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What AI and data analysis techniques do catalyst and reactor technology developers offer refiners for higher yields while meeting near-zero emissions specifications?

Mar-2024

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Ray Fletcher, Gasolfin BV, rfletcher@inovacat.com

The role of olefins is fundamental to industry today and is the focus of this response. Inovacat believes that this question is best addressed in three distinct phases. Phase One addresses the immediate future, extending over the next three to five years. Phase Two addresses the medium-range future of the next 15-20 years. Phase Three refers to post-2040 operations.

Phase One will be achieved through naphtha and propane conversion assets presently being operated by refiners today, namely FCC and PDH operations for maximum propylene and steam crackers for maximum ethylene. The FCC propylene yield may be increased via changes to the base catalyst, ZSM-5 additives, and operating the FCC at increased severity. The FCC catalyst may be optimised by reduced rare earth concentrations for reduced hydrogen transfer reactions and with increased zeolite content for activity retention.

The PDH unit will require operating at an increased feed rate or debottlenecking. The steam cracker propylene yield is dependent upon the amount of light straight run naphtha (LSR) being charged to the unit. Steam crackers currently feeding LSR to the unit may consider increasing the fresh feed rate by debottlenecking the charge heater. This may be achieved if a portion of the pentane recycle was removed from the feed slate, assuming an alternative outlet for pentane is found. It is believed that most refiners intending to begin, or those continuing the transition from fuels to petrochemicals will have already made these changes and so may be limited in the extent of further olefin production.

Phase Two begins soon and extends for the following 15-20 years. The transition from fuels to petrochemicals is expected to continue with the larger declines observed with gasoline, marginal declines in diesel, and increases in jet fuels.¹ At the same time, refiners need to reduce greenhouse gas (GHG) emissions to achieve 2030/2050 targets.

Alternative technologies include options such as high severity FCC, shifts from FCC towards hydrocracking and steam cracking, and many others. Fundamental changes may also be possible with crude-to-chemicals technologies being developed, such as Lummus’ Thermal Crude to Chemicals (TC2C) technology. The negative side of these options is the high costs and construction time.

Inovacat’s Gasolfin technology fits well into all Phase Two options. The Gasolfin catalyst system converts naphtha boiling range molecules into light olefins (ethylene, propylene, and butylene) with total olefin yields up to 88 wt%. Olefin yields are up to 27 wt% ethylene, 46 wt% propylene, and 30 wt% butylene, depending upon feedstock (see Figures 1 and 2).

The Gasolfin catalyst cracks pentane into 32 wt% propylene. This technology has been under development since 2017 in conjunction with the Chemical Process and Energy Resources Institute (CPERI) laboratory in Thessaloniki, Greece. An alternative outlet for naphtha is expected to be a challenge for profitable refinery operations. Gasolfin is a naphtha conversion technology, producing light olefin with significantly lower CO₂ emissions than the three leading propylene-producing technologies: FCC, steam cracking, and propane dehydrogenation.

A paper for benchmarking GHG emissions for existing technologies is entitled Energy and GHG Reductions in the Chemical Industry via Catalytic Processes.²,³ Gasolfin produces 0.45 tons of CO₂ for every ton of total olefin produced, which is annotated as ‘tCO₂/tHVC’, where tHVC abbreviates ‘ton Highly Valued Chemical’. The HVC definition for Gasolfin is the sum of ethylene, propylene, and butylene. HVC for PDH and FCC is propylene and ethylene for steam cracking. This excellent metric enables a side-by-side comparison of an FCC and a steam cracker.

GHG reductions place the GHG emissions of an FCC between 0.783 and 0.869 tCO₂/tHVC. A steam cracker processes naphtha at 0.700 and ethane at 0.964 for an average GHG emissions level of 0.832 tCO₂/tHVC. A PDH unit produces 1.231 tCO₂/tHVC (see Figure 3).

Inovacat has completed bench-scale and pilot plant testing of this technology and is currently finalising the front end engineering design (FEED) study for a demonstration unit to be operated at an Asian refinery. The demonstration plant will start operations in early 2025 to commercialise the technology in 2027. Gasolfin is in fundraising mode to finance this programme up to commercialisation.

