The corrosion-resistant heat pipe flue gas waste heat recovery system of a kind of coal-fired plant
Technical field
The utility model relates to coal-fired plant's energy-conserving and environment-protective technical field, particularly, relates to the corrosion-resistant heat pipe flue gas waste heat recovery system of a kind of coal-fired plant.
Background technology
In recent years, China's energy demand is rigidity and increases, and receives restriction of domestic resource guarantee ability and environmental carrying capacity and global energy safety and reply climate change effect, and the resource environment constraint is strengthened day by day, and the situation that energy-saving and emission-reduction face is very severe.
Plan the requirement of the target for energy-saving and emission-reduction that proposes according to China " 12 ".Aspect energy-conservation, by 2015, the ten thousand yuan of GDP energy consumptions in the whole nation dropped to 0.869 ton of standard coal (by calculation of price in 2005), and 1.034 tons of standard coals than 2010 descend 16%, during " 12 ", realize 6.7 hundred million tons of standard coals of energy savings.Aspect reduction of discharging, by 2015, national COD and sulfur dioxide (SO2) emissions total amount were controlled at 2347.6 ten thousand tons, 2086.4 ten thousand tons respectively, descend 8% respectively than 2010; Whole nation ammonia nitrogen and discharged nitrous oxides total amount are controlled at 238.0 ten thousand tons, 2046.2 ten thousand tons respectively, descend 10% respectively than 2010.The realization of country's " 12 " object of planning needs national all trades and professions to respond actively, and deeply taps the latent power, and strengthens the energy-saving and emission-reduction working dynamics, especially as energy consumption rich and influential family's power industry.And the consumption of power industry boiler fired coal occupies very big ratio in whole national energy consumption, Just because of this, and various apparatus for energy recovery being employed more and more widely in boiler combustion system.
At present, can know from each item heat loss of boiler that heat loss due to exhaust gas is wherein maximum one, is generally 5 ~ 8% of boiler efficiency, and along with the increase of the boiler operatiopn time limit, this loss even higher can reach about 10 ~ 15%.Therefore, flue gas waste heat recovery technology is the most obvious, the fastest power-saving technology of energy-saving benefit.It recycles portion of energy in the flue gas loss, improves boiler efficiency with this, and then improves energy utilization rate, reduces production costs, and also is simultaneously to reduce pollutant emission direct, the most economic means of protection environment.In addition, according to the requirement of national environmental protection policy, coal-burning boiler must possess flue gas desulphurization system.Up to now; That has used both at home and abroad has several flue gas desulfurization techniques; But the large thermal power plant units gas desulfurization is main with lime stone-gypsum wet technology all, because its desulfuration efficiency is high, good stability, and has become the first-selected technology of China's coal-fired plant flue gas desulfurization.
But; Running temperature is lower in lime stone-gypsum wet sulfur removal technology, and is far away from the boiler design exhaust gas temperature, in desulphurization system, needs usually to adopt the mode of water spray to cool off the cigarette temperature; So not only lost the heat of flue gas between exhaust gas temperature and the desulfurization temperature; And increased the water consumption of power plant, and also having increased the moisture content in the clean flue gas simultaneously, the increase of smoke discharge amount also influences the environmental protection situation of power plant's surrounding environment; Can know by above analysis; Carry out in the process of wet desulphurization at coal-burning boiler, the flue gas heat of boiler export does not basically all have to recycle, and has increased the pressure of operation energy consumption and environment protection emission; Therefore, need a kind of flue gas cooling technology to solve the problem of waste heat recovery and environment protection emission.
It is thus clear that; This situation according to power industry coal-burning boiler actual motion; Need a kind of flue gas cooling residual heat recovery technology of research and development, reclaim the boiler design exhaust gas temperature, thereby reach power plant's energy-saving and emission-reduction and the requirement that reduces environmental pollution to the heat between the sulfur removal technology temperature.Therefore, adopt the flue gas low-temperature heat recovery technology, make full use of the waste heat before flue gas enters the absorption tower, become an important topic of the current energy-saving and emission-reduction of power system.
The flue gas low-temperature heat recovery is carried out in zone before fire coal boiler fume system of thermal power plant desulfurizing tower, and flue-gas temperature can drop to below the acid dew point, so flue gas waste heat recovery equipment corrosion-resistant or the influence of cohering dust stratification are the main technical issues that need to address.At present, in the flue gas waste heat recovery technology of this area applications, normally adopt improved low-pressure coal saver technology, i.e. the spiral finned heat exchanger technology; And because of its system connects different other application technologies that develop out with endless form, like system for deep cooling and waste heat recovery of smoke gas in boiler (can be the patent documentation of CN101709879A referring to publication number specifically).
