Abstract
Geothermal energy is acknowledged globally as a renewable resource, which, unlike solar, wind or wave energy, can be continuously exploited. The geothermal fluids usually have some acid gas content, which needs to be precisely taken into account when predicting the actual potential of a power plant in dealing with an effective reinjection. One of the key parameters to assess is the solubility of the acid gas, as it influences the thermodynamic conditions (saturation pressure and temperature) of the fluid. Therefore, an enhanced solubility model for the CO2-H2S-water system is developed in this study, based on the mutual solubility of gases. The model covers a wide range of pressures and temperatures. The genetic algorithm is employed to calculate the correlation constants and corresponding solubility values of both CO2 and H2S as functions of pressure, temperature and the balance of the gas. The results are validated against previously published models and experimental data available in the literature. The proposed model estimates the pure gas solubility, which is also a feature of other models. The more innovative feature of the model is the solubility estimation of each CO2 or H2S in simultaneous presence, such as when the binary gas is injected into the pure water of the geothermal reinjection well. The proposed solubility model fits well with the available experimental data, with a mean deviation lower than 0.2%.
Highlights
Geothermal energy is generally recognised as a renewable resource, which is especially appealing because it is not hindered by the lack of constant resource availability, as is the case with solar, wind or wave energy
The current study introduces new correlations for the solubility modelling of pure CO2, pure H2 S, and the CO2 -H2 S mixture in water at a wide range of pressures and temperatures, which meets the requirement of geothermal modelling
The objective of the present study is the development of a model suitable for geothermal applications facing gas mixture solubility, where in most cases the gas is not pure
Summary
Geothermal energy is generally recognised as a renewable resource, which is especially appealing because it is not hindered by the lack of constant resource availability, as is the case with solar, wind or wave energy. Geothermal energy has a high power ratio (power over the covered surface area) and, due to the high drilling cost by a minimum of 2 M$/well [1], the power plant size typically ranges between 1 and 60 MWe. Careful management of the geothermal field can guarantee a significant lifetime (>25 years with more than 7500 h/yr of operational time) for the geothermal energy conversion system; in the long-term, the issue of sustainability is primarily linked to the reservoir fluid balance. The main issue, when shifted to the short-term and local scale, where relevant side effects are present, is the release of non-condensable gases (NCGs) to the environment. The contaminants released by geothermal energy conversion systems (GECS) usually include H2 S, NH3 , CH4 , and, in some cases, Hg [2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
