Energies systems

It is often possible to use the energy system inherent in the process to drive the separation system for us by improved heat recovery and in so doing carry out the separation at little or no increase in operating costs. 

We have it on good authority (Ege, 1998) that the gauche minimum on the potential energy coordinate is about 0.9 kcal moI higher in energy than the anti conformation. This establishes a two-state energy system for the stable conformers, gauche and anti (Fig. 4-19). 

Alcohol Energy Systems Alcohol Elect One Test Report, Pub. 500—82—058, California Energy Commission, Sacramento, Calif., Aug. 1983. 

Distribution of Carbon. Estimation of the amount of biomass carbon on the earth s surface is a problem in global statistical analysis. Although reasonable projections have been made using the best available data, maps, surveys, and a host of assumptions, the vaHdity of the results is impossible to support with hard data because of the nature of the problem. Nevertheless, such analyses must be performed to assess the feasibiHty of biomass energy systems and the gross types of biomass available for energy appHcations. 

There are many grasses and related plants that can be considered for energy apphcations because they have the desirable characteristics needed for land-based biomass energy systems. 

Another factor is the potential economic benefit that may be realized due to possible future environmental regulations from utilizing both waste and virgin biomass as energy resources. Carbon taxes imposed on the use of fossil fuels in the United States to help reduce undesirable automobile and power plant emissions to the atmosphere would provide additional economic incentives to stimulate development of new biomass energy systems. Certain tax credits and subsidies are already available for commercial use of specific types of biomass energy systems (93). 

One method of analyzing net energetics of a biomass energy system is to let E E, and represent the energy content of the dry biomass feed, E ... 

Location of the system boundaries also is important in the net energy analysis of integrated biomass energy systems. Thus tractors may be used to plant and harvest biomass. The fuel requirements of the tractors are certainly part of E, but is the energy expended in manufacturing the tractors also part of E Some analysts beheve that a complete study should trace all materials of constmction and fossil fuels used back to their original locations in the ground. 

K. A. Saterson and M. W. Luppold, 3rd Annual Biomass Energy Systems Conference Proceedings, SERI/TP-33-285, U.S. Department of Energy, Golden, Colo., June 5-7, 1979, pp. 245-254. 

H. Oman, Energy Systems Engineering Handbook, Prentice-Hall Inc., Englewood Cliffs, N.J., 1986. 

Ideally, a process plant should be examined for its total energy consumption (see Energy management). Other plant energy systems are under consideration (18) and should eventually be included in this type of analysis. This would include not only process thermal energy and shaft energy, but pumping requirements and electrical power as well. 

If possible comparisons are focused on energy systems, nuclear power safety is also estimated to be superior to all electricity generation methods except for natural gas (30). Figure 3 is a plot of that comparison in terms of estimated total deaths to workers and the pubHc and includes deaths associated with secondary processes in the entire fuel cycle. The poorer safety record of the alternatives to nuclear power can be attributed to fataUties in transportation, where comparatively enormous amounts of fossil fuel transport are involved. Continuous or daily refueling of fossil fuel plants is required as compared to refueling a nuclear plant from a few tmckloads only once over a period of one to two years. This disadvantage appHes to solar and wind as well because of the necessary assumption that their backup power in periods of no or Httie wind or sun is from fossil-fuel generation. Now death or serious injury has resulted from radiation exposure from commercial nuclear power plants in the United States (31). 

Fig. 3. Total deaths pei 100 MWe-yr as a function of energy system. The space above the dashed line in each bai lepiesents the range of uncertainty in each...

Utilization of the conversion systems should not cause more environmental problems than other competing energy systems. 

In the United States, other experimental wave-energy systems have been investigated in California and Hawaii, including a 30-MWe heaving-buoy... 

Air Emission Tests at Commerce Refuse to Energy Facility, May 26—June 5, 1987, Vol. I, ESA 20522 449, Energy Systems Associates, Pittsburgh, Pa., July 1987. 

Iron—Air Cells. The iron—air system is a potentially low cost, high energy system being considered mainly for mobile appHcations. The iron electrode, similar to that employed in the nickel—iron cell, exhibits long life and therefore this system could be more cost effective than the ziac-air cell. Reactions iaclude ... 

Fig. 1. Volume change in anisotiopic giaphite during General Electric Test Reactor (GETR) irradiations. Courtesy of Oak Ridge National Laboratory, managed by Martin Marietta Energy Systems, Inc. for the U.S. Department of Energy under Contract No. DE-AC05-840R21400.

Fig. 6. Schematics showing the principal equipment components for the energy systems shown in Figure 5. (a) through (d) correspond to Figure 5a...

Steam. The steam system serves as the integrating energy system in most chemical process plants. Steam holds this unique position because it is an exceUent heat-transfer medium over a wide range of temperatures. Water gives high heat-transfer coefficients whether in Hquid phase, boiling, or in condensation. In addition, water is safe, nonpolluting, and if proper water treatment is maintained, noncorrosive to carbon steel. 

Other Energy Systems. Chemical plants usually require cooling water, compressed air, and fuel distribution systems. Sometimes also included are refrigeration, pressurized hot water, or specialized heat-transfer fluids such as Therrninol Hquid or condensing vapor. Each of these systems serves the process and reflabiUty is the most important characteristic. Thus a project in any of them that achieves a 10% reduction in energy cost at the expense of a 1% loss of rehabihty loses money for the operation. 

The purpose of this subsection is to introduce the reader to the tech-niqiies and methods used to recover materials, conversion products, and energy from solid wastes. Topics to be considered include (I) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recoveiy systems, (4) recovery of biological conversion products, (5) therm processes, and (6) waste-to-energy systems. 

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