Catalytic upgrading of biomass pyrolysis vapors and model compounds using niobia supported Pd catalyst
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Teles, Camila A.↗
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Method for Hot Real-Time Sampling of Pyrolysis Vapors
Biomass Pyrolysis has been an increasing topic of research, in particular as a replacement for crude oil. This process utilizes moderate temperatures to thermally deconstruct the biomass which is then condensed into a mixture of liquid oxygenates to be used as fuel precursors. Pyrolysis oils contain more than 400 compounds, up to 60 percent of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during the condensation and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors, many challenges must be overcome. Sampling must occur within a narrow range of temperatures to reduce product composition changes from overheating or partial condensation or plugging of lines from condensed products. Residence times must be kept at a minimum to reduce further reaction chemistries. Pyrolysis vapors also form aerosols that are carried far downstream and can pass through filters resulting in build-up in downstream locations. The co-produced bio-char and ash from the pyrolysis process can lead to plugging of the sample lines, and must be filtered out at temperature, even with the use of cyclonic separators. A practical approach for considerations and sampling system design, as well as lessons learned are integrated into the hot analytical sampling system of the National Renewable Energy Laboratory's (NREL) Thermochemical Process Development Unit (TCPDU) to provide industrially relevant demonstrations of thermochemical transformations of biomass feedstocks at the pilot scale.
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Catalytic Hot-Gas Filtration with a Supported Heteropolyacid Catalyst for Preconditioning Biomass Pyrolysis Vapors
During ex situ catalytic fast pyrolysis (CFP) of biomass, the separation of reactive char and alkali/alkaline particulates from biomass pyrolysis vapors by hot-gas filtration (HGF) leads to improved vapor stability and quality. HGF in tandem with chemical tailoring (e.g., partial deoxygenation) of the clean pyrolysis vapors, denoted as catalytic hot-gas filtration (CHGF), has the potential to further improve vapor composition by removing reactive oxygen moieties and protect downstream upgrading catalysts from fouling. Downstream upgrading refers to both vapor phase upgrading (e.g., ex situ CFP) and condensed phase upgrading (e.g., hydrotreating). Consequently, CHGF (as a single unit operation) was evaluated for preconditioning pyrolysis vapors for downstream upgrading processes. In order to understand the effective operating conditions that successfully filter and partially deoxygenate pyrolysis vapors, a titania-supported molybdenum heteropolyacid (Mo-HPA/TiO 2 ) catalyst was studied for use in CHGF. Here, pine pyrolysis vapors were generated in a small pilot-scale pyrolyzer and transferred to a CHGF unit via a continuous-flow slipstream. In the CHGF unit, the pyrolysis vapors were filtered and upgraded over a packed Mo-HPA/TiO 2 catalyst bed. Real-time monitoring and identification of the products formed were achieved by molecular beam mass spectrometry. The results showed that under a hydrogen-rich environment, the pine vapors were partially deoxygenated and alkylated over the Mo-HPA/TiO 2 catalyst. Reactivity studies revealed that an increase in hydrogen concentration and a reduction in weight-hourly space velocity enhanced deoxygenation and alkylation. Time-on-stream (TOS) studies showed stable product formation up to 1 h with little change in catalyst activity. Additionally, the liquid product was collected using a custom fractional condensation unit (built in-house) and analyzed by gas chromatography mass spectrometry to confirm that the product was partially deoxygenated and alkylated. The combination of CHGF and fractional condensation allowed for chemical and physical removal of both foulant and value-added compounds (e.g., phenols, alkylphenols, methoxyphenols, cyclopentenones) for additional enhancement of downstream upgrading processes. The pre- and postreaction catalysts were characterized using temperature-programmed desorption, N 2 physisorption, and elemental analysis with results indicating some catalyst coking. A hydrogen-based catalyst regeneration procedure restored the reacted catalyst activity to that of fresh Mo-HPA/TiO 2 .
