Energy audit for pyro-processing unit of a new generation cement plant and feasibility study for recovering waste heat: A case study

摘要

In this work, firstly the energy audit was performed on the pyro-processing unit of a cement plant in Iran to improve the efficiency of the clinker production process and operating the system. In this plant, fuel combustion is the main source of thermal energy due to generation about 94% of the total heat input energy of system that it used for the clinker production process. The results indicated about 50% of total heat input was consumed for the clinker formation and 48% of it was lost in the form of radiation from the shell of the kiln, grate cooler, preheater, and convection along with exhaust gases from the pyroprocessing unit. Also, the thermal efficiency of the pyro-processing unit was 50% that is in the range of modern plants thermal efficiency (50-54%). Secondly, according to the obtained data, the potential of electrical energy production from the exhaust gases of preheater and grate cooler was evaluated through the waste heat recovery power generation (WHRPG) unit. It was found that about 5.2 MWh power can be produced in WHRPG unit. Finally, the economic feasibility showed that the time of return of capital could be about 6.7 years. (C) 2019 Elsevier Ltd. All rights reserved.