Need artificial lighting or concentrated solar light

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Need artificial lighting or concentrated solar light Small diameter to maximize light exposure Minimize wall fouling (to let light in) Need gas exchange to: eliminate O 2 supply CO 2 5 kg/m 2 /yr (dry) Capital cost: $100 per m 2 230
Feedstocks for Green Fuels and Chemicals Algae Under ideal conditions, high conversion of sunlight: 3% for algae 1-2 % for plants like corn or sugarcane Capture of carbon dioxide: Algae consume CO 2 Could be associated with fossil fuel power plants Algae in open pounds: 10 m 2 can capture CO 2 associated with 1kW of electrical power 231
Feedstocks for Green Fuels and Chemicals Algae Conversion to fuels: Pyrolysis of whole biomass: Produces low quality fuel Transesterification of lipids to biodiesel Deoxygenation of lipids to green diesel or jet fuel 232
Feedstocks for Green Fuels and Chemicals Algae New approach: Solazyme A limitation in regular algae production is the need for light: Sensitive to fouling Need for large areas to reduce concentration of algae that shade light from each other Instead of using energy directly from the sun, use energy from sugar Compact facilities 233
Feedstocks for Green Fuels and Chemicals Algae Very expensive to produce: Wheat straw: 0.04 $/kg Wood: 0.06 $/kg Macro-algae in ocean: 0.2 $/kg Micro-algae in open ponds: 3 $/kg Micro-algae in photobioreactors > 30 $/kg 234 Solazyme: Refocused away from fuels to high value food and cosmetics applications
Feedstocks for Green Fuels and Chemicals Algae Concerns: Fertilizer Algae need lots of nitrogen and phosphorus fertilizers Average elemental composition of dry algae: CH 1.7 O 0.4 N 0.15 P 0.0094 Fossil fuel is used to produce fertilizers (2 kg of CO 2 / kg of N) Agriculture reduces fertilizer use through crop rotation (e.g. soybeans before corn to get nitrogen fixation): not for algae Using wastewater laden with N would be ideal, but problems if wastewaters contain toxic materials (e.g. heavy metals): May inhibit algae growth May contaminate biofuels How to extract oil economically: Centrifuges to separate algae from water Drying: costly in energy Cold press followed by hexane extraction (toxic) or centrifugation Genetically-engineered algae escaping: more dead zones? 235
Outline What are Green Fuels and Chemicals? Why do we need Green Fuels and Chemicals? Feedstocks for Green Fuels and Chemicals The biorefinery concept 236
The biorefinery concept Strategies for petroleum substitution Learn from oil refining Various types of biorefineries Main product lines 237
The biorefinery concept Strategies for petroleum substitution 238 Produce biocrude that can be processed in petroleum refineries: e.g.: Envergent (Ensyn + UOP) O, N ? Produce chemical intermediates: e.g. succinic acid Develop new chemical industry based on oxygenates (BioAmber) (HTAS) Convert sugar to paraxylene (and then PET) (Origin Materials) Focus on end products: e.g. Coke plantbottle (PET) e.g. Origin Materials (Nestle, Danone)
The biorefinery concept Learn from oil refining 239 Non- Fuels products: < 10% of output about 50% of profits

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