CN104976610A - Medium-temperature coal economizer system and method thereof for recovering smoke afterheat - Google Patents
Medium-temperature coal economizer system and method thereof for recovering smoke afterheat Download PDFInfo
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Abstract
The invention provides a medium-temperature coal economizer system. The medium-temperature coal economizer system comprises at least one smoke-water heat exchange device, a first flue and a second flue, wherein a smoke inlet of the smoke-water heat exchange device and a flue in an inlet of an air preheater are connected through the first flue; a smoke outlet of the smoke-water heat exchange device and a flue in an outlet of the air preheater are connected through the second flue; and the medium-temperature coal economizer system further comprises a heat exchange device for heating inlet air of the air preheater. The medium-temperature coal economizer system, provided by the invention, shunts part smoke in the inlet of the air preheater, heats water in the smoke-water heat exchange device, heats the inlet air of the air preheater through an air-steam/water heat exchange device, can recover the smoke afterheat, can reduce the smoke temperature, can satisfy the requirement of lowering the smoke temperature in the inlet of a low-temperature dust remover, can improve the dust removing efficiency, and can prevent such problems as low-temperature corrosion and blockage at a cold end of the air preheater. The invention further provides a method for recovering the smoke afterheat by adopting the medium-temperature coal economizer system.
Description
Technical field
The invention belongs to firepower Thermal generation unit field, be specifically related to a kind ofly be applied to the middle temperature economizer system in thermal power plant and the method for Mist heat recovering thereof.
Background technology
The flue of tradition power plant units before air preheater is configured with high-temperature economizer, namely the flue gas heat of boiler is utilized to carry out heated feed water, absorption flue gas heat can be played improve boiler efficiency, improve the effects such as the feed temperature of water-cooling wall, along with improving constantly of the environmental requirements such as energy-saving and emission-reduction, part power plant units also can at follow-up flue configuration ' cigarette-water ' heat exchanger of boiler air preheater, namely the flue gas heat after boiler air preheater is utilized to come heat-setting water or hot net water etc., with recovered flue gas heat, reduce exhaust gas temperature.Due to relative to high-temperature economizer, should ' cigarette-water ' heat exchanger entrance flue-gas temperature low, be thus also called low-level (stack-gas) economizer.
Low cold precipitator refers to that deduster entrance flue gas temperature is below boiler design exhaust gas temperature, and minimum temperature meets the deduster of wet desulfurization system technological temperature requirement.For coordinating the use of low cold precipitator, promoting efficiency of dust collection, is generally arrange low-level (stack-gas) economizer before deduster, to reduce deduster import cigarette temperature.
But, for built power plant, often there is deduster inlet flue duct short and small narrow, be difficult to the problem of arranging low-level (stack-gas) economizer.In addition, what the heat that low-level (stack-gas) economizer reclaims squeezed is that steam turbine low-pressure draws gas, and quality is lower, and economy is not good enough.
In history, the flue gas waste heat recovery technology that Germany once adopted a kind of organic efficiency higher, namely at the bypass flue of air preheater fume side one built-in ' cigarette-water ' heat exchanger in parallel, Qi Shui side is that the partial high pressure distributed from feed water circuit feeds water and part low pressure feed water, the heat energy of flue gas draws gas with high, the middle pressure of alternative steam turbine in order to heat this part feedwater, thus reduces the steam turbine steam consumption and hear rate.The heat energy quality that this smoke heat energy recovery method reclaims, far above low-level (stack-gas) economizer system, thus has higher smoke heat energy organic efficiency.But, this technology is only applicable to the too high boiler of exhaust gas temperature, as boiler using brown coal.This is because after the flue gas of air preheater is shunted, its exhaust gas temperature must decline.For the normal boiler of former exhaust gas temperature, if its exhaust gas temperature is declined further, air preheater low temperature side heat exchanger fin mean wall temperature is caused to drop to below design load, the risk that its sulfuric acid condensation, corrosion and heat-transfer surface must be caused to block sharply increases, lose more than gain, therefore current this technology no longer adopts on the newly-built unit of Germany.
Therefore, those skilled in the art is devoted to study how under the condition ensureing unit safety operation, can realize energy-conservation by the waste heat in the recovery boiler tail flue gas of relative efficiency, simultaneously again can in low air preheater outlet cigarette temperature of avoiding that air preheater low temperature side condenses, the prerequisite of Corrosion blockage declines, meet the requirement of low cold precipitator import cigarette temperature, improve efficiency of dust collection.
Summary of the invention
For the problems referred to above, the invention provides a kind of system, under the condition ensureing unit safety operation, can waste heat in the recovery boiler tail flue gas of relative efficiency, reach energy-conservation object, simultaneously in low air preheater outlet cigarette temperature of avoiding that air preheater low temperature side condenses, the prerequisite of Corrosion blockage declines, the requirement of low cold precipitator import cigarette temperature can be met again, improve efficiency of dust collection, thus the safe, energy-conservation of unit and environmental protection can be taken into account.
System provided by the invention, for high-temperature economizer and low-level (stack-gas) economizer, ' cigarette-water ' flue-gas temperature of heat-exchanger rig of setting up, generally at 90-370 DEG C, between high-temperature economizer and low-level (stack-gas) economizer, therefore also can be referred to as " middle temperature economizer system ".
