CN202942800U

CN202942800U - Desulfurization and denitrification combined system for sintering flue gas

Info

Publication number: CN202942800U
Application number: CN 201220668482
Authority: CN
Inventors: 冷廷双; 宋存义; 余广炜; 赵荣志; 商春礼
Original assignee: 首钢总公司
Priority date: 2012-12-06
Filing date: 2012-12-06
Publication date: 2013-05-22

Abstract

The utility model provides a desulfurization and denitrification combined system for sintering flue gas. The system comprises a flue gas desulfurization device, a bag type dust collector connected with the flue gas desulfurization device, a pressurizing fan connected with the bag type dust collector, a flue reheating device connected with the pressurizing fan and a flue gas denitrification device connected with the flue reheating device. The flue gas desulfurization device comprises a desulfurization absorption tower and a digesting and mixing device for an absorbent arranged on the upper part of the desulfurization absorption tower. An absorbent circulating device is arranged between the desulfurization absorption tower and the bag type dust collector. The flue gas denitrification device comprises an SCR (Selective Catalytic Reduction) reactor as well as a reducing agent preparation device and a catalyst regenerating device arranged on the SCR reactor. The utility model provides the desulfurization and denitrification combined system for sintering flue gas, so that not only are desulfurization and denitrification of sintering flue gas effectively realized, but also original production media are effectively utilized to save energy.

Description

A kind of sintering flue gas desulfurization denitration combined system

Technical field

The utility model relates to prevention and control of air pollution field, particularly a kind of sintering flue gas desulfurization denitration combined system that is applicable under low consistency conditions.

Background technology

Sintering circuit is important step in technique before iron in the long flow process of Ferrous Metallurgy.Produce the proportion maximum that various air pollutants accounts for total emission volumn in whole metallurgical production process in sintering production process.At interior gas chromatography, also comprise particulate species pollutant such as dust-like, alkali metal, various heavy etc. comprising gaseous contaminant such as sulfur dioxide, nitrogen oxide, PCDD/F.Each area uses raw materials for sintering very large from the different sinter fume concentration of emission differences that cause of fuel.Sulfur dioxide concentration is from 500-5000mg/Nm ³In scope, nitrogen oxide is at 250-500mg/Nm ³Scope in.

Along with the development of national economy and the people raising day by day to environmental protection requirement, the Eleventh Five-Year Plan period in, flue gas of sintering machine is carried out on a large scale, that puts into commercial operation has wet method and two kinds of main stream approach of semidry method.The sintering device flue gas denitration is not carried out.National environmental protection section has listed nitrogen oxide in " 12 " overall control index, must be able to carry out the emission reduction work of nitrogen oxide when need to carry out flue gas desulfurization work at present.

At present the steel industry sintering flue gas desulfurization has been carried out nearly 10 years, and the whole bag of tricks has obtained application, various technology constantly grope with practice process in level off to maturation.But also be in space state in sinter fume denitration field, denitrating flue gas has obtained using very widely at thermal power industry, and the SCR catalytic reduction emission-reducing technology of making reducing agent with ammonia is most widely used.But sintering is different from power plant, and sintering device flue gas and coal-fired boiler in power plant flue gas are very different, and it is impracticable the SCR of power plant denitrating technique directly being moved on the sintering machine of steel industry.

Sintering device flue gas complicated, fluctuation are large, have following features: the one, and exhaust gas volumn is large, and the exhaust gas volumn that sintering deposit per ton produces is at 3500-5000m ³/ h (operating mode); The 2nd, NOx fluctuation of concentration is large, and concentration range is generally at 15-700mg/Nm ³The 3rd, each bellows smoke temperature change is large, is generally 50 ℃-400 ℃; The 4th, flue gas flow changes greatly, and amplitude of variation can reach 40% left and right; The 5th, flue gas moisture content is large and unstable, is generally 10%-13%; The 6th, oxygen content is high, is generally 13%-19%; The 7th, contain multiple pollutant in flue gas, particle-removing thing, SO ₂, outside NOx, also contain alkali metal, heavy metal, PCDD/F and other gas chromatography; The 8th, the NOx mean concentration in total flue gas is on the low side, is generally 250-400mg/Nm ³, far below power plant's alkene coal burning boiler flue gas, be unfavorable for improving removal efficiency; The 9th, power plant's SCR art is copied mechanically on sintering machine, due to the consumption of catalyst and ammonia reducing agent will the NOx of the unit of making to remove cost surprisingly high.

The flue gas desulfurization and dedusting technology can be summed up as semidry method and two kinds of forms of wet method at the example that sintering art is used at present, type difference according to the reactive absorption tower in every kind of form forms again different process routes, but can be summed up as two kinds of forms from reaction mechanism aspect discussion flue gas desulfurization technique: first, alkaline absorbent also liquid form participates in reaction, after reaction, absorbent still exists with liquid form, is wet method comprising lime stone (lime)-gypsum, ammonia process, ionic liquid method; The second, alkaline absorbent also dry state form or hygrometric state form participates in reaction but reacted absorbent is dry state does not have waste water and produce, this reaction principle can be summed up as the semi-dry desulphurization technology.These two kinds of sulfur removal technology routes all have the example of application at home.

