Application of Disk Aerators to Recarbonation of Alkaline Wastewater from Wet Gasification of Carbide

Abstract

Whenever possible, neutralization of alkaline wastewater should involve low-cost acid. It is conventional to make use of carbonic acid produced via the reaction of carbon dioxide (contained in flue gases) with water according to the following equation: Carbon dioxide content in the flue gas stream varies from 10% to 15%. The flue gas stream may either be passed to the wastewater contained in the recarbonizers, or. enter the scrubbers (which are continually sprayed with wastewater) from the bottom in oountercurrent. The reactors, in which recarbonation occurs, have the ability to expand the contact surface between gaseous and liquid phase. This can be achieved by gas phase dispersion in the liquid phase (bubbling), by liquid phase dispersion in the gas phase (spraying), or by bubbling and spraying, and mixing. These concurrent operations are carried out during motion of the disk aerator (which is a patent claim). The authors describe the functioning of the disk aerator, the composition of the wastewater produced during wet gasification of carbide, the chemistry of recarbonation and decarbonation, and the concept of applying the disk aerator so as to make the wastewater fit for reuse (after suitable neutralization) as feeding water in acetylene generators.

Performance Evaluation of an Oxidation Ditch System with a Disc Aerator

“…The ditch essentially consists of a closed loop, open channel in which liquid circulation and oxygen input are maintained by a mechanical device. The disc aerator described by (Wu, 1995;Gomolka and Gomolka, 1991;Ghaly and Kok, 1986) is an alternative to the brush and paddle wheel rotors which are traditionally used in oxidation ditches (Moulick et al, 2002;Jones et al, 1971). It has certain advantages with regard to foam generation but the oxygenation capacity of an individual disc was reported to be limited and the use of a number of discs on the rotating shaft was suggested in order to allow for a wider range of oxygenation capacities (Drews et al, 1972).…”