CN201807287U - Flue gas demercuration system based on photochemistry advanced oxidation - Google Patents
Flue gas demercuration system based on photochemistry advanced oxidation Download PDFInfo
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- CN201807287U CN201807287U CN2010205477550U CN201020547755U CN201807287U CN 201807287 U CN201807287 U CN 201807287U CN 2010205477550 U CN2010205477550 U CN 2010205477550U CN 201020547755 U CN201020547755 U CN 201020547755U CN 201807287 U CN201807287 U CN 201807287U
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Abstract
A flue gas demercuration system based on photochemistry advanced oxidation is provided with a combustion and discharge system which comprises a combustor, an electrostatic precipitator, a heat exchanger, a spray tower, a liquid-adding tower, a chimney and a separating column. The flue gas generated by the combustor is guided into the heat exchanger in order to cool after being guided to the electrostatic precipitator for the purpose of removing particulate matters, and then the cooled flue gas is guided into the spray tower. An ultraviolet tube is arranged in the spray tower. The hydrogen dioxide solution from the liquid-adding tower is extracted by a circulating pump and then is sprayed into the spray tower through an atomizing nozzle, so as to decompose the hydrogen peroxide after being excited by the ultraviolet light for the purpose of generating hydroxyl free radicals (.OH) having strong oxidability and having gas-liquid absorbing reaction with the flue gas in the spray tower. The HgO in the flue gas is oxidized and removed. The flue gas after being absorbed and washed is guided into the chimney for discharging from the top of the spray tower. The HgO generated in the spray tower is oxidized into soluble Hg2<+> in a solution. The solution with soluble Hg2<+> is sucked in the separating column by the circulating pump and reacts with the added Na2S solution to generate HgS, so as to realize capturing and recovery of Hg2<+> and flue gas demercuration.
Description
Technical field
The utility model relates to the mercury emissions pollution control technology in the flue gases such as comprising boiler of power plant, Industrial Stoves and incinerator, relates in particular to a kind of flue gas demercuration system based on the effect of photochemistry advanced oxidation.
Background technology
Mercury is a kind of severe toxicity, high volatile volatile, is easy to deposit and traces of heavy metals element that hysteresis is long in vivo, and health and ecological environment are all had great harm.Studies show that, thermal power generation, waste incineration and with the fossil fuel be the industrial process such as cement, metallurgy of power be artificial mercury pollution important discharging in a steady stream, the coal combustion process that derives from the thermal power plant about 70% is wherein arranged again.China is the big consumption of coal of the first in the world state, and the ratio of coal is up to 75% in the energy resource structure, and this general layout does not also have big change in long from now on a period of time.Therefore, how effectively to control mercury emissions in the coal-fired flue-gas and become one of vital task that the Chinese government faces.
At present, domestic and international modal flue gas demercuration technology mainly comprises active carbon adsorption, wet desulphurization (WFGD) associating washing method and SCR (SCR) catalytic oxidation etc.Active carbon adsorption is at present ripe demercuration technology, but it is big to have an active carbon consumption, and the high deficiency of regeneration energy consumption also is difficult to obtain large-scale application at present.Wet desulphurization (WFGD) associating demercuration method can remove the divalence mercury (Hg about 80-95%
2+), but to nonvalent mercury (Hg
0) removal efficiency very low.SCR (SCR) catalytic oxidation can be with Hg
0Catalytic oxidation is Hg
2+, remove in conjunction with wet scrubbing then, but also be in the experimental study stage at present.Therefore, the effective flue gas demercuration technology of active development remains one of vital task of this field technology personnel.
The wet flue gas demercuration has advantages such as the simple and cost of investment of technological process is low, but the research of traditional wet method hydrargyrum-removing technology makes slow progress always, and its main cause just is that the mercury in the flue gas mainly exists with two kinds of forms: Hg
0And Hg
2+Compound.Hg
0Have characteristics such as fusing point is low, equilibrium vapor pressure is high, not soluble in water, according to the difference of ature of coal, one accounts for flue gas altogether about the 40-80% of content.By double-film theory as can be known, Hg
0Must at first change liquid phase over to through mass transfer and diffusion process, chemical reaction could take place then be fixed in the absorption liquid Hg by gaseous state
0The resistance that the characteristic of indissoluble makes its liquid phase absorb increases greatly, only is difficult to significantly improve Hg by regulation and control pH and method of temperature
0In the solubility of liquid phase, this characteristic has caused traditional wet method demercuration technology ubiquity removal efficiency low, and problems such as energy consumption height have hindered its industrial applications.Therefore, exploitation is a kind of can be with Hg
0The new technology that is converted into easy molten form fast is one of key issue of wet flue gas demercuration technology.
