Background technology
Sulfur dioxide is the main pollution factor in atmosphere pollution, and the discharge of sulfur dioxide can cause acid rain to cause acidifying and corrosion to water body, crops, environment, building etc., causes huge economic loss.The high speed development of the industries such as China's iron and steel, metallurgy, nonferrous smelting, chemical industry, bring serious sulfur dioxide pollution, carrying capacity of environment is difficult to bear, and the discharge standard of every profession and trade tightened step by step in recent years, bring restriction to the development of every profession and trade, the degree of depth of sulfur dioxide reduces discharging extremely urgent.
Existing sulfur removal technology is of a great variety, all have some limitations, its subject matter adopts a certain sulfur removal technology technology effectively can not realize the efficient degree of depth to reduce discharging, can not ensure the requirement of the national standard that every profession and trade is up-to-date and regional discharge standard, and single sulfur removal technology well can not ensure economy.
Existing ammonia desulfurizing process flow process, adopts single-stage, two-stage or thtee-stage shiplock sulfur removal technology more.Its basic procedure is: sulfur-containing tail gas reaches after technological requirement through pretreatment, first enter successively in one-level (or two-stage, three grades) absorption tower, ammonium sulfite and ammonium sulfate is generated through ammonia spray sulfur dioxide absorption, the concentration levels of apparent absorption circulation slip, open circuit discharge unit ammonium sulfite or ammonium sulfate slurry, obtain ammonium sulfite or byproduct of ammonium sulfate through evaporation and concentration, crystallization, separation, separating liquid returns configuration ammonia circulation and uses.Sulfur-containing tail gas after one-level (or two-stage, three grades) absorbs, the general 70-300mg/Nm of sulfur dioxide concentration
3, emptying through chimney.In current sulfuric acid industry pollutant emission standard GB26132-2010 by sulfur dioxide (SO2) emissions limit value by 960mg/Nm
3be adjusted to general regional 400mg/Nm
3, developed regions 200mg/Nm
3; In plumbous Zn Cr coating, copper cobalt nickel emission of industrial pollutants standard GB25467-2010, sulfur dioxide (SO2) emissions limit value is 400mg/Nm
3; In steel sintering, pelletizing industrial air pollution thing discharge standard GB28662-2012, sulfur dioxide (SO2) emissions limit value is 200mg/Nm
3; Indivedual key area performs 100mg/Nm
3, even 50mg/Nm
3limit value, to the environmental protection of enterprise management strict demand is provided.
The ammonia process of desulfurization also has a defect to be to exist when low limit value desulfurization the problem of Ammonia valatilization, there is the effusion of a certain amount of ammonia in the tail gas of discharge, causes another and pollutes.To solve the problem of ammonia effusion, needing to increase other device, adding cost.Such as Chinese patent application 201110134692.5 proposes a kind of method reducing tail gas ammonia effusion, and newly-increased a set of venturi ammonia purifier between the demister and spraying layer at desulfurizing tower top, with cleaning of off-gas.But be limited to the defect of ammonia-process desulfurization technique itself, method used in the prior art can not reduce tail gas sulfur content further.
Hydrogen peroxide desulfurization is a kind of doctor treatment, and principle utilizes the strong oxidizing property of hydrogen peroxide to make sulfur dioxide be direct oxidation into sulfuric acid.This reaction is Strong oxdiative reaction, is swift in response and thoroughly, desulfuration efficiency is high, and operating cost is lower, therefore obtains the favor in industry gradually, has greatly the development trend replacing other traditional doctor treatment.But an important defect is, in large-scale production and application, the sulfur content containing the air inlet of sulfur dioxide is the distribution of air mass formula, and security causes anxiety, and such as blast in somewhere in 2013 in the commissioning process of hydrogen peroxide desulphurization plant.For overcoming the defect of existing traditional desulfur technology and being used alone the deficiency that peroxide passivation has, we have developed fuming furnace sulfur-containing tail gas desulfur technology of the present utility model, reduce discharging with the degree of depth realizing tail gas, and can when increasing cost not significantly, realize undergoing technological transformation upgrading to the old equipment of existing producer.
