ZSM-5/SBA-15复合催化剂制备及其对生物质热解制生物油

通过表面响应法,以Box-Behnken试验原理,对生物质（玉米秸秆）的非催化热解进行三因素试验,其中生物油产率为响应值,温度、升温速率、氮气流速为自变量,确定最大生物油产率的工艺参数进行催化热解。以硅酸四乙酯为硅源,通过水热合成法合成了复合催化剂ZSM-5/SBA-15,并进行玉米秸秆的微波催化热解产物分析。通过XRD、SEM、TEM、NH3-TPD进行催化剂表征,得到复合催化剂不仅具有介孔催化剂SBA-15的性质,且兼备微孔催化剂ZSM-5的性质。通过GC-MS分析,复合催化剂ZSM-5/SBA-15的加入,相比非催化热解烃类收率（6.42%）和酚类收率（39.65%）都有所增加。     

Catalytic pyrolysis of woody biomass in a fluidized bed reactor: Influence of the zeolite structure

Catalytic pyrolysis of biomass from pine wood was carried out in a fluidized bed reactor at 450 °C. Different structures of acidic zeolite catalysts were used as bed material in the reactor. Proton forms of Beta, Y, ZSM-5, and Mordenite were tested as catalysts in the pyrolysis of pine, while quartz sand was used as a reference material in the non-catalytic pyrolysis experiments. The yield of the pyrolysis product phases was only slightly influenced by the structures, at the same time the chemical composition of the bio-oil was dependent on the structure of acidic zeolite catalysts. Ketones and phenols were the dominating groups of compounds in the bio-oil. The formation of ketones was higher over ZSM-5 and the amount of acids and alcohols lower than over the other bed materials tested. Mordenite and quartz sand produced smaller quantities of polyaromatic hydrocarbons than the other materials tested. It was possible to successfully regenerate the spent zeolites without changing the structure of the zeolite.     

Pyrolysis of two different biomass samples in a fixed-bed reactor combined with two different catalysts

Pyrolysis of Euphorbia rigida and sesame stalk biomass samples with two selected commercial catalyst, namely DHC-32 and HC-K 1.3Q, have been conducted in a fixed-bed reactor. The effect of different catalysts and their ratio (5, 10 and 20% w/w) and pyrolysis temperature (500 and 750 °C) on the pyrolysis product yields were investigated and the obtained results were compared with similar experiments without catalyst. Bio-oil yield was increased comparing with non-catalytic experiments, at final pyrolysis temperature of 500 °C for both biomass samples and catalysts. In the catalytic experiments; when the temperature reached to 750 °C, although bio-oil product yield was reduced, the gas product yield was increased comparing with non-catalytic experiments.The pyrolysis oils were examined using spectroscopic and chromatographic analyses and then fractioned by column chromatography. Although the aliphatic and aromatic fractions were decreased and polar fraction was increased with catalytic pyrolysis of E. rigida; an opposite trend was observed in the sesame stalk pyrolysis oil, comparing with non-catalytic results.Obtained results were compared with petroleum fractions and determined the possibility of being a potential source of renewable fuels.     

Morphological and electrochemical properties of LiV3O8 cathode powders prepared by spray pyrolysis

Lithium trivanadate (LiV₃O₈) powders are prepared by spray pyrolysis. The precursor powders of LiV₃O₈ obtained by spray pyrolysis have spherical and rod-like morphologies. The LiV₃O₈ powders post-treated at 300 °C and 400 °C also have spherical and rod-like morphologies. However, the LiV₃O₈ cathode powders post-treated at 500 °C consist of only rod-like crystals. The crystalline structure of the precursor powders that were directly prepared by spray pyrolysis comprised of LiV₃O₈ layers along with a small amount of β-Li_0.33V₂O₅ impurity. The peak due to β-Li_0.33V₂O₅ persisted in the XRD spectrum even after post-treatment at 300 °C. On the other hand, crystalline structures of the powders post-treated at 400 °C and 500 °C comprised pure LiV₃O₈ layers. The initial discharge capacities of the LiV₃O₈ cathode powders decrease from 344 mAh g⁻¹ to 261 mAh g⁻¹ when the post-treatment temperatures increase from 300 °C to 500 °C. The discharge capacities of the LiV₃O₈ cathode powders obtained after post-treatment at 400 °C and 500 °C are approximately 255 mAh g⁻¹ and 236 mAh g⁻¹, respectively, after 40 cycles.     

