Patent ID: 7176341

Claim:
A method of recovering pure naphthalene from a hot crude coke oven gas containing naphthalene, tars, and solid impurities, which comprises the steps of: (a) directly cooling the hot crude coke oven gas to a temperature of about 80° C. to obtain a cooled crude coke oven gas and a liquid phase containing tar and solid impurities; (b) conducting the cooled crude coke oven gas through an electrostatic filter, wherein the electrostatic filter is insulated or heated so that it is operated isothermally, to remove the tar and the solid impurities to obtain a cooled crude coke oven gas with a tar and solid impurities content reduced by 99.99% and containing naphthalene predominantly in the gaseous phase; (c) cooling the crude coke oven gas containing naphthalene predominantly in the gaseous phase from a temperature of about 80° C. to a temperature of about 20° C. so that the naphthalene contained in the cooled crude coke oven gas deposits out as pure crystallized naphthalene; and (d) directly recovering the pure naphthalene.