Novel methanol washing power turbine system

Abstract

The invention relates to the technical field of methanol washing, and discloses a novel methanol washing hydraulic turbine system which comprises a first hydraulic turbine unit and a second hydraulic turbine unit, the first hydraulic turbine unit is mechanically connected with a pump, the second hydraulic turbine unit is mechanically connected with a generator, and the system is provided with a sulfur-containing methanol-rich pipeline and a sulfur-free methanol-rich pipeline. The two pipelines divide fluid into two strands to be input into the two hydraulic turbine units, and the fluid is converged and output through the sulfur-containing methanol-rich discharge pipe and the sulfur-free methanol-rich discharge pipe after acting through a turbine. By the adoption of the symmetrically-arranged sulfur-containing and sulfur-free double-working-medium impeller set structure, axial thrust generated by reverse fluid impact is counteracted, and the problem of axial force unbalance existing in a traditional single-flow-channel turbine is effectively solved. Compared with the scheme depending on a high-pressure balance pipe or a complex thrust bearing in the prior art, the structure of the unit is simplified while the stability of the main shaft is guaranteed, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of methanol washing, and specifically to a novel methanol washing hydraulic turbine system. Background Art

[0002] In the petrochemical industry, the low-temperature methanol washing technology uses low-temperature methanol to wash acidic gases such as CO2, H2S, and COS in the shifted gas to obtain qualified purified gas for subsequent processes. The process is as follows: The shifted gas enters the washing tower from the bottom. Under the conditions of high pressure and low temperature, lean methanol is introduced into the top of the washing tower for washing, so that purified gas is obtained in the upper part of the washing tower; the rich methanol after washing first undergoes pressure reduction, and the absorbed effective gas is desorbed in the medium-pressure tower, and then further pressure reduction is carried out to desorb CO2. Finally, after nitrogen stripping, the rich methanol is regenerated into lean methanol in the heat regeneration unit and recycled back to the washing tower for use.

[0003] Among them, the rich methanol from the washing tower is in two streams, namely sulfur-containing rich methanol and sulfur-free rich methanol, both with a pressure of about 5.5 MPa. After the pressure is reduced to 1.0 MPa, it is sent to the next process section to flash out the effective gas dissolved in methanol. Before the rich methanol is depressurized and enters the next process section, there is a pressure drop of about 4.5 MPa. If the pressure reduction is directly carried out through a pressure reducing valve, not only this part of the pressure energy is wasted, but also the cold energy of the rich methanol is lost. Therefore, in industry, a hydraulic turbine is used to convert this part of the pressure energy into mechanical energy, and at the same time, part of the cold energy of the rich methanol is recovered by using the turbine unit.

[0004] At present, there are various solutions in the industry, such as "pump + double-extended motor + clutch + hydraulic turbine", "pump + hydraulic turbine", "pump + generator", etc., for recovering the pressure energy of the rich methanol from the washing tower. However, no matter which solution is used, it is necessary to carry out the research and manufacture of equipment according to the actual operating parameters of the methanol washing system, resulting in that the unit can only reach the best operating state under specific conditions, and the unit has poor adjustment ability. Especially under the condition of using the hydraulic turbine unit to drive the pump, once the methanol washing system has an abnormality, it may affect the operation of the pump and cause instability of multiple systems. On the other hand, due to the rapid pressure reduction of the rich methanol, it will cause the rich methanol to be desorbed and flashed, resulting in unstable axial force of the turbine unit and affecting the stable operation of the turbine unit. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a novel methanol washing hydraulic turbine system, which solves the problem of axial force imbalance existing in traditional single-channel turbines.

[0006] To achieve the above object, the present invention is realized through the following technical solutions: A new type of methanol scrubbing hydraulic turbine system includes a hydraulic turbine unit one and a hydraulic turbine unit two. The hydraulic turbine unit one is mechanically connected to a pump, and the hydraulic turbine unit two is mechanically connected to a generator. The system is provided with a sulfur-rich methanol pipeline and a sulfur-free rich methanol pipeline. The two pipelines divide the fluid into two streams and input them into the two hydraulic turbine units respectively. After passing through the turbine to do work, they are combined and output through the sulfur-rich methanol discharge pipe and the sulfur-free rich methanol discharge pipe.