含油污泥在ZSM-5沸石上催化热解产物特性

采用U型固定床管式炉研究了含油污泥在ZSM-5分子筛催化剂上的热解产物特性。发现在450℃下未使用催化剂热解时,GC-MS和GC测得的油泥热解油产物中的主要成分为烷烃和烯烃,芳烃含量较低;气体产物中主要为短链烃类,氢气产量较少。而在ZSM-5分子筛的催化作用下,热解油中芳香烃产量达到88.4%,气体产物中的氢气产量和短链烃类产量均明显增加。研究了400～550℃之间分子筛对含油污泥的催化效果,发现ZSM-5在500℃时催化效果最佳,油相产率达到65.6%,油相中的沥青质和胶质含量较低,芳香烃产量达到90.9%。通过热重和XPS分析发现分子筛上的积炭主要以多环芳烃焦炭的形式存在。     

Evaluation of catalytic pyrolysis of cassava rhizome by principal component analysis

Rhizome of cassava plants (Manihot esculenta Crantz) was catalytically pyrolysed at 500 °C using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) method in order to investigate the relative effect of various catalysts on pyrolysis products. Selected catalysts expected to affect bio-oil properties were used in this study. These include zeolites and related materials (ZSM-5, Al-MCM-41 and Al-MSU-F type), metal oxides (zinc oxide, zirconium (IV) oxide, cerium (IV) oxide and copper chromite) catalysts, proprietary commercial catalysts (Criterion-534 and alumina-stabilised ceria-MI-575) and natural catalysts (slate, char and ashes derived from char and biomass). The pyrolysis product distributions were monitored using models in principal components analysis (PCA) technique. The results showed that the zeolites, proprietary commercial catalysts, copper chromite and biomass-derived ash were selective to the reduction of most oxygenated lignin derivatives. The use of ZSM-5, Criterion-534 and Al-MSU-F catalysts enhanced the formation of aromatic hydrocarbons and phenols. No single catalyst was found to selectively reduce all carbonyl products. Instead, most of the carbonyl compounds containing hydroxyl group were reduced by zeolite and related materials, proprietary catalysts and copper chromite. The PCA model for carboxylic acids showed that zeolite ZSM-5 and Al-MSU-F tend to produce significant amounts of acetic and formic acids.     

The influence of a new fabrication procedure on the catalytic activity of ruthenium-selenium catalysts

A new procedure has been introduced to enhance catalytic activity of ruthenium-selenium electro-catalysts for oxygen reduction, in which materials are treated under hydrogen atmosphere at elevated temperatures. The characterisation using scanning electron microscopy, energy dispersive spectroscopy or energy dispersive X-ray spectroscopy exhibited that the treatment at 400 °C made catalysts denser while their porous nature remained, led to a good degree of crystallinity and an optimum Se:Ru ratio. The half cell test confirms feasibility of the new procedure; the catalyst treated at 400 °C gave the highest reduction current (55.9 mA cm⁻² at −0.4 V) and a low methanol oxidation effect coefficient (3.8%). The direct methanol fuel cell with the RuSe 400 °C cathode catalyst (2 mg RuSe cm⁻²) generated a power density of 33.8 mW cm⁻² using 2 M methanol and 2 bar oxygen at 90 °C. The new procedure produced the catalysts with low decay rates. The best sample was compared to the Pt and to the reported ruthenium-selenium catalyst. Possible reasons for the observations are discussed.     

Two stages catalytic pyrolysis of olive oil waste

A study of the pyrolysis of a waste from the extraction of olive oil has been carried out. The work objective was to characterize the char, tar and gaseous phases generated in the process for their possible utilization in energy generation. On the other hand, the influence of a set of variables has been studied, including the efficacy of the dolomite as catalyst. Finally, as previous step to the design of industrial installations, a kinetic study of the process (catalyzed and uncatalyzed), based in the generation of the principal gases, has been carried out. In the uncatalyzed process only the influence of temperature (400–900 °C) was studied. In the catalytic process, the influence of temperature (500–800 °C) and mass of catalyst (0–100 g) was studied. Also, the dolomite effectiveness as catalyst was evaluated. For this motive, consecutive experiments, without reactivating dolomite, were carried out (0–6 runs), and the yields of solids, liquids and gases were determined. An increase in reaction temperature leads to a decrease in char and tar yield and to an increase in the gas phase yield. When the catalyst is present and when the mass of the same is increased, an important decrease in the tar yield and a high increase in the gas phase yield are produced. This increment in the yield of gases is very significant in the case of hydrogen. In addition, the catalyst is very stable. Your activity remains constant during six consecutive pyrolysis experiments, without need to carry out the reactivation of the same. In the kinetic study carried out, it has been considered that the gases are formed through parallel independent first-order reactions, with different activation energy. For uncatalyzed experiments, the experimental data, once adjusted to the model, provided activation energies of 77.8, 38.6, 70.5 and 16.9 kJ mol^− 1 and the Arrhenius pre-exponential factors of 210.1, 9.9, 775.3 and 0.43 min^− 1 for H₂, CO, CH₄, and CO₂, respectively. For catalyzed experiments (following the same sequence) the activation energies were 15.6, 16.5, 12.7 and 23.3 kJ mol^− 1 and the Arrhenius pre-exponential factors 3.8, 1.4, 4.3 and 3.5 min^− 1.     

