CO2 Capture And Utilization Research Articles

CO2 valorisation from lime production via Columbus process to produce E-methane for transport sector – A comprehensive life cycle assessment

In the next decades, CO2 capture and utilisation (CCU) technologies can contribute to climate change mitigation. The Columbus project is an example of a CCU initiative in which CO2 is captured from lime production and converted into E-methane via CO2 methanation. E-methane can serve as fuel for ships and lorries to replace heavy fuel oil and diesel, respectively. This paper aims to assess the environmental impacts of E-methane production via the Columbus process, powered by renewable electricity, and its utilisation in the transport sector benchmarked to conventional fuel production (references) through life cycle assessment (LCA). A basket of products approach was used to also consider the co-products obtained from the Columbus process in the assessment. Both emission and resource based indicators were selected for the LCA. The results show that E-methane production and its utilisation in ships and lorries result in a decrease of the impact on climate change (35 %), particulate matter formation (94 %) and fossil resource use (85 %) compared to the references. For this comparison, the conventional production of the co-products was also taken into account. However, the production and utilisation of this fuel consumes more minerals and metals than the references. The higher mineral and metal extraction from the environment can be explained by the construction of the solar panels required to provide electricity for electrolysis. Future research should focus on the social acceptance and techno-economic assessment of the Columbus process.

Carbon Dioxide Capture and Conversion Using Metal-Organic Framework (MOF) Materials: A Comprehensive Review.

The escalating threat of anthropogenic climate change has spurred an urgent quest for innovative CO2 capture and utilization (CCU) technologies. Metal-organic frameworks (MOFs) have emerged as prominent candidates in CO2 capture and conversion due to their large specific surface area, well-defined porous structure, and tunable chemical properties. This review unveils the latest advancements in MOF-based materials specifically designed for superior CO2 adsorption, precise separation, advanced photocatalytic and electrocatalytic CO2 reduction, progressive CO2 hydrogenation, and dual functionalities. We explore the strategies that enhance MOF efficiency and examine the challenges of and opportunities afforded by transitioning from laboratory research to industrial application. Looking ahead, this review offers a visionary perspective on harnessing MOFs for the sustainable capture and conversion of CO2.

Carbon Management – From Vision to Industrial Application

AbstractCarbon is a key element in industrial production, but CO2 is also a greenhouse gas whose release into the atmosphere must be avoided. If its generation cannot be avoided for process‐related reasons, then a comprehensive carbon management is required to enable climate‐neutral production in industry. In the Carbon2Chem® project, partners from industry and science are successfully researching technical components that enable the implementation of concepts for CO2 capture and utilization (CCU) as part of carbon management.

Waste CO2 capture and utilization for methanol production via a novel membrane contactor reactor process: Techno-economic analysis (TEA), and comparison with other existing and emerging technologies

We introduced recently a CO2 capture and utilization (CCU) technology that produces methanol (MeOH), from waste CO2 employing a novel configuration combining a reverse water gas shift reactor (RWGSR) with a membrane contactor reactor for MeOH synthesis (MeS-MCR). The integrated RWGSR/MeS-MCR process overcomes the challenges direct CO2 conversion into MeOH faces and achieves carbon conversions exceeding 80 %, significantly surpassing the equilibrium conversion of ∼ 20–30 % for the MeS reaction. In this study, a techno-economic analysis (TEA) was conducted on the RWGSR/MeS-MCR process along with four other CO2-to-MeOH CCU processes. Key economic parameters, as well as the energy efficiency, were analyzed with respect to CO2 and renewable hydrogen (H2) costs and plant capacity. The study revealed that the RWGSR/MeS-MCR technology has the highest energy efficiency and the best economic performance among all the technologies investigated. All technologies offer the significant societal benefit of capturing and utilizing waste CO2, but under present CO2 and renewable H2 costs, they cannot currently compete cost-wise with conventional MeOH production methods. However, under a future scenario whereby government incentives lower the CO2 cost and technological advances decrease the price of renewable H2, the proposed RWGSR/MeS-MCR process and another catalytic technology (CAMERE) become price competitive.

