反应温度对催化裂化汽油芳构化的研究

以中国石油兰州炼油石化公司催化汽油为原料,采用小型固定流化床为芳构化反应装置,考察了反应温度对芳构化产物收率、转化率、马达法和研究法辛烷值、气体产品组成和液体产品组成的影响规律。实验结果表明,随着反应温度的升高,干气、液化气和焦炭收率呈上升趋势,而汽油和柴油收率呈下降趋势,FCC汽油的转化率都在94%左右,且随反应温度的升高先增大后减小;乙烯、丙烯、丁烯、乙烯和总低碳烯烃收率单调增加,而乙烯、丙烯、丁烯、乙烯和丙烯和总低碳烯烃收率的增加幅度各不相同;异构烷烃和烯烃收率随着反应温度的升高逐渐减少,而芳烃的收率和选择性随着反应温度的升高逐渐增加,正构烷烃和环烷烃的收率随着温度的增加先增加后减少。     

Ba-MCM-49分子筛上1-丁烯催化裂解性能的研究

以Ba-MCM-49分子筛为催化剂,纯1-丁烯为原料,考察了钡的含量,反应温度,原料空速及分压对烯烃催化裂解制丙烯、乙烯反应性能的影响。实验表明,适量的钡修饰可以在一定程度上抑制氢转移及芳构化副反应的发生,从而提高了目标产物丙烯和乙烯的选择性。     

连续气相聚合方法

制备乙烯和丙烯的均聚物和共聚物的连续气相聚合方法．其中乙烯、丙烯或含有乙烯和丙烯以及C3-C8的α-单烯烃的混合物在气相聚合反应器的聚合区聚合。反应温度为30-125℃。压力为0．1-10．0MPa。反应在催化剂存在下、含有精细分散聚合物床的气相中进行．为了除去聚合热．将反应气体循环。循环的反应气体离开反应器以后首先通过旋风分离器．为了防止循环气系统中产生聚合物沉积物.     

碳二前脱丙烷前加氢催化剂工艺条件试验

采用浸渍法制备Pd-Ag/α-Al2O3催化剂,采用碳二前脱丙烷前加氢工艺系统考察反应器入口温度、空速和反应压力对催化剂性能的影响。结果表明,随着反应器入口温度升高,乙炔和丙炔+丙二烯转化率提高,乙烯选择性提高至一定值后趋于稳定,丙烯选择性波动不大,正丁烯生成量增加,较为适宜的反应器入口温度为(60~70)℃;随着空速升高,乙炔和丙炔+丙二烯转化率降低,乙烯选择性提高,丙烯选择性变化不大,正丁烯生成量降低,较为适宜的空速为(12 000~14 000)h-1;随着反应压力升高,乙炔转化率和丙炔+丙二烯转化率略增,乙烯选择性降低,较为适宜的反应压力为3.6 MPa。     

甲醇乙烯烷基化反应体系热力学分析

考察了甲醇乙烯烷基化反应体系各独立反应吉布斯自由能随温度变化情况,采用吉布斯自由能最小法计算得到不同反应条件下体系平衡组成。结果表明:该反应体系主要受动力学控制;适当升高温度有利于烯烃生成,且乙烯和丁烯的生成是丙烯生成反应的阻碍点;在只生成丙烯的极端情况下,单独考察生成丙烯的反应,为了提高丙烯产率,需要适当降低反应温度,若综合考虑设备和能耗等因素,体系存在最佳反应压力和进料比(乙烯与甲醇摩尔比)。     

HZSM-5催化甲醇制丙烯工艺条件的考察

以工业应用的HZSM-5为催化剂,在连续固定床反应器中考察了反应温度和甲醇分压对甲醇制丙烯反应产物的影响,发现当温度大于450℃时,随着温度的升高,甲醇的转化率都能达到99%以上,乙烯和丙烯的总选择性增加,低碳烷烃选择性增加,高碳产物选择性下降;随着甲醇分压降低,甲醇转化率下降,产物丙烯/乙烯质量比(P/E比)增加,丙烯在甲醇分压为33 kPa时达到最高值,而当分压极低时,催化剂快速失活。从转化率、丙烯选择性、P/E比以及低碳烯烃产物选择性等多方面综合考虑,甲醇转化制丙烯的反应温度优选470℃,并建议甲醇分压为33 kPa。     

