Design and analysis of waste heat recovery heat exchanger from external kiln shell in cement plant

The rotary kiln's surface loses heat to the environment through radiation and convective modes, releasing usable thermal energy. This study focuses on examining and analyzing a cement plant's waste heat recovery heat exchanger from the external kiln shell. To attain the goal of the study, the modeling methodology relies on the fundamental equations of heat transfer and is enhanced by a Computational Fluid Dynamics analysis conducted with ANSYS Fluent. The finding shows that the maximum temperature of the kiln shell is 605.6 K in section 3 and the minimum is 520.7 K in section 8. The water's inlet temperature to the heat exchanger modelled on the kiln shell was raised from 298 K to 352.52 K for the cooler side with a mass flow rate of 0.5568 kg/s and from 298 K to 352.57 K for the preheater side with a mass flow rate of 0.4716 kg/s. A thermal energy audit for the rotary kiln shell shows that the total heat waste from the kiln shell to the environment in convective loss was 14.2367 kcal/kg.cl and radiation loss was 27.2874 kcal/kg.cl. Upon comparing the convective and radiation losses from the kiln shell, it was discovered that the waste heat was responsible for 34.3 % of the convective losses and 65.7 % of the radiation losses from the total waste heat released into the environment from the kiln shell. Finally, conducting the test for waste heat recovery and an inclusive, effective working fluid for many heat media were recommended.