CN110131742B

CN110131742B - Boiler smoke exhaust full-component treatment and resource recovery mode based on waste heat drive

Info

Publication number: CN110131742B
Application number: CN201910518926.2A
Authority: CN
Inventors: 李先庭; 赵健飞; 张茂勇; 石文星; 王宝龙; 陈炜; 刘世刚; 韩志刚; 张海鹏; 岑俊平; 熊烽; 陈军; 张刚刚; 王福东; 刘利刚
Original assignee: Beijing Qingda Tiangong Energy Technology Research Institute Co ltd; Tsinghua University
Current assignee: Beijing Qingda Tiangong Energy Technology Research Institute Co ltd; Tsinghua University
Priority date: 2019-06-16
Filing date: 2019-06-16
Publication date: 2024-04-26
Anticipated expiration: 2039-06-16
Also published as: CN110131742A

Abstract

A boiler smoke exhaust full-component treatment and recycling recovery mode based on waste heat drive belongs to the technical field of smoke treatment and circular economy. Aiming at the problems that the current boiler flue gas contains a large amount of water vapor and waste heat resources thereof, the tail feather carries more particle pollutants, particularly a large amount of penetrable particles and acid gas, a high-temperature dust remover is adopted to recycle smoke dust, meanwhile, a cascade condensation water film pollution removal mode is adopted to recycle condensed water, a large amount of sulfur dioxide and other acid gas in the flue gas tail feather, filterable particles, flocculable particles in penetrable particles, soluble particles and the like, the condensed water is carried and finally comprehensively recycled by a waste heat evaporation salt-separating crystallization device and the like, the condensed water is converted into building materials, industrial raw materials and the like, the recycled waste heat is used for driving the flue gas resource development process, and the recycled waste heat is used for heating, heating process water or combustion air and the like to realize the comprehensive resource utilization of hot, wet and dangerous wastes, and realize near zero-cost operation and even produce energy-saving and resource-saving economic benefits.

Description

Boiler smoke exhaust full-component treatment and resource recovery mode based on waste heat drive

Technical Field

The invention relates to a full-component treatment and recycling recovery mode of boiler exhaust gas based on waste heat driving, and belongs to the technical field of flue gas treatment and circular economy.

Background

The smoke discharged from boilers, various industrial kilns and the like which adopt fossil fuels such as coal, natural gas and the like to burn and burn heat contains a large amount of water vapor and a plurality of gaseous and solid pollutants, which become important pollutant sources influencing the atmospheric environment, and the prior art for treating haze, visual extinction and the like all belong to the focus environmental protection problems focused by public and policy departments, and enterprises are also focused on the technical feasibility, economic feasibility and secondary pollution problems in operation, namely the further treatment mode of waste liquid and solid waste and the cost problems thereof. However, the understanding and understanding of the cause of haze and the influence of smoke exhaust on the mechanism and degree of haze and the like are still to be deepened, so that the direction, mode and method of smoke exhaust treatment of a coal-fired boiler and the like are still to be deeply researched, and the matched solutions and systems, technical effects, investment and operation economy of industry enterprises, enterprise tolerance and the like are all to be deeply inspected. Several important problems and phenomena existing in the field of flue gas treatment of boilers or kilns at present include: the mechanism and the degree of the influence of the boiler smoke exhaust on haze are the first one; secondly, the smoke components after the ultra-low emission treatment of the boiler smoke and the influence mechanism on haze are adopted; thirdly, deeply treating the flue gas to achieve a technical approach of fundamentally eliminating or at least obviously slowing down the contribution degree of the flue gas to haze; fourthly, how the associated waste liquid and solid waste are solved, whether the possibility of recycling is provided and whether the technical approach is provided; fifthly, the key technology for realizing the technical approach, whether key equipment has feasibility, technical effect and influence on haze or white removal can be confirmed, and whether the technology, economic conditions, policy environment and the like for industrial popularization are provided.

Several important background of the invention are described below.

And (one) technical research background on haze causes.

To facilitate the discussion of the technological approaches to solve the problem, it is first necessary to review the general understanding and analysis of haze by people at present as follows. Haze weather is an atmospheric pollution state, haze is a general expression for exceeding the content of various suspended particles in the atmosphere, wherein the haze is an aerosol system formed by particles of dust, sulfuric acid (salt), nitric acid (salt) and the like in the air and causes visual impairment, and the particles are the culprit of adding to the pollution of the haze weather, and are carriers of toxic substances such as heavy metal, polycyclic aromatic hydrocarbon and the like. The haze particles are uniformly distributed, the size of the dust haze particles is smaller, the dust haze particles are from 0.001 micron to 10 microns, the average diameter is about 1-2 microns, and airborne particles cannot be seen by naked eyes. The chemical composition of the aerosol is very complex, and it contains various trace metals, inorganic oxides, sulfates, nitrates, oxygen-containing organic compounds, etc. The sulfate formed by the conversion of sulfur dioxide in the atmosphere is one of the main components of aerosol. Sulfur is the most important element in aerosols and its content reflects the global migration, transport and distribution of contaminants. The mechanism of nitrate and organic formation in aerosols has yet to be studied. Aerosols are derived from various elements of the industrial area (e.g., chlorine, tungsten, silver, manganese, cadmium, zinc, antimony, nickel, arsenic, chromium, etc.), and vary widely from area to area. Weather professionals indicate that haze weather formation is affected by both weather conditions and increased atmospheric pollutant emissions. The source of haze is various, such as automobile exhaust, industrial emission, building dust, garbage incineration, volcanic eruption and the like, and haze weather is usually formed by mixing various pollution sources.

Haze is harmful to the human body after inhalation into the respiratory tract of the human, such as long-term inhalation, and serious people can cause death. Particles above 10 microns are often retained in the nasal cavity and nasopharynx and throat from the perspective of harm to the human respiratory tract; the particles of 2 to 10 μm remain mostly in the upper respiratory tract, while the rate of retention of particles below 2 μm in the lung increases with decreasing particle size, and the rate of adhesion of particles below 0.1 μm in the bronchi increases with decreasing particle size. Because the diameter of the floating particles of fine powder particles in haze is generally below 0.01 micron, the floating particles can directly enter bronchi and even lungs through a respiratory system. Therefore, the most significant effect of haze is the respiratory system of people, and the diseases caused by haze are mainly focused on diseases such as respiratory diseases, cerebrovascular diseases, nasal inflammation and the like.

In summary, haze is a result of the combined action of acid gases such as sulfur dioxide, nitrogen oxides, and particulate matters, in which the particulate matters with smaller particle diameters, i.e., the particulate matters in the range of 0.001-0.1 μm, are more likely to form a more stable aerosol state, which is one of the main factors of haze formation; meanwhile, the threat to human health is generally considered to be more serious, and the method is one of main efforts for haze removal.

And (II) new discovery and research progress of the influence of boiler smoke on haze.

