# Revamping Fluid Catalytic Cracking Unit, and Optimizing Catalyst to Process Heavier Feeds
## 2 Materials and Methods  
The properties of the vacuum gas oil feedstock streams (straight-run hydrotreated VGO; H-Oil heavy atmospheric gas oil (HAGO); H-Oil light VGO (LVGO); and H-Oil heavy VGO (HVGO)) feeding the LNB FCCU under study are summarized in Table 1. \begin{table}
\begin{tabular}{c c c c c c} \hline
**FCC Feed Properties** & **Methods** & **SRHTVGO** & **H-Oil HVGO** & **H-Oil LVGO** & **H-Oil HAGO** \\ \hline Density at 15 \({}^{\circ}\)C, g/cm\({}^{3}\) & ASTM D 4052 & 0.9014 & 0.9784 & 0.9639 & 0.9393 \\ Sulphur, wt.\% & ASTM D 4294 & 0.1763 & 0.67 & 0.48 & 0.37 \\ Nitrogen, wt.\% & ASTM D 5762 & 0.08 & 0.25 & 0.32 & 0.21 \\ Basic nitrogen, mg/kg & UOP269 & 393 & 819 & 1070 & 686 \\ Conradson carbon, wt.\% & ASTM D 189 & 0.24 & 2.67 & 0.34 & 0.15 \\ Refractive Index, 60 \({}^{\circ}\)C & ASTM D 1747 & 1.499 & 1.551 & 1.540 & 1.521 \\ C\_Aromatics, wt.\% & ASTM D3238 & 24.4 & 41.3 & 43.6 & 38.7 \\ C\_Paraffins, wt.\% & ASTM D3238 & 60.1 & 48.6 & 47.6 & 50.7 \\ C\_Naphthenes, wt.\% & ASTM D3238 & 15.5 & 10.1 & 8.9 & 10.7 \\ Molecular Weight, g/mol & VPO & 396 & 416 & 323 & 296 \\ \hline \end{tabular}
\end{table} 
Table 1: Properties of the FCC feed streams studied in this work. The properties of the catalyst employed at the LNB FCCU before and after the revamp (catalyst G), and that of the selected, most active and coke-selective catalyst, designated as catalyst H, to employ in the LNB FCCU after the revamp are presented in Table 2. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**FCC Feed Properties** & **Methods** & **SRHTVGO** & **H-Oil HVGO** & **H-Oil LVGO** & **H-Oil HAGO** \\ \hline Sim. Dist., \({}^{\circ}\)C & ASTM D & & & & \\  & 2887-extended & & & & \\ IBP & & 287 & 213 & 254 & 234 \\
5\% wt. & & 353 & 395 & 316 & 300 \\
10\% wt. & & 371 & 416 & 336 & 322 \\
50\%wt. & & 444 & 484 & 403 & 373 \\
90\% wt. & & 529 & 541 & 479 & 433 \\
95\% wt. & & 556 & 556 & 503 & 455 \\ FBP & & 595 & 555 & 517 \\ Kow-factor & & 12.10 & 11.61 & 11.48 & 11.53 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 1: Laboratory tests with six catalyst candidates to select the most active (**a**) and coke selective (**b**) catalyst to employ in the revamped FCC unit. The conversion was estimated as 100-LCO-HCO-Slurry, wt.%  
Where, LCO = light cycle oil yield, wt.%; HCO = heavy cycle oil yield, wt.%; and Slurry = slurry oil yield, wt.%. The main technical and technological problems in the LNB FCCU before the revamp were:  
High catalyst losses;  
Increased APS of equilibrium catalyst (from 90 to 108 \(\upmu\)m). Reduction in the content of the catalyst working fraction (20-80 \(\upmu\)m decreasing from 39 to 19%) in the catalyst composition [36];  
High temperatures in the regenerator [34];  
Shortage of regeneration air;  
Unsatisfactory condition of reactor and regenerator lining of internals;  
Exhausted service life of internal devices. Loss of conversion;  
Low yields of target products (gasoline, BBF, PPF, LCO);  
High olefin content in FCC gasoline;  
Increased catalyst \(\Delta\) coke;  
Low catalyst circulation;  
Unstable \(\upmu\)p of regenerated and spent catalyst valves at high throughput. To limit the negative effects of a degraded feedstock quality, the FCCU operated at a load of 240 t/h (design capacity, 250 t/h) [34]. In late 2021, a revamp of the FCCU was carried out, the main objectives of which were:  
Adaptation of the FCCU to the processing of heavier vacuum gas oils from H-Oil;  
Increasing the mechanical reliability of the equipment by replacing the internal devices in the reactor and regenerator, which were significantly depreciated with expired service life. Reducing catalyst losses from the reactor and regenerator cyclone systems. Improvement in the environmental situation. In our earlier research [37], a process diagram of the whole LNB FCCU is presented. During the revamp, only the FCC reactor-regenerator section was modified. The modifications of the reactor-regenerator section made during the revamp are presented in Figure 2.