Improved coal supercritical water gasification power generation dual-circulation system

Abstract

The utility model discloses an improved coal supercritical water gasification power generation double-circulation system, which relates to the field of high-temperature and high-pressure mixed medium power generation and comprises an energy release system, the energy release system is connected with a mixed turbine generator set, a medium outlet of the mixed turbine generator set is connected with a step-by-step heat exchange system, and the step-by-step heat exchange system is connected with a power supply system. The step-by-step heat exchange system comprises a low-temperature water outlet, a low-temperature gas outlet, a low-temperature water inlet and a high-temperature outlet communicated with the low-temperature water inlet, and the high-temperature outlet is connected to the steam turbine generator set through the energy release system; the low-temperature water outlet is connected with a dissolved gas releasing device, and a gas outlet of the dissolved gas releasing device and the low-temperature gas outlet are jointly connected to an inlet of the condensation tank. The device can effectively improve the purity of carbon dioxide in tail gas of a system, increase the capture amount of the carbon dioxide, increase the utilization rate of the carbon dioxide of the system, reduce the acidity of condensate water and slow down equipment corrosion.

Description

Technical Field

[0001] The utility model relates to the field of high-temperature and high-pressure mixed medium power generation, in particular to an improved coal supercritical water gasification power generation double circulation system. Background Art

[0002] The supercritical water gasification combustion power generation system is a technology that uses water as a medium to couple coal gasification with hydrogen production and power generation. It uses the unique physical and chemical properties of supercritical water (pressure higher than 22.1MPa, temperature higher than 374.3℃) such as high solubility and high diffusivity to promote coal gasification reactions and generate a mixed gas mainly composed of hydrogen (H2) and carbon monoxide (CO), while elements such as N and S are fixed in the water-insoluble inorganic salts produced by the reaction, and are eventually discharged as solid residues, which is clean and environmentally friendly.

[0003] At present, the new generation of coal supercritical water gasification power generation system, such as the Chinese utility model patent with application number "2022230751813", discloses "A dual-cycle power generation system suitable for high-temperature and high-pressure mixed working fluids", which oxidizes and burns the generated mixed gas to produce a mixed gas of high calorific value water vapor (H2O(g)) and carbon dioxide (CO2), which drives the mixed working fluid turbine to generate power. The exhaust gas after power generation is cooled and condensed by a heat exchanger, and liquid water is separated to obtain carbon dioxide; at the same time, the feed water uses the heat exchanger to absorb the heat of the exhaust gas to form high calorific value steam, which drives the steam turbine to generate electricity and provides the high-temperature water required for coal gasification; the power generation system generates electricity through mixed working fluids, and the heat energy of the exhaust gas of the mixed working fluid power generation unit is recycled and utilized through a step-by-step heat exchange system to promote steam power generation, increase the power generation per unit raw material, and improve energy utilization efficiency.

[0004] The liquid water in the mixed working fluid at the outlet of the heat exchanger of this power generation system has a large amount of carbon dioxide dissolved in it due to high pressure, which not only reduces the amount of carbon dioxide that can be stored and utilized by the subsequent system, but also increases the acidity of the water, increasing the risk of equipment corrosion. Therefore, based on this system, in order to further improve the quality of carbon dioxide in the tail gas, increase the carbon dioxide capture and utilization rate of the system, and reduce the acidity of the condensed water, an improved coal supercritical water gasification power generation double circulation system is proposed. Utility Model Content

[0005] The purpose of the utility model is to provide an improved coal supercritical water gasification power generation dual circulation system in response to the above-mentioned problems, which can effectively improve the purity of carbon dioxide in the system exhaust gas, increase the amount of carbon dioxide captured, increase the utilization rate of carbon dioxide in the system, reduce the acidity of condensed water, and slow down equipment corrosion.