In recent years, environmental protection, emission reduction and efficiency improvement with multiple rounds of universality are implemented for pollution enterprises such as coal-fired power plants and the like, and great effects are achieved, particularly, ultra-low emission indexes, namely smoke dust not higher than 5mg/Nm, sulfur dioxide not higher than 35mg/Nm and nitrogen oxides not higher than 50mg/Nm, are commonly realized in thermal power plants, but air pollution is not fundamentally solved, and heavy haze pollution weather still occurs. At present, the national standard (GB 16157-1996) for measuring the existing particulate matters in China only measures the particles with the particle size of more than 0.45 microns (PM 0.45). Then whether particulate matter less than PM0.45 is another major contributor to haze, white flue gas produced by wet desulfurization means contains a significant amount of dissolved particles (TDS-Total Dissolved Solids), meaning the sum of solid particulate matter dissolved in the liquid, typically between a fraction of a nanometer to a few hundred nanometers in size (most smaller than the current monitored dimensions PM 0.45). The flue gas at the outlet of the wet desulfurization device contains a large amount of supersaturated vapor, so that the phenomenon of 'white pinnate fog tailing' appears in a chimney, and the actual measurement proves that the flue gas contains a large amount of vapor, also contains a large amount of dissolved particles and harmful heavy metals, floats in the air after being discharged from the chimney, and is suspended in the atmosphere for a long time as moisture is evaporated. Typically, PM2.5 particles can be suspended in the atmosphere for 100 hours, PM1 particles can be suspended in the atmosphere for 1000 hours, while such smaller particles (below 0.45 PM) are suspended for a longer period of time and are more difficult to settle, and as meteorological and humidity conditions are suitable for rapid agglomeration, aerosol (Aerosol) is formed, causing haze contamination.

The 1# machine set of Tianjin national electric and jin energy thermoelectric limited company is finely measured from 15 days of 2017, 8 months to 30 days of 8 months. The environment-friendly facilities such as denitration, dust removal and desulfurization of the unit and the main engineering are put into operation in 8 months and 12 days in 2009. The environmental protection detection of the unit reaches the standard (the emission of the particulate matters is less than 10mg/Nm 3). Three sets of data are obtained by testing through a distilled water washing method, so that the dissolved particles are reasonably presumed to be an important cause of the long-term unhealed haze, and the actual measurement results are analyzed as follows.

(1) In the test, after limestone-gypsum wet desulfurization, 87 mg/standard cubic meter of dissolved particles in the flue gas are discharged; after passing through the wet electrostatic precipitator, 76 mg/standard cubic meter still remains. These two data, the existing national standard for clean emissions with particulate emissions less than 10 mg/standard cubic meter is Gao Yuchao. This illustrates: 1) A large amount of dissolved particles are generated and discharged after wet desulfurization; 2) The wet electric dust remover has very little effect of removing the dissolved particles and cannot be used as an equipment option for removing the dissolved particles; 3) The dissolved particles are extremely fine and are missed, the vision of people is escaped, the particles are free from going, and the particles are discharged into the atmosphere in a legal way.

(2) And (5) calculating the discharge amount of the dissolved particles and evaluating pollution. The measured amount of the dissolved particles discharged by the unit (capacity 330 MW) can be calculated to be about 131 kg/h; the discharge amount of the dissolved particles discharged from the boiler of the capacity 1000MW unit is 397 kg/hr. The concentration of the haze 'explosion meter' is 500 mug/m < 3 >, and the amount of dissolved particles discharged by the power plant per hour can enable the atmospheric space of about 2km (length) x2km (width) x200m (height) to reach the 'explosion meter' concentration under the condition of poor diffusion.

(3) The capacity of the coal-fired total assembly machine for power generation in China is about 9.0625 hundred million kilowatts, and 99 percent of the total assembly machine is additionally provided with a wet desulfurization device. As calculated from the above data, only one dissolved particle emission of desulfurization in coal-fired power plants is up to about 260 ten thousand tons/year. Users of coking, steelmaking, chemical, cement, industrial boilers, etc. have not been included herein. In addition, "splash-evaporative" cooling is also a large household of emissions of dissolved particulates. If these are all included, it is estimated that dissolved particle (TDS) emissions may approach or be higher than 1000 ten thousand tons/year. The total amount of contaminants even exceeds the total amount of dust emissions we know, plus a longer suspension time. It can thus be derived that: dissolving particles is yet another important cause of haze.

(4) And (5) analyzing the pH value of the water vapor in the flue gas. The pH value is usually measured to be 2-3, and acid rain can be formed when the steam enters the atmosphere in rainy days (the annual emission of the strong acid steam is up to 9 hundred million tons). This is because catalytic denitrification (SCR) converts more SO2 in the flue gas into SO3, and SO3 is very difficult to remove by current wet desulfurization; in addition, the ammonia escape phenomenon in denitration can make the vapor in the smoke exhaust have strong acidity.

In summary, the flue gas of the coal-fired boiler flue gas subjected to wet desulfurization contains a large amount of dissolved particles with smaller particle size, the actual content of the dissolved particles reaches 70-100 mg/Nm < 2 > in the condition of realizing 'ultra-low' emission, which is equivalent to or even larger than the sum of the contents of three types of detection pollutants which realize 'ultra-low' emission at present, so that the actual ultra-low emission is not really ultra-low, but is not considered enough by people because the actual ultra-low emission is not brought into a monitoring range at present, but is difficult to capture with escaping acid gas by a wet electric dust collector behind a desulfurizing tower, so that the dissolved particles are discharged into the atmosphere in a large amount, and become one of main factors influencing the atmospheric environment and haze formation in the current flue gas.

And (III) technical analysis on the concept, essence and value of flue gas whitening.

At present, more than ten provinces and cities including Shanghai, tianjin, hebei and the like come out of the platform and are related to local standards of whitening, wherein in south areas such as Shanghai and the like, the smoke temperature is often required to be increased to realize the wider high-altitude diffusion of smoke and dust discharge so as to reduce dust pollution to the ground and adjacent air and realize visual whitening. However, unlike in southern areas, the northern whitening standard does not require complete elimination of white visual pollution in winter, for example, policy departments such as Tianjin, hebei, etc. require the goal and essence of whitening: the condensation heat exchange can effectively reduce the water vapor content, effectively reduce haze pollutants such as soluble salt and the like, and lighten the visual pollution of 'white smoke'.

The key problem of whitening, essence and environmental protection value are that firstly, various pollutants such as soluble salt, heavy metal, acid gas and the like are greatly reduced to influence haze and the key factors which harm human health, secondly, the visual pollution of 'white fog' is lightened and eliminated, and if the visual pollution is mainly solved, but various pollutants contained in the smoke cannot be effectively treated, the 'whitening' is greatly increased in electric energy, reheat steam heat energy and the like, the energy consumption and the corresponding pollution emission are excessively increased, and the practical significance is not realized, and the 'whitening' behavior of the last inversion and the sergeant fish is carefully demonstrated or even cancelled.

(IV) review of the technical development of the leading patents.

(1) The latest development of flue gas waste heat deep recovery and whitening technology.

The university of Qinghua and other scientific research institutions and enterprises are combined to develop and popularize various flue gas waste heat recovery patent technologies, wherein 'the serial patent technical achievements based on the steam heat-carrying circulation type flue gas waste heat recovery heat supply technology' comprise 'a direct recovery method and device (2017104371042) of the flue gas heat and humidity of a boiler based on the steam heat-carrying circulation', 'a total heat recovery and flue gas whitening device (2017206805342) of the flue gas of a flue gas tower-integrated boiler', and the like, are successfully verified through demonstration engineering and are listed in the category of the 8 th energy-saving technology in 2018 of Shandong province, the direct heat exchange mode is adopted instead of a heat pump, the flue gas temperature can be reduced to about 30 ℃, and the water vapor content in the flue gas is reduced by more than 70% -80% while a large amount of the latent heat of steam and water resources are recovered, so that the obvious whitening is realized; meanwhile, filterable particles (flue gas on-line monitoring parameters) can be reduced by 30% -50%, more importantly, soluble acid gases such as sulfur dioxide, hydrogen chloride and the like can be basically reduced to 0, gypsum, soluble salts, heavy metals and the like can be reduced by more than 60% -80%, and a plurality of key factors in haze causes are obviously eliminated.

