高密度催化剂R-264在连续重整装置的应用

本装置是设计规模为200万吨/年的重整装置,2017年,再生单元催化剂由标准密度重整催化剂R-234更换为高密度的重整催化剂R-264,本文主要对两种催化剂的结构性能,装填量等参数进行了对比。对新催化剂的工艺性能标定情况进行了分析,归纳了装置出现的问题:再生热停车时,分离料斗氯吸附区出口温度高;待生催化剂积碳速率变快,碳含量偏高。分析了产生上述问题的原因。为其它装置推广应用R-264提供了宝贵经验。     

国产PS-Ⅵ连续重整催化剂在湛江东兴石油企业有限公司的工业应用

湛江东兴石油企业有限公司于2005年3月建成投产的50万吨／年的连续重整装置采用的是UOP的第三代重整专利技术,催化剂则选择了国产PS—VI连续重整催化剂。开工运转和标定结果表明PS—VI催化剂具有积碳速率低、选择性高、持氯能力强、活性稳定性好等特点。     

重整装置进料换热器的选择

随着装置规模的扩大,需要对一些重要的大型设备进行正确的选型。重整进料换热器是重整装置中的重要设备,重整进料换热器对于降低整个重整装置反应系统的压降起着重要作用。着重介绍了立式管壳式重整进料换热器和Pack inox焊接板式换热器的结构及特点,并提出了在连续重整装置中重整进料换热器的选择方案     

国产连续重整技术在装置改造中的应用探讨

介绍了国内开发的连续重整工艺和具有连续重整特点的低压组合床工艺,其独特的LPEC催化剂连续再生技术在国内半再生重整装置和第一代连续重整装置的改造中具有一定的应用前途.对中国石化洛阳分公司连续重整装置采用LPEC催化剂连续再生技术扩能改造进行了探讨分析,认为改造技术先进、可靠,装置设备利旧率达到了76.8%,具有良好的经济和社会效益.     

RC011连续重整催化剂的工业试生产

石油化工科学研究院研制的一种新型连续重整催化剂PS Ⅵ（研究型号），具有低积炭速率和高选择性，适用于各种类型新建连续重整装置，特别适用于受再生能力限制的连续重整装置的扩能改造。2000年11月在建长公司化工厂进行了PS Ⅵ型连续重整催化剂的吨级工业放大试验, 得到了吨级放大的RC011（生产型号）催化剂成品，取得了工业放大的成功。     

连续重整催化剂提升管道设计探讨

石化连续重整装置反应部分催化剂采用含有铂的催化剂,催化剂的再生是重整装置的核心部分。催化剂提升管道为气固输送过程,输送过程的压降、催化剂和弯管的磨损是管道设计优劣的两个重要指标。结合长庆重整装置,通过分析立管、斜管和弯管处的压降,研究催化剂与弯管磨损的主要影响因素,对重整催化剂提升管管道设计提出合理建议。     

重整再生气脱氯剂的选择与应用

针对困扰重整装置催化剂再生后活性不稳定的问题,对原装置进行了技改,采用固体脱氯剂代替原来的碱洗来处理重整催化剂再生气,使再生系统达到平稳良好的运行状态。本技改措施的关键是要选择优良的高温脱氯剂。     

连续重整装置设计参数的选择

揭示了连续重整的反应温度、压力、空速、氢油比、催化剂循环速率的相互关系,以及催化剂、原料和产品辛烷值对这些参数的影响。通过对比现有连续重整装置的设计参数及实际运行状况,充分考虑连续重整工艺和催化剂的技术进步,对新建连续重整装置的设计参数进行了探讨。     

UOP连续重整新技术的应用

催化重整是石油炼制主要过程之一,目前国内引进的大多是UOP连续重整工艺,为满足装置规模越来越大的需要,UOP公司在设计方案中采用了一些新的技术。以泉州石化200万吨/年连续重整装置为例,重点介绍了反应器并列式布置、"梯形"扇形筒、Chlorsorb氯吸附技术、冷却模式催化剂提升系统和低流量低燃烧模式等新技术的应用。     

重整装置催化剂破碎及扇形筒损坏原因分析

对南方某炼厂320Mt/a连续重整装置反应系统催化剂破损、结焦,及扇形筒损坏的现象进行深入分析,并提出改进措施。首次开工雨天装剂、新催化剂开工升温速度过快,循环气中长期水含量超标是造成催化剂机械强度受损,以及重整反应器、再生器扇形筒选型,中心筒施工安装质量好坏都有可能导致催化剂破损。装置开工初期,再生系统长时间催化剂再生不畅,重整装置进料中硫含量、循环氢中的硫化氢含量长期低于UOP的操作指导书要求,都有可能造成催化剂结焦、结碳,导致扇形筒损坏。     

锂快离子导体Li1.4Al0.1Mg0.1Ti1.8Si0.1P2.9O12和Li1.8Al0.1Mg0.1Ti1.6Si0.3P2.9O12的合成及导电性能研究

