(675b) Different Parameters Controlling the Biocrude Yield in Hydrothermal Liquefaction of Microalgae

Authors: 
Mallick, K., New Mexico State University
Cheng, F., New Mexico State University
Brewer, C. E., New Mexico State University
Nirmalakhandan, N., New Mexico State University
Research into alternate sources of fuel or renewable energy reveal many promising ideas for alternative energy sources. One of these possibilities is converting biomass to biofuel. Under high pressure and temperature, microalgae can be polymerized to biofuel. There are some thermo-chemical processes available to convert the biomass like pyrolysis and gasification, but these processes require dry feedstock. Thus these processes encounter large energy loss by vaporizing the moisture. Hydrothermal Liquefaction (HTL), a high temperature, high-pressure polymerization process, can convert wet biomass, including water to biocrude oil, biochar, and nutrient rich water. The biocrude obtained from HTL are environmentally friendly and can be directly used as fuel or can be upgraded to transport fuel. Many researchers are working on increasing the efficiency of HTL. In the present study an attempt is made to optimize the HTL reactor for maximizing the biocrude yield. Batch reactions are carried out to correlate the biocrude yield with different parameters like the reaction temperature (300°C - 350°C), reaction time (30 mins â?? 60 mins), initial solid concentration (5% - 20%) and also different species with different lipid contents. Experiments are also carried out to see the effect of different cultivating medium (wastewater and freshwater) on the crude yield after HTL. Experimental results show that different operating conditions can result in the biocrude yield to vary between 5% and 60%. These parameters are also related to the amount of heavier biocrude oil produced. This paper carefully examines and explains the relationships between the operating conditions and the biocrude yield to be able to optimize a HTL batch scale reactor for maximum crude yield.
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