(2) The feasibility and technical approach of recycling the water vapor and pollutant components contained in the flue gas.

The technical approaches which are already mature at present include: the dust can be recycled through a dust remover to be used as building materials and the like; sulfur dioxide is removed by a desulfurizing tower and converted into gypsum.

The flue gas pollutant components after realizing ultra-low emission can be transferred into the circulating water by a condensation or spray washing method, but the overflow effluent water in the flue gas pollutant components needs to find a technical mode of resource utilization. While the current industrial high-salt wastewater and dangerous waste salt seriously pollute the environment, the conventional treatment methods at present, such as pretreatment, membrane treatment, MVR evaporation or multi-effect evaporation, etc., have the following technical problems: the initial investment is huge, the operation energy consumption and the operation maintenance cost are too high, so that most enterprises are difficult to bear the cost of comprehensively recycling sewage and dangerous waste salt.

The technical mode of waste heat driven sewage evaporation crystallization and recycling is creatively adopted by the professor team of Qinghua university Li Xianting, waste heat of industrial enterprises such as thermal power plants is adopted to replace conventional MVR evaporation power consumption, multi-effect evaporation steam consumption and other high-grade energy sources as driving heat sources, evaporation salt separation of high-concentration sewage is realized, and finally zero sewage discharge is realized through waste salt recycling, wherein main patent achievements comprise: a sewage zero discharge and resource recovery system (2018214627233) based on the driving of the waste heat of a thermal power plant, a desulfurization waste water recovery and crystallization salt purification system (2018214381695) adopting the driving of the waste heat, and the like.

The technical mode can greatly reduce initial investment, can also greatly reduce energy running cost, and can simultaneously save the original process system including water resource tax, pollution discharge cost, process operation maintenance cost and the like.

The thermal sewage zero discharge and resource recovery serialization patent technology based on waste heat drive provides a solid technical foundation for the full-component treatment of the flue gas and the resource utilization of pollutants thereof.

(3) Accurate measurement of smoke components and influence of the smoke components on haze.

The expert team of Dan Ai army, north gigahertz Chen intelligent energy technology Co., ltd Zhao Jianfei in Beijing city, through adopting the new-type high-precision nano-grade particle detection instrument and measurement method, theoretical research and engineering actual measurement are carried out on the measurement method and component characteristics of polymorphic particles in wet desulfurization flue gas, and the distribution situation of 11 main ions in the flue gas is shown as follows: the ions containing sulfate radical and sulfite account for more than 82 percent of the total mass, and are the main source of PM 2.5; nitrite content is relatively high, so that it is necessary to bring the escapable particles such as soluble particles into the monitoring and treating range.

(4) The technical development of high-temperature dust collectors.

The filter material and the bag type dust collector of basalt and other materials are successfully developed, and the static ash-removing bag type dust collector technology is developed and successfully popularized, so that the efficient, stable and reliable dust removal can be realized in medium-high temperature flue gas, namely, about 300-350 ℃, and the catalytic effect of a subsequent medium-high Wen Tuoxiao catalyst can be remarkably improved, thereby improving the denitration performance index, avoiding the poisoning of the catalyst, and effectively reducing the investment and the operation cost.

(5) The development of a high-efficiency low-cost dividing wall type heat exchange technology.

The successful development of the extrusion molding aluminum fin type heat exchanger adopting graphene for surface corrosion prevention can replace the existing heat exchanger adopting special materials such as expensive metal or fluoroplastic, has strong acid and alkali corrosion resistance, low material consumption, long service life, small maintenance amount and the like, and is suitable for being adopted under the working conditions of strong corrosiveness and even deep dew of boiler flue gas.

In summary, the current situation relates to the advanced technology of flue gas waste heat recovery, the deep analysis of flue gas components and the research of the influence of the advanced technology on haze, the flue gas waste heat recovery technology, the zero sewage discharge based on waste heat driving, the recycling recovery and other technical research and popularization achievements, and important technical conditions are provided for the development of the full-component treatment of the haze prevention and the recycling recovery technology of pollutants.

Disclosure of Invention

Aiming at the problems that the full component analysis of the boiler exhaust gas shows that a large amount of soluble salt escapes and the like obviously influence the formation of haze and the pollution of air, the invention adopts a grading treatment system technology and a plurality of key and novel technical achievements to realize the technological processes of high-temperature efficient dust removal, efficient denitration, waste heat driven cascade full component treatment, waste heat driven zero discharge of sewage, recycling recovery thereof and the like, and effectively reduces the current escapable pollutants such as water vapor, soluble salt, acid gas and the like in the exhaust gas, thereby realizing the fundamental anti-haze and whitening treatment of the boiler exhaust gas, recycling the removed pollutants, realizing the combination of environmental protection benefit and circular economy, and converting the environmental protection treatment of the exhaust gas into sustainable economic development of smoke resources.

The haze removal mechanism, the smoke resource development principle and the technical path are briefly described as follows. Firstly, the flue gas is firstly dedusted by adopting a high-temperature deduster, and then the flue gas is sent into a medium-high-temperature denitration device, so that the denitration efficiency can be improved, the NOx content can be further reduced, the catalyst poisoning can be avoided, the excessive ammonia spraying amplitude can be reduced, and the ammonia escape amount can be reduced. Secondly, the method is beneficial to reducing the poisoning of the desulfurizing agent in the desulfurizing tower and ensuring the running stability of a desulfurizing system and the stability of a desulfurizing effect. Thirdly, the wet electric dust collector which does not have substantial effect on deep removal of dissolved particles and acid gas is not adopted in the deep dust falling process, but a brand new step condensation water film decontamination module is adopted instead, and the adopted mechanism comprises: the wet desulfurization outlet flue gas is in a supersaturated aerosol state with the properties of fog and haze, wherein nano-sized particles (0.001-0.1 micron) and part of acid gas form a mixture with a sedimentation scale through collision, condensation and the like with fog drops and particles with larger scale, and the mixture is removed by removing the part of liquid-solid mixture; through condensation heat exchange, various particulate matters and acid gases in the flue gas are carried and removed along with condensation water; the water bath principle is that particles, particularly dissolved particles and acid gas in the flue gas are washed by the spraying action of circulating water; the water film dedusting principle is that a large amount of wall liquid film is used for absorbing and absorbing particles, particularly dissolved particles and acid gas in the flue gas by creating a large amount of action mechanisms such as inertial collision, brownian motion, direct absorption and the like of direct contact, baffling flushing and the like of the wall liquid film and the flue gas; the hot pressing and high-altitude diffusion principles of the chimney are that the smoke temperature and the water vapor content thereof are greatly reduced, the smoke is heated and warmed up again, the floating force and the thermal pressure difference are improved, the air flow floating of the chimney mouth and the purification and emission effects of high-altitude diffusion are improved, and the like. Fourth, the resource development of the flue gas pollutants, except for the conventional dust remover, is realized by recovering water resources and waste heat resources in a waste heat driving mode, and converting solid waste into industrial raw materials, building materials and the like through flocculation precipitation, salt separation crystallization and the like for resource utilization.