Summary of the invention
The utility model discloses a kind of flue gas demercuration system, utilize the ultraviolet excitation decomposition of hydrogen peroxide, and produce the nonvalent mercury (Hg in hydroxyl radical free radical (OH) the oxidation removal flue gas with strong oxidizing property based on the effect of photochemistry advanced oxidation
0), Hg
0At first be oxidized to soluble divalence mercury (Hg
2+) be fixed in the solution, by adding Na to knockout tower
2S solution generates the HgS of indissoluble to Hg
2+Catch recovery, finally reach the flue gas demercuration purpose.
For realizing above purpose, the embodiment that the utility model adopts is: a kind of flue gas demercuration system based on the effect of photochemistry advanced oxidation, it is characterized in that: be provided with burner, electrostatic precipitator, heat exchanger, spray column, add the liquid tower, burning and exhaust system that chimney and knockout tower constitute, the flue gas that burner produces feeds electrostatic precipitator and removes and feed the heat exchanger back that cools behind the flue gas particles and feed spray column, be provided with ultraviolet lamp tube in the spray column, extract by circulating pump and spray in the spray column through the ultraviolet excitation decomposition of hydrogen peroxide from the hydrogenperoxide steam generator that adds in the liquid tower by atomizer, the hydroxyl radical free radical (OH) that produces strong oxidizing property contacts the back with flue gas Gas-Liquid Absorption reaction, the Hg in the oxidation removal flue gas takes place in spray column
0, the flue gas after absorbing washing feeds smoke stack emission, the Hg that generates in the spray column from the spray column top
0Be oxidized to soluble Hg
2+Be fixed in the solution, by the second circulating pump suction knockout tower and with add Na
2The solution of S generates the HgS of indissoluble to Hg
2+Catch to reclaim and realize flue gas demercuration.
The section H g that generates in the described spray column
2+It is recycling to improve Hg in the spray column that solution also adds the liquid tower through the 3rd circulating pump suction again
2+The concentration of solution, the volume of the circulation solution of extraction account for the ratio of total liquor capacity at 20-60%.
Described ultraviolet wavelength scope is 120nm-360nm, ultraviolet ray intensity need remain on 5W/L-65W/L, before the W/L of unit is meant and does not install before the uviol lamp in the spray column and do not feed flue gas and solution herein, the ultraviolet radiation power of the unit volume of whole spray column void tower, ultraviolet lamp tube is provided with the spray column bottom surface is vertical.
When many ultraviolet lamp tubes are set, many ultraviolet lamp tubes are the concentric circles setting on the spray column bottom surface, distance is identical between the neighboring concentric circle, value is 2cm-15cm, many ultraviolet lamp tubes are distributed on the circumference of different-diameter, and along same diameter line setting, the central angle between each adjacent two diameter line is identical, value is the 15-50 degree, and circle centre position is provided with ultraviolet lamp tube; Atomizer is arranged on the spray column top and on the concentric circles between the ultraviolet lamp tube concentric circles, is arranged on the diameter line in the ultraviolet lamp tube central angle.
The span of the response parameter of flue gas demercuration is as follows: electrostatic precipitator removes the flue gas particles of particle diameter greater than 2.5 μ m; Flue gas after heat exchanger cools to 5-60 ℃ of feeding spray column; Spray into the pH value 0.5-6.5 of the hydrogenperoxide steam generator in the spray column; The hydrogenperoxide steam generator dosage is 0.1mol/L-1.5mol/L; The concentration of hydrogenperoxide steam generator is 0.1mol/L-1.5mol/L; Atomizer to the atomizing of hydrogenperoxide steam generator after particle diameter 0.05mm-0.8mm, liquid-gas ratio 5L/m in the spray column
3-35L/m
3Add Na
2The flow-control of S Hg in entering knockout tower
2+The 10-40% of solution total flow, the vulcanized sodium molar concentration of interpolation is calculated as follows:
In the formula, n (Na
2S) for adding the molar concentration of vulcanized sodium, mol/L; η
Hg0Be Hg
0Removal efficiency, %; C
In(Hg
0) be Hg in the flue gas
0The inlet initial concentration, ppm; Q
FBe flue gas total flow, m
3/ h; M
Hg0Be Hg
0Molal weight, g/mol; The running time of t-system, h.
