CN210153846U - Flue gas haze removal and white elimination process system based on waste heat driving - Google Patents

Abstract

A flue gas haze removal and white elimination process system based on waste heat driving belongs to the technical field of flue gas treatment and boiler heat supply. Aiming at the problem that the tail plume of wet-process desulfurization flue gas or dry-process desulfurization flue gas of a boiler carries more particle pollutants, particularly a large amount of nano-scale penetrable particles (PM 0.3 and below) and acid gas, belongs to the main cause of haze, and can be suspended in the atmosphere for a long time and accumulated continuously, a high-temperature dust remover is adopted to improve the efficiency of a denitration device and eliminate the source of catalyst poisoning, a step condensation water film decontamination module is adopted to greatly reduce the acid gas such as water vapor, sulfur dioxide and the like, Filter Particles (FPM), Condensable Particles (CPM) and soluble particles (DPM), wherein the flue gas flows upwards from the lower part of the denitration device and sequentially passes through a washing condensation rain zone, a one-way rectifier, a dividing wall condenser, a lower washing heat exchanger, a washing demister, an upper washing heat exchanger, a demister, a white elimination heat exchanger and.

Description

Flue gas haze removal and white elimination process system based on waste heat driving

Technical Field

The utility model relates to a flue gas removes haze and white processing system that disappears based on waste heat drive belongs to flue gas treatment and boiler heat supply technical field.

Background

The smoke discharged by boilers and various industrial kilns which adopt fossil fuels such as coal and natural gas for combustion and heating contains a large amount of water vapor and a plurality of gaseous and solid pollutants, which become important pollutant sources influencing the atmospheric environment, the existing treatment of haze, visual whitening and the like belong to the focus environmental protection problems concerned by the public society and policy departments, the academic communities and many industrial enterprises also pay a lot of efforts and attempts to fundamentally solve the problem and make progress, even more than ten provinces including Shanghai, Tianjin, Hebei and the like have developed local standards related to whitening, and other places and industries also seek to provide standards and policies so as to facilitate the deep work of atmospheric treatment. However, the understanding and comprehension of the haze cause and the influence of smoke on the haze mechanism and degree and the like at present still need to be deepened, so that the direction, mode and method of smoke discharge treatment of coal-fired boilers and the like still need to be deeply researched, the matching solutions and systems, technical effects, investment, operation economy, enterprise bearing capacity and the like of industry enterprises need to be deeply researched, and a plurality of important problems and phenomena existing in the field of smoke treatment of boilers or kilns and the like at present comprise: one is the mechanism and degree of the effect of boiler exhaust smoke on haze; secondly, the smoke components and the influence mechanism on haze of the smoke discharged from the boiler after the ultralow emission treatment are carried out; thirdly, the smoke is deeply treated to fundamentally eliminate or at least remarkably slow down the contribution degree of the smoke to haze; and fourthly, realizing key technology of a technical approach, determining whether key equipment has feasibility and technical effects and influences on haze or whitening elimination, determining whether the key equipment has the technology, economic conditions, policy environment and the like for industrial popularization.

Several important background art of the present invention are described below.

The technical research background about haze formation.

In order to facilitate the discussion of technical approaches to solve the problems, 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 of exceeding the content of various suspended particulate matters in the atmosphere, and especially PM2.5 (particulate matters with aerodynamic equivalent diameter less than or equal to 2.5 micrometers) is considered as an 'allegory' causing the haze weather. Where the mist is an aerosol system consisting of a large number of tiny water droplets or ice crystals suspended in the air near the surface. Haze is an aerosol system consisting of dust, sulfuric acid (salt), nitric acid (salt) and other particles in the air and causes visual disturbance, wherein the particles are the main cause of aggravating haze weather pollution, and the particles are not only pollutants, but also carriers of heavy metals, polycyclic aromatic hydrocarbons and other toxic substances. The haze particles are distributed uniformly, the size of the dust haze particles is small, the dust haze particles are 0.001-10 micrometers, the average diameter of the dust haze particles is about 1-2 micrometers, and the floating particles in the air cannot be seen by naked eyes.

Aerosols (aerosol) are colloidal dispersions, also known as gas dispersions, of small particles of a solid or liquid dispersed and suspended in a gaseous medium. The dispersion phase is solid or liquid small particles with the size of 0.001-100 microns, and the dispersion medium is gas. The liquid aerosol particles are generally spherical and the solid particles are irregular in shape, typically having a radius of 0.001 to 0.1 microns. The concentration of small particle size aerosols is limited by agglomeration and the concentration of large particles is limited by settling. The chemical composition of the aerosol is quite complex, and the aerosol contains various trace metals, inorganic oxides, sulfates, nitrates, oxygen-containing organic compounds and the like. The sulfate formed by the conversion of sulfur dioxide in the atmosphere is one of the main components of the aerosol. Sulfur is the most important element in the aerosol and its content reflects the global migration, transport and distribution of the contaminants. The mechanism of formation of nitrate and organic matters in aerosol is yet to be studied. The content of various elements of the aerosol from soil is not greatly different among regions; there are large regional differences in the various elements (such as chlorine, tungsten, silver, manganese, cadmium, zinc, antimony, nickel, arsenic, chromium, etc.) that originate in industrial areas.

