Impure CO2 Research Articles

Straightforward synthesis of functionalized γ-Lactams using impure CO2 stream as the carbon source

Direct utilization of CO2 into organic synthesis finds enormous applications to synthesize pharmaceuticals and fine chemicals. However, pure CO2 gas is essential to achieve these transformations, and the purification of CO2 is highly cost and energy intensive. Considering this, we describe a straightforward synthetic route for the synthesis of γ-lactams, a pivotal core structure of bioactive molecules, by using commercially available starting materials (alkenes and amines) and impure CO2 stream (exhaust gas is collected from the car) as the carbon source. This blueprint features a broad scope, excellent functional group compatibility and application to the late-stage transformation of existing pharmaceuticals and natural products to synthesize functionalized γ-lactams. We believe that our strategy will provide direct access to γ-lactams in a very sustainable way and will also enhance the Carbon Capture and Utilization (CCU) strategy.

Electrocatalytic Upgrade of Impure CO2 by In Situ-Reconstructed Cu Catalysts with Gas Exsolution Electrolyzers

Electrocatalytic Upgrade of Impure CO₂ by In Situ-Reconstructed Cu Catalysts with Gas Exsolution Electrolyzers

Integrated Formation Evaluation for Site-Specific Evaluation, Optimization, and Permitting of Carbon Storage Projects

Participation in over 80 carbon capture and sequestration (CCS) projects spanning 25 years has led to the evolution of a recommended well-based appraisal workflow for CO2 sequestration in saline aquifers. Interpretation methods are expressly adapted for CCS applications to resolve key reservoir parameters, constrain field-scale modeling, provide answers required for the permitting process, and de-risk unique CCS evaluation challenges, such as Storage capacity Injectivity Containment. A challenge complicating all of the above is the eventual impact of three-way interaction among rock matrix, brine, and (impure) CO2 streams. Most logging, sampling, and laboratory techniques are adapted from established domains such as enhanced oil recovery, underground gas storage, and unconventional reservoir evaluation, though some CCS-specific innovation is also needed. Storage evaluation begins with established methods for lithology, porosity, permeability, and pressure, while special core analysis (SCAL) determines CO2 storage efficiency and relative permeability. Containment evaluation spans multiple disciplines and methods: the petrophysicist’s task to quantify seal capacity relies heavily on laboratory analysis, while geologists leverage downhole imaging tools to verify caprock structural/tectonic integrity. Geomechanics engineers define safe injection pressure via mechanical earth models (MEMs) built on advanced acoustic logs calibrated by core geomechanics, wellbore failure observations, and in-situ stress tests. The impact of rock-brine-CO2 interactions is studied via custom SCAL experiments and/or pore-scale digital rock simulations that rigorously represent chemical and thermal processes. Wireline formation tester samples provide representative formation brine as feedstock for SCAL. Water samples also enable operators to prove injection within regulatory limits while establishing baselines for future monitoring programs. Examples applied to recent CCS projects in North America are presented. All of the above data need to be integrated into a CCS model predicting the CO2 plume behavior across the area of interest and within multiple horizons.

Impure CO2 storage reactions of sandstone, mudstone and carbonate cemented cores: Experimental CO2 SO2 NOX O2 reaction metal mobilisation and fate

