Gas turbine combustion system based on membrane separation tail gas recycling

Abstract

The utility model provides a gas turbine combustion system based on membrane separation tail gas recycling, which belongs to the technical field of gas turbine fuel mixing and comprises a first branch, a second branch, a third branch, a fourth branch, a first trunk and a second trunk. The inlet end of the first branch is connected with a natural gas source, and the inlet end of the second branch is connected with a synthesis gas source; the second trunk comprises a membrane tail gas separation device which is connected with the refining device, the outlet end of the second trunk is connected with a third branch and a fourth branch which are connected in parallel, the outlet end of the third branch is connected with the inlet end of the first trunk, and the outlet end of the fourth branch and the outlet end of the first trunk are connected with the gas turbine. The system can be switched among natural gas, mixed gas of natural gas and synthesis gas and membrane separation tail gas according to the actual production condition of a refinery enterprise, so that the fuel cost of a power plant is reduced, and the economic benefit is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of fuel blending of gas turbines, and particularly relates to a gas turbine combustion system based on membrane separation tail gas recovery and utilization. Background Technique

[0002] A gas turbine is an internal combustion power machine that uses continuously flowing gas as the working medium to drive the impeller to rotate at high speed and convert the energy of fuel into useful work. Gas turbine power generation has been widely used in power plants at home and abroad, and the level of fuel cost determines the profitability of gas turbine power stations.

[0003] At present, in some refining enterprises, the fuels of gas turbine power stations mainly include natural gas with a single working medium, hydrogen-rich syngas, and a mixture of the two. However, the cost is still high during actual operation. The tail gas generated by refining units can be separated by a membrane separation device into fuels suitable for gas turbines, and this fuel is called membrane separation tail gas. Since the membrane separation tail gas is the waste gas in the chemical production process, the cost is very low. If the membrane separation tail gas is utilized, the economic benefits of gas turbine power stations can be significantly improved. Content of the Utility Model

[0004] Aiming at the problems existing in the above-mentioned prior art, the utility model provides a gas turbine combustion system based on membrane separation tail gas recovery and utilization. The technical problem to be solved by the utility model is how to reduce the fuel cost of power plants and improve economic benefits.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A gas turbine combustion system based on membrane separation tail gas recovery and utilization includes: a first branch, a second branch, a third branch, a fourth branch, a first main line, and a second main line. The first branch and the second branch are connected in parallel and merge into the first main line. The inlet end of the first branch is connected to a natural gas source, and the inlet end of the second branch is connected to a syngas source; the second main line includes a membrane tail gas separation device, the membrane tail gas separation device is connected to a refining unit, the outlet end of the second main line is connected to the third branch and the fourth branch, the third branch and the fourth branch are connected in parallel with each other, the outlet end of the third branch is connected to the inlet end of the first main line, and the outlet end of the fourth branch and the outlet end of the first main line are connected to a gas turbine.

[0007] Furthermore, control valves are installed on the first branch, the second branch, the third branch, the fourth branch, the first main line, and the second main line.

[0008] Further, the first branch includes a first control valve, a first filtration unit, a first metering unit, a first on-line chromatograph, and a first heating unit connected in sequence. The first control valve is connected to the natural gas source, and the first heating unit is connected to the inlet end of the first main line.

[0009] Further, the second branch includes a second control valve, a second filtration unit, a first pressure regulating unit, and a second on-line chromatograph connected in sequence. The second control valve is connected to the syngas source, and the second on-line chromatograph is connected to the inlet end of the first main line.

[0010] Further, the first main line includes a static mixer, a buffer tank, a first rapid calorimeter, and a second pressure regulating unit connected in sequence. The static mixer is connected to the outlet ends of the first branch and the second branch, and the second pressure regulating unit is connected to the gas turbine.

[0011] Further, the second main line includes the membrane tail gas separation device, a third filtration unit, a third pressure regulating unit, and a third on-line chromatograph connected in sequence. The third on-line chromatograph is connected to the third branch and the fourth branch.

