CN104807035B

CN104807035B - A kind of air preheat and smoke waste heat utilization system and method

Info

Publication number: CN104807035B
Application number: CN201510236632.2A
Authority: CN
Inventors: 郝江平; 姜平; 魏绍清
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-04-22
Filing date: 2015-05-11
Publication date: 2017-10-03
Anticipated expiration: 2035-05-11
Also published as: CN204693472U; CN104807035A

Abstract

Present invention is particularly directed to the air preheat technical field of boiler.The air preheat of the present invention and smoke waste heat utilization system, including：Exhaust gases passes (17), air duct (20), air preheater (9), condensate chimney heat exchanger (8) and condensate air duct heat exchanger (19), in addition to：Condensate comes supply mains (15), coagulation hydroenergy backwater house steward (12)；The exhaust gases passes (17) and air duct (20) are connected with air preheater (9)；The condensate chimney heat exchanger (8) is arranged on the exhaust gases passes (17) after air preheater (9) along flue gas flow direction；The condensate air duct heat exchanger (19) is arranged on the air duct (20) before air preheater (9) along air flow.The present invention can automatically adjust smoke evacuation heat exchange according to the change of service condition, realize on the premise of ensuring that heating surface safety and system are normally run, ensure the maximization of efficiency of thermal cycle and system economy.

Description

A kind of air preheat and smoke waste heat utilization system and method

Technical field

The field such as utilize the invention belongs to the recuperation of heat of boiler smoke and production technology tail gas, particular for the air of boiler Preheating technology field, in particular it relates to a kind of air preheat and smoke waste heat utilization system and method.

Background technology

All the time there is equipment investment, heating surface safety, system normally operation and the coupling of the thermal efficiency in conventional air preheater Problem.Increase the investment of heat-transfer surface, more flue gas heats are passed into air can improve system thermal efficiency, but reduce smoke evacuation Temperature is more easy to make heat-transfer surface occur low-temperature corrosion, while causing serious stifled ash, heat transfer efficiency is reduced again., whereas if improving Exhaust gas temperature, although low-temperature corrosion can be mitigated and the harm of ash is blocked up, but system thermal efficiency is reduced.

In the case where not changing boiler and therrmodynamic system global design, great limitation can be had by carrying out traditional air preheater design. On the other hand, the need for the design of empty pre- outlet air temperature need to meet combustion system, for using low-volatile coal and poor quality The boiler combustion system of coal generally requires higher hot air temperature.At this moment the exhaust gas temperature designed often higher than flue gas acid dew point A lot, very big heat loss is caused.

Simple transformation air preheater, increases heat-transfer surface, can not ensure Best Economy.The equal root of conventional air preheater According to design conditions using fixed design parameter, the exchange capability of heat of heat transmission equipment is unadjustable.Thus, the design or reality is made Exhaust gas temperature is too high, causes heat loss very big, or makes the too low low temperature for causing air preheater of actual exhaust gas temperature rotten Erosion and stifled ash.In addition, existing heat recovery technology is when designing the system of recovery waste heat, because waste-heat recovery device adjusts energy The limitation of power, the place capacity that the heat either reclaimed not necessarily can be optimised or reclaimed heat is not enough.

The design of steam air heater mainly meets the empty pre- intake air needs of winter heating, and has preferable backheat economy Property.Existing steam air heater can be as a kind of regulating measure of flue gas exhaust gas temperature, but its throwing stops control and regulating power and can not fitted Environment temperature and the frequent of flue-gas temperature significantly change when answering Different climate and unit load change.

Improved with the requirement of energy-saving and emission-reduction, current boiler generally uses SCR flue gas denitrification systems, and after air preheater Exhaust gas temperature design load becomes lower.But the SCR denitration system that boiler is used can be improved after flue gas acid dew point, and denitration in flue gas Hydrogen sulfate ammonia (NH₄)HSO₄, the stifled ash of caking property of air preheater cold-end air can be aggravated.Improve the import wind-warm syndrome of air preheater Be conducive to mitigating the low-temperature corrosion of air preheater and stifled ash, but raising wind-warm syndrome can also increase the smoke evacuation temperature after air preheater Degree, increases flue gas loss.

Current air preheater rear pass generally carries out the recovery of fume afterheat, but the technology using low-level (stack-gas) economizer technology Air preheater entrance wind-warm syndrome can not be solved to improve with reducing the contradiction of cigarette temperature after air preheater.

Further, since there is design deviation, and avoid the low-temperature corrosion of air preheater and stifled ash, current boiler exhaust gas The design of temperature is generally guarded, and many systems set up low-level (stack-gas) economizer to correct design deviation by rear portion, reduce flue gas loss. But the scheme of low-level (stack-gas) economizer is practically without realizing the cascade utilization of energy, the low-quality heat energy that may return to boiler is used for Exclusion steam turbine draws gas, and does the Rankine cycle of low parameter, reduces the thermal efficiency of cycle and economy of system.

The content of the invention

The problem of existing for prior art, the present invention develops a kind of new air preheat and fume afterheat using system System, can automatically adjust smoke evacuation heat exchange according to the change of service condition, and realization is ensuring what heating surface safety and system were normally run Under the premise of, ensure the maximization of efficiency of thermal cycle and system economy.

The air preheat of the present invention and smoke waste heat utilization system, including：Exhaust gases passes 17, air duct 20, air are pre- Hot device 9, condensate chimney heat exchanger 8 and condensate air duct heat exchanger 19, wherein, in addition to：Condensate come supply mains 15, Coagulation hydroenergy backwater house steward 12；

The exhaust gases passes 17 and air duct 20 are connected with air preheater 9；

The condensate chimney heat exchanger 8 is arranged on the exhaust gases passes 17 after air preheater 9 along flue gas flow direction；It is described Condensate air duct heat exchanger 19 is arranged on the air duct 20 before air preheater 9 along air flow；

The entrance of the condensate of the condensate air duct heat exchanger 19 carrys out supply mains 15 with condensate and is connected；It is described solidifying The outlet for bearing water chimney heat exchanger 8 is connected with coagulation hydroenergy backwater house steward 12；The condensation of the condensate air duct heat exchanger 19 The outlet of water and the entrance of condensate chimney heat exchanger 8 are connected with condensing the two ends of shredded tobacco for water pipes air channel heat exchanger connecting tube 6 respectively；

The condensate comes between supply mains 15 and condensation shredded tobacco for water pipes air channel heat exchanger connecting tube 6, is exchanged heat by air duct Device condensate shunt valve is connected, and air duct heat exchanger condensate is provided with the air duct heat exchanger condensate shunt valve Bypass valve 10.

According to the air preheat of the present invention and smoke waste heat utilization system, preferably, on the exhaust gases passes (17) Chimney heat exchanger exit gas temperature sensor (16) is provided with the export pipeline of condensate chimney heat exchanger (8)；It is described Condensate comes on supply mains (15) with being provided with condensate air after air duct heat exchanger condensate shunt valve tie point Channel heat exchanger inlet regulating valve (18).

