壳类生物质与煤共液化的研究

以核桃壳和褐煤为研究对象,系统考察了核桃壳/煤质量配比、原料/四氢萘溶剂质量比、反应温度、反应时间及催化剂对共液化效果的影响。结果表明,当核桃壳/煤质量配比为50/50,原料/四氢萘溶剂比例为1/10,反应温度300℃和反应时间为31min时,可获得较好的共液化效果。碳酸钠与硫铁催化剂对核桃壳与煤的共液化均具有明显的催化作用,转化率和油产率可获大幅提高。核桃壳与煤的共液化存在明显协同作用,且这种作用在催化剂条件下更明显。     

Pt/HZSM-5水相重整山梨醇合成生物汽油的研究

考察了Pt/HZSM-5载体的酸性(硅铝比)、反应温度、反应压力、反应时间等因素对水相重整山梨醇合成生物汽油反应的影响。结果表明:在载体的硅铝比为38、反应温度260℃、压力5.0MPa、反应时间8h的条件下,该反应的总转化率高达95%,烷烃产物中C_(5+)的选择性接近90%,其中异构烷烃的选择性大于50%。     

固体超强酸催化微晶纤维素水解制备乙酰丙酸

乙酰丙酸是一种重要的平台化合物,其应用十分广泛。研究发现,多种固体酸可以催化微晶纤维素合成乙酰丙酸,其中固体超强酸SO42-/Ti O2催化效果最佳,通过BET比表面积,XRD,NH3-TPD和元素分析等手段对催化剂性质进行了表征。该研究以SO42-/Ti O2为催化剂,考察了反应时间、反应温度、催化剂用量对乙酰丙酸收率的影响,并使用GC对反应产物进行了分析。在反应温度为210℃,反应时间为1h,SO42-/Ti O2催化剂的用量为纤维素质量的2.5%时,乙酰丙酸的收率为68.5%。     

香蕉假茎多元醇液化过程中纤维素的性能表征

在硫酸催化剂作用下对香蕉假茎进行聚醚多元醇液化,液化温度为150℃,采用单因素分析和正交试验方法研究液固比、时间、催化剂用量对残渣中纤维素含量的影响,采用FT-IR,TG和X射线衍射分析香蕉假茎、残渣及香蕉假茎纤维素。结果表明,残渣中纤维素含量在液化过程中随液固比的增大、时间的延长以及催化剂用量的增加先上升后下降;正交试验确定的最佳液化工艺为液固比12∶1、液化时间60 min、催化剂用量2.5mmol/g(催化剂摩尔数/香蕉假茎质量),残渣中纤维素含量为65.37%;残渣与原料的红外相比,木质素特征吸收峰基本消失;X射线衍射分析得到残渣和纤维素的结晶度分别为51.96%和62.37%,高于原料结晶度的44.83%;同时TGA表明,残渣与纤维素的热稳定性高于原料,即纤维素含量的增加提高了残渣的热稳定性,SEM显示在香蕉假茎表面有明显的降解反应发生。     

塑料和木屑的共液化以及催化液化实验研究

在温度为613～693K、压力为20～30MPa的条件下,以去离子水为溶剂在1L间歇式高压反应釜中对塑料和木屑进行共液化研究,实验考察了反应时间、溶剂填充率、温度、催化剂对液化行为的影响。结果表明:木屑的加入能降低塑料液化对高温的要求,共液化能获得较高的液化油收率。在未添加催化剂的情况下,共液化反应在653K的温度下油收率达最大值24.0%,转化率达83.5%,油的热值为44.6MJ/kg。催化剂的使用能降低反应所需要的温度并获得较高的液化油收率以及转化率。研究发现,HZSM-5分子筛的催化作用最为明显。     

