Effect of Initial Temperature and Pressure on the Explosion Characteristics and Intermediate Reaction Products of Formic Acid Mixtures: A Theoretical Study

Formic acid is a promising candidate fuel that can be produced by reacting renewable hydrogen with carbon dioxide. However, the burning safety characteristics of formic acid–air mixtures have not been fully studied. This paper presents an extensive theoretical study of the adiabatic explosion pressure of formic acid–air premixed laminar flames at various initial conditions (composition of formic acid: 17–38% volume; initial pressure: 0.1–1.5 bar; initial temperature: 333–500 K), using the GASEQ software package. GASEQ software calculates chemical equilibria based on ideal gas behavior and is based on the hypothesis of adiabatic expansion inside a closed containment that allows ideal expansion. The influence of the initial conditions (pressure, temperature, and concentration) of formic acid–air mixtures on the adiabatic explosion pressures, maximum flame temperature, and peak concentrations of the main reaction intermediates is investigated and discussed. It is found that the adiabatic peak explosion pressure (calculated equilibrium pressure) of the studied concentrations decreases with increasing initial temperature and increases linearly with increasing initial pressure.