Natural gas component removal process system combined with ttpes and orc

Abstract

The present application relates to a kind of TTPES and ORC combined natural gas component removal process system, comprising: source gas pretreatment unit, TTPES natural gas component removal and pressure energy recycling unit, ORC cold energy recycling unit and electric energy management unit.It is characterized in that, TTPES natural gas component removal and pressure energy recycling unit includes heat exchanger, turbine expander, supersonic separator, generator and electric energy management unit, high-pressure natural gas after source gas pretreatment unit is handled and is passed into turbine expander by heat exchanger, drives generator rotation and converts pressure energy into electric energy, and is stored and utilized by electric energy management unit;After being passed through turbine expander, the natural gas of reduced pressure and temperature is passed into to supersonic separator and is further removed and handled, and the low-temperature natural gas after condensation separation by supersonic separator is handled by ORC cold energy recycling unit.

Description

Technical Field

[0001] This invention belongs to the field of natural gas component separation technology, and specifically relates to a wellhead natural gas component removal process system that combines TTPES (Transonic Two-Phase Expander and Separator) and ORC (Organic Rankine Cycle). Background Technology

[0002] Natural gas extracted from wellheads is a multi-component gas containing moisture, heavy hydrocarbons, CO2, H2S, and particulate matter. If not removed in time, moisture and heavy hydrocarbons can easily form hydrates during pipeline gathering and transportation, causing ice blockage in pipelines and valves. Acidic water droplets can corrode pipelines, reducing their service life. Existing natural gas component removal systems are based on membrane separation, molecular sieves, and triethylene glycol technologies. These systems are large in size, have high construction and operating costs, and the pressure and cold energy generated during the purification process are not effectively utilized. Therefore, a wellhead natural gas component removal process system combining TTPES and ORC was designed. TTPES achieves component separation of natural gas, while effectively utilizing the pressure and cold energy generated during the natural gas purification process to generate electricity for system use. This system reduces construction and operating costs while achieving energy conservation and emission reduction, and improving energy utilization efficiency. Summary of the Invention

[0003] One objective of this invention is to provide a low-cost, high-efficiency natural gas component removal process system; another objective is to provide a method for recovering and utilizing the pressure energy and cold energy of natural gas; furthermore, this invention also provides a means for regulating the pressure of the natural gas at the inlet of the process system through the reuse of waste gas. The technical solution is as follows:

[0004] A natural gas component removal process system combining TTPES and ORC includes: a source gas pretreatment unit, a TTPES natural gas component removal and pressure energy recovery unit, an ORC cold energy recovery unit, and an electrical energy management unit. The TTPES natural gas component removal and pressure energy recovery unit comprises a heat exchanger, a turboexpander, a supersonic separator, a generator, and an electrical energy management unit. High-pressure natural gas processed by the source gas pretreatment unit is fed into the turboexpander via the heat exchanger, driving the generator to convert pressure energy into electrical energy, which is then stored and utilized by the electrical energy management unit. Natural gas with reduced pressure and temperature after passing through the turboexpander is fed into the supersonic separator for further removal. Low-temperature natural gas after condensation and separation in the supersonic separator is then processed by the ORC cold energy recovery unit.

[0005] Furthermore, the ORC cold energy recovery and utilization unit includes a cryogenic condenser, a pump, a steam turbine, a gas heating and heat exchange device, a generator, and an energy management unit. The gas heating and heat exchange device generates heat from the natural gas processed by the combustion process system, and the generated heat provides a heat source for the ORC cycle working fluid. The cryogenic natural gas at the outlet of the supersonic separator provides a cold source for the ORC cycle. After the cryogenic condenser recovers and utilizes the cold energy, the steam turbine drives the generator to rotate and convert the pressure energy into electrical energy, which is then stored and utilized through the energy management unit.

[0006] Furthermore, the low-temperature natural gas, after being condensed and separated by the supersonic separator, is partially recycled to the front-end heat exchanger for inlet heat exchange.

