Abstract
Membrane distillation (MD) and nanofiltration (NF) are explored as a means to provide high quality water for on-site use at the Tuscarora geothermal power plant in northern Nevada. The plant uses a wet cooling tower, but decreasing flow from the wells providing makeup water necessitates exploration for alternative water or alternative cooling sources. Scenarios are explored to extend cooling water by (1) extracting fresh water from the geothermal brine, (2) upgrading the makeup-water quality to allow for increased cycles of concentration in the cooling tower, or (3) recovering water from the cooling tower blowdown. The preliminary cost analysis indicates that applying NF to extract water from the injection brine is the most attractive option of the scenarios examined. This approach may be useful for other plants as well. The estimated cost for the NF treatment of the injection brine ranges from $0.63/m3 to $0.45/m3 and provides a reduction in the current makeup well flows of 35% to 71%. Savings from the reduction in makeup well pumping and chemical treatment do not fully offset the estimated cost of the proposed treatment systems; the site will have to weigh the cost of these water treatment options versus alternatives in light of the diminishing flows from the existing cooling-water wells. Testing is planned to quantify the performance of the proposed NF and MD technologies and help refine the estimated system costs.
Original language | American English |
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Pages | 258-276 |
Number of pages | 19 |
State | Published - 2017 |
Event | Geothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017 - Salt Lake City, United States Duration: 1 Oct 2017 → 4 Oct 2017 |
Conference
Conference | Geothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017 |
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Country/Territory | United States |
City | Salt Lake City |
Period | 1/10/17 → 4/10/17 |
NREL Publication Number
- NREL/CP-5500-68502
Keywords
- Desalination
- Direct use
- Low-temperature geothermal
- Membrane distillation
- Nanofiltration