According to the air preheat of the present invention and smoke waste heat utilization system, preferably, in the condensation shredded tobacco for water pipes air channel In heat exchanger connecting tube 6, set between the tie point and condensate chimney heat exchanger 8 of air duct heat exchanger condensate shunt valve It is equipped with condensate chimney heat exchanger inlet water temperature sensor 7；The coagulation hydroenergy backwater house steward 12 is with condensing shredded tobacco for water pipes air channel heat exchanger Connected between connecting tube 6 by chimney heat exchanger condensate recirculating water pipe；The one of the chimney heat exchanger condensate recirculating water pipe End is connected to any position condensed in shredded tobacco for water pipes air channel heat exchanger connecting tube 6 before condensate chimney heat exchanger inlet water temperature sensor 7 Put；On chimney heat exchanger condensate recirculating water pipe chimney heat exchanger condensate recirculation pump 13 is disposed with along condensation current direction Regulating valve 11 is recycled with chimney heat exchanger condensate.

According to the present invention air preheat and smoke waste heat utilization system, preferably, on the air duct 20 Air preheater inlet air temperature sensor 5 is provided between air preheater 9 and condensate air duct heat exchanger 19；Institute State condensate come supply mains 15 and chimney heat exchanger condensate recirculating water pipe pass through cigarette air channel heat exchanger condensate recirculating water pipe connect Connect；One end of the cigarette air channel heat exchanger condensate recirculating water pipe is connected to chimney heat exchanger condensate recirculating water pipe upper flue and changed Between hot device condensate recirculation pump 13 and chimney heat exchanger condensate recycling regulating valve 11, the other end is connected to condensate The upper air passage heat exchanger condensate shunt valve of supply mains 15 comes before the tie point of supply mains 15 with condensate；The cigarette air channel is changed Cigarette air channel heat exchanger condensate recycling regulating valve 14 is provided with hot device condensate recirculating water pipe.

According to the air preheat of the present invention and smoke waste heat utilization system, preferably, the overhead of air duct 20 The heating of one-level steam air is provided between air preheater inlet air temperature sensor 5 and condensate air duct heat exchanger 19 Device 3 and second steam air heater 4；The steam side difference of one-level steam air heater 3 and second steam air heater 4 It is connected with respective external vapour source steam inlet pipe, the external vapour source steam inlet pipe of one-level steam air heater 3 is provided with main air Heat into steam control valve 1；The external vapour source steam inlet pipe of second steam air heater 4 is provided with secondary air and heated into vapour regulation Valve 2.

According to the air preheat of the present invention and smoke waste heat utilization system, preferably, the air duct 20 and solidifying Bear water and be provided with one-level steam air heater 3 and second steam air heater 4 between air duct heat exchanger 19；One-level is steamed The steam side of vapour air heater 3 and second steam air heater 4 is connected with respective external vapour source steam inlet pipe respectively, one-level The external vapour source steam inlet pipe of steam air heater 3 is provided with main air and heated into steam control valve 1；Second steam air is heated The external vapour source steam inlet pipe of device 4 is provided with secondary air and heated into steam control valve 2.

According to the present invention air preheat and smoke waste heat utilization system, preferably, on the exhaust gases passes 17 Low temperature flue heat exchanger is provided with after condensate chimney heat exchanger 8；The low temperature flue heat exchanger is arranged on air duct heat exchanger Condensate shunt valve and cigarette air channel heat exchanger condensate recirculating water pipe and condensate come between the link position of supply mains 15, or The low temperature flue heat exchanger is arranged on condensate air duct heat exchanger inlet regulating valve 18 and air duct heat exchanger condenses Water shunt valve and condensate come between the link position of supply mains 15.

Air preheat based on above-mentioned air preheat and smoke waste heat utilization system and fume afterheat profit that the present invention is provided With method, comprise the following steps：

The condensate for flowing through air duct heat exchanger 19 comes the condensate in supply mains 15 and the air in air duct 20 Heat exchange, condensate transfers heat to air, condensing water temperature reduction, air themperature rise；

High-temperature flue gas in the exhaust gases passes 17 flows through air preheater 9, empty with flowing through condensate in air duct 20 Gas channel heat exchanger 19 enters the air heat-exchange of air preheater 9 after being heated, reduce flue-gas temperature, and air themperature is improved；

Heat smoke after the air preheater 9 in exhaust gases passes 17 flows through condensate chimney heat exchanger 8, by heat transfer To the condensate for flowing through condensate chimney heat exchanger 8, reduce flue-gas temperature, condensing water temperature is improved；Absorb fume afterheat The higher condensate of temperature return to therrmodynamic system through coagulation hydroenergy backwater house steward 12, fume afterheat is utilized.

The air duct heat exchanger condensate bypass valve 10 is according to chimney heat exchanger exit gas temperature sensor 16 measured values control aperture；Flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor 16 is changed higher than flue Hot device exit gas temperature setting the 1st is worth, the aperture of air duct heat exchanger condensate bypass valve 10 increase, to reduce or disappear Except the deviation between the value of chimney heat exchanger exit gas temperature and chimney heat exchanger exit gas temperature setting the 1st of measurement；Or Person, the flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor 16 is less than chimney heat exchanger exiting flue gas temperature Degree setting the 1st is worth, and the aperture of air duct heat exchanger condensate bypass valve 10 reduces；

Condensate air duct heat exchanger inlet regulating valve 18 coordinates air duct heat exchanger condensate bypass valve 10 Regulation；Flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor 16 is higher than chimney heat exchanger exiting flue gas Temperature setting the 1st is worth, and the aperture of condensate air duct heat exchanger inlet regulating valve 18 reduces, so that the flue of measurement is reduced or eliminated Deviation between heat exchanger exit flue-gas temperature and the value of chimney heat exchanger exit gas temperature setting the 1st；Or, the flue is changed Flue-gas temperature measured by hot device exit gas temperature sensor 16 is worth less than chimney heat exchanger exit gas temperature setting the 1st, The aperture of condensate air duct heat exchanger inlet regulating valve 18 increases.

According to the air preheat of the present invention and fume afterheat Application way, preferably, the air duct heat exchanger Condensate bypass valve 10 and condensate air duct heat exchanger inlet regulating valve 18 are according to condensate chimney heat exchanger entrance The measured value control aperture of cooling-water temperature sensor 7, the entrance of control condensate chimney heat exchanger 8 condenses water temperature, prevents from condensing shredded tobacco for water pipes Serious low-temperature corrosion and stifled ash occur for road heat exchanger 8；Wherein, for equipment safety, condensate bypass valve (10) is by water Condensing water temperature control measured by temperature sensor (7) according to chimney heat exchanger exit gas temperature sensor (16) prior to surveying Value controls aperture；

Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor 7 is changed less than condensate flue Hot device inlet water temperature setting value 1, the aperture of air duct heat exchanger condensate bypass valve 10 increase, so that measurement is reduced or eliminated Condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1 between deviation；Or, institute State the condensing water temperature measured by condensate chimney heat exchanger inlet water temperature sensor 7 and enter saliva higher than condensate chimney heat exchanger Warm setting value 1, the aperture of air duct heat exchanger condensate bypass valve 10 reduces；

The condensate air duct heat exchanger inlet regulating valve 18 coordinates the bypass regulation of air duct heat exchanger condensate Valve 10 is adjusted；Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor 7 is less than condensate flue Heat exchanger entrance water temperature setting value 1, the aperture of condensate air duct heat exchanger inlet regulating valve 18 reduces, so that survey is reduced or eliminated Deviation between the condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1 of amount；Or, Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor 7 is higher than condensate chimney heat exchanger entrance Water temperature setting value 1, the increase of the aperture of condensate air duct heat exchanger inlet regulating valve 18.

