Formation Mechanism and Control Techniques of Calcium Carbonate Scale in Langjiu Geothermal Field, Tibet

Abstract

Calcium Carbonate Scale is one of the puzzles which must to be solved during the process of mass production in Middle-high Temperature Geothermal Field. The formation trend of the Calcium Carbonate Scale in Langjiu Geothermal Field of Tibet is obvious. The speed of the scaling is 2mm/d. In this paper, based on the research of geothermal geologic conditions in the area and formation characteristics of the geothermal fluids, we considered that the inherent mechanism of Calcium Carbonate Scale formation is the catalyst precursors of supersaturated solution—the coherence transformation of solubility between aragonite-calcite. The external condition is the mixture of the deep geothermal fluids and the cold surface water, which occurred after the pressure decreased. According to the scaling controlling and scaling removal in the discharge-spray tests, we put forwards that the first choice of scale controlling is the combination of compression and the resistance scale agent which is the series of phosphate molybdenum addition. And the first choices of the scale removal are mechanical scale removal and chemical scale removal.