Fuels cellulose

Rayon is unique among the mass produced man-made fibers because it is the only one to use a natural polymer (cellulose) directly. Polyesters, nylons, polyolefins, and acryflcs all come indirectly from vegetation they come from the polymerization of monomers obtained from reserves of fossil fuels, which in turn were formed by the incomplete biodegradation of vegetation that grew millions of years ago. The extraction of these nonrenewable reserves and the resulting return to the atmosphere of the carbon dioxide from which they were made is one of the most important environmental issues of current times. CeUulosic fibers therefore have much to recommend them provided that the processes used to make them have minimal environmental impact. 

Most of the commercial tree plantations that produce wood for captive use as a raw material in manufacturing operations use a portion as fuel. Examples of short-rotation plantations are Hsted in Table 38 (127). Paper companies in the southeastern United States are reported to have short-rotation plantings also, eg, Weyerhaeuser, James River Corp., Buckeye Cellulose, and Lykes Brothers, but the intensity of maintenance is not known (127). 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

More recently, interest has developed in the use of enzymes to catalyze the hydrolysis of cellulose to glucose (25—27). Domestic or forest product wastes can be used to produce the fermentation substrate. Whereas there has been much research on alcohol fermentation, whether from cereal grains, molasses, or wood hydrolysis, the commercial practice of this technology is primarily for the industrial alcohol and beverage alcohol industries. About 100 plants have been built for fuel ethanol from com, but only a few continue to operate (28). 

Supercritical fluid solvents have been tested for reactive extractions of liquid and gaseous fuels from heavy oils, coal, oil shale, and biomass. In some cases the solvent participates in the reactions, as in the hydrolysis of coal and heavy oils with water. Related applications include conversion of cellulose to glucose in water, dehgnincation of wood with ammonia, and liquefaction of lignin in water. 

In principle biomass is a useful fuel for fuel cells many of the technologies discussed above for using biomass as a fuel produce either methane or hydrogen directly and as highlighted below synthesis gas production from biomass for conversion to methanol is an attractive option. Cellulose-based material may be converted to a mixture of hydrogen (70% hydrogen content recovered), CO2 and methane by high-temperature treatment with a nickel catalyst. 

It is necessary to calibrate the 14C time scale for greater dating accuracy. However, the second-order variations are at least as important as the first-order constancy of atmospheric 14C. For example, they provide a record of prehistoric solar variations, changes in the Earth s dipole moment and an insight into the fate of C02 from fossil fuel combustion. Improved techniques are needed that will enable the precise measurement of small cellulose samples from single tree rings. The tandem accelerator mass spectrometer (TAMS) may fill this need. 

Bullen, M. L. and Thomas, P. H., Compartment fires with non-cellulosic fuels, in 17th International Symposium on Combustion, The Combustion Institute, Pittsburgh, Pennsylvania, 1979, pp. 1139 18. 

Carbon dioxide supply, for the molten carbonate fuel cell, 72 220 Carbon dioxide ternary systems, phase behavior of, 24 4—5 Carbon diselenide, 22 75t Carbon disulfide, 4 822-842 23 567, 568, 621. See also CS2 in cellulose xanthation, 77 254 chemical reactions, 4 824—828 diffusion coefficient in air at 0° C, 7 70t economic aspects, 4 834-835 electrostatic properties of, 7 621t handling, shipment, and storage, 4 833-834... 

Phosphoric acid-based systems, for cellulosics, 11 488 Phosphoric acid esters, 24 159 Phosphoric acid fuel cells (PAFC), 13 858— 860 12 203-204, 216-219 19 626 effects of carbon monoxide and sulfur in, 12 219... 

As an example we present here some computation results for the plasma treatment of the hospital patients room waste with advantage of plastics, cellulose and non-organic metal and glass parts. To check the efficiency of gas fuel generation from this waste we have simulated the limited oxidation within temperature range 1000 - 2500 °C. We have assumed that in 1kg of dry waste are (by weight) 60% of plastics, 15% of silicon glass, and 10% of... 

---