The invention provides warm economizer system in one, comprise at least one ' cigarette-water ' heat-exchanger rig, the first flue and second flue, it is characterized in that, the mouth that enters of ' cigarette-water ' heat-exchanger rig is connected by the first flue with the flue of air preheater import department, the outlet flue of ' cigarette-water ' heat-exchanger rig is connected by the second flue with the flue in air preheater exit, and middle temperature economizer system also comprises the heat-exchanger rig of heating air preheater air intake.
Middle temperature economizer system provided by the invention is the flue splitter section flue gas in air preheater import department, and for the water in heating ' cigarette-water ' heat-exchanger rig, water is back to therrmodynamic system after absorbing flue gas heat again, thus improves the economy of unit.
Middle temperature economizer system provided by the invention, middle temperature economizer system flue is formed in parallel with the cigarette side of air preheater, the partial fume that air preheater gas approach is shunted is entered middle temperature economizer system flue, the flue gas flow of unit air preheater cigarette side is declined, and flue resistance and flue gas flow are declined to become quadratic relationship declines; In addition, the flue-gas temperature of air preheater outlet declines, and the corresponding decline of flue gas volume flow, follow-up flue gas resistance can be also that quadratic relationship declines with flue gas volume flow.Therefore, whole unit cigarette side system resistance will obviously decline, and this discharges certain allowance for unit cigarette crosswind machine.
The flue gas of air preheater import department shunting enters middle temperature economizer system, is progressively cooled; Because part of smoke enters middle temperature economizer system, the exhaust gas volumn entering air preheater can decline, and air preheater intake does not change, although air preheater EAT can have suitable lifting because of the heat-exchanger rig of heating boiler air intake, but still the flue-gas temperature that can control air preheater outlet declines.The flue-gas temperature that the flue gas of middle temperature economizer system outlet and air preheater export all is reduced, and then collects and enters deduster, thus improve efficiency of dust collection.Meanwhile, because air preheater EAT is by ' wind-vapour ' heat-exchanger rig or the heating of ' wind-water ' heat-exchanger rig, the wind-warm syndrome entering air preheater rises, as long as guarantee that the mean temperature of air preheater cold-end air wind side now and cigarette side is equal to or higher than former design load, just can guarantee that the heat exchanger fin surface of its cold junction does not occur condensation, corrosion and blocks when exhaust gas temperature declines.
Therefore middle temperature economizer system provided by the invention, under the condition ensureing air preheater safe operation, can waste heat in recovery boiler tail flue gas, reach energy-conservation object, cigarette temperature can be reduced again, meet the requirement of low cold precipitator import cigarette temperature, improve efficiency of dust collection.Thus reach the object taking into account safe, energy-conservation and environmental protection.
Further, inlet porting gas baffle in the first flue.
Middle temperature economizer system provided by the invention, the flue of middle temperature economizer system is in parallel with air preheater cigarette side, regulates the exhaust gas volumn entering ' cigarette-water ' heat-exchanger rig by inlet flue gas baffle plate; With warm economizer system in meeting in the service requirement of the different operating mode of unit, improve system cloud gray model economy.
If middle temperature economizer system breaks down, by closing inlet flue gas baffle plate, cut off the flue gas entering middle temperature economizer system.
Further, in the second flue, outlet gas baffle is set.
If middle temperature economizer system breaks down, the inlet flue gas baffle plate in the first flue and the exiting flue gas baffle plate in the second flue can be closed, warm economizer system fume side in completely cutting off.
Further, ' cigarette-water ' heat-exchanger rig water side water inlet arranges barrier valve.
Adopt middle temperature economizer system provided by the invention, if middle temperature economizer system breaks down, by closing the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side water inlet, warm economizer system water side in cut-out.
Further, ' cigarette-water ' heat-exchanger rig water side delivery port arranges barrier valve.
Adopt middle temperature economizer system provided by the invention, if middle temperature economizer system breaks down, by closing the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side delivery port, warm economizer system water side in cut-out.
Adopt middle temperature economizer system provided by the invention, if middle temperature economizer system breaks down, by closing the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side water inlet and delivery port, warm economizer system water side in excision simultaneously.
Further, the water side of ' cigarette-water ' heat-exchanger rig arranges control valve, enters the water yield of ' cigarette-water ' heat-exchanger rig, thus control water temperature for regulating, and with warm economizer system in meeting in the service requirement of the different operating mode of unit, improves system cloud gray model economy.
Further, ' cigarette-water ' heat-exchanger rig is one.
Further, ' cigarette-water ' heat-exchanger rig is multiple.
Further, the flue of multiple ' cigarette-water ' heat-exchanger rig connects successively, the mouth that enters of first ' cigarette-water ' heat-exchanger rig is connected by the first flue with the flue of air preheater import department, and the outlet flue of last ' cigarette-water ' heat-exchanger rig is connected by the second flue with the flue in air preheater exit.
