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- Biodiesel (2)
- DFT (2)
- Guaiacol hydrodeoxygenation (2)
- Hydrodeoxygenation (2)
- Kinetic modeling (2)
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- Methane as reductant (2)
- ZSM-5 zeolite (2)
- Bench reactor (1)
- Bifunctional catalysts (1)
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- Glycerol aromatization (1)
- Glycerol purification (1)
- Glycerol selective oxidation (1)
- Glycerol to aromatic hydrocarbon (1)
- Guaiacol deoxygenation (1)
- Improving catalyst stability (1)
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- Pt catalyst (1)
- Pt-Bi bifunctional catalyst (1)
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- Transesterification (1)
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Articles 1 - 9 of 9
Full-Text Articles in Catalysis and Reaction Engineering
Kinetics Of Glycerol Conversion To Hydrocarbon Fuels Over Pd/H-Zsm-5 Catalyst, Yang Xiao, Arvind Varma
Kinetics Of Glycerol Conversion To Hydrocarbon Fuels Over Pd/H-Zsm-5 Catalyst, Yang Xiao, Arvind Varma
Yang Xiao
The utilization of glycerol, primary byproduct of biodiesel production, is important to enhance process economics. In our recent prior work, it was shown that glycerol can be converted to hydrocarbon fuels over bifunctional catalysts, containing a noble metal supported on H-ZSM-5. Over Pd/H-ZSM-5 catalyst, an optimal ∼60% yield of hydrocarbon fuels was obtained. In the present work, based on experimental data over Pd/H-ZSM-5 catalyst, a lumped reaction network and kinetic model are developed. Using differential kinetic experiments over the temperature range 300–450°C, the rate constants, reaction orders, and activation energies are obtained for each reaction step. The predicted values match …
Kinetics Of Guaiacol Deoxygenation Using Methane Over The Pt–Bi Catalyst, Yang Xiao, Arvind Varma
Kinetics Of Guaiacol Deoxygenation Using Methane Over The Pt–Bi Catalyst, Yang Xiao, Arvind Varma
Yang Xiao
Using H2 as a reductant, catalytic hydrodeoxygenation (HDO) is typically used for upgrading bio-oils, generally produced from thermal degradation of lignin. In our recent prior work, methane was used to deoxygenate guaiacol over the Pt–Bi catalyst and was found to exhibit as good deoxygenation performance as hydrogen. In the present work, using methane as a reductant, detailed reaction pathways and kinetics of guaiacol deoxygenation are studied using differential and integral operating conditions. Kinetic parameters including rate constants and activation energies are determined for each individual reaction step. The model predicted values match experimental data well. Results from the present …
Conversion Of Glycerol To Hydrocarbon Fuels Via Bifunctional Catalysts, Yang Xiao, Arvind Varma
Conversion Of Glycerol To Hydrocarbon Fuels Via Bifunctional Catalysts, Yang Xiao, Arvind Varma
Yang Xiao
Utilization of byproduct glycerol improves biodiesel production in terms of both economics and sustainability. Conversion of glycerol to hydrocarbon (GTH) fuels is among the promising options, which provides additional renewable energy besides biodiesel and contributes further to independence from fossil fuels. In the present work, bifunctional catalysts (Pt/H-ZSM-5 and Pd/H-ZSM-5) were selected, prepared, characterized, and tested for GTH conversion. The addition of noble metals enhances aromatics’ yield, and both catalysts convert GTH fuels effectively. On the basis of the experimental observations and prior literature, it is proposed that GTH conversion follows sequential hydrodeoxygenation and aromatization steps. Under optimized conditions, ∼90% …
An Experimental And Theoretical Study Of Glycerol Oxidation To 1,3-Dihydroxyacetone Over Bimetallic Pt-Bi Catalysts, Yang Xiao, Jeff Greeley, Guomin Xiao, Zhi-Jian Zhao, Arvind Varma
An Experimental And Theoretical Study Of Glycerol Oxidation To 1,3-Dihydroxyacetone Over Bimetallic Pt-Bi Catalysts, Yang Xiao, Jeff Greeley, Guomin Xiao, Zhi-Jian Zhao, Arvind Varma
Yang Xiao
It is important to utilize glycerol, the main by-product of biodiesel, to manufacture value-added chemicals such as 1,3-dihydroxyacetone (DHA). In the present work, the performance of five different catalysts (Pt-Bi/AC, Pt-Bi/ZSM-5, Pt/MCM-41, Pt-Bi/MCM-41, and Pt/Bi-doped-MCM-41) was investigated experimentally, where Pt-Bi/MCM-41 was found to exhibit the highest DHA yield. To better understand the experimental results and to obtain insight into the reaction mechanism, density functional theory (DFT) computations were conducted to provide energy barriers of elementary steps. Both experimental and calculated results show that for high DHA selectivity, Bi should be located in an adatom-like configuration Pt, rather than inside Pt. …
