定义Definition
催化重整是在含铂催化剂和氢气存在下,把低辛烷值的直馏石脑油转化为富含芳烃的高辛烷值汽油组分的炼油工艺,同时副产大量氢气。它也是生产苯、甲苯、二甲苯(BTX)的主要来源。
Catalytic reforming converts low-octane straight-run naphtha into high-octane, aromatics-rich gasoline over platinum-containing catalysts in the presence of hydrogen, and produces a great deal of hydrogen as a by-product. It is also the main source of benzene, toluene and xylenes (BTX).
原理Principle
重整催化剂是双功能的:铂(常加铼或锡)提供加氢-脱氢功能,氯化氧化铝提供酸性功能。主要反应有环烷烃脱氢生成芳烃、烷烃脱氢环化、正构烷烃异构化和加氢裂化。脱氢反应强烈吸热,因此工业上用三到四个串联反应器,中间加热,温度约 480–520 °C,压力 0.35–3 MPa。
The catalyst is bifunctional: platinum, often with rhenium or tin, provides hydrogenation–dehydrogenation, and chlorided alumina provides acidity. The main reactions are dehydrogenation of naphthenes to aromatics, dehydrocyclisation of paraffins, isomerisation of n-paraffins and hydrocracking. Dehydrogenation is strongly endothermic, so plants use three or four reactors in series with reheating between them, at about 480–520 °C and 0.35–3 MPa.
发展Development
1940 年代曾用铬钼氧化物催化剂。1949 年美国环球油品公司(UOP)的豪苏尔开发出铂重整(Platforming),使高辛烷值汽油的大规模生产成为可能。1967 年铂铼双金属催化剂问世,提高了稳定性;1971 年出现催化剂连续再生(CCR)工艺,可在低压下长期运行。
Chromium–molybdenum oxide catalysts were used in the 1940s. In 1949 Vladimir Haensel at UOP developed Platforming, making large-scale high-octane gasoline possible. Bimetallic Pt–Re catalysts arrived in 1967 for better stability, and continuous catalyst regeneration (CCR) came in 1971, allowing long runs at low pressure.
产品与意义Products and significance
重整汽油辛烷值可达 95–105。重整副产的氢气是炼厂加氢精制的重要氢源。由于汽油标准限制苯含量,重整装置常与芳烃抽提装置配套,把苯、甲苯、二甲苯分离出来用于合成纤维、塑料和溶剂。
Reformate can reach octane numbers of 95–105. The by-product hydrogen is a key supply for refinery hydrotreating. Because fuel standards limit benzene, reformers are often paired with aromatics extraction units that recover benzene, toluene and xylenes for fibres, plastics and solvents.
反应Reactions
Pt-Re/Al₂O₃(含氯),480–520 °C,临氢。
Chlorided Pt–Re/Al₂O₃, 480–520 °C, under hydrogen.
甲基环己烷脱氢生成甲苯
Methylcyclohexane dehydrogenates to toluene
正庚烷脱氢环化生成甲苯
n-Heptane dehydrocyclises to toluene
异构化提高辛烷值
Isomerisation raises octane
年表Timeline
- 1940
氧化物催化剂重整工艺出现
Oxide-catalyst reforming appears
- 1949
豪苏尔开发铂重整
Haensel develops Platforming
- 1967
铂铼双金属催化剂问世
Pt–Re bimetallic catalysts are introduced
- 1971
催化剂连续再生工艺投产
Continuous catalyst regeneration starts up