CN1247841A

CN1247841A - Cement baking process in kiln with dry preheater by using city garbage as material

Info

Publication number: CN1247841A
Application number: CN99119739A
Authority: CN
Inventors: 陈华魁; 江瑞莲; 朱克文; 朱文捷; 朱剑峰; 陈志�; 陈燕; 陈青
Original assignee: 陈华魁
Priority date: 1999-09-29
Filing date: 1999-09-29
Publication date: 2000-03-22

Abstract

The cement baking process includes four steps. Selected inorganic components, after metal is eliminated, as cement raw material are incinerated in incinerator into garbage ash and the produced waste gas is absorbed by high-temperature CaO in vertical pre-heater system to obtain innocuous matter. Part of the garbage ash is compounded in dry mill into raw meal together with other ingredients and the other part together with cement is pulverized in cement mill to obtain mixed cement material. Duff as fuel is provided to incinerator and rotary kiln. The present invention provides one effective way of changing waste into useful resource.

Description

With city garbage as material, with the method for dry method preheater kiln cement baking

The present invention relates to a kind ofly, be used for the method for method preheater kiln cement baking, belong to domestic rubbish disposal and technology of producing cement field with city garbage as material.

Existing treating method for urban garbage has method, air storage and landfills such as air storage, landfill, burning, and floor space is big, and causes ground and groundwater pollution, is just phasing out and limiting this kind method; Adopt burning method more at present, but contain Cl in the flue gas that burns ₂, F ₂, SO ₂Etc. objectionable constituent, atmosphere pollution also has harmful substances in the rubbish ash after the burning, and rubbish ash amount is also very big, can not find suitable purposes and takies the farmland in a large number.

The purpose of this invention is to provide a kind of with city garbage as material, method with dry method preheater kiln cement baking, because temperature can reach about 1500 ℃ in the cement rotary kiln, in this hot environment, objectionable impurities in the rubbish, metropolitan decomposes, and has a large amount of CaO in cement raw material and the rubbish ash, at high temperature CaO is good absorption agent, can be with obnoxious flavour Cl ₂, F ₂, SO ₂Aspiration is received, and generates CaCl ₂, CaF ₂, and CaSO ₄, making like this and only contain conventional dust and waste gas in the waste gas, obnoxious flavour is few, and the rubbish ash composition, the composition calculating according to contained material is equivalent to natural mineral feldspar composition, can adjust batching fully, is made into conventional silicate cement raw material composition; And if there is an objectionable constituent its centre, also can in hydrated cementitious and solidification process, be solidificated in the concrete, can not work the mischief.So municipal wastes is made raw material,, can thoroughly dispose municipal wastes with dry method preheater kiln cement baking.

For achieving the above object embodiment of the present invention such as following:

At first municipal wastes is selected through artificial, selection by winnowing, magnetic separation, metal species is sent the smeltery, and remaining essential substance has: sand, pottery, glass, ashes, concrete, loess, brick, materials such as refractory materials, except that combustiblematerials, its composition is roughly as calculated:

??SiO ₂	??Al ₂O ₃	??Fe ₂O ₂	??CaO	??MgO	??SO ₃	Cl ^-(muriate)
??SiO ₂	??Al ₂O ₃	??Fe ₂O ₂	??CaO	??MgO	??SO ₃	Cl ^-(muriate)	40～60％	?10～20％	??5-10％	?20～60％	??1～5％	??2-8％	????2-10％

Roughly be the equal of the feldspar composition below, be well suited for as cement raw material.Below referring to accompanying drawing 1, with city garbage as material, with the process flow sheet of dry method preheater kiln cement baking, step is as follows:

1. the inorganics after the sorting is removed metal, remainder is made cement raw material entirely, at first send into incinerator (1), burn through working as fuel with coal dust, the waste gas of generation enters shaft preheater (3) through air draft flue (2), passes through II level whirlwind tube (4) successively, I level whirlwind tube (5), conditioning tower (6), exhaust blower (7), dust precipitator (8) enter chimney (9), drain into atmosphere.In armamentarium and pipeline that gas passes through, because a large amount of CaO particles and temperature height are arranged, active big, route is long, and toxic gas sulphur, chlorine, fluorine effect with waste incineration produces become nontoxic CaCl ₂, CaF ₂, and CaSO ₄

