The Deactivation Factor of a ZnNi/HZSM-5 Catalyst During Aromatization

The effect of Si/Al ratio and aluminum content of the catalysts of ZnNi/HZSM-5 for aromatization is investigated in this paper. In the experiment, acid content, acidity, metal phase, and pore structure are measured using XRD, ASAP2400, and TG. From the relation of deposited carbon and acid content, we know that carbon deposition is an important reason for deactivation of catalyst, because the high-molecular-weight and high-boiling-point deposited carbon can clog the pores and cover the acid centers. The loss of zinc is another reason for deactivation. Ni was selected to be the second modifying metal to make up the loss of zinc and was confirmed to have a better result. Through this research, we find the reason for short life and bad stability for the catalyst so that we can produce high-quality catalyst.     

柴油超深度加氢脱硫Ni-Mo-W/Al2O3催化剂的失活与积炭类型的关系

The deactivation of Ni-Mo-W/Al2O3 catalyst in ultra-low-sulfur diesel production was investigated on a pilot plant. The reasons of catalyst deactivation were analyzed by the method of element analysis, BET and TG-MS. The results showed that the catalyst deactivation rate was obvious at the beginning of running, and then gradually reached a steady state after 448 h. In initial period the catalyst deactivation reason may mainly due to the formation of the carbon deposit. The carbon deposit blocked catalyst channel and the accessibility of active center decreased. The TG-MS analysis identified three types of carbon species deposited on the catalysts, the low temperature carbon deposit with high H/C atomic ratio, the medium temperature carbon deposit and the high temperature carbon with low H/C atomic ratio. The amounts of high temperature carbon deposit on catalyst determined the overall activity and, therefore the high temperature carbon was a major contributor to the deactivation of Ni-Mo-W catalyst.     

非均匀分布Pd/Al2O3催化剂活性组分Pd的迁移及其对加氢性能的影响

 研究了具有壳层结构的负载型Pd/Al₂O₃催化剂在裂解汽油选择性加氢过程中活性组分Pd的迁移现象.测定了生产装置所用新鲜催化剂和再生催化剂的比表面积、孔容和其中活性组分Pd含量,采用TEM和SEM-EDS方法表征了Pd的分散性.结果表明, 在裂解汽油选择性加氢的工艺过程中, 具有壳层结构的负载型Pd/Al₂O₃催化剂的永久性失活和选择性改变的主要原因之一是活性组分Pd的迁移. Pd迁移的基本原因是其在催化剂颗粒中的不均匀分布, 助金属组分可以限制Pd的迁移, 从而改善催化剂的性能.     

An Investigation of the Deactivation Behavior of Industrial Mo/Al2O3 and Ni-Mo/Al2O3 Catalysts in Hydrotreating Kuwait Atmospheric Residue

Abstract

The catalyst system for fixed-bed residue hydrotreating processes usually consists of different types of catalysts designed to promote hydrodemetallation (HDM), hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions to desired levels. Overall catalyst life is determined by the performance of the individual catalysts in the different reactors. Therefore, information about the activity, stability, selectivity, and deactivation behavior of the individual catalyst is highly desirable to design improved catalysts that can prolong catalyst life, increase stream efficiency, and improve process economics. In the present work, residue hydrotreating experiments were conducted on two types of industrial hydrotreating catalysts, namely Mo/Al₂O₃ and Ni-Mo/Al₂O₃, that have been used as HDM and HDS catalysts, respectively, in an industrial ARDS process. The primary objective of the study was to compare the deactivation behavior of both types of catalyst. The characterization of the used catalysts by elemental analysis, surface area, pore volume, and pore size measurements along with TPO-MS, ¹³C NMR, and electron microprobe analysis showed significant differences in the nature of the coke and metal deposits on the two types of catalysts. The role of initial coking, the relative importance of the coke, and metal depositions on the deactivation of the two types of catalyst are discussed.     

