Single-stage hydrocracking

As an example, noble metal catalysts are effective only when sulphur levels are below approximately 500 ppm. Hence, such catalysts are only applicable in two-stage hydrocracking processes with interstage removal of H2S - they are not appropriate to single-stage hydrocrackers or two-stage units without intermediate H2S removal [3]. Such limitations will not apply to F-T wax processing. 

Figure 19. Single-stage hydrocracker hot H.P. separator, recycle to R1...

Table 13. Feed and Product Properties for a flexible Single-Stage Hydrocracker...

Figure 2. Single Stage Hydrocracking unit with Recycle. R = Reactor(s), F = Fractionation...

Figure 3. Typical Flow Diagram of Reactor Section of Single Stage Hydrocracker (or first stage of a two stage hydrocraeker)...

An impUcation arising from the above discussion on the impact of ammonia in the first- and second-stage reactor environments is the different requirements for the balance of acidity to hydrogenation functions for catalyst intended for service in different locations in the hydrocracker. Namely, a catalyst intended for use in first- or single-stage service would require a different acid/metal ratio than one in... 

Figure 16.n Hydrocracking catalyst performance in single stage recycle as a function of zeolite content and unit cell size. 

Figure 3. Simplified hydrocracking single-stage process flow diagram...

The choice of processing schemes for a given hydrocracking application depends upon the nature of the feedstock as well as the product requirements (Aalund, 1981 Nasution, 1986 Suchanek and Moore, 1986 Murphy and Treese, 1979). The process can be simply illustrated as a single-stage or as a two-stage operation (Figure 7-20). 

Figure 7-20 The hydrocracking process (a) single-stage process and (b) two-stage process.

Fig. 1 A hydrocracking unit that can be operated as a single-stage or two-stage process.

A two-stage residuum hydrocracker represents one additional level of complexity beyond the single-stage... 

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