Summer output improving system for steel gas CCPP generator set

Abstract

The invention discloses a summer output improving system for a steel gas CCPP generator set. Comprising a coal gas dust remover, a coal gas compressor and a water chilling unit, a coal gas dust remover water inlet pipe is arranged on the coal gas dust remover, and a waste water collecting pool is arranged at the bottom of the coal gas dust remover; the gas dust remover water inlet pipe is communicated with a chilled water outlet of the water chilling unit, and the water chilling unit provides low-temperature chilled water for the gas dust remover through the gas dust remover water inlet pipe so as to reduce the temperature of gas; a gas outlet of the gas dust remover is communicated with a gas inlet of the gas compressor. According to the invention, normal water supply is replaced or partially replaced by chilled water, so that the temperature of gas before entering the gas compressor can be reduced, the humidity of saturated gas is also reduced, and the blade water attack and corrosion risk of the gas compressor is further reduced.

Description

Technical Field

[0001] The invention relates to the technical field of power generation by-product gas of steel enterprises, and in particular to a summer output enhancement system for a steel gas CCPP generator set. Background Art

[0002] During the smelting process, steel enterprises will produce a large amount of by-product gas, including blast furnace gas, converter gas, coke oven gas, etc. In addition to the consumption of each smelting process, there is generally still some surplus gas, especially blast furnace gas. In order to make efficient use of the remaining gas, steel mills generally build gas generator sets. Among them, CCPP (combined cycle gas-steam power generation) is more efficient than the conventional BTG (boiler-turbine power generation) route, which is beneficial for steel mills to increase their self-generation rate and reduce carbon emissions. It has good comprehensive benefits and has been applied in many domestic steel mills and has achieved good operating results.

[0003] For most steel mills that have built CCPPs, gas-fired generators are configured in combination with CCPP units and conventional BTG units. In order to ensure that the maximum power generation revenue can be obtained with the same amount of gas, steel mills generally try to ensure that the more efficient CCPP units are at high load or even full load during operation, while the BTG units serve as peak-shaving units and bear part of the load to absorb the remaining fluctuating gas. This operation strategy can achieve the expected results under normal circumstances, but in hot summer weather, the high ambient temperature will cause the output and efficiency of the CCPP units to be lower than the design values, especially the unit output, which drops significantly. At this time, the output of the conventional BTG units can only be increased to absorb the gas corresponding to the decrease in the output of the CCPP units, which will undoubtedly weaken the benefits of the steel mills. Therefore, how to improve the output capacity of the CCPP units in hot weather and increase the proportion of power generation of the CCPP units in summer is a common concern of steel mills. Summary of the invention

[0004] In order to overcome the above-mentioned defects, the object of the present invention is to provide a summer output enhancement system for a steel coal gas CCPP generator set.

[0005] To achieve the above-mentioned purpose, the summer output improvement system of the steel gas CCPP generator set of the present invention comprises a gas dust collector, a gas compressor and a chiller, wherein:

[0006] The gas dust collector is provided with a gas dust collector water inlet pipe, and the bottom of the gas dust collector is provided with a wastewater collection tank;

[0007] The water inlet pipe of the gas dust collector is connected to the chilled water outlet of the chiller, and the chiller provides low-temperature chilled water to the gas dust collector through the water inlet pipe of the gas dust collector to reduce the temperature of the gas;

[0008] The gas outlet of the gas dust collector is communicated with the gas inlet of the gas compressor.

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

[0010] Furthermore, a drain device is provided 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 reflux cooler; wherein,

[0013] The gas outlet of the gas compressor is divided into two paths and is respectively connected with the gas inlet of the gas reflux cooler and the gas inlet of the combustion chamber. The gas outlet of the gas reflux cooler is connected with the gas inlet of the gas dust collector.

