Carbon Dioxide Sequestration Methodothologies—A Review

The process of capturing and storing carbon dioxide (CCS) was previously considered a crucial and time-sensitive approach for diminishing CO2 emissions originating from coal, oil, and gas sectors. Its implementation was seen necessary to address the detrimental effects of CO2 on the atmosphere and the ecosystem. This recognition was achieved by previous substantial study efforts. The carbon capture and storage (CCS) cycle concludes with the final stage of CO2 storage. This stage involves primarily the adsorption of CO2 in the ocean and the injection of CO2 into subsurface reservoir formations. Additionally, the process of CO2 reactivity with minerals in the reservoir formations leads to the formation of limestone through injectivities. Carbon capture and storage (CCS) is the final phase in the CCS cycle, mostly achieved by the use of marine and underground geological sequestration methods, along with mineral carbonation techniques. The introduction of supercritical CO2 into geological formations has the potential to alter the prevailing physical and chemical characteristics of the subsurface environment. This process can lead to modifications in the pore fluid pressure, temperature conditions, chemical reactivity, and stress distribution within the reservoir rock. The objective of this study is to enhance our existing understanding of CO2 injection and storage systems, with a specific focus on CO2 storage techniques and the associated issues faced during their implementation. Additionally, this research examines strategies for mitigating important uncertainties in carbon capture and storage (CCS) practises. Carbon capture and storage (CCS) facilities can be considered as integrated systems. However, in scientific research, these storage systems are often divided based on the physical and spatial scales relevant to the investigations. Utilising the chosen system as a boundary condition is a highly effective method for segregating the physics in a diverse range of physical applications. Regrettably, the used separation technique fails to effectively depict the behaviour of the broader significant system in the context of water and gas movement within porous media. The limited efficacy of the technique in capturing the behaviour of the broader relevant system can be attributed to the intricate nature of geological subsurface systems. As a result, various carbon capture and storage (CCS) technologies have emerged, each with distinct applications, associated prices, and social and environmental implications. The results of this study have the potential to enhance comprehension regarding the selection of an appropriate carbon capture and storage (CCS) application method. Moreover, these findings can contribute to the optimisation of greenhouse gas emissions and their associated environmental consequences. By promoting process sustainability, this research can address critical challenges related to global climate change, which are currently of utmost importance to humanity. Despite the significant advancements in this technology over the past decade, various concerns and ambiguities have been highlighted. Considerable emphasis was placed on the fundamental discoveries made in practical programmes related to the storage of CO2 thus far. The study has provided evidence that despite the extensive research and implementation of several CCS technologies thus far, the process of selecting an appropriate and widely accepted CCS technology remains challenging due to considerations related to its technological feasibility, economic viability, and societal and environmental acceptance.

Recovering methane from quartz sand-bearing hydrate with gaseous CO2

The replacement method by CO_2 is regarded as a new approach to natural gas hydrate(NGH) exploitation method, by which methane production and carbon dioxide sequestration might be obtained simultaneously. In this study, CO_2 was used to recover CH_4 from hydrate reservoirs at different temperatures and pressures. During the CO_2–CH_4 recovery process, the pressure was selected from 2.1 to 3.4 MPa, and the temperature ranged from 274.2 to 281.2 K. Calculating the fugacity differences between the gas phase and the hydrate phase for CO_2 and CH_4 at different conditions, it has found rising pressure was positive for hydrates formation process that was helpful for the improvement of CH_4 recovery rate. Rising temperature promoted the trend of CH_4 hydrate decomposition for the whole process of CO_2–CH_4replacement.The highest recovery rate was 46.6 % at 3.4 MPa 281.2 K for CO_2–CH_4replacement reaction in this work.