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Vapor-Phase Stabilization of Biomass Pyrolysis Vapors Using Mixed-Metal Oxide Catalysts
Mixed-metal oxides possess a wide range of tunability and show promise for catalytic stabilization of biomass pyrolysis products. For materials derived from layered double hydroxides, understanding the effect of divalent cation species and divalent/trivalent cation stoichiometric ratio on catalytic behavior is critical to their successful implementation. In this study, four mixed-metal oxide catalysts consisting of Al, Zn, and Mg in different stoichiometric ratios were synthesized and tested for ex-situ catalytic fast pyrolysis (CFP) using pine wood as feedstock. The catalytic activity and deactivation behavior of these catalysts were monitored in real-time using a lab-scale pyrolysis reactor and fixed catalyst bed coupled with a molecular beam mass spectrometer (MBMS), and data were analyzed by multivariate statistical approaches. In the comparison between Mg-Al and Zn-Al catalyst materials, we demonstrated that the Mg-Al materials possessed greater quantities of basic sites, which we attributed to their higher surface areas, and they produced upgraded pyrolysis vapors which contained less acids and more deoxygenated aromatic hydrocarbons such as toluene and xylene. However, detrimental impacts on carbon yields were realized via decarbonylation and decarboxylation reactions and coke formation. Given that the primary goals of catalytic upgrading of bio-oil are deoxygenation, reduction of acidity, and high carbon yield, these results highlight both promising catalytic effects of mixed-metal oxide materials and opportunities for improvement.
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The Development of Catalysts for Upgrading of Pyrolysis Vapor for Refinery Feedstocks and Intermediates (CRADA Final Report)
Catalytic fast pyrolysis (CFP) is a versatile technology platform to convert biomass into fungible hydrocarbon transportation fuels and chemical co-products. Key technical barriers to reaching this goal include increasing the product yields and achieving the desired fuel properties for gasoline, diesel, and jet range fuels or blendstocks that would be suitable for introduction into existing refinery unit operations. Overcoming these barriers will require durable catalysts that are effective at upgrading and stabilizing biomass pyrolysis vapors. Towards these goals, this CRADA leveraged NREL experience as a leader in biomass pyrolysis research and Johnson Matthey's (JM) experience as a leader in the production of advanced catalytic materials. The scope spanned CFP catalyst development, characterization, multi-scale reaction testing, and computational modeling. CRADA benefits to DOE, Participant, and U.S. Taxpayer: Assists laboratory in achieving programmatic scope, Uses the laboratory’s core competencies. The purpose of this CRADA was to develop and deploy catalysts for biomass CFP to help achieve cost-competitive biofuels and bio-based products. This was accomplished through a close collaboration between biomass conversion researchers at NREL and catalyst development researchers at JM. Summary of Research Results: Focus Area 1. Foundational research on catalytic conversion and deactivation: Key interactions between pyrolysis vapors and heterogeneous catalysts were probed through catalyst characterization, model compound reaction testing, and atomistic-scale computational modeling. Catalyst development focused on multifunctional materials, which include zeolites, oxides, carbides, and nitrides. Computational modeling identified reaction mechanisms and elucidated surface chemistry to test hypotheses regarding mechanisms of deoxygenation, coupling, cracking, dehydration, coke formation, hydrogen transfer, and aromatic ring reactions. This information was used to design multifunctional catalysts to increase product yields, control product selectivity, and reduce deactivation during CFP and downstream processing steps. The results served to increase fundamental understanding of key catalyst attributes and durability features for the upgrading of biomass pyrolysis vapors. Model compound experiments confirmed the importance of metal-acid bifunctionality for the deoxygenation of lignin-derived phenolic species under hydrodeoxygenation conditions. This insight led to the development of catalysts such as Pt/TiO2 and Mo2C, which were confirmed as high-performing materials during subsequent bench-scale experiments using biomass-derived pyrolysis vapors. This focus area also led to the identification of important catalyst deactivation mechanisms associated with the deposition of inorganic contaminants such as potassium. The molecular-level insight from model compound experiments and computational modeling, shown in Figure 1, informed the development of regeneration procedures that have been shown to be effective for restoration of > 90% of initial catalyst activity. This understanding has subsequently been translated to other catalyst systems, including zeolite materials that can be operated without requirements for co-fed hydrogen.