CO2 capture and in-situ conversion to organic molecules

To address the CO2 accumulation in atmosphere, various initiatives have been proposed, among which CO2 capture and utilization (CCU) is regarded as an appealing strategy to reconcile carbon emission and resource utilization. Especially, integrated CO2 capture and utilization (ICCU), i.e. performing CO2 capture and in-situ conversion can circumvent the energy-intensive CO2 desorption step and thus facilitate establishing step- and energy-efficient process, rendering the conversion at mild conditions particularly at low pressure due to substantial activation upon CO2 uptake. However, CO2 capture and in-situ conversion is not the simple add-up of these two processes. Its successful implementation relies on the harmonization of CO2 capture reagents, substrates and the corresponding catalysts. By far, tremendous efforts have been made in this field and a plethora of CO2 capture reagents including inorganic bases, organic bases, ionic liquids and carbonaceous materials have been utilized to capture CO2 and the conversion protocols such as hydrogenation, cycloaddition, carboxylative cyclization etc. have been explored for these captured CO2. As a result, the valuable products containing methanol, methane, carbonates, carbamates, oxazolidinones, ureas, and quinazolinone have been obtained from CO2 and more importantly, the CO2 chemistry theory is also enriched via investigating the structure and reactivity of the captured CO2 in various reactions. In this review, we summarize the progress on CO2 capture and in-situ conversion based on the reaction types and corresponding CO2 absorbents. It’s hoped that this review can shed light on the design of CO2 capture and in-situ conversion and inspire the further development of this field.

Prospects for green steelmaking technology with low carbon emissions in China

AbstractThe steel industry is a major source of CO2 emissions, and thus, the mitigation of carbon emissions is the most pressing challenge in this sector. In this paper, international environmental governance in the steel industry is reviewed, and the current state of development of low‐carbon technologies is discussed. Additionally, low‐carbon pathways for the steel industry at the current time are proposed, emphasizing prevention and treatment strategies. Furthermore, the prospects of low‐carbon technologies are explored from the perspective of transitioning the energy structure to a “carbon–electricity–hydrogen” relationship. Overall, steel enterprises should adopt hydrogen‐rich metallurgical technologies that are compatible with current needs and process flows in the short term, based on the carbon substitution with hydrogen (prevention) and the CCU (CO2 capture and utilization) concepts (treatment). Additionally, the capture and utilization of CO2 for steelmaking, which can assist in achieving short‐term emission reduction targets but is not a long‐term solution, is discussed. In conclusion, in the long term, the carbon metallurgical process should be gradually supplanted by a hydrogen–electric synergistic approach, thus transforming the energy structure of existing steelmaking processes and attaining near‐zero carbon emission steelmaking technology.

Unraveling the Potential of Electrochemical pH-Swing Processes for Carbon Dioxide Capture and Utilization.

Global warming, driven by the accumulation of anthropogenic greenhouse gases, particularly CO2, in the atmosphere, has garnered significant attention due to its detrimental environmental impacts. To combat this critical issue, the deployment of CO2 capture and utilization (CCU) strategies has been considered as one of the technology-based solutions, leading to extensive scientific and engineering research. Electrochemical pH-swing (EPS) processes offer a promising approach to diverse CCU pathways, such as the delivery of pure CO2 gas, the delivery of bicarbonate (e.g., for microalgae cultivation), and the formation of carbonate minerals. In this study, we discuss several CCU pathways using EPS and provide an in-depth analysis of its mechanisms and potential applications, outlining its limitations from both thermodynamic and kinetic standpoints. The EPS process has demonstrated remarkable capabilities, achieving a CO2 capture efficiency of over 90% and unlocking valuable opportunities for CCU applications. We also develop an initial techno-economic assessment and provide the perspectives and challenges for future development and deployment of EPS. This study sheds light on the integration of EPS with CCU, closing the carbon cycle by effectively utilizing the products generated through the process, such as carbonate minerals and bicarbonate solution. For instance, the bicarbonate product can serve as a viable feedstock for bicarbonate-based microalgae production systems, with the added benefit of reducing costs by 40-80% compared to traditional gaseous CO2 delivery approaches. By integration of electrochemical technologies with CCU methods, this study underscores the immense potential for mitigating CO2 emissions and advancing sustainable practices to combat global warming. This study not only addresses the urgent need for effective solutions but also paves the way for a greener and more sustainable future.