Utility model content
A kind of method that the purpose of this utility model is to provide fuming furnace sulfur-containing tail gas degree of depth to reduce discharging and device, the method adopts ammoniacal liquor-hydrogen peroxide combined desulfurization agent, that is first cooling dedusting pretreatment is carried out to sulfur-containing tail gas, then adopt ammonia desulfurizing process to carry out thick desulfurization, finally adopt peroxide passivation sulfur removal technology to carry out fine de-sulfur.After ammoniacal liquor-hydrogen peroxide combined depth desulfurization, in sulfur-containing tail gas, sulfur dioxide sulfur-bearing can be reduced to 20mg/Nm
3below, the requirement of existing every profession and trade discharging standards limit value is met.
Specifically, the technical solution adopted in the utility model is as follows:
The method that the fuming furnace sulfur-containing tail gas degree of depth reduces discharging, is characterized in that, said method comprising the steps of:
Thick desulfurized step: in alkaline desulfurizing tower, utilize ammoniacal liquor as desulfurizing agent, the absorbing liquid containing ammoniacal liquor is used fully to contact with sulfur-containing tail gas the sulfur dioxide absorbed in sulfur-containing tail gas, make the content of sulfur dioxide in tail gas reduce thus produce the tail gas of content of sulfur dioxide reduction, produce the absorption mother liquor absorbing sulfur dioxide simultaneously;
Fine de-sulfur step: the tail gas that this content of sulfur dioxide reduces is sent to acid desulfurizing tower, in acid desulfurizing tower, take hydrogen peroxide as desulfurizing agent, again carry out absorption process, sulfur dioxide and hydrogen peroxide react rapidly, generate the tail gas of dilution heat of sulfuric acid and deep desulfuration, and the tail gas of this deep desulfuration is delivered to exhaust system discharge
Wherein in thick desulfurized step, the mass fraction of ammoniacal liquor is 15-40%, preferred 25-30%, ammonium sulfite concentration in tower in absorption mother liquor is 20-180g/L, preferred 50-150g/L, more preferably 100-150g/L, bisulfite ammonium concentration are 150-400g/L, preferred 200-350g/L, temperature is 20-40 DEG C, and leacheate density is 15-20m
3/ (m
2h), in fine de-sulfur step, hydrogen peroxide mass fraction is 27%-70%, and in tower, in solution, hydrogen peroxide mass fraction is 0.1-8%, and sulfuric acid is 10-45%, and temperature is 25-40 DEG C, and leacheate density is 20-30m
3/ (m
2h), SO in emission
2concentration is less than 50mg/Nm
3, be more preferably reduced to 20mg/Nm
3below.
The absorption mother liquor discontinuity discharge absorbing sulfur dioxide produced in thick desulfurized step is for the production of ammonium sulfate, and the dilution heat of sulfuric acid produced in fine de-sulfur step is circulated to leading portion for neutralization.
Preferably, in thick desulfurized step, the content of sulfur dioxide in tail gas is made to be down to 1000mg/Nm
3below, more preferably 200 to 700mg/Nm is down to
3, most preferably 200mg/Nm
3below.
Preferably, before thick desulfurized step, also comprise pre-treatment step: take to fuming furnace sulfur-containing tail gas dust suppression of lowering the temperature, make temperature be brought down below 160 DEG C, dustiness is less than 50mg/Nm
3.
Preferably, described cooling measure comprises the combination of any one or more adopting surface-cooler, air cooling heat exchanger or directly spray water in hybrid cooling; Described dust suppression comprises the combination of any one or both adopted in sack cleaner or electric cleaner.
Preferably, described thick desulfurized step adopts one or more levels ammonia process washing absorption flow process.
