Storage Stability and Material Compatibility of Poly(oxymethylene) Dimethyl Ether Diesel Fuel

Abstract

While a large part of traffic volume can be electrified to avoid local pollutant emissions, some applications will still require an internal combustion engine as an energy converter in the future. Construction machines such as vibratory plates, excavators, or emergency generators are examples of such applications. In order to reduce or avoid the pollutants of the remaining internal combustion engines, exhaust aftertreatment systems or synthetic fuels can be implemented. One category of these literature-discussed fuels is poly(oxymethylene) dimethyl ether (OME). In this work, neat OME as well as four OME− diesel blends and conventional diesel fuel as reference were investigated according to the material compatibility of two elastomers (NBR and FKM) and long-term storage stability of the fuel itself. The material compatibility of OME according to both elastomers NBR and FKM is difficult. The tensile stress test (DIN 53504), the Shore hardness (ISO 7619-1), and the compression set (ISO 815-1) show significant changes for neat OME compared to the diesel used elastomers. In addition, the change of mass and volume of the elastomers (DIN ISO 1817) are up to 75 wt % and 140 vol % higher compared to diesel fuel. Only FKM specimens, which were submerged in an OME−diesel blend with 5 vol % OME content, show comparable properties to the diesel reference. Based on the findings of this work, it is concluded that engines with NBR or FKM seals should replace their seals with OME resistant seals. In contrast, the long-term storage stability (ASTM D4625-14) of OME has much better properties than diesel fuel. No deposits were detectable after 24 weeks accelerated fuel aging at an ambient temperature of 43 °C.

A Batch Blending System for Continuous Production of Multi-Component Fuel Blends for Engine Laboratory Tests

“…All of the materials in the system are compatible with Class 1 fuels as well as resistant to aggressive fuels such as methanol, dimethyl ether (DME) and oxymethylene dimethyl ethers (OME) [27,28,29]. Hence, the material of the system consist of mainly stainless steel piping and PTFE hoses with stainless steel covering.…”

Comparing pathways for electricity-based production of dimethoxymethane as a sustainable fuel

“…8,24 However, engine modifications seem to remain indispensable for both DMM and OME 3-5 . 4,5,25 In addition to the potential direct application in internal combustion engines, DMM is a key intermediate in OME 3-5 production via paraformaldehyde, 26 trioxane, 27,28 or in novel routes via gaseous formaldehyde. 29,30 Commercial DMM production takes place via the condensation reaction of methanol and aqueous formaldehyde (FA).…”

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

“…The storage stability of OME 3–5 was studied according to ASTM Standard D4625-14 . Insoluble residues are determined depending on the storage time at 43 °C (mildly accelerated fuel aging method).…”

“…Both of these studies demonstrate that the stability of OME 3–5 is equal or better, compared to a reference diesel fuel. In contrast, however, the influence of OME 3–5 on standard fuel sealing materials such as fluorocarbon rubber (FKM) and nitrile butadiene rubber (NBR) is considerable …”