以LiTi2(PO4)3为基,用分析纯原料经高温固相反应(850、900、950℃)制得锂快离子导体材料Li1.4A l0.1Mg0.1Ti1.8Si0.1P2.9O12(以下简称TM1)和Li1.8A l0.1Mg0.3Ti1.6Si0.1P2.9O12(以下简称TM2)。用交流阻抗技术测定了合成物的电导率。反应温度为850、900和950℃合成的TM1在298 K测定的电导率分别为1.05×10-4S/cm,1.11×10-4S/cm,1.31×10-4S/cm;同样条件下合成的TM2的电导率分别为7.41×10-5S/cm,7.81×10-5S/cm,8.11×10-5S/cm。以上数据表明,TM1和TM2的离子电导率随着合成温度的升高而增大。在373、473、573和673 K测定的离子电导率也呈上述趋势。反应温度为950℃的合成物的电导率最高,反应温度为850℃的合成物的离子电导率最低,因此,TM1和TM2的最佳合成温度为950℃。T≥100℃时,TM2的离子电导率比TM1的大。X射线衍射分析结果表明,TM1和TM2在不同的反应温度(850、900、950℃)下均得到空间群为R3c的合成物。     

Sodium 4-Phenylbutyrate Reduces Ocular Hypertension by Degrading Extracellular Matrix Deposition via Activation of MMP9

Ocular hypertension (OHT) is a serious adverse effect of the widely prescribed glucocorticoid (GC) therapy and, if left undiagnosed, it can lead to glaucoma and complete blindness. Previously, we have shown that the small chemical chaperone, sodium-4-phenylbutyrate (PBA), rescues GC-induced OHT by reducing ocular endoplasmic reticulum (ER) stress. However, the exact mechanism of how PBA rescues GC-induced OHT is not completely understood. The trabecular meshwork (TM) is a filter-like specialized contractile tissue consisting of TM cells embedded within extracellular matrix (ECM) that controls intraocular pressure (IOP) by constantly regulating aqueous humor (AH) outflow. Induction of abnormal ECM deposition in TM is a hallmark of GC-induced OHT. Here, we investigated whether PBA reduces GC-induced OHT by degrading abnormal ECM deposition in TM using mouse model of GC-induced OHT, ex vivo cultured human TM tissues and primary human TM cells. We show that topical ocular eye drops of PBA (1%) significantly lowers elevated IOP in mouse model of GC-induced OHT. Importantly, PBA prevents synthesis and deposition of GC-induced ECM in TM. We report for the first time that PBA can degrade existing abnormal ECM in normal human TM cells/tissues by inducing matrix metalloproteinase (MMP)9 expression and activity. Furthermore, inhibition of MMPs activity by chemical-inhibitor (minocycline) abrogated PBA’s effect on ECM reduction and its associated ER stress. Our study indicates a non-chaperone activity of PBA via activation of MMP9 that degrades abnormal ECM accumulation in TM.     

Preparation and characterization of chitosan based hydrogels containing cyclodextrin inclusion compounds or nanoemulsions of thyme oil

Hydrogels derived from natural polysaccharides are ideal scaffolds for use in biomedical applications. pH‐sensitive polyvinyl alcohol and chitosan hydrogels containing inclusion compounds of thyme oil (TM) with host methyl‐β‐cyclodextrin (MβCD) and hydroxypropyl‐β‐cyclodextrin (HβCD) and TM nanoemulsion (TM‐nano) were prepared via controlled, biocompatible and low cost freeze–thaw method. The structure of the hydrogels was characterized by Fourier transform IR spectroscopy and optical and scanning electron microscopy. The physicochemical properties of the hydrogels such as gel fraction, swelling ratio and tensile properties were measured. The water vapor transmission rate of the hydrogels indicated that they can maintain a moist environment over the wound bed. Encapsulation and release of antibacterial TM from the hydrogels were determined by UV spectroscopy. In all cases, hydrogels with lower amounts of TM evidenced slower and more controlled release. Different kinetic models were applied for evaluating the drug release mechanism. The antibacterial activity of the samples was studied by counting the number of both Gram‐negative and Gram‐positive bacteria surviving in a broth medium and the results proved the antibacterial activity of all prepared hydrogels. The results of an MTT (3‐(4,5‐dimethylthiazol‐2yl)‐2,5‐diphenyltetrazolium bromide) assay indicated more cell viability of TM‐nano hydrogels in comparison with those of TM‐βCD inclusion compounds. Cell attachment observations also showed great biocompatibility of TM‐nano hydrogels. The prepared hydrogels, especially those containing TM‐nano, might be used as potential wound dressings to improve the wound healing process. © 2019 Society of Chemical Industry     

A model of the lutropin/choriogonadotropin receptor: insights into the structural and functional effects of constitutively activating mutations

A model of the seven transmembrane helical domain (7-TM) of the human lutropin receptor was constructed from the 2D electron density map of bovine rhodopsin and a set of geometric parameters derived from a published analysis of 204 G-protein coupled receptor sequences. The Self-Consistent Ensemble Optimization method was applied to predict overall side chain packing. The model is consistent with the general helical packing properties expected of transmembrane proteins and suggests possible structural and functional effects of constitutively activating mutations. A tightly packed hydrophobic cluster formed between the intracellular halves of TM5 and TM6, as well as a specific H-bonding network formed between the central regions of TM6 and TM7, is proposed to be critical for stabilizing the inactive form of the receptor. The model suggests that single activating mutations perturb the specific interactions of TM6 with TM5 and TM7, either by disrupting the hydrophobic packing between TM5 and TM6, or by weakening the H- bonds between TM6 and TM7.      

