Evaluating Algae as an Alternative Fuel for Chemical Looping Combustion

Abstract

Chemical Looping Combustion (CLC) and Chemical Looping with Oxygen Uncoupling (CLOU) are low-pollution energy generation techniques conventionally utilizing natural gas or synthetic gas as fuel. Using a redox reaction of metal oxides in dual fluidised beds, CO2 can be captured and prevented from entering the atmosphere at efficiencies up to 80% [4,8]. Algae is a sustainable source of biofuel with the additional benefit of carbon capture through photosynthesis [7]. This Meta-Study attempts to determine the viability of algae as CLC/CLOU reactor fuel for long term sustainable energy generation by identifying trends in different fuels and reactants to see if algae fuel can produce an acceptable output and identify areas of weakness. Energy balance calculations were performed as well as thermal energy output, processing energy and enthalpy values. Graciliara sp. and Chlorella Vulgaris made the most effective fuels for CLC and CLOU respectively due to the low amount of algae required to produce fuel. For CLC, 3.57kg Graciliara sp. produced 1kg fuel. For CLOU, 1.7kg Chlorella Vulgaris produced 1kg fuel. CLOU was the most mass efficient with an energy/mass efficiency ratio of 11600kJ/kg compared to CLC’s 15.7kJ/kg. The energy balance ratio analysis of the production of algal fuel also identified Chlorella Vulgaris as the best fuel, with an EBR of -0.4 in CLOU. In terms of evaluating output, CLOU's energy/mass efficiency ratio surpassed a modern coal plant [45], whose value was 2840 kJ/kg. The defining factor was the enthalpy of reaction.