outer tubes.

[0008] Furthermore, several heat-conducting ring plates are installed on the outer wall of the outer tube.

[0009] Furthermore, the two ports of the outer pipe are the gas inlet and the gas outlet, respectively. The inlet pipe is located at the gas outlet of the outer pipe, and the outlet pipe is located at the gas inlet of the outer pipe.

[0010] Furthermore, a high-temperature resistant ring gasket is installed between the tube sheet above the gas collection cavity and the outer tube.

[0011] This invention is used to recover and utilize the waste heat of shift gas to preheat coal gas. During operation, coal gas is introduced into the coal gas inlet on the tube side. Due to the end blockage of the inner tube, the coal gas can only enter the annular space between the inner and outer tubes, and then flow in this annular space. Finally, it flows into the tube side from the other end of the outer tube and is discharged from the coal gas outlet. At the same time, shift gas is introduced into the shell side from the shift gas inlet. The shift gas flows from top to bottom in the shell side, and then enters the inner tube through the inlet pipe. It flows in the inner tube and is discharged from the outlet pipe at the other end of the inner tube. The shift gas enters the gas collection chamber in the tube sheet and is finally discharged from the shift gas outlet. The above process is the flow of shift gas and coal gas in the coal gas preheating device. In this invention, the heat exchange tube is configured as a double-layer structure, consisting of an outer tube and an inner tube. During operation, the coal gas flows within the annular space between the outer and inner tubes. The shifted gas is located both outside the outer tube and inside the inner tube. This configuration ensures that both sides of the coal gas are filled with shifted gas, meaning that the shifted gas outside the outer tube and inside the inner tube simultaneously heat the coal gas from both sides. Compared to the existing single-layer structure of heat exchange tubes, this significantly increases the heat exchange area between the coal gas and the shifted gas. Existing structures only utilize the outer wall area of ​​the outer tube for heat exchange, while this invention also increases the outer wall area of ​​the inner tube, thus greatly increasing the heat exchange area. Improving the heat exchange efficiency between coal gas and shift gas allows the coal gas to fully absorb the waste heat from the shift gas, thus increasing energy utilization. Secondly, the heat source for preheating the coal gas in this invention comes from the shift gas after the shift reaction. The shift gas contains a large amount of heat; utilizing its waste heat to preheat the coal gas reduces energy consumption for preheating, lowering operating costs for enterprises. Simultaneously, this method efficiently recovers and utilizes the heat from the shift gas, avoiding the waste problem caused by the traditional method of using shift gas waste heat to produce low-grade, low-pressure steam, which is then directly discharged because it cannot meet usage requirements. Therefore, this invention reduces energy waste. In summary, this invention has the advantages of high energy utilization, energy saving and consumption reduction, and high heat exchange efficiency. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Figure 2 for Figure 1 A magnified structural diagram of node A in the middle;

[0014] In the diagram: 1-shell side, 2-tube side, 3-tube sheet, 4-gas inlet, 5-gas outlet, 6-outer tube, 7-inner tube, 8-plug, 9-positioning block, 10-converter gas inlet, 11-inlet pipe, 12-outlet pipe, 13-gas collection chamber, 14-converter gas outlet, 15-spiral guide plate, 16-heat-conducting ring plate, 17-high temperature resistant ring gasket. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0016] like Figures 1-2 As shown, this utility model includes a vertical shell side 1, a tube side 2, a tube sheet 3, and a U-shaped tube. That is, this utility model is a vertical U-shaped tube heat exchange structure. The U-shaped tube is located inside the shell side 1, and its ends are welded and sealed firmly to the tube sheet 3. A baffle is installed inside the tube side 2, dividing the space inside the shell side 2 into two parts, i.e., the tube side has two passes. In actual production, the number of passes in the tube side 2 can be reasonably set as needed to improve the heat exchange effect between the changeover gas and the coal gas. A coal gas inlet 4 and a coal gas outlet 5 are respectively provided on the shell side of the tube side 2 on both sides of the baffle. The tube system includes an outer tube 6 and an inner tube 7 arranged concentrically. Both ends of the inner tube 7 are sealed with plugs 8. Several positioning blocks 9 are provided between the outer tube 6 and the inner tube 7. These positioning blocks 9 can be fixed to the outer tube 6 or placed on the inner tube 7 to fix the position of the inner tube 7, ensuring concentricity between the inner tube 7 and the outer tube 6. In actual installation, several groups of positioning blocks 9 can be arranged along the length of the heat exchange tube, with 2-3 blocks in each group and evenly distributed circumferentially. A gas inlet 10 is provided at the upper part of the shell side 1. An inlet pipe 11 and an outlet pipe 12 are respectively provided at both ends of the outer tube 6. Both the inlet pipe 11 and the outlet pipe 12 are connected to the inner pipe 7. The inlet pipe 11 is located at the bottom of the shell side 1. A closed gas collection chamber 13 is provided in the tube sheet 3. The outlet pipe 12 is located in the gas collection chamber 13. Both the outer pipe 6 and the inner pipe 7 are U-shaped structures. The inlet pipe 11 and the outlet pipe 12 are located at both ends of the U-shaped structure. When the change gas enters the inner pipe 7 through the inlet pipe 11, it can flow through the entire inner pipe 7 and finally be discharged from the outlet pipe 12 into the gas collection chamber 13. A change gas outlet 14 connected to the gas collection chamber 13 is provided on one side of the tube sheet 3.

