Output heat from the rotary kiln by combustion products (hot gas) and the dissipative heat of clinker coolers (hot air) are the most critical heat losses of the cement manufacturing process. Energy waste in cement production and the lack of a system to recover this waste heat have always been problems. This study investigates comprehensive research for designing, modeling, energy, and exergy analyses of waste heat recovery systems at an actual cement plant for hydrogen production The Quixer´e cement factory, with a line of 3500 ton/day production rates, located in Quixer´e, a province in North Brazil, serves as our primary research site. The method of conducting this research is as follows: after identifying the points susceptible to waste heat recovery, a thermodynamic simulation of the proposed cycle has been performed in the EES. Then, by examining the types of cycles used in recovery systems, an innovative system was proposed, and the results related to the modeling and optimization of the system were presented. The study of a DS ORC used in the cement plants in terms of thermodynamics and using a PEM electrolyzer to produce hydrogen using the waste heat of the cement plants are the novelty of the present research, promising to bring new insights to the field. The optimization scenario based on CO2 emission reduction, exergy destruction rate, and hydrogen production as objective functions are defined. Results show that 8040 kW of total exergy destruction rate belong to the electrolyzer heat recovery system (EHRS), proton exchange membrane (PEM) electrolyzer, and air heat recovery system (AHRS), which is about 72 % of the total exergy destruction rate of the system. The simulation results of the integrated system show that the produced hydrogen is about 19.43 kg/h. The results reveal that the CO2 emission reduction monotonically increases with the increment of mass flow rates and working pressures. Three-objective optimization based on CO2 emission reduction, exergy destruction rate and hydrogen production rate show that using the ideal point approach, the optimum value of objectives are E˙ xd,tot = 11501.09kW, CO2 mitigation= 835.02 kg/h, and m˙ H2 = 27.22kg/h.
