Fixed-bed Reactor System Research Articles

Insight into catalytic effects of alkali metal salts addition on bamboo and cellulose pyrolysis

Alkali metal compounds have vital influence on biomass pyrolysis conversion. In this study, cellulose, and bamboo catalytic pyrolysis with different alkali metal salts catalysts (KCl, K2SO4, K2CO3, NaCl, Na2SO4, and Na2CO3) were investigated in the fixed-bed reaction system. The effects of cations (K+ and Na+) and anions (Cl-, SO42−, and CO32-) on the evolution properties of biochar, bio-oil, and gas products were explored under both in-situ and ex-situ catalytic pyrolysis. Results showed that alkali metal salts facilitated the yields of biochar and gases at the expense of that of bio-oil. Alkali metal chloride and sulfate showed a weaker catalytic effect, while alkali metal carbonate greatly promoted the generation of gas products and increased the condensation degree of biochar. With the addition of K2CO3 and Na2CO3, cyclopentanones content was over 50% from cellulose catalytic pyrolysis, and phenols content (mainly alkylphenols) reached over 80% from bamboo catalytic pyrolysis. Moreover, solid-solid catalytic reactions with K2CO3 and Na2CO3 catalysts had an important role in strikingly promoting conversion of pyrolysis products, and the solid-solid and gas-solid catalytic reactions with alkali metal carbonate catalysts were stronger than those with alkali metal chloride and sulfate catalysts. Furthermore, the possible catalytic pyrolysis mechanism of alkali metal salts on biomass pyrolysis was proposed, which is important to the high-value utilization of biomass.

Intrinsic kinetics of steam methane reforming over a monolithic nickel catalyst in a fixed bed reactor system

The intrinsic kinetics of steam methane reforming were experimentally investigated using a monolithic nickel-based catalyst in a specially designed fixed bed system. All kinetic tests were performed under various operating conditions: steam to carbon ratio of 2 to 5, methane volumetric concentration in feed gas of 3 % to 9 %, temperature of 500 to 650 °C, and typical biogas compositions with N2 dilution (carbon dioxide 35.7–55.6 %, methane 44.4–64.3 %, with 86–91 % nitrogen dilution). A deconvolution process was applied during the rate calculation and the reaction orders with respect to different gases were determined, coupled with thermodynamic system analysis. The reaction mechanism was then proposed and a Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model was established, followed by kinetic parameter estimations for the model and a further model validation with experimental data. Based on the model, the intrinsic kinetic of SMR reaction using monolithic catalysts was described. The validity and feasibility of applying the faster approach for kinetic parameter estimation were demonstrated, and this work is the first demonstration of a complex reaction system. Also, the reaction mechanism appeared to show a suitably high correlation with alternative and more sustainable methane sources (i.e. biogas).

Investigation of Combustion and NO/SO2 Emission Characteristics during the Co-Combustion Process of Torrefied Biomass and Lignite.

This paper investigates the combustion characteristics and pollutant emission patterns of the mixed combustion of lignite (L) and torrefied pine wood (TPW) under different blending ratios. Isothermal combustion experiments were conducted in a fixed bed reaction system at 800 °C, and pollutant emission concentrations were measured using a flue gas analyzer. Using scanning electron microscopy (SEM) and BET (nitrogen adsorption) experiments, it was found that torrefied pine wood (TPW) has a larger specific surface area and a more developed pore structure, which can facilitate more complete combustion of the sample. The results of the non-isothermal thermogravimetric analysis show that with the TPW blending ratio increase, the entire combustion process advances, and the ignition temperature, maximum peak temperature, and burnout temperature all show a decreasing trend. The kinetic equations of the combustion reaction process of mixed gas were calculated by Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) kinetic equations. The results show that the blending of TPW reduces the activation energy of the combustion reaction of the mixed fuel. When the TPW blending ratio is 80%, the activation energy values of the mixed fuel are the lowest at 111.32 kJ/mol and 104.87 kJ/mol. The abundant alkali metal ions and porous structure in TPW reduce the conversion rates of N and S elements in the fuel to NO and SO2, thus reducing the pollutant emissions from the mixed fuel.

