焦化苯中噻吩类硫化物脱除技术研究进展

我国焦化苯粗品中噻吩含量普遍偏高,脱除焦化苯中的噻吩类硫化物,可提高焦化苯的质量,有利于其进一步的深加工利用。目前,焦化苯中噻吩类硫化物脱除技术主要有萃取精馏法、选择吸附法、选择氧化法、催化加氢法、酸洗精制法等;另外,Friedel-Crafts反应脱硫法和氯甲基化脱硫法也可将焦化苯中纯苯与噻吩类硫化物分离。选择吸附法脱硫技术具备硫酸酸洗精制法操作简单和催化加氢法脱硫精度高、以及萃取精馏法可回收噻吩的优点,具有较大的工业化推广应用价值,提高吸附剂吸附容量以及吸附剂的稳定性将是选择吸附法今后研究的重点。近年来,离子液体已用于催化裂化汽油中硫化物的脱除,这对将来采用离子液体脱除焦化苯中噻吩的技术研究具有重要的借鉴意义。     

噻吩、苯和正辛烷在Y型分子筛上的选择性吸附

采用重量法测定了温度为373 K、335 K和302 K时,噻吩、苯和正辛烷在NaY分子筛及CeY分子筛上的吸附等温线。结果表明,各温度下,噻吩在NaY分子筛和CeY分子筛上的饱和吸附量基本相同,并且其吸附量相对于苯和正辛烷较大。苯和正辛烷在CeY分子筛上的饱和吸附量很小,且较NaY分子筛上的吸附量明显的下降。CeY分子筛对噻吩有更高的选择性。     

焦化苯中噻吩类硫化物脱除的研究

焦化苯中噻吩类硫化物的脱除对苯的进一步加工利用非常重要.根据苯和噻吩物理化学性质的差异,可选用的脱除方法有硫酸精制、催化加氢、萃取精馏、冷冻结晶、选择吸附等.本文对这几种方法进行分析比较后认为,硫酸精制法设备腐蚀严重、环境污染大;催化加氢法耗费氧气、操作费用高;萃取精馏法能耗高、脱硫效果差;冷冻结晶法易形成混晶.与此相比,选择吸附脱硫(SARS)具有设备腐蚀小、环境污染少、操作费用低、不耗费氢气、能回收噻吩等优点,是一种很有发展潜力的方法.     

分子筛催化噻吩类硫化物与烯烃烷基化脱硫研究

采用GC—FPD,GC—MS,NH3-TPD及BET等手段,以噻吩,2-甲基噻吩,3-甲基噻吩,2-乙基噻吩及2,5-二甲基噻吩为模型硫合物,异丁烯为烷基化剂,对HZSM-5,Hβ,HM,HY,HMCM-41等分子筛为催化剂催化噻吩类硫化物与异丁烯的烷基化反应进行了研究,并比较不同分子筛的酸强度分布及孔径大小对噻吩类硫化物与异丁烯的烷基化反应性能的影响。结果表明,Hβ,HM,HY,HMCM-41催化剂催化噻吩与异丁烯的烷基化反应在温和的反应条件下(如80℃,常压)即可达到较高的转化率,分子筛催化剂的孔径大小是影响催化括性的关键因素。     

金瑞特开发高纯度焦化无硫苯新技术

<正>近日,由河北金瑞特化工有限公司承担的科研项目—高纯度焦化无硫苯新技术开发与应用,完成了市科技计划项目任务,通过了市科技局组织的专家验收。项目的研发,是以粗苯为原料,采用氧化法工艺,在催化条件下,去除原料中的硫化物、不饱和化合物及氮化物,反应液经中和、萃取蒸馏、吸附后得产品,并实现生产过程中催化     

粗苯加氢工艺催化剂的再生

石家庄焦化集团引进德国K·K公司的焦化粗苯加氢精制技术,以焦化粗苯为原料,通过2段控制加氢、莫菲兰萃取蒸馏和精馏生产高纯苯、甲苯等多种产品。该装置采用NiMo、CoMo催化剂,加氢温度和操作压力低,操作稳定易掌握,加氢反应后的产品总硫含量小于2.0mg/kg,产品符合德国、美国和日本质量标准。     

固体复合酸催化FCC汽油中噻吩类硫化物烷基化反应动力学

以固体复合酸为催化剂,对汽油中的主要硫化物噻吩(T)、2-甲基噻吩(2-MT)、3-甲基噻吩(3-MT)、2,4-二甲基噻吩(2,4-DMT)烷基化硫转移反应动力学进行研究。结果表明:4种噻吩类硫化物转化率均随反应温度的升高而增大,适宜的动力学考察温度为403.15~433.15 K,当反应温度为433.15 K时,4种硫化物的转化率均达最大,大小依次为2-MT3-MTT2,4-DMT。4种硫化物的烷基化反应动力学方程均符合一级反应速率方程。T,2-MT,3-MT和2,4-DMT的烷基化反应活化能分别为27.92,25.98,45.25和27.29 kJ/mol,指前因子分别为4.427×103,5.316×103,9.98×105和3.91×103h-1。     

