Design and Implementation of Energy Recovery System from Autoclaves in Fiber Cement Industry

Abstract

The fiber cement composite process has extremely high fuel consumption and a lot of waste energy released. This study focuses on the recovery methods from two waste heat streams; the condensate and the exhaust steam from the autoclaves. An analysis of the heat loss from the autoclave shell showed that the optimum insulation thickness is 0.085 mm. To recover heat from either condensate or exhaust steams, a pinch location can recover the waste heat for fresh boiler feed water at 100°C. Introduction of multiple heat exchanger optimization and control proposed two series of shell and tube exchangers for the condensate and the exhaust steams. The fuel consumption from the heat recovery can approximately be reduced to 8.37 MTHB/year with a payback period of one and a half year.