CO2 geological storage can be part of the solution to reduce carbon emissions to the atmosphere. An understanding of the geochemical processes occurring during CO2 storage is needed to reduce risk. Drill cores from a low salinity reservoir site proposed for CO2 storage, and the overlying and underlying formations, were characterised for minerals by QEMSCAN, total metals and porosity. Elements including Li, Ba, Sr, K, Mg, V, Zn, REE, Fe, Pb, P, and S were relatively elevated in the Moolayember Formation underlying the reservoir. Synchrotron XFM showed the main host of Mn was siderite, with Rb in K-feldspar, Zn and Cu in sphalerite and chalcopyrite, and As in pyrite in coal pores associated with coal laminations. Drill cores are reacted at reservoir conditions with synthetic formation water and an impure CO2 stream composition of CO2-SOx-NOx-O2 expected to be injected at the site. Elements released were dependant on mineral content, with quartz rich reservoir, lower Precipice Sandstone core reactions resulting in dissolution of trace carbonates, alteration of sulphides and monazite, and variable elevated dissolved Pb, and U. Dissolved Co, Ni, Ca, Zn, Li, Rb, and U were released at relatively elevated concentrations from the mudstone. For carbonate cemented upper Precipice Sandstone or Moolayember Formation core strong dissolution of calcite and ankerite, with corrosion of siderite, Fe-rich chlorite, and sulphides or monazite were observed after reaction. Dissolved elements including Ca, Mg, Mn, Sr, and Ba increased in experiments from the reaction of calcite, siderite, and ankerite. Generally dissolved Fe, Pb, Cr, Cu, Co etc. increased from dissolution, and subsequently decreased in concentration with adsorption and precipitation processes. The fast mobilisation of elements including Fe and Pb are consistent with the release of metals from carbonate dissolution and desorption. The presence of O2 and NOX in the gas stream results in Fe-(oxyhydr)oxide precipitation especially where Fe has been rapidly mobilised from dissolution of siderite and Fe-chlorite. This acts as a sink for Fe and provides new adsorption sites for sequestering a proportion of the trace metals. These processes are applicable to other CO2 storage sites and potential leakage indicators in overlying drinking water aquifers. The findings are also more broadly applicable to subsurface energy storage such as compressed air renewable energy storage, CO2 enhanced recovery, geothermal, natural gas or hydrogen storage.

Effect of H2O Content on the Corrosion Behavior of X52 Steel in Supercritical CO2 Streams Containing O2, H2S, SO2 and NO2 Impurities

In this study, the corrosion behavior of X52 pipeline steel affected by H2O content in supercritical CO2 streams containing O2, H2S, SO2 and NO2 impurities was investigated by the weight loss test and surface characterization. The corrosion differences of the steel in impure supercritical CO2 streams containing different H2O contents were analyzed. The influence of the variation of H2O content on the corrosion mechanism of steel in the complex impurity-containing supercritical CO2 streams was discussed. The results show that the H2O content limit is 100 ppmv in supercritical CO2 streams containing 200 ppmv O2, 200 ppmv H2S, 200 ppmv SO2 and 200 ppmv NO2 at 10 MPa and 50 °C. The impurities and their interactions significantly promote the formation of corrosive aqueous phase, thereby exacerbating the corrosion of X52 steel. The corrosion process of X52 steel in the environment with a low H2O content is controlled by the products of impurity reactions, whereas the impurities and the products of impurity reactions jointly control the corrosion process of the steel in the environment with a high H2O content.

Dehydration requirements for CO2 and impure CO2 for ship transport

CCS is expected to become an important contribution to the mitigation of carbon dioxide emissions. Transportation of CO2 from the capture site to the permanent storage reservoir plays a key role, and transportation by ship is now viewed as a relevant alternative for certain combinations of captured CO2 volume and distance.This paper presents experimental equipment, methods and new results for the water content of carbon dioxide and impure carbon dioxide in equilibrium with hydrates at temperatures between (-55 and -10)°C and pressures between (3 and 120) bar, hence in both vapour and liquid phases. The experimental data are compared with predictions from two thermodynamic models: the Cubic-Plus-Association equation of state and an approach using Multi-Fluid Helmholtz Energy Approximation (MFHEA) equations of state (EoS). In all cases, the hydrate-forming conditions are modelled by the solid solution theory of van der Waals and Platteeuw.

Influence of impurities on reactive transport of CO2 during geo-sequestration in saline aquifers

