Dry quenching supercritical carbon dioxide power generation thermodynamic system

Abstract

The invention relates to a dry quenching supercritical carbon dioxide power generation thermodynamic system which comprises a dry quenching boiler, a CO2-flue gas heat exchanger, a turbine, a power generator, a high-temperature heat regenerator, a low-temperature heat regenerator, a cooler, a main compressor and an auxiliary compressor. CO2 after acting is sequentially connected with a high-temperature heat regenerator and a low-temperature heat regenerator and then enters a cooler and an auxiliary compressor; cO2 entering the cooler is cooled, then enters the main compressor, then enters the low-temperature heat regenerator and then is converged with CO2 entering the auxiliary compressor, after entering the high-temperature heat regenerator, the CO2 enters the CO2-flue gas heat exchanger again for heat exchange, and dry quenching circulating gas subjected to CO2 heat exchange is subjected to steam-water heat exchange to generate steam for external supply. And the supercritical CO2 power generation technology can greatly improve the power generation efficiency and increase the power generation amount, and huge economic benefits can be brought to enterprises.

Description

Technical Field

[0001] The invention relates to the technical field of coking waste heat utilization, and in particular to a dry coke quenching supercritical carbon dioxide power generation thermal system. Background Art

[0002] The use of CDQ flue gas steam turbine units to generate electricity has the disadvantage of low power generation efficiency, which is difficult to overcome, because the steam Rankine cycle of the steam turbine unit is subject to the characteristics of the circulating working fluid. Most CDQ steam turbine generator units are condensing units. The low-temperature exhaust steam is condensed in the condenser, and most of the heat released is carried to the cooling tower by the circulating water and discharged into the atmosphere. This part of the condensation heat loss accounts for more than 40% of the total heat entering the steam turbine.

[0003] The power generation field has been exploring new technologies to increase power generation, and supercritical CO2 power generation technology is one of them. The applications of supercritical CO2 pressurization and heat exchange control in supercritical CO2 power generation have always been important projects for exploration and research in various fields. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a dry quenching supercritical carbon dioxide power generation thermal system. The present invention uses supercritical CO2 as the energy conversion working fluid, uses the heat of the high temperature section of the dry quenching cycle gas to heat the CO2, and utilizes the Brayton cycle principle to scientifically design and reasonably match the working fluid characteristics, thermal process, and system equipment to form a new type of power conversion technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A dry coke quenching supercritical carbon dioxide power generation thermal system comprises a dry coke quenching boiler, a CO2-flue gas heat exchanger, a turbine, a generator, a high-temperature regenerator, a low-temperature regenerator, a cooler, a main compressor and an auxiliary compressor. The CO2-flue gas heat exchanger is arranged on the top of the dry coke quenching boiler, the heat exchange outlet of the CO2-flue gas heat exchanger is connected to the turbine, the turbine is connected to the generator, the gas outlet of the turbine is connected to the high-temperature regenerator and the high-temperature side of the low-temperature regenerator in sequence, the high-temperature side outlet of the low-temperature regenerator is connected to the auxiliary compressor and the cooler respectively, the cooler outlet is connected to the main compressor, the main compressor outlet is connected to the low-temperature side of the low-temperature regenerator, the low-temperature side outlet of the low-temperature regenerator is connected to the low-temperature side of the low-temperature regenerator in parallel with the outlet of the auxiliary compressor, and the low-temperature side outlet of the high-temperature regenerator is connected to the inlet of the CO2-flue gas heat exchanger.

