Semi-batch Reactor Research Articles

Safe Operating Conditions of isoperiodic Homogeneous Semi-Batch Reaction Based on Parameter Uncertainties Analysis

Proper operating conditions have a significant impact on the process state of semi-batch reaction. However, various error and bias lead to the uncertainties of parameter, which affect process safety of the semi-batch reaction. In this work, the effect of dimensionless parameters dimensionless adiabatic temperature rise (), Westerterp number (Wt), , dimensionless activation energy (γ), volumetric heat capacity ratio (RH) and relative volume increase (ε) on the temperature of the isoperiodic homogeneous semi-batch reaction are investigated by local sensitivity analysis. The sensitivity of the dimensionless maximum temperature to global parameters is analyzed using the scatter plot method based on Monte-Carlo sampling. Parameter sensitivity results are further quantitatively calculated by the eFAST method. The results indicate that there is a strong linear relationship between the maximum reaction temperature and △τad,0, which exhibits the highest sensitivity index compared to the other parameters. The safety boundary diagram and adiabatic temperature diagram are constructed by considering parameter uncertainty and the effect of parameter uncertainty on the critical criteria is analyzed.

Method for predicting the size of Ni1/3Mn1/3Co1/3(OH)2 particles precipitated in a stirred-tank semi-batch crystallizer using CFD and particle agglomeration models

NixMnyCoz(OH)2 is widely used as a precursor for the cathode active material LiNixMnyCozO2 in lithium ion batteries, and the precursor size, which determines the size of the active cathode material, affects the characteristics of lithium-ion batteries. This paper proposes a method for predicting the particle size of Ni1/3Mn1/3Co1/3(OH)2 precipitated by semi-batch reaction crystallization. The distribution of supersaturated components formed in the reactor varies with the reactor scale, feed conditions of the raw material solution, and agitation conditions. Therefore, the method presented in this paper considers the effects of these conditions on particle growth. First, to identify the turbulent dispersion and concentration distribution of the supersaturated components formed in the reaction crystallizer, a computational fluid dynamics (CFD) model was constructed consisting of the governing equations of hydrodynamics and the mass balance equations of the supersaturated components considering the production by neutralization and consumption by precipitation. Next, a model of agglomeration was constructed that focused on the balance of the binding and breaking up energies for the particle pairs. The binding energy was quantified based on the bridging between particle pairs by surface deposition. The breaking up-energy was quantified based on the hydrodynamic forces when the agglomerate passes through the impeller. These models were fitted using experimental results for the final average size of the Ni1/3Mn1/3Co1/3(OH)2 secondary aggregate, which was precipitated in a small-scale stirred-tank type semi-batch reaction crystallizer. The models predicted the experimental results of the final average size in a large-scale crystallizer, with the feeding conditions of the raw material solution and stirring conditions as experimental parameters, within ±20%. The models may be used to analyze semi-batch reaction crystallization systems of NixMnyCoz(OH)2 of any composition by adjusting the model parameters according to the procedure developed in this study.

Anaerobic digestion of wastewater from hydrothermal liquefaction of sewage sludge and combined wheat straw-manure

Hydrothermal liquefaction (HTL) shows promise for converting wet biomass waste into biofuel, but the resulting high-strength process water (PW) requires treatment. This study explored enhancing energy recovery by anaerobic digestion using semi-batch reactors. Co-digesting manure with HTL-PW from wheat straw-manure co-HTL yielded methane (43–49% of the chemical oxygen demand, COD) at concentrations up to 17.8 gCOD·L-1, whereas HTL-PW from sewage sludge yielded methane (43% of the COD) up to only 12.8 gCOD·L-1 and complete inhibition occurred at 17 gCOD·L-1. Microbial community shifts confirmed inhibition of methanogenic archaea, while hydrolytic-fermentative bacteria were resilient. Differences in chemical composition, particularly higher levels of N-containing heterocyclic compounds in PW of sewage sludge, likely caused the microbial inhibition. The considerable potential of combining HTL with anaerobic digestion for enhanced energy recovery from straw-manure in an agricultural context is demonstrated, yet sewage sludge HTL-PW requires more advanced approaches to deal with methanogenesis inhibitors.