(Invited) Electrochemical Synthesis of Diamond from Carbon Dioxide in Molten Lithium Chloride-Potassium Chloride Systems

IntroductionIn order to achieve carbon neutrality by 2050, not only the CO2 capture and storage (CCS) but also the CO2 capture and utilization (CCU) is necessary. Here, electrochemical CO2 conversion technology in molten salt is considered to be one of the promising candidates for CCU [1,2]. In this study, we aimed to convert CO2 into diamond, which is one of the most valuable carbon materials. As a first step, we investigated the electrochemical synthesis of diamond in molten LiCl-KCl systems containing K2CO3 and KOH, based on the premise that CO2 dissolves as CO3 2- in molten salts containing O2-. As a result, micro-Raman spectroscopy and scanning electron microscopy (SEM) confirmed that a part of the deposits obtained by electrolysis were diamonds. As a second step, we attempted the electrochemical synthesis of diamond using CO2 as the actual raw material. Here, H2O was also bubbled in the molten salt in order to produce KOH. The deposits obtained by electrolysis were then analyzed by micro-Raman spectroscopy and SEM, which confirmed the synthesis of diamond.ExperimentalCyclic voltammetry and potentiostatic electrolysis were performed after adding K2CO3 and KOH to LiCl-KCl eutectic melts under an Ar atmosphere at 973 K. The working electrode was a Ni flag (Φ 3 × 0.1 mm) or Ni plate (5 mm × 10 mm × 0.1 mm), the counter electrode was a glass-like carbon rod, and the reference electrode was an Ag+/Ag electrode. The potential was calibrated with Li+/Li potential. After electrochemical measurements were performed, samples were prepared by potentiostatic electrolysis using the Ni plate electrodes. In the case where CO2 was used as a raw material, LiCl-KCl eutectic molten salt containing Li2O was prepared, and CO2 and H2O were bubbled into it in predetermined amounts, respectively. After electrochemical measurements, potentiostatic electrolysis was performed to prepare samples. The obtained samples were analyzed by SEM, EDX, and micro-Raman spectroscopy.Result and DiscussionFirst, electrochemical measurements in baths containing only K2CO3, only KOH, or both indicated that carbon deposition and hydrogen evolution proceed simultaneously in the potential range more negative than 1.2 V. Then, samples were prepared by potentiostatic electrolysis using Ni plate electrodes at 1.0 to 1.2 V (vs. Li+/Li). The charge density was unified at 10 C cm-2. As an example, the surface SEM image of a deposit obtained at 1.1 V in a bath containing 0.05 mol% K2CO3 and 1.0 mol% KOH is shown in Fig. 1(a). The EDX analysis of this area showed that only C and Ni from the substrate were detected. The result of micro-Raman spectroscopy of the sample is shown in Fig. 1(b), which shows a spectrum characteristic of diamond with a sharp peak at 1332 cm-1. Based on the results of these three analyses, the electrochemically synthesized angular particles were identified as diamond.On the day of the meeting, we will also present the results of electrolysis using CO2 as the raw material.AcknowledgmentA part of this work was supported by JSPS KAKENHI Grant Number 21K19024.

(Invited) Green Ammonia-Mediated CO2 Capture and Direct Electrochemical Reduction to Formate