Weather experts show that haze weather is influenced by weather conditions and is related to increase of atmospheric pollutant emission, and the following three main reasons are adopted for the haze weather caused in winter: firstly, the cold air activity is weaker than usual, the wind speed is low, and pollutants are easy to accumulate on the near-ground surface layer, so that the haze weather is frequent; secondly, the aerosol background concentration in winter in China is high, and haze formation is promoted; and thirdly, the atmosphere in the stratum is more stable in the haze weather, the haze development can be aggravated, and the atmospheric pollution is aggravated. The source of haze is various, for example automobile exhaust, industry emission, building raise dust, msw incineration, volcanic eruption even etc. and haze weather is the mixed effect formation of multiple pollution sources usually.

Haze is harmful to human bodies after being inhaled into the respiratory tract of people, and if the haze is inhaled for a long time, serious people can die. From the view of the harm to the respiratory tract of a human body, particles with the diameter of more than 10 microns are usually retained in the nasal cavity and the nasopharynx and larynx; particles of 2 to 10 μm mostly remain in the upper respiratory tract, while particles of 2 μm or less increase in the retention rate in the lung with decreasing particle size, and particles of 0.1 μm or less increase in the attachment rate in the bronchus with decreasing particle size. As the diameter of fine powder-like floating particles in haze is generally below 0.01 micron, the fine powder-like floating particles can directly enter the bronchus and even the lung through a respiratory system. Therefore, the greatest influence of haze is the respiratory system of a human, and the caused diseases are mainly concentrated on respiratory diseases, cerebrovascular diseases, nasal inflammation and other disease types.

In summary, the haze is a stable aerosol state in the atmosphere under certain meteorological conditions, and the acidic gas such as sulfur dioxide, nitrogen oxide, particulate matters and the like in the atmosphere jointly act, wherein the smaller particle size of the particulate matters, i.e. the particulate matters within the range of 0.001-0.1 micron, is easier to form a stable aerosol state, and is also one of the main factors for forming the haze; meanwhile, the threat to human health is generally considered to be more serious, and certainly, the method is also one of the main efforts for removing haze.

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

In recent years, multiple rounds of general environmental protection emission reduction and efficiency improvement are implemented for pollution enterprises such as coal-fired power plants, great success is achieved, and especially ultra-low emission indexes are generally realized for the coal-fired power plants, namely smoke dust is not higher than 5mg/Nm, sulfur dioxide is not more than 35mg/Nm and nitrogen oxide is not more than 50mg/Nm in thin-year trees, but air pollution is not fundamentally solved, and heavy haze pollution is still caused in the weather. At present, the existing national standard for measuring particulate matters in China (GB 16157-1996) only measures particles larger than 0.45 micrometer (PM 0.45), and the existing detection means cannot complement nano-scale particulate matters (the particle size is from several nanometers to several hundred nanometers). Whether particulate matter smaller than PM0.45 will be another major cause of haze is determined by the fact that white flue gas generated by a wet desulfurization unit contains a large amount of Dissolved particles (TDS-Total dispersed Solids), which is the sum of solid particulate matter Dissolved in liquid, and the particle size of the solid particulate matter is usually between a few tenths of nanometers and hundreds of nanometers (most of the particles are smaller than the currently monitored PM 0.45). The flue gas at the outlet of the wet desulfurization device contains a large amount of supersaturated water vapor, so that a chimney has a phenomenon of 'white plume-shaped mist trailing', and the actual measurement proves that the flue gas contains a large amount of water 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 with extremely fine particles along with the evaporation of water, and the nanoscale dissolved particles can be suspended in the atmosphere for a longer time and are continuously accumulated. Typically, PM2.5 particles can be suspended in the atmosphere for 100 hours, PM1 particles can be suspended in the atmosphere for 1000 hours, and such smaller particles (PM 0.45 or less) are suspended for longer periods of time, are more difficult to settle, and tend to rapidly agglomerate with weather and humidity conditions, forming aerosols (aerosols), and causing haze contamination.

And in 2017, the measurement is carried out on the No. 1 unit of the Tianjin national electro-rheological fluid limited company from 8 months 15 days to 8 months 30 days. The environmental protection facilities such as denitration, dust removal and desulfurization of the unit and main engineering are put into operation at 8 months and 12 days in 2009 simultaneously. The environmental protection detection of the unit reaches the standard (the particulate matter emission is less than 10mg/Nm 3). Three groups of data are obtained through a method of washing with distilled water, and therefore, the dissolved particles are reasonably presumed to be the important reason that the haze is not cured for a long time, and the actual measurement result is analyzed as follows.

(1) In the test, after limestone-gypsum wet desulphurization, 87 mg/standard cubic meter of dissolved particles in the flue gas are discharged; after passing through the wet electric dust collector, 76 mg/standard cubic meter still remained. These two data are far above the existing national standard for ultra clean emissions with particulate emissions of less than 10 mg/standard cubic meter. This indicates that: 1) a large amount of dissolved particles are generated and discharged after wet desulfurization; 2) the wet electric dust collector has little effect on removing the dissolved particles and cannot be used as an equipment option for removing the dissolved particles; 3) these dissolved particles are extremely fine and missed, escape the line of sight of people, are unobstructed, and are "lawfully" discharged into the atmosphere.

(2) Calculating the discharge amount of dissolved particles and evaluating pollution. The amount of the discharged dissolved particles measured by the unit (with the capacity of 330 MW) can be calculated to be about 131 kg/h; the dissolved particle discharge of the boiler fume of the 1000MW unit is 397 kg/h. The haze 'bursting table' concentration is 500 mug/m 3, and the dissolved particle amount discharged by the power plant per hour can enable the atmospheric space of about 2km (length), 2km (width), 200m (height) to reach the 'bursting table' concentration under the condition of poor diffusion.

