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Heterogeneous catalysts of supported metals are important for both liquid-phase and gas-phase chemical transformations which underpin the petrochemical sector and manufacture of bulk or fine chemicals and pharmaceuticals.

The kinetics of biomass pyrolysis is fundamental for exploring its mechanisms and optimizing its processes, which is helpful for designing its systems. The derivative Weibull mixture model was proposed for kinetic description of the simulated distribution energy model (DAEM) processes and distillers dried grains with solubles (DDGS) pyrolysis processes. The conversion rate data of these processes at different heating rates could be accurately described by the derivative Weibull mixture model. Moreover, the proposed model could effectively smooth the noises contained in the experimental conversion rate data of DDGS pyrolysis. The derivative Weibull mixture model separated DDGS pyrolysis reactions into several individual processes, and provided some data required for further isoconversional kinetic analysis. The predicted curves from the derivative Weibull mixture model allowed us to obtain the effective activation energies of DDGS pyrolysis, which varied significantly from 170 to 330 kJ mol

The new catalysts Pt/Ti3AlxC2Ty developed by a novel reduction method outperformed reference catalysts made by deposition–precipitation in the selective hydrogenation of furfural to furfuryl alcohol.

Acid-catalyzed aqueous-phase hydrolysis of cellulose was investigated over zeolite HY nanocrystals grafted on anantase titania nanofibres (HY-TiO2). H-exchanged NaY zeolite nanocrystals of controlled size (40–60 nm) were synthesized and deposited over TiO2 nanofibres prepared by hydrothermal treatment of anatase nanoparticles. The resulting materials were characterized by XRD, SEM, TEM, NH3-TPD and FT-IR, and evidenced a homogeneous distribution of HY nanocrystals across the TiO2 nanofibres. HY-TiO2 catalysts exhibited higher turnover numbers and selectivity to glucose than large (500 nm to 2 μm) unsupported HY nanoparticles; this performance enhancement is attributed to the greater accessibility of Bronsted acid sites in HY nanocrystals to cellulose particles. The importance of active site accessibility to β-1,4-glycosidic bond cleavage was highlighted by a significant increase in the rates of glucose and cellobiose hydrolysis (versus cellulose) over HY-TiO2-100. Engineering of zeolite particle size is a critical design parameter for the valorization of sterically-challenging cellulosic feedstocks.

The aim of this study was to investigate the potential of combined catalyst (ZSM-5 and CaO) for high quality bio-oil production from the catalytic pyrolysis of pinewood sawdust that was performed in Py-GC/MS and fixed bed reactor at 500 °C. In Py-GC/MS, the maximum yield of aromatic hydrocarbon was 36 wt% at biomass to combined catalyst ratio of 1:4 where the mass ratio of ZSM-5 to CaO in the combined catalyst was 4:1. An increasing trend of phenolic compounds was observed with an increasing amount of CaO, whereas the highest yield of phenolic compounds (31 wt%) was recorded at biomass to combined catalyst ratio of 1:4 (ZSM-5: CaO - 4:1). Large molecule compounds could be found to crack into small molecules over CaO and then undergo further reactions over zeolites. The water content, higher heating value, and acidity of bio-oil from the fixed bed reactor were 21%, 24.27 MJkg−1, and 4.1, respectively, which indicates that the quality of obtained bio-oil meets the liquid biofuel standard ASTM D7544-12 for grade G biofuel. This research will provide a significant reference to produce a high-quality bio-oil from the catalytic pyrolysis of woody biomass over the combined catalyst at different mass ratios of biomass to catalyst.

Isoconversional methods are commonly used to process the thermogravimetric analysis (TGA) data and to simultaneously obtain the effective activation energies for lignocellulosic biomass pyrolysis. ...

