CO2 Capture And Utilization Research Articles

The German Cement Industry as a CO2 Source for Other Industries

Cement production is responsible for about eight percent of global CO2 emissions. A potential use for CO2 is the production of synthetic fuels through power-to-X (PtX) processes. For this purpose, a potential analysis is performed in which the possibilities for CO2 avoidance and CO2 capture and utilization (CCU) in the cement manufacturing process are evaluated. Based on the potential analysis, three scenarios for the development of the German cement industry until 2050 are developed and displayed in geo-referenced form, yielding potential locations for PtX plants. Results show that it is unlikely that cement can be fully replaced by alternative construction methods or new types of binders from today’s perspective. Measures to reduce CO2 emissions in cement production are limited, especially due to the restricted possibilities to replace limestone as feedstock. In an intermediate scenario, CO2 emissions in cement production decrease by 35% until 2050 compared to the average value from the 2014–2018 reference period. For CCU to be introduced at cement plants, the additional costs must be compensated, either through revenues from CO2 certificates or economic and regulatory incentives.

Immobilization of carbonic anhydrase for CO2 capture and utilization.

Carbonic anhydrase (CA) is an excellent candidate for novel biocatalytic processes based on the capture and utilization of CO2. The setup of efficient methods for enzyme immobilization makes CA utilization in continuous bioreactors increasingly attractive and opens up new opportunities for the industrial use of CA. The development of efficient processes for CO2 capture and utilization (CCU) is one of the most challenging targets of modern chemical reaction engineering. In the general frame of CCU processes, the interest in the utilization of immobilized CA as a biocatalyst for augmentation of CO2 reactive absorption has grown consistently over the last decade. The present mini-review surveys and discusses key methodologies for CA immobilization aimed at the development of heterogeneous biocatalysts for CCU. Advantages and drawbacks of covalent attachment on fine granular solids, immobilization as cross-linked enzyme aggregates, and "in vivo" immobilization methods are presented. In particular, criteria for optimal selection of CA-biocatalyst and design of CO2 absorption units are presented and discussed to highlight the most effective solutions. Perspectives on biocatalytic CCU processes that can include the use of CA in an enzymatic reactive CO2 absorption step are eventually presented with a special focus on two examples of CO2 fixation pathways: hybrid enzyme-microalgae process and enzyme cascade for theproduction of carboxylic acids. KEY POINTS: • Covalent immobilization techniques applied to CA are effective for CO2 ERA. • Biocatalyst type and morphology must be selected considering CO2 ERA conditions. • Immobilized CA can offer novel routes to CO2 capture and direct utilization.

Novel process design of desalination wastewater recovery for CO2 and SOX utilization

Desalination is one of the most effective methods of supplying industrial water. Desalination has evolved into a feasible water supply alternative that allows the use of ocean water, and desalination plants operate in many countries, including in arid areas. Therefore, a large amount of desalination wastewater is generated, which is discharged into the sea. Since highly concentrated mineral ions in desalination wastewater are useful substitutes for carbon dioxide (CO2) and sulfur oxide (SOx) utilization compared with limited feedstock, such as high-grade limestone, it is crucial to improve the utilization of metal ions by recovering desalination wastewater. This study presents a novel process of desalination wastewater recovery CO2 and SOx utilization. The proposed process model comprises the following four systems based on validated experimental data: electrolysis, metal ion separation, SOx capture and utilization (SCU), and CO2 capture and utilization (CCU). First, desalination wastewater was electrolyzed to obtain a strong basic solution through electrolysis. Second, during metal ion separation, magnesium and calcium ions in the wastewater were precipitated in the form of a metal hydroxide and separated by the basic solution. Third, the separated Ca(OH)2 was used for desulfurization and produced gypsum in the SCU system. Finally, CO2 in the desulfurized flue gas was captured by the strong basic solution and utilized as CaCO3 and MgCO3 in the CCU procedures. Consequently, about 91% CO2 is captured and utilized from flue gas, and the desulfurization efficiency is 99%. In addition, the maximum net profit of the proposed process is $ 73.23 per tonne of CO2, and it is profitable and suitable for large-capacity processes, compared with other alternative CCU processes.