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Fractional condensation of pyrolysis vapors produced from Nordic feedstocks in cyclone pyrolysis
Pyrolysis oil is a complex mixture of different chemical compounds with a wide range of molecular weights and boiling points. Due to its complexity, an efficient fractionation of the oil may be a more promising approach of producing liquid fuels and chemicals than treating the whole oil. In this work a sampling system based on fractional condensation was attached to a cyclone pyrolysis pilot plant to enable separation of the produced pyrolysis vapors into five oil fractions. The sampling system was composed of cyclonic condensers and coalescing filters arranged in series. Our objective was to characterize the oil fractions produced from three different Nordic feedstocks and suggest possible applications. The oil fractions were thoroughly characterized using several analytical techniques including water content; elemental composition; heating value, and chemical compound group analysis using solvent fractionation, quantitative 13 C NMR and 1 H NMR and GC x GC - TOFMS. The results show that the oil fractions significantly differ from each other both in chemical and physical properties. The first fractions and the fraction composed of aerosols were highly viscous and contained larger energy-rich compounds of mainly lignin-derived material. The middle fraction contained medium-size compounds with relatively high concentration of water, sugars, alcohols, hydrocarbonyls and acids and finally the last fraction contained smaller molecules such as water, aldehydes, ketones and acids. But, the properties of the respective fractions seem independent on the studied feedstock types, i.e. the respective fractions produced from different feedstock are rather similar. Furthermore, this promotes the possibility to vary the feedstock depending on availability while retaining the oil properties. Possible applications of the five fractions vary from oil for combustion and extraction of the pyrolytic lignin in the early fractions to extraction of sugars from the early and middle fractions, and extraction of acids and aldehydes in the later fractions.
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High-resolution mass spectrometric analysis of biomass pyrolysis vapors
Vapors generated from the pyrolysis of lignocellulosic biomass are made up of a complex mixture of oxygenated compounds. Direct analysis of these vapors provides insight into the mechanisms of depolymerization of cellulose, hemicellulose, and lignin as well as insight into reactions that may occur during condensation of pyrolysis vapors into bio-oil. Studies utilizing pyrolysis molecular beam mass spectrometry have provided valuable information regarding the chemical composition of pyrolysis vapors. Mass spectrometers generally employed with these instruments have low mass resolution of approximately a mass unit. The presence of chemical species with identical unit mass but differing elemental formulas cannot be resolved with these instruments and are therefore detected as a single ion. In this study we analyzed the pyrolysis vapors of several biomass sources using a high-resolution double focusing mass spectrometer. High-resolution analysis of pyrolysis vapors allowed for speciation of several compounds that would be detected as a single ion with unit mass resolution. Lastly, these data not only provide greater detail into the composition of pyrolysis vapors but also highlight differences between vapors generated from multiple biomass feedstocks.
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Deactivation of Multilayered MFI Nanosheet Zeolite during Upgrading of Biomass Pyrolysis Vapors
Here, the catalytic fast pyrolysis (CFP) of biomass is a promising technology for producing renewable transportation fuels and chemicals. MFI-type catalysts have shown promise for CFP because they produce gasoline range hydrocarbons from oxygenated pyrolysis compounds; however, rapid catalyst deactivation due to coking is one of the major technical barriers inhibiting the commercialization of this technology. Coke deposited on the surface of the catalysts blocks access to active sites in the micropores leading to rapid catalyst deactivation. Our strategy is to minimize rapid catalyst deactivation by adding mesoporosity through forming MFI nanosheet materials. The synthesized MFI nanosheet catalysts were fully characterized and evaluated for cellulose pyrolysis vapor upgrading to produce olefins and aromatic hydrocarbons. The data obtained from pyrolysis-GCMS (py-GCMS), showed that fresh MFI nanosheets produced similar aromatic hydrocarbon and olefin yields compared to conventional HZSM-5. However, MFI nanosheets demonstrated a longer lifetime than HZSM-5 even though coke contents were also higher than for HZSM-5 because the mesopores enabled better accessibility to active acid sites. This conclusion was supported by results from post-reaction analysis of various spent catalysts collected at different points during the deactivation experiments.