Advantage of the present utility model and remarkable result: compare with the wet oxidation demercuration technology that simple hydrogen peroxide, ozone, potassium permanganate and clorox etc. are traditional:
(1) because OH has the redox potential (2.87eV that is only second to fluorine) up to 2.80eV, have extremely strong oxidability, can be fast with Hg
0Be oxidized to the Hg that is soluble in absorption liquid
2+Thereby, increased Hg greatly
0By the mass transfer force of gas phase, improved Hg to liquid phase
0Absorption rate, overcome the bottleneck of conventional wet hydrargyrum-removing technology effectively.
(2) because OH and hydrogen peroxide are clean environmental protection oxidant, be fixed in the Hg in the liquid phase
2+Through Na
2But recycling after S is fixing, whole subtractive process non-secondary pollution, and conventional oxidation methods such as potassium permanganate and clorox can produce complicated accessory substance, bring very big difficulty to post processing;
(3) in view of strong oxidizing property and the non-selectivity of OH, this technology has and removes multiple common vapor phase contaminants simultaneously, such as oxysulfide, the potentiality of nitrogen oxide and volatile organic contaminant, along with people's improving constantly to environmental requirement, these potentiality and advantage will be highlighted gradually, and traditional wet method hydrargyrum-removing technology does not then have the multicontaminated potentiality of further integrated treatment.
Description of drawings
Fig. 1 is the utility model system construction drawing;
Fig. 2. be the mounting arrangements cross-sectional view of the utility model system medium ultraviolet lamp;
Fig. 3. be the mounting arrangements cross-sectional view of atomizer in the utility model system.
The specific embodiment
Referring to Fig. 1, the flue gas that burner 1 produces feeds electrostatic precipitator 2 and removes and feed heat exchanger 3 back that cools behind the flue gas particles and feed spray column 4, be provided with ultraviolet lamp tube 6 in the spray column 4, extract by circulating pump 7 and spray in the spray column 4 through the ultraviolet excitation decomposition of hydrogen peroxide from the hydrogenperoxide steam generator that adds in the liquid tower 10 by atomizer 5, the hydroxyl radical free radical (OH) that produces strong oxidizing property contacts the back with flue gas Gas-Liquid Absorption reaction, the nonvalent mercury Hg in the oxidation removal flue gas takes place in spray column 4
0, Hg
0At first be oxidized to soluble divalence mercury Hg
2+Be fixed in the solution, by adding Na to knockout tower 11
2S solution generates the HgS of indissoluble to Hg
2+Catch recovery, after precipitate and separate, can realize the recycling of mercury, finally reach the flue gas demercuration purpose.
The reaction mechanism of hydrogen peroxide under UV-irradiation:
(1) hydrogen peroxide can decompose release hydroxyl radical free radical (OH) under UV-irradiation:
H
2O
2+hv→2·OH (1)
(2) Hg
0Be oxidized to Hg
2+:
Hg
0+·OH→HgO+·H (2)
Hg
0+2·OH→Hg(OH)
2 (3)
Hg
0+H
2O
2→HgO+H
2O (4)
Because the flue gas that burner 1 flows out contains a large amount of particles,, cause penetrance, the irradiation distance of ultraviolet light in the spray column 4 to descend significantly, and then reduced the efficiency of light energy utilization if can cause the ultraviolet reflection of light after directly entering spray column 4.Therefore, spray column 4 must place after the electrostatic precipitator 2, promptly has only through the spray column 4 of being allowed for access of the flue gas behind the electrostatic precipitation and accepts washing and remove, and particle diameter must remove greater than the particle of 2.5 μ m in the flue gas.
