23 results found
Azzan H, Danaci D, Pini R, 2023, Unary adsorption equilibria of hydrogen, nitrogen and carbon dioxide on y-type zeolites at temperatures from 298 to 393 k and at pressures up to 3 MPA, Journal of Chemical and Engineering Data, ISSN: 0021-9568
The equilibrium adsorption of CO2, N2, and H2 on commercially available Zeolite H–Y, Na–Y, and cation-exchanged NaTMA–Y was measured up to 3 MPa at 298.15, 313.15, 333.15, 353.15, and 393.15 K gravimetrically using a magnetic suspension balance. The chemical and textural characterization of the materials was carried out by thermogravimetric analysis, helium gravimetry, and N2 (77 K) physisorption. We report the excess and net isotherms as measured and estimates of the absolute adsorption isotherms. The latter are modeled using the simplified statistical isotherm (SSI) model to evaluate adsorbate–adsorbent interactions and parametrize the data for process modeling. When reported per unit volume of zeolite supercage, the SSI model indicates that the saturation capacity for a given gas takes the same value for the three adsorbents. The Henry’s constants predicted by the model show a strong effect of the cation on the affinity of each adsorbate.
Saenz Cavazos P, Hunter-Sellars E, Iacomi P, et al., 2023, Evaluating solid sorbents for CO2 capture: linking material properties and process efficiency via adsorption performance, Frontiers in Energy Research, Vol: 11, Pages: 1-22, ISSN: 2296-598X
Expanding populations and growing economies result in higher energy needs. Meeting this increasing demand, while lowering carbon emissions, calls for a broad energy mix and commercial deployment of solutions like carbon capture and carbon removal technologies. The scale-up of these solutions is partially hindered by the lack of materials-related information, particularly in the case of solid adsorption-based carbon capture technologies. Furthermore, experimental measurement parameters used and how data is presented lack uniformity, which makes material comparisons extremely difficult. This review examines the current state of solid sorbent characterization for carbon capture, exploring physical and chemical properties, performance parameters, and process indicators. Adsorbent performance parameters demonstrate to be the crucial link between intrinsic material properties and the overall adsorption process effectiveness and therefore are the focus of this work. This paper outlines the relevant techniques used to measure Key Performance Indicators (KPIs) related to adsorption performance such as CO2 adsorption capacity, selectivity, kinetics, ease of regeneration, stability, adsorbent cost, and environmental impact. Additionally, this study highlights the relevant experimental conditions for diluted versus concentrated CO2 streams. Lastly, efforts in harmonizing experimental data sets are considered, and an outlook on solid sorbent characterization for carbon capture processes is presented. Overall, the aim of this work is to provide the reader a critical understanding of KPIs from atomic to process scale, highlighting the importance of experimental data throughout.
L'Hermitte A, Azzan H, Yio MHN, et al., 2023, Effect of surface functionalization on the moisture stability and sorption properties of porous boron nitride, Microporous and Mesoporous Materials, Vol: 352, Pages: 1-13, ISSN: 1387-1811
Porous boron nitride (BN) is a promising adsorbent owing to its high surface area and porosity, as well as thermal and oxidative stability. It has been explored in the past decade for applications in gas and liquid separations, such as CO2 capture and water cleaning. However, the material has displayed hydrolytic instability. Owing to the presence of moisture in most industrial settings, whether it is for storage or cyclic adsorption processes, ensuring the moisture stability of an adsorbent is crucial. While this topic has been researched for other adsorbents such as zeolites and metal organic frameworks (MOFs), little is known on controlling the hydrolytic stability of porous BN. In this study, we propose a method to enhance porous BN's hydrolytic stability via surface functionalization using a fluoroalkylsilane. We explored two different routes of functionalization: (i) functionalization of porous BN powder followed by pelletization (route 1) and (ii) coating of porous BN pellets with fluoroalkylsilane (route 2). Spectroscopic, analytical and imaging techniques confirmed the functionalization process qualitatively and quantitatively. We subjected the functionalized samples to moisture exposure at 54% RH (similar to common storage conditions) and 92% RH (similar to flue gas stream conditions with high moisture content), and characterized them to probe their resistance to moisture. We also investigated their equilibrium and kinetic sorption properties in the context of CO2/N2 separation. Both routes produced materials with enhanced moisture stability. However, we noted differences between both functionalization routes. Route 2 produced a sample with a higher grafting yield and hydrophobic nature, and therefore better resistance to moisture exposure than route 1. From a sorption point of view, despite reduced porosity, the functionalized samples maintain reasonable CO2 uptakes. The functionalization led to changes in the textural features of the samples, which cause
