Magnesium-silicate scaling in mixture of geothermal water and deaerated fresh water in a district heating system

Journal Article · Sat Dec 31 23:00:00 EST 1988 · Geothermics; (USA)

DOI:https://doi.org/10.1016/0375-6505(89)90017-5· OSTI ID:5323535

Gunnlaugsson, E ^[1]; Einarsson, A ^[2]

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1. Hitaveita Reykjavikur, Grensasvegur 1, 108 Reykjavik (IE)
2. Fosshals 3, 110 Reykjavik (IE)

The low-temperature geothermal fields in Reykjavik utilized by the Reykjavik Municipal District Heating Service are now fully exploited. Additional hot water will be obtained by heating and deaerating fresh water using high temperature geothermal fluid. The heated fresh water will mix with low-temperature geothermal water in the distribution system in Reykjavik. A pilot plant has been set up to investigate magnesium silicate scale formation when mixing of these waters occurs. Tests show that the scale formation is dependent on the severity of deaeration of the fresh water the proportion of geothermal water in the mixture. Increased deaeration and thermal water proportion increase the pH of the mixture, and this promotes scaling. The scale formed is poorly crystalline, near amorphous trioctahedral smectite close to saponite in composition. By using minimum deaeration and traces of geothermal steam to remove the last remaining dissolved oxygen, scaling in the distribution system can be avoided.

• OSTI ID: 5323535
• Journal Information: Geothermics; (USA), Journal Name: Geothermics; (USA) Vol. 18:1; ISSN GTMCA; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150800* -- Geothermal Power Plants
150903 -- Geothermal Engineering-- Corrosion
Scaling & Materials Development
151000 -- Geothermal Energy-- Direct Energy Utilization
ALKALINE EARTH METAL COMPOUNDS
CORROSIVE EFFECTS
DISPERSIONS
DISTRICT HEATING
ELEMENTS
FLUIDS
FUNCTIONAL MODELS
GEOTHERMAL DISTRICT HEATING
GEOTHERMAL FIELDS
GEOTHERMAL FLUIDS
GEOTHERMAL HEATING
HEATING
LOW TEMPERATURE
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MIXTURES
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
PILOT PLANTS
SCALING
SILICATES
SILICON COMPOUNDS