CN106064019A

CN106064019A - Circulating flue gas desulfurization technology in nsp kiln

Info

Publication number: CN106064019A
Application number: CN201510192789.XA
Authority: CN
Inventors: 齐砚勇; 刘端
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-04-22
Filing date: 2015-04-22
Publication date: 2016-11-02

Abstract

Circulating flue gas desulfurization technology in nsp kiln, it relates to the SO that a kind of manufacture of cement fuel produces₂Removing sulfuldioxide.Utilize 5 grades of cyclone cylinder high-temperature materials of part, cool down through 3 grades of suspension cooling systems, have raw material to enter kiln slide fastener elevator feeding C1 cyclone cylinder, with SO in flue gas₂Reaction, forms CaSO3, it is achieved flue gas desulfurization.The high temperature air of CL1 outlet converges with C5, enters kiln raw material about 3%, it is not necessary to additionally add desulfurizing agent.The present invention is used for cement plant flue gas desulfurization.

Description

Circulating flue gas desulfurization technology in nsp kiln

Technical field

The invention belongs to field of cement production, utilize circulation in nsp kiln, with a new technique of hot raw material desulfurization, solve the problem high with desulfurizing agent desulphurization cost.

Background technology

Since the later stage sixties 20th century, flue gas desulfurization technique quickly grows, from the Document system delivered, its technique has kind more than 200, but these methods are in laboratory stage or bench-scale testing stage mostly, only more than the 10 kind of flue gas desulfurization technique put into practice at present can be divided into wet method, dry method and semidry method three major types by the form of its desulfurization method and desulfurization reaction product.Typically the sulfur removal technology being present in aqueous solution or dress liquid as the desulfurization product that desulfurizing agent generates using aqueous solution or dress liquid is called wet processing, the desulfurization product generated for desulfurizing agent with aqueous solution or the dress liquid sulfur removal technology as dry state is called semidry process, the desulfurizing agent added be dry state desulfurization product be still that the sulfur removal technology of dry state is referred to as dry process.

Wet Flue Gas Desulfurization Technology, such as limestone/lime wet method, desulphurization reaction speed is fast;Desulfurization absorption generates with product and carries out under middle low temperature state;Desulfuration efficiency is high.But equipment is complex, and generally there is rotten candle problem, operation and maintenance cost is high and causes secondary pollution etc..Dry flue gas desulphurization technology, as sprayed desulfurization technology in stove, solid sorbent adsorbent reacts with S02 under dry state, and processes or recycling desulfurizer under dry state;Flue gas without significant hypothermal, spreads after being beneficial to discharge in sweetening process;Secondary pollution without waste liquid.But response speed is slow, and desulfuration efficiency and sorbent utilization are low.

Sulfur in quality coal in cement kiln systems is brought into by raw material and fuel.Sulfur in raw material is presented in organic sulfur compound, sulfide (simple sulfide or multiple sulfide such as troilite) or sulfate, and elemental sulfur is negligible.Present in raw material, sulfate is generally do not form SO at pre-heating system₂Gas, the most all can enter kiln system.A portion sulfate can thermal zone in kiln be decomposed, the SO of generation₂Gas moves to kiln tail with kiln gas, when arriving minimum two-stage preheater equitemperature lower region, it is condensate on the raw material that temperature is relatively low, and enters in kiln with the heavy collection of raw material, forming a circulation between preheater and kiln, undecomposed sulfate then can leave kiln system along with grog.The sulfur existed otherwise in raw material, then can be at 300 ~ 600 DEG C of oxidized generation SO₂Gas, occurs mainly in the second level cyclone cylinder of five (four) level preheaters or the third level cyclone cylinder of six grades of preheaters.In precalciner system, fuel is fed by kiln hood and dore furnace.The SO that dore furnace fuel combustion generates₂A large amount of activity CaO that the stove that can be decomposed exists absorb, the CaSO of generation₄Entered in kiln by kiln tail smoke-box through lowermost level cyclone cylinder with material.The SO that the fuel of kiln hood feeding produces₂Gas thermal zone in kiln with sulfate can decompose the SO produced₂The course that gas experience is similar.It can be considered that: the sulfur contained by fuel is all absorbed by CaO and basic anhydride, generates sulfate.

Sulfur in raw material, in addition to sulfate, mainly exists with sulphided form.The SO that sulfide-oxidation produces₂Can be partially absorbed when by higher level's cyclone cylinder, remaining is then discharged from preheater together with waste gas.If waste gas is used for drying material, then SO₂Raw material grinding mill is absorbed further.However it is necessary that and be pointed out that: in the case of temperature is less than 600 DEG C, CaCO₃To SO₂Absorption efficiency CaO to be far below.CaCO in two-stage preheater above₃Resolution ratio is relatively low, and the most a small amount of CaO is by flue gas from high-temperature part band up, and therefore absorption efficiency is the lowest.Add now humidity relatively low and discharge before the time of staying shorter, SO₂Concentration of emission may be the highest.If there is organic sulfur compound, its oxidation behavior is close with troilite.

Guizhou Wengfu phosphate fertilizer plant built up the ardealite preparing granular ammonium sulfate device that production capacity is 250,000 t/a in 2011, and this device can consume ardealite solid-state waste residue every year more than 600,000 t, simultaneously discharge 300,000 t waste calcium carbonate.This factory uses suspended state calcining-fast cooling technology, builds up a 100000 t/a calcium carbonate slag suspended state calcinings-quick cooling and prepares the production line of active lime, and lime product is for flue gas desulphurization, chemical plant sewage disposal or is used as construction material etc..