[0007] Furthermore, the split flow conduction design realizes the load balance of the turbine units through fluid equal division. The dual-unit parallel structure ensures the continuous operation ability of the system during single-unit maintenance. The split flow processing mechanism effectively isolates the cross influence of sulfur-containing and sulfur-free media.

[0008] Preferably, the hydraulic turbine unit one is provided with symmetrically arranged impellers one and two, and the hydraulic turbine unit two is provided with symmetrically arranged impellers three and four. The impeller one and the impeller three are connected to the sulfur-rich methanol pipeline, and the impeller two and the impeller four are connected to the sulfur-free rich methanol pipeline.

[0009] Furthermore, the symmetric impeller group adopts a differentiated flow channel design. The sulfur-containing medium flow channel is configured with an anti-corrosion surface treatment, and the sulfur-free medium flow channel adopts an optimized fluid dynamics profile to achieve efficient energy conversion of working fluids with different characteristics.

[0010] Preferably, the sulfur-rich methanol pipeline is provided with a flow valve before entering the hydraulic turbine unit, and the sulfur-free rich methanol pipeline is provided with a flow valve before entering the hydraulic turbine unit.

[0011] Furthermore, the independent flow regulation mechanism realizes the dynamic balance of the two fluid streams through a pressure feedback control system, ensures the matching of the working fluid pressure at the turbine inlet, and eliminates the fluid backflow phenomenon caused by the pressure difference.

[0012] Preferably, the sulfur-rich methanol pipeline is paralleled with a sulfur-rich methanol sub-pipeline, and the sulfur-free rich methanol pipeline is paralleled with a sulfur-free rich methanol sub-pipeline. The sub-pipeline is provided with a pressure reducing valve and a flow valve.

[0013] Furthermore, the sub-pipeline system constitutes a pressure buffer network, and maintains the system pressure stability through split flow and pressure reduction when the main passage regulation is limited. This design is particularly suitable for the variable load operation characteristics of the methanol scrubbing process.

[0014] Preferably, the impeller one and the impeller two form a first impeller group, and the impeller three and the impeller four form a second impeller group. The two groups of impellers are symmetrically installed on the same main shaft.

[0015] Furthermore, the coaxial integration design enables the dual impeller group to form physically isolated independent working chambers, while ensuring the axial uniformity of torque transmission and eliminating the torsional vibration coupling problem of traditional multi-stage turbines.

[0016] Preferably, the axial thrust directions of the first impeller and the second impeller are opposite, and the axial thrust directions of the third impeller and the fourth impeller are opposite, and the two groups of impellers share the same main shaft.

[0017] Furthermore, the reverse thrust structure achieves self - balance of the axial force, greatly reducing the axial load on the main shaft bearings, enabling the turbine unit to adopt a more compact support structure design.

[0018] Preferably, the flow valve is configured to adjust the fluid flow rate entering the hydraulic turbine unit to maintain the stable output power of the pump.

[0019] Furthermore, the flow control system establishes a multi - parameter collaborative control model of pump power and turbine inlet pressure, and maintains the operating stability of the pumping system through real - time compensation adjustment.

[0020] Preferably, the energy conversion path of the first hydraulic turbine unit is pressure energy - mechanical energy, and the energy conversion path of the second hydraulic turbine unit is pressure energy - mechanical energy - electrical energy.

[0021] Furthermore, the design of different energy conversion paths enables the pump drive system to obtain a fast dynamic response ability, and at the same time, the power generation system forms an adjustable flexible energy output interface.

[0022] Preferably, the sulfur - rich methanol discharge pipe and the sulfur - free rich methanol discharge pipe are respectively connected to the inlet of the downstream flashing section.

