Reaction engineering

BACKGROUND It is widely accepted that the poor thermostability of Baeyer–Villiger monooxygenases limits their use as biocatalysts for applied biocatalysis in industrial applications. The goal of this study was to investigate the biocatalytic oxidation of 3,3,5‐trimethylcyclohexanone using a thermostable cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) for the synthesis of branched ϵ‐caprolactone derivatives as building blocks for tuned polymeric backbones. In this multi‐enzymatic reaction, the thermostable cyclohexanone monooxygenase was fused to a phosphite dehydrogenase (PTDH) in order to ensure co‐factor regeneration. RESULTS Using reaction engineering, the reaction rate and product formation of the regio‐isomeric branched lactones were improved and the use of co‐solvents and the initial substrate load were investigated. Substrate inhibition and poor product solubility were overcome using continuous substrate feeding regimes, as well as a biphasic reaction syste...

BACKGROUND: It is widely accepted that the poor thermostability of Baeyer-Villiger monooxygenases limits their use as biocatalysts for applied biocatalysis in industrial applications. The goal of this study was to investigate the biocatalytic oxidation of 3,3,5-trimethylcyclohexanone using a thermostable cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) for the synthesis of branched 𝜺-caprolactone derivatives as building blocks for tuned polymeric backbones. In this multi-enzymatic reaction, the thermostable cyclohexanone monooxygenase was fused to a phosphite dehydrogenase (PTDH) in order to ensure co-factor regeneration. RESULTS: Using reaction engineering, the reaction rate and product formation of the regio-isomeric branched lactones were improved and the use of co-solvents and the initial substrate load were investigated. Substrate inhibition and poor product solubility were overcome using continuous substrate feeding regimes, as well as a biphasic reaction system with toluene as water-immiscible organic solvent. A maximum volumetric productivity, or space-time-yield, of 1.20 g L -1 h -1 was achieved with continuous feeding of substrate using methanol as co-solvent, while a maximum product concentration of 11.6 g L -1 was achieved with toluene acting as a second phase and substrate reservoir. CONCLUSION: These improvements in key process metrics therefore demonstrate progress towards the up-scaled Baeyer-Villiger monooxygenase-biocatalyzed synthesis of the target building blocks for polymer application.

Sulfur removal from natural gas, light hydrocarbons, diesel-range fuels, and heavy petroleum fractions is governed not only by intrinsic reaction chemistry but also by adsorption and catalytic surface phenomena, interphase mass transfer, internal diffusion, hydrodynamics, downstream separation, and energy input. This paper develops a diagnostic reaction-transport-separation framework for interpreting desulfurization performance across gas-and liquid-phase systems. Rather than providing an exhaustive review of all desulfurization technologies, representative routes are used to illustrate controlling regimes, including hydrodesulfurization, oxidative desulfurization, catalytic oxidation/sweetening, adsorption/reactive adsorption, and radical-assisted oxidation. Systems are classified as reaction-controlled, external-mass-transfer-limited, internaldiffusion-limited, separation-limited, energy/intensification-limited, or mixed using apparent kinetic constants, volumetric mass-transfer coefficients, effectiveness factors, Thiele moduli, and Damköhler-type ratios. Hydrodynamic cavitation is treated as an intensification layer that may improve interfacial renewal, oxidant activation, and apparent rates only when these benefits exceed energy, erosion, emulsion, and separation penalties. A dimensionless cavitation enhancement factor is proposed to relate apparent rate improvement to measurable cavitation intensity while avoiding double-counting of physical and chemical effects. Illustrative ODS and HDS calculations show how regime analysis prevents overinterpretation of apparent rate constants. The framework provides an engineering basis for selecting hybrid reactors and defining validation requirements for scale-up, including sulfur speciation, closed sulfur balances, independent mass-transfer measurements, catalyst or adsorbent durability, oxidant utilization, and energy-normalized sulfur removal.