Through after the electrostatic precipitation, because the temperature of flue gas is usually between 200-400 ℃, flue-gas temperature is too high will to cause the solution temperatures in the spray column 4 to increase at flue gas.Along with the increase of solution temperature, the solubility of gas in solution will descend greatly, and the removal efficiency of pollutant also can decrease.In addition, along with the increase of temperature, hydrogen peroxide will selfdecomposition be water and oxygen, rather than is decomposed into hydroxyl radical free radical, and this will make the effective rate of utilization of hydrogen peroxide reduce significantly, finally increase application cost.Therefore, flow out before electrostatic precipitator 2 enters spray column 4 at flue gas, flue gas also needs to participate in the Gas-Liquid Absorption reaction in the spray column 4 for the treatment of to be allowed for access when flue-gas temperature is reduced to 5-60 ℃ through the cooling of over-heat-exchanger 3.
Uviol lamp 6 is with quartz socket tube, adopts immersion to install, and uviol lamp 6 mainly is by the hydrogenperoxide steam generator radiation ultraviolet light around being looped around, and produces hydroxyl radical free radical.In addition, by the light radiation principle as can be known, luminous intensity maximum when the light vertical radiation arrives the surface, thereby in order to maximally utilise ultraviolet luminous energy, improve light radiation intensity, uviol lamp 6 need keep vertical with spray column 4 lower surface, and necessary keeping parallelism between the uviol lamp 6, to reach the maximum using of luminous energy; After in the spray column 4 uviol lamp 6 being installed, the flow of flue gas resistance will increase in the tower, thereby has increased the operating load of air-introduced machine.Therefore, the layout density of uviol lamp 6 in spray column 4 can not be too little, if but uviol lamp 6 arranges that density is too big, then can cause the volume of spray column 4 sharply to increase, and the floor space of whole system also can increase thereupon, causes application cost to increase; In addition, uviol lamp 6 is arranged the too little ultraviolet radiation intensity that also can reduce unit volume solution of density, pollutes the thing removal effect and worsens.Therefore, spacing a between the uviol lamp 6 and central angle b should not too greatly also should not be too little, the optimum range of uviol lamp spacing and central angle is respectively 2cm-15cm and 15-50 degree, under the condition that satisfies above spacing and central angle, spacing a between the uviol lamp 6 also must keep identical (Fig. 2) with central angle b, if certainly will cause ultraviolet radiation inhomogeneous of solution in the spray column 4 if spacing and central angle are unequal, and then cause the photochemical reaction speed in the spray column 4 to differ greatly, be unfavorable for the effective utilization with luminous energy of removing of pollutant.Uviol lamp 6 irradiation intensities are related to the size of quantum yield, and then have influence on the productive rate of hydroxyl radical free radical.Too little then being difficult to of ultraviolet light irradiation intensity produces enough hydroxyl radical free radical oxidation removal pollutants, but ultraviolet light irradiation intensity is when too big, and the energy consumption of system then significantly increases, and causes application cost to increase considerably.Therefore, ultraviolet ray intensity need remain on 5W/L-65W/L, wherein the W/L of unit be meant spray column uviol lamp is not installed and do not feed reaction solution and flue gas before, the needed ultraviolet radiation power of unit volume (perhaps radiation intensity) when spray column is void tower.The selection of ultraviolet wavelength has significant effects for photochemical reaction process, ultraviolet wavelength is related to the effective propagation distance of ultraviolet light and the activation degree of photon, and then is related to the pollutant disposal ability of unit power ultraviolet light and the excitation energy size of unit photon.Ultraviolet wavelength more in short-term, although this moment, the photon excitation of ultraviolet light can become big, but the propagation distance of ultraviolet light is shorter, the pollutant disposal ability that shows as the unit power ultraviolet light is lower, be difficult to practical application, but when ultraviolet wavelength is longer, although the propagation distance of ultraviolet light will increase, but this moment, the excitation energy of ultraviolet light photons reduced greatly, cause ultraviolet light photons to excite decomposition of hydrogen peroxide to discharge the energy wretched insufficiency of hydroxyl radical free radical, finally cause the removal efficiency of pollutant to be difficult to meet the demands.Therefore, the ultraviolet light wavelength should remain in the 120nm-360nm scope;
Hydrogenperoxide steam generator is when the top of spray column 4 sprays into, in order to realize best gas-liquid mass transfer condition, reduce the resistance to mass tranfer of gas-liquid reaction process, hydrogenperoxide steam generator was realized atomizing fully before spraying into spray column 4, to reach enough big gas-liquid contact area as far as possible.Therefore, before hydrogen peroxide sprays into spray column 4, need brute force atomizing, be sprayed into spray column 4, could fully contact concurrent angry liquid absorption reaction with flue gas through the droplet after the atomizing through atomizer 5; In addition, be difficult to guarantee enough gas-liquid contacts area, too little operating load and the energy consumption that then increases circulating pump 7 if the size droplet diameter after the atomizing is too big.Therefore, the atomizing particle size of hydrogenperoxide steam generator is unsuitable excessive also unsuitable too small, need remain in the 0.05mm-0.8mm scope, and atomizer 5 must be installed on the concentric circles between the uviol lamp 6 when mounted simultaneously.(A among Fig. 3, B, C point), the quantity that needs on the concentric circles atomizer is installed then needs to decide according to the model and the size of selected atomizer..