In organic synthesis, it is important to control the selectivity target product with high purity and reduce the cost of energy and equipment for separation. This study investigated supported gold catalysts on biochar-modified titanate-based nanofibers in order to regulate the catalytic performances by biochar content and surface properties. The catalysts were characterized by SEM, TEM, XRD, XPS, ICP-OES, UV-Vis to confirm their morphology, particle size distribution of Au NPs, crystal structures, oxidation state of Au and other key elements, real Au loading, and optical properties. In the test of selective oxidation of benzyl alcohol to benzaldehyde, the biochar modification could improve the selectivity toward benzaldehyde. Moreover, the influence of catalyst calcination conditions, reaction time, reaction atmospheres, reaction temperatures and solvent were systematically investigated. These results are useful for peer researchers in rational catalyst design.

Bio-oil derived from fast pyrolysis of lignocellulosic biomass is unstable, and aging would occur during its storage, handling, and transportation. The kinetic analysis of bio-oil aging is fundamental for the investigation of bio-oil aging mechanisms and the utilization of bio-oil as biofuels, biomaterials or biochemicals. The aging kinetic experiments of bio-oil from poplar wood pyrolysis were conducted at different aging temperatures of 303, 333, 353, and 363 K for different specified periods of time in capped glass vessels. The traditional method with two separate fittings was employed to fit experimental data, and the results indicated that the obtained kinetic parameters could not fit the experimental data well. An advanced approach for kinetic modeling of bio-oil aging has been developed by simultaneously processing experimental data at different aging temperatures and using the pattern search method. The aging kinetic model with the optimized parameters predicted the aging kinetic experimental data of the bio-oil sample very well for different aging temperatures.

Bio-oil from biomass pyrolysis is a promising alternative and clean source of biofuels, chemicals, and materials. Its chemical composition, physical and chemical properties, and multiphase behavior change over time, because of aging, which significantly affects its storage, handling, transportation, upgrading, and application. This Review focuses on studying bio-oil aging, and its outlook, primarily covering the following four components: (1) the chemical composition, physical and chemical properties, and multiphase behavior of bio-oil; (2) the indicators for measuring the degree of aging and aging characteristics, including physical and chemical properties change during long-term and accelerated aging of bio-oil; (3) the aging mechanisms and kinetics emphasizing the reactions during the aging process and different kinetic models based on different aging indicators; (4) the potential approaches to slowing bio-oil aging. This Review presents highlights in developing aging mechanisms and kinetics that will allow the reader to have an in-depth understanding of the effect of aging on bio-oil properties and the approaches to improve the resistance of bio-oil aging.

Pyrolysis is a promising and attractive way to convert lignocellulosic biomass into low carbon-emission energy products. To effectively use biomass feedstock with size distribution to produce biofuels, a comprehensive kinetic model of the process, occurring at particle level, is important. In this study, the population balance model (PBM)-distributed activation energy model (DAEM) coupled model is first time developed to predict biomass pyrolysis. The Population balance model is used to present the variable size distribution of solid, decomposed from virgin biomass to porous char. Two different kinetic models are embedded into the conservation equations of mass and energy. They are compared to demonstrate the prediction performance of heating-up time during the pyrolysis process of biomass with a normal size distribution. It is found that non-isothermal kinetics without and with DEAM capture the intra-particle temperature distribution. There is a noticeable difference of heating-up time between single and distributed particle size.

Three series of catalysts consisting of gold (Au), platinum (Pt), or gold-platinum bimetallic nanoparticles (NPs) with controlled sizes (Au NPs 10 &plusmn, 2 nm, Pt NPs 6 &plusmn, 2 nm) anchored on hierarchical micro-/meso-/macroporous silica were successfully developed and systematically evaluated for the selective oxidation of aromatic alcohols to their corresponding aldehydes. The catalysts were prepared by the sol-immobilization method using as-made Au NPs and/or Pt NPs colloids, the silica supports were prepared with controlled pore structures and the hierarchical porous structures of catalysts were created by controllable desilication via the alkaline solution of the metal colloids. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), and these results showed no synergistic effect between Au and Pt on boosting the catalytic performance, whereas they demonstrated a clear dependence of catalytic conversions and reaction rates on the structural porosity of Au-Pt bimetallic catalysts. Our findings could potentially inspire peer researchers and scientists to develop designer porous catalysts and processes in the selective organic conversions.

