Microactivity Test Research Articles

Influence of Metals on Metal Modified ZSM-5 Catalysts to Cracking Selectively Fraction C9+ of Vietnamese Naphtha

Background: In the search of new catalysts for conversion of heavy naphtha fraction (C9+) into high octane number gasoline, metal modified ZSM-5 catalysts were investigated. The result revealed that modification ZSM-5 with metals (Ni, Fe, Zn) increased the C9+ fraction conversion and reduced the gas formation. In addition, hydrogen yield has increased the presence of Ni in the catalysts, whereas the number was reduced with other metals modification. Moreover, metal modified catalysts effectively prevented coke formation. Characterization studies (BET, XRD, TPR, TPD) results elucidated the effects of metals on catalytic performance. All the prepared catalysts possessed similar specific surface areas, thus the tuning of metallic sites was decisive for good catalyst performance. The combination of metallic sites (e.g. Ni) and acidic sites, supports all necessary reactions (e.g. cracking, aromatization, cyclization, alkylation, dehydrogenation, H-transfer) and thus helps to increase both heavy fraction conversion and reduces the coke formation. The finding might provide potential strategies for naphtha cracking. Methods: Modified ZSM-5 catalysts with different metals were synthesized by hydrothermal crystallization method using TPABr (Sigma Aldrich) as a template. The prepared catalysts were evaluated for catalytic cracking of C9+ fraction of Vietnamese naphtha using a fully automated standardized Single Receiver – Short Contact Time - Microactivity Test. Then, catalysts characterization and catalytic performance were evaluated in order to verify the hypothesis and find out the useful strategies. Results: In the present study, we reported an effective catalyst for cracking of heavy fraction of Vietnamese naphtha (C9+ fraction). The combination of metallic sites and acidic sites not only increase the conversion of heavy fraction into lighter fraction but also increase olefins and aromatics fraction in the gasoline. In addition, the modification with metals, especially with Ni would reduce the acidic sites of the modified catalyst and thus strongly prevent coke formation. Conclusion: These findings might provide some valuable strategies for the development of effective catalysts for naphtha cracking and further uses reforming reaction in the simultaneous cracking and reforming. Such tests are now in progress. Keywords: Selectively catalytic cracking, C9+ fraction, metal modified ZSM-5 catalysts, Vietnamese naphtha, catalyst metal.

Catalytic cracking of triglycerides over micro/mesoporous zeolitic composites prepared from ZSM-5 precursors with varying aluminum contents

A series of micro/mesoporous nano-ZSM-5/SBA-15 analog composites (ZSC) was prepared from ZSM-5 precursors with variable aluminum contents (Si/Al ratio = 10–50) and their catalytic performance was evaluated in the cracking of waste vegetable oil under the fluid catalytic cracking conditions using a Single-Receiver Short-Contact-Time Microactivity Test unit (SR-SCT-MAT, Grace Davison). It was found that the preparation of the ZSC catalyst by properly tuning the initial aluminum content enables to improve its catalytic performance in terms of selectivity toward light olefins and quality of gasoline. Compared to single materials, i.e. microporous H-ZSM-5 and mesoporous Al-SBA-15, the ZSC catalyst shows the enhanced concentration of C3 and C4 olefins in the gaseous hydrocarbon fraction (ca. 85%) while lowering that of aromatic hydrocarbons in the gasoline fraction (ca. 40%). Furthermore, the reduced aromatic hydrocarbons are offset by the more environment-friendly components for boosting the octane rating of gasoline, i.e. iso-paraffins and iso-olefins. The superior catalytic performance of the ZSC catalyst can be attributed to the bimodal pore system coupled to the medium acid amount, which effectively suppresses hydrogen transfer reactions of primary light olefins while facilitating the cracking and isomerization transformations of hydrocarbon intermediates, leading to the improved formation of C3 and C4 olefins and branched gasoline hydrocarbons.