The specific description of the invention is as follows: the utility model provides a boiler discharges fume total composition and controls and resource recovery mode based on waste heat drive, adopt by the haze removal system of a set of flue gas total composition control and resource recovery utilization's technological process constitution, resource recovery technological system in order to reduce the vapor in the flue gas by a wide margin, but escape particulate matter and filterable particulate matter including the soluble salt of nanoscale scale, acid gas including sulfur dioxide and hydrogen chloride, the haze removal technological process and the resource conversion and recovery technological process of comprehensive elimination or effective suppression atmospheric haze influencing factor that leads to and realizing waste heat recovery drive that discharges fume, its characterized in that: the boiler smoke exhaust full-component treatment and recycling recovery mode and the system process flow thereof comprise a high-temperature or medium-low-temperature dust removal process, a cascade condensation waste heat recovery and water film decontamination process, a medium-temperature section smoke heat recovery process, a condensate recycling process for desulfurization water supplementing and desalted water preparing process, a desulfurization wastewater zero emission and recycling recovery process, wherein the specific process flow comprises the following steps:

i. Firstly, a high-temperature dust remover 2 is arranged at a flue gas outlet of a medium-temperature flue gas heating surface 1a with the outlet flue gas temperature between 300 and 350 ℃ in a tail heating surface of a boiler 1, and flue gas subjected to high-temperature dust removal is sent into a denitration device 3, so that the technical condition of generating denitration catalyst poisoning is eliminated, high-efficiency and low-cost stability of medium-high Wen Tuoxiao is realized, and the high-temperature dust remover 2 is used for recovering dust resources used as building materials;

secondly, the primary purified flue gas after high-temperature dust removal and medium-high temperature denitration enters an existing medium-low temperature flue gas heating surface 1b of a boiler and carries out high-efficiency stable heat exchange under the technical condition of avoiding dust scaling, and then enters a medium-temperature section flue gas heat recoverer 6 to recover the sensible heat of the primary purified flue gas and serve as a heating source of a waste heat air preheater 4 and a waste heat evaporation crystallizer 8b, wherein the waste heat air preheater 4 carries out second-stage sensible heat preheating on boiler combustion-supporting air;

Thirdly, the flue gas continuously enters a desulfurization tower 7 for desulfurization, the desulfurization wastewater is sent to a desulfurization wastewater waste heat evaporation salt separation crystallization module 8, and water resources, industrial raw material resources including industrial sodium chloride and building material raw material resources including gypsum and heavy metal stabilizing compounds are recovered;

Fourthly, the desulfurized flue gas is sent into a flue gas inlet of the cascade condensation water film decontamination module 9 for deep purification, and sequentially passes through a flue gas inlet section 9k and a multistage washing condensation water film decontamination device from bottom to top, and is sent out to the atmosphere through a flue gas outlet at the top of the cascade condensation water film decontamination module 9 for diffusion and discharge, wherein water vapor in the flue gas, escapable particles including soluble salt with nanoscale dimensions, filterable particles and acid gas including sulfur dioxide and hydrogen chloride are absorbed and adsorbed by spraying circulating water and condensed water and are intercepted, and the water is settled in a water tank 9l at the bottom of the tower, and redundant condensed water in the water tank 9l at the bottom of the tower is used as circulating water of a desulfurizing tower and process water supplementing in a factory including a desalted water preparation process;

Fifthly, the high-temperature residual hot water in the tower bottom water tank 9l is sent to the residual heat user heater 10 for preheating heating backwater and process backwater, and part of the cooled residual heat water is sent to the total heat air preheater 11 for carrying out first-stage total heat preheating on boiler combustion-supporting air, so that cascade recycling of flue gas residual heat resources, particularly latent heat residual heat, is realized;

Sixthly, the rest part of the cooled waste heat water of the waste heat user heater 10 is used as a medium-low temperature cold source, is sprayed by the circulating spraying device 9f and then drives the lower washing heat exchanger 9g to perform condensation heat exchange and wash smoke, the waste heat water effluent of the all-hot air preheater 11 is used as a low temperature cold source, is sprayed by the washing spraying device 9c and then drives the upper washing heat exchanger 9d to perform deeper condensation heat exchange and wash smoke, and meanwhile, part of the hot user backwater H0 is used as a medium-low temperature cold source and is sent into the dividing wall condenser 9H to perform dividing wall condensation heat exchange on the smoke, and the smoke condensate forms a water film on the outer wall surface of the dividing wall condenser 9H to purify the smoke through absorption and adsorption;

Seventhly, the secondary steam Q on the sewage side of the waste heat evaporation crystallizer 8b is sent to the secondary steam heat recoverer 8c, and then is released heat and condensed to recover water resources of condensation water QN, and the secondary waste heat water outlet J2 on the heated side is used as a reheating heat source to be sent to the white heat elimination exchanger 9a to achieve reheating and heating of low-temperature low-humidity purified flue gas, and high-altitude diffusion and emission after floating lift force is improved.

The boiler smoke exhaust full-component treatment and recycling recovery system based on waste heat driving comprises a high-temperature or medium-low-temperature dust removal module, a cascade condensation waste heat recovery and water film decontamination module, a medium-temperature section smoke heat recovery module, a condensate recycling module for desulfurization water supplementing and desalted water making, a desulfurization wastewater zero emission and recycling recovery module, wherein the specific process system comprises the following steps:

i. The flue gas inlet of the high-temperature dust remover 2 is connected with the flue gas outlet of a medium-temperature flue gas heating surface 1a with the outlet flue gas temperature of 300-350 ℃ in the tail heating surface of the boiler 1, the flue gas outlet of the high-temperature dust remover 2 is connected with the flue gas inlet of the denitration device 3, the flue gas outlet of the denitration device 3 is connected with the flue gas inlet of a medium-low-temperature flue gas heating surface 1b, and the bottom of the high-temperature dust remover 2 is provided with a discharge port for discharging dust D;

The outlet flue gas of the medium-low temperature flue gas heating surface 1b is connected with the flue gas inlet of the medium-temperature section flue gas heat recoverer 6 through the flue gas outlet of the boiler body air preheater, the flue gas outlet of the medium-temperature section flue gas heat recoverer 6 is communicated with the flue gas inlet of the desulfurizing tower 7, the heated water outlet of the medium-temperature section flue gas heat recoverer 6 is respectively connected with the high Wen Cejin water gap of the waste heat air preheater 4 and the high Wen Cejin water gap of the waste heat evaporation crystallizer 8b, the heated water inlet of the medium-temperature section flue gas heat recoverer 6 is respectively connected with the high-temperature side water outlet of the waste heat air preheater 4 and the high-temperature side water outlet of the waste heat evaporation crystallizer 8b, the outlet of the combustion air outlet (A2) of the waste heat air preheater 4 is connected with the combustion air inlet of the boiler body air preheater, and the inlet of the combustion air inlet (A1) of the waste heat air preheater 4 is connected with the combustion air outlet of the full heat air preheater 11;

