Mitsubishi Jukogyo Kabushiki Kaisha

Nippon Kokan

Toshiya Oyamoto

Katsuaki Makino

Shingo Kurisu

Setumi Ochiai

Fumio Ogawara

Hiromu Miyamoto

A process for recovering heat from a tar-containing gas while simultaneously cooling the gas in a 3-stage cooling step by (1) directing a tar-containing gas through a jet cooler comprising a bed of solid particles so that the gas contacts the solid particles and forms a fluidized bed with the flow of the tar-containing gas, which jet cooler comprises a central draft tube into which the gas is directed and indirect heat exchange lines containing a liquid coolant therein disposed inside the central draft tube and wherein the gas and solid particles are cooled by such indirect heat exchange lines such that the tar from the gas condenses on the solid particles; (2) directing the gas through a tar cooler in the second stage wherein the gas-containing residual tars and other impurities resulting from the treatment in the jet cooler are sprayed with a circulating tar from a nozzle to remove a residual tars and impurities from the gas and wherein the gas is further cooled in said tar cooler by means of an indirect heat exchange unit containing a liquid coolant therein; and (3) further cooling the gas by introducing the thus-treated gas into an indirect heat exchange unit wherein the gas is further cooled with lines carrying a liquid cooling medium and the gas finally sprayed with a light-gravity tar to remove the remainder of tar and other impurities from the gas. By the aforementioned method, heat is recovered from the gas by the liquid coolants, etc., used in the cooling stages.

Process for recovering heat of a tar-containing high-temperature gas

Waste material heated in the bottom of a thermal decomposition furnace is vaporized to create gas flow upwardly within the furnace. Cooling means located to have the upwardly flowing gas pass thereacross operates to control the temperature of the gas leaving the furnace through the upper end thereof so that gaseous product having a boiling point above the boiling point induced by the cooling means will condense and fall within the furnace onto tray means located below the cooling means and adapted to receive therein condensed liquid from the cooling means. The tray means include orifice means for enabling upwardly flowing gas to come into contact with the liquid received in the tray means, and downflow tubes for causing liquid within the tray means to flow downwardly to the bottom of the furnace into contact with heating means. Gas flowing upwardly from the heating means passes through the orifice means and into contact with the liquid in the tray means. By adjustment of the temperature of the cooling means above the tray means, exit gas flow is controlled to prevent clogging of the exhaust portions of the apparatus by solidification of the decomposition product.

Thermal decomposition apparatus

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Hiroshima, Japan

Toshiya Oyamoto