A STAGED FLUID BED CONTACTOR FOR THE ECONOMIC THERMAL DESTRUCTION OF TOXIC CHEMICALS ON SOILS

THE COST FOR REMOVING TOXIC CHEMICALS FROM THE SOIL WITH PRESENT TECHNOLOGY IS ENORMOUS, IN SOME CASES, POPULATIONS THE COST FOR REMOVING TOXIC CHEMICALS FROM THE SOIL WITH PRESENT TECHNOLOGY IS ENORMOUS. IN SOME CASES, POPULATIONS MUST BE RELOCATED AND MANY ACRE-FEET OF SOIL MUST BE EXCAVA-TED AND TREATED OR STORED IN "SAFE" STORAGE FACILITIES. IM-PROVED TECHNOLOGY IS NEEDED TO REDUCE CLEAN-UP COSTS. ULTIMATE REMOVAL OF TOXIC CHEMICALS SHOULD INVOLVE THEIR CHEMICALS SHOULD INVOLVE THEIR CHEMICAL ALTERATION TO NON- TOXIC SPECIES. HIGH TEMPERATURE OXIDATION (THERMAL DESTRUC TION) IS A KNOWN METHOD FOR ACCOMPLISHING THIS OBJECTIVE. HOWEVER IN THE CASE OF TOXICS ABSORBED ON SOIL IN LOW CON- CENTRATIONS, LARGE AMOUNTS OF SOIL MUST BE HEATED TO HIGH OXIDATION TEMPERATURES (1500 - 2000 DEGREES F) IN ORDER TO INSURE THE DESTRUCTION OF THE TOXIC CHEMICALS. THIS REQUIRELARGE AMOUNTS OF AUXILIARY FUEL TO INCREASE THE ENTHALPY OF THE SOIL MASS, UNLESS ENERGY EFFICIENT THERMAL DESTRUCTION PROCESSES ARE DEVELOPED. THIS PROPOSAL PRESENTS THE CONCEPTOF A STAGED FLUID BED CONTACTOR WHICH IS DESIGNED TO MINI- MIZE FUEL REQUIREMENTS THROUGH EFFECTIVE HEAT RECOVERY WHILESIMULTANEOUSLY PROVIDING THE HIGH TEMPERATURES AND RESIDENCETIMES NEEDED TO INSURE TOXIC BURNOUT. IT IS ANTICIPATED THAT THE SUCCESSFUL COMPLETION OF THIS RE-SEARCH WILL LEAD TO THE COMMERCIALIZATION OF A PROCESS UNIT FOR THE THERMAL DECONTAMINATION OF SOILS AT A COST IN THE RANGE OF $1 PER TON. THE UNIT CAN BE DESIGNED AS A SELF-CONTAINED SYSTEM AND TRANSPORTED TO SITES CONTAINING SOILS CON-TAMINATED WITH TOXIC CHEMICALS. THE SYSTEM OFFERS A LARGE COST SAVINGS OVER CURRENT TECHNOLOGIES AVAILABLE FOR SOIL DECONTAMINATION.