CN101732959A

CN101732959A - Method for capturing heavy metal in flue gas

Info

Publication number: CN101732959A
Application number: CN200910248778A
Authority: CN
Inventors: 李润东; 李彦龙; 可欣; 王雷; 孔繁霖
Original assignee: Shenyang Institute of Aeronautical Engineering
Current assignee: Shenyang Institute of Aeronautical Engineering
Priority date: 2009-12-25
Filing date: 2009-12-25
Publication date: 2010-06-16

Abstract

The invention relates to a method for capturing heavy metal in flue gas. The flue gas firstly enters into four continuous liquid absorption bottle, absorbents are 1mol/L HNO3 solution, 10% H2O2 solution, 1mol/L HNO3 solution and 10% H2O2 solution respectively, the liquid absorption bottle absorbs heavy metal in the flue gas and can cause the flue gas to be rapidly cooled, so as to reduce secondary synthesis of dioxin; then the flue gas passes through a flue gas drying bottle, drying agent is silica gel, the drying agent absorbs moisture in flue gas and volatile liquid absorbent, thus avoiding damage on solid absorbent; and finally the flue gas passes through a solid absorption bottle, the absorbent in the bottle is activated carbon, and the activated carbon absorbs residual volatile heavy metal in the flue gas. The invention has the following advantages: heavy metal total capturing efficiency is high, especially in capturing of volatile heavy metal; flue gas is rapidly cooled, thus being beneficial to control of dioxin in melting process; and technological flow is simple and reliable and is easy to operate.

Description

The capture method of heavy metal in a kind of flue gas

Technical field

The present invention relates to a kind of waste treatment method, the capture method of heavy metal in especially a kind of flue gas belongs to hazardous waste and handles the disposal technology field.

Background technology

Along with burning disposal the applying of field of treatment of solid waste such as municipal refuse, clinical waste, hazardous waste, the incineration of refuse flyash generation increases day by day, it is estimated 2007 the end of the year China the incineration of refuse flyash annual production above 500,000 tons.Facts have proved that in the waste incineration process, volatilization heavy metal (comprising Hg, Cd, Pb etc.) of attitude and dioxin pollution thing etc. are enriched on the submicron particles such as flying dust easily.This causes flying ash to contain the high heavy metal of toxicity and the dioxin pollution thing of higher toxic equivalent of leaching, so flying ash is regarded as belonging to hazardous waste and must specially treated be allowed for access ecological environment usually.

The curing control technology of heavy metal contaminants mainly contains melting and solidification, cement solidification, chemical stabilization and acid or other solvent extraction methodes in the flying ash.The high-temperature fusion facture is present important a kind of flyash treatment method for waste incineration, promptly under high-temperature situation, make fusing fly ash, become stable glassy state slag after the cooling, and destroy organic principle such as dioxin, in the glassy state slag, make it can stripping most of heavy metals immobilization, but at high temperature also highly volatile enter in the fusion flue gas volatile heavy metal (Hg, Pb, Cd and Cu etc.).How with the volatile heavy metals trapping in the fusion flue gas to not making it enter that contaminated environment also is a key issue of melt process technology in the atmosphere.

At present, the heavy metal in the flying ash melt process flue gas generally adopts sack cleaner to capture, and the method is not high to volatile heavy metals trapping efficient, and general to the control effect of bioxin in the flying ash melt process.So develop the capture method of heavy metal in the incineration flue gas efficiently practical significance is significantly arranged.

Summary of the invention

The object of the present invention is to provide a kind of method that is used for flying ash fusion flue gas heavy metals trapping.This method can obviously improve the arresting efficiency of volatile heavy metal in the flying ash flue gas, helps the control of flying ash melting process De bioxin simultaneously.

For achieving the above object, the technical solution used in the present invention is: the capture method of heavy metal in a kind of flue gas, flue gas at first enter continuous four liquid absorption bottles, and absorbent is respectively the HNO of 1mol/L ₃Solution, 10% H ₂O ₂Solution, the HNO of 1mol/L ₃Solution, 10% H ₂O ₂Solution, the liquid absorption bottle absorbs heavy metal in the flue gas, can make the flue gas fast cooling simultaneously, and the secondary that reduces bioxin is synthetic; By the flue gas drying bottle, drier is a silica gel then, and the moisture in the drier absorption flue gas and the liquid-absorbant of volatilization are avoided its destruction to solid absorbent; By the solid absorption bottle, the adsorbent of interior dress is an active carbon, by remaining volatilization heavy metal in the charcoal absorption flue gas at last.

