BOTTOM OF THE BARREL UPGRADING

The atmospheric and vacuum residue (AR/VR) hydrotreater is a key refinery unit which improves residue feeds for fluid catalytic cracking (RFCC) units and which produces additional diesel as well as low sulfur fuel oil.

Residue hydrodesulfurization units (RDS) improve downstream conversion operations by eliminating difficult feed components thus enabling the refinery engineers to squeezing the most out of the bottom-of-the-barrel, and maximize profitability.

Hyvahl unit with Permutable Reactor System (PRS)

Our unique portfolio for AR/VRDS processing is highlighted by the Hyvahl technology and a full range of advanced resid hydrotreating catalysts.

HYVAHL: THE IDEAL RFCC PARTNER

Hyvahl is a high performance RDS process with a perfect commercial operation safety record. It has been employed both for improving residue quality for use as an FCC feed and for the production of ultra low sulfur fuel oil (ULSFO).

Hyvahl technology features: • can process AR/VR blends or 100% VR with high

metals content • attains the most stringent ULSFO specifications

with sulfur content as low as 0.28 wt % (Middle

East crude) throughout long cycle lengths • typical conversions range from 15 to 25 wt% • produces low sulfur diesel • produces an excellent RFCC feed:

o very low sulfur content o low metals (Ni and V) content o low Conradson Carbon Residues (CCR) o improved hydrogen-to-carbon mole ratio.

PROCESS DESCRIPTION

The residue feed and hydrogen are pre-heated then fed into the reactor section. Upgrading begins with a Permutable guard-bed Reactor System (PRS) to eliminate undesirable metals through hydrodemetallization (HDM), followed by a transition section and the final hydrotreating section for hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and CCR reduction through hydrotreating (HDCCR).

The PRS section protects the downstream catalysts by removing or converting a sizeable portion of sediment, metals, and asphaltenes from the feed. These materials would otherwise foul, plug, or deactivate the downstream catalysts, thereby severely reducing performance of the RFCC unit.

R1A R1B

PRSGuard Reactors

HDMDemetallization

Conversion

HDSDesulfurization

Refining

To GasTreatment

ToFractionatio

SectionResidue Feed

Hydrogen

HDMHDS

Transition

Simplified Hyvahl process flow diagram

Hyvahl™ HIGH PERFORMANCE FIXED-BED ATMOSPHERIC AND VACUUM RESIDUE HYDROTREATING

The transition section completes the demetallization process and initiates the deep hydrotreating phase. The transition catalyst has dual function characteristics that are between those found in the HDM and the hydrotreating sections with respect to demetallization and refining.

With most major contaminants removed at the outlet of the transition section, the residue is sent to the final refining section, where sulfur and CCR levels are reduced to the very low design specifications. The reactor section effluent is then fractionated into naphtha, diesel and hydrotreated residue. Optimally, a vacuum tower can be added to recover the hydrotreated VGO fraction which is sent directly to the FCC unit without any additional treatment.

TAILORED RESID CATALYST SYSTEM

The types and quantities of catalysts in each Hyvahl reactor are carefully selected to achieve the desired unit performance. The latest generation hydrotreating catalysts produced from our ACE (Advanced Catalyst Engineering) manufacturing process are specially designed for the Hyvahl process to ensure: • strong HDM and pressure drop management in

the PRS section (HF 858 catalyst and ACT grading materials)

• HDM finishing and HDS in the transition zone (HM 848), and

• high HDS, HDN and HDCCR in the refining reactors (HT 438 catalyst)

Additional information is available in separate commercial bulletins concerning Advanced Residue Hydrotreating Catalysts and Grading Materials.

PERMUTABLE REACTOR SYSTEM (PRS)

The PRS is a proprietary, safe and cost effective solution for increasing RDS on-stream factor. This unique commercial design combines the high efficiency of fixed-bed catalysis and special valves noted for their dependability and safety. This combination enables the high on-stream factor obtained with Hyvahl when operating on residue feeds rich in metals, asphaltenes and sediment. PRS can be put on-line and taken off-line for catalyst

replacement without shutting the main reactors down using “lead/lag” operation.

Hyvahl

Main ReactorSection

Main ReactorSection

GuardReactor

R1B

GuardReactor

R1B

GuardReactor

R1A

GuardReactor

R1A

Permutable Reactor System

(PRS)

Permutable Reactor System

(PRS)

Reactor arrangement with the PRS section in a Hyvahl unit

For many feedstocks and refinery objectives, PRS offers incomparable advantages over other fixed- or moving-bed technologies: • longer cycles without any premature shutdowns

due to pressure drop limitations • more efficient HDM and HDS catalyst utilization • higher flexibility to process heavier feeds

including 100% VR feedstock • no catalyst attrition as observed for moving-bed

designs • constant effluent quality throughout the cycle • lower CAPEX compared to single HDM reactor

configurations • smaller HDM catalyst volumes PRS can be implemented on existing RDS units for revamping or debottlenecking with the possibility to process feedstocks with higher metals, asphaltenes and sediment contents.

HOW DOES THE PRS WORK?

