EFFECTS OF HEATING RATE AND PARTICLE SIZE ON THE PRODUCTS YIELDS FROM RAPID PYROLYSIS OF BEECH-WOOD

Effects of pyrolysis temperature (300-1000 ^°C), heating rates (100, 500, 1000, and 10,000 ^°C/s), and particle sizes (53-63,104-120,177-270, and 270-500 urn) on the yields and formation rates of tar, light oils, total gases, and char from pyrolysis of beech-wood under 1 atm helium pressure were studied. Wood particles were pyrolyzed in strips of stainless steel wire mesh in a captive sample apparatus; and yields of products were measured in weight percent of original wood as a function of temperature for different heating rates and particle sizes. The overall weight loss achieved from pyrolysis of this wood was about 90%. The total yields of tar and light oils from pyrolysis of this wood accounted for up to 80% of the original wood above 400 ^°C. Due to the post-pyrolysis reactions of tar and light oils, the tar and light oils yields go through a maximum with pyrolysis temperature for all particle sizes and most heating rates studied here. As particle size increases from 53-63 μm to 270-500 μm the maximum tar yield decreases from 53% to about 38%. The maximum tar yield also decreases with increasing the heating rate from 70% at 100 ^°C/s to 48% at 10,000 ^°C/s heating rate. Theses results indicate that as the intra-panicle post-pyrolysis cracking reactions of tar increases at higher heating rates and with larger particles the tar yield decreases. Tar was also analyzed with GPC for the effects of above pyrolysis parameters on the tar molecular weight. The tar average molecular weight. remains relatively constant (M     

Poly-functional Catalyst Development for Benzene Production from Alkyl-aromatic Mixture via Hydrodealkylation

Development of a poly-functional catalyst that has higher hydrodealkylation activity based on 15% Cr/γ- Al₂ O₃ was researched for benzene production from an alkyl-aromatic mixture via hydrodealkylation. For this goal, the effects of the promoters like Fe, Co, or Ni and their concentrations on the activity of a Cr/Al₂ O₃ catalyst were investigated. Toluene + n-heptane + tetrahydrotiophene (89:10:1 w%) model mixture, which has the same content as industrial aromatics, was used as feedstock. The activities of catalysis in reactions of hydrodealkylation, hydrocracking, and hydrogenolize with respect to conversions of toluene, heptane, and tetrahydrotiophene were tested, respectively. As to the obtained results, the catalyst including 5% Fe has a higher hydrodealkylation activity, compared to the catalyst including Co, and especially to the alumocrom catalyst not including a promoter, while it has a lower coke formation and reduced activity to the catalyst including Ni.     

催化剂粒径分布对催化裂化产物选择性的影响

以青岛加氢蜡油为原料,在小型固定流化床装置上通过改变剂油比,研究了催化裂化催化剂粒径分布对裂化产品选择性的影响。研究结果表明,随着剂油比的增加,四种不同粒径分布的催化剂的转化率逐渐增加;粒径在40~80 μm的催化剂具有较优的干气、焦炭和汽油选择性;粒径小于40 μm的催化剂尽管微反活性最高,但重油转化能力最差;随着转化率的增加,汽油中正构烷烃和芳香烃的含量逐渐增加,烯烃和环烷烃的含量逐渐减少。     

PARTICLE SIZE,SOLVENT, OXYGEN,TEMPERATURE AND PRESSURE EFFECTS ON THE CONTENTS OF INSOLUBLE FRACTIONS FROM SOLID VACUUM RESIDUA

ABSTRACT

n-Heptane insoluble contents were determined for an extraheavy-oil vacuum residue, one petroleum and one coal pitch as a function of particle size. This variable was found to affect the yields of insoluble material, aspect which was also observed during extractions carried out with aromatic and halogenated solvents. The precision of results was observed to be independent on the operators. A study was carried out to determine the effect of sample drying time on fraction yields. It was found that maltene fractions were strongly dependent on this variable, whereas asphaltene fractions were totally independent

Predissolution in aromatic solvents proved worthless from the repeatability point of view. However, predissolution of the oil residue in CH₂Cl₂ followed by filtration and asphaltene precipitation with simultaneous solvent removal, was deemed to be a suitable technique to remove mineral matter and isolate asphaltenes in a single step

Sample oxidation during asphaltene precipitation and isolation was detected by gravimetric and spectroscopic techniques. This fact is very important since common precipitation techniques do not address this issue

Preliminary accelerated extraction experiments carried out with pitch samples at high temperature and pressure, revealed that this approach can be a very interesting research tool to investigate solubility properties.     

