过渡金属氧化物担载型USY分子筛对神东煤催化热解行为的影响

利用粉-粒流化床热解实验装置,研究了过渡金属氧化物改性的USY分子筛对神东煤热解行为的影响。结果表明:过渡金属氧化物改性后USY分子筛骨架结构未发生变化,酸量变化显著。催化剂对神东煤一次热解挥发分的催化作用明显,半焦收率基本保持在66%左右;在实验所选五种催化剂作用下热解挥发分的脱氧反应都增强,热解气中CO和CO_2的收率明显增加,液体产物收率下降,强酸性导致积碳严重,双金属改性后积碳情况改善。USY分子筛对轻质芳烃的形成具有较高的催化活性,其酸性中心能促进焦油中含氧化合物、稠环芳烃和脂肪烃向萘类芳烃转化,负载WO_3后会抑制焦油中萘类芳烃的生成,NiO引入后催化剂的双金属活性导致此抑制作用更为明显,且NiO的裂解性和脱氢性能会显著增加焦油中脂肪烃的含量和气体中H2的收率。     

甲烷催化活化与低阶煤热解耦合对热解产物的影响

为考察甲烷催化活化与低阶煤热解耦合对煤热解产物的影响,以榆林锦界煤为研究对象,以管式炉为反应器,以HZSM-5为载体,分别制备了Mo/HZSM-5,Ni/HZSM-5,Co/HZSM-5,Zn/HZSM-5和Fe/HZSM-5催化剂,考察了催化剂种类、热解温度(600℃,650℃,700℃,750℃,800℃)和催化剂负载量(1%,2%,3%,4%,质量分数)对热解产物分布的影响。结果表明:在热解温度为650℃,采用Mo负载量为2%的Mo/HZSM-5催化剂的条件下焦油产率最高,在此最优工艺条件下焦油产率为13.26%,较煤单独热解的焦油产率提高了31.5%。     

热解温度和反应气氛对输送床煤快速热解的影响

在连续进料量为1.2 kg·h~(-1)的输送床反应器中考察了热解温度和反应气氛对不连沟次烟煤快速热解的影响。N_2气氛下,随着煤热解温度升高,焦油产率先增加后减小,600℃时达到最大值10.3%;对应的半焦产率下降,气体产率以及气油比增加。高温促进了煤挥发分的释放以及挥发分在气相中的二次反应,部分产物从固相和液相产品转化为气相产品,氢气、甲烷和乙烯等气体组分的产率明显增加。700℃下,H_2气氛能够抑制挥发分二次反应的发生,起到稳定自由基和加氢的作用,显著提高焦油产率和油品品质,同时有利于甲烷的生成。CO气氛在一定程度上同时提高了轻质和重质焦油产率。CO_2和水蒸气能够促进焦油的二次反应,特别是重质焦油的裂解,具有一定的提质作用,但会导致焦油产率下降。CH_4气氛促进了重质焦油组分的生成,使得热解焦油产率提高。     

内蒙古褐煤流化热解反应特性试验研究

基于小型流化床评价装置研究了内蒙古褐煤流化热解反应特性,考察了温度、压力、线速率和催化剂负载量对热解产物分布、热解气组成、半焦组成以及膨胀率的影响。研究结果表明:随着热解温度升高,热解气产率大幅升高。随着热解压力增加,热解气产率和焦油产率逐渐降低。随着线速率提高,热解气产率和焦油产率呈明显增大的变化趋势。添加催化剂后热解更加完全,半焦中残留的挥发分降低,煤颗粒的塑性软化能力升高,膨胀率逐渐增大。     

