重油催化裂化装置抗重金属镍污染的措施

重金属镍和钒在催化裂化催化剂上的沉积会导致催化剂的失活和选择性下降。大港油田炼油厂针对催化原料中重金属镍含量高的实际情况,采取了使用金属钝化剂、干气预提升、定期卸出部分平衡剂并补充新鲜剂、选用抗镍能力强的催化剂等一系列钝镍措施,取得了较好的工业应用效果。     

钒对裂化催化剂的影响及流化催化裂化抗钒助剂的开发

研究了钒对分子筛和催化剂性能的影响 ,并开发出一种高活性固体的流化催化裂化抗钒助剂。随着钒含量的增加 ,分子筛的结晶度、比表面积、孔体积呈单调下降 ;而催化剂的催化活性大幅降低 ,选择性变差。抗钒助剂与其他类型的催化剂复配后 ,显示出较强的抗钒性能 ,能明显改善裂化产物的汽油、焦炭的选择性。     

流化床催化裂化催化剂钒污染及捕钒剂的研究与应用进展

简述了钒在催化裂化过程中对催化剂所产生的危害及污染机理,讨论了在污染中钒与有关因素的相互作用,对国外捕钒剂的应用情况进行了重点阐述,最后对国内捕钒剂的研究现状进行了分析.     

重油催化裂化的金属钝化剂

重油中所含的金属Ni、V、Na在流化催化裂化 (FCC)过程中 ,会污染催化剂 ,导致催化剂失活。本文综述了国内外金属钝化剂的研究进展 ,提出研制无毒、高效以及多功能的金属钝化剂是今后发展的方向。     

DFP新型钒镍钝化剂在RFCCU的工业应用

在研究重金属镍、钒对烃类裂化催化剂中毒机理的基础上,通过具有一剂多能和协同作用元素间的复配和优化,并考虑工业应用的可行性和成本,研制了无毒、高效和稳定性好的DFP抗钒、抗镍双功能水溶性钝化剂,在乌鲁木齐石化公司1.2 Mt/a的重油催化裂化装置(RFCCU)进行了工业应用试验。结果表明,当原料油中掺质量分数为39％～42％的减压渣油,平衡剂上钒质量分数高达7.5×10^－9～9×10^－9,镍质量分数为5×10^－9～6×10^－9条件下,使用DFP钝化剂与国产钝化剂MP相比,轻质油收率提高0.45%,焦炭产率下降16％～20%,氢气产率下降25％～30%,平衡剂活性指数提高4～5个单位,使用方便,有显著的经济效益和社会效益。     

钒对催化裂化催化剂活性的影响

随着石油加工技术的拓展,二次加工原料使用越来越广泛,但同时带来了重金属对催化裂化催化剂中毒问题。镍对催化裂化催化剂的中毒作用已被国内认识,但钒对催化裂化催化剂的中毒影响尚未引起人们重视。     

催化裂化金属钝化剂研究进展

FCC 过程中, 沉积在沸石催化剂上的金属镍和钒会导致催化剂严重失活, 加入金属钝化剂是解决上述问题的经济有效的办法。本文综述了沸石催化剂上镍和钒的污染及其钝化机理,以及金属钝化剂的研究进展, 指出研制无毒、高效的钝镍剂、钝钒剂以及钝镍钝钒双功能钝化剂是今后发展的主要方向。     

催化裂化催化剂实验室污染老化方法研究

介绍了一种全新的催化裂化催化剂实验室污染老化方法,该方法可用于催化裂化催化剂的老化、金属污染、金属钝化和反应评价,具有可连续进料、连续老化再生、连续添加新鲜催化剂等特点.该方法所得的老化污染剂与工业平衡剂性质基本相近,所得产品分布和产品性质能完全用于模拟工业化装置.     

不同老化气氛对催化裂化捕钒剂性能的影响

通过改变老化处理气氛,研究其对催化裂化捕钒剂性能的影响。在水蒸汽和氮气气氛下,含有捕钒组分的催化剂与不含捕钒组分的催化剂催化活性接近,捕钒组分的捕钒效果不显著。在水蒸汽和空气气氛下,随着空气体积分数由0增加到50%,不含捕钒组分的催化剂微反活性由58%升高到69%,重油转化率由68. 82%升高到74. 02%;含有捕钒组分的催化剂微反活性由60%升高到73%,重油转化率由70. 04%升高到77. 10%,焦炭和干气选择性也优于不含捕钒组分样品,体现了捕钒组分的捕钒效果。通过控制老化气氛中SO2质量分数为0或0. 16%,考察SO2对捕钒组分的影响,结果表明,SO2对此捕钒组分的性能影响较小。     

