Industrial solvent recovery by condensing from compressed carrier gas - via expansion engine mechanically driving compressor for loaded carrier gas

摘要

The system comprises compressing a current of carrier gas contg. solvent vapour and then cooling to condense much of the vapour as separable solvent for recovery. The gas with residual solvent vapour is passed through an expansion engine partic. an expansion turbine, to produce mechanical energy. The expanded carrier gas is heated and recycled to pick up more solvent vapour for recovery. The mechanical energy derived from the expansion engine is mechanically transmitted to drive the compressor for carrier gas contg. solvent vapour. The mechanical energy derived from the expansion engine can be supplemented with energy from an external source to drive a single stage of compression. The energy from the expansion engine can be fully employed to drive the first stage of a two or multi-stage compressor. Subsequent stages are then driven by energy from an external source. Pref. the carrier gas is an inert gas, such as nitrogen, or a gas with an oxygen content below the limit which would support combustion of the solvent vapour. The installation is used to recover solvent vapours from industrial processes, partic. from the prodn. of paints and varnishes, adhesives and the chemical cleaning of textiles. A higher recovery rate of solvent is associated with a reduced energy requirement of the operation of the recovery plant.