Gas Recovery Through the Injection of Carbon Dioxide or Concentrated Flue Gas in a Natural Gas Hydrate Reservoir (original) (raw)
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Flue gas injection into gas hydrate reservoirs for methane recovery and carbon dioxide sequestration
Energy Conversion and Management, 2017
Flue gas injection into methane hydrate-bearing sediments was experimentally investigated to explore the potential both for methane recovery from gas hydrate reservoirs and for direct capture and sequestration of carbon dioxide from flue gas as carbon dioxide hydrate. A simulated flue gas from coal-fired power plants composed of 14.6 mole% carbon dioxide and 85.4 mole% nitrogen was injected into a silica sand pack containing different saturations of
Transport and storage of CO2 in natural gas hydrate reservoirs
Energy Procedia, 2009
Storage of CO 2 in natural gas hydrate reservoirs may offer stable long term deposition of a greenhouse gas while benefiting from methane production, without requiring heat. By exposing hydrate to a thermodynamically preferred hydrate former, CO 2 , the hydrate may be maintained macroscopically in the solid state and retain the stability of the formation. One of the concerns, however, is the flow capacity in such reservoirs. This in turn depends on three factors; 1) thermodynamic destabilization of hydrate in small pores due to capillary effects, 2) the presence of liquid channels separating the hydrate from the mineral surfaces and 3) the connectivity of gas-or liquid filled pores and channels. This paper reports experimental results of CH 4 -CO 2 exchange within sandstone pores and measurements of gas permeability during stages of hydrate growth in sandstone core plugs. Interactions between minerals and surrounding molecules are also discussed. The formation of methane hydrate in porous media was monitored and quantified with magnetic resonance imaging techniques (MRI). Hydrate growth pattern within the porous rock is discussed along with measurements of gas permeability at various hydrate saturations. Gas permeability was measured at steady state flow of methane through the hydrate-bearing core sample. Experiments on CO 2 injection in hydrate-bearing sediments was conducted in a similar fashion. By use of MRI and an experimental system designed for precise and stabile pressure and temperature controls flow of methane and CO 2 through the sandstone core proved to be possible for hydrate saturations exceeding 60 %.
This paper focuses on methane recovery from gas hydrates and the thermal assisted CH4-CO2 replacement in the hydrate phase. The experimental investigation was carried out in a 60 L reactor, in which the CH4 hydrates were formed with different saturations of the matrix (10%, 30% and 50%) and subsequently dissociated by supplying heat and a simultaneous CO2 stream. The tests simulated the down-hole combustion method for gas production in hydrate reservoirs and the CO2 injection was purposefully set to match the output from the combustion system operating on liquid fuel. CH4-CO2 replacement was studied both via CO2 flow-through experiments and baseline thermal dissociation experiments utilizing heating rates from 50 watts to 100 watts. In presence of low hydrate saturation levels, with the 50 W heating rate, the CH4-CO2 exchange and CO2 sequestration occurs within the first hours of the tests, while a 100 W heating rate resulted in a considerable reduction of favourable regions for CO2 capture. Tests at higher hydrate saturation levels, with a 100 W heating rate, show that the addition of CO2 increased the number of moles of CH4 recovered and reduced the length of the test. At higher saturations, the hydrate dissociation process gives an adequate thermostatic effect to counterbalance the higher heating power, and maintain temperatures under the CO2 hydrate equilibrium line. Finally, for a 50 W heating rate, carbon balance calculations, in which the CO2 entrapped in the hydrate phase and the CO2 produced during the thermal stimulation process and the combustion of the released CH4, resulted in a substantially negative carbon footprint of the CH4 extraction-CO2 injection process, proving its sustainability.
Marine and Petroleum Geology, 2011
Class 1 gas hydrate accumulations are characterized by a permeable hydrate-bearing interval overlying a permeable interval with mobile gas, sandwiched between two impermeable intervals. Depressurization-induced dissociation is currently the favored technology for producing gas from Class 1 gas hydrate accumulations. The depressurization production technology requires heat transfer from the surrounding environment to sustain dissociation as the temperature drops toward the hydrate equilibrium point and leaves the reservoir void of gas hydrate. Production of gas hydrate accumulations by exchanging carbon dioxide with methane in the clathrate structure has been demonstrated in laboratory experiments and proposed as a field-scale technology. The carbon dioxide exchange technology has the potential for yielding higher production rates and mechanically stabilizing the reservoir by maintaining hydrate saturations. We used numerical simulation to investigate the advantages and disadvantages of using carbon dioxide injection to enhance the production of methane from Class 1 gas hydrate accumulations. Numerical simulations in this study were primarily concerned with the mechanisms and approaches of carbon dioxide injection to investigate whether methane production could be enhanced through this approach. To avoid excessive simulation execution times, a five-spot well pattern with a 500-m well spacing was approximated using a two-dimensional domain having well boundaries on the vertical sides and impermeable boundaries on the horizontal sides. Impermeable over-and under burden were included to account for heat transfer into the production interval. Simulation results indicate that low injection pressures can be used to reduce secondary hydrate formation and that direct contact of injected carbon dioxide with the methane hydrate present in the formation is limited due to bypass through the higher permeability gas zone.
