Development of a Novel Adsorption Separation Process of Bio-based Butanol for the Alternative Energy Sources

Bio-based butanol has superior properties when compared to ethanol to be the gasohol and is gradually considered to be an important biofuel from the biomass fermentation. These properties include higher calorific value, low vapor pressure, low freezing point and miscibility with gasoline and diesel. DuPont (US) and BP (UK) announced their plans to produce bio-based butanol to be used as a new gasoline extender. Butanol can be produced by non-food products of fiber fermentation by Clostridium acetobutylicum or C. berijerinckii with acetone and ethanol as by-products. This acetone-butanol-ethanol (ABE) fermentation process used to be the main process for industrial production of butanol. The ABE solution concentration is around 20 g/L of which butanol is only 8-13 g. As expected, the energy cost for traditional distillation to recover butanol will be very high. The adsorption using silicalite (e.g. high Si/Al zeolites) is the most energy efficient method compared to pervaporation, gas stripping and liquid-liquid extraction. The results were observed that ZSM-5 zeolite has the highest selectivity for butanol adsorption. However, ZSM-5 still adsorbs minor ethanol and acetone. Therefore, the sorbent SAPO-34 was further used to adsorb ethanol and acetone. This novel multi-step adsorption process was applied to separate the bio-based butanol from the ABE solution and the purity of butanol can reach more than 99%. To reduce the fossil fuel crisis and the environmental impact, the promotion of the biofuels is considered gradually. In the latter part of nineteenth century, the first diesel engine was developed to run vegetable oils in Germany. Since the polymerization of unsaturated plant oil may cause the high viscosity of the oil, the use of plant oil in engine directly should overcome the contamination of filter and lubricant oil in the engine system. The proposed bio-based butanol made from the waste fiber fermentation and the property to be the biofuel compared to the fossil fuel is better, especially on the reducing of total carbon dioxide emission. The promotional and implementation projects of the plantation of Jatropha curcus for the alternative energy in tropical area of Indonesia will be introduced also. The Jatropha curcus seed oil can be made of biofuel and the fiber residue may become the feedstock for bio-based butanol.