Journal of Energy Engineering

Process waters collected during a Department of Energy in situ tar sand extraction experiment near Vernal, Utah, were characterized as having a high level of emuslified bitumen, exhibiting toxic properties and possessing low levels of inorganic constituents. Various coagulants were employed in an attempt to destabilize this emulsion. Ferric chloride was found to be most effective in that more than 98% of the emulsion was removed as total organic carbon (TOC) by this treatment and over 99% was removed as suspended solids. Increased toxicity levels were measured, however, in these treated effluents. Additional treatment by activated carbon adsorption removed these toxic components. Gas chromatography/mass spectrometry (GC/MS) analysis, using a modification of the U.S. Environmental Protection Agency (EPA) method 625, showed an estimated 2,000 compounds in the untreated process water. Coagulation reduced this to 72 identifiable components while activated carbon adsorption lowered this to six, including internal and recovery standards. GC/MS was unable, however, to identify a relatively significant series of materials shown to exist by TOC analysis which apparently had low vapor pressures and could not be analyzed by gas chromatography. The source or sources of the residual toxicity is assumed to be contained in these unidentified materials.

Short‐rotation intensive culture (SRIC) is a method of producing wood energy feedstocks that is potentially competitive with conventional wood sources in eastern Kansas. Silver maple is used as a representative energy species to examine alternative cutting cycles and planting densities. The sensitivity of discounted average cost is also evaluated with respect to changes in biomass productivity and to changes in production and harvesting costs. The results show that SRIC wood feedstocks can be grown, harvested, and delivered at costs approaching $50/dry tonne. This cost is nearly competitive with prices of delivered wood chips from conventional forest sources in eastern Kansas.

Research to develop a probabilistic model and methodology for aeolian fatigue design of overhead conductors that makes use of S‐N and “Load”‐N design curves is described. The probability‐based design equations and methodology use the mean and variance data of the S‐N and “Load”‐N curves to evaluate the reliability of overhead conductors subjected to aeolian fatigue. Even though the developed equations do not provide exact reliability levels, the values obtained allow rational decisions to be made on the basis of comparison with known safe levels of reliability. Using data available for 12 Drake Aluminum Conductor Steel‐reinforced (ACSR) Georgia Power Company lines, the simplified probabilistic design approach yielded probabilities of fatigue failure from 0.006% to 30%. Hence, the probabilistic model did predict aeolian fatigue problems for some of the lines using a 1% acceptable probability of failure.