On the Second Explosion Limits of Hydrogen, Methane, Ethane, and Propane

Abstract

In this work, we have first investigated the explosion limit behaviors from hydrogen to propane through numerical simulations and validated with the available experimental data. The shape of the explosion limit curves and the possible turning points ( P 1–2 , T 1–2 ), first to second limit transition, and ( P 2–3 , T 2–3 ), second to third limit transition that bound the second explosion limit as a function of the fuel carbon number, have been examined. Results show that with an increase of methane mole fraction in the hydrogen/methane system, the upper turning point ( P 1–2 , T 1–2 ) remains almost unchanged and the lower transition point ( P 2–3 , T 2–3 ) rotates counterclockwise around ( P 1–2 , T 1–2 ). With a further increase of carbon number, ( P 1–2 , T 1–2 ) moves to the lower-pressure and -temperature region and ( P 2–3 , T 2–3 ) gradually moves to the lower-pressure and higher-temperature region. The slope of the second explosion limit is inversely proportional to the carbon number, k PT = 0.0069 – 0.005/( X c – 0.7), approximately. Second, a sensitivity analysis has been conducted to study the elementary reaction on the second explosion limits. The results show that the chain branching and termination reactions governing the explosion limit of hydrogen have a little effect on the second explosion limit of methane. The C 2 H 5 O 2 H decomposition to form OH radicals is dominant in controlling the nonmonotonic behavior of the second explosion limit of C 2 H 6 . The second explosion limit behavior of propane is governed by three sets of reactions in the low-temperature oxidation process.

Energy-Efficient Enhancements on the Ethylene Process by Oxidative Dehydrogenation of Ethane Improve Economic Viability and Help Reduce Carbon Intensity

“…If N 2 had been chosen as inert diluent, a minimum of 46 mol % would have been needed in the mixture for ethane to reach FIP at ambient conditions. 27 Given the different capacity to reduce flammability between N 2 and H 2 O, 24 a high % of H 2 O as diluent was chosen to stay above the FIP.…”

Study on the Influence of Vent Shape and Blockage Ratio on the Premixed Gas Explosion in the Chamber with a Small Aspect Ratio

“…While bringing convenience to people, natural gas also poses greater safety risks. In recent years, some natural gas explosion accidents have occurred frequently, causing serious casualties and social and economic losses. − At present, there are more studies on the combustion and explosion problems in the safe transportation process of large aspect ratio pipelines, concentrating on the study of the influence of characteristic parameters such as pressure relief ratio, opening pressure, opening time, and blocking ratio on the natural gas-constrained explosion process, − and it was found that when the blockage ratio is set reasonably, the power generated by the explosion can be effectively reduced. − Given this, how to scientifically and effectively set the shape of the vent, the blockage ratio and opening position, and other characteristic parameters have become the focus of research by many scholars.…”

Study of Methane Explosion Suppression Characteristics of N2 and CO2 in Variable Cross-Section Ducts

“…Therefore, accidental leakage and improper handling during the production, processing, storage, and transportation of methane can result in the formation of complex combustible gas mixtures. Once the explosion conditions are satisfied, the gas explosion can cause serious property damage and casualties. − To prevent and control gas explosion accidents, effective measures need to be found to minimize the scope and intensity of gas explosion. Inert gases are often used as inhibitors of methane-air explosions.…”