Hydrogen peroxide is as the releasing agent of hydroxyl radical free radical, if dosage is too little, then the hydroxyl radical free radical quantity of Sheng Chenging very little, be not enough to abundant oxidation removal pollutant, but when the dosage of hydrogen peroxide is too big, hydrogen peroxide also can cause some side reactions from consuming a large amount of hydroxyl radical free radicals, causes removal efficiency to descend on the contrary, and the hydrogen peroxide dosage also can bring the too high problem of application cost too greatly.Therefore, the dosage of hydrogen peroxide should remain on 0.1mol/L-1.5mol/L, and the valid density of hydrogenperoxide steam generator is that 0.05mol/L-2.5mol/L hydrogenperoxide steam generator dosage is 0.1mol/L-1.5mol/L; The concentration of hydrogenperoxide steam generator is 0.1mol/L-1.5mol/L.
Liquid-gas ratio is a very crucial parameter in the Gas-Liquid Absorption course of reaction, is related to the removal efficiency and the operating cost of system.When liquid-gas ratio too hour, pollutant can't obtain sufficient gas-liquid contact reaction, cause the removal efficiency of pollutant to descend, but when liquid-gas ratio is too big, the volume of whole system will significantly increase, the operating load of circulating pump (7) and energy consumption also cause the volume of spray column 4 sharply to increase, and the floor space of whole system also can increase thereupon, cause application cost to increase; In addition, uviol lamp 6 is arranged the too little ultraviolet radiation intensity that also can reduce unit volume solution of density, pollutes the thing removal effect and worsens.Therefore, spacing a between the uviol lamp 6 and central angle b should not too greatly also should not be too little, the optimum range of uviol lamp spacing and central angle is respectively 2cm-20cm and 10-45 degree, under the condition that satisfies above spacing and central angle, spacing a between the uviol lamp 6 also must keep identical (Fig. 2) with central angle b, if certainly will cause ultraviolet radiation inhomogeneous of solution in the spray column 4 if spacing and central angle are unequal, and then cause the photochemical reaction speed in the spray column 4 to differ greatly, be unfavorable for the effective utilization with luminous energy of removing of pollutant.Uviol lamp 6 irradiation intensities are related to the size of quantum yield, and then have influence on the productive rate of hydroxyl radical free radical.Too little then being difficult to of ultraviolet light irradiation intensity produces enough hydroxyl radical free radical oxidation removal pollutants, but ultraviolet light irradiation intensity is when too big, and the energy consumption of system then significantly increases, and causes application cost to increase considerably.Therefore, ultraviolet ray intensity need remain on 5W/L-80W/L, wherein the W/L of unit be meant spray column uviol lamp is not installed and do not feed reaction solution and flue gas before, the needed ultraviolet radiation power of unit volume (perhaps radiation intensity) when spray column is void tower.The selection of ultraviolet wavelength has significant effects for photochemical reaction process, ultraviolet wavelength is related to the effective propagation distance of ultraviolet light and the activation degree of photon, and then is related to the pollutant disposal ability of unit power ultraviolet light and the excitation energy size of unit photon.Ultraviolet wavelength more in short-term, although this moment, the photon excitation of ultraviolet light can become big, but the propagation distance of ultraviolet light is shorter, the pollutant disposal ability that shows as the unit power ultraviolet light is lower, be difficult to practical application, but when ultraviolet wavelength is longer, although the propagation distance of ultraviolet light will increase, but this moment, the excitation energy of ultraviolet light photons reduced greatly, cause ultraviolet light photons to excite decomposition of hydrogen peroxide to discharge the energy wretched insufficiency of hydroxyl radical free radical, finally cause the removal efficiency of pollutant to be difficult to meet the demands.Therefore, the ultraviolet light wavelength should remain in the 120nm-360nm scope;
