Rolled Lined Corrosion Resistant Steel Pipes in Geothermal Environment: Investigation and Results of Field Tests

Rolled lined corrosion resistant steel pipes in geothermal environment: Investigations and first results of field tests

 George Furmanski, Kam Dianatkhah             CalEnergy, Calipatria, California

Bernd Berg, Dr. Ulrich Schnaut                      Bergrohr GmbH Siegen, Germany

 

 In order to meet the severe corrosion requirements of CalEnergy’s geothermal environment, a new type of corrosion resistant rolled lined steel pipes were tested in the laboratory and  geothermal field.  

 Providing an optimized reliable and cost efficient solution with respect to the prevailing types of SCC and pitting corrosion, this innovative and efficient pipe manufacturing process allows for the first time application of liner materials such as Duplex Stainless Steel (2205) and Super Duplex Stainless Steel (2507) as well as Alloy 625® for lined steel pipe. The corrosion resistance performance of rolled lined pipes is due to a mechanical bond with high gripping force between liner material and carbon steel. The liner ensures full corrosion and erosion resistance and the backing steel provides the mechanical properties such as pressure resistance.

 After a short description of the innovative pipe manufacturing process, the paper will present results and data provided by Scanning Electron Microscopy (SEM), X-ray fluorescence (XRF) and chemical analysis of geothermal brine, corrosion and scale products. This test program also compares laboratory corrosion tests vs. Field corrosion behaviour of the Clad alloys under real conditions.