Chlorine bypass system for stable kiln operation and the recycling of waste

The cement industry in Japan has been promoting the recycling of waste as alternative fuels or raw materials with the object of environmental preservation and resource conservation. Consequently, as the amount of waste recycled has increased, so has the amount of volatile components, in particular, chlorine. Therefore, there has been a need for technology to remove chlorine effectively from kiln-preheater systems. The authors have developed a new chlorine bypass system to meet this need. Outlines and technical points of the chlorine bypass system such as its structures and tasks, effective chlorine removal at a low bypass ratio and the attainment of dust free operation by adding bypass dust to cement etc., are summarized. Furthermore, the computational fluid dynamics technology is used to evaluate the cooling performance of the probe, which is an important factor in design. The representative operation data such as volatile components balance, heavy metals balance and chemical components of bypass dust are summarized. Finally, as a design for the recycling of chlorine-containing wastes, the chlorine balance estimation in the case of using incineration residue of municipal refuse as cement raw materials is mentioned.