| Title | Integrated Fluid-Chemical Monitoring Systems for Geothermal Applications |
|---|---|
| Authors | Harald MILSCH, Ronny GIESE, Mathias POSER, Simona REGENSPURG, Stefan KRANZ |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | geothermal, fluids, chemistry, scaling, corrosion, monitoring |
| Abstract | Two versatile fluid-chemical monitoring units have been developed for both low and high enthalpy geothermal systems. They enable online and in-situ measurements of a variety of physico-chemical parameters at different locations of a geothermal fluid loop above ground. The scientific and technical purposes of the systems are (a) to monitor a compositional variability of the produced fluid and (b) to understand chemical processes potentially occurring within a geothermal plant. The latter may result from reactions between fluid and surrounding materials and/or mineral precipitation, e.g. in the course of a temperature decrease or oxygen contamination. This information is of paramount importance as so induced reactions might lead to failure of plant components through corrosion and scaling and/or damage the reservoir’s permeability upon fluid reinjection and thus decrease injectivity. Within the fluid loop above ground a number of locations can be defined where fluid-chemical monitoring is of interest, e.g. before and after the degasser, the filters and the heat exchanger. The monitoring units can be set up close to these installations and permit selective fluid bypass and monitoring through solenoid valves. The fluid passes through tubings from one device or sensor to another until it is pumped back into the main fluid line right before the injection pump. Sensors are provided for pressure, temperature, volumetric flow-rate, density, sonic velocity, turbidity, pH-value, redox potential, oxygen content and corrosion monitoring. Additionally, fluid samplers have been installed to collect fluid and analyze the solution composition. All analytical devices are mounted on racks allowing easy transfer of the apparatuses to other geothermal sites. The maximum operating pressure and temperature of the units are up to 20 bar and 200°C, respectively. Both apparatuses can also be connected to allow stand-alone detailed process investigations on in situ or synthetic fluids at defined pT-conditions. In our contribution we will present details of the systems including their implementation into plant installations and/or their joint use as research devices, respectively. |