A case study: The waste heat recovery and utilization for power generation in a cement plant (Phase-1)

Cement production is one of the most energy intensive industrial processes. A considerable amount of the energy input is lost through different parts of the processing units such as pre-heater stack, rotary kiln shell and clinker cooler stack. The recovery and utilization of waste heat not only conserves fuel, usually fossil fuel, but also reduces the amount of waste heat and greenhouse gases dumped to the environment. Several different medium-temperature waste heat power generation for cement production have been developed in the past years, including the Steam Rankine Cycle, the Organic Rankine Cycle and the Kalina Cycle. The Steam Rankine Cycle approach is the common approach that used in many plants. The Organic Rankine Cycle and the Kalian Cycle are not widely used in commercial applications in cement plant. The aim of this case study was generating power by utilizing waste heat from the dual sources using Steam Rankine Cycle. In the present work a WHRPG system is designed to recover waste heat for power generation purpose in the cement manufacturing process. Waste gas from the pre-heater with amount of 440, 673 kg/hr at 335°C temperature and clinker cooler with amount of 298, 667 kg/hr at 305°C temperature are exists. Those sources of waste heat have a lot of sensible heat and can be used for steam generation and this superheated steam which is produced in both boilers are used to rotate impulse steam turbine shows that the proposed technology can produce 7.35MW which yields considerable impact on the turnover. The methodology of this WHRPG cycle system using an approximate cement industries data will be presented in the future work.