Butane isomerization vapor phase processes

Butane Isomerization. Five processes for butane isomerization were in commercial use by the end of World War II. These processes differ primarily in the method of contacting the hydrocarbon with the catalyst. Two are vapor-phase processes, which require periodic discard and replacement of the catalyst bed the other three are carried out in the liquid phase and are continuous with respect to catalyst addition and withdrawal. 

The butane isomerization process developed by the Universal Oil Products Co. is shown in Figure 4. In this process (3), the feed is maintained essentially in the liquid phase under pressure. Part of the feed is by-passed through a saturator, where it dissolves aluminum chloride. The feed later picks up hydrogen chloride and passes through the reactor, which is packed with quartz chips. Some insoluble liquid complex is formed, and this adheres to the quartz chips. The aluminum chloride in the feed is preferentially taken up by the complex, which thus maintains an active catalyst bed. The complex slowly drains through the reactor, losing activity en route. It arrives at the bottom in essentially spent condition and is discarded. Aluminum chloride carried overhead in the reactor products is returned to the reactor from the bottom of the recovery tower. The rest of the process is the same as in the vapor-phase processes. 

The third liquid-phase butane-isomerization process, shown in Figure 5, was developed by Shell as an improvement over the original intermittent vapor-phase process. 

Fiq. 12. Vapor-phase butane isomerization. Shell Isocel process. 

The third liquid-phase butane-isomerization process was developed by Shell Oil Company (16) as an improvement over the original intermittent vapor-phase process. The simplified flow diagram is shown in Figure 18. The aluminum chloride is handled, in this case, as an approximately 9% solution in relatively inert molten antimony trichloride the... 

The other vapor-phase butane isomerization process, developed cooperatively by the Anglo-Iranian Oil Co. and the Standard Oil Development Co., is somewhat similar to the Isocel process. In the AIOC-Jersey process (18), the reactor is initially filled with bauxite, and aluminum chloride is sublimed into the vaporized feed as necessary to maintain the desired catalyst activity. Upflow of vapor through the reactor is the customary arrangement. Since carry-over of aluminum chloride is not excessive at the usual rates of catalyst addition, about half of the commercial plants employing this process were not equipped with guard chambers. 

Butane vapor-phase isomerization a process for isomerizing n-butane to iso-butane using aluminum chloride catalyst on a granular alumina support and with hydrogen chloride as a promoter. 

The other vapor-phase butane-isomerization process was developed cooperatively by the Anglo-Iranian Oil Company and the Standard Oil Development Company. It is similar to the Isocel process, but it turns the volatility of aluminum chloride from a liability into an asset. The first plant was put into operation in October, 1942. This process is described (18) by the simplified flow diagram shown in Figure 15. 

The economic data concerning the production of isobutane by vapor phase n-butane isomerization, with and without recycling of unconverted n-butane, and concerning the production of isobutene by dehydrogenation, by the three main current industrial processes, are given in Table 6.5 a. The corresponding feed and product compositions are given in Table 6.5 b. 

Typical results obtained in the vapor-phase isomerization of n-butane are given in Table IX. The chemicals requirements for the process are 85 lb. of AICI3 and 70 lb. of HCl per 1000 bbl. of isobutane produced. 

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