[0014] Furthermore, it also includes an air compressor, a gas turbine, a waste heat boiler, a chimney, a steam turbine, a condenser, a condensate pump and a low-temperature economizer, wherein:

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

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

[0017] The outlet air of the air compressor and the outlet gas of the gas compressor are burned in the combustion chamber, and the generated flue gas is introduced into the waste heat boiler through the gas turbine, and is discharged through the chimney after heat exchange in the waste heat boiler;

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

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

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

[0021] Further, 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 chilled water pump, and the water outlet of the air spray chilled water pump is connected to the air intake cooler;

[0023] The air filter 22 is in communication with the air intake cooler 23 and the air compressor 6 on the air side.

[0024] Furthermore, the water inlet pipe of the gas dust collector is also connected to the normal water supply pipeline of the gas dust collector. The gas dust collector provides normal temperature cooling water through the normal water supply pipeline of the gas dust collection in the non-high temperature season. Valves are provided on the normal water supply pipeline of the gas dust collection and the chilled water pipeline of the gas dust collection, which can realize the switching of the normal water supply pipeline of the gas dust collection and the chilled water pipeline of the gas dust collection or partial flow mixing.

[0025] Further, a generator is included;

[0026] The generator is connected to the gas compressor, air compressor and gas turbine through a coupling or a gear box, the gas turbine drives the generator to generate electricity; the steam turbine drives a separate generator to generate electricity; or,

[0027] The generator is connected to the gas compressor, air compressor, gas turbine and steam turbine through a coupling or a gear box, and the gas turbine and 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, and can increase the output of the gas compressor and the output of the gas turbine in high temperature weather, thereby improving the maximum power generation capacity of the CCPP unit and solving the problem of limited unit output due to high ambient temperature and gas temperature in summer.

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

[0031] 3) The driving heat source of the absorption chiller in the present invention is all taken from the tail waste heat of the waste heat boiler, which makes full use of the terminal waste heat of the system. Only by increasing the limited power consumption of the water pump, greater benefits can be obtained from improving the quality and efficiency of the CCPP power generation system.

[0032] 4) For most steel mills that build CCPP, the gas-fired power generation units adopt a combination of CCPP units and conventional BTG units. In order to ensure the maximum power generation revenue with the same amount of gas, the steel mills try to ensure that the more efficient CCPP units are at high load or even full load during operation, while the BTG units serve as peak-shaving units, taking on part of the load to absorb the remaining fluctuating gas. However, in hot summer weather, the output of the CCPP units drops significantly, and the corresponding gas can only be used to generate electricity in conventional BTG units, which will undoubtedly cause economic losses. The present invention can achieve intake cooling of gas and air, improve the output and gas absorption capacity of the CCPP units in high temperature weather, and provide an effective means for the summer efficiency-enhancing operation and scheduling of the steel mill's self-provided power plant. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0034] In the figure: 1. Gas dust collector; 2. Gas dust collector water 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 waste heat recovery device; 16. Chiller; 17. Hot water circulation pump; 18. Gas dust removal chilled water pump; 19. Waste water collection tank; 20. Chilled water tank; 21. Air spray chilled water pump; 22. Air filter; 23. Air intake cooler. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

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

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The present invention aims to replace or partially replace the normal water supply (supplied through a plate heat exchanger connected to a cooling tower, the water temperature can reach 40°C in summer) with chilled water, thereby reducing the temperature of the gas before entering the gas compressor, while also reducing the humidity of the saturated gas, thereby reducing the risk of water hammer and corrosion on the blades of the gas compressor.

[0040] Figure 1 This is an embodiment of the summer output improvement system of the steel gas CCPP generator set of the present invention, comprising a gas dust collector 1, a gas dust collector water inlet pipe 2, a gas compressor 3, a chiller 16, and a wastewater collection tank 19, wherein:

[0041] The gas dust collector 1 is provided with a gas dust collector water 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 water inlet pipe 2 is connected to the chilled water outlet of the chiller 16, and the chiller 16 provides low-temperature chilled water to the gas dust collector through the gas dust collector water 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, and uses a high-voltage electric field to ionize the gas. The charged dust in the gas is first separated from the airflow under the action of the electric field and adsorbed on the dust collecting plate. Water from the water inlet pipe 2 of the gas dust collector is sprayed onto the dust collecting plate, and the dust on the dust collecting plate is flushed to the wastewater collection tank 19 at the bottom, completing the entire dust removal process.

