Hydrocarbon Processing - January 2021 - 27

Special Focus

Sustainability
M. HALVACI, E. A. SUBAIE and N. A. FUDHAIL,
Saudi Aramco, Dhahran, Saudi Arabia; and C. PIERRE
and E. ROUSSEAU, Axens, Rueil-Malmaison, France

Ras Tanura: The creation of a clean-fuels complex
The primary objective of the Ras Tanura Refinery Clean
Fuels Project is to enable the Ras Tanura refinery-the largest refinery in Saudi Arabia-to produce transportation fuels
that will be compliant with future specifications. The project
targets the ability to produce gasoline and diesel products to
Euro 5 specifications, as well as to maximize refinery gasoline production, especially through the utilization of Khuff
gas condensate naphtha. The scope of the project is to install
new process units that provide flexibility for maximizing fuels
production in the near term, while being able to transition to
petrochemical production in the future.
The Ras Tanura refinery is a major gasoline producer in the
Middle East. It can produce up to 170,000 bpd of gasoline,
primarily using reformate from its three reforming units. It operates one continuous catalyst regeneration (CCR) reforming
unit and two fixed-bed semi-regenerative reformers. Due to
the use of the fixed-bed reformers, the reformate pool tends
to have high levels of benzene. Mitigation measures to reduce
these levels (e.g., cut point adjustments) are insufficient to adhere to upcoming clean fuels specifications. This is especially
problematic when trying to maximize gasoline production.
The refinery's naphtha supply also exceeds the current reformer capacity. Under the previous specifications, the relatively low sulfur content of the Khuff naphtha allowed for direct inclusion into the gasoline pool. This naphtha inclusion
provided for a means to dilute the benzene and aromatics of
the reformate pool. The lower sulfur levels mandated by the
new specifications no longer allow this practice to continue. In
the future, even these lower sulfur naphtha streams must also
be desulfurized to be included in the gasoline pool.
At the early stages of project development, it was decided to replace the two fixed-bed reforming units with a new,
larger CCR reforming unit. The new CCR reformer was to
be designed primarily to process Khuff condensate naphtha. Additionally, the project was to maximize the octane
(through isomerization) of the large, light-naphtha stream
that was also available.
The selected approach was to install a world-scale naphtha
reforming complex consisting of a naphtha hydrotreating unit,
a CCR reforming unit and an isomerization plant. The nearterm objective was for the reformer to produce a low-benzene
reformate stream. With the availability of other relatively
high-octane streams, including the new isomerate, it would
be possible to operate the reformer at a relatively low severity
for total aromatics control in the gasoline pool. The reforming

unit was to also have the ability to maximize aromatics-particularly mixed xylenes-in the future.
Clean fuels complex. Saudi Aramco is building a world-scale
clean fuels complex at the Ras Tanura refinery. The process
units' capacities are to be some of the largest in the world. For
example, the complex will include a 140,000-bpd naphtha hydrotreating unit, a 90,000-bpd CCR reforming unita (FIG. 1) and
a 65,000-bpd C5-C6 isomerization unit. The CCR reforming
unit will initially be configured for refinery gasoline production
but could also be reconfigured for aromatics production for use
in petrochemical production. A simplified blockflow diagram of
the CCR reforming unit is shown in FIG. 2.

FIG. 1. View of the CCR reforming unit under construction at the
Ras Tanura refinery.
Hydrocarbon Processing | JANUARY 2021

Hydrocarbon Processing - January 2021

Table of Contents for the Digital Edition of Hydrocarbon Processing - January 2021