Technical assessment of LNG based polygeneration systems for non-interconnected island cases using SOFC

Liquefied Natural Gas (LNG) is one of the most promising fuels with high calorific value and low specific GHG emissions that offers several advantages as an energy carrier for power generation. In this paper, a novel polygeneration concept based on LNG fired plant for power, cooling and drinking water production in island systems is presented. Two Solid Oxide Fuel Cell based energy systems (one simple SOFC and another hybrid concept of SOFC combined with GT) are modelled in Aspen Plus and compared with two conventional combustion based technologies (internal combustion engine and Gas Turbine Combined Cycle) in terms of overall efficiency. Furthermore, a Low Temperature Multi-Effect Distillation (LT-MED) plant was modelled and coupled with the energy systems to evaluate the waste heat recovery potential for desalinated water production. Moreover, three concepts for cold recovery from the LNG regasification plant were presented and modelled. Process simulations results revealed that the hybrid SOFC-GT plant is the best solution in terms of energy efficiency and the heat recovery of the exhaust gas in a LT-MED unit is a promising option for drinking water production with almost no energy cost. Last, from exergetic point of view, the cryogenic energy storage (CES) via the production of liquid air was evaluated as the best option for waste cold utilization during LNG regasification.