Study of Low Temperature Combustion Engine Combined With High Temperature Fuel Cell

Abstract

There are two major areas that demand most of the energy viz. electricity and transportation sectors. Currently, due to the use of fossil fuels, like coal in electricity production and crude oil in transportation, a large amount of pollution is produced containing harmful gases like CO2, CO, HC, SOx, NOx, PM etc. So, there is an urgent need to find some suitable alternative that could not only be able to fulfil the energy demand but also reduce pollution. Renewable sources like solar, wind etc. are being widely promoted to be used for energy production due to their non-polluting advantage but they have some disadvantages like low efficiency, large space requirement and their weather dependent nature. In such a situation, the solid oxide fuel cell (SOFC) can prove to be one of the viable solutions to meet this challenge. It has high efficiency, requires less space, and is weather independent. SOFC can be used for electricity production very effectively and is non-polluting. It produces high grade heat energy, and anode off gas (AOG) as the by-product, and this can be used in a hybrid system. On the other hand, reactivity-controlled compression ignition (RCCI) engine is the one which can be easily adopted for transportation and power production. It has an advantage of low engine emission, nearly zero NOx and PM, high thermal efficiency and fuel flexibility. Different types of alternate fuels can be used effectively on RCCI. In this work a SOFC-RCCI hybrid system has been studied, and it has been proposed that RCCI engine could be operated with AOG to produce additional energy with the help of the by-product of SOFC. This not only increase the overall efficiency of the system but also produces very less amount of pollution. In the present work, mathematical model of SOFC and RCCI has been prepared and simulation results have been obtained. The experiments have been performed on the RCCI engine with AOG as fuel. The results show reduction in NO and smoke opacity up to 86.90% and 70.68% respectively. However, CO and HC emissions are increased as compared to conventional diesel combustion (CDC) due to the presence of CO and CO2 in AOG. The results show high indicated thermal efficiency of more than 50%, and nearly the same performance as CDC. Although the HC and CO emissions are observed to be on higher side, they can be easily reduced by adopting suitable measures such as catalytic converter. newline