Catalytic Cracking of Light Crude Oil to Light Olefins and Naphtha over E-Cat and MFI: Microactivity Test versus Advanced Cracking Evaluation and the Effect of High Reaction Temperature

The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared using two laboratory testing techniques, a fixed-bed microactivity test (MAT) unit and a fixed fluidized-bed advanced cracking evaluation (ACE) unit. Both units were operated using equilibrated FCC catalyst (E-Cat), MFI zeolite (ZSM-5), and E-Cat/MFI (equal mixture with MFI) at two temperatures (550 and 600 °C) and a constant catalyst-to-oil ratio of 4.0. Despite the different hydrodynamics in MAT and ACE reactors, both units gave similar catalyst ranking based on the conversion of 221+ °C feed fraction at 550 and 600 °C in the order of E-Cat > E-Cat/MFI > MFI, which is attributed to diffusion limitation of MFI catalyst. While both testing techniques showed variation in product yield structure (dry gas, LPG, naphtha, and unconverted 221+ °C) over the three catalysts, the ACE unit gave significantly higher coke yield compared with MAT. The highest yield of light olefins was obtained over E-Cat/MFI (29 wt %) at 600 ...

Catalytic removal of soot particles over MnCo2O4 catalysts prepared by the auto-combustion method

Soot removal for exhaust gas from diesel engine has been addressed due to the more stringent legislation and environmental concerns. MnCo2O4 catalysts were systematically prepared using glucose as a fuel via the auto-combustion method and applied for soot removal. The as-prepared samples were characterized by X-ray diffraction (XRD), O2-temperature-programmed oxidation (TPO) reaction and H2-temperature-programmed reduction reaction (H2-TPR). The catalytic activities for soot combustion were evaluated by micro activity test (MAT) with a tight contact mode between soot and catalysts. Compared with catalysts prepared by the solid state method without glucose, auto-combustion method in the presence of glucose can decrease the synthetic temperature, avoiding high temperature treatment and sintering. The catalysts prepared with glucose could catalyze soot oxidation effectively and the derived values of T10, T50, and T90 were 326, 408, and 468 °C in a tight contact mode, respectively, showing a significant drop of T10, T50, and T90 by 156, 177, and 178 °C for non-catalytic reaction.

Physical mixture of MCM-41/ZSM-5 as an active catalyst component for maximization of propylene in Catalytic cracking of VGO

ABSTRACTThe performance of a novel catalyst additive containing highly porous MCM-41 and ZSM-5 zeolite was investigated using a commercial equilibrium FCC catalyst in catalytic cracking of vacuum gas oil. The catalytic tests were assessed in a fixed-bed microactivity test unit at reaction temperatures 500–620 °C. The highest propylene yield of 23.8 wt% was achieved at 600 °C. The propylene yield increased from 14.49 wt% to 23.8 wt% when the temperature rose from 500 to 600 °C; however the gasoline yield fell from 22.47wt% to 16.49 wt% by increasing the temperature from 580 °C to 620 °C, respectively.

Catalytic Cracking of Light Crude Oil: Effect of Feed Mixing with Liquid Hydrocarbon Fractions

The direct catalytic cracking of Arab Extra Light (AXL) crude oil was conducted in a microactivity test (MAT) unit at 550 °C, where product recycling was simulated by mixing feed and liquid products in varying proportions. The effect of AXL mixing with total liquid product (LP) or a mixture of light cycle oil (LCO) and heavy cycle oil (HCO) was investigated at various ratios to determine the dependence of light olefins yield on feed composition. It was observed that mixing the least amount of LP with AXL yielded ∼20.3 wt % light olefins and 39.6 wt % naphtha. The cracking of AXL and LCO+HCO yielded similar results as the case of cracking LP. A configuration of 100% recycle of liquid product without blending with AXL feed showed an increase in the yield of light olefins from 20 wt % to 29 wt % associated with a decrease in naphtha yield from 40 wt % to 27 wt %. A second configuration of 100% recycle of LCO+HCO without blending with AXL feed showed that the yield of light olefins increased from 20 wt % to 26 wt % associated with an increase in naphtha yield from 40 wt % to 50 wt %. The study has shown that the recycling of low-value heavy fraction (LCO+HCO) is a cost-effective means to supplement the AXL feed without loss in the yield of desired light olefins and naphtha.

