Device suitable for high-pressure rich liquid energy recovery of low-temperature methanol washing system

Abstract

The utility model discloses a device suitable for low temperature methanol washing system high pressure rich liquid energy recovery, include: shift gas washing tower is used for removing gas impurity in shift gas, and output rich hydrogen sulfide methanol liquid and rich carbon dioxide methanol liquid, shift gas washing tower is connected to the sulfur section and sulfurless section liquid inlet line of medium pressure flash tower through two first pipelines respectively, all are provided with pressure reducing valve on two first pipelines, and all are led out a branch on two pipelines, and the import of two branches all are located pressure reducing valve front end, and the export is connected to the sulfurless section and sulfur section liquid inlet line of medium pressure flash tower respectively, and the common liquid turbine unit is provided on two branches, and the liquid turbine unit is connected with generator. Through the device of the utility model can effectively recover the pressure energy in the pressure reduction process of rich methanol liquid, and convert it into electric energy, reduce enterprise power consumption, improve the energy utilization efficiency of whole process.

Description

Technical Field

[0001] This utility model belongs to the technical field of low-temperature methanol washing devices, and relates to a device suitable for high-pressure rich liquid energy recovery in low-temperature methanol washing systems. Background Technology

[0002] In the low-temperature methanol washing process, the conventional operation for treating the methanol-rich liquid that has absorbed hydrogen sulfide and carbon dioxide in the shift gas scrubbing tower is to directly depressurize it using a pressure-reducing valve before sending it to the medium-pressure flash distillation tower. This method results in the waste of a large amount of pressure energy contained in the methanol-rich liquid during the depressurization process, without effective utilization. As chemical plants continue to expand in scale, the total amount of such energy loss is also increasing, causing serious resource waste and increasing production costs. Furthermore, the depressurization of the methanol-rich liquid relies on the throttling of the level control valve. Prolonged operation leads to accelerated valve wear, resulting in frequent valve replacements, increased maintenance costs, and plant downtime due to valve repairs, which affects production continuity and efficiency. In the current environment of intense competition in the chemical industry and companies' pursuit of cost reduction and efficiency improvement, how to effectively recover the energy from the depressurization process of methanol-rich liquid and convert it into usable electrical energy has become a critical issue that chemical companies urgently need to address. Utility Model Content

[0003] The purpose of this invention is to provide a device for energy recovery of high-pressure rich liquid in a low-temperature methanol washing system. This device can effectively recover the pressure energy during the decompression process of rich methanol liquid and convert it into electrical energy, thereby reducing the company's power consumption and improving the energy utilization efficiency of the entire process.

[0004] The technical solution adopted in this utility model is: Devices suitable for energy recovery from high-pressure rich liquor in low-temperature methanol washing systems include: The shift gas scrubbing tower is used to remove gaseous impurities from the shift gas and output hydrogen sulfide-rich methanol liquid and carbon dioxide-rich methanol liquid. The shift gas scrubbing tower is connected to the inlet pipelines of the sulfur-containing section and the sulfur-free section of the medium-pressure flash evaporator via two first pipelines, respectively. Both first pipelines are equipped with pressure reducing valves, and each pipeline has a branch line. The inlet of each branch line is located in front of the pressure reducing valve, and the outlet is connected to the inlet pipeline of the sulfur-free section and the sulfur-containing section of the medium-pressure flash evaporator, respectively. A hydraulic turbine unit is installed on both branches, and the hydraulic turbine unit is connected to a generator.

[0005] The features of this utility model also include: Both branches include a second pipeline. One end of the second pipeline is connected to the first pipeline, and the other end is connected to the hydraulic turbine unit. The hydraulic turbine unit is then connected to the inlet pipelines of the sulfur-free section and the sulfur-containing section of the medium-pressure flash evaporator through two third pipelines, respectively.

[0006] The hydraulic turbine unit adopts a coaxial structure with two impellers, which includes a methanol chamber containing hydrogen sulfide and a methanol chamber containing carbon dioxide. The two impellers are arranged in the two chambers respectively and share a drive shaft.

[0007] The drive shaft of the hydraulic turbine unit is connected to the generator.

[0008] Both the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber are equipped with inlets and outlets. Two second pipes are connected to the two inlets respectively, and two third pipes are connected to the two outlets respectively.

[0009] Both the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber are equipped with exhaust ports at the bottom.

[0010] An isolation chamber is provided between the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber. The side wall of the isolation chamber is connected to the drive shaft by a labyrinth seal structure. The isolation fluid is high-pressure lean methanol regenerated from a low-temperature methanol washing system. An isolation fluid inlet is provided at the bottom of the isolation chamber.

