Critical autoignition conditions for arbitrary reaction order.

Area of Science:

• Chemical Engineering
• Reaction Kinetics
• Thermodynamics

Background:

• Thermal explosion (TE) theory traditionally simplifies reaction kinetics and heat transfer.
• Existing models struggle with accurate predictions under varying ambient temperatures and reactant consumption levels.
• Understanding autoignition is crucial for safety and process design in exothermic systems.

Purpose of the Study:

• To theoretically analyze critical autoignition conditions for exothermic reactions across all reaction orders.
• To derive new analytical dependencies for parameters at the ignition limit.
• To determine conditions for thermal explosion degeneration for arbitrary order reactions.

Main Methods:

• Theoretical analysis of critical autoignition conditions.
• Calculation of analytical dependencies for ignition limit parameters.
• Development of critical parameter diagrams.

Main Results:

• Obtained calculated and approximate analytical dependencies for ignition limit parameters.
• Determined conditions for thermal explosion degeneration for arbitrary order reactions.
• Identified limitations of existing TE theory in predicting critical conditions at given ambient temperatures and intermediate reactant consumption.

Conclusions:

• Existing TE theory provides accurate ignition temperatures but fails in predicting critical TE conditions under specific ambient temperatures.
• The classical theory is inadequate for intermediate cases where reactant consumption is significant yet exhibits TE characteristics.
• The derived analytical dependencies offer improved predictions for autoignition and thermal explosion phenomena.