热解温度和反应气氛对输送床煤快速热解的影响

在连续进料量为1.2 kg·h^-1的输送床反应器中考察了热解温度和反应气氛对不连沟次烟煤快速热解的影响。N₂气氛下,随着煤热解温度升高,焦油产率先增加后减小,600℃时达到最大值10.3%;对应的半焦产率下降,气体产率以及气油比增加。高温促进了煤挥发分的释放以及挥发分在气相中的二次反应,部分产物从固相和液相产品转化为气相产品,氢气、甲烷和乙烯等气体组分的产率明显增加。700℃下,H₂气氛能够抑制挥发分二次反应的发生,起到稳定自由基和加氢的作用,显著提高焦油产率和油品品质,同时有利于甲烷的生成。CO气氛在一定程度上同时提高了轻质和重质焦油产率。CO₂和水蒸气能够促进焦油的二次反应,特别是重质焦油的裂解,具有一定的提质作用,但会导致焦油产率下降。CH₄气氛促进了重质焦油组分的生成,使得热解焦油产率提高。     

HZSM-5/MCM-41对小球藻催化热解的影响

以HZSM-5/MCM-41为催化剂,在管式炉内对小球藻进行了催化热解研究。考察了HZSM-5/MCM-41复合催化剂中MCM-41的添加比例对小球藻热解产物影响,并采用GC-MS和元素分析对所制取生物油进行了表征。结果表明:与HZSM-5催化剂相比,90%HZSM-5与10%MCM-41混合后生物油中3,7,11,15-四甲基-2-十六烯的选择性最好。羧酸类和含氮物质分别降低12.85%、43.97%,脂肪烃和芳烃的质量分数之和达到50.34%,且不存在硬脂酰胺和油酸腈等物质。根据元素分析可知,10%的MCM-41的引入使生物油含氧量降低23.52%,O/C原子比明显降低,H/C原子比得到提高,热值达到32.995 MJ·k-1,且油品组成与生物柴油接近。热重实验表明,分子筛催化剂失活主要是由于积炭的产生,HZSM-5/MCM-41具有良好的稳定性。随着催化剂用量的增加,生物油热值增加,同时含水量也增多,HZSM-5/MCM-41与小球藻质量比例为1:5时,生物油产率最高。     

煤热解过程分析与工艺调控方法

通过煤热解技术获取紧缺的油气资源是低阶煤清洁利用的有效途径之一。针对煤热解工艺存在焦油产率与品质难以控制以及焦油中粉尘含量高等关键技术问题,从煤的热解反应机理出发,详细探讨了热解挥发分二次反应的种类和发生条件以及影响热解过程的主要因素,结合煤热解技术应用,总结了逆向传热与传质所导致的挥发分气相二次反应是焦油产率下降的主要原因;同时,分析了热解过程中煤颗粒破碎机理以及煤热解过程中粉尘的主要来源。在前人研究结果的基础上,提出控制热解挥发分的流动方向从高温区向低温区流动、热解耦合气化以及耦合原位的焦油提质与除尘等方法可以调控煤热解过程,抑制重质焦油生成、提高焦油中轻质组分含量以及减少焦油中的含尘量,从而实现煤的定向热解。     

煤热解过程分析与工艺调控方法

通过煤热解技术获取紧缺的油气资源是低阶煤清洁利用的有效途径之一。针对煤热解工艺存在焦油产率与品质难以控制以及焦油中粉尘含量高等关键技术问题,从煤的热解反应机理出发,详细探讨了热解挥发分二次反应的种类和发生条件以及影响热解过程的主要因素,结合煤热解技术应用,总结了逆向传热与传质所导致的挥发分气相二次反应是焦油产率下降的主要原因;同时,分析了热解过程中煤颗粒破碎机理以及煤热解过程中粉尘的主要来源。在前人研究结果的基础上,提出控制热解挥发分的流动方向从高温区向低温区流动、热解耦合气化以及耦合原位的焦油提质与除尘等方法可以调控煤热解过程,抑制重质焦油生成、提高焦油中轻质组分含量以及减少焦油中的含尘量,从而实现煤的定向热解。     