(3) The total installed capacity of coal used for power generation in China is about 9.0625 hundred million kilowatts, and 99 percent of the coal is additionally provided with a wet desulfurization device. Reckoned from the above data, only one dissolved particle for coal fired power plant desulfurization is emitted up to about 260 million tons/year. The users such as coking, steel making, chemical industry, cement, industrial boilers and the like are not included. Furthermore, "splash-evaporate" cooling is also a large discharge of dissolved particles. If these are included, it is estimated that the dissolved particulate (TDS) emissions will be near or above 1000 million tons/year. This total amount of pollutants exceeds even the total amount of dust emissions we know, plus a longer suspension time. It can thus be derived: dissolved particles are another important cause of haze.

(4) And (4) analyzing the pH value of the water vapor in the flue gas. The pH value is measured to be 2-3, and acid rain is formed when the water vapor enters the atmosphere and rains (the annual emission amount of the strong acid water vapor is more than 9 hundred million tons). The reason is that more SO2 in the flue gas is converted into SO3 by catalytic denitration (SCR), and the SO3 is extremely difficult to remove by the current wet desulfurization; and the phenomenon of ammonia escape in denitration is added, so that steam in the flue gas is strongly acidic.

In summary, the flue gas of the coal-fired boiler after wet desulfurization contains a large amount of dissolved particles with small particle sizes, and the actual content of the dissolved particles reaches 70-100 mg/Nm grade under the condition of realizing 'ultra-low' emission, which is equivalent to or even greater than the sum of the contents of three types of detection pollutants which realize 'ultra-low' emission at present, so that the dissolved particles are not really ultra-low emission, but are not paid enough attention to people because the dissolved particles are not brought into the monitoring range at present, but are difficult to be captured by a wet electric dust collector behind a desulfurizing tower together with escaped acid gas, so that the dissolved particles are discharged into the atmosphere in a large amount, and become one of the main factors influencing the atmospheric environment and haze formation in the flue gas at present.

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

At present, more than ten provinces and cities including Shanghai, Tianjin, Hebei and the like develop local standards related to 'white elimination', wherein southern areas such as Shanghai and the like often require that smoke dust and smoke are diffused at high altitude in a larger range by increasing the temperature of the smoke so as to reduce dust pollution to the ground and adjacent air and realize visual 'white elimination'. Unlike southern regions, however, the north whitening standard does not require complete removal of white visual pollution in winter, for example, geopolitical departments such as Tianjin, Hebei require the goal and substance of whitening: the condensation heat exchange is adopted to effectively reduce the water vapor content, effectively reduce haze pollutants such as soluble salt and the like, and reduce the visual pollution of white smoke.

The possibility of achieving complete visual depigmentation in northern areas and its technical approach are discussed below.

(1) The mechanism for the difficulty of visual whitening in northern areas is as follows: for example, if the exhaust gas dew point temperature of the gas-fired boiler is 57 ℃, the water vapor content of 1kg of dry flue gas is about 128 g; the maximum content of the product is only 2.5g when the product is saturated with air at-5 deg.C. When the temperature of the smoke is reduced to 30 ℃, the smoke is about 27g, so that the water vapor can be reduced by 79 percent, and the length of the white smoke trail can be greatly shortened to 10 to 20 percent of the original length; however, the water vapor content of the smoke-air pollution-free air conditioner still exceeds the maximum allowable value of the external temperature in winter by an order of magnitude, so that the visual pollution of white smoke is difficult to completely eliminate even if the smoke temperature is increased by 30-50 ℃.

(2) The white elimination policy in northern areas and the basis thereof are as follows: for example, the technical basis of local policy documents such as Hebei province and Tianjin City is not complete visual whitening elimination, but focuses on reducing the condensation temperature of the flue gas by about 4-5 ℃, and by condensation of partial water vapor, other pollutants (such as soluble salt, desulfurized gypsum, heavy metal, sulfur dioxide, hydrogen chloride, smoke dust content indexes and the like) except NOx in the flue gas can be remarkably reduced, influence factors such as tail pollution and haze are reduced as much as possible, and the visual length of the tail trace of the 'white smoke' is partially reduced.

(3) The technical conditions and the approach to completely eliminate the visual white fog contamination were analyzed as follows.

a) The exhaust gas temperature is reduced to an external temperature, for example, -5 c or less, thereby eliminating the chimney opening white fog phenomenon, but the actual cost is extremely large.

b) If the exhaust gas temperature is reduced to 30-35 ℃, and then the exhaust gas is heated to about 150-200 ℃, visual whitening can be realized when the temperature is not lower than-5 ℃ outside the day, but the heating cost is too high, the energy consumption is too high, and the emission of pollution is increased.

c) If the exhaust smoke is deeply cooled to about 15 ℃ by adopting a heat pump and the like and then heated to about 40-50 ℃, visual whitening can be basically realized when the outside temperature is not lower than-5 ℃ in the daytime, but white fog can still appear when the outside temperature is continuously reduced to below-10 ℃ for example.

In conclusion, the key problems, essentials and environmental protection values of the whitening are firstly to greatly reduce the key factors of various pollutants such as soluble salt, heavy metal, acid gas and the like which affect haze and harm human health, and secondly to reduce and eliminate the visual pollution of 'white fog', if the visual pollution is mainly solved and various pollutants contained in smoke cannot be effectively treated, the 'whitening' is increased by a large amount of electric energy, reheat steam heat energy and the like, the energy consumption and corresponding pollution emission are increased in vain, and no practical significance is achieved, and the so-called 'whitening' behavior of inversion and fringed fish is proved carefully and even cancelled.

And (IV) the technical development of the prior patents is reviewed.