PARTICLE SIZE, SOLVENT, OXYGEN, TEMPERATURE AND PRESSURE EFFECTS ON THE CONTENTS OF INSOLUBLE FRACTIONS FROM SOLID VACUUM RESIDUA

n-Heptane insoluble contents were determined for an extraheavy-oil vacuum residue, one petroleum and one coal pitch as a function of particle size. This variable was found to affect the yields of insoluble material, aspect which was also observed during extractions carried out with aromatic and halogenated solvents. The precision of results was observed to be independent on the operators. A study was carried out to determine the effect of sample drying time on fraction yields. It was found that maltene fractions were strongly dependent on this variable, whereas asphaltene fractions were totally independent

Predissolution in aromatic solvents proved worthless from the repeatability point of view. However, predissolution of the oil residue in CH₂Cl₂ followed by filtration and asphaltene precipitation with simultaneous solvent removal, was deemed to be a suitable technique to remove mineral matter and isolate asphaltenes in a single step

Sample oxidation during asphaltene precipitation and isolation was detected by gravimetric and spectroscopic techniques. This fact is very important since common precipitation techniques do not address this issue

Preliminary accelerated extraction experiments carried out with pitch samples at high temperature and pressure, revealed that this approach can be a very interesting research tool to investigate solubility properties.     

小晶粒Y型分子筛的催化性能

考察了ＮａＹ分子筛晶粒变小对其稳定性能及催化剂活性的影响。ＮａＹ分子筛晶粒适当变小,可提高催化剂活性,但当ＮａＹ分子筛晶粒小于４００ｎｍ时,则会降低催化剂活性。选定合适的小晶粒（５４３ｎｍ）ＮａＹ分子筛成催化剂,经固定流化床评价表明,可使催化剂的转化率和轻质油收率分别提高１．７４个百分点和２．２７个百分点,总液体收率增加１．９４个百分点,焦炭产率略降低。     

助剂钾,钙对铁基二乙苯脱氢催化剂性能的影响

通过对铁基催化剂的活性评价,ＸＲＤ,ＴＰＲ,ＴＰＤ,积炭和比表面积的测定,发现助剂钾对催化剂的选择性影响显著,且有较强的抗积炭能力,且剂钙对催化剂的转化率,选择性影响显著,对催化剂的颗粒大小也有一定的影响。     

LOW TEMPERATURE PYROLYSIS OF BLACK LIQUOR AND POLYMERIZATION OF PRODUCTS IN ALKALI AQUEOUS MEDIUM

ABSTRACT

Atmospheric pressure pyrolysis for the production of liquids and gases from black liquor and its calcium salts and acidic precipitate have been carried out in a little stainless steel tube. Yields, sum of liquid and gas products, from black liquor and its calcium salts and acidic precipitate were 44.7 %, 52.0 % and 59.1 % of dry basis respectively. The precipitates obtained from black liquor by acidifying with hydrochloric acid and passing carbon dioxide have been polymerized in aqueous acetone containing formaldehyde and ammonia, and converted a polymeric resin.     

FCC催化剂的球形度及粒度分布控制方法

通过研究FCC催化剂喷雾成形过程中胶体液滴的干燥原理,分析了异形颗粒和粒径小于40μm的催化剂细颗粒产生的原因,设计了一种新结构雾化喷枪来控制异形颗粒产生、减少细粉生成.该新型喷枪可将冷空气引入到喷雾干燥塔内的料液锥状雾化层(雾锥)周围,隔断浆料雾化液滴与入塔高温气氛的直接接触,为雾化液滴建立了一个相对缓和的初始干燥环...     