干气中乙烯丙烯在活性炭上的动态吸附和脱附特性研究

为了建立干气中乙烯、丙烯的吸附分离方法,搭建了考察乙烯、丙烯在活性炭上动态吸附和脱附特性的实验装置,测定了温度为298~333 K、压力为0.2~1.0 MPa条件下,干气中甲烷、乙烯、乙烷、丙烯、丙烷等组分在活性炭上的动态吸附容量,获得各组分的吸附等温线并计算乙烯/丙烯的分离因子,确定活性炭对乙烯、丙烯有很好的吸附选择性。采用升温和惰性气体吹扫相结合的方式进行活性炭的再生,考察了温度和吹扫气流速对再生效果的影响,得到最佳再生条件:温度为373 K,氢气流速为60 mL·min-1,吹扫时间为35 min。活性炭经过多次吸附和再生后,各组分的吸附容量没有显著下降。     

HZSM-5催化剂上甲醇制丙烯反应条件的研究

以HZSM-5分子筛为催化剂,在固定床反应器中考察了反应温度和原料空速对甲醇制丙烯性能的影响。结果表明,随着反应温度的升高,乙烯和丙烯选择性均增加,但温度过高容易引起催化剂的失活;而随原料空速的增大,甲醇转化率、乙烯和丙烯的选择性均呈下降趋势。最佳的反应条件为反应温度为460°C,原料液时空速为1.4 kg(Methanol)/kg(cat.).h。对添加粘结剂与未添加粘结剂成型后的催化剂性能比较,表明添加粘结剂成型后,甲醇转化率和丙烯选择性有所下降。     

MTP反应工艺条件优化的研究

在固定床反应器上,以改性处理HZSM-5为催化剂,考察反应温度、进料空速、水醇比对MTP反应的影响。结果表明:乙烯、丙烯的选择性会随着反应温度升高而升高,但过高的温度会使催化剂失活;空速增加,目标产物选择性降低;原料中加入适量的水有利于反应进行。优选出最佳反应条件为:反应温度450℃,原料空速3 h~(-1),水醇比2,在此条件下丙烯的选择性达49.2%。     

不同硅铝比ZSM-5催化剂上的MTO反应性能

由于原油供应的可预见性短缺,急需开辟新的烯烃合成路线.在固定床上,以甲醇为原料、ZSM-5为催化剂,对MTO反应进行了研究,考察了反应时间、反应温度、进料水醇摩尔比以及催化剂硅铝比对甲醇制烯烃反应的影响.结果表明,反应时间对乙烯和丙烯的摩尔比有明显的影响;反应温度在一定的范围内升高可延长催化剂使用时间,但同时也使副产物增多;水醇摩尔比对乙烯加丙烯的选择性的影响不是很明显;硅铝比为38的ZSM-5催化剂上反应产物中的初始乙烯和丙烯摩尔比较高.     

Spatial confinement effects of cage-type SAPO molecular sieves on product distribution and coke formation in methanol-to-olefin reaction

Three kinds of 8-membered ring silicoaluminophosphate (SAPO) molecular sieves with different cage structures, SAPO-34, SAPO-18 and SAPO-35, were employed in methanol-to-olefin (MTO) reaction. The main products over SAPO-34 and SAPO-18 were propene and butenes, whereas ethene and propene especially ethene were predominantly generated over SAPO-35. Coke species formation greatly depended on reaction temperature and varied systematically with cage size. The differences in production distribution and generated coke species in the MTO reaction suggest great spatial confinement effects imposed by cage structure of SAPO catalysts.     

Metathesis of Ethene and Decene to Propene over a WO3/SiO2 Catalyst

Metathesis between decene and ethene to propene over a WO₃/SiO₂ catalyst was studied. The dependency of the conversion of decene, selectivity to propene, and working lifetime of the catalyst on ethane‐to‐decene molar ratio and temperature was evaluated. Low temperature was found to be favorable to the production of C₆–C₉ olefins, while high temperature enhanced C₁₀₊ olefins. The working lifetime of the catalyst decreased with the weight hourly space velocity. The optimum reaction conditions for the metathesis process of decene and ethene to propene were determined. An obvious induction period was found to exist in the metathesis reaction.     