(1) The latest development of the flue gas waste heat deep recovery and white elimination technology:

various flue gas waste heat recovery patent technologies are developed and popularized by combining scientific research institutions such as Qinghua university and enterprises, wherein the serialized patent technical achievement of ' flue gas waste heat recovery and heat supply technology based on steam heat-carrying circulation ' comprises ' a boiler exhaust smoke heat and humidity direct recovery method and device based on steam heat-carrying circulation ' (2017104371042) ' a boiler exhaust smoke total heat recovery and flue gas whitening device integrating smoke and tower ' (2017206805342) ', and the like, which are successfully verified through demonstration engineering and listed in the 8 th-batch energy-saving technology popularization catalogue in 2018 years in Shandong province, can reduce the exhaust smoke temperature to about 30 ℃ by adopting a direct heat exchange mode instead of a heat pump, and reduce the water vapor content in the flue gas by over 70-80 percent while recovering a large amount of steam latent heat and water resources, thereby realizing remarkable whitening; meanwhile, the method can reduce 30-50% of filterable particles (flue gas on-line monitoring parameters), more importantly, can basically reduce soluble acid gases such as sulfur dioxide and hydrogen chloride to 0, and can reduce gypsum, soluble salt, heavy metal and the like by more than 60-80%, namely, a plurality of key factors in haze causes are obviously eliminated.

(2) Accurate measurement of smoke constituents and their effect on haze.

By adopting a novel high-precision nano-scale particle detection instrument and a 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 by expert teams such as stone love army, Beijing national academy of sciences, Beijing He Chen intelligent energy science and technology, Inc., Zhao Jianfei and the like, and the distribution conditions of 11 main ions in the flue gas are shown as follows: ions containing sulfate radicals and sulfite radicals account for more than 82% of the total mass and are the main sources of PM 2.5; nitrite content is also relatively high, so it is necessary to include fugitive particulates, such as soluble particulates, within the monitoring and remediation window.

(3) The technical development of the high-temperature dust remover.

The filter material made of basalt and the like and the bag type dust removal device thereof are successfully developed, and the static dust removal bag type dust remover technology is developed and successfully popularized, so that the high-efficiency, stable and reliable dust removal can be realized at about 300-350 ℃ of medium-high temperature flue gas, and the catalytic effect of the medium-high temperature denitration catalyst can be obviously improved, thereby improving the denitration performance index, avoiding the catalyst poisoning and effectively reducing the investment and the operation cost. The high temperature dust remover can regard as environmental protection island first order device, can effectively solve the interval difference problem of current technology dust remover and denitrification facility temperature, and the denitration needs high temperature to realize high efficiency and removes dust and can't tolerate the interval problem of denitration temperature. Meanwhile, the high-temperature dust removal technology fundamentally eliminates the poisoning source of the denitration catalyst; the high-temperature dust remover is used as a first-stage device of the environmental protection island, so that the problem of heat exchange efficiency attenuation of the waste heat boiler and the problem of system instability caused by large-scale resistance can be greatly improved.

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

The successfully developed extrusion-molded aluminum fin type heat exchanger adopting graphene for surface corrosion prevention can replace the heat exchanger adopting expensive metal or fluoroplastic and other special materials in the prior art, has the advantages of strong acid and strong 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 that boiler flue gas has strong corrosion and even deep condensation.

In conclusion, the current situation relates to the technical research and promotion results of the prepositive technology of flue gas waste heat recovery, the flue gas component depth analysis, the influence on haze and the like, and provides important technical conditions for the development of the haze prevention full-component treatment technology of flue gas.

SUMMERY OF THE UTILITY MODEL

The utility model aims at and the task be, it that shows to the full component analysis of above-mentioned boiler exhaust fume has a large amount of soluble salt to escape etc. is showing the problem that influences haze formation and contaminated air, adopt the hierarchical processing system technique, and multiple key new technology achievement, realize that high temperature high efficiency removes dust, high-efficient denitration, waste heat driven step complete component process flows such as administer, effectively reduce the vapor in discharging fume, soluble salt, current situation evasive pollutant such as acid gas, thereby realize that boiler exhaust fume utensil prevents haze and white improvement of disappearing fundamentally.

The utility model discloses remove haze mechanism and technical approach brief description as follows. Firstly, a high-temperature dust remover is adopted to firstly remove dust from the flue gas 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 injection amplitude can be reduced, and the ammonia escape amount can be reduced. And secondly, the method is beneficial to reducing the poisoning of the desulfurizer in the desulfurizing tower and ensuring the operation stability of a desulfurizing system and the stability of a desulfurizing effect. Thirdly, in the deep dust-settling process, a wet electric dust collector which has no substantial effect on deep removal of dissolved particles and acidic gas is not adopted, but a brand-new step condensate water film decontamination module is adopted instead, and the adopted mechanism comprises the following steps: the flue gas at the outlet of the wet desulphurization is in a supersaturated aerosol state with fog and haze properties, wherein part of the nano-scale particles (0.001-0.3 micron) and the acid gas form a mixture with a settleable size by collision, agglomeration and the like with fog drops and particles with larger size, and the mixture is removed by removing the part of the liquid-solid mixture; various particulate matters and acid gases in the flue gas are carried and removed along with the condensed water through condensation heat exchange; a water bath principle, namely washing particulate matters, particularly dissolved particles and acidic gas in the flue gas through the spraying effect of circulating water; the water film dedusting principle is that a large amount of particulate matters, particularly dissolved particles and acidic gas in the flue gas are adsorbed and absorbed in a large amount by creating the action mechanisms of inertia collision, brownian motion, direct absorption and the like of direct contact, baffling and scouring and the like of a large amount of wall surface liquid films and the flue gas; the chimney hot-pressing and high-altitude diffusion principle is that smoke which greatly reduces smoke temperature and water vapor content is heated again, the buoyancy lift force and the thermal pressure difference are improved, and the air flow floating and high-altitude diffusion purification emission effects at the chimney opening are improved.