NiO–Ca9Co12O28 bifunctional phase change catalysts for biomass pyrolysis to hydrogen-rich syngas

In this study, the preparation of hydrogen-rich gases from improved pyrolysis-catalytic reforming system by industrial solid waste calcium carbide slag was investigated in a fixed-bed reaction system. The differences in biomass pyrolysis gas compositions and yields over the bifunctional phase change catalyst NiO–Ca9Co12O28 with different Ni doping ratios, pyrolysis temperatures, and calcium carbide slag doping ratios have been investigated, and a model for the mechanism of the redox reaction over the NiO–Ca9Co12O28 catalyst is proposed at the same time. The results of the study indicated that the maximum hydrogen production is 447.23 mL/gbiomass at 600 °C when the mass ratio of bamboo to calcium carbide slag is 5:9, which is 549.29% higher than that of pyrolysis of bamboo alone. The hydrogen volume concentration increased from 17.93% to 63.78%. This study provides a green and efficient route for high-value conversion of biomass and adsorption-enhanced reforming of solid waste for hydrogen production.

A Fixed-Bed Reaction System Packed with a Graphene/Multiwalled Carbon Nanotube Scaffold for the Oxidative Removal of Naproxen

A Fixed-Bed Reaction System Packed with a Graphene/Multiwalled Carbon Nanotube Scaffold for the Oxidative Removal of Naproxen

CO2 methanation over low-loaded Ni-M, Ru-M (M = Co, Mn) catalysts supported on CeO2 and SiC

The concentration of the major greenhouse gas CO2 is rapidly increasing in the atmosphere, leading to global warming and a range of environmental issues. An efficient circulation and utilization of CO2 is critical in the current environmental context. Methanation, an exothermic process, emerges as a critical strategy for effective CO2 utilization. On this front, there is a significant demand for rational design of catalysts that maintain high activity and methane selectivity over a wide temperature range (250–550 °C). The catalyst that can promise a consistent reaction even at 500 °C under an atmospheric pressure is thus obliged. The present study investigated bimetallic catalysts with SiC, which is known for its exceptional thermal conductivity, and CeO2, which is characterized by its CO₂ affinity, as base materials. We incorporated Ni-M and Ru-M (M = Co and Mn) as the active metals, each loaded at 2 %. Impressively, with merely 20 mg, the Ni-Co/SiC catalyst achieved a CO2 conversion rate of 77 % and CH₄ selectivity of 88 % at 500 °C, in a fixed-bed tubular reactor system with conditions of H2/CO2 = 4, a total flow rate of 70 ml min−1, and a steady GHSV of 12,000 h−1. Moreover, 2Ni-2Co/CeO2 catalyst demonstrated exceptional performance with a 76 % conversion of CO2 and a 83 % selectivity for CH4, all under identical conditions. The catalyst's durability was confirmed by a subsequent 40-hour stability test, which showed only a 3–5 % degradation. The developed catalysts were comprehensively characterized by BET/BJH, CO pulse chemisorption, H2-TPR, HAADF-STEM-EDS, SEM-EDS and XRD etc. to unveil their physicochemical and surface traits. It was found that Co and Mn, when integrated, effectively restrained the agglomeration of Ni and Ru particles, ensuring optimal metal dispersion on the support. In conclusion, our synthesized bimetallic catalysts shown a sustained catalytic capability, even in the high-temperature environment.