The method comprises the steps that the outlet water S of a desulfurization tower 7 enters a buffer tank 7a, a water outlet pipe of desulfurization circulating backwater SH at a circulating water outlet of the buffer tank 7a is communicated with a water inlet pipe of a desulfurization water supplementing B2 and a water inlet pipe of a desulfurization circulating water supply SG, the buffer tank 7a is further provided with a water outlet of gypsum SS and a water outlet of desulfurization wastewater P1, wherein the water outlet of the desulfurization wastewater P1 is communicated with a water inlet of a wastewater pretreatment tank 8a of a desulfurization wastewater waste heat evaporation salt separating crystallization module 8, the wastewater pretreatment tank 8a is further provided with a chemical adding inlet of a reagent G, a water outlet of desulfurization solid waste SP containing gypsum and heavy metal stabilizing compounds and an outlet of desulfurization wastewater pretreatment water P2, the outlet of the desulfurization wastewater pretreatment water P2 is connected with a water inlet of a waste heat evaporation crystallizer 8B, the outlet of industrial grade sodium chloride NC and an outlet of sewage side secondary steam Q are further provided, the outlet of the secondary steam heat recoverer 8c is further provided with a water outlet of a secondary steam heat recoverer 8c and a secondary steam heat recoverer 9 c, and the water outlet of the secondary steam recoverer 8c is further provided with a water inlet of a secondary heat recoverer 9;

The flue gas outlet of the desulfurizing tower 7 is connected with the flue gas inlet of the cascade condensation water film decontamination module 9, and the internal scale of the cascade condensation water film decontamination module 9 sequentially comprises the following condensation washing purification process structures or devices from bottom to top: the flue gas inlet section 9k and the multi-stage washing condensation water film decontamination device are connected with the external atmosphere through a flue gas outlet at the top of the cascade condensation water film decontamination module 9, and a tower bottom pool 9l is arranged at the lower part of the flue gas inlet section 9 k;

The high-temperature waste heat water outlet of the tower bottom water tank 9l is respectively communicated with a water outlet pipe of the water supplementing B, an inlet of the high-temperature side water inlet R1 of the waste heat user heater 10 and a circulating water inlet of the cooling tower after passing through a circulating water pump, the water outlet pipe of the water supplementing B is communicated with a water supplementing pipe of the desulfurization water supplementing B2 and a water supplementing pipe of the process water supplementing B1 including desalted water in a factory, the outlet of the high-temperature side water outlet R2 of the waste heat user heater 10 is respectively communicated with a middle-low temperature cold source through a water inlet of the circulating spray device 9f and a water inlet of the total heat air preheater 11, the low-temperature side inlet of the waste heat user heater 10 is respectively communicated with a water return pipe of the hot user backwater H0 and a water inlet of the partition wall condenser 9H, and the outlet of the low-temperature side water outlet H2 of the waste heat user heater 10 is respectively communicated with an outlet of the partition wall condenser 9H and a water outlet pipe of the preheated hot user backwater H3;

And a water outlet of a water pool at the bottom of the total-heat air preheater 11 is communicated with a water inlet of the washing spray device 9c, an air inlet of the total-heat air preheater 11 is communicated with a boiler air inlet A0, and an air outlet of the total-heat air preheater 11 is communicated with an inlet of a combustion-supporting air inlet A1 of the waste heat air preheater 4.

The multistage washing condensation water film decontamination device inside the cascade condensation water film decontamination module 9 sequentially comprises the following condensation washing purification process and device from bottom to top: the washing condensation rain area 9j, the unidirectional rectifier 9i, the partition wall condenser 9h, the lower washing heat exchanger 9g, the circulating spray device 9f, the washing demister 9e, the upper washing heat exchanger 9d, the washing spray device 9c, the demister 9b and the white heat elimination heat exchanger 9a, wherein the upper air outlet side of the white heat elimination heat exchanger 9a is communicated with the top smoke outlet of the step condensation water film decontamination module 9.

The high-temperature dust remover 2 adopts a bag type dust remover structure made of basalt filtering materials.

The full-heat air preheater 11 adopts a direct contact type spray heat exchange tower structure with the function of heating and humidifying the boiler combustion air.

The medium-temperature flue gas heating surface 1a, the medium-low-temperature flue gas heating surface 1b, the waste heat air preheater 4, the medium-temperature section flue gas heat recoverer 6, the white heat elimination heat exchanger 9a and the partition wall condenser 9h adopt an extrusion molding aluminum fin heat exchange tube structure coated with graphene materials.

The lower washing heat exchanger 9g and the upper washing heat exchanger 9d are made of strong acid and alkali corrosion resistant and fouling and blocking resistant condensation heat exchange materials.

The inlet washing solution Na of the washing spray device 9c adopts sodium hydroxide dilute solution with the pH value of 7-10.

Aiming at the problems that the tail of the boiler flue gas carries more particulate pollutants, particularly a large amount of penetrable particulate matters (PM 0.3 and below) and acid gas, and belongs to one of the main causes of haze and pollutes the environment adjacent to the ground, the invention adopts a high-temperature dust remover to improve the efficiency of a denitration device and eliminate toxic sources, adopts a cascade condensation water film decontamination module to greatly reduce acid gases such as water vapor, sulfur dioxide, hydrogen chloride and the like, filterable Particulate Matters (FPM), flocculable particulate matters (CPM) and soluble particulate matters (DPM) in penetrable particulate matters (EPM), and clean smoke discharge high-altitude diffusion emission, thereby fundamentally reducing or basically eliminating the substantial adverse effects of boiler smoke discharge on haze formation and surrounding air environment.

Meanwhile, waste heat recovery is used as an important driving force in the step haze removal process, on one hand, the flue gas releases heat to generate a large amount of condensed water to remove water vapor, and meanwhile, more acid gas, escapable particles, filterable particles and the like are absorbed or adsorbed; on the other hand, a part of higher-grade waste heat is adopted to reheat the outlet flue gas so as to realize visual whitening, improve the diffusion effect of the outlet flue gas in the atmosphere and effectively reduce the pollutant concentration of an adjacent airspace; meanwhile, the condensed water washes the lower overflow wall surface to remove adhered pollutants, and further absorbs or adsorbs more pollutants through a water film; and the temperature of the circulating water falling into the water tank at the bottom of the tower is increased, heat of the circulating water can be transferred into backwater of a downstream heat user through a heat exchanger to realize waste heat utilization, the cooled water is conveyed to a spraying device by a water pump to continuously and deeply recover flue gas condensate and absorb or adsorb pollutants, and the redundant condensate is discharged and reused as desulfurization water supplement and the like.

Furthermore, waste heat recovery is used as a main driving force for zero discharge of sewage external drainage containing smoke pollutants and a recycling recovery process thereof, so that the total water resources are recovered, and meanwhile, the contents are subjected to grading treatment, wherein heavy metal ions are removed through dosing and precipitation and converted into a stable compound state, and the heavy metal ions can be used as building material raw materials; phosphate is converted into gypsum through a waste heat evaporation salt separation crystallization process, and chloride is converted into industrial raw materials such as industrial sodium chloride, so that the conversion of pollutants into resources is realized.

Finally, waste heat resources of different grades of flue gas are extracted in a grading mode and are respectively used for the driving process, and are used for heating combustion air of a boiler to save coal, heating a heating heat supply network backwater or process water to save steam and the like, so that more remarkable energy-saving benefits are generated, and the energy conservation itself correspondingly reduces the fuel consumption and the pollution emission thereof.