不同种类分子筛催化热解纤维素

以纤维素为原料,在固定床反应器上进行了催化热解研究。采用的催化剂分别为ZSM-5(38)、Al-MCM-41(40)、ZSM-5(38)/Al-MCM-41(40)。本研究通过改变催化剂种类,考察其对生物质热解产物及生物油成分的影响。实验结果表明:添加催化剂后,生物油产率降低,且其含水率也有所增加。与未添加催化剂相比,醇含量有明显提高。酮类、醛类、酯类、醚类、呋喃等含氧化合物及酸含量均有所降低,芳香类化合物有小幅升高趋势。     

胜利褐煤快速热解特性

为考察热解温度对热解产物品质及挥发分残留的影响,在10 kg/h自制褐煤快速热解提质试验设备上,以胜利褐煤为试验原料,考察了400~900℃热解提质温度对热解产物产率、气体产物组成、半焦微观结构以及残余挥发分的影响。结果表明,随着热解温度的升高,半焦产率逐渐降低,气体产率升高,焦油的产率先升高后降低,700℃时焦油产率最大;热解气体中的CO_2随着热解温度的升高逐渐降低,H_2和CO含量随着热解温度的升高而增加;随着热解温度的升高,挥发分不断释放导致半焦含氧官能团以及高活性的小的缩合芳环减少;热解温度≥700℃,半焦残留的挥发分较低,固定碳较多,基本满足电石用焦的要求。     

Effects of metal modifications of Y zeolites on sulfur reduction performance in fluid catalytic cracking process

The acidity of catalytically active component, e.g., ultra stable Y zeolite (USY), plays an important role in determining their cracking activity and selectivity. To develop advanced sulfur reduction catalytic cracking catalysts, different type of elements were used to modify USY and the resulting catalysts were evaluated in a confined fluidized bed reactor and a micro-activity testing unit. The relation between the acidity of the zeolite and the conversion of sulfur compounds as well as the distributions of fluid catalytic cracking (FCC) products were discussed. The results showed that the rare earth (RE) metal can stabilize the catalyst and increase the conversion, but cannot increase the selectivity to thiophene compounds; V can reduce the sulfur content by 36.3 m%, but decreases the overall conversion compared with the base catalyst. An optimum catalyst was obtained by the combined RE and V modification, over which the sulfur content in FCC gasoline can be decreased and the selectivity for the target products can be improved, with the sulfur content reduced by 30 m% and the selectivity to coke even decreased by 0.20 m% at a comparable conversion level of the base catalyst.     

Pilot synthesis and commercial application in FCC catalyst of MCM-41 zeolite

MCM-41 zeolite in the grade of 600 kg was successfully synthesized and the MCM-41 added FCC catalyst was firstly prepared. The results indicate that the pilot samples of mesoporous Al-MCM-41 bear the typically uniform mesopore structure and considerable acidity and hydrothermal stability. The MCM-41 added FCC catalyst is positively capable to crack heavy oil feedstock, in which the yields of the diesel and lighter oil increased 1.85 and 3.47%, respectively and coke yield decreased 0.29%. Commercial application in FCCU indicate that optimization of nanopores of MCM-41 added faujasite zeolite might result in an industrial process to design novel FCC catalysts.     

Composites as cracking catalysts in the production of biofuel from palm oil: Deactivation studies

Composite catalysts HZSM-5/alumina (CZA) and Al-MCM-41/alumina (CMA) were synthesized and tested for their catalytic cracking activity in the production of biofuel from palm oil. Both composite catalysts were characterized for their structure, acidity and surface morphology. The addition of alumina in the composite catalysts improved their hydrothermal stability due to the changes in the surface morphology. The deactivation of the catalysts was studied by obtaining time on stream data by varying the palm oil to catalyst ratio of 8–16. The deactivation data were analyzed using different activity models and the deactivation parameters were determined.     

