Reflux cooler esp. for vinyl chloride polymerisation - has externally corrugated plates with internal vertical ducts for coolant and provides accurate temp. control and high quality prod.

摘要

A reflux cooler for recycled reaction gas associated with highly exothermic reactions in which foam is formed, is intended esp. for the prodn. of PVC. The heat exchange element used comprises plates corrugated or undulating on both sides and containing tubular chambers or cavities; these plates are freely suspended in a housing, a coolant being conducted through the tubular cavities, while the undulations on the external surface run vertically. The plates are pref. Al (at least 99.5% Al content) and are coated with an anti-corrosion coating on their external surfaces. The plates are pref. hung at spacings of 120-180 mm. Used for cooling the recycled gas in the polymerisation of vinyl chloride to provide accurate control of temp. and thus obtain high quality in the end product. By spacing the plates sufficiently far apart, i.e. at 120-180 mm, bridging across of material between adjacent plates is avoided, whereas the corrugated external form partly compensates for the resultant loss of cooling area per vol. Furthermore, the grooves of the corrugations promote the rapid downward flow of the condensate.