Effects of CO2-water interaction with coal on mineral content and pore characteristics

There are a large number of abandoned coalmines in China,and most of them are located around major coal-fired power stations,which are the largest emission sources of carbon dioxide(CO2).Considering the injection of CO2 into abandoned coalmines,which are usually in the flooded condition,it is necessary to investigate the effect of CO2-water-coal interaction on minerals and pore structures at different pressures,temperatures and times.It reveals that the CO2-water-coal interaction can significantly improve the solubility of Ca,S,Mg,K,Si,Al,Fe and Na.By comparing the mineral content and pore structure before and after CO2-water-coal interaction,quartz and kaolinite were found to be the main secondary minerals,which increased in all samples.The structures of micropores and mesopores in the range of 1.5-8 nm were changed obviously.Specific surface areas and pore volumes first increased and then decreased with pressure and time,while both increased with temperature.By using the Frenkel-Halsey-Hill model,the fractal dimensions of all samples were analyzed based on D(s1)and D(s2),which reflected the co mplexities of the pore surface and pore volume,respectively.The re sults show that fractal dimensions had very weak positive correlations with the carbon content.D(s1)had a positive correlation with the quartz and kaolinite contents,while D(s2)had a negative correlation with the quartz and kaolinite contents.

Indirect mineral carbonation of blast furnace slag with(NH4)2SO4 as a recyclable extractant

Large quantities of CO_2 and blast furnace slag are discharged in the iron and steel industry. Mineral carbonation of blast furnace slag can offer substantial CO_2 emission reduction and comprehensive utilisation of the solid waste. In this study, a recyclable extractant,(NH_4)_2SO_4, was used to extract calcium and magnesium from blast furnace slag(main phases of gehlenite and akermanite) by using low-temperature roasting to fix CO_2 through aqueous carbonation. The process parameters and efficiency of the roasting extraction, mineralisation, and Al recovery were investigated in detail. The results showed that the extractions of Ca, Mg, and Al can reach almost 100% at an(NH4)_2SO_4-to-slag mass ratio of 3:1 and at 370°C in 1 h. Adjusting the p H value of the leaching solution of the roasted slag to 5.5 with the NH_3 released during the roasting resulted in 99% Al precipitation, while co-precipitation of Mg was lower than 2%. The Mg-rich leachate after the depletion of Al and the leaching residue(main phases of CaSO_4 and SiO_2) were carbonated using(NH_4)_2CO_3 and NH_4HCO_3 solutions, respectively, under mild conditions. Approximately 99% of Ca and 89% of Mg in the blast furnace slag were converted into CaCO_3 and(NH_4)_2 Mg(CO_3)_2·4 H_2O,respectively. The latter can be selectively decomposed to magnesium carbonate at 100-200 °C to recover the NH_3 for reuse. In the present route, the total CO_2 sequestration capacity per tonne of blast furnace slag reached up to 316 kg, and 313 kg of Al-rich precipitate, 1000 kg of carbonated product containing CaCO_3 and SiO_2, and 304 kg of carbonated product containing calcium carbonate and magnesium carbonate were recovered simultaneously. These products can be used, respectively, as raw materials for the production of electrolytic aluminium, cement, and light magnesium carbonate to replace natural resources.

Will the future of shale reservoirs lie in CO2 geological sequestration?

CO2 geological sequestration in a depleted shale gas reservoir is a promising method to address the global energy crisis as well as to reduce greenhouse gas emissions. Though improvements have been achieved by many researchers, the carbon sequestration and enhanced gas recovery(CS-EGR) in shale formations is still in a preliminary stage. The current research status of CO2 sequestration in shale gas reservoirs with potential EGR is systematically and critically addressed in the paper. In addition, some original findings are also presented in this paper. This paper will shed light on the technology development that addresses the dual problem of energy crisis and environmental degradation.

Influence of SO_2 in incineration flue gas on the sequestration of CO_2 by municipal solid waste incinerator fly ash

The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator(MSWI) fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas.The reaction between fly ash and 100% CO2 was relatively fast;the uptake of CO2 reached 87g CO2/kg ash,and the sequestered CO2 could be entirely released at high temperatures.When CO2 content was reduced to 12%,the reaction rate decreased;the uptake fell to 41g CO2/kg ash,and 70.7% of the sequestered CO2 could be released.With 12% CO2 in the presence of SO2,the reaction rate significantly decreased;the uptake was just 17g CO2/kg ash,and only 52.9% of the sequestered CO2 could be released.SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.

