Scale Inhibitor Testing at East Mesa

Abstract

A pilot scale test facility was used to test four calcite scale inhibitor chemicals. The test facility was designed to reproduce process conditions of the 43 MWg GEM 1 power plant, which utilizes moderate temperature geothermal fluid from pumped wells and dual flash steam separation at the power plant. The two most effective inhibitors were selected by simple, 24 hour atmospheric flash tests; they were tested more extensively in a dual flash test configuration which modeled actual plant flash conditions. Additionally, laboratory tests were conducted to determine the effective longevity of the inhibitor chemicals. Monsanto Dequest 2060, a phosphonate based product, was most effective at preventing scale formation, and was also most effective at delaying calcite precipitation at reservoir temperatures for up to 20 house. These results are consistent with previous work by other authors.