[0023] Furthermore, the special structure design of the discharge pipeline utilizes the kinetic energy of the fluid itself to maintain the conveying pressure difference, realizing the self - balanced conveying of energy from the turbine outlet to the downstream section.

[0024] Preferably, the axial thrust directions of the symmetrically arranged first impeller group and the second impeller group are opposite, and the two groups of impellers share the same main shaft and no axial force balancing device is provided.

[0025] Furthermore, the axial force self - balance design eliminates the traditional balancing device, realizes the dynamic balance of the rotor system through the symmetric layout of the impeller group, and simplifies the mechanical structure of the turbine unit.

[0026] The present invention provides a new type of methanol scrubbing hydraulic turbine system, which has the following beneficial effects: 1. The present invention adopts a symmetrically arranged double - working - fluid impeller group structure of sulfur - containing and sulfur - free substances, and the axial thrusts generated by the reverse fluid impacts cancel each other out, effectively solving the axial force imbalance problem existing in traditional single - flow - channel turbines. Compared with the prior art solutions that rely on high - pressure balance pipes or complex thrust bearings, this design simplifies the unit structure while ensuring the stability of the main shaft and reducing the maintenance cost.

[0027] 2. The present invention provides a main and auxiliary dual-fluid passage, combined with the coordinated control of a flow valve and a pressure reducing valve, to achieve hierarchical recovery and emergency diversion of the energy of the working medium. Compared with the defect that the traditional single-passage system is prone to cause equipment overload during sudden changes in working conditions, this solution maintains the efficient work of the turbine and ensures the stability of the downstream process pressure through a dynamic flow distribution mechanism.

[0028] 3. The present invention constructs dual energy recovery paths of mechanical direct drive and electromechanical conversion respectively. Different from the efficiency loss caused by the single energy conversion mode in the prior art, this system maximizes the overall energy efficiency of the system by distinguishing the direct drive of key equipment and the flexible conversion of surplus energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the present invention.

[0030] 1. Hydraulic turbine unit 1; 2. Pump; 3. Hydraulic turbine unit 2; 4. Generator; 5. Flow valve; 6. Pressure reducing valve; 7. Impeller 1; 8. Impeller 2; 9. Impeller 3; 10. Impeller 4; 11. Sulfur-rich methanol pipeline; 12. Sulfur-rich methanol discharge pipe; 13. Sulfur-free methanol pipeline; 14. Sulfur-free methanol discharge pipe. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0032] Please refer to the attached Figure 1 , an embodiment of the present invention provides a new type of methanol washing hydraulic turbine system, including a hydraulic turbine unit 1 and a hydraulic turbine unit 2. The hydraulic turbine unit 1 is mechanically connected to the pump 2, and the hydraulic turbine unit 2 is mechanically connected to the generator 4. The system is provided with a sulfur-rich methanol pipeline 11 and a sulfur-free methanol pipeline 13. The two pipelines divide the fluid into two streams and input them into the two hydraulic turbine units respectively. After passing through the turbine, they are output after converging through the sulfur-rich methanol discharge pipe 12 and the sulfur-free methanol discharge pipe 14. Inside the hydraulic turbine unit 1, there are symmetrically arranged impellers 1 and 2, and inside the hydraulic turbine unit 2, there are symmetrically arranged impellers 3 and 4. The impeller 1 and the impeller 3 are connected to the sulfur-rich methanol pipeline 11, and the impeller 2 and the impeller 4 are connected to the sulfur-free methanol pipeline 13. A flow valve 5 is provided in front of the sulfur-rich methanol pipeline 11 before entering the hydraulic turbine unit, and a flow valve 5 is provided in front of the sulfur-free methanol pipeline 13 before entering the hydraulic turbine unit.