[0007] A supercritical carbon dioxide power generation thermal system for dry quenching coke comprises a dry quenching boiler, a CO2-flue gas heat exchanger, a turbine, a generator, a high-temperature regenerator, a low-temperature regenerator, a cooler, a main compressor and a sub-compressor. The CO2-flue gas heat exchanger is arranged at the front end of the dry quenching boiler, the dry quenching circulating gas outlet of the CO2-flue gas heat exchanger is connected to the circulating gas inlet of the dry quenching boiler, the heat exchange outlet of the CO2-flue gas heat exchanger is connected to the turbine, the turbine is connected to the generator, the gas outlet of the turbine is connected to the high-temperature regenerator and the high-temperature side of the low-temperature regenerator in sequence, the high-temperature side outlet of the low-temperature regenerator is respectively connected to the sub-compressor and the cooler, the cooler outlet is connected to the main compressor, the main compressor outlet is connected to the low-temperature side of the low-temperature regenerator, the low-temperature side outlet of the low-temperature regenerator is connected to the low-temperature side of the high-temperature regenerator in parallel with the outlet of the sub-compressor, and the low-temperature side outlet of the high-temperature regenerator is connected to the inlet of the CO2-flue gas heat exchanger.

[0008] Furthermore, the CO2-flue gas heat exchanger is fixed on the top of the dry coke quenching boiler using a suspension or support structure.

[0009] Furthermore, the CO2-flue gas heat exchanger is independently arranged at the front end of the dry coke quenching boiler.

[0010] Furthermore, the lower part of the dry coke quenching boiler is connected to a boiler steam-water system.

[0011] Furthermore, the boiler steam-water system includes boiler feed water and external steam supply.

[0012] Furthermore, the external supply of steam includes production operations, heating and power generation.

[0013] Furthermore, the boiler steam-water system is set according to the heat exchange range of the CO2-flue gas heat exchanger.

[0014] Furthermore, the heat exchange method of the CDQ supercritical carbon dioxide power generation thermal system is as follows:

[0015] S1. The high-temperature CDQ circulating gas first exchanges heat with the CO2 gas in the CO2-flue gas heat exchanger. The heated CO2 enters the turbine through the outlet of the CO2-flue gas heat exchanger to perform work and then supplies the generator to generate electricity.

[0016] S2, the CO2 after work is connected to the high temperature side of the high temperature regenerator and the high temperature side of the low temperature regenerator in sequence through the gas outlet of the turbine. After passing through the high temperature side of the low temperature regenerator, the CO2 is divided into two paths, one entering the cooler and the other entering the auxiliary compressor; the CO2 entering the cooler is cooled and then enters the main compressor and then enters the low temperature side of the low temperature regenerator; the CO2 entering the auxiliary compressor is compressed and merged with the CO2 at the low temperature side outlet of the low temperature regenerator, and enters the low temperature side of the high temperature regenerator to complete the heat exchange cooling of the CO2, and then the heat exchange cooled CO2 enters the CO2-flue gas heat exchanger again to absorb the heat of the CDQ cycle gas;

[0017] S3. After passing through the CO2-flue gas heat exchanger, the CDQ circulating gas is further heat-exchanged with the boiler steam-water system at the bottom of the CDQ boiler in the CDQ boiler. A large amount of steam is generated by heating the liquid water with the boiler feed water. The steam is sent out through the steam supply pipeline for production operations, power generation and heating. The CDQ circulating gas cooled by heat exchange is discharged through the bottom exhaust port of the CDQ boiler.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) The present invention uses supercritical CO2 as the energy conversion working fluid, uses the heat of the high temperature section of the CDQ circulating gas to heat CO2, and uses the Brayton cycle principle to scientifically design and reasonably match the working fluid characteristics, thermal process, and system equipment to form a new type of power conversion technology. Compared with the traditional steam power generation technology using water as the circulating medium, in the whole cycle, the working fluid CO2 has no phase change process, which reduces the consumption of circulating water, saves energy consumption, fully utilizes the CDQ circulating gas, and avoids the energy waste of the CDQ circulating gas.

[0020] 2) The CO2-flue gas heat exchanger is integrated in the upper part of the CDQ boiler and can be fixed by a suspension or supporting structure. The CO2-flue gas heat exchanger can also be arranged independently in front of the CDQ boiler. The heat in the CDQ circulating gas directly exchanges heat energy with CO2, which improves the utilization rate of the CDQ circulating flue gas, is beneficial to the heat absorption of the supercritical CO2 working medium, and helps to improve the power generation efficiency.