According to the air preheat of the present invention and fume afterheat Application way, preferably, condensed by chimney heat exchanger The entrance that water is recycled for adjusting condensate chimney heat exchanger 8 condenses water temperature；

Chimney heat exchanger condensate recycles survey of the regulating valve 11 according to condensate chimney heat exchanger inlet water temperature sensor 7 Value controls aperture；Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor 7 is less than condensate Chimney heat exchanger inlet water temperature setting value 2, chimney heat exchanger condensate recycling regulating valve 11 aperture increase, to be reduced or eliminated Deviation between the condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 2 of measurement；Or Person, the condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor 7 is higher than condensate chimney heat exchanger Inlet water temperature setting value 2, chimney heat exchanger condensate recycling regulating valve 11 aperture reduces.

According to the air preheat of the present invention and fume afterheat Application way, preferably, chimney heat exchanger condensate is again Circulating pump 13 is automatic according to the difference setting value progress for pumping out water pressure higher than condensate to condense water pressure in supply mains 15 Or manual variable frequency adjustment, the actual measurement difference be less than the difference setting value, water pump operation frequency improve, the difference of the pressure with Difference setting value deviation is reduced or eliminated；Or, the actual measurement difference is higher than the difference setting value, and water pump operation frequency is reduced, The difference and difference setting value deviation of the pressure are reduced or eliminated.

It is preferably, solidifying using cigarette air channel heat exchanger according to the air preheat of the present invention and fume afterheat Application way Bear water and be recycled for the condensate inlet water temperature that control enters condensate air duct heat exchanger 19, so as to control air preheater 9 entering air temperature or the condensate inlet water temperature of condensate chimney heat exchanger (8)；

Cigarette air channel heat exchanger condensate recycles survey of the regulating valve 14 according to air preheater inlet air temperature sensor 5 Value controls aperture；Air themperature measured by the air preheater inlet air temperature sensor 5 is less than air preheater Entering air temperature setting the 1st is worth, cigarette air channel heat exchanger condensate recycling regulating valve 14 aperture increase, so that survey is reduced or eliminated Deviation between the value of air preheater entering air temperature and air preheater entering air temperature setting the 1st of amount；The latter, institute The air themperature measured by air preheater inlet air temperature sensor 5 is stated to set higher than air preheater entering air temperature 1st value, cigarette air channel heat exchanger condensate recycling regulating valve 14 aperture reduces；

Or, cigarette air channel heat exchanger condensate recycles regulating valve 14 and sensed according to condensate chimney heat exchanger inlet water temperature The condensate inlet water temperature control aperture for the condensate chimney heat exchanger that device 7 is measured；The condensation of the condensate chimney heat exchanger Water inlet water temperature is less than setting value, cigarette air channel heat exchanger condensate recycling regulating valve 14 aperture increase, to be reduced or eliminated partially Difference；Or, the condensate inlet water temperature of the condensate chimney heat exchanger is higher than setting value, and cigarette air channel heat exchanger condensate is followed again The aperture of ring regulating valve 14 reduces.

According to the air preheat of the present invention and fume afterheat Application way, preferably, air duct heat exchanger is flowed through Air after 19 enters back into air preheat after first passing through one-level steam air heater 3 and the heating of second steam air heater 4 Device 9；Heating steam is surveyed in one-level steam air heater 3 and the vapour of second steam air heater 4 and transfers heat to air side Air after be condensed into water and return to corresponding recovery system and utilize；

The main air heats the measured value according to chimney heat exchanger exit gas temperature sensor 16 into steam control valve 1 Combination with the measured value of air preheater inlet air temperature sensor 5 controls aperture；The air preheater intake air Air themperature measured by temperature sensor 5 is worth less than air preheater entering air temperature setting the 2nd, main air heat into The aperture of steam control valve 1 increases, empty with air preheater entering air temperature and air preheater entrance that measurement is reduced or eliminated Deviation between the value of temperature degree setting the 2nd；The measured value of the chimney heat exchanger exit gas temperature sensor 16 is higher than flue Heat exchanger exit flue-gas temperature setting the 2nd is worth, and air is heated to be reduced into the aperture of steam control valve 1, so that the cigarette of measurement is reduced or eliminated Deviation between road heat exchanger exit flue-gas temperature and the value of chimney heat exchanger exit gas temperature setting the 2nd；Or, the air Air themperature measured by pre-heater inlet air temperature sensor 5 is worth higher than air preheater entering air temperature setting the 2nd, Main air is heated to be reduced into the aperture of steam control valve 1；The measured value of the chimney heat exchanger exit gas temperature sensor 16 is low It is worth in chimney heat exchanger exit gas temperature setting the 2nd, air is heated into the increase of the aperture of steam control valve 1；

The secondary air heats the measured value according to chimney heat exchanger exit gas temperature sensor 16 into steam control valve 2 Combination with the measured value of air preheater inlet air temperature sensor 5 controls aperture；The air preheater intake air Air themperature measured by temperature sensor 5 is worth less than air preheater entering air temperature setting the 3rd, secondary air heat into The aperture of steam control valve 2 increases, empty with air preheater entering air temperature and air preheater entrance that measurement is reduced or eliminated Deviation between the value of temperature degree setting the 3rd；The measured value of the chimney heat exchanger exit gas temperature sensor 16 is higher than flue Heat exchanger exit flue-gas temperature setting the 3rd is worth, and secondary air is heated to be reduced into the aperture of steam control valve 2, so that measurement is reduced or eliminated Chimney heat exchanger exit gas temperature and chimney heat exchanger exit gas temperature setting the 3rd value between deviation；

Or, the air themperature measured by the air preheater inlet air temperature sensor 5 is higher than air preheater Entering air temperature setting the 3rd is worth, and secondary air is heated to be reduced into the aperture of steam control valve 2；The chimney heat exchanger exiting flue gas The measured value of temperature sensor 16 is worth less than chimney heat exchanger exit gas temperature setting the 3rd, and secondary air is heated into vapour regulation The aperture of valve 2 increases.

According to the air preheat of the present invention and fume afterheat Application way, the chimney heat exchanger exit gas temperature setting 1st value is less than chimney heat exchanger exit gas temperature and sets 1~20 DEG C of the 2nd value, and the chimney heat exchanger exit gas temperature is set Fixed 2nd value is less than chimney heat exchanger exit gas temperature and sets 1~20 DEG C of the 3rd value.The chimney heat exchanger exit gas temperature The 1st value, the 2nd value, the 3rd value preferred scope are set as 50~160 DEG C, coal and heat-transfer surface design etc. can be used according to boiler specific Situation is set.

