The power plant boiler flue gas waste heat recovery utilizes system
Technical field
The utility model relates to a kind of power plant boiler flue gas waste heat recovery and utilizes system.
Background technology
The air preheater of thermal power plant is a kind of heat exchanger, the high-temperature flue gas cold wind preceding with entering boiler that ejects through boiler economizer carries out heat exchange, but air mass flow is less than flue gas flow, air side and fume side exchange heat are asymmetric in the air preheater, high-grade fume afterheat is not fully effectively utilized, and discharges from chimney; Advocating energetically under the background of energy-saving and emission-reduction now, for this coal-burning boiler of thermal power plant, how to reduce the flue gas heat-energy losses, thereby energy savings, the protection environment very important meaning is arranged.Flue gas heat-energy losses in the boiler operatiopn is a most important heat-energy losses, if can the flue gas heat of boiler maximized reclaim and the generating set that is used in, then can improve boiler operating efficiency and economic benefit.
As shown in Figure 1, boiler 10 air are imported behind blower fan 11, air preheater 12 usually, and 12 pairs of air heat of air preheater are to improve boiler efficiency, to cut down the consumption of energy; The discharge flue gas of boiler 10 is discharged to chimney 17 behind air preheater 12, deduster 13, air-introduced machine 14, booster fan 15, desulfurizing tower 16 successively, and obviously the heat energy in the boiler smoke is arranged by sky, causes heat-energy losses; Boiler 10 steam export 21 generatings of steam turbine 20 rear drive generators, the defeated boiler 10 of getting back to of the steam after steam turbine 20 will do work by heat regenerative system 22 to; Heat regenerative system 22 comprises the condensate water heater of condenser 23 and a plurality of series connection, condenser 23 is connected between the head end condensate water heater of steam turbine 20 and heat regenerative system 22, tail end condensate water heater connects boiler 10, each condensate water heater also connects the end that draws gas of steam turbine 20 respectively, heat regenerative system 22 front end condensate water heaters are low pressure condensate water heater 25, and tail end condensate water heater is a high pressure condensate water heater 24.
For fear of the flue gas heat-energy losses, in the past for the recovery of boiler smoke heat with utilize method mainly as follows:
The a plurality of heat exchangers of serial connection in the boiler smoke passage, the heat that utilizes heat exchange to obtain is used for heating the boiler feedwater of heat regenerative system, draws gas thereby reduce steam; multiple electricity, or heating enters the air of boiler, the raising boiler efficiency; or heat the flue gas that enters chimney, be beneficial to environmental protection.The heat transferring medium input/output terminal that is used for heating the heat exchanger of heat regenerative system boiler feedwater can be connected in series or be parallel to the condensate water heater of heat regenerative system, other heat exchangers can be connected in series thereafter successively, because flue-gas temperature reduces step by step in the boiler smoke passage, if and the boiler smoke temperature is when low, the heat exchange effect that then is serially connected with each heat exchanger in the boiler smoke passage obviously reduces, and does not have the due effect of each heat exchanger.
In addition, thermal power plant is in order to prevent the air preheater cold end corrosion, particularly for cold district, cold air duct before air preheater is provided with a steam air heater, warm-air drier heats the air that enters air preheater in advance by drawing gas of steam turbine, promptly arranges the vapour-gas heat exchanger in cold air duct.In such cases,, make the air themperature that enters boiler increase, thereby improved boiler efficiency,, reduced generating capacity, take all factors into consideration, reduced economic benefit because employing is that the steam turbine high-grade is drawn gas although improved the cold air temperature.
Summary of the invention
Technical problem to be solved in the utility model provides a kind of power plant boiler flue gas waste heat recovery and utilizes system, and native system has effectively improved the efficient that residual heat from boiler fume is recycled, and improved the heat exchange effect of heat exchanger and boiler, Efficiency of Steam Turbine.
For solving the problems of the technologies described above, especially air side and fume side exchange heat asymmetric in the air preheater, the power plant boiler flue gas waste heat recovery utilizes system to comprise boiler, blower fan, air preheater, deduster, air-introduced machine, booster fan, desulfurizing tower, chimney, steam turbine and heat regenerative system, described heat regenerative system comprises condenser, the high pressure condensate water heater of several serial connections and low pressure condensate water heater, described Boiler Steam output connects described steam turbine steam input, steam turbine condensate water output connects described heat regenerative system input, described heat regenerative system output connects described boiler condensate water input, described blower fan output, air preheater air input be connected described boiler air input after output is connected successively, described air preheater, deduster, air-introduced machine, after connecting successively, the flue gas input/output terminal of booster fan and desulfurizing tower is connected described boiler smoke output and chimney smoke input respectively, native system also comprises first heat exchanger, the first flow control valve and second flow control valve, the flue gas input of described first heat exchanger connects the flue gas input of described air preheater, the flue gas output of described first heat exchanger connects the flue gas output of described air preheater, the heat transferring medium input of described first heat exchanger, output is connected the input of described arbitrary high pressure condensate water heater respectively with second flow control valve by described first flow control valve, output.