The utility model discloses a concrete description is: the utility model provides a flue gas removes haze and white process systems that disappears based on waste heat drive, adopts and controls the flue gas that is constituteed with the process flow that reduces the vapor in the flue gas by a set of flue gas total composition, the evasive particulate matter including nanometer yardstick's soluble salt and filterable particulate matter, acid gas including sulfur dioxide and hydrogen chloride including, and the key equipment in this system includes high temperature dust remover 2, step condensate film scrubbing module 9 and (or) middle temperature section flue gas heat recovery device 6, its characterized in that: 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-temperature and low-temperature flue gas heating surface 1b, the step condensation water film decontamination module 9 adopts an integrated step heat exchange washing tower structure, the flue gas inlet at the lower part of the tower body is communicated with the flue gas outlet of the desulfurization tower 7, the bottom of the tower body is provided with a tower bottom water tank 9l, the upper part of the tower bottom water tank 9l is provided with a flue gas inlet section 9k, and the flue gas sequentially passes through a washing condensation rain zone 9j, a one-way rectifier 9i, a dividing wall condenser 9h, The flue gas outlet of the white-removing heat exchanger 9a is communicated with the atmosphere through the top flue gas outlet of the step condensed water film decontamination module 9, wherein the hot water R outlet of a tower bottom water tank 9l is respectively connected with the inlet of the high-temperature side inlet water R1 of the waste heat user heater 10, the inlet of the external cooling tower inlet water R3 and the system water replenishing pipe of the desulphurization circulating water replenishing water B of the desulphurization tower 7 through a water pump, the outlet of the high-temperature side outlet water R2 of the waste heat user heater 10 is connected with the inlet of the circulating spray device 9f and (or) communicated with the inlet of the external cooling tower return water R4, the low-temperature side inlet water inlet of the waste heat user heater 10 is communicated with the return water main pipe of the hot user return water H0 and (or) communicated with the inlet of the dividing wall condenser 9H, the outlet of the low-temperature side outlet water H1 of the waste heat user heater 10 is communicated with the inlet water of the downstream return water H3, and the outlet of the downstream water heater is communicated with, And (or) the washing spraying device 9c is provided with an inlet of washing solution Na, and the white-removing heat exchanger 9a is respectively provided with an inlet of heating inlet water J2 and an outlet of heating outlet water J1.

The process flow of the flue gas haze removal and white elimination method and system comprises a medium-temperature flue gas heat recovery device 6, the medium-temperature flue gas heat recovery device 6 adopts an extrusion-molded aluminum fin heat exchange tube structure coated with a graphene material, a corrosion-resistant special material metal heat exchanger structure or a fluoroplastic heat exchanger structure, a low-temperature side water inlet of the medium-temperature flue gas heat recovery device 6 is connected with an outlet of heating water outlet J1 of a white elimination heat exchanger 9a, and a low-temperature side water outlet of the medium-temperature flue gas heat recovery device 6 is connected with an inlet of heating water inlet J2 of the white elimination heat exchanger 9 a.

The high-temperature dust collector 2 adopts a bag type dust collector structure made of basalt filter materials. If the high-temperature dust remover 2 is not arranged, a conventional medium-low temperature dust remover 4 is arranged, wherein a flue gas inlet of the conventional medium-low temperature dust remover 4 is communicated with a flue gas outlet of the boiler 2, and a flue gas outlet of the conventional medium-low temperature dust remover 4 is communicated with a flue gas inlet of a desulfurizing tower 7 or a medium-temperature section flue gas heat recoverer 6.

The medium-temperature flue gas heating surface 1a, the medium-temperature flue gas heating surface 1b, the white heat removal heat exchanger 9a and the dividing wall condenser 9h are all of extrusion-molded aluminum fin heat exchange tube structures coated with graphene materials.

The one-way rectifier 9i adopts a rectifying structure which has the functions of deflecting the flue gas flow for multiple times and flushing a water film on the wall surface, intercepting fog drops and impurities in the upward flue gas flow, converging downward for removal, enabling water drops flowing downward from the upper part to conveniently pass through or flush the wall surface to adsorb and remove pollutants in the flue gas, enabling water drops on the upper side and the lower side to flow in one direction, deflecting the flue gas for multiple times and flushing the water drops and then uniformly exhausting the flue gas.

The lower washing heat exchanger 9g and the upper washing heat exchanger 9d both adopt condensation heat exchange materials resistant to strong acid and strong base corrosion and scaling and fouling resistance.

The desulfurizing tower 7 adopts a wet desulfurizing, dry desulfurizing or adsorption desulfurizing structure.

And the inlet washing solution Na of the washing and spraying device 9c adopts a dilute sodium hydroxide solution with the pH value of 7-10.