Direct electrochemical conversion of CO2 capture solutions (instead of gaseous CO2) into valuable chemicals can circumvent the energy-intensive CO2 regeneration and pressurization steps. While commonly used CO2 capture agents include alkali and amine solutions, ammonia has been rarely investigated. In another aspect, mismanagement of reactive nitrogen (Nr) in waste has emerged as a major problem in water pollution to our ecosystems, causing severe eutrophication and health concerns. Sustainably recovering Nr [such as nitrate (NO3 −)-N] and converting it into green ammonia (NH3) could mitigate the environmental impacts of Nr and reduce the NH3 demand from the carbon-intensive Haber-Bosch process, as well as a possible CO2 capture agent due to its alkaline nature.In this talk, we will present our rencet research on integration of electrodialysis and electrocatalysis for ammonia synthesis from dilute waste Nr sources, and green ammonia-mediated CO2 capture (to ammonium bicarbonate, NH4HCO3) and subsequent reduction to ammonium formate (NH4HCO2) as a new approach to CO2 capture and utilization (CCU). We have demonstrated a record-high NO3 −-to-NH3 performance in a scalable, versatile, and cost-effective membrane-free alkaline electrolyzer (MFAEL): an unprecedented NH3 partial current density of 4.22 ± 0.25 A cm−2 with a faradaic efficiency of 84.5 ± 4.9%. We also discovered that an ammonium bicarbonate (NH4HCO3)-fed electrolyzer with an anion exchange membrane (AEM) outperforms the state-of-the-art KHCO3 electrolyzer with a bipolar membrane (BPM) owing to its favorable thermal decomposition property, which allows for a 3-fold increase in the in situ CO2 concentration, a maximum 23% increase in formate faradaic efficiency, and a 35% reduction in cell voltage by substituting BPM with the AEM. Our integrated process by combining NH4HCO3 electrolysis with CO2 capturing by on-site generated green ammonia from the electro-reduction of nitrate in MFAEL has shown a remarkable 99.8% utilization of CO2 capturing agent. Such a multi-purpose process may offer a sustainable route for the simultaneous removal of Nr wastes and streamlined CO2 capturing and upgrading to valuable chemicals.

An investigation of the Ni/carbonate interfaces on dual function materials in integrated CO2 capture and utilisation cycles

CO2 capture and utilisation (CCU) is a promising strategy to effectively mitigate the adverse greenhouse effects caused by CO2 emissions at an industrial scale. Through a process intensification strategy known as integrated CO2 capture and utilisation (ICCU), CO2 capture and catalytic CO2 conversion can be achieved in a single process with the use of dual function materials (DFMs), which are both CO2 sorbents and CO2 conversion catalysts. Given the significantly different operating conditions of ICCU from conventional catalytic CO2 hydrogenation, the catalytic mechanism of DFMs, especially during CO2 hydrogenation, needs to be thoroughly investigated. In this study, the relationship between the nature of the Ni/carbonate interfaces and the performance of Ni-based DFMs over ICCU cycles is systematically investigated. A series of Ni/alkaline earth carbonate DFMs were synthesised with varying Ca:Mg ratios to simulate different metal-carbonate model interfaces. At 400 °C, CH4 formation with nearly 100% CH4 selectivity was achieved on Ni/CaCO3 over 15 ICCU cycles. In general, Ni/CaCO3 interfaces correspond to higher CO2 conversion and higher CH4 selectivity than Ni/MgCO3 interfaces. Such trend may be attributed to the higher surface basicity of CaO and the higher thermal stability of CaCO3. As a consequence, the hydrogenation of the Ni/CaCO3 interface proceed via the formate pathway, in which carbonates are consecutively converted to surface formates, methoxyl, methyl species and eventually desorb as methane. This reaction model is applicable to the hydrogenation of both surface carbonate and bulk carbonates, although the former proceeds with much faster kinetics. On the weakly alkaline Ni/MgCO3 interface, MgCO3 preferentially decomposes to form gaseous CO2, which is subsequently hydrogenated via the reverse-water-gas-shift pathway, with CO as the key reaction intermediate. Interestingly, in situ infrared spectroscopy shows similar surface significant species during the direct hydrogenation of DFMs and during the conventional catalytic hydrogenation of molecular CO2, suggesting that the catalytic mechanisms during the two operating regimes are highly correlated.

Analyzing the effects of government policy and solar photovoltaic hydrogen production on promoting CO2 capture and utilization by using evolutionary game analysis

This study aims at proposing a public-private partnership project including the government (GOVT), coal-fired power plant (CTPP) and solar photovoltaic power plant (PVPP) toward carbon emission reduction and neutralization in China. The project is formed using the CO2 capture and utilization (CCU) and solar PV hydrogen production technologies. When all the participators cooperate, the influence of typical factors on the project is evaluated using the evolutionary game theory method. The results show that increasing the CCU subsidy can strengthen the participating intention of the CTPP but will reduce that of the GOVT. Improving the green electricity subsidy can strengthen the participating intention of the PVPP but will decrease that of the GOVT. To ensure the smooth running of the project, a relatively higher carbon emission penalty and a higher sales price of methanol should be ensured, the PVPP should control its daily working hours appropriately, and the proportion of electricity quantity of the PVPP used for hydrogen production should be increased. In this study, the suggested ranges of CCU and green electricity subsidy coefficients are 0.03–0.05 $/kWh and 0.0035–0.0045 $/kWh, the carbon emission penalty coefficient should be greater than 11 $/t, and the suggested range of daily working hours of the PVPP is 7–8 h.

