Filtration effects on the alkali metal content of biocrude oil
- National Renewable Energy Lab., Golden, CO (United States)
The production of fuels and chemicals from biomass feedstocks is one of the areas of renewable energy research at the National Renewable Energy Laboratory (NREL). Fast pyrolysis is one of the thermochemical conversion methods being developed at NREL for recovering the stored energy in biomass. The physical properties of thermochemically derived biomass fuels are very important if these fuels are to be used for electrical power generation, in steam boilers, or diesel fuel. The alkali metal content of the biocrude is very critical if it is going to be used as a turbine fuel to avoid damaging or wearing turbine blades. To study the origin of alkali metals, calcium and other trace inorganic content of biocrude, switchgrass (Panicum virgatum L.) was pyrolyzed in a bench-scale fluidized bed reactor at 500{degrees}C. After pyrolysis, cold filtration and leaching tests were carried out on die biocrude derived from the switchgrass. Cold filtration and leaching test results showed that the char particles in the oil are the main cause of the high alkali metal contents. The inorganics are sequestered in the char particles and do not leach into the oil phase. These char particles are of submicron size and cannot be easily removed by cold filtration. Consequently, a small hot gas filtration unit was attached to the fluidized bed reactor to remove the char particles in situ. An analysis of die hot gas filtered pyrolysis oils for alkali metals and ash showed that alkali metal content can be reduced to less than 10 ppm compared to 250-300 ppm for a cyclone separated oil.
- OSTI ID:
- 214755
- Report Number(s):
- CONF-950801-; TRN: 96:000922-0227
- Resource Relation:
- Conference: 210. national meeting of the American Chemical Society (ACS), Chicago, IL (United States), 20-25 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of 210th ACS national meeting. Part 1 and 2; PB: 1866 p.
- Country of Publication:
- United States
- Language:
- English
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