Platforming unit, CCR

The aromatics complex converts approximately 75% of the feed naphtha to petrochemical aromatics with the vast majority of the remainder being exported as raffinate and some hydrogen. With a modern aromatics complex flowscheme, a little over half of the mixed xylenes are produced in the Tatoray unit while the rest are produced in the CCR Platforming unit directly from the naphtha reforming. Having reviewed the framework of an aromatics complex we are now in a better position to understand the context of the continuous countercurrent liquid adsorptive Parex process which produces the primary aromatics complex product, p-xylene. 

Commercial plants UOP is the world s leading licensor of process technology for aromatics production. UOP has licensed more than 600 separate process units for aromatics production, including over 200 CCR Platforming units, 134 Sulfolane units, 80 Parex units, 61 Isomar units, 44 Tatoray units and 38 THDA units. 

The cover illustration shows the 100th CCR Platforming unit licensed by UOP and is reproduced with permission of UOP LLC. 

The naphtha feed is first sent to a UOP naphtha hydrotreating unit (1) to remove sulfur and nitrogen compounds and then sent to a UOP CCR Platforming unit (2) to reform paraffins and naphthenes to aromatics. 

The reformate produced in the CCR Platforming unit is sent to a stabilizer column, which strips off the light ends. The stabilizer bottoms are sent to a reformate splitter (3). The C fraction from the overhead of the reformate splitter is sent to a Sulfolane unit (4). The Cg-" fraction from the bottom of the reformate splitter is sent to a xylene fractionation section. The UOP Sulfolane unit extracts the aromatics and then individual high-purity benzene and toluene products are recovered in a BT fractionation section (5 6). 

The standard CCR Platforming process has a single reactor stack design as shown in Figure 8. However, CCR Platforming units have also been designed as a combination of stacked and single side-by-side reactors. The reactors are... 

Two cases are presented to compare the SR Platforming and CCR Platforming processes. The unit capacities are the same for the two modes of operation, but the CCR Platforming unit is run at a higher operating severity, 102 RONC compared to 97 RONC for the SR Platforming case... 

Operating Conditions. Table 6 shows the relative operating severities for the SR and CCR Platforming units. The CCR Platforming vmit operates at higher severity and lower reactor catalyst inventory. In addition, the CCR unit runs continuously compared to 12 month SR Platforming cycle lengths. 

Product Yields and Properties. Typical product yields for the SR and CCR Platforming units operating at the conditions presented in Table 6 are shown in Table 7. Many of the benefits of CCR Platforming are demonstrated in the Table 7. More and higher purity hydrogen is produced. The lower operating pressure of the CCR Platforming unit results in similar liquid volume jdelds... 

Laboratory simulation of metal dusting in CCR platformer units... 

Combined mixed xylenes from the CCR Platforming and Tatoray units make up the fresh feed to the Parex unit and Isomar unit loop. A typical composition... 

Chlorsorb Also called RVG Chlorsorb [Regenerator Vent Gas], A process for removing chlorine compounds (mainly HC1) from the waste gases from the CCR Platforming process. The chlorides are reabsorbed on the catalyst. Developed by UOP and now operated in several oil refineries in the United States and Argentina. 

The concept of LNA process is to utilize an existing fixed bed unit, which is typically unused catalytic reformer replaced by CCR, with minor modification. Based on the results of the fundamental and scale-up studies, a 2,250 BPSD demonstration plant was designed, which was originally used as a conventional platforming unit. 

A few years after UOP introduced the CCR Platforming process, another continuously regenerable reforming process design was offered by the Institut Francais du Petrole (IFP). The reforming unit designed by IFP differs most notably in that the reactors are always located side-by-side with catalyst transfer between each reactor. 

Table 6. Process Conditions/Severities of CCR vs SR Platforming Units...

The advantages of CCR Platforming over SR Platforming are so overwhelming that essentially all new catalytic reformers units are designed with continuous regeneration. 

UOP Platforming Semiregenerative CCR CycleMax regenerator product recovery system Over 800 units with 8 million b/d... 

The total capacity of the semiregenerative units exceeded 5.0 million b/d while CCR units reached 3.8 million b/d. The simultaneous use of CCR technology and bimetallic catalysts has given UOP a unique position in the field of catalytic reformer process licensing. Recent catalyst formulations have improved both aromatic and reformate yields. UOP has improved the performance of the conventional platforming process by incorporating a CCR system. The process uses stacked radial-flow reactors and a CCR section to... 

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