Danaci D, Pulidori E, Bernazzani L, et al., 2023, Evaluating the CO<inf>2</inf> capture performance of a “phase-change” metal-organic framework in a pressure-vacuum swing adsorption process, Molecular Systems Design and Engineering
Metal-organic frameworks (MOFs) that display step-shaped adsorption isotherms, i.e., “phase-change” MOFs, represent a relatively small subset of all known MOFs. Yet, they are rapidly emerging as promising sorbents to achieve excellent gas separation performances with little energy demand. In this work, we assessed F4_MIL-140A(Ce), a recently discovered “phase-change” MOF adsorbent, for CO2 capture in two scenarios using a pressure-vacuum swing adsorption process, namely a coal-fired power plant flue gas (12.5%mol CO2), and a steel plant flue gas (25.5%mol CO2). Four CO2 and three N2 adsorption isotherms were collected on F4_MIL-140A(Ce) over a range of temperatures and modelled using a bespoke equation for step-shaped isotherms. We accurately measured the heat capacity of F4_MIL-140A(Ce), a key thermodynamic property for a sorbent, using a method based on differential scanning calorimetry that overcomes the issues associated with the poor thermal conductivity of MOF powders. We then used these experimental data as input in a process optimisation framework and we compared the CO2 capture performance of F4_MIL-140A(Ce) to that of other “canonical” sorbents, including, zeolite 13X, activated carbon and three MOFs (i.e., HKUST-1, UTSA-16 and CALF-20). We found that F4_MIL-140A(Ce) has the potential to perform better than other sorbents, in terms of recovery and purity, under most of the simulated process conditions. We attribute such promising performance to the non-hysteretic step-shaped isotherm, the low uptake capacity for N2 and the mild heat of CO2 adsorption displayed by F4_MIL-140A(Ce).
Xiong Y, Tian T, L'Hermitte A, et al., 2022, Using silver exchange to achieve high uptake and selectivity for propylene/ propane separation in zeolite Y, Chemical Engineering Journal, Vol: 446, ISSN: 1385-8947
Adsorptive separation of propylene and propane, an important step of polypropylene production, is more energy-efficient than distillation. However, the challenge lies in the design of an adsorbent which exhibits both high selectivity and uptake. Herein, we hypothesise that enhancing the propylene affinity of the adsorption sites while keeping a suitable pore size can address this challenge. To do so, we performed silver exchange of a commercial zeolite Y, thereby making the adsorbent design easily scalable. We characterised the adsorbent using analytical, spectroscopic and imaging tools, tested its equilibrium and dynamic sorption properties using volumetric and gravimetric techniques and compared its performance to those of state-of-the-art adsorbents as well as other silver-functionalised adsorbents. The silver-exchanged zeolite Y (Ag-Y) exhibited one of the best selectivity vs uptake performances reported so far. Ag-Y also displayed fast adsorption kinetics and reversible propylene sorption, making it a promising new benchmark for propylene/propane separation. Synchrotron-based pair distribution function analyses identified the silver cations’ location which confirmed that the silver sites are easily accessible to the adsorbates. This aspect can, in part, explain the propylene/propane separation performance observed. The overall design strategy proposed here to enhance sorption site affinity and maintain pore size could be extended to other adsorbents and support the deployment of adsorption technology for propylene/propane separation.
Osterrieth JWM, Rampersad J, Madden D, et al., 2022, How Reproducible are Surface Areas Calculated from the BET Equation?, ADVANCED MATERIALS, Vol: 34, ISSN: 0935-9648
Sunny N, Bernardi A, Danaci D, et al., 2022, A pathway towards net-zero emissions in oil refineries, Frontiers in Chemical Engineering, Vol: 4, ISSN: 2673-2718
Rapid industrialization and urbanization have increased the demand for both energy and mobility services across the globe, with accompanying increases in greenhouse gas emissions. This short paper analyzes strategic measures for the abatement of CO2 emissions from oil refinery operations. A case study involving a large conversion refinery shows that the use of post-combustion carbon capture and storage (CCS) may only be practical for large combined emission point sources, leaving about 30% of site-wide emissions unaddressed. A combination of post-combustion CCS with a CO2 capture rate well above 90% and other mitigation measures such as fuel substitution and emission offsets is needed to transition towards carbon-neutral refinery operations. All of these technologies must be configured to minimize environmental burden shifting and scope 2 emissions, whilst doing so cost-effectively to improve energy access and affordability. In the long run, scope 3 emissions from the combustion of refinery products and flaring must also be addressed. The use of synthetic fuels and alternative feedstocks such as liquefied plastic waste, instead of crude oil, could present a growth opportunity in a circular carbon economy.