Preferably, the ammonium sulfite generated in described thick desulfurized step is further processed into ammonium sulfate with ammonium bisulfite.In this case, the absorption mother liquor generated in described thick desulfurized step obtains solid ammonium sulfate after peroxidating, neutralization, decomposition, evaporation.
whereinthe neutralisation treatment of absorption mother liquor make use of the dilute sulfuric acid generated in fine de-sulfur step, that is the dilute sulfuric acid generated in fine de-sulfur step is back to the absorption mother liquor generation ammonium sulfate of leading portion for discharging in neutralized crude desulfurized step at least partly.More preferably, produce at mother liquid disposal the residual gas produced in the process of ammonium sulfate and be delivered to acid desulfurizing tower process further.
The invention also discloses a kind of device reduced discharging for the fuming furnace sulfur-containing tail gas degree of depth, described device comprises thick desulfurizer and fine de-sulfur device, it is characterized in that, thick desulfurizer is for adopting ammoniacal liquor to absorb the device of the sulfur dioxide in tail gas, and fine de-sulfur device is the device adopting hydrogen peroxide to absorb the sulfur dioxide in the tail gas of thick desulfurization further, thick desulfurizer comprises alkaline desulfurizing tower, ammoniacal liquor supply line, Recycling Mother Solution pipeline and mother liquid disposal device, fine de-sulfur device comprises acid desulfurizing tower, hydrogen peroxide supply line, hydrogen peroxide circulation line and sulfuric acid return pipeline, described sulfuric acid return pipeline UNICOM to the mother liquid disposal device of leading portion for carrying sulfuric acid neutralisation treatment absorption mother liquor.
In addition, described device can also comprise a return line, for being back to by the dilute sulfuric acid generated in fine de-sulfur device in thick desulfurizer to generate ammonium sulfate with the ammonia gas react in thick desulfurizer.
Further, at mother liquid disposal device, also pass-out pipeline UNICOM is to acid desulfurizing tower air inlet, and the residual gas for being produced by mother liquid disposal device is delivered in acid desulfurizing tower and processes.
Beneficial effect: the utility model adopts ammoniacal liquor-hydrogen peroxide combined desulfurization agent, compared with existing simple ammonia desulfurizing process, have desulfuration efficiency high, the degree of depth can be realized reduce discharging, prevent the safety issue, the integrated operation low cost and other advantages that cause the escaping of ammonia problem during the desulfurization of independent ammonia process low limit value, prevent independent hydrogen peroxide desulfurization.In the combined desulfurization adopting ammoniacal liquor-hydrogen peroxide combined desulfurization agent to carry out, the absorptive capacity of the leading portion ammonia process of desulfurization is large, and back segment hydrogen peroxide desulphurization reaction rapidly and thoroughly, tail gas residual sulfur dioxide content is extremely low, by-product sulfuric acid can supplement fresh water (FW), with leading portion absorption mother liquor during major part can be used for, produces valuable ammonium sulfate, the Sulphur ressource made full use of in tail gas generates value product, also fully produces economic benefit while not producing waste disposal burden.When adopting method and apparatus of the present utility model, can make full use of existing equipment, improvement cost is low, is a technology having prospect.
Detailed description of the invention
The utility model utilizes ammoniacal liquor-hydrogen peroxide combined desulfurization agent, to passing through or adopting the thick desulfurization of ammonia process and peroxide passivation fine de-sulfur process integration without pretreated tail gas, overcome desulfuration efficiency in existing ammonia desulfurizing process technology lower, for easily causing the problems such as the escaping of ammonia when realizing low-emission, the sulfur-containing tail gas through the thick desulfurization of ammonia process is adopted the further efficient removal of peroxide passivation sulfur removal technology again.
The method utilizing ammoniacal liquor-hydrogen peroxide combined desulfurization agent to carry out the reduction of discharging of the fuming furnace sulfur-containing tail gas degree of depth comprises the following steps:
First, first take cooling to sulfur-containing tail gas (as industries such as iron and steel, metallurgy, nonferrous smelting, chemical industry), dust suppression, makes its temperature be down to and is less than 160 DEG C, and dustiness is less than 50mg/Nm
3, meet ammonia desulfurizing process requirement.When sulfur-containing tail gas is not treated directly meet ammonia desulfurizing process requirement time, this step can be save.
