Carbon Dioxide Capture And Sequestration Research Articles

Carbon dioxide hydrate crystallization thickening & morphology in a micro-confined environment for carbon capture & sequestration processes

Carbon dioxide capture and sequestration (CCS) are critical processes that are necessary to mitigate the impacts of climate change. In pipelines used for CCS and for ocean sequestration, the formation of CO2 hydrates can occur and be detrimental to the safety and integrity of the CCS equipment and process. Understanding the crystallization thickening behavior of CO2 hydrates is vital for understanding hydrate formation in CO2 pipelines and in other CCS applications, such as sequestration and CO2 capture or storage. In this study, a microfluidic chip reactor was used to crystalize and thicken CO2 hydrates at the channel walls. The morphology of the CO2 hydrates was visually analyzed and quantified using in situ Raman spectroscopy. Two hydrate layers were consistently observed. An annealed, dense layer of hydrate shared an interface with liquid water, while a porous hydrate layer shared an interface with CO2 gas. Capillary-like pore spaces could be observed in the porous layer, which confirms one proposed mechanism for hydrate film thickening. Subcooling (0.5–1.5 K), pressure (2.51, 3.10 MPa), and flow rate of CO2 (0.167, 1.67 mm3/s) were studied for their impact on the overall CO2 hydrate film thickness over time. Over the ranges of these chosen parameters, only CO2 flow rate was found to have a significant impact on the thickening of CO2 hydrates, and a higher flow rate led to thicker crystalline hydrate films. A first principles mass transfer model for hydrate film thickness was developed and applied to the measurement data collected for overall hydrate film thickness.

Directed evolution of Mesorhizobium loti carbonic anhydrase for carbon dioxide sequestration by MutaT7 and rational codon design

BackgroundDirected evolution plays a crucial role in accelerating genetic development to obtain superior enzyme variants with high tolerance and activity. Under nature evolution, Mesorhizobium loti carbonic anhydrase (MlCA) stands out as one of the fastest metalloenzymes involved in carbon dioxide capture and sequestration (CCS). However, challenge arises when expressing the recombinant MlCA which affects its total catalytic function. Therefore, we aim to evolve MlCA by enhancing protein production and elevate catalytic efficiency in genetically Escherichia coli. MethodsA growth-dependent CRISPRi-based high-throughput screening platform DEPEND-2.0 with down-regulating essential gene was established. The in vivo target-specific MutaT7 mutator was employed to evolve MlCA and screened the mutants using DEPEND-2.0 based on cell growth. Structure prediction was further applied to analyze the mutant while the degenerated or definitive codons were designed to investigate the codon influence on the mRNA and enzyme production. Significant findingThe DEPEND-2.0 system, utilizing chromosomal dCas9, effectively inhibited cell growth by targeting the promoter region with sgRNA which maintained a repression rate of 65.4% at 4 h using high-copy RSF plasmid. Structural prediction using Alphafold revealed that a mutation introduced by MutaT7 at P105S resulted in a 99% loss of intrinsic activity due to the disruption of hydrogen bonding. Furthermore, synonymous codon designs demonstrated that AT-rich codons at the 5’ terminus of a 30-bp sequence exhibited higher mRNA levels and improved recombinant protein expression. Finally, the MlCA variant with A-rich codons (i.e., MA) effectively facilitated CO2 biomineralization, displaying high durability with 72% residual activity after five repeated reactions, ultimately accumulating 193 mg of CaCO3.