Effect of cerium ions initial distribution on the crystalline structure and catalytic performance of CeY zeolite

CeY samples with different cerium (Ce) ions initial distribution were prepared by diverse preparation processes. The correlative influence of Ce ions distribution on the intracrystalline structure and catalytic mechanism of Y-type zeolite was studied by X-ray diffraction (XRD), Rietveld refinement, X-ray fluorescence spectrometry (XRF), energy-dispersive X-ray spectroscopy (EDS), infrared (IR) spectra, NH3 temperature-programmed desorption (NH3-TPD), N2 physical adsorption-desorption and micro-activity test (MAT). The results indicated that Ce ions were concentrated on the surface (supercage) of CeY zeolite would reduce the number of acid sites and the ratio of Brönsted acid and Lewis acid (B/L). Once Ce ions concentrated in the sodalite cage, it would participate in the coordination with framework oxygen atoms under the condition of steric hindrance. Meanwhile, Ce ions would preferentially promote the B/L value of weak acid by retaining more intracrystalline framework Al atoms in sodalite cage, which was beneficial to the conversion of heavy oil in FCC process. The optimal initial-distribution of Ce ions could not only save the consumption of rare earth resources but also give the best catalytic performance of CeY zeolite catalysts, and these advantages and attributes enabled it to have the potential to be applied in industrial applications.

Investigation on the cation location, structure and performances of rare earth-exchanged Y zeolite

A series of Y zeolites exchanged with different amount of cerium and lanthanum cations were investigated. Comprehensive routine analysis tools including X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), X-ray diffraction (XRD) and Py-Fourier transform infrared spectroscopy (Py-FTIR) were used to identify the cation location, and the result was verified via XRD Rietveld study. The results revealed that almost all the RE cations in RE-4, most cations in RE-8 to RE-14 and part of cations in RE-16 were located in the sodalite cage. The AlIV/(AlV+AlVI) values revealed by 27Al MAS NMR spectra, the silicon aluminum ratio of the framework (SARF) values deduced from 29Si MAS NMR spectra and XRD, and hydroxyl amount were reasonably in accordance with the location and content of rare earth cations. The hydrothermal stability derived from in situ XRD investigation and catalyst activity provided by micro-activity test manifested that samples RE-8 to RE-14 exhibited better performances than RE-4 and RE-16, among which RE-12 had the best properties. The phenomena were interpreted by the cation location and structural properties.

Catalytic cracking of vacuum gasoil over -SVR, ITH, and MFI zeolites as FCC catalyst additives

The cracking behaviour of three medium-pore zeolites -SVR, ITH, and MFI, with varying Si/Al molar ratio, was evaluated using an equilibrium FCC catalyst (E-Cat) and a hydrotreated vacuum gasoil (VGO) in a microactivity test unit (MAT). The increase in the yield of light olefins (21–29wt% over E-Cat/additive vs. 16wt% over E-Cat) was accompanied by a drop in the yield of gasoline (26–39wt% over E-Cat/additive vs. 43wt% over E-Cat) due to the cracking of reactive species in gasoline fraction (mainly olefins and isoparaffins). With increasing Si/Al ratio in zeolites MFI-280 and –SVR-120, propylene yield passed through maxima reaching 13.5wt% and 12.8wt%, respectively, compared with 7.0wt% over E-Cat. Maximum propylene yield occurred partially due to gasoline over-cracking to light olefins (inverse relation with Si/Al ratio). The effect of MFI crystal size showed that large size crystals enhanced the yield of light olefins as compared to small size crystals due to secondary cracking of gasoline molecules. Results of kinetic study based on 4-lump model showed proportional relation between MFI Si/Al ratio and activation energy for the conversion of gasoline to gases. Activation energy increased from 14.2kcal/mol to 16.3kcal/mol as Si/Al ratio increased from 30 to 2000.