This technological exemplary systems; As shown in Figure 1, comprise chimney 1, FGD go out baffle plate 2 (promptly two multiple damper door), No. 1 absorption tower 3, boiler 4, deduster 5, air-introduced machine 6, FGD enter baffle plate 7 (promptly two multiple damper door), booster fan 8, gas cooler 9, oxidation fan 10, low pressure (LP) cylinder 11, generator 12, JD6 13 (being the #6 low-pressure heater), JD7 (being the #7 low-pressure heater) 14, JD8 (being the #8 low-pressure heater) 15, condensate pump 16 and condenser 17; Boiler 4, deduster 5, air-introduced machine 6, FGD enter baffle plate 7, booster fan 8, gas cooler 9 and No. 1 absorption tower 3 are connected through pipeline successively; Oxidation fan 10, No. 1 absorption tower 3, FGD go out baffle plate 2 and chimney 1 are connected through pipeline successively; Intermediate pressure cylinder, low pressure (LP) cylinder 11, condenser 17, condensate pump 16, JD8 15, JD7 14, JD6 13 and JD1 (being the #1 low-pressure heater) are connected through pipeline successively, and generator 12 is snap-fit attachment to low pressure (LP) cylinder 11 rotors; Between JD8 15 and JD7 14, draw a pipeline, be connected to gas cooler 9; And, draw another pipeline from gas cooler 9, be connected between JD7 14 and the JD6 13; Between JD8 15 and gas cooler 9, first valve is housed; Between JD7 14 and JD6 13, second valve is housed; Between gas cooler 9 and JD6 13, the 3rd valve is housed.
In system shown in Figure 1; Be in the flue before booster fan 8 and No. 1 absorption tower 3; Increase by a cover gas-liquid formula spiral finned heat exchanger (cigarette-water-to-water heat exchanger), its water side is connected in parallel on the steam turbine heat regenerative system grade low-pressure heater, from low import extension or the whole condensed water of adding of certain level; Be sent to the cigarette water-to-water heat exchanger and absorb smoke exhaust heat; Reduce exhaust gas temperature, and self be heated, return the low-pressure heater system again after the temperature that raises, enter into after the low outlet that adds of this grade compiles with remaining condensate that next stage is low to be added.Because its system is connected in parallel among the heater loop, the effect of instead of part low-pressure heater is so also be a part (referring to Waigaoqiao of Shaihai the 3rd power plant flue gas waste heat recovery Project Summary Report) of thermodynamic system of steam tur.
Above-mentioned technology is on the basis of traditional low-pressure coal saver, to develop, and mainly from the material and the heat-setting coolant-temperature gage aspect of spiral fin coil, has carried out following improvement:
⑴ adopt resistant material ND steel (being the 09CrCuSb steel) as heating surface tubing.But facts have proved that ND steel corrosion fatigue life is merely 3 ~ 4 times of ordinary carbon steel, and owing in the flue gas environment of complicacy, not only have SO
3 -, SO
4 -, also have a F
-, Cl
-, under the condition of polyacid corrosion, the ND steel can only delay corrosion, can not resist corrosion like this;
⑵ heat-setting water has been adjusted under the acid dew point and the low speed corrosion area between on the water dew point on acid dew point.This regional temperature interval is less; When the boiler variable parameter operation, condensing water flow is regulated bigger, departs from the optimal economic operating mode of whole back heating system easily; Cause the energy-saving benefit of waste heat recovery to descend, the branch throughflow of condensate also influences the security of operation of low-pressure heater easily simultaneously.In addition, when power plant used coal and changes, the low speed corrosion area was with the off-design operating mode, and the range of temperature of former design condensate dry point is difficult to the adaptation condition adjustment.
And the low-pressure coal saver technology still has some problems to exist, for example:
⑴ low-pressure coal saver technology heating working medium is single.Owing to get into the working medium temperature of low-pressure coal saver system certain requirement is arranged, the adjusting surplus is less, when choosing working medium, can only draw condensate as the water source in the position of certain low-pressure heater import or export from the steam turbine condensate system.That is to say that low-pressure coal saver can't directly heat other working medium, other more need in the system of waste heat to power plant with the heat recovery of flue gas;
⑵ low-pressure coal saver techniques make use be that the sensible heat transfer mode reclaims heat, specific latent heat transmits organic efficiency will hang down several magnitude, the inlet temperature of heating working medium is had relatively high expectations simultaneously; Because the high inlet temperature of refrigerant has limited the heat transfer temperature difference of heat transmission equipment, therefore, reclaiming under the identical situation of heat; Less heat transfer temperature difference; Take bigger heat exchange area when lower heat transfer efficiency has determined to need design, not only increased arrangement space, also increased equipment investment;
⑶ low-pressure coal saver still adopts spiral fin coil in order to save arrangement space, and in the smoke condensation zone existence of cohering dust stratification is arranged unavoidably; These dust stratifications can be difficult to cleaning in fin interval deposition usually; Also be difficult to remove even soot blower is installed, in the course of time, will influence heat exchange efficiency; Acid concentration increases around also can causing tube wall, and the corrosion aggravation strengthens;
⑷ low-pressure coal saver is the hosepipe row who is connected by the import and export header, and as a whole formula heat exchanger if tube bank has corrosion leakage takes place a bit; Whole system must quit work immediately, if whole system in time do not isolate again, a large amount of carbonated drink is bled in the middle of the flue gas system; Cause follow-up equipment dust stratification, corrosion; The blower fan load increases, and power consumption increases, and causes desulphurization system to move when serious.