The utility model discloses carry more particle pollutant especially a large amount of penetrable particulate matters (PM 0.3 and below) and acid gas to current situation boiler flue gas tail feather, belong to one of the main causes of haze, and pollute the problem of neighbouring ground environment, adopt high temperature dust remover to improve denitrification facility efficiency and eliminate its poisoning root cause, adopt step condensation water film scrubbing module to reduce vapor by a wide margin, sulfur dioxide, acid gas such as hydrogen chloride, Filterable Particulate Matter (FPM), can Condense Particulate Matter (CPM) and particulate matter (DPM) in the penetrable particulate matter (EPM), clean high altitude diffusion of discharging fume discharges, fundamentally cuts down by a wide margin or has eliminated the boiler and discharged fume to haze formation and peripheral air environment's substantive adverse effect basically. Meanwhile, waste heat recovery is used as an important driving force for the step haze removal process, so that on one hand, the flue gas releases heat to generate a large amount of condensed water to remove water vapor, and on the other hand, more acidic gas, escaping particulate matters, filtering particulate matters and the like can be absorbed or adsorbed; on the other hand, a part of high-grade waste heat is adopted to reheat the outlet flue gas so as to realize visual whitening elimination, improve the diffusion effect of the outlet flue gas in the atmosphere and effectively reduce the concentration of pollutants in an adjacent airspace; meanwhile, the condensed water washes the lower overflowing wall surface to remove the adhered pollutants, and further absorbs or adsorbs more pollutants through the water film; furthermore, the temperature of the circulating water falling into the water tank at the bottom of the tower is increased, the heat of the circulating water can be transferred to the return water of a downstream hot user through the heat exchanger to realize waste heat utilization, the cooled water is conveyed to the spraying device by the water pump to continue deep recovery of flue gas condensate water and absorption or adsorption of pollutants, and redundant condensate water is discharged and reused as desulfurization water supplement and the like, so that the dual effects of waste heat recovery and pollutant removal are realized, and the waste heat utilization can generate energy-saving benefits, thereby realizing the environment-friendly investment and operation with economic benefits, and having remarkable technical and economic advantages in the fields of deep energy-saving recovery and emission reduction treatment of boiler exhaust smoke.

On the other hand, when the system has a larger heating load requirement in winter, a large amount of water vapor condensation waste heat can be converted into heat recovery heating; however, in the non-heating period, the waste heat utilization benefit can be realized only by searching for downstream heat users such as process water heating and the like, otherwise, when the waste heat cannot be utilized more, the part of the waste heat can be dissipated to the atmosphere only by additionally arranging a cooling tower and the like, but at the moment, a part of water supplement, water pump, fan power consumption and the like are consumed, so that the stepped condensed water film decontamination process is realized to achieve the purposes of deeply reducing smoke pollution emission and visually eliminating the white in summer.

Drawings

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

The parts in fig. 1 are numbered and named as follows.

The system comprises a boiler 1, a medium-temperature flue gas heating surface 1a, a medium-low temperature flue gas heating surface 1B, a high-temperature dust remover 2, a denitration device 3, a conventional medium-low temperature dust remover 4, an induced draft fan 5, a medium-temperature section flue gas heat recoverer 6, a desulfurization tower 7, a desulfurization stock solution pool 7a, a step condensate water film decontamination module 9, a white-removing heat exchanger 9a, a demister 9B, a washing spray device 9c, an upper washing heat exchanger 9D, a washing demister 9e, a circulating spray device 9f, a lower washing heat exchanger 9g, a dividing wall condenser 9H, a one-way rectifier 9i, a washing condensate rain region 9J, a flue gas inlet section 9k, a tower bottom water pool 9l, a waste heat user heater 10, a boiler inlet air A, water supplement B, dust discharge D, hot user return water H0, low-temperature outlet water H1, a dividing wall condenser 9H outlet water H2, inlet water H3, heating outlet water J1, heating inlet water, Ammonia NH3, hot water R, high-temperature side inlet water R1, high-temperature side outlet water R2, cooling tower inlet water R3, cooling tower return water R4, desulfurization tower outlet water S, desulfurization circulating return water SH, desulfurization circulating water supply SG, separation pool pollution discharge SS, high-temperature dust collector inlet flue gas Y1, high-temperature dust collector outlet flue gas Y2, denitration device outlet flue gas Y3, boiler outlet flue gas Y4, desulfurization tower outlet flue gas Y5 and cascade condensed water film decontamination module outlet flue gas Y6.

Detailed Description

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

The embodiment of the present invention is as follows.

The utility model provides a flue gas removes haze and white process systems that disappears based on waste heat drive, adopts the flue gas that comprises a set of flue gas complete component treatment process flow to remove haze and white process systems that disappears, and key equipment in this system includes high temperature dust remover 2, step condensate water film scrubbing module 9 and (or) middle temperature section flue gas heat recovery device 6, its characterized in that: 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-temperature and low-temperature flue gas heating surface 1b, the step condensation water film decontamination module 9 adopts an integrated step heat exchange washing tower structure, the flue gas inlet at the lower part of the tower body is communicated with the flue gas outlet of the desulfurization tower 7, the bottom of the tower body is provided with a tower bottom water tank 9l, the upper part of the tower bottom water tank 9l is provided with a flue gas inlet section 9k, and the flue gas sequentially passes through a washing condensation rain zone 9j, a one-way rectifier 9i, a dividing wall condenser 9h, The flue gas outlet of the white-removing heat exchanger 9a is communicated with the atmosphere through the top flue gas outlet of the step condensed water film decontamination module 9, wherein the hot water R outlet of a tower bottom water tank 9l is respectively connected with the inlet of the high-temperature side inlet water R1 of the waste heat user heater 10, the inlet of the external cooling tower inlet water R3 and the system water replenishing pipe of the desulphurization circulating water replenishing water B of the desulphurization tower 7 through a water pump, the outlet of the high-temperature side outlet water R2 of the waste heat user heater 10 is connected with the inlet of the circulating spray device 9f and (or) communicated with the inlet of the external cooling tower return water R4, the low-temperature side inlet water inlet of the waste heat user heater 10 is communicated with the return water main pipe of the hot user return water H0 and (or) communicated with the inlet of the dividing wall condenser 9H, the outlet of the low-temperature side outlet water H1 of the waste heat user heater 10 is communicated with the inlet water of the downstream return water H3, and the outlet of the downstream water heater is communicated with, And (or) the washing spraying device 9c is provided with an inlet of washing solution Na, and the white-removing heat exchanger 9a is respectively provided with an inlet of heating inlet water J2 and an outlet of heating outlet water J1.

