Emission Characteristics of Gasohol and Diesohol

The term biofuel is referred to liquid, gas, and solid fuels predominantly produced from biomass. Biofuels include bioethanol, biomethanol, vegetable oils, biodiesel, biogas, bio-synthetic gas (bio-syngas), bio-oil, bio-char, Fischer-Tropsch liquids, and biohydrogen. Biomethanol can be produced from biomass using bio-syngas obtained from steam reforming process of biomass. Biomethanol is considerably easier to recover than the bioethanol from biomass. Ethanol forms an azeotrope with water so it is expensive to purify the ethanol during recovery. Methanol recycles easier because it does not form an azeotrope. Gasoline and ethanol mixtures are called gasohol. Diesohol is a mixture of diesel fuel and hydrated ethanol that is blended using a chemical emulsifier. Diesohol is used in compression ignition engines as an alternative diesel fuel. The reductions of carbon monoxide and carbon dioxide were 32 and 29% for CO emissions and 43 and 45% for CO2 emissions of E15 gasohol and diesohol, respectively. The reductions of unburned hydrocarbon were 27 and 24% for E15 blends and 74 and 69.8% for E60 blends of gasohol and diesohol, respectively.