[0012] Further, a third control valve is provided in the third branch. The third control valve is respectively connected to the third on-line chromatograph and the inlet end of the first main line.

[0013] Further, the fourth branch includes a second rapid calorimeter and a fourth control valve connected in sequence. The second rapid calorimeter is connected to the third on-line chromatograph, and the fourth control valve is connected to the gas turbine.

[0014] Further, a fifth control valve is also provided between the membrane tail gas separation device and the refining device.

[0015] Further, a three-way valve is provided between the third on-line chromatograph and the third branch and the fourth branch. The inlet of the three-way valve is connected to the third on-line chromatograph, and the two outlets of the three-way valve are respectively connected to the third branch and the fourth branch.

[0016] The working principle of the present utility model is as follows:

[0017] Natural gas passes through the first branch, and syngas passes through the second branch and converges into the first main line. After the natural gas and the syngas are mixed by the static mixer, they become fuels meeting the requirements of the gas turbine and are transported to the gas turbine.

[0018] The refining unit generates a large amount of combustible gas. After passing through the membrane separation unit, the generated membrane tail gas has good combustion performance. When the composition of the membrane tail gas changes greatly, it can enter the static mixer through the third branch. After mixing with natural gas, it is transported to the gas turbine as fuel through the first main road; when the composition of the membrane tail gas is stable and the Wobbe index meets the requirements for direct combustion of the gas turbine, it can also be directly transported to the gas turbine as fuel through the fourth branch.

[0019] Compared with the prior art, the present utility model has the following beneficial effects:

[0020] 1. This fuel system can switch among natural gas, the mixture of natural gas and syngas, and membrane separation tail gas according to the actual production situation of the refining enterprise and the costs of natural gas, syngas, and membrane separation tail gas, thereby further reducing the fuel cost of the power plant and improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0022] In the figure:

[0023] 1 - natural gas gas source, 2 - syngas gas source, 3 - membrane tail gas separation unit, 4 - refining unit, 5 - gas turbine, 6 - first control valve, 7 - first filtration unit, 8 - first metering unit, 9 - first on-line chromatograph, 10 - first heating unit, 11 - second control valve, 12 - second filtration unit, 13 - first pressure regulating unit, 14 - second on-line chromatograph, 15 - static mixer, 16 - buffer tank, 17 - first rapid calorimeter, 18 - second pressure regulating unit, 19 - third filtration unit, 20 - third pressure regulating unit, 21 - third on-line chromatograph, 22 - third control valve, 23 - second rapid calorimeter, 24 - fourth control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Next, in conjunction with the drawings, the technical solutions of the present utility model will be described clearly and completely.

[0025] Embodiment 1

[0026] As shown in the Figure 1 drawing, the following technical solutions are provided in this embodiment:

[0027] A gas turbine combustion system based on membrane separation tail gas recovery and utilization, comprising: a first branch, a second branch, a third branch, a fourth branch, a first main line and a second main line. The first branch and the second branch are connected in parallel and merge into the first main line. The inlet end of the first branch is connected to a natural gas source 1, and the inlet end of the second branch is connected to a syngas source 2. The second main line includes a membrane tail gas separation device 3, which is connected to a refining device 4, and the outlet end is connected to the third branch and the fourth branch. The third branch and the fourth branch are connected in parallel with each other. The outlet end of the third branch is connected to the inlet end of the first main line, and the outlet end of the fourth branch and the outlet end of the first main line are connected to a gas turbine 5.

[0028] Further, control valves are installed on the first branch, the second branch, the third branch, the fourth branch, the first main line and the second main line.

[0029] Further, the first branch includes a first control valve 6, a first filtration unit 7, a first metering unit 8, a first on-line chromatograph 9, and a first heating unit 10 connected in sequence. The first control valve 6 is connected to the natural gas source 1, and the first heating unit 10 is connected to the inlet end of the first main line.

[0030] Further, the second branch includes a second control valve 11, a second filtration unit 12, a first pressure regulating unit 13, and a second on-line chromatograph 14 connected in sequence. The second control valve 11 is connected to the syngas source 2, and the second on-line chromatograph 14 is connected to the inlet end of the first main line.

