Anyone admiring the brilliant white travertines of Pamukkale is in fact watching something a geothermal engineer deals with every day: calcium carbonate precipitating out of hot water. In Denizli, this natural spectacle and industry share the same chemistry. Turkey’s first geothermal power plant came online in 1984 at the Kızıldere field in Sarayköy, and today the region uses geothermal energy not only for electricity but also for heating and thermal tourism.
How travertine forms, and why scale is the same thing
The hot water feeding Pamukkale carries plenty of dissolved CO₂ and calcium under high pressure underground. When the water reaches the surface, pressure drops, CO₂ escapes to the air, pH rises and calcium carbonate can no longer stay in solution. The result is the white travertine building up along the terraces.
This is exactly what happens in a production well. As the fluid rises, it starts to boil (flash) at a certain depth, CO₂ moves into the gas phase and calcite deposits just above the flash point. Terraces that took centuries to form at Pamukkale become, inside a well, a scale layer that can cut flow within a few months. For the mechanism in detail, see our guide to calcite scaling.
From Kızıldere to today: high temperature, high gas
The Denizli fields lie at the eastern end of the Büyük Menderes Graben. Kızıldere is one of Turkey’s high-temperature fields, and its fluids are known for their high CO₂ content. Together, these features require operators to focus on three areas:
- Downhole calcite control: continuous delivery of scale inhibitor below the flash depth through a capillary tube. See downhole dosing.
- Silica management: as steam separates, silica concentrates in the remaining brine, creating a risk of silica scale in cooled lines and at reinjection. See silica scaling and reinjection line.
- Corrosion: dissolved CO₂ and H₂S accelerate corrosion of carbon-steel equipment. See geothermal corrosion.
Beyond power: heating, greenhouses and spas
In Denizli, geothermal energy is used not only in power plants but also for residential heating, greenhouses and thermal facilities around Sarayköy, Buldan and Karahayıt. The fluid in these systems is cooler, but calcite scale in plate heat exchangers and oxygen-driven corrosion in closed loops are common. Regularly tracking the heat exchanger approach temperature is the easiest way to catch fouling before cleaning becomes necessary. More: geothermal heating and greenhouses.
The measurements that make a programme work
- Calcium and alkalinity at the wellhead: if calcium stays in the fluid, calcite inhibition is working.
- Flow rate and wellhead pressure: early signs of bore restriction.
- Total and monomeric silica: the tendency of silica to polymerise.
- Corrosion coupons and probes: the level of protection the programme delivers.
- Residual inhibitor concentration: whether the dose is sufficient, avoiding unnecessary chemical use.
Working in Denizli with Biyopol Kimya
The Denizli fields are easy to reach from our plant in İzmir, so we can manage sampling, pilot trials and regular deliveries closely. With BiyoGeo CS scale inhibitor, BiyoGeo CI corrosion inhibitor and BiyoGeo HX heat exchanger conditioner, developed through TÜBİTAK-supported R&D, we build each programme around the field’s own fluid analysis. Our regional approach is on the Denizli geothermal fields page; all solutions are on geothermal power plant chemicals.
Would you like an assessment for your well or heat exchanger? Contact us through the quote and sample request form.