The kinetic compensation effect between the activation energy and the pre-exponential factor has extensively existed in the thermochemical conversion processes of lignocellulosic biomass. The research on the kinetic compensation effect in lignocellulosic biomass torrefaction has been insufficient yet. The torrefaction of the pinewood sample was experimentally investigated by thermogravimetric analysis (TGA) at five isothermal temperatures of 220, 250, 265, 280 and 295 °C. The reaction order model was used to analyze the isothermal torrefaction kinetics of lignocellulosic biomass, and the results showed that many sets of activation energy and pre-exponential factor could describe the experimental data at each temperature equally well and they excellently satisfied the kinetic compensation effect relationship. The linear regression lines of the kinetic compensation effect points at different temperatures intersected at one point, whose values corresponded to the obtained optimal kinetic parameters. A kinetic-compensation-effect-based method was developed and verified to determine the kinetic parameters of isothermal biomass torrefaction. Based on the optimal kinetic parameters, the thermodynamic parameters (including Gibbs free energy, enthalpy, and entropy) of biomass torrefaction processes at various temperatures were calculated and analyzed.

Py-GC/MS and thermogravimetric analysis were carried out to systematically explore product selectivity and kinetics of poplar sawdust catalytic pyrolysis over bi-metallic Fe-Ni/ZSM-5. The results showed that the Fe-Ni/ZSM-5 exhibited an additive effect on the production of monocyclic aromatic hydrocarbons compared to mono-metallic catalysts (Fe/ZSM-5 or Ni/ZSM-5). Fe-Ni/ZSM-5 further increased the yield of toluene (17.28 mg g

Catalytic fast pyrolysis is a prominent technology for yielding high quality bio-oil and chemicals from lignocellulosic biomass while the application of catalyst has been a hotspot for being capable to deoxygenate bio-oil and enhance its fuel properties. The fundamental reaction pathways in catalytic fast pyrolysis and potential routes of bio-oil and chemicals production from three major individual components are discussed at the early section of the review. The effect and potentiality of solid acid catalyst mainly zeolites, biomass particle size and catalyst loading ratio on the yield and quality of bio-oil are then emphasized. In addition, the lumped kinetic model and distributed activation energy model (DAEM), used to predict the thermal behavior of biomass components and energy calculation in catalytic pyrolysis are described. The recent advances in the understanding of catalytic co-pyrolysis of lignocellulosic biomass with hydrogen rich co-feeder from different sources are also presented. The progress with technical difficulties in catalytic pyrolysis is pointed out having an intention to produce high quality bio-oil. Finally, some challenges and perspectives of improving bio-oil quality through catalytic fast pyrolysis that will be significant approach in the future research work are presented.

The synergetic effects during co-pyrolysis of biomass and waste tire (WT) were investigated concerning the product distribution and reaction kinetics. Two biomass feedstocks were separately mixed with WT at different effective hydrogen/carbon ratio (H/Ceff), and analytical co-pyrolysis of mixtures was conducted using pyrolysis gas chromatography/mass spectroscopy at 500 °C. Product distributions were similar between different biomass feedstocks but varied significantly at different H/Ceff values. The percentage of hydrocarbons increased significantly when increasing H/Ceff, and the optimal H/Ceff was determined considering the correspondingly higher yield of polycyclic aromatic hydrocarbons and char residuals at higher percentage of WT. The experimental derivative thermogravimetric curves of mixtures at the optimal H/Ceff were compared with the calculated results based on kinetic analysis of three individual components using the distributed activation energy model. Significant synergetic effects were observed at the initial and final stages of the pyrolysis process.

