And biomass

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). 

Significant differences in net photosynthetic assimilation of carbon dioxide are apparent between C, C, and CAM biomass species. One of the principal reasons for the generally lower yields of C biomass is its higher rate of photorespiration if the photorespiration rate could be reduced, the net yield of biomass would increase. Considerable research is in progress (ca 1992) to achieve this rate reduction by chemical and genetic methods, but as yet, only limited yield improvements have been made. Such an achievement with C biomass would be expected to be very beneficial for foodstuff production and biomass energy appHcations. 

Table 32. Biofuels Utilization and Production and Biomass-Fueled Electric Power Plant Capacities in the United States ...

J. L. Jones and S. B. Radding, eds.. Thermal Conversion of Solid Wastes and Biomass, ACS Symposium Series 130, American Chemical Society, Washington,... 

The MTG process was developed for synfuel production in response to the 1973 oil crisis and the steep rise in crude prices that followed. Because methanol can be made from any gasiftable carbonaceous source, including coal, natural gas, and biomass, the MTG process provided a new alternative to petroleum for Hquid fuels production. New Zealand, heavily dependent on foreign oil imports, utilizes the MTG process to convert vast offshore reserves of natural gas to gasoline (59). 

The dominant role of petroleum in the chemical industry worldwide is reflected in the landscapes of, for example, the Ruhr Valley in Germany and the U.S. Texas/Louisiana Gulf Coast, where petrochemical plants coimected by extensive and complex pipeline systems dot the countryside. Any movement to a different feedstock would require replacement not only of the chemical plants themselves, but of the expensive infrastmcture which has been built over the last half of the twentieth century. Moreover, because petroleum is a Hquid which can easily be pumped, change to any of the soHd potential feedstocks (like coal and biomass) would require drastic changes in feedstock handling systems. 

Fig. 7. Biofuels and biomass electricity production. Courtesy of the National Renewable Energy Laboratory.

Adsorption of Metal Ions and Ligands. The sohd—solution interface is of greatest importance in regulating the concentration of aquatic solutes and pollutants. Suspended inorganic and organic particles and biomass, sediments, soils, and minerals, eg, in aquifers and infiltration systems, act as adsorbents. The reactions occurring at interfaces can be described with the help of surface-chemical theories (surface complex formation) (25). The adsorption of polar substances, eg, metal cations, M, anions. A, and weak acids, HA, on hydrous oxide, clay, or organically coated surfaces may be described in terms of surface-coordination reactions ... 

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. 

Solid Wastes and Biomass Large and increasing quantities of solid wastes are a significant feature of affluent societies. In the United States in 1993 the rate was about 1.8 kg (4 lb) per capita per day or nearly 190 Tg (2.07 X 10 U.S. tons) per year, but the growth rate has slowed in recent years as recycling efforts have increased. Table 27-4 shows that the composition of miscellaneous refuse is surprisingly uniform, but size and moisture variations cause major difficulties in efficient, economical disposal. 

The antibiotie Tylosin was produeed in a CSTR using Streptomyees fradiae in a 5 liter laboratory fermenter. For different substrate flow-rates the eoneentrations of produet and biomass were measured [23]. 

The capital cost of an IGCC plant for biomass or coal IS in the range of 1,500 to 2,000 per installed kW. A comparable natural gas fire facility costs about 750 to 1,000. The economics of biomass electricity based on IGCC technology depend on the relative cost of natural gas and biomass fuels. Biomass must be lower m cost than gas to pay back the additional capital cost of gas production and cleaning. A 1999 estimate suggestes that the biomass would have to be 3 per million Btiis cheaper than natural gas for biomass to be economical. 

Robert Boyle, an Irish chemist noted for his pioneering experiments on the properties of gases, discovered methanol (CH3OH) in 1661. For many years methanol, known as wood alcohol, was produced by heating hardwoods such as maple, birch, and hickory to high temperatures m the absence of air. The most popular modern method of producing methanol, which IS also the least costly, is from natural gas (methane) by the direct combination of carbon monoxide gas and hydrogen in the presence of a catalyst. Methanol also can be produced more expensively from oil, coal, and biomass. 

Gas turbine and combined cycle (gas and light fuel oils) Thermal power plant (coal, lignite, wood and biomass)... 

The concentration profiles for substrate, product and biomass in a plug flow system are shown in Figure 3.4. 

Our next assumption is related to process yield yields of product and biomass are 20% and 50%, respectively (Tp/S = 0.2, = 0.5). Moles of penicillin G produced are based on... 

Cellulose in the wastewater stream is not generated but it is consumed and biomass produced by the microbial population as a substrate for energy. 

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