Pressure-drops control strategy in a fixed-bed reactor

This paper presents a strategy to control pressure-drops (head lass) in a b iofilter designed according to the "Mist-Foam" concept. This concept is bas ed on the mixing of the gaseous substrate and a liquid nutrient solution wi th an atomization nozzle to generate a mist passing subsequently through a synthetic polyurethane foam. In this type of bioreactor, the microbial grow th reduces progressively the empty bed volume of the biofilter and causes a n increase in the pressure-drops. This phenomenon can result in a complete clogging of the biofilter. The strategy of pressure-drops control presented here consists of successive interruption of the liquid flow, automatically controlled, resulting in a drying effect of the biomass. Tested during a 1 60 days experiment, this system has permitted to reduce and stabilize the p ressure-drops in a biofilter in which the carrier exhibited a high likeliho od of clogging. (C) 2001 Published by Elsevier Science B.V.