Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Chemical Engineering

Today, energy management is the main target of most industries due to the shortage in nonrenewable energy resources. In this context, heat of waste streams is utilized to decrease fuel cost and increase energy efficiency. Since cement industry is considered one of the highest energy consuming industries in Egypt, thus any waste heat recovery will have a great effect on the industry energy cost. In the present work an actual cement plant was studied where all available waste heat streams were checked and streams with the highest energy content were selected and used as energy sources. Waste heat recovery process was then designed with the aim of reaching the most efficient method for heat extraction. The utilization of the extracted heat in power generation, pet-coke and RDF drying was considered. Results showed that using waste heat to generate steam to be used in steam turbines resulted in a decrease in cement production cost in addition to the production of enough energy to be used in plant extension or any other project. A second proposal was the use of the waste heat in heating fresh air to be used in drying pet-coke. Pet-coke is considered the main cement industry fuel. Pet-coke is originally dried using hot gases produced by a hot gas generator 2HGG3 which uses heavy fuel oil. The generator faces a lot of operation and maintenance problems. Finally the waste heat was used to dry Refused Derived Fuel 2RDF3 which is considered the main used Alternative Fuel 2AF3 and contains a considerably high moisture content especially in winter. A process was designed for each scenario and an economic study was presented to evaluate the needed capital cost, operating cost and pay-back period

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