Algae to Fuel

Basics

• This page aims to cover the various ways Algae can be converted into Usable Fuel
• Various technologies/levels of complexity will be covered
  • Some Technologies may not Scale well

Higher Complexity

Transesterification Biodiesel

• This is one of the most known/commercially available processes
• Main issue is it needs Algae Concentration/Drying, then Plant Oil extraction
• Also the Transesterification process uses Methanol so you need fuel to make fuel etc
  • That and Solvent Extraction of the Oil is used in some processes
• A Crude system using
  • An Open Source Expeller Press
  • Large Raceway Pond Algae Farming and a Cheesecloth Bag/Screen Printing + Airlift Pump Semi-Continuous Algae Harvesting System + Basic Sun Drying
• Advantage is short of Gell Point / Cloud Point issues in Cold Weather, and MAYBE some Fuel Lubricity issues, Bio-Diesel once seperated+washed etc can be used as is, in Off The Shelf Engines etc

Hydrothermal Liquefaction

• aka HTL
• Hydrothermal Liquefaction is nice in that no Algae pre-processing is needed, short of SLIGHT concentration in a centrifuge etc
• Produces Bio-Crude
  • Can be used as is in a Crude Oil Engine or External Combination Engine using a Babington Burner etc
  • Also could be used as is for Process Heating (re Home Heating Oil / Fuel Oil etc)
  • Also could potentially be used in more conventional engines with Filtration and Dilution with a solvent (re Dillbit etc
• Main issues are the complexities of the process/reactor, and it producing a Bio-Crude, rather than something more easily purified+used
• Scales Up Well, and is an ESPECIALLY good candidate for Fossil Fuel Phaseout / Fossil Oil Phaseout via drop on biocrude

Lower Complexity

Anaerobic Digestion

• Given ose already has Anaerobic Digestion equipment, re Biodigester this is easy to do
• Also if used directly (as Biogas ) or if scrubbed/upgraded (as Biomethane or RNG ) is is a pretty high quality and easily usable fuel
• Main downside is storage
  • CNG requires heavy upgrading, as well as High Pressure Compressors
    • Not IMPOSSIBLE, just not something you can put in a Jerry Can or bucket
  • ANG ( Adsorbed Natural Gas ) may be doable, but is at a lower Technology Readiness Level
• As per ~this paper~ , Algae can be used to scrub the biogas iteself, if properly integrated
  • Although in high end setups having sensors + backup chemical or mechanical scrubbing may be worthwhile to maintain quality

To-Do’s

• Yield per Liter of Algae
  • Also impact of Algae Slurry Density, Algae Age/Growing Conditions etc
• Role of Digester Microbes/Enzymes
  • While not as critical as Fermentation , making sure the microbes can fully digest the algae (if using whole algae slurry, not extracted Algae Oil etc) may be worth looking into
• Pre-Processing
  • Is some sort of Sterilization / Pasteurization advisable to prevent overwhelming the Microbiome of the Digester?
    • This may also aid in breaking down cell walls (Akin to Lysomy Broth ) and/or breaking down Starches into Sugars and/or Sugars into Simpler Sugars etc (Akin to Invert Sugar )
• Residence Time Required for Full Digestion vs Residence Time in the IBC Tote Biodigester

Fermentation

• Using microbes to make Ethanol , Methanol , or Butanol (And a whole wealth of other potential products, re ABE Fermentation , Formic Acid , Precision Fermentation etc)
• May be difficult with standard algae and standard Yeast / E. Coli
  • Enzymes/Optimization for Breaking Down Oils and/or Cell Walls/Non-Corn Starch type feedstocks will likely be required
    • Akin to Cellulosic Ethanol
• Main advantage of this is as per Beer and Distilled Drinks this is a LOW tech process once set up
  • Although as with anything the process CAN be optimized with Sensors/Heat Exchangers/Stainless Steel Vats etc, but a Ceramic Jar COULD do the job too is the point
• Also while not AS similar to the Fossil Equivalent as Bio-Diesel is (Mainly for Ethanol, due to it being Hydroscopic leading to more Rust + Potential Phase Separation issues, as well as some potential for Material Compatibility Issues with older/cheaper Fuel Systems/Gaskets etc), Alcohol Fuels are readily usable (Even in a Soda Can Alcohol Stove etc), and in some regards such as Octane Rating or Long Term Storage etc are superior to Fossil Gasoline

As a Solid Fuel/Feedstock

Direct Burning

• While potentially not as efficient as some other methods, nor as High Quality of a fuel as other options, this may work
• Any system utilizing Expeller Pressing / Solvent Extraction of Plant Oils etc will also yield a Filter Cake which may be a fuel in of itself (If not fed into Source Separated Organics routes, or used as Animal Feed etc)

To-Do’s

• Calorific Value of:
  • Algae Slurry (of varying concentrations+impact of Algae Growth Media on Ash Content etc)
  • Dried Algae Powder
  • Algae Filter Cake
• Pelletizability of Algae
• Potential Co-Firing synergistic behaviors