| Popis: |
Geothermal Loop Experimental Facility (GLEF), located at Niland in the Imperial Valley, California, began operation in May 1976. The GLEF incorporates a sequential four-stage flash process to successively lower temperatures and pressures with a binary fluid energy-conversion cycle. Approximately 300 hr of intermittent operation were logged before shutdown of the facility for inspection and maintenance. Samples of the brine, suspended solids, and scale deposits were analyzed for bulk composition and mineralogy, but correlation with temperature and pressure is vague. In general, a galena-rich scale is observed in valves and piping ahead of the first-stage separator, becoming much less abundant beyond that point. The bulk of the scale consists of an increasing proportion of an iron-rich amorphous silica with process progression. Trace crystalline phases, such as akaganeite, kutnahorite, and sphalerite and/or wurtzite, have been detected or are strongly suspected in the scales. Halite and sylvite are found primarily as a result of numerous facility shutdowns and subsequent cooling of the retained brine in the equipment. Barite is frequently present when irrigation water (used for priming the wells) containing SO/sub 4//sup =/ is mixed with the brine. Calcite and/or aragonite is also found whenever separated steam condensate in contact with CO/sub 2/ more » is recombined with the brine. Corrosion products, magnetite and hematite, form an integral part of the scale adjacent to steel walls. The scales are layered with bands of widely differing material. The color, texture, hardness, and thickness of the deposits also vary considerably within locations in the GLEF. A new method of in-process scale buildup surveillance based on radiography was successfully verified. « less |