Carbon capture and storage (CCS) is a promising technology to reduce greenhouse gas emissions by storing CO2 in geological formations. Storing less pure CO2, which has low percentages of impurities, can reduce the cost of the process. However, impurities can affect the dynamics of CO2 propagation and its trapping mechanisms in porous media, potentially impacting the overall effectiveness of the storage process. Therefore, this study investigates the effect of impurities on the reactive transport of CO2 during geo-sequestration in a saline aquifer using a reliable reactive transport model. The effect of co-injected H2S and CH4 in the CO2 stream on CO2 plume migration, CO2 trapping mechanisms, minerals dissolution and precipitation, and cap rock integrity, was studied here. To do so, reactive transport modeling was performed using a compositional simulator based on actual data from Sleipner storage site. The model was run for pure CO2 and mixtures (CO2 with 5 wt% H2S and CO2 with 5 wt% CH4). The results showed that the impurities co-injected with CO2 affect the CO2 plume migration in the aquifer. For instance, injecting the CO2-CH4 mixture increased the CO2 horizontal migration below the cap rock compared to the pure CO2 injection case. However, the buoyancy effect of the injected gas was slightly reduced by adding H2S to the CO2 stream. The impurities influenced the pH of the system, and hence minerals dissolution and precipitation, and cap rock porosity changes. The impurities (CH4 and H2S) injected with CO2 were found to suppress an anticipated increase in the cap rock porosity and accelerated the mineral trapping of CO2 compared to pure CO2 storage. While, among the studied cases, the CO2-CH4 mixture case had the highest structural trapping and the lowest solubility trapping of CO2. Thus, this study suggests that storage of impure CO2 can enhance mineral trapping, maintain cap rock sealing, and change CO2 distribution in porous media while reducing separation costs.

Exploring the potential of nanosized oxides of zinc and tin as recyclable catalytic components for the synthesis of cyclic organic carbonates under atmospheric CO2 pressure

Nanomaterials based on tin (IV) oxide (SnO2) and zinc oxide (ZnO) were investigated in the search for active, environmentally benign, and inexpensive materials for the crucial reaction of CO2 cycloaddition to epoxides to afford cyclic carbonates. In particular, nanoparticles (NPs), nanorods (NRs), nanosheets (NSs) and microplates (µPLs) were prepared and used in combination with small amounts of TBAI (tetrabutylammonium iodide) as the nucleophile. Different from the general case of metal oxides, often requiring harsh reaction conditions, the most active compound in this study, SnO2-NPs, served as an active material for the cycloaddition of CO2 to several terminal epoxides under atmospheric pressure at moderate temperatures (60–80 °C) and could also be employed for converting internal epoxides under harsher conditions. Importantly, SnO2-NPs could also be used in the presence of impure CO2 feeds (20% methane in CO2) resembling low calorific landfill gas and could be recycled and reused. Overall, SnO2-NPs represent a promising, readily available, and inexpensive metal oxide-based material to produce cyclic carbonates under atmospheric CO2 pressure.

Numerical Simulation of Carbon Dioxide–Nitrogen Mixture Dissolution in Water-Saturated Porous Media: Considering Cross-Diffusion Effects

The possibility of impure carbon dioxide (CO2) sequestration can reduce the cost of these projects and facilitate their widespread adoption. Despite this, there are a limited number of studies that address impure CO2 sequestration aspects. In this study, we examine the convection–diffusion process of the CO2–nitrogen (N2) mixture dissolution in water-saturated porous media through numerical simulations. Cross-diffusion values, as the missing parameters in previous studies, are considered here to see the impact of N2 impurity on dissolution trapping in more realistic conditions. Homogeneous porous media are used to examine this impact without side effects from the heterogeneity, and then simulations are extended to heterogeneous porous media, which are a good representative of the real fields. Heterogeneity in the permeability field is generated with sequential Gaussian simulation. Using the averaged dissolved CO2 and dissolution fluxes for each case, we could determine the onset of different dissolution regimes and behaviors of dissolution fluxes in CO2–N2 mixture dissolution processes. The results show that there is a notable difference between the pure cases and impure cases. Additionally, a failure to recognize the changes in the diffusion matrix and cross-diffusion effects can result in significant errors in the dissolution process. At lower temperatures, the N2 impurity decreases the amount and flux of CO2 dissolution; however, at higher temperatures, sequestrating the CO2–N2 mixture would be a more reasonable choice due to enhancing the dissolution behavior and lowering the project costs. The results of the heterogeneous cases indicate that heterogeneity, in most cases, reduces the averaged dissolved CO2, and dissolution flux and impedes the onset of convection. We believe that the results of this study set a basis for future studies regarding the CO2–N2 mixture sequestration in saline aquifers.