Hydrogenperoxide steam generator is when the top of spray column 4 sprays into, in order to realize best gas-liquid mass transfer condition, reduce the resistance to mass tranfer of gas-liquid reaction process, hydrogenperoxide steam generator was realized atomizing fully before spraying into spray column 4, to reach enough big gas-liquid contact area as far as possible.Therefore, before hydrogen peroxide sprays into spray column 4, need brute force atomizing, be sprayed into spray column 4, could fully contact concurrent angry liquid absorption reaction with flue gas through the droplet after the atomizing through atomizer 5; In addition, be difficult to guarantee enough gas-liquid contacts area, too little operating load and the energy consumption that then increases circulating pump 7 if the size droplet diameter after the atomizing is too big.Therefore, the atomizing particle size of hydrogenperoxide steam generator is unsuitable excessive also unsuitable too small, need remain in the 0.01mm-0.5mm scope, and atomizer 5 must be installed on the concentric circles between the uviol lamp 6 when mounted simultaneously.(A among Fig. 3, B is on the C line), the quantity that needs on the concentric circles atomizer is installed then needs to decide according to the model and the size of selected atomizer..
Hydrogen peroxide is as the releasing agent of hydroxyl radical free radical, if dosage is too little, then the hydroxyl radical free radical quantity of Sheng Chenging very little, be not enough to abundant oxidation removal pollutant, but when the dosage of hydrogen peroxide is too big, hydrogen peroxide also can cause some side reactions from consuming a large amount of hydroxyl radical free radicals, causes removal efficiency to descend on the contrary, and the hydrogen peroxide dosage also can bring the too high problem of application cost too greatly.Therefore, the dosage of hydrogen peroxide should remain on 0.05mol/L-2.5mol/L.The valid density of hydrogenperoxide steam generator is 0.05mol/L-2.5mol/L
Liquid-gas ratio is a very crucial parameter in the Gas-Liquid Absorption course of reaction, is related to the removal efficiency and the operating cost of system.When liquid-gas ratio too hour, pollutant can't obtain sufficient gas-liquid contact reaction, cause the removal efficiency of pollutant to descend, but when liquid-gas ratio is too big, the volume of whole system will significantly increase, the operating load and the energy consumption of circulating pump (7) also will increase, and finally cause system operation cost to increase greatly.Therefore, liquid-gas ratio remains on 5L/m in the spray column
3-35L/m
3In the scope.
The pH value of hydrogenperoxide steam generator also is a very important parameter, and when the pH value of solution value was too low, the absorption equilibrium of whole absorption process will be moved to the left, and causes the Gas-Liquid Absorption reaction fully not carry out, and then influences removal efficiency.But when the pH value of solution value was too high, because hydrogen peroxide has the characteristic of hydrolysis, the hydrolysate hydrogen peroxide was a kind of very effectively hydroxyl radical free radical aggressive agent with ion, can all obviously reduce the concentration of hydroxyl radical free radical.In addition, the too high hydrolysis that will strengthen hydrogen peroxide of pH value of solution value causes the selfdecomposition speed of hydrogen peroxide to increase, and increases the hydrogen peroxide consumption amount the most greatly, has increased the practical application cost.Therefore, pH value of solution should remain between the 0.5-6.5;
The product of subtractive process is Hg
2+Solution considers that the recycling problem of product is crucial.If Hg
2+Solution concentration is too little, then will make the water consumption of course of reaction increase.Simultaneously, Hg
2+The too little post processing amount of product that also can make of solution concentration increases, and certainly will also can cause the post processing cost of product to increase.Therefore, system need design product part EGR, i.e. Hg
2+Solution partly is returned and continues in the spray column 4 to participate in the Gas-Liquid Absorption reaction, and only part is drawn into knockout tower 11 and accepts post processing, so both can guarantee Hg
2+The concentration of solution, can guarantee that again the post processing cost is unlikely to too high, but the circulation fluid that extracts accounts for the ratio of total solution should not be too high, otherwise can influence the removal efficiency and the security of system, should be strict controlled in and remain between the 20-60% so the volume of the circulation solution that should extract accounts for the ratio of total liquor capacity;
Product Hg
2+Solution can be by adding Na through after the post processing