[0017] This invention is used to recover and utilize the waste heat of shift gas to preheat coal gas. During operation, coal gas is introduced into the coal gas inlet 4 on the tube side 2. Due to the end blockage of the inner tube 7, the coal gas can only enter the annular space between the inner tube 7 and the outer tube 6, and then flow in this annular space. Finally, it flows into the tube side 2 from the other end of the outer tube 6 and is discharged from the coal gas outlet 5. At the same time, shift gas is introduced into the shell side 1 from the shift gas inlet 10. The shift gas flows from top to bottom in the shell side 1, and then enters the inner tube 7 through the inlet pipe 11. It flows in the inner tube 7 and is discharged from the outlet pipe 12 at the other end of the inner tube 7. The shift gas enters the gas collection chamber 13 in the tube sheet 3 and is finally discharged from the shift gas outlet 14. The above process is the flow of shift gas and coal gas in the coal gas preheating device.

[0018] In this invention, the heat exchange tube is configured as a double-layer structure, consisting of an outer tube 6 and an inner tube 7. During operation, the coal gas flows within the annular space between the outer tube 6 and the inner tube 7. The shifted gas is located both outside the outer tube 6 and inside the inner tube 7. This configuration ensures that both sides of the coal gas are filled with shifted gas, meaning that the shifted gas outside the outer tube 6 and the shifted gas inside the inner tube 7 simultaneously heat the coal gas from both sides. Compared to the existing single-layer structure of the heat exchange tube, this significantly increases the heat exchange area between the coal gas and the shifted gas. In the existing structure, only the area of ​​the outer wall of the outer tube 6 is used for heat exchange, while this invention also increases the area of ​​the outer wall of the inner tube 7. This significantly improves the heat exchange efficiency between the coal gas and the shifted gas, allowing the coal gas to fully absorb the waste heat from the shifted gas and improve energy utilization. Secondly, the heat source for preheating the coal gas in this invention comes from the shifted gas after the shift reaction. The shifted gas contains a large amount of heat. Utilizing its waste heat to preheat the coal gas can reduce the energy consumption for coal gas preheating and lower the operating costs of enterprises. At the same time, this method efficiently recovers and utilizes the heat in the shifted gas, avoiding the waste problem caused by using the waste heat of the shifted gas to produce low-grade, low-pressure steam in the traditional method, which is then directly discharged because it cannot meet the usage requirements. This thus reduces energy waste.

[0019] To facilitate the installation and removal of the plug 8, and to facilitate the discharge of impurities accumulated in the inner tube 7, the plug 8 is connected to the end of the inner tube 7 by a thread. When needed, the plug 8 can be removed, and the impurities in the inner tube 7 can be discharged under gravity. Impurities adhering to the inner wall of the inner tube 7 can also be cleaned.

[0020] A spiral guide plate 15 is installed in the annular space between the inner pipe 7 and the outer pipe 6. The spiral guide plate 15 forms a connected spiral flow channel in the annular space. The gas flows spirally in the spiral flow channel, which can extend the flow path of the gas and extend the heat exchange time, thereby improving the heat exchange efficiency.

