Feb-2024

Combining Prime-G+® and GT-BTX PluS™ to upgrade a refinery with crucial operating flexibility (TiA)

The landscape of the petroleum refining industry has undergone a significant transformation in the aftermath of the global pandemic.

Charlie Chou, Sulzer Chemtech
Mina Basta, Axens

Article Summary

The volatile and unpredictable nature of market demands post-pandemic has underscored the critical importance of adaptability for refineries. In this rapidly evolving environment, the ability to swiftly adjust production focus to meet changing market requirements has become paramount. The integration of Prime-G+ and GT-BTX PluS technologies offers refineries a unique solution to address these challenges by providing built-in operating flexibility.

Challenges of current refineries
Modern refineries are divided between those that emphasise fuel production, particularly gasoline, and those that prioritise the maximisation of petrochemicals output. For gasoline-focused refineries, the octane number is a key determinant of profitability, with even marginal improvements translating to substantial gains. In developing countries, refineries are compelled to elevate gasoline specifications to meet Euro-5 standards while simultaneously reducing sulphur levels to <1 ppm. The challenge lies in maintaining octane numbers while achieving such stringent sulphur reduction. Meanwhile, petrochemical-centric refineries seek efficient ways to convert gasoline into high-value petrochemical products while minimising investments.

Combined technology in gasoline mode for gasoline production with max profitability
The amalgamation of Prime-G+ and GT-BTX PluS technologies introduces an innovative approach that yields impressive benefits. This combination entails the installation of a new GT-BTX PluS unit alongside an existing Prime-G+ unit 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 selective hydrotreating unit (SHU), leaving light cracked naphtha (LCN) that has high-octane olefins but low sulphurs, and heavy cracked naphtha (HCN) that has low olefin content 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 components 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 retention 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 consumption, 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 valuable 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 (HDS) in the Prime-G+unit, culminating in a high-quality petrochemical BTX product (benzene, toluene, xylenes). Furthermore, the olefin-rich non-aromatics raffinate stream derived from GT-BTX PluS proves invaluable for FCC recycling, producing significantly additional propylene and enhancing the FCC propylene yield. Alternatively, if aromatics is the focused product, this raffinate can be routed to a fixed-bed GT-Aromatization unit, coupled optionally with LCN, driving substantial BTX production. Figure 4 shows the mentioned two options of combined technology in the petrochemical mode for converting a significant portion of FCC gasoline into petrochemical products.

Operating flexibility of the combined technology
The true strength of the Prime-G+ and GT-BTX PluS integration lies in its exceptional operating flexibility. Refineries can seamlessly switch between gasoline-focused and petrochemical-centric modes of operation. This adaptability is crucial as market demands oscillate, necessitating rapid shifts in production focus. By adopting this combined technology, refineries across diverse regions gain the agility to swiftly align their production strategy with prevailing market requirements.

Summary
Incorporating the combined Prime-G+ and GT-BTX PluS technologies is a transformative investment for refineries. This single investment affords refineries the dual capability to optimise both gasoline and petrochemical production, irrespective of ever-fluctuating market dynamics. The intrinsic operating flexibility enables refineries to pivot their focus instantly, whether the demand is for gasoline or petrochemicals. In an industry where adaptability is synonymous with success, the Prime-G+ and GT-BTX PluS integration emerges as an indispensable asset for all FCC-equipped refineries. By embracing this technology, refineries can confidently navigate the intricate landscape of post-pandemic refining, reaping significant benefits and securing a competitive edge.

Incorporating the combined Prime-G+ and GT-BTX PluS technologies is a transformative investment for refineries. This single investment affords refineries the dual capability to optimise both gasoline and petrochemical production, irrespective of ever-fluctuating market dynamics. The intrinsic operating flexibility enables refineries to pivot their focus instantly, whether the demand is for gasoline or petrochemicals. In an industry where adaptability is synonymous with success, the Prime-G+ and GT-BTX PluS integration emerges as an indispensable asset for all FCC-equipped refineries. By embracing this technology, refineries can confidently navigate the intricate landscape of post-pandemic refining, reaping significant benefits and securing a competitive edge.

GT-Aromatization and GT-BTX PluS are trademarks of Sulzer Chemtech. Prime-G+ is a  trademark of Axens.

This short case study originally appeared in PTQ's Technology In Action Feature - Q1 2024 Issue

For more information: Livia.Fallet@sulzer.com