| Title | REMOVING SILICA FROM GEOTHERMAL WATER - RE-DESIGN OF THE PILOT PLANT AND INVESTIGATION OF OPERATION AT ELEVATED PRESSURE |
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| Authors | T. Borrmann, M. Schweig, J.H. Johnston, M.J. Cairns and H.P. Fraser |
| Year | 2019 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Scale formation, silica scale, silica, calcium silicate hydrate, nano-structured calcium silicate hydrate, calcium carbonate, calcite, calcite scale, geothermal energy |
| Abstract | The nano-structured calcium silicate hydrate (CaSil) technology has been developed as a solution for the formation of silica scale from geothermal brine. It has been matured from laboratory scale to pilot plant stage. The CaSil technology is successful in reducing silica in geothermal water to safe usage and re-injection levels, even at low temperatures. However, while the initial version of the pilot plant built was useful as a proof of concept, it had several shortcomings. Namely it was work intensive, allowed little control over the products collected, and the separation process for recovery of CaSil from the brine was only designed to work at atmospheric pressure. Work on the first proof of concept plant proved that the process is very sturdy; none of the shortcomings had any significant impact on the plant operation. In this paper we present our pathway towards the next iteration of pilot plant, which will address many of the issues encountered in the old plant. We are also outlining further research towards using the separator technology under elevated pressure. |