Integrated carbon capture and utilization to methanol with epoxide-functionalized polyamines under homogeneous catalytic conditions

Herein, a novel amine based integrated process is presented for CO2 capture and utilization (CCU) to synthesize methanol. Reaction of pentaethylenehexamine (PEHA) with selected epoxides led to a library of functionalized polyamines. In aqueous medium, the modified amines were efficient in capturing CO2 under ambient conditions. Subsequently, the CO2 loaded solutions were directly subjected to catalytic hydrogenation to CH3OH in presence of molecular H2 and Ru-PNP based molecular catalysts. While the epoxide-modified amines exhibited CO2 capture efficiencies comparable to those of unmodified PEHA, they displayed a notable enhancement in the hydrogenation step resulting in higher methanol yields of up to 93%. Furthermore, the integrated process was demonstrated in a water and 2-methyl-THF based biphasic solvent system. We believe that the improved amine-based system for CO2 capture and hydrogenation to methanol is key in advancing low temperature and renewable methanol synthesis processes.

An integrated CCU-plant scheme and assessment for conversion of captured CO2 into methanol

Abstract The purpose of this work is to highlight the interest of CO2 conversion into MeOH through a complete assessment of the entire CO2-to-MeOH chain. A CO2 capture unit using MEA solvent is considered to treat the CO2 from a 600-MW power plant, and the captured CO2 is then sent to the CO2 conversion unit. As a result, the combination of the two units leads to the integrated CO2 capture and utilization (CCU) plant, in particular involving the reuse of the heat from the high-temperature flows of the exothermal CO2 conversion reactions for regeneration of the CO2 capture solvent, and the recovered H2O between the CO2 capture and conversion units is also proposed to completely fulfill the H2O make-up. The technological results suggest that the integrated CCU plant is expected to offer advantages. The integrated CCU plant studied can utilize ~17.3% of the CO2 emissions of a power plant and convert 92% of them to 59.96 t of MeOH, and the heat integration corresponds to a 41.84% reduction in total reboiler load for the regeneration of MEA solvent. An economic assessment is proposed to estimate the OPEX and CAPEX costs, as well as the net present value, which confirms that the feasible economic conditions strongly depends on electricity costs. The contribution of the process or flows from CCU plant to the main environmental impacts is finally determined using the LCA method. The integrations inside the CCU plant offer a significant reduction in impact categories and CO2 emission as well as non-CO2 emission impacts when compared to the conventional MeOH production process.

A State‐of‐the‐Art Update on Integrated CO2 Capture and Electrochemical Conversion Systems

AbstractTo valorize waste CO2, capturing and utilizing it to produce chemical building blocks is currently receiving a lot of attention. In this respect, amine and alkali base solutions have shown to be efficient CO2 capturing solutions and electrochemical CO2 conversion is a promising technology to convert CO2 and, as such, reduce greenhouse gas emissions. However, to date, CO2 capture and utilization (CCU) technologies have been investigated almost exclusively as separate processes. This has the disadvantage that CO2 has to be desorbed and compressed from the capture solution before sending it to the CO2 electrolyzer, seriously increasing the capital and operational costs of the overall technology. To improve the valorization potential of the CCU technologies, integrating both technologies by directly utilizing the capture solution as an electrolyte for the electrochemical CO2 reduction (eCO2R) is a highly promising approach. This technology is however limited by low Faradaic efficiencies (FE) and partial current densities that can be achieved with these solutions. The main reason for this is the slow CO2 release rate at the catalytic interphase. Nevertheless, in recent years, in light of tackling these challenges, several studies successfully managed to decrease the costs of the CO2 capturing step and to electrochemically convert more efficiently the CO2 capture solutions. Herein, we review the status of the integrated CO2 capture and electrochemical conversion technology, discussing the recent developments and advances both in the field of CO2 capture and eCO2R.

Sustainable Membrane-Based Wastewater Reclamation Employing CO2 to Impede an Ionic Precipitation and Consequent Scale Progression onto the Membrane Surfaces.