Further, for improving the heat exchange effect, native system also comprises to the water-to-water heat exchanger and first circulating pump, the heat transferring medium input of described first heat exchanger, output connect described heat transferring medium input, the output of giving water-to-water heat exchanger, the described feedwater input of water-to-water heat exchanger, output is connected described arbitrary high pressure condensate water heater respectively with second flow control valve by described first flow control valve input, the output given by described first circulating pump.
Further, native system also comprises second heat exchanger, the 3rd flow control valve and the 4th flow control valve, the flue gas input/output terminal of described second heat exchanger is serially connected with between described air-introduced machine output and the booster fan input, the heat transferring medium input of described second heat exchanger connects the input of described arbitrary low pressure condensate water heater by described the 3rd flow control valve, and the heat transferring medium output of described second heat exchanger connects the output of described arbitrary low pressure condensate water heater by described the 4th flow control valve.
Further, native system also comprises the 3rd heat exchanger, the air heater and second circulating pump, the flue gas input/output terminal of described the 3rd heat exchanger is serially connected with between described booster fan output and the desulfurizing tower input, the air input/output terminal of described air heater is serially connected with between described blower fan output and the air preheater air input, the heat transferring medium output of described the 3rd heat exchanger connects the heat transferring medium input of described air heater by described second circulating pump, and the heat transferring medium output of described air heater connects the heat transferring medium input of described the 3rd heat exchanger.
Further, native system also comprises the 4th heat exchanger, flue gas heater and the 3rd circulating pump, the flue gas input/output terminal of described the 4th heat exchanger is serially connected with between the flue gas input of the flue gas output of described the 3rd heat exchanger and desulfurizing tower, the flue gas input/output terminal of described flue gas heater is serially connected with between the flue gas output and chimney smoke input of described desulfurizing tower, described the 4th heat exchanger heat transferring medium output connects the heat transferring medium input of described flue gas heater by described the 3rd circulating pump, and the heat transferring medium output of described flue gas heater connects the heat transferring medium input of described the 4th heat exchanger.
Further, handling for improving native system, be provided with gas bypass by three air-valves respectively between the flue gas input/output terminal of above-mentioned second heat exchanger, two air-valves are located at the flue gas input and the output of described second heat exchanger respectively in described three air-valves, and an air-valve is located on the above-mentioned gas bypass in described three air-valves.
Be provided with the cold wind bypass by three air-valves between the air input/output terminal of above-mentioned air heater, two air-valves are located at the air input and the output of air heater respectively in described three air-valves, an air-valve is located in the cold wind bypass in described three air-valves, be provided with gas bypass by three air-valves respectively between the flue gas input/output terminal of described first heat exchanger and the 3rd heat exchanger, two air-valves are located at the flue gas input and the output of described first heat exchanger and the 3rd heat exchanger respectively in described three air-valves, and an air-valve is located at respectively on above-mentioned each gas bypass in described three air-valves.
Be provided with gas bypass by three air-valves respectively between the flue gas input/output terminal of above-mentioned the 4th heat exchanger, flue gas heater, two air-valves are located at the flue gas input and the output of described the 4th heat exchanger, flue gas heater respectively in described three air-valves, and an air-valve is located at respectively on above-mentioned each gas bypass in described three air-valves.
Connect and setting for convenient, the flue gas input/output terminal of the first above-mentioned heat exchanger can be series in the flue of described boiler and air preheater.
The flue gas input/output terminal of the second above-mentioned heat exchanger can connect the flue gas output of described air preheater and the input of deduster.
The flue gas input/output terminal of above-mentioned the 4th heat exchanger can connect the flue gas output of described second heat exchanger and the flue gas input of booster fan.
For ease of the control of native system heat exchange effect, the thermal change of above-mentioned air heater can be realized by the changes in flow rate of regulating circulatory mediator by second circulating pump.