Catalytic pyrolysis of biomass for biofuels production

Fast pyrolysis bio-oils currently produced in demonstration and semi-commercial plants have potential as a fuel for stationary power production using boilers or turbines but they require significant modification to become an acceptable transportation fuel. Catalytic upgrading of pyrolysis vapors using zeolites is a potentially promising method for removing oxygen from organic compounds and converting them to hydrocarbons. This work evaluated a set of commercial and laboratory-synthesized catalysts for their hydrocarbon production performance via the pyrolysis/catalytic cracking route. Three types of biomass feedstocks; cellulose, lignin, and wood were pyrolyzed (batch experiments) in quartz boats in physical contact with the catalysts at temperature ranging from 400 °C to 600 °C and catalyst-to-biomass ratios of 5-10 by weight. Molecular-beam mass spectrometry (MBMS) was used to analyze the product vapor and gas composition. The highest yield of hydrocarbons (approximately 16 wt.%, including 3.5 wt.% of toluene) was achieved using nickel, cobalt, iron, and gallium-substituted ZSM-5. Tests performed using a semi-continuous flow reactor allowed us to observe the change in the composition of the volatiles produced by the pyrolysis/catalytic vapor cracking reactions as a function of the catalyst time-on-stream. The deoxygenation activity decreased with time because of coke deposits formed on the catalyst.     

Production of pyrolytic oils by catalytic pyrolysis of Malaysian refuse-derived fuels in continuously stirred batch reactor

Malaysian refuse derived fuels (RDF) as valuable fraction of waste recycling were pyrolyzed in continuously stirred batch rig at 450 °C in the presence and absence of catalysts. Different types of catalysts were used for upgrading both quantity and quality of pyrolysis products: Y-zeolite, equilibrium FCC, ZSM-5, Ni-Mo-catalyst, Co-Mo-catalyst, silica-alumina and alumina. Gas-chromatography, Fourier-transformed infrared spectroscopy, X-ray spectroscopy and other standardized methods were used for the identification of product. RDF pyrolysis has produced gases with yields of 15.7-27.8%, pyrolytic oils of 9.8-17.8% and water (9.2-12.8%) depending on the types of applied catalyst. Data showed that the volatile fraction (both gas and pyrolytic oils) slightly increased with the catalyst, especially for Y-zeolite and ZSM-5. Gases consisted of CO, CO₂, hydrogen and hydrocarbons. Main chemical compounds, such as aromatic, branched and non-branched in pyrolytic oils have been affected by catalysts, e.g. isomerization of main carbon frame and aromatization have been shown increasing in yields especially when Y-zeolite and ZSM-5 were applied. The phenol, benzene 1,3-diol and methyl-phenol content of pyrolytic oil obtained from non-catalytic pyrolysis decreased at 45.0%, 40.9% and 38.0%, respectively in the presence of Y-zeolite and at 39.4%, 36.9% and 26.9% over Co-Mo-catalyst compared to the catalyst free pyrolysis, respectively. Sulphur, nitrogen and chlorine were found as contaminants in pyrolytic oils, but their contaminants concentration could be significantly decreased by the use of catalysts. The activity of catalysts in the decrease of impurity followed the order of Ni-Mo-cat. > Co-Mo-cat. > Y-zeolite > FCC > ZSM-5 > Al₂O₃/SiO₂ > Al₂O₃. According to EDXRFS analysis, char consisted of impurities such as Ca, Ti, Fe, Cu, Zn and Pb elements.     

