| Title | Failure Analysis and Mitigation of Corrosion on Condensate Reinjection Pipeline in Wayang Windu Geothermal Power Plant |
|---|---|
| Authors | G. Ganjar Zatnika, S. Wisanto, A. Wityasmoro, D. Kurniadi, A. Zein |
| Year | 2016 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Geothermal, failure analysis, reinjection, condensate, oxygen corrosion, HDPE, pipe stress analysis. |
| Abstract | Corrosion on reinjection pipelines has been renowned as one of the most challenging problem in geothermal plants as also found in Wayang Windu plant. A systematic failure analysis, design appraisal, and corrosion mitigation program have been carried out to investigate and alleviate thinning and leak failures on the condensate pipeline. Failure analysis by carrying out chemical characterization of corrosion products using X-ray diffractography, chemical analysis of condensate fluid, and field observation revealed that the failures had been likely caused by oxygen corrosion. The counteractions toward this corrosion issue have been conducted by both partial pipe spool repairs and total replacement with a non-metallic material as short and long term mitigation program, respectively. The latter program has been successfully accomplished by consecutively performing feasibility study, material selection, engineering design, installation, and testing. As a result, a new 4-km pipeline has been installed properly from a newly-established material of high density polyethylene (HDPE) to replace the failed existing steel pipeline. The HDPE was deliberately selected as the optimum material in comparison with Polyvinylidene Fluoride (PVDF), Chlorinated Polyvinyl Chloride (CPVC), and Polypropylene (PP). A pilot and comparative pipeline design were applied especially for the pipe stress analysis which became a hallmark of the thorough projects to conceive a proper supported above-ground HDPE pipeline. Moreover, the HDPE pipeline was installed by butt fusion joint which had been qualified by destructive tests comprising tensile tests and macroscopic observation as well as by field hydrotest. In addition to effectively mitigate the corrosion problem, this replacement has enriched the above ground facility with the application of corrosion-free and low life-cycle cost HDPE pipes as an alternative material in geothermal power plants. |