Waste heat recovery in a chemical process and plant, particularly for the synthesis of ammonia

Abstract

A method for recovering waste heat in a process for the synthesis of a chemical product, particularly ammonia, where the product is used as the working fluid of a thermodynamic cycle; the waste heat is used to increase the enthalpy content of a highpressure liquid stream of said product (11), delivered by a synthesis section (10), Jhus obtaining a vapour or supercritical product stream (20), and energy is recovered by expanding said vapour or supercritical stream across at least one suitable expander (13); the method is particularly suited to recover the heat content of the syngas effluent, after low-temperature shift.