Steel gas CCPP generator set summer output promotion system

Abstract

The application discloses a summer output improving system of a steel gas CCPP generator set. The system comprises a coal gas dust remover, a coal gas compressor and a water chilling unit, wherein the coal gas dust remover is provided with a coal gas dust remover water inlet pipe, and a waste water collecting pool is arranged at the bottom of the coal gas dust remover; the coal gas dust remover water inlet pipe is communicated with a chilled water outlet of the water chilling unit, the water chilling unit provides low-temperature chilled water to the coal gas dust remover through the coal gas dust remover water inlet pipe, so as to reduce the temperature of the coal gas; and the coal gas outlet of the coal gas dust remover is communicated with the coal gas inlet of the coal gas compressor. The low-temperature chilled water can replace or partially replace normal water supply, the temperature of the coal gas before entering the coal gas compressor can be reduced, the saturated coal gas humidity is also reduced, and then the water hammer and corrosion risk of the blades of the coal gas compressor are reduced.

Description

Technical Field

[0001] This invention relates to the field of power generation technology using by-product coal gas from steel enterprises, specifically a summer output enhancement system for a steel coal gas-fired CCPP generator set. Background Technology

[0002] Steel mills generate a large amount of by-product gas during the smelting process, including blast furnace gas, converter gas, and coke oven gas. After deducting the gas consumed in each smelting process, a surplus of gas, especially blast furnace gas, is usually remaining. To efficiently utilize this surplus gas, steel plants typically construct gas-fired power generation units. Among these, CCPP (combined cycle gas-fired power generation) is more efficient than the conventional BTG (boiler-turbine power generation) route, helping steel plants increase their self-generation rate and reduce carbon emissions, offering better overall benefits. It has been adopted by many steel plants in China and has achieved good operational results.

[0003] For most steel plants that have built CCPP (Compressed Corning Gas) generators, the gas-fired power generation units are configured in combination with conventional BTG (Burning Gas Tolerancing) units. To ensure maximum power generation revenue with the same amount of gas, steel plants generally try to keep the more efficient CCPP units at high load or even full capacity during operation, while the BTG units act as peak-shaving units, absorbing part of the load to absorb excess fluctuating gas volume. This operating strategy achieves the expected results under normal circumstances. However, in the high temperatures of summer, the high ambient temperature causes the output and efficiency of the CCPP units to fall below their design values, especially the unit output, which drops significantly. In this case, the output of the conventional BTG units must be increased to absorb the gas volume corresponding to the decrease in CCPP unit output, which undoubtedly weakens the steel plant's revenue. Therefore, how to improve the output capacity of CCPP units in high-temperature weather and increase the proportion of CCPP units in summer power generation is a common concern for all steel plants. Summary of the Invention

[0004] To overcome the above-mentioned defects, the purpose of this invention is to provide a summer output enhancement system for steel gas CCPP generator sets.

[0005] To achieve the above objectives, the present invention provides a summer output enhancement system for steel gas-fired CCPP generator sets, comprising a gas dust collector, a gas compressor, and a chiller unit, wherein:

[0006] The gas dust collector is equipped with a gas dust collector water inlet pipe and a wastewater collection tank at the bottom of the gas dust collector.

[0007] The gas dust collector's inlet pipe is connected to the chilled water outlet of the chiller unit. The chiller unit provides low-temperature chilled water to the gas dust collector through the gas dust collector's inlet pipe to reduce the temperature of the gas.

[0008] The gas outlet of the gas dust collector is connected to the gas inlet of the gas compressor.

[0009] Furthermore, the gas dust collector is equipped with a demister.

[0010] Furthermore, a condensate drain is installed on the horizontal gas pipeline from the gas dust collector to the gas compressor.

[0011] Furthermore, a water accumulation detection device is provided on the hydrophobic device.

[0012] Furthermore, it also includes a gas recirculation cooler; wherein,

[0013] The gas compressor has two gas outlets that are connected to the gas inlet of the gas reflux cooler and the gas inlet of the combustion chamber, respectively. The gas outlet of the gas reflux cooler is connected to the gas inlet of the gas dust collector.

