| Developing oxygenated clean fuel with low pollutant emissions,especially to develop clean diesel and "coal-based oil" and other non-petroleum-based clean fuel that can effectively reduce carbon emissions and PM2.5 emissions is an important direction for energy development.The previous research results of this research group show that mixed methyl ethyl oxalate(mMEO)with methyl ethyl oxalate as the main component has many advantages including a low melting point,a low cloud point,high boiling point,flash point and octane number,and has good miscibility with gasoline and a large density,high thermal efficiency,low concentration exhaust emission,low production cost,etc.The series of different oxygen content of clean gasoline can be formulated.It has great potential as a non-petroleum-based oxygenated fuel and fuel additives.However,the most cost-effective mixed methyl ethyl oxalate(mMEO)is easily separated phases in diesel,and the solubility of mixture fuel is not high.Only when the temperature reaches above 85?,the two fuels can be miscible in any mass ratio;Coal-based diesel produced by the coal indirect method has the performance advantages as high-quality diesel and aviation fuel with low alkenes and aromatic content,low sulfur content,and high cetane number.However,due to the low density,coal-based diesel does not meet diesel standard requirments and cannot be sold as diesel products.Therefore,expanding the range of raw materials of mixed oxalate,utilizing the cost-effective series of mixed oxalate products to develop oxygenated diesel fuel additives and oxygenated clean diesel with oxalate as the main component that can be miscible with petroleum-based or coal-based diesel at low or normal temperature and also meet the national standards of No.0 or other grades of diesel.It has great significance of expanding the diesel raw material pathway,alleviating the dependence on petroleum,and saving energy and reducing emissions.We have found that dimethyl oxalate(DMO)content in mixed methyl ethyl oxalate(mMEO)is a key factor to mixed fuels' cloud point through the further research.Therefore,in this paper,mMEO that its boiling point is above 179? and the DMO content is less than 0.5%were obtained by distillation to control and adjust the DMO?MEO and DEO three compositions of industrial grade mMEO,it can be used as an oxygenated traditional diesel additive with 10%addition.The diesel-mMEO-n-butanol found butanol has the best effect and diesel-mMEO-mixed monoglyceride two ternary mixed systems that add up to 40%and meet the cloud point requirements of No.0 traditional diesel have been formulated through the research of ternary mixture systems of seven low-carbon alcohols and glycerol fatty acid monoglyceride in diesel.In further research,we have found that the content of low-boiling alcohols in oxalate product components affects the flash point of the binary mixed fuel systems.In order not to reduce the flash point of oxygenated diesel,the content of n-butanol in the mixed fuel must be less than or equal to 0.4wt%.In order to increase the flash point and the miscibility of fuels,using cheap and easily available DMO as the synthetic raw material,and using n-butanol produced by biological fermentation?low-carbon mixed alcohols with DMO through transesterification reaction to synthesize mixed oxalate that can increase the miscibility of diesel,improve the cetane number and additons.We have systematically studied on the miscibility and the cloud point of binary and ternary systems about the series of asymmetric oxalate and their mixtures,low-carbon alcohols and petroleum-based and coal-based diesel.The properties of the binary and ternary systems such as the cloud point,freezing point,density,viscosity,flash point,etc.have been tested.Based on fixing national standard and considering the cost-effective advantages,we developed ME10-traditional diesel,MB15-traditional diesel,and MB20-coal-based diesel,etc.five oxalate-diesel formulations that meet the No.0 diesel national standard requirements.Furthermore,diesel engine tests have also shown that the soot content is significantly reducted.This paper is also mentioned that there is a certain correlation between the average carbon chain length of oxalate and the solubility between diesel which as the average carbon chain length increases,the cloud point of the mixed fuel decreases.Therefore,we made the formula prediction to the above correlation.Controlling the molar ratio of methyl groups to other groups above C2 in the mixed oxalate and the content of low-carbon alcohols and DMO,and fully utilizing the plentiful ethanol,butanol,etc.that can be biofermented and synthesized can develop large addtion and cost-effective binary and ternary coal-based and petroleum-based clean new oxygenated diesel systems. |
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