The fuel property and application prospect of water-containing biofuel from Clostridium acetobutylicum fermentation products

Biobutanol, a promising green alternative fuel, fermented from Clostridium acetobutylicum, while its high-cost and limited yield constraining its development. ABE (acetone-butanol-ethanol) and IBE (isopropanol-butanol-ethanol) are mixed fermentation products from non-edible biomass raw materials, using them together with water as alternative fuels will reduce industrial production costs and save fossil fuels. Therefore, this study conducted a multifaceted experimental evaluation on ABE/IBE mixed fuels with different water content, demonstrating that it has good water holding capacity when mixed with traditional fossil fuels. Taking ABE (3: 6: 1) as an example, its water holding capacity after mixing with diesel at 10–90 % is 0.37–7.83 % at 20 °C. Meanwhile, the particle size of ABE/IBE mixed fuels is about 2–30 nm, exhibiting a microemulsion with thermodynamic stability. The anhydrous or water-containing mixed fuel with the ratio of ABE (IBE) of 10%–50 % meets the range of the density and kinematic viscosity of diesel engine fuel. The mixed fuel is non-corrosive to copper without water, and a water content of about 3 % or higher will increase the risk of engine corrosion at 20 °C. Despite the addition of biofuel and water, studies on energy combustion performance and pollutant emission performance have found that appropriate addition of biofuel and water can produce higher power output and lower pollutant emissions than traditional fossil fuels, with ABE20W0.5 being the optimal. This study demonstrates the great potential of ABE and IBE as biofuels to achieve carbon neutrality goals, providing novel research direction for green alternative fuels in the future.