The process flow of the flue gas haze removal and white elimination method and system comprises a medium-temperature flue gas heat recovery device 6, the medium-temperature flue gas heat recovery device 6 adopts an extrusion-molded aluminum fin heat exchange tube structure coated with a graphene material, a corrosion-resistant special material metal heat exchanger structure or a fluoroplastic heat exchanger structure, a low-temperature side water inlet of the medium-temperature flue gas heat recovery device 6 is connected with an outlet of heating water outlet J1 of a white elimination heat exchanger 9a, and a low-temperature side water outlet of the medium-temperature flue gas heat recovery device 6 is connected with an inlet of heating water inlet J2 of the white elimination heat exchanger 9 a.

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

The medium-temperature flue gas heating surface 1a, the medium-temperature flue gas heating surface 1b, the white heat removal heat exchanger 9a and the dividing wall condenser 9h are all of extrusion-molded aluminum fin heat exchange tube structures coated with graphene materials.

The one-way rectifier 9i adopts a rectifying structure which has the functions of deflecting the flue gas flow for multiple times and flushing a water film on the wall surface, intercepting fog drops and impurities in the upward flue gas flow, converging downward for removal, enabling water drops flowing downward from the upper part to conveniently pass through or flush the wall surface to adsorb and remove pollutants in the flue gas, enabling water drops on the upper side and the lower side to flow in one direction, deflecting the flue gas for multiple times and flushing the water drops and then uniformly exhausting the flue gas.

The lower washing heat exchanger 9g and the upper washing heat exchanger 9d both adopt condensation heat exchange materials resistant to strong acid and strong base corrosion and scaling and fouling resistance.

The desulfurizing tower 7 adopts a wet desulfurizing structure.

And the inlet washing solution Na of the washing and spraying device 9c adopts a dilute sodium hydroxide solution with the pH value of 7-10.

The embodiment 1 is suitable for comprehensive treatment of boiler exhaust smoke of a newly-built project, and deep haze removal treatment of industrial kiln or process flue gas of a newly-built or newly-expanded project, but generally, for an existing coal-fired boiler system, a heated surface at the tail of the flue gas, even a denitration device and the like are integrated in a boiler body, a high-temperature dust remover is installed in the boiler body without enough space, or medium-high temperature flue gas is led out of the high-temperature dust remover and then returns to an original flue, so that the direct application is difficult, and the method can be modified according to the following specific embodiment 2.

Embodiment 2 of the present invention is as follows.

If the high-temperature dust remover 2 is not suitable to be arranged due to reasons such as field installation space and the like, a conventional medium-low temperature dust remover 4 can be arranged instead, wherein a flue gas inlet of the conventional medium-low temperature dust remover 4 is communicated with a flue gas outlet of the boiler 1, and a flue gas outlet of the conventional medium-low temperature dust remover 4 is communicated with a flue gas inlet of a desulfurizing tower 7 or a medium-temperature section flue gas heat recoverer 6. Other system processes and features of this embodiment are the same as those of embodiment 1 described above.

Embodiment 3 of the present invention is as follows.

If the existing boiler adopts a dry method, a semi-dry method or an adsorption type desulfurization mode, namely a desulfurization tower 7 in a wet method mode is not arranged, the flue gas outlet of the medium-temperature section flue gas heat recoverer 6 is changed to be communicated with the flue gas inlet of the step condensate water film decontamination module 9. Other system processes and characteristics of the embodiment are the same as those of the embodiment 1, at this time, the cleanliness of the flue gas after dry desulfurization, high-temperature dust removal and high-temperature denitration is very high, and inherent problems of fouling and blocking, efficiency reduction, periodic ash removal and maintenance, corrosion acceleration and the like are solved in various heat exchangers on a flue gas channel, including a medium-low temperature flue gas heating surface 1b and the flue gas side of heat exchange elements such as an existing air preheater of a boiler, a medium-temperature section flue gas heat recoverer 6 and the like.

It should be noted that the utility model provides a carry out the depth of full composition to boiler exhaust gas and administer in order to eliminate the influence factor to haze and surrounding environment pollution to the boiler, and give how to adopt the step to remove the haze mode and realize concrete implementation method, flow and implementation device of above-mentioned purpose, and according to this overall solution can have different concrete implementation measures and different structural concrete implementation devices, the above-mentioned concrete implementation is only one of them, any other similar simple variant implementation ways, for example adopt different heat transfer structures; increasing or reducing a plurality of layers of step treatment measures; or simply adjusting the pipeline connection method, the water inlet and outlet sources and the grading number of the waste heat water system; or the technical mode can be applied to different power equipment smoke exhaust or air exhaust types, and other similar application occasions by the same or similar structures, and the like, and all fall into the protection scope of the utility model.

