Formaldehyde

Abstract

Recycle and fresh methanol are vapourised and mixed with air, and superheated to 100oC-l30oC. Hot gases pass to the converter after mixing with by-pass air and steam. The converter contains granules of silver catalyst supported in a copper basket. Partial condensation takes place in a gas cooler and the mixture of condensate and uncondensed gas is pumped to the bottom of an absorber. The remaining gas is finally scrubbed in the top tray section using the balance of process water required for the 'synthesis product'• This is the name given to the liquor removed from the base of the absorber. For 37 percent HCHO/3 percent CHSOH, the synthesis product is the final product. For a higher concentration however, of SO percent HCHO/O.S percent CH30H, the products need to be distilled.