As shown in the article entitled Cornerstone Technology: Thermal Conversion Process (TCP) (2006), thermal conversion process was developed by a team of scientists over a 15-year period, utilizing modern engineering to apply basic science principles that have been understood for over two centuries. Thermal conversion process is a continuous flow-through process in a controlled environment using water, temperature, pressure and time, with no critical parameters. Thermal conversion process breaks down organic polymers into their smallest units, and reforms them into new combinations to produce clean fuels. After reprocessing, three separate product streams are produced from the feed stocks:

 

      1. Clean fuel gas

      2. Light organic liquid (oil)

      3. Solid product (carbon or minerals)

 

      Thermal conversion process is approximately 85% energy efficient (Julie Gross Gelfand, 2006), it has very low Btu requirements, due to short residence times of the materials in the process and to holding of water under pressure. Thermal conversion process uses steam naturally generated by feedstock, thereby recapturing the expended energy. Furthermore, it generates its own energy. The few main advantage of this technology is that it does not produce uncontrollable emissions and it uses recycled water throughout the process, and it does not produce secondary hazardous waste stream.

 

      Another type of biomass technology, chemical conversion, as stated in Wikipedia, it could be used to produce fuel that is more conveniently used, transported or stored, or to exploit some property of the process itself. Chemical conversion is a chemical manufacturing process in which chemical transformation takes place, that is, the product differs chemically from the starting materials. (Parker, S. (2006). McGraw-Hill dictionary of scientific and technical terms (5th ed.). New York: McGraw-Hill.) Most chemical manufacturing processes consist of a sequence of steps, each of which involves making some sort of change in either chemical makeup, concentration, phase state, energy level, or a combination of these, in the materials passing through the particular step.

 

            Wikipedia said that in chemical conversion, in most cases, the first step involves gasification, which step generally is the most expensive and involves the greatest technical risk. Biomass is more difficult to feed into a pressure vessel than coal or any liquid. Therefore, biomass gasification is frequently done at atmospheric pressure and causes combustion of biomass to produce a combustible gas consisting of carbon monoxide, hydrogen, and traces of methane. This gas mixture, called a producer gas, can provide fuel for various vital processes, such as internal combustion engines, as well as substitute for furnace oil in direct heat applications. Because any biomass material can undergo gasification, this process is far more attractive than ethanol or biomass production, where only particular biomass materials can be used to produce fuel. In addition, biomass gasification is a desirable process due to the ease at which it can convert solid waste (such as wastes available on a farm) into producer gas, which is a very usable fuel. 

 

      Nowadays many companies have started to involve and practice this technology as to sustain energy demand, for example, RWE Power, one of the leading energy production and generation companies in Germany, have successfully developed the process of converting CO2 into synthetic gas. The advantages of this technology is that it is widely available and naturally distributed. Besides, it require very low cost input and helps to convert waste into energy, in other words it helped to deal with waste. However, this technology has its constraints as it causes pollution to the environment since harmful gas will emit during the process, furthermore it utilizes big land portion, which may cause deforestation if largely expanded.

 

      The last method in biomass technology is biochemical conversion. Biochemical conversion makes use of the enzymes of bacteria and other microorganisms to break down biomass. In most cases, microorganisms are used to perform the conversion process: anaerobic digestion, fermentation, and composting.

 

      Biochemical conversion uses biocatalysts, such as enzymes, in addition to heat and other chemicals, to convert the carbohydrate portion of the biomass (hemicellulose and cellulose) into an intermediate sugar stream. (Energy Efficiencies and Renewable Energy, July 2013). These sugars are intermediate building blocks that can then be fermented or chemically catalyzed into a range of advanced biofuels and value-added chemicals. The overall process can be broken into the following essential steps:

 

• Feedstock Supply: Feed stocks for biochemical processes are selected for optimum composition, quality, and size. Feedstock handling systems tailored to biochemical processing are essential to cost-effective, high-yield operations.

• Pretreatment: Biomass is heated (often combined with an acid or base) to break the tough, fibrous cell walls down and make the cellulose and hemicellulose easier to hydrolyze (see next step).

• Hydrolysis: Enzymes (or other catalysts) enable the sugars within cellulose and hemicellulose in the pretreated material to be separated and released over a period of several days.

• (a) Biological Conversion: Microorganisms are added, which then use the sugars to                     generate other molecules suitable for use as fuels or building-block chemicals.

     (b) Chemical Conversion: Alternatively, the sugars can be converted to fuels or an entire                suite of other useful products using chemical catalysis.

• Product Recovery: Products are separated from water, solvents, and any residual solids.

• Product Distribution: Fuels are transported to blending facilities, while other products and intermediates may be sent to traditional refineries or processing facilities for use in a diverse slate of consumer products.

• Heat & Power: The remaining solids are composed primarily of lignin, which can be burned for heat and power.

 

      Biochemical conversion has been widely used by the U.S Department of Energy as to ensure America’s security and prosperity by addressing its energy, environmental and nuclear challenges through transformative science and technology solutions. The advantage of this technology is that it can have an abundant supply and it can be domestically produced for energy independence, however, there might be a consequence that it may or may not have energy gain and some fuels required for the process are seasonal.