A Mini-Review on the Advances in the Kinetic Understanding of the Combustion of Linear and Cyclic Oxymethylene Ethers

Abstract

Oxymethylene ethers are valuable candidate e-fuels and, therefore, represent an important asset in the current energy transition. As such, the interest into predicting their combustion properties has grown significantly over the past decade. A detailed review of the existing kinetic studies of their combustion is presented, highlighting that the major part of the fundamental studies has been dedicated to dimethoxymethane (or OME 1 ). This molecule has served as a model molecule to elaborate rate rules toward predictive models of longer linear or cyclic oligomers, and detailed analysis of the existing kinetic models and their performance permits elaborating recommendations on the reaction classes to include any existing rate constant data. The current state of the art suggests that additional work is needed on precise determination of rate constants for hydrogen atom abstractions, and on experimental and theoretical studies of the longer linear, branched, and cyclic oligomers.

The unimolecular decomposition of dimethoxymethane: channel switching as a function of temperature and pressure

“…13–15 The smallest OME homologue, dimethoxymethane (DMM ≡ OME-1; where n in OME- n denotes the number of CH 2 O units in the CH 3 O(CH 2 O) n CH 3 backbone), plays a particular role because, besides representing a fuel additive in itself, 13 it can also serve as a model compound for the development of combustion mechanisms for higher OMEs. 6…”

“…ref. 6). These compounds are discussed as additives or replacements for conventional diesel fuel [7][8][9] because they possess diesel-compatible properties 7,8 and may be produced sustainably.…”

“…[13][14][15] The smallest OME homologue, dimethoxymethane (DMM h OME-1; where n in OME-n denotes the number of CH 2 O units in the CH 3 O(CH 2 O) n CH 3 backbone), plays a particular role because, besides representing a fuel additive in itself, 13 it can also serve as a model compound for the development of combustion mechanisms for higher OMEs. 6 A key process for the autoignition of any fuel/O 2 mixture is radical production from the closed-shell fuel molecule. This radical production can proceed via different pathways mainly depending on temperature.…”

Virtual Special Issue of Recent Advances in Fundamentals of Biomass and Biofuel Combustion

“…Westbrook et al provided an overview of detailed kinetic models, explaining how the combustion chemistry of biofuels (alcohols, aromatic oxygenates, alkyl esters, and cyclic ethers) differs from that of alkanes. The review of Fenard and Vanhove focused on a newly considered class of biofuels, oxymethylene ethers. Three more review papers discuss the use of biofuels in applied combustion processes.…”

Particle formation in oxymethylene ethers (OMEn, n = 2-4) / ethylene premixed flames

“…Oxymethylene ethers (OMEs), CH 3 O(CH 2 O) n CH 3 , also known as polyoxymethylene dimethyl ethers (PODEs or DMMs), are promising fuel candidates and are currently being investigated for self-ignition engine applications. They can be produced by renewable energy sources [1] yielding a neutral greenhouse gas balance. Recent studies have shown that OME fuels, pure or in blends, can significantly reduce carbon monoxide (CO), unburned hydrocarbons, and soot particles, e.g., [2][3][4][5][6].…”