CCPP quality-improving power generation system based on coal gas cooling and dehumidification

Abstract

The invention discloses a CCPP quality-improving power generation system based on coal gas cooling and dehumidification. Comprising a gas compressor, a gas inlet cooler and a combustion chamber which are sequentially communicated, wherein gas output by the gas compressor is cooled by the gas inlet cooler and then is led to the combustion chamber; the system further comprises a water chilling unit. A chilled water outlet of the water chilling unit is communicated with a chilled water inlet of the gas inlet cooler, and a chilled water outlet of the gas inlet cooler is communicated with a chilled water inlet of the water chilling unit, so that closed circulation of chilled water is formed. According to the method, the chilled water is used for indirectly cooling the gas at the inlet of the gas compressor, and meanwhile, the temperature and humidity of the gas before entering the gas compressor are reduced, so that the maximum power generation capacity of the CCPP unit in high-temperature weather is improved, and blade water attack and corrosion risks of the gas compressor are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation by-product coal gas of steel enterprises, and in particular to a CCPP quality improvement power generation system based on coal gas cooling and dehumidification. 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.

[0004] In addition, because gas dust collectors generally use wet electrostatic precipitators, the gas at the outlet of the dust collector is wet saturated gas, which puts great pressure on the safe operation of the gas compressor, especially the first-stage blades, and increases the risk of water hammer and water erosion on the blades. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the object of the present invention is to provide a CCPP quality improvement power generation system based on coal gas cooling and dehumidification.

[0006] To achieve the above-mentioned object, the CCPP quality improvement power generation system based on coal gas cooling and dehumidification of the present invention comprises a coal gas intake cooler, a coal gas compressor and a combustion chamber which are connected in sequence, wherein: the coal gas output by the coal gas compressor is cooled by the coal gas intake cooler and then passes to the combustion chamber;

[0007] It also includes a chiller; the chilled water outlet of the chiller is connected to the chilled water inlet of the gas intake cooler, and the chilled water outlet of the gas intake cooler is connected to the chilled water inlet of the chiller, forming a closed circulation of chilled water.

[0008] Furthermore, a gas dust collector is provided upstream of the gas compressor to remove dust from the gas entering the gas compressor.

[0009] Furthermore, it also includes a gas reflux cooler, the inlet of the gas reflux cooler is connected to the gas outlet of the gas compressor; the gas outlet of the gas reflux cooler is connected to the gas inlet of the gas dust collector.

[0010] 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:

[0011] The air outlet of the air compressor is connected to the combustion chamber, and the combustion chamber is connected to the gas turbine, the waste heat boiler, and the flue gas side of the chimney in sequence;

[0012] The waste heat boiler is connected with the steam turbine, condenser, condensate pump and low-temperature economizer in sequence on the steam-water side;

[0013] 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;

[0014] The steam generated by the waste heat boiler enters the steam turbine to perform work, and after condensing into condensate in the condenser, it enters the low-temperature economizer installed in the waste heat boiler through the condensate pump.

[0015] Furthermore, an air intake cooler is provided at the air inlet of the air compressor; the chilled water outlet of the chiller is also connected to the chilled water inlet of the air intake cooler, and the chilled water outlet of the air intake cooler is connected to the chilled water inlet of the chiller.

[0016] Furthermore, the gas intake cooler is arranged on the gas riser leading from the gas compressor outlet to the combustion chamber.

[0017] Furthermore, a drain device is provided on the horizontal gas pipeline from the gas intake cooler to the combustion chamber.

[0018] Furthermore, a water accumulation detection device is provided on the hydrophobic device.

[0019] Furthermore, a demister is provided on the coal gas intake cooler.

[0020] Furthermore, a tail waste heat recovery device is provided in the waste heat boiler;

[0021] The tail waste heat recovery device is located in the downstream flue of the low-temperature economizer;

[0022] Chillers The chillers use hot water type lithium bromide absorption chillers;

[0023] The tail waste heat recovery device adopts a flue gas-hot water heat exchanger, whose 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.

[0024] Beneficial Effects

[0025] 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.

[0026] 2) Since coal gas dust collectors generally use wet electrostatic dust removal, the coal gas at the dust collector outlet is wet saturated coal gas, which puts great pressure on 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. The present invention can reduce the humidity of the coal gas before entering the coal gas compressor through cooling and dehumidification, thereby reducing the risk of water hammer and corrosion of the blades of the coal gas compressor.

[0027] 3) 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 the maximum power generation benefits 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 load 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.

[0028] 4) The present invention can realize the intake cooling of coal gas and air, improve the output and coal gas consumption capacity of CCPP units in high temperature weather, and provide an effective means for the summer efficiency-enhancing operation and scheduling of the steel plant's self-provided power plant.

[0029] 5) 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structural connection relationship of the present invention.

[0031] In the figure: 1. Gas dust collector; 2. Gas intake cooler; 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. Air intake cooler; 18. Air filter; 19. Chilled water pump; 20. Hot water circulation pump. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The present invention aims to reduce the temperature of the coal gas at the inlet of the coal gas compressor by using the chilled water produced by the chiller, which can improve the output of the coal gas compressor and the output of the gas turbine in hot 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 coal gas temperature in summer. At the same time, through cooling and dehumidification, the humidity of the coal gas before entering the coal gas compressor can be reduced, thereby reducing the risk of water hammer and corrosion of the blades of the coal gas compressor.

[0037] Figure 1This is an embodiment of the CCPP power generation system based on coal gas cooling and dehumidification of the present invention, comprising a coal gas dust collector 1, a coal gas intake cooler 2, a coal gas compressor 3, a coal gas reflux cooler 4, and a combustion chamber 5, wherein:

[0038] The gas outlet of the gas dust collector 1 is connected to the gas inlet cooler 2 and the gas compressor 3 in sequence along the gas flow. The gas outlet of the gas compressor 3 is divided into two paths and 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.

