流化催化裂化汽油加氢改质理论研究

A Study on FCC Gasoline Hydro-upgrading

生产低硫、低烯烃和高辛烷值的清洁汽油是能源经济可持续发展的必然要求。我国于2011年在全国范围内实施《轻型车污染物排放限值及测量方法(中国Ⅳ阶段)》标准,要求汽油中烯烃体积分数不大于18%,芳烃体积分数不大于35%,硫含量不大于50μg/g。我国成品汽油约80%来自流化催化裂化(FCC)汽油,FCC汽油中的硫含量占汽油中硫含量的90%左右,FCC汽油具有较高的烯烃含量(质量分数为30%～55%)和较高的硫含量(150～1500μg/g)。FCC汽油中的硫主要以噻吩和噻吩衍生物等硫化物的形式存在。分析FCC汽油馏分中烃类组成对汽油辛烷值的贡献,以及硫化物分布情况;从热力学角度对氢转移、异构化和芳烃生成等反应发生的可能性及结果进行初步预测。建议在深度脱硫的前提下,更多地保留高辛烷值的烯烃组分,并使烯烃高选择性地向芳烃转化,以维持产品汽油的辛烷值。

Producing clean gasoline with low sulfur and olefin contents and high octane number is required by the need for achieving sustainable growth of energy economy.China began implementing the Limits and Measurement of Pollutants Emitted by Light Vehicles(China Phase Ⅳ) in 2011 nationwide.According to the standard,the volume fraction of olefin in gasoline should not exceed 18%,that of aromatic hydrocarbon not exceed 35%,and the content of sulfur not exceed 50μg/g.Around 80% of gasoline products in China come from FCC gasoline and the sulfur content of FCC gasoline accounts for some 90% of sulfur in gasoline.FCC gasoline contains high contents of olefin(mass fraction:30%-55%) and sulfur(150-1500μg/g).Sulfur in FCC gasoline primarily exists in the forms of thiophene and thiophene derivatives.The article analyzes the contribution of hydrocarbon composition in FCC gasoline fractions to octane value and distribution of sulfide and conducts a preliminary forecast of the possibility and results of reactions such as hydrogen transfer,isomerization and aromatic hydrocarbon generation from a thermodynamic perspective.The article suggests retaining more high octane-value olefin components while ensuring deep desulfurization and highly selectively converting olefin to aromatic hydrocarbon to maintain the octane value of gasoline products produced.