CCPP unit output improving system based on high-temperature coal gas spray cooling

Abstract

The invention discloses a CCPP unit output improving system based on high-temperature coal gas spray cooling. Comprising a gas compressor, a gas inlet cooler and a combustion chamber which are sequentially communicated, and high-temperature gas output by the gas compressor is cooled by the gas inlet cooler and then is led to the combustion chamber. The high-temperature gas at the outlet of the gas compressor is humidified and cooled in a direct contact manner, so that the gas is quickly cooled, the output of the CCPP unit in summer is improved, and the problem that the output of the unit is limited due to high environment temperature and high gas temperature in summer is solved.

Description

Technical Field

[0001] The invention relates to a CCPP unit output enhancement system based on high-temperature coal gas spray cooling. 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 CCPP unit output enhancement system based on high-temperature coal gas spray cooling.

[0005] To achieve the above-mentioned purpose, the CCPP unit output improvement system based on high-temperature coal gas spray cooling of the present invention comprises a coal gas compressor, a coal gas intake cooler and a combustion chamber connected in sequence, wherein:

[0006] The high-temperature gas output by the gas compressor is cooled by the gas intake cooler and then passes into the combustion chamber.

[0007] Furthermore, a gas dust collector is provided upstream of the gas compressor to remove dust from the gas entering the gas compressor.

[0008] 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.

[0009] Furthermore, the coal gas intake cooler is a spray type coal gas intake cooler.

[0010] Furthermore, the gas intake cooler is arranged on the gas riser leading from the gas compressor outlet to the combustion chamber.

[0011] Furthermore, a drain device is provided on the horizontal gas pipeline from the gas intake cooler to the combustion chamber, and the installation positions include before the valve, before the flow meter, before the rectifier plate, and at the upward elbow of the riser.

[0012] Furthermore, a water accumulation detection device is provided on the hydrophobic device.

[0013] Furthermore, the water accumulation detection device is a thermocouple, which detects temperature changes through the thermocouple to determine whether there is water accumulation in the pipeline.

[0014] Furthermore, a water supply pump is provided on the water inlet pipeline of the coal gas intake cooler to form atomized water droplets with particle size meeting the standards.

[0015] Furthermore, it also includes an air compressor, a gas turbine, a waste heat boiler, a chimney, and a generator, wherein:

[0016] The air outlet of the air compressor is connected to the combustion chamber, and the combustion chamber is connected to the waste heat boiler and the chimney in sequence on the flue gas side. The exhaust gas at the outlet of the waste heat boiler is discharged to the atmosphere through the chimney;

[0017] The generator is connected to the gas compressor, the air compressor and the gas turbine through a coupling or a gear box.

[0018] The system of the present invention has the following advantages:

[0019] 1) Through direct contact humidification and cooling of the high-temperature gas at the outlet of the gas compressor, the gas is quickly cooled, the summer output of the CCPP unit is improved, and the problem of limited unit output due to high ambient temperature and gas temperature in summer is solved.

[0020] 2) The present invention adopts a cooling method of directly spraying water mist, which has less impact on the resistance on the gas side compared with the indirect cooling method of heat exchange by the surface cooler, and because of direct mixed contact, the gas cooling speed is faster.

[0021] 3) For most steel mills that have built CCPPs, the gas-fired power generation units are configured in combination with 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. This patent can improve the gas absorption capacity of the CCPP units and provide an effective means for the summer efficiency-enhancing operation of the steel mill's self-provided power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a CCPP unit output enhancement system based on high-temperature coal gas spray cooling according to an embodiment of the present invention.

[0023] In the figure: 1. Gas dust collector; 2. Gas compressor; 3. Gas intake cooler; 4. Gas return cooler; 5. Combustion chamber; 6. Air compressor; 7. Gas turbine; 8. Waste heat boiler; 9. Chimney; 10. Generator; 11. Water supply pump. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The present invention aims to achieve rapid cooling of coal gas by directly contacting and humidifying the high-temperature coal gas at the outlet of the coal gas compressor, thereby improving the summer output of the CCPP unit and solving the problem of limited unit output due to high ambient temperature and high coal gas temperature in summer. Various feasible methods can be used to cool the high-temperature coal gas. One embodiment of the present invention adopts a cooling method of directly spraying water mist. Compared with the indirect cooling method of heat exchange of the surface cooler, it has less impact on the resistance of the coal gas side, and because it is direct mixed contact, the coal gas cooling speed is faster.