[0021] Several heat-conducting ring plates 16 are provided on the outer wall of the outer tube 6. The heat-conducting ring plates 16 are installed on the outer tube 6, which can increase the heat exchange area between the change gas and the coal gas in the shell side 1, thereby improving the heat exchange efficiency of both.

[0022] The outer pipe 6 has two ports, namely the gas inlet and the gas outlet. The inlet pipe 11 is located at the gas outlet of the outer pipe 6, and the outlet pipe 12 is located at the gas inlet of the outer pipe 6. In this invention, the shift gas enters the upper part of the shell side 1 from the shift gas inlet 10, then flows downward, enters the inner pipe 7 from the inlet pipe 11, and finally enters the gas collection chamber 13 from the other end of the inner pipe 7. By setting the inlet pipe 11 at the gas outlet of the outer pipe 6, the gas and the shift gas in the inner pipe 7 can flow in opposite directions, increasing the temperature difference between them and improving the heat exchange efficiency.

[0023] A high-temperature resistant ring gasket 17 is provided between the tube sheet 3 and the outer tube 6 above the gas collection chamber 13. In actual use, due to processing errors or installation problems, there will be a certain gap between the tube sheet 3 and the outer tube 6. This gap connects the shell side 1 and the gas collection chamber 13. Some of the change gas in the shell side 1 will directly enter the gas collection chamber 13 through this gap instead of entering the inner tube 7, which will reduce the heat exchange efficiency between the change gas and the coal gas. In order to avoid this problem as much as possible, a high-temperature resistant ring gasket 17 is provided between the tube sheet 3 and the outer tube 6. In actual use, for ease of installation, the cross section of the high-temperature resistant ring gasket 17 can be set as a seven-shaped or concave shape. It is first clamped on the tube hole of the tube sheet 3 and then inserted into the heat exchange tube.

Claims

1. A high-efficiency gas preheating device for recovering and utilizing waste heat from conversion, comprising a shell side (1), a tube side (2), a tube sheet (3), and a U-shaped tube in a vertical structure, characterized in that: A baffle is provided inside the tube side (2). Gas inlet (4) and gas outlet (5) are respectively provided on the shell of the tube side (2) on both sides of the baffle. The U-shaped tube includes an outer tube (6) and an inner tube (7) arranged concentrically. The two ends of the inner tube (7) are sealed by plugs (8). Several positioning blocks (9) are provided between the outer tube (6) and the inner tube (7). A change gas inlet (10) is provided at the upper part of the shell side (1). An air inlet pipe (11) and an air outlet pipe (12) are respectively provided at both ends of the outer tube (6). The air inlet pipe (11) and the air outlet pipe (12) are both connected to the inner tube (7). The air inlet pipe (11) is located at the bottom of the shell side (1). A closed gas collection chamber (13) is provided inside the tube plate (3). The air outlet pipe (12) is located inside the gas collection chamber (13). A change gas outlet (14) connected to the gas collection chamber (13) is provided on one side of the tube plate (3).

2. The gas preheating device for efficient recovery and utilization of waste heat according to claim 1, characterized in that: The plug (8) is connected to the end of the inner tube (7) by a thread.

3. The gas preheating device for efficient recovery and utilization of waste heat according to claim 1, characterized in that: A spiral guide plate (15) is provided in the annular space between the inner tube (7) and the outer tube (6).

4. The gas preheating device for efficient recovery and utilization of waste heat according to claim 1, characterized in that: Several heat-conducting ring plates (16) are provided on the outer wall of the outer tube (6).

5. The gas preheating device for efficient recovery and utilization of waste heat according to claim 1, characterized in that: The two ports of the outer pipe (6) are the gas inlet and the gas outlet, respectively. The inlet pipe (11) is located at the gas outlet of the outer pipe (6), and the outlet pipe (12) is located at the gas inlet of the outer pipe (6).

6. The gas preheating device for efficient recovery and utilization of waste heat according to claim 1, characterized in that: A high-temperature resistant ring gasket (17) is provided between the tube sheet (3) above the gas collection chamber (13) and the outer tube (6).

Images