Journal of Energy Engineering

A case history is presented in which foundation soils in excess of 50 ft (15 m) deep, were densified in place to the degree required to support the loads of a coal‐fired electric generating plant. The use of drop‐weight compaction and compaction grouting techniques resulted in a significant savings when compared to a more conventional pile foundation system. The application of deep densification techniques has gained increased popularity in recent years. However, even when the soil conditions on a major project are appropriate for in‐place densification, the implementation of a deep densification foundation plan may be difficult. A large portion of this difficulty is attributed to the required deviation from the traditional methods of site investigation, contract preparation and construction management. The case history considers how the foundation plan was developed to allow deep densification to be a viable foundation preparation alternative and, ultimately, part of a successful foundation system.

Upsets to Flue Gas Desulfurization (FGD) sludge treatment systems may occur under auto‐oxidation conditions. Auto‐oxidation is the appreciable natural conversion of ${\mathrm{CaSO}}_3\cdot 1/2H_{2}O$ to ${\mathrm{CaSO}}_4\cdot 2H_{2}O$ due to lower ${\mathrm{SO}}_2$ loading (less than 1.2 lb inlet ${\mathrm{SO}}_2/\mathrm{MMBTU}$) and operating pHs of lime/limestone FGD Systems. A 75–79% auto‐oxidized $(75-79\%{\mathrm{CaSO}}_4)$ FGD sludge exhibits a mean particle diameter of 45 microns—considerably larger than unoxidized $\left({\mathrm{CaSO}}_3\right)$ particles. The oxidized sludge reaches terminal settling velocity within 8–10 min, five times faster than unoxidized material. Auto‐oxidized waste settles in gravity thickeners to higher densities (0.85 g dry solids/ml) and to thicker underflows (40% solids). Rakearm overload and blanket consolidation can be avoided by proper drive mechanism design and underflow solids/density control, providing an 8 hr underflow surge/storage tank is recommended instead of thickener sludge blanket storage. Vacuum filtration of an $80\%{\mathrm{CaSO}}_4$ sludge yields 25% greater solids in the cake as compared to a 30% oxidized material. To avoid cake‐cracking, reduce the degree of vacuum during incidents of autooxidation and provide dual filtrate receivers. Using predictive curves presented here, a Transportability Analysis was performed on a coal of 0.59–0.91% sulfur and of 10.00–21.50% ash. At an ${\mathrm{SO}}_2$ loading of 1.08 lb/MMBTU 38% solids (thickener underflow) or 63% solids (filter cake) could be achieved. Either filter by‐pass or adding less fly ash to the cake permits achieving a 75–85% solids transportability blend. Auto‐oxidized sludge/ash blends exhibit unconfined compressive strengths from 57–63 psi and permeabilities from $2.2-3\times {10}^{-5}\mathrm{cm}/s\text{.}$

The potential of a salt‐gradient solar pond for electric power production and thermal energy supply for cooling, using absorption chillers, and heating of a building was investigated by means of computer simulations. The analysis was conducted for the pond and building of the Energy Systems Center (ESC) located in southern Nevada. The experimental pond has a bottom area of about $950m^2$ and 3‐m depth. The energy requirement for cooling and heating of the ESC $232-m^2$ two‐story building was calculated using the TRNSYS model and the ESC facility data. Power production from the pond was evaluated for a solar pond power plant with a low temperature Organic Rankin Cycle (ORC) generator. Several operating strategies were simulated using the salt‐gradient solar pond (SGSP) model. The results indicate that the pond can produce 16.8 kWe for 10 h/day, sufficient for ESC cooling demands. Using a pond absorption chiller system for cooling, 27% of the energy available from the pond will meet the cooling and heating demands of the building.

Since the OPEC oil embargo, several utilities have reconverted or are in the process of reconverting some of their power plants from oil to coal firing. The increased quantity of wastes generated as a result of these projects, coupled with the requirements of the National Environmental Policy Act (NEPA) and the Resource Conservation and Recovery Act (RCRA), necessitates that the utilities develop comprehensive solid waste management plans. In most cases, the environmental licensing for these projects requires the preparation of a Draft Environmental Impact Statement, in which solid waste management impacts, as well as alternatives to disposal, are discussed. Frequently, other documents, similar to Environmental Reports, containing the results of the subsurface and groundwater investigation and accompanied by a set of conceptual design drawings, must be prepared to satisfy the licensing requirements for the selected solid waste management facility. While air quality impacts remain the single most important environmental consideration facing these reconversion projects, solid waste management plans are also vital to successful licensing. Proper attention to the solid waste management issues of a utility's coal reconversion project can expedite the licensing process and, consequently, the overall reconversion timetable. Several of the major aspects which should be considered when selecting and licensing a utility's solid waste management facility are discussed in this paper.

Design and construction of four containment buildings for the Limerick and Susquehanna nuclear power plants has shown that a reinforced concrete containment is feasible. Features of the containment, design criteria, methods of analysis, construction and testing of the containment buildings are presented. Special attention is given to innovations in the design and construction and suggestions are made for improvements in these areas.

A fixed‐material test pad was constructed to evaluate the long‐term effects of the fixation with lime of blended fly ash and scrubber sludge. The $507.9\times {10}^3\mathrm{kg}$ test pad was envisioned as a scale model disposal site with average dimensions of $13.72\times 22.86m$ by 0.76 m thick. The fixed material was tested at the time of pad construction in 1979 and again in 1983 when the present investigation was conducted. The study included field and laboratory evaluation of the physical and chemical properties of the four‐year‐old fixed scrubber sludge. The effect of the exposure of the material to the elements for four years is described, and based on these effects, recommendations on the proper disposal of this type of material in landfilling are made.

The conveyance capacity of the tunnel designed to move water from the Mediterranean Sea to a power station on the Dead Sea was calculated to refill the Dead Sea to its historic level at a rate which maximizes the project's net benefits. The generation capacity of the project was calculated to make optimal use of the amounts of water thus conveyed. In calculating the dimensions of these two main components of the scheme, as well as those of other facilities, the long‐term economic impact of the project on the entire Israeli national power system was evaluated. These studies formed part of the feasibility study which proceeded in parallel with outline design of the facilities. Both engineering and economic studies have adopted a rather conservative approach and included numerous iterations and sensitivity tests. The feasibility study concludes with a recommendation to implement the scheme on the grounds of direct quantifiable benefits only, even though there are several other benefits to the power system, and to the national economy in general.

The binding and trapping of glass and organics that occurs during the shredding of municipal solid waste (MSW) is examined experimentally. Such glass is called bound glass. This process produces feed which detrimentally effects air classifier production of refuse derived fuel (RDF). Glass contaminated RDF causes excessive slagging on incinerator walls and abrasion of mechanical parts. Results indicate that the glass prticle size distribution produced by the shredder and the moisture content in the waste steam effect bound glass amounts. Further, bound glass increases with moisture content and increases with decreasing particle size. Dry waste streams and shredders which produce large glass particles are suggested to produce better feeds for air classifiers, and consequentially better RDF.