Data-Based Modeling, Multi-Objective Optimization and Multi-Criteria Decision Making of a Catalytic Ozonation Process for Degradation of a Colored Effluent

In the catalytic ozonation process (COP), the reactions are complex, and it is very difficult to determine the effect of different operating parameters on the degradation rate of pollutants. Data-based modeling tools, such as the multilayer perceptron (MLP) neural network, can be useful in establishing the complex relationship of degradation efficiency with the operating variables. In this work, the COP of acid red 88 (AR88) with Fe3O4 nano catalyst was investigated in a semi-batch reactor and a MLP model was developed to predict the degradation efficiency (%DE) of AR88 in the range of 25 to 96%. The MLP model was trained using 78 experimental data having five input variables, namely, AR88 initial concentration, catalyst concentration, pH, inlet air flow rate and batch time (in the ranges of 150–400 mg L−1, 0.04–0.4 g L−1, 4.5–8.5, 0.5–1.90 mg min−1 and 5–30 min, respectively). Its optimal topology was obtained by changing the number of neurons in the hidden layer, the momentum and the learning rates to 7, 0.075 and 0.025, respectively. A high correlation coefficient (R2 > 0.98) was found between the experimental and predicted values by the MLP model. Simultaneous maximization of %DE and minimization of Fe3O4 concentration was carried out by multi-objective particle swarm optimization (MOPSO) and the Pareto-optimal solutions were successfully obtained. The trade-off was analyzed through multi-criteria decision making, and one Pareto-optimal solution was selected. The developed model and optimal points are useful for treatment of AR88 wastewater.

Depolymerization of PMMA-Based Dental Resin Scraps on Different Production Scales

This research explores the depolymerization of waste polymethyl methacrylate (PMMAW) from dental material in fixed bed semi-batch reactors, focusing on three production scales: laboratory, technical and pilot. The study investigates the thermal degradation mechanism and kinetics of PMMAW through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, revealing a two-step degradation process. The heat flow during PMMAW decomposition is measured by DSC, providing essential parameters for designing pyrolysis processes. The results demonstrate the potential of DSC for energetic analysis and process design, with attention to standardization challenges. Material balance analysis across the production scales reveals a temperature gradient across the fixed bed negatively impacting liquid yield and methyl methacrylate (MMA) concentration. Reactor load and power load variables are introduced, demonstrating decreased temperature with increased process scale. The study identifies the influence of temperature on MMA concentration in the liquid fraction, emphasizing the importance of controlling temperature for efficient depolymerization. Furthermore, the research highlights the formation of aromatic hydrocarbons from the remaining char, indicating a shift in liquid composition during the depolymerization process. The study concludes that lower temperatures below 450 °C favor liquid fractions rich in MMA, suggesting the benefits of lower temperatures and slower heating rates in semi-batch depolymerization. The findings contribute to a novel approach for analyzing pyrolysis processes, emphasizing reactor design and economic considerations for recycling viability. Future research aims to refine and standardize the analysis and design protocols for pyrolysis and similar processes.

Pressure Behaviors and Isothermal Kinetics of Magnesiothermic Reduction of Titanium Tetrachloride in a Semi-batch Reactor

Pressure Behaviors and Isothermal Kinetics of Magnesiothermic Reduction of Titanium Tetrachloride in a Semi-batch Reactor

Synthesis/separation of 5-hydroxymethylfurfural converted from fructose promoted by H2O–CO2 biphasic system with solid catalysts: Experimental and kinetic modeling approaches

5-Hydroxymethylfurfural (5-HMF) is an industrially valuable compound typically produced by dehydration of fructose converted from cellulosic biomass. However, the formation of 5-HMF is accompanied by its conversion into by-products, such as levulinic and formic acids, decreasing its yield. Therefore, biphasic processes are attracting much attention allowing the efficient simultaneous synthesis and separation of 5-HMF. In this study, a biphasic system using water with high-pressure carbon dioxide, the most environmentally friendly solvents, combining with a solid catalyst is used to achieve 5-HMF synthesis and separation at lower temperatures and shorter duration than previous studies. The main experiment was operated by a semibatch reactor with a continuous flow of CO2. Additionally, three experiments, i) measurement of the partition coefficient of 5-HMF between the two phases, ii) 5-HMF synthesis in H2O–CO2 biphasic batch system, and iii) 5-HMF extraction in H2O–CO2 biphasic semibatch system, were conducted to complement the main experiment. All results from complement experiments were used as parameters in the kinetic modeling. As the result, the maximum yield of 5-HMF (36.6 %) was achieved at a temperature of 403 K, a pressure of 25 MPa, and a reaction time of 180 min. Finally, the optimal conditions for the semibatch experiment for 5-HMF synthesis and separation could be estimated from the kinetic models with parameters determined in this work. The obtained results suggested that this yield can be further improved by increasing the reaction time, which should be confirmed by further experimental studies.