Secondly, adopt ammoniacal liquor to be raw material to through pretreated sulfur-containing tail gas, carry out absorption process, generate ammonium sulfite after sulfur dioxide and ammonia react in gas, be further oxidized to into ammonium sulfate, after Separation of Solid and Liquid, obtain ammonium sulfite or ammonium sulfate byproduct.After the ammonia process of desulfurization, tail gas sulphur dioxide controls to be less than 1000mg/Nm
3, be more preferably down to 200 to 700mg/Nm
3, most preferably 200mg/Nm
3below.
Then, low containing SO 2 tail gas by after the ammonia process of desulfurization, then adopt hydrogen peroxide to absorb sulfur dioxide wherein, carry out desulfurization again, after desulfurization, tail gas sulphur dioxide is less than 20mg/Nm
3.
Pretreatment wherein containing SO 2 tail gas comprises the following steps:
Step I: cooling, containing SO 2 tail gas can adopt surface-cooler or air cooling heat exchanger or directly the measure such as water spray hybrid cooling realize gas temperature and be reduced to and be less than less than 160 DEG C.
Step II: dedusting, after step I, tail gas realizes the removal of dust-laden material in gas through the measure such as sack cleaner or electric cleaner.
Containing the ammonia desulfurizing process that the thick desulfurization of SO 2 tail gas adopts, one or more levels ammonia process washing absorption flow process can be chosen according to the sulfur-bearing of sulfur dioxide in tail gas, also according to market acceptance situation, absorption afterproduct can be accomplished ammonium sulfite or ammonium sulfate, for sale or personal.
Tail gas after the thick desulfurization of ammonia process adopts hydrogen peroxide to carry out fine desulfurizing technology desulfurization again, can choose tower and the absorption equipment of stuffing washing tower or the form such as void tower or hypergravity machine according to sulfur dioxide in tail gas content.
The device that the method that the utility model fuming furnace sulfur-containing tail gas degree of depth reduces discharging adopts comprises gas preprocessing part, ammonia process of desulfurization part, hydrogen peroxide disengagement section, three some processes methods and device organic assembling, realizes the fuming furnace sulfur-containing tail gas degree of depth and reduces discharging.
The a small amount of dilute sulfuric acid byproduct produced in peroxide passivation fine de-sulfur part, can be back to production system reuse, does technique supplementing water as gas washing in SA production can be back to dry absorption section; Also can be back in ammonia desulphurization absorption tower, after being combined with part ammonia, generate ammonium sulfate; Also directly as by-product sale, or can sell after being concentrated into finished acid.
The utility model adopts ammoniacal liquor-hydrogen peroxide combined desulfurization agent, and compared with existing simple ammonia desulfurizing process, desulfuration efficiency is high, and the content of sulfur dioxide in tail gas is less than 20mg/Nm
3, thus realize degree of depth reduction of discharging.Prevent the escaping of ammonia problem caused during the low limit value desulfurization of independent ammonia process, the ammonia of escape is also further oxided when fine de-sulfur, avoids further pollution.Improve security, the content through the sulfur dioxide in tail gas of thick desulfurization reduces, and owing to have passed through first processing procedure, the content distribution of sulfur dioxide obtains adjustment, and the reacting balance in hydrogen peroxide desulfurizing tower, makes security be improved.In addition compared to prior art, integrated operation cost is lower.
Below in conjunction with accompanying drawing and example, the utility model is further illustrated.
Below in conjunction with Fig. 1, detailed content of the present utility model is further described.