[0014] Furthermore, it also includes an air compressor, gas turbine, waste heat boiler, chimney, steam turbine, condenser, condensate pump, and cryogenic economizer, among which:

[0015] The air outlet of the air compressor is connected to the air inlet of the combustion chamber, and the combustion chamber is sequentially connected to the gas turbine, waste heat boiler, and chimney on the flue gas side.

[0016] The waste heat boiler is connected in sequence to the steam turbine, condenser, condensate pump, and low-temperature economizer on the steam-water side;

[0017] The air from the air compressor and the gas from the gas compressor are burned in the combustion chamber. The resulting flue gas is fed into the waste heat boiler via a gas turbine. After heat exchange in the waste heat boiler, it is discharged through the chimney.

[0018] The waste heat boiler uses water as the heat exchange medium. The steam generated enters the steam turbine to do work, and is condensed into condensate in the condenser. The condensate is then pumped into the low-temperature economizer installed in the waste heat boiler.

[0019] Furthermore, it also includes a tail-end waste heat recovery unit and a hot water circulation pump;

[0020] The tail waste heat recovery unit is installed in the waste heat boiler, located in the downstream flue of the low-temperature economizer; the tail waste heat recovery unit adopts a flue gas-hot water heat exchanger, and its inlet and outlet are connected to the hot water outlet and hot water inlet of the chiller unit, respectively, and a hot water circulation pump is installed on the connecting pipeline.

[0021] Furthermore, it also includes a chilled water tank, an air spray chilled water pump, an air filter, and an air intake cooler, wherein:

[0022] The chilled water outlet of the chiller is connected to the water inlet of the chilled water tank, the water outlet of the chilled water tank is connected to the water inlet of the air spray refrigeration water pump, and the water outlet of the air spray refrigeration water pump is connected to the air intake cooler;

[0023] The air filter 22 is connected to the air intake cooler 23 and the air compressor 6 on the air side.

[0024] Furthermore, the inlet pipe of the gas dust collector is also connected to the normal water supply pipeline for gas dust removal. During non-high temperature seasons, the gas dust collector provides normal temperature cooling water through the normal water supply pipeline for gas dust removal. Valves are provided on both the normal water supply pipeline for gas dust removal and the chilled water pipeline for gas dust removal, enabling the switching between the normal water supply pipeline for gas dust removal and the chilled water pipeline for gas dust removal or the blending of partial flow rates.

[0025] Furthermore, a generator is also included;

[0026] The generator is connected to the gas compressor, the air compressor, and the gas turbine through a coupling or a gearbox for transmission. The gas turbine drives the generator to generate electricity; the steam turbine drives a separately provided generator to generate electricity; or,

[0027] The generator is connected to the gas compressor, the air compressor, the gas turbine, and the steam turbine through a coupling or a gearbox for transmission. The gas turbine and the steam turbine jointly drive the generator to generate electricity.

[0028] The present invention has the following advantages:

[0029] 1) The present invention can reduce the temperature of the gas at the inlet of the gas compressor, improve the output of the gas compressor and the output of the gas turbine in high temperature weather, thereby increasing the maximum power generation capacity of the CCPP unit, and solving the problem of limited unit output caused by high environmental temperature and gas temperature in summer.

[0030] 2) Since the gas dust collectors supporting steel plant CCPPPs generally adopt wet electrostatic precipitation, the gas at the outlet of the dust collector is wet saturated gas, which poses a great pressure on the safe operation of the gas compressor, especially the first-stage blades, and increases the risk of water hammer and erosion of the blades. Since the higher the gas temperature, the greater its saturated moisture content, the present invention can reduce the gas temperature before entering the gas compressor by using chilled water to replace or partially replace the normal water supply (supplied through a plate heat exchanger connected to a cooling tower, with a water temperature reaching 40°C in summer), and at the same time reduce the saturated gas humidity, thereby reducing the risk of water hammer and corrosion of the blades of the gas compressor.

[0031] 3) In the present invention, the driving heat source of the absorption chiller is entirely taken from the tail waste heat of the waste heat boiler, making full use of the end waste heat of the system. By only increasing a limited amount of pump power consumption, greater benefits of improving the quality and efficiency of the CCPP power generation system can be achieved.