Life cycle cost and environmental assessment of CO2 utilization in the beverage industry: A natural gas-fired power plant equipped with post-combustion CO2 capture

Besat is a natural gas-fired steam-turbine power plant in Tehran, Iran’s only power station equipped with a monoethanolamine-based post-combustion CO2 capture unit (PCCU). The PCCU operates at a low recovery rate of 4.7% and produces 58 t-CO2/day. Captured CO2 is encapsulated and sold to beverage companies for carbonated soft drink production. Before developing this CO2 capture and utilization (CCU) route, a beverage company like ZamZam produced CO2 on-site, capturing CO2 from flue gas of diesel-fired boilers using a 95%-efficient absorption-refrigeration unit. This paper conducts an attributional, comparative life-cycle assessment/costing of applying the CCU technology to supply the beverage industry with CO2. ReCiPe, cumulative energy demand, and AWARE impact assessment methods are adopted to assess changes in the life-cycle economic, energy, and environmental impacts of electricity, liquid CO2, and carbonated water supply chains with the CCU route. As per findings, the CCU route significantly improves the sustainability profile of liquid CO2 supply for carbonated water production. Compared to on-site production, the CCU route reduces the average economic, energy, and environmental impacts of liquid CO2 supply by 55, 44, and 62%, respectively. However, the figures for carbonated-water production are reduced by only 10.1, 0.85, and 0.77%, respectively, since associated impacts primarily result from citric acid and polyethylene terephthalate value chains rather than liquid CO2. The CCU route, in comparison, increases most environmental burdens of electricity generation. With an efficiency of 4.7%, the PCCU reduces the global warming potential of electricity generation by 6.22% while increasing average toxicity- and eutrophication-related impacts by 55 and 30%, respectively, and production costs by 8%.

Sustainability analyses of CO2 sequestration and CO2 utilization as competing options for mitigating CO2 emissions

CO2 capture and sequestration (CCS) and CO2 capture and utilization (CCU) are potential alternatives to mitigate CO2 emissions. There have been concerns regarding long-term geological impact of CCS and CCU requires co-reactant(s) for converting CO2 into value-added products. In this work, sustainability of CCS and CCU are assessed by simulating three processes. Each of these processes used post-combustion amine technique to capture CO2 from flue gas stream coming out of natural gas-based power plant. In the first process (CCS), captured CO2 undergoes sequestration whereas in the other two processes (CCU) CO2 reacts with hydrogen to produce methanol and dimethyl ether. Based on our technoeconomic assessment, total annualized cost of CCS process is 7.57% and 6.55% lower than CCU-methanol and CCU-DME processes, respectively. Thus, CCS is economically favourable over CCU. DME is found to be a favourable CCU-product owing to its higher market price as compared to methanol. Our analysis suggests that hydrogen price significantly impacts the technoeconomics of CCU processes. We have also demonstrated that at current market prices of methanol and DME, CCU process can be economical compared to CCS provided hydrogen price reduces to $778.5/t and $942.6/t for CCU-methanol and CCU-DME processes, respectively.

An experimental and modeling study of the application of membrane contactor reactors to methanol synthesis using pure CO2 feeds

We describe here a post-combustion CO2 capture and utilization (CCU) technology that converts the CO2 into methanol (MeOH), a valuable chemical, thus providing a way to monetize the carbon captured to offset process costs. Methanol synthesis (MeS) has been discussed recently for application to CCU, but thermodynamic limitations make it difficult to convert in a single pass a large CO2 fraction. Conventional catalysts show slow kinetics in converting CO2-rich syngas (or pure CO2) into MeOH. Our Group developed (Li and Tsotsis, 2019) a novel MeS process, employing a membrane contactor reactor (MCR) system that attains carbon conversions significantly higher than equilibrium. Our focus here is to process pure CO2 streams by combining the MCR with a separate reactor, which converts the CO2 into a syngas via the reverse water gas shift (RWGS) reaction. In this preliminary effort, the RWGS reactor (RWGSR) is assumed to reach equilibrium. Additional MeS kinetic rate data are generated validating experimentally the ability of the MeS-MCR to process as a feed the RWGSR exit stream. The performance of the combined (RWGSR/MeS-MCR) system is then simulated using a recently developed MeS-MCR model (Zejarbad et al., 2002). The findings are encouraging, and research is currently ongoing to experimentally validate the RWGSR/MeS-MCR system performance.

