Energy conservation is of paramount importance in oil and gas industries. Sulfur recovery units (SRUs) in oil and gas industries are required to meet the stringent environmental emission regulations, and are often viewed as production costs. They are normally net energy exporters and a considerable portion of heat is recovered as high-pressure steam. However, SRUs processing lean acid gas streams require significant amounts of acid gas and air preheating before they enter the reaction furnace. Some portion of the generated high-pressure steam is used in preheating these streams. This reduces the overall net high-pressure steam generated from the SRU. Here, heat integration is used and an existing SRU facility is retrofitted such that there is an increase in net high-pressure steam production. Seven new heat-integrated SRU configurations are proposed, and key aspects such as net high-pressure steam production, investment costs, and payback period for each of the new retrofitted configurations are compared.