稀土固体超强酸SO42-/SnO2-CeO2催化合成生物柴油

以工业棕榈酸和甲醇为原料,采用溶胶-凝胶法制备稀土固体超强酸催化剂SO42-/SnO2-CeO2,催化合成生物柴油。考察了稀土氧化铈添加量、焙烧温度、焙烧时间、硫酸浓度、醇酸质量比、催化剂用量和反应时间对酯化反应的影响。结果表明,当氧化铈添加量为5%时,在2.0 mol/L硫酸浸渍后,于550℃下焙烧3 h制备的催化剂性能最好。正交试验结果表明,合成生物柴油的优化条件为醇酸质量比为15∶25,催化剂用量为棕榈酸质量的4%,反应时间为4 h,在此条件下,酯化率为95.4%。经GC-MS分析,酯产物主要为直链十六烷酸甲酯和10-十八碳烯酸甲酯。     

松木屑乙二醇/甲醇复合溶剂液化及液化产物分析

以松木屑为原料,氢氧化钠为催化剂,乙二醇/甲醇复合溶剂为液化剂,考察了溶剂体积比(乙二醇/甲醇)、催化剂用量、液化温度、液化时间对液化转化率的影响,得到了较佳的液化条件:溶剂比(乙二醇/甲醇)50/150,NaOH用量为2 g、反应温度为320℃、液化时间为10 min,该条件下液化转化率为94.5%。利用GC-MS对液化油进行分析,结果显示,液化油组成非常复杂,主要含有烃、醇、醛、酮、酸、酯、酚类等物质。利用红外光谱对松木屑及其液化残渣和液化油进行了分析,分析表明,液化残渣中含有较多的木质素及其降解产物的缩合物,液化油中羟基含量较多。     

高酸值油料一步法制备生物柴油研究

以酸值123.04 mg KOH/g的棕榈油脱臭馏出物(PFAD)为原料,在带压反应器中,用浓硫酸为催化剂,采用一步法催化酯化反应制备生物柴油。重点研究反应温度、反应时间、催化剂用量和醇油比等因素对酯化和酯交换反应的影响。结果表明,提高反应温度能促进酯化反应和酯交换反应,使高酸值原料经一次反应直接转化为目的产物——脂肪酸甲酯,从而缩短制备流程,降低成本,强化酯化反应进行,提高脂肪酸甲酯收率。当催化剂用量为0.5%(质量分数)、醇油物质的量之比7∶1、在130℃反应90 min后,生物柴油的最高收率达到88.1%。较之酸碱两步法催化高酸值油料制备生物柴油能显著缩短反应时间、简化工艺流程、降低生产成本。     

微波辅助组合离子液体直接制备微藻生物柴油

采用小球藻、甲醇为原料,离子液体组合物作为提取催化剂,微波辅助原位一步法催化制备微藻生物柴油。考察微波功率、离子液体类型、离子液体用量、反应温度、反应时间、醇油物质的量之比等因素对酯交换率的影响,并与传统水浴加热机械搅拌法比较。结果表明:微波和离子液体对生物柴油的制备有协同促进作用,离子液体具有催化、提取与增溶的作用,能较好地消除醇油界面接触,微波的引入可强化传质传热过程,与传统加热方式水浴加热机械搅拌法相比,可缩短酯交换反应的时间,降低反应温度,减少离子液体、甲醇用量。离子液体[BMIM][HCOO]为提取剂,微藻油脂提取率最高;酸性离子液体催化效果明显高于碱性离子液体,离子液体[SO₃H-BMIM][HSO₄]为催化剂,微藻油脂转化率最高。在甲醇用量和藻粉质量比为6∶1,离子液体组合物和藻粉质量比为5∶1,[BMIM][HCOO]与[SO₃H-BMIM][HSO₄]体积比12∶1,微波功率400 W,反应温度为60℃,反应时间40 min条件下,生物柴油转化率可达93.3%。该方法将离子液体溶解提取性能、催化性能及微波的热效应相结合,将油脂的提取与油脂的酯化合二为一,能够实现微藻生物柴油的一步转化制备。     