Gas denitrifying technology mainly contains three kinds: (SeleCtiveCatalytiCReduction is called for short SCR to SCR, selective catalytic reduction), SNCR (SeleCtiveNon one CatalytiCReduction, be called for short SNCR, the SNCR method) and catalytic oxidation/reducing process.

Carry out denitrating flue gas in sinter fume improvement field and do not give enforcement owing to being subject to flue-gas temperature always, for the SCR technique that is similar to chemical method, flue-gas temperature is difficult to realize that lower than the environment of 300 ℃ the reaction of denitration occurs, not carrying out also that in CONTINENTAL AREA OF CHINA sintering device flue gas is carried out the SCR denitration at present processes, the nitrogen oxide of the sintering circuit of steel company is removed the flue gas reheat mode that adopts with more than pretreated fumes temperature increase to 280 ℃ in Taiwan, then carries out denitration reaction.

In order to realize the enforcement of denitrating flue gas, guarantee to enter into temperature and the cleanliness factor of the front flue gas of SCR system, in order to reach the restriction of two kinds of restrictive conditions, install burner additional and the heating of lighting a fire at flue, concrete realization effectively utilizes to adapt to the sintering circuit energy with reference to the thermal source of sintering pallet ignition system.

The utility model content

Technical problem to be solved in the utility model is to provide a kind of sintering flue gas desulfurization denitration combined system that is applicable under low consistency conditions.

For solving the problems of the technologies described above, the utility model provides a kind of sintering flue gas desulfurization denitration combined system, comprises flue gas desulfur device, the bagroom that is connected with flue gas desulfur device, the booster fan that is connected with bagroom, the flue reheater that is connected with booster fan, reaches the equipment for denitrifying flue gas that is connected with the flue reheater.

Further, described flue gas desulfur device comprises desulfuration absorbing tower and is arranged on digestion and the mixing arrangement of the absorbent on desulfuration absorbing tower top.

Further, be provided with the absorbent EGR between described desulfuration absorbing tower and bagroom.

Further, described equipment for denitrifying flue gas comprises the SCR reactor and is arranged on reducing agent preparation facilities and catalyst regeneration device on the SCR reactor.

What further, described SCR reactor adopted is fixed bed haptoreaction formula SCR reactor.

Further, described booster fan adopts axial fan or centrifugal fan.

Further, be provided with the coal gas ignition nozzle in described flue reheater.

A kind of sintering flue gas desulfurization denitration combined system that the utility model provides has the following advantages:

1, adopted flue gas desulfurization and denitrification to share the arranged in form of a Fans, and this blower fan is arranged in the middle of desulfurizer and denitrification apparatus, can satisfies the pressure loss that desulfurization overcomes, avoided simultaneously the impact of smoke moisture increasing on subsequent handling after denitration.

2, adopted novel flue gas desulfur device, adopt special digestion and mixing arrangement, and utilize the free wind speed of flue gas absorbent to be carried out the different separation of granularity in the absorption tower, the energy waste that minimizing all circulates and causes due to absorbent, this layout can reduce the internal circulating load of desulfurization absorbent, reduce the use amount of desulfurizing agent, reduce effluxing of accessory substance, coordinate the absorbent of collecting with bagroom to form circulation.

3, adopt the coal gas ignition arrangement of nozzles to be used for flue gas is heated in the flue reheater.Use the existing fuel of sintering plant, and utilize the existing used heat of sintering plant, maximally utilise the existing every energy medium condition of sintering plant.

4, this system can not arrange bypass, if accident condition is arranged in commercial Application, system for desulfuration and denitration can carry out the medium isolated operation, and making desulfuring and denitrifying apparatus become can by the passage of flue gas, guarantee system not to be exerted an influence.

5, native system is specially adapted to the transformation of existing sintering system, the front sintering system is not impacted.

Description of drawings

The system construction drawing of a kind of sintering flue gas desulfurization denitration combined system that Fig. 1 provides for the utility model embodiment.

The specific embodiment

Referring to Fig. 1, a kind of sintering flue gas desulfurization denitration combined system that the utility model embodiment provides, the bagroom 3 that comprise flue gas desulfur device, is connected with flue gas desulfur device, the booster fan 6 that is connected with bagroom 3, the flue reheater 7 that is connected with booster fan 6, and the equipment for denitrifying flue gas that is connected with flue reheater 7.Wherein, flue gas desulfur device comprises desulfuration absorbing tower 2 and is arranged on the absorbent digestion and mixing arrangement 5 on desulfuration absorbing tower 2 tops, is provided with absorbent EGR 4 between desulfuration absorbing tower 2 and bagroom 3.Equipment for denitrifying flue gas comprises SCR reactor 8 and is arranged on reducing agent preparation facilities 9 and catalyst regeneration device 10 on SCR reactor 8, is provided with the coal gas ignition nozzle in flue reheater 7.

