Energy and CO2 Emissions Penalty Ranges for Geologic Carbon Storage Brine Management

Shale Gas Decarbonization in the Permian Basin: Is It Possible?

The United States is unique in the energy reserves held in shale gas fields, which coproduce natural gas and natural gas liquids. Use of this resource, however, contributes to greenhouse gas emissions and, correspondingly, climate change. We explore how natural gas and natural gas liquids might build bridges toward low-carbon transportation fuels. For example, as petroleum refineries produce less gasoline in response to widespread electrification, natural gas liquids can be converted to fuel. We consider whether the greenhouse gas emissions from production and use of these fuels might be offset through three potential outcomes of converting coproduced natural gas to CO₂ through steam methane reforming. First, the CO₂ could be injected into conventional oil formations for enhanced oil recovery. Second, it could be sequestered into saline aquifers to avoid CO₂ emissions from the produced oil combustion. Third, it could be injected into unconventional gas formations in the form of CO₂-based fracturing fluids. Simultaneously, the coproduced hydrogen from steam methane reforming could be used to support the expansion of the hydrogen economy. The region of study is the Permian Basin. The results show sizeable emission benefits by decreasing net emissions of natural gas production and use to 28 from 88 g-CO₂e/MJ. For revenue generating pathways, a partial decarbonization of 3.4 TCF/year is possible. All of the natural gas can be partially decarbonized if the CO₂ is sequestered in saline aquifers. Overall, the results show that while greenhouse gas emissions can be reduced through decarbonization approaches relying on subsurface sequestration, full natural gas decarbonization is not achieved but must be pursued through other approaches.

TiO2 Coating Strategy for Robust Catalysis of the Metal-Organic Framework toward Energy-Efficient CO2 Capture

High energy duty restricts the application of amine-based absorption in CO2 capture and limits the achievement of carbon neutrality. Although regenerating the amine solvent with solid acid catalysts can increase energy efficiency, inactivation of the catalyst must be addressed. Here, we report a robust metal-organic framework (MOF)-derived hybrid solid acid catalyst (SO42-/ZIF-67-C@TiO2) with improved acidity for promoting amine regeneration. The TiO2 coating effectively prevented the active components stripping from the surface of the catalyst, thus prolonging its lifespan. The well-protected Co-Nx sites and protonated groups introduced onto the TiO2 surface increased the amount and rate of CO2 desorption by more than 64.5 and 153%, respectively. Consequently, the energy consumption decreased by approximately 36%. The catalyzed N-C bond rupture and proton transfer mechanisms are proposed. This work provides an effective protection strategy for robust acid catalysts, thus advancing the CO2 capture with less energy duty.