Catalytic cracking of crude oil to light olefins and naphtha: Experimental and kinetic modeling

The direct catalytic cracking of three light crude oils have been evaluated over an equilibrated FCC catalyst (E-Cat) blended with MFI zeolite in a microactivity test unit at 550°C and catalyst/oil ratio between 1 to 4. At 60% conversion, the Super Light (ASL) crude oil yielded about 10wt.% C2–C4 olefins and 60wt.% naphtha over E-Cat, Extra Light (AXL) crude oil yielded 13wt.% light olefins and 52wt.% naphtha, while for Arab Light (AL) crude oil, light olefins and naphtha produced were 12 and 51wt.%, respectively. The addition of MFI with varying Si/Al molar ratio (Z30, Z280 and Z1500) to E-Cat increased the yield of light olefins with a maximum at 21.3wt.% for AXL over E-Cat/Z280. PIONA analysis of co-produced naphtha showed an increase in aromatics content over all additives with a maximum obtained from the cracking of AL over Z30 (91wt.%). Steam treatment of Z280 led to a slight change in the yield of light olefins and reduction of naphtha aromatics for the three types of crude oils. A four-lump kinetic model accurately predicted experimental yields of AL cracking over E-Cat and E-Cat/Z280 between 500°C and 550°C. From the kinetic model, the apparent activation energy for the conversion of naphtha to gases decreased from 21.2kcal/mol over E-Cat to 16.2kcal/mol over E-Cat/Z280 which indicates that Z280 facilitated the increased cracking of naphtha-range species to light olefins

Reactivity of naphtha fractions for light olefins production

The catalytic cracking of naphtha fractions for propylene production was investigated under high severity catalytic cracking conditions (high temperatures and high catalyst to oil ratio). Straight run naphtha and cracked naphtha along with a with proprietary catalyst were used, and reaction was carried out using a catalyst to oil ratio (C/O) of 3–6 at 600–650 °C and 1 atm in a micro activity testing (MAT) unit. The results from this experiments show that light cracked naphtha (LCN) gave the highest propylene yield of 18% at 650 °C, and that propylene yield depends on the naphtha fraction being used as feed. The trend for reactivity and propylene yield was as follows: light cracked naphtha > heavy straight run naphtha > light straight run naphtha > heavy cracked naphtha.

Improved catalytic cracking performance of USY in the presence of metal contaminants by post-synthesis modification

It is well known that pores in catalysts larger than reactant molecules in dimension can ease flow resistance and enhance desorption of the molecules. In this work, mesoporosity was introduced into ultra-stable Y zeolite (USY) via a soft-templating method and the resulting zeolite was applied for preparation of fluid catalytic cracking (FCC) catalysts. The zeolite was extensively characterized by methods including N2 sorption, X-ray Diffraction (XRD), magic angle spinning nuclear magnetic resonance (MAS NMR), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Results show that the resulting zeolite pores were highly interconnected. Aluminum atoms were re-distributed within the framework while the crystallites were maintained. The effect of contaminant metals (vanadium and nickel) on the activity and product distribution of the prepared catalysts containing modified zeolite was investigated using the micro activity test (MAT). Compared with the parent USY, the modified USY exhibited higher yields of light oil products, much lower coke formation, and lower dry gas yield. Furthermore, the catalysts containing modified USY-10 possessed a higher stability toward metal deactivation than the parent USY. This improved catalytic behavior could be attributed not only to the enhanced diffusion and faster desorption of the adsorbed oil molecules within the pores, but also to the increased accessibility to the acidic sites due to well interconnected pore structures and the large mesopore size.