Enhancing propylene production from catalytic cracking of Arabian Light VGO over novel zeolites as FCC catalyst additives

The catalytic cracking of vacuum gas oil over fluid catalytic cracking (FCC) catalyst containing novel additives was investigated to enhance propylene yield. A conventional ZSM-5, mesoporous ZSM-5 (Meso-Z), TNU-9 and SSZ-33 zeolite were tested as additives to a commercial equilibrium USY FCC catalyst (E-Cat). Their catalytic performance was assessed in a fixed-bed micro-activity test unit (MAT) at 520 °C and various catalyst/oil ratios. The cracking activity of all E-Cat/additives did not decrease by using these additives. The highest propylene yield of 12.2 wt.% was achieved over E-Cat/Meso-Z compared with 9.0 wt.% each over E-Cat/ZSM-5 and E-Cat/TNU-9, at similar gasoline yield penalty. The enhanced production of propylene over Meso-Z is attributed to its mesopores that suppressed secondary and hydrogen transfer reactions and offered easier transport and accessibility to active sites. The lower enhancement of propylene over the large-pore SSZ-33 additive was due to its high-hydrogen transfer activity. Gasoline quality was improved by the use of all additives, as octane rating increased by 7-12 numbers for all E-Cat/additives.     

基于Py-GC/MS的玉米秸秆快速热解实验研究

以玉米秸秆为原料,利用Py-GC/MS设备在不同热解条件下进行快速热解实验,并对热解气相产物进行在线检测分析,考察了热解时间、热解温度及ZSM-5催化剂对玉米秸秆热解特性及热解产物分布的影响.实验结果表明:热解温度越高,热解反应越充分,且热解温度为550℃时对应的热解产物品质最高,其中芳香族化合物最高达28.3％;随着...     

Cracking of n-dodecane during supercritical state on HZSM-5 membranes

In the new generation of aircraft, jet fuel will serve as both an energy source and a heat sink for cooling through endothermic fuel reactions. Catalytic cracking of hydrocarbon fuel has proved to be potential for endothermic reaction. For this application, we have prepared ZSM-5 membranes as catalyst on the surface of stainless steel by secondary growth method. An optimized activation procedure of ZSM-5 membrane for catalytic cracking reaction is established by combining the results of catalytic reaction with thermal analysis (TGA and DSC). Taking n-dodecane as a model compound, the influence of silica alumina ratio (SAR = nSiO₂/Al₂O₃) of initial gel on the activity of hydrocarbon cracking reaction were studied. The results also demonstrate that the conversion of catalytic cracking reaction is much higher than that of pyrolysis during supercritical state. In addition, hydrogen molar ratio in gas production decreases with increasing the reaction temperature. Besides that, the optimum temperature for coke removal and the reduction of zeolite catalysts is between 550 °C and 600 °C.     

Enhancement of pyrolysis gasoline hydrogenation over Zn- and Mo-promoted Ni/γ-Al2O3 catalysts

Alumina-supported nickel catalysts modified by Zn and/or Mo were prepared and characterized using several techniques (XRF, BET, XRD, XPS, and TPR). The effect of Zn and Mo on catalytic hydrogenation activity was evaluated in hydrogenation of pyrolysis gasoline (PyGas) using styrene conversion for monitoring the activity trend in a fixed-bed reactor under the following conditions: temperature of 70–120 °C, H₂:PyGas volume ratio of 200:1, pressure of 2.8 MPa, and volume space velocity of 3.0 h^− 1. The promoted Ni-based catalysts exhibited excellent catalytic activity for the hydrogenation of PyGas. The styrene conversion doubled after the introduction of Zn and Mo.     

Pyrolysis characteristics of Oriental white oak: Kinetic study and fast pyrolysis in a fluidized bed with an improved reaction system

The kinetic parameters for the pyrolysis of Oriental white oak were evaluated by thermogravimetric analysis (TGA). The white oak was pyrolyzed in a fluidized bed reactor with a two-staged char separation system under a variety of operating conditions. The influence of the pyrolysis conditions on the chemical and physical characteristics of the bio-oil was also examined. TGA showed that the Oriental white oak decomposed at temperatures ranging from 250 to 400 °C. The apparent activation energy ranged from 160 to 777 kJ mol^− 1. The optimal pyrolysis temperature for the production of bio-oil in the fluidized bed unit was between 400 and 450 °C. A much smaller and larger feed size adversely affected the production of bio-oil. A higher fluidizing gas flow and higher biomass feeding rate were more effective in the production of bio-oil but the above flow rates did not affect the bio-oil yields significantly. Recycling a part of the product gas as a fluidizing medium resulted the highest bio-oil yield of 60 wt.%. In addition, high-quality bio-oil with a low solid content was produced using a hot filter as well as a cyclone. With exception of the pyrolysis temperature, the other pyrolysis conditions did not significantly affect the chemical and physical characteristics of the resulting bio-oil.     