[0045] As an improvement of the above embodiment, the coal gas dust collector 1 is further provided with a demister to capture the mist particles and water droplets carried in the coal gas.

[0046] As an improvement of the above embodiment, on the horizontal gas pipeline from the gas dust collector 1 to the gas compressor 3, a drain device is provided at the valve, flow meter, rectifier plate, and the upward elbow of the riser, and a water accumulation detection device is provided at the drain; the water accumulation detection device can be selected as needed. The present invention adopts a thermocouple, and the temperature change is detected by the thermocouple to determine whether there is water accumulation in the pipeline, so as to avoid water accumulation in the high-pressure gas pipeline, causing hidden dangers such as corrosion and thinning of the gas pipeline;

[0047] In order to ensure the accuracy of detection, the thermocouples used for detection adopt a two-out-of-three redundancy mechanism to prevent false alarms.

[0048] As an improvement of the above embodiment, it also includes a gas reflux 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 and is respectively connected to the gas inlet of the gas reflux cooler 4 and the gas inlet of the combustion chamber 5. 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 coal gas reflux cooler 4 is to quickly reflux and cool the high-temperature coal gas at the outlet of the coal gas compressor 3 when the gas turbine is under load reduction or load rejection, and send it to the inlet of the coal 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, and the combustion chamber 5 is connected to the gas turbine 7, the waste heat boiler 8, and the chimney 9 in sequence on the flue gas side;

[0052] The waste heat boiler 8 is connected with the steam turbine 10, the condenser 12, the condensate pump 13, and the low-temperature economizer 14 in sequence on the steam-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, and the generated flue gas is passed through the gas turbine 7 to the waste heat boiler 8, and is discharged through the chimney 9 after heat exchange in the waste heat boiler 8;

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

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

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

[0057] As an improvement of 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 16 is connected to the water inlet of the chilled water tank 20, the water outlet of the chilled water tank is connected to the water inlet of the gas dust removal chilled water pump 18 and / or the air spray chilled water pump 21, and the water outlet of the air spray chilled water pump 21 is connected to the air intake cooler 23.

[0059] The gas dust removal chilled water pump 18 and the air spray chilled water pump 21 supply water to the gas dust collector 1 and the air intake cooler 23 respectively. Since the water supply pressures required by the gas dust collector 1 and the air intake cooler 23 are different, water pumps with required lifts are respectively provided. The air intake cooler can be provided as required, and may not be provided if the on-site space is tight and the 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 arranged upstream of the air filter 22 on the air side, and can also be arranged downstream of the air filter 22 on the air side.

[0061] As an improvement on the above embodiment, valves are provided on the gas dust collector water inlet pipe and the gas dust collector chilled water pipeline, 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 of the above embodiment, of course, a generator 11 is also included. In the present invention, the following form can be adopted: the generator 11 is connected to the gas compressor 3, the air compressor 6, and the gas turbine 7 through a coupling or a gear box, the gas turbine drives the generator 11 to generate electricity, and the steam turbine 10 drives a separately arranged 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 through a coupling or a gear box, and the gas turbine 7 and the steam turbine 10 jointly drive the generator 11 to generate electricity.

[0063] The present invention is described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. Many other changes and modifications that do not depart from the concept and scope of the present invention should be regarded as the protection scope of the present invention.

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

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A summer output improvement system for steel gas CCPP generator sets, characterized in that: Including gas dust collector, gas compressor and chiller, including: The gas dust collector is provided with a gas dust collector water inlet pipe, and the bottom of the gas dust collector is provided with a wastewater collection tank; The water inlet pipe of the gas dust collector is connected to the chilled water outlet of the chiller, and the chiller provides low-temperature chilled water to the gas dust collector through the water inlet pipe of the gas dust collector to reduce the temperature of the gas; The gas outlet of the gas dust collector is communicated with the gas inlet of the gas compressor.

