Increase the Efficiency of Pumping Spa Water From Glauber Salt Spring
Progressing cavity pump conveys healing water with a high brine content
High brine content, sodium sulphate, and chloride levels attack the systems, and the demands on pumps for conveying healing water are high. As a global specialist in complex fluid management, NETZSCH Pumps & Systems has sophisticated solutions for pumping spa water.
We will show you how to pump healing water with a high brine content efficiently and gentle simultaneously by using a progressing cavity pump with a drive unit at the surface.
Efficient pumping of spa water with high brine content from the depths
There are various reasons for wanting to pump water from great depths to the surface. On the one hand, this water can be used for geothermal purposes under optimal conditions. On the other hand, media are suitable as healing water for thermal baths due to their composition. The latter includes water with a high brine content. However, this poses significant challenges for pumps due to the ingredients. The original goal of the Saxony State Spa was to explore and develop brine exclusively for geothermal purposes. After a suitable location was found in the Elster Valley using exploration, i.e. a geophysical survey of fault zones, an exploratory borehole was drilled at a depth of 1,200 m, and a first pumping test was carried out.
High sodium sulphate and chloride content demand healing water pumps
During the exploratory drilling, those responsible came across highly mineralised water with exceptionally high sodium sulphate and chloride content. Due to the mineral content of the healing water, a special pump was needed to transport the medium gently to the surface. The aim was to cover the water demand of three pools in the thermal brine bath with a capacity of 450 cubic metres of healing water. In addition to the composition of the healing water, the challenge was to find a pump that would efficiently bring the fluid, which is unique in Germany, to the surface from a depth of 1,200 metres in the Elster Valley.
Progressing cavity pump conveys healing water flexibly and efficiently
NETZSCH developed an innovative solution for pumping the spa water based on a downhole system initially designed for pumping in oil fields. Thanks to years of experience in the oil and gas sector, the solution was obvious to the global specialist in complex fluid management. Due to the borehole's small diameter of 95 millimetres, a progressing cavity pump with a drive unit at the surface was chosen. The advantage of this solution for pumping the healing water also lies in its rapid availability and maximum flexibility in the delivery rate and the medium to be pumped. No other pump system can cover such a wide range of delivery rates. For this reason, this pump technology is being used more and more frequently, especially during test phases.
Using a heating jacket for the pump, you can also heat the brine and dissolve more salt. To prevent the salt from crystallising and abrading the elastomer during pumping, the spring water was pumped with a brine content of 22 percent, i.e. diluted, and at a temperature of 42 °C. The brine was then pumped at a temperature of 50 °C. The speed of the progressing cavity pump was 100 to 200 revolutions per minute. This used the natural lubricating effect that brine exerted at higher flow rates and avoided elastomer abrasion. Since the unit has only a small number of wearing parts, life cycle costs are kept low. This significantly reduces your maintenance and servicing costs. However, it is not only the operators of the state spa who benefit from using the progressing cavity pump to pump the healing water to the surface. Visitors to the 4,500-square-metre spa landscape also enjoy various pools in which the brine is used in diluted form, allowing them to float weightlessly in the water. For example, there is a salt lake with a brine concentration of 15 percent and two pools with a brine content of ten and six per cent, respectively.