Role of cation in catalytic decomposition of ammonia over Ni supported zeolite Y catalysts

A series of nickel (Ni) catalysts were prepared using zeolites Y with different cation types (Na, Mg, Ca, Sr, Ba, Ce, and La) as supports and characterized by using XRD, BET, ICP-OES, XPS, and TEM, as well as NH3-TPD, CO2-TPD, and H2-TPR techniques. Their catalytic performances in decomposition of ammonia (NH3) to hydrogen (H2) were evaluated with a fixed-bed flow reactor system. The catalytic activities of the prepared catalysts for NH3 decomposition decreased in the order of Ni/SrY > Ni/BaY > Ni/LaY > Ni/CaY > Ni/NaY > Ni/MgY > Ni/CeY. The high activity of Ni/SrY catalyst may be attributed to its small Ni nanoparticle size, high basicity and strong interaction between highly dispersed Ni nanoparticles and SrY support. At 600 °C and GHSV of 9000 mLNH3·gcat−1·h−1, 98.0 % NH3 conversion with about 105.2 mmol min−1·gNi−1 H2 formation rate can be accomplished over Ni/SrY catalyst.

Response surface methodology (RSM)-based pyrolysis process parameter optimization for char generation from municipal solid waste (MSW) in a fixed bed reactor

Pyrolysis technology is a thermo-chemical process transforming any substance into valuable byproducts such as char, pyrolysis oil, and gas. The article outlines the production of char utilizing a fixed-bed reactor system to pyrolyze municipal solid waste (MSW) collected from a dumpsite in Guwahati City, India. Char (R1), pyrolysis oil (R2), and gas (R3) yield were used as the three responses in the pyrolysis experiment. Central Composite Design (CCD) recommended thirty pyrolysis experiment runs. According to CCD, the ideal pyrolysis conditions for a higher char yield were operating temperature of 250 °C, rate of heat of 10 °C/min, feed particle size of about 50 mm, and residence time of 180 mins. Under optimum conditions, the highest char yield was 72.62 %. A p-value of < 0.05 indicated that each process parameter was statistically significant. The operating temperature for pyrolysis was the most influential variable for achieving the highest char yield based on the F-value.

Equilibrium and experimental study on carbothermal reduction of sulfur dioxide to elemental sulfur

In order to solve the problem of low utilization value of flue gas desulfurization by-product, reduction of sulfur dioxide to elemental sulfur has emerged as a new process for resource utilization of SO2 with promising application prospects. Herein, the thermodynamic equilibrium calculation was carried out to study the influence of temperatures and C/SO2 molar ratios on the C-SO2 reaction. The effects of reaction temperature, carbon mass, and CO concentration on SO2 reduction by coke and activated carbon were studied on a fixed bed reaction system. The theoretical results demonstrated that the highest equilibrium S yield occurred when the C/SO2 molar ratio is 1, with higher ratios resulting in the formation of COS, CS2, and CO. Experimental data revealed that at temperatures below 700 °C, both SO2 conversion and S yield are notably low. As the temperature increases, both the conversion and yield gradually increase and approach the thermodynamic equilibrium value. The evolution of carbon surface chemical properties under the action of CO was analyzed by FTIR and XPS, which indicated that the presence of CO promotes the decarboxylation reaction, and then increases SO2 conversion and S yield. The conclusion of this study provides guidance for the development of high efficiency SO2 reduction technology.

Catalytic co-pyrolysis of cellulose over alkali and alkaline earth metal salts for levoglucosan production

A comprehensive study of alkali and alkaline earth metal (AAEM) salts including two different anions (Cl- and CH3COO-) in the catalytic pyrolysis of cellulose to produce levoglucosan (LG), bio-oil, and biochar were investigated. At the same time, the catalytic pyrolysis mechanism was also speculated. The thermogravimetric analyzer (TGA) and lab-scale fixed-bed reactor system were used to determine the thermal degradation process and the pyrolysis products of LG, bio-oil, and biochar. The optimized pyrolysis parameters were obtained by using Box-Behnken design-response surface method. According to the results, AAEM salts significantly boosted the yield of biochar, as well as greatly cut down the output of LG and bio-oil. The rank of effect on LG yield was as follows: CaCl2, MgCl2 > CH3COOK, CH3COONa > (CH3COO)2Mg, (CH3COO)2Ca > KCl, NaCl. Moreover, the addition of AAEM salts considerably dropped the activation energy E of cellulose pyrolysis as well as prompted microcrystalline cellulose pyrolysis under lower temperatures. This study was pivotal in deducing the pathway of cellulose pyrolysis, thereby offering critical insights to hasten the progress of biomass utilization.