In sum, in the process that realizes the utility model, the inventor finds to exist at least in the prior art following defective:
⑴ energy saving is poor: carry out in the process of wet desulphurization at coal-burning boiler, the flue gas heat of boiler export does not basically all have to recycle, and has also increased operation energy consumption;
In the low-pressure coal saver technology, because low-pressure coal saver can't directly heat other working medium, also just can't other more need in the system of waste heat to power plant with the heat recovery of flue gas; Utilize the sensible heat transfer mode to reclaim heat, specific latent heat transmits organic efficiency will hang down several magnitude; In order to save arrangement space, still adopt spiral fin coil, the existence of cohering dust stratification is arranged in the smoke condensation zone unavoidably and be difficult to cleaning, influence heat exchange efficiency;
⑵ the feature of environmental protection is poor: carry out in the process of wet desulphurization at coal-burning boiler, operation energy consumption and environment protection emission pressure are all bigger;
⑶ cost is high: in the low-pressure coal saver technology, utilize the sensible heat transfer mode to reclaim heat, the inlet temperature of heating working medium is had relatively high expectations; And the high inlet temperature of refrigerant has limited the heat transfer temperature difference of heat transmission equipment; Therefore, reclaiming under the identical situation of heat less heat transfer temperature difference; Lower heat transfer efficiency need be taked bigger heat exchange area, increases equipment investment;
In addition, in order to save arrangement space, still adopt spiral fin coil, the existence of cohering dust stratification is arranged in the smoke condensation zone unavoidably and be difficult to and remove, can cause tube wall acid concentration increase on every side, the corrosion aggravation strengthens, and has increased maintenance of equipment and replacement cost;
⑷ poor reliability: in the low-pressure coal saver technology, the hosepipe that the import and export header connects is arranged as a whole formula heat exchanger, if tube bank has corrosion leakage takes place a bit, and whole system must quit work immediately;
Simultaneously, if whole system is not in time isolated, a large amount of carbonated drink is bled in the middle of the flue gas system, cause follow-up equipment dust stratification, corrosion, the blower fan load increases, and power consumption increases, and causes desulphurization system to move when serious;
⑸ take up room greatly: in the low-pressure coal saver technology, utilize the sensible heat transfer mode to reclaim heat, the inlet temperature of heating working medium is had relatively high expectations; Because the high inlet temperature of refrigerant has limited the heat transfer temperature difference of heat transmission equipment; Therefore, reclaiming under the identical situation of heat less heat transfer temperature difference; Lower heat transfer efficiency need be taked bigger heat exchange area, increases arrangement space.
The utility model content
The purpose of the utility model is, to the problems referred to above, proposes the corrosion-resistant heat pipe flue gas waste heat recovery system of a kind of coal-fired plant, with realize good energy saving property, the feature of environmental protection is good, cost is low, good reliability, little and advantage applied range take up room.
For realizing above-mentioned purpose; The technical scheme that the utility model adopts is: the corrosion-resistant heat pipe flue gas waste heat recovery system of a kind of coal-fired plant comprises the boiler, deduster, air-introduced machine, booster fan, corrosion resistant heat exchange of heat pipe, desulfurizing tower and the chimney that are connected through pipeline successively.
Further, said corrosion resistant heat exchange of heat pipe comprises the enamel hot pipe heat exchanger or is coated with the heat exchange of heat pipe of corrosion resistant coating.
Further, in the vertical direction, said corrosion resistant heat exchange of heat pipe comprises the upper and lower, and top is the low-temperature receiver working medium side, and the bottom is a fume side, between fume side and low-temperature receiver working medium side, is provided with dividing plate;
In said fume side, be provided with the fume side outlet that is used for the fume side inlet that is connected with booster fan and is used for being connected with desulfurizing tower;
In said low-temperature receiver working medium side, the low-temperature receiver working medium side outlet that is provided with the low-temperature receiver working medium side inlet that is used to import low-temperature receiver working medium and is used to export low-temperature receiver working medium.
Further, the corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant also comprises the bypass flue; Said bypass flue is drawn between self-induced-air machine and the booster fan, is connected between desulfurizing tower and the chimney.
Further; The corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant; Also comprise first to fourth baffle plate, said first baffle plate is connected between desulfurizing tower and the chimney, and second baffle is connected between deduster and the blower fan; The 3rd baffle plate is arranged in the bypass flue, and the 4th baffle plate is arranged between bypass flue and the booster fan.
Further, in said boiler,, cooperate to be provided with air preheater near the pipeline that is connected to deduster.
Simultaneously, another technical scheme of the utility model employing is: the corrosion-resistant heat pipe flue gas waste heat recovery method of coal-fired plant that the corrosion-resistant heat pipe flue gas waste heat recovery system of a kind of and above-described coal-fired plant matches comprises:
In the flue system of coal-fired plant, set up the corrosion resistant heat exchange of heat pipe, the heat and the steam of flue system is recycled;
Between the air-introduced machine and booster fan of flue system, draw the bypass flue, be connected between the desulfurizing tower and chimney of flue system.
Further, said corrosion resistant heat exchange of heat pipe is equipped with between the booster fan and desulfurizing tower of flue system, and heat in the flue gas between booster fan and the desulfurizing tower and steam are recycled.
Further, said corrosion resistant heat exchange of heat pipe comprises the enamel hot pipe heat exchanger or is coated with the heat exchange of heat pipe of corrosion resistant coating;
In the vertical direction, said corrosion resistant heat exchange of heat pipe comprises the upper and lower, and top is the low-temperature receiver working medium side, and the bottom is a fume side, between fume side and low-temperature receiver working medium side, is provided with dividing plate;
In said fume side, be provided with the fume side outlet that is used for the fume side inlet that is connected with booster fan and is used for being connected with desulfurizing tower;
In said low-temperature receiver working medium side, the low-temperature receiver working medium side outlet that is provided with the low-temperature receiver working medium side inlet that is used to import low-temperature receiver working medium and is used to export low-temperature receiver working medium.