The thermal change of above-mentioned flue gas heater can be realized by the changes in flow rate of regulating circulatory mediator by the 3rd circulating pump.
Because the flue gas waste heat recovery of the utility model power plant boiler utilizes system to adopt technique scheme, promptly at flue gas input, output first heat exchanger in parallel of the exhaust gases passes air preheater of boiler, the heat transferring medium input/output terminal of first heat exchanger connects the input/output terminal of arbitrary high pressure condensate water heater respectively by flow control valve, and heating is through the condensate water of high pressure condensate water heater; Native system has effectively improved the efficient that residual heat from boiler fume is recycled, and has improved the heat exchange effect of heat exchanger and boiler, Efficiency of Steam Turbine.
Description of drawings
The utility model is described in further detail below in conjunction with drawings and embodiments:
Fig. 1 is the connection diagram of power plant boiler flue gas smoke evacuation,
Fig. 2 is the connection diagram that the flue gas waste heat recovery of the utility model power plant boiler utilizes system,
Fig. 3 adds connection diagram to water-to-water heat exchanger for native system,
Fig. 4 adds the connection diagram of other heat exchangers for native system,
Fig. 5 adds the connection diagram of cold wind bypass and gas bypass for native system.
The specific embodiment
As shown in Figure 2, the flue gas waste heat recovery of the utility model power plant boiler utilizes system to comprise boiler 10, blower fan 11, air preheater 12, deduster 13, air-introduced machine 14, booster fan 15, desulfurizing tower 16, chimney 17, steam turbine 20 and heat regenerative system 22, described heat regenerative system 22 comprises condenser 23, the high pressure condensate water heater 24 and the low pressure condensate water heater 25 of several serial connections, described boiler 10 steam output ends connect described steam turbine 20 steam inputs, steam turbine 20 condensate water outputs connect described heat regenerative system 22 inputs, described heat regenerative system 22 outputs connect described boiler 10 condensate water inputs, described blower fan 11 outputs, air preheater 12 air inputs be connected described boiler 10 air inputs after output is connected successively, described air preheater 12, deduster 13, air-introduced machine 14, after connecting successively, the flue gas input/output terminal of booster fan 15 and desulfurizing tower 16 is connected described boiler 10 flue gas outputs and chimney 17 flue gas inputs respectively, native system also comprises first heat exchanger 5, the first flow control valve 51 and second flow control valve 52, the flue gas input of described first heat exchanger 5 connects the flue gas input of described air preheater 12, the flue gas output of described first heat exchanger 5 connects the flue gas output of described air preheater 12, the heat transferring medium input of described first heat exchanger 5, output is connected the input of described arbitrary high pressure condensate water heater 24 respectively with second flow control valve 52 by described first flow control valve 51, output.
As shown in Figure 3, further, for improving the heat exchange effect, native system also comprises to the water-to-water heat exchanger 7 and first circulating pump 71, the heat transferring medium input of described first heat exchanger 5, output connect described heat transferring medium input, the output of giving water-to-water heat exchanger 7, the described feedwater input of water-to-water heat exchanger 7, output is connected described arbitrary high pressure condensate water heater 24 respectively with second flow control valve 52 by described first flow control valve 51 input, the output given by described first circulating pump 71.
As shown in Figure 4, further, native system also comprises second heat exchanger 3, the 3rd flow control valve 31 and the 4th flow control valve 32, the flue gas input/output terminal of described second heat exchanger 3 is serially connected with between described air-introduced machine 14 outputs and booster fan 15 inputs, the heat transferring medium input of described second heat exchanger 3 is by the input of the described arbitrary low pressure condensate water heater 25 of described the 3rd flow control valve 31 connections, and the heat transferring medium output of described second heat exchanger 3 connects the output of described arbitrary low pressure condensate water heater 25 by described the 4th flow control valve 32.
As shown in Figure 4, further, native system also comprises the 3rd heat exchanger 4, the air heater 6 and second circulating pump 61, the flue gas input/output terminal of described the 3rd heat exchanger 4 is serially connected with between described booster fan 15 outputs and desulfurizing tower 16 inputs, the air input/output terminal of described air heater 6 is serially connected with between described blower fan 11 outputs and the air preheater 12 air inputs, the heat transferring medium output of described the 3rd heat exchanger 4 is by the heat transferring medium input of the described air heater 6 of described second circulating pump, 61 connections, and the heat transferring medium output of described air heater 6 connects the heat transferring medium input of described the 3rd heat exchanger 4.