Water side water inlet, the water side delivery port of multiple ' cigarette-water ' heat-exchanger rig are connected with high-pressure feed water system, condensate system respectively by pipeline.Mutually connect between multiple cigarette-water heat-exchanger rig fume side, the flue gas entering middle temperature economizer system heats the water flowing through multiple ' cigarette-water ' heat-exchanger rig connected successively successively, thus progressively reduce flue-gas temperature, realize fume afterheat step to recycle, and improve the efficiency of dust collection of deduster.
Further, the heat-exchanger rig of heating air preheater air intake is ' wind-vapour ' heat-exchanger rig, and the air side of ' wind-vapour ' heat-exchanger rig connects air preheater air intake, and the vapour side of ' wind-vapour ' heat-exchanger rig connects steam.Thermal source is steam, for heating air intake, can heat cold First air, also can heat cold Secondary Air, can also heat cold First air and cold Secondary Air simultaneously.
Further, steam is extracted steam from turbine or auxiliary vapour.
Further, steam is the water vapour higher than 100 DEG C.
Further, the heat-exchanger rig of heating air preheater air intake is ' wind-water ' heat-exchanger rig, and the air side of ' wind-water ' heat-exchanger rig connects air preheater air intake, and the water side of ' wind-water ' heat-exchanger rig connects hot water.Thermal source is hot water, for heating air intake, can heat cold First air, also can heat cold Secondary Air, can also heat cold First air and cold Secondary Air simultaneously.
Further, hot water is heat supply network backwater or low-level (stack-gas) economizer backwater.
Hot water is the hot water higher than 50 DEG C.
If without installing ' wind-vapour/water ' heat-exchanger rig and only have ' cigarette-water ' heat-exchanger rig, air preheater outlet cigarette temperature can corresponding reduction, causes air preheater cold junction mean temperature to reduce, causes the risk of cold end corrosion and blocking sharply to increase.Install ' wind-vapour/water ' heat-exchanger rig additional, in order to heat the air intake of air preheater, promote air preheater entrance wind-warm syndrome, thus the comprehensive mean temperature of Integral lifting air preheater cold junction, avoid the problems such as the cold end corrosion of air preheater cold junction and blocking.
Further, the wind side of heat-exchanger rig connects air preheater air intake, the thermal source quality that heat-exchanger rig uses lower than the quality recovered energy, to guarantee the raising of economy.
The present invention also provides a kind of method adopting middle temperature economizer system Mist heat recovering provided by the invention, comprises the following steps:
(1) at the flue splitter section flue gas of air preheater import department, the flue gas distributed enters middle temperature economizer system, heat-exchanger rig heating air preheater air intake;
(2) flue gas distributed flows through the water of ' cigarette-water ' heat-exchanger rig of middle temperature economizer system, and water absorbs heat and returns therrmodynamic system again, with Mist heat recovering;
(3) in air preheater exit, the flue gas that the flue gas distributed and air preheater export collects.
The method of Mist heat recovering provided by the invention, at the flue of air preheater import department, splitter section flue gas, the flue gas of shunting flows through the water of ' cigarette-water ' heat-exchanger rig, reclaim fume afterheat, decrease high, the middle pressure of steam turbine to draw gas, reduce the steam consumption of steam turbine and hear rate, improve the economy of unit, reach energy-conservation object.
The method of Mist heat recovering provided by the invention, at the flue splitter section flue gas of air preheater import department, makes the flue gas flow of air preheater cigarette side decline, and flue resistance and flue gas flow are declined to become quadratic relationship declines; In addition, the flue-gas temperature of air preheater outlet declines, and the corresponding decline of flue gas volume flow, follow-up flue resistance can be also that quadratic relationship declines with flue gas volume flow.Therefore, whole unit cigarette side system resistance will obviously decline, and this is that unit cigarette crosswind machine discharges certain allowance.
The method of Mist heat recovering provided by the invention, the flue-gas temperature entering electric cleaner is declined, and flow velocity declines, and the sedimentation rate of flue dust rises; Flue gas residence time increases; Flue dust ratio resistance declines; Twice carrying rate of flue gas to flue dust in electric precipitation exit declines, thus improves efficiency of dust collection.
Therefore the method for Mist heat recovering provided by the invention, under the condition ensureing air preheater safe operation, can waste heat in recovery boiler tail flue gas, reach energy-conservation object, cigarette temperature can be reduced again, meet the requirement of low cold precipitator import cigarette temperature, improve efficiency of dust collection.
Further, the method for Mist heat recovering also comprises adjustment gas baffle, controls the exhaust gas volumn that shunting enters cigarette-water heat-exchanger rig, thus the requirement of warm economizer under the different operating mode of unit is run in meeting, improve system cloud gray model economy.
Further, when central temperature economizer system breaks down, close inlet flue gas baffle plate, to cut off the flue gas entering middle temperature economizer system.
If middle temperature economizer system breaks down, inlet flue gas baffle plate, exiting flue gas baffle plate can be closed, the isolated flue gas entering middle temperature economizer system, thus warm economizer system fume side in cutting off.
Therefore the method for Mist heat recovering provided by the invention, can under the condition ensureing unit safety operation, and the waste heat in recovery boiler tail flue gas, reaches energy-conservation object.
Further, the method for Mist heat recovering also comprises the control valve that adjustment is arranged at ' cigarette-water ' heat-exchanger rig water side, and control flow check is through the water yield of ' cigarette-water ' heat-exchanger rig.