Acid base catalyzed transesterification kinetics of waste cooking oil

The present study reports the results of kinetics study of acid base catalyzed two step transesterification process of waste cooking oil, carried out at pre-determined optimum temperature of 65 °C and 50 °C for esterification and transesterification process respectively under the optimum condition of methanol to oil ratio of 3:7 (v/v), catalyst concentration 1%(w/w) for H₂SO₄ and NaOH and 400 rpm of stirring. The optimum temperature was determined based on the yield of ME at different temperature. Simply, the optimum concentration of H₂SO₄ and NaOH was determined with respect to ME Yield. The results indicated that both esterification and transesterification reaction are of first order rate reaction with reaction rate constant of 0.0031 min^− 1 and 0.0078 min^− 1 respectively showing that the former is a slower process than the later. The maximum yield of 21.50% of ME during esterification and 90.6% from transesterification of pretreated WCO has been obtained. This is the first study of its kind which deals with simplified kinetics of two step acid-base catalyzed transesterification process carried under the above optimum conditions and took about 6 h for complete conversion of TG to ME with least amount of activation energy. Also various parameters related to experiments are optimized with respect to ME yield.     

生物质热解利用中主要催化剂的研究进展

催化热解目前逐渐成为生物质转化利用技术的主要研究方向,相比常规热解,催化热解可以对生物油进行有效提质并且定向产生高值化产品。本文通过对近年来新兴的催化剂进行综述,包括分子筛类催化剂（ZSM-5、HZSM-5、USY等）、炭基催化剂、金属氧化物、白云石、整体式催化剂等,了解了目前生物质热解利用中催化剂领域内的最新研究进展。文中指出,良好的催化剂是保证反应顺利进行的关键,不同催化剂定向产生的高值化产品也有所不同,因此催化剂的正确选择对于生物油的提质起着重大作用。根据目前领域内所研究内容,本文还对各类催化剂的优缺点、产物特性进行了详细比较,并针对该技术现有问题提出了部分建议并进行展望,为以后生物质热解领域催化剂的研究提供了重要的理论依据。     

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition met-alion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygena-tion (Edeoxygenation),lightweight (Elightweight) from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Elightweight of CTA pyrolysis volatiles over USY is 9.65％,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85％.Additionally,the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions (Mo,Co) and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY (4032 mg·kg-1),Co/USY (4363 mg·kg-1) and Mo/USY (4953 mg·kg-1) were increased by 27.03％,38.19％ and 54.78％,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.     

Low-Temperature SCR of NO with NH3 over USY-Supported Manganese Oxide-Based Catalysts

A series of catalysts of manganese oxide, manganese–cerium and iron–manganese oxide supported on USY (ultra-stable Y zeolite) were studied for the low-temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. It was found that MnO_x/USY have high activity and high selectivity to N₂ in the temperature range 80-180 °C. The addition of iron and cerium oxide increased NO conversion significantly although the single-component Fe/USY and Ce/USY catalysts had low activities. Among the catalysts studied in this work, the 14% Ce-6% Mn/USY showed the highest activity. The results showed that this catalyst yielded nearly 100% NO conversion at 180 °C at a space velocity of 30 000 cm³ g^-1 h^-1. The only product is N₂ (with no N₂O) below 150 °C. The effects of the concentration of oxygen, NO and NH₃ were studied and the steady-state kinetics were also investigated. The reaction order is 1 with respect to NO and zero with respect to NH₃ on the 14% Ce-6% Mn/USY catalyst at 150 °C.     

The role of Fe species in the pyrolysis of Fe phthalocyanine and phenolic resin for preparation of carbon-based cathode catalysts

Pyrolysis of a mixture of Fe phthalocyanine and phenolic resin (FePc/PhRs) was studied to clarify the details of the preparation protocol of nitrogen-doped carbon-based materials for cathode catalysts in polymer electrolyte membrane fuel cells. TEM images show that nanoshell carbon is formed by the pyrolysis of FePc/PhRs in the temperature range of 600-800 °C. The optimum pyrolysis temperature for the FePc/PhRs mixture was 600 °C, where moderate conductivity and high nitrogen content of the prepared carbon were both satisfied. This catalyst showed a promising fuel cell performance with 1.01 V open-circuit voltage and 0.33 W cm⁻² maximum output, at 0.2 MPa absolute pressure and 80 °C. A detailed study of the carbonization process suggests that the presence of Fe species during carbonization process contributes to higher nitrogen content and growth of nanoshell structure of the resulting carbon.