The value of air preheater entering air temperature setting the 1st is more than air preheater entering air temperature setting the 2nd 1~30 DEG C of value；The value of air preheater entering air temperature setting the 2nd is more than air preheater entering air temperature setting the 3 1~30 DEG C of values.The air themperature sets the 1st value, the 2nd value, the 3rd value preferred scope as -30~100 DEG C, can be fired according to boiler Set with concrete conditions such as coal and air preheater designs, when being unfavorable for the equipment safety of air preheater 9, each setting value Temperature is accordingly improved.

According to the air preheat of the present invention and fume afterheat Application way, when air preheater entering air temperature is too low When, it will allow to properly increase chimney heat exchanger exit gas temperature, ensure that the equipment of air preheater 9 is pacified in the way of sacrificing efficiency Entirely, air preheater entering air temperature is lower, it is allowed to chimney heat exchanger exit gas temperature it is higher.

The condensate chimney heat exchanger inlet water temperature setting value 1, the preferred scope of setting value 2 are less than flue gas acid dew point 80 DEG C and higher than between 10 DEG C of scopes of flue gas acid dew point.

Each value described above can be set according to the common knowledge of the specific combustion case of upstream boiler and this area It is fixed.

Advantages of the present invention is specific as follows：

1st, the present invention solves the drawbacks of conventional air preheater (particularly heat accumulating type) is present, and can be achieved to release tradition sky Coupled problem present in gas preheating technology.The low-temperature zone of air preheat uses wall-type heat exchange, in reduction heat loss due to exhaust gas The entrance wind-warm syndrome of conventional air preheater is added simultaneously.It can be realized by automatically controlling in control conventional air preheater low temperature Corrosion and the benefit for blocking up raising flue gas heat recovery under grey preceding topic.Reliable control low-temperature corrosion of air preheater and stifled ash Farthest Mist heat recovering can be achieved, while making fume afterheat preferentially heat air, then unnecessary heat adds again Heat setting is born water, and fume afterheat energy has obtained cascade utilization in the thermodynamic cycle entirely generated electricity, and farthest improves The benefit that fume afterheat is utilized.

2nd, the present invention first passes through condensate and heats wind, passes through water and recycling is controlled, you can reference temperature is higher to coagulate Bear water water and carry out efficient waste heat recycling, can also quote the relatively low condensate water heating air of temperature and realize efficient backheat. Air preheat can be played a part of and improve air preheater entering air temperature, while can suitably reduce chimney heat exchanger enters saliva Temperature, increases the heat transfer temperature difference and heat absorption capacity of chimney heat exchanger, is conducive to increasing the amplitude of flue gas cool-down and improves UTILIZATION OF VESIDUAL HEAT IN Smoke duster efficiency afterwards.While the higher condensate progress heat recovery of reference temperature can be squeezed, parameter is higher to take out Vapour, can improve the benefit of heat recovery.It is water-borne that temperature first passes through air channel less than the condensate water that chimney heat exchanger is exported After the relatively low air of air heater release heat temperature, the of a relatively high flue gas of temperature is absorbed by chimney heat exchanger again Waste heat, condenses water temperature and is improved so that the available loss of energy of diabatic process is minimum.

3rd, the present invention is flexibly using the combination of cigarette air channel heat exchanger condensate recycling, you can enhancing fume afterheat is used In the condensate loop control of heating boiler air feed, it reliably ensure that serious low temperature does not occur for the chimney heat exchanger of UTILIZATION OF VESIDUAL HEAT IN again Corrosion and stifled ash.The system time constant of chimney heat exchanger outlet condensate recycling control wall temperature is small, control accuracy and reliable Property it is high.

4th, can be when environment temperature be relatively low present invention employs the air channel auxiliary air heater of the external vapour source heating of two-stage The air themperature of air preheater entrance, and combustibility when improvement boiler start/ stop and underrun are further improved, Reduce incomplete combustion loss and the pollution to back-end surfaces and SCR flue gas denitrification systems.The vapour matchmaker air heating of one-level air channel Device and light breeze road vapour matchmaker air heater are temperature integrated by being discharged fume after air preheater entrance wind-warm syndrome and chimney heat exchanger respectively Control, the cigarette temperature setting value that one-level air channel vapour matchmaker air heater and light breeze road vapour matchmaker's air heater are controlled increases successively Greatly, air temperature set point is sequentially reduced, can be under conditions of air preheater safety is ensured as far as possible, and at utmost reduction is arranged Cigarette heat loss.

5th, air channel sets condensate air heat exchanger and external auxiliary steam air heater simultaneously, can be by chimney heat exchanger The regulation of exhaust gas temperature and the regulation that chimney heat exchanger entrance, outlet condense water temperature are mutually independent afterwards, it is advantageously ensured that waste heat recovery The safety of equipment and the unification and optimization of UTILIZATION OF VESIDUAL HEAT IN benefit.

Brief description of the drawings

The air preheat of Fig. 1 present invention and afterheat utilizing system schematic diagram.

Reference

1st, main air is heated heats into steam control valve into steam control valve 2, secondary air

3rd, one-level steam air heater 4, second steam air heater

5th, air preheater inlet air temperature sensor 6, condensation shredded tobacco for water pipes air channel heat exchanger connecting tube

7th, condensate chimney heat exchanger inlet water temperature sensor 8, condensate chimney heat exchanger

9th, air preheater 10, the bypass of air duct heat exchanger condensate are adjusted

11st, chimney heat exchanger condensate recycling regulating valve 12, coagulation hydroenergy backwater house steward

13rd, chimney heat exchanger condensate recirculation pump

14th, cigarette air channel heat exchanger condensate recycling regulating valve 15, condensate carry out supply mains

16th, chimney heat exchanger exit gas temperature sensor 17, exhaust gases passes

18th, condensate air duct heat exchanger inlet regulating valve 19, condensate air duct heat exchanger

20th, air duct

Embodiment

With reference to the accompanying drawings and detailed description, the present invention will be further described in detail.

A kind of new air preheat proposed by the present invention and afterheat utilizing system, as shown in Figure 1, system capital equipment Including：Exhaust gases passes 17, air duct 20, air preheater 9, condensate chimney heat exchanger 8 and the heat exchange of condensate air duct Device 19.

The exhaust gases passes 17 and air duct 20 are all connected with the air preheater 9；Flue gas in exhaust gases passes 17 Partial heat is passed to the air in air duct 20 by the air preheater 9.