TH系列贵金属CO_2脱氢催化剂的应用与失活原因分析

介绍了华烁科技股份有限公司气体净化事业部开发的TH系列脱氢催化剂分别在以渣油、天然气和煤为原料的尿素厂CO2原料气脱氢中的应用情况;重点分析了TH系列脱氢催化剂失活原因。分析结果认为,硫中毒仍然是导致脱氢催化剂失活的主要原因,并提出了具体的解决办法。     

Correlation of Deactivation of Ni-Mo-W/Al_2O_3 during Ultra-Low-Sulfur Diesel Production with Surface Carbon Species

The deactivation of a Ni-Mo-W/Al_2O_3 catalyst during ultra-low-sulfur diesel production was investigated in a pilot plant. The reasons of catalyst deactivation were analyzed by the methods of elemental analysis, BET and TG-MS. The results showed that the catalyst deactivation rate was notable at the beginning of run, and then gradually reached a steady state after 448 h. In the initial period the catalyst deactivation may mainly be caused by the formation of the carbon deposits. The carbon deposits blocked the catalyst pores and the accessibility of active center decreased. The TG-MS analysis identified three types of carbon species deposited on the catalysts, viz.: the low temperature carbon deposit with high H/C atomic ratio, the medium temperature carbon deposit, and the high temperature carbon with low H/C atomic ratio. The amount of high temperature carbon deposits on the catalyst determined the overall activity and, therefore the high temperature carbon was a major contributor to the deactivation of Ni-Mo-W catalyst.     

Hβ-Al2O3烷基化催化剂的失活与再生

采用水热合成晶化法制备了纳米级Hβ分子筛和机械混捏法制备了纳米复合Hβ-Al2O3分子筛烷基化催化剂,采用TG,BET,NH3-TPD, Py-IR等技术对失活的Hβ-Al2O3分子筛催化剂的失活原因进行了分析,考察了失活催化剂的空气再生条件并研究了失活催化剂的烧炭再生动力学。结果表明:积炭堵塞催化剂微孔孔道和覆盖大部分中等强度的L酸中心是催化剂失活的主要原因; 失活催化剂的适宜再生条件为温度450 ℃,空气流量50 mL/min;失活催化剂的烧炭过程可按温度不同分为两段,分别用不同的动力学方程描述。     

Aromatization of FCC Gasoline Over Modified HZSM-5 Catalyst

Abstract

Zinc and phosphorus incorporated HZSM-5 catalyst was prepared by adopting incipient wet co-impregnation (Zn-P/HZSM-5). Zn-P/HZSM-5 catalyst exhibited the lowest acidity but the highest aromatization activity with stable performance in the studied period of 16 hr. The process conditions on aromatization reaction and the coke deactivation mechanism of Zn-P/HZSM-5 catalyst were studied on a small-scale, fixed bed reactor using FCC naphtha (75–120°C). The weight contents of ZnO and P₂O₅ were 2% and 4%, respectively. Results showed that Zn-P/HZSM-5 catalyst under a temperature of 450°C, liquid hourly space velocity of 1.0 h^?1, and pressure of 0.1 MPa, the conversions of olefins and alkanes are 96.77% and 88.94%, respectively, the contents of olefins, aromatics in liquid product are 6.79% and 74.57%, respectively. Carbon deposition was the major reason for catalyst deactivation due to the catalyst's good performance as a fresh catalyst after regeneration. All of the blending products fitted the standards of Chinese gasoline.     

The catalytic deacidification of acidic crude oil using Cu-doped alkaline earth metal oxide catalysts

Naphthenic acids (NAs) tend to cause operational problems that can lead to the deactivation of catalysts. To overcome the problem, catalytic deacidification was introduced utilizing an ammonia solution in ethylene glycol with the aids of alkaline earth metal catalyst with alumina as a support. The initial total acid number observed for NAs in n-dodecane was 4.21 mg KOH/g. In total, 1,000 mg/L of 0.4% NH₃-EG were used as the acid removal agent. Calcium, barium, and magnesium catalysts were tested in this study. The results showed Cu/Ca/Al₂O₃ was found to be the best catalyst that could be used to enhance the reaction.     

HYDROGEN SULFIDE POISONING OF METHANOL SYNTHESIS Cu-BASED CATALYST∗ (I) INTRINSIC DEACTIVATION KINETICS

Abstract

The hydrogen sulfide poisoning of the methanol synthesis C207Cu-based catalyst was investigated at atmospheric pressure, temperature 250 ～265°C,hydrogen sulfide content 100–280 ppm, based on the methanol composition reaction. The higher the hydrogen sulfide content, the faster the rate of deactivation; the higher the temperature, the faster the rate of deactivation. The intrinsic deactivation rate equations were derived from the experimental data. In addition, the poisoned catalyst was measured by X-ray diffraction.     