2The method of S generates HgS, but after precipitate and separate, realize the resource resource, can guarantee that like this entire reaction course do not have secondary emission, product can also be converted into economic benefit, realize the low target that reduces discharging of real high-efficiency low-pollution, but the vulcanized sodium that adds needs strict concentration and traffic requirement, and vulcanized sodium adds the excessive solution-treated amount that will certainly cause of flow and also increases, and the too little interior chemical reaction of knockout tower that then can cause is inhomogeneous.Therefore, flow-control Hg in entering knockout tower of suggestion vulcanized sodium
2+The 10-40% of solution total flow.In addition, if vulcanized sodium concentration is too high, the vulcanized sodium that does not have enough time to participate in reacting will be entrained in the product and emit, and causes secondary pollution, then can not fully effectively absorb the Hg in the fixed solution very little
2+Therefore, the vulcanized sodium molar concentration of interpolation (international unit: mol/L) computational methods are as follows:
In the formula, n (Na
2S) for adding the molar concentration of vulcanized sodium, mol/L; η
Hg0Be Hg
0Removal efficiency, %; C
In(Hg
0) be Hg in the flue gas
0The inlet initial concentration, ppm; Q
FBe flue gas total flow, m
3/ h; M
Hg0Be Hg
0Molal weight, g/mol; The running time of t-system, h.
Embodiment 2.
Embodiment 3.
By implementing 1,2,3 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single ultraviolet wavelength that changes, other parameter all remains unchanged.Find out that by the result ultraviolet light is obtained best removal efficiency at the 253.7nm place.
Embodiment 4.
Embodiment 5.
By implementing 1,4,5 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single concentration of hydrogen peroxide that changes, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient increases along with the increase of concentration of hydrogen peroxide, but in order to keep lower application cost, it is too high that the concentration of hydrogen peroxide also should not be established, and need remain in the 0.5-1.5mol/L scope.
Embodiment 6.
Embodiment 7.
By implementing 1,6,7 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single solution temperature that changes, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient descends along with the increase of solution temperature.Therefore, solution temperature should keep a relatively low value, but the solution temperature setting only then can cause the heat exchanger cooling cost to increase, thereby solution temperature also needs to keep 25 ℃ of optimum values.
Embodiment 8.
Embodiment 9.
By implementing 1,8,9 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single Hg that changes
0Concentration, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient is along with Hg
0Concentration increase and descend.Therefore, Hg
0Concentration value should keep in the optimum range Hg
0Too low this technology scope of application that then makes of concentration narrow down Hg
0The too high removal efficiency that then causes of concentration do not reach environmental requirement, should be set in 5ug/m
3-200ug/m
3In the scope.
Embodiment 11.
By implementing 1,10,11 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single pH value that changes solution, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient increases along with the increase of pH value of solution value, but the too high selfdecomposition rate of hydrogen peroxide that then can cause of pH value of solution value sharply rises, and finally causes application cost to increase.Therefore, the pH value of solution value should be set between the 0.5-6.5;
Embodiment 13.
By implementing 1,14,15 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: single liquid-gas ratio that changes solution, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient increases along with the increase of liquid-gas ratio, but the too high reaction system that then can cause of liquid-gas ratio is bulky, finally causes application cost to increase greatly.Therefore, the value of liquid-gas ratio should be set between the 5-35.
Embodiment 14.
Embodiment 15.
By implementing 1,14,15 as can be seen, form upper part content is an operating parameter, and the bottom is divided into the situation of change of pollutant removing efficient.Concrete method of operating is: UV intensity, other parameter all remains unchanged.By the result as can be seen, pollutant removing efficient increases along with the increase of UV intensity, but the too high energy consumption that then can cause of UV intensity is excessive, finally causes application cost to increase greatly.Therefore, the UV intensity level should be set between the 5-65W.