Population Balance Equations for Reactive Separation in Polymer Upcycling.

Many polymer upcycling efforts aim to convert plastic waste into high-value liquid hydrocarbons. However, the subsequent cleavage of middle distillates to light gases can be problematic. The reactor often contains a vapor phase (light gases and middle distillates) and a liquid phase (molten polymers and waxes with a suspended or dissolved catalyst). Because the catalyst resides in the liquid phase, middle distillates that partition into the vapor phase are protected against further cleavage into light gases. In this paper, we consider a simple reactive separation strategy, in which a gas outflow removes the volatile products as they form. We combine vapor-liquid equilibrium models and population balance equations (PBEs) to describe polymer upcycling in a two-phase semibatch reactor. The results suggest that the temperature, headspace volume, and flow rate of the reactor can be used to tune selectivity toward the middle distillates, in addition to the molecular mechanism of catalysis. We anticipate that two-phase reactor models will be important in many polymer upcycling processes and that reactive separation strategies will provide ways to boost the yield of the desired products in these cases.

Photon Density Wave spectroscopy to monitor the particle size in seeded semibatch emulsion copolymerization reactions

The performance of Photon Density Wave spectroscopy (PDW) is assessed to inline monitor the particle size during the seeded semibatch emulsion copolymerizations of methyl methacrylate, butyl acrylate, methacrylic acid (MMA/BA/MAA = 51/47/2 wt% composition) with particle size and solids content ranges relevant in industrial formulations. Moreover, the suitability of the technique to early detect some of the most probable deviations, such as particle aggregation and secondary nucleation, is studied. It is shown that the PDW can be successfully used to inline monitor the reduced scattering coefficient, and consequently the particle size evolution in emulsion polymerization reactions for a broad range of particle sizes and solids contents. Nevertheless, for particle sizes higher than 350 nm and solids content above 40 %, the low signal to noise ratio together with the characteristic multiple solutions regime of the theoretical reduced scattering versus the particle size curve, produces uncertainties in the determination of the particle size by PDW.

Deactivation by coking of industrial ZSM-5 catalysts used in LDPE pyrolysis and regeneration by ozonation process – Bench scale studies

Study of the catalytic deactivation during successive uses of ZSM-5 catalysts in bench-scale pyrolysis of low-density polyethylene (200:20 g LDPE:ZSM-5) has been carried out in a semi-batch reactor at 450 °C. The correlation between coke formation over catalyst properties and selectivity during pyrolysis is observed. The loss of catalytic performances translates into a significant drop of aromatics and an increase of waxes in pyrolysis products. The observed deactivation is due to the formation of heavy coke over the catalysts, causing surface hindering, porosity blockage and acid sites diminution. The capacity of ozonation process to regenerate such coked catalysts around 100 °C is demonstrated using a fixed bed reactor. Different times of exposure are investigated to evaluate ozonation efficiency. By using this coke oxidizing treatment during 48 h, regenerated catalysts recovered their initial textural and chemical characteristics (porous volume and acidity) as well as their catalytic performances (similar aromatics proportion as the first pyrolysis).

Synthesis of LaNiCeO2 Mixed Oxide with Various Microcrystalline Cellulose Templated for Deoxygenation of Waste Cooking Oil

The synthesis of LaNiCeO2 mixed oxides utilizing varying proportions of microcrystalline cellulose (MCC) (12.5%, 25%, and 37.5%) has been successfully achieved. The resulting materials were characterized through XRD, FESEM, N2 adsorption-desorption isotherms, and TGA- DTG. XRD analysis confirmed that all synthesized LaNiCeO2 mixed oxides exhibited a stable CeO2 phase. Notably, increasing the MCC content led to an improvement in the catalysts’ pore volume and surface area, with the LaNiCeO2-12.5% MCC sample exhibiting a primarily mesoporous structure and minimal micropore contribution. The LaNiCeO2-25% MCC catalyst demonstrated optimal physicochemical properties, indicating its high suitability for catalytic applications. The catalytic deoxygenation of waste cooking oil (WCO) was carried out in a semi-batch reactor at 380 °C for a duration of 4 hours, with a catalyst loading set at 1% of the WCO’s weight. The LaNiCeO2-12.5% MCC catalyst exhibited exceptional deoxygenation activity, achieving a 100% conversion, a liquid product yield of 45%, and hydrocarbon selectivity of 98%. The excellent catalytic performance is due to the synergistic interaction between Ni, Ce, and La metals, combined with improved properties that promote the deoxygenation reaction. These results highlight the potential of LaNiCeO2 as an effective catalyst for biofuel production.