[0007] Furthermore, the source gas pretreatment unit includes a gravity settling separator, through which some liquid moisture and solid particulate matter components are removed from the high-pressure natural gas source gas.

[0008] Furthermore, it also includes a membrane separation deep purification unit, which includes a membrane separator and a gas transmission pipeline. The low-temperature natural gas, after being condensed and separated by the supersonic separator, is then used by the low-temperature condenser of the inlet heat exchange or ORC cold energy recovery and utilization unit before being introduced into the membrane separator to achieve deep purification of the natural gas and obtain pure natural gas for gathering and transportation.

[0009] Furthermore, a portion of the purified natural gas obtained through the membrane separation deep purification unit is fed into the gas heating and heat exchange device within the ORC cycle for utilization, providing the necessary thermal energy for the ORC cycle.

[0010] Furthermore, it also includes an exhaust gas recirculation pressure regulating unit, through which exhaust gas discharged from the wet gas outlet of the supersonic separator is introduced; the exhaust gas recirculation pressure regulating unit includes a gas-liquid separator, a compressor and a pressure regulating valve, through which the exhaust gas obtained after being processed by the supersonic separator is introduced into the gas-liquid separator for secondary processing, and then the compressor is used to recirculate the secondary processed exhaust gas to the inlet of the turbine expander to merge with the heat-exchanged natural gas, and the pressure regulating valve is used to control and stabilize the natural gas source pressure at the inlet of the turbine expander.

[0011] Furthermore, the electrical energy obtained from the generator is stored in the power management unit to provide power to the power-consuming units within the process system.

[0012] The natural gas component removal process system of this invention has the advantages of low cost and high efficiency. It can effectively remove particulate impurities contained in wellhead natural gas. Utilizing TTPES, it achieves deep removal of components such as moisture, heavy hydrocarbons, and acid gases from natural gas. The pressure energy within the pipeline is recovered and utilized to generate electricity through a turbine expander, and the cold energy of the natural gas after supersonic separation is recovered and utilized through an ORC cycle to generate electricity. The generated electricity can be used by the compressor, pump, and sensing system of the process system. Furthermore, the inlet natural gas pressure is regulated by reusing waste gas, achieving efficient component removal while ensuring reliable operation of the process system. Attached Figure Description

[0013] Figure 1 Process system diagram

[0014] Figure 2 : Analysis Model Diagram Detailed Implementation

[0015] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0016] like Figure 1 The diagram shown is of a natural gas component removal process system, which includes: a source gas pretreatment unit, a TTPES natural gas component removal and pressure energy recovery and utilization unit, an ORC cold energy recovery and utilization unit, a waste gas recirculation and pressure regulation unit, and a membrane separation deep purification unit. All units are reliably connected to each other through natural gas pipelines.

[0017] The high-pressure source gas extracted from the wellhead is introduced into the gravity settling separator 3 after passing through the control valve 1. The gravity settling technology is used to pre-remove components such as liquid water and solid particles in the source gas to ensure the treatment effect and service life of subsequent processes. The gravity settling separator 3 is equipped with a drain port to discharge the separated material for subsequent treatment.

[0018] The pretreated natural gas from the source gas pretreatment unit enters the turbine expander 5 after passing through heat exchanger 4. Within the turbine expander 5, the natural gas is depressurized and cooled, converting pressure energy into mechanical energy, which drives generator 13 to generate electricity. This electrical energy is stored in the power management unit 14 for system use or external transmission. The inlet pressure of the turbine expander is monitored in real time by pressure sensor 2 and fed back to the control system. When the pressure sensor detects an increase in pressure, the system adjusts the source gas pressure of the process system by controlling the opening of valve 1. The depressurized and cooled natural gas from the turbine expander 5 is further introduced into the inlet of the supersonic separator 6. Utilizing the condensation separation effect within the supersonic separator 6, components such as water vapor, heavy hydrocarbons, CO2, and H2S contained in the natural gas are condensed into droplets. The cooling effect of the turbine expander 5 provides a better low-temperature environment for condensation separation within the supersonic separator 6, deepening the removal depth.

