Catalytic conversion of canola oil to fuels and chemical feedstocks: Part II Effect of co-feeding steam on the performance of HZSM-5 catalyst

Ca lola oil and steam were co-fed continuously to a 15.5 mm i.d. fixed-bed reactor loaded with HZSM-5 catalyst at varying process conditions. The liquid hydrocarbon product contained 60–70 wt% aromatics. The gas product was highly olefinic, while for canola oil alone it was mostly paraffinic. The C₂-C₅ olefin selectivity increased with an increase in the steam/canola oil ratio in the feed. In addition, co-feeding with steam resulted in a two-fold increase in the catalyst life. Though the exact role of steam in altering the chemistry of the reaction is not known, it is probable that the rates of olefin formation and aromatization reactions are affected by the presence of steam. The product pattern suggests the possibility of propene being the initial olefin in the reaction scheme.     

Catalytic conversion of canola oil to fuels and chemicals over various cracking catalysts

The catalytic conversion of canola oil to fuels and chemicals was studied over HZSM-5, H-mordenite, H-Y, silicalite, aluminum-pillared clay (AL-PILC) and silica-alumina catalysts in a fixed bed micro-reactor. The reactor was operated at atmospheric pressure, a temperature range of 375?500°C and weight hourly space velocity (WHSV) of 1.8 and 3.6 h^?1. An organic liquid product (OLP), light hydrocarbon gases and water were the major products. The objective was to maximize the amount of OLP and its hydrocarbon content as well as optimize the selectivity for gas phase olefinic hydrocarbons. In addition, the performance of each catalyst in terms of minimizing the coke formation was examined. Among the six catalysts, HZSM-5 gave the highest amount of OLP of 63 mass% at 1.8 WHSV and 400°C. The hydrocarbon content of this OLP product was 83.8 mass%. With the exception of silica-alumina and aluminum-pillared clay catalysts, the other catalysts gave high concentrations of aromatic hydrocarbons which ranged between 23.1–95.6 mass% of OLP. The gas products consisted mostly C₃ and C₄ hydrocarbons. Ethylene, propylene and butanes were some of the valuable hydrocarbon gases. The olefin/paraffin ratio of the gas products was highest for AL-PILC catalysts but it never exceeded unity. The results showed that it was possible to significantly alter the yield and selectivity for the different hydrocarbon products by using different catalysts or changing the catalyst functionality such as acidity, pore size and crystallinity. Reaction pathways based on these results are proposed for the conversion of canola oil     

Conversion of canola oil to various hydrocarbons over Pt/HZSM-5 bifunctional catalyst

Canola oil conversion was studied at atmospheric pressure over Pt/HZSM-5 catalyst (0.5 mass% Pt) in a fixed bed micro-reactor. The operating conditions were: temperature range of 400?500°C, weight hourly space velocity (WHSV) of 1.8 and 3.6 h^?1 and steam/oil ratio of 4. The objective was to optimize the amount of gasoline range hydrocarbons in the organic liquid product (OLP) and the selectivity towards olefins and isohydrocarbons in the gas product. The gas yields varied between 22–65 mass% and were higher in the presence of steam compared to the operation without steam. The olefin/paraffin mass ratio of C₂-C₄ hydrocarbon gases varied between 0.31–0.79. The isohydrocarbons/n-hydrocarbons ratio was higher with Pt/HZSM-5 (1.6–4.8) compared with pure HZSM-5 catalyst (0.2–1.0). The OLP yields with Pt/HZSM-5 (20–55 mass% of canola oil) were slightly lower compared to HZSM-5 (40–63 mass% of canola oil) under similar conditions. The major components of OLP were aliphatic and aromatic hydrocarbons. A scheme postulating the reaction pathways for the conversion of canola oil over Pt/HZSM-5 catalyst is also presented.     

Zn/HZSM-5分子筛催化棕榈油多产芳烃的研究

HZSM-5分子筛可用于脂肪酸酯催化转化生产芳烃、低碳烯烃等过程。未经过处理的HZSM-5分子筛芳烃产率较低,使用过渡金属改性后的HZSM-5分子筛酸性质发生了改变,能够提高芳烃的收率。以等体积浸渍法对HZSM-5分子筛进行改性,制备了不同锌含量的 Zn/HZSM-5分子筛,并进行了 XRD、XRF、XPS、NH₃-TPD、SEM、TEM、Py-IR、N₂物理吸附-脱附等多种表征,结果表明锌的引入没有改变 HZSM-5的晶体结构,锌物种能均匀分布在 HZSM-5分子筛表面及孔道。棕榈油催化转化实验结果显示Zn含量（质量分数）为3% 的 Zn/HZSM-5有最好的催化效果,芳烃在液相烃类所占比例（质量分数）为87.92%,芳烃收率（质量分数）为59.44%。     