In order to overcome the noise problem when analyzing the experimental thermogravimetric analysis data and obtain the temperature values at different heating rates for various conversions, a modified logistic mixture model, the combination of two modified logistic functions and a constant, has been presented for fitting all thermogravimetric analysis curves at different heating rates. The thermogravimetric analysis curves of sweet sorghum bagasse pyrolysis at three heating rates of 15, 25 and 35 K min −1 were analyzed. The modified logistic mixture model and logistic mixture model were used for fitting the experimental thermogravimetric analysis curves at all heating rates. The results have shown that the modified logistic mixture model fitted the experimental data better than the logistic mixture model. Making use of the data calculated by the modified logistic mixture model, the effective activation energy values as a function of conversion were obtained by means of the Friedman isoconversional method. The effective activation energies varied from 150 to 320 kJ mol −1 when the conversion ranged from 0.05 to 0.85, which indicated that the pyrolysis of sweet sorghum bagasse was a complex process.

Bio-oil, a promising candidate to replace fossil fuels, has received considerable attention for its sustainability, resource diversity and environmental benefits. Industrial production of bio-oil is urgently needed. In this study, a downdraft circulating fluidized bed reactor commercial-scale fast pyrolysis plant with biomass throughput of 1–3 t h− 1 is studied. Rice husk was processed at a fast pyrolysis temperature of 550 °C to evaluate the plant operation status. The system was continuously operated for 80.42 h. The thermal properties of the feedstock (rice husk), dust (separated from feedstock), char and heat carrier were analyzed and the bio-oil properties such as water content, pyrolytic water content, viscosity, density, pH, heating value, solid content and ash content were analyzed and presented. All the tested properties of the bio-oil meets the pyrolysis liquid biofuels standards in ASTM D7544-12 for Grade G biofuels, except for the water content of the bio-oil, which is slightly higher than that of Grade G biofuels. In energy balance analysis, the potential recovered energy of the three main products was 8.0 ± 1.1, 2.1 ± 0.1 and 5.3 ± 0.7 MJ kg− 1 for bio-oil, char and non-condensable gas, respectively, which shows that the largest portion of the energy in biomass was recovered in the bio-oil.

Torrefaction kinetics is fundamental for the theoretical investigation and industrial application of torrefaction processes. Most of biomass torrefaction kinetic studies focused on kinetic modelling under either isothermal or linear heating programs with one or several activation energies, which couldn't accurately reflect its reaction mechanisms. A distributed activation energy model (DAEM) was proposed to analyze logging residue torrefaction kinetics with a combined heating program at different temperatures. The model parameters were efficiently optimized by using the pattern search method. The results showed that the DAEM could excellently describe the experimental data of logging residue torrefaction at various conditions. The obtained activation energy distributions for logging residue torrefaction with the combined heating program at final temperatures of 240, 270 and 300 °C lay in the range of 154–172 kJ mol−1, 160–177 kJ mol−1 and 165–185 kJ mol−1, respectively. These findings indicated that major reactions occurring during torrefaction were the devolatilization and carbonization of biomass's hemicellulose constituents and partial decomposition of biomass's cellulose constituents. The experimental kinetic data of mesocarp fiber torrefaction at final temperatures of 220, 250 and 270 °C from the literature was also successfully described by the DAEM.

Modeling of lignocellulosic biomass pyrolysis processes can be used to determine their key operating and design parameters. This requires significant amount of information about pyrolysis kinetic parameters, in particular the activation energy. Thermogravimetric analysis (TGA) is the most commonly used tool to obtain experimental kinetic data, and isoconversional kinetic analysis is the most effective way for processing TGA data to calculate effective activation energies for lignocellulosic biomass pyrolysis. This paper reviews the overall procedure of processing TGA data for isoconversional kinetic analysis of lignocellulosic biomass pyrolysis by using the Friedman isoconversional method. This includes the removal of “error” data points and dehydration stage from original TGA data, transformation of TGA data to conversion data, differentiation of conversion data and smoothing of derivative conversion data, interpolation of conversion and derivative conversion data, isoconversional calculations, and reconstruction of kinetic process. The detailed isoconversional kinetic analysis of TGA data obtained from the pyrolysis of corn stalk at five heating rates were presented. The results have shown that the effective activation energies of corn stalk pyrolysis vary from 148 to 473 kJ mol−1 when the conversion ranges from 0.05 to 0.85.

