Software module simplifies reaction-kinetics modeling,
ties into multiphysics package to handle nonideal reactors

BURLINGTON, MA - Until today, setting up the simulation of a chemical process that involves many reactants with continually changing concentrations has been an arduous task that could take many hours. In contrast, the COMSOL Reaction Engineering LabTM allows users to set up and solve such problems in a matter of minutes. This tool will prove valuable in many application areas, not just in education and process industries but in others ranging from atmospheric chemistry to drug release in biomedical engineering.

A graphical user interface lets scientists, engineers, or researchers describe chemical-engineering problems in a straightforward manner: they simply enter the chemical-reaction formulas as they would write them on a piece of paper. The software then sets up the corresponding kinetics, material and energy balances using the mass-action law or user-defined expressions. During this process, the Reaction Engineering Lab can also calculate the thermodynamic and transport properties of reacting mixtures. The end result of these computations is a plot or tabular output of the system behavior, often reactant composition or temperature as a function of time. This streamlined work methodology makes it incredibly efficient to investigate the influence of different assumptions and reaction mechanisms in detailed kinetic studies.

The COMSOL Reaction Engineering Lab integrates a state-of-the-art solver (DASPK, developed by Professor Linda Petzold of the University of California, Santa Barbara). At the press of a button the software automatically solves material balances and energy balances including the complicated reaction-rate expressions.

The Reaction Engineering Lab also ships with a copy of COMSOL Script. This package-which itself is a command-line interpreted language that provides 500 commands for matrix and numeric computations plus visualization-allows users to couple multiple reactor models developed with the Reaction Engineering Lab to simulate a complex process or production line.

All types of reactors

Running as a standalone package, the Reaction Engineering Lab's equation solver handles chemical reactions in a perfectly mixed reacting system or in tubular reactor with variations in one space variable. When moving concepts to actual plants and processes, though, other aspects come into play. Thus, this software integrates seamlessly with the developer's flagship product COMSOL Multiphysics and the Chemical Engineering Module. With this combination it becomes possible to simulate reactors with an arbitrary geometry and spatial variations in concentration and temperature, whether in 1D, 2D, or 3D.

It is extremely convenient to first study a reacting system in the Reaction Engineering Lab to investigate different kinetic assumptions; only when the user has full confidence in these results does that person then generate the input data and equations needed for high-fidelity models in the Chemical Engineering Module. Together with COMSOL Multiphysics, it solves the flow field, composition, and temperature distribution in a nonideal reacting system.

Many application areas

The COMSOL Reaction Engineering Lab will be of great interest to scientists, engineers and researchers in a wide range of fields. Just a few examples where the package can considerably speed up an analysis or design include:

• Education - This software puts the focus on the actual chemistry and physics of a problem, and it presents results in an easy-to-understand graphical form. Thus students do not get sidetracked with numerics or solving reaction-rate equations. The package is especially interesting to instructors teaching all levels and branches of chemistry (introductory courses, physical chemistry, organic chemistry), chemical engineering, bioengineering (for example, enzyme reactions), biology (such as when studying microorganisms), as well as surface chemistry and surface physics.
• Bioengineering - A model can, for instance, analyze drug release from a biomaterial matrix to damaged tissue. It involves rate expressions for drug dissociation/association reactions as well as matrix degradation by enzyme catalysis. The detailed reaction/transport description allows the investigation of design parameters such as the effect of matrix degradation on drug release as a function of time and geometry.
• Pharmaceuticals - In examining a catalytic cycle for the synthesis of a drug such as Ibuprofen, the kinetics analysis involves comparing the solved model to experimental data. If needed, the user can modify the system of rate expressions using standard assumptions (steady-state, equilibrium) or by directly editing the rate expressions.
• Automotive and Environmental - The efficiency and durability of a diesel particulate filter are closely related to how soot deposits are removed from the porous filter walls. In such a model, the catalytic combustion of carbon is first investigated in the Reaction Engineering Lab. The reaction model is exported to the Chemical Engineering Module to compute both the flow of exhaust gas through a filter channel and the temperature distribution. The study reveals hot spots where the oxidation chemistry is accelerated.
• Atmospheric Chemistry - The software is useful for studying multiple pathways for ozone decomposition in the atmosphere, also including effects from thermal and transport processes. Furthermore, it allows for an efficient way of studying different assumptions regarding equilibrium, reversibility, or the manual pruning of reactions.
• Semiconductor Manufacturing and Materials Science - A typical study would examine a reactor for growing layers of gallium arsenide by means of chemical vapor deposition (CVD). In such a model, a detailed kinetic description of the gas phase and surface chemistry is coupled to the transport phenomena in the reactor. The result is a realistic simulation of the deposition process, which in turn can be used to minimize the expensive and time-consuming trial runs typical for CVD-reactor design.
• Process Industries - Removing chlorine from an off-gas, for example in the manufacturing of some plastics, is usually done by passing the gas through a caustic scrubber. The process can be described properly using ten reactions taking place in the bulk of the caustic stream and at the gas-liquid interface. The kinetic reactions for chlorine hydrolysis can be studied in the Reaction Engineering Lab before exporting them to the Chemical Engineering Module to create a full design model of the scrubber tower.

About the COMSOL Product Line

COMSOL Multiphysics is an industry-leading scientific software package for the modeling and simulation of any physics-based system. A particular strength is its ability to simultaneously account for interdependent, coupled physics, known in the industry as multiphysics phenomena. Researchers working in dedicated disciplines can also find add-on modules that have special user interfaces and optimized application setups; currently available are the Chemical Engineering, Earth Science, Electromagnetics, Heat Transfer, MEMS, and Structural Mechanics Modules. The package is available for the Windows, Linux, Solaris, and the Macintosh operating systems. Another product in the family is COMSOL Script, an interactive scripting language that works both as a general-purpose scientific computational tool and that also runs within COMSOL Multiphysics to automate tasks such as parametric studies and create customized user interfaces. Full product information is available here.

About COMSOL Inc

COMSOL was founded in 1986 in Stockholm, Sweden, and has grown to include offices in the Benelux, Denmark, Finland, France, Germany, Norway, Switzerland, and the United Kingdom; the company also has a US presence with offices in Burlington, MA, Los Angeles, CA, and Palo Alto, CA. Additional information about the company is available here.

Trademarks

COMSOL and FEMLAB are registered trademarks of COMSOL AB. COMSOL Multiphysics, COMSOL Script, and COMSOL Reaction Engineering Lab are trademarks of COMSOL AB. All Rights Reserved.