An optimization model is presented to determine optimal operating policies for tailoring high density polyethylene in a continuous polymerization process. Shaping the whole molecular weight distribution (MWD) by adopting an appropriate choice of operating conditions is of great interest when designing new polymers or when improving quality. The continuous tubular and stirred tank reactors are modeled in steady state by a set of differential-algebraic equations with the spatial coordinate as independent variable. A novel formulation of the optimization problem is introduced. It comprises a multi-stage optimization model with differential-algebraic equality constraints along the process path and inequality end-point constraints on product quality. The resulting optimal control problem is solved at high computational efficiency by means of a shooting method. The results show the efficiency of the proposed approach and the benefit of predicting and controlling the complete MWD as well as the interplay between operating conditions and polymer properties. V

We report here an experiment for the chemical reaction engineering laboratory. The reaction between sodium hydroxide and ethyl acetate is conducted isothermally in a tubular reactor under isothermal, laminar flow, conditions. Steady-state reactor performance is followed at different space times and Reynolds numbers. Analysis of reactor performance is easily followed by direct sampling and titration. Comparisons between theory and experiment are in reasonably good agreement. The experiment demonstrates how concepts in transport phenomena, introduced early in the chemical engineering curriculum, are related to reactor engineering.

📘 Modeling of Chemical Kinetics & Reactor Design — A Cornerstone for Modern Chemical Engineers
Modeling of Chemical Kinetics & Reactor Design by A. Kayode Coker continues to stand out as one of the most influential resources in reaction engineering since its publication in 2001. It remains widely referenced across academia and industry, consistently ranking among the top performing chemical engineering publications on ResearchGate.
This book offers a comprehensive and practice driven exploration of how chemical reactions behave and how reactors should be designed to achieve safe, efficient, and economically optimized operation. It guides readers from foundational kinetics and reaction mechanisms into advanced modeling of batch, CSTR, PFR, catalytic, and multiphase reactors. The text also provides clear methodologies for analyzing kinetic data, fitting parameters, validating mechanisms, and translating laboratory results into full scale industrial reactor designs.
One of the book’s greatest strengths is its ability to bridge theory with real world engineering. The industrial case studies drawn from petroleum refining, petrochemicals, gas processing, polymerization, and environmental systems show how kinetic modeling directly informs design decisions, troubleshooting, optimization, and scale up. Engineers working in complex process environments often find these examples invaluable.
The book also anticipated the rise of computational modeling. Its algorithm friendly approach to solving differential equations, performing sensitivity analysis, and validating models makes it a natural companion for today’s engineers who rely on simulation tools and custom modeling workflows.
More than two decades later, the book continues to attract strong engagement from researchers and professionals. Its ResearchGate Research Interest Score places it above 98% of all chemical engineering items, underscoring its enduring relevance in graduate education, industrial practice, and advanced research.

Microfluidics has a wide range of applications in various fields, especially experimental sciences, chemical industries, microelectronics and pharmaceuticals. Given flow chemistry's advantages over traditional batch approach and wide applications, continuous-flow approaches using microreactors and other microfluidic devices have gained significant attention in recent years from academia and industries. This research studied the design and simulation of the proposed micromixers and microreactors using computational fluid dynamics (CFD) and COMSOL Multiphysics software. During the simulations, transport of dilute species and laminar flow physics were applied, with water used as the operational fluid, entering the microchannels with two different concentrations. Additionally, the mixing index was used as the objective function to quantitatively compare the performance of the microchips, which were calculated at four residence time levels: 20, 30, 40, and 100 minutes for each design. Based on the simulation results, microreactor 1 demonstrated a significantly better mixing index compared to microreactor 2, with its mixing index reaching 92.6% and 99.8% at residence times of 40 and 100 minutes, respectively. Following, microchips that indicated better performance were selected for the fabrication process using glass and CO2 laser engraving technique. After that, a leakage test was performed to ensure the appropriate fabrication method. Finally, an experimental mixing test was performed on the fabricated micromixer to show the good agreement between experimental and simulation outcomes.

Fluid Catalytic Cracking (FCC) is an important conversion process for the refining industry. The improvement of FCC technology could have a great impact on the public in general by lowering the cost of transportation fuel. A recent review of the FCC technology development by Bienstock et al. of Exxon indicated that the use of computational fluid dynamics (CFD) simulation can be very effective in the advancement of the technology. Theologos and Markatos used a commercial CFD code to model an FCC riser reactor. National Laboratories of the U.S. Department of Energy (DOE) have accumulated immense CFD expertise over the years for various engineering applications. A recent DOE survey showed that National Laboratories are using their CFD expertise to help the refinery industry improve the FCC technology under DOE`s Cooperative Research and Development Agreement (CRADA). Among them are Los Alamos National Laboratory with Exxon and Amoco and Argonne National Laboratory (ANL) with Chevron an...