GBL/BDO pair as a bio-based liquid organic carrier: Kinetic modeling of liquid phase hydrogenation and dehydrogenation over copper-based catalyst

The use of liquid organic hydrogen carriers (LOHC) for hydrogen storage has technical, economical, and environmental advantages. The γ-butyrolactone (GBL)/1,4-butanediol (BDO) pair is used in this work as a bio-based LOHC. Reaction kinetics of liquid phase GBL hydrogenation and BDO dehydrogenation have been studied using a semi-batch reactor filled with a copper based methanol catalyst with the experiments have been performed in the temperature range of 458–503 K with a constant pressure of 50 and 3 bar for hydrogenation and dehydrogenation respectively. Based on analytical results, a reaction pathway including the formation of side products was proposed. This pathway includes the formation of two side-products: 4-hydroxybutyl 4-hydroxybutanoate (4-HHB) is produced from the transesterification of GBL by BDO in both reactions; and dibutyleneglycol (DG) from the etherification of BDO in dehydrogenation. Based on experimental results, kinetic models were established for hydrogenation and dehydrogenation reactions. In these models, balanced reactions with a first order were used. Estimation of kinetic parameters for both reactions allows a good prediction of the experimental data and results in a temperature extrapolation by an Arrhenius law. Activation energies for GBL hydrogenation and BDO dehydrogenation were determined to be respectively 104 kJ/molLOHC and 98.3 kJ/molLOHC. Furthermore, models are valid at short (up to 5 h) and long (up to 20 h) reaction times and the estimation results display acceptable uncertainties for all the reaction temperatures.

Production of boric acid from colemanite ore in the semi-batch reactor: Investigation of product yield and impurity control

Boric acid is produced by the reaction between colemanite ore and sulfuric acid in industrial processes. Since colemanite ore is not pure, various side reactions, including partial clay decomposition, can occur in the reactor medium. These reactions also lead to the presence of impurities, specifically sulfate salts. In this context, semi-batch reactors (SBR) provide selectivity, and the rate of side reactions is reduced. However, batch reactors (BR) and continuous stirred tank reactors (CSTR) have been used for boric acid production both on an industrial scale and on a laboratory scale, and the semi-batch reactor has never been used for this area. This study used SBR to minimize the side reactions rate and impurities for boric acid production. In the experimental process, a specific concentration of sulfuric acid solution was fed to the reactor at varying flow rates. The yield in the SBR increased up to 99.6%, depending on the sulfuric acid feed rate. When the same conditions were applied in the BR experiment, the yield was calculated to be 90.8%. Compared with the batch reactor results, it was observed that the impurity concentration in the boric acid solution produced within the SBR decreased by 41.7% to 45.3%, depending on the feed rate. Consequently, the utilization of SBR demonstrated clear advantages over the BR in terms of both yield and impurity control. Furthermore, this study serves as a compelling illustration of the practical applications of solid–liquid heterogeneous phase reactions within the context of SBR technology.

Pengaruh Pre-Treatment Kimia dan Biologi Terhadap Produksi Biogas dari Kulit Kopi

Coffee, as a major commodity in Indonesia, produces a huge number of byproducts and residues during the processing process. Coffee wastes and byproducts produced during coffee berry processing are a major source of contamination and represent significant environmental challenges in the coffee production process. One promising alternative in utilizing coffee wastes is converting into energy source i.e, of biogas from coffee pulp. Coffee pulp has toxic components that act as a methane inhibitor; these type of biomass have a problem with the lignin degradation process, which binds cellulose and hemicellulose. The use of cow's rumen fluid for methane production from coffee pulp is still rare, particularly for rumen fluid. Chemical pretreatment was carried out using alkali-peroxide followed by rumen fluid pretreatment. The performance of biogas produced from coffee pulp (with and without pretreatment) using rumen fluid as an inoculum has been investigated. Biogas was produced in a semi-batch reactor with a working volume of 2 liters for 30 days. Removal lignin, SS, VFA, and biogas yield were measured. This study aims to determine the biogas production from coffee pulp using variation HRT 20 and 30 days. It can be concluded that chemical pretreatment of NaOH - H2O2 combination can reduce lignin up to 75.02%. The volume of biogas produced increased with chemical pretreatment and rumen fluid as compared to the substrate with only rumen pretreatment According to Gas Chromatography analysis, the methane gas obtained from chemical pretreatment and rumen with HRT 30 days is 47.93%, while the methane obtained from rumen pretreatment with HRT 30 days is 34.28%.