MgO promoted by Fe2O3 and nitrate molten salt for fast and enhanced CO2 capture: Experimental and DFT investigation

Rapid and strong CO2 capture is critical in CO2 capture and utilization (CCU) techniques to mitigate global warming. Alkali molten salt (AMS) promoted-MgO sorbents with high capacity attracted attention, but their applications suffer from various limitations of low adsorption kinetics and poor stability. Here, AMS-promoted MgO sorbents corporation with Fe2O3 (Mg100-xFex-AMS10) were fabricated via modified methanol evaporation-induced surface precipitation for use in rapid and stable CO2 capture. Based on characterization of the sorbents, Mg98Fe2-AMS10 showed a loose flake structure, with a large surface area and numerous exposed active sites. Therefore, Mg98Fe2-AMS10 exhibited a strong CO2 capacity (14.86 mmolCO2/gsorbent at 300 °C) and good cyclic durability. Three kinetic models were explored, and the Avrami model provided a good prediction of the CO2 adsorption behavior, with Mg98Fe2-AMS10 exhibiting rapid adsorption kinetics. The adsorption mechanism was investigated using density functional theory (DFT) calculations. The charge transfer and bonding strengths of the surface O atoms on MgO increased, and these atoms preferentially bonded with activated CO2 (CO2∙−) under Fe catalysis. This study may provide insights into enhancing the CO2 capture and kinetics of MgO via combination with 3d transition metals.

Turning Waste into Wealth: Sustainable Production of High-Value-Added Chemicals from Catalytic Coupling of Carbon Dioxide and Nitrogenous Small Molecules.

Carbon neutrality is one of the central topics of not only the scientific community but also the majority of human society. The development of highly efficient carbon dioxide (CO2) capture and utilization (CCU) techniques is expected to stimulate routes and concepts to go beyond fossil fuels and provide more economic benefits for a carbon-neutral economy. While various single-carbon (C1) and multi-carbon (C2+) products have been selectively produced to date, the scope of CCU can be further expanded to more valuable chemicals beyond simple carbon species by integration of nitrogenous reactants into CO2 reduction. In this Review, research progress toward sustainable production of high-value-added chemicals (urea, methylamine, ethylamine, formamide, acetamide, and glycine) from catalytic coupling of CO2 and nitrogenous small molecules (NH3, N2, NO3-, and NO2-) is highlighted. C-N bond formation is a key mechanistic step in N-integrated CO2 reduction, so we focus on the possible pathways of C-N coupling starting from the CO2 reduction and nitrogenous small molecules reduction processes as well as the catalytic attributes that enable the C-N coupling. We also propose research directions and prospects in the field, aiming to inspire future investigations and achieve comprehensive improvement of the performance and product scope of C-N coupling systems.

CO2 capture and utilization (CCU) by integrating water electrolysis, electrified reverse water gas shift (E-RWGS) and methanol synthesis

• High temperature E-RWGS enables operation at high pressure. • Electrically heated RWGS reactor simplify methanol synthesis process. • Integration of electrolysis and E-RWGS produces methanol at 90% carbon efficiency. • Biogenic conversion of CO 2 into methanol archives negative emissions.

Solar PV based power-to-methanol via direct CO2 hydrogenation and H2O electrolysis: Techno-economic and environmental assessment