[0021] 3) The CDQ circulating gas first exchanges heat with CO2 and then exchanges heat with the liquid water in the boiler feed water in the boiler steam-water system, and the liquid water is heated into water vapor for external supply, thereby further improving the utilization rate of the CDQ circulating gas. The heat absorption temperature range of the CO2-flue gas heat exchanger is relatively large. The design of the CDQ boiler steam-water system is adjusted according to the heat absorption temperature range of the CO2-flue gas heat exchanger, thereby further fully utilizing the heat in the CDQ circulating flue gas, increasing the thermal energy conversion rate, and avoiding the waste of CDQ circulating gas energy.

[0022] 4) After passing through the CO2-flue gas heat exchanger, the quenching circulating gas is further heat-exchanged with the steam-water system of the dry coke quenching boiler to generate steam for external supply. The dry coke quenching boiler can produce steam with various parameters such as low pressure or medium pressure according to user needs. The steam is used for production operations, heating or power generation, etc. It has a wide range of uses, strong practicality, high utilization rate and high economic value.

[0023] 5) The system of supercritical CO2 waste heat power generation is relatively simple, with a more compact layout, which saves space. Supercritical CO2 power generation technology can greatly improve power generation efficiency, increase power generation, and bring huge economic benefits to enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention discloses a process flow chart of a supercritical carbon dioxide power generation thermal system for dry quenching of coke.

[0025] In the figure: 1. CDQ boiler; 2. CO2-flue gas heat exchanger; 3. Turbine; 4. Generator; 5. High-temperature regenerator; 6. Low-temperature regenerator; 7. Cooler; 8. Main compressor; 9. Auxiliary compressor. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0027] [Example 1] Figure 1As shown, a dry quenching supercritical carbon dioxide power generation thermal system includes a dry quenching boiler 1, a CO2-flue gas heat exchanger 2, a turbine 3, a generator 4, a high-temperature regenerator 5, a low-temperature regenerator 6, a cooler 7, a main compressor 8, and an auxiliary compressor 9. The CO2-flue gas heat exchanger 2 is integrated on the top of the dry quenching boiler 1 and is fixed by a suspension or supporting structure, so that the dry quenching system layout is more compact and reasonable. The CO2-flue gas heat exchanger 2 can also be arranged independently in front of the dry coke quenching boiler 1. The dry coke quenching circulating flue gas first passes through the CO2-flue gas heat exchanger 2 before exchanging heat with the steam-water heat exchange system in the dry coke quenching boiler 1. The dry coke quenching circulating flue gas has a higher thermal energy utilization rate and more sufficient thermal energy utilization. The heat exchange outlet of the CO2-flue gas heat exchanger 2 is connected to the turbine 3. Supercritical CO2 has excellent fluidity and thermal conductivity, and can convert more heat from the heat source into mechanical energy. The turbine 3 uses this part of the converted mechanical energy to generate electricity for the generator 4. The gas outlet of the turbine 3 is connected to the high-temperature regenerator in turn. 5 and the high temperature side of the low temperature regenerator 6, the high temperature side outlet of the low temperature regenerator 6 is connected to the auxiliary compressor 9 and the cooler 7 respectively, the outlet of the cooler 7 is connected to the main compressor 8, the outlet of the main compressor 8 is connected to the low temperature side of the low temperature regenerator 6, the low temperature side outlet of the low temperature regenerator 6 is connected in parallel with the outlet of the auxiliary compressor 9 and connected to the low temperature side of the high temperature regenerator 5, the low temperature side outlet of the high temperature regenerator 5 is connected to the inlet of the CO2-flue gas heat exchanger 2, the CO2 after doing work will enter the CO2-flue gas heat exchanger 2 again through the cooling and compression cycle to exchange heat with the dry quenching cycle flue gas, and the cycle is repeated to continuously provide power generation energy for the generator.