[0031] Further, the first main line includes a static mixer 15, a buffer tank 16, a first rapid calorimeter 17, and a second pressure regulating unit 18 connected in sequence. The static mixer 15 is connected to the outlet end of the first branch and the outlet end of the second branch, and the second pressure regulating unit 18 is connected to the gas turbine 5.

[0032] Further, the second main line includes the membrane tail gas separation device 3, a third filtration unit 19, a third pressure regulating unit 20, and a third on-line chromatograph 21 connected in sequence. The third on-line chromatograph 21 is connected to the third branch and the fourth branch.

[0033] Further, the third branch is provided with a third control valve 22, and the third control valve 22 is respectively connected to the third on-line chromatograph 21 and the inlet end of the first main line.

[0034] Further, the fourth branch includes a second rapid calorimeter 23 and a fourth control valve 24 connected in sequence. The second rapid calorimeter 23 is connected to the third on-line chromatograph 21, and the fourth control valve 24 is connected to the gas turbine 5.

[0035] Further, a fifth control valve is also provided between the membrane tail gas separation device 3 and the refining device 4.

[0036] The working principle of this embodiment is as follows:

[0037] The refining device 4 generates a large amount of combustible gas. After passing through the membrane tail gas separation device 3, combustible tail gas with the components shown in Table 1 can be generated, in which methane accounts for about 75% and hydrogen accounts for about 13%. The combustible tail gas generated by the membrane separation device has a temperature of about 15°C and a pressure of about 25 bar, which is an ideal fuel for a gas turbine. After being transported through a pipeline, the membrane tail gas can be transported to the third filtration unit 19. In the third filtration unit 19, the membrane tail gas undergoes further dehydration and impurity removal, and the output clean gas is input to the third pressure regulating unit 20. The pressure-regulated membrane tail gas finally enters the pre-module of the gas turbine 5 and is utilized by the gas turbine 5 to generate electric energy and steam.

[0038] Table 1: Components of the membrane separation tail gas

[0039]

[0040]

[0041] The static mixer 15 in the first main path is a mixing device that can mix natural gas and syngas. The mixed gas undergoes buffering and pressure regulation and is then transported as fuel to the inlet of the pre-module of the gas turbine 5, and then is utilized by the gas turbine.

[0042] The switching between the membrane tail gas and the mixed gas is controlled by the flow control valves of the four branches.

[0043] 1. When the components of the membrane tail gas are stable and the Wobbe number meets the requirements for direct combustion of the gas turbine, it can be directly transported through the fourth branch to the gas turbine 5 as fuel. This mode can be further divided into two cases:

[0044] 1) When the syngas is relatively abundant and the membrane tail gas has other uses, the control valves of the third and fourth branches are closed. The gas turbine 5 burns the mixed gas of syngas and natural gas.

[0045] 2) When the membrane tail gas is relatively abundant, the control valve of the second branch is always closed, that is, no syngas is used, and natural gas is only used in a small amount during startup. After the load of the gas turbine reaches 50%, the control valve of the first branch is slowly closed, and the fourth branch is opened. The gas turbine 5 continues to operate with the membrane tail gas as fuel.

[0046] 2. When the components of the tail gas generated by the membrane tail gas separation device 3 are adjustable or the components of the tail gas are unstable, it will cause a large fluctuation in the combustible gas components of the tail gas. At this time, after the membrane tail gas is transported through the pipeline, it is transported to the third filtration unit 19. In the third filtration unit 19, the membrane tail gas is further dehydrated and desulfurized, and the output clean gas is input to the third pressure regulating unit 20. The fourth branch is closed, and the pressure-regulated membrane tail gas can enter the first main road through the third branch. After being mixed with natural gas in the static mixer 15, it is transported to the gas turbine 5 as fuel through the first main road. This mode can also be divided into two cases:

[0047] 1) When the syngas is relatively rich and the membrane tail gas has other uses, the control valve of the third branch is closed, and the gas turbine 5 burns the mixture of syngas and natural gas;

[0048] 2) When the membrane tail gas is relatively rich. The control valve of the second branch is closed, and the gas turbine 5 burns the mixture of membrane tail gas and natural gas.