甲烷制苯Mo/HZSM-5催化剂失活的研究

用ＤＴＡ－ＴＧ研究了Ｍｏ／ＨＺＳＭ－５上甲烷直接制苯的积炭－烧炭特性。用ＸＰＳ、ＮＨ３－ＴＰＤ、比表面测定考察了催化剂在反应前后性质的变化。结果表明，积炭是一个动态过程，催化剂上的酸中心、表面积和孔体积在反应初期下降较快，而后下降趋缓，与积炭量的变化相一致，这初步说明了积炭是从催化剂上的酸中心和微孔中开始进行的；结焦是Ｍｏ／ＨＺＳＭ－５上甲烷直接制苯失活的主要原因。钼的价态变化以及钼组份在反应中流失也是催化剂失活的因素之一。     

AuCl3-CuCl2/γ-Al2O3乙炔氢氯化催化剂的失活原因分析及再生性能研究

采用γ-Al2O3为载体通过浸渍法制备了AuCl3-CuCl2/γ-Al2O3催化剂,考察其对乙炔氢氯化反应的催化性能,并用比表面积及孔径分析、扫描电镜、能谱仪、傅里叶变换红外光谱、电感耦合等离子体原子发射光谱等表征方法对催化剂的失活原因进行分析。结果表明：在温度150 ℃、压力0.1 MPa、空速120 h-1、V（HCl）：V（C2H2）=1.05的工艺条件下,乙炔转化率达到97% 以上,氯乙烯选择性达到99% 以上,但反应3 h后催化剂活性迅速降低;催化剂表面积炭为其失活的主要原因。将失活催化剂在空气氛围、500 ℃下焙烧1 h后,其活性基本能恢复至新鲜催化剂水平,说明该催化剂具有优异的再生性能。     

STUDIES ON DEPOSITS OF SPENT HYDRO-TREATING CATALYST: A STUDY BY COMBINED ANALYTICAL TECHNIQUES

ABSTRACT

Carbonaceous and non-carbonaceous deposits on a Ni-Mo catalyst, stemming from atmospheric residue upgrading in an ARDS unit were subjected to a combination of analytical techniques, i.e. SF extraction, TGA/DTA/MS, DRIFT, ^l3C CP-MAS NMR, XRD and elemental analysis. Since the spectroscopic features of several components of the deposit interfere with each other a detailed deposit characterization was only achieved by stepwise removal of certain components by SFE deoiling and calcination. SF extraction stripped about 22 wt % of the carbonaceous deposit of the spent catalyst increasing the sp²/(sp³ + sp²) ratio of the NMR-visible carbon from 0 63 to 0.67. TGA revealed three separate temperature ramps for stepwise driving off of deposited material- first ramp, 30° C - 280° C, loss of oil and sulfur from metal sulfides; second ramp, 280° C - 450° C, loss of carbonaceous material like coke; third ramp, 500° C - 680° C, loss of metal sulfates. Further calcination up to 1000° C has no effect on the metal content of the deposition but transforms the framework γ-Al₂O₃ into α-Al₂O₃. Entire burn-off of     

乙炔氢氯化PdCl_2/C催化剂失活原因分析

采用浸渍法制备了PdCl2/C催化剂,考察了PdCl2/C催化剂用于乙炔氢氯化反应制取氯乙烯的催化性能,并用微结构分析仪、扫描电子显微镜、热重分析和电感耦合等离子体发射光谱等表征方法对PdCl2/C催化剂的失活原因进行了分析。实验结果表明,PdCl2/C催化剂具有很高的初活性,在反应温度110~180℃、常压、空速120h-1、V(HCl)∶V(C2H2)=1.15的条件下,乙炔的转化率大于90%,氯乙烯的选择性大于97%,但该催化剂使用寿命很短,失活迅速。表征结果表明,催化剂表面积碳和活性组分PdCl2流失(损失率达40%以上)是导致PdCl2/C催化剂失活的主要原因。通过加入KCl助剂有效地抑制了活性组分PdCl2的流失,PdCl2/C催化剂的性能得以改善。将失活PdCl2-KCl/C催化剂用硝酸氧化除积碳后,催化剂的活性可以恢复。     

MTBE装置催化剂失活原因分析及解决方法研究

针对MTBE装置所用D006催化剂失活较快的问题,从催化反应机理、原料组成、催化剂功能基团脱落,催化剂微孔堵塞,金属离子污染催化剂,有机物污染催化剂,工艺流程等方面进行了分析,找出了其中的主要原因。采用改善工艺过程,对碳四原料烃进行水洗,除去由碱洗过程带来的有机胺,是催化剂的使用寿命延长,取得了满意的效果。     