ADSORPSI LOGAM Cr (VI) MENGGUNAKAN FILM KOMPOSIT CHITOSAN-CLAY DENGAN FIX-BED REAKTOR

Pollution caused by industrial waste is a serious problem that can endanger environmental health. One of the pollutants from industrial processes is heavy metal in the form of Cr (VI). Cr (VI) is a form of chromium that has high toxicity. Therefore, it is necessary to process Cr (VI), one of which is the use of chitosan-clay film as an adsorbent. Chitosan is an adsorbent that is very abundant in nature and is good for use in the adsorption process of some heavy metals but has a high solubility in acidic pH so the utilization of chitosan adsorbent is limited. This study aims to improve the mechanical stability and resistance of the chitosan film by compositing it with clay and to determine the ability of the chitosan-clay film to absorb Cr (VI) metal ions. Before the stability test, the purity of chitosan was tested using Fourier Transform Infrared (FTIR), and the DD value was 80.97% proving the chitosan made had met the standard. The film stability test was carried out by measuring the water absorption (DSA) and tensile strength of the film with various concentrations (2:0.75; 2.5:0.75; 3:0.75) (w/w). Based on the results of the study, the best results were obtained at variations in concentration (3:0.75), namely with a DSA of 142.90% and a tensile strength of 4.434 Mpa. Chitosan-clay adsorbent with the best stability test results was analyzed using the Scanning Electron Microscope (SEM) test to determine the structure and morphology, resulting in a film with larger and homogeneous pores. Furthermore, the adsorbent was applied in the adsorption process using a fixed bed reactor system by varying the concentration of waste 20, 30, and 40 mg/L and sampling time to 0, 15, 30, 45, and 60 minutes. The best metal ion removal efficiency of Cr (VI) was 89.92% with an initial concentration of 40 mg/l to a final concentration of 4.0327 mg/L at 30 minutes.

Analysis of the Effectiveness Factor in a Fixed-Bed Tubular Reactor System: Catalytic Dehydrogenation of Cyclohexanol

The modeling and simulation of the catalytic dehydrogenation process of cyclohexanol in a fixed-bed catalytic reactor is presented, leading to finding the relationship between the effectiveness factor, the Thiele modulus, and the Weisz–Prater modulus of the catalyst particles with respect to their axial and radial position, for which the external conditions of concentration and temperature around each particle were previously obtained by applying the material and energy balances in the catalyst bed considering a two-dimensional pseudo-homogeneous model with radial diffusion. Subsequently, the material balances are established in terms of the molar flux density and conversion, the energy balance in terms of the heat flux density, Fick’s law, Fourier’s law, and the differential form of the effectiveness factor non-isothermal for each particle chosen based on the proposed meshing. The Thiele modulus calculated for most of the points is between 0.8 and 0.25, with a tendency towards the lower limit, and the theoretical values established as the limit for the Thiele modulus fluctuate between 0.4&lt;Th&lt;4. Therefore, the effectiveness factor analyzed is between 1 and 1/Th; this indicates that both the reaction speed as well as the diffusion speed within the particle have an influence on the intraparticle process, which is confirmed by the calculation of the Weisz–Prater modulus whose values are not &lt;&lt;1 nor &gt;&gt;1. The results obtained are subjected to a statistical test leading to analyzing whether there are significant differences both in the Thiele modulus, as well as in the effectiveness factor with respect to the radius and length of the reactor. It has been determined that there are no significant differences between the effectiveness factor with respect to the radius of the reactor; however, according to the analysis of variance, there are significant differences in the effectiveness factor with respect to length and, likewise, there are significant differences in the Thiele modulus and the Weisz–Prater modulus with respect to radius and length.