[0028] Furthermore, the lower part of the CDQ boiler 1 is connected to a boiler steam-water system.

[0029] Furthermore, the boiler steam-water system includes boiler feed water and external steam supply.

[0030] Furthermore, the external supply of steam includes production operations, heating and power generation.

[0031] Furthermore, the boiler steam-water system is set according to the heat exchange interval of the CO2-flue gas heat exchanger 2.

[0032] Furthermore, the heat exchange method of the CDQ supercritical carbon dioxide power generation thermal system is as follows:

[0033] S1, high-temperature CDQ circulating gas enters CDQ boiler 1, CO2-flue gas heat exchanger 2 is arranged on the top of CDQ boiler, high-temperature CDQ circulating gas first exchanges heat with CO2 gas in CO2-flue gas heat exchanger 2, heated CO2 enters turbine 3 through the outlet of CO2-flue gas heat exchanger 2 to perform work and then supplies generator 4 to generate electricity;

[0034] S2, the CO2 after work is connected to the high temperature side of the high temperature regenerator 5 and the high temperature side of the low temperature regenerator 6 in sequence through the gas outlet of the turbine 3. After passing through the high temperature side of the low temperature regenerator 6, the CO2 is divided into two paths, one path enters the cooler 7, and the other path enters the auxiliary compressor 9; the CO2 entering the cooler 7 is cooled and then enters the main compressor 8 and then enters the low temperature side of the low temperature regenerator 6; the CO2 entering the auxiliary compressor 8 is compressed and merged with the CO2 compressed at the low temperature side outlet of the low temperature regenerator 6, and enters the low temperature side of the high temperature regenerator 5 to complete the cooling and pressurization of the CO2, and then the cooled and pressurized CO2 enters the CO2-flue gas heat exchanger 2 again to absorb the heat of the dry coke quenching cycle gas;

[0035] S3. After passing through the CO2-flue gas heat exchanger 2, the CDQ circulating gas further exchanges heat with the boiler steam-water system at the bottom of the CDQ boiler 1. A large amount of steam is generated by heating the liquid water through the boiler feed water. The steam is sent out through the steam supply pipeline for production operations, power generation and heating. The CDQ circulating gas cooled by heat exchange is discharged through the bottom exhaust port of the bottom CDQ boiler 1.

[0036] [Example 2] A supercritical carbon dioxide power generation thermal system for dry quenching coke comprises a dry quenching boiler 1, a CO2-flue gas heat exchanger 2, a turbine 3, a generator 4, a high-temperature regenerator 5, a low-temperature regenerator 6, a cooler 7, a main compressor 8, and an auxiliary compressor 9. The CO2-flue gas heat exchanger 2 is independently arranged in front of the dry quenching boiler 1. The dry quenching circulating flue gas first passes through the CO2-flue gas heat exchanger 2 before heat exchange with the steam-water heat exchange system in the dry quenching boiler 1. The dry quenching circulating flue gas has a higher thermal energy utilization rate and more sufficient thermal energy utilization. The heat exchange outlet of the CO2-flue gas heat exchanger 2 is connected to the turbine 3. Supercritical CO2 has excellent fluidity and thermal conductivity, and can convert more heat from the heat source into mechanical energy. The turbine 3 converts this part of mechanical energy to generate electricity for the generator 4. The gas outlet of the turbine 3 is connected to the high-temperature sides of the high-temperature regenerator 5 and the low-temperature regenerator 6 in sequence. The high-temperature side outlet of the low-temperature regenerator 6 is connected to the auxiliary compressor 9 and the cooler 7 respectively. The outlet of the cooler 7 is connected to the main compressor 8. The outlet of the main compressor 8 is connected to the low-temperature side of the low-temperature regenerator 6. The low-temperature side outlet of the low-temperature regenerator 6 is connected in parallel with the outlet of the auxiliary compressor 9 and connected to the low-temperature side of the high-temperature regenerator 5. The low-temperature side outlet of the high-temperature regenerator 5 is connected to the inlet of the CO2-flue gas heat exchanger 2. The CO2 after doing work will enter the CO2-flue gas heat exchanger 2 again through the cooling and compression cycle to exchange heat with the dry quenching cycle flue gas. The cycle is repeated to continuously provide power generation energy for the generator.