Assessing possibilities for coal continuance in India under climate constraints

Rapid shift from traditional energy intensive pathways is required to pace-up economic growth before exhausting remaining carbon budget under 2 °C global stabilization target. Within this larger context, in this paper we have used AIM/End-use, a bottom-up, techno-economic model to analyze India's energy security and greenhouse gas (GHG) emissions from the year 2000 to 2050 with a focus on possibilities of coal continuance in India. Our analysis shows that by adopting advanced coal technologies and carbon dioxide capture and sequestration (CCS) options, up to 45% CO2 emission reduction can be achieved over business-as-usual scenario (BAU) by 2050. This is possible even when coal use would increase to nearly 2200 Mt in 2050 as against 870 Mt in 2017-18. Without CCS, coal use could peak at 1200 Mt with 22% CO2 reduction over BAU in 2050 but in that case nuclear and renewable energy would become pivotal in meeting energy demand. The paper concludes that a win-win integration of energy security and deep GHG emission mitigation is possible through a large-scale integration of advanced coal technologies and CCS in Indian energy systems. We have also provided a brief PESTLE analysis for finding the enabling environment necessary for achieving the results discussed in various scenarios.

Development of multimode gas-fired combined-cycle chemical-looping combustion-based power plant layouts.

Operation of power plants with carbon dioxide capture and sequestration (CCS) and without carbon dioxide capture and storage modes and energy penalty or energy utilization in such operations is of great significance. This work reports on two gas-fired pressurized chemical-looping combustion (CLC) power plant layouts with two inbuilt modes of flue gas exit, namely, one with carbon dioxide capture mode and the second mode is letting flue gas (consists of carbon dioxide and water) without capturing carbon dioxide. Without CCS mode, the higher thermal efficiencies of 54.06 and 52.63% are obtained for natural gas and syngas, respectively. In carbon capture mode, a net thermal efficiency of 52.13% is obtained with natural gas and 48.78% with syngas. The operating pressure of the air reactor is taken to be 13bar for realistic operational considerations, and that of the fuel reactor is 11.5bar. Two power plant layouts were developed based on combined-cycle chemical-looping combustion (CC CLC) for natural gas and syngas fuels. A single layout is developed for two fuels with a possible retrofit for dual fuel operation. The CLC power plants can be operated with two modes of flue gas exit options, and these operational options make them higher thermal efficient power plants.

Carbon Capture and Sequestration: An Overview

Abstract: Carbon dioxide capture and sequestration (CCS) is the capture and storage of carbon dioxide (CO2) that is emitted to the atmosphere as a result of combustion process. Presently majority of efforts focus on the removal of carbon dioxide directly from industrial plants and thereby storing it in geological reservoirs. The principle is to achieve a carbon neutral budget if not carbon negative, and thereby mitigate global climate change. Currently, fossil fuels are the predominant source of the global energy generation and the trend will continue for the rest of the century. Fossil fuels supply over 63% of all primary energy; the rest is contributed by nuclear, hydro-electricity and renewable energy. Although research and investments are being targeted to increase the percentage of renewable energy and foster conservation and efficiency improvements of fossil-fuel usage, development of CCS technology is the most important tool likely to play a pivotal role in addressing this crisis. [1] Keywords: Carbon Capture and Storage, Carbon dioxide, fossil fuels, Greenhouse gases

An experimental and modeling study on incipient hydrate-forming conditions for ternary guests of carbon dioxide, nitrogen and sulfur dioxide

In carbon dioxide capture and sequestration (CCS) processes, captured CO2 may encounter conditions of hydrate formation due to the presence of water. For stable, long-term operation of CCS processes, hydrate-phase equilibrium data are essential. Captured CO2 from combustion of fossil fuel may include other impurities such as N2 and SO2. Phase equilibria including a single impurity (N2 or SO2) have been reported by other researchers, but no experimental observations have been obtained for ternary guest systems. In this work, the incipient hydrate-forming temperatures for a binary guest of CO2 and N2 and a ternary guest of CO2, N2 and SO2 were experimentally measured at 2.0–3.5 MPa. An effect of the ratio between guest components and water was observed. The experimental results were compared with calculations using an equation of state based on a hydrogen-bonding nonrandom lattice fluid (NLF-HB) combined with the van der Waals-Platteeuw model. The model predictions were in good agreement with experimental data with an overall average deviation of 2.6%.