Adopt the method for Mist heat recovering provided by the invention, can be regulated by control valve and enter the water yield of ' cigarette-water ' heat-exchanger rig, control water temperature, with warm economizer system in meeting in the service requirement of the different operating mode of unit, improve system cloud gray model economy.
Further, when central warm economizer system breaks down, the barrier valve of closedown is arranged at ' cigarette-water ' heat-exchanger rig water side water inlet, or close the barrier valve being arranged at ' cigarette-water ' heat-exchanger rig water side delivery port, or close the barrier valve being arranged at ' cigarette-water ' heat-exchanger rig water side import and export, with the isolated water entering ' cigarette-water ' heat-exchanger rig simultaneously.
Adopt the method for Mist heat recovering provided by the invention, if middle temperature economizer system breaks down, the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side water inlet or delivery port can be closed separately, also can close the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side water inlet and the barrier valve being arranged on ' cigarette-water ' heat-exchanger rig water side delivery port simultaneously, even if having one to break down in two barrier valves, still the water entering middle temperature economizer system can be completely cut off, thus the water side of warm economizer system in cutting off.
Further, heat air preheater air intake comprise the cold First air of heating air preheater, the heating cold Secondary Air of air preheater or heat the cold First air of air preheater and cold Secondary Air simultaneously.
Adopt the method for Mist heat recovering provided by the invention, because middle temperature economizer system has shunted partial fume, air preheater outlet cigarette temperature can reduce, and especially for the unit installing denitrification apparatus, its air preheater cold-end air easily condenses and blocks.For this reason, before air preheater air intake, utilize ' wind-vapour/water ' heat exchanger to heat air intake, improve air preheater entrance wind-warm syndrome, thus the comprehensive mean temperature of Integral lifting air preheater cold-end air, avoid air preheater cold-end air cold end corrosion and blocking.
Therefore the method for Mist heat recovering provided by the invention, can under the condition ensureing unit safety operation, and the waste heat in recovery boiler tail flue gas, reaches energy-conservation object.
Further, heat-exchanger rig adopts ' wind-vapour ' heat-exchanger rig, and thermal source is steam.
Further, steam is the auxiliary vapour of unit or extracted steam from turbine.
Further, steam is the water vapour higher than 100 DEG C.
Further, heat-exchanger rig adopts ' wind-water ' heat-exchanger rig, and thermal source is hot water.
Further, hot water is heat supply network backwater or low-level (stack-gas) economizer backwater.
Further, hot water is the hot water higher than 50 DEG C.
Further, heat-exchanger rig use thermal source quality lower than the quality recovered energy, to guarantee the raising of economy.
Be described further below with reference to the technique effect of accompanying drawing to design of the present invention, concrete structure and generation, to understand object of the present invention, characteristic sum effect fully.
Accompanying drawing explanation
Fig. 1 is the principle schematic of the middle temperature economizer system of one embodiment of the present of invention;
Fig. 2 is the schematic diagram that the middle temperature economizer system shown in Fig. 1 comprises the connection of water side.
Detailed description of the invention
Fig. 1 is the schematic diagram of the middle temperature economizer system of one embodiment of the present of invention, as shown in Figure 1, unit comprises boiler 1, denitrification apparatus 2, air preheater 3, deduster 4, induced-draught fan 5 and chimney 6, and middle temperature economizer system comprises entrance gas baffle 7, ' cigarette-water ' heat-exchanger rig 81,82 and heat-exchanger rig 9.
Middle temperature economizer system in the present embodiment comprises two ' cigarette-water ' heat-exchanger rigs 81,82, the mouth that enters of ' cigarette-water ' heat-exchanger rig 81 is connected by the first flue with the flue of air preheater 3 import department, the outlet flue of ' cigarette-water ' heat-exchanger rig 81 is connected by flue with the mouth that enters of ' cigarette-water ' heat-exchanger rig 82, and the outlet flue of water heat-exchanger rig 82 is connected by the second flue with the flue in air preheater 3 exit.
Water side water inlet, the water side delivery port of ' cigarette-water ' heat-exchanger rig 81,82 connect unit high-pressure feed water system and condensate system respectively by pipeline.
Enter the flue gas of the middle temperature economizer system in the present embodiment, heating flows through the high-pressure feed water of ' cigarette-water ' heat-exchanger rig 81 and flows through the condensate water of ' cigarette-water ' heat-exchanger rig 82 successively, thus progressively reduce flue-gas temperature, realize fume afterheat step to recycle, and improve the efficiency of dust collection of deduster.
Heat-exchanger rig 9 is for heating air preheater 3 air intake.
The flue gas of air preheater 3 import department shunting enters middle temperature economizer system, is progressively cooled; Because part of smoke enters middle temperature economizer system, the exhaust gas volumn entering air preheater 3 can decline, and air preheater 3 intake does not change, although air preheater 3 EAT can have suitable lifting because of the heat-exchanger rig of heating boiler air intake, but still the flue-gas temperature that can control air preheater 3 outlet declines.The flue-gas temperature that the flue gas of middle temperature economizer system outlet and air preheater 3 export all is reduced, and then collects and enters deduster 4, thus improve efficiency of dust collection.