2. rubbish burns the rubbish ash that generates in incinerator, delivers to raw material bistrique storehouse (10) and cement bistrique storehouse (11) respectively; Deliver to the rubbish ash in raw material bistrique storehouse (10), with Wingdale; Clay, iron powder cooperate, through metering, send into dry method raw material mill (12), the additional proportion of rubbish ash is 20～60% by weight, according to the raw ingredients requirement, change the aforementioned proportion scope, deliver to air lift mud pump (13), enter I level whirlwind tube (5) then in order through the raw material powder of grinding, II level whirlwind tube (4) and shaft preheater (3) are sent rotary kiln (14) at last to; In kiln, burn till grog through 1400 ℃～1600 ℃, flow into cooler (15), deliver to cement bistrique storehouse (16) at last.

3. the cement clinker that burns till is through being metered into proper amount of gypsum and from 5～15% the rubbish ash that incinerator (1) is sent here, being mixed into cement grinding mill (22) and wearing into cement.

4. fuel system: raw coal is delivered to coal mill bistrique storehouse (17), feeding coal mill (18), the coal-grinding powder that produces coal is delivered to Pulverized Coal Bin (19), and wherein a part is calcined rubbish in feeding machine (20) feeding incinerator (1), and another part is calcine cement in feeding machine (21) feeding rotary kiln.

A complete set of system is the cement old process in the schema, conventional equipment, only the treatment system of rubbish is introduced the cement manufacturing process, as the crude fuel utilization, not only handled rubbish but also increased production cement, reduce cement cost, in this process, absorbed toxic gas through high temperature CaO again, become harmless cement composition.

The cement composition scope of making is as follows:

????SiO ₂	???Al ₂O ₃	????Fe ₂O ₃	????CaO	????MgO	????SO ₃
????SiO ₂	???Al ₂O ₃	????Fe ₂O ₃	????CaO	????MgO	????SO ₃	??12～20％	??8～15％	????2-7％	??50～65％	??0.5～1％	????3-8％

The cement of making meets cement mark Chinese Industrial Standards (CIS) 425 ^#, 525 ^#With 625 ^#Three kinds, be ordinary Portland cement, short-term strength cement and hydraulic engineering cement can be used for the urban sewage engineering, rural area drainage system, underground infrastructure, highway, railway engineering etc.

Advantage of the present invention is:

1. be a kind of effective way that becomes waste into renewable resource with municipal wastes as the raw material mud of heating up water, and the cement of producing can reach the level of normal silicate and short-term strength cement, can make south 425 ^#, 525 ^#, 625 ^#Three kinds of cement that meet the cement mark Chinese Industrial Standards (CIS).

2. in the cement rotary kiln calcination system, temperature can reach 1400 ℃～1600 ℃, and under this hot environment, and the CaO in the raw material is active high, as chemical absorber can with burn the obnoxious flavour Cl that rubbish produces ₂, F ₂, SO ₂Produce chemical reaction and generate CaCl ₂, CaF ₂And CaSO ₄Etc. harmless composition; The rubbish ash component is as shown in table 1, and heavy metal and harmful element content all do not surpass the cement raw material allowed band.And if any a small amount of nuisance such as chromium, also curablely in the use in concrete, can not work the mischief.

3. make crude fuel with rubbish, with dry method preheater kiln cement baking total system all with the cement old process, conventional equipment does not increase any new installation, new technology can reduce the crude fuel cost greatly.

4. with Beijing example, producing the domestic refuse amount every day is 13000 tons, as with 3.5 * 60 meters rotary kiln production lines of 6 φ, every production line treating refuse (not Shai Xuan original state rubbish) is 2200 ton per days, article six, line is 13200 ton per days, the domestic refuse of Beijing can be disposed fully, and 6000 tons of cement can be produced every day.

