A Monte Carlo-Based Strategy to Assess Complex Kinetics: Application of the Null-Reaction Method to DAEM.

Area of Science:

• Chemical Kinetics
• Computational Chemistry
• Statistical Mechanics

Background:

• The Distributed Activation Energy Model (DAEM) is a standard statistical method for analyzing complex reaction systems with numerous parallel reactions.
• Existing DAEM implementations often rely on approximations, limiting accuracy in predicting conversion rates.
• There is a need to integrate chemical kinetics with heat transfer simulations using a unified computational framework.

Purpose of the Study:

• To develop an exact Monte Carlo integral formulation for the DAEM, bypassing traditional approximations.
• To introduce a 'null reaction' concept for accurately modeling temperature-dependent reactions under dynamic conditions.
• To provide a flexible computational tool applicable to diverse experimental activation energy distributions and temperature profiles.

Main Methods:

• Formulation of DAEM equations (isothermal and dynamic) as expected values.
• Transcription of expected values into Monte Carlo algorithms.
• Introduction of a null-event inspired 'null reaction' for dynamic temperature dependence (first-order reactions).

Main Results:

• The Monte Carlo integral formulation accurately computes conversion rates without approximation.
• The method demonstrates high adaptability to various analytical and experimental activation energy distribution functions.
• The approach accommodates arbitrary temperature profiles, enhancing its practical applicability.

Conclusions:

• The proposed Monte Carlo integral formulation offers an efficient and exact solution for the DAEM.
• This method is well-suited for coupling chemical kinetics with heat transfer in a single Monte Carlo simulation.
• The 'null reaction' concept provides a novel way to handle temperature-dependent kinetics in dynamic systems.