| 摘要 |
A process and apparatus is provided for reducing the concentration of fine, residual solids still remaining suspended in clarified geothermal brine overflow from a primary brine clarification stage in which hot, flashed, silica-rich geothermal brine, containing suspended siliceous material, is gravity separated, comprises flowing the brine overflow from the primary clarification stage into a closed secondary clarifier vessel having an internal reaction well. Capacity of the secondary clarifier vessel provides a brine residence time in the vessel of between about 45 and about 150 minutes, the brine residence time in the reaction well being between about 10 and about 20 minutes. Brine in the vessel is blanketed with steam flashed from the brine to exclude air from the vessel. In the reaction well, the brine is contacted with a flocculating agent, such as a cationic, anionic, or non-ionic polyacrylamide having a molecular weight of at least about 1 million, in an amount of between about 0.25 and about 2 parts per million. An underflow slurry of flocculated siliceous solids and brine is discharged from the bottom of the vessel. An amount of such underflow slurry is recirculated back into the reaction well to cause the solids concentration in the well to be between about 0.5 and about 3 weight percent. A secondarily clarified brine overflow from the secondary clarifier vessel has a concentration of fine, siliceous material remaining suspended therein that is substantially reduced over the concentration of such material suspended in the brine overflow from the primary clarification stage.
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