Waste Heat Recovery in Cement Manufacturing for Energy Efficiency in Benue State, North Central Nigeria

Cement manufacturing is among the most energy-intensive industrial sectors in Nigeria, and the recovery of waste heat from kiln exhaust gases for power generation represents a significant opportunity to reduce energy costs and emissions at cement plants operating in Benue State, North Central Nigeria. This study investigates waste heat recovery options at a major cement manufacturing facility in Gboko, Benue State, evaluating technical configurations, energy savings potential, and financial viability of installed waste heat recovery systems. Plant energy audits and process measurements quantified the thermal energy content of kiln exhaust streams, clinker cooler air, and pre-heater tower exit gases across four production lines. System simulations using AspenPlus modelling software were conducted to design a Rankine cycle waste heat recovery unit optimised for local feed temperature and cooling water conditions. Capital cost estimates and operational parameters from similar systems installed in Nigerian and West African cement plants were incorporated into a financial model. Results indicate that installation of a waste heat recovery system could generate 8.2 megawatts of electrical power, reducing purchased electricity costs by 34 percent and decreasing the facility's carbon emission intensity by 18 percent. Payback period is estimated at 4.8 years at current industrial electricity tariffs. The study recommends that waste heat recovery be incorporated as a mandatory energy efficiency standard in industrial licensing conditions under Nigeria's emerging industrial energy management framework. Keywords: waste heat recovery, cement manufacturing, energy efficiency, Benue State, industrial energy.