The present invention has the following advantages:

1. heavy metal total arresting efficiency height is particularly to the capture of volatile heavy metal;

2. flue gas cools off fast, helps control of dioxin in melting process;

3. technological process is simple and reliable, and is easy to operate.

Description of drawings:

Fig. 1 is the connection diagram of the used absorption plant of the present invention.

Be masked as among the figure: the 1-gas cylinder; The 2-flowmeter; The 3-cabinet-type electric furnace; The 4-quartz reactor; The 5-corundum crucible; The 6-water tank; 7-liquid absorption bottle; 8-flue gas drying bottle; 9-solid absorption bottle.

The specific embodiment:

Consult Fig. 1, the present invention is an example with vertical box high-temperature tubular resistance furnace 3 melting incinerating flying dust flue gases.Fusion atmosphere is nitrogen, is provided by nitrogen cylinder 1, and by flowmeter 2 controlled atmospher flows, flying ash is held by corundum crucible 5, high-temperature fusion in quartz reactor 4, and the fusion flue gas feeds to capture in the heavy metals trapping device and reclaims.The fusion flue gas is successively by four liquid absorption bottles 7, flue gas drying bottle 8 and solid absorption bottles 9, and the flue gas by trapping system can discharge.Four liquid absorption bottles 7 and flue gas drying bottle 8 are placed in the tank 6, are lowered the temperature by cold water.

Embodiment 1

Get flying ash 5g and put into corundum crucible 4, the atmosphere flow is made as 0.5L/min, and resistance furnace 5 temperature are made as 1000 ℃, and flying ash is carried out the melt process of 30min, and flue gas feeds the heavy metals trapping system.After experiment finishes, adopt rare HNO of 3% ₃Solution cleans quartz reactor, takes out a small amount of washing lotion, flying ash, flying dust slag and each adsorbent and carries out the analysis of content of beary metal, calculates the heavy metals trapping efficient of heavy metals trapping system.Found that: the arresting efficiency of volatile heavy metal Pb and Cd is respectively 88% and 93%, and the arresting efficiency of medium volatilization heavy metal Cu and Zn is especially up to 93% and 94%.

Embodiment 2

Get flying ash 5g and put into corundum crucible 4, the atmosphere flow is made as 0.5L/min, and resistance furnace 5 temperature are made as 1100 ℃, and flying ash is carried out the melt process of 1h, and flue gas feeds the heavy metals trapping system.After experiment finishes, adopt rare HNO of 3% ₃Solution cleans quartz reactor, takes out a small amount of washing lotion, flying ash, flying dust slag and each adsorbent and carries out the analysis of content of beary metal, calculates the heavy metals trapping efficient of heavy metals trapping system.Found that: the arresting efficiency of volatile heavy metal Pb and Cd is respectively 76% and 83%, the arresting efficiency difference 83% and 84% of medium volatilization heavy metal Cu and Zn.

Embodiment 3

Get flying ash 5g and put into corundum crucible 4, the atmosphere flow is made as 0.5L/min, and resistance furnace 5 temperature are made as 900 ℃, and flying ash is carried out the 30min melt process, and flue gas feeds the heavy metals trapping system.After experiment finishes, adopt rare HNO of 3% ₃Solution cleans quartz reactor, takes out a small amount of washing lotion, flying ash, flying dust slag and each adsorbent and carries out the analysis of content of beary metal, calculates the heavy metals trapping efficient of heavy metals trapping system.Found that: the arresting efficiency of volatile heavy metal Pb and Cd is respectively 90% and 97%, and the arresting efficiency of medium volatilization heavy metal Cu and Zn is respectively 92% and 91%.

Claims

1. the capture method of heavy metal in the flue gas, it is characterized in that: flue gas at first enters continuous four liquid absorption bottles, and absorbent is respectively the HNO of 1mol/L ₃Solution, 10% H ₂O ₂Solution, the HNO of 1mol/L ₃Solution, 10% H ₂O ₂Solution; By the flue gas drying bottle, drier is a silica gel then; By the solid absorption bottle, the adsorbent of interior dress is an active carbon at last.