1-丁烯催化裂解制丙烯和乙烯反应性能的研究

以MCM-49分子筛为催化剂,纯1-丁烯为原料,考察了反应压力和空速对烯烃催化裂解制丙烯,乙烯反应性能的影响.选择适宜的反应压力和空速条件能够有效地抑制副反应,从而提高丙烯,乙烯的总产率。     

Infrared studies of ethene hydrogenation over ZrO2

Hydrogenation of adsorbed ethene over ZrO₂ at low temperature was observed by in situ infrared transmission spectroscopy. It was found that di-hydrogen was directly activated on the site where ethene was already adsorbed, which was confirmed by the comparison of adsorbed species produced during the reaction and adsorbed ethane species.     

Catalytic cracking of 1-butene to propene and ethene on MCM-22 zeolite

Catalytic cracking of butene to propene and ethene was investigated over HMCM-22 zeolite. The performance of HMCM-22 zeolite was markedly influenced by time-on-stream (TOS) and reaction conditions. A rapid deactivation during the first 1 h reaction, followed by a quasi-plateau in activity, was observed in the process along with significant changes in product distributions, which can be attributed to the fast coking process occurring in the large supercages of MCM-22.

Properly selected reaction conditions can suppress the secondary reactions and enhance the production of propene and ethene. According to the product distribution under different butene conversion, we propose a simple reaction pathway for forming the propene, ethene and by-products from butene cracking.

HMCM-22 exhibited similar product distribution with the mostly used high silica ZSM-5 zeolite under the same conversion levels. High selectivities of propene and ethene were obtained, indicating that the 10-member ring of MCM-22 zeolite played the dominant role after 1 h of TOS. However, MCM-22 exhibited lower activity and stability than that on high silica ZSM-5 zeolite with longer time-on-stream.     

Co-reaction of ethene and methanol over modified H-ZSM-5

Co-reaction of ethene and methanol was carried out over HZSM-5, P-La modified ZSM-5 (PLaHZ) and hydrothermal-treated PLaHZ catalysts. Hydrothermal treatment at high temperature sharply reduced the acidity of the catalyst, on which the direct conversion of ethene or methanol/dimethyl ether was almost completely suppressed. Co-feeding of ethene and methanol over the said catalyst resulted in considerable conversion of both reactants. Meanwhile, high propene selectivity (ca. 80%) was obtained at lower conversions. The methylation of ethene by methanol was responsible for the enhancement of conversions and propene selectivity in the co-reaction system. The further methylation of propene and the cracking of higher olefins were also operative under current reaction conditions.     

催化裂化干气与混合C4组合进料制丙烯的研究

基于提高烯烃利用率和增产丙烯的目的,以催化裂化(FCC)干气和混合C4组合原料来制备丙烯,考察了混合比例、空速、反应温度等因素对产物分布的影响。结果发现,当以生产丙烯为目的时,混合比例和空速分别为3.3和118 m in-1时,丙烯收率可获得最大值33.2%(质量分数)。在350~675℃内,随温度升高,裂解深度增加,乙烯、丙烯等小分子烯烃含量增加,丁烯含量则是先减小,当温度高于600℃时又有所回升,推测高温下丁烷为烯烃的生成做了一部分贡献。     

Conversion of ethanol over zeolite H-ZSM-5

The conversion of ethanol over H-ZSM-5 was studied as a function of ethanol partial pressure, reaction temperature, weight hourly space velocity and Si/Al ratio. The results obtained were in qualitative agreement with most of those in the literature. Combination with all published results to give a significant regression model was not possible due to the large scatter of the data from various scientific groups. In mechanistic investigations, temperature programmed reaction measurements of ethanol, diethyl ether and ethene were performed. The formation of ethene from ethanol via direct elimination or from diethyl ether as intermediate could be confirmed. In the conversion of ethanol/water mixtures, the product distribution did not change significantly up to a water content of 60 wt%. Then, a pronounced increase of ethene formation and a considerable decrease of the yields of aromatics was observed. When several reaction mixtures from syngas conversion to ethanol were converted over H-ZSM-5, the coking rate depended on the product distribution in the feed. Product mixtures from processes with higher amounts of compounds having an unfavourable C/H ratio led to rapid deactivation of the zeolite.     

Structure Sensitivity of the Catalytic Oxidation of Ethene by Silver

The partial oxidation of ethene to produce ethene oxide using silver catalysts has received considerable attention because it is the basis of a several billion dollar per year industry. It is also of fundamental interest because silver is the only metal to catalyze the production of ethene oxide in economic yields. It is not surprising to find that the mechanism of the catalytic reaction and the reactor engineering associated with the commercial process have been extensively reviewed.