[0011] The hydraulic turbine unit is equipped with safety protection interlocks for overspeed, shaft temperature, shaft vibration, speed, and inlet / outlet pressure difference. Both second pipelines are equipped with emergency shut-off valves, manual regulating valves, and bypass liquid level regulating valves.

[0012] The beneficial effects of this utility model are: (1) The device of this utility model converts the pressure energy of the high-pressure methanol-rich liquid in the shift gas scrubbing tower into mechanical energy through an integrated coaxial hydraulic turbine unit, drives the generator to generate electricity, and the generated electricity is processed by the power equipment and then connected to the company's internal power grid. This effectively solves the problems of energy waste and high valve maintenance costs in the existing technology of methanol-rich liquid decompression process, realizes the recovery and utilization of methanol-rich liquid energy and energy saving and consumption reduction, and improves the economic benefits of the enterprise and the energy utilization efficiency of the entire process. (2) The hydraulic turbine unit in this utility model adopts a coaxial design, which makes the entire device structure more compact, occupies less space, and reduces the area required for equipment installation. At the same time, this design reduces the number of connecting parts between the equipment, reduces the risk of equipment failure due to loose connections, and improves the stability and reliability of the equipment during operation. In addition, the compact structure and optimized design of key components reduce the number of maintenance points and make maintenance more convenient. Furthermore, due to the improved operational stability of the equipment, the failure frequency is reduced, the number of repairs and maintenance costs are also reduced, extending the service life of the equipment and reducing the equipment maintenance and replacement costs for enterprises. (3) In this utility model device, an isolation chamber is provided between the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber of the hydraulic turbine unit, and lean methanol is used as the isolation liquid. This can effectively prevent the cross-flow of the two rich methanol liquids. Furthermore, if any one of the media has a problem, the other one will not be affected. In contrast, in the existing split hydraulic turbine unit, if one of the media has a problem, the whole unit must stop working. Therefore, this utility model device achieves high efficiency, safety and stability in operation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the device of this utility model.

[0014] In the diagram, 1. Hydraulic turbine unit, 2. Generator, 3. Emergency shut-off valve, 4. Manual regulating valve, 5. Bypass level regulating valve, 6. First pipeline, 7. Pressure reducing valve, 8. Second pipeline, 9. Shift gas scrubbing tower, 10. Medium-pressure flash evaporator, 11. Third pipeline. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] Example 1: This invention relates to a device for energy recovery from high-pressure rich liquor in a low-temperature methanol washing system, with the structure as follows: Figure 1 As shown, the system includes a hydraulic turbine unit 1, a shift gas scrubbing tower 9, a medium-pressure flash distillation tower 10, and a generator 2. The shift gas scrubbing tower 9 removes impurities such as CO2 and H2S from the shift gas, forming a high-pressure methanol-rich liquid that has absorbed hydrogen sulfide and carbon dioxide. The shift gas scrubbing tower 9 is connected to the medium-pressure flash distillation tower 10 via two first pipes 6. These two first pipes 6 are respectively connected to the inlet pipes of the sulfur-containing section and the sulfur-free section of the medium-pressure flash distillation tower 10, used to transport the hydrogen sulfide-rich methanol liquid and the carbon dioxide-rich methanol liquid discharged from the shift gas scrubbing tower 9 to the medium-pressure flash distillation tower 10.

[0017] Both first pipelines 6 are equipped with pressure reducing valves 7. The pressure reducing valves 7 are closed during normal operation of the device. Only when the energy recovery fails will the pressure reducing valves 7 automatically open to the preset valve position to release the pressure of the hydrogen sulfide-rich methanol liquid and the carbon dioxide-rich methanol liquid, so as to ensure the continuous operation of the entire low-temperature methanol washing system and prevent it from shutting down.

[0018] Each of the two first pipelines 6 has a branch line leading out. The inlet of each branch line is located at the front end of the pressure reducing valve 7. The other end of each branch line is connected to the inlet pipeline of the sulfur-free section and the sulfur-containing section of the medium-pressure flash tower 10, respectively. A hydraulic turbine unit 1 is installed on both branches.

[0019] Both branches include a second pipe 8, one end of which is connected to the first pipe 6, and the other end is connected to the hydraulic turbine unit 1. The hydraulic turbine unit 1 is then connected to the sulfur-free section and sulfur-containing section inlet pipes of the medium-pressure flash tower 10 through two third pipes 11 respectively.