The condensate chimney heat exchanger 8 is arranged in after air preheater 9 on the exhaust gases passes 17 of (along flue gas flow direction)；Institute Condensate air duct heat exchanger 19 is stated to be arranged in before air preheater 9 on the air duct 20 of (along air flow)；The cigarette Chimney heat exchanger exit gas temperature sensor 16 is provided with gas passage 17 after condensate chimney heat exchanger 8；

The entrance of the condensate of the condensate air duct heat exchanger 19 carrys out supply mains 15 with condensate and is connected；It is described solidifying The outlet for bearing water chimney heat exchanger 8 is connected with coagulation hydroenergy backwater house steward 12；The condensation of the condensate air duct heat exchanger 19 The outlet of water and the entrance of condensate chimney heat exchanger 8 are connected with condensing the two ends of shredded tobacco for water pipes air channel heat exchanger connecting tube 6 respectively；Institute State condensate and carry out on supply mains 15 to be provided with condensate air duct heat exchanger inlet regulating valve 18；The condensate carrys out supply mains 15 before condensate air duct heat exchanger inlet regulating valve 18, between condensation shredded tobacco for water pipes air channel heat exchanger connecting tube 6, passes through sky Gas channel heat exchanger condensate shunt valve is connected, and being provided with air duct on the air duct heat exchanger condensate shunt valve changes Hot device condensate bypass valve 10；

As an improvement, on shredded tobacco for water pipes air channel heat exchanger connecting tube 6 is condensed, with air duct heat exchanger condensate shunt valve Condensate chimney heat exchanger inlet water temperature sensor 7 is provided between tie point and condensate chimney heat exchanger 8；The condensate Connected between return main 12 and condensation shredded tobacco for water pipes air channel heat exchanger connecting tube 6 by chimney heat exchanger condensate recirculating water pipe；Institute The one end for stating chimney heat exchanger condensate recirculating water pipe is connected to condensate flue in condensation shredded tobacco for water pipes air channel heat exchanger connecting tube 6 and changed Optional position before hot device inlet water temperature sensor 7；Set successively along condensation current direction on chimney heat exchanger condensate recirculating water pipe It is equipped with chimney heat exchanger condensate recirculation pump 13 and chimney heat exchanger condensate recycling regulating valve 11；

As an improvement, being provided with air duct 20 between air preheater 9 and condensate air duct heat exchanger 19 Air preheater inlet air temperature sensor 5；The condensate comes supply mains 15 and chimney heat exchanger condensate recirculating water pipe Connected by cigarette air channel heat exchanger condensate recirculating water pipe；One end of the cigarette air channel heat exchanger condensate recirculating water pipe is connected to Chimney heat exchanger condensate recirculating water pipe upper flue heat exchanger condensate recirculation pump 13 and the recycling of chimney heat exchanger condensate Between regulating valve 11, the other end is connected to condensate and comes the upper air passage heat exchanger condensate shunt valve of supply mains 15 and condensate Before the tie point for carrying out supply mains 15；Cigarette air channel heat exchanger condensate is provided with the cigarette air channel heat exchanger condensate recirculating water pipe Recycle regulating valve 14；

As an improvement, air preheater inlet air temperature sensor 5 and condensate air duct are changed on air duct 20 One-level steam air heater 3 and second steam air heater 4 are provided between hot device 19；One-level steam air heater 3 It is connected respectively with respective external vapour source steam inlet pipe with the steam side of second steam air heater 4, the heating of one-level steam air The external vapour source steam inlet pipe of device 3 is provided with main air and heated into steam control valve 1；The external vapour of second steam air heater 4 Source steam inlet pipe is provided with secondary air and heated into steam control valve 2；Respective external vapour source can be same vapour source；

The one-level steam air heater 3 and second steam air heater 4 are on air duct 20 with air flow It can be connected in parallel, can also be connected in series；The one-level steam air heater 3 and second steam air heater 4 and Connection connection can be added by the way of both crisscross parallels with improving in one-level steam air heater 3 and second steam air The uniformity of air heating when hot device 4 only one puts into operation.

As an improvement, being provided with low temperature flue heat exchanger on exhaust gases passes 17 after condensate chimney heat exchanger 8, condensate comes The condensate of supply mains 15 first passes through the heating of low temperature flue heat exchanger before condensate air duct heat exchanger 19 is entered；Low temperature cigarette Road heat exchanger may be provided at air duct heat exchanger condensate shunt valve and cigarette air channel heat exchanger condensate recirculating water pipe with condensing Water comes between the link position of supply mains 15, may also be arranged on condensate air duct heat exchanger inlet regulating valve 18 and air is logical Road heat exchanger condensate shunt valve and condensate come between the link position of supply mains 15.

Condensate carrys out condensate water in supply mains 15 and is mainly derived from steam turbine side one-level low-pressure heater entrance condensate House steward, when condensate come coolant-temperature gage it is relatively low when, supply mains's extension condensate can be condensed by the outlet of this grade of low-pressure heater and mixed Close, to improve condensate water water temperature.The mixed condensate carrys out supply mains 15 after being boosted through water pump into condensate, warp Enter coagulation hydroenergy backwater house steward 12 after residual neat recovering system, the condensate that can then return to this grade of low-pressure heater outlet is total The positions such as pipe.

Condensate carrys out supply mains 15 can also be connected with heat supply network return pipe, and coagulation hydroenergy backwater house steward 12 connects with hot net water feed pipe Connect, such fume afterheat can be additionally used in heat supply network heat supply.

The method of work of present system includes：

When high-temperature flue gas in exhaust gases passes 17 flows through air preheater 9, with flowing through condensate air in air duct 20 Channel heat exchanger 19 enters the air heat-exchange of air preheater 9 after being heated, reduce flue-gas temperature, air themperature is further carried It is high；

When heat smoke after the air preheater 9 in exhaust gases passes 17 flows through condensate chimney heat exchanger 8, heat is passed The condensate for flowing through condensate chimney heat exchanger 8 is passed, flue-gas temperature is further reduced, condensing water temperature is improved；Absorb The condensate that the temperature of fume afterheat is higher returns to therrmodynamic system through coagulation hydroenergy backwater house steward 12, and fume afterheat is utilized.

Air duct heat exchanger condensate bypass valve 10 is surveyed according to chimney heat exchanger exit gas temperature sensor 16 Value controls aperture.When the flue-gas temperature measured by chimney heat exchanger exit gas temperature sensor 16 goes out higher than chimney heat exchanger When mouth flue-gas temperature setting the 1st is worth, the aperture of air duct heat exchanger condensate bypass valve 10 increase, so that survey is reduced or eliminated Deviation between the value of chimney heat exchanger exit gas temperature and chimney heat exchanger exit gas temperature setting the 1st of amount.

Condensate air duct heat exchanger inlet regulating valve 18 coordinates air duct heat exchanger condensate bypass valve 10 Regulation.When the flue-gas temperature measured by chimney heat exchanger exit gas temperature sensor 16 is higher than chimney heat exchanger exiting flue gas temperature When degree setting the 1st is worth, the aperture of condensate air duct heat exchanger inlet regulating valve 18 reduces, so that the flue of measurement is reduced or eliminated Deviation between heat exchanger exit flue-gas temperature and the value of chimney heat exchanger exit gas temperature setting the 1st.Vice versa.

As an improvement, air duct heat exchanger condensate bypass valve 10 and the water inlet of condensate air duct heat exchanger are adjusted Save valve 18 can also control aperture according to the measured value of condensate chimney heat exchanger inlet water temperature sensor 7, to be controlled under special operation condition The entrance of condensate chimney heat exchanger 8 processed condenses water temperature, prevents condensate chimney heat exchanger 8 from occurring serious low-temperature corrosion and stifled Ash.

When the condensing water temperature measured by condensate chimney heat exchanger inlet water temperature sensor 7 is less than condensate flue heat exchange During device inlet water temperature setting value 1, the aperture of air duct heat exchanger condensate bypass valve 10 increase, so that measurement is reduced or eliminated Condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1 between deviation.Otherwise also So.