In this paper, the optimum design of multistage chemostats (CSTRs) was investigated. The optimal design was based on the minimum overall reactor volume using different volume for each chemostat. The paper investigates three different microbial growth kinetics; Monod kinetics, Contois kinetics and the Logistic equation. The total dimensionless residence time (θTotal) was set as the optimization objective function that was minimized by varying the intermediate dimensionless substrate concentration (αi). The effect of inlet substrate concentration (S0) to the first reactor on the optimized total dimensionless residence time was investigated at a constant conversion of 0.90. In addition, the effect of conversion on the optimized total dimensionless residence time was also investigated at constant inlet substrate concentration (S0). For each case, optimization was done using up to five chemostats in series. Copyright © 2013 International Energy and Environment Foundation All rights reser...

CFD based modelling including diffusion and reaction within a meshed porous solid to represent a heterogeneous catalyst has seen a rapid growth in interest over the last decade. Early attempts to do this essentially represented the reaction simply as a heat source terms [1]. Developments in commercial and open source CFD sub-models and methods allowed meshing of the porous solid and the development of functions to model species diffusion and reaction within the porous phase. This approach, sometimes referred to as “hi-fidelity” reactor modelling, is now being widely published [2][3][4][5]. There remains though a shortage of rigorous model validation and verification. A significant number of published validations apply only a single “global” result to the validation (e.g. temperature, reaction conversion etc.) [6] which does not address the validity of the complex substructure of the overall model [7].

Calcination is a thermo-chemical process, widely used in the cement industry, where limestone is converted by thermal decomposition into lime CaO and carbon dioxide CO 2 . The focus of this paper is on the implementation and validation of the endothermic calcination reaction mechanism of limestone in a commercial finite volume based CFD code. This code is used to simulate the turbulent flow field, the temperature field, concentrations of the reactants and products, as well as the interaction of particles with the gas phase, by solving the mathematical equations, which govern these processes. For calcination, the effects of temperature, decomposition pressure, diffusion and pore efficiency were taken into account. A simple three-dimensional geometry of a pipe reactor was used for numerical simulations. To verify the accuracy of the modelling approach, the numerical predictions were compared with experimental data, yielding satisfying results and proper trends of physical parameters influencing the process.

The esterification of propionic acid with isopropyl alcohol was studied in an isothermal batch reactor. The activities of three different types of ion exchange resin catalysts (Amberlyst 15, Amberlyst 70 and Dowex 50 WX8) were investigated, and Amberlyst 15 was found to be an effective catalyst for the reaction. The effects of process parameters, namely, catalyst loading, alcohol to acid molar ratio and reaction temperature, were studied and optimized. Response surface methodology (RSM) was applied to optimize the process parameters as well as to investigate the interaction between process parameters. The internal and external diffusion limitations were found to be absent at a stirring speed of 500 rpm. The RSM model predicted response (83.26%) was verified experimentally with a good agreement of experimental value (83.62±0.39%). Moreover, the kinetics was studied and the Langmuir-Hinshelwood model was used to fit the kinetic data.

This research designed a mechanically agitated fermenter that operates with the principles of heat exchanger, sustaining fermentation process in a conducive thermodynamic state which promotes product (ethanol) yield as well as its concentration (purity), with a target of achieving 10 tons per day ethanol from cool-feed biomass (palm wine). The design shows that the target was achieved at the fermenter vessel Area (A 0) of 15.5917 m 2 with the use of 1271.1646 kg/day coolant (water), operating at a conservative heat flow of 505262.484 J/day. MATLAB simulation was used to access the dynamic behavior of the agitated fermenter over a range of biomass and time. From the developed models, the result showed that the reaction rate of fermentation ((dC_L)/dt) was proportional to the overall mass transfer coefficient per unit volume of the biomass (K_L a) measured in per hours of the fermentation (hr-1). This can be due to decrease in the feed mass of a fermenter due to biomass decay which increases the oxygen penetrability of the system. Decrease in the fermenter material (biomass) due to biomass decay was also observed. This implies promotion of the fermentation rate of the system as the rate of biomass fermentation ((dC_L)/dt) decreases with increase in feed value of biomass. The residence time of the system was also reduced which implies that there was an increase in the fermentation rate of the biomass hence, promoting satisfactory product yield and purity which is one of the target of this research.