Upgrading of tall oil to fuels and chemicals over HZSM-5 catalyst using various diluents

The upgrading of crude tall oil (CTO) to fuels and chemicals was studied at atmospheric pressure and in the temperature range 370 to 440°C in a fixed bed microreactor containing HZSM-5. The oil was co-fed with diluents such as tetralin, methanol and steam. High oil conversions of the order of 80–90 wt. % were obtained using tetralin and methanol as diluents but with steam the conversion only ranged between 36 to 70 wt. %. The maximum concentration of gasoline range aromatic hydrocarbons in the liquid product was 52 and 57 wt. % with tetralin and steam but only 39 wt. % with methanol. The amount of gas product in most of the runs was 1–4 wt.%. A reaction scheme is postulated based on the results.     

Catalytic conversion of palm oil to fuels and chemicals

The conversion of palm oil to hydrocarbons using a shape selective zeolite catalyst is reported in this work. Palm oil was passed over HZSM-5 catalyst in a fixed bed micro-reactor and the reactor was operated at atmospheric pressure, a temperature range of 360 to 420°C and weight hourly space velocity (WHSV) of 2 to 4 h^?1. The main objective was to study the effect of reaction temperature and oil space velocity on the conversion and selectivity of gasoline range hydrocarbons. The results show that 40 to 70wt% of the palm oil can be converted to aromatics and hydrocarbons in the gasoline, diesel and kerosene range, light gases, coke and water. The maximum gasoline range hydrocarbons yield of 40wt% of total product formed was obtained at 400°C and 2 h^?1 space velocity.     

废塑料化学转化制燃料的催化剂研究进展

在简要介绍和比较热裂解、催化裂解、热裂解-催化改质和催化裂解-催化改质4种废塑料化学转化制燃料基本方法的基础上,综述了近年来国内外在废塑料裂解催化剂和废塑料裂解产物改质催化剂的研究进展,重点讨论了催化剂酸性、比表面积、孔径以及负载金属离子的类型等对废塑料催化裂解和催化改质反应性能的影响,并介绍了聚烯烃（包括聚乙烯和聚丙烯）废塑料和聚苯乙烯废塑料热裂解和催化裂解的反应机理。最后对废塑料化学转化制燃料技术的研究与开发提出了一些建议,指出采用催化裂解-催化改质组合技术是未来废塑料化学转化制燃料过程的发展趋势,其今后的研究重点将是开发具有较强酸性和有利于大分子扩散与传质性能孔道结构的分子筛催化剂。     

Chemical thermodynamic study of the conversion of fossil fuels to prime chemical feedstocks with steam

Reasons for studying a purely thermodynamic approach to the problem of carbon formation in the steam reforming of oil feedstocks are outlined. The Newton-Raphson method was successfully applied to the problem of solving the complex equilibria equations. Using the concept of the feasible region of gas composition, the problems of divergence often encountered with this technique were avoided. Furthermore, the boundaries of temperature and pressure at which carbon will begin to form can be predicted for any specified feedstock and steam input. These boundaries were found to be sensitive to the steam to carbon atom ratio for a given fuel and the analysis demonstrated the temperature and pressure effect on the sensitivity of carbon formation.     

Mesoporous HZSM-5 catalysts for the conversion of waste plastics to liquid fuels

Journal of Porous Materials - Three micro-mesoporous HZSM-5 catalysts were synthesized using three different mesoporous templates and studied for the conversion of a model municipal waste plastic...     

HZSM-5催化条件下反应温度对热解油品质影响规律

在酸性分子筛HZSM-5催化条件下,以玉米秸秆粉为原料,考察了反应温度对热解油品质的影响。在自制流化床热裂解装置上,选取了5种反应温度（450℃、500℃、550℃、600℃及650℃）,进行催化热裂解实验,探究热解油含水率、pH和化学组分的变化规律。结果表明：在HZSM-5催化剂作用下,热解油含水率与pH随反应温度线性增加,酸性随着含水率的升高而减弱（pH增大）;热解油中酸类、酚类、酯类及醇类相对含量比酮类、醛类及糖类受反应温度影响更加明显;在HZSM-5催化剂与物料质量比1：10,反应温度为500℃时,热解油品质较好,腐蚀性低、稳定性高,酚类物质种类丰富、相对含量高。研究结果为HZSM-5催化条件下反应温度调控、改善热解油品质提供了一定的科学依据,有利于热解油后续高值化、环保化利用。     