Description of drawings: Fig. 1 is a city garbage as material, with the process flow sheet of dry method preheater kiln cement baking.

After domestic waste is removed the material of other industry energy usefulness through screening, can all supply with the cement mill, broken during because of screening, can carry out sealed reactor earlier puts, deliver in the incinerator by rotary conveyor through automatic gauge then, the fine coal heating that is blown into, furnace temperature can reach 1200 ℃, nuisance in the rubbish is oxidized, the nuisance that some decomposition temperature is higher is still stayed in the rubbish ash, goes out about about 1000 ℃ of furnace exhaust this moment, enter kiln tail system and handle, successively pass through shaft preheater with the waste gas of rotary kiln; II level whirlwind tube; I level whirlwind tube, with the high-temperature high concentration absorption agent CaO effect in the system, make chlorine, fluorine gas and sulfur dioxide gas in the rubbish waste gas generate harmless calcium chloride, Calcium Fluoride (Fluorspan) and calcium sulfate, these materials are accepted by the conditioning tower of back and dust precipitator, get rid of nontoxic waste gas.The rubbish ash that burnt at incinerator (1), behind the batching grinding, the dust of accepting with dust precipitator, after metering and other raw material feed the kiln tail together, in preheating enters kiln, the coal dust firing temperature is 1400 ℃～1600 ℃ in the kiln, and raw material are burnt to the fritting state, and the residence time is half an hour approximately, bacterium, virus can all be eliminated, the poisonous mineral that retain in the rubbish ash, in high temperature, decompose again, and form new material, indivedual Toxics, as Cr (chromium),, when using at last, do not add water and become concrete with other material generation effect, be solidificated in the concrete, the mankind are not had again what harm.

Claims

1. one kind with city garbage as material, and with the method for dry method preheater kiln cement baking, step is as follows:

1) with the inorganics after the sorting, after removing metal,, at first send into incinerator (1) entirely as cement raw material, burn through make fuel with coal dust, the waste gas that generates enters upright tube through air draft floss hole (2) and gives hot device (3), passes through II level whirlwind tube (4) successively, I level whirlwind tube (5), conditioning tower (6), exhaust blower (7), dust precipitator (8) enters chimney (9), drain into atmosphere, in armamentarium and pipeline that gas passes through, because a large amount of CaO particles is arranged, and the temperature height, active big, route is long, with the toxic gas that waste incineration produces, chlorine, fluorine, the sulphur effect becomes nontoxic CaCl ₂, CaF ₂, and CaSO ₄

2) the above-mentioned rubbish ash that generates in incinerator is delivered to raw material bistrique storehouse (10) and cement bistrique storehouse (11) respectively; Deliver to the rubbish ash in raw material bistrique storehouse (10), with Wingdale, clay, iron powder cooperates, and through metering, sends into dry method raw material mill (12), the additional proportion of rubbish ash, be 20～60% by weight,, change the aforementioned proportion scope according to the raw ingredients requirement, deliver to air lift mud pump (13) through the raw material powder of grinding, then, enter worker's level whirlwind tube (5) successively, II level whirlwind tube (4) and shaft preheater (3), deliver to rotary kiln (14) at last, in kiln, burn till grog through 1400 ℃～1600 ℃, flow into cooler (15), send into cement bistrique storehouse (16) at last.

3) cement clinker that burns till is added proper amount of gypsum and from 5～15% the rubbish ash that incinerator (1) is sent here, is mixed into cement grinding mill (22) and wears into cement through metering;

4) fuel system: raw coal is delivered to coal mill bistrique storehouse (17), feeding coal mill (18), the coal-grinding powder that produces coal is delivered to Pulverized Coal Bin (19), and wherein a part is calcined the rubbish ash in feeding machine (20) feeding incinerator (1), and another part is calcine cement in feeding machine (21) feeding rotary kiln.