[0019] The gas is discharged from the moisture outlet and introduced into the gas-liquid separator 7. In addition, due to the Joule-Thomson effect during the component removal process of the supersonic separator 6, the temperature of the treated natural gas is significantly reduced, and it has a certain amount of usable cold energy. By opening valve 9, this part of the natural gas can be introduced into the inlet heat exchanger 4 to exchange heat with the pretreated natural gas, further reducing the temperature of the treated natural gas and improving the depth of component removal; it can also be introduced into the low-temperature condenser 18 in the ORC cycle by opening valve 8 to provide the required cold energy for the ORC cycle.

[0020] When valve 9 is opened and valve 8 is closed, natural gas is introduced into the inlet heat exchanger 4 to exchange heat with the pretreated natural gas. It then further enters the terminal membrane separator 12 to achieve deep removal of components such as water vapor, heavy hydrocarbons, CO2, and H2S, resulting in purer natural gas for gathering and transportation. A portion of the pure natural gas is then fed into the gas heating and heat exchange unit 16 within the ORC cycle for utilization, providing the necessary heat energy for the ORC cycle. The membrane separator 12 is equipped with a drain port to discharge the separated material for further processing. The gas heating and heat exchange unit consists of a natural gas heater and a heat exchanger. The natural gas heater generates heat through the combustion process of the treated natural gas, and the heat exchanger exchanges heat with the ORC cycle working fluid.

[0021] When valve 8 is opened and valve 9 is closed, natural gas is introduced into the condenser 18 of the ORC cycle, where it exchanges heat with the ORC cycle working fluid, converting the gaseous organic working fluid into a liquid organic working fluid. The saturated liquid working fluid is compressed approximately isentropically in the pump, becoming a low-temperature, high-pressure liquid working fluid. This liquid working fluid is then injected into the gas heating and heat exchange device 16 by pump 17, absorbing heat under high pressure to become a high-temperature, high-pressure steam working fluid. This steam then enters the turbine 15, undergoing isentropic expansion, driving the turbine blades to rotate and powering the generator 13 to generate electricity. The electrical energy is stored in the power management unit 14 for system use or external transmission. The steam working fluid, after its work, is introduced into the condenser 18, where it exchanges heat with the low-temperature natural gas, achieving isobaric heat release, and is then re-condensed into a low-temperature, low-pressure saturated liquid working fluid, entering the next cycle.

[0022] The gas-liquid mixture discharged from the wet gas outlet of the supersonic separator is separated into gas and liquid components by gas-liquid separator 7. The mixture is then pressurized by compressor 10 and stored in pressure regulating tank 20. When the front-end pressure sensor 2 detects a decrease in the turbine expander inlet pressure, pressure regulating valve 11 is opened, allowing the pressurized waste gas stored in pressure regulating tank 20 to be recirculated and combined with the inlet source gas, increasing the turbine expander inlet pressure to the set value. This not only improves the component removal efficiency of natural gas but also ensures reliable system operation. Gas-liquid separator 7 is equipped with a drain port to discharge the separated material for further processing.

[0023] based on Evaluation methods were established, such as Figure 2 The natural gas component removal process system combining TTPES and ORC shown is Analysis model, through Overall evaluation of the process system loss.

[0024] Gravity settling separator 3 The analysis model is shown in equation (1):

[0025] E i3 =E loss3 +E o3 +E s3 (1)

[0026] Among them, E i3 Indicates the inlet of gravity settling separator 3 E o3 and E s3 For the outlet of gravity settling separator 3 E loss3 For gravity settling separator 3 loss.

