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An experiment on drying and dechlorinating refuse derived fuel (RDF) using superheated steam was carried out and compared with a simple heat and mass transfer model in order to examine the behavior of organic chlorine thermal decomposition in municipal solid waste (MSW). The heat transfer and drying model consists of three parts : a steam condensation period, a constant rate drying period and a decreasing drying period. Either the water content or the temperature of the sample was predicted successfully using the other experimental value. Sample temperatures reached almost the same temperature as 473 K superheated steam after about 30 min at the 473 K superheated steam temperature, or about 15 min at a 523 K temperature. The rate of water content decrease accelerated with the increase in superheated steam temperature. The developed drying model enabled us to predict time-dependent changes in the sample temperature or in the sample water content.About 90% of the organic chlorine was decomposed in about 60 min in 523 K superheated steam. The lower heating value decreased with the decrease in the dry yield, because decomposition of the sample resulted in decreases in carbon and hydrogen along with chlorine.

With a goal to develop a suitable refuse derived fuel (RDF) manufacturing process, organic and inorganic chlorine removal from RDF was investigated by using steam with various temperatures. For organic chlorine pyrolysis, steam temperature was changed from 463 to 573 K. For inorganic chlorine removal by steam condensation, steam temperature was fixed at 373 K. The pyrolysis kinetics of organic chlorine increased with an increase in superheated steam temperature, whereas the chlorine emission kinetics increased with an increase in sample temperature. Part of the pyrolyzed organic chlorine changed to inorganic chlorine. Organic chlorine decreased more rapidly than a decrease in dry matter yield, but inorganic chlorine increased with a decrease in dry matter yield above 0.8, which indicated that the decreasing ratio of total chlorine was roughly as large as that of dry matter yield. Removal ratio of inorganic chlorine increased with an increase in steam condensation because inorganic chlorine was dissolved in a water droplet.