The determination of the kinetic triplet including the activation energy, frequency factor, and kinetic mechanism function is a key objective in kinetic analysis of solid-state reactions like lignocellulosic biomass pyrolysis. The master plots method is usually used to determine the kinetic mechanism function once the activation energies as a function of conversion are estimated from an isoconversional method. A critical study of the master plots method has been performed by analyzing theoretically simulated processes with varying activation energies and frequency factors. The accuracy of the resulting kinetic mechanism function calculated by the master plots method is strongly dependent on the variation degree of the frequency factor with conversion and the conversion dependency of activation energy from isoconversional methods. The utilization of the master plots method without considering the variation degree of the frequency factor with conversion may result in misestimating kinetic mechanism function.

The bifunctional Ga/HZSM-5 catalyst has been proven having the capability to increase the selectivity of aromatics production during catalytic pyrolysis of furan and woody biomass. However, the reaction chemistry and kinetics of pyrolysis of herbaceous biomass promoted by Ga/HZSM-5 is rarely reported. Pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) analysis and non-isothermal thermogravimetric analysis at four heating rates were carried out to investigate the decomposition behavior and pyrolysis kinetics of corn stalk without and with Ga/HZSM-5. The effective activation energies for corn stalk pyrolysis were calculated by using the Friedman isoconversional method. The Py–GC/MS analysis results indicated that the Ga/HZSM-5 catalyst had a high selectivity toward producing the aromatic chemicals of xylene, toluene and benzene, whereas the major products from non-catalytic pyrolysis of corn stalk were oxygenated compounds. The presence of Ga/HZSM-5 could significantly reduce the effective activation energies of corn stalk pyrolysis from 159.9–352.4 kJ mol−1 to 41.6–99.8 kJ mol−1 in the conversion range of 0.10–0.85.

To ensure a sustainable future, it is imperative to efficiently utilize abundant biomass to produce such as platform chemicals, transport fuels, and other raw materials; hydrochar is one of the promising candidates derived by hydrothermal carbonization of biomass in pressurized hot water. The synthesis of “hydrochar-wrapped Ti3AlC2-derived nanofibers” was successfully achieved by a facile one-pot hydrothermal reaction using glucose as the hydrochar precursor. Meanwhile, cellulose and pinewood sawdust as raw materials were also investigated. Products were characterized by XRD, N2 adsorption-desorption isotherms, SEM, TEM and FT-IR to investigate their crystal structures, textural properties, morphologies, and surface species. In the adsorption test to remove Cd(II) and Cu(II) in aqueous solution, hydrochar-wrapped nanofibers outperformed pure nanofibers derived from Ti3AlC2, hydrothermal carbon derived from glucose and commercial activated carbon. Finally, the regeneration, sorption kinetics, and possible adsorption mechanism were also explored.

The first and nth order kinetic models are usually used to describe cellulose pyrolysis. In this work, the local sensitivities of the conversion and derivative conversion with respect to the frequency factor, the logarithm of the frequency factor, the activation energy and the reaction order for the first and nth order kinetic models are calculated by using the finite difference method. The results show that the sensitivities of the first and nth order kinetic models with respect to the activation energy and the logarithm of the frequency factor are significant, while the frequency factor and the reaction order affect the nth order kinetic model slightly. Compared with the frequency factor, the natural logarithm of the frequency factor is a better choice in the parameter estimation of the first and nth order kinetic models. Graphical Abstract: [Figure not available: see fulltext.]