Further; The corrosion-resistant heat pipe flue gas waste heat recovery method of above-described coal-fired plant; And with the corrosion-resistant heat pipe flue gas waste heat recovery system of coal-fired plant that this method matches, can be applied to steam turbine heat regenerative system, DW system demineralized water system, heating system and air preheating system.
In the corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant; With the corrosion resistant heat exchange of heat pipe; Be installed between coal-burning power plant's (pulverized-coal fired boiler) booster fan and the desulfurizing tower; Reclaim the heat of condensation (latent heat) that part steam condenses and discharges in flue gas part of waste heat (sensible heat) and the flue gas, reclaim fume afterheat to greatest extent; Through the flue gas behind this coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery system, carry out the clean smoke moisture that desulfurization obtains again and reduce, the live load and the flue gas that have so just alleviated demister have also reduced the pollution to environment to the corrosion of chimney.The corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant has following characteristics:
⑴ improved the flue gas waste heat recovery efficiency of heat exchanger; Under the not limited situation of installing space, the corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant, the fume afterheat of recovery is more;
⑵ enlarged the range of application of flue gas waste heat recovery heat exchanger; The waste heat that reclaims not only can be used for the steam turbine heat regenerative system, can also be used for DW system demineralized water system, heating system and air preheating system etc.;
⑶ improved the security and the reliability of flue gas waste heat recovery heat exchanger; Cold fluid and hot fluid all flows outside pipe in the whole system, and separates fully, and single heat pipe works alone, and is independent of each other, quick detachable replacing; Even single heat pipe failure, not influence system works on, and the doping of cold fluid and hot fluid does not take place, not the security of operation of entail dangers to boiler;
⑷ can be reduced to flue gas below the water dew point, and the dust in the flue gas can stick to the enamel hot pipe surface, is that native system has certain dedusting effect;
⑸ can be reduced to 50-60 ℃ with flue-gas temperature, satisfies the requirement of wet desulfurizing process to flue-gas temperature, reduced to the required water yield of cooled flue gas, practiced thrift great amount of water resources.
The corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of each embodiment of the utility model is because this system comprises boiler, deduster, air-introduced machine, booster fan, corrosion resistant heat exchange of heat pipe, desulfurizing tower and the chimney that is connected through pipeline successively; This method comprises: in the flue system of coal-fired plant, set up the corrosion resistant heat exchange of heat pipe, the heat and the steam of flue system is recycled; And between the air-introduced machine and booster fan of flue system, draw the bypass flue, be connected between the desulfurizing tower and chimney of flue system; Adopt the corrosion resistant heat exchange of heat pipe, can make that cold fluid and hot fluid all flows in the whole flue system outside heat pipe, and separate fully, single heat pipe works alone, and is independent of each other, quick detachable replacing; Even single heat pipe failure does not influence flue system and works on, the doping of cold fluid and hot fluid does not take place, not the security of operation of entail dangers to boiler; Carry out the clean smoke moisture that desulfurization obtains again through the flue gas behind the corrosion resistant heat exchange of heat pipe and reduce, help alleviating the live load and the corrosion of flue gas of demister, and minimizing is to the pollution of environment chimney; Can be applied to steam turbine heat regenerative system, DW system demineralized water system, heating system and air preheating system, under the not limited situation of installing space, the fume afterheat amount of recovery is big; Thereby can overcome that energy saving is poor in the prior art, the feature of environmental protection is poor, cost is high, poor reliability and the big defective that takes up room, with realize good energy saving property, the feature of environmental protection is good, cost is low, good reliability, little and advantage applied range take up room.
Further feature of the utility model and advantage will be set forth in specification subsequently, and, partly from specification, become obvious, perhaps understand through implementing the utility model.The purpose of the utility model can realize through the structure that in the specification of being write, claims and accompanying drawing, is particularly pointed out and obtain with other advantages.
Through accompanying drawing and embodiment, the technical scheme of the utility model is done further detailed description below.
Description of drawings
Accompanying drawing is used to provide the further understanding to the utility model, and constitutes the part of specification, is used to explain the utility model with the embodiment of the utility model, does not constitute the restriction to the utility model.In the accompanying drawings:
Fig. 1 is the operation principle sketch map based on the fire coal boiler fume system of thermal power plant of low-pressure coal saver technology;
Fig. 2 a and Fig. 2 b are the structural representation of heat pipe;
Fig. 3 is the operation principle sketch map according to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant;
Fig. 4 is the partial structurtes sketch map according to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant;
Fig. 5 a is the cutaway view according to the main apparent direction of corrosion resistant heat exchange of heat pipe in the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant;
Fig. 5 b is the side view according to corrosion resistant heat exchange of heat pipe in the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant;
Fig. 6 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant in the operation principle sketch map of steam turbine heat regenerative system;
Fig. 7 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant in the operation principle sketch map of DW system demineralized water system;
Fig. 8 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant in the operation principle sketch map of heating system;
Fig. 9 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the utility model coal-fired plant in the operation principle sketch map of air preheating system.