[0049] Embodiment 2

[0050] The difference from Embodiment 1 is that in this embodiment, a three-way valve is provided between the second main road, the third branch, and the fourth branch. The inlet of the three-way valve is connected to the outlet end of the second main road, and the two outlets of the three-way valve are respectively connected to the third branch and the fourth branch.

[0051] It can be switched between the third branch and the fourth branch by adjusting the three-way valve. When the components of the membrane tail gas are stable, the membrane tail gas is directly transported to the gas turbine 5 as fuel through the fourth branch; when the components of the tail gas generated by the membrane tail gas separation device 3 are adjustable or the components of the tail gas are unstable, the membrane tail gas can enter the first main road through the third branch. After being mixed with natural gas in the static mixer 15, it is transported to the gas turbine 5 as fuel through the first main road.

[0052] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A gas turbine combustion system based on membrane separation tail gas recovery and utilization, characterized in that: include: A first branch, a second branch, a third branch, a fourth branch, a first trunk and a second trunk, the first branch and the second branch are connected in parallel and merge into the first trunk, the inlet end of the first branch is connected to a natural gas source, and the inlet end of the second branch is connected to a synthesis gas source; the second trunk includes a membrane tail gas separation device, and the membrane tail gas separation device is connected to a refining device, the outlet end of the second trunk is connected to the third branch and the fourth branch, the third branch and the fourth branch are connected in parallel with each other, the outlet end of the third branch is connected to the inlet end of the first trunk, and the outlet end of the fourth branch and the outlet end of the first trunk are connected to a gas turbine.

2. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 1, characterized in that: The first branch, the second branch, the third branch, the fourth branch, the first trunk and the second trunk are all equipped with control valves.

3. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 1, characterized in that: The first branch includes a first control valve, a first filtering unit, a first metering unit, a first online chromatograph, and a first heating unit which are connected in sequence. The first control valve is connected to a natural gas source, and the first heating unit is connected to an inlet end of the first trunk line.

4. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 1, characterized in that: The second branch includes a second control valve, a second filtering unit, a first pressure regulating unit, and a second online chromatograph which are connected in sequence. The second control valve is connected to a synthesis gas source, and the second online chromatograph is connected to an inlet end of the first trunk.

5. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 1, characterized in that: The first trunk line includes a static mixer, a buffer tank, a first rapid calorific value meter, and a second pressure regulating unit which are connected in sequence. The static mixer is connected to the outlet end of the first branch line and the outlet end of the second branch line, and the second pressure regulating unit is connected to the gas turbine.

6. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 1, characterized in that: The second trunk line includes the membrane tail gas separation device, the third filtering unit, the third pressure regulating unit, and the third online chromatograph which are connected in sequence, and the third online chromatograph is connected to the third branch line and the fourth branch line.

7. The gas turbine combustion system based on membrane separation tail gas recovery and utilization as claimed in claim 6, characterized in that: The third branch is provided with a third control valve, and the third control valve is respectively connected to the third online chromatograph and the inlet end of the first trunk.

8. The gas turbine combustion system based on membrane separation tail gas recovery and utilization as claimed in claim 6, characterized in that: The fourth branch includes a second rapid calorific value meter and a fourth control valve which are connected in sequence, the second rapid calorific value meter is connected to a third online chromatograph, and the fourth control valve is connected to a gas turbine.

9. The gas turbine combustion system based on membrane separation tail gas recovery and utilization as claimed in claim 6, characterized in that: A fifth control valve is also arranged between the membrane tail gas separation device and the refining device.

10. The gas turbine combustion system based on membrane separation tail gas recovery and utilization according to claim 6, characterized in that: A three-way valve is arranged between the second trunk and the third branch and the fourth branch, the inlet of the three-way valve is connected to the third online chromatograph, and the two outlets of the three-way valve are connected to the third branch and the fourth branch respectively.

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