(67c) Biomass Gasification: Steam Reforming of Tars Using Nickel Supported Montmorillonite
Biomass is considered as a potential feedstock for sustainable energy production that can be converted to chemicals, fuels, electricity etc., either by thermochemical or biological processes. Gasification is one of the thermochemical methods of converting biomass to synthetic gas (CO and H2), which could potentially be used to produce different chemicals such as acetic acid and ethanol via chemical or biological processes and/or generate electricity by using engines, turbines, fuel cells etc. However, the synthetic gas produced may contain different organic (Tars) and inorganic impurities, which have the potential to damage the process equipment used in different conversion processes. Hence, the synthetic gas has to be cleaned to remove these impurities, and the extent to which the gas has to be cleaned is dictated by the end use application.
Laboratory scale tests have been performed to evaluate catalytic tar removal. Nickel supported clays have been the focus of this investigation, since clay is relatively cheap and abundantly available. Nickel impregnated clay catalyst was prepared by wet impregnation technique and catalyst characterization was performed using XRD, BET, FTIR, SEM, and ICP. This catalyst has been tested on a laboratory scale flow reactor using naphthalene as a model compound to evaluate the removal efficiencies. Tests have shown that naphthalene removal efficiencies of greater than 95% were achieved with 7.5% Nickel Montmorillonite catalyst under the conditions tested (S/C - 5, GHSV- 9450 h-1, Napthalene Feed - 10.5 g/m3, Temperature - 750oC, Particle Size - 20-40 mesh, Test Duration - 100 Hours). Tests were also carried out to evaluate the effect of S/C ratio, gas hourly space velocity, varying nickel content, naphthalene feed, and temperature; the results of which will be discussed.