To explore the mechanism for hydrodeoxygenation (HDO) of bio-oil, which contains large compounds that share similar molecular structures of phenyl ring with oxygen-containing functional groups, guaiacol as a typical model compound of lignin-derived bio-oil was hydrotreated at 150–350 °C under 3–7 MPa (H2) using the synthesized zirconia-supported Rh catalyst in a batch reactor. With Rh/ZrO2 catalyst, guaiacol can be completely converted where reaction temperature plays a decisive role and significantly affects the degree of hydrogenation. HDO Process was optimized with insight into effects of different reaction parameters, including H2 pressure, reactant concentration, reaction time and temperature, on the whole process of HDO and formation of undesired oxygen-contained products. The optimum reaction conditions were 5 wt% guaiacol, 300 °C and 7 MPa in which guaiacol could be completely deoxygenated with 87. 7 mol% oxygen-free product of cyclohexane in 3 h and the desired O/C and H/C ratios of products were obtained. A specific reaction network including three main steps: “guaiacol → 1-methyl-1,2-cyclohexanediol → cyclohexanone and cyclohexanol → completely deoxygenated compounds of cycloalkanes”, was deduced by a comprehensive study on different reaction parameters and a typical key reaction network for HDO of lignin-derived bio-oil is proposed based on model compounds studies. Kinetic model for HDO of guiaacol with the Rh/ZrO2 catalyst was proposed based on the credible pathway and it fits well to a pseudo-first-order kinetic model that the R2 values obtained for the fittings were all above 0.98 at four temperatures. At low temperature of 150 °C, the kinetically relevant step is hydrogenation of the aromatic ring, yielding 90 mol% 1-methyl-1,2-cyclohexanediol, while at high temperature (≥300 °C), the kinetically relevant step is the complete deoxygenation of oxygen-containing functional groups which mainly yields cyclohexane. These results would be helpful to further understand the HDO mechanism of lignin-derived bio-oil, and the excellent performance of Rh/ZrO2 demonstrated its potential application in bio-oil hydrodeoxygenative upgrading process.

The kinetic and thermochemical models for poplar wood torrefaction were developed in the present work. The torrefaction kinetic model satisfactorily fitted the experimental thermogravimetric analysis (TGA) data of poplar wood torrefaction and provided a coherent description of the evolution of torrefaction volatile and solid products in terms of a set of identifiable chemical components and elemental compositions. The torrefaction thermochemical model described the thermochemical performance of poplar wood torrefaction processes. The results from the kinetic and thermochemical models for poplar wood torrefaction showed that (1) high temperature increases the evolution rate of torrefaction products, and favors the formation of torrefaction volatiles; (2) the heating rate has a slight effect on evolution for torrefaction process; (3) the mass and energy yields of torrefaction products are significantly influenced by both torrefaction temperature and residence time; (4) the heat of torrefaction reaction is mostly endothermic with a relatively small amount (less than 10% of the raw material energy content); (5) for the overall torrefaction processes, the sensible and latent energy of torrefaction products accounts for 5–18% of the total energy input and the remaining energy input transfers into the energy contents of torrefaction products. This work provides a theoretical guidance for future evaluation and optimization of woody biomass torrefaction systems/processes, and thereafter for the industrial application of woody biomass thermochemical conversion.

