Medium and small-scale the intersection of incinerator and the intersection of waste gas and the intersection of heavy metal and half the universe type treatment technology recommend
The worker grinds institute's environment and security hygiene technological centre of development Researcher Chen MingHui / manager Huang ZhiFeng

Summary
Taiwan is active and frequent day by day because of population's gradual increase and economy, the output of the waste increases year by year too, so it is more important to incinerate France and deal with rubbish decrement. But it causes the public hazards question of the secondary pollution to incinerate the law, especially the toxic material of trace in the waste gas, strong poison and difficult characteristic that remove its, make, know his control technique become the modern important subject in environment protecting mode. Worker grind institute can money accept in environment protecting mode administration trust, devoted to half the universe the intersection of processing system and the intersection of localization and technological development and popularize for many years, it is quite complete that it has already studied to the control of the sour gas, dust in the waste gas that it is early, half the universe type handle system pair deacidify efficiency more than 90% already and dusting more than 99%. This plan applies half a the universe type processing system to the incinerator waste gas poisoning material and controls technological development again, set up the control technique of incinerator waste gas heavy metal pollutant of localization, various pollutants remove efficiency:

(1)Acid gas SO2> 90%, HCl> 95%;
(2)Heavy metal pollutant (lead) >99%;
(3)Heavy metal pollutant (cadmium) >99%;
(4)Heavy metal pollutant (mercury) >90%;
(5)Particulate contaminant> 99%.

[Key word ]
1.Half a the universe type absorbs the scrubbing system (Semi-dryer Absorption System)
2.Incinerator waste gas (Waste Gas of Incinerator)
3.Heavy metal (Heavy Metal)

First, preface
Incinerating the law can be regarded as the processing method among the optimal waste, not merely reachable volume decrement, purpose that toxicity lowers, also recoverable and useful resources. Only it is in the course of incinerating, the heavy metal that the waste includes, because unable to be heated to decompose destroyed, and volatilize and enter in waste gas, and the heavy metal particle is difficult to be blocked by the control equipment of shot-like particle except that, and disperse in the atmosphere, cause pollution, especially persons who has accumulating toxicity such as lead, cadmium, mercury,etc., can't ignore still more. In the future, it will be a garbage disposal main means to incinerate the law, and the construction of incinerator will have trend of increase, so the heavy metallic handling problem in the waste gas after incinerating, it is the subject needing to study urgently at present.

Second, incinerate the removal mechanism of heavy metal in the waste gas
Generally speaking, proportion is greater than 5 being called the heavy metal. Plastics, rubber, used battery, paint contain the micro- heavy metal in articles, exist in the dust, fly ash, waste gas of bottom after incineration.

Includes the heavy metal supplies via the incineration under the high-temperature environment, will volatilize compatibly in the waste gas. After the waste gas passes cooling equipment and heat recovery boiler, some heavy metal will be removed by the cleaner because of condensing adsorption, as the waste gas heals the the lower through the temperature of the dust-collecting equipment, it is the better to remove the result. This removes the main basis following response organizations of the mechanism:

1. The volatile heavy metal is reduced and reached the saturation because of the temperature, is removed by the cleaner after condensing into a particle.
2. Although heavy metallic element with lower saturation temperature is unable to reach the condition condensed, but can because of catalysis to fly to grey surface, react, form the intersection of saturation temperature and great, relatively apt oxide and chloride that condense, and is removed by the cleaner.
3. The heavy metal existing with the gaseous state, absorb with the activited carbon, is collected and removed with the activited carbon by the dirt collector.
4. Utilize water-solubility of metal chloride, make use of the wet washing way to remove.

The heavy metal of the most difficult treatment can be regarded as mercury at present. It accords with the regulation standard that traditional treatment technology is very difficult, so should do the improvement to the existing equipment, it removes efficiency by ruggedization. The shape that mercury exists in the waste gas mainly has (1) Attitude mercury of element, (2) Mercuric oxide, (3) Three kinds of mercuric chloride. When the waste gas passes the hot recovery plant to lower the temperature to 220 ¡æ, because the incinerator of the rubbish contains HCl of the high thickness, so chlorization has the usually highest mercury content, accounts for 80%, all exist with the gaseous state.

