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W ...J 0) W However., a recent study completed at Utah State University explored the technic~l feasibility of these important questions [13]. The study examined in some detail the chemical interactions between water of varying'sa1inities (TDS range 3,000 to 10,000 mg/L) and the coal matrix. Experimental test results reflected complex interactions between the saline ~ater media and the coal matrix. In some cases, chemical consti- tuents were leached from the coal; in others, constituents were absorbed by the Coal. The study concluded that coal slurrying with saline water is a technically feasible alternative to using good quality water as a transport medium. In other studies of the technical and operational feasibility of using saline water in coal slurry pipelines, several interesting considera- tions were explored. One study generally concluded that the concentra- tion of ' contaminants in saline slurry water is increased due to contact with co~l [18]. The major increases were in TDS, total hardness, sulfate, magnesium, and sodium. Since the coal would not be dewatered comp1et~ly, a high chloride content might result in wet scrubber corro- sion. Oissolved sodium salts could also affect the operation of the coal-fired boiler its~lf. It is known that increasing the salt content of the qoal, as fired, has the adverse effects of increasing fouling in the boiler and impairing the ability of the deposited ash to harden, On the oth~r hand, it has been found that the addition of sodium sulfate to coal has improved the performance of hot-side electrostatic precipita- tors on ;boilers and furnaces when burning low-sulfur, low-sodium coals. Where t~e dissolved solids in the saline water slurry are largely sodium chloride, the general corrosivity of the slurry would be increased and corrosion inhibitor injection may be required to protect the pipeline itself. After s~paration of coal and water at a terminus location, the water after t~eatment could be used for other purposes. Such purposes would include cooling towers, ash disposal, or possibly solar salt gradient ponds. ' 4. Sa]ti Grad i ent So 1 ar Ponds Saline water from the Upper and Lower Colorado River Basins provides an opportunity to produce electric power and freshwater by utilizing the brines for nonconvecting solar ponds. Salt gradient solar ponds, coupled to closed-cycle, open-cycle, or thermoelectric conversion power geheration processes, could produce electric power at costs competitive with conventional sources, It is estimated that approxi- mately 10 percent of the electric power needed in the United States can be supplied by solar ponds located in the southwest, The electric output can be integrated with the grid or, alternatively, combined thermal and electrical energy can be used with appropriate desalination processes to produce freshwater [21], The thermal e~er~y su~plied by a pond could be used directly in a low temperature dlstll1atlon process or in a thermally regenerated ion IV-25 :1 ':<, '..1 ~" ~ ,,;-