A Study on Modified HZSM-5 Aromatization for FCC Light Gasoline

Abstract

In this article, the HZSM-5 type zeolite catalysts modified with zinc nitrate and calcium nitrate are prepared by impregnation method. The FCC gasoline (<75°C fraction) is observed and studied on the modified HZSM-5 type zeolite catalysts. The results are that the Z _x -HZSM-5 type zeolite catalysts have a high initial aromatic yield but a rapid deactivation. The C _y -HZSM-5 type zeolite catalysts have a lower aromatic yield and a familiar deactivation comparing to Z _x -HZSM-5. The HZSM-5 type zeolite catalysts modified with bimetal zinc nitrate and calcium nitrate have a rather low initial aromatic yield but a long catalyst life; among them, the C_3.5Z_2.0HZSM-5 has the best performance. And also, the C_3.5Z_2.0HZSM-5 type zeolite catalyst has demonstrated good regenerated performance. After regenerated three times, the catalyst still has a good stability. The reaction operational conditions are also observed and studied. The results are that the optimal reaction temperature is 450–490°C, the liquid hours space velocity (LHSV) is 1 h^?1 and the reaction pressure is 0.1 MPa.     

生物油催化重整制氢过程中催化剂的失活与再生

对生物油在流化床反应器中催化重整制氢过程中催化剂的失活与再生进行了研究。对工业级镍基催化剂(w(NiO)=7.2%)的连续催化及循环失活再生研究表明,催化剂的比表面积、孔径及活性随催化剂失活次数的增加而降低。通过TG-DSC,XRD,SEM等技术分析催化剂失活的原因时发现,失活催化剂上有少量积碳,且随催化剂失活次数的增加而略有增加,但这不是催化剂失活的主要原因;催化剂失活主要是因为NiO晶粒在载体表面烧结长大、使其分散度降低造成的。     

非光气法合成1,5-萘二氨基甲酸甲酯的研究

研究了用碳酸二甲酯（DMC）代替光气与1，5-萘二胺（NDA）反应合成1，5-萘二氨基甲酸甲酯（NDC）的过程。利用Joback法对体系中各物质的基本热力学数据进行了估算，依此计算了该反应在不同温度下的平衡常数。考察了多种金属有机酸盐催化剂对该反应的催化活性，并对反应后的乙酸锌和硬脂酸锌进行了XRD表征。结果表明，该反应在热力学上是可行的；所考察的有机酸锌催化剂中，乙酸锌、三甲基乙酸锌、硬脂酸锌等具有较好的活性，NDC的产率最高可达95．0％；各种有机酸锌的比活性顺序为：苯甲酸锌〈乙酸锌〈三甲基乙酸锌〈戊酸锌〈辛酸锌〈硬脂酸锌。有机酸锌对应衍生酸的pKa值与其比活性有关，当有机酸锌对应衍生酸的pKa值大于4．19时，其锌盐具有较好的比活性。氧化锌的生成是催化剂失活的原因。还推测了以有机酸锌为催化荆的反应机理。     

工业渣油加氢失活催化剂上沉积金属及积炭研究

采用碳-硫元素分析、X射线荧光光谱、X射线衍射光谱、扫描电镜以及热重分析等手段对处理后的工业固定床渣油加氢失活催化剂进行表征。结果表明：保护剂、保护-脱金属过渡剂、脱金属剂、脱金属-脱硫过渡剂主要拦截杂质金属,并以NiV₂S₄的形态存在于催化剂中,脱硫剂、降残炭剂积炭更多。沿物流方向,积炭从软炭向硬炭转变,积炭量增加;金属沉积量和分解温度均先增加后降低,在脱金属剂中沉积量最大,沉积物分子结构最复杂;脱金属-脱硫过渡剂和脱金属剂床层出现严重板结;V元素含量先增加后下降,Fe元素含量逐渐下降,Ni和Ca元素含量的分布则相对平均。沿催化剂颗粒横截面,Fe元素主要沉积在外表面;Ni元素分布较为均匀;V在催化剂边缘处存在较多,中心处沉积量较低,在脱金属剂和脱金属-脱硫过渡剂横截面处呈V形分布,在脱硫剂和降残炭剂横截面处呈U形分布,多数分布在催化剂颗粒表面。在分析基础上提出了催化剂改进建议。     

Study on Methanol Aromatization over Zeolite Catalyst H/ZSM-5 Modified with Zinc Ions in Different Contents

Abstract

The present study describes the performance of H/ZSM-5 catalyst modified with different ZnO contents for the conversion of methanol to aromatics. The contribution of zinc ions was evaluated by analyzing the acid site density, specific surface area, pore structure, and so on, of ZnO/ZSM-5 catalysts. The results showed that the catalytic activity reached a maximum when the content of ZnO was 8 wt%, and the total product yield could reach 56.2%, of which aromatics accounted for 95 wt%.