Gasification performance of olive pomace in updraft and downdraft fixed bed reactors

This study aims to investigate the gasification potential of olive pomace with using different fixed-bed gasifier systems. Olive pomace as a dried form was supplied from a chemical industry plant working on olive oil soap, located in Izmir, Türkiye. After a complete characterization of olive pomace, gasification experiments by using fixed bed reactor systems were done at three different gasifier temperatures as 700, 800 and 900 °C. As a gasification agent, dry air was used with four different flowrates (0.4, 0.2, 0.1, 0.05 L/min) while pure oxygen experiments were carried out with a flow rate of 0.01 L/min. Syngas with H2 content of 48% and 45% (volumetric) were obtained in updraft and downdraft gasifiers, respectively, by using dried air as a gasifying agent. Heating value of syngas was around 12.4 MJ/Nm3. In the pure oxygen atmosphere, H2 contents of the syngas were measured as 53% and 39%vol. In the updraft and downdraft gasifiers. This paper presents the research results on the olive pomace gasification study as a part of a large-scale research project and discuss them in the context of hydrogen production from the fixed bed reactors.

Experimental study on hydrogen production characteristics of kaolin supported Ni catalyzed by steam gasification of citrus peel

This work aims to reveal the advantages of Ni/kaolin and to explore its influence on the gasification reaction characteristics in a fixed-bed reaction system. It was shown that 10 wt% was the optimum loading of Ni, when the carbon conversion efficiency was 84.54 % and the hydrogen yield was 36.79 mmol/gbiomass. According to the evolutionary behavior of gas products and kinetic analysis, it is known that when using 10 wt% Ni/kaolin, it accelerated the precipitation of volatiles and the reaction, greatly improved the carbon conversion efficiency of the reaction, and increased the instantaneous hydrogen yield from 4.26 mmol/(gbiomass·min) without catalyst to 5.12 mmol/(gbiomass·min) and the total yield of hydrogen was also increased to 60.70 mmol/gbiomass. The catalytic effect of 10 wt% Ni/kaolin was caused by the Ni(111) crystalline facets generation on the support surface, that could promote the cleavage of carbon–carbon and carbon-hydrogen bonds of tar.

Rational design for the fabrication of bulk Ni3Sn2 alloy catalysts for the synthesis of 1,4-pentanediol from biomass-derived furfural without acidic co-catalysts.

This study describes the rational design for the fabrication of bulk Ni3Sn2 alloy catalysts for the de/hydration-hydrogenation of biomass-derived furfural (FFald) to 1,4-pentanediol (1,4-PeD) without the acidic co-catalyst. The presence of both hydration active sites (Brønsted acid sites (Ni-SnOx)) and hydrogenation active sites (Ni0 or Ni-Sn alloy) in Ni3Sn2 alloy could be controlled by changing the pH of Ni-Sn solution during the preparation. Both active sites acted synergistically to catalyse the de/hydration-hydrogenation reactions of FFald to produce a high yield of 1,4-PeD in a batch reaction system at 433 K, 3.0 MPa H2 after 12 h. Bulk Ni3Sn2 obtained at pH of Ni-Sn solution of 8-10, hydrothermal temperature of 423 K for 24 h, and reduction with H2 at 673 K for 1.5 h demonstrated a high yield of 1,4-PeD (81-87%), which is comparable with that from previous work. A 76% yield of 1,4-PeD was also obtained when the reaction was carried out in a fixed-bed reaction system at 433 K, flow rate 0.065 mL min-1, H2 flow rate 70 mL min-1, and 3.29 wt% FFald in H2O/ethanol solution for 12 h. The activity of bulk Ni3Sn2 was maintained with 66% yield of 1,4-PeD even after 52 h reaction on stream. The fabricated bulk Ni3Sn2 alloy catalysts could be the promising heterogeneous Ni-Sn alloy-based catalysts for the catalytic conversion of biomass-derived-furanic compounds (e.g., FFald, furfuryl alcohol (FFalc), and 2-methylfuran (2-MeF)).