[0037] Furthermore, the lower part of the CDQ boiler 1 is connected to a boiler steam-water system.

[0038] Furthermore, the boiler steam-water system includes boiler feed water and external steam supply.

[0039] Furthermore, the external supply of steam includes production operations, heating and power generation.

[0040] Furthermore, the boiler steam-water system is set according to the heat exchange interval of the CO2-flue gas heat exchanger 2.

[0041] Furthermore, the heat exchange method of the CDQ supercritical carbon dioxide power generation thermal system is as follows:

[0042] S1, high-temperature CDQ circulating gas enters CDQ boiler 1, CO2-flue gas heat exchanger 2 is independently arranged at the front end of CDQ boiler, high-temperature CDQ circulating gas first exchanges heat with CO2 gas in CO2-flue gas heat exchanger 2, heated CO2 enters turbine 3 through the outlet of CO2-flue gas heat exchanger 2 to perform work and then supplies generator 4 to generate electricity;

[0043] S2, the CO2 after work is connected to the high temperature side of the high temperature regenerator 5 and the high temperature side of the low temperature regenerator 6 in sequence through the gas outlet of the turbine 3. After passing through the high temperature side of the low temperature regenerator 6, the CO2 is divided into two paths, one path enters the cooler 7, and the other path enters the auxiliary compressor 9; the CO2 entering the cooler 7 is cooled and then enters the main compressor 8 and then enters the low temperature side of the low temperature regenerator 6; the CO2 entering the auxiliary compressor 8 is compressed and merged with the CO2 compressed at the low temperature side outlet of the low temperature regenerator 6, and enters the low temperature side of the high temperature regenerator 5 to complete the cooling and pressurization of the CO2, and then the cooled and pressurized CO2 enters the CO2-flue gas heat exchanger 2 again to absorb the heat of the dry coke quenching cycle gas;

[0044] S3. After passing through the CO2-flue gas heat exchanger 2, the CDQ circulating gas further exchanges heat with the boiler steam-water system at the bottom of the CDQ boiler 1. A large amount of steam is generated by heating the liquid water through the boiler feed water. The steam is sent out through the steam supply pipeline for production operations, power generation and heating. The CDQ circulating gas cooled by heat exchange is discharged through the bottom exhaust port of the bottom CDQ boiler 1.

[0045] The above description is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A supercritical carbon dioxide power generation thermal system for dry quenching of coke, comprising a dry quenching boiler, a CO2-flue gas heat exchanger, a turbine, a generator, a high-temperature regenerator, a low-temperature regenerator, a cooler, a main compressor, and an auxiliary compressor, characterized in that: The CO2-flue gas heat exchanger is arranged on the top of the dry quenching boiler. The heat exchange outlet of the CO2-flue gas heat exchanger is connected to the turbine, the turbine is connected to the generator, the gas outlet of the turbine is connected to the high-temperature regenerator and the high-temperature side of the low-temperature regenerator in sequence, the high-temperature side outlet of the low-temperature regenerator is connected to the auxiliary compressor and the cooler respectively, the cooler outlet is connected to the main compressor, the main compressor outlet is connected to the low-temperature side of the low-temperature regenerator, the low-temperature side outlet of the low-temperature regenerator is connected in parallel with the outlet of the auxiliary compressor and connected to the low-temperature side of the high-temperature regenerator, and the low-temperature side outlet of the high-temperature regenerator is connected to the inlet of the CO2-flue gas heat exchanger.