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Pyrolysis Vapor and Bio-Oil Preconditioning via Ex Situ Hydrodeoxygenation and Alkylation Using a Heteropolyacid Catalyst
Ex situ catalytic preconditioning of biomass pyrolysis vapors (partial deoxygenation) has the potential for both reducing the oxygen content and beneficially influencing the oxygen speciation of condense bio-oils for enhancement of downstream condensed phase upgrading processes. Here, condensed phase upgrading processes may refer to both coprocessing and hydroprocessing with vacuum gas-oil (VGO). Reduction of oxygen content to produce bio-oils with greater hydrophobicity can enhance VGO-solubility while tailoring of oxygen speciation by removal of reactive carbonyls (e.g., acetic acid) can lessen catalytic deactivation via coking reactions. 1,2 Furthermore, enhanced VGO-solubility and reduced coking leads to greater biogenic carbon incorporation in end-products from condensed phase upgrading processes. By leveraging the hydrodeoxygenation and alkylation activity of a titania-supported molybdenum-heteropolyacid (Mo-HPA/TiO2) catalyst, pyrolysis vapors and resulting condensed bio-oils were effectively preconditioned for downstream upgrading. 3 Data regarding the use of Mo-HPA/TiO2 for pyrolysis vapor preconditioning will be presented on, including method of employment, catalyst characterization, and impacts on bio-oil in relation to downstream condensed phase upgrading processes. Our approach is to: Compare Mo-HPA/TiO2 product distribution to HZSM-5; Investigate Mo-HPA/TiO2 regeneration and characterize changes in acid site character; Assess product differences in terms of enhanced VGO-solubility.
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Effect of ZSM-5 acidity on aromatic product selectivity during upgrading of pine pyrolysis vapors
The impact of catalyst acidity on the selectivity of upgraded biomass pyrolysis products was studied by passing pine pyrolysis vapors over five ZSM-5 catalysts of varying acidity at 500 degrees C. The SiO 2 -to-Al 2 O 3 ratio (SAR) of the ZSM-5 zeolite was varied from 23 to 280 to control the acidity of the catalyst and the composition of upgraded products. The upgraded product stream was analyzed by GCMS. Additionally, catalysts were characterized using temperature programmed desorption, diffuse-reflectance FTIR spectroscopy, N 2 physisorption, and X-ray diffraction. The results showed that the biomass pyrolysis vapors were highly deoxygenated to form a slate of aromatic hydrocarbons over all of the tested ZSM-5 catalysts. As the overall acidity of the ZSM-5 increased the selectivity toward alkylated (substituted) aromatics (e.g., xylene, dimethyl-naphthalene, and methyl-anthracene) decreased while the selectivity toward unsubstituted aromatics (e.g., benzene, naphthalene, and anthracene) increased. Additionally, the selectivity toward polycyclic aromatic compounds (2-ring and 3-ring) increased as catalyst acidity increased, corresponding to a decrease in acid site spacing. The increased selectivity toward less substituted polycyclic aromatic compounds with increasing acidity is related to the relative rates of cyclization and alkylation reactions within the zeolite structure. As the acid site concentration increases and sites become closer to each other, the formation of additional cyclization products occurs at a greater rate than alkylated products. The ability to adjust product selectivity within 1-, 2-, and 3-ring aromatic families, as well as the degree of substitution, by varying ZSM-5 acidity could have significant benefits in terms creating a slate of upgraded biomass pyrolysis products to meet specific target market demands.
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Multiscale Evaluation of Catalytic Upgrading of Biomass Pyrolysis Vapors on Ni- and Ga-Modified ZSM-5
Metal-impregnated (Ni or Ga) ZSM-5 catalysts were studied for biomass pyrolysis vapor upgrading to produce hydrocarbons using three reactors constituting a 100 000x change in the amount of catalyst used in experiments. Catalysts were screened for pyrolysis vapor phase upgrading activity in two small-scale reactors: (i) a Pyroprobe with a 10 mg catalyst in a fixed bed and (ii) a fixed-bed reactor with 500 mg of catalyst. The best performing catalysts were then validated with a larger scale fluidized-bed reactor (using ~1 kg of catalyst) that produced measurable quantities of bio-oil for analysis and evaluation of mass balances. Despite some inherent differences across the reactor systems (such as residence time, reactor type, analytical techniques, mode of catalyst and biomass feed) there was good agreement of reaction results for production of aromatic hydrocarbons, light gases, and coke deposition. Relative to ZSM-5, Ni or Ga addition to ZSM-5 increased production of fully deoxygenated aromatic hydrocarbons and light gases. In the fluidized bed reactor, Ga/ZSM-5 slightly enhanced carbon efficiency to condensed oil, which includes oxygenates in addition to aromatic hydrocarbons, and reduced oil oxygen content compared to ZSM-5. Ni/ZSM-5, while giving the highest yield of fully deoxygenated aromatic hydrocarbons, gave lower overall carbon efficiency to oil but with the lowest oxygen content. Reaction product analysis coupled with fresh and spent catalyst characterization indicated that the improved performance of Ni/ZSM-5 is related to decreasing deactivation by coking, which keeps the active acid sites accessible for the deoxygenation and aromatization reactions that produce fully deoxygenated aromatic hydrocarbons. The addition of Ga enhances the dehydrogenation activity of the catalyst, which leads to enhanced olefin formation and higher fully deoxygenated aromatic hydrocarbon yields compared to unmodified ZSM-5. Catalyst characterization by ammonia temperature programmed desorption, surface area measurements, and postreaction temperature-programmed oxidation (TPO) also showed that the metal-modified zeolites retained a greater percentage of their initial acidity and surface area, which was consistent between the reactor scales. These results demonstrate that the trends observed with smaller (milligram to gram) catalyst reactors are applicable to larger, more industrially relevant (kg) scales to help guide catalyst research toward application.
