Behavior of sulfur species present in atmospheric residue in fluid catalytic cracking
Behavior of sulfur species present in atmospheric residue in fluid catalytic cracking
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DOI：
10.1016/j.fuel.2007.02.030
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发表时间：
2007-12
期刊：
影响因子：
7.4
通讯作者：
H. Mizutani;Y. Korai;I. Mochida
中科院分区：
文献类型：
--
作者：
H. Mizutani;Y. Korai;I. Mochida
由于加氢脱硫后的常压渣油（HDS-AR）中的硫物种决定了随后的流化催化裂化（FCC）中产品汽油的硫含量，因此迫切需要选择性去除常压渣油（AR）中的硫物种。因此，在本研究中，HDS-AR和FCC汽油中的硫物种之间的相关性进行了探索。采用蒸馏法将HDS-AR分馏为减压瓦斯油（VGO）和减压渣油（VR）。采用微活度法测定了加氢脱硫-AR（S= 3000 massppm）及其减压馏分油（S= 900 massppm）的反应活性，以明确加氢脱硫-AR中哪些馏分和含硫化合物转化为汽油及其硫物种。由HDS-AR和VGO制得的产品汽油的收率和硫含量分别为45.0mass%和52 massppm和47.7mass%和14 massppm。HDS-AR汽油的硫含量明显高于HDS-VGO汽油。HDS-AR中的饱和馏分和芳烃馏分主要在FCC工艺中转化为汽油，从而提供与HDS-VGO和HDS-AR相似的汽油产率。在HDS-AR和HDS-VGO的汽油中，噻吩、甲基噻吩和苯并噻吩是主要的硫物种。这些硫物种分别来自减压馏分油中的苯并噻吩和减压馏分油中的二苯并噻吩，它们分别通过氢转移开环和催化裂化脱烷基反应生成。在FCC中，H2S和烯烃也产生硫化合物，增加了产品汽油中的硫含量。来自HDS-AR的汽油中的硫含量高于来自HDS-VGO的汽油中的硫含量，这归因于在FCC过程期间产生更多的H2S以及进料中存在的二苯并噻吩。
The selective removal of sulfur species in atmospheric residue (AR) is strongly wanted since the species of the hydrodesulfurized AR (HDS-AR) define the sulfur content of the product gasoline in the subsequent fluid catalytic cracking (FCC). Hence, the correlations between sulfur species in HDS-AR and FCC gasoline were explored in the present study. HDS-AR was fractionated into vacuum gas oil (VGO) and vacuum residue (VR) by distillation. Reactivities of HDS-AR (S=3000mass ppm) and its VGO (S=900mass ppm) were measured by micro activity test to clarify which fractions and sulfur compounds in HDS-AR were converted into gasoline and its sulfur species. The yields and sulfur contents of the product gasoline were 45.0mass% and 52mass ppm from HDS-AR and 47.7mass% and 14mass ppm from VGO, respectively. The sulfur content of the gasoline from HDS-AR was markedly higher than that from HDS-VGO. The saturate and aromatic fractions in HDS-AR are mainly converted to the gasoline in the FCC process, providing similar gasoline yields from HDS-VGO and HDS-AR. Thiophene, methylthiophenes, and benzothiophenes were major sulfur species in both gasolines from HDS-AR and HDS-VGO. Such sulfur species are concluded to be derived from benzothiophenes in VGO and dibenzothiophenes in VR fractions, respectively through hydrogen transferring ring opening and dealkylation during FCC. Sulfur compounds are also produced from H2S and olefins in FCC, increasing the sulfur content in the product gasoline. The larger sulfur content in the gasoline from HDS-AR than that from HDS-VGO is ascribed to more H2S being produced during the FCC process as well as dibenzothiophenes being present in the feed.