[0020] The hydraulic turbine unit 1 is an integrated coaxial hydraulic turbine unit with a dual-impeller coaxial structure. The unit includes two chambers: a hydrogen sulfide-rich methanol chamber and a carbon dioxide-rich methanol chamber. The two impellers are arranged in the two chambers respectively and share a common drive shaft. Each chamber has an inlet and an outlet. Two second pipes 8 are connected to the two inlets respectively, and two third pipes 11 are connected to the two outlets respectively. These pipes are used to transport hydrogen sulfide-rich methanol and carbon dioxide-rich methanol to the two chambers of the hydraulic turbine unit 1. Within the chambers, the pressure energy of the two methanol-rich liquids is converted into mechanical energy before being transported to the medium-pressure flash distillation tower 10.

[0021] An isolation chamber is provided between the two chambers of the hydraulic turbine unit 1 to prevent cross-contamination of the two methanol-rich liquids. The sidewall of the isolation chamber is connected to the drive shaft using a labyrinth seal structure. The isolation fluid is high-pressure lean methanol regenerated from a low-temperature methanol washing system. An isolation fluid inlet is located at the bottom of the isolation chamber. Lean methanol enters the isolation chamber directly through this inlet via a pipeline, and after being depressurized by the labyrinth seal, it flows into the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber respectively. This effectively replaces the traditional mechanical seal (simple interstage seal) and prevents cross-contamination of media. Furthermore, the mechanical seals at both the drive and non-drive ends are cooled by a lean methanol siphon circulation flushing system, and circulating water is used to cool the sealing fluid, ensuring the long-term operation of both the drive and non-drive end mechanical seals.

[0022] The bottom of both chambers in the hydraulic turbine unit 1 is equipped with a drain port for easy replacement and drainage during maintenance.

[0023] The inlets of the hydrogen sulfide-rich methanol and carbon dioxide-rich methanol pipelines (i.e., the two second pipelines 8) of the hydraulic turbine unit 1 are equipped with an emergency shut-off valve 3, a manual regulating valve 4, and a bypass level regulating valve 5. The emergency shut-off valve 3 is a quick-closing valve that can cut off the inlet medium of the hydraulic turbine within three seconds to prevent damage to the unit due to overspeed. The manual regulating valve 4 is used to regulate the flow rate of the rich methanol entering the unit. The bypass level regulating valve 5 is used to control the liquid level of the desulfurization section and the decarbonization section of the shift gas scrubbing tower 9.

[0024] The hydraulic turbine unit 1 is equipped with safety protection interlocks for overspeed, shaft temperature, shaft vibration, speed, inlet and outlet pressure difference, and emergency stop. When the shutdown interlock is triggered, the emergency shut-off valve 3 closes quickly, and the unit stops after losing power. At this time, the pressure reducing valve 7 on the first pipeline 6 automatically opens to the preset valve position, preventing the shutdown of the low-temperature methanol washing system.

[0025] The drive shaft of the hydraulic turbine unit 1 is connected to a generator 2, which can convert mechanical energy into electrical energy. The generated electrical energy is processed by the supporting power transformation equipment and then fed into the company's internal power grid for use by other users.

[0026] The working principle of this utility model device is as follows: When the low-temperature methanol washing system is running, the high-pressure rich methanol liquid, which has absorbed hydrogen sulfide and carbon dioxide in the shift gas scrubbing tower 9, enters the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber of the hydraulic turbine unit 1 under pressure. Each chamber works on its corresponding impeller, using its own pressure energy to drive the impeller to rotate at high speed. At this point, the pressure energy of the rich methanol liquid is converted into mechanical energy. The impeller drives the turbine's drive shaft to rotate, which in turn drives the generator 2, achieving the conversion of potential energy into mechanical energy into electrical energy. The generated electrical energy is processed by the matching power transmission equipment and then fed into the company's internal power grid. Simultaneously, lean methanol with a higher pressure is used as a separator between the two rich liquids containing different media, ensuring that the two rich liquids do not affect each other.

[0027] During this process, the pressure of the methanol-rich liquid decreases, and after depressurization, it enters the sulfur-free section and sulfur-containing section of the medium-pressure flash distillation tower 10 to continue the subsequent process flow.

[0028] This invention effectively recovers and utilizes the pressure energy of methanol-rich liquid, reducing the company's consumption of external electrical energy, while also reducing the frequency of use of pressure-reducing valves and lowering valve maintenance costs.

[0029] The operation of this utility model device is as follows: Start the cryogenic methanol washing system. After the system stabilizes, slowly introduce the high-pressure rich methanol liquid from the shift gas scrubbing tower 9 into the integrated coaxial hydraulic turbine unit 1. Operators must closely monitor the unit's operating parameters, such as speed and inlet / outlet pressure, to ensure they operate within normal ranges. Simultaneously, monitor the generator's power output, voltage, and current.