Condensate air duct heat exchanger inlet regulating valve 18 coordinates air duct heat exchanger condensate bypass valve 10 Regulation.When the condensing water temperature measured by condensate chimney heat exchanger inlet water temperature sensor 7 is less than condensate chimney heat exchanger During inlet water temperature setting value 1, the aperture of condensate air duct heat exchanger inlet regulating valve 18 reduces, so that measurement is reduced or eliminated Deviation between condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1.Vice versa.

As an improvement, the wall temperature in order to reliably control condensate chimney heat exchanger 8, prevents condensate chimney heat exchanger 8 from sending out Raw serious low-temperature corrosion and stifled ash, the present invention can be recycled for adjusting condensate flue heat exchange by chimney heat exchanger condensate The entrance of device 8 condenses water temperature.

Chimney heat exchanger condensate recycles survey of the regulating valve 11 according to condensate chimney heat exchanger inlet water temperature sensor 7 Value controls aperture.When the condensing water temperature measured by condensate chimney heat exchanger inlet water temperature sensor 7 is less than condensation shredded tobacco for water pipes During road heat exchanger entrance water temperature setting value 2, chimney heat exchanger condensate recycling regulating valve 11 aperture increase, to be reduced or eliminated Deviation between the condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 2 of measurement.Instead It is as the same.

Chimney heat exchanger condensate recirculation pump 13 can coagulate according to water pressure is pumped out higher than condensate in supply mains 15 The difference setting value for bearing water pressure carries out automatic or manual variable frequency adjustment, when the actual measurement difference is less than the difference setting value, Water pump operation frequency is improved, and the difference and difference setting value deviation of the pressure are reduced or eliminated.Vice versa.

As an improvement, in order to which the preheated air ability and fume afterheat that improve condensate air duct heat exchanger 19 utilize effect Benefit, the present invention is recycled for the condensate that control enters condensate air duct heat exchanger 19 using cigarette air channel heat exchanger condensate Inlet water temperature, so as to control the entering air temperature of air preheater 9 or the condensation water inlet water of condensate chimney heat exchanger 8 Temperature.

Cigarette air channel heat exchanger condensate recycles survey of the regulating valve 14 according to air preheater inlet air temperature sensor 5 Value controls aperture.When the air themperature measured by air preheater inlet air temperature sensor 5 enters less than air preheater When mouth air themperature setting the 1st is worth, cigarette air channel heat exchanger condensate recycling regulating valve 14 aperture increase, so that survey is reduced or eliminated Deviation between the value of air preheater entering air temperature and air preheater entering air temperature setting the 1st of amount.Otherwise also So.As an improvement, cigarette air channel heat exchanger condensate recycling regulating valve 14 can also be according to condensate chimney heat exchanger entrance The condensate inlet water temperature control aperture for the condensate chimney heat exchanger that cooling-water temperature sensor 7 is measured；When condensate chimney heat exchanger Condensate inlet water temperature when being less than setting value, cigarette air channel heat exchanger condensate recycling regulating valve 14 aperture increase, to reduce Or eliminate deviation.Vice versa.

As an improvement, the air themperature in order to further improve air inlet preheater 9 when environment temperature is relatively low, Yi Jigai Combustibility when kind boiler start/ stop and underrun, flows through the air after air duct heat exchanger 19 and first passes through one-level steam Air heater 3 and second steam air heater 4 enter back into air preheater 9 after heating；Heat steam empty in one-level steam Hot-air heater 3 and the vapour of second steam air heater 4, which are surveyed, to be condensed into water after the air for transferring heat to air side and returns to accordingly Recovery system is utilized.

Main air heats the measured value and sky according to chimney heat exchanger exit gas temperature sensor 16 into steam control valve 1 The measured value of air preheater inlet air temperature sensor 5 controls aperture after integrating computing.When air preheater intake air temperature Spend sensor 5 measured by air themperature less than air preheater entering air temperature setting the 2nd be worth when, main air heat into The aperture of steam control valve 1 increases, empty with air preheater entering air temperature and air preheater entrance that measurement is reduced or eliminated Deviation between the value of temperature degree setting the 2nd.When the measured value of chimney heat exchanger exit gas temperature sensor 16 is changed higher than flue When hot device exit gas temperature setting the 2nd is worth, air is heated to be reduced into the aperture of steam control valve 1, so that the cigarette of measurement is reduced or eliminated Deviation between road heat exchanger exit flue-gas temperature and the value of chimney heat exchanger exit gas temperature setting the 2nd.Vice versa.

Secondary air heats the measured value and sky according to chimney heat exchanger exit gas temperature sensor 16 into steam control valve 2 The measured value of air preheater inlet air temperature sensor 5 controls aperture after integrating computing.When air preheater intake air temperature Spend sensor 5 measured by air themperature less than air preheater entering air temperature setting the 3rd be worth when, secondary air heat into The aperture of steam control valve 2 increases, empty with air preheater entering air temperature and air preheater entrance that measurement is reduced or eliminated Deviation between the value of temperature degree setting the 3rd.When the measured value of chimney heat exchanger exit gas temperature sensor 16 is changed higher than flue When hot device exit gas temperature setting the 3rd is worth, secondary air is heated to be reduced into the aperture of steam control valve 2, so that measurement is reduced or eliminated Chimney heat exchanger exit gas temperature and chimney heat exchanger exit gas temperature setting the 3rd value between deviation.Vice versa.

Chimney heat exchanger exit gas temperature of the present invention sets the 1st value and set less than chimney heat exchanger exit gas temperature Fixed 1~20 DEG C of 2nd value, the value of chimney heat exchanger exit gas temperature setting the 2nd is less than chimney heat exchanger exit gas temperature Set 1~20 DEG C of the 3rd value.The chimney heat exchanger exit gas temperature sets the 1st value, the 2nd value, the 3rd value preferred scope as 50 ~160 DEG C, the concrete condition setting such as coal and heat-transfer surface design can be used according to boiler.

The present invention will allow to properly increase chimney heat exchanger exiting flue gas when air preheater entering air temperature is too low Temperature, ensures the equipment safety of air preheater 9 in the way of sacrificing efficiency, and air preheater entering air temperature is lower, it is allowed to Chimney heat exchanger exit gas temperature it is higher.

It should be noted last that, the above embodiments are merely illustrative of the technical solutions of the present invention and it is unrestricted.Although ginseng The present invention is described in detail according to embodiment, it will be understood by those within the art that, to the technical side of the present invention Case is modified or equivalent substitution, and without departure from the spirit and scope of technical solution of the present invention, it all should cover in the present invention Right among.

Claims

1. a kind of air preheat and smoke waste heat utilization system, including：Exhaust gases passes (17), air duct (20), air preheat Device (9), condensate chimney heat exchanger (8) and condensate air duct heat exchanger (19), it is characterised in that also include：Condensate Come supply mains (15), coagulation hydroenergy backwater house steward (12)；

The exhaust gases passes (17) and air duct (20) are connected with air preheater (9)；

The condensate chimney heat exchanger (8) is arranged on the exhaust gases passes (17) after air preheater (9) along flue gas flow direction；Institute Condensate air duct heat exchanger (19) is stated to be arranged on the air duct (20) before air preheater (9) along air flow；

The entrance of the condensate of the condensate air duct heat exchanger (19) carrys out supply mains (15) with condensate and is connected；It is described solidifying The outlet for bearing water chimney heat exchanger (8) is connected with coagulation hydroenergy backwater house steward (12)；The condensate air duct heat exchanger (19) Condensate outlet and condensate chimney heat exchanger (8) entrance respectively with condensing shredded tobacco for water pipes air channel heat exchanger connecting tube (6) Two ends are connected；

The condensate comes between supply mains (15) and condensation shredded tobacco for water pipes air channel heat exchanger connecting tube (6), is exchanged heat by air duct Device condensate shunt valve is connected, and air duct heat exchanger condensate is provided with the air duct heat exchanger condensate shunt valve Bypass valve (10).