Xiong Y, Woodward RT, Danaci D, et al., 2021, Understanding trade-offs in adsorption capacity, selectivity and kinetics for propylene/propane separation using composites of activated carbon and hypercrosslinked polymer, CHEMICAL ENGINEERING JOURNAL, Vol: 426, ISSN: 1385-8947
Danaci D, Bui M, Petit C, et al., 2021, En route to zerio emissions for power and industry with amine-based post-combustion capture, Environmental Science and Technology (Washington), Vol: 55, Pages: 10619-10632, ISSN: 0013-936X
As more countries commit to a net-zero GHG emission target, we need a whole energy and industrial system approach to decarbonization rather than focus on individual emitters. This paper presents a techno-economic analysis of monoethanolamine-based post-combustion capture to explore opportunities over a diverse range of power and industrial applications. The following ranges were investigated: feed gas flow rate between 1–1000 kg ·s–1, gas CO2 concentrations of 2–42%mol, capture rates of 70–99%, and interest rates of 2–20%. The economies of scale are evident when the flue gas flow rate is <20 kg ·s–1 and gas concentration is below 20%mol CO2. In most cases, increasing the capture rate from 90 to 95% has a negligible impact on capture cost, thereby reducing CO2 emissions at virtually no additional cost. The majority of the investigated space has an operating cost fraction above 50%. In these instances, reducing the cost of capital (i.e., interest rate) has a minor impact on the capture cost. Instead, it would be more beneficial to reduce steam requirements. We also provide a surrogate model which can evaluate capture cost from inputs of the gas flow rate, CO2 composition, capture rate, interest rate, steam cost, and electricity cost.
Tian T, Hou J, Ansari H, et al., 2021, Mechanically stable structured porous boron nitride with high volumetric adsorption capacity, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 9, Pages: 13366-13373, ISSN: 2050-7488
Danaci D, Webley PA, Petit C, 2021, Guidelines for techno-economic analysis of adsorption processes, Frontiers in Chemical Engineering, Vol: 2, ISSN: 2673-2718
Techno-economic analyses (TEAs) of CO2 capture technologies have risen in popularity, due to growing interest in meeting CO2 emissions reduction targets. Adsorption processes are one of the technologies proposed for CO2 capture, and although difficult, standardisation of TEAs for adsorption should be attempted. The reason is that TEAs are often referred to as input data to other forms of modelling, to guide policy, and act as summaries for those unfamiliar with adsorption processes. Herein, we discuss the aspects that should be considered when conducting TEAs for CO2 adsorption processes, we present the implications of choices made at the TEA stage and offer guidance on best practice. Overall, our aim is to make TEAs of adsorption processes more widely accessible to the adsorption community, and also more generally to communities engaged in the evaluation of CCS technologies.
Men Y, Fang X, Gu Q, et al., 2020, Synthesis of Ni5Ga3 catalyst by Hydrotalcite-like compound (HTlc) precursors for CO2 hydrogenation to methanol, APPLIED CATALYSIS B-ENVIRONMENTAL, Vol: 275, ISSN: 0926-3373
Danaci D, Bui M, Mac Dowell N, et al., 2020, Exploring the limits of adsorption-based CO2 capture using MOFs with PVSA – from molecular design to process economics, Molecular Systems Design and Engineering, Vol: 5, Pages: 212-231, ISSN: 2058-9689
Metal-organic frameworks (MOFs) have taken the materials science world by storm, with potentials of near infinite possibilities and the panacea for adsorption-based carbon capture. Yet, no pilot-scale (or larger-scale) study exists on MOFs for carbon capture. Beyond material scalability issues, this clear gap between the scientific and engineering literature relates to the absence of suitable and accessible assessment of MOFs in an adsorption process. Here, we have developed a simple adsorbent screening tool with process economics to evaluate adsorbents for post-combustion capture, while also considering factors relevant to industry. Specifically, we have assessed the 25 adsorbents (22 MOFs, 2 zeolites, 1 activated carbon) against performance constraints – i.e. CO2 purity and recovery – and cost. We have considered four different CO2 capture scenarios to represent a range of CO2 inlet concentrations. The cost is compared to that of amine-based solvents for which a corresponding model was developed. Using the model developed, we have conceptually assessed the materials properties and process parameters influencing the purity, recovery and cost in order to design the ‘best’ adsorbent. We have also set-up a tool for readers to screen their own adsorbent. In this contribution, we show that minimal N2 adsorption and moderate enthalpies of adsorption are key in obtaining good process performance and reducing cost. This stands in contrast to the popular approaches of maximizing CO2 capacity or surface area. Of the 22 MOFs evaluated, UTSA-16 shows the best performance and lowest cost for post-combustion capture, having performance in-line with the benchmark, zeolite 13X. Mg-MOF-74 performs poorly. The cost of using the adsorbents remains overall higher than that of an amine-based absorption process. Ultimately, this study provides specific directions for material scientists to design adsorbents and assess their performance at the process scale. This