The energy-saving benefit and the resource recovery benefit are remarkable, so that multiple effects of flue gas pollution treatment, resource utilization, energy-saving benefit and the like are realized, and an integrated treatment process of energy conservation and emission reduction is realized, so that environmental protection investment and operation with economic benefit are realized, and the method has remarkable technical and economic advantages in the deep energy-saving recovery and emission reduction treatment field of boiler exhaust gas.

On the other hand, when the system has a larger heating load demand in winter, the water vapor condensation waste heat can be largely converted into heat recovery heating; in the non-heating period, except that part of the waste heat can be used for preheating the inlet air of the boiler to save fuel, the waste heat utilization benefit can be realized only by searching for downstream heat users such as process water heating, or else, when the waste heat cannot be utilized more, only the part of the waste heat can be dissipated into the atmosphere by additionally arranging a cooling tower, and the like, but at the moment, part of water supplementing, water pump, fan power consumption, and the like still need to be consumed, so that the purposes of deeply reducing the emission of flue gas pollution and visual whitening in summer are realized in the step condensation water film decontamination process.

Drawings

Fig. 1 is a schematic diagram of the system of the present invention.

The component numbers and names in fig. 1 are as follows.

The boiler 1, the medium-temperature flue gas heating surface 1a, the medium-low temperature flue gas heating surface 1B, the high-temperature dust remover 2, the conventional medium-low temperature dust remover 2D, the denitration device 3, the waste heat air preheater 4, the induced draft fan 5, the medium-temperature section flue gas heat recoverer 6, the desulfurizing tower 7, the buffer tank 7a, the desulfurizing waste water waste heat evaporation salt separating crystallization module 8, the waste water pretreatment tank 8a, the waste heat evaporation crystallizer 8B, the secondary steam heat recoverer 8c, the step condensation water film decontamination module 9, the white heat removal heat exchanger 9a, the demister 9B, the washing spray device 9c, the upper washing heat exchanger 9D, the washing demister 9e, the circulating spray device 9f, the lower washing heat exchanger 9g, the partition wall condenser 9H, the unidirectional rectifier 9i, the washing condensation rain zone 9J, the flue gas inlet section 9k, the bottom water tank 9l, the waste heat user heater 10, the total heat air preheater 11 the boiler air intake A0, the combustion air intake A1, the combustion air outlet A2, the water supplementing B, the process water supplementing B1, the desulfurization water supplementing B2, the dust exhaust D, the heat user backwater H0, the low Wen Cejin water outlet H1, the partition wall condenser water outlet H2, the preheated heat user backwater H3, the heating water outlet J1, the heating water inlet J2, the washing solution Na, the ammonia water NH3, the sewage side secondary steam Q, the condensation water QN, the hot water R, the high Wen Cejin water R1, the high temperature side water outlet R2, the cooling tower water inlet R3, the cooling tower backwater R4, the desulfurization tower water outlet S, the desulfurization circulating backwater SH, the desulfurization circulating water supply SG, the separation pool pollution discharge SS, the high temperature dust remover inlet flue gas Y1, the high temperature dust remover outlet flue gas Y2, the denitration device outlet flue gas Y3, the boiler outlet flue gas Y4, the desulfurization tower outlet flue gas Y5 and the condensation water film decontamination module outlet flue gas Y6.

Detailed Description

FIG. 1 is a schematic diagram and embodiment of a system of the present invention.

Specific example 1 of the present invention is as follows. The utility model provides a boiler discharges fume total composition and controls and resource recovery mode based on waste heat drive, adopt by the haze removal system of a set of flue gas total composition control and resource recovery utilization's technological process constitution, resource recovery technological system in order to reduce the vapor in the flue gas by a wide margin, but escape particulate matter and filterable particulate matter including the soluble salt of nanoscale scale, acid gas including sulfur dioxide and hydrogen chloride, the haze removal technological process and the resource conversion and recovery technological process of comprehensive elimination or effective suppression atmospheric haze influencing factor that leads to and realizing waste heat recovery drive that discharges fume, its characterized in that: the boiler smoke exhaust full-component treatment and recycling recovery mode and the system process flow thereof comprise a high-temperature or medium-low-temperature dust removal process, a cascade condensation waste heat recovery and water film decontamination process, a medium-temperature section smoke heat recovery process, a condensate recycling process for desulfurization water supplementing and desalted water preparing process, a desulfurization wastewater zero emission and recycling recovery process, wherein the specific process flow comprises the following steps:

If the high-temperature dust remover 2 is not arranged, a conventional medium-low temperature dust remover 2d is arranged, wherein the smoke inlet of the conventional medium-low temperature dust remover 2d is communicated with the smoke outlet of the boiler 2, and the smoke outlet of the conventional medium-low temperature dust remover 2d is communicated with the smoke inlet of the desulfurizing tower 7 or the medium-temperature section smoke heat recoverer 6.

If the desulfurization tower 7 for wet desulfurization is not arranged, but a high-temperature dry or semi-dry desulfurization device in the furnace is arranged, the circulating water outlet of the buffer tank 7a is changed to be a water inlet communicated with a water outlet pipe of the water supplementing B, and the water outlet of the desulfurization wastewater P1 of the buffer tank 7a is still communicated with the feed inlet of the wastewater pretreatment tank 8a of the desulfurization wastewater waste heat evaporation salt-separating crystallization module 8 which is used for carrying out wastewater zero discharge and salt-separating crystallization on part of the external wastewater from the water supplementing B.

The above embodiment 1 is suitable for comprehensive treatment and resource development and utilization of the boiler exhaust gas in new construction projects, and deep haze removal treatment and resource development and utilization of industrial kiln or process flue gas in new construction or reconstruction and expansion projects, but generally, for existing coal-fired boiler systems, the tail heating surface of the flue gas, even a denitration device and the like are integrated in the boiler body, and there is not enough space to install a high-temperature dust collector in the boiler body, or the middle-high-temperature flue gas is led out to the high-temperature dust collector and then returned to the original flue, so that the method is difficult to directly apply, and the modification can be performed according to the method of the following specific embodiment 2.

Specific example 2 of the present invention is as follows.

If the high-temperature dust collector 2 is not suitable for being arranged due to the field installation space and the like, a conventional medium-low temperature dust collector 2d can be arranged instead, wherein the flue gas inlet of the conventional medium-low temperature dust collector 2d is communicated with the flue gas outlet of the boiler 2, and the flue gas outlet of the conventional medium-low temperature dust collector 2d is communicated with the flue gas inlet of the desulfurizing tower 7 or the medium-temperature section flue gas heat recoverer 6. Other system flow and features of this embodiment are the same as those of embodiment 1.

Specific example 3 of the present invention is as follows.

If the existing boiler adopts a dry or semi-dry desulfurization mode, i.e. a wet desulfurization tower 7 is not arranged, the flue gas outlet of the medium-temperature section flue gas heat recoverer 6 is communicated with the flue gas inlet of the cascade condensation water film decontamination module 9 instead. Other system flow and features of this embodiment are the same as those of embodiment 1 described above. At this time, the smoke cleanliness after dry desulfurization, high-temperature dust removal and high-temperature denitration is very high, and the smoke sides of various heat exchangers on the smoke channel, including the heat exchange elements of a medium-low temperature smoke heating surface 1b, an existing air preheater of a boiler, a medium-temperature section smoke heat recoverer 6 and the like all solve the inherent problems of scale formation and blockage, efficiency reduction, periodic ash removal, maintenance, corrosion acceleration and the like.

