Geochemical modelling of heavy metal deposition in a geothermal heat exchanger

Abstract

Heavy metal deposition and corrosion of carbon and low alloy steels exposed to geothermal two-phase fluids and brine solutions under acidic fluid conditions have been widely reported. Similarly, near neutral conditions can result in the precipitation of arsenic and antimony scales that can limit heat exchange. Geochemistry modelling has been undertaken to explain observed deposition and scaling in a two-phase geothermal fluid heat exchanger with a view to predicting the risk of heavy metal deposition and corrosion and heavy metal scaling in geothermal process fluids for new and existing energy facilities. Understanding of the geochemical parameters that control deposition, scaling and corrosion will allow the prediction of the risk of heavy metal deposition and scaling at the design stage for geothermal energy plants and assist in the selection of materials and processes that will give reliable long-term performance. The developed models have application in other industries for prediction of risk of scaling and corrosion and for process development support for example for the gettering of heavy metals from contaminated liquids and soils.