[0033] Specifically, the pressurized working medium transported by the sulfur-rich methanol pipeline 11 drives the rotation of impeller one 7 and impeller three 9. The working medium in the sulfur-free rich methanol pipeline 13 synchronously pushes impeller two 8 and impeller four 10 to rotate in the opposite direction. The four groups of impellers form a dynamically balanced torque output on the common main shaft. The flow valve 5 dynamically adjusts the flow ratio of the two working media according to the real-time working conditions, so that the pressure energy of the sulfur-containing and sulfur-free fluids is efficiently converted into the mechanical energy of the hydraulic turbine unit one 1 driving the pump 2 and the electrical energy of the hydraulic turbine unit two 3 driving the generator 4. The auxiliary pipeline system establishes a pressure buffer channel through the pressure reducing valve 6, and realizes the hierarchical release of the working medium energy when the main path flow rate suddenly changes. The reverse axial forces generated by the symmetrical impeller groups cancel each other out, enabling the main shaft system to maintain stable operation without configuring a traditional balancing device. The working medium after passing through the turbine and reducing the pressure is output to the downstream process at a constant pressure through the sulfur-rich methanol discharge pipe 12 and the sulfur-free rich methanol discharge pipe 14. This design realizes the three-stage utilization of pressure energy, giving priority to ensuring the stable output of the driving force of the pump 2, converting the surplus energy into electrical energy, and finally maintaining the pressure balance of the process system, forming a closed-loop energy management chain.

[0034] Please refer to the appendix Figure 1 , a sulfur-rich methanol auxiliary pipeline is connected in parallel to the sulfur-rich methanol pipeline 11, and a sulfur-free rich methanol auxiliary pipeline is connected in parallel to the sulfur-free rich methanol pipeline 13. The auxiliary pipelines are provided with a pressure reducing valve 6 and a flow valve 5. Impeller one 7 and impeller two 8 form the first impeller group, and impeller three 9 and impeller four 10 form the second impeller group. The two groups of impellers are symmetrically installed on the same main shaft. The axial thrust directions of impeller one 7 and impeller two 8 are opposite, and the axial thrust directions of impeller three 9 and impeller four 10 are opposite. And the two groups of impellers share the same main shaft. The flow valve 5 is configured to adjust the fluid flow rate entering the hydraulic turbine unit to maintain the stable output power of the pump 2. The energy conversion path of the hydraulic turbine unit one 1 is pressure energy - mechanical energy, and the energy conversion path of the hydraulic turbine unit two 3 is pressure energy - mechanical energy - electrical energy. The sulfur-rich methanol discharge pipe 12 and the sulfur-free rich methanol discharge pipe 14 are respectively connected to the inlet of the downstream flash evaporation section. The axial thrust directions of the symmetrically arranged first impeller group and the second impeller group are opposite. The two groups of impellers share the same main shaft and there is no axial force balancing device.

[0035] Specifically, the working fluids in the sulfur-rich methanol pipeline 11 and the sulfur-free rich methanol pipeline 13 respectively drive the first impeller 7, the third impeller 9 and the second impeller 8, the fourth impeller 10 to form a counter-flow field. The impeller groups rotating in opposite directions build a dynamic balance system on the common main shaft, and eliminate the hidden danger of axial displacement through the self-compensation effect of fluid kinetic energy; the flow valve 5 and the pressure reducing valve 6 form a multi-stage pressure regulation network. When the working fluid flow rate in the main passage fluctuates, the secondary pipeline system automatically opens the energy diversion channel, which not only ensures that the driving torque of the hydraulic turbine unit 1 on the pump 2 is constant, but also enables the power generation power of the hydraulic turbine unit 2 to be dynamically adjusted with the surplus energy; the dual energy recovery path design enables the pressure energy of the high-pressure working fluid to be preferentially converted into the driving force of the pump 2, and the remaining energy is flexibly output through the secondary electro-mechanical conversion; the working fluid after pressure reduction by the turbine enters the flashing process through the sulfur-rich methanol discharge pipe 12 and the sulfur-free rich methanol discharge pipe 14 to maintain a stable back pressure. This energy cascade utilization mode breaks through the bottleneck of single energy conversion in the traditional system, and the self-balancing characteristics of the impeller group and the dual-channel pressure regulation mechanism work together. Embodiment

[0036] Such as Figure 1 The methanol washing hydraulic turbine system shown in the figure includes a hydraulic turbine unit 1, a pump 2, a hydraulic turbine unit 2, a generator 4, and a flow valve 5.

