Process for collecting airborne anhydrides

Abstract

An apparatus and process for the recovery of airborne anhydrides such as anhydride vapor or dust wherein these airborne anhydrides are contacted with hot glycol, such as diethylene glycol, in the liquid phase to first dissolve and then react with the airborne anhydrides yielding a useable by-product, such as half-esters. In the preferred embodiment, first airborne anhydrides are introduced at the top of a venturi where the anhydrides are contacted with diethylene glycol of at least 270.degree. F. The airborne anhydrides dissolve in the glycol and then react with the glycol to form a solution of half-esters and glycol. The venturi enhances the contact between the glycol and the first airborne anhydrides, facilitating the dissolution of the anhydrides in the glycol. Second airborne anhydrides are introduced at the discharge side of the venturi such that the second airborne anhydrides dissolve in unreacted hot glycol and then react to form additional half-esters. The solution of half-esters and unreacted glycol then flow into a collection tank from which the solution is circulated back through the system. Any residual airborne anhydrides remaining after the venturi are directed through a packed column. In the packed column, these airborne anhydrides are again contacted with the glycol solution such that the airborne anhydrides dissolve and react to form half-esters.

Dependencies are inferred from the claim text.