Phase Three includes post-2040 operations to achieve 2050 targets of net zero emissions and beyond. The technologies currently under development include bio-based olefins via gasification of bio-feedstocks. A disadvantage is that these technologies currently do not always scale well. Another possible route is e-fuels and e-olefins through e-methanol. The advantage is that they scale well but are not yet mature. The profitability of these routes has not yet been proven.

The next several decades should prove to be interesting in terms of managing the expected declining naphtha demand while continuing to meet the olefin production requirements. We are fortunate to be able to play a role in these critical years to come.

References
1 Fitzgibbon T, Simmons T, Szarek G, Varpa, S From Crude Oil to Chemicals: How Refineries Can Adapt to Shifting Demand, McKinsey & Company.
2 Energy and GHG Reductions in the Chemical Industry via Catalytic Processes: Annexes; International Energy Agency, International Council of Chemical Associations, Dechema, 2013, pp17-21.
3 Dziedziak C R, Murphy J J, Olefin production pathways with reduced CO₂ emissions, PTQ Q3 2023, pp39-47.

Apr-2024
Mark Schmalfeld, BASF Refining Catalysts, mark.schmalfeld@basf.com

Over the coming decades, global market demand for refined products is expected to shift. Fewer transportation fuels will be needed (primarily gasoline as the market shifts to electric vehicles) while we see an increased demand for naphtha, olefins, and other petrochemical feedstocks. Also, besides the global trends, each refiner’s profitability can depend heavily on the regional economics, regional product demand, and integration setup to enable the use of petrochemical feedstocks (internal to the refinery or to supply to local customers).

No specific catalyst or reactor technology in the market has emerged as the only option, but there are market-leading processes in use today. Steam cracking is still one of the largest unit operations to produce ethylene and propylene from naphtha. The FCC unit is generally considered the second-largest unit operation to produce propylene. Additionally, we see many processes supporting the market need with a variety of private licensors and governmental licensor designs introduced. These licensor designs include improvements to the FCC unit, modifications to the FCC unit approach (deep catalytic cracking [DCC], HS-FCC, residue fluid catalytic cracking unit [RFCC], INDMAX) to shift selectivity to chemicals, new integrated refinery design for crude oil to chemicals, steam cracker improvements, and other unit improvements (reforming units, propane dehydrogenation [PDH] units, methanol-to-olefin processes, and others).

Each of these has specific process conditions and/or specific catalysts targeted for the units (from market catalysts to proprietary catalysts, and diverse types of materials/ zeolites – ZSM-5 (MFI), SAPO-34, Beta (BEA) and USY/REY (FAU) type zeolites) to meet specific refiner’s petrochemical yield targets.

The BASF refinery catalyst team continuously focuses on understanding the new market needs to create technologies to support this transformation to create petrochemical feedstocks from the FCC and other refinery processes.
Besides a market demand shift, we are also seeing a shift to using more alternative feedstocks (renewables, pyoils, recycled materials) to reduce the carbon footprint. From an FCC catalyst standpoint, BASF has introduced technologies to address the need for more petrochemical feedstocks (propylene, olefins) and to support the use of alternative feedstocks in these processes. Today, BASF has examples of using FCC catalysts (maximum propylene solution) in commercial units to maximise propylene with both resid, VGO feedstocks and using alternative feedstocks. Additionally, in North America and the Middle East, we see commercial use of new catalysts (Fourte, Fourtune, Fortitude, and newer materials) to drive both propylene and butylene yields.

These catalysts help achieve both chemical and feedstock requirements for alkylation processes, supporting their fuel octane needs. The catalyst technologies needed for maximising petrochemical feed production from FCC units have emerged through rigorous research, development, and technology application improvements. From this work, BASF has found that FCC catalysts require an integrated design approach to the catalyst materials. Use of multiple catalyst zeolite types and different functional materials is essential for the best performance when targeting petrochemical feedstock production. Additionally, ensuring the flexibility of an FCC unit to accept changes to FCC catalyst formulation or to allow rapid adjustments in olefin additive (ZIP, ZEAL) use enables profit optimisation.