Catalytic cracking of Arabian Light VGO over novel zeolites as FCC catalyst additives for maximizing propylene yield

Catalytic cracking of vacuum gas oil (VGO) was carried out in a microactivity test (MAT) unit. Commercial FCC USY catalyst (E-Cat) is used and modified by various zeolites with different pore structures, namely SSZ-74, SSZ-33, MCM-22, MCM-36, ZSM-5, TNU-9, IM-5, and ferrierite to enhance propylene yield. Adding zeolite additives to E-Cat increased catalyst activity. The highest propylene yield of ∼11wt.% was achieved over ferrierite and MCM-36 compared with 7wt.% over E-Cat. An increase in light olefins yield over all additives was associated with a decrease in gasoline yield due to the cracking of gasoline-range reactive species (mainly olefins and iso-paraffins). Zeolite SSZ-74 showed a good enhancement in light olefins yield up to 21.3wt.% compared with 16.1wt.% over E-Cat. It is found that additives with lower ability to carry bimolecular reactions are more selective to light olefins. Gasoline quality was improved as the octane number increased over E-Cat with all additives except MCM-36.

Catalytic Cracking of Triglyceride-Rich Biomass toward Lower Olefins over a Nano-ZSM-5/SBA-15 Analog Composite

The catalytic cracking of triglyceride-rich biomass toward C2–C4 olefins was evaluated over a hierarchically textured nano-ZSM-5/SBA-15 analog composite (ZSC-24) under fluid catalytic cracking (FCC) conditions. The experiments were performed on a fully automated Single-Receiver Short-Contact-Time Microactivity Test unit (SR-SCT-MAT, Grace Davison) at 550 °C and different catalyst-to-oil mass ratios (0–1.2 g∙g−1). The ZSC-24 catalyst is very effective for transformation of triglycerides to valuable hydrocarbons, particularly lower olefins. The selectivity to C2–C4 olefins is remarkably high (>90%) throughout the investigated catalyst-to-oil ratio range. The superior catalytic performance of the ZSC-24 catalyst can be attributed to the combination of its medium acid site amount and improved molecular transport provided by the bimodal pore system, which effectively suppresses the secondary reactions of primarily formed lower olefins.

Synthesis and characterization of mesoporous zeolite Y by using block copolymers as templates

Mesoporous zeolite Y is directly synthesized using block copolymers (pluronic F127) as templates. The block copolymers guide the aluminosilicate gel to assemble into mesoporous zeolite under its excellent aggregation properties. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), IR spectra analyses (FT-IR), FTIR spectroscopy of adsorbed pyridine (Py-IR), and temperature-programmed ammonia desorption (NH3-TPD). The results indicated that Meso-USY prepared with templates had a dual mesopores and large mesopore volume of 0.20cm3g−1. The acid type over Meso-USY was also modified, and high Brønsted to Lewis ratio was obtained. Their catalytic performance was assessed in a micro-activity test unite at 733K using light diesel as material raw, Although the Meso-USY showed lower crystallinity and less total acid sites compared to Conv-USY, Meso-CAT prepared from Meso-USY presented excellent catalytic performance. Then, it can be concluded that the structural and textural properties of the mesoporous zeolite Y have considerable influence on the catalytic performance. The abundant mesopores volume and appropriate acidity are necessary for the excellent catalytic activity.

Catalytic cracking of polycyclic aromatic hydrocarbons with hydrogen transfer reaction

With the aim of enhancing oil refining processes based on fluid catalytic cracking (FCC), the catalytic cracking of polycyclic aromatic hydrocarbons (PAHs) was investigated using an FCC catalyst consisting of a rare earth ion exchanged USY zeolite. In these trials, model PAHs were dissolved in n-hexadecane and were fed into a fixed bed microactivity test reactor operating at 516°C. Reaction product analysis indicated very little cracking of the 2-ring PAH over the FCC catalyst, while in contrast the 3-ring PAH was highly reactive, and was rapidly converted into monocyclic aromatic hydrocarbons, 2-ring PAHs and coke. Tests using FCC catalysts with different rare earth loadings revealed that the loading amount has little effect on the conversion of the 3-ring PAH. In addition, catalysts containing USY zeolites with comparable unit cell sizes, and thus having comparable hydrogen transfer activities, exhibited similar catalytic activities for 3-ring PAH conversion, even though they contained different amounts of the rare earth metal oxide. This result suggests that the hydrogen transfer reaction plays an important role in 3-ring PAH conversion and that the main effect of rare earth loading is to maintain the hydrogen transfer activity of the catalyst by stabilizing the USY zeolite against steam deactivation. In summary, this study successfully demonstrated a potential FCC process for converting PAHs into useful light fractions without the necessity of employing a pressurized hydrogen atmosphere.