In conjunction with accompanying drawing, Reference numeral is following among the utility model embodiment:
1-chimney, the 2-FGD baffle plate of going out, 3-1 absorption tower, 4-boiler, 5-deduster, 6-air-introduced machine, the 7-FGD baffle plate of entering; The 8-booster fan, 9-gas cooler, 10-oxidation fan, 11-low pressure (LP) cylinder, 12-generator, 13-JD6; 14-JD7,15-JD8,16-condensate pump, 17-condenser, 18-shell, 19-wick; The 20-steam channel, 21-baffle plate, 22-air preheater, 23-bypass flue, 24-fume side, 25-low-temperature receiver working medium side; The 26-desulfurizing tower, the outlet of 29-low-temperature receiver working medium side, 31-dividing plate, 32-corrosion resistant heat exchange of heat pipe, 33-low-temperature receiver working medium side inlet, 34-fume side inlet; The outlet of 35-fume side, 38-demister, 39-oxygen-eliminating device, 40-heat exchange station, 41-steam turbine, 42-pressure fan; The A-evaporator section, B-adiabatic section, C-condensation segment, liquid backflow direction in the D-wick.
The specific embodiment
Describe below in conjunction with the preferred embodiment of accompanying drawing, should be appreciated that preferred embodiment described herein only is used for explanation and explains the utility model, and be not used in qualification the utility model the utility model.
System embodiment
According to the utility model embodiment, shown in Fig. 2 a-Fig. 5 b, provide a kind of coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery system.
As shown in Figure 3, present embodiment comprises boiler 4, deduster 5, air-introduced machine 6, booster fan 8, corrosion resistant heat exchange of heat pipe 32, the desulfurizing tower 26 and chimney 1 that is connected through pipeline successively.
Here, in corrosion resistant heat exchange of heat pipe 32, heat pipe is in the shell 18 of sealing, to fill with working media and utilize the decalescence of medium and the high efficient heat exchanging element that heat exchange is carried out in heat release, and the structure of heat pipe can be referring to Fig. 2 a and Fig. 2 b.In Fig. 2 a and Fig. 2 b, heat pipe comprises columned shell 18, and near shell 18 and be axially disposed within the wick 19 of shell 18 inwalls; The inner passage of wick 19 is a steam channel, and liquid backflow direction is shown in the arrow D among Fig. 2 a in the wick 19.In the axial direction, from left to right, can heat pipe be divided into three sections, i.e. evaporator section A, adiabatic section B and condensation segment C.
Heat pipe is as the housing of a sealing, and shape is of all kinds, and its inner surface edge is overlapping the wick 19 (like capillary wick) of porous, and wick 19 is soaked full liquid phase working fluid, and its complementary space is then holding gas phase working medium.Outer thermal source is added heat at evaporator section A, makes the working medium evaporation of evaporator section A; The pressure reduction that causes thus drives steam and delivers to condensation segment C from evaporator section A, here steam condenses, and discharges the latent heat of vaporization; Condensed liquid phase working fluid leans on self gravitation and capillary pressure to get back to evaporator section A again, evaporates again.Like this, heat pipe continuously is sent to condensation segment C to the latent heat of vaporization from evaporator section, and does not dryout wick.As long as the working medium flow channel do not get clogged, and guarantee that liquid phase working fluid can get back to evaporator section, this process just will be proceeded down.
In in above-mentioned enforcement, the corrosion-resistant heat pipe flue gas waste heat recovery system of coal-fired plant also comprises bypass flue 23, first baffle plate 21, second baffle, the 3rd baffle plate, the 4th baffle plate and air preheater 22; Wherein, bypass flue 23 is drawn between self-induced-air machine 6 and the booster fan 8, is connected between desulfurizing tower 26 and the chimney 1; First baffle plate 21 is connected between desulfurizing tower 26 and the chimney 1; Second baffle is connected between deduster 5 and the blower fan 6; The 3rd baffle plate is arranged in the bypass flue 23; The 4th baffle plate is arranged between bypass flue 23 and the booster fan 8, and air preheater 22 is equipped with in boiler 4 and near the pipeline that is connected to deduster 5.
Shown in Fig. 4, Fig. 5 a-Fig. 5 b, above-mentioned corrosion resistant heat exchange of heat pipe 32 comprises the enamel hot pipe heat exchanger or is coated with the heat exchange of heat pipe of corrosion resistant coating.In the vertical direction, this corrosion resistant heat exchange of heat pipe comprises the upper and lower, and top is low-temperature receiver working medium side 25, and the bottom is a fume side 24, between fume side 24 and low-temperature receiver working medium side 25, is provided with dividing plate 31.
In fume side 24, be provided with the fume side outlet 35 that is used for the fume side inlet 34 that is connected with booster fan 8 and is used for being connected with desulfurizing tower 26.In low-temperature receiver working medium side 25, the low-temperature receiver working medium side outlet 29 that is provided with the low-temperature receiver working medium side inlet 33 that is used to import low-temperature receiver working medium and is used to export low-temperature receiver working medium.
In the above-described embodiments; The corrosion-resistant heat pipe flue gas waste heat recovery system of coal-fired plant; Mainly utilize enamel light pipe hot pipe technique; Fume afterheat and moisture that coal-powder boiler is discharged recycle, and this technology can be reduced to flue-gas temperature under the water dew point, can reclaim the heat of condensation of part steam in sensible heat and the recyclable flue gas of flue gas so to greatest extent.
