Dangerous trash (danger of the following abbreviation is useless) difference of complex, area spends phyletic and various, part serious, handle undeserved meeting to bring a series of the people's livelihood and social issue. Carry out a proof, high temperature burns is the efficient way that highs to useless safety deals with and decrease a look to change, among them rotary kiln burns craft is danger it is effective in useless processing deal with one of craft, have processing to high useless sort is much, treating capacity is large wait for an advantage. Our country from 20 centuries 90 time, begin to use rotary kiln to burn stage by stage systematic processing danger is useless. In recent years, because fireproof material mars the accident stopping kiln that cause to have more,happen, affected danger badly to abandon burn the steady movement rate of product line, design of fireproof to useless incinerator of rotary kiln danger liner is optimized and efficient move etc raised pressing requirement.
1, our country dangerous trash is harmless change deal with the current situation
The danger of our country is useless deal with to begin to start from 1990, to 1996 preliminary form relevant management system, till just was formed 2008 " national danger abandons directory " , 2013, two tall judicatory explain, "Discharge illegally, dump, processing danger of 3 tons of above is useless will enter punishment " , danger of our country be regardinged as abandons the crucial point that processing industry starts. 2016 first half of the year, " action of soil contamination prevention and cure plans " , " directory of national danger trash (2016 edition) " wait for danger to abandon those who handle relevant and special program to be promulgated in succession carry out, 2017, " " 935 " program of work of nucleus of delve of superintend and director of management of standardization of countrywide dangerous trash " promulgate, 2018, zoology environment ministry is begun " clear useless action 2018 " ministry of letter of plan, industry begins economy of the Yangtse River to take industrial green to expand the operation, on November 12, 2019, general office of zoology environment department is released " dangerous trash burns pollution controls a standard (ask for an opinion 2 times to stalk of grain) " , on March 10, 2020, national level " technology of production of processing of solid trash vitrification asks (ask for an opinion to stalk of grain) " ask for an opinion publicly to wait, all make danger useless handle industry development to carry fast, farther catalysis danger abandons processing industry to expand opportunity.
As industrial development, the danger that manufacturing process discharges is abandoned increasingly grow in quantity. 2016, 214 big, medium capacity of useless generation of urban industry danger amounts to thirty-three million four hundred and forty-six thousand tons, among them, 45.3% what industrial danger abandons integrated benefit dosage to occupy gross of benefit good buy, deal with, keep in storage is occupied respectively than 43.8% with 10.9% , be used effectively and dealing with is the main approach that processing industry danger abandons. 2018, 200 big, medium capacity of useless generation of urban industry danger amounts to 46.43 million tons, predict 2020 because of epidemic situation reason, danger is useless will add reach nearly 100 million tons.
2, our country danger is useless burn technology
Carry out a proof, rotary kiln or cement kiln burn processing technology can be handled the industrial danger of gentle system condition abandons solid, liquid, it is to handle danger now to abandon relatively extensive deal with technology. Up to in July 2019, the cement kiln that our country already obtained danger to abandon business certificate deals with in coordination project 75 (do not include area of Hong Kong, Macao and Taiwan) , approve dimensions four million six hundred and twenty-five thousand two hundred tons. At present cement kiln handles danger to abandon in coordination basically include solid to high useless, waste liquid and RDF replace fuel to wait, main from intake air heater, decompose furnace, hind the place processing such as kiln mouth and kiln head cover, fill with the tradition bury, the processing means photograph that burn is compared, cement kiln deals with in coordination litter is having clear advantage, but because start late, technology, operation, superintend the systematic compose that waits for many sided to build still diseased. Accuse as a result of cement craft and product quality canal strict with each passing day, a lot of danger are useless prohibit dealing with in coordination in cement kiln, and after danger abandons processing, be opposite in coordination share of group of composition of operation operating mode, flue gas, stock causes very big change and wave motion, aggravate cement kiln cylindrical shell is corroded and the knot inside the system is encircled or knot skin, shortened fireproof material service life, affected cement kiln badly to grow periodic stability to move.
Rotary kiln incinerator is professional danger abandons an incinerator, main body equipment by rotary kiln, 2 light room, more than heat boiler, urgent cold tower, de-acidification, remove dust the system is formed. The of all kinds high that passes pretreatment is useless enter combustion system through different feed means, rotate of gravity and rotary kiln continuously in oneself below action, stock and combustion air are contacted adequately, complete dry, aerification and combustion process, grey broken bits of Leng Cheng of temper by dipping in water of last remain part.