Enhancement of carbon dioxide capture by amine‐modified rice husk mesoporous material

Carbon dioxide capture and sequestration (CCS) has become a promising mitigation measure to reduce carbon dioxide (CO2) emissions from large stationary point sources. The CO2 capture process is the core limitation in terms of operating costs and energy consumption. To address this problem, this work aims to produce low cost solid sorbents for capturing CO2. Rice husk was used as a silica source for Mobil Composition of Matter No. 41 (MCM‐41) synthesis (called R‐MCM‐41). To enhance the CO2 adsorption performance at a high temperature, polyethyleneimine (PEI), monoethanolamine (MEA), and aniline (ANL) were applied as modification reagents onto the R‐MCM‐41 surface. The adsorption test was conducted by using an adsorption column. The results indicated that the adsorption capacity of R‐MCM‐41 decreased with an increase in adsorption temperature. However, amine modification can enhance the adsorption capacity at high adsorption temperatures. Out of all the materials tested, the R‐MCM‐41 impregnated with 50 wt % of PEI provided the highest adsorption capacity at 1.70 mmol g−1. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1716–1723, 2016

Shallow groundwater system monitoring on controlled CO2 release sites: a review on field experimental methods and efforts for CO2 leakage detection

Carbon dioxide capture and sequestration (CCS) is a promising alternative for reduction of greenhouse gas emission. However, injected CO2 in deep formation has potential to leak into a shallow aquifer. Thus, although it is challenging, development of detection technologies in a shallow aquifer region is essential to assure the long term safety of a CCS project. Recently, field scale experiments were carried out around the world to identify CO2 leakage and to investigate effects on groundwater quality in shallow aquifers. From the literature, 8 controlled CO2 release test sites and 9 experimental cases were identified. In those sites, CO2 was artificially injected around the shallow aquifer region as CO2-infused groundwater phase or gas phase for identifying environmental effects caused by CO2 injection. This paper reviews the hydraulic heterogeneity, mineral compositions, monitoring systems, and environmental parameters required for leakage detection at each site. For constructing a controlled test bed, inclined wells, horizontal wells, and multiple injection wells were identified as reliable injection components. It was also identified that the injected CO2 migration and its effects were monitored through the constructed monitoring networks. The previous operation cases show that continuous monitoring of pH, electrical conductivity (EC), Ca and Mg concentrations is the most basic and important factor for leakage detection. Trace elements and isotopes were also widely used to determine the CO2 leakage. The Korea CO2 Storage Environmental Management (K-COSEM) research center is going to construct an environmental impact test (EIT) facility for developing CO2 leakage detection methods in a shallow aquifer region in Korea. The challenging issues will include the fate and transport of CO2 from the fractured zone to the saturated zone and to the unsaturated soil. Based on the lessons learned from the previous tests, environmental monitoring technologies will be developed through the analysis of the time series data of hydrogeochemical parameters for the planned EIT facility in Korea.

A study on the effect of the amine structure in CO2 dry sorbents on CO2 capture

Carbon dioxide capture and sequestration (CCS) has received considerable attention as total energy dependency on fossil fuel continues to increase. One of the crucial technologies of CCS is the development of organic–inorganic hybrid dry sorbent for CO2 capture in adsorption processes. In this study, in situ polymerization and functionalization technology of aminosilane inside the pore of silica was employed to prepare a sorbent with enhanced characteristics. It was confirmed that the sorbent prepared through in situ polymerization of aminosilane inside the pore of SiO2 showed higher amine content and enhanced CO2 adsorption capacity than the sorbent prepared by conventional grafting method. Furthermore, the polyaminosilane functionalized sorbent was evaluated by in situ IR to examine the CO2 adsorption and desorption behaviors and species during the temperature swing process. The CO2-adsorbed species were found out to be silylpropylcarbamate, carbamic acid and carbamate. Though the similar adsorbed species were observed regardless of amine structure of the aminosilane incorporated, the desorption temperatures of the each adsorbed species were strongly affected by the amine structure. Consideration of these desorption behaviors can be beneficial in the selection of the desorption condition upon implementation of these sorbents in commercial capturing process.