Experimental study of impurity effects on convective mixing in Hele-Shaw cell with application to CO2 geological sequestration

Density-driven convective mixing, i.e., convective fingering, has been identified to enhance CO2 dissolution trapping in deep saline aquifers. In this study, a series of experiments in Hele-Shaw cells were conducted, and the effects of common impurities (N2, O2, and/or Ar) on the occurrence and development of the convective mixing process were compared and analyzed. It is demonstrated that the existence of these impurities, whether single or their mixture, delayed the onset of convection. However, the subsequent fingering development, including the mixing length and fingering footprint, exhibited different patterns and trends depending on the species and compositions of the impurities. The development and growth of the convective fingers displayed non-monotonic characteristics as a function of the concentration of single impurity Ar. Furthermore, the multiple impurities containing Ar had the potential to enhance the fingering development, especially during the advanced stage. Other than these cases involving Ar, the inclusion of other impurities (N2, and/or O2) was found to weaken the fingering development compared with the pure CO2 case. Nevertheless, the results of dissolved CO2 inventory suggested that the effects of different impurities at the same content, both single and multiple, might be similar to each other in the long term, except for the three-impurity case involving Ar. The laboratory experiments in the present study can help establishing a better understanding of the effects of multiple impurities in the application of impure CO2 geological sequestration.

Direct electrochemical CO2 conversion using oxygen-mixed gas on a Cu network cathode and tailored anode.

Electrochemical CO2 reduction (eCO2R) by direct introduction of 60% air-containing CO2 mixed gas was demonstrated using a porous Cu network cathode formed on a hydrophobic gas diffusion layer (Cu/P-GDL). Cu/P-GDL exhibited eCO2R using the mixed gas with a remarkable faradaic efficiency of 85% for the production of C2+ chemicals, whereas a Cu cathode constructed on a conventional carbon gas diffusion layer (Cu/C-GDL) produced neither eCO2R products nor H2. Furthermore, the electrolyzer with Cu/P-GDL and optimized anode configuration achieved a partial current density of 132 mA cm-2 for C2+ chemicals even in the presence of 12% O2. Demonstration of eCO2R with impure CO2 gas would greatly expand its future applications.

A critical review of carbon dioxide enhanced oil recovery in carbonate reservoirs

Carbon dioxide (CO2) enhanced oil recovery (EOR) in carbonate reservoirs is regarded as a promising EOR technology. However, the oil recovery factor of CO2 EOR is low due to the CO2 EOR mechanisms in carbonate reservoirs are not clear. In this study, the CO2 EOR in carbonate reservoirs is reviewed in detail. First, the carbonate reservoirs are characterized by strong heterogeneity, fractures and vugs with poor connectivity, complex fluid properties, leading to a variety of difficulties in drilling, acid fracturing and CO2 EOR. Second, CO2 EOR in carbonate reservoirs includes CO2 continuous injection, water-alternating-CO2 (WAG), carbonated water injection (CWI), CO2 foam and CO2 huff-n-puff. But the screening criterion for different CO2 injection schemes in carbonate reservoirs has not been established. Third, the mechanisms of the CO2 diffusion, CO2-oil interaction, and CO2-fluid-rock interaction are discussed. (1) The main experimental test method for CO2 diffusion coefficient is pressure decay, and the temperature of the CO2 diffusion coefficient test is 25–130 ℃, and the pressure is 0.772–34 MPa. But the matrix-fracture-vug system and CO2-fluid-rock interaction effects in the CO2 diffusion coefficient experiments, and the impure CO2 diffusion behavior and CO2 diffusion behavior in the oil–water mixture have not been studied. (2) The main mechanism of pure CO2 flooding for EOR has been studied, but the development of impure CO2 oil interaction and complex the matrix-fracture-vug system are unclear. (3) The CO2-fluid-rock interactions have great influences to CO2 EOR in the carbonate reservoirs. But CO2-fluid-rock interactions in-situ formation state is still unclear. Fourth, pilot test studies in carbonate reservoirsare discussed, and the challenges of CO2 EOR in carbonate reservoirs are pointed out. The findings of this study can help for better understanding of CO2 EOR mechanism in carbonate reservoirs, and it also proposes some future clues of CO2 EOR in carbonate reservoirs.