纤维素催化热解定向调控制取不含氧烃类液体燃料

为了将生物质能高效转化为高品位不含氧的液体燃料,以纤维素为例,研究了以催化热解方式将热解产物转化为芳香烃类液体燃料的过程.实验发现,纤维素热解产生的含氧有机小分子,可以通过催化热解的形式高效转化为不含氧的芳香烃类液体.催化剂采用HZSM-5(23)、催化剂原料质量比例为5∶1、热解温度为650℃、升温速率为10000 K/s的工况为纤维素催化热解的最佳工况,单环芳烃、多环芳烃产率分别为9.90%和12.91%,总芳香烃类产率为22.81%.热解温度提升至650℃前,更高的热解温度能获得更高的芳香烃产率.继续提高热解温度,单环芳烃、多环芳烃分子间还可能进一步发生聚合反应,最终产生积碳.同时本文也提出了一种可行的纤维素催化热解中的反应途径,与本文实验结果较为匹配.     

Ga改性HZSM-5分子筛催化2-甲基呋喃和甲醇制备芳香烃

采用等体积浸渍法在HZSM-5分子筛上引入Ga₂O₃，探究Ga改性HZSM-5分子筛对2-甲基呋喃（MF）和甲醇在固定床反应器中进行偶合反应的产物分布的影响。采用XRD、HTEM、BET和NH₃-TPD对催化剂的理化性质进行表征，结果显示，Ga的负载使得HZSM-5比表面积和孔容减小，改变了HZSM-5的酸类型及酸位强度分布。偶合反应结果表明，Ga的负载能够促进MF和甲醇的转化，Ga/HZSM-5不仅可以提高芳香烃的产率，而且提高了芳香烃产物中BTX的选择性。与HZSM-5相比，0.1%Ga/HZSM-5在反应温度为500℃、MF与甲醇摩尔比为1∶2、WHSV为2 h⁻¹反应条件下，使芳香烃产率从14.6%提高到23.7%，而BTX的选择性则从55.2%提高到67.8%。     

Hydrogen production by steam reforming of dimethyl ether and CO-PrOx in a metal foam micro-reactor

A bi-function catalyst containing CuZnAlCr and HZSM-5 was used to generate hydrogen by stream reforming of dimethyl ether (SRD) in a metal foam micro-reactor and a fix-bed reactor. Dimethyl ether conversion of 99% and hydrogen yield of >95% was reached with HZSM-5/CuZnAlCr (mass ratio of 1:1) in the micro-reactor. A suitable balance between the dimethyl ether hydrolysis and methanol reforming steps requires the proper acidity and the metal sites. The CuZnAlCr/HZSM-5 properties, effect of CuZnAlCr to HZSM-5 mass ratio were investigated in the metal foam micro-reactor. Moreover, CO was removed from hydrogen-rich gas by preferential oxidation reaction (CO-PrOx) with PtFe/γ-Al₂O₃ catalyst in a similar metal foam micro-reactor follows the SRD stage. With the optimized O₂/CO ratio and reaction temperature, the CO concentration dropped to <10 ppm and hydrogen yield of ∼90% were achieved in the new-type SRD-COPrOx system. The SRD-COPrOx system provide a constant hydrogen production with CO concentration lower than 10 ppm during 20 h. The results indicate that metal foam micro-reactor has the great potential in the DME steam reforming to supply hydrogen for low-temperature fuel cells.     

Effect of cosolvent and addition of catalyst (HZSM‐5) on hydrothermal liquefaction of macroalgae

The present study aimed to evaluate the effect of the direct liquefaction of macroalgae in an autoclave reactor (50 mL) possessing water and ethanol as cosolvent. The reaction conditions such as duration, temperature, algae/solvent ratio, the composition of cosolvent (ethanol‐water) on product distribution, and bio‐oil characterization were studied. The optimum conditions such as 300°C of temperature, 45 minutes of reaction time, 75% of ethanol, and algae to solvent ratio of 4/40 g/mL supported the bio‐oil yield of 46.75% with a conversion rate of 95.5%. The composition and concentration of the compounds in the bio‐oil produced under various doses of catalyst were described using GC‐MS. The bio‐oil characterization showed that the esters were most predominant in hydrothermal liquefaction with a catalyst (HZSM‐5) compared with hydrothermal liquefaction in the absence of the catalyst.     