The operation principle of a kind of sintering flue gas desulfurization denitration combined system that the utility model embodiment provides:

The flue gas that pallet 1 is collected is through entering into desulfurization reaction tower 2 after electric cleaner, enter into absorption tower 2 through the fresh absorbent after absorbent digestion and mixing arrangement 5, mix with the flue gas through desulfuration absorbing tower 2 reaction of completing desulfurization, enter into bagroom 3 through the reacted flue gas of desulfuration absorbing tower 2,, be back to and completed the recycling of desulfurization absorbent in desulfuration absorbing tower 2 through absorbent EGR 4 through the collected absorbent of bagroom 3.

Enter into booster fan 6 through the flue gas after bagroom 3 purifying and dedustings flue gas is carried out supercharging.At first to consider for the selection of booster fan 6 and overcome the gather dust pressure loss in process of desulfurization, to leave for follow-up denitrating flue gas process enough affluence amounts simultaneously, to ensure the pressure reduction of 1000Pa left and right for follow-up denitrating flue gas process, the selection of booster fan 6 can be carried out flexible arrangement according to the variation of field conduct condition and the requirement of actual production, can adopt axial fan or centrifugal fan.

Entering flue gas reheater 7 through the flue gas after booster fan 6 superchargings heats, be provided with the coal gas ignition nozzle in flue gas reheater 7, utilize existing fuel system to light heating, and utilize the hot blast auxiliary combustion of sintering, make flue-gas temperature reach flue gas and carry out 280 ℃ 300 ℃ of the desired temperature of denitration reaction.

Be heated to through flue gas reheater 7 and enter SCR reactor 8 after required temperature and carry out denitration reaction with absorbent, the absorbent that SCR reactor 8 uses comes from the reducing agent preparation facilities 9 that is arranged on SCR reactor 8, also be provided with catalyst regeneration device 10 on SCR reactor 8, the regeneration that is used for SCR reactor 8 absorbents is used.SCR reactor 8 adopts fixed-bed type haptoreaction form, catalyst arrangement is in fixed bed, absorbent sprays from the flue of 8 of flue gas reheater 7 and SCR reactors and injects, the formation absorbent fully mixes with flue gas, and react in SCR reactor 8, the efficient of denitration can reach 60%-70%.

At last, the temperature of the flue gas after the process denitration remains on 120 ℃ of left and right, discharges from chimney 10, meets the safe temperature that chimney effluxes.

A kind of sintering flue gas desulfurization denitration combined system that the utility model embodiment provides, integrated flue gas desulfurization and the gas denitrifying technology of having succeeded at present and having used, with two kinds ripe process route connect, wherein blower fan is arranged in the middle of two kinds of techniques, can make security of system stable operation, the reaction condition of two kinds of technique needs has difference, reach the reaction temperature requirement of two kinds of techniques by the control of flue-gas temperature, reach energy-conservation effect by controlling to greatest extent reaction temperature.

A kind of sintering flue gas desulfurization denitration combined system that the utility model embodiment provides is utilized existing ripe smoke gas treatment technology, in conjunction with existing fuel system, realizes the reaction condition of flue gas desulfurization and denitration.For the Dry FGD device, the step absorbent use device that adopts absorbent can efficient circulation to utilize, adopt low-temperature catalyzed reduction reaction principle for the denitration reaction device, utilized original production medium when completing desulfurization and denitrification reaction, gather materials on the spot can efficient, flexible arrangement technology, be particularly suitable for the transformation of old plant area.

It should be noted last that, the above specific embodiment is only unrestricted in order to the technical solution of the utility model to be described, although with reference to example, the utility model is had been described in detail, those of ordinary skill in the art is to be understood that, can modify or be equal to replacement the technical solution of the utility model, and not breaking away from the spirit and scope of technical solutions of the utility model, it all should be encompassed in the middle of claim scope of the present utility model.

Claims

1. a sintering flue gas desulfurization denitration combined system, is characterized in that: comprise flue gas desulfur device, the bagroom that is connected with flue gas desulfur device, the booster fan that is connected with bagroom, the flue reheater that is connected with booster fan, reach the equipment for denitrifying flue gas that is connected with the flue reheater.

2. sintering flue gas desulfurization denitration combined system according to claim 1 is characterized in that: described flue gas desulfur device comprises desulfuration absorbing tower and is arranged on digestion and the mixing arrangement of the absorbent on desulfuration absorbing tower top.

3. sintering flue gas desulfurization denitration combined system according to claim 2, is characterized in that: be provided with the absorbent EGR between described desulfuration absorbing tower and bagroom.

4. sintering flue gas desulfurization denitration combined system according to claim 1 is characterized in that: described equipment for denitrifying flue gas comprises the SCR reactor and is arranged on reducing agent preparation facilities and catalyst regeneration device on the SCR reactor.

5. sintering flue gas desulfurization denitration combined system according to claim 4 is characterized in that: what described SCR reactor adopted is fixed bed haptoreaction formula SCR reactor.

6. sintering flue gas desulfurization denitration combined system according to claim 1, is characterized in that: described booster fan employing axial fan or centrifugal fan.

7. sintering flue gas desulfurization denitration combined system according to claim 1 is characterized in that: described flue reheater is for being provided with the coal gas ignition nozzle in flue.