Influence of hydrocarbon moiety of DMMP on flame propagation in lean mixtures

Abstract

Phosphorus-containing compounds (PCCs) have been found to be significantly more effective than CF3Br for reducing burning velocity when added to stoichiometric hydrocarbon-air flames. However, when added to lean flames, DMMP (dimethylmethylphosphonate) is predicted to increase the burning velocity. The addition of DMMP to lean mixtures apparently increases the equivalence ratio (fuel/oxidizer) and the combustion temperature, as a result of hydrocarbon content of DMMP molecule. Premixed flames studies with added DMMP, OP(OH)3, and CF3Br are used to understand the different behavior with varying equivalence ratio and agent loading. Decrease of the equivalence ratio leads to the decrease of inhibition effectiveness of PCCs relative to bromine-containing compounds. For very lean mixtures CF3Br becomes more effective inhibitor than PCCs. Calculations of laminar burning velocities for pure DMMP/air mixtures predict the maximum burning velocity of 10.5 cm/s at 4.04 % of DMMP in air and at an initial temperature of 400 K. Adiabatic combustion temperature is 2155 K at these conditions.

Experimental study on flame stability limits of lithium ion battery electrolyte solvents with organophosphorus compounds addition using a candle-like wick combustion system

“…This is contrary to the case (and ordinary experience) without any retardant in a candle-like flame configuration. High OPC addition was found to be marginally effective in terms of the retardation of gas-phase flames based on the condensation of phosphorus-containing intermediates and the fuel effect of OPC, which was found in extinguishment tests on a cup burner flame by using OPC-containing extinguish agents [8,9,25]. However, the aforementioned works did not consider reversal of the flame stability limits of the full and the wake flames.…”

Shock Tube/Laser Absorption and Kinetic Modeling Study of Triethyl Phosphate Combustion

“…In the literature, there have been studies on combustion of OPCs, trimethyl phosphate (TMP), and dimethyl methyl phosphonate (DMMP) being the most common because of their use as flame retardants. Hence combustion studies on these chemicals have been focused mainly on their influence as an additive in transformation, structure, and propagation of hydrogen and hydrocarbon flames. − Decomposition of these OPCs takes place via H-abstraction of methyl group by H or OH radical, which is a slow process, compared to six-center molecular eliminations that take place during decomposition of larger OPCs including sarin-GB. Hence, Zegers and Fisher − conducted pyrolysis studies of three larger OPC simulants: triethyl phosphate (TEP), diisopropyl methyl phosphonate (DIMP), and diethyl methyl phosphonate (DEMP) in a flow reactor and used gas-chromatography/mass-spectrometry along with Fourier transform infrared (FTIR) for product identification and quantification. − These experiments were performed within 700 to 900 K, and pyrolysis products time histories were measured within 15 to 90 ms residence time.…”

Review of Phosphorus Chemistry in the Thermal Conversion of Biomass: Progress and Perspectives

“…The model contains a much more extensive set of decomposition pathways compared to what is shown in Figures , , and . The models were later refined, and kinetics for propane flames were incorporated. , The model was used by others to evaluate experimental data, ,− and additional modifications of the kinetics were also proposed. , …”