纳米碳酸钙在汽车抗石击涂料中的应用

综述了纳米碳酸钙在不同体系的汽车底盘抗石击涂料中的应用,阐述了纳米碳酸钙作为新型廉价无机填料,填充于汽车抗石击涂料中,可使底盘表面具有弹性、耐水性及耐腐蚀性,更好的防护石击;也阐述了纳米碳酸钙对沥青、PVC、聚氨酯等树脂基料的改性,使涂料更具有亲水性;评价了目前应用最多的PVC抗石击涂料的不足——PVC抗石击涂料均使用了有机溶剂,在高温塑化过程中会产生大量的挥发性有机物,对环境造成了污染;指出了以聚氨酯、聚酯、丙烯酸等体系为代表的抗石击水性涂料的研发是世界当今汽车涂料发展的趋势。     

Catalytic conversion of asphaltenes to BTXN using metal-loaded modified HZSM-5

HZSM-5 zeolites with Si/Al ratios of 20, 35, 50 and 65 were prepared by the directing crystallization process of silicalite-1 seeds. The influence of Si/Al ratios on the production of benzene, toluene, xylene and naphthalene(BTXN) originated from asphaltenes catalytic pyrolysis was explored by adopting Py-GC/MS.Modified Z5-50 zeolites were prepared by various metal ions(Ni²⁺, Mo⁶⁺, Fe³⁺, and Co²⁺) with different loading rates(3%(mass), 5%(mass), 7%(mas...     

Si改性对HZSM-5催化剂MTO性能的影响

以正硅酸乙酯(TEOS)为调控剂,调节HZSM-5(SiO_2/Al_2O_3=50)的孔结构与酸性,采用XRD、BET、NH_3-TPD等表征调节前后HZSM-5催化剂的晶相、孔结构和酸性,考察了Si沉积改性对HZSM-5催化剂MTO催化活性的影响。结果表明,采用TEOS进行Si改性的方法不会改变HZSM-5的骨架结构,焙烧后SiO_2覆盖在HZSM-5的表面,调变了HZSM-5的孔径、钝化了HZSM-5的酸性,提高了其对MTO反应的催化活性。当TEOS与HZSM-5质量比为0.15时,可以达到较好的改性效果,在保持甲醇转化率为100%的前提下,低碳烯烃选择性达到了65.40%,较改性前提高了18个百分点,丙烯的选择性30.97%,提升率为58%。     

改性HZSM-5对甲醇制烯烃反应性能的影响研究

分别用非金属、碱金属、碱土金属、过渡金属以及稀土金属对HZSM-5催化剂进行改性,考察了改性催化剂对低碳烯烃的选择性影响,并选取改性效果较好的元素组合制备双金属改性催化剂,以进一步提高低碳烯烃的选择性。结果表明,双金属改性催化剂可明显提高C2=～C4=的总烯烃选择性,副产物得到了有效抑制。其中,钾-钙改性后丙烯的选择性最好,从25%提高到42%;钙-铈改性后,乙烯选择性较高,从25%提高到43%;钾-锌和钙-锌改性后,低碳烯烃选择性下降,二甲醚的选择性呈现不断上升趋势,从5%提高到60%左右。改性催化剂对反应过程的影响从一定程度上验证了本文提出的MTO反应网络。     

ZnZr/HZSM-5双功能催化剂在合成气与苯烷基化反应中的催化性能

将系列锌锆金属氧化物与HZSM-5分子筛耦合制备成双功能复合催化剂,并将其应用于合成气与苯烷基化反应。研究结果表明,ZnO是合成甲醇的主要活性组分,ZrO₂的加入能够促进ZnO分散,同时其表面具有的氧空位可促进CO的活化,二者结合方式显著影响反应活性。SEM、XPS、CO-TPD等表征结果表明,ZnO与ZrO₂相结合不仅能够提高ZnO的分散度,而且能调控氧化物表面的氧空位浓度,当二者形成固溶体时,锌在氧化锆中的分散度最大,表面氧空位浓度最高,CO吸附量最大,催化活性最高。锌锆结合方式一定时,锌含量是影响催化活性的另一重要因素,n(Zr)/n(Zn)=2的锌锆固溶体与HZSM-5以质量比1∶2耦合表现出最高的催化活性,CO和苯的转化率为34.65%和35.82%时,甲苯和二甲苯的总选择性高达85.24%。     