Fourte, Fourtune, Fortitude, ZEAL and ZIP are marks of BASF.

Apr-2024
Yoeugourthen Hamlaoui, AXENS, yoeugourthen.hamlaoui@axens.net

Modern refineries are divided between those that emphasise fuel production, particularly gasoline, and those that prioritise the maximisation of petrochemicals output. Petrochemical-centric refineries seek efficient ways to convert gasoline into high-value petrochemical products while minimising investments. In this context, Axens has developed several combinations of technologies to help refiners adapt their existing assets.

The combined proprietary 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 impurity, undergoes intensified hydrodesulphurisation (HDS) in the Prime-G+ unit, culminating in a high-quality petrochemical benzene, toluene, xylenes (BTX) product. 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.

Axens’ FlexEne technology is a low Capex approach that combines two well-established processes: fluidised catalytic cracking (FCC) and oligomerisation. Polynaphtha (awarded the Best Refining Technology 2023 by Gulf Energy Information Excellence) is the Axens oligomerisation technology dedicated to oligomerise olefins contained in the light cracked cut into higher value olefinic cuts, which can be used as high-octane gasoline or high cold properties kerosene or diesel fraction. This combination aims to enhance the capabilities of the FCC process, which is typically the main conversion unit in refineries and is generally oriented towards maximising gasoline and, occasionally, propylene production.

The innovation in FlexEne lies in its ability to significantly improve the flexibility of product output, allowing for better control over the balance of propylene, gasoline, and diesel production. This flexibility is achieved by selectively oligomerising light FCC alkenes (olefins) for recycle cracking in the FCC unit. By adjusting catalyst formulations and operating conditions, the FCC process can be adapted to operate in different modes, including the maximisation of propylene.

Prime-G+, GT-BTX PluS, GT-BTX PluS Extract, FlexEne, and Polynaphtha are marks of Axens.

Apr-2024
Pierres-Yves Le-Goff, AXENS, Pierre-Yves.LE-GOFF@axens.net

AI and data analysis techniques can analyse complex refinery processes to identify optimisation opportunities. They can predict optimal operating conditions and adjust parameters in real-time to maximise yields and energy efficiency while meeting emissions standards. Here we give several illustrations:
• In addition to gasoline and aromatic production from a reformer unit, the other major product is hydrogen. This hydrogen has a low carbon index compared to the one coming from steam methane reforming (SMR) by a factor of around eight. Therefore, any extra hydrogen production is critical. However, to give advice to increase hydrogen production at a first stage, an accurate estimation of the current hydrogen yield is important. This task is not easy as gas flowmeters are not so accurate most of the time. In that context, Axens has developed special tools to accurately follow hydrogen production using in-house data clustering, mass balance closure methodology, and principal component analysis. Based on hybrid models, first principles and machine learning, new set points can be defined to maximise hydrogen and aromatics production.
• Another example is the optimisation of the recycle gas flow rate. Typically, recycle compressors use steam. Consequently, any reduction of the flow has a direct impact on the unit carbon intensity. Again, based on hybrid models, the recycle gas can be reduced to meet either regenerator coke burning capacity or the requested cycle length for a semi-regenerative unit.
• Multivariable advanced control embedded to advanced process control uses mathematical models to predict the future behaviour of the process and optimise control actions accordingly. This helps in maintaining optimal conditions for catalysts and reactors to achieve higher yields while minimising emissions.
• Creating digital twins of refining processes allows for simulation and testing of different scenarios without affecting the actual operation. Applied to the aromatics complex, data densification techniques coupled with real-time monitoring enable an aromatic production increase by maximising benzene precursors in the continuous catalyst reforming (CCR) unit inlet. Operational improvements such as octane optimisation in a catalytic reforming process as a function of pool requirement or hydrogen-to-hydrocarbon molar ratio adjustment minimising energy consumption will favour CO₂ emissions reduction.

Apr-2024