As shown in Figure 4, further, native system also comprises the 4th heat exchanger 81, flue gas heater 82 and the 3rd circulating pump 83, the flue gas input/output terminal of described the 4th heat exchanger 81 is serially connected with between the flue gas input of the flue gas output of described the 3rd heat exchanger 4 and desulfurizing tower 16, the flue gas input/output terminal of described flue gas heater 82 is serially connected with between the flue gas output and chimney 17 flue gas inputs of described desulfurizing tower 17, described the 4th heat exchanger 81 heat transferring medium outputs are by the heat transferring medium input of the described flue gas heater 82 of described the 3rd circulating pump 83 connections, and the heat transferring medium output of described flue gas heater 82 connects the heat transferring medium input of described the 4th heat exchanger 81.
As shown in Figure 5, further, handling for improving native system, be provided with gas bypass 92 by three air-valves 9 respectively between the flue gas input/output terminal of above-mentioned second heat exchanger 3, two air-valves are located at the flue gas input and the output of described second heat exchanger 3 respectively in described three air-valves 9, and an air-valve is located on the above-mentioned gas bypass 92 in described three air-valves 9.
As shown in Figure 5, be provided with cold wind bypass 91 by three air-valves 9 between the air input/output terminal of above-mentioned air heater 6, two air-valves are located at the air input and the output of air heater 6 respectively in described three air-valves 9, an air-valve is located in the cold wind bypass 91 in described three air-valves 9, be provided with gas bypass 92 by three air-valves 9 respectively between the flue gas input/output terminal of described first heat exchanger 5 and the 3rd heat exchanger 4, two air-valves are located at the flue gas input and the output of described first heat exchanger 5 and the 3rd heat exchanger 4 respectively in described three air-valves 9, and an air-valve is located at respectively on above-mentioned each gas bypass 92 in described three air-valves 9.
As shown in Figure 5, be provided with gas bypass 92 by three air-valves 9 respectively between the flue gas input/output terminal of above-mentioned the 4th heat exchanger 81, flue gas heater 82, two air-valves are located at the flue gas input and the output of described the 4th heat exchanger 81, flue gas heater 82 respectively in described three air-valves 9, and an air-valve is located at respectively on above-mentioned each gas bypass 92 in described three air-valves 9.
Connect and setting for convenient, the flue gas input/output terminal of the first above-mentioned heat exchanger 5 can be series in the flue of described boiler 10 and air preheater 12.
The flue gas input/output terminal of the second above-mentioned heat exchanger 3 can connect the flue gas output of described air preheater 12 and the input of deduster 13.
The flue gas input/output terminal of above-mentioned the 4th heat exchanger 81 can connect the flue gas output of described second heat exchanger 3 and the flue gas input of booster fan 15.
For ease of the control of native system heat exchange effect, the thermal change of above-mentioned air heater 6 can be realized by the changes in flow rate of regulating circulatory mediator by second circulating pump 61.
The thermal change of above-mentioned flue gas heater 82 can be realized by the changes in flow rate of regulating circulatory mediator by the 3rd circulating pump 83.
Because flue-gas temperature reduces step by step in the boiler smoke passage, therefore second heat exchanger that is serially connected with the exhaust gases passes rear end is connected low pressure condensate water heater and air heater respectively with the 3rd heat exchanger, be used for relatively low low pressure condensate water of heating-up temperature and the air that enters boiler, to improve the efficient of steam turbine and boiler, reduce low pressure condensate water heater drawing gas to steam turbine; The air heater of the 3rd heat exchanger connection simultaneously heats the cold end corrosion that the air that enters boiler has also been avoided air preheater, the service life of having improved air preheater; The 4th heat exchanger and flue gas heater be provided for heating the flue-gas temperature that enters chimney, improved the smoke evacuation height of chimney, be beneficial to environmental protection, reduced the corrosion of flue gas simultaneously to chimney; First heat exchanger is parallel to flue gas input, the output of air preheater, and by flow control valve connection high pressure condensate water heater, first heat exchanger is arranged at first section of boiler smoke passage, the flue-gas temperature of its acquisition is higher relatively, therefore can be used for the heating high-pressure condensate water, reduce high pressure condensate water heater drawing gas to steam turbine, and the steam turbine steam that high pressure condensate water heater uses is high-quality steam, reduces drawing gas of high-quality steam and makes Efficiency of Steam Turbine obtain further raising.Native system effective recycling residual heat from boiler fume improves boiler and turbine work efficient, obtains good economic benefit and social benefit.