[0037] The hydraulic turbine unit 1 drives the pump 2, and the hydraulic turbine unit 2 drives the generator 4.

[0038] The hydraulic turbine unit 1 has two symmetrically placed first impellers 7 and a second impeller 8, and the hydraulic turbine unit 2 has two symmetrically placed third impellers 9 and a fourth impeller 10.

[0039] The high-pressure sulfur-free rich methanol from the washing tower is divided into two paths and enters the second impeller 8 and the third impeller 9, and a flow valve 5 is provided on each path.

[0040] The high-pressure sulfur-rich methanol from the washing tower is divided into two paths and enters the first impeller 7 and the fourth impeller 10, and a flow valve 5 is provided on each path.

[0041] The impellers of the hydraulic turbine unit 1 and the hydraulic turbine unit 2 are symmetrically placed. Since the working conditions of the sulfur-rich methanol and the sulfur-free rich methanol coming out of the washing tower are almost the same, the axial thrusts at both ends cancel each other out, so that the high-pressure balance pipe does not need to be set for this unit, thereby reducing the volume loss of the turbine unit and increasing the unit efficiency. On the other hand, due to the similar working conditions at both ends of the turbine unit, the influence of the unstable axial force of the main shaft caused by the flashing of the rich methanol under reduced pressure is also solved.

[0042] Since the hydraulic turbine unit 1 directly drives the pump 2, its efficiency is higher than that of the hydraulic turbine unit 2 for power generation, and the power change of the hydraulic turbine unit 2 has less impact on other systems. Therefore, in actual production, the operation of the hydraulic turbine unit 1 can be preferentially ensured by adjusting the flow valve 5 to increase the system efficiency.

[0043] The presence of the flow valve 5 can ensure that the amount of rich methanol passing through the two turbine units is adjusted according to production needs to meet different production requirements.

[0044] The operation mode of this system is as follows: The high-pressure sulfur-rich methanol and high-pressure sulfur-free rich methanol from the scrubber are each divided into two paths and enter the hydraulic turbine unit 1 and the hydraulic turbine unit 2. After the high-pressure methanol does work through the turbine unit, the pressure decreases and it enters the next process. The two turbine units drive the pump 2 and the generator 4 respectively to recover the pressure energy of the high-pressure rich methanol. Embodiment

[0045] Based on Embodiment 1, Embodiment 2 is provided with a sulfur-free rich methanol sub-pipeline and a sulfur-rich methanol sub-pipeline, and a flow valve 5 and a pressure reducing valve 6 are provided on each pipeline. The existence of the sub-pipeline can ensure that the high-pressure rich methanol can enter the next process without passing through the two turbine units; at the same time, the existence of the sub-pipeline can be used to adjust the output power of the pump 2 or the generator 4.

[0046] Working principle: The sulfur-rich methanol pipeline 11 and the sulfur-free rich methanol pipeline 13 divide the working medium from the scrubber into two streams respectively. After being adjusted by the flow valve 5, they enter the hydraulic turbine unit 1 and the hydraulic turbine unit 2; the sulfur-containing working medium drives the impeller 1 and the impeller 3 to rotate, and the sulfur-free working medium drives the impeller 2 and the impeller 4 to rotate in the opposite direction. The axial thrusts generated by the two groups of impellers cancel each other out to achieve self-balancing of the main shaft; the working medium after doing work is collected through the sulfur-rich methanol discharge pipe 12 and the sulfur-free rich methanol discharge pipe 14 and transported to the flashing section; the hydraulic turbine unit 1 drives the pump 2 to operate through mechanical direct drive, and the hydraulic turbine unit 2 drives the generator 4 for energy recovery; when the system pressure fluctuates, the sulfur-rich methanol sub-pipeline and the sulfur-free rich methanol sub-pipeline divert part of the working medium through the pressure reducing valve 6, and the flow valve 5 synchronously adjusts the flow ratio of the main and sub-pipelines to maintain the stable output of the pump 2; the symmetrically arranged impeller groups form a reverse torque on the common main shaft, eliminating the hidden danger of axial displacement of the traditional turbine; during the whole process, the double-turbine units respectively perform direct utilization of mechanical energy and flexible conversion of electric energy to achieve efficient hierarchical recovery of pressure energy.