CO2 capture and utilization (CCU) is a promising approach in controlling the global discharge of greenhouse gases (GHG). This study details the experimental investigation of CO2 utilization in membrane-based water treatment systems for lowering the potential of ionic precipitation on membrane surface and subsequent scale development. The CO2 utilization in feed water reduces the water pH that enables the dissociation of salts in their respective ions, which leave the system as a concentrate. This study compares the efficiency of CO2 and other antifouling agents (CA-1, CA-2, and CA-3) for fouling control in four different membrane-based wastewater reclamation operations. These systems include Schemes 1, 2, 3, and 4, which were operated with CA-1, CA-2, CA-3, and CO2 as antiscalants, respectively. The flux profile and percent salt rejection achieved in Scheme 4 confirmed the higher efficiency of CO2 utilization compared with other antifouling agents. This proficient role of CO2 in fouling inhibition is further endorsed by the surface analysis of used membranes. The SEM, EDS, and XRD examination confirmed the higher suitability of CO2 utilization in controlling scale deposition compared with other antiscalants. The cost estimation also supported the CO2 utilization for environmental friendly and safe operation.

Close-cycle process to produce CO2-derived propylene carbonate based on amino acid catalyst and water

CO2 Capture and Utilization (CCU) strategy is being investigated trying to mitigate CO2 emissions and producing value-added compounds. Specifically, CO2 conversion to cyclic carbonates using ionic liquids (ILs) is being studied as alternative due to the high yields obtained. The challenge to design a CO2 conversion process based on ILs is to efficiently and sustainably solve the product/catalyst separation, especially dealing with a homogeneous catalytic step. In this work, we report the use of ILs based on amino acids as catalysts in combination with water to achieve the reaction mixture separation, enhance the catalytic activity and increase the sustainability of the process. The total catalyst recovery and the product purification were achieved by means of liquid-liquid extraction using water as extracting agent, reaching remarkable distribution coefficients and selectivities. Moreover, the presence of water in the reaction stage increases in more than 40 % the conversion values. In the light of these individual impacts, it is proposed a sustainable process to efficiently produce cyclic carbonates in mild conditions, successfully modelled by COSMO/Aspen methodology. This work presents as first time a feasible CO2 conversion to cyclic carbonates process by addressing the separation of the catalyst from the reaction products with compatibleness with the reaction step, even enhancing catalytic activity, and avoiding high energy-demanding technologies.

Integrating life cycle assessment for design and optimization of methanol production from combining methane dry reforming and partial oxidation

CO2 capture and utilization (CCU) is a potential solution for combating global warming potential. Utilization of CO2 as a renewable raw material for producing methanol has been intensively investigated. Nevertheless, the benefits of CO2 utilization cannot be guaranteed unless the entire production process is rigorously evaluated and optimized. This study attempts to minimize CO2 emissions of the methanol production process via the synthesis of intermediate syngas using the dry methane reforming (DR) method in combination with the partial oxidation (PO) of methane. We noted that the contributions from DR and PO to the overall reaction process depended on the input raw material ratios. Marked differences in desired operating conditions were noted when maximizing syngas and methanol yields, thereby making process optimization difficult. Herein, to find the optimal operating conditions for minimizing overall CO2 emissions, effective process design and simulation, and the cradle-to-gate life cycle assessment (LCA) were integrated. Process CO2 emissions, including those from all sources of indirect and direct CO2 emissions from raw materials, utility production processes, and “end-of-pipe” waste treatment option were evaluated based on noted variations in the identified key variables. Suitable operating conditions for reducing the total process CO2 emissions were proposed. Although the current study results in low level of CO2 utilization, it attains a low CO2 emissions process for producing methanol via syngas (i.e., 0.81 kg CO2/kg methanol). The results obtained herein highlight the significance of implementing LCA method using suitable evaluation boundary to design environmentally friendly CO2 utilization processes.

An amino acid based system for CO2 capture and catalytic utilization to produce formates.

Herein, we report a novel amino acid based reaction system for CO2 capture and utilization (CCU) to produce formates in the presence of the naturally occurring amino acid l-lysine. Utilizing a specific ruthenium-based catalyst system, hydrogenation of absorbed carbon dioxide occurs with high activity and excellent productivity. Noteworthy, following the CCU concept, CO2 can be captured from ambient air in the form of carbamates and converted directly to formates in one-pot (TON > 50 000). This protocol opens new potential for transforming captured CO2 from ambient air to C1-related products.

