Process Technologies

PRU (Propylene Recovery Unit)

Axens Propylene Recovery Unit (PRU) processes LPGs that typically come from FCC or Coker units to produce a stream of high purity propylene suitable for petrochemical applications. Additional complex refinery or petrochemical purge streams containing propylene may also be treated.

The design is customized in order to fulfill the required propylene specifications, frequently chemical, chemical high purity or polymer grades or even custom specifications, with purities of up to 99.8 wt%.

Propylene impurities such as water, sulfur compounds, phosphine or arsine are removed through the use of specific Axens’ adsorbents (AxSorb® and AxTrap™), involving fully automated regeneration if necessary.

Sulfrex™

The extractive Sulfrex™ process eliminates mercaptans and reduces the total sulfur concentration. With its mild operating conditions of pressure and ambient temperature, this continuous process is ideal for C₃, C₄, LPG, light gasoline and NGL feeds.

Sulfrex™ covers several configurations:

• Olefinic LPG ex FCC, Coker and Visbreaking
• Non Olefinic LPG on saturated distillations columns, or from hydrotreating units
• Gas field NGL

Axens does not impose any proprietary equipment as extractor trays, mixers, filters, contactors, coalescers and oxidizer internals. This results in a lower initial unit cost and also a lower maintenance cost when replacing such equipment.

Olicrack™

Olicrack™ is a process to bridge the petrochemical-refinery gap to convert unwanted or lower valued olefins into propylene and ethylene. The process combines olefin Oligomerization and cracking in a single reactor using a selective zeolite catalyst and continuous catalyst regeneration system.

The purpose of the Olicrack™ unit is to produce a high quantity of propylene, through oligomerization and cracking of primarily C₄ to C₆ olefin-rich feeds, using a zeolite-based catalyst. The aim of the Olicrack™ process is to improve low value feedstocks such as off-gas, LPG purges or light ends through the production of propylene and, to some extent, ethylene.

HS-FCC™

An alliance involving Saudi Aramco, ENEOS, King Fahd University of Petroleum and Minerals, Technip Stone & Webster Process Technology and Axens Solutions has led to the development of the HS-FCC™ process which is able to produce up to 25 wt% propylene by converting heavy hydrocarbon feedstock under severe FCC conditions.

The main features of the HS-FCC™ process are:

• A down-flow reactor
• High reaction temperature
• Short contact time
• High catalyst to oil ratio (C/O)

The HS-FCC™ process operates at high temperature and high C/O ratio but with a short contact time in order to promote catalytic cracking, enhancing thus the yield of propylene.

FlexEne™

Axens has developed the new FlexEne™ technology to expand the capabilities of the FCC process which is the main refinery conversion unit traditionally oriented to maximize gasoline and at times propylene production.

FlexEne™ is an innovative combination of two well-proven technologies: Fluidized Catalytic Cracking (FCC) and Oligomerization (Polynaphtha™). Combined in an innovative way, they can significantly improve product flexibility to control the balance of propylene, gasoline and diesel production with a low capital investment. This FLEXibility is achieved by selective oligomerization of light FCC alkENEs (olefins) for recycle cracking in the FCC.

By adjusting the catalyst formulation and operating conditions, the FCC process is able to operate in different modes: Maxi Distillate, Maxi Gasoline and High Propylene. This provides the product flexibility required by the market.

R2P™ (Resid to Propylene)

Axens has developed Resid to Propylene (R2P™) for residue feeds to produce 8-13 wt% propylene. When the process objective is maximum propylene production, specific technology features must be added to the FCC/RFCC unit. The challenge is particularly great when the feedstock contains residue.

Depending on the quality of the feed and the propylene and other product targets, Axens can develop customized solutions for:

• Maximum LPG and Gasoline or "High Propylene"
• Maximum Propylene

High Propylene FCC

Axens has developed High Propylene FCC (HP FCC™) for traditional distillate feeds to produce 10-15wt% propylene. Depending on the quality of the feed and the propylene and other product targets, Axens can develop customized solutions for:

• Maximum LPG and Gasoline or "High Propylene"
• Maximum Propylene
• Maximum Distillate & LPG

R2R™

The Reactor-2-Regenerator (R2R™) design was developed to specifically meet the challenge of heavy resid processing.

The unique two-stage regeneration system permits safe regeneration of catalyst containing high levels of metals, principally vanadium that would otherwise rapidly deactivate the catalyst.

Key advances incorporated in the design include:

• Best available feed injector technology
• Riser temperature control with MTC
• Catalyst mixing control with SCM technology
• RS2™ high containment riser separation system
• Vapor quench technology for high severity operation
• Superior catalyst stripping with structured packing

VGO FCC

The reaction system is the heart of the process and is defined from the point of catalyst introduction into the riser to the catalyst discharge from the stripper. The entire system needs to be designed to work in concert to maximize performance for maximum distillate, gasoline or LPG production.

HyC-10™

In HyC-10™, the mild hydrocracking units (MHC) diesel receives the entire H₂ make-up needed for both reaction sections and is sent to a polishing reactor operated in once-through mode. In addition, HyC-10™ systems can be designed to co-process other difficult feedstocks present in the refinery such as LCO, light cracked GO and visbroken GO (HyC-10+ process).