Pilot-scale study of biomethanation in biological trickle bed reactors converting impure CO2 from a Full-scale biogas plant

Research within biological methanation has been a great development using biotrickling filters (BTF), as a power-to-x solution, but research within up scaling is missing. This study investigates the commercial potential of biomethanation in BTF by operating two 1 m3 reactors which was implemented into a full-scale biogas plant. Several areas were investigated, such as enrichment and start-up, long-term steady state operation, serial operation, and intermittent feed. A methane productivity of 9.44 NmCH43 mR-3 day-1 with a product gas of 95.7 % CH4 was obtained for parallel operation, whereas during serial operation a methane productivity of 10.6 NmCH43 mR-3 day-1 at 97.4 % CH4 was achieved. The flexibility of the biomethanation was demonstrated with unintentional loss of H2 feed in periods of 12 to 72 h, where initial performance was regained within 6 to 12 h. The results from this study demonstrate the potential for commercial use of biomethanation in BTF for future Power-to-X solutions.

Depressurization and heat transfer during leakage of supercritical CO2 from a pipeline

AbstractThe carbon capture, utilization and storage (CCUS) technology can effectively improve global climate change. Extensive pipelines are used in CCUS to transport large amounts of pure and impure supercritical CO2(S‐CO2) from captured sites to storage, owing to pipelines being an economical and efficient means of transportation. In the event of an accidental rupture of a supercritical CO2 pipeline, causing substantial economic losses and catastrophic consequences to surroundings. Hence, it is necessary that the study of the pressure variation and temperature distribution of CO2 during pipeline blowdown contributes to understanding fracture initiation and propagation, as well as designing reliable pipelines. A laboratory‐scale setup is used to investigate the evolution of leakage behaviours and analyze heat transfer of pure and impure supercritical CO2 with different release orifices. The depressurization process, variation of inner and wall of pipeline temperature were measured. Results show that the larger is the leakage orifice, the lower is the minimum temperature of the inner pipeline. The larger is the concentrations of nitrogen (N2) in supercritical CO2 mixture, the lower is the minimum temperature of the inner pipeline, and the higher is the risk of pipeline brittle fracture. During the entire release process, the Nusselt number (Nu) was determined based on measurements to discuss the process of heat transfer between the CO2 mixture and pipeline wall. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Metal Mobilization From CO2 Storage Cap-Rocks: Experimental Reactions With Pure CO2 or CO2 SO2 NO

CO2 geological storage will be needed as part of the transition to lower greenhouse gas emissions. During CO2 storage, the mobilization of metals from minerals to formation water via CO2 water rock reactions may be a concern for water quality. The sources, behavior, and fate of metals, however, are not well understood. Metals in minerals of calcite cemented sandstone, feldspar-rich sandstone, and ironstone seal drill cores from a target storage site were characterized. The cores were reacted with low-salinity water and pure supercritical CO2 or impure CO2 with SO2 and nitric oxide (NO), under reservoir conditions. Calcite cemented core underwent calcite dissolution with chlorite, plagioclase, and sulfide alteration. The highest concentrations of calcium and manganese were released in the reaction of calcite cemented sandstone seal, with the lowest mobilized arsenic concentration. Pure CO2 reaction of the feldspar-rich sandstone seal resulted in calcite dissolution, with plagioclase, chlorite, kaolinite, illite, and sulfides corroded. Impure CO2 reaction of the feldspar-rich sandstone led to additional corrosion of apatite, pyrite, and sphalerite cements. Generally, dissolved iron, lead, zinc, and arsenic were released and then re-precipitated in oxide minerals or adsorbed. Calcium, manganese, and strontium were released primarily from calcite cement dissolution. Plagioclase corrosion was a second source of dissolved strontium, and chlorite dissolution a second source of manganese. Although sulfides contained higher concentrations of metals, the higher reactivity of carbonates meant that the latter were the main sources contributing to dissolved metal concentrations. The mineral content of the seal cores, and the injected gas mixture, had an impact on the type and concentration of metals released. The ubiquitous presence of carbonate minerals means that this study is applicable to understanding the potential risk factors for water quality changes, and the mobilization and fate of environmentally regulated metals, in both CO2 storage complexes and overlying drinking water aquifers worldwide.