Fig. 1 is device flow chart of the present utility model, when carrying out flue gas desulfurization reduction of discharging in fuming furnace sulfur-containing tail gas depth minus arranging device of the present utility model, through following treatment step: 3 alkaline desulfurizing towers; 4 alkaline desulfur pumps; 5 ammonia vessels; 6 aqua ammonia pumps; 7 mother liquid disposal devices; 8 excavationg pumps; 9 sulfuric acid circulating pumps; 10 acid desulfurizing towers; 11 dioxygen water pumps; 12 dioxygen tanks; 13 sulfuric acid return pipelines; 14 residual gas pipelines; 15 Recycling Mother Solution pipelines.
First take by deduster 1, cooler 2 dust suppression of lowering the temperature to sulfur-containing tail gas, its temperature is down to and is less than 160 DEG C, dustiness is less than 50mg/Nm
3, meet ammonia desulfurizing process requirement.When sulfur-containing tail gas is not treated directly meet ammonia desulfurizing process requirement time, this step can be save.
Thick disengagement section and ammonia process of desulfurization part, to passing through or adopting ammoniacal liquor to be raw material without pretreated sulfur-containing tail gas, absorption process is carried out in alkaline desulfurizing tower 3, absorption mother liquor is circulated by Recycling Mother Solution pipeline 15, alkaline desulfur pump 4, discontinuity discharges mother liquor, and the mother liquor of cyclic part and the ammoniacal liquor blending transportation from ammonia vessel 5, aqua ammonia pump 6 are to tower top.Ammonium sulfite is generated and ammonium bisulfite enters mother liquor after sulfur dioxide in gas and ammonia react, absorption mother liquor discontinuity is discharged to mother liquid disposal device 7, be further oxidized to into ammonium sulfate, after Separation of Solid and Liquid, obtain ammonium sulfite or ammonium sulfate byproduct is discharged via excavationg pump 8.After the ammonia process of desulfurization, tail gas sulphur dioxide controls to be less than 1000mg/Nm
3, be more preferably down to 200 to 700mg/Nm
3, most preferably 200mg/Nm
3below.
Fine de-sulfur part and hydrogen peroxide disengagement section, low content of sulfur dioxide tail gas after thick for ammonia process desulfurization is delivered to acid desulfurizing tower 10, dioxygen water pump 11 draws hydrogen peroxide from dioxygen tank 12 and delivers to tower top, haptoreaction abundant with tail gas, the sulfuric acid discontinuity generated is discharged, at least part of sulfuric acid passes through sulfuric acid return pipeline 13 and is delivered to leading portion, a part returns sulfuric acid and delivers in mother liquid disposal device 7 and mother liquor, alkaline desulfur pump can also be delivered to, use alkaline desulfurizing tower and generate ammonium sulfate as reactor.The residual gas generated in mother liquid disposal device 7, by residual gas pipeline, merges with alkaline desulfurizing tower exhaust pipe road or is delivered to separately acid desulfurizing tower process.After acid desulfurizing tower desulfurization, tail gas sulphur dioxide is less than 20mg/Nm
3, can directly discharge.
Example 1
(1) thick desulfurization
Desulfurizing agent liquefied ammonia enters in alkaline desulfurizing tower with the dispersion of the form of ammoniacal liquor, after in tower, mother liquor mixes, through Recycling Mother Solution pump and Cemented filling to tower top, be evenly distributed on separatory sieve plate by knockout again, this process, the mass fraction controlling ammoniacal liquor is 25-30%, absorption mother liquor sulfite ammonium concentration 50-150g/L, bisulfite ammonium concentration 200-350g/L in tower, temperature 20-40 DEG C, leacheate density 15-20m
3/ (m
2h); Fuming furnace blowing flue gas enters in alkaline desulfurizing tower by flue through smoke air inlet, after fully reflecting, derives via flue gas gas outlet with the doctor solution be evenly distributed in tower.