If without installing heat-exchanger rig 9 and only have ' cigarette-water ' heat-exchanger rig 81,82, air preheater 3 exports cigarette temperature can corresponding reduction, causes air preheater 3 cold junction mean temperature to reduce, causes the risk of cold end corrosion and blocking sharply to increase.Install heat-exchanger rig 9 additional, the wind-warm syndrome entering air preheater 3 rises, as long as guarantee that the mean temperature of air preheater 3 cold junction wind side now and cigarette side is equal to or higher than former design load, just can guarantee that the heat exchanger fin surface of its cold junction does not occur condensation, corrosion and blocks when exhaust gas temperature declines.
Middle temperature economizer system in the present embodiment, under the condition ensureing air preheater safe operation, can waste heat in recovery boiler tail flue gas, reach energy-conservation object, cigarette temperature can be reduced again, meet the requirement of low cold precipitator import cigarette temperature, improve efficiency of dust collection.Thus reach the object taking into account safe, energy-conservation and environmental protection.
Inlet flue gas baffle plate 7 is for controlling the exhaust gas volumn entering middle temperature economizer system.
Middle temperature economizer system in the present embodiment, the flue of middle temperature economizer system is in parallel with air preheater cigarette side, can control the exhaust gas volumn entering middle temperature economizer system by inlet flue gas baffle plate 7; With warm economizer system in meeting in the service requirement of the different operating mode of unit, improve system cloud gray model economy.
When central warm economizer system breaks down, close inlet flue gas baffle plate 7, to cut off the flue gas entering middle temperature economizer system.
Middle temperature economizer system in the present embodiment, can also arrange outlet gas baffle at the second flue.
If middle temperature economizer system breaks down, the inlet flue gas baffle plate 7 of bypass flue, exiting flue gas baffle plate can be closed, with warm economizer system fume side in isolated.
As shown in Figure 2, ' cigarette-water ' heat-exchanger rig 81 is connected with the high-pressure feed water system 11 of unit, the water side water inlet of ' cigarette-water ' heat-exchanger rig 82 is connected with the water side water inlet of the condensate water of secondary low-voltage heater 22, and the water side delivery port of ' cigarette-water ' heat-exchanger rig 82 is connected with the water side delivery port of the condensate water of final stage low-pressure heater 21.
The flue gas distributed heats high-pressure feed water, the condensate water of extracting out from unit high-pressure feed water, condensate system successively, and the high-pressure feed water after heating, condensate water return former therrmodynamic system respectively again, and flue gas is then cooled by progressively classification.' cigarette-water ' heat-exchanger rig 81 be wherein connected with high-pressure feed water system is called middle temperature high-pressure economizer, ' cigarette-water ' heat-exchanger rig 82 be connected with condensate system is called middle temperature low-pressure coal saver.
The water side ducts of ' cigarette-water ' heat-exchanger rig 81 is in parallel with the pipeline of high-pressure feed water system 11, the water side ducts of ' cigarette-water ' heat-exchanger rig 82 is in parallel with the pipeline of condensate system 21,22, thus pipe-line system resistance all can decline, thus can reduce the operation power consumption of corresponding water pump, thus improve the economy of whole unit.
The water side water inlet of ' cigarette-water ' heat-exchanger rig 81,82 arranges control valve 811,821, the water yield entering ' cigarette-water ' heat-exchanger rig 81,82 can be controlled by control valve 811,821, thus control water temperature, with warm economizer system in meeting in the service requirement of the different operating mode of unit, improve system cloud gray model economy.
Middle temperature economizer system in the present embodiment, can by inlet flue gas baffle plate 7 and control valve 811,821, control to enter exhaust gas volumn and the water yield of middle temperature economizer system, control air preheater 3 by the adjustment of exhaust gas volumn, the water yield and export cigarette temperature, the balance of middle temperature economizer system outlet cigarette temperature and mixed comprehensive cigarette temperature.
By the adjustment of exhaust gas volumn, the water yield, also the temperature of the water flowing through ' cigarette-water ' heat-exchanger rig 81,82 can be regulated, thus means of feed temperature are controlled under also can be used as unit underload, the feed temperature under underload can be promoted to a certain extent, certain positive role is played to dropping into denitration operation under underload, decrease water-cooling wall entrance simultaneously and owe enthalpy, be conducive to hydrodynamic stable.
The water side water inlet of ' cigarette-water ' heat-exchanger rig 81,82 arranges barrier valve 812,822, adopt middle temperature economizer system provided by the invention, if middle temperature economizer system breaks down, the barrier valve 812,822 of the water side water inlet being arranged on ' cigarette-water ' heat-exchanger rig 81,82 can be closed, the water side of warm economizer system in cut-out.
The water side delivery port of ' cigarette-water ' heat-exchanger rig 81,82 arranges barrier valve 813,823, adopt middle temperature economizer system provided by the invention, if middle temperature economizer system breaks down, the barrier valve 813,823 of the water side delivery port being arranged on ' cigarette-water ' heat-exchanger rig 81,82 can be closed, the water side of warm economizer system in cut-out; Also can close the barrier valve 812,822 being arranged on ' cigarette-water ' heat-exchanger rig water side delivery port and the barrier valve 813,823 being arranged on ' cigarette-water ' heat-exchanger rig water side delivery port simultaneously, thus the water side of warm economizer system in excision.