催化剂结构与焦油模型化合物裂解行为的关联性

以Ni（NO₃）₂·6H₂O为镍源,分别以HZSM-5（Si/Al=25）、HZSM-5（Si/Al=50）、HZSM-5（Si/Al=200）、USY、Al₂O₃为载体制备了5种镍基催化剂,采用XRD、H₂-TPR、BET、NH₃-TPD等方法对其进行了表征,在固定床反应器中考察了上述催化剂对煤焦油模型化合物甲苯+芘的催化裂解性能。结果表明,相比惰性载体石英砂,在催化剂作用下,液相产物中轻质芳烃种类明显增多。3种Ni/HZSM-5催化剂的比表面积和平均孔径较为接近,然而酸性中心数量最多的Ni/HZSM-5（Si/Al=25）,对甲苯+芘的裂解能力最强,体现为液体产物收率最低（仅为15.95%）,气产率和析碳率均最高,分别达16.73%和67.32%。在酸性中心数量相近的Ni/HZSM-5（Si/Al=200）与Ni/Al₂O₃作用下,液体产物收率差别较小,但后者的芘裂解率比前者高41.47%,主要是由于后者的平均孔径比前者高1.64倍,说明平均孔径大有利于重质组分芘的裂解。综合考虑液体产物收率、气产率、析碳率和芘的裂解率,Ni/Al₂O₃更适合甲苯+芘裂解反应体系。     

HZSM-5分子筛上甲苯择形甲基化反应积炭行为探讨

将水热合成法制备并改性的HZSM-5分子筛催化剂应用于甲苯甲醇甲基化反应,催化剂表现出良好的甲苯转化率和二甲苯对位选择性。采用程序升温氧化法、固体紫外-可见吸收光谱、核磁共振法和气相色谱串联质谱法等研究催化剂的积炭行为。结果表明,反应介质甲醇中的氧未参与积炭形成,积炭成分较为单一,均由碳氢两种元素组成。积炭分为可溶的芳烃和稠环芳烃及其衍生物以及不可溶稠环芳烃、石墨前驱体、石墨等中的一种或几种混合物。甲苯与甲醇作为反应底物同时存在也决定了可溶性成分中单甲基或多甲基取代芳烃占大多数。早期积炭主要分布于分子筛孔道,积炭组成和分布由分子筛孔道结构和外表面酸性、反应物性质与反应条件决定。     

Synthesis of dypnone using SO4/Al-MCM-41 mesoporous molecular sieves

The mesoporous molecular sieves Al-MCM-41 with Si/Al ratio equal to 16, was synthesized under hydrothermal conditions using cetyltrimethylammonium bromide (CTMA⁺Br⁻) as surfactant. The same ratio of Al-MCM-41 materials was impregnated using sulfuric acid, the materials as sulfated Al-MCM-41 (SO₄²⁻/Al-MCM-41). The mesoporous materials viz Al-MCM-41 and SO₄²⁻/Al-MCM-41 were characterized using several techniques e.g. ICP-AES, Nephelometer, XRD, FT-IR, TG/DTA, N₂-adsorption, solid-state-NMR, SEM and TPD-pyridine. ICP-AES studies indicated the presence of Al in the mesoporous materials. Nephelometer studies indicated the SO₄²⁻ presence of the SO₄²⁻/Al-MCM-41. XRD studies indicated that the calcined materials of Al-MCM-41 and SO₄²⁻/Al-MCM-41 had the standard MCM-41 structure. The surface area, pore diameter, pore volume and wall thickness of the mesoporous materials were calculated by BET and BJH equations, respectively. Crystallinity, surface area, pore diameter and pore volume of SO₄²⁻/Al-MCM-41 decreased except wall thickness and the expelling aluminum from the Al-MCM-41 framework increased the Lewis acidity. FT-IR studies indicated that Al-ions were incorporated in the hexagonal mesoporous structure of Al-MCM-41 and sulfuric acid was impregnated into hexagonal Al-MCM-41 materials. The thermal stability of as-synthesized Al-MCM-41 materials and SO₄²⁻/Al-MCM-41 materials were studied using TG/DTA. The environments of the Al-ions coordinated in the silica matrix were determined by ²⁷Al-MAS-NMR. The morphology of Al-MCM-41 and SO₄²⁻/Al-MCM-41 was determined by SEM. The total acidity of Al-MCM-41 and SO₄²⁻/Al-MCM-41 materials was determined by TPD-pyridine. The catalytic results were compared with those obtained by using sulfuric acid, amorphous silica–alumina, H-β, USY and H-ZSM-5 zeolites. The SO₄²⁻/Al-MCM-41 catalyst exclusively forms the product of dypnone from self-condensation of acetophenone molecules due to higher number of Lewis acid sites and has much higher yields than other catalysts except USY.     