Lattice Boltzmann Simulation of CO_2 Transport in Kerogen Nanopores——An Evaluation of CO_2 Sequestration in Organic-Rich Shales

Organic-rich shale resources remain an important source of hydrocarbons considering their substantial contribution to crude oil and natural gas production around the world. Moreover, as part of mitigating the greenhouse gas effects due to the emissions of carbon dioxide(CO_2) gas, organic-rich shales are considered a possible alternate geologic storage. This is due to the adsorptive properties of organic kerogen and clay minerals within the shale matrix. Therefore, this research looks at evaluating the sequestration potential of carbon dioxide(CO_2) gas in kerogen nanopores with the use of the lattice Boltzmann method under varying experimental pressures and different pore sizes. Gas flow in micro/nano pores differ in hydrodynamics due to the dominant pore wall effects, as the mean free path(λ) of the gas molecules become comparable to the characteristic length(H) of the pores. In so doing, the traditional computational methods break down beyond the continuum region, and the lattice Boltzmann method(LBM) is employed. The lattice Boltzmann method is a mesoscopic numerical method for fluid system, where a unit of gas particles is assigned a discrete distribution function(f). The particles stream along defined lattice links and collide locally at the lattice sites to conserve mass and momentum. The effects of gas-wall collisions(Knudsen layer effects) is incorporated into the LBM through an effective-relaxationtime model, and the discontinuous velocity at the pore walls is resolved with a slip boundary condition. Above all, the time lag(slip effect) created by CO_2 gas molecules due to adsorption and desorption over a time period, and the surface diffusion as a result of the adsorption-gradient are captured by an adsorption isotherm and included in our LBM. Implementing the Langmuir adsorption isotherm at the pore walls for both CO_2 gas revealed the underlying flow mechanism for CO_2 gas in a typical kerogen nano-pore is dominated by the slip flow regime. Increasing the equilibrium pressure, increases the mass flux due to adsorption. On the other hand, an increase in the nano-pore size caused further increase in the mass flux due to free gas and that due to adsorbed gas. Thus, in the kerogen nano-pores, CO_2 gas molecules are more adsorptive indicating a possible multi-layer adsorption. Therefore, this study not only provides a clear understanding of the underlying flow mechanism of CO_2 in kerogen nano-pores, but also provides a potential alternative means to mitigate the greenhouse gas effect(GHG) by sequestering CO_2 in organic-rich shales.

Technical and economic feasibility study of flue gas injection in an Iranian oil field

Nowadays,the non-hydrocarbon gases are the main sources for gas injection projects in different countries.The main advantages of the flue gas injection are low cost,readily available sources(which consists mainly of N2 and CO2)and low compressibility in comparison with other gases like CO2 or CH4(for a given volume at the same conditions).In addition,it occupies more space in the reservoir and it is an appropriate way for CO2 sequestering and consequently reducing greenhouse gases.In the aforementioned method,N2 and/or CO2 is injected into the oil reservoir for miscible and/or immiscible displacement of remaining oil.Moreover,a key parameter in the designing of a gas injection project is the minimum miscibility pressure(MMP)which is commonly calculated by running simulation case or implementing conventional correlations.From technical viewpoints,the lower MMP values are more flavor for miscible gas injection process due to lower injection pressure and consequently lower maintenance and lower injection costs.The main aim of this research is to investigate various gas injection methods(N2,CO2,produced reservoir gas,and flue gas)in one of the northern Persian gulf oil fields by a numerical simulation method.Moreover,for each scenario of gas injection technical and economical considerations are took into account.Finally,an economic analysis is implemented to compare the net present value(NPV)of the different gas injection scenarios in the aforementioned oil field.