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Method for Hot Real-Time Analysis of Pyrolysis Vapors at Pilot Scale
Pyrolysis oils contain more than 400 compounds, up to 60% of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during quenching and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors at the pilot scale, many challenges must be overcome.
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Role of Pt during hydrodeoxygenation of biomass pyrolysis vapors over Pt/HBEA
1.3 wt% Pt/HBEA and HBEA were studied as catalysts for the hydrodeoxygenation of pine pyrolysis vapors at 500 °C. Both catalysts showed high initial conversion of oxygenated pyrolysis products into aromatic hydrocarbons, while Pt/HBEA showed higher stability in terms of hydrocarbon productivity and deferred breakthrough of oxygenated compounds. Among 1-, 2- and 3-ring aromatic hydrocarbons, Pt/HBEA had a significantly higher selectivity than HBEA towards unalkylated aromatics (e.g., benzene) as compared to the corresponding alkylated aromatics (e.g., toluene and xylene). Additionally, Pt addition to HBEA decreased coke deposition and improved resistance to pore and acid site blockage as determined by TPO, N 2 physisorption, and NH 3 TPD. The ability of Pt to promote cleavage and hydrogenation of methoxy and methyl groups was observed by increased methane production over Pt/HBEA relative to HBEA. A progressive decrease in the methane production over Pt/HBEA correlated with deactivation in terms of reduced benzene formation, breakthrough of oxygenated products, and increased formation of polynuclear aromatics and their degree of substitution, which indicate coke formation. In conclusion, the increased methane yield and suppressed coke formation with the addition of Pt is attributed to hydrogen spillover, through which hydrogen activated on Pt can subsequently migrate to the HBEA support to reverse the coke-forming hydrogen abstraction reaction.
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BETO 2021 Peer Review - Catalytic Upgrading of Pyrolysis Vapors 2.3.1.314
Catalytic fast pyrolysis (CFP) is a versatile pathway for the direct liquefaction of biomass and waste carbon sources to generate a stabilized bio-oil intermediate that can be further processed into renewable fuels, chemicals, and materials. The objective of this project is advance the CFP state-of-technology through integrated catalyst and process development, expand market responsiveness by creating routes to novel co-products, and provide experimental data to inform process modelling and scale-up activities. Research advancements over the past two years include reducing analytical uncertainty by achieving 100 ± 1% carbon balances during reaction testing with woody biomass, improving process efficiency by achieving a 4x increase in catalyst cycle length, demonstrating compatibility with waste feedstocks, and confirming process durability for 100+ reaction cycles. Additionally, this project supported a comprehensive pathway review to evaluate scale-up needs. This review resulted in the early identification of technical risks and informed proactive planning for the BETO 2022 Verification. Other impacts from this project include generation of broadly enabling scientific knowledge (14 publications/18 presentations since 2019), engagement with industry partners (e.g., Johnson Matthey and ExxonMobil), and identification of a promising pathway to market that addresses emerging demands for biogenic refinery feedstocks.