Elsevier, 2019
• Inclusion of 15% N 2 in CO 2 stream increases CH 4 recovery by at least 25%. • CH 4 is first replaced by CO 2 in large cages followed by N 2 in small cages. • N 2 is selectively captured in hydrate cages below 12 °C. • Higher sequestration potential observed at lower heating rates. A B S T R A C T Thermal stimulation was combined with an injection of a mixture of CO 2 (85%) + N 2 (15%) to investigate efficiency enhancements from pure thermal stimulation and thermal stimulation with CO 2 injection approaches. Tests were performed at initial hydrate saturation of 10% and 300 ml/min CO 2 + N 2 injection rate with three different heating rates of 20, 50 and 100 W. The results indicate that thermal stimulation with CO 2 + N 2 injection is the most efficient method available for methane gas recovery. At 10% Hydrate Saturation (SH) and 100 W heating rate, the number of moles of CH 4 recovered increased from 8.5 to 16 to 20 in the case of thermal stimulation, thermal stimulation with CO 2 exchange and thermal stimulation with CO 2 + N 2 exchange respectively. The experimental results reported here are aligned with model and Raman spectroscopy predictions in terms of replacement mechanism and recovery efficiency, reported in the literature. The results obtained from CO 2 /N 2 composition ratio show that in the exchange process, CO 2 first replaces CH 4 in the large cages of Structure I hydrates followed by N 2 targeting CH 4 in the small cages of Structure I hydrates. This replacement mechanism has been predicted in the literature by Liu et al. (2016) using Molecular Dynamics simulations. It is also found from this work that N 2 is selectively captured in hydrate cages below 12 °C. The values of carbon sequestration index (defined as moles of CO 2 sequestered divided by moles of CH 4 recovered) were 0.32, 0.52 and 0.85 respectively for 100, 50 and 20 W heating tests. The data obtained from our work in terms of gas composition, methane recovery and CO 2 sequestered is consistent with the key findings reported in the literature .
Scientific Reports
Large hydrate reservoirs in the Arctic regions could provide great potentials for recovery of methane and geological storage of CO2. In this study, injection of flue gas into permafrost gas hydrates reservoirs has been studied in order to evaluate its use in energy recovery and CO2 sequestration based on the premise that it could significantly lower costs relative to other technologies available today. We have carried out a series of real-time scale experiments under realistic conditions at temperatures between 261.2 and 284.2 K and at optimum pressures defined in our previous work, in order to characterize the kinetics of the process and evaluate efficiency. Results show that the kinetics of methane release from methane hydrate and CO2 extracted from flue gas strongly depend on hydrate reservoir temperatures. The experiment at 261.2 K yielded a capture of 81.9% CO2 present in the injected flue gas, and an increase in the CH4 concentration in the gas phase up to 60.7 mol%, 93.3 mol%...
Thermally Assisted Dissociation of Methane Hydrates and the Impact of CO2 Injection
The largest amount of methane gas is trapped in lessconventional natural gas resources, such as methane hydrates. It is estimated that these reserves of methane gas, in the form of hydrates, are larger than all of the conventional resources of methane gas combined. [U.S. Energy Information Administration (EIA), Independent Statistics and Analysis, Potential of Gas Hydrates Is Great, but Practical Development Is Far of, http://www.eia.gov/todayinenergy/detail.cfm?id=8690\]. Methane extraction from hydrates can be coupled with carbon dioxide sequestration to make this process carbon-neutral. A large-scale laboratory reactor is used to simulate the conditions existing in permafrost hydrate sediments to study the hydrate formation and dissociation processes. The dissociation process occurs via a cartridge heat source (to simulate the down-hole combustion) and carbon dioxide injection, to study the CO2 sequestration behavior. The hydrate sediment studied was formed with 50% saturation of hydrate by pore volume and the dissociation of this sediment was done using different combinations of high and low heating rates (100 W and 20 W) and high and low CO2 injection rates (1000 and 155 mL/min). Two baseline tests were conducted without any addition of heat at CO2 injection rates of 155 and 1000 mL/min, for comparison. The results indicate that, at a constant heating rate, the number of moles of methane recovered decreases with an increasing flow rate of CO2 injection, whereas the number of moles of CO2 sequestered increases as the CO2 injection flow rate increases. At 50% initial hydrate saturation (SH) and a heating rate of 100 W, the number of moles of methane recovered decreased from 96 to 58 when the CO2 injection rate was increased from 155 mL/ min to 1000 mL/min, respectively. Whereas, at 50% initial saturation and a heating rate of 100 W, the number of moles of CO2 sequestered increased from 13 to 40 when the CO2 injection rates were increased from 155 mL/min to 1000 mL/min. The recovery efficiency improved from 18% to 22% to 60% when the heating rate was increased from 0 to 20 W to 100 W, respectively, at 1000 mL/min CO2 injection.
A Review on CO2 Capture Technologies with Focus on CO2-Enhanced Methane Recovery from Hydrates
Energies
Natural gas is considered a helpful transition fuel in order to reduce the greenhouse gas emissions of other conventional power plants burning coal or liquid fossil fuels. Natural Gas Hydrates (NGHs) constitute the largest reservoir of natural gas in the world. Methane contained within the crystalline structure can be replaced by carbon dioxide to enhance gas recovery from hydrates. This technical review presents a techno-economic analysis of the full pathway, which begins with the capture of CO2 from power and process industries and ends with its transportation to a geological sequestration site consisting of clathrate hydrates. Since extracted methane is still rich in CO2, on-site separation is required. Focus is thus placed on membrane-based gas separation technologies widely used for gas purification and CO2 removal from raw natural gas and exhaust gas. Nevertheless, the other carbon capture processes (i.e., oxy-fuel combustion, pre-combustion and post-combustion) are briefly di...