不同类型分子筛催化剂上香兰素丙二醇缩醛的合成

以香兰素和1,2－丙二醇为原料,HZSM－5、HY、USY、HB、HMCM－22和HMCM－41不同类型分子筛为催化剂,催化合成了香兰素1,2－丙二醇缩醛。对上述分子筛进行了N2吸附—脱附、吸附吡啶的FT－IR表征。结果表明,HMCM－22分子筛具有最高的活性,各种分子筛活性顺序为：HMCM－22〉H13〉USY〉HY〉HZSM－5〉HMCM－41。HMCM－22分子筛具有最高的催化活性,因为它具有最大的二次孔的体积和适宜的酸性。     

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition met-alion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygena-tion (Edeoxygenation),lightweight (Elightweight) from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Elightweight of CTA pyrolysis volatiles over USY is 9.65％,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85％.Additionally,the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions (Mo,Co) and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY (4032 mg·kg-1),Co/USY (4363 mg·kg-1) and Mo/USY (4953 mg·kg-1) were increased by 27.03％,38.19％ and 54.78％,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.     

Vapour Phase Oxidation of Cumene by Molecular Oxygen over MCM-41 Supported Cobalt Oxide Catalyst

Si-MCM-41 and Al-MCM-41 supported cobalt oxide catalysts were prepared and characterized by XRD. The surface area, pore size and wall thickness was calculated by applying BET equation and BJH method using nitrogen sorption technique. DR UV-VIS confirm the presence of cobalt oxide as isolated particle in the framework positions of the MCM-41 mesostructure. The vapour phase oxidation of isopropyl benzene with CO₂-free air as the oxidant was studied over cobalt oxide supported unwashed and washed Si-MCM-41 and Al-MCM-41 catalyst. Isopropyl benzene conversion increased with increase in temperature from 200 to 300 °C, but at 325 °C it decreased. Formation of coke was noted at all the temperatures. Cumenehydroperoxide, 1,2-epoxyisopropylbenzene, acetophenone and styrene were the products observed in this reaction. Of the products cumenehydroperoxide was found to be more selective over all the catalysts. Both unwashed and washed catalysts were found to have nearly the same activity. Due to more dispersion, the active sites in the latter catalysts compensates its low cobalt oxide content in producing activity equal to the former catalysts. The study of time on stream indicated decrease in conversion due to coke formation.     

几种沸石分子筛的催化裂化性能研究:2活性稳定性和反应性能

分别制备了含有REHY、HZSM-5和Hβ分子筛的模型催化剂,用固定床微反装置研究模型催化剂的活性保留率,用ACE装置研究模型催化剂的重油裂化性能。结果表明:①含有REHY分子筛的模型催化剂的活性保留率最高,100%水蒸气减活处理17 h后的活性保留率为47%,而含有HZSM-5分子筛的模型催化剂的活性保留率仅为25%;②含有REHY分子筛的模型催化剂的重油和焦炭产率分别为15.90%和5.05%,具有重油转化能力强,焦炭产率低等特点;HZSM-5分子筛的重油转化能力和汽油产率最低(34.52%,23.86%),但有较高的丙烯产率和丙烯选择性。