[0006] The technical solution adopted by the utility model is as follows: an improved coal supercritical water gasification power generation dual circulation system, including an energy release system capable of generating high-temperature and high-pressure water vapor and carbon dioxide, the mixed working fluid outlet of the energy release system is connected to a mixed turbine generator set, the medium outlet of the mixed turbine generator set is connected to the high-temperature gas inlet of a step-by-step heat exchange system so that the mixed working fluid enters the step-by-step heat exchange system, the step-by-step heat exchange system has a low-temperature water outlet for flowing out liquid water formed by condensation of the mixed working fluid in the step-by-step heat exchange system, and a low-temperature gas outlet for flowing out gaseous working fluid remaining after the mixed working fluid passes through the step-by-step heat exchange system; the step-by-step heat exchange system also has a low-temperature water inlet for entering low-temperature liquid water and a high-temperature water outlet connected to the low-temperature water inlet, the high-temperature water outlet is connected to the steam turbine generator set through the energy release system; the low-temperature water outlet is connected to a dissolved gas release device, and the gas outlet of the dissolved gas release device and the low-temperature gas outlet are commonly connected to the inlet of a condensation tank.

[0007] Furthermore, the water outlet of the dissolved gas release device, the water outlet of the condensation tank and the low-temperature water inlet are all connected to the water treatment system to realize water circulation.

[0008] Furthermore, the steam medium outlet of the steam turbine generator set is connected to the water treatment system through a condenser.

[0009] Furthermore, a medium-pressure pump is arranged between the condenser and the water treatment system.

[0010] Furthermore, the water treatment system is provided with a drain outlet.

[0011] Furthermore, the step-by-step heat exchange system includes a plurality of heat exchanger groups connected in series, the high-temperature gas inlet and the high-temperature water outlet are arranged on the first heat exchanger group, and the low-temperature water outlet and the low-temperature water inlet are arranged on the last heat exchanger group.

[0012] Furthermore, the energy release system includes a water-coal reactor and a burner, the gas outlet of the water-coal reactor is connected to the gas inlet of the burner, and the mixed working medium outlet is arranged on the burner.

[0013] Furthermore, a bypass is provided between the high-temperature water outlet and the low-temperature water inlet, and the bypass is connected to the liquid filling port of the water-coal reactor.

[0014] Furthermore, the bypass is connected to the water-coal reactor after heat exchange through the burner.

[0015] Furthermore, a high-pressure pump is provided on the bypass.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0017] 1. The utility model can increase the power generation per unit of raw materials and improve the thermoelectric conversion efficiency. On the basis of high-temperature and high-pressure mixed working fluid driving the hybrid turbine generator set, a step-by-step heat exchange system is used to convert the waste heat of the mixed working fluid after being used by the hybrid turbine generator set and the heat generated by the burner combustion into water vapor, and the steam turbine generator set is driven by the water vapor to increase the power generation per unit of raw materials and improve the thermoelectric conversion efficiency.

[0018] 2. The utility model captures a large amount of carbon dioxide. The dissolved carbon dioxide in the water (formed by condensation of water vapor in the mixed working fluid after heat exchange) cooled by the step-by-step heat exchange system is released and collected through the dissolved gas release device, which effectively increases the capture amount of carbon dioxide, reduces the amount of carbon dioxide dissolved in water, increases the utilization rate of carbon dioxide in the system, reduces the acidity of condensed water, and slows down equipment corrosion;

[0019] 3. The carbon dioxide produced by the utility model has high purity. On the one hand, the temperature of the mixed working medium is reduced after passing through the step-by-step heat exchange system, so that the water vapor in the mixed working medium is condensed, and finally high-purity carbon dioxide remains; on the other hand, the condensation tank is used to continue to condense the carbon dioxide gas flowing out of the low-temperature gas outlet and the gas outlet of the dissolved gas release device, so as to condense the water vapor entrained in the carbon dioxide gas, so as to obtain high-purity carbon dioxide, and create good conditions for the storage and utilization of carbon dioxide;

[0020] 4. The hybrid turbine generator set used in the utility model has no corrosion risk. Since the subsequent step-by-step heat exchange system can make full use of the waste heat and adjust the parameters of the hybrid turbine generator set, the mixed working medium can be kept in the hybrid turbine generator set in an overheated state, and there is no condensation of water vapor, thereby avoiding the acid corrosion of the hybrid turbine generator set by liquid water combined with carbon dioxide, ensuring the service life of the hybrid turbine generator set and reducing its material cost;