2. The summer output enhancement system for the steel gas CCPP generator set according to claim 1, characterized in that: The gas dust collector water inlet pipe is also connected to the normal water supply pipeline of the gas dust collector. The gas dust collector provides normal temperature cooling water through the normal water supply pipeline of the gas dust collector in the non-high temperature season. Valves are provided on the normal water supply pipeline of the gas dust collection and the gas dust collection chilled water pipeline, which can realize the switching of the normal water supply pipeline of the gas dust collection and the gas dust collection chilled water pipeline or partial flow mixing.

3. The summer output enhancement system for the steel gas CCPP generator set according to claim 1, characterized in that: A drain device is installed on the horizontal gas pipeline from the gas dust collector to the gas compressor.

4. The summer output enhancement system for the steel gas CCPP generator set according to claim 1, characterized in that: A water accumulation detection device is arranged on the hydrophobic device.

5. The summer output enhancement system for the steel gas CCPP generator set according to claim 1, characterized in that: Also includes a gas reflux cooler; wherein, The gas outlet of the gas compressor is divided into two paths and is respectively connected with the gas inlet of the gas reflux cooler and the gas inlet of the combustion chamber. The gas outlet of the gas reflux cooler is connected with the gas inlet of the gas dust collector.

6. The summer output enhancement system for the steel gas CCPP generator set according to claim 5, characterized in that: It also includes air compressor, gas turbine, waste heat boiler, chimney, steam turbine, condenser, condensate pump and low-temperature economizer, including: The air outlet of the air compressor is connected to the air inlet of the combustion chamber, and the combustion chamber is connected to the gas turbine, the waste heat boiler, and the chimney in sequence on the flue gas side; The waste heat boiler is connected with the steam turbine, condenser, condensate pump and low-temperature economizer in sequence on the steam-water side; The outlet air of the air compressor and the outlet gas of the gas compressor are burned in the combustion chamber, and the generated flue gas is introduced into the waste heat boiler through the gas turbine, and is discharged through the chimney after heat exchange in the waste heat boiler; The waste heat boiler uses water as the heat exchange medium. The steam it generates enters the steam turbine to do work, and is condensed into condensate in the condenser and then enters the low-temperature economizer installed in the waste heat boiler through the condensate pump.

7. The summer output enhancement system for the steel coal gas CCPP generator set according to claim 6, characterized in that: It also includes a tail waste heat recovery device and a hot water circulation pump; The tail waste heat recovery device is arranged in the waste heat boiler, and is located in the downstream flue of the low-temperature economizer; the tail waste heat recovery device adopts a flue gas-hot water heat exchanger, and its water inlet and outlet are respectively connected to the hot water outlet and hot water inlet of the chiller, and a hot water circulation pump is arranged on the connecting pipeline.

8. The summer output enhancement system for the steel coal gas CCPP generator set according to claim 7, characterized in that: Also includes a chilled water tank, an air spray chilled water pump, an air filter and an air intake cooler, wherein: 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 chilled water pump, and the water outlet of the air spray chilled water pump is connected to the air intake cooler; The air filter 22 is in communication with the air intake cooler 23 and the air compressor 6 on the air side.

9. The summer output enhancement system for steel coal gas CCPP generator set according to claim 1, characterized in that: The coal gas dust collector is provided with a demister.

10. The summer output enhancement system for steel coal gas CCPP generator set according to claim 7, characterized in that: Also includes a generator; The generator is connected to the gas compressor, air compressor and gas turbine through a coupling or a gear box, the gas turbine drives the generator to generate electricity; the steam turbine drives a separate generator to generate electricity; or, The generator is connected to the gas compressor, air compressor, gas turbine and steam turbine through a coupling or a gear box, and the gas turbine and steam turbine jointly drive the generator to generate electricity.

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