A Case Study of Waste Minimization by Process Change in Magnetic Tape Manufacture

SUMMARY The manufacture of magnetic tape commonly requires the use of large amounts of mixed solvents that must be evaporated and then collected. The most widely used method for controlling the solvent emissions from the coating line is carbon adsorption. The solvent is recovered from the carbon by steam injection into the solent-laden bed, condensation of the water-vapor mixture, and separation of the condensed solvent from the water by decantation. The water must be treated before discharge and the spent carbon poses a waste disposal problem. This paper discusses a solvent recovery system based on direct vapor condensation that eliminates the wastewater treatment and solid waste disposal problems. The installed solvent recovery system has performed at and above the NSPS requirements. Innovative design changes offer even greater potential.