Ni-Fe bimetallic hexaaluminate for efficient reduction of O2-containing CO2 via chemical looping

Direct utilization of impure CO2, especially with O2 impurities, bridges the technology gap between carbon capture and utilization (CCU), by reducing the overall carbon footprint. In this work, we developed Ni-substituted LaFe3Al9O19 hexaaluminates as oxygen carriers to efficiently reduce CO2 into high value-added substances, with the presence of a large amount of O2 impurities via a chemical looping scheme. With O2 to CO2 ratio of 0.857:10, LaFe2.9Ni0.1Al9O19 exhibited high CO2 conversion of ∼ 92% and synthesis gas yield of ∼ 4.26 mmol/g with a suitable H2/CO ratio (∼ 2.0) during the redox cycles. Even with extremely high content of O2 (O2 to CO2 ratio of 38:10), an acceptable CO2 conversion (over 50%) and synthesis gas yield (∼ 3.84 mmol/g, H2/CO ratio, ∼ 2.0) were obtained. These results benefited from the synergistic effect of Ni and Fe that low amounts of Ni sufficed to activate methane splitting and Fe increased the resistance to coke formation during CH4 partial oxidation. Meanwhile, in O2-containing CO2 splitting step, Ni-Fe bimetallic hexaaluminate enhanced the ability of the oxygen carriers to activate CO2 and suppressed the oxidative competition of O2 compared with pure Fe hexaaluminate. Our work presents a promising approach for direct utilization of impure CO2 and achieving carbon–neutral economic development.

Towards defining reasonable minimum composition thresholds – Impacts of variable CO2 stream compositions on transport, injection and storage

To set up recommendations on how to define “reasonable minimum composition thresholds” for CO2 streams to access CO2 pipeline networks, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the CCS chain. All investigations were based on a generic “CCS cluster scenario” in which CO2 streams captured from a spatial cluster of eleven emitters (seven fossil-fired power plants, two cement plants, one refinery and one steel mill) are collected in a regional pipeline network. The resulting CO2 stream (19.78 Mio t impure CO2 per year) is transported in a trunk line (onshore and offshore) and injected into five generic replicate storage structures (Buntsandstein saline aquifers) offshore. Experimental investigations and modeling of selected impacts revealed beneficial as well as adverse impacts of different impurities and their combinations. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the considered variable compositions and mass flow rates were observed. We recommend to define minimum composition thresholds for each specific CCS project through limiting i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of concentrations of critical impurities, and defining impurity combinations to be avoided.

Experimental Determination of the Interfacial Tension and Swelling Factors of Bakken and Duvernay Oils with CO2, Impure CO2, Methane, Ethane, and Propane

Experimental Determination of the Interfacial Tension and Swelling Factors of Bakken and Duvernay Oils with CO₂, Impure CO₂, Methane, Ethane, and Propane

Recommendations for the selection of equation of state during design and operation of impure CO2 transport and storage

Recommendations for the selection of equation of state during design and operation of impure CO2 transport and storage

Chemical looping co-conversion of CH4 and CO2 using Fe2O3/Al2O3 pellets as both oxygen carrier and catalyst in a fluidized bed reactor

Chemical looping reforming of CH4 (CH4-CLR) is a safe and efficient CH4 upgrading technology for syngas production. The Fe2O3-based oxygen carriers (OCs) possess a higher potential for CH4-CLR among so many transition metal oxides as high syngas selectivity can be obtained from partial CH4 oxidation by OCs with the step-by-step reduction of Fe3+/Fe2+ to Fe0. However, the impurity CO2 in CH4-source feed gas, when using Fe2O3-based OCs, often causes the inhibition of reaction between CH4 and OCs resulting in no partial CH4 oxidation to syngas. The present work has employed the Fe2O3/Al2O3 pellets as OCs with introducing the fully reduced same pellets as a catalyst in a bubbling fluidized-bed reactor to eliminate the inhibition effect of CO2 during CH4-CLR. It has been demonstrated that the Fe species with low valent, e.g., Fe0, in the catalyst can effectively catalyze the dry CH4 reforming. Thus, the CO2 has been consumed before contacting with Fe2O3-based OCs and the inhibition effect of CO2 has been eliminated. Meanwhile, both CO2 and CH4 can be converted to syngas in the reducer leading to an opportunity for CO2 utilization. With the help of the catalyst of reduced OCs, not only the CO2 in the feed gas but also that formed from full CH4 oxidation by Fe2O3/Al2O3 at the early CH4 reforming stage is converted into syngas of CO and H2. Semi-continuous cyclic CH4-CLR test has demonstrated the good stability of both Fe2O3/Al2O3 OC and counterpart catalyst, which suggests the potential of such OC/catalyst pair in practical applications.