Middle temperature economizer system breaks down, by the barrier valve 812,813 of inlet flue gas baffle plate 7, exiting flue gas baffle plate, ' cigarette-water ' heat-exchanger rig 81 and the barrier valve 822,823 of ' cigarette-water ' heat-exchanger rig 82, isolated and water side isolated of the fume side of warm economizer system in realization, thus in excision, warm economizer system recovers original system safe operation.
In the present embodiment, heat-exchanger rig 9 is ' wind-vapour ' heat-exchanger rig, and the wind side of ' wind-vapour ' heat-exchanger rig is connected to air preheater 3 air intake, and the vapour side of ' wind-vapour ' heat-exchanger rig is connected to steam.Thermal source is steam, can heat cold First air, also can heat cold Secondary Air, can also heat cold First air and cold Secondary Air simultaneously.Steam is the auxiliary vapour of unit, low-pressure pumping steam or other are higher than the water vapour of 100 DEG C.
In the present embodiment, heat-exchanger rig 9 also can be ' wind-water ' heat-exchanger rig, and the wind side of ' wind-water ' heat-exchanger rig connects air preheater 3 air intake, and the water side of ' wind-water ' heat-exchanger rig connects hot water.Thermal source is hot water, can heat cold First air, also can heat cold Secondary Air, can also heat cold First air and cold Secondary Air simultaneously.Hot water is backwater in unit heat supply network, the backwater of low-level (stack-gas) economizer or other are higher than the hot water of 50 DEG C, but the thermal source quality need guaranteeing to heat air intake is starkly lower than the energy figure of recovery, to guarantee the raising of economy.
Adopt the middle temperature economizer system in the present embodiment, the method for Mist heat recovering is as follows:
(1) at the flue splitter section flue gas of air preheater 3 import department, the flue gas distributed enters middle temperature economizer system, and heat-exchanger rig 9 heats air preheater 3 air intake;
(2) flue gas distributed flows through the water of ' cigarette-water ' heat-exchanger rig 81,82 of middle temperature economizer system, and water absorbs heat and returns therrmodynamic system again, with Mist heat recovering;
(3) in air preheater 3 exit, the flue gas that the flue gas distributed and air preheater 3 export collects.
The flue gas of air preheater 3 import department shunting enters middle temperature economizer system, is progressively cooled; Because part of smoke enters middle temperature economizer system, the exhaust gas volumn entering air preheater 3 can decline, and air preheater 3 intake does not change, although air preheater 3 EAT can have suitable lifting because of the heat-exchanger rig of heating boiler air intake, but still the flue-gas temperature that can control air preheater 3 outlet declines.The flue-gas temperature that the flue gas of middle temperature economizer system outlet and air preheater 3 export all is reduced, and then collects and enters deduster 4, thus improve efficiency of dust collection.
If do not use heat-exchanger rig 9 to heat air preheater 3 air intake, only use ' cigarette-water ' heat-exchanger rig 81,82, air preheater 3 exports cigarette temperature can corresponding reduction, causes the risk of air preheater 3 cold junction cold end corrosion and blocking sharply to increase.Heat-exchanger rig 9 is used to heat air preheater 3 air intake, the wind-warm syndrome entering air preheater 3 rises, as long as guarantee that the mean temperature of air preheater 3 cold junction wind side now and cigarette side is equal to or higher than former design load, just can guarantee that the heat exchanger fin surface of its cold junction does not occur condensation, corrosion and blocks when exhaust gas temperature declines.
Adopt the method for the Mist heat recovering in the present embodiment, under the condition ensureing air preheater safe operation, can waste heat in recovery boiler tail flue gas, reach energy-conservation object, cigarette temperature can be reduced again, meet the requirement of low cold precipitator import cigarette temperature, improve efficiency of dust collection.Thus reach the object taking into account safe, energy-conservation and environmental protection.
The course of work of the middle temperature economizer system in the present embodiment is as follows:
Cigarette effluent journey: the part of smoke that air preheater 3 import department distributes enters ' cigarette-water ' heat-exchanger rig 81,82 successively, is cooled by progressively classification; On the other hand, the exhaust gas volumn entering air preheater 3 can decline, and air preheater 3 intake does not become, air preheater 3 EAT has suitable lifting because of ' wind-vapour ' or ' wind-water ' heat-exchanger rig, according to thermal conduction study general principle, the flue-gas temperature decline that air preheater 3 exports still can be controlled; The flue gas that the flue gas of middle temperature economizer system outlet and air preheater 3 export collects, and enters deduster 4.
Water effluent journey: flow through the high-pressure feed water of ' cigarette-water ' heat-exchanger rig 81, flow through the condensate water of ' cigarette-water ' heat-exchanger rig 82 and heated successively.