According to heat vital energy and solid flow direction different, or the position of the burner in rotary kiln, rotary kiln incinerator can be divided to be mixed upstream direct current two kinds of forms. Among them, burner heat source is in of rotary kiln into makings end, solid and flue gas trend are same, make direct current type; Conversely, burner heat source is in a makings end, solid and flue gas trend are reverse, call refluent type. Danger is at present useless burn the system basically is with direct current type the design of rotary kiln is given priority to, refluent type rotary kiln more apply to moisture content the danger with tall or low calorific value is useless etc. Rotary kiln incinerator has applicability wide characteristic, the danger that can handle solid, liquid and gas at the same time is useless. Environmental protection asks strict with each passing day situation falls, professional rotary kiln highs useless incinerator advantage is clear. According to statistic, danger abandons our country rotary kiln burn the system has 800 processing product line about, processing capability differs to 120t/d from 20t/d. Our country danger is useless 2018 burn deal with produce can dimensions achieves 6.16 million T/ year, rotary kiln of course of study of its technical secondary school burns occupy than 53% , basically distributing in and other places of Zhejiang, Jiangsu, Shandong, Heibei, Fujian.
3, fireproof liner designs useless incinerator of rotary kiln danger
1) rotary kiln noumenon
Very crucial equipment is rotary kiln incinerator namely rotary kiln noumenon, because its are equipment of a kind of dynamic movement, taller to requirement of liner structure design, want to ensure fireproof liner runs the stability of next integral liner in condition of dynamic high temperature above all, prevent firebrick to drop the issue such as brick, ballot. system of useless to danger rotary kiln, because rotate speed is slower, be in commonly 1 turn / cent is the following, can be designed according to workshop and brick of monolayer of energy-saving requirement choice, double deck brick, compound brick and whole are pouring wait for different structure, rotary kiln is fireproof material total ply is 250~300mm differs commonly, work among them qualitative common ground treats a firebrick capable person useless sort of temperature and danger is different, can choose tall aluminium corundum Mo Laishi is qualitative, qualitative and chromic zirconium corundum is qualitative fireproof material. When using structure of ply 230~300mm monolayer, be in mostly as a result of fireproof material coefficient of thermal conductivity 1.7~2.0 above, temperature of the wall outside kiln of area of later period high temperature achieves 350 ℃ above, but integral structure is stable, agree with the project that rotary kiln is outdoor.
Use adiabatic brick and structure of firebrick double deck, because of adiabatic brick coefficient of thermal conductivity is low, can rise to reduce effect of kiln skin temperature, temperature of the wall outside kiln can be controlled control in 220 ℃ the following even, energy-saving effect is good, but taller to construction demand, agree with indoor project. Here should notice adiabatic brick intensity asks to be more than 20MPa commonly, adiabatic brick ply is designed cannot under 50mm.
Want to achieve the stability of monolayer brick already, want temperature of the wall outside reducing again, can design compound brick, namely working surface is corundum brick, chromic corundum brick, the reverse side is hollow ball, tall aluminium perhaps sticks alumina earthy, thermal insulation ply is 50~70mm about. Efficiency of production of this kind of product is low, and because working layer and thermal insulation material are qualitative hot coefficient of expansion and agglomeration shrinkage are different, accordingly, micro-crack arises easily in joint, percent defective is taller.
Sketch map 1
In view of this, can use design of groove compound brick, working layer material is qualitative changeless, the rear opens offer of the fill after groove the heat insulating materials such as rice board. Brick of this kind of groove compound brick, be produced not only and construction is convenient, and can obtain ℃ of 30~50 of temperature of the wall outside dropping cylindrical shell to control the effect.
Sketch map 2
Additional, partial rotary kiln is used pledge gently pouring expect or beaverboard as separate stuff, working layer is used pledge again pouring makings (the metal pays the firm that nail anchor) double deck is pouring structure, temperature of the wall outside rotary kiln of OK and reasonable control. This structure uses a metal a fireproof material and cylindrical shell are an organic whole repeatedly, nonexistent firebrick falls off problem, but metal solder quality and pouring eduction of drying of portion of the water in makings is crucial.
Be compared and character, firebrick plan is overhauled and change convenient, suffer environment and factitious element effect lesser. Build project rotary kiln now basic it is the design outdoor, as carry produce and environmental protection requirement, it is better to introduce monolayer structure stability, high temperature area can consider groove compound brick means, temperature of the wall outside reducing. And from anticorrosion angle, control of temperature of the wall outside cylindrical shell is in 160~320 ℃ interval, more reasonable.
