Feedstock fossil fuel-based

A general conclusion is that incentives to convert conventional fossil fuel based technology into biomass based technologies are large, but implementation will be slowed down for several reasons. Firstly, there is the availability of biomass itself. The preferred feedstock should not compete with food production. Processes to convert such biomass practically into secondary energy carriers are not yet commercially available. In the mean time, technologies converting food related biomass will be implemented. But this will only occur for a limited period in the near future. 

A bio-based polymer on the other hand is a man-made polymer where the starting materials or raw materials (bnt not the polymer itself) are derived from living organisms (generally plants). These renewable feedstocks are used to make polymers varieties that are identical in chemistry to conventional fossil fuel-based plastics. 

Alternative feedstocks for petrochemicals have been the subject of much research and study over the past several decades, but have not yet become economically attractive. Chemical producers are expected to continue to use fossil fuels for energy and feedstock needs for the next 75 years. The most promising sources which have received the most attention include coal, tar sands, oil shale, and biomass. Near-term advances ia coal-gasification technology offer the greatest potential to replace oil- and gas-based feedstocks ia selected appHcations (10) (see Feedstocks, coal chemicals). 

Most of the plastics and synthetic polymers that are used worldwide are produced from petrochemicals. Replacing petroleum-based feedstocks with materials derived from renewable resources is an attractive prospect for manufacturers of polymers and plastics, since the production of such polymers does not depend on the limited supply of fossil fuels [16]. Furthermore, synthetic materials are very persistent in the environment long after their intended use, and as a result their total volume in landfills is giving rise to serious waste management problems. In 1992,20% of the volume and 8% of the weight of landfills in the US were plastic materials, while the annual disposal of plastics both in the US and EC has risen to over 10 million tons [17]. Because of the biodegradability of PHAs, they would be mostly composted and as such would be very valuable in reducing the amount of plastic waste. 

The selected biocatalyst is any of the already described alternatives based on R. rhodochrous bacteria ATCC No. 53968. Its concentration or proportion to the fossil fuel feedstock was neither reported nor claimed only a slight comment is made on the proportion between the crude oil and the biocatalytic aqueous solution, which states that it will not exceed one half the total incubation volumes. In addition, an additional amount of water, enough for desalting, is simultaneously added with the biocatalytic solution. The process is carried out by feeding the crude oil and water into a CSTR reaction vessel and stirred until an emulsion is formed. The mixture is incubated under stirring at temperature and pressure conditions, for a period of time adequate for both to occur, desalting and desulfurization. 

Biomass can provide substitutes for fossil fuels as well as electricity and heat. Its resource base is varied. Arid land, wetlands, forest, and agricultural lands can provide a variety of plants and organic matter for biomass feedstock. 

To convert these feedstocks into useful chemicals, mainly fermentation, chemical modification or thermochemical methods were applied. However, these processes were later abandoned in favor of the more economic and efficient processes based on fossil resources, in particular oil. Easier transport and more stable chemical composition (biomass feedstocks are highly diverse, depending on the source) are two relevant additional factors in favor of fossil fuels. Therefore, although the concept of biorefinery is attractive, there are several barriers to economically feasible. 

As discussed in this book (Chapter 2, for example) a main difference between fossil fuels and biomass as feedstocks is that in the former case the functionalization of base chemicals obtained from the oil (ethylene, propylene, aromatics, etc.) occurs essentially by introduction of heteroatoms, while in the case of biomass-derived based chemicals (glycerol, for example) it is necessary to eliminate heteroatoms (oxygen, in particular). Consequently, the catalysts required to develop a petrochemistry based on bio-derived raw materials need to be discovered and cannot simply be translated from existing ones, even if the knowledge accumulated over many years will make this discovery process much faster than that involved in developing the petrochemical catalytic routes. 

Only about 5% of the fossil fuels consumed today are used as feedstocks for the production of synthetic carbon-based products. This includes the products of the chemical and drug industries with a major portion acting as the feedstocks for plastics, elastomers, coatings, fibers, etc. 

In summary, monomer synthesis from basic, readily available inexpensive feedstocks based on fossil fuels is both an art and a science developed over the last half century or so. 

The greenhouse-gas-neutral claim is the result of the combination of renewable-resource-based feedstock, along with the purchase of renewable energy certificates (RECs) backed by lifecycle assessment data. These RECs will serve as an offset to cover all of the emissions from the energy used for the production of NatureWorks PLA. The company will purchase certificates for projected 2006 production at its 140,000 tonne capacity manufacturing plant and 182,000 tonne capacity lactic acid plant in Blair, Neb., USA, as well as at its corporate offices in Minnetonka, Minn., USA. The purchase of renewable energy will allow NatureWorks to decrease its fossil fuel footprint by 68%. 

The sky-rocketing crude oil prices in recent years and the continuous exploitation of fossil fuels demand that we make serious efforts toward sustainable biofuel and bioenergy production. Renewable energy derived from plant-based feedstocks, organic residues, and biowastes is expected to reduce our dependency on fossil fuels, reduce greenhouse gas emissions, and enhance the rural economy (Schmer et al., 2008). In the United States, liquid biofuels such as ethanol and biodiesel are primarily derived... 

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