Configurations and Operation Methods of Diesel-Based Solid Oxide Fuel Cell System

Abstract

Solid oxide fuel cell(SOFC) is a recently developed technology which has attracted increasing attention for its high efficiency and low emission. While the production and delivery of hydrogen still have giant obstacles, diesel will be a good substitute for its high heating value and low cost. However, it has not been widely used as the fuel for SOFC and researches on diesel-based SOFC system still remains to be further explored. In this work, a diesel steam reforming(SR)-SOFC system is studied. We proposed a series of system configurations of diesel-based SOFC and fitted key system units based on measured data of reforming and stack experiments. Moreover, the best system operation condition intervals were presented to achieve the maximize system efficiency and heat balance. The results suggest that a system with anode off-gas recirculation and electrodes off-gas mixture has the highest efficiency because it has higher syngas heat value and lower off-gas temperature; by adding a water condenser between reformer and SOFC stack, the system efficiency can be improved for higher percentage of H2 in syngas although the condenser will take away a part of the heat. Under this system configuration and the best system operation condition interval , the system efficiency can reach 58.2%(the stack efficiency is 45.8%), improving approximately 10% comparing with the system without anode off-gas recirculation. This research reveals the efficiency variance between different system configurations and gives a better system configuration as well as preferred operation methods, which lays a theoretical foundation for the upcoming design of a 100kw class physical system.Keywords: solid oxide fuel cell, diesel reforming, system configurations, operation method