Catalysis 2022 issue

the reformate octane. Conversely, the lower this index – that is, the higher the paraffins content – the higher the severity of operation required to meet the same product specifications. Recycle gas flow The highest severity operation increases the water and H 2 S content in the recycle gas, potentially harm- ing the catalyst. Hydrogen to hydrocarbon ratio The H 2 /HC ratio is the ratio of H 2 in the recycle (mole/hr) to the feed flow rate (mole/hr). The recycle H 2 is necessary for catalyst stability. The recycle H 2 sweeps the reaction prod- ucts and other condensable mate- rials from the catalyst and supplies the catalyst with H 2 . Hydrogen flow to first upper hopper for elutriation Elutriation gas (hydrogen) flow to the first upper hopper is used to sieve out the dust and fine particles. The ideal case is to collect about 0.5- 1.0 kg of catalyst dust per day. It might be noted that a sample has been collected from the central pipe, and it has confirmed that the broken material is CCRU catalyst. The analysis is shown in Table 2 . Figures 3 and 4 show the differ - ence between the normal catalyst and broken catalyst structure with 500 μm magnification. It is worth mentioning that although the design RON of CCRU is 101 and the assets may be capa- ble of processing higher severity, the unit was restricted due to cata- lyst attrition when s RON increased from 95 to 98. Fresh catalyst is expected to behave in a more con- trollable manner. Conclusion As obtained from the linear regres- sion analysis, the high increase in first reformer reactor ∆P is observed when operating with high RON from 95 to 98. This is influenced by several factors, mentioned above, which eventually increased the cat- alyst attrition and, in turn, the high pressure drop. It might be noted that the model gets R 2 = 91.96%, showing the sig-

Fitted line plot y = -6.224 + 0.01263 X6

0.5

0.0575775

R-Sq 51.1% R-Sq(adj) 51.0%

0.4

0.3

0.2

0.1

0.0

495

500

505

510

515

520

525

Figure 2 RON control temperature and the first reformer reactor ∆P

Figure 3 Normal catalyst magnification

Figure 4 Broken catalyst magnification

where N and A are the liquid vol - ume per cent of naphthenes and aromatics are used to characterise the feed. The higher this index, the lower the severity required to attain

dust), especially after almost 245 cat- alyst regeneration cycles. Broken catalyst particles were trapped between the vertical wires of the central pipe, obstructing the open area. These particles then start accumulating to form a cake around the central pipe. At this point, the first reformer reactor ∆P starts to increase significantly. The pressure drop can take 3-4 months to reach 1 kg/cm 2 , necessitating unit shutdown to clean the reactor central pipe. Unit feed The reformer feed consists of paraf- fins, olefins, naphthenes, and aro - matics (or PONA). The reforming index can be defined as (N+2A),

Sample analysis collected fromfirst reformer reactor central pipe

Element

Result

Al 2 O 3 , wt%

83.04 0.113 0.475 0.196 0.365 0.391

Fe Ca Sn Pt

Carbon by LECO, wt% Chloride by CIC, wt%

7.15 0.71

Table 2

32 Catalysis 2022