Evaluation of polyoxymethylene dimethyl ethers as a new type of diesel additives

Polyoxymethylene dimethyl ethers (PODE n ) is an emerging biofuel that has a great potential to become one of the competitive alternative fuels for diesel engine. In the present study, systematic studies were made to evaluate the influences of PODE n on the physical fuel properties that are routinely used to define the quality of diesel fuels. Such fuel properties were measured for the three (diesel + PODE n ) mixtures, diesels, and PODE n . The measured properties included cetane number , lubricity, density, viscosity, solidifying point, cold filter plugging point, flash point, and heat capacity. Comparisons of measured properties of the mixtures and their individual components were made to achieve the following purposes: First, to reveal the changes in the properties of diesels upon the addition of PODE n and in the properties of the (diesel + PODE n ) mixtures as the weight percent of PODE n is increased; Second, to see whether or not the addition of PODE n worsens the properties of diesels, in particular, whether or not the measured values of the (diesel + PODE n ) mixtures exceed the standard values set by the Beijing-VI. Novel theoretical equations were developed to quantitatively predict the density, viscosity, and heat capacity of the (diesel + PODE n ) mixtures in terms of the corresponding properties of the diesel and PODE n . Comparisons were made between measured and predicted properties and the agreements are excellent.