The regulated emissions and PAH emissions of bio-based long-chain ethers in a diesel engine

Catalytic etherification is a new and developing method for the upgradation of pyrolysis bio-oil into high performance bio-based long-chain ethers. In this work, the application of bio-based long-chain ether oxygenated additives in diesel engines have been checked by focusing on their regulated emissions and PAH emissions. Four bio-based long-chain ethers with similar structures, including: Polyoxymethylene dimethyl ether , diglyme , dipropylene glycol dimethyl ether and tripropylene glycol methyl ether have been blended with diesel fuel and tested in a small-duty diesel engine. The results showed that long-chain ethers were beneficial to the reduction of regulated emissions by comparing to pure diesel. Polyoxymethylene dimethyl ether and tripropylene glycol methyl ether showed best performance among the four tested ethers. Polyoxymethylene dimethyl ether could reduce 56% CO, 23% NO and 93% soot emissions, while Tripropylene glycol methyl ether could reduce 52% CO, 28% NO and 88% soot emissions. Besides, the particle sizes of soot particles from the blended fuels were also reduced. What's more, the addition of bio-based long-chain ethers could reduce particulate PAHs emissions by 39% ~ 67% and reduce gaseous PAHs emissions by 25% ~ 44%, and the PAHs toxicity was also reduced by 32% ~ 55%. This work proved that the structure of oxygen atoms evenly distributed in the chain could efficiently suppress the production of soot precursors and eventually reduce the soot emission