[0027] Heat exchanger 4 The analytical model is shown in equation (2):

[0028] E i4 =E o9 +E o3 =E loss4 +E o4 +E x4 (2)

[0029] Among them, E i4 Indicates the inlet of heat exchanger 4 E o4 and E x4 For the outlet of gravity heat exchanger 4 E loss4 For heat exchanger 4 Loss, E o9 For valve 9 outlet The value is 0 when valve 9 is closed, and E when valve 9 is open and valve 8 is closed. o6 .

[0030] Turbine expander 5 The analytical model is shown in equation (3):

[0031] E i5 =E o4 +E o10 =E loss5 +E o5 +W5 (3)

[0032] Among them, E i5 Indicates the inlet of turbine expander 5 E o5 For the outlet of turbine expander 5 E loss5 For turbine expander 5 Loss, W5 is the mechanical energy generated by expander 5.

[0033] Supersonic Separator 6 The analytical model is shown in equation (4):

[0034] E i6 =E o5 =E loss6 +E o6 +E x6 (4)

[0035] Among them, E i6 Indicates the inlet of supersonic separator 6 E o6 and E x6 For the outlet of supersonic separator 6 E loss6 For the supersonic separator 6 loss.

[0036] Gas-liquid separator 7 The analytical model is shown in equation (5):

[0037] E i7 =E x6 =E loss7 +E o7 +E s7 (5)

[0038] Among them, E i7 Indicates the inlet of gas-liquid separator 7 E o7 and E s7 For the outlet of gas-liquid separator 7 E loss7 For gas-liquid separator 7 loss.

[0039] Compressor 10 The analytical model is shown in equation (6):

[0040] E i10 =E o7 +E e10 =E loss10 +E o10 (6)

[0041] Among them, E i10 Indicates the inlet of compressor 10 E o10 For the outlet of compressor 10 E loss10 For compressor 10 Loss, E e10 The compressor consumes electricity

[0042] Membrane separator 12 The analytical model is shown in equation (7):

[0043] E i12 =E o18 +E x4 =E loss12 +E o12 +E s12 (7) Among them, E i12 Indicates the inlet of membrane separator 12 E o12 and E s12 For the outlet of membrane separator 12 E loss12 For membrane separator 12 loss.

[0044] Generator 13 The analytical model is shown in equation (8):

[0045] E i13 =W5+W 15 =E loss13 +E oe13 (8)

[0046] Among them, E i13 Indicates the inlet of generator 13 E oe13 The electricity generated by generator 13 E loss13 For generator 13 loss.

[0047] Steam Turbine 15 The analytical model is shown in equation (9):

[0048] E i15 =E o16 =E loss15 +E o15 +W 15 (9)

[0049] Among them, E i15 Indicates the inlet of steam turbine 15 E o15 For the outlet of steam turbine 15 E loss15 For steam turbine 15 Loss, W 15 Mechanical energy generated by steam turbine 15

[0050] Gas heating and heat exchange device 16 The analytical model is shown in equation (10):

[0051] E i16 =E o17 +E o19 =E loss16 +E o16 +E s16 (10)

[0052] Among them, E i16 Indicates the inlet of the gas heating and heat exchange device 16 E o16 and E s16 For the outlet of the gas heating and heat exchange device 16 E loss16 For gas heating and heat exchange device 1 Loss, E o19 Natural gas fuel consumed by heating devices

[0053] Pump 17 The analytical model is shown in equation (11):

[0054] E i17 =E e17 +E x18 =E loss17 +E o17 (11)

[0055] Among them, E i17 Indicates the inlet of pump 17 E o17 For the outlet of pump 17 E loss17 For pump 17 Loss, E e17 The pump consumes electricity

[0056] Heat exchanger 18 The analytical model is shown in equation (12):

[0057] E i18 =E o8 +E o15 =E loss18 +E o18 +E x18 (12)

[0058] Among them, E i4 Indicates the inlet of heat exchanger 18 E o4 and E x4 For the outlet of gravity heat exchanger 18 E loss4 For heat exchanger 18 Loss, E o8 For valve 8 outlet The value is 0 when valve 8 is closed, and E when valve 8 is open and valve 9 is closed. o6 .