Guaiacol Hydrodeoxygenation Over Platinum Catalyst: Reaction Pathways And Kinetics, Danni Gao, Yang Xiao, Arvind Varma
Guaiacol Hydrodeoxygenation Over Platinum Catalyst: Reaction Pathways And Kinetics, Danni Gao, Yang Xiao, Arvind Varma
Yang Xiao
Guaiacol represents a large fraction of lignin derived pyrolysis bio-oils. It was shown in our prior work that Pt has higher activity and stability for guaiacol hydrodeoxygenation as compared to other noble metal catalysts. In the present study, further theoretical and experimental investigations were conducted to reveal the reaction pathways and kinetics. For Pt/C catalyst in a fixed-bed reactor, the main liquid phase reaction products were phenol, catechol and cyclopentanone. Because cyclopentanone was typically not observed in the prior literature, a pathway for its formation was proposed and supported by density functional theory (DFT) calculations. By varying the space velocity, …
Catalytic Deoxygenation Of Guaiacol Using Methane, Yang Xiao
Catalytic Deoxygenation Of Guaiacol Using Methane, Yang Xiao
Yang Xiao
Guaiacol, produced by thermal degradation of lignin, represents a model compound for upgrading of fast pyrolysis bio-oils by deoxygenation. In our prior work, with Pt/C catalyst, such a process using H2 was studied. To overcome the high cost of H2, methane is used in this work to deoxygenate guaiacol. On Pt/C catalyst, in terms of guaiacol conversion and product distribution, methane is found to exhibit as good deoxygenation performance as H2. The lifetime of this catalyst, however, is short (<3 h). The lifetime of Pt–Bi/C catalyst is extended (no significant deactivation in 5 h), by addition of bismuth as a …
A Universal Procedure For Crude Glycerol Purification From Different Feedstocks In Biodiesel Production: Experimental And Simulation Study, Yang Xiao, Guomin Xiao, Arvind Varma
A Universal Procedure For Crude Glycerol Purification From Different Feedstocks In Biodiesel Production: Experimental And Simulation Study, Yang Xiao, Guomin Xiao, Arvind Varma
Yang Xiao
It is important to utilize crude glycerol, the main byproduct of biodiesel production, to manufacture high value-added chemicals. Since crude glycerol typically contains less than 65 wt % glycerol, purification is the first step for its utilization. Owing to the wide variety of triglycerides, alcohols, catalysts, and separation processes used in biodiesel production, crude glycerol composition varies widely, leading to different crude glycerol purifications. In the present work, we develop a universal procedure for crude glycerol purification, including as key steps initial microfiltration of the crude glycerol, saponification, acidification, phase separation, and biphasic extraction of upper- and lower-layer products. The …
Experimental And Modeling Study Of Continuous Catalytic Transesterification To Biodiesel In A Bench-Scale Fixed-Bed Reactor, Yang Xiao, Guomin Xiao
Experimental And Modeling Study Of Continuous Catalytic Transesterification To Biodiesel In A Bench-Scale Fixed-Bed Reactor, Yang Xiao, Guomin Xiao
Yang Xiao
A 500 h endurance test of continuous catalytic transesterification to biodiesel was conducted in a bench-scale fixed-bed reactor. A designed cylinder shape of KF/Ca–Mg–Al hydrotalcite catalyst was stable through the test with high catalytic activity and mechanical strength, converting palm oil to biodiesel with a conversion of more than 95%. Conditions effects on transesterification under relative high pressure (1.0 MPa) were investigated and a one-dimensional heterogeneous model of a fixed-bed reactor was developed to describe the reaction-mass transfer behaviors of continuous catalytic transesterification in a bench-scale fixed-bed reactor. With the given reactor size, optimum conditions were proposed as a LHSV …
Kinetics Of The Transesterification Reaction Catalyzed By Solid Base In A Fixed-Bed Reactor, Yang Xiao, Guomin Xiao
Kinetics Of The Transesterification Reaction Catalyzed By Solid Base In A Fixed-Bed Reactor, Yang Xiao, Guomin Xiao
Yang Xiao
Kinetics of the transesterification reaction catalyzed by solid base in a fixed-bed reactor was studied in this paper. The transesterification reaction between palm oil and methanol was catalyzed by KF/Ca−Mg−Al hydrotalcite solid base, which made it a complicated liquid−liquid−solid heterogeneous reaction. Isopropyl ether was used to obtain a homogeneous reactant system, and then liquid−liquid mass-transfer limitations were eliminated. Experimental results showed that, when the feed rate was faster than 0.3 mL/min, liquid−solid external diffusion mass-transfer limitations were negligible and, when the diameter of the catalyst particle was not larger than 0.18 mm, liquid−solid internal diffusion mass-transfer limitations could be neglected …