助剂对悬浮床加氢水溶性催化剂分散性及生焦形态的影响

 采用BT-9300H激光粒度仪和SEM手段,考察了助剂SAC和SA对水溶性催化剂分散度,以及对釜反应生焦率和液相焦形貌的影响。结果表明,加入助剂后,催化剂的颗粒粒径明显减小,比表面积显著增大;SA对水溶性催化剂的分散作用要优于SAC。随着催化剂分散效果的增加,加氢裂化反应生焦率明显降低,液相焦颗粒变小,形貌趋于规整球体,表面疏松。水溶性催化剂分散度的大小是影响加氢裂化反映生焦率和生焦形貌的重要因素。     

催化裂化对炼油厂产品结构和产品质量的影响

催化裂化装置是炼油厂最重要的二次加工装置之一。催化裂化装置对炼油厂的产品产率、柴／汽比、汽油和柴油产品质量有重要影响。催化裂化装置还生产大量可以用于生产优质汽油组分的气体原料。     

基于催化剂粒度分布分析催化裂化装置催化剂跑损的原因

针对某催化裂化装置出现催化剂跑损故障，现场对三级旋风分离器入口进行采样，通过对跑损催化剂进行颗粒粒度分布和扫描电镜分析，探讨催化剂跑损的原因。结果表明，跑损催化剂的粒度分布曲线呈现多峰分布，其中峰值对应的粒径分别为0.8，9，30 μm。造成这种现象的原因，一方面是由于跑损催化剂中存在较严重的摩擦磨损颗粒和冲击破碎颗粒，形成了前2个较小粒径的峰值；另一方面则是由于旋风分离器的分离效率下降，使得跑损催化剂的中位粒径偏高形成了较大粒径的峰值。     

轮古稠油与煤焦油混合原料悬浮床加氢裂化研究

采用高压釜对轮古稠油和某煤焦油的混合油进行各种类型的反应研究，考察了反应条件以及催化剂浓度、稠油与煤焦油配比、供氢剂和蜡油循环对产物分布的影响。结果表明：在氢气和分散性催化剂存在下的悬浮床加氢裂化反应较之热裂化及临氢裂化反应有效地抑制了生焦及气体产率，增加了中间馏分油收率。较适宜的反应条件为：温度430℃、时间60 min、压力7.0 MPa；催化剂含量150 μg/g；稠油与煤焦油配比3:1。从生焦指数来看，镍催化剂的催化加氢性能优于铁催化剂。添加供氢剂以及蜡油循环均可抑制进料的裂化反应和生焦量，最大限度地提高反应转化率。     

渣油亚组分及其形成的胶粒颗粒尺寸的研究

 根据球形分子模型，采用特性粘度法和密度法计算了渣油亚组分(沥青质、胶质、芳香分)分子的颗粒直径；构筑了渣油中沥青质胶粒(胶团)模型，并据此计算了沥青质胶团尺寸。结果表明，采用特性粘度法，溶剂胶党性对测定沥青质大分子直径有影响，以甲基萘和苯为溶剂测定选择性粘度，关联出的沥青质分子直径分别为3.52~4.34nm和3.93~4.96nm。采用密度法计算得到的沥青质分子颗粒直径为2.39~2.79nm。大分子缔合作用对测定分子颗粒尺寸有影响。采用两种方法计算胶质、芳香分小分子颗粒直径均不受影响，分别约为1.60nm和1.25nm。渣油亚组分构成的胶团颗粒随着加氢处理深度的增加呈变小的趋势，73.3%质量分数的沥青质大分子转化成小分子。     

重油催化热裂解工艺污染铁对催化剂性能的影响与对策

针对重油催化热裂解工艺装置生产过程中出现的油浆品质恶化,造成分馏塔结焦、油品不合格、主要产品双烯烃收率偏低及油浆系统堵塞影响长周期稳定运行等问题,分析了实际运行数据,并对催化剂进行NH3-TPD和BET表征,结合对反应机理的认识,认为原料油中铁含量超标是引起上述问题的主要原因,从而提出了大量置换平衡剂和原料脱铁的应对措施。     