It should be noted that the present invention provides a full-component deep treatment and a recycling method for boiler exhaust gas to eliminate the influence factors on haze and surrounding environment pollution, and provides a specific implementation method, a flow and an implementation device for realizing the above purpose by adopting a step haze removal method, a waste heat utilization method and a recycling backwater method, and according to the general solution, there may be different specific implementation measures and specific implementation devices with different structures, the above specific implementation is only one of them, and any other similar simple deformation implementation is adopted, for example, different heat exchange structures are adopted; adding or reducing a plurality of layers of step treatment measures; or simply adjusting the connection method, the water inlet and outlet sources and the grading quantity of the waste heat water system; or the like, or the technical mode is applied to different power equipment smoke discharging or air discharging types, and the like and other similar application occasions with the same or similar structures, which are all conceivable by ordinary professionals.

Claims

1. The utility model provides a boiler smoke total composition is administered and resource recovery process flow based on waste heat drive, adopt by the haze removal system of a set of smoke total composition of treatment and resource recovery utilization's process flow, resource recovery process system in order to reduce the vapor in the flue gas by a wide margin, but escape particulate matter and filterable particulate matter including the soluble salt of nanoscale scale, acid gas including sulfur dioxide and hydrogen chloride, the atmosphere haze influencing factor that the comprehensive elimination or effective suppression caused of discharging fume and realization waste heat recovery driven removes haze process flow and resource conversion and recovery process flow, its characterized in that: the boiler smoke exhaust full-component treatment and recycling recovery process flow comprises a high-temperature or medium-low-temperature dust removal process, a cascade condensation waste heat recovery and water film decontamination process, a medium-temperature section smoke heat recovery process, a condensate recycling process for desulfurization water supplementing and desalted water making process, desulfurization wastewater zero emission and recycling recovery process, wherein the specific process flow comprises the following steps:

Firstly, a high-temperature dust remover (2) is arranged at a flue gas outlet of a medium-temperature flue gas heating surface (1 a) with the outlet flue gas temperature between 300 and 350 ℃ in a tail heating surface of a boiler (1), and flue gas subjected to high-temperature dust removal is sent into a denitration device (3), so that the technical condition for generating denitration catalyst poisoning is eliminated, high-efficiency and low-cost stable medium-high Wen Tuoxiao is realized, and the high-temperature dust remover (2) is used for recycling dust resources used as building materials;

Secondly, the primary purified flue gas after high-temperature dust removal and medium-high temperature denitration enters an existing medium-low temperature flue gas heating surface (1 b) of a boiler and carries out high-efficiency stable heat exchange under the technical condition of avoiding dust scaling, and then enters a medium-temperature section flue gas heat recoverer (6) to recover the sensible heat of the primary purified flue gas and serve as a heating source of a waste heat air preheater (4) and a waste heat evaporation crystallizer (8 b), wherein the waste heat air preheater (4) carries out second-stage sensible heat preheating on boiler combustion-supporting air;

thirdly, the flue gas continuously enters a desulfurization tower (7) for desulfurization, and the desulfurization wastewater is sent to a desulfurization wastewater waste heat evaporation salt separation crystallization module (8) to recover water resources, industrial raw material resources including industrial sodium chloride and building material raw material resources including gypsum and heavy metal stabilizing compounds;

Fourthly, the desulfurized flue gas is sent into a flue gas inlet of a cascade condensation water film decontamination module (9) for deep purification, and sequentially passes through a flue gas inlet section (9 k) and a multistage washing condensation water film decontamination device from bottom to top, and is sent out to the atmosphere through a flue gas outlet at the top of the cascade condensation water film decontamination module (9) for diffusion and discharge, wherein during the diffusion and discharge, water vapor in the flue gas, escapable particles including soluble salt with nanoscale scale, filterable particles and acid gas including sulfur dioxide and hydrogen chloride are absorbed and intercepted by spraying circulating water and condensation water and are settled in a tower bottom water pool (9 l), and redundant condensation water in the tower bottom water pool (9 l) is used as circulating water supplementing of a desulfurizing tower and process supplementing water including a desalting water preparation process in a factory;

Fifthly, the high-temperature residual hot water in the tower bottom water tank (9 l) is sent to the residual heat user heater (10) for preheating heating backwater and process backwater, and part of the cooled residual heat water is sent to the full-heat air preheater (11) for carrying out first-stage full-heat preheating on boiler combustion-supporting air, so that cascade recycling of flue gas residual heat resources, particularly latent heat residual heat, is realized;

The rest part of the cooled waste heat water of the waste heat user heater (10) is used as a medium-low temperature cold source to spray through a circulating spray device (9 f) and then drives a lower washing heat exchanger (9 g) to perform condensation heat exchange and wash smoke, the waste heat water outlet of the total heat air preheater (11) is used as a low temperature cold source to spray through a washing spray device (9 c) and then drives an upper washing heat exchanger (9 d) to perform deeper condensation heat exchange and wash smoke, and meanwhile, part of the hot user backwater (H0) is used as a medium-low temperature cold source to be sent into a partition wall condenser (9H) to perform partition wall condensation heat exchange on the smoke and enable the smoke condensation water to form a water film on the outer wall surface of the partition wall condenser (9H) to purify the smoke through absorption adsorption;

seventhly, secondary steam (Q) on the sewage side of the waste heat evaporation crystallizer (8 b) is sent into a secondary steam heat recoverer (8 c) to release heat and condense, then water resources of condensed water (QN) are recovered, secondary waste heat water outlet (J2) on the heated side is used as a reheating heat source to be sent into a white heat elimination heat exchanger (9 a) to realize reheating and heating of low-temperature low-humidity purified flue gas, and high-altitude diffusion and emission are realized after floating force is improved.

2. The system for realizing the waste heat driven boiler exhaust gas total composition treatment and recycling recovery process flow comprises a high-temperature or medium-low-temperature dust removal module, a cascade condensation waste heat recovery and water film decontamination module, a medium-temperature section flue gas heat recovery module, a condensate recycling water supply and desalting water preparation module and a desulfurization wastewater zero discharge and recycling recovery module, wherein the specific process system comprises the following steps:

i. The flue gas inlet of the high-temperature dust remover (2) is connected with the flue gas outlet of a medium-temperature flue gas heating surface (1 a) with the outlet flue gas temperature between 300 and 350 ℃ in the tail heating surface of the boiler (1), the flue gas outlet of the high-temperature dust remover (2) is connected with the flue gas inlet of the denitration device (3), the flue gas outlet of the denitration device (3) is connected with the flue gas inlet of a medium-low-temperature flue gas heating surface (1 b), and the bottom of the high-temperature dust remover (2) is provided with a discharge hole for dust (D);

The outlet flue gas of the medium-low temperature flue gas heating surface (1 b) is connected with the flue gas inlet of the medium-temperature section flue gas heat recoverer (6) through the flue gas outlet of the boiler body air preheater, the flue gas outlet of the medium-temperature section flue gas heat recoverer (6) is communicated with the flue gas inlet of the desulfurizing tower (7), the heated water outlet of the medium-temperature section flue gas heat recoverer (6) is respectively connected with the high Wen Cejin water gap of the waste heat air preheater (4) and the high Wen Cejin water gap of the waste heat evaporation crystallizer (8 b), the heated water inlet of the medium-temperature section flue gas heat recoverer (6) is respectively connected with the high-temperature side water outlet of the waste heat air preheater (4) and the high-temperature side water outlet of the waste heat evaporation crystallizer (8 b), the outlet of the air outlet (A2) of the waste heat air preheater (4) is connected with the combustion-supporting air inlet of the boiler body air preheater, and the inlet of the air inlet (A1) of the waste heat air preheater (4) is connected with the combustion-supporting air outlet of the full heat air preheater (11);

