LPG汽车燃料供给系统中残留物成分与来源

Composition and source of residue in fuel supply system of LPG vehicle

通过大量试验和理论分析,对LPG(液化石油气)汽车在使用过程中燃料供给系统内残留物的成分和来源进行了深入系统的研究。结果表明:残留物的成分随LPG组分(尤其是杂质成分和含量)的不同而有所变化。常出现的残留物成分有酯类、重质烷烃、单质硫、硫化铜及硫化亚铜等。酯类来自于橡胶制件添加剂(邻苯二甲酸二辛酯),其含量随LPG混合物溶度参数的增加而增加;重质烷烃(C15-C35)主要来源于LPG输运过程中压缩机或泵类的润滑机油,在严格控制1,3-丁二烯含量的前提下,并不会由其他单烯烃聚合而成;硫及硫化铜数量决定于LPG中的硫含量,严格控制LPG中的单质硫和H2S的含量可以大幅降低残留物中硫化物的成分,限制使用铜质LPG管路可以避免硫化铜、硫化亚铜的生成;通过精制加工处理,合理控制成分,国产液化石油气能够满足汽车使用要求。

The composition and the source of the residue formed in the fuel supply system during operation of the LPG vehicle were investigated by means of the specially designed experiment, the dynamometer bench test, the chemical analysis, and the theoretical study. The results showed that the composition of the LPG fuel residue varies with the variation of the LPG composition, especially its contaminants and their contents. The common residues appear to be phthalates, heavy alkanes（C15-C35）, elementary sulfur, copper sulfide, and cuprous sulfide, etc. The analyses revealed that the phthalates come from the rubber additives（e, g. phthalic acid dioctyl phthalate）, and their content increases with the solubility parameter of the LPG mixture. The heavy alkanes come from the lub oils in the compressor or pump during refining, transport and storage, not from polymerization of mono- alkenes under the strictly limitation of 1,3-butadiene. The contents of sulfur and copper sulfide depent upon the sulfur content in the LPG, and strict control of the content of elementary sulfur and hydrogen sulfide may decrease significantly the content of the sulfides in the LPG residue. Limited use of copper LPG pipeline may restrain the formation of copper sulfide and cuprous sulfide. By means of careful refining and proper controlling LPG composition, the domestic LPG meet the requirements from the LPG vehicle.