Enamel is used for preventing the corrosion of heat exchanger acid dew, promptly outside the ordinary carbon steel pipe, is coated with one deck acid-proof enamel.Because enamel layer is very thin, therefore general thickness combines closely with carbon steel at 0.3mm, very little to the heat-transfer effect influence.The heat transfer coefficient of enamel pipe is compared with carbon steel pipe more than or equal to 48.3W/ (m2 ℃), and the relative reduced rate of heat transfer coefficient is less than 7.14%.For preventing dust stratification, in design, guarantee flue gas flow rate at 8-10m/s, the heat exchanging utensil has certain for the deashing ability; But because flue-gas temperature is reduced to below the water dew point, part water condenses in above dust stratification can stick to behind the enamel surface, can adopt the water spray mode to carry out deashing according to the ganoid characteristics of enamel.
In the above-described embodiments; Corrosion resistant heat exchange of heat pipe 32 belongs to the indirect type heat exchanger; Generally be installed in the flue zone between coal-fired plant boiler flue gas system booster fan 8 and the desulfurizing tower 26; Its fume side 24 is connected with the original system flue, and it is parallelly connected with the arbitrary therrmodynamic system pipeline in the power plant to be heated working medium side (being low-temperature receiver working medium side 25).Wherein, be heated working medium and can be arbitrary working media (like demineralized water, condensate, heating water, boiler air-supply etc.) that needs heating in the power plant.
During boiler operatiopn; The all or part of working medium that certain therrmodynamic system is shunted out in the power plant, the heat through corrosion-resistant heat exchanger 32 absorbs in the boiler exhaust gas improves the temperature of self with this; The working medium of rising temperature again with former therrmodynamic system pipeline in working medium converge; Heat in the boiler exhaust gas is sent in the middle of the therrmodynamic system, thereby has replaced the part heat that needs Steam Heating to provide in the therrmodynamic system, reduced power plant from steam consumption.Simultaneously, in the fume side 24 of boiler 4, the hot flue gas that comes out from boiler 4 back-end surfaces air preheaters 22; After deduster 5 dedustings, booster fan 8 boost, enter into corrosion resistant heat exchange of heat pipe 32, its heat is discharged to being heated working medium; Flue-gas temperature after the heat exchange reduces significantly; Satisfied the technological temperature requirement of desulphurization reaction needs, can directly get in the desulfurizing tower 26 and carry out the high efficiency desulfurization, and the low temperature clean flue gas after the desulfurization has been in the middle of chimney 1 is drained into atmosphere.
For example, certain 300MW Subcritical Units boiler is the 1025t/h pulverized-coal fired boiler, and boiler efficiency is 91.27%, and booster fan 8 back exhaust gas temperatures are 130 ℃, and exhaust gas volumn is 102.98 * 10
4Nm
3/ h.Between booster fan 8 and desulfurizing tower 26, install coal-burning power plant's (coal-powder boiler) corrosion resistant heat exchange of heat pipe 32 additional, flue-gas temperature is reduced to 80 ℃, the fume afterheat of recovery is used for heating heat regenerative system; Can make the 393t/h condensate from 45 ℃, be heated to 75 ℃, per hour reclaim the 49.58GJ heat; Practice thrift 1.844tce/h, reduce generating standard coal consumption 2.64gce/kwh, move calculating in 5000 hours per year; Can practice thrift mark coal 9220tce year, reduce CO
2Discharge capacity 24156t, SO2 discharge capacity 78t, NO
XDischarge capacity 68t.
And for example, certain 300MW Subcritical Units boiler is the 1025t/h pulverized-coal fired boiler, and boiler efficiency is 91.27%, and exhaust gas temperature is 130 ℃ behind the booster fan, and exhaust gas volumn is 102.98 * 10
4Nm
3/ h.Through calculating acid dew point is 81.21 ℃, and water dew point is 42 ℃.Between booster fan 8 and desulfurizing tower 26, install coal-burning power plant's (coal-powder boiler) corrosion resistant heat exchange of heat pipe 32 additional, flue-gas temperature is reduced to 42 ℃, can make the 695t/h condensate be heated to 95 ℃ from 45 ℃; Per hour reclaim the 146GJ heat; Practice thrift 5.43tce/h, reduce generating standard coal consumption 18.11gce/kWh, move calculating in 5000 hours per year; Can practice thrift mark coal 27167tce year, reduce CO
2Discharge capacity 71178t, SO
2Discharge capacity 231t, NO
XDischarge capacity 201t.
The corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description has following characteristics:
⑴ use corrosion resistant heat exchange of heat pipe 32 before desulfurizing tower 26, utilize hot pipe technique to reclaim the heat of condensation of part steam in the flue gas;
⑵ heating working medium diversification, recovery waste heat can be heated DW system demineralized water system, steam turbine heat regenerative system, heating system and air preheating system;
⑶ adopt enamel anticorrosion technology (being the enamel hot pipe heat exchanger), reclaims fume afterheat;
⑷ in the corrosion-resistant heat pipe flue gas waste heat recovery system of whole coal-fired plant, cold fluid and hot fluid all flows outside pipe, and separates fully, and single heat pipe works alone, and is independent of each other, quick detachable replacing; Even single heat pipe failure, not influence system works on, and the doping of cold fluid and hot fluid does not take place, not the security of operation of entail dangers to electricity generation system;
⑸ the corrosion-resistant heat pipe flue gas waste heat recovery system of coal-fired plant can be reduced to flue gas below the water dew point, reclaims the heat of condensation that part steam condenses and discharges in the flue gas;
⑹ can be reduced to flue gas below the water dew point, and the dust in the flue gas can stick to the enamel hot pipe surface, is that the corrosion-resistant heat pipe flue gas waste heat recovery system of this coal-fired plant has certain dedusting effect;
⑺ can be reduced to 50-60 ℃ with flue-gas temperature, satisfies the requirement of wet desulfurizing process to flue-gas temperature, reduced to the required water yield of cooled flue gas, practiced thrift great amount of water resources;
⑻ through the flue gas behind the above-mentioned coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery system, carries out the clean smoke moisture that desulfurization obtains again and reduces, and the live load and the flue gas that have so just alleviated demister have also reduced the pollution to environment to the corrosion of chimney.