[0030] When the system is running normally, the isolation liquid is fully opened, the emergency shut-off valve 3 and manual regulating valve 4 of the hydrogen sulfide-rich methanol pipeline and the carbon dioxide-rich methanol pipeline inlet are fully opened, and the liquid level of the shift gas scrubbing tower 9 is controlled by two bypass liquid level regulating valves 5.

[0031] The maintenance and upkeep of this utility model device are as follows: Regularly inspect the integrated coaxial hydraulic turbine unit 1, cleaning any internal impurities and checking the wear of key components such as impellers and bearings. Replace any severely worn components promptly. Inspect the connecting pipelines for leaks, corrosion, or other problems, and address them immediately. Regularly maintain the generator and transformer equipment, checking the reliability of electrical connections and performing dust removal, lubrication, and other maintenance to ensure the stable operation of the entire energy recovery system.

[0032] Example 2: This embodiment applies to a device for energy recovery of high-pressure rich liquor in a low-temperature methanol washing system, including: The shift gas scrubbing tower 9 is used to remove gaseous impurities from the shift gas and output hydrogen sulfide-rich methanol liquid and carbon dioxide-rich methanol liquid. The shift gas scrubbing tower 9 is connected to the inlet pipes of the sulfur-containing section and the sulfur-free section of the medium-pressure flash tower 10 through two first pipes 6 respectively; Both first pipelines 6 are equipped with pressure reducing valves 7, and each pipeline has a branch line leading out. The inlet of each branch line is located at the front end of the pressure reducing valve 7, and the outlet is connected to the inlet pipeline of the sulfur-free section and the sulfur-containing section of the medium-pressure flash tower 10, respectively. A hydraulic turbine unit 1 is installed on both branches, and a generator 2 is connected to the hydraulic turbine unit 1.

[0033] Example 3: Based on Example 2, both branches include a second pipe 8. One end of the second pipe 8 is connected to the first pipe 6, and the other end is connected to the hydraulic turbine unit 1. The hydraulic turbine unit 1 is then connected to the sulfur-free section and sulfur-containing section inlet pipes of the medium-pressure flash tower 10 through two third pipes 11 respectively.

[0034] Example 4: Based on Example 3, the hydraulic turbine unit 1 adopts a dual-impeller coaxial structure, which includes a methanol chamber containing hydrogen sulfide and a methanol chamber containing carbon dioxide. The two impellers are respectively arranged in the two chambers and the two impellers share a drive shaft.

[0035] Example 5: This embodiment applies to a device for energy recovery of high-pressure rich liquor in a low-temperature methanol washing system, including: The shift gas scrubbing tower 9 is used to remove gaseous impurities from the shift gas and output hydrogen sulfide-rich methanol liquid and carbon dioxide-rich methanol liquid. The shift gas scrubbing tower 9 is connected to the inlet pipes of the sulfur-containing section and the sulfur-free section of the medium-pressure flash tower 10 through two first pipes 6 respectively; Both first pipelines 6 are equipped with pressure reducing valves 7, and each pipeline has a branch line leading out. The inlet of each branch line is located at the front end of the pressure reducing valve 7, and the outlet is connected to the inlet pipeline of the sulfur-free section and the sulfur-containing section of the medium-pressure flash tower 10, respectively. A hydraulic turbine unit 1 is installed on both branches, and a generator 2 is connected to the hydraulic turbine unit 1.

[0036] Both branches include a second pipe 8, one end of which is connected to the first pipe 6, and the other end is connected to the hydraulic turbine unit 1. The hydraulic turbine unit 1 is then connected to the sulfur-free section and sulfur-containing section inlet pipes of the medium-pressure flash tower 10 through two third pipes 11 respectively.

[0037] The hydraulic turbine unit 1 adopts a coaxial structure with two impellers, which includes a methanol chamber containing hydrogen sulfide and a methanol chamber containing carbon dioxide. The two impellers are arranged in the two chambers respectively and the two impellers share a drive shaft.

[0038] The drive shaft of the hydraulic turbine unit 1 is connected to the generator 2.

[0039] Both the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber are equipped with inlets and outlets. Two second pipes 8 are connected to the two inlets respectively, and two third pipes 11 are connected to the two outlets respectively.