[0021] 5. The entire system consists of a coupled mixed working fluid cycle and a water vapor cycle. The system outputs electricity and carbon dioxide. It is a closed cycle for water, which saves water resources to the maximum extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described by way of examples with reference to the accompanying drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of the utility model;

[0024] Markings in the figure: 1-energy release system; 11-water-coal reactor; 12-burner; 13-mixed working fluid outlet; 2-mixed turbine generator set; 3-step-by-step heat exchange system; 31-high-temperature heat exchanger group; 32-low-temperature heat exchanger group; 33-high-temperature gas inlet; 34-high-temperature water outlet; 35-low-temperature gas outlet; 36-low-temperature water outlet; 37-low-temperature water inlet; 4-dissolved gas release device; 5-condensate tank; 6-water treatment system; 7-steam turbine generator; 8-condenser; 9-medium-pressure pump; 10-bypass; 101-high-pressure pump. DETAILED DESCRIPTION

[0025] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0026] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0027] Example 1

[0028] like Figure 1 As shown, an improved coal supercritical water gasification power generation dual circulation system includes an energy release system 1 capable of generating high-temperature and high-pressure water vapor and carbon dioxide. The energy release system 1 releases energy to provide energy for the entire dual power generation circulation system. The water vapor and carbon dioxide form a mixed working fluid. The mixed working fluid outlet 13 of the energy release system 1 is connected to a hybrid turbine generator set 2. The high-temperature and high-pressure mixed working fluid flows out from the mixed working fluid outlet 13 and enters the hybrid turbine generator set 2, driving the hybrid turbine generator set 2 to generate electricity, thereby realizing the first power generation utilization of the energy released by the energy release system 1.

[0029] In this embodiment, the medium outlet of the hybrid turbine generator set 2 is connected to the high-temperature gas inlet 33 of the step-by-step heat exchange system 3 so that the mixed working medium enters the step-by-step heat exchange system 3, and the mixed working medium flowing out of the hybrid turbine generator set 2 undergoes heat exchange in the step-by-step heat exchange system to achieve waste heat recovery; the step-by-step heat exchange system 3 has a low-temperature water outlet 36, and the low-temperature water outlet is used to flow out the liquid water formed by condensation of water vapor in the mixed working medium during the heat exchange process in the step-by-step heat exchange system 3; the step-by-step heat exchange system 3 has a low-temperature gas outlet 35, and the low-temperature gas outlet 35 is used to flow out the gas working medium remaining after the mixed working medium passes through the step-by-step heat exchange system 3, and the gas working medium mainly consists of carbon dioxide and a small amount of water vapor entrained by carbon dioxide; the step-by-step heat exchange system 3 also has a low-temperature water inlet 37 for entering low-temperature liquid water and a high-temperature water outlet 34 connected to the low-temperature water inlet 37, and the high-temperature water outlet Port 34 is connected to steam turbine generator set 7 through energy release system 1; specifically, after the high-temperature and high-pressure mixed working fluid passes through the mixed turbine generator set 2 to utilize part of its energy, the mixed working fluid has a large amount of energy and flows out of the mixed turbine generator set 2 from the medium outlet, and then flows into the step-by-step heat exchange system 3 from the high-temperature gas inlet 33. After the mixed working fluid flows into the step-by-step heat exchange system 3, it exchanges heat with liquid water that flows into the step-by-step heat exchange system 3 from the low-temperature water inlet 37, and recovers the waste heat in the mixed working fluid to form a high-temperature water medium. According to the state of the water after the heat exchange, it can be liquid water, steam, or a mixture of liquid water and steam. The high-temperature water medium flows out from the high-temperature water outlet 34 into the energy release system 1, obtains energy in the energy release system 1 to form water vapor, and then flows out into the steam turbine generator set 7 for the second power generation, thereby increasing the power generation per unit raw material and improving the thermoelectric conversion efficiency.

