Utilizing IDDP‐1 fluid Sigurður H. Markússon Landsvirkjun Well IDDP‐1 › Well IDDP‐1 was the first well in the IDDP project › Planned for depth of 3,5‐4,5 km into supercritical conditions › Intersected magma at 2100 meters › Flow tested 2010 and 2011 › The well is very powerful, but the fluid corrosive (HCl) IDDP‐1 › After number of mechanical issues in 2011 the well is now flowing in restricted mode (8‐12 kg/sec) at 450°C and 138 bar › Capable of 50 kg/sec (+30 Mwe) IDDP‐1 fluid The steam is superheated. When it condenses it forms water with pH 2,5‐3 › Highly corrosive. Not suitable for carbon‐ or stainless steel Solid particles › Iron dust (Fe3O4, FeCl2) › Silica dust 4 5 Superheated steam 6 Experiments 2011‐ The key for further development Acid scrubbing How to remove the acid component Material testing What materials can handle the hot acidic fluid? Is there any corrosion when steam is superheated? Corrosion – Erosion? 7 IDDP‐1 fluid scrubbing › Removal of HCl gas › Common practice in various industries › Wet scrubbing › Dry scrubbing › Wet scrubbing › Water injected into the superheated steam › Acid forms in the water phase › Water is separated from the steam › Dry scrubbing › The steam flows through a bed of minerals or chemicals that capture HCl e.g .calcite › Has not been tested at such a high superheat 9 Wet scrubbing Water injected into the steam flow Steam suitable for use at power plant Steam + HCl(g) Scrubbed water Wet scrubbing experiment Wet scrubbing experiment Wet scrubbing results Steam can be scrubbed with available water › Brine, condensate from power plant or local ground water › HCl is easily removed by water › NaOH for improved efficiency › Elemental sulfur formation in condensate › Solid particles (dust) removed by the water phase › Full size equipment under development Low cost – robust method Material testing Challenging environment calls for new approaches in material selection: › Carbone‐ and stainless steel is not suitable for HCl environment › 254 SMO, titanium, Super alloys e.g. Hastelloy, inconel 625 › Ceramics, teflon..... › Behavior of wellhead/casing material at 450°C / 140 bar is poorly known Experiments 2011‐2012 › Corrosion under superheated conditions › Corrosion when steam condenses › Erosion resistance of materials 14 Material testing Erosion Corrosion at superheated conditions Heat exchanger – material testing Material testing – silica precipitation Silica › Silica particles › Volatile silica and dust is causing problems running experiments and precipitates on orifices and pipes › Not feasible to get solid silica in the steam gathering system and injection wells › Number of experiments planned for 2012 aimed at understanding silica and removal › Solubility of silica in steam › Orifices design (pressure drop vs precipitation) › Dry collection in settling tanks › Cyclone separators › Two stage wet scrubbing New challanges By utilizing fluid from the roots of the geothermal systems (400°C +) we are leaving the „comfort“ zone that has been created for the past 40 years › › › › › › Volatile compounds Traditional materials do not work Measurements Sampling methods Wellhead and casing design High rewards. 3‐4 wells per power plant? And IDDP‐1 is a major milestone 18 Summary › The steam is not harmful at high superheat but when it condenses it becomes highly corrosive › Wet scrubbing is easy and robust method for acid removal › Silica dust and volatile silica are the main challenges › Higher temperature – increased formation of volatile compounds (Si and HCl) › Challenging project offering great potentials Takk fyrir
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