[0059] The system's total Loss is:

[0060] E loss =E loss3 +E loss4 +E loss5 +E loss6 +E loss7 +E loss10 +E loss12 +E loss13 +E loss15 +E loss16 +E loss17 +E loss18 .

Claims

1. A natural gas component removal process system combining TTPES and ORC, comprising: a source gas pretreatment unit, a TTPES natural gas component removal and pressure energy recovery unit, an ORC cold energy recovery unit, a waste gas recirculation and pressure regulation unit, and an energy management unit, characterized in that, The TTPES (Total Pressure Recovery and Utilization System) natural gas component removal and pressure energy recovery unit includes a heat exchanger, a turbo expander, a supersonic separator, a generator, and an energy management unit. High-pressure natural gas, processed by the source gas pretreatment unit, is fed into the turbo expander via the heat exchanger, driving the generator to convert pressure energy into electrical energy, which is then stored and utilized through the energy management unit. Natural gas, with reduced pressure and temperature after passing through the turbo expander, is further processed in the supersonic separator. The low-temperature natural gas, after condensation and separation in the supersonic separator, is processed by the ORC (Organic Energy Recovery and Utilization) cold energy recovery unit. Exhaust gas discharged from the wet gas outlet of the supersonic separator is fed into the exhaust gas recirculation and pressure regulation unit. This unit includes a gas-liquid separator, a compressor, and a pressure regulating valve. The exhaust gas obtained from the supersonic separator is fed into the gas-liquid separator for secondary processing. The compressor then recirculates the secondary-processed exhaust gas back to the inlet of the turbo expander to merge with the heat-exchanged natural gas. The pressure regulating valve controls and stabilizes the source gas pressure at the turbo expander inlet.

2. The natural gas component removal process system according to claim 1, characterized in that, The ORC cold energy recovery and utilization unit includes a cryogenic condenser, a pump, a steam turbine, a gas heating and heat exchange device, a generator, and an energy management unit. The gas heating and heat exchange device generates heat from the natural gas processed by the combustion process system, and the generated heat provides a heat source for the ORC cycle working fluid. The cryogenic natural gas at the outlet of the supersonic separator provides a cold source for the ORC cycle. After the cryogenic condenser recovers and utilizes the cold energy, the steam turbine drives the generator to convert the pressure energy into electrical energy, which is then stored and utilized through the energy management unit.

3. The natural gas component removal process system according to claim 1, characterized in that, After being condensed and separated by the supersonic separator, part of the low-temperature natural gas is recycled to the front-end heat exchanger for inlet heat exchange.

4. The natural gas component removal process system according to claim 1, characterized in that, The source gas pretreatment unit includes a gravity settling separator, through which some liquid moisture and solid particulate matter components are removed from the high-pressure natural gas source gas.

5. The natural gas component removal process system according to claim 1, characterized in that, It also includes a membrane separation deep purification unit, which includes a membrane separator and a gas transmission pipeline. The low-temperature natural gas, after being condensed and separated by the supersonic separator, is then used by the low-temperature condenser of the inlet heat exchange or ORC cold energy recovery and utilization unit before being introduced into the membrane separator to achieve deep purification of the natural gas and obtain pure natural gas for gathering and transportation.

6. The natural gas component removal process system according to claim 5, characterized in that, Part of the pure natural gas obtained after the membrane separation deep purification unit is fed into the gas heating and heat exchange device in the ORC cycle for use, providing the required heat energy for the ORC cycle.

7. The natural gas component removal process system according to claim 1, characterized in that, The electrical energy obtained from the generator is stored in the power management unit to provide power to the power-consuming units within the process system.

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