Ultrasonic and Impact-Echo Testing for the Detection of Scaling in Geothermal Pipelines

Abstract The efficiency and longevity of components in geothermal plants are significantly reduced by mineral deposition pipes, also known as scaling [1]. A number methods used to monitor fouling (a broader term for all types organic inorganic deposition) other industries, such the oil, gas food industries. These include direct indirect, offline, in-situ online, well inline methods, each which have pros cons [2, 3]. An effective monitoring solution specific high temperature conditions plants, optimises maintenance cleaning measures dependency scaling, has yet be developed. In this paper, two non-destructive testing techniques: contact ultrasonic (UT) impact-echo (IE) investigated their viability detect growth plants. descaling measurement was conducted on a heavily scaled segment an obsolete pipeline from production power plant Sauerlach, Germany. inserted test rig gradually etched away using acidic solution. At regular time intervals, thickness measured mechanically UT IE measurements were carried out. apparatus designed withstand temperatures ( $${140}\,^{\circ }{\text {C}}$$ 140 ? C at inlet pipe surface) easy install whilst being cost-efficient. Both techniques yielded usable results with submillimeter resolution. advantages limitations discussed. Impact-echo testing, particular, can automated presents simple cost-efficient option.