Method embodiment
According to the utility model embodiment, provide the coal-fired plant that corrosion-resistant heat pipe flue gas waste heat recovery system matches of a kind of and above-mentioned coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery method, comprising:
In the flue system of coal-fired plant, set up corrosion resistant heat exchange of heat pipe 32, the heat and the steam of flue system is recycled;
Between the air-introduced machine 6 and booster fan 8 of flue system, draw bypass flue 23, be connected between the desulfurizing tower 26 and chimney 1 of flue system.
Wherein, above-mentioned corrosion resistant heat exchange of heat pipe 32 is equipped with between the booster fan 8 and desulfurizing tower 26 of flue system, and heat and steam in the flue gas between booster fan 8 and the desulfurizing tower 26 are recycled.Here, the structure of corrosion resistant heat exchange of heat pipe 32 and performance, can referring in the system embodiment to the related description of corrosion resistant heat exchange of heat pipe 32, repeat no more at this.
Corrosion-resistant heat pipe flue gas waste heat recovery method of the coal-fired plant of the foregoing description and the corrosion-resistant heat pipe flue gas waste heat recovery system of coal-fired plant that matches with this coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery method (can referring to system embodiment and the related description thereof shown in Fig. 2 a-Fig. 5 b) can be applied to steam turbine heat regenerative system, DW system demineralized water system, heating system and air preheating system.
Below in conjunction with Fig. 6-Fig. 9; The concrete application of the corrosion-resistant heat pipe flue gas waste heat recovery method of coal-fired plant that matches to the corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant and with above-mentioned coal-fired plant corrosion-resistant heat pipe flue gas waste heat recovery system is illustrated.
Fig. 6 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description in the operation principle sketch map of steam turbine heat regenerative system.In Fig. 6, save boiler 4 to booster fan 8 equipment before, this steam turbine heat regenerative system comprises booster fan 8, corrosion resistant heat exchange of heat pipe 32, demister 38, desulfurizing tower 26, chimney 1, multistage low oil (gas) filling device, low pressure (LP) cylinder 11 and generator 12; The fume side 24 and the desulfurizing tower 26 of booster fan 8, corrosion resistant heat exchange of heat pipe 32 connect through pipeline successively; After demister 38 cooperations are installed in the top of desulfurizing tower 26, be connected to chimney 1 through pipeline; Generator 12 is connected with low pressure (LP) cylinder 11, and low pressure (LP) cylinder 11 is connected with multistage low oil (gas) filling device; In multistage low oil (gas) filling device, add outlet and add between the inlet from certain level is low with next stage is low, the low-temperature receiver working medium side that introduction pipe is connected to corrosion resistant heat exchange of heat pipe 32 enters the mouth 33; From the low-temperature receiver working medium side of corrosion resistant heat exchange of heat pipe 32 outlet 29, the pipeline of drawing adds outlet and next stage low adding between the inlet introduces again from next stage is low.
In Fig. 6, will comprise the flue gas waste heat recovery system of corrosion resistant heat exchange of heat pipe 32, apply to the steam turbine heat regenerative system, can reclaim fume afterheat, and with reclaiming gained fume afterheat heat-setting water.
Fig. 7 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description in the operation principle sketch map of DW system demineralized water system.In Fig. 7, save boiler 4 to booster fan 8 equipment before, this DW system demineralized water system comprises booster fan 8, corrosion resistant heat exchange of heat pipe 32, desulfurizing tower 26, demister 38, chimney 1, oxygen-eliminating device 39, first valve, second valve and the 3rd valve; The fume side 24 and the desulfurizing tower 26 of booster fan 8, corrosion resistant heat exchange of heat pipe 32 connect through pipeline successively; After demister 38 cooperations are installed in the top of desulfurizing tower 26, be connected to chimney 1 through pipeline; Demineralized water is connected to oxygen-eliminating device 39 through the pipeline that second valve is housed, and from the pipeline of second valve away from oxygen-eliminating device 39, draws the low-temperature receiver working medium side inlet 33 of pipeline to the corrosion resistant heat exchange of heat pipe 32 that first valve is housed; The low-temperature receiver working medium side outlet 29 of corrosion resistant heat exchange of heat pipe 32 through the pipeline of the 3rd valve is housed, is connected between second valve and the oxygen-eliminating device 39.
In Fig. 7, will comprise the flue gas waste heat recovery system of corrosion resistant heat exchange of heat pipe 32, apply to DW system demineralized water system, as low-temperature receiver working medium, can reclaim fume afterheat with demineralized water, and with reclaiming gained fume afterheat heating demineralized water.
