Editorial Comment: A brighter future for methane hydrates?
Methane hydrates are three-dimensional ice-lattice structures in which natural gas is trapped. These hydrates are found both onshore and offshore, in ocean sediments along continental shelves and underneath the Arctic permafrost. When the hydrates are melted into water, methane molecules are released. The U.S. Geological Survey estimates that worldwide gas hydrates reserves are between 10 times and 100 times more plentiful than U.S. shale gas reserves, which are estimated at more than 342 Tft3 as of 2018.
However, the recovery of methane hydrates has been difficult, as the gas is locked in permafrost and often located in deepwater coastal areas. The high pressure that helps form methane hydrates must be maintained when the sediment cores are analyzed, or the hydrates will dissociate into water and gas. Also, concerns exist about how the potential release of methane emissions during hydrates extraction could impact the environment.
However, researchers recently announced a technological breakthrough that could boost the amount of methane hydrates recovered from permafrost, while decreasing the amount of greenhouse gas released into the atmosphere. An international team of researchers from Skoltech University in Russia and Heriot-Watt University in Scotland found that replacing the methane in the hydrates with flue gas from fuel combustion allowed for more efficient recovery of methane from permafrost.
An additional benefit of the process is the potential to use methane hydrates as carbon sinks. By locking flue gas in permafrost, the amount of greenhouse gas released into the atmosphere can be limited while simultaneously preventing the spontaneous release of methane. The research team used a CO2-based hydrate in flue gas to replace the methane hydrate, which allowed them to capture nearly 82% of the CO2 in the flue gas.
The study, published in November 2019 in Scientific Reports, stated, “In comparison with potential methods such as thermal stimulation, depressurization or chemical inhibitor injection, CO2 or CO2-mixed gases (e.g., flue gas) injection is more environmentally friendly because of the potential to capture CO2 simultaneously with methane recovery.”1
The new method could help Russia exploit its newly discovered oil and gas reserves in the Arctic, which have the potential to accidentally release significant quantities of trapped methane into the atmosphere. The emissions risk, along with a lack of infrastructure in the remote areas, is hindering Russia’s development of its Arctic reserves.
Japan is also targeting commercial production of methane hydrates—as much as 40 Tft3—although full-scale development of these resources is not expected to be achievable in the near term. The country is studying ways to control methane release from ice so that the gas flows directly into the production well, thereby maximizing the resource potential and minimizing the risk of rogue emissions. GP
- Hassanpouryouzband, A. et al., “An experimental investigation on the kinetics of integrated methane recovery and CO2 sequestration by injection of flue gas into permafrost methane hydrate reservoirs,” Scientific Reports, Vol. 9, November 7, 2019.
Corrosion Control for Gas Treating Amines: Technology Leads to Increased Amine Unit Efficiency
Accelerated basin drilling activities combined with increased fugitive gas emission capture technologies have increased trace oxygen levels in midstream natural gas. Oxygen present in concentrations even as low 30-50 ppm will cause costly corrosion-related problems in plant operations and processing equipment. One area in the plant most affected by oxygen is the amine unit. Oxygen will degrade MDEA-blended amines to corrosive amino acids and heat-stable amine salts.
Learn how a new technology from BASF combined with innovation from Nalco Water can increase amine efficiency and reduce costs associated with corrosion. This new technology will inhibit the degradation of amines from oxygen attack and control corrosion in process gas, while stabilizing the amine from degradation into bicine and other heat-stable amine salts. Together with Nalco Water’s real-time amine corrosion control program, have been proven to both mitigate oxygen degradation of amine and reduce the overall corrosivity of amine units.
August 19, 2020 10:00 AM CDT