中油型加氢裂化催化剂工艺条件的影响

以NNY分子筛和Hβ分子筛为酸性组分,以γ-Al₂O₃为载体原料、Ni-W为金属组分、P为改性剂,采用较合适的配比利用挤条成型法和等体积饱和浸渍法制备较优的中油型加氢裂化催化剂,并针对此催化剂,在恒压15 MPa条件下,反应温度、空速和氢油体积比的变化对加氢裂化过程中馏分油转化率、产品分布、中油选择性和HDS、HDN效果的影响进行探究。结果表明,随着反应温度升高,转化率增大,产品分布向轻组分偏移,脱硫率和脱氮率增加,但中油选择性降低;随着空速增大,转化率、脱硫率和脱氮率均降低,中油选择性增大;随着氢油体积比增大,转化率、脱硫率和脱氮率先增大后趋于稳定,产品分布和中油选择性基本不变。在反应压力15 MPa、反应温度380 ℃、空速0.7 h^-1和氢油体积比1 500∶1条件下,转化率84.6%,中油选择性91.3%,生成油硫含量9.28 μg·g^-1,氮含量1.46 μg·g^-1。     

钾-钙双金属改性对HZSM-5分子筛催化甲醇制丙烯的影响

针对甲醇制丙烯反应体系,研究了不同金属、双金属改性的HZSM-5的催化性能。结果表明,钾改性提高了催化剂的稳定性和催化性能,当钾改性液的质量分数为2%时,改性效果最好,在此基础上,以2%K-HZSM-5作为不同钙负载的改性对象。结果表明,钾钙共同改性,具有较好的协同改性效果,大大提高了丙烯的选择性,有效的降低了乙烯和副产物的产率。     

Performance studies of various cracking catalysts in the conversion of canola oil to fuels and chemicals in a fluidized-bed reactor

Studies were conducted at atmospheric pressure at temperatures in the range of 400–500°C and fluidizing gas velocities in the range of 0.37–0.58 m/min (at standard temperature and pressure) to evaluate the performance of various cracking catalysts for canola oil conversion in a fluidized-bed reactor. Results show that canola oil conversions were high (in the range of 78–98 wt%) and increased with an increase in both temperature and catalyst acid site density and with a decrease in fluidizing gas velocity. The product distribution mostly consisted of hydrocarbon gases in the C₁–C₅ range, a mixture of aromatic and aliphatic hydrocarbons in the organic liquid product (OLP) and coke. The yields of C₄ hydrocarbons, aromatic hydrocarbons and C₂–C₄ olefins increased with both temperature and catalyst acid site density but decreased with an increase in fluidizing gas velocity. In contrast, the yields of aliphatic and C₅ hydrocarbons followed trends completely opposite to those of C₂–C₄ olefins and aromatic hydrocarbons. A comparison of performance of the catalysts in a fluidized-bed reactor with earlier work in a fixed-bed reactor showed that selectivities for formation of both C₅ and iso-C₄ hydrocarbons in a fluidized-bed reactor were extremely high (maximum of 68.7 and 18 wt% of the gas product) as compared to maximum selectivities of 18 and 16 wt% of the gas product, respectively, in the fixed-bed reactor. Also, selectivity for formation of gas products was higher for runs with the fluidized-bed reactor than for those with the fixed-bed reactor, whereas the selectivity for OLP was higher with the fixed-bed reactor. Furthermore, both temperature and catalyst determined whether the fractions of aromatic hydrocarbons in the OLP were higher in the fluidized-bed or fixed-bed reactor.     

Interzeolite conversion of HY to hierarchical HZSM-5 catalyst via an ionothermal route and its excellent catalytic performance in methanol-to-aromatics reaction

Journal of Porous Materials - Currently, synthesizing zeolites with specific physicochemical properties in a more environmentally benign and safe way is challenging. Herein we report a novel...     

操作条件对锡改性HZSM-5催化剂芳构化性能的影响

采用75~120℃的催化裂化轻汽油馏份为原料,在小型固定床反应器上研究了不同方法制备的锡改性HZSM-5催化剂的芳构化性能,考察了反应温度和反应压力对芳构化过程的影响。结果表明,HCl-Sn/HZSM-5催化剂的稳定性最好,最佳反应条件为:液时空速(LHSV)1.0 h-1,反应温度为550℃,反应压力为0.3 MPa,在最佳反应条件下,芳烃总含量为92.88%,烯烃和烷烃转化率分别为93.93%和89.97%。