SO in nsp kiln flue gas₂Flue gas is entered from the sulphur content solution in fuel combustion and raw material.Theoretical research and tens line measured results show, in most cases, and the SO that fuel combustion produces₂, substantially absorbed by carbonate decomposition CaO out in 5 grades of cylinders.And the sulfur in raw material, under the condition of high temperature, (C4 level) decomposes, low in moisture, under CaO content low environment, not with the carbonate reaction in raw material, causes sulfur content in C1 exiting flue gas to exceedCountryStandard.Use conventional wet desulfurization method, desulfurizing agent, or newly added equipment need to be bought.Not only investment is big, complex management, and desulfurizing agent cost is high, wet desulfurization gypsum difficult treatment.Compared with traditional method, this method directly uses 5 grades of cyclone cylinder materials, cools down through 3 grades of cyclone cylinders, very little on kiln system impact.It is fed directly into C1 cyclone cylinder desulfurization.It is not required to buy desulfurizing agent, closed operation, non-exhaust emission, does not increase kiln system energy consumption.

Summary of the invention

The present invention proposes a kind of method of high-temperature material desulfurization utilizing part C5 to export, and reduces C1 exiting flue gas content.Its process engineeringSuch as figure 1

Process description

From nsp kiln C5 cyclone cylinder high-temperature material, mix with CL2 cooling cyclone cylinder low exit temperature air, lower the temperature, enter CL1 and cool down cyclone cylinder, complete gas solid separation.High temperature raw material order enters CL2, CL3 and cold air heat exchange, reduces the temperature to 150 DEG C, enters raw material through machine for zipper and enter kiln elevator, enter C1 cyclone cylinder, with SO in flue gas₂Reaction, forms CaSO₃, it is achieved flue gas desulfurization.The high temperature air of CL1 outlet converges with C5 outlet.Three grades of cooling cooling systems that suspend are entered from the Calx of the 900 of decomposition furnace outlet DEG C.Material is quickly cooled down by the mode using suspended state air-cooled, and cooling effectiveness is high, and the temperature between cyclone cylinders at different levels drops all more than 110 DEG C.After three grades of whirlwind coolings, outlet mass temperatures is below 60 DEG C.Such as figure 2Shown in, thermal current all reenters dore furnace and recycles, and heat recovery efficiency is high, reduces energy consumption;Add the oxygen-supplying amount of dore furnace simultaneously, make coal dust fully burn.It addition, the most air-cooled porosity that can improve CaO of the suspended state of Calx, refine CaO crystallizable mineral, be effectively improved the quality of Calx finished product.

Desulfurizing agent (calcination raw material) consumption

Enter kiln raw material about 3%, export SO depending on C1₂Content, is slightly changed.

Specification of equipment

Example

Wanzhou prefecture of Chongqing 5000t/d cement plant uses quick lime desulfurization, and its Clinker Composition is:

Tail smoke evacuation chimney on-line checking shows, average smoke discharge amount 900,000 m³/ h(temperature about 100 DEG C), quick lime per ton, it is possible to decrease SO₂Amount is 70 ~ 80mg/m³.The flue gas of kiln tail discharge is discharged after Vertical Mill by C1 outlet exhaust, and owing to leaking out, in flue gas, oxygen content can rise to 10% from about 2%, the highest.Equivalent C1 exports desulfurization, often gives birth suddenly Calx, it is possible to decrease SO₂Amount is 120 ~ 140mg/m³。

Accompanying drawing explanation

Figure 1It it is the engineering process of the present inventionFigure；

Figure 2It it is technological processFigure。

Claims

1. circulating flue gas desulfurization technology in nsp kiln, will mix with CL2 cooling cyclone cylinder low exit temperature air, lower the temperature from nsp kiln C5 cyclone cylinder high-temperature material, enter CL1 and cool down cyclone cylinder, complete gas solid separation；High temperature raw material order enters CL2, CL3 and cold air heat exchange, reduces the temperature to 150 DEG C, enters raw material through machine for zipper and enter kiln elevator, enter C1 cyclone cylinder, with SO in flue gas₂Reaction, forms CaSO₃, it is achieved flue gas desulfurization；The high temperature air of CL1 outlet converges with C5 outlet.

Circulating flue gas desulfurization technology in nsp kiln the most according to claim 1, is characterized in that: the hot raw material carbonate decomposition of C5 outlet is complete, and CaO content is high, beneficially SO₂Absorb.

Circulating flue gas desulfurization technology in nsp kiln the most according to claim 1, is characterized in that: the consumption of desulfurizing agent (calcination raw material) is low, about enters kiln raw material 3%, little impact on production.

Circulating flue gas desulfurization technology in nsp kiln the most according to claim 1, is characterized in that: 5 grades of cyclone cylinder materials, is fed directly into C1 cyclone cylinder desulfurization, cools down through 3 grades of cyclone cylinders, very little on kiln system impact.

Circulating flue gas desulfurization technology in nsp kiln the most according to claim 1, is characterized in that: is not required to buy desulfurizing agent, closed operation, non-exhaust emission, does not increase kiln system energy consumption.