(2) fine de-sulfur
Take hydrogen peroxide as desulfurizing agent, enter in tower through hydrogen peroxide inlet, then by the absorbing liquid circulating pump of external linkage and Cemented filling to tower top, in tower, upper strata is provided with spray thrower, controls water spray 450-500m
3/ h, the absorbing liquid under spray enters separatory filler, after the absorbing liquid in the flue gas now entered by smoke air inlet and separatory filler fully reacts, is discharged, enter high-altitude chimney emptying by flue gas gas outlet; This process control hydrogen peroxide solution mass fraction is 27%-70%, and in tower, in solution, hydrogen peroxide mass fraction is 0.1-8%, sulfuric acid is 10-45%, temperature 25-40 DEG C, leacheate density 20-30m
3/ (m
2h), SO in emission
2concentration is less than 20mg/Nm
3.
(3) accessory substance process
Control absorption mother liquor volume in alkaline absorbent tower and be no more than 85% of capacity, intermittent discharge mother liquor, the mother liquor of gained obtains solid ammonium sulfate after decomposition, neutralization, evaporation;
Control sulfuric acid concentration 10-45% in acid absorption tower, intermittent discharge sulfuric acid solution, the sulfuric acid solution of gained returns leading portion system, in and reuse.
Example 2
Use said method to carry out degree of depth reduction of discharging to fuming furnace sulfur-containing tail gas, exhaust flow is about 71000 m
3/ h, SO in flue gas
2concentration is 10000-15000 mg/Nm
3, alkaline desulfurizing tower ammonia inlet concentration 25.5%, mother liquor sulfite ammonium concentration is 130g/L, bisulfite ammonium concentration is 300g/L, controls reaction temperature 35 DEG C, leacheate density 18m
3/ (m
2h), flue gas enters acid absorption tower after the preliminary desulfurization of parlkaline desulfurizing tower; In acid desulfurizing tower, hydrogenperoxide steam generator inlet mass mark is 27.5%, and in tower, in solution, hydrogen peroxide mass fraction is 1.5%, and sulfuric acid is 30%, controls reaction temperature 35 DEG C, leacheate density 25m
3/ (m
2h), SO in emission
2concentration 50mg/Nm
3.Stable operation 24 hours, by-product solid ammonium sulfate 45 tons, reuse 30% sulfuric acid solution 5.5m
3.
Example 3
Certain non-ferrous smelt enterprise, the former flue gas of sulfur-bearing is plumbous smelting zinc oxide fuming furnace flue gas, gas flow 120000m
3/ h, flue-gas temperature 200 DEG C, SO 2 from fume 8000mg/Nm
3, dust-laden 200mg/Nm
3.Enter surface-cooler naturally to cool, flue-gas temperature is reduced to 150-160 DEG C, is then separated dust through sack cleaner, reduces dust to 50mg/Nm
3below; Then sulfur-containing smoke gas enters one-level, secondary, three grades of absorption towers successively, with ammonia spirit, cyclic absorption is carried out to sulfur dioxide in flue gas, the ammonium sulfite slurries that reaction generates, drain in oxidation furnaces and adopt drum air oxidation to be ammonium sulfate slurries, ammonium sulfate slurries, after concentrated, adopt centrifuge to be separated and obtain ammonium sulfate crystallization.
Tail gas 120000Nm after the ammonia process of desulfurization
3/ h(butt), containing sulfur dioxide 700mg/Nm
3, flue-gas temperature 38 DEG C, moisture content 5%; Flue gas enters in peroxide passivation absorption tower, with the sulfur dioxide absorbed containing hydrogen peroxide liquid-circulating in flue gas, reaction generation 12% dilute sulfuric acid, part is delivered to the dry absorption section in zinc abstraction Sulphuric acid workshop, part is transported in the absorption tower of the ammonia process of desulfurization, reacts generate ammonium sulfate crystallization with ammoniacal liquor wherein.
After peroxide passivation desulfurization, tail gas sulphur dioxide is less than 20mg/Nm
3, emptying through emptying chimney.
With specific embodiment, embodiment of the present utility model is described in detail by reference to the accompanying drawings above, but the utility model is not limited to above-mentioned embodiment, in the ken that art those of ordinary skill possesses, can also make a variety of changes under the prerequisite not departing from the utility model aim.