Technology to pour into activited carbon, already in a lot of the intersection of country and application, Switzerland have Zurich, Denmark have Amager and Germany have brands such as Kassel,etc. to produce the relevant apparatus for instance. MWC air pollution of Zurich defends the control equipment, it is the universe type that is absorbed, the electrostatic precipitation adding machine, find under not adding the activited carbon, the reduction of temperature will improve the catching rate of mercury through testing, but efficiency has not exceeded 30%; After adding the activited carbon, remove efficiency to be 90% reachable, find activited carbon person who pour into and mercury remove efficiency have, influence obviously. On average, the heavy metal removes efficiency very above 85%.

Three, half the universe type heavy metal control technique
Half a the universe type scrubs and deacidifies its principle in law utilizes an atomizer (atomizer) ,Diameter absorber turn into slurry fog liquid droplets light of the several dozenth microns,these liquid droplets smalls again with except that acid tower be waited to if you can't last waste gas, keep in touch to be neutralized. Because contact area wide, so quality spread and heat pass efficiency to be good. Spread respect in heat, little liquid droplet temperature rise because of no absorbing heat from waste gas; Spread the respect in the quality, the sour gas passes hydropneumatic interface and absorber function, but the moisture content of small liquid droplet is evaporated gradually because of absorbing the heat. When small liquid droplet reached the bottom of the tower, the moisture contents had already all evaporated and become the powder state of the universe, so there is no problem of waste water treatment.

The powder part of the the universe can be from the bottom dump of the tower, the others are transferred to the postern cleaner to deal with. The dust-collecting equipment is besides removing the dust, Shang Ke makes use of in unreacted absorber and waste gas residual pollutant further react, make treatment effeciency of overall system raise, another inject activited carbon into before dust collection machine, utilize activited carbon adsorptive capacity to absorb and volatilize the heavy metal.

Half a the universe type procedure and processing apparatus of heavy metal dealing (show as in Fig. 1) ,Its processing unit includes: (1)Primary combustion incinerator; (2)Secondary combustion incinerator; (3)The multicell whirlwind separates ' Cool) Device; (4)Lower the temperature in the tower; (5)Except that the acid tower of half a the universe type; (6)The activited carbon is poured into; (7)Dirt collector of bladder type; (8)Windmill; (9)Chimney,etc..

Half a the universe type heavy metal control technique flow block diagram medium and small-scale incinerators of Fig. 1

Fourth, conclusion
Worker grind institute can money accept in environment protecting mode administration trust, devoted to half the universe type localization technological development of processing system, it has been early already to deacidifying in the waste gas, the research of dusting has been complete, the deacidification efficiency of half a the universe type processing system has already been more than 90%; And dusting efficiency is more than 99%. Employ half a the universe type processing system to remove the technological development of heavy metal in the waste gas again today, control obtaining the following conclusions to the heavy metal:

1. Set up the control technique of incinerator waste gas heavy metal pollutant of localization, the control technique procedure of heavy metal: Half a the universe type except that the acid tower + activited carbon + bladder type dust collection machine; The removal efficiency of various pollutants is: (1)Acid gas SO2> 80%, HCl> 95%; (2)Lead> 99%; (3)Cadmium> 99%; (4)Mercury> 90%; (5)Particulate contaminant> 99%.

2. In the heavy metal control technique of half a the universe type, the interpolation of the calcium hydroxide of absorber helps the heavy metal to remove the promotion of efficiency, it is more obvious to especially promote the removing rate to cadmium, chromium. Only for mercury, there is no result dealt with. But add the removal rate that the activited carbon contributes to mercury of heavy metal, reachable 90%.