Hydrate equilibrium data for the CO2 + N2 system with the use of tetra-n-butylammonium bromide (TBAB), cyclopentane (CP) and their mixture

Carbon Dioxide capture and sequestration (CCS) is nowadays an important area of research for decreasing CO2 emissions worldwide. Hydrates can become of great importance in the future as they form the basis for a new technology that can be used for CO2 capture from flue gases (hydrate crystallization). In this work hydrate equilibrium data are measured and compared with literature data. In particular, experimental results for hydrate dissociation with several promoters are presented. The isochoric method is used to determine the gas hydrate dissociation points. Different CO2 + N2 gas mixtures were used with presence of promoters such as tetra-n-butylammonium bromide (TBAB), cyclopentane (CP) and mixtures of TBAB with CP. The novelty of this work is the combination of promoters, TBAB and CP, which under certain conditions induced greater pressure reduction in comparison to pure TBAB results. Concerning experiments with pure promoters, there is excellent consistency between our results and literature results for different gas mixtures and promoter concentrations. Finally, experimental uncertainties for temperature, pressure, and molar composition are also presented.

Compressor selection methods for multi-stage re-liquefaction system of liquefied CO2 transport ship for CCS

Recently, CCS (carbon dioxide capture and sequestration) has been receiving considerable attention as a possible means of dealing with emissions of CO2, a greenhouse gas. To this end, EOR (enhanced oil recovery) and EGR (enhanced gas recovery) are regarded as being viable options for economically sequestrating large amounts of CO2. A feasible approach would involve capturing CO2 from large-scale CO2 emission sources such as power plants, and then transporting that captured gas to near-depleted oil and gas wells to maintain the reservoir pressure and enhance the oil/gas recovery rate. In the future, CO2 will be transported large distances from emission sources in developed countries to oil/gas producing regions by pipelines or ships. The long-distance ship-based transport of CO2 would require that the gas be compressed or liquefied (LCO2). Furthermore, an LCO2 transport ship would have to be capable of processing boil-off gas while at sea.In this study, the selection method of compressors for re-liquefaction system of dedicated LCO2 transport ship was investigated by computational method. The performance of same compression ratio (SCR) method exhibited low levels of efficiency and reliability as for coefficient of performance (COP) and compressor discharge temperature in terms of oil degradation compared to that of intermediate pressure optimization (IPO). Of these three methods, IPO produced the highest level of performance of all, but could not guarantee compressor reliability as like SCR, too. Intermediate pressure optimization with same discharge temperature (IPODT) method was found to be better in terms of reliability, with a decrease in performance of only 5% relative to that obtained by IPO. Consequently, we recommend the use of the IPODT method for the design of a multi-stage compression system for the re-liquefaction cycle of an LCO2 transport ship.

Heat Integration of Biomass Co-firing in Coal Power Plant

Carbon dioxide from combustion of fossil is the major source of greenhouse gas emissions, which has recently been vigorously regulated worldwide. Oxy-coal combustion with carbon dioxide capture and sequestration (CCS) is among the promising clean coal technologies for reduction of CO2 emission. However, the efficiency of an oxy-coal plant is significantly lower than that of air-combustion counterpart due to energy penalties from air separation and CO2 compressor units. Concerning CO2 emission, oxy-co-combustion with biomass induces the CO2 reduction. For comparisons purposes, the study also evaluates the combustion impact on coal blending with biomass. To compensate the energy loss, pressurized combustion and heat integration framework are introduced in a 100 MWe-scale power plant constructed by Aspen Plus in this study. The results demonstrate that more thermal energy is retrieved from high-density gas at elevated pressure by increasing the temperature of waste flue gas and reducing the amount of steam extracted from the turbines. With heat integration configuration, the heat source from coal combustion is completely utilized to achieve higher efficiency.