[0032] 4) For most steel plants that have built CCPP (Compressed Power Plant) generators, the gas-fired power generation units are configured in combination with conventional BTG (Blockchain Toll Collection) units. To ensure maximum power generation revenue with the same amount of gas, the steel plant tries to keep the more efficient CCPP units at high load or even full capacity during operation, while the BTG units act as peak-shaving units, absorbing part of the load to absorb excess fluctuating gas volume. However, during the high temperatures of summer, the output of CCPP units drops significantly, and the corresponding gas can only be used to generate electricity in conventional BTG units, which undoubtedly causes economic losses. This invention can achieve intake cooling of gas and air, improving the output of CCPP units and the gas absorption capacity during high temperatures, providing an effective means for the summer efficiency-enhancing operation and scheduling of steel plant self-owned power plants. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structural connection relationship of the present invention.

[0034] In the diagram: 1. Gas dust collector; 2. Gas dust collector inlet pipe; 3. Gas compressor; 4. Gas reflux cooler; 5. Combustion chamber; 6. Air compressor; 7. Gas turbine; 8. Waste heat boiler; 9. Chimney; 10. Steam turbine; 11. Generator; 12. Condenser; 13. Condensate pump; 14. Low-temperature economizer; 15. Tail-end waste heat recovery unit; 16. Chiller unit; 17. Hot water circulation pump; 18. Gas dust collector chilled water pump; 19. Wastewater collection tank; 20. Chilled water tank; 21. Air spray chilled water pump; 22. Air filter; 23. Air intake cooler. Detailed Implementation

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] The present invention aims to reduce the temperature of the gas before it enters the gas compressor by replacing or partially replacing the normal water supply (supplied through a plate heat exchanger connected to a cooling tower, with a water temperature of up to 40°C in summer) with chilled water. This also reduces the humidity of the saturated gas, thereby reducing the risk of water hammer and corrosion on the gas compressor blades.

[0040] Figure 1 This embodiment of the summer output enhancement system for a steel gas-fired CCPP generator set of the present invention includes a gas dust collector 1, a gas dust collector inlet pipe 2, a gas compressor 3, a chiller unit 16, and a wastewater collection tank 19, wherein:

[0041] The gas dust collector 1 is equipped with a gas dust collector inlet pipe 2, and the bottom of the gas dust collector 1 is connected to the wastewater collection tank 19.

[0042] The gas dust collector inlet pipe 2 is connected to the chilled water outlet of the chiller unit 16, and the chiller unit 16 provides low-temperature chilled water to the gas dust collector through the gas dust collector inlet pipe 2.

[0043] The gas outlet of the gas dust collector 1 is connected to the gas inlet of the gas compressor 3;

[0044] The gas dust collector 1 adopts the principle of wet electrostatic precipitator. It uses a high-voltage electric field to ionize the gas. The dust in the gas becomes charged and is separated from the gas flow under the action of the electric field. It is then adsorbed onto the dust collection plate. Water from the gas dust collector inlet pipe 2 is sprayed onto the dust collection plate, washing the dust on the dust collection plate to the wastewater collection tank 19 at the bottom, thus completing the entire dust removal process.

[0045] As an improvement to the above embodiment, the gas dust collector 1 is also equipped with a demister, which can capture the mist particles and water droplets carried in the gas.

[0046] As an improvement to the above embodiment, a condensate drain device is installed on the horizontal gas pipeline from the gas dust collector 1 to the gas compressor 3 at the valve, flow meter, rectifier plate, and upward bend of the riser, and a water accumulation detection device is installed at the condensate drain. The water accumulation detection device can be selected as needed. In this invention, a thermocouple is used to detect temperature changes to determine whether there is water accumulation in the pipeline, so as to avoid water accumulation in the high-pressure gas pipeline, which may cause corrosion, thinning and other hidden dangers in the gas pipeline.

[0047] To ensure the accuracy of the detection, the thermocouples used for detection employ a redundancy mechanism of two out of three to prevent false alarms.

