Thermochemical biomass conversion involves processes at much higher temperatures and generally higher pressures than those found in biochemical conversion systems. Key intrinsic characteristics distinguishing thermochemical from biochemical biofuels are the flexibility in feedstocks that can be accommodated with thermochemical processing and the diversity of finished fuels that can be produced. Thermochemical production of biofuels begins … Read More

The fuel properties of second-generation ethanol or butanol are identical to those of the firstgeneration equivalents, but because the starting feedstock is lignocelluose, fundamentally different processing steps are involved in producing them. Second-generation biochemically-produced alcohol fuels are often referred to as “cellulosic ethanol” and “cellulosic biobutanol”. The basic steps for producing these include pre-treatment, saccharification, … Read More

Second-generation biofuels share the feature of being produced from lignocellulosic biomass, enabling the use of lower-cost, non-edible feedstocks, thereby limiting direct food vs. Fuel competition. Second-generation biofuels can be further classified in terms of the process used to convert the biomass to fuel: biochemical or thermochemical. Second-generation ethanol or butanol would be made via biochemical … Read More

The most well-known first-generation biofuel is ethanol made by fermenting sugar extracted from sugar cane or sugar beets, or sugar extracted from starch contained in maize kernels or other starch-laden crops. Similar processing, but with different fermentation organisms, can yield another alcohol, butanol. Commercialization efforts for butanol are ongoing, while ethanol is already a well-established … Read More

A variety of pyrolysis processes have been developed to convert municipal solid wastes and agricultural and wood residues to solid, liquid and gaseous fuels. The thermal process can be designed to maximize the desired end products since the quantity of char, bitumen-like liquid and gas produced varies as a function of the time and temperature … Read More

The pre-treatment of wastes requires a number of different processes such as crushing, drying and deodorizing. An innovative hydrothermal pre-treatment system called Resource Recycling System (RRS) had been developed that can perform these three pre-treatment functions in one step using high pressure saturated steam. This technology is characterized by low energy requirements for drying. Figure … Read More

The development of photosynthetic microbes that produce lipids or hydrocarbons also has great potential for biofuels production. While plant production of useable biomass is unlikely to exceed an overall solar conversion efficiency of 1-2 percent, algae can convert solar power at efficiencies in excess of 10 percent. A combination of anaerobic and aerobic microbial processes … Read More

First generation biofuels technologies comprise mainly of fuel ethanol from crops such as corn and sugarcane and biodiesel from crops such as rapeseed and soy. Second generation processes are those that produce energyefficient biofuels that do not compete with the food chain for feedstocks. Secondgeneration processes convert lignocellulosic materials, including agricultural and forest residues such … Read More

The first generation biofuels are those that are characterized by mature commercial markets and well understood technologies3. Some examples are sugarcane ethanol in Brazil, corn ethanol in the United States, oilseed rape biodiesel in Germany, and palm oil biodiesel in Malaysia. The development and use of first generation biofuels are encouraged by the desire to … Read More

The first and most important advantage of MHF is that it is generally cheaper than biodiesel and has the potential to be cheaper than diesel fuel. Two factors have significant impact on the price of biodiesel: first, the price of the raw material, which is plant oil; and second, the prices of the chemicals used … Read More