[0039] The gas dust collector 1 adopts the principle of wet electrostatic dust removal, using a high-voltage electric field to ionize the gas. The dust in the gas is first separated from the airflow under the action of the electric field, adsorbed on the dust collecting plate, and then flushed into the wastewater collection pool at the bottom by the flushing water sprayed on the dust collecting plate, completing the dust removal process;

[0040] The gas inlet cooler 2 cools the gas entering the gas compressor 3 on the one hand, lowers the gas temperature, thereby increasing the gas volume acceptable to the gas compressor 3 and the combustion chamber 5, thereby increasing the unit output; on the other hand, it dehumidifies the gas entering the gas compressor 3, lowers the gas humidity, thereby improving the operating safety and stability of the gas compressor 3;

[0041] 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;

[0042] The coal gas inlet cooler 2 is provided with a demister to capture the mist particles and water droplets carried in the coal gas;

[0043] On the horizontal gas pipeline from the gas intake cooler 2 to the combustion chamber, a drain device is arranged at the valve, flow meter, rectifier plate, and the upward elbow of the riser, and a water accumulation detection device is arranged at the drain. The water accumulation detection device can be selected as needed. The present invention adopts a thermocouple to detect temperature changes 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; in order to ensure the accuracy of the detection, the thermocouple used for detection adopts a three-out-of-two redundancy mechanism to prevent false alarms.

[0044] As an improvement of the above embodiment, it also includes 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:

[0045] The air outlet of the air compressor 6 is connected to 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;

[0046] 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;

[0047] The outlet air of the air compressor 6 and the outlet gas of the gas compressor 3 are burned in the combustion chamber, 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;

[0048] 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.

[0049] As an improvement of the above embodiment, it also includes a tail waste heat recovery device 15, a chiller 16, an air intake cooler 17, an air filter 18, a hot water circulation pump 19, and a chilled water pump 20, wherein:

[0050] The tail waste heat recovery device 15 is arranged in the waste heat boiler, and is located in the downstream flue of the low-temperature economizer 14;

[0051] The chiller 16 is a hot water type lithium bromide absorption chiller;

[0052] The tail waste heat recovery device 15 adopts a flue gas-hot water heat exchanger, whose 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 19 is arranged on the connecting pipeline;

[0053] The chilled water outlet of the chiller 16 is connected to the chilled water inlet of the gas intake cooler 2, and the chilled water outlet of the gas intake cooler 2 is connected to the chilled water inlet of the chiller 16, forming a closed circulation of chilled water. A chilled water pump 20 is provided on the chilled water circulation pipeline;

[0054] The chilled water outlet of the chiller 16 is also in communication with the chilled water inlet of the air intake cooler 17, and the chilled water outlet of the air intake cooler 17 is in communication with the chilled water inlet of the chiller 16;

[0055] The air filter 18 is connected to the air intake cooler 17 and the air compressor 6 on the air side. The air intake cooler 17 can be arranged upstream of the air filter 18 on the air side, or downstream of the air filter 18 on the air side.

[0056] As an improvement of the above embodiment, a generator 11 is also included. In the present invention, the following forms 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.

[0057] 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.

[0058] 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.

[0059] 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 CCPP power generation system based on coal gas cooling and dehumidification, characterized by: It comprises a gas intake cooler, a gas compressor and a combustion chamber which are connected in sequence, wherein: the gas output by the gas compressor is cooled by the gas intake cooler and then flows to the combustion chamber; It also includes a chiller; the chilled water outlet of the chiller is connected to the chilled water inlet of the gas intake cooler, and the chilled water outlet of the gas intake cooler is connected to the chilled water inlet of the chiller, forming a closed circulation of chilled water.

2. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 1, characterized in that: A gas dust collector is arranged upstream of the gas compressor to remove dust from the gas entering the gas compressor.

3. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 2 is characterized in that: It also includes a gas reflux cooler, the inlet of the gas reflux cooler is connected to the gas outlet of the gas compressor; the gas outlet of the gas reflux cooler is connected to the gas inlet of the gas dust collector.

4. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 2 is characterized in that: It also includes air compressor, gas turbine, waste heat boiler, chimney, steam turbine, condenser, condensate pump, low temperature economizer, among which: The air outlet of the air compressor is connected to the combustion chamber, and the combustion chamber is connected to the gas turbine, the waste heat boiler, and the flue gas side of the chimney in sequence; 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 steam generated by the waste heat boiler enters the steam turbine to perform work, and after condensing into condensate in the condenser, it enters the low-temperature economizer installed in the waste heat boiler through the condensate pump.

5. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 4 is characterized in that: An air intake cooler is provided at the air intake of the air compressor; The chilled water outlet of the chiller is also communicated with the chilled water inlet of the air intake cooler, and the chilled water outlet of the air intake cooler is communicated with the chilled water inlet of the chiller.

6. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 1, characterized in that: The gas intake cooler is arranged on the gas riser from the gas compressor outlet to the combustion chamber.

7. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 1, characterized in that: A drain device is provided on the horizontal gas pipeline from the gas inlet cooler to the combustion chamber.

8. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 6, characterized in that: A water accumulation detection device is arranged on the hydrophobic device.

9. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 7, characterized in that: The coal gas intake cooler is provided with a demister.

10. The CCPP power generation system based on coal gas cooling and dehumidification according to claim 4, characterized in that: A tail waste heat recovery device is provided in the waste heat boiler; The tail waste heat recovery device is located in the downstream flue of the low-temperature economizer; Chillers The chillers use hot water type lithium bromide absorption chillers; The tail waste heat recovery device adopts a flue gas-hot water heat exchanger, whose 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.

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