[0048] As an improvement to the above embodiment, it also includes a gas recirculation cooler 4, a combustion chamber 5, an air compressor 6, a gas turbine 7, a waste heat boiler 8, a chimney 9, a steam turbine 10, a condenser 12, a condensate pump 13, and a low-temperature economizer 14, wherein:

[0049] The gas outlet of the gas compressor 3 is divided into two paths, which are connected to the gas inlet of the gas reflux cooler 4 and the gas inlet of the combustion chamber 5 respectively. The gas outlet of the gas reflux cooler 4 is connected to the gas inlet of the gas dust collector 1.

[0050] The function of the gas reflux cooler 4 is to rapidly reflux and cool the high-temperature gas at the outlet of the gas compressor 3 when the gas turbine is reduced or shedding load, and then send it to the inlet of the gas dust collector 1 for recycling.

[0051] The air outlet of the air compressor 6 is connected to the air inlet of the combustion chamber 5. The combustion chamber 5 is sequentially connected to the gas turbine 7, the waste heat boiler 8, and the chimney 9 on the flue gas side.

[0052] Waste heat boiler 8 is connected in sequence to steam turbine 10, condenser 12, condensate pump 13, and low temperature economizer 14 on the steam and water side;

[0053] The outlet air of the air compressor 6 and the outlet gas of the gas compressor are burned in the combustion chamber 5. The resulting flue gas is fed into the waste heat boiler 8 through the gas turbine 7. After heat exchange in the waste heat boiler 8, it is discharged through the chimney 9.

[0054] Waste heat boiler 8 uses water as the heat exchange medium. The steam generated by it enters steam turbine 10 to do work, and is condensed into condensate in condenser 12. After condensation, it enters low-temperature economizer 14 installed in waste heat boiler 8 through condensate pump 13.

[0055] As an improvement to the above embodiment, it also includes a tail-end waste heat recovery unit 15 and a hot water circulation pump 17, wherein:

[0056] The tail waste heat recovery unit 15 is installed in the waste heat boiler 8, located in the downstream flue of the low-temperature economizer 14; the tail waste heat recovery unit 15 adopts a flue gas-hot water heat exchanger, and its inlet and outlet are connected to the hot water outlet and hot water inlet of the chiller unit 16, respectively, and a hot water circulation pump 17 is installed on the connecting pipeline.

[0057] As an improvement to the above embodiment, it also includes a chilled water tank 20, an air spray chilled water pump 21, an air filter 22, and an air intake cooler 23, wherein:

[0058] The chilled water outlet of the chiller unit 16 is connected to the inlet of the chilled water tank 20, the outlet of the chilled water tank is connected to the inlet of the gas dust removal chilled water pump 18 and / or the air spray chilled water pump 21, and the outlet of the air spray chilled water pump 21 is connected to the air intake cooler 23.

[0059] Gas dust collector chilled water pump 18 and air spray chilled water pump 21 supply water to gas dust collector 1 and air intake cooler 23, respectively. Since the gas dust collector 1 and air intake cooler 23 require different water supply pressures, separate pumps with the required head are installed. Air intake cooler can be installed as needed; it may be omitted if the site space is limited and layout is difficult.

[0060] The air filter 22 is connected to the air intake cooler 23 and the air compressor 6 on the air side. The air intake cooler 23 can be located upstream of the air filter 22 on the air side or downstream of the air filter 22 on the air side.

[0061] As an improvement to the above embodiment, valves are installed on both the gas dust collector inlet pipe and the gas dust collector chilled water pipe, which can realize the switching between the normal water supply mode of the dust collector under non-summer conditions and the chilled water supply mode under summer conditions, and can also realize the mixed regulation of normal water supply and chilled water supply.

[0062] As an improvement to the above embodiments, the generator 11 is also included. In this invention, it can be configured as follows: the generator 11 is connected to the gas compressor 3, the air compressor 6, and the gas turbine 7 via a coupling or gearbox, the gas turbine drives the generator 11 to generate electricity, and the steam turbine 10 drives a separately configured generator to generate electricity; or the generator 11 is connected to the gas compressor 3, the air compressor 6, the gas turbine 7, and the steam turbine 10 via a coupling or gearbox, and the gas turbine 7 and the steam turbine 10 jointly drive the generator 11 to generate electricity.