化学吸附法脱除FCC汽油中含硫化合物的实验研究

吸附法脱硫具有低投资、低操作成本的优点,尤其是化学吸附更具有高硫脱除率的特点。研究了汽油的化学吸附脱硫方法,优化了吸附脱硫工艺条件。     

Catalytic behaviour of nickel and iron metal contaminants of an FCC catalyst after oxidative and reductive thermal treatments

The catalytic effects of nickel and iron deposited on an FCC (fluidized catalytic cracking) catalyst via metal naphthenates were studied in a micro activity test (MAT) unit after both oxidative and reductive treatments of the catalyst samples.The dehydrogenation activity of nickel was found to be close to the dehydrogenation activity of vanadium – and not several times higher than that of vanadium as is often reported – when deposited on the commercial FCC catalyst used in this study followed by steam deactivation (oxidative treatment) at 760 °C. However, the dehydrogenation activity of nickel was significantly intensified after post-treatment with a CO/N₂ mixture at this temperature (reductive treatment).The results show that iron did not have a dehydrogenation activity after steaming, but had a significant dehydrogenation activity after steaming when followed by exposure to the CO/N₂ mixture at 760 °C. The results indicate that the presence of deposited iron was inducing an additional catalytic cracking activity for the FCC catalyst.It was observed that co-impregnation of equal loadings of nickel, iron and vanadium on the FCC catalyst led to a considerably higher dehydrogenation activity than could be expected from the catalytic behaviour of the separate elements. The dehydrogenation activity was however slightly reduced by the reductive treatment as the reduced dehydrogenation activity from the lower oxidation state of vanadium (V³⁺) more than compensated the increased dehydrogenation activity of iron and nickel. A slightly increased gasoline production after the reductive treatment of the co-impregnated sample was a result of the increased production of gasoline from the FCC catalyst itself, which more than compensated for the reduced gasoline production from nickel.     

Effect of the carboxymethyl chitosan on removal of nickel and vanadium from crude oil in the presence of microwave irradiation

The effects of carboxymethyl chitosan (CT-50) on removal of nickel and vanadium from pipeline crude oil in the presence of microwaves were investigated. CT-50 was synthesized from chitosan (CTS-50, molecular weight 50 million). CTS-50 and CT-50 were characterized by infrared spectroscopy and scanning electronic microscopy. CT-50 was used to remove nickel and vanadium from pipeline crude oil. The effects of several factors, such as initial temperature, microwave time, microwave power and CT-50 dose on nickel and vanadium removal efficiencies from crude oil were evaluated. The results indicated that removal of nickel and vanadium from crude oil using CT-50 was far more efficient than that using CTS-50 under the same conditions. A reaction temperature of 60 °C, a microwave power of 300 W, a microwave time of 2 min, and a CT-50 dose of 500 mg/L, the nickel and vanadium removal efficiencies from crude oil reached up to 69.79% and 93.66% respectively. Microwaves were thought to enhance the molecular motion and the stable molecular structure of organic compounds of nickel and vanadium became loose in the high-energy state, and they were adsorbed in CT-50 and reacted with the amino (-NH₂) and carboxylic (-COO⁻) groups in the CT-50 molecule.     

Long-term electrolytic hydrogen permeation in nickel and the effect of vanadium species addition

Nickel cathodes have been found to become deactivated under long-term polarization in the H₂ evolution region during alkaline water electrolysis. The cause of deactivation was examined using steady state polarization and measurement of hydrogen permeation through nickel foil in 8 mol/l KOH at 70 °C and 100 mA/cm². The long-term (over 50 h) permeation behaviour was explained by formation and growth of a nickel hydride phase. The rise in hydrogen overpotential was ascribed to an increase of the hydrogen surface coverage on the newly formed hydride. The effect of an electrolyte additive (a vanadium salt) on the hydrogen overpotential and permeation rate was also investigated. Upon addition of dissolved V₂O₅, the permeation rate was found to increase quickly and then slowly decrease to a steady value close to that measured for hydride-free nickel. Meanwhile, the hydrogen overpotential was observed to recover back to nearly its initial value for fresh nickel. The exhibited behaviour was attributed to decomposition of the hydride phase, after deposition of a vanadium-bearing compound. The prolonged contact between Ni and V was proposed as the main reason for hydride decomposition. The addition of more vanadium had no further result on the hydrogen overpotential.     