[0030] In this embodiment, the low-temperature water outlet 36 is connected to the dissolved gas release device 4. The water vapor in the mixed working medium is condensed into liquid water after heat exchange through the step-by-step heat exchange system 3. Carbon dioxide is dissolved in the liquid water. After the liquid water flows out from the low-temperature water outlet 36, it enters the dissolved gas release device 4 and is depressurized and energy-dissipated, thereby releasing the dissolved carbon dioxide, effectively increasing the amount of carbon dioxide captured, reducing the amount of carbon dioxide dissolved in water, increasing the utilization rate of carbon dioxide in the system, reducing the acidity of condensed water, and slowing down equipment corrosion; the gas outlet of the dissolved gas release device 4 and the low-temperature gas outlet 35 are jointly connected to the inlet of the condensation tank 5, wherein the carbon dioxide flowing out of the gas outlet of the dissolved gas release device 4 is carbon dioxide dissolved in liquid water, and the carbon dioxide flowing out of the low-temperature gas outlet 35 is carbon dioxide dissolved in liquid water. The carbon dioxide is the residual carbon dioxide after the mixed working medium passes through the step-by-step heat exchange system 3. All carbon dioxide gases carry water vapor into the condenser 5, and the condenser 5 condenses the water vapor again to achieve the purpose of purifying carbon dioxide. In summary, the carbon dioxide captured by this system has high purity. On the one hand, the temperature of the mixed working medium decreases after passing through the step-by-step heat exchange system 3, so that the water vapor in the mixed working medium condenses, and finally high-purity carbon dioxide remains. On the other hand, the condenser 5 is used to continue to condense the carbon dioxide gas flowing out of the low-temperature gas outlet 35 and the gas outlet of the dissolved gas release device 4, so as to condense the water vapor entrained in the carbon dioxide gas, so as to achieve the purpose of obtaining high-purity carbon dioxide, and create good conditions for the storage and utilization of carbon dioxide.

[0031] It should be noted that in this embodiment, since the energy of the high-temperature and high-pressure mixed working fluid can still be utilized in the step-by-step heat exchange system 3, when the energy of the mixed medium is first utilized for power generation (the mixed working fluid drives the hybrid turbine generator set 2 to generate electricity), the relevant parameters of the hybrid turbine generator set 2 can be adjusted so that the mixed working fluid remains in an overheated state in the hybrid turbine generator set 2, that is, the mixed working fluid flowing out of the medium outlet of the hybrid turbine generator set 2 is in a gaseous state, and there is no condensation of water vapor, thereby avoiding acid corrosion of the hybrid turbine generator set 2 by liquid water combined with carbon dioxide, thereby ensuring the service life of the hybrid turbine generator set 2 and reducing its material cost.

[0032] Example 2

[0033] Based on Example 1, a specific implementation method that can be implemented is further proposed.

[0034] A feasible implementation method is that the water outlet of the dissolved gas release device 4 and the water outlet of the condensation tank 5 are connected to the water treatment system 6, and the water that has completed the release of carbon dioxide in the dissolved gas release device 4 and the water condensed from the condensation tank 5 enter the water treatment system 6, and the water treatment system 6 performs impurity removal, pressurization and other treatments on the liquid water; the low-temperature water inlet 37 is connected to the water treatment system 6, and the liquid water enters the step-by-step heat exchange system 3 from the low-temperature water inlet 37 after being treated by the water treatment system 6 to obtain the waste heat in the mixed working fluid, thereby realizing the recycling of water resources and achieving the purpose of avoiding waste of resources.

[0035] A feasible implementation method is that the steam medium outlet of the steam turbine generator group 7 is connected to the water treatment system 6 through the condenser 8; specifically, after the liquid water entering from the low-temperature water inlet 37 passes through the step-by-step heat exchange system 3 and the energy release system 1 to obtain heat energy, the liquid water undergoes a phase change to form water vapor, and the water vapor enters the steam turbine generator group 7 to drive the steam turbine generator group 7 to generate electricity, thereby realizing the second power generation utilization of the energy of the mixed working fluid; the steam turbine generator group 7 fully utilizes the energy of the steam, and the steam enters the condenser after passing through the steam turbine generator group 7 to be condensed into liquid water and enters the water treatment system 6 again, thereby further realizing the recycling of water resources and avoiding waste of resources.