Unit in the present embodiment is 600MW Subcritical Units, and before unit is unkitted middle temperature economizer system, main relevant parameters is as shown in the table:
| Title | Unit | Numerical value |
| Air preheater input gas temperature | ℃ | 369 |
| Air preheater exit gas temperature | ℃ | 130 |
| Air preheater import amount of flue gas emission | T/h | 2700 |
| Air preheater import wind-warm syndrome | ℃ | 20 |
| High-pressure feed water flow | T/h | 1800 |
| Condensing water flow | T/h | 1360 |
| Smoke discharge amount | mg/m 3 | 29 |
In unit installing, after warm economizer system, main relevant parameters is as shown in the table:
| Title | Unit | Numerical value |
| Air preheater input gas temperature | ℃ | 369 |
| Air preheater exit gas temperature | ℃ | 110 |
| Air preheater import amount of flue gas emission | T/h | 2290 |
| Air preheater import wind-warm syndrome | ℃ | 70 |
| Middle temperature high-pressure economizer feedwater flow | T/h | 200 |
| Middle temperature low-pressure coal saver condensing water flow | T/h | 300 |
| The comprehensive overall presure drop of fume side | Pa | 750 |
| High-pressure feed water side pressure is fallen | Bar | 0.6 |
| Condensate water pressure drop | Bar | 0.8 |
| Smoke discharge amount | mg/m 3 | 22 |
As calculated, the middle temperature economizer system in the present embodiment comes into operation, and can reduce unit coal consumption and be about 2.5g/KWh.Smoke discharge amount declines 24% simultaneously.
In another embodiment of the present invention, middle temperature economizer system comprises ' cigarette-water ' heat-exchanger rig, the mouth that enters of ' cigarette-water ' heat-exchanger rig is connected by the first flue with the flue of air preheater import department, and the outlet flue of ' cigarette-water ' heat-exchanger rig is connected by the second flue with the flue in air preheater exit.
The method of middle temperature economizer system provided by the invention and Mist heat recovering thereof, splitter section flue gas is adopted to be used for middle temperature economizer system, middle temperature economizer system flue is formed in parallel with air preheater cigarette side, under the condition ensureing unit safety operation, can waste heat in recovery boiler tail flue gas, reach energy-conservation object, cigarette temperature can be reduced again, meet low cold precipitator high-effective dust-removing to the requirement of import cigarette temperature; The cigarette side inlet porting gas baffle of middle temperature economizer system, water side arranges barrier valve, if middle temperature economizer system breaks down, can by closing inlet flue gas baffle plate, the cigarette side of warm economizer system in cut-out; By closing barrier valve, the water side of warm economizer system in cut-out; Thus warm economizer system recovers former machine set system state continuation safe operation in cutting off; Middle temperature economizer system is at cigarette side inlet porting gas baffle, in water side, control valve is set, operating mode that can be different according to unit, the exhaust gas volumn of middle temperature economizer system is entered by inlet flue gas baffle controls, the water yield of middle temperature economizer system is entered by governor valve control, thus according to the effective Mist heat recovering of unit different load operating mode, improve unit operation economy; Utilize steam or hot water to heat air preheater air intake by ' wind-vapour/water ' heat-exchanger rig simultaneously, avoid because of in the air preheater outlet cigarette temperature drop that causes of warm economizer system splitter section flue gas low, and then avoid the problems such as air preheater cold-end air cold end corrosion and blocking, ensure unit safety operation.
More than describe preferred embodiment of the present invention in detail.Should be appreciated that those of ordinary skill in the art just design according to the present invention can make many modifications and variations without the need to creative work.Therefore, all technical staff in the art, all should by the determined protection domain of claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.
Claims (29)
1. warm economizer system in a kind, comprise at least one ' cigarette-water ' heat-exchanger rig, the first flue and second flue, it is characterized in that, the mouth that enters of described ' cigarette-water ' heat-exchanger rig is connected by described first flue with the flue of air preheater import department, the outlet flue of described ' cigarette-water ' heat-exchanger rig is connected by described second flue with the flue in described air preheater exit, and described middle temperature economizer system also comprises the heat-exchanger rig heating described air preheater air intake.
2. warm economizer system in as claimed in claim 1, is characterized in that, inlet porting gas baffle in described first flue.
3. warm economizer system in as claimed in claim 1, is characterized in that, arrange outlet gas baffle in described second flue.
4. warm economizer system in as claimed in claim 1, it is characterized in that, the water side water inlet of described ' cigarette-water ' heat-exchanger rig arranges barrier valve.
5. warm economizer system in as claimed in claim 1, it is characterized in that, the water side delivery port of described ' cigarette-water ' heat-exchanger rig arranges barrier valve.
6. warm economizer system in as claimed in claim 1, it is characterized in that, the water side water inlet of described ' cigarette-water ' heat-exchanger rig arranges control valve, for regulating the water yield entering described ' cigarette-water ' heat-exchanger rig.
7. warm economizer system in as claimed in claim 1, it is characterized in that, described ' cigarette-water ' heat-exchanger rig is one.
8. warm economizer system in as claimed in claim 1, it is characterized in that, described ' cigarette-water ' heat-exchanger rig is multiple.
9. warm economizer system in as claimed in claim 8, it is characterized in that, the flue of multiple described ' cigarette-water ' heat-exchanger rig connects successively, the mouth that enters of ' cigarette-water ' heat-exchanger rig described in first is connected by described first flue with the flue of described air preheater import department, and described in last, the outlet flue of ' cigarette-water ' heat-exchanger rig is connected by described second flue with the flue in described air preheater exit.
