A "What & Who" of technology development
Future biofuels from algae and bacteria
When thinking about renewable motor fuels maybe the first things that come to mind is ethanol from corn or sugarcane and biodiesel from rapeseed, soybeans or palm oil. These are the dominant renewable fuels today but there are new sources, conversion processes and fuels’ molecules round the corner.
Cellulosic ethanol is the same well-known molecule but lignocellulosic raw materials are used instead of starch and sugar so the conversion process has to be different. Researchers and companies in this area are attempting to develop an efficient method for cellulose hydrolysis – the conversion of cellulose to fermentable sugars.
Converting C5 sugars to ethanol
The second major issue in this field is the conversion of not only six carbon atom sugars, C6, to ethanol but also the C5 sugars, to get an acceptable yield from the raw material. Some leading companies in this “conventional” cellulosic biomass domain are Verenium, Iogen, Abengoa and Inbicon, just to mention a few. Interesting to note is that two Danish companies, Novozymes and Danisco through their Genencor division have very strong positions in the enzyme technology, crucial for this route.
OriginOil biochemist Heather Heath adds incubant to the algal biomass process. Photo: OriginOil
Biological conversion without separate hydrolysis
Some companies have come up with alternative routes for the conversion of cellulose and sugars. Zeachem is developing a process where all the cellulose and hemicellulose is converted biologically to acetic acid which is then converted over ethyl acetate and hydrogenation to ethanol. The hydrogen is to be obtained from gasification of the lignin that remains after the biological conversion and then CO-shifting the gas. In this way Zeachem hopes to reach yields not obtainable through more conventional cellulosic alcohol processes.
A similar process is the Texas A&M University MixAlco process which from biomass over carboxylic acids produces mixed alcohols with a high percentage ethanol. Mascoma is another high profile company in the cellulosic ethanol arena researching the possibility to convert cellulose directly to ethanol with genetically modified bacteria. Another entry with this single-step approach is Qteros.
Thermochemical conversion through gasification
Ethanol or mixed alcohols can also be produced over the thermochemical route through gasification and synthesis. Classic synthesis processes include the Dow mixed alcohols process and the Lurgi Octamix process. Currently Range Fuels is attempting to use biomass as the gasification feedstock in a mixed alcohols process tweaked to produce a high percentage ethanol. Coskata and INEOS Bio are companies developing biological conversion systems for syngas to ethanol.
The thermochemical route also allows the production of other biofuels including hydrocarbons over the Fischer-Tropsch route, methanol and dimethyl ether (DME). Constellations developing gasification based process systems for these fuels include Choren, Andritz-Carbona/UPM/GTI, StoraEnso/Foster-Wheeler/Neste, TRI/Syntroleum and of course Chemrec. Syngas can also be converted to gasoline components through the EXXONMobil MTG or Haldor-Topsøe TIGAS processes.
Fuels other than ethanol from sugars
A few companies are looking at producing fuels other than ethanol from sugars. Virent is researching the production of gasoline component hydrocarbons from sugars through catalytic hydrogenation. Avantium is instead converting sugars to furans in a thermocatalytic process. Furans are claimed to be an excellent diesel fuel. LS9 is using sugars as the raw material, feeding it to microorganisms producing fatty acid intermediates that can be converted into hydrocarbons suitable as gasoline, diesel fuel or jet fuel components.
Production of fuels from flash pyrolysis of biomass is also attracting a lot of attention today. Early players in this field include Dynamotive, Ensyn and Lurgi. Among recent entries the pulp-, paper- and minerals-technology giant Metso can be found. In this field a hot topic for research is the direct upgrading of fractions of the pyrolysis oil through hydrogenation to gasoline or diesel components. Ensyn has together with UOP recently formed a new venture, Envergent Technologies, dedicated to this task.
Algaes producing fat
The new really hot area in biofuels is algal biomass. It is still a technology in its infancy but with a very high theoretical potential. In these systems the high photosynthesis capacity of algae is used to produce biofuel raw materials. The most common approach is cultivating algae capable of producing intra-cellular fat as the primary product. The fat can then be separated from the rest of the algal biomass to become a biodiesel raw material. A multitude of companies and research organizations are active in this area, examples are PetroAlgae and Origin Oil. Key issues to resolve in this field are the resilience of the biological system in industrial scale cultivation and of course the costs for infrastructure, cultivation and upgrading.
These are only a handful of examples of development directions. Many other interesting activities are going on along the whole value chain of biofuels – from the genetics and cultivation methods of the primary biomass production, through the biomass conversion and on to the use of advanced biofuels in automotive power trains. We will in future issues give additional glimpses of these exciting technologies.