Comparison of Various Electrode Fabrication Methods for Use in an Electrolyzer to Produce of HCl and NaOH from NaCl

Many researches on CO2 capture and utilization (CCU) are being actively pursued to suppress its global warming effects and to utilize CO2 as a feedstock for producing useful organic and inorganic substances such as methanol, formic acid, and carbonates through biological, thermal, photochemical and electrochemical methods.This study focuses on the fabrication methods of anodes for use in an electrolyzer to produce alkali (NaOH) and hydrochloric acid (HCl) by splitting a brine (aqueous NaCl) that would be used to convert carbon dioxide into carbonate minerals at a subsequent stage. The electrolyzer consists of an anode, a membrane 1, a middle plate, a membrane 2 and a cathode. A hydrogen gas is supplied to the anode compartment, a dilute NaOH aqueous solution is to the cathode, and a feed solution of NaCl is to the middle plate. The membranes can be both cationic ones. Upon applying a voltage of around 1.5V, HCl is produced at the anode, and NaOH is produced at the cathode.This study is focused on the fabrication methods to make active and durable anodes. The anode is usually made of Pt particles dispersed on porous and electrically conductive substrates. The fabrication methods can be appropriately chosen depending on the types of substrates. In this study, two types of substrates were used, carbon cloth and carbon paper. In case of using a carbon cloth as substrate, two types of fabrication methods were used, a spraying method and a screen printing method while in case of using a carbon paper an electroplating method was used. When using a spraying method, an appropriate amount Pt/C catalyst powder was dispersed in an aqueous isopropyl alcohol(IPA) solution containing a given amount of Nafion ionomer to make a catalyst ink. The catalyst ink was sprayed on a carbon cloth using a nitrogen spray gun to make an anode consisting a Pt-catalyst coated a carbon cloth having a thickness of 0.45 mm. After drying in an oven, it was used as anode for the electrolyzer. In the case of screen printing method, a viscous catalyst slurry was made by mixing an appropriate amount of catalyst powder, IPA, Nafion ionomer and glycerin, which was then spread on the surface of a carbon cloth (CC) using a silk screen having a proper mesh size. The resulting slurry-coated CC was put in a vacuum oven at 150oC to remove the glycerin, followed by a pretreatment step to swell the dried ionomer in the catalyst layer. The Pt loading was 0.30 mg/cm2. The electroplating method was used to plate Pt on the surface of a carbon paper (CP) having a thickness of 0.20mm. The CP was first pre-treated in a H2SO4 solution and then immersed in a plating solution consisting of H2PtCl6 in a 0.5M solution. Electroplating of Pt was carried out by applying a current of 20 mA/cm2 to deposit 0.30mg-Pt/cm2.Those fabricated anodes were installed in an electrolyzer cell using Nafion 115 as membrane 1 and 2 and a Ni mesh electrode as cathode. The cell performance was measured by supplying H2 into the anode side and a dilute NaOH solution into the cathode side while applying a voltage of 1.5V to the cell. As shown in the figure, the cell performances vary depending on the anode fabrication methods, indicating the structure of anode affects the cell performance. Therefore, in order to improve the performance of the anodes, various fabrication factors need to be optimized to make the structure of the catalyst layer suitable for the reaction. Figure 1

CO2 Desorption Performance from Imidazolium Ionic Liquids by Membrane Vacuum Regeneration Technology.

