Modeling H2S Dispersion from Proposed Menengai Geothermal Powerplant

Abstract

The Hydrogen sulfide gas released from the geothermal operations has a potential impact on the health of the workers and the community living within the vicinity and also the geothermal equipment. Similarly, this gas is a toxic pollutant when released into the atmosphere. Additionally, this gas is corrosive to metal-based materials including brass and iron when dissolved in water. In this regard, there is need to manage the concentrations of hydrogen sulfide in the atmosphere at acceptable levels without detrimental effects to components of the biosphere. In this study, a dispersion modeling of H2S emission was used to assess the concentrations of hydrogen sulfide within the vicinity of the power plant. The technique is carried out using atmospheric dispersion modeling system (AERMOD) which is a steady-state Gaussian model to determine the hydrogen sulfide concentrations in the atmosphere within the vicinity of the power plant. To achieve this goal, hourly meteorological data were captured and input to the Aermet processor. Since weather conditions heavily influence H2S concentration, statistical analysis is used to determine a correlation between the weather parameters and H2S concentration. The analysis provided a mechanism used in predicting the concentrations of H2S under different weather conditions. As such, it provided a basis to determine the likelihood of conditions that may exceed the recommended concentrations and their potential effects on the environment. . The prepared background and predictive model when combined show that although operations at Menengai Geothermal Project emit H2S gas, the concentrations are below the WHO set guidelines of 150 μg m-3 and therefore have a less impact on air quality. The findings are beneficial as part of regulations for air quality standards to reduce global warming and environmental degradation, the introduction of H2S abatement techniques and reduction strategies.