Heat recovery from gaseous exhaust of pulping mill - using condenser preceded by gas scrubber employing recycled condensate

摘要

In the thermo-mechanical pulping of wood chips in an atmosphere of steam, heat is recovered from the resulting mixt. of vapour, gas and solid particles by condensing at least one of the component vapours, and the condensate is used in a scrubber which precedes the condenser to remove solid particles from the mixture entering the condenser. The solids-condensate mit. is returned to the pulping mill from which the gaseous mixture is extracted. The condensate is sprayed into the scrubber through an atomiser, and collects in the bottom of the scrubber, where the solids are concentrated by flotation before being recycled. This arrangement keeps the condenser clean and corrosion-free, and prevents environmental pollution by removing the solids from the exhaust gases. The heat is the exhaust is almost completely recovered, with almost no loss of pressure in the recycled steam.