The most preferred embodiment parameter:
In conjunction with on-the-spot actual conditions, and under the prerequisite of the removal efficiency of taking all factors into consideration pollutant and application cost, the present invention can obtain good demercuration effect according to the most preferred embodiment parameter, removal efficiency can reach 96.8%, especially realizing on the basis that pollutant efficiently removes, but product is recycling also, non-secondary pollution.
Claims (4)
1. flue gas demercuration system based on the effect of photochemistry advanced oxidation, it is characterized in that: be provided with burner, electrostatic precipitator, heat exchanger, spray column, add the liquid tower, burning and exhaust system that chimney and knockout tower constitute, the flue gas that burner produces feeds electrostatic precipitator through pipeline, and pipeline feeds spray column after pipeline feeds heat exchanger, be provided with ultraviolet lamp tube in the spray column, extract by circulating pump and spray in the spray column from the hydrogenperoxide steam generator that adds in the liquid tower by atomizer, flue gas feeds smoke stack emission from the spray column top through pipeline, and product is realized flue gas demercuration by the second circulating pump suction knockout tower and with the Na2S solution reaction that adds in the spray column.
2. according to the described flue gas demercuration system of claim 1 based on the effect of photochemistry advanced oxidation, it is characterized in that: product also adds the liquid tower through the 3rd circulating pump suction again in the spray column, and the volume of the circulation solution of extraction accounts for the ratio of total liquor capacity at 20-60%.
3. according to claim 1 or 2 described flue gas demercuration systems based on the effect of photochemistry advanced oxidation, it is characterized in that: the ultraviolet wavelength scope is 120nm-360nm, ultraviolet ray intensity need remain on 5W/L-65W/L, before the W/L of unit is meant and does not install before the uviol lamp in the spray column and do not feed flue gas and solution herein, the ultraviolet radiation power of the unit volume of whole spray column void tower, ultraviolet lamp tube is provided with the spray column bottom surface is vertical.
4. according to the described flue gas demercuration system of claim 3 based on the effect of photochemistry advanced oxidation, it is characterized in that: when many ultraviolet lamp tubes are set, many ultraviolet lamp tubes are the concentric circles setting on the spray column bottom surface, distance is identical between the neighboring concentric circle, and value is 2cm-15cm, and many ultraviolet lamp tubes are distributed on the circumference of different-diameter, along same diameter line setting, central angle between each adjacent two diameter line is identical, and value is the 15-50 degree, and circle centre position is provided with ultraviolet lamp tube; Atomizer is arranged on the spray column top and on the concentric circles between the ultraviolet lamp tube concentric circles, is arranged on the diameter line in the ultraviolet lamp tube central angle.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103111182A (en) * | 2011-11-17 | 2013-05-22 | 范庆峰 | Technology for removing mercury through strong oxidization of coal-fired power plant flue gas |
| CN103691280A (en) * | 2013-12-13 | 2014-04-02 | 江苏大学 | Method and system for removing flue gas mercury based on ultrasonic excitation of sodium persulfate |
| CN104815554A (en) * | 2015-04-21 | 2015-08-05 | 南京朗洁环保科技有限公司 | Method for removing mercury in flue gas by exciting ozone/peroxides through optical radiation synergistic catalyst |
| CN107754536A (en) * | 2017-11-23 | 2018-03-06 | 尹风玲 | A kind of thermal power generation emission-control equipment |
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2010
- 2010-09-29 CN CN2010205477550U patent/CN201807287U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103111182A (en) * | 2011-11-17 | 2013-05-22 | 范庆峰 | Technology for removing mercury through strong oxidization of coal-fired power plant flue gas |
| CN103691280A (en) * | 2013-12-13 | 2014-04-02 | 江苏大学 | Method and system for removing flue gas mercury based on ultrasonic excitation of sodium persulfate |
| CN103691280B (en) * | 2013-12-13 | 2016-03-02 | 江苏大学 | A kind of method and system removing gas mercury based on ultrasonic excitation sodium peroxydisulfate |
| CN104815554A (en) * | 2015-04-21 | 2015-08-05 | 南京朗洁环保科技有限公司 | Method for removing mercury in flue gas by exciting ozone/peroxides through optical radiation synergistic catalyst |
| CN107754536A (en) * | 2017-11-23 | 2018-03-06 | 尹风玲 | A kind of thermal power generation emission-control equipment |
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