Naturally occurring AAEMs in biomass exhibit detrimental effects to biomass pyrolysis as producing less oil with lower quality. Acid pretreatments are cheap and effective methods for mitigating AAEMs effect, thus improving the pyrolysis performance. In the current study, a combination of different experiment techniques and theoretical kinetic analysis was conducted to systematically compare the effects of both acid infusion and washing pretreatments. By utilizing Py-GC/MS system, the product distribution from pyrolysis of raw and acid pretreated corn stovers was obtained. Compared to that of raw corn stover, significant reduction of char and improvement of sugars, especially levoglucosan (55% yield based on cellulose), from pyrolysis of acid washed corn stover were achieved because of the thorough removal of AAEMs in corn stover. As for acid infused corn stover, maintaining reaction in acid buffer condition (3~5 wt% acid infusion) kept the sugar yield at relatively high level. Further increase of acid infusion over 5 wt% resulted in strong dehydration reaction of sugars and sharp decrease of phenolic compounds. The DTG pattern and the key kinetic parameters of corn stover dramatically changed with acid pretreatment. Strong condensation reaction between cellulose and lignin in acid infused corn stover were also suggested by kinetic analysis. Besides, the evolution of major phenolic monomers from lignin component versus temperature was revealed by TG/PI-TOF-MS system. As for acid pretreated corn stover, the agglomeration associated with the increase of char production were further ascribed to the enhanced polymerization of vinyl-phenols and other simple phenols. Overall, the study provides insights into the fast pyrolysis behavior of acid pretreated biomass for producing high-quality bio-oil and value-added chemicals.

The exponential temperature change in nonisothermal kinetic analysis is usually used in the experimental investigation of biomass pyrolysis kinetics. In this paper, the applying of exponential temperature change for nonisothermal kinetics of thermally stimulated processes is discussed. Two approximations for the temperature integral occurring in nonisothermal kinetics with exponential temperature program are proposed. These approximations are more accurate in the evaluation of the integral than Gorbachev approximation. Based on the newly proposed approximations, the corresponding integral methods for nonisothermal kinetics with exponential temperature change have been developed. A systematic analysis of the relative errors involved in the kinetic parameters determined from these integral methods has been carried out, the results indicate that the proposed integral methods are more accurate than Gorbachev integral method. It is expected that the results will be helpful for the kinetic analysis of biomass pyrolysis with exponential temperature program.

Non-isothermal thermogravimetric analysis (TGA) at four heating rates of 10, 20, 30 and 40 K min−1 under oxidative atmosphere was employed to investigate the characteristics of microalgae residue oxidative pyrolysis. The double distributed activation energy model (DAEM) was used to analyze the oxidative pyrolysis kinetics of microalgae residue and the simulated annealing method was employed for the estimation of the model parameters. The results showed that the double DAEM could describe the kinetic experimental data of microalgae residue oxidative pyrolysis very well whilst the simulated annealing method was effective for determining the kinetic parameters of the double DAEM. The kinetic process of microalgae residue oxidative pyrolysis could be considered as two partially overlapped pseudo-sub-processes. The mean values of activation energy distributions were 179 and 259 kJ mol−1 for the first and second pseudo-sub-processes. The thermodynamic parameters of microalgae residue oxidative pyrolysis processes at the different heating rate were studied based on the obtained kinetic parameters.

In this study, rice husk and corn stalk have been pyrolyzed in an auger pyrolysis reactor at pyrolysis temperatures of 350, 400, 450, 500, 550, and 600 °C in order to investigate the effect of the pyrolysis temperature on the pyrolysis performance of the reactor and physicochemical properties of pyrolysis products (this paper focuses on char and gas). The results have shown that the pyrolysis temperature significantly affects the mass yields and properties of the pyrolysis products. The mass yields of pyrolysis liquid and char are comparable to those reported for the same feedstocks processed in fluidized bed reactors. With the increase of the pyrolysis temperature, the pyrolysis liquid yield shows a peak at 500 °C, the char yield decreases, and the gas yield increases for both feedstocks. The higher heating value (HHV) and volatile matter content of char increase as the pyrolysis temperature increases from 350 to 600 °C. The gases obtained from the pyrolysis of rice husk and corn stalk mainly contain CO2, CO, CH4, H2, and other light hydrocarbons; the molar fractions of combustible gases increase and therefore their HHVs subsequently increase with the increase of the pyrolysis temperature.