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The Development of Catalysts for Upgrading of Pyrolysis Vapor for Refinery Feedstocks and Intermediates: Cooperative Research and Development, CRADA Number CRD-12-00497 (Final Report)
Fast pyrolysis of biomass with vapor phase upgrading (VPU) can produce refinery feedstocks or intermediates that can meet the Department of Energy’s goal of cost-competitive hydrocarbon fuels by 2017. A key technical barrier for this technology is the lack of selective, cost effective catalysts that can produce high yields of fuel-appropriate hydrocarbons from the pyrolysis vapors. In overcoming this barrier, it will be important to engage leading catalyst development companies to devote their resources and expertise to the development of these materials. Thus, we propose a Cooperative Research and Development Agreement (CRADA) between the National Renewable Energy Laboratory (NREL), a world leader in biomass pyrolysis research and Johnson Matthey (JM), a world leader in the production of advanced catalyst materials to develop and test novel catalysts for efficient VPU. Through its Intercat Inc. subsidiary in Savannah, Ga., Johnson Matthey is internationally recognized as a leader in zeolite-based vapor phase upgrading in refinery duties and an emerging developer of biomass conversion technologies. The research and development efforts described in the proposed work will build upon existing collaborations between NREL and JM and play to the strengths of both institutions. NREL will analyze the composition of pyrolysis vapors as an input to catalyst design, screen and test catalysts, characterize the resulting oil and conduct techno-economic analysis. Catalyst samples will be produced and funded by JM. JM will design and synthesize catalysts, characterize fresh and used catalysts and develop catalyst supports needed to achieve commercially meaningful lifetimes. The project will span catalyst development and testing from the fundamental stage using quantum mechanical modeling and chemical reaction analysis to catalyst screening to integrated pilot studies.
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CFD Simulation of Biomass Pyrolysis Vapor Upgrading over a Pt/TiO 2 Catalyst in Fixed and Moving Beds
This report presents a comprehensive computational fluid dynamics (CFD) study of the biomass pyrolysis vapor phase upgrading and the catalyst regeneration in different reactors under various operational conditions. This study used the open-source software Multiphase Flow with Interphase eXchanges (MFiX), developed at National Energy Technology Laboratory (NETL) for simulating hydrodynamics, heat transfer, and chemical reactions in multiphase systems. This simulation solved the conservation of mass, momentum, energy, species for gas and solid phases with chemical reactions.
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Validation and application of a multiphase CFD model for hydrodynamics, temperature field and RTD simulation in a pilot-scale biomass pyrolysis vapor phase upgrading reactor
Accurate prediction of transport phenomena is critical for VPU reactor design, optimization, and scale-up. The current study focused on the validation and application of a multiphase CFD model within an open-source code MFiX for hydrodynamics, temperature field, and residence time distribution (RTD) simulation in a non-reacting circulating fluidized bed riser for biomass pyrolysis vapor phase upgrading (VPU). First, an Eulerian-Eulerian approach three-dimensional CFD model was employed to simulate the pilot-scale VPU riser on the supercomputer Joule. Excellent quantitative agreement between experimental and simulated results was achieved for pressure drops and temperature field in a range of operating conditions. Then the validated multiphase CFD model was applied to predict gas and solid residence time distributions (RTDs) since prediction and analysis of RTD is an important tool to study the complex multiphase flow behavior and mixing inside chemical reactors. The predictions show that solid mean residence time is 3.5 times the gas residence time; the solid RTD is more sensitive to the process gas flow rate than the solids circulation rate.
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Predicting Catalytic Pyrolysis Aromatic Selectivity from Pyrolysis Vapor Composition Using Mass Spectra Coupled with Statistical Analysis
The behavior of fast pyrolysis (FP) and catalytic FP (CFP) of 20 renewable feedstocks was studied in a microscale reactor with molecular beam mass spectral analysis of products generated. A partial least-squares (PLS) model was constructed based on the FP vapor spectra that predicts the aromatic selectivity when upgrading over a ZSM-5 catalyst. Additionally, principal component analysis of both FP and CFP spectra was performed for comprehensive spectral analysis. This work highlighted the value of vapor-phase mass spectral screening to predict the subsequent feedstock performance and demonstrated that the quantity of coke deposited on the catalyst is not a reliable measure of catalyst deactivation when the feedstock type is varied.
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