2. air preheat according to claim 1 and smoke waste heat utilization system, it is characterised in that the exhaust gases passes (17) chimney heat exchanger exit gas temperature sensor is provided with the export pipeline of condensate chimney heat exchanger (8) (16)；The condensate come on supply mains (15) be provided with after air duct heat exchanger condensate shunt valve tie point it is solidifying Bear water air duct heat exchanger inlet regulating valve (18).

3. air preheat according to claim 1 and smoke waste heat utilization system, it is characterised in that in the condensation shredded tobacco for water pipes In air channel heat exchanger connecting tube (6), tie point and condensate chimney heat exchanger with air duct heat exchanger condensate shunt valve (8) condensate chimney heat exchanger inlet water temperature sensor (7) is provided between；The coagulation hydroenergy backwater house steward (12) and condensate Connected between cigarette air channel heat exchanger connecting tube (6) by chimney heat exchanger condensate recirculating water pipe；The chimney heat exchanger condenses One end of water recirculation pipe is connected to condensate chimney heat exchanger inlet water temperature in condensation shredded tobacco for water pipes air channel heat exchanger connecting tube (6) and passed Optional position before sensor (7)；On chimney heat exchanger condensate recirculating water pipe flue heat exchange is disposed with along condensation current direction Device condensate recirculation pump (13) and chimney heat exchanger condensate recycling regulating valve (11).

4. air preheat according to claim 3 and smoke waste heat utilization system, it is characterised in that the air duct (20) air preheater intake air temperature is provided between air preheater (9) and condensate air duct heat exchanger (19) Spend sensor (5)；The condensate comes supply mains (15) and chimney heat exchanger condensate recirculating water pipe and passes through cigarette air channel heat exchanger Condensate recirculating water pipe is connected；One end of the cigarette air channel heat exchanger condensate recirculating water pipe is connected to chimney heat exchanger condensate Between recirculation pipe upper flue heat exchanger condensate recirculation pump (13) and chimney heat exchanger condensate recycling regulating valve (11), The other end, which is connected to condensate, to be come supply mains (15) upper air passage heat exchanger condensate shunt valve and condensate and carrys out supply mains (15) before tie point；The heat exchanger condensate recycling of cigarette air channel is provided with the cigarette air channel heat exchanger condensate recirculating water pipe Regulating valve (14).

5. air preheat according to claim 4 and smoke waste heat utilization system, it is characterised in that the air duct (20) one-level is provided between air preheater inlet air temperature sensor (5) and condensate air duct heat exchanger (19) Steam air heater (3) and second steam air heater (4)；One-level steam air heater (3) and second steam air The steam side of heater (4) is connected with respective external vapour source steam inlet pipe respectively, the external vapour of one-level steam air heater (3) Source steam inlet pipe is provided with main air and heated into steam control valve (1)；The external vapour source steam inlet pipe of second steam air heater (4) Secondary air is provided with to heat into steam control valve (2).

6. it is a kind of based on more than any air preheats of claim 1-4 and the air preheat of smoke waste heat utilization system and flue gas Heat utilization method, comprises the following steps：

The condensate for flowing through air duct heat exchanger (19) comes the condensate in supply mains (15) and the sky in air duct (20) Gas exchanges heat, and condensate transfers heat to air, condensing water temperature reduction, air themperature rise；

High-temperature flue gas in the exhaust gases passes (17) flows through air preheater (9), with flowing through condensate in air duct (20) Air duct heat exchanger (19) enters the air heat-exchange of air preheater (9) after being heated, reduce flue-gas temperature, air themperature Improve；

Heat smoke of the air preheater (9) afterwards in exhaust gases passes (17) flows through condensate chimney heat exchanger (8), and heat is passed The condensate for flowing through condensate chimney heat exchanger (8) is passed, flue-gas temperature is reduced, condensing water temperature is improved；Absorb flue gas The condensate that the temperature of waste heat is higher returns to therrmodynamic system through coagulation hydroenergy backwater house steward (12), and fume afterheat is utilized；

The air duct heat exchanger condensate bypass valve (10) is according to chimney heat exchanger exit gas temperature sensor (16) measured value control aperture；Flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor (16) is higher than cigarette Road heat exchanger exit flue-gas temperature setting the 1st is worth, air duct heat exchanger condensate bypass valve (10) aperture increase, to subtract It is inclined between chimney heat exchanger exit gas temperature that is small or eliminating measurement and the value of chimney heat exchanger exit gas temperature setting the 1st Difference；Or, the flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor (16) goes out less than chimney heat exchanger Mouth flue-gas temperature setting the 1st is worth, and air duct heat exchanger condensate bypass valve (10) aperture reduces；

Condensate air duct heat exchanger inlet regulating valve (18) coordinates air duct heat exchanger condensate bypass valve (10) Regulation；Flue-gas temperature measured by the chimney heat exchanger exit gas temperature sensor (16) exports cigarette higher than chimney heat exchanger Temperature degree setting the 1st is worth, and condensate air duct heat exchanger inlet regulating valve (18) aperture reduces, so that measurement is reduced or eliminated Deviation between chimney heat exchanger exit gas temperature and the value of chimney heat exchanger exit gas temperature setting the 1st；Or, the cigarette Flue-gas temperature measured by road heat exchanger exit flue-gas temperature sensor (16) is set less than chimney heat exchanger exit gas temperature 1st value, the increase of condensate air duct heat exchanger inlet regulating valve (18) aperture.

7. air preheat according to claim 6 and fume afterheat Application way, it is characterised in that the air duct is changed Hot device condensate bypass valve (10) and condensate air duct heat exchanger inlet regulating valve (18) are changed according to condensate flue The measured value control aperture of hot device inlet water temperature sensor (7), the entrance of control condensate chimney heat exchanger (8) condenses water temperature, Prevent condensate chimney heat exchanger (8) from occurring serious low-temperature corrosion and stifled ash；

Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor (7) is less than condensate flue heat exchange Device inlet water temperature setting value 1, air duct heat exchanger condensate bypass valve (10) aperture increase, so that measurement is reduced or eliminated Condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1 between deviation；Or, institute State the condensing water temperature measured by condensate chimney heat exchanger inlet water temperature sensor (7) and be higher than condensate chimney heat exchanger entrance Water temperature setting value 1, air duct heat exchanger condensate bypass valve (10) aperture reduces；

The condensate air duct heat exchanger inlet regulating valve (18) coordinates air duct heat exchanger condensate bypass valve (10) adjust；Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor (7) is less than condensation shredded tobacco for water pipes Road heat exchanger entrance water temperature setting value 1, condensate air duct heat exchanger inlet regulating valve (18) aperture reduces, to reduce or disappear Except the deviation between the condensate chimney heat exchanger inlet water temperature and condensate chimney heat exchanger inlet water temperature setting value 1 of measurement； Or, the condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor (7) is changed higher than condensate flue Hot device inlet water temperature setting value 1, the increase of condensate air duct heat exchanger inlet regulating valve (18) aperture.