Renewable-power-assisted CO2 capture and utilization (CCU) for methanol synthesis has gained significant attention. This study assesses the techno-enviro-economics of methanol synthesis via CO2 hydrogenation using renewable hydrogen from photovoltaic (PV)-based electrolysis and CO2 originating from natural gas field processing. The study was performed under two scenarios: PV electrolysis with a battery and without a battery, using grid electricity. The proposed process system was simulated using Aspen HYSYS v11. A proton exchange membrane (PEM) electrolyzer was chosen for electrolysis. Methanol synthesis via CO2 hydrogenation was modeled using kinetic models by considering both CO and CO2 as carbon sources. An economic analysis using a levelized cost process and an environmental assessment of CO2-eq emissions were performed. The results show that the overall energy efficiency of integrated hydrogen production and methanol synthesis before and after the heat integration process using a heat exchanger network (HEN) were 48.39% and 55.16%, respectively. From an economic perspective, the methanol production cost was 1040.17 and 1669.56 $/tonne-MeOH for the PV–grid and PV–battery scenarios, respectively. From an environmental perspective, the CO2-eq emissions from the whole process were 0.244 and − 0.016 kg-CO2-eq/MJ-MeOH for the PV–grid and PV–battery scenarios, respectively.

Process design and economic analysis of hydrogen roasting integrated with CCU for a carbon-free spent LIB recycling process

In the lithium-ion battery (LIB) recycling process, the roasting step decomposes the complex cathode material into metal oxides before leaching and precipitation. Hydrogen gas is a potential candidate among various roasting agents because of its rapid roasting time and zero CO2 emission. However, additional flue gas emission is unavoidable on the industrial scale to meet the roasting temperature and further crystallization of the produced LiOH slurry. This study proposed and simulated a carbon-free LIB recycling method via an integrating system of hydrogen roasting and CO2 capture and utilization (CCU) composed of the following processes: hydrogen roasting of cathode material; two-way Li extraction; acid leaching; and selective extraction of remaining metal oxide. In the two-way Li extraction, the LiOH slurry was split and converted into LiOH·H2O(s) and Li2CO3(s) via crystallization and the CCU process, respectively. In the CCU process, the slurry was utilized as a wet CO2 absorbent in the flue gas emitted from the roasting and crystallization process. According to sensitivity analysis, 98.10 % Li recovery with zero CO2 emission was accomplished in a split fraction of 0.26. Furthermore, over 99 % recovery of remaining metal resulted from early Li rejection in the metal oxide mixture. Economic analysis was conducted with a 10,000 ton/year recycling capacity, and the net present value of the proposed system is 2.74E + 09 $, 3.08 % higher than the conventional hydrometallurgy system. The proposed system offers higher Li recovery and feasible economic profit with zero CO2 emission and less chemical waste disposal than the conventional system.

Non-dispersive CO2 separation process using vacuum desorption and ionic liquids as carbon capture and utilization innovative technology

Slowing down climate change requires urgent measures, and consequently, one of the main challenges of the scientific community is to develop innovative technologies to reduce carbon dioxide emissions to the atmosphere. Non-dispersive CO2 absorption using ionic liquids (ILs) as solvent and membrane vacuum regeneration (MVR) as desorption step are considered as a one of the most promising technologies for solvent regeneration in post-combustion CO2 capture and utilization (CCU) since high purity carbon dioxide streams are needed for technical valorization approach. In this work, the chemical binding 1-ethyl-3-methylimidazolium acetate ([emim][Ac]) and the physical solvent 1-ethyl-3-methylimidazolium methyl sulfate ([emim][MS]) have been selected. COSMO based/Aspen Plus methodology has been successfully executed to specify the COSMOSAC property method used in the commercial process simulator (Aspen Plus). Besides, a detailed two-dimensional mathematical model of MVR technology has been validated for the first time with [emim][MS] as a representative of physical ionic liquid solvent. The effect on CO2 desorbed flux and process efficiency have been tested at different operation conditions in order to compare the behavior of chemical and physical absorption based on ionic liquids. Low vacuum pressure and high temperature show a positive influence in the solvent regeneration process, while high liquid flow-rate increases the process performance but also decrease the CO2 desorption. The IL ([emim][Ac]) presented higher MVR performance (92 %) than the IL [emim][MS] (83 %) at the best operational conditions (313 K and 0.04 bar), in which the total energy consumption has been estimated on 0.62 and 0.34 MJe·kgCO2−1, respectively. These results noted the benefit of the MVR technology based on ILs compared to the conventional amino-based high -temperature regeneration process (1.55 MJe·kgCO2−1), presenting a step forward in the substitution of amines. This work provides a valuable tool to help in the decision-making to select the most promising ionic liquids, reducing laboratory efforts and, consequently, experimental costs.