焦化粗苯加氢精制催化剂的研制

采用分步浸渍法制备了NiMo/Ti-Al预加氢催化剂、CoMo/Ti-Al主加氢催化剂,在微型固定床反应器上考察了加氢活性、脱硫活性与催化剂组成的关系.筛选出的2Ni8Mo/Ti-Al、2Co8Mo/Ti-Al催化剂在实验条件下能将焦化粗苯中的噻吩硫脱除,三苯的收率可达到99%以上.     

关于焦化粗苯加氢反应条件的分析

本文主要论述了焦化粗苯加氢精制的工艺方法和对焦化粗苯加氢的主要反应条件的控制,并简单介绍国内焦化粗苯加氢工艺的应用。通过分析加氢反应的温度、压力、空速选择、原料比等不同条件下的加氢反应,来观察各影响因素对加氢反应的影响。研究表明,在焦化粗苯加氢反应中,适当降低反应的温度、提高反应系统的压力、合适的空速、适当提高氢气的分压都有助于焦化粗苯反应的进行,同时有助于保持催化剂的活性,延长催化剂的使用寿命。     

硫化物对裂解汽油一段加氢用Pd/Al_2O_3催化剂性能的影响

采用固定床反应器考察了多种硫化物(二硫化碳、二甲基二硫与噻吩)对裂解汽油一段加氢用Pd/Al2O3催化剂加氢性能的影响。在相同的工艺条件下,硫化物的毒性顺序为:二硫化碳二甲基二硫噻吩。CS2对催化剂加氢性能的影响最为明显,原料油中CS2质量分数达到6μg/g后,催化剂就迅速发生中毒,产品双烯值增高。催化剂失活的原因是CS2主要以物理吸附的方式占据催化加氢活性中心,导致催化剂对共轭烯烃与氢气失去吸附活性。     

焦化粗苯催化加氢精制纯苯的研究与开发

焦化粗苯低温(<390℃)、低压(<3.5MPa)加氢精制过程与溶剂萃取技术相结合,可获得高纯度的苯、甲苯和二甲苯,芳烃收率比酸洗法提高8%～10%,并解决了环境污染问题。立足国内技术建设粗苯加氢精制工厂是可行的。     

Mechanism transformation of cyclohexene-thiophene competitive adsorption in FAU zeolite

Competition of hydrocarbon compounds with sulfides in gasoline has caused a not very high selectivity of sulfides in adsorption desulfurization so far, resulting in a reduction of catalyst lifetime as well as more sulfur oxide emissions. Tostudy the whole competitive process changing with the increase of the loading, the dynamic competition adsorption mechanism of cyclohexene and thiophene in siliceous faujasite (FAU) zeolite was analyzed by the Monte Carlo simulation. The results showed that with the increase of the loading, thiophene and cyclohexene had different performances before and after the inflection point of 40 molecule/UC. The adsorbates weredistributed ideally at optimal sites during the stage that occurredbefore the inflection point, which is called the "optimal-displacement adsorption" stage. When approachingthe inflection point, the competition became apparent and the displacement appeared accordingly, some thiophene molecules at S sites (refers to the sites inside the supercages) were displaced by cyclohexene. After the inflection point, the concentration of adsorbates at W sites (refers to the 12-membered ring connecting the supercages) was significantly reduced, whereas the adsorbates at S sites got more concentrated. The stage some cyclohexene molecules displaced by thiophene and inserted into the center of the supercage can be named as the "insertion-displacement adsorption" stage, and both the adsorption behavior and the competitive relationship became localized when the adsorption amount became saturated. This shift in the competitive adsorption mechanism was due to the sharp increase of interaction energy between the adsorbates. Besides, the increase in temperature and ratio of Si/Al will allow the adsorbates, especially thiophene molecules to occupy more adsorption sites, and it is beneficial to improve the desulfurization selectivity.     

The effect of mass transfer on the catalytic combustion of benzene and methane over palladium catalysts supported on porous materials

Catalytic combustion of benzene and methane over palladium catalysts supported on FAU and MOR zeolites and MCM-41 and KIT-1 mesoporous materials were studied to illustrate the effect of pore size and shape of supports on their catalytic activities. The palladium catalysts supported on mesoporous materials showed high activity and a steep increase in the conversion of benzene with rising temperature. The low activity of palladium catalysts supported on FAU zeolite was ascribed to mass transfer limitation. However, conversion profiles of methane on palladium catalysts were similar, although their supports were different as zeolites and mesoporous materials. The catalytic behavior of palladium catalysts in the combustion of benzene and methane was explained by the diffusion properties of fuels in the pores of zeolites and mesoporous materials.     