Wu F, Zhao Q, Tao L, et al., 2019, Solubility of carbon monoxide and hydrogen in methanol and methyl formate: 298-373 K and 0.3-3.3 MPa, Journal of Chemical and Engineering Data, Vol: 64, Pages: 5609-5621, ISSN: 0021-9568
In this study, we report the solubility of the gases carbon monoxide (CO) and hydrogen (H2) in methanol and methyl formate using the synthetic isothermal method via total pressure measurement. The motivation for these measurements is to provide data to better understand the reactions occurring during a two-step gas–liquid methanol synthesis method via a methyl formate pathway. Specifically, the solubility of the pairs CO–methanol, CO–methyl formate, H2–methanol, and H2–methyl formate was measured at different pressures (0.3–3.3 MPa) and temperatures (298–373 K). The solubility of H2 in methanol and methyl formate is lower than that of CO in methanol and methyl formate. The solubility of both H2 and CO in methanol and methyl formate increases with temperature. Thermodynamic properties, including the Gibbs free energy, the enthalpy of dissolution, and the entropy of dissolution, were determined and are within expected ranges. The enthalpy of dissolution is positive suggesting stronger solute–solute than solute–solvent interactions. The modified Peng–Robinson equation of state was used to calculate the gas–liquid equilibrium and can successfully correlate and represent the experimental solubility data within an error of ±5%.
Danaci D, 2019, CO2 capture by adsorption processes, Carbon Capture and Storage, Editors: Bui, Mac Dowell, Publisher: Royal Society of Chemistry, Pages: 106-167, ISBN: 978-1-78801-145-7
Adsorption is a reliable process technology that has been in use since the 1960s for gas separation applications. Since the mid 90s, interest has grown around CO2 emissions abatement with adsorption being one of the first technologies considered. There has since been significant research and development on both the materials science, and engineering aspects of adsorption for CO2 capture. Adsorbents with extensive histories such as zeolites, activated carbons, and layered double hydroxides have experienced resurgences, and novel adsorbents such as metal–organic frameworks and microporous organic polymers were conceived. Adsorption-based separations are cyclic processes, and methods to improve the attainable purity and recovery of the CO2 have also been investigated; this work has shown that 90%mol recovery and 95%mol purity are possible for post-combustion capture. Work is also underway to improve the throughput of gas–solid contacting devices as a form of process intensification, which is required for high volumetric flow rate applications. Although there are still some concerns around the stability of some adsorbents to impurities, there have been meaningful and significant advancements over the last 20–25 years. These have made adsorption a viable technology for carbon capture applications.
Danaci D, Bui M, Dowell NM, et al., 2019, An adsorbent screening tool with process economics for carbon capture by PVSA
Danaci D, 2018, Carbon dioxide separation from natural gas: evaluation of adsorbents and influence of process variables
Kanehashi S, Chen GQ, Danaci D, et al., 2017, Can the addition of carbon nanoparticles to a polyimide membrane reduce plasticization?, SEPARATION AND PURIFICATION TECHNOLOGY, Vol: 183, Pages: 333-340, ISSN: 1383-5866
Tang WNH, Danaci D, Singh R, et al., 2016, Oxygen selective iron and cobalt-metalloporphyrin polymers - Extraordinary selectivity at low temperature, MICROPOROUS AND MESOPOROUS MATERIALS, Vol: 222, Pages: 63-72, ISSN: 1387-1811
Danaci D, Singh R, Xiao P, et al., 2015, Assessment of ZIF materials for CO<sub>2</sub> capture from high pressure natural gas streams, CHEMICAL ENGINEERING JOURNAL, Vol: 280, Pages: 486-493, ISSN: 1385-8947
Remy T, Gobechiya E, Danaci D, et al., 2014, Biogas upgrading through kinetic separation of carbon dioxide and methane over Rb- and Cs-ZK-5 zeolites, RSC ADVANCES, Vol: 4, Pages: 62511-62524, ISSN: 2046-2069
Shang J, Li G, Singh R, et al., 2014, Adsorption of CO<sub>2</sub>, N<sub>2</sub>, and CH<sub>4</sub> in Cs-exchanged chabazite: A combination of van der Waals density functional theory calculations and experiment study, JOURNAL OF CHEMICAL PHYSICS, Vol: 140, ISSN: 0021-9606
Duan H, Yang Y, Singh R, et al., 2014, Mesoporous Carbon-supported Cu/ZnO for Methanol Synthesis from Carbon Dioxide, AUSTRALIAN JOURNAL OF CHEMISTRY, Vol: 67, Pages: 907-914, ISSN: 0004-9425
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