The pyrolysis processes of the selected combustible solid wastes (CSWs) including poplar wood, polyethylene (PE), paper, rubber, rice and polyethylene terephthalate (PET) were investigated by thermogravimetric (TG) analysis. The pseudocomponents of the six kinds of selected CSWs were determined based on Weibull mixture model. The DAEM reaction model was used to study the pyrolysis kinetics of the samples. The results showed that the pyrolysis temperature of selected CSWs was ranged from 413.15 to 979.14 K and the Weibull mixture model can reproduce the TG and DTG curves accurately. The TG curve can be understood as a sum of two or three parallel reactions, where each single reaction was represented by one Weibull model component. It was observed that there were three pseudocomponents for the poplar and paper samples. There was one pseudocomponent for the PE sample. However, the rubber, rice and PET samples had two pseudocomponents. The activation energy (E α ) changed from 120 to 225 kJ mol−1 in the range of the conversion rate from 0.15 to 0.85 for the six kinds of selected CSWs.

The viscosity of four aged bio-oil samples was measured experimentally at various shear rates and temperatures using a rotational viscometer. The experimental bio-oils were derived from fast pyrolysis of beech wood at 450, 500, and 550 °C and Miscanthus at 500 °C (in this work, they were named as BW1, BW2, BW3, and MXG) in a bubbling fluidized bed reactor. The viscosity of all bio-oils was kept constant at various shear rates at the same temperature, which indicated that they were Newtonian fluids. The viscosity of bio-oils was strongly dependent upon the temperature, and with the increase of the temperature from 30 to 80 °C, the viscosity of BW1, BW2, BW3, and MXG decreased by 90.7, 93.3, 92.6, and 90.2%, respectively. The Arrhenius viscosity model, which has been commonly used to represent the temperature dependence of the viscosity of many fluids, did not fit the viscosity-temperature experimental data of all bio-oils very well, especially in the low- and high-temperature regions. For comparison, the Williams-Landel-Ferry (WLF) model was also used. The results showed that the WLF model gave a very good description of the viscosity-temperature relationship of each bio-oil with very small residuals and the BW3 bio-oil had the strongest viscosity-temperature dependence.

This work studied the drying kinetics of the organic fractions of municipal solid waste (MSW) samples with different initial moisture contents and presented a new method for determination of drying kinetic parameters. A series of drying experiments at different temperatures were performed by using a thermogravimetric technique. Based on the modified Page drying model and the general pattern search method, a new drying kinetic method was developed using multiple isothermal drying curves simultaneously. The new method fitted the experimental data more accurately than the traditional method. Drying kinetic behaviors under extrapolated conditions were also predicted and validated. The new method indicated that the drying activation energies for the samples with initial moisture contents of 31.1 and 17.2 % on wet basis were 25.97 and 24.73 kJ mol−1. These results are useful for drying process simulation and industrial dryer design. This new method can be also applied to determine the drying parameters of other materials with high reliability.

To investigate the pyrolysis behaviour of microcrystalline cellulose (MCC) and obtain a high yield of hydrocarbon, MCC was extracted from rice straw. The modification of ZSM-5 by different molar concentrations (0.2 M, 0.4 M and 0.6 M) of NaOH solution was carried out. At the same time, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was performed without and with alkali-treated ZSM-5 maintaining biomass to catalyst ratio 0.25:1 at a fixed temperature of 500 °C. Results showed that the alkali treatment promoted aromatics and olefin by enhancing the mass transfer of molecules. A total hydrocarbon relative peak area of 87.71% was obtained when the ZSM-5 was treated with 0.4 M concentration of NaOH in comparison to other treated and parent ZSM-5. To assess the derivative conversion, thermogravimetric analysis (TGA) was studied at four effective heating rates of 5, 20, 35, and 50 K min−1. Furthermore, to calculate the activation energy of MCC, Kissinger-Akahira-Sunose (KAS) method was studied. Results revealed activation energy for MCC increased from 137.98 to 157.18 kJ mol−1 and decreased from 214.32 to 187.47 kJ mol−1 for without and with catalyst, respectively. This research will have a potential to ensure high yield hydrocarbon production from cellulose as well as other lignocellulosic biomass.