Re: GAS-L: Dechlorinated char

[LINVENT@aol.com]

In a message dated 9/26/02 5:42:20 PM, hseaver@cybershamanix.com writes:

<<   What about heavy metals? I've been very interested in gasification of
biosolids (locally you can get paid to take them *and* free delivery, all nice
and dry) and the question of heavy metals immediately arose. I'd think that 
MSW
would also contain a fair amount of heavy metals, perhaps even more. Of 
course,
if so, one might look at it as a way of concentrating them if they aren't
destroyed or chemically nullified, possibly a resource for recycling? 


-- 
Harmon Seaver    >>

Dear Harmon,
    Heavy metals are limited in their evolution from a gasification system by 
the reactor output temperature. If evolved from the reactor, the cleaning 
system gas temperature is low enough, they form aerosols which are then 
removed in the gas cleaning system. 
    Mercury is one which may leave traces of vapor even with lowered gas 
temperature. There are new methods of removing mercury, but even activated 
charcoal is more applicable to gasification systems than combustion as the 
volumes of gas are less. 
    If calcium or other alkali metals are present in the feed which is often 
the case, the metals form solid stable compounds with these and are not 
evaporated. These are discharged in the ash. 
    None of the materials which we have run through the system have ever had 
any tclp issues. 
    An interesting aspect of gasification is the feasibility and technical 
superiority for conversion of radionuclide bearing wastes. Because the volume 
of gas is low and there are not many radionuclides which wiil vaporize at 
gasification temperatures, the DOE has a group exploring this area of 
endeavor as an alternative to incineration. 
    

Leland T. Taylor
President
Thermogenics Inc. 
7100-F 2nd St. NW Albuquerque, New Mexico USA 87107 Phone: 505-761-5633, fax: 
341-0424, website: thermogenics.com. 
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