Fig. 8 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description in the operation principle sketch map of heating system.In Fig. 8; Save boiler 4 to booster fan 8 equipment before, this heating system comprises booster fan 8, corrosion resistant heat exchange of heat pipe 32, desulfurizing tower 26, demister 38, chimney 1, heat exchange station 40, first valve, second valve, the 3rd valve, steam turbine 41 and generator 12; The fume side 24 and the desulfurizing tower 26 of booster fan 8, corrosion resistant heat exchange of heat pipe 32 connect through pipeline successively; After demister 38 cooperations are installed in the top of desulfurizing tower 26, be connected to chimney 1 through pipeline; Generator 12, steam turbine 41 and heat exchange station 40 are connected successively; Heating water return enters the mouth 33 through the low-temperature receiver working medium side that the pipeline that first valve is housed is connected to corrosion resistant heat exchange of heat pipe 32, and is connected to heat exchange station 40 through the pipeline that second valve is housed; The low-temperature receiver working medium side outlet 29 of corrosion resistant heat exchange of heat pipe 32 through the pipeline of the 3rd valve is housed, is connected to the heating water output of heat exchange station 40.
In Fig. 8, will comprise the flue gas waste heat recovery system of corrosion resistant heat exchange of heat pipe 32, apply to heating system, as low-temperature receiver working medium, can reclaim fume afterheat with heating water return, and, use as heating water with reclaiming gained fume afterheat heating backwater.
Fig. 9 is for being applied to the corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description in the operation principle sketch map of air preheating system.In Fig. 9, save boiler 4 to booster fan 8 equipment before, this air preheating system comprises booster fan 8, corrosion resistant heat exchange of heat pipe 32, desulfurizing tower 26, demister 38, chimney 1, pressure fan 42, first valve and second valve; The fume side 24 and the desulfurizing tower 26 of booster fan 8, corrosion resistant heat exchange of heat pipe 32 connect through pipeline successively; After demister 38 cooperations are installed in the top of desulfurizing tower 26, be connected to chimney 1 through pipeline; Air is connected to the low-temperature receiver working medium side inlet 33 of corrosion resistant heat exchange of heat pipe 32 through the pipeline of first valve is housed; The low-temperature receiver working medium side outlet 29 of corrosion resistant heat exchange of heat pipe 32, the output combustion air through the pipeline of second valve is housed, is connected to pressure fan 42.
In Fig. 9, will comprise the flue gas waste heat recovery system of corrosion resistant heat exchange of heat pipe 32, apply to air preheating system; As low-temperature receiver working medium, can reclaim fume afterheat with air, and add hot-air with reclaiming the gained fume afterheat; Obtain combustion air, the feed blower fan uses.
The corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description has following beneficial effect:
⑴ good energy saving property: through corrosion-resistant heat pipe flue gas waste heat recovery system; The heat of condensation that part sensible heat and part steam condense and discharges in the recovery fume afterheat; Reclaim fume afterheat to greatest extent, flue-gas temperature is reduced to 50-60 ℃, satisfy the flue-gas temperature of wet desulfurizing process requirement; Significantly reduce desulfurization for reducing the water yield that flue-gas temperature consumes, practiced thrift great amount of water resources; Reclaim fume afterheat and can improve unit efficiency, reduce gross coal consumption rate, fuel savings is saved water resource, plays the good energy-conservation emission reduction effect;
⑵ the feature of environmental protection is good: in the corrosion-resistant heat pipe flue gas waste heat recovery system of above-mentioned coal-fired plant; Part steam can condense in the enamel hot pipe surface; Above dust can stick to; Play certain dedusting effect, the flue-gas temperature that gets into desulfurizing tower simultaneously satisfies the technological requirement of wet desulphurization, need not carry out spray cooling again.Therefore, reduced dustiness and water content in the clean flue gas, alleviated pollution environment.In addition, whole fume recovery system can reduce the consumption of the energy, has also just reduced CO
2, SO
2, NO
XDischarging, produce huge environmental benefit;
⑶ security and reliability improve: in the corrosion-resistant heat pipe flue gas waste heat recovery system of the coal-fired plant of the foregoing description; At first considered the security of equipment; Owing to be operated under the acid dew point even under water dew point; The measure of taking to plate enamel prevents that the acid of equipment from revealing corrosion, guarantees the heat exchange efficiency of equipment according to the characteristics of enamel take the to spray water way of deashing;
In addition, in the corrosion-resistant heat pipe flue gas waste heat recovery system of whole coal-fired plant, cold fluid and hot fluid all flows outside pipe and separates fully, and single heat pipe works alone, and is independent of each other, quick detachable replacing; Even single heat pipe failure can not influence whole heat exchanger and work on, the doping of cold fluid and hot fluid can not take place yet, the security of operation of entail dangers to boiler not is so strengthened the equipment reliability of operation greatly;
⑷ alleviate the demister burden: owing in desulfurizing tower, no longer flue gas is carried out the trickle cooling; Water capacity in the clean flue gas reduces; Change the working condition of demister in the sweetening process of knowing clearly, guarantee to remove fog effect, avoid the flue gas after being purified of guaranteeing of chimney rain can not pollute surrounding enviroment;
⑸ alleviate the corrosion of flue gas to chimney: the flue gas of low temperature and high relative humidity is the most serious to the corrosion of chimney, lacks and sprays water or do not spray water and can reduce the humidity of flue gas greatly, so also reduced the corrosion of chimney is guaranteed that system normally moves.
What should explain at last is: the above is merely the preferred embodiment of the utility model; Be not limited to the utility model; Although the utility model has been carried out detailed explanation with reference to previous embodiment; For a person skilled in the art, it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement.All within the spirit and principle of the utility model, any modification of being done, be equal to replacement, improvement etc., all should be included within the protection domain of the utility model.