10. warm economizer system in as claimed in claim 1, it is characterized in that, described heat-exchanger rig is ' wind-vapour ' heat-exchanger rig, and the air side of described ' wind-vapour ' heat-exchanger rig connects described air preheater air intake, and the vapour side of described ' wind-vapour ' heat-exchanger rig connects steam.
11. as claimed in claim 10 in warm economizer system, it is characterized in that, described steam is extracted steam from turbine or auxiliary vapour.
12. as claimed in claim 10 in warm economizer system, it is characterized in that, described steam is the water vapour higher than 100 DEG C.
13. as claimed in claim 1 in warm economizer system, it is characterized in that, described heat-exchanger rig is ' wind-water ' heat-exchanger rig, and the air side of described ' wind-water ' heat-exchanger rig connects described air preheater air intake, and the water side of described ' wind-water ' heat-exchanger rig connects hot water.
14. as claimed in claim 13 in warm economizer system, it is characterized in that, described hot water is heat supply network backwater or low-level (stack-gas) economizer backwater.
15. as claimed in claim 13 in warm economizer system, it is characterized in that, described hot water is the hot water higher than 50 DEG C.
16. as claimed in claim 1 in warm economizer system, it is characterized in that, the wind side of described heat-exchanger rig connects described air preheater air intake, the thermal source quality that described heat-exchanger rig uses lower than the quality recovered energy, to guarantee the raising of economy.
17. 1 kinds of methods adopting the middle temperature economizer system Mist heat recovering described in any one of claim 1-16, is characterized in that, comprise the following steps:
(1) at the flue splitter section flue gas of described air preheater import department, the flue gas distributed enters described middle temperature economizer system, and described heat-exchanger rig heats described air preheater air intake;
(2) flue gas distributed described in flows through the water of ' cigarette-water ' heat-exchanger rig of described middle temperature economizer system, and described water absorbs heat and returns therrmodynamic system again, with Mist heat recovering;
(3) in described air preheater exit, described in the flue gas that exports of the flue gas that distributes and described air preheater collect.
The method of 18. Mist heat recoverings as claimed in claim 17, is characterized in that, the method for described Mist heat recovering also comprises adjustment inlet flue gas baffle plate, to control the exhaust gas volumn distributed.
The method of 19. Mist heat recoverings as claimed in claim 17, is characterized in that, when described middle temperature economizer system breaks down, closes inlet flue gas baffle plate, to cut off the flue gas stream of described middle temperature economizer system.
The method of 20. Mist heat recoverings as claimed in claim 17, it is characterized in that, the method of described Mist heat recovering also comprises the control valve that adjustment is arranged at described ' cigarette-water ' heat-exchanger rig water side, with the water yield of control flow check through described ' cigarette-water ' heat-exchanger rig.
The method of 21. Mist heat recoverings as claimed in claim 17, it is characterized in that, when described middle temperature economizer system breaks down, closedown is arranged at described ' cigarette-water ' heat-exchanger rig water side-entrance barrier valve, or close and be arranged at described ' cigarette-water ' heat-exchanger rig water side outlet barrier valve, or close the import barrier valve and outlet barrier valve that are arranged at described ' cigarette-water ' heat-exchanger rig water side, with the water side of isolated described ' cigarette-water ' heat-exchanger rig simultaneously.
The method of 22. Mist heat recoverings as claimed in claim 17, it is characterized in that, described heating air preheater air intake comprises the cold First air of heating air preheater, the heating cold Secondary Air of air preheater or heats the cold First air of air preheater and cold Secondary Air simultaneously.
The method of 23. Mist heat recoverings as claimed in claim 17, is characterized in that, described heat-exchanger rig adopts ' wind-vapour ' heat-exchanger rig.
The method of 24. Mist heat recoverings as claimed in claim 23, is characterized in that, the thermal source of described ' wind-vapour ' heat-exchanger rig is the auxiliary vapour of unit or extracted steam from turbine.
The method of 25. Mist heat recoverings as claimed in claim 23, is characterized in that, the thermal source of described ' wind-vapour ' heat-exchanger rig is the water vapour higher than 100 DEG C.
The method of 26. Mist heat recoverings as claimed in claim 17, is characterized in that, described heat-exchanger rig adopts ' wind-water ' heat-exchanger rig.
The method of 27. Mist heat recoverings as claimed in claim 26, is characterized in that, the thermal source of described ' wind-water ' heat-exchanger rig is heat supply network backwater or low-level (stack-gas) economizer backwater.
The method of 28. Mist heat recoverings as claimed in claim 26, is characterized in that, the thermal source of described ' wind-water ' heat-exchanger rig is the hot water higher than 50 DEG C.
The method of 29. Mist heat recoverings as claimed in claim 17, is characterized in that, described heat-exchanger rig uses the quality of thermal source lower than the quality recovered energy, to guarantee the raising of economy.
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| CN107792905A (en) * | 2016-08-30 | 2018-03-13 | 舒少辛 | A kind of desulfurizing waste water processing device and its processing method |
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