| Title | A process model for geothermal power generation |
|---|---|
| Authors | A. Choudhary, R. Rayudu, J. Hinkley, J. Burnell |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Geothermal, energy, gases, organic Rankine cycle, process model, wells, geothermal fluid |
| Abstract | Geothermal power plants utilize the heat from geothermal reservoirs to generate electricity. Geothermal fluid has some non-condensable gases brought to the surface during electricity generation. These gases mainly consist of carbon dioxide. There is an impact of these gases present in the geothermal fluid on the production well productivity, the heat transfer efficiency of heat exchangers, etc. Process models are considered powerful tools for understanding the working of geothermal power plants. The process models prepared are based on the specific components and given details of a geothermal system. The process model developed for this paper is a coupled wellbore and subsurface model of a geothermal power plant. Firstly, the wellbore model was developed using WELLFLOW, a wellbore simulator, and then the sub-surface model was developed using DWSIM, an open-source process modeling software. Both WELLFLOW and DWSIM can use Python scripting, which was utilized, and both models were coupled. The paper demonstrates a coupled process model calculating the fluid flow from the production well and the output from the geothermal power plant. The wellbore model provides the flow rate from the wellbore based on the wellhead pressure. The composition of the geothermal fluid is obtained from the reservoir data. The process model shows that for a given wellhead pressure, we can estimate the flow rate from the wellbore and the pentane required for an Organic Rankine cycle. The process model then provides us with the output from the turbine and the desired temperature for the reinjection fluid. |