晶种对合成小晶粒SAPO-34分子筛的影响

以较廉价的三乙胺为模板剂,考察晶种的种类、添加环境、添加量及晶粒大小对其辅助合成SAPO-34分子筛的影响,并对晶种诱导机理进行探究。结果表明：含SAPO-5杂晶的晶种会诱导体系产生相同AFI结构的SAPO-5分子筛,但采用磷酸预处理20 h后,可制备出纯净的SAPO-34分子筛;在辅助合成中,晶种硅铝比对合成产品的收率和粒径影响明显,无论添加在酸性还是弱碱性的晶化液中,高投料硅铝比下制备的晶种均更有利于提高产品收率、降低产品平均粒径,其中酸性体系对晶种的部分刻蚀作用可提供更多表面,使晶种的诱导效应更强;在晶种添加量(占晶化液的质量分数)为0～0.5%时,随着高硅铝比晶种添加量的增大,产品收率提高,D(50)降低,且变化尤为明显,当高硅铝比晶种添加量大于1%后,晶种添加量对产品收率和D(50)的影响趋于平缓。此外,晶种辅助合成的小晶粒产品可继续用作晶种起诱导作用,且以之合成产品的收率、平均粒径、元素组成、形貌、孔结构与采用初始大颗粒晶种辅助合成的产品相近,为稳定、连续合成粒径可控的小晶粒分子筛奠定了基础。     

影响分子筛催化剂强度因素的探讨

本文介绍了制备催化剂时，在挤条成型过程中各因素对分子筛加氢裂化剂强度的影响。试验结果表明：催化剂强度随挤条时的干胶粉粒度的减小而增大；物料中水粉比过高或过低都会使分子筛催化剂的强度下降；采用田菁粉和多元羧酸的复合剂是秤高强度分子筛加氢裂化催化剂理相怕助挤剂。采用适宜条件制备的分子筛加氢裂化催化剂，经小型加氢装置评价，结果证明，该催化剂不但具有较高的强度，而且具有非常好的活性稳定性。     

MWW分子筛结构及其催化苯/乙烯烷基化反应性能的研究

对自制的MWW分子筛催化剂与国外催化剂进行了结构和催化性能的比较。通过XRD,SEM,FT-IR,29Si MAS NMR,PSD,BET等表征,发现MWW分子筛为典型的MCM-22分子筛,具有平均直径约4 m的薄饼状形貌。与国外WBZ-1催化剂相比,MWW分子筛的比表面积和B酸/L酸中心之比略高,而骨架Si/Al比和机械强度略低。通过苯/低含量乙烯烷基化制乙苯反应性能的研究,发现MWW分子筛催化剂比国外WBZ-1催化剂表现出更好的催化性能,具有更高的乙烯转化率和乙苯选择性以及更好的催化稳定性。在反应温度230 oC、反应压力2.5 MPa、苯体积空速5 h-1、苯/乙烯摩尔比4.5的条件下,MWW分子筛催化剂上乙烯转化率平均为97.1%,乙苯选择性平均为95.3%,乙基化选择性平均为99.5%,并且在反应运行1 000 h以上时仍能维持良好的催化反应性能。     

延迟焦化石油焦热重分析及热解动力学

对延迟焦在CO2和Ar两种气氛下,从室温至1 000 ℃进行热重分析,探讨其热解机理。研究表明, 延迟焦热解过程首先经历50~100 ℃的脱水阶段,较明显的失重从400 ℃开始,在620~640 ℃失重速率达到峰值,800 ℃之后快速失重,热失重速率不断增加。以三级化学反应模型模拟热解过程,在433~904 ℃的热解温度范围内,CO2气氛下的平均活化能为29.70~44.81 kJ/mol,Ar气氛下的平均活化能为57.68~69.44 kJ/mol。     

高密度聚乙烯热解生成聚乙烯蜡及产品的性质研究

采用高密度聚乙烯热解制备聚乙烯蜡。结果表明,溶剂选用A：B为3：2时效果最好。经过正交实验发现,影响转化率的因素由主到次依次为：温度,时间,剂料比。最佳反应条件为：温度320 ℃,时间3 h,剂料比1：1。最佳条件下,产品相对分子质量在2 000左右,熔程为118 ~123 ℃。