Deactivation of a steam reformer catalyst in chemical looping hydrogen systems: experiments and modeling

The utilization of real producer gases such as raw biogas or gasified wood for chemical looping hydrogen production implies the introduction of harmful contaminants into the process. Hydrogen sulfide represents one of the most challenging trace gases in the reformer steam iron cycle. The aim of the present work was an in-depth investigation of steam reforming with pure methane and synthetic biogas contaminated with selective concentrations of 1, 5 and 10 ppm of hydrogen sulfide. To validate the experimental data, the fixed-bed reactor system was modeled as one-dimensional pseudo-homogeneous plug flow reactor by an adapted Maxted model. In a preliminary thermodynamic study, the dry equilibrium composition was determined within a deviation of 4% for steam methane reforming (SMR) and 2% for synthetic biogas reforming compared to the experimental results. The impact of hydrogen sulfide on the reactivity of the catalyst was characterized by the residual methane conversion. The deactivation rate and extent is directly proportional to the concentration of H2S, as higher hydrogen sulfide concentrations lead to a faster deactivation and lower residual methane conversion. A comparison of the methane conversion as a function of sulfur coverage between experimental and simulated data showed good agreement. The predicted results are within <10% deviation for SMR and synthetic biogas reforming, except for sulfur coverages between 0.6 and 0.8. The temperature in the catalyst bed was monitored throughout the deactivation process to gather additional information about the reaction behavior. It was possible to visualize the shift of the reforming reaction front towards the bottom of the reactor caused by catalyst deactivation. The impact of sulfur chemisorption on the morphology of the steam reformer catalyst was analyzed by scanning electron microscope (SEM/EDS) and Brunnauer–Emmet–Teller techniques. SEM patterns clearly indicated the presence of sulfur as a sort of dust on the surface of the catalyst, which was confirmed by EDS analysis with a sulfur concentration of 0.04 wt%.

Ni-CaO bifunctional catalyst for biomass catalytic pyrolysis to produce hydrogen-rich gas

In this study, high-value conversion of biomass energy was achieved by catalytic pyrolysis of corn cob in a fixed-bed reaction system to produce hydrogen-rich gas. Specifically, the effects of synthesis temperature and catalyst metal ratio of Ni-CaO bifunctional adsorption catalyst on pyrolysis gas composition, yield, and hydrogen conversion were explored. The results show that the Ni1Ca7-750 catalyst has a uniform morphology, small particulate size, large specific surface area, and good pore size distribution at a synthesis temperature of 750 °C and metal ratio of Ni/Ca = 1/7. Under the conditions of pyrolysis temperature of 600 °C and catalyst/biomass = 1/1, the syngas percentage of Ni1Ca7-750 was 85.81 vol. %, and the total pyrolysis gas yield reached 661.63 mL/gbiomass with the highest H2 concentration (68.62 vol. %), hydrogen yield (450.15 mL/gbiomass) and hydrogen conversion (65.97 wt. %). The percentage of CO2 in the pyrolysis gas was 9.11 vol. %, which was 65.4 % lower than that of the corn cob pyrolysis blank group. Thus, this study provides a specific reference for catalytic pyrolysis technology for biomass resource development and clean production.