Microwave-assisted catalytic pyrolysis of cellulose for phenol-rich bio-oil production

The microwave-assisted catalytic pyrolysis (MACP) of cellulose was carried out using modified HZSM-5 catalysts for bio-oil production. The catalysts of Fe/HZSM-5, Ni/HZSM-5 and Fe–Ni/HZSM-5 were developed and characterized by the X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The bio-oil was characterized by the Fourier transform infrared analyzer (FTIR) and gas chromatography/mass spectrometry (GC/MS). Results showed that Fe/HZSM-5 enhanced the yields of bio-oil by 11.4% and decreased the coke by about 24% compared to HZSM-5 without modification. The saccharides in bio-oil disappeared and were totally converted into phenols and low molecular compounds with the catalysis of Fe–Ni/HZSM-5. Fe–Ni/HZSM-5 showed high selectivity of phenols (20.86%) in the bio-oil. It was a unique finding because usually phenols can only be obtained by the pyrolysis of lignin, not cellulose. The formation of phenols from MACP of cellulose was probably caused by the conversion of furans to aromatics in the pores of HZSM-5, and followed by further conversion of aromatics into phenols on the external surface of HZSM-5.     

Tungstophosphoric acid incorporated hierarchical HZSM-5 catalysts for direct synthesis of dimethyl ether

HZSM-5 zeolites are active materials in dimethyl ether (DME) production with high surface acidity. In this study, hierarchical HZSM-5 catalysts were synthesized with steam-assisted crystallization (SAC) method and then in order to increase its surface acidity, TPA was loaded into the HZSM-5 catalyst having various mass ratios (5, 10, 25%) by wet impregnation method. Synthesized catalysts were characterized by N₂ physisorption (BET analysis), X-Ray diffraction and pyridine adsorbed diffuse reflectance FTIR spectroscopy techniques. Characterization analysis of tungstophosphoric acid (TPA) impregnated catalysts indicated that hierarchical HZSM-5 possesses mesoporous structures. The average pore size distribution of TPA impregnated HZSM-5 catalysts were between 17 and 20 nm. TPA impregnation promoted Brønsted acid sites of the catalyst, which favors methanol dehydration reaction. Activity tests have been performed at reaction temperatures of 200–300 °C at 50 bar reaction pressure in the presence of admixed catalysts (physically mixed commercial HifuelR-120 and HZSM-5 based catalysts with a weight ratio of 1:1). Results revealed that the increase in the amount of heteropoly acid has enhanced DME selectivity and CO conversion. Maximum DME selectivity of 57% and CO conversion of 46% were achieved in the presence of the 25TPA@HZSM-5 catalyst at the optimum reaction temperature of 275 °C. TGA analysis result of spent catalysts presented the highest amount of coke over HZSM-5. TPA incorporation decreased coke formation due to suppression of the Lewis acid site, which is responsible for the coke formation.     

Biodiesel production by esterification of oleic acid over zeolite Y prepared from kaolin

Zeolite Y, with a Si/Al ratio 3.1, was prepared using Iraqi kaolin and tested as a catalyst in the liquid-phase esterification of oleic acid (a simulated free fatty acid frequently used as a model reaction for biodiesel production). XRD confirmed the presence of the characteristic faujasite structure of zeolite Y, and further analysis was conducted using BET adsorption, FTIR spectroscopy, XRF, DLS particle size and SEM. A range of experimental conditions were employed to study the reaction; alcohol/oleic acid molar ratio, temperature, and catalyst mass loading. The optimum conditions for the reaction were observed at 70 °C, 5 wt% catalyst loading and 6:1 ethanol to oleic acid molar ratio. The oleic acid conversion using the zeolite prepared from kaolin was 85% after 60 min, while the corresponding value for a commercial sample of HY zeolite was 76%. Our findings show that low Si/Al ratio zeolite Y is a suitable catalyst for esterification, which is in contrast to the widespread view of the unsuitability of zeolites, in general, for such applications.     