In this work, the membrane vacuum regeneration (MVR) process was considered as a promising technology for solvent regeneration in post-combustion CO2 capture and utilization (CCU) since high purity CO2 is needed for a technical valorization approach. First, a desorption test by MVR using polypropylene hollow fiber membrane contactor (PP-HFMC) was carried out in order to evaluate the behavior of physical and physico-chemical absorbents in terms of CO2 solubility and regeneration efficiency. The ionic liquid 1-ethyl-3-methylimidazolium acetate, [emim][Ac], was presented as a suitable alternative to conventional amine-based absorbents. Then, a rigorous two-dimensional mathematical model of the MVR process in a HFMC was developed based on a pseudo-steady-state to understand the influence of the solvent regeneration process in the absorption–desorption process. CO2 absorption–desorption experiments in PP-HFMC at different operating conditions for desorption, varying vacuum pressure and temperature, were used for model validation. Results showed that MVR efficiency increased from 3% at room temperature and 500 mbar to 95% at 310 K and 40 mbar vacuum. Moreover, model deviation studies were carried out using sensitivity analysis of Henry’s constant and pre-exponential factor of chemical interaction, thus as to contribute to the knowledge in further works.

Reduced Graphene Oxide Supported Ag Nanoparticles: An Efficient Catalyst for CO2 Conversion at Ambient Conditions

AbstractA highly efficient carboxylative cyclization of propargylic alcohols with CO2 under atmospheric pressure catalyzed by silver (0) nanoparticles decorated reduced graphene oxide (Ag‐rGO) is reported. Ag‐rGO was fully characterized by scanning electron microscope spectra (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR) spectra, Raman spectra and X‐ray photoelectron spectroscopy (XPS). Notably, Ag‐rGO can be also applied to the construction of other value‐added chemicals (β‐oxopropylcarbamates and 2‐oxazolidinones) from CO2 at ambient conditions. In addition, Ag‐rGO is stable and reusable, which shows the potential for the practical application for CO2 capture and utilization (CCU).

Carbon recycling – An immense resource and key to a smart climate engineering: A survey of technologies, cost and impurity impact

In order to meet climate goals, both CO2 capture and storage (CCS) and CO2 capture and utilization (CCU) have been identified as increasingly important technologies for mitigating CO2 emissions that are difficult to avoid. In this work, the CO2 utilization, or more specifically, the CO2 conversion to fuels and urea, considering the large demand for CO2, as well as the CO2 mineralization are surveyed and reviewed. The content of this review includes technologies – all the way from the laboratory studies to the industrial applications – their current status, and future potential. CCS is included for a comparison concerning the costs. Also, aspects as the CO2 impurities and the effect of it as well as various requirements concerning the CO2 impurity are included. Many recent studies show that CCU, especially CO2 conversion to fuels, will play an essential role in mitigating CO2 emissions, while developed methods and technologies are not yet mature. More research work needs to be conducted to improve the process efficiency via developing catalysts and reducing the cost of producing H2 that is used as a reactant for fuel synthesis. Moreover, current literature also shows that impurities will affect the process of both CCS and CCU, while the work of studying their influence, especially on CCU, is still scarce. The cost of CCS has been estimated combined with impurities, while studies on cost estimation for CCU are still limited, and the cost, in general, is relatively high with the currently available technologies.

Eliminating carbon dioxide emissions at the source by the integration of carbon dioxide capture and utilization over noble metals in the liquid phase

Carbon dioxide (CO2) capture and utilization (CCU) offer a response to greenhouse gas emissions whereas they are often conducted separately, resulting in a high energy demand for the CO2 separation process. The capture reagent chemically binds the CO2 molecule, activating the stubborn CO2 to a more active species. The direct conversion of the captured and activated CO2 to the value-added chemicals will simplify the CO2 utilization process, leading to a strong energy-saving effect by omitting the CO2 separation process. In this paper, the commercial and the self-synthesized noble metal catalysts were evaluated in the hydrogenation of amine captured CO2 in ethanol at 140–165 °C, which is demonstrated to produce the main product methanol in the presence of K3PO4 or using MgO as a catalyst support. The Pd-based catalyst was superior to the Rh, Pt or Ru based catalyst in the hydrogenation of amine captured CO2 towards methanol. The superior Pd/MgO catalyst was characterized by XRD, XPS, SEM, HRTEM, and DRIFTS analysis. NMR measurement and the ATR FTIR measurements were used to determine the initial intermediate to be ethyl carbonate. Mechanistic insight to the methanol formation indicates that the synergistic effect of Pd and a base cascaded the reactions: the reduction of ethyl carbonate to formic acid, the dehydration between formic acid and ethanol to form ethyl formate, and the hydrogenolysis of ethyl formate to methanol and ethanol. The ethyl formate intermediate was hydrogenated to methanol by Pd, wherein basic condition (K3PO4 or MgO) was responsible for the activation of the carbonyl group of the ethyl formate.