[0063] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described above. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications made without departing from the concept and scope of the present invention should be considered within the scope of protection of the present invention.

[0064] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A summer output boosting system for a steel gas-fired CCPP generator set, characterized in that, This includes a gas dust collector, a gas compressor, and a chiller unit, among which: The gas dust collector is equipped with a gas dust collector water inlet pipe and a wastewater collection tank at the bottom of the gas dust collector. The gas dust collector's inlet pipe is connected to the chilled water outlet of the chiller unit. The chiller unit provides low-temperature chilled water to the gas dust collector through the gas dust collector's inlet pipe to reduce the temperature of the gas. The gas outlet of the gas dust collector is connected to the gas inlet of the gas compressor; It also includes a gas recirculation cooler; among which, The gas compressor's gas outlet is split into two branches, connected to the gas inlet of the gas reflux cooler and the gas inlet of the combustion chamber, respectively. The gas outlet of the gas reflux cooler is connected to the gas inlet of the gas dust collector. It also includes air compressors, gas turbines, waste heat boilers, chimneys, steam turbines, condensers, condensate pumps, and cryogenic economizers, among which: The air outlet of the air compressor is connected to the air inlet of the combustion chamber, and the combustion chamber is sequentially connected to the gas turbine, waste heat boiler, and chimney on the flue gas side. The waste heat boiler is connected in sequence to the steam turbine, condenser, condensate pump, and low-temperature economizer on the steam-water side; The air from the air compressor and the gas from the gas compressor are burned in the combustion chamber. The resulting flue gas is fed into the waste heat boiler via a gas turbine. After heat exchange in the waste heat boiler, it is discharged through the chimney. The waste heat boiler uses water as the heat exchange medium. The steam generated enters the steam turbine to do work, and is condensed into condensate in the condenser. The condensate is then pumped into the low-temperature economizer installed in the waste heat boiler. It also includes a tail-end waste heat recovery unit and a hot water circulation pump; The tail waste heat recovery unit is installed in the waste heat boiler, located in the downstream flue of the low-temperature economizer; the tail waste heat recovery unit adopts a flue gas-hot water heat exchanger, and its inlet and outlet are connected to the hot water outlet and hot water inlet of the chiller unit, respectively, and a hot water circulation pump is installed on the connecting pipeline. It also includes a chilled water tank, an air spray chilled water pump, an air filter, and an air intake cooler, among which: The chilled water outlet of the chiller unit is connected to the inlet of the chilled water tank, the outlet of the chilled water tank is connected to the inlet of the air spray chilled water pump, and the outlet of the air spray chilled water pump is connected to the air intake cooler. The air filter is connected to the air intake cooler and air compressor on the air side.

2. The summer output boosting system for steel gas-fired CCPP generator sets as described in claim 1, characterized in that, The gas dust collector's inlet pipe is also connected to the normal gas dust collector water supply line. During non-high-temperature seasons, the gas dust collector is supplied with ambient temperature cooling water through the normal gas dust collector water supply line. Valves are installed on both the normal gas dust collector water supply line and the gas dust collector chilled water line, which can realize the switching of the normal gas dust collector water supply line and the gas dust collector chilled water line or the partial mixing of flow rates.

3. The summer output boosting system for steel gas-fired CCPP generator sets as described in claim 1, characterized in that, A condensate drain device is installed on the horizontal gas pipeline from the gas dust collector to the gas compressor.

4. The summer output boosting system for steel gas-fired CCPP generator sets as described in claim 3, characterized in that, The hydrophobic device is equipped with a water accumulation detection device.

5. The summer output boosting system for steel gas-fired CCPP generator sets as described in claim 1, characterized in that, The gas dust collector is equipped with a demister.

6. The summer output boosting system for steel gas-fired CCPP generator sets as described in claim 1, characterized in that, It also includes generators; The generator is connected to the gas compressor, air compressor, and gas turbine via a coupling or gearbox; the gas turbine drives the generator to generate electricity; the steam turbine drives a separately installed generator to generate electricity; or... The generator is connected to the gas compressor, air compressor, gas turbine, and steam turbine via a coupling or gearbox. The gas turbine and steam turbine work together to drive the generator to produce electricity.

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