[0036] In a feasible implementation manner, a medium-pressure pump 9 is provided between the condenser 8 and the water treatment system 6 to transport the liquid water condensed in the condenser 8 .

[0037] A feasible implementation method is that since the energy release system 1 will continuously generate water vapor, the water in the water treatment system 6 will increase, so the water treatment system 6 is provided with a drain outlet, which can discharge excess liquid water (the amount of liquid water not needed by the system).

[0038] Example 3

[0039] On the basis of any one of the implementations in Examples 1-2, a feasible implementation of the “step-by-step heat exchange system 3” is further proposed.

[0040] The step-by-step heat exchange system 3 includes a plurality of heat exchanger groups connected in series, and an example of two heat exchanger groups connected in series is used for description. The two heat exchanger groups are respectively a high-temperature heat exchanger group 31 and a low-temperature heat exchanger group 32. The high-temperature gas inlet 33 and the high-temperature water outlet 34 are arranged on the first heat exchanger group (high-temperature heat exchanger group 31), and the low-temperature gas outlet 35, the low-temperature water outlet 36 and the low-temperature water inlet 37 are arranged on the last heat exchanger group (low-temperature heat exchanger group 32). The mixed working fluid coming out of the hybrid turbine generator set 2 passes through the high-temperature gas inlet 33 and then passes through the high-temperature heat exchanger group 31 and the low-temperature heat exchanger group 32 successively. The liquid water entering from the low-temperature water inlet 37 passes through the low-temperature heat exchanger group 32 and the high-temperature heat exchanger group 31 successively, so as to realize convection heat exchange between the mixed working fluid and the liquid water, ensure that there is always a relatively suitable temperature difference between the mixed medium releasing energy and the liquid water absorbing energy, match the energy quality, so that each heat exchanger group can exchange heat between the mixed medium and the liquid water, and finally be heated by the energy release system 1 to form water vapor, and the water vapor drives the steam turbine generator 7 groups.

[0041] Example 4

[0042] Based on any one of the implementations in Examples 1-3, a feasible implementation is further proposed.

[0043] A feasible implementation manner, the energy release system 1 includes a water-coal reactor 11 and a burner 12, the water-coal reactor 11 can produce a "supercritical water boiling coal" reaction to generate clean combustible gases such as H2, CO2, CH4, etc., the gas outlet of the water-coal reactor 11 is connected to the gas inlet of the burner 12, the combustible gas enters the burner 12 through the gas outlet, and pure oxygen is supplied to the burner 12, so that the combustible gas burns to generate energy and forms a mixed working fluid of water vapor and carbon dioxide, the mixed working fluid outlet 13 is arranged on the burner 12, and the mixed working fluid enters the hybrid turbine generator set 2 from the mixed working fluid outlet 13 on the burner 12.

[0044] It should be noted that a large amount of heat in the burner 12 is taken out by the mixed medium, but there is still some heat in the burner 12. The high-temperature water outlet 34 is connected to the steam turbine generator 7 through the burner 12, and the high-temperature water medium passes through the burner 12 again to further obtain energy, thereby further increasing the temperature and pressure, and ensuring that the high-temperature water medium is completely converted into water vapor, so that the steam generator can increase its power generation, further utilize the energy in the energy release system 1, and further achieve the purpose of increasing the power generation per unit raw material and improving the thermoelectric conversion efficiency.

[0045] In this embodiment, a bypass 10 is provided between the high-temperature water outlet 34 and the low-temperature water inlet 37, and the liquid inlet of the bypass 10 is located between two adjacent heat exchanger groups. The bypass 10 is connected to the liquid filling port of the water-coal reactor 11, and water that meets the parameter requirements of the "supercritical water boiling coal" reaction carried out in the water-coal reactor 11 is introduced into the water-coal reactor 11 to participate in the "supercritical water boiling coal" reaction. On the one hand, the recycling of water is realized, and on the other hand, the "supercritical water boiling coal" reaction is ensured to continue, so that the energy release system 1 can continuously release energy.