Concentrated Carbon Dioxide (CO2) from Diluted Sources through Continuous Temperature Swing Adsorption (TSA)

Carbon dioxide (CO2) capture and storage (CCS) and most CO2 capture and utilization (CCU) routes require concentrated CO2 streams for efficient compression, pipeline transport, injection, or chemic...

Integration of Membrane Separation with Nonthermal Plasma Catalysis: A Proof-of-Concept for CO2 Capture and Utilization

Carbon dioxide (CO2) capture and utilization (CCU) plays an important role in abating carbon emissions, mitigating global warming, and converting CO2 as feedstock to value-added fuels and chemicals...

Efficient One Pot Capture and Conversion of CO2 into Quinazoline-2,4(1H,3H)-diones Using Triazolium-Based Ionic Liquids

CO2 capture and utilization (CCU) have aroused much attention. In this paper, several novel triazolium-based ionic liquids (ILs) were developed for highly efficient transformation of CO2 into quina...

Industrial carbon dioxide capture and utilization: state of the art and future challenges.

Dramatically increased CO2 concentration from several point sources is perceived to cause severe greenhouse effect towards the serious ongoing global warming with associated climate destabilization, inducing undesirable natural calamities, melting of glaciers, and extreme weather patterns. CO2 capture and utilization (CCU) has received tremendous attention due to its significant role in intensifying global warming. Considering the lack of a timely review on the state-of-the-art progress of promising CCU techniques, developing an appropriate and prompt summary of such advanced techniques with a comprehensive understanding is necessary. Thus, it is imperative to provide a timely review, given the fast growth of sophisticated CO2 capture and utilization materials and their implementation. In this work, we critically summarized and comprehensively reviewed the characteristics and performance of both liquid and solid CO2 adsorbents with possible schemes for the improvement of their CO2 capture ability and advances in CO2 utilization. Their industrial applications in pre- and post-combustion CO2 capture as well as utilization were systematically discussed and compared. With our great effort, this review would be of significant importance for academic researchers for obtaining an overall understanding of the current developments and future trends of CCU. This work is bound to benefit researchers in fields relating to CCU and facilitate the progress of significant breakthroughs in both fundamental research and commercial applications to deliver perspective views for future scientific and industrial advances in CCU.

Characterization and High-Level Periplasmic Expression of Thermostable α-Carbonic Anhydrase from Thermosulfurimonas Dismutans in Escherichia Coli for CO2 Capture and Utilization.

Carbonic anhydrase (CA) is a diffusion-controlled enzyme that rapidly catalyzes carbon dioxide (CO2) hydration. CA has been considered as a powerful and green catalyst for bioinspired CO2 capture and utilization (CCU). For successful industrial applications, it is necessary to expand the pool of thermostable CAs to meet the stability requirement under various operational conditions. In addition, high-level expression of thermostable CA is desirable for the economical production of the enzyme. In this study, a thermostable CA (tdCA) of Thermosulfurimonas dismutans isolated from a deep-sea hydrothermal vent was expressed in Escherichia coli and characterized in terms of expression level, solubility, activity and stability. tdCA showed higher solubility, activity, and stability compared to those of CA from Thermovibrio ammonificans, one of the most thermostable CAs, under low-salt aqueous conditions. tdCA was engineered for high-level expression by the introduction of a point mutation and periplasmic expression via the Sec-dependent pathway. The combined strategy resulted in a variant showing at least an 8.3-fold higher expression level compared to that of wild-type tdCA. The E. coli cells with the periplasmic tdCA variant were also investigated as an ultra-efficient whole-cell biocatalyst. The engineered bacterium displayed an 11.9-fold higher activity compared to that of the recently reported system with a halophilic CA. Collectively these results demonstrate that the highly expressed periplasmic tdCA variant, either in an isolated form or within a whole-cell platform, is a promising biocatalyst with high activity and stability for CCU applications.