Claims (9)

1. The utility model provides a flue gas removes haze and white process systems that disappears based on waste heat drive, adopts and administers in order to reduce the vapor in the flue gas by a set of flue gas total composition, the flue gas that the technological process of the evasive particulate matter and filterable particulate matter including nanometer yardstick's soluble salt, acid gas including sulfur dioxide and hydrogen chloride is constituteed removes haze and white process systems that disappears, key equipment in this system includes high temperature dust remover (2), step condensate film scrubbing module (9) and (or) middle temperature section flue gas heat recovery ware (6), its characterized in that: 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 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 a denitration device (3), the flue gas outlet of the denitration device (3) is connected with the flue gas inlet of a medium-temperature flue gas heating surface (1 b), a step condensed water film decontamination module (9) adopts an integrated step heat exchange washing tower structure, the flue gas inlet at the lower part of the tower body is communicated with the flue gas outlet of a desulfurization tower (7), a tower bottom water pool (9 l) is arranged at the bottom of the tower body, a flue gas inlet section (9 k) is arranged at the upper part of the tower bottom water pool (9 l), and the flue gas sequentially passes through a washing and condensing rain area (9 j), a one-way rectifier (9 i, 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 (9B) and a white heat exchanger (9 a), wherein a flue gas outlet of the white heat exchanger (9 a) is communicated with the atmosphere through a flue gas outlet at the top of a step condensed water film decontamination module (9), a hot water outlet (R) of a water pool (9 l) at the bottom of the tower is respectively connected with an inlet of high-temperature side water inlet (R1) of a waste heat user heater (10) through a water pump, is communicated with an inlet of external cooling tower water inlet (R3) and is communicated with a system water replenishing pipe of desulfurization circulating water replenishing water (B) of a desulfurization tower (7), an outlet of high-temperature side water outlet (R2) of a waste heat user heater (10) is connected with an inlet of the circulating spray device (9 f) and/or is communicated with an inlet of external cooling tower (R4) backwater, the low-temperature side water inlet of the waste heat user heater (10) is communicated with a water return main pipe of hot user water return (H0) and/or is communicated with a water inlet of a dividing wall condenser (9H), the outlet of low-temperature side inlet and outlet water (H1) of the waste heat user heater (10) is communicated with the water inlet of inlet water (H3) of a downstream water return heater and/or is communicated with the water outlet of outlet water (H2) of the dividing wall condenser (9H), the washing and spraying device (9 c) is provided with an inlet of washing solution (Na), and the white-removing heat exchanger (9 a) is respectively provided with an inlet for heating the inlet water (J2) and an outlet for heating the outlet water (J1).

2. The waste heat-driven smoke haze removal and white elimination process system as claimed in claim 1, wherein the process flow of the smoke haze removal and white elimination method and system comprises a middle-temperature section smoke heat recoverer (6), the middle-temperature section smoke heat recoverer (6) adopts an extruded aluminum fin heat exchange tube structure coated with graphene materials, a corrosion-resistant special material metal heat exchanger structure or a fluoroplastic heat exchanger structure, a low-temperature side water inlet of the middle-temperature section smoke heat recoverer (6) is connected with an outlet of heated water outlet (J1) of a white elimination heat exchanger (9 a), and a low-temperature side water outlet of the middle-temperature section smoke heat recoverer (6) is connected with an inlet of heated water inlet (J2) of the white elimination heat exchanger (9 a).

3. The flue gas haze removal and white elimination process system based on residual heat driving as claimed in claim 1, characterized in that the high temperature dust collector (2) adopts a bag type dust collector structure made of basalt filter material.

4. The flue gas haze removal and white elimination process system based on waste heat driving of claim 1, wherein the medium-temperature flue gas heating surface (1 a), the medium-low temperature flue gas heating surface (1 b), the white elimination heat exchanger (9 a) and the partition wall condenser (9 h) are all of an extruded aluminum fin heat exchange tube structure coated with a graphene material.

5. The flue gas haze removal and white elimination process system based on waste heat driving as claimed in claim 1, wherein the one-way rectifier (9 i) adopts a rectification structure which has the functions of deflecting flue gas flow for multiple times and flushing water films on the wall surface, intercepting fog drops and impurities in upward flue gas flow and converging downward for drainage, enabling water drops flowing downward from the upper part to conveniently pass through or flush the wall surface to adsorb and drain pollutants in the flue gas, enabling water drops on the upper side and the lower side to flow in one direction, and uniformly exhausting air after being deflected and flushed with the flue gas for multiple times.

6. The waste heat-driven flue gas haze removal and white elimination process system as claimed in claim 1, wherein if the high temperature dust collector (2) is not provided, a conventional medium and low temperature dust collector (4) is provided, wherein a flue gas inlet of the conventional medium and low temperature dust collector (4) is communicated with a flue gas outlet of the boiler (1), and a flue gas outlet of the conventional medium and low temperature dust collector (4) is communicated with a flue gas inlet of a desulfurizing tower (7) or a medium temperature section flue gas heat recoverer (6).

7. The flue gas haze removal and white elimination process system based on residual heat driving as claimed in claim 1, wherein the lower washing heat exchanger (9 g) and the upper washing heat exchanger (9 d) both adopt condensation heat exchange materials resistant to strong acid and strong base corrosion and scaling and fouling resistance.

8. The waste heat-driven flue gas haze and white removal process system as claimed in claim 1, wherein the desulfurizing tower (7) adopts a wet desulfurizing, dry desulfurizing or adsorptive desulfurizing structure.

9. The flue gas haze removal and white elimination process system based on residual heat driving as claimed in claim 1, wherein the inlet washing solution (Na) of the washing and spraying device (9 c) adopts a dilute sodium hydroxide solution with a pH value of 7-10.

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