Utilization of exhausted dust from FCC flue gas as material for FCC catalyst preparation

In this paper, new matrix and corresponding fluidized catalytic cracking (FCC) catalysts were prepared by reutilizing the exhausted dust which was derived from fluidized catalytic cracking flue gas. The results showed that the new matrix has wider mesopore size distribution than pseudo-boehmite binder. With the increase of the additional amount of this new matrix, FCC catalyst possessed increased micro-activity test conversion of vacuum gas oil (VGO) from 68 % to 71 %. The catalytic cracking performance on a fixed fluidized bed unit showed that compared with CAT-1, the conversion of VGO on CAT-5 increased by 1.19 %, heavy oil yield and coke yield decreased by 2.16 and 1.65 %, respectively. Besides, the total liquid yield and light oil yield increased by 2.27 and 2.26 %, respectively. The reaction performance of CAT-3 and CAT-5 is obviously superior to CAT-1. The appropriate pore structures and crystallized Y zeolite component on this new matrix improve the cracking ability of FCC catalysts.

Co-processing of Dry Bio-oil, Catalytic Pyrolysis Oil, and Hydrotreated Bio-oil in a Micro Activity Test Unit

Fast pyrolysis technology is currently moving forward to commercialization, and demonstration plants are at the commissioning stage. The quality of bio-oil differs significantly from fossil fuels, and therefore, upgrading technologies are needed to improve the fuel properties of bio-oil. Co-processing of bio-oil in refinery fluid catalytic cracking (FCC) would have many economic advantages compared to other upgrading technologies because no essential modifications to the refinery are needed. However, because of its different chemical composition, the introduction of bio-oil into the FCC unit will introduce uncertainty to the refinery operation. In this paper, co-processing of dry thermal bio-oil, catalytic pyrolysis oil, and hydrotreated bio-oil was compared using a micro activity test (MAT) setup. The experiments show that the bio-oil concentration during co-processing should remain low to avoid high coke formation. Co-processing of dry bio-oil also resulted in a much lower liquid yield compared to catal...

The Influence of Temperature and Catalyst Additives on Catalytic Cracking of a Heavy Fuel Oil

The effects of reaction temperature and catalyst additives on the fluid catalytic cracking (FCC) products yield have been studied through cracking of a heavy fuel oil obtained from Tehran refinery. The catalytic performance was assessed using a commercial equilibrium USY FCC catalyst (E-Cat) in a fixed-bed micro-activity test unit. Two types of ZSM-5 zeolites with different SiO2/Al2O3 ratios together with MCM-41 were tested as additives. Different reaction temperatures of 550, 600 and 640°C were investigated for the corresponded E-Cat/Additives. MAT results showed that more propylene and the highest propylene to ethylene ratio can be obtained via E-Cat/MCM-41 at 550°C. Applying ZSM-5 zeolite led to enhancement in total olefins production. Different behaviors were observed using two ZSM-5 additives. Butenes production followed a similar fashion through all additives at the three temperatures tested.

Use of ZSM-5 catalyst in deoxygenation of waste cooking oil

AbstractThis study investigated the potential use of waste cooking oil (WCO) in the production of engine fuels and valuable chemicals via catalytic cracking. WCO was processed in its pure form and in a mixture with hydrotreated vacuum gas oil (HVGO). Catalytic cracking experiments were performed using a microactivity test (MAT) (simulation of the fluid catalytic cracking environment). In cracking over the standard fluid catalytic cracking equilibrium catalyst (FCC-ECAT), the oxygen contained in the feed was consumed in the formation of CO and CO