[0046] Specifically, water between the high-temperature water outlet 34 and the low-temperature water inlet 37 is used (the state parameters of the water are determined according to the state of the water required by the water-coal reactor 11). Specifically, water that has undergone heat exchange in one or more heat exchanger groups is used, and the water has a relatively high temperature to ensure that the water added to the water-coal reactor 11 meets the state of the water required by the water-coal reactor 11, including temperature, pressure, phase state and other states. Here, the energy released by the energy release system 1 is further utilized to improve the energy utilization rate.

[0047] In this embodiment, a high-pressure pump 101 is provided on the bypass 10 for conveying water into the water-coal reactor 11 .

[0048] The present invention is not limited to the above-mentioned specific implementation modes, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. An improved coal supercritical water gasification power generation dual circulation system, comprising an energy release system (1) capable of generating high-temperature and high-pressure water vapor and carbon dioxide, wherein a mixed working medium outlet (13) of the energy release system (1) is connected to a mixed turbine generator set (2), and a medium outlet of the mixed turbine generator set (2) is connected to a high-temperature gas inlet (33) of a step-by-step heat exchange system (3) so that the mixed working medium enters the step-by-step heat exchange system (3), and the step-by-step heat exchange system (3) has a low-temperature water outlet (36) for flowing out liquid water formed by condensation of the mixed working medium in the step-by-step heat exchange system (3), and a low-temperature gas outlet (35) for flowing out gaseous working medium remaining after the mixed working medium passes through the step-by-step heat exchange system (3); the step-by-step heat exchange system (3) also has a low-temperature water inlet (37) for entering low-temperature liquid water and a high-temperature water outlet (34) connected to the low-temperature water inlet (37), and the high-temperature water outlet (34) is connected to a steam turbine generator set (7) through the energy release system (1); Features: The low-temperature water outlet (36) is connected to a dissolved gas release device (4), and the gas outlet of the dissolved gas release device (4) and the low-temperature gas outlet (35) are connected to the inlet of the condensation tank (5).

2. The improved coal supercritical water gasification power generation dual circulation system according to claim 1, Features: The water outlet of the dissolved gas release device (4), the water outlet of the condensation tank (5) and the low-temperature water inlet (37) are all connected to the water treatment system (6) to achieve water circulation.

3. The improved coal supercritical water gasification power generation dual circulation system according to claim 1, Features: The steam medium outlet of the steam turbine generator (7) group is connected to the water treatment system (6) through a condenser (8).

4. The improved coal supercritical water gasification power generation dual circulation system according to claim 3, Features: A medium-pressure pump (9) is provided between the condenser (8) and the water treatment system (6).

5. The improved coal supercritical water gasification power generation dual circulation system according to any one of claims 2 to 4, Features: The water treatment system (6) is provided with a drain outlet.

6. The improved coal supercritical water gasification power generation dual circulation system according to claim 1, Features: The step-by-step heat exchange system (3) comprises a plurality of heat exchanger groups connected in series, wherein the high-temperature gas inlet (33) and the high-temperature water outlet (34) are arranged on the first heat exchanger group, and the low-temperature water outlet (36) and the low-temperature water inlet (37) are arranged on the last heat exchanger group.

7. The improved coal supercritical water gasification power generation dual circulation system according to claim 1, Features: The energy release system (1) comprises a water-coal reactor (11) and a burner (12); the gas outlet of the water-coal reactor (11) is connected to the gas inlet of the burner (12); and the mixed working medium outlet (13) is arranged on the burner (12).

8. The improved coal supercritical water gasification power generation dual circulation system according to claim 7, Features: A bypass (10) is provided between the high-temperature water outlet (34) and the low-temperature water inlet (37), and the bypass (10) is connected to a liquid filling port of the water-coal reactor (11).

9. The improved coal supercritical water gasification power generation dual circulation system according to claim 8, Features: The bypass (10) is connected to the water-coal reactor (11) after heat exchange through the burner (12).

10. The improved coal supercritical water gasification power generation dual circulation system according to claim 8, Features: The bypass (10) is provided with a high-pressure pump (101).

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