| Title | Removal of Hydrogen Sulfide and Recovery of Carbon Dioxide From Geothermal Non-Condensable Gas Using Water |
|---|---|
| Authors | Mamrosh, Darryl; Mcintush, Kenneth; Douglas, Austyn; Fisher, Kevin; Juliusson, Bjarni; Gunnarsson, Ingvi; Markusson, Sigurour; Matthiasdottir, Kristin; Arnarson, Magnus |
| Year | 2014 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Noncondensable gas; NCG; H2S abatement; hydrogen sulfide removal; CO2 recovery; Iceland |
| Abstract | A collaboration of geothermal power plant operating companies in Iceland is developing a water absorption technology that enhances the selectivity for hydrogen sulfide removal from noncondensable gas (NCG) that is rich in CO2. Cool water is used to absorb the H2S on a once-through basis, and the H2S-containing water would then be injected into a suitable underground reservoir. Operation of the absorption at significantly elevated pressure (~5 bar or higher) is required in order to allow for water to have a reasonable solubility for the H2S. Two varieties of this technology were considered, one in which a flash of the absorption column bottoms is used to increase the H2S absorption selectivity, and one in which a reboiler is applied to the absorption column bottoms. Process simulations were used to estimate the performance of this concept for six geothermal power plants in Iceland, with the reboiled method preferred due to the availability of low-value heat from hot brine. In addition to H2S removal, the recovery of CO2 products from the NCG (after the H2S is removed) was also considered. Conceptual designs were developed for recovery of low purity CO2 gas and higher purity liquefied CO2 products. |