Effect of Cr promoter on performance of steam reforming of dimethyl ether in a metal foam micro-reactor

The CuZnAl/HZSM-5, CuZnAlCr/HZSM-5, CuZnAlZr/HZSM-5, CuZnAlCo/HZSM-5, and CuZnAlCe/HZSM-5 catalysts that were prepared by a co-precipitation method was used for hydrogen production from steam reforming of dimethyl ether (SRD) in a metal foam micro-reactor. These catalysts were characterized by means of XRD, TPR, SEM and BET surface areas. The results showed that promoter Cr can reduce the average pore diameter and reduction temperature of catalyst. The conversion of dimethyl ether and hydrogen yield reaches 99% and 95% respectively over CuZnAlCr/HZSM-5 catalyst under a relatively lower reaction temperature. The obtained hydrogen-riched gas is easy to purify and meet the need of polymer electrolyte membrane fuel cell. The effects of reaction temperature, space velocity and steam to DME ratio on SRD were investigated in a metal foam micro-reactor. At the conditions of T = 250 °C, the space velocity of 3884 ml/(g h), steam to DME = 5, DME conversion of >97% were obtained over the CuZnAlCr/HZSM-5 catalyst without obvious deactivation during 50 h.     

Catalytic copyrolysis of metal impregnated biomass and plastic with Ni-based HZSM-5 catalyst: Synergistic effects,kinetics and product distribution

The present work aims to investigate the thermal behavior, kinetics, thermodynamics, and product distribution during copyrolysis of transition metal salt (Ni, Co, Zn, Cu, and Fe)-added biomass and model compounds with low density polyethylene(LDPE) over a Ni-based HZSM-5 catalyst by TGA and fixed bed reactor. The interactions and reaction mechanisms during copyrolysis were evaluated. The influence of Ni-impregnated biomass (C-M) and Ni-modified HZSM-5 (Ni/HZ) on the formation of pyrolysis bio-oil from biomass and model compounds and its subsequent effect on catalytic pyrolysis vapor upgrading was discussed. The results indicated that the presence of transition metal decreased the thermal degradation temperature and thermodynamics parameters; maximum decomposition rate, and reaction complexity. Ni/HZ catalyst could further decrease the activation energy, accelerate the reaction rate and change reaction process, and the modified samples/LDPE under copyrolysis with HZSM-5 catalyst presented a more significant effect than Ni/HZ catalyst. Subsequently, the Ea of pine, cellulose and lignin changed from 24.11, 18.29, and 28.68 kJ/mol (CP@Ni/HZ) to 56.04, 69.84, and 16.21 kJ/mol (CP-Ni@HZSM-5), respectively. In addition, Ni could inhibit the depolymerization of cellulose and promoted the formation of char, coke, and lignin derived phenolics. And Ni-impregnated biomass reduced the formation of desired aromatic hydrocarbons, but result in increasing of the char and non-condensable gases. But Ni/HZ catalysts promote the conversion of biomass to target products.     

Py-GC/MS技术用于Chaetoceros sp. 硅藻的催化热解研究

采用热裂解−气质联用（Py-GC/MS）技术研究Chaetoceros sp. 硅藻粉末的催化热解特性。以HZSM-5为催化剂,考察了不同Si/Al比的HZSM-5催化剂对硅藻热解产物的影响,并考察了催化剂的使用量、热解升温速率、热解反应时间对产物的影响。结果表明：未加催化剂时,硅藻热解产物以脂肪酸为主,含量为50.05%,苯系物含量仅为0.87%;加入HZSM-5催化剂后,硅藻热解产物中脂肪酸含量减少,芳香类化合物显著增加。热解实验结果发现,Si/Al比为38、硅藻和HZSM-5比例为1∶9、热解速率10 000℃/s、热解时间为10 s时,能得到较理想的热解产品,其中苯系物产率可达57.76%,脂肪酸含量为2.63%。这说明HZSM-5（38）具有较好的脱氧和芳构化功能,有利于硅藻催化热解生成高品质的生物油产品。