Virgin naphtha feed

The virgin naphtha feed after having been hydrofined over a cobalt molybdenum catalyst to remove sulftir compounds passes through the Powerformer. After stabilization, the aromatics are recovered by extracdon with... 

Isomerization. Isomerization is a catalytic process which converts normal paraffins to isoparaffins. The feed is usually light virgin naphtha and the catalyst platinum on an alumina or zeoflte base. Octanes may be increased by over 30 numbers when normal pentane and normal hexane are isomerized. Another beneficial reaction that occurs is that any benzene in the feed is converted to cyclohexane. Although isomerization produces high quahty blendstocks, it is also used to produce feeds for alkylation and etherification processes. Normal butane, which is generally in excess in the refinery slate because of RVP concerns, can be isomerized and then converted to alkylate or to methyl tert-huty ether (MTBE) with a small increase in octane and a large decrease in RVP. 

Hydrofining is applied to virgin naphthas mainly in the form of a pretreatment step for the feed to catalytic reformers (Powerforming). Sulfur levels of 5 parts per million (ppm) or less are required to avoid deactivation of the platinum reforming catalyst. 

The new developments in catalyst improvements and in process optimization have brought new opportunities to directly process virgin naphtha from atmospheric distillation along with benzene and benzene precursors extracted from reformer feeds. This can eliminate the need for a separate naphtha hydrotreater as well as sepa-... 

Table VI presents the over-all material balance on the H-Oil unit used in this case. Conversion is achieved, of all but 9 vol % of the feed, into material boiling below 650°F. The sulfur contents of the distillate fractions produced are quite low, and should it be desirable to control the sulfur content of all of the steam cracker charge, the virgin naphtha and distillate could also be processed in the H-Oil unit to achieve an over-all purification of steam cracker charge.

Pulling lighter jet fuel components into heavy virgin naphtha to meet the jet fuel flash spec not only reduces jet fuel production, it also downgrades the quality of the naphtha reformer feed. 

Feed Virgin/cracked naphtha Light cycle oil, diesel Kerosene Vacuum gas oil... 

Catalyst pellets, x 3 in., with molybdena content from 6 to 15 % were used to reform a heavy virgin mixed naphtha with a research clear octane number of 39, a 240-430° F boiling range (ASTM), and a sulfur content near 0.1%. Pilot-plant studies were made at 488 to 530° and 250 psi. The feed rate was 1.0 volume of oil per volume of catalyst per hour and the hydrogen addition rate, 2500 SCF/Bbl. Activity and yield studies were made with the cogelled catalysts whereas activity determinations only were made on the impregnated catalysts. 

The properties of the naphtha feedstock utilized in the experimental campaign are presented in Figure 2. The source of the feedstock was Kuwait crude. This naphtha feedstock was synthesized by blending 35 volume percent light Kuwait and 65 volume percent heavy Kuwait. This blend does not occur in the virgin crude and as such is somewhat heavier than the true virgin feed. The isoparaffins were about 60% of the total paraffins and the alkylcyclohexanes were about 60% of the naphthenes. 

Although Fig. 21-12 shows an older type bucket elevator plant, it was used here because of the complete operating data. The feed of 3,161 bpd of 25.4 API virgin gas oil (about 1.18 per cent sulfur) plus 231 bpd of 40.4 API naphtha, plus 4,479 bpd of 22.6 API recycle stock, produced the following products ... 

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