Moving the goal posts
Although the cement industry increasingly uses alternative fuels such as refuse-derived fuel (RDF), biomass and sewage, the high water content of these fuels places a ceiling on their maximum share in a cement plant’s fuel mix. However, economical drying technology can extend the contribution of such fuels and move the goal posts in alternative fuel use. By Tema Process BV, The Netherlands.
The high water content of waste streams such as refuse-derived fuel (RDF), biomass and sewage sludge often limits their use as alternative fuel in cement kilns. By evaporating the water contained in these fuels before combustion, a larger fraction becomes suitable for use.
Dutch dryer specialist Tema Process BV has developed a fluid bed dryer that enables cement works to use the waste heat from the clinker cooler as an economical means to dry such fuels. The exhaust gas, which usually has a temperature ranging between 120-250°C, can be directly applied in the fluid bed dryer or via a hot water circuit if large distances have to be bridged.