8. air preheat according to claim 6 and fume afterheat Application way, it is characterised in that pass through chimney heat exchanger The entrance that condensate is recycled for adjusting condensate chimney heat exchanger (8) condenses water temperature；

Chimney heat exchanger condensate recycles survey of the regulating valve (11) according to condensate chimney heat exchanger inlet water temperature sensor (7) Value controls aperture；Condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor (7) is less than condensation Shredded tobacco for water pipes road heat exchanger entrance water temperature setting value 2, chimney heat exchanger condensate recycling regulating valve (11) aperture increase, with reduce or Eliminate inclined between the condensate chimney heat exchanger inlet water temperature measured and condensate chimney heat exchanger inlet water temperature setting value 2 Difference；Or, the condensing water temperature measured by the condensate chimney heat exchanger inlet water temperature sensor (7) is higher than condensate flue Heat exchanger entrance water temperature setting value 2, chimney heat exchanger condensate recycling regulating valve (11) aperture reduces.

9. air preheat according to claim 6 and fume afterheat Application way, it is characterised in that using the heat exchange of cigarette air channel Device condensate is recycled for the condensate inlet water temperature that control enters condensate air duct heat exchanger (19), so as to control air The entering air temperature of preheater (9) or the condensate inlet water temperature of condensate chimney heat exchanger (8)；

Cigarette air channel heat exchanger condensate recycles survey of the regulating valve (14) according to air preheater inlet air temperature sensor (5) Value controls aperture；Air themperature measured by the air preheater inlet air temperature sensor (5) is less than air preheat Device entering air temperature setting the 1st is worth, cigarette air channel heat exchanger condensate recycling regulating valve (14) aperture increase, to reduce or disappear Except the deviation between the value of air preheater entering air temperature and air preheater entering air temperature setting the 1st of measurement；Afterwards Person, the air themperature measured by the air preheater inlet air temperature sensor (5) is higher than air preheater intake air Temperature setting the 1st is worth, and heat exchanger condensate recycling regulating valve (14) aperture in cigarette air channel reduces；

Or, cigarette air channel heat exchanger condensate recycling regulating valve (14) is according to condensate chimney heat exchanger inlet water temperature sensor (7) the condensate inlet water temperature control aperture of the condensate chimney heat exchanger of measurement；The condensation of the condensate chimney heat exchanger Water inlet water temperature is less than setting value, cigarette air channel heat exchanger condensate recycling regulating valve (14) aperture increase, to be reduced or eliminated Deviation；Or, the condensate inlet water temperature of the condensate chimney heat exchanger is higher than setting value, and cigarette air channel heat exchanger condensate is again Circulating regulation valve (14) aperture reduces.

10. a kind of air preheat and fume afterheat profit based on air preheat described in claim 5 and smoke waste heat utilization system With method, comprise the following steps：

11. air preheat according to claim 10 and fume afterheat Application way, it is characterised in that the air duct Heat exchanger condensate bypass valve (10) and condensate air duct heat exchanger inlet regulating valve (18) are according to condensate flue The measured value control aperture of heat exchanger entrance cooling-water temperature sensor (7), the entrance condensate of control condensate chimney heat exchanger (8) Temperature, prevents condensate chimney heat exchanger (8) from occurring serious low-temperature corrosion and stifled ash；

12. air preheat according to claim 10 and fume afterheat Application way, it is characterised in that pass through flue heat exchange The entrance that device condensate is recycled for adjusting condensate chimney heat exchanger (8) condenses water temperature；

13. air preheat according to claim 10 and fume afterheat Application way, it is characterised in that changed using cigarette air channel Hot device condensate is recycled for the condensate inlet water temperature that control enters condensate air duct heat exchanger (19), so as to control sky The entering air temperature of air preheater (9) or the condensate inlet water temperature of condensate chimney heat exchanger (8)；

14. air preheat according to claim 10 and fume afterheat Application way, it is characterised in that flow through air duct Air after heat exchanger (19) is first passed through after one-level steam air heater (3) and second steam air heater (4) heating again Air inlet preheater (9)；Steam is heated to survey in one-level steam air heater (3) and second steam air heater (4) vapour Water is condensed into after the air for transferring heat to air side and returns to corresponding recovery system utilization；

The main air heats the measured value according to chimney heat exchanger exit gas temperature sensor (16) into steam control valve (1) Combination with the measured value of air preheater inlet air temperature sensor (5) controls aperture；The air preheater entrance is empty Air themperature measured by gas temperature sensor (5) is worth less than air preheater entering air temperature setting the 2nd, and main air adds Heat enters the increase of steam control valve (1) aperture, so that the air preheater entering air temperature and air preheater of measurement is reduced or eliminated Deviation between the value of entering air temperature setting the 2nd；The measured value of the chimney heat exchanger exit gas temperature sensor (16) It is worth higher than chimney heat exchanger exit gas temperature setting the 2nd, air is heated to be reduced into steam control valve (1) aperture, to reduce or disappear Except the deviation between the value of chimney heat exchanger exit gas temperature and chimney heat exchanger exit gas temperature setting the 2nd of measurement；Or Person, the air themperature measured by the air preheater inlet air temperature sensor (5) is higher than air preheater intake air Temperature setting the 2nd is worth, and main air is heated to be reduced into steam control valve (1) aperture；The chimney heat exchanger exit gas temperature is passed The measured value of sensor (16) is worth less than chimney heat exchanger exit gas temperature setting the 2nd, and air is heated into steam control valve (1) aperture Increase；

The secondary air heats the measured value according to chimney heat exchanger exit gas temperature sensor (16) into steam control valve (2) Combination with the measured value of air preheater inlet air temperature sensor (5) controls aperture；The air preheater entrance is empty Air themperature measured by gas temperature sensor (5) is worth less than air preheater entering air temperature setting the 3rd, and secondary air adds Heat enters the increase of steam control valve (2) aperture, so that the air preheater entering air temperature and air preheater of measurement is reduced or eliminated Deviation between the value of entering air temperature setting the 3rd；The measured value of the chimney heat exchanger exit gas temperature sensor (16) It is worth higher than chimney heat exchanger exit gas temperature setting the 3rd, secondary air is heated to be reduced into steam control valve (2) aperture, to reduce Or eliminate inclined between the chimney heat exchanger exit gas temperature of measurement and the value of chimney heat exchanger exit gas temperature setting the 3rd Difference；

Or, the air themperature measured by the air preheater inlet air temperature sensor (5) enters higher than air preheater Mouth air themperature setting the 3rd is worth, and secondary air is heated to be reduced into steam control valve (2) aperture；The chimney heat exchanger exiting flue gas The measured value of temperature sensor (16) is worth less than chimney heat exchanger exit gas temperature setting the 3rd, and secondary air is heated to be adjusted into vapour Save the increase of valve (2) aperture.