2) 2 light room
Sketch map 3
2 light the room is main the function is right flue gas undertakes 2 times burning handling, can light component, flying ash grain and 2 flower etc burn decompose, physics and chemical reaction exist at the same time, reaction is severe. 2 light the room is average include fireproof material, insulation material and heat insulating materials. Among them, fireproof material is to show working layer pledges again pouring makings, but plastic or firebrick, insulation material is to show heat preservation is pouring makings and heat preservation brick, heat insulating materials is to point to beaverboard of siliceous calcareous plate, pottery and porcelain and accept rice board. At present 2 light indoor line
The design basically includes 3 kinds of kind:
(1) plan one: Include fireproof material, insulation material and heat insulating materials; Structure of this kind of three-layer is designed, it is with total ply 450mm exemple, mural temperature is 80~90 ℃ outside.
(2) plan 2: Include fireproof material and insulation material. Temperature of the wall outside this structure is higher, with 305mm always thick for exemple, temperature achieves 150~180 ℃ .
(3) plan 3: Include fireproof material and heat insulating materials. This kind of plan uprights between before two kinds of plan, with 270mm always thick for exemple, mural temperature is 110~140 ℃ about outside.
Generally speaking, 2 light room temperature to be 1100~1200 ℃ about, local temperature achieves burner even 1300 ℃ above, so working layer chooses corundum Mo Laishi to be able to satisfy use requirement character, use corundum of proposal of layer of burner area job pledges or chromic corundum pledges material. Be compared and character, the three-layer structure of one devises plan stability is good, not easy because of flat perhaps string together fire, bring about cylindrical shell to high temperature is corroded or overheating is out of shape and stop furnace overhaul.
3) other position
Part of more than heat boiler basically is ash bucket, header, coping sealed and exit flue needs to use partial wear-resisting pouring makings, among them ash bucket uses heat insulating materials and wear-resisting pouring result of makings double deck is more, total ply is in commonly 200~250mm.
Urgent cold tower is used acid-proof and pouring expect or acid-proof puddle, coping makes an appointment with temperature of 2 meters of area to be able to serve as thermal insulation in order to use 25mm heat insulating materials higher downward, 100mm of liner total ply can.
4, danger useless craft and fireproof data design optimize typical rotary kiln
Suggest to discover according to spot survey, fireproof material mars main concentration at area of rotary kiln noumenon. Danger is useless burn basically include the following kinds of models to handle technology, be aimed at this, put forward the following design to optimize a proposal.
1) expensive stock of processing moisture content
Moisture content of the stock that enter pit is high, into makings end fireproof material heat flakes serious, the Molaishi with thermal shock good stability Mo Laishi of qualitative, corundum corundum carborundum is qualitative, qualitative wait for fireproof material to apply to this area.
2) treating capacity of kiln head waste liquid big, pulverization is bad
General kiln head handles waste liquid through pulverization gun, burn area basically is in dry paragraph, when sufferring equipment to if pulverization result is bad,be affected, this area is fireproof data also can appear flake mar, qualitative, corundum not comes to Mo Laishi simple stuff of carborundum of qualitative, corundum applies to stone likewise this. When moving, should increase frequency of examination pulverization equipment commonly second, it is advisable that at the same time waste liquid treating capacity does not exceed 30% .
3) iron sheet (bucket) wait to expect treating capacity is large forcedly
The stock hardness such as metal pail is big, rotary kiln rotate speed is slow, stock rotates repeatedly inside kiln cause into makings area mechanical wear is serious. Choice intensity the corundum carborundum with tall, better wearability pledges fireproof material uses the effect good.
4) contain salt of low melting point to measure expensive stock
After stock contains quantity of salt of K, Na to be more than 5% above, melting point is inferior, form high temperature easily slaggy, permeate to fireproof material, erode serious. When occurrence high temperature is slaggy, fireproof material chooses high temperature area chromic zirconium corundum is qualitative relatively appropriate, general Cr203 content differs for 3~10% .
5) the stock with the high volume that contain fluorine
Fluorine proportion is contained in stock taller, when amounting to 1~4% , as a result of the Si in F and fireproof material very easy reaction forms SiF4 aerification, cause liner matrix structure to destroy, erode quickly; The matter content in wanting to dominate fireproof data strictly especially content of 2 oxidation silicon, use Cr203 content to be material of 9~15% chromic corundum, OK and contented rotary kiln runs need normally.
5, last word
Danger is abandoned burning is burgeoning domain, high among them useless sort is complex and various, difference of content sex, calorific value is bigger, rotary kiln and 2 light indoor line basis to need, design formal diversity. As the country useless to danger superintendency strength is increased, large rotary kiln burns technical general receives wider application in danger useless processing, type selecting of fireproof to rotary kiln incinerator material and design posed a challenge. Compare with photograph of furnace of kiln of traditional high temperature, fireproof material researcher should characteristic of character of makings of trash of more attention danger, operating mode (burn composition of temperature, flue gas) etc.
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