Second generation Biofuels Beyond Oxygenates Workshop session on Biofuel sources and supply May 2, 2008, Brookhaven National Laboratory.

Second generation Biofuels

Beyond Oxygenates

Workshop session on Biofuel sources and supplyMay 2, 2008, Brookhaven National Laboratory

The First Generation of Biofuels

• Alcohols: process intensive of fermentation of sugars or simple molecules into mainly ethanol

• Biodiesel: esterification or transesterification of fatty acids contained in fats or oils

The two major first generation biofuels use specific feedstock, commodities competing with food for land.

Second Generation Biofuels: Basic Requirements

• Any biomass based fuel responding to engine and storage requirements

• Transparent use: minimize the boutique fuel impact on distribution

• High EROEI

• Environmentally friendly: recycling atmospheric carbon

Issues with First Generation Biofuels

• No transparency: Must be kept separated before blending. This translates into required investments of storage and pumping equipment.

• No transparency: Require engine modifications, even minor ones (e.g. flex fuels for ethanol)

• Differences in energy content: Oxygenates (ethanol or biodiesel) hard to get approval from OEM

Conversion of biomass to bio-energy

Environment and EROEI: The Carbon Cycle

CO2 Plant Material

Ethanol C Coal Veg. Oil

Hydro-carbons

CH4

MJ/Kg 20.1 26.7 30.4 39 44 49.8

Combustion of carbon based products

Any upgrade of biomass to a higher energy product will be by spending energyConversion

of solar energy to biomass

Higher Energy = Higher Reduced State

Savior Lipids • Nature, as it usually does, already finds the most

efficient way of storing energy: in Lipids. Plant first produce carbohydrates rich in oxygen, and then converts them in carbon-rich triglycerides, the most compact form of biological energy

• It would make more sense to start with the highest energy content biomass.

Biomass: Energy Crops Yields

• Ethanol feedstock crops and Oilseed are comparable (approx. 55,000 MJ/ha)

• Oil-rich algae potential for much higher yields (50 x higher?)

What are second generation biofuels?

Hydrocarbons fuels from two major paths:• Fischer-Tropsch (FT) applicable to any biomass =

Biomass-to-Liquids (BTL)• Hydrotreatment of fatty acids (HTFA) (animal or

vegetable oils and fat hydrolisates)

Carbon does not remember if coming from petroleum or biomass

Example: Jet Fuels from Biomass

• Both FT and HTFA produce aliphatic hydrocarbons

• Both result in clean burning fuels• To meet Jet fuel ASTM D1655 for energy

density and cold flow properties, FT and HTFA have to be hydrocracked, isomerized and reformed

• Minimum aromatics set to 8% (seal issue)

Hydrotreatment of oil-rich biomass (1)

The fatty acids are hydrolyzed and de-carboxilated

Hydrotreatment of oil-rich biomass (2)

Jet fuel hydrocarbons (Chevron Aviation)

The Challenge

1 ha Oil Palm produces 5 metric tonnes crude oil

palm1 metric tonne = 38.2 Gj

1 ha Oil Palm could produce 5 * 38.2 * 0.60 = 115 Gj of Jet fuel with a 60%

yield (DARPA)

To Produce one day worth of jet fuel (28.9

Petajoules), we would need to dedicate 251 103

ha of Oil Palm

Thank you!