Research Progress of the Interfacial Tension in Supercritical CO2-water/oil System

Carbon dioxide (CO2) is considered as one of major greenhouse gases, which has a significant contribution to global warming and has attracted more and more attention in recent years. So it s necessary to develop more efficient technologies to reduce CO2 emission. Carbon dioxide capture and sequestration (CCS) is one promising option to reduce CO2. CO2 flooding technique can enhance the oil recovery and achieve the storage of CO2 simultaneously. Therefore it is an important technology to support common development in terms of energy and environment. Under the high pressure, the interfacial tension (IFT) can affect fluid flow during the process of CO2 flooding greatly. Accordingly, there is an important significance to research miscible slug process and improve displacement efficiency. Hence the study of the IFT on supercritical CO2-water/oil system is indispensable.In order to understand the characteristic of IFT in-depth, this paper summarizes the IFT of CO2-water/oil system from the aspect of measuring methods, influencing factors and theoretical models. Currently there are less experimental data of IFT under the high pressures because of measuring difficulties in supercritical CO2-water/oil system. As one of the most effective measurement methods, the pendant drop method is developed gradually. This paper introduces the fundamental principles of several methods including selected plane method (SP), drop shape analysis (DSA) and axisymmetric drop shape analysis (ADSA). The relationships between pressure, temperature, concentration of CO2, salinity and IFT are summarized. Generally speaking, the IFT increases with the increasing pressure and salinity, while decreases with the increasing molar fraction of CO2. The effect of temperature on IFT is controversial in different researches. At the same time, this paper also presents the theoretical models of IFT in supercritical CO2-water/oil system. The work shows clearly the basic principles and applicable scopes of the statistical thermodynamics theories including density gradient theory (DGT) and density function theory (DFT). Finally, the directions should be strengthened concerning the study of IFT as follows: In terms of experiment, it is necessary to find out a method to measure the practical density difference by tracing system; Besides, a more accurate equation of state (EOS) should be constructed to calculate IFT. Therefore the proper measurement method, accurate injection pressure and concentration of CO2, rigorous theory and reliable mathematical model can be considered as research directions in future works.

Numerical simulation and optimization of CO2 sequestration in saline aquifers

With heightened concerns on CO2 emissions from coal fired electricity generation plants, there has been major emphasis in recent years on the development of safe and economical Carbon Dioxide Capture and Sequestration (CCS) technology worldwide. Saline reservoirs are attractive geological sites for CO2 sequestration because of their huge capacity for long term sequestration. Over the last decade, numerical simulation codes have been developed in US, Europe and Japan to determine a priori the CO2 storage capacity of a saline aquifer and to provide risk assessment with reasonable confidence before the actual deployment of CO2 sequestration can proceed with enormous investment. In US, the 2nd version of Transport of Unsaturated Groundwater and Heat (TOUGH2) numerical simulator has been widely used for this purpose. However at present, it does not have the ability to determine optimal parameters such as injection rate, injection pressure, injection depth for vertical and horizontal wells, etc. for optimization of the CO2 storage capacity and for minimizing the leakage potential by confining the plume migration. This paper describes the development of a “Genetic Algorithm (GA)” based optimizer for TOUGH2 that can be used by the industry with good confidence to optimize the CO2 storage capacity in a saline aquifer of interest. This new code including the TOUGH2 and the GA optimizer is designated as “GATOUGH2”. It has been validated by conducting simulations of three widely used benchmark problems by the CCS researchers worldwide: (a) study of CO2 plume evolution and leakage through an abandoned well, (b) study of enhanced CH4 recovery in combination with CO2 storage in depleted gas reservoirs, and (c) study of CO2 injection into a heterogeneous geological formation. The results of these simulations are in excellent agreement with those of other researchers using different codes. The validated code has been employed to optimize the proposed water-alternating-gas (WAG) injection scheme for (a) a vertical CO2 injection well and (b) a horizontal CO2 injection well, in order to optimize the CO2 sequestration capacity of an aquifer. The optimized calculations from GATOUGH2 are compared with the brute force nearly optimized results obtained by performing a large number of calculations. These comparisons demonstrate the significant efficiency and accuracy of GATOUGH2 as an optimizer compared to using TOUGH2 in a brute force manner. This capability holds a great promise in studying a host of other problems in CO2 sequestration such as how to optimally accelerate the capillary trapping, accelerate the dissolution of CO2 in water or brine, and immobilize the CO2 plume.

