Abstract: A two-stage process, and the apparatus for practicing the process, for cooling process gas are disclosed. The process gas is firstly air-cooled by convection to a temperature above the dew point of naphthalene and finally cooled to the desired discharge temperature by heat exchange with a cooling liquid. The condensed portion of the process gas resulting from the first cooling stage may be utilized to flush the gas conduits of the liquid heat exchanger of the second stage, followed by a recirculation of that condensed portion of the coke oven gas either back through the second stage or by introduction into the stream of process gas prior to its introduction into the first cooling stage.

Abstract: A method for cooling naphthalene containing gas streams using recirculated cooling water comprising physically separating suspended naphthalenic solids from the used cooling water, injecting a water immiscible solvent for naphthalene into the clarified cooling water, and vigorously mixing the solvent and cooling water to form a dispersion which is recooled in an indirect heat exchanger without serious buildup of naphthalenic solids in the heat exchanger and recycled to cool the gas stream.