Thermochemical conversion of neem seed biomass to sustainable hydrogen and biofuels: Experimental and theoretical evaluation

This study aims to investigate the potential of neem seeds as a renewable energy source for producing bio-oil and syngas through both experimental and theoretical approaches. Neem seeds underwent thermal pyrolysis in a semi-batch reactor after undergoing acid wash pre-treatment. The effects of pyrolysis temperatures (350–550 °C) and heating rates (10–40 °C/min) on product yields were analyzed, and the highest achieved bio-oil yield was 60.2 % at 450 °C and a heating rate of 40 °C/min. In the theoretical section, the Aspen Plus software was employed to simulate the process of steam gasification of neem seeds to identify optimal operating conditions for maximizing hydrogen production and cold gas efficiency (CGE) while maintaining an ideal H2/CO ratio. By analyzing the impact of operating parameters such as steam-to-biomass (S/B) ratio and temperature on the composition of the syngas stream, H2/CO ratio, and CGE, the study determined that the optimal operating conditions are an S/B ratio of 0.9 and temperatures ranging from 650 to 750 °C. The findings of this study can shed light on the potential of neem seed as a non-edible biomass source for renewable energy production, which can help reduce greenhouse gas emissions and mitigate the negative impacts of traditional energy sources on the environment.

Comparative assessment of biochar produced from LDPE and neem leaves using batch and semi-batch biomass fuel-based reactors

This research aims to investigate and compare the properties of biochar derived from low-density polyethylene (LDPE) and neem leaves, utilizing both batch and semi-batch biomass fuel-based reactors for co-carbonization. While previous studies have primarily employed electrical-powered or biomass fuel-based batch reactors, this study introduces the innovative approach of utilizing a semi-batch reactor, marking a significant advancement in biochar production. The co-carbonization process lasted for ∼2 h in the batch-based system and nearly 3 h in the semi-batch system. The semi-batch system achieved higher temperature peaks in comparison to the batch-based system. In terms of biochar yield, the batch-based system generated a biochar yield of 30.35%, while the semi-batch system yielded 17.3%. Through BET analysis, it was determined that the biochar produced using the semi-batch reactor had a surface area of 227 m2/g and a pore diameter of 2.116 nm. Similarities and differences in functional groups among the biochar samples produced using the semi-batch and batch reactors were identified through FTIR analysis. By utilizing EDX spectroscopy, it was observed that the batch-based system contained seven elements, whereas the semi-batch-reacted sample had similar elements but lacked nitrogen, potassium, and magnesium. The semi-batch-reacted sample exhibited an increased carbon content, whereas the concentrations of other elements decreased when compared to the batch-reacted sample. The biochar samples can be applied in various applications, including water treatment, energy conversion, and storage. The findings of this study contribute to sustainable waste management practices, carbon sequestration efforts, and the development of innovative solutions for various industries.

Enhanced mineralization of bisphenol A by electric arc furnace slag: Catalytic ozonation

The catalytic ozonation of bisphenol A (BPA) was performed using an industrial solid waste as catalyst: electric arc furnace slag (EAFS). The characterization of the catalyst (SEM/EDS, XRD, surface area, pHPZC and Mössbauer spectroscopy) showed low surface area, alkaline nature and a composition rich in Fe, Ca, Si, C oxides, with minor content of Mg, Mn and Al. Ozonation experiments were carried out in a semi-batch reactor at room temperature at different initial pH conditions: from alkaline (natural pH 10.5) to acidic (controlled pH 3) aqueous media. Catalytic ozonation experiments showed complete BPA removal and remarkable total organic carbon conversions (62–80 %) over the broad pH range explored. The highest mineralization levels were obtained under basic pH, which was attributed to the generation of hydroxyl radical given by the presence of OH− and precipitation reactions of intermediates promoted by Ca oxides. Under acidic conditions the presence of EAFS notoriously enhanced BPA mineralization compared to single ozonation, due to the activity of leached species. The stability of the material was tested in 4 ozonation cycles. EAFS activity was mostly sustained under acidic conditions while a reduction was observed under uncontrolled pH condition, which was associated with a marked pH decrease. However, the residual activity still allowed complete BPA degradation and high mineralization levels (> 50 %). EAFS is a low-cost material that exhibits high activity and reasonable stability in catalytic ozonation of BPA. The valorization of this waste constitutes a technological alternative that could benefit both metallurgical and water treatment plants.