焦化苯中噻吩在酸性沸石催化剂上的催化裂解性能

研究了焦化苯中噻吩在酸性沸石催化剂上的催化裂解性能. 结果表明：噻吩在HZSM-5沸石催化剂的作用下被分解生成硫化氢气体逸出,进而达到脱硫的目的. 通过对不同温度和压力下的催化脱硫性能进行考察,认为HZSM-5沸石催化剂对脱除苯中噻吩具有较高的活性及较好的活性稳定性,且温度、压力是影响催化剂活性和稳定性的重要因素. 以含270 mg/L噻吩的焦化苯为原料,在反应温度为320~380℃、反应压力为3.5~6.0 MPa、质量空速为4~12 h-1的条件下,能彻底脱除其中的噻吩.     

不同模板剂作用下CHA型沸石的制备研究

CHA型沸石在化学化工行业中具有优异的催化、吸附以及膜分离性能，但是在其合成过程中极易出现MER型杂晶，因此合成纯相CHA型沸石具有一定的难度。为了制备高结晶度的纯相CHA型沸石，在FAU型沸石的配方基础上详细考察了无K⁺以及含K⁺合成体系中四甲基氢氧化铵(TMAOH)与四甲基氟化铵(TMAF)两种模板剂对产物的影响，并深入研究了FAU、MER、CHA型沸石的转晶行为，从而寻找出纯相CHA型沸石的合成途径。结果表明，相比TMAOH,TMAF模板剂更利于合成出纯相的CHA型沸石，同时在含K⁺的合成体系中产物的结晶度更高、晶型更为完整。     

Molecular simulation of hydrogen adsorption in organic zeolite

The adsorption of molecular hydrogen on model zeolites has been simulated employing Grand Canonical Monte Carlo (GCMC) procedure. The effects of cation type, available volume, surface area, temperature, pressure and pre-adsorbed organics such as benzene on the hydrogen uptake are analyzed. The hydrogen adsorption can be affected mainly by the available volume and surface area per g-zeolite at the same temperature and pressure. Increase of temperature results in the decrease of sorption intensity and capacity. The adsorption capacity correlates well with the pressure with high linearity at room temperature. Adsorption is lowered by the pre-adsorbed benzene molecule. The orientation and the number of benzene molecule in zeolite affect the adsorption capacity. The organic zeolite with larger available volume shows larger adsorption capacity.     

活化及反应条件对镍系苯加氢催化剂性能的影响

采用二次浸渍法制备镍催化剂,通过改变工艺条件进行单因素试验,考察不同工艺条件对镍系苯加氢催化剂性能的影响。结果表明,在纯氢环境下,程序升温可以使催化剂充分活化,在反应压力（0.6~0.8） MPa、液苯空速（0.8~1.0） h^-1、反应入口温度约140 ℃和氢与苯物质的量比为6.0~8.0的条件下,催化剂具有良好的性能。     

Metal-support effects in Pt/L-zeolite catalysts

A series of Pt/L-zeolites with different cations (varying acidity) were prepared and characterized by H₂ and CO chemisorption and competitive toluene/benzene hydrogenation. The ratio of adsorption equilibrium constants for toluene/benzene was extracted from rates of hydrogenation. The variation of this ratio across a series of alkaline-earth exchanged Pt/L-zeolites indicates that there is a varying support interaction with Pt clusters in the zeolite and suggests that the clusters interact electronically with the support.     

Extra-framework charge and impurities effect,Grand Canonical Monte Carlo and volumetric measurements of CO2/CH4/N2 uptake on NaX molecular sieve

In this work, Monte Carlo simulation of CO₂, N₂, and CH₄ adsorption on zeolite 13X is carried out in grand canonical ensemble. FAU framework was used to reproduce the structure of zeolite 13X. Universal force field was used to calculate the interactions between adsorbates and 13X. Metropolis method was used for calculating adsorption isotherm. Volumetric measurements were carried out to confirm the simulation results. The simulation results using Universal force field showed good agreement with experimental results. Highest CO₂ uptake for this zeolite was found as 5.67 mol/kg from GCMC. Isosteric heat of adsorption was investigated to find the heat released during adsorption of each gas. The simulation result of isosteric heat of adsorption for CO₂, N₂, and CH₄ was utmost 17.00, 4.37, and 6.14 kcal/mole, respectively. Radial distribution graphs were used to find affinity of constituents of zeolite for CO₂. Henry’s constant evaluation was also performed at low pressure to find the selectivity of the structure. Henry’s constant of CO₂ in an equimolar mixture of N₂ and CH₄ was calculated 3.49 and 1.49 mol/kg.kPa, respectively. Finally, simulation results were fitted to Toth and dual-site Langmuir isotherms to find the best fit that belongs to dual-site Langmuir.