In a conventional fixed-bed RDS unit, the catalyst in the guard reactor carries out the HDM function to protect the downstream HDS catalyst. Feed impurities are deposited on the bed, limiting run lengths to a few months. The upstream reactor is the first to undergo bed plugging, pressure drop build-up, and catalyst deactivation.

In a substantial number of cases, pressure drop increase results in premature unit shutdowns. At the same time, catalyst deactivation is compensated by increasing temperature to achieve yield and product qualities. The metal retention potential of the guard reactor catalyst determines when metals break through, thus poisoning the downstream refining and RFCC catalysts. A conceptual flow scheme of the PRS is illustrated below:

Atmosphericor Vacuum Residue

to HDSand Refining

Section

R1A R1BR1ALow P

CatalystConditioning

Section

Low PCatalyst

ConditioningSection

R1B

Permutable Reactor System Flow Scheme

Before entering the transition reaction section, the feed flows through the PRS (arranged in series), which is composed of a lead (R1A) and a lag-guard reactor (R1B). R1A and R1B take out the bulk of the feedstock metals and sediment, providing a cleaner feed to the downstream section which completes HDM and begins the HDS process. Whenever possible, both R1A and R1B operate in series. Sampling systems are used for monitoring reactor effluent quality. The novelty of PRS resides in the safety features that enable R1A to be taken off-line for catalyst change-out, while R1B continue to operate. Each PRS reactor can be isolated from the main section using high-pressure motorized valves. PRS also includes a low-pressure catalyst

conditioning section to enable catalyst replacement and activation independently without affecting normal operations. During the run, pressure drop in R1A increases and the catalyst deactivates. When constraint limits are attained, R1A is isolated from RDS operation, cooled and depressurized. Spent catalyst is discharged, then fresh catalyst is loaded and activated before R1A is put back on-line in the lag position. During the change-out period, R1B operates alone, and maintains high HDM activity.

CONSTANT PRODUCT QUALITY AND LONGER CYCLE LENGTH WITH PRS

The benefits of the PRS technology are quite frankly enormous. Demonstrated below is the case of a typical commercial operation between RDS change-outs:

Conventional RDS unit without PRS

RDS unit revamped with PRS

Catalyst replaced in all reactors

EOR

EOR

R1A + R1B R1B R1B + R1A R1A + R1BR1A

0 t 1.6 x t

R1A catalyst replacement 15-20 days

R1B catalyst replacement 15-20 days

Comparison of RDS cycle lengths without and with PRS

The top diagram shows the operation of a conventional RDS unit which proceeds continuously until the end of run (EOR), defined as time “t”, when the catalysts in all reactors are changed-out simultaneously. The lower diagram shows the operational sequence of the revamped unit where the PRS provides a prolongation the overall operation of the unit, thereby allowing a 60% gain in run length between unit shutdowns. Moreover, PRS enables the same volume of HDS catalyst to treat much more feedstock with the production of better quality hydrotreated residue as illustrated in the following table.

Jan.

11-H

yvah

l

Hydrotreated residue characteristics

Conventional RDS unit before

revamping

Revamped RDS unit with PRS

Sulfur, wt %:

SOR 0.5 0.4

EOR 0.55 0.4

Conradson Carbon, wt %:

SOR 4 3

EOR 4.5 3

Metals (Ni+V), wt ppm:

SOR 8 6

EOR 12 6

Impact of PRS on RDS product quality

IMPACT ON RFCC PERFORMANCE

Improving residue feed quality to the RFCC unit, with Hyvahl or with a PRS revamp on a conventional RDS unit, affords major RFCC benefits: • improved overall conversion and RFCC operation • increased gasoline and propylene yields • reduced coke and slurry yield • direct production of low sulfur gasoline • reduced SOx and NOx emissions • significantly reduced RFCC catalyst consumption

due to lower catalyst poising by metals and deactivation by asphaltenes

A commercial case study has shown that the addition of a PRS section to a conventional RDS unit reduces RFCC catalyst consumption by 1,800 tons per year due to the lower metal content in the RFCC feed.

KEY PROCESS FEATURES

For a wide range of AR/VR feeds, the Hyvahl process offers a unique combination of advanced solutions: • Innovative Permutable guard-bed Reactor System

(PRS) featuring a unique valving system and an unmatched safety record, specially designed for high metals or sediment containing feeds

• near-perfect fluid distribution with our EquiFlow® reactor internals

• exceptionally active and stable catalysts manufacturing with the ACE® (Advanced Catalyst Engineering) process

Compared with conventional processes, Hyvahl has clear advantages of longer cycles, safe operation and stable product quality even with 100% VR feedstock.

COMMERCIAL EXPERIENCE

Three Hyvahl units processing AR and VR feeds are currently in operation and represent more than 20 years of cumulative operation.

Four additional Hyvahl units designed with PRS have been awarded over the last three years. These units are at various stages of detailed engineering or construction.

This is what one of our key clients said about Hyvahl:

… We have been producing several kinds of residue product from below 0.3 wt % sulfur to 0.5 wt % sulfur, depending on the market and refinery condition, safely and in one year cycles. Concerning the PRS section, we have replaced the guard HDM catalyst 29 times in 10 years in our #1 Hyvahl unit. There have not been any operational problems nor any safety issues …

Head of Engineering Dept.

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