LCN
Ole n distribution
LCN
MCN
HCN
MCN
FCC/RFCC Naphtha
SHU
70–150˚C
(Olen-rich)
Hydrogen
C
C
C
C
C
C
HCN
150˚C - EP
(Olen-lean)
Figure 2 Fractionation of FCC gasoline for the combined technology
if present or grassroot of both technologies if there is no FCC gasoline hydrotreating yet. The GT-BTX PluS unit, a cost-effective two-column extractive distillation system, facilitates the extraction of sulphur from the FCC gasoline, preserving olefins in the raffinate stream with less than 10 ppm sulphur. The indicative configuration of the GT-BTX PluS unit is illustrated in the Figure 1 . To implement the combined technology, middle cut naphtha (MCN) that contains high-octane olefins and high sulphurs is purposely fractionated after Prime-G+’s selec- tive hydrotreating unit (SHU), leaving light cracked naph- tha (LCN) that has high-octane olefins but low sulphurs, and heavy cracked naphtha (HCN) that has low olefin con - tent but high sulphurs. Such fractionation is illustrated in Figure 2 . With such fractionation, the high-octane olefin-rich and low-sulphur LCN will be sent to the gasoline pool. The high-olefin and high-sulphur MCN will be processed in the GT-BTX PluS unit, where the sulphur and olefin com - ponents will be separated to the extract and raffinate, respectively, as illustrated in Figure 1. At the combined
technology’s gasoline mode, the preserved raffinate can be blended into the gasoline pool, contributing to the reten- tion of olefins and octane numbers, even in compliance with Euro-5 ultra-low sulphur standards. Meanwhile, the extract with concentrated sulphurs but nearly no olefins will be combined with HCN to be hydrodesulphurised by Prime-G+’s HDS without worrying olefin saturation. The configuration of this combined technology is shown in Figure 3 . Notably, this configuration virtually eliminates octane loss while significantly reducing hydrogen con - sumption, culminating in a refinery’s peak profitability in Euro-5 gasoline production. Combined technology in petrochemical mode for gasoline-to-petrochemicals The same combined technology of Prime-G+ and GT-BTX PluS unveils an avenue for converting gasoline into valu- able petrochemical products. In its petrochemical mode with the same configuration, the GT-BTX PluS extract, a nearly pure aromatic stream with sulphur being the only impurities, undergoes intensified hydrodesulphurisation
LCN
P O N
A S
P O N
Extraction (GT-BTX PluS)
Ra nate <10ppm S
MCN
FCC/RFCC Naphtha
ULS gasoline
SHU
A S
Extract
Hydrogen
HDS
HCN
<10ppm S
Hydrogen
Figure 3 Configuration of the combined Prime-G+ and GT-BTX PluS technology in gasoline mode
98
PTQ Q1 2024
www.digitalrefining.com
Powered by FlippingBook