[0040] Example 6: This embodiment applies to a device for energy recovery of high-pressure rich liquor in a low-temperature methanol washing system, including: The shift gas scrubbing tower 9 is used to remove gaseous impurities from the shift gas and output hydrogen sulfide-rich methanol liquid and carbon dioxide-rich methanol liquid. The shift gas scrubbing tower 9 is connected to the inlet pipes of the sulfur-containing section and the sulfur-free section of the medium-pressure flash tower 10 through two first pipes 6 respectively; Both first pipelines 6 are equipped with pressure reducing valves 7, and each pipeline has a branch line leading out. The inlet of each branch line is located at the front end of the pressure reducing valve 7, and the outlet is connected to the inlet pipeline of the sulfur-free section and the sulfur-containing section of the medium-pressure flash tower 10, respectively. A hydraulic turbine unit 1 is installed on both branches, and a generator 2 is connected to the hydraulic turbine unit 1.

[0041] Both branches include a second pipe 8, one end of which is connected to the first pipe 6, and the other end is connected to the hydraulic turbine unit 1. The hydraulic turbine unit 1 is then connected to the sulfur-free section and sulfur-containing section inlet pipes of the medium-pressure flash tower 10 through two third pipes 11 respectively.

[0042] The hydraulic turbine unit 1 adopts a coaxial structure with two impellers, which includes a methanol chamber containing hydrogen sulfide and a methanol chamber containing carbon dioxide. The two impellers are arranged in the two chambers respectively and the two impellers share a drive shaft.

[0043] The drive shaft of the hydraulic turbine unit 1 is connected to the generator 2.

[0044] Both the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber are equipped with inlets and outlets. Two second pipes 8 are connected to the two inlets respectively, and two third pipes 11 are connected to the two outlets respectively.

[0045] Both the hydrogen sulfide methanol chamber and the carbon dioxide methanol chamber are equipped with exhaust ports at the bottom.

Claims

1. A device suitable for high-pressure rich liquor energy recovery in low-temperature methanol washing systems, characterized in that, include: The shift gas scrubbing tower (9) is used to remove gaseous impurities from the shift gas and output hydrogen sulfide-rich methanol liquid and carbon dioxide-rich methanol liquid. The shift gas scrubbing tower (9) is connected to the sulfur-containing section and sulfur-free section inlet pipes of the medium-pressure flash tower (10) through two first pipes (6); Pressure reducing valves (7) are installed on both first pipelines (6), and a branch is led out from each of the two pipelines. The inlet of each branch is located at the front end of the pressure reducing valve (7), and the outlet is connected to the sulfur-free section and sulfur-containing section liquid inlet pipeline of the medium-pressure flash tower (10), respectively. A hydraulic turbine unit (1) is installed on both branches, and a generator (2) is connected to the hydraulic turbine unit (1).

2. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 1, characterized in that, Both of the aforementioned branches include a second pipe (8), one end of which is connected to the first pipe (6), and the other end is connected to the hydraulic turbine unit (1). The hydraulic turbine unit (1) is then connected to the sulfur-free section and sulfur-containing section inlet pipes of the medium-pressure flash tower (10) via two third pipes (11).

3. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 2, characterized in that, The hydraulic turbine unit (1) adopts a double impeller coaxial structure, which includes a methanol chamber containing hydrogen sulfide and a methanol chamber containing carbon dioxide. The two impellers are arranged in the two chambers respectively and the two impellers share a drive shaft.

4. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 3, characterized in that, The drive shaft of the hydraulic turbine unit (1) is connected to the generator (2).

5. The device suitable for high pressure rich solution energy recovery of the rectisol system according to claim 3, characterized in that, Both the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber are equipped with inlets and outlets. Two second pipes (8) are connected to the two inlets respectively, and two third pipes (11) are connected to the two outlets respectively.

6. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 5, characterized in that, Both the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber are equipped with exhaust ports at their bottoms.

7. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 5, characterized in that, An isolation chamber is provided between the hydrogen sulfide-containing methanol chamber and the carbon dioxide-containing methanol chamber. The side wall of the isolation chamber is connected to the drive shaft using a labyrinth seal structure. The isolation fluid is high-pressure lean methanol regenerated from a low-temperature methanol washing system. An isolation fluid inlet is provided at the bottom of the isolation chamber.

8. The device for high-pressure rich liquor energy recovery in a low-temperature methanol washing system according to claim 2, characterized in that, The hydraulic turbine unit (1) is equipped with overspeed, shaft temperature, shaft vibration, speed and inlet / outlet pressure differential safety protection interlocks, and both second pipelines (8) are equipped with emergency shut-off valves (3), manual regulating valves (4) and bypass liquid level regulating valves (5).

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