Investigation on mechanochemically modified calcium‐based adsorbent for flue gas HCl removal

AbstractFor purpose of reducing chlorine ions entering the wet flue gas desulfurazition (WFGD) tower to realize the WFGD waste water sequestration and the gypsum upgrading, a technical method of adsorbent injection into flue gas to remove HCl was proposed in this work. A new NaOH‐modified CaO (CA‐MC‐NA) was prepared by the mechanochemical ball milling method as a superior adsorbent for HCl removal in flue gas. The influence of particle size and Na doping on the dechlorination efficiency and chlorine capacity was investigated in a fixed bed reaction system. The experimental results demonstrated that the HCl removal performance is improved significantly under proper particle size and Na doping, as manifested by the experiment results that the chlorine capacity increases from 27.18 to 38.36 mg/g by simple mechanical ball milling, while it surprisingly reaches 75.36 mg/g by doping 5 wt.% NaOH. The surface physicochemical characteristics was explored by combined sample characterization of BET, XRD, SEM, elemental mapping, and particle size distribution. Dechlorination mechanism of the adsorbents were deduced and discussed. It shows that the mechanical ball milling process reduces the particle sizes to the submicron scale that induces the break and reconstruction of molecular interfacial bonds. It also increases the oxygen defects on the adsorbent surface. The doping of NaOH does not change the crystal structure of the dechlorinator, and Na ions can be chemically loaded over CaO in the form of ionic bonds. Free oxygen atoms or adsorbed oxygen molecules could combine with dissociated hydrogen atoms thus forming hydroxide radicals, which enhances the alkalinity of the adsorbent and boosts the removal of hydrogen chloride.

Fast co-pyrolysis of lignin with spent bleaching clay into monocyclic aromatic hydrocarbons over a novel low-cost composite catalyst

Improving the anti-coking performance of catalyst during lignin-catalyzed pyrolysis without affecting the selectivity of the monocyclic aromatic hydrocarbons (MAHs) is a challenge. In this paper, a low-cost composite catalyst (CSHZ) was prepared using calcined spent bleaching clay (CSBC) as a binder for HZSM-5 to resolve the issue. In order to evaluate the performance of the composite catalyst, an ex-situ fast catalytic co-pyrolysis experiment was performed in a fixed-bed reaction system with lignin and spent bleaching clay (SBC) as raw materials. The impacts of the temperature, CSBC-to-HZSM-5 ratios, raw material-to-catalyst ratios, and cycle-regeneration times on MAHs distribution, are then studied. The selectivity of CSHZ11 (CSBS-to-HZSM-5 ratio of 1:1) for MAHs in bio-oil reached 78.02 % at 550 ℃ and the raw material-to-catalyst ratio of 1:1, which exceeded those of HZSM-5 alone by 19.12 %. After 3 reaction-regeneration cycles, the catalytic activity of CSHZ11 for MAHs was 71.11 % of fresh catalyst. The characterization (TEM, Py-IR, TGA, etc.) of the catalysts (fresh and discarded) revealed that the addition of CSBC regulated the acidity and pore channels of HZSM-5 and inhibited the formation of catalyst graphite-like coke. This study demonstrates the feasibility of using binder modification to improve the anti-coking performance of HZSM-5. It also serves as a reference for the integrated utilization of SBC and lignin.

Experimental Determination on the Deactivation Kinetics of Residue Hydroprocessing in a Two-Stage Fixed Bed Loaded with HDM and HDS Catalysts

Residue catalytic hydrogenation was carried out in a two-stage downflow fixed-bed reactor system, with a HDM catalyst in the first stage and HDS catalyst in the second one, to mimic the industrial operation. The experiments were run at five sets of temperatures (395 °C (first reactor)/405 °C (second reactor), 400 °C/410 °C, 405 °C/415 °C, 410 °C/420 °C, and 420 °C/430 °C). It was found that the initial stage deactivation was mainly caused by the rapid deposition of coke. Gradually, the deposition of metal sulfides leads to a slow deactivation in the middle stage of operation. A deactivation model that considers the catalyst activity as a function of TOS was proposed and applied to the hydrotreating reaction. The deactivation parameters of HDCCR, HDS, HDNi, and HDV in the two reactors were obtained by fitting the experimental data at the outlet of the two reactors. According to the deactivation curves of catalysts, it is proposed that the deactivation of HDM catalyst is faster than that of HDS catalyst, and multi-bed hydrogenation can effectively increase the catalyst life.