钒对FCC催化剂脱除噻吩类硫化物性能的影响

催化裂化过程(FCC)中使用催化剂脱硫对生产清洁燃料具有重要意义。文中通过文献调研,阐述了噻吩类硫化物在FCC催化剂上的裂化依赖于B酸和L酸的协同作用原理,指出以L酸碱对化合物修饰FCC催化剂可改善其表面的弱L酸分布,增强催化剂对噻吩类硫化物的选择性吸附能力,提高FCC催化剂脱除噻吩类硫化物性能。氧化钒作为典型的L酸碱对化合物,利用其修饰FCC催化剂可改善裂化催化剂的脱硫活性。鉴于氧化钒对FCC催化剂的活性组分分子筛存在一定的破坏作用,FCC催化剂的载体是较适宜的修饰位置。低价态钒较高价态钒对噻吩有着更强的化学吸附能力,因而采用还原预处理后的催化剂可得到较好的脱硫效果。     

FCC轻汽油中C5烯烃临氢反应宏观动力学研究

在压力0.5~2.0 MPa、反应温度313~413 K、液体空速2.5~30 h?1的范围内,在管式滴流床反应器中,对C5烯烃在Ni/Al2 O3催化剂上的临氢反应进行了宏观动力学研究.结果表明,C5直链烯烃加氢反应对烯烃的反应级数为1,对氢压的级数为2.16,加氢活化能为21.11 kJ?mol?1;戊烯-1、3-甲基-1-丁烯、2-甲基-1-丁烯双键异构反应对烯烃的反应级数都为1,异构活化能依次为27.6、42.24、79.62 kJ?mol?1.表明了在相同条件下,烯烃加氢反应速率大于异构化反应速率,C5支链烯烃比直链烯烃更难异构.通过对实验数据的拟合得到反应动力学参数和动力学方程,对方程的检验表明,计算值与实验值吻合较好,误差基本在10%以内,表明在实验条件范围内,模型具有较高的可信度,可用于反应过程模拟和反应器的设计.     

催化裂化催化剂碱氮中毒数学模型的研究

利用几种催化剂的催化裂化反应试验数据,通过碱氮中毒模型方程推导和模型参数的估计,建立了评价裂化催化剂抗碱氮中毒活性稳定性的数学模型。关联研究结果表明,降低催化剂分子筛含量和稀土金属含量,以及提高硅铝比和钠含量,有利于提高催化剂抗碱氮中毒活性稳定性;提高催化剂分子筛含量、硅铝重量比、稀土金属含量,以及降低钠含量,可提高催化裂化反应速率。     

Synergetic effects of Y-zeolite and amorphous silica-alumina as main FCC catalyst components on triisopropylbenzene cracking and coke formation

The synergetic effects of HY-zeolite and silica-alumina (SA), as two major components of an FCC catalyst, on the cracking activity and coking tendency during catalytic cracking of 1,3,5-triisopropylbenzene (TiPB, as a resid representative) were studied. NaY-zeolite and SA were synthesized by hydrothermal and co-precipitation methods, respectively, and ammonium exchanged for three times at 80 °C. The catalysts were characterized by XRD, XRF, SEM, BET, AAS and ammonia TPD techniques. TiPB cracking was investigated on four different catalyst configurations including SA, Y-zeolite, SA.Y and SA-Y in a fixed bed reactor. SA.Y stands for physical mixture of equal amounts of Y-zeolite and SA. For SA-Y, a bed of SA was placed upstream of the same amount of Y-zeolite. The catalysts were in-situ activated at 475 °C and evaluated by TiPB cracking at 350 °C. The coke content of the catalyst beds, after 40 min cracking of TiPB, was estimated by TPO using an FT-IR gas cell. At 3 min time on stream, 5.2 times higher yield of benzene, as a deep cracking product, is observed on SA-Y as compared to SA.Y. The TiPB conversion decreases in the order of SA-Y > SA.Y > Y-zeolite ? SA. Furthermore, as compared to Y-zeolite, 24% lower coke is formed on SA-Y. Also CO evolution during TPO of coked SA-Y catalyst is about 24% lower than that of the coked zeolite. As a result, protecting of Y-zeolite by SA from direct exposure to resid feed enhances the cracking activity, decreases the tendency to coke formation and diminishes CO emission in the catalyst regeneration process.     

钒催化剂生产过程中微波煅烧实验与性能研究

采用微波煅烧法生产钒催化剂 ,并对其性能进行了考察。结果表明 ,与传统方法生产的钒催化剂相比 ,微波煅烧钒催化剂的比表面、机械强度、磨耗等指标均有提高