evidence: In this circumstance, the sulfuric acid production is an exothermic process (Aroussy et al. 2016a), in which the heat is recovered from absorption process of sulfuric acid by heat recovery system (HRS), with negligible temperature losses and minimum space requirements. The heat recovered is used for district heating of cities, boiler feed water preheating or as heating media in connected processes or adjacent plants. Indeed, it provides the entire need for sulfuric acid and steam for the production of phosphoric acid, fertilizer and the electrical energy required to power the plant. In this work, the sulfuric acid is used to recover heat energy in power plant which is used in a hybrid system of RO–MED in order to desalinate the seawater. A thermodynamic steady-state study of this system is investigated to select the optimum cogeneration system.