CO2 capture and sequestration source-sink match optimization in Jing-Jin-Ji region of China

Carbon dioxide capture and sequestration (CCS) is considered to be an important option for climate change mitigation. A key problem for the implementation of CCS technology is the source-sink match design and optimization when considering both economic and environmental requirement. This paper presents a generic-optimization-based model for the strategic planning and design of future CCS source-sink matching. The features and capabilities of the model are illustrated through a detailed case study for the Jing-Jin-Ji (Beijing, Tianjin and Hebei Province) region in China. It shows how the model helps make a compromise in arriving at a strategic decision for CCS source-sink matching by providing the tradeoff frontiers between economic and environmental performance, and the features of match solutions with the best economic performance or with the best environmental performance.

CO2 Sequestration in Deep Sedimentary Formations

Carbon dioxide capture and sequestration (CCS) in deep geological formations has recently emerged as an important option for reducing greenhouse emissions. If CCS is implemented on the scale needed to make noticeable reductions in atmospheric CO2, a billion metric tons or more must be sequestered annually—a 250 fold increase over the amount sequestered today. Securing such a large volume will require a solid scientific foundation defining the coupled hydrologic-geochemical-geomechanical processes that govern the long-term fate of CO2 in the subsurface. Also needed are methods to characterize and select sequestration sites, subsurface engineering to optimize performance and cost, approaches to ensure safe operation, monitoring technology, remediation methods, regulatory overview, and an institutional approach for managing long-term liability.

A review of carbon dioxide capture and sequestration and the Kyoto Protocol’s clean development mechanism and prospects for Southern Africa

AbstractThe clean development mechanism (CDM) of the Kyoto Protocol is a financial incentive intended to make economically marginal greenhouse gas (GHG) prevention projects more feasible. Carbon dioxide capture and sequestration (CCS) is a possi-ble GHG mitigating strategy. The Intergovernmental Panel on Climate Change (IPCC) defines a CCS project as a process consisting of three phases: the separation of carbon dioxide from industrial and energy-related sources; transportation of the carbon dioxide to a storage location; and long-term isola-tion of the carbon dioxide from the atmosphere. This paper focuses on prospects of CCS as CDM projects in general and in the context of Southern Africa. Currently there is no evidence of a long term proven track record of integrated CCS systems; only three industrial scale CCS projects exist global-ly. Nevertheless, new concepts have been proposed for CCS CDM projects such as long-term liability and certified emission reduction (CER) cancellation. However, these concepts are not in the current CDM framework at present. It is thus difficult to prove CCS as an eligible CDM project without first addressing possible expansion and shortfalls of the current CDM structure. More research is also required to quantify the trade offs presented between mitigating carbon dioxide from the atmos-phere at the possible detriment of the areas of stor-age in the Southern Africa context. Only then may CCS projects be deemed more viable in the CDM context. Finally, although the potential for CCS in South Africa has been noted due to major point sources, the cost of capture and storage is a major obstacle; matching point sources and geological storage options is problematic for South Africa and neighbouring countries due to large transport dis-tances. The regulatory risks associated with CCS are further deterrents for the implementation of CCS CDM projects in Southern Africa in the near future.