2. A supercritical carbon dioxide power generation thermal system for dry quenching of coke, comprising a dry quenching boiler, a CO2-flue gas heat exchanger, a turbine, a generator, a high-temperature regenerator, a low-temperature regenerator, a cooler, a main compressor, and an auxiliary compressor, characterized in that: The CO2-flue gas heat exchanger is arranged at the front end of the dry quenching boiler, the dry quenching circulating gas outlet of the CO2-flue gas heat exchanger is connected to the circulating gas inlet of the dry quenching boiler, the heat exchange outlet of the CO2-flue gas heat exchanger is connected to the turbine, the turbine is connected to the generator, the gas outlet of the turbine is connected to the high-temperature regenerator and the high-temperature side of the low-temperature regenerator in sequence, the high-temperature side outlet of the low-temperature regenerator is connected to the auxiliary compressor and the cooler respectively, the cooler outlet is connected to the main compressor, the main compressor outlet is connected to the low-temperature side of the low-temperature regenerator, the low-temperature side outlet of the low-temperature regenerator is connected in parallel with the outlet of the auxiliary compressor and connected to the low-temperature side of the high-temperature regenerator, and the low-temperature side outlet of the high-temperature regenerator is connected to the inlet of the CO2-flue gas heat exchanger.

3. The dry quenching supercritical carbon dioxide power generation thermal system according to claim 1, characterized in that: The CO2-flue gas heat exchanger is arranged on the top of the dry coke quenching boiler by using a suspension or supporting structure for fixing.

4. The dry quenching supercritical carbon dioxide power generation thermal system according to claim 2, characterized in that: The CO2-flue gas heat exchanger is independently arranged at the front end of the dry coke quenching boiler.

5. A dry quenching supercritical carbon dioxide power generation thermal system according to claim 1 or 2, characterized in that: The lower part of the dry coke quenching boiler is connected to the boiler steam-water system.

6. The dry quenching supercritical carbon dioxide power generation thermal system according to claim 5, characterized in that: The boiler steam-water system includes boiler feed water and steam external supply.

7. The dry quenching supercritical carbon dioxide power generation thermal system according to claim 6, characterized in that: The steam external supply includes production operation, heating and power generation.

8. The dry quenching supercritical carbon dioxide power generation thermal system according to claim 5, characterized in that: The boiler steam-water system is arranged according to the heat exchange interval of the CO2-flue gas heat exchanger.

9. A heat exchange method for a CDQ supercritical carbon dioxide power generation thermal system according to claim 1 or 2, characterized in that: The heat exchange method of the CDQ supercritical carbon dioxide power generation thermal system is as follows: S1. The high-temperature CDQ circulating gas first exchanges heat with the CO2 gas in the CO2-flue gas heat exchanger. The heated CO2 enters the turbine through the outlet of the CO2-flue gas heat exchanger to perform work and then supplies the generator to generate electricity. S2, the CO2 after work is connected to the high temperature side of the high temperature regenerator and the high temperature side of the low temperature regenerator in sequence through the gas outlet of the turbine. After passing through the high temperature side of the low temperature regenerator, the CO2 is divided into two paths, one entering the cooler and the other entering the auxiliary compressor; the CO2 entering the cooler is cooled and then enters the main compressor and then enters the low temperature side of the low temperature regenerator; The CO2 entering the auxiliary compressor is compressed and merged with the CO2 at the low temperature side outlet of the low temperature regenerator, and enters the low temperature side to complete the heat exchange cooling of the CO2. The CO2 cooled by heat exchange then enters the CO2-flue gas heat exchanger again to absorb the heat of the CDQ cycle gas. S3. After passing through the CO2-flue gas heat exchanger, the CDQ circulating gas is further heat-exchanged with the boiler steam-water system at the bottom of the CDQ boiler in the CDQ boiler. A large amount of steam is generated by heating the liquid water with the boiler feed water. The steam is sent out through the steam supply pipeline for production operations, power generation and heating. The CDQ circulating gas cooled by heat exchange is discharged through the bottom exhaust port of the CDQ boiler.

Images