[0047] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new type of methanol washing hydraulic turbine system, characterized in that It includes a hydraulic turbine unit one (1) and a hydraulic turbine unit two (3). The hydraulic turbine unit one (1) is mechanically connected to a pump (2), and the hydraulic turbine unit two (3) is mechanically connected to a generator (4). The system is provided with a sulfur-rich methanol pipeline (11) and a sulfur-free rich methanol pipeline (13). The two pipelines divide the fluid into two streams and input them into the two hydraulic turbine units respectively. After the turbines do work, they are combined and output through a sulfur-rich methanol discharge pipe (12) and a sulfur-free rich methanol discharge pipe (14).

2. The novel methanol washing hydraulic turbine system according to claim 1, wherein Inside the hydraulic turbine unit one (1), there are symmetrically arranged impellers one (7) and impellers two (8). Inside the hydraulic turbine unit two (3), there are symmetrically arranged impellers three (9) and impellers four (10). The impellers one (7) and impellers three (9) are connected to the sulfur-rich methanol pipeline (11), and the impellers two (8) and impellers four (10) are connected to the sulfur-free rich methanol pipeline (13).

3. A novel methanol washing hydraulic turbine system according to claim 1, characterized in that, Before entering the hydraulic turbine unit, the sulfur-rich methanol pipeline (11) is provided with a flow valve (5), and the sulfur-free rich methanol pipeline (13) is provided with a flow valve (5) before entering the hydraulic turbine unit.

4. A novel methanol washing hydraulic turbine system according to claim 1, characterized in that, The sulfur-rich methanol pipeline (11) is in parallel with a sulfur-rich methanol sub-pipeline, and the sulfur-free rich methanol pipeline (13) is in parallel with a sulfur-free rich methanol sub-pipeline. The sub-pipeline is provided with a pressure reducing valve (6) and a flow valve (5).

5. A novel methanol washing hydraulic turbine system according to claim 2, characterized in that, The impellers one (7) and impellers two (8) form a first impeller group, and the impellers three (9) and impellers four (10) form a second impeller group. The two groups of impellers are symmetrically installed on the same main shaft.

6. The novel methanol washing hydraulic turbine system according to claim 2, characterized in that, The axial thrust directions of the impellers one (7) and impellers two (8) are opposite, and the axial thrust directions of the impellers three (9) and impellers four (10) are opposite. And the two groups of impellers share the same main shaft.

7. A novel methanol washing hydraulic turbine system according to claim 4, characterized in that, The flow valve (5) is configured to adjust the fluid flow rate entering the hydraulic turbine unit to maintain the stable output power of the pump (2).

8. A novel methanol washing hydraulic turbine system according to claim 1, characterized in that, The energy conversion path of the hydraulic turbine unit one (1) is pressure energy - mechanical energy, and the energy conversion path of the hydraulic turbine unit two (3) is pressure energy - mechanical energy - electrical energy.

9. A novel methanol washing hydraulic turbine system according to claim 1, characterized in that, The sulfur-rich methanol discharge pipe (12) and the sulfur-free rich methanol discharge pipe (14) are respectively connected to the inlet of the downstream flashing section.

10. A novel methanol washing hydraulic turbine system according to claim 5, characterized in that, The axial thrust directions of the symmetrically arranged first impeller group and second impeller group are opposite. The two groups of impellers share the same main shaft and there is no axial force balancing device.

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