Introduction of an efficient small-scale freshwater-power generation cycle (SOFC–GT–MED), simulation, parametric study and economic assessment

Abstract

One of the most favorable thermal desalination methods used widely today is Multiple Effects Distillation (MED). Thermal nature of MED process causes the integration of a desalination unit with a high temperature power cycle like gas turbine. The improvement in energy efficiency is obtained as a result of this combination. One of the high temperature power cycles which has cogeneration opportunities is Solid Oxide Fuel Cell–Gas Turbine (SOFC–GT). Integration of MED with SOFC–GT power cycle in 300–1000kW (size of SOFC) is considered in this article. The exhausted heat of SOFC–GT power cycle is used in Heat Recovery Steam Generator (HRSG) to produce a required motive steam for the desalination unit. Simulation, parametric studies and an economic analysis of the small scale MED unit in combination with SOFC–GT power cycle are carried out to investigate the system performance. Economic analyses are applied based on the Annualized Cost of System method. Results show that the combination of MED with the SOFC–GT power cycle makes the system more economic. It shows that in greater gas prices (more than 0.07 US$ per normal cubic meter), the increment in the number of effect has a remarkable influence to decrease the period of return.