Hydroprocessing Microalgae Derived Hydrothermal Liquefaction Bio-Crude for Middle Distillate Fuels Production – A Review
Bio-crude, a biomass derived oil similar to petroleum crude in properties, can be produced from microalgae via hydrothermal liquefaction (HTL) and upgraded to middle distillates fuels by hydroprocessing which is a very common refinery technology. This paper reviews available literature on HTL of microalgae and the subsequent upgrade of the bio-crude into middle distillate fuels via hydroprocessing. Experimental and process simulation results from different studies were used to explore the differences and similarities between the bio-crude and conventional crude; the methods and process conditions for hydroprocessing the bio-crude; the products obtainable, their compositions & properties; as well as the inputs required for modelling and simulation of the process. The review illustrates that the same fuels (of almost the same properties) can be produced from the bio-crude as from petroleum crude; the process conditions depend on the required product distribution (maximum diesel or kerosene/jet range fuels); and the process is characterized by much higher hydrogen consumption than hydro processing conventional crude.