Fabrication of lipase immobilized-carboxylated cellulose nanocrystals as biocatalyst for enzymatic hydrolysis of palm oil and its kinetical study

This research focuses on the production of free fatty acids (FFA), one of the essential components in the oleochemical industry, through the enzymatic hydrolysis process of palm oil at low temperature and pressure using cellulose nanocrystals (CNCs) as lipase immobilization support. Furthermore, the kinetic behavior of this hydrolysis reaction with the presence of lipase immobilized-CNCs (lipase@CNCs) was studied to find the optimum condition for designing the reactor. According to FTIR and TEM analyses, CNCs were successful in immobilizing lipases, as ascertained by the appearance of amide peaks from the formation of bonds between CNCs and lipases and the thickening of the surface of the CNC morphology after immobilization. As a result, the optimum immobilization conditions were obtained at a lipase concentration of 1.5 mg/mL, an immobilization time of 2 h, and the CNCs/EDC ratio of 1:3. Moreover, the Michaelis-Menten model with the inhibition product fitted with the experiment and lipase@CNCs has the highest Vmax value at a temperature of 40 °C of 15.53 mM/h with a KM of 99.80 mM and an Ea of 41.07 kJ/mol. The simulation results show that the semi-batch reactor can achieve a higher conversion at the beginning of the reaction with a conversion of 28%. Therefore, using lipase@CNCs in hydrolysis processes is expected to be one of the strategies that can overcome the limitations associated with existing methods in terms of high energy consumption.

Catalytic Co-Pyrolysis of Mesua ferrea L. De-Oiled Cake and Garlic Husk in the Presence of Red-Mud-Based Catalysts

Utilizing lignocellulosic biomass as a renewable energy source for the production of sustainable fuel is of paramount importance. This study focuses on the catalytic co-pyrolysis of Mesua ferrea L. de-oiled cake (MDC) and Garlic husk (GH) as potential feedstocks for bio-fuel production. The pyrolysis experiments were conducted using a semi-batch reactor under inert conditions at temperatures of 500, 550, and 600 °C, with a heating rate of 10 °C min−1, a particle size below 1 mm, and an inert gas flow rate of 80 mL min−1. The findings reveal that temperature significantly influences the yield of pyrolytic products. However, GC-MS analysis detected higher oxygenated compounds in the bio-oil, negatively impacting its heating value. To improve fuel quality, co-pyrolysis with and without a catalyst for a feedstock ratio of 1:1 w/w was performed. Red mud, an alkaline waste mainly composed of Fe2O3, Al2O3, and SiO2, is a hazardous environmental concern from aluminum production and is used as a catalyst. The red-mud catalysts reduced oxygen concentration and increased carbon content, acidity, and heating value in the pyrolytic oil. GC-MS analysis of the bio-oil confirmed that using catalysts combined with MDC and GH significantly decreased the concentration of acidic and aromatic compounds, thereby improving the pyrolytic oil’s higher heating value (HHV).

Membrane-separated reactor for an integrated CO2 capture-mineralization process using carbonic anhydrase

To achieve carbon neutrality through CO2 mineralization, it is important to design the novel reaction process through a distinct understanding of the critical reaction steps, CO2 hydration, and calcium carbonation. A semi-batch system was introduced to conduct a model mineralization reaction to confirm the reaction-determining step (RDS) of CO2 mineralization. The CO2 hydration step was confirmed as RDS according to various model reactions in a semi-batch reactor. CA enzyme was introduced to promote CO2 hydration to increase the overall reaction rate. With the introduction of the CA enzyme, the hydration reaction rate was increased by about 4-fold, but the CA enzyme was lost due to coprecipitation with CaCO3 during the reaction. A membrane-separated reactor was designed to maintain high activity and decrease the loss of CA enzyme during the reaction. Furthermore, in the membrane-separated reactor, the CA enzyme facilitated the CO2 mineralization much more effectively in the K2CO3 aqueous solution than in the D.I. water because the K2CO3 aqueous solution has a higher CO2 absorption capacity and a weekly alkaline condition favorable for CA enzyme operation. Finally, by proposing a continuous reaction system for reusing enzymes and water, we suggested that the membrane-separated reactor could be applied in practical CO2 capture-mineralization.