[0029] Figure 1 The figure shows a CCPP unit output improvement system based on high-temperature coal gas spray cooling disclosed in one embodiment of the present invention, comprising a coal gas dust collector 1, a coal gas compressor 2, a coal gas intake cooler 3, a coal gas reflux cooler 4, and a combustion chamber 5, wherein:

[0030] The gas outlet of the gas dust collector 1 is connected to the gas inlet of the gas compressor 2. The gas outlet of the gas compressor 2 is divided into two paths and connected to the gas inlet of the gas intake cooler 3 and the gas inlet of the gas reflux cooler 4 respectively. The gas outlet of the gas reflux cooler 4 is connected to the gas inlet of the gas dust collector 1.

[0031] The coal gas dust collector 1 adopts the principle of wet electrostatic dust removal, using a high voltage electric field to ionize the coal gas. The dust in the coal gas is first separated from the airflow under the action of the electric field, adsorbed on the dust collecting stage, and then flushed into the wastewater collection pool at the bottom by the flushing water sprayed to the dust collecting stage, completing the dust removal process;

[0032] The function of the gas inlet cooler 3 is to cool the gas entering the gas compressor and reduce the gas temperature, so as to increase the gas volume acceptable to the gas compressor and the gas turbine, thereby increasing the unit output;

[0033] 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 2 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;

[0034] The coal gas inlet cooler 3 is provided with an atomizing nozzle, which can produce water mist with extremely small particle size;

[0035] The gas inlet cooler 3 is arranged on the gas riser from the gas compressor outlet to the combustion chamber. Compared with being arranged on a horizontal pipe, the water mist is more fully in contact with the gas, and water droplets are less likely to be brought into the combustion chamber with the air flow.

[0036] On the horizontal gas pipeline from the gas intake cooler 3 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.

[0037] The coal gas inlet cooler 3 is provided with an atomizing nozzle, which can produce water mist with extremely small particle size;

[0038] A water supply pump 11 is installed on the water inlet pipeline of the coal gas intake cooler 3, which can output water supply with sufficiently high pressure to the nozzle to form atomized water droplets with particle size meeting the standard.

[0039] The inlet water of the coal gas inlet cooler 3 is demineralized water or softened water.

[0040] As an improvement of the above embodiment, the CCPP unit output enhancement system based on high-temperature coal gas spray cooling further includes an air compressor 6, a gas turbine 7, a waste heat boiler 8, and a chimney 9, wherein:

[0041] 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;

[0042] The outlet air of the air compressor 6 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 8 through the gas turbine 7, and is discharged through the chimney 9 after heat exchange in the waste heat boiler 8.

[0043] As an improvement of the above embodiment, the CCPP unit output enhancement system based on high-temperature coal gas spray cooling also includes a generator 10, which is connected to the coal gas compressor 2, the air compressor 6, and the gas turbine 7 through a coupling or a gear box, and the gas turbine drives the generator 10 to generate electricity.

[0044] 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.

[0045] 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 unit output enhancement system based on high-temperature coal gas spray cooling, characterized in that: It includes a gas compressor, a gas intake cooler and a combustion chamber which are connected in sequence, wherein: The high-temperature gas output by the gas compressor is cooled by the gas intake cooler and then passes into the combustion chamber.

2. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling 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 unit output enhancement system based on high-temperature coal gas spray cooling according to claim 2, 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 unit output enhancement system based on high-temperature coal gas spray cooling according to claim 1, characterized in that: The coal gas intake cooler is a spray type coal gas intake cooler, which directly sprays water mist into the high temperature coal gas.

5. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling 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.

6. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling according to claim 1, characterized in that: A drain device is installed on the horizontal gas pipeline from the gas inlet cooler to the combustion chamber. The installation positions include before the valve, before the flow meter, before the rectifier plate, and at the upward elbow of the riser.

7. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling according to claim 6, characterized in that: A water accumulation detection device is arranged on the hydrophobic device.

8. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling according to claim 7, characterized in that: The water accumulation detection device is a thermocouple, which detects temperature changes through the thermocouple to determine whether there is water accumulation in the pipeline.

9. The CCPP unit output enhancement system based on high-temperature coal gas spray cooling according to claim 7, characterized in that: A water supply pump is arranged on the water inlet pipeline of the coal gas intake cooler to form atomized water droplets with particle size meeting the standard.

10. The CCPP unit output enhancement system based on high temperature coal gas spray cooling according to claim 7, characterized in that: It also includes air compressors, gas turbines, waste heat boilers, chimneys, and generators, including: The air outlet of the air compressor is connected to the combustion chamber, and the combustion chamber is connected to the waste heat boiler and the chimney in sequence on the flue gas side. The exhaust gas at the outlet of the waste heat boiler is discharged to the atmosphere through the chimney; The generator is connected to the gas compressor, the air compressor and the gas turbine through a coupling or a gear box.

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