The water (S) discharged from the desulfurizing tower (7) enters a buffer tank (7 a), a water outlet pipe of the desulfurization circulating backwater (SH) at a circulating water outlet of the buffer tank (7 a) is communicated with a water inlet pipe of the desulfurization water supplementing (B2) and a water inlet pipe of the desulfurization circulating water Supply (SG), the buffer tank (7 a) is also provided with a discharging port of gypsum (SS) and a water outlet of desulfurization wastewater (P1), wherein the water outlet of the desulfurization wastewater (P1) is communicated with a feed port of a wastewater pretreatment tank (8 a) of a desulfurization wastewater waste heat evaporation and salt separation crystallization module (8), the waste water pretreatment tank (8 a) is also provided with a dosing inlet of a reagent (G), a discharge port of desulfurization solid waste (SP) of building materials including gypsum and heavy metal stabilizing compounds and an outlet of desulfurization waste water pretreatment water (P2), the outlet of the desulfurization waste water pretreatment water (P2) is connected with a feed port of a waste heat evaporation crystallizer (8B), the waste heat evaporation crystallizer (8B) is also provided with a discharge port of industrial sodium chloride (NC) and an outlet of sewage side secondary steam (Q), the outlet of the sewage side secondary steam (Q) is connected with a steam inlet of a secondary steam heat recoverer (8 c), the secondary steam heat recoverer (8 c) is also provided with a water outlet of secondary steam condensate (QN) and a water inlet and a water outlet of low-temperature side heated water, the outlet of the secondary waste heat water outlet (J2) of the secondary steam heat recoverer (8 c) is connected with the water inlet of the white heat elimination heat exchanger (9 a), and the inlet of the secondary waste heat water inlet (J1) of the secondary steam heat recoverer (8 c) is connected with the water outlet of the white heat elimination heat exchanger (9 a);

and iv, a flue gas outlet of the desulfurizing tower (7) is connected with a flue gas inlet of the cascade condensation water film decontamination module (9), and the internal scale of the cascade condensation water film decontamination module (9) sequentially comprises the following condensation washing purification process structures or devices from bottom to top: the flue gas inlet section (9 k) and the multi-stage washing condensation water film decontamination device are arranged, a flue gas outlet at the upper part of the multi-stage washing condensation water film decontamination device is communicated with the external atmosphere through a flue gas outlet at the top of the cascade condensation water film decontamination module (9), and a tower bottom pool (9 l) is arranged at the lower part of the flue gas inlet section (9 k);

The high-temperature waste heat water outlet of the tower bottom water tank (9 l) is respectively communicated with the water outlet pipe of the water supplementing (B) and the inlet of the high Wen Cejin water (R1) of the waste heat user heater (10) and the circulating water inlet of the cooling tower after passing through the circulating water pump, the water outlet pipe of the water supplementing (B) is communicated with the water supplementing pipe of the desulfurization water supplementing (B2) and the water supplementing pipe of the process water supplementing (B1) including the desalted water in the factory, the outlet of the high-temperature side water outlet (R2) of the waste heat user heater (10) is respectively communicated with the middle-low temperature cold source through the water inlet of the circulating spraying device (9 f) and the water inlet of the total heat air preheater (11), the low-temperature side inlet of the waste heat user heater (10) is respectively communicated with the water return pipe of the hot user backwater (H0) and the water inlet of the partition wall condenser (9H), and the outlet of the water outlet of the partition wall condenser (9H) and the preheated backwater of the hot user (H3) after preheating;

A water outlet of a water tank at the bottom of the total-heat air preheater (11) is communicated with a water inlet of a washing spray device (9 c), an air inlet of the total-heat air preheater (11) is communicated with a boiler air inlet (A0), and an air outlet of the total-heat air preheater (11) is communicated with an inlet of a combustion-supporting air inlet A1 of the waste heat air preheater (4); the multistage washing condensation water film decontamination device inside the step condensation water film decontamination module (9) sequentially comprises the following condensation washing purification technological processes and devices from bottom to top: the device comprises a washing condensation rain area (9 j), a one-way rectifier (9 i), a partition wall condenser (9 h), a lower washing heat exchanger (9 g), a circulating spray device (9 f), a washing demister (9 e), an upper washing heat exchanger (9 d), a washing spray device (9 c), a demister (9 b) and a white heat elimination exchanger (9 a), wherein the upper air outlet side of the white heat elimination exchanger (9 a) is communicated with the top smoke outlet of a step condensation water film decontamination module (9); the high-temperature dust collector (2) adopts a bag type dust collector structure made of basalt filtering materials.

3. The system based on the waste heat driven boiler exhaust gas total composition treatment and recycling process flow of claim 2, which is characterized in that the total heat air preheater (11) adopts a direct contact type spray heat exchange tower structure with the function of heating and humidifying boiler combustion air.

4. The system based on the waste heat driven boiler exhaust gas full-component treatment and recycling recovery process flow is characterized in that an extrusion molding aluminum fin heat exchange tube structure coated with graphene materials is adopted by the medium-temperature flue gas heating surface (1 a), the medium-low-temperature flue gas heating surface (1 b), the waste heat air preheater (4), the medium-temperature section flue gas heat recoverer (6), the white heat elimination heat exchanger (9 a) and the partition wall condenser (9 h).

5. The system based on the waste heat driven boiler exhaust gas total composition treatment and recycling process flow according to claim 2 is characterized in that if the high-temperature dust remover (2) is not arranged, a conventional medium-low temperature dust remover (2 d) is arranged, wherein the flue gas inlet of the conventional medium-low temperature dust remover (2 d) is communicated with the flue gas outlet of the boiler (1), and the flue gas outlet of the conventional medium-low temperature dust remover (2 d) is communicated with the flue gas inlet of the desulfurizing tower (7) or the medium-temperature section flue gas heat recoverer (6).

6. The system based on the waste heat driven boiler exhaust gas full-component treatment and recycling process flow according to claim 2 is characterized in that if the desulfurization tower (7) is not arranged, but an in-furnace high-temperature dry or semi-dry desulfurization device is arranged, the circulating water outlet of the buffer tank (7 a) is changed into a water inlet communicated with a water outlet pipe of the water supplementing (B), and the water outlet of the desulfurization waste water (P1) of the buffer tank (7 a) is still communicated with the feed inlet of the waste water pretreatment tank (8 a) of the desulfurization waste water waste heat evaporation salt-separating crystallization module (8) which is used for carrying out sewage zero discharge and salt-separating crystallization on part of the external drainage of the water supplementing (B).

7. The system based on the waste heat driven boiler exhaust gas total composition treatment and recycling recovery process flow of claim 2, which is characterized in that the lower washing heat exchanger (9 g) and the upper washing heat exchanger (9 d) are both made of strong acid and alkali corrosion resistant and scaling and fouling resistant condensation heat exchange materials.

8. The system for full-component treatment and recycling of boiler exhaust gas based on waste heat driving process flow according to claim 2, wherein the inlet washing solution (Na) of the washing spray device (9 c) adopts sodium hydroxide dilute solution with pH value of 7-10.