Second Generation Biofuels

Second-generation fuels are made from lignocellulosic biomass feedstock using advanced technical processes'

Second generation biofuels use biomass to liquid technology. The following second generation biofuels are under development:

• BioHydrogen
• Bio-DME
• Biomethanol
• DMF
• HTU diesel
• Fischer-Tropsch diesel
• Mixed Alcohols (i.e., mixture of mostly ethanol, propanol and butanol, with some pentanol, hexanol, heptanol and octanol)

Bio-DME, Fischer-Tropsch, BioHydrogen diesel, Biomethanol and Mixed Alcohols all use syngas for production. This syngas is produced by gasification of biomass. HTU (High Temperature Upgrading) diesel is produced from particularly wet biomass stocks using high temperature and pressure to produce an oil.

BioHydrogen is the same as hydrogen except it is produced from a biomass feedstock. This is done using gasification of the biomass and then reforming the methane produced. BioHydrogen can be used in fuel cells to produce electricity.

DMF. Recent advances in producing DMF from fructose and glucose using catalytic biomass-to-liquid process have increased its attractiveness.

Bio-DME is the same as DME but is produced from a bio-sources. Bio-DME can be produced from Biomethanol using catalytic dehydration or it can be produced from syngas using DME synthesis. DME can be used in the compression ignition engine.

Biomethanol is the same as methanol but it is produced from biomass. Biomethanol can be blended with petrol up to 10-20% without any infrastructure changes. 

HTU diesel is produced from wet biomass. It can be mixed with fossil diesel in any percentage without need for infrastructure. 

Fischer-Tropsch diesel (FT)diesel is produced using gas-to-liquids technology. FT diesel can be mixed with fossil diesel at any percentage without need for infrastructure change.

Mixed Alcohols are produced from syngas with catalysts similar to those used for methanol. Most R&D in this area is concentrated in producing mostly ethanol. However, some fuels are marketed as mixed alcohols (see Ecalene) ^{[8] [9]}. Mixed alcohols are superior to pure methanol or ethanol, in that the higher alcohols have higher energy content. Also, when blending, the higher alcohols increase compatibility of gasoline and ethanol, which increases water tolerance and decreases evaporative emissions. In addition, higher alcohols have also lower heat of vaporization than ethanol, which is important for cold starts. (For another method for producing mixed alcohols from biomass see bioconversion of biomass to mixed alcohol fuels)

Wood diesel A new biofuel was developed by the University of Georgia from wood chips. The oil is extracted and then added to unmodified diesel engines. Ether new plants are used or planted to replace the old plants. The charcoal byproduct is put back into the soil as a fertilizer. According to the director Tom Adams since carbon is put back into the soil, this biofuel can actually be carbon negative not just carbon neutral. Carbon negative decreases carbon dioxide in the air reversing the greenhouse effect not just reducing it.