蚕沙基多孔炭表面氧化改性对农药噻虫嗪吸附及缓控释影响

选用桑蚕废弃物蚕沙为炭源,通过炭化活化的方式获得了一种高比表面的中微双孔道生物炭材料SCSE,并采用不同氧化剂对其表面氧化处理以调控材料孔径和表面积对农药噻虫嗪分子的吸附作用力,以实现SCSE材料对农药噻虫嗪的缓控释,并系统研究了氧化改性后材料的比表面积、孔径和表面基团性质的变化对材料吸附噻虫嗪的热力学和动力学平衡以及噻虫嗪的释放动力学等性能的影响。结果表明：SCSE孔隙结构发达,其BET比表面和孔容分别为1290.95 m²/g和0.690 cm³/g;在室温下,该材料对噻虫嗪分子的吸附容量达到560 mg/g。噻虫嗪在四种SCSE上的释放动力学可分为快速持续释放过程和慢速释放过程两个过程,其中快速持续释放过程的释放动力学常数约是慢速释放过程的29～34倍;其中硝酸改性后的SCSE-HN对噻虫嗪的释放比例最大,释放速度最快。本实验所获得的四种SCSE材料对噻虫嗪的释放均表现出长效释放效力。按照一般农作物的需药量,该吸附剂只要按照0.5 g/（d·m²）的投入量便能很好地对农作物进行长效的虫害防治（>40 d）。     

Prediction of the 3D structure of FMRF-amide neuropeptides bound to the mouse MrgC11 GPCR and experimental validation

We report the 3D structure predicted for the mouse MrgC11 (mMrgC11) receptor by using the MembStruk computational protocol, and the predicted binding site for the F-M-R-F-NH(2) neuropeptide together with four singly chirally modified ligands. We predicted that the R-F-NH(2) part of the tetrapeptide sticks down into the protein between the transmembrane (TM) domains 3, 4, 5, and 6. The Phe (F-NH(2)) interacted favorably with Tyr110 (TM3), while the Arg makes salt bridges to Asp161 (TM4) and Asp179 (TM5). We predicted that the Met extends from the binding site, but the terminal Phe residue sticks back into an aromatic/hydrophobic site flanked by Tyr237, Leu238, Leu240, and Tyr256 (TM6), and Trp162 (TM4). We carried out subsequent mutagenesis experiments followed by intracellular calcium-release assays that demonstrated the dramatic decrease in activity for the Tyr110Ala, Asp161Ala, and Asp179Ala substitutions, which was predicted by our model. These experiments provide strong evidence that our predicted G protein-coupled receptor (GPCR) structure is sufficiently accurate to identify binding sites for selective ligands. Similar studies were made with the mMrgA1 receptor, which did not bind the R-F-NH(2) dipeptide; we explain this to be due to the increased hydrophobic character of the binding pocket in mMrgA1.     

Impact of helix irregularities on sequence alignment and homology modeling of G protein-coupled receptors

Comparison of the crystal structures of G protein-coupled receptors (GPCRs) revealed backbone irregularities in the majority of the transmembrane (TM) helices. Among these, wide (π bulge) and tight (3(10)) helical turns on TM2 and TM5 deserve special attention because of their proximity to the ligand binding site. These irregularities are related to residue insertion or deletion (reflected by inclusion of gaps in sequence alignments) accumulated during the evolution of these two helices. These findings have direct implications for the sequence alignments, phylogeny reconstruction, and homology modeling of class A GPCRs.     

Telmisartan Attenuates Kanamycin-Induced Ototoxicity in Rats

Telmisartan (TM) has been proposed to relieve inflammatory responses by modulating peroxisome proliferator activator receptor-γ (PPARγ) signaling. This study aimed to investigate the protective effects of TM on kanamycin(KM)-induced ototoxicity in rats. Forty-eight, 8-week-old female Sprague Dawley rats were divided into four groups: (1) control group, (2) TM group, (3) KM group, and (4) TM + KM group. Auditory brainstem response was measured. The histology of the cochlea was examined. The protein expression levels of angiotensin-converting enzyme 2 (ACE2), HO1, and PPARγ were measured by Western blotting. The auditory threshold shifts at 4, 8, 16, and 32 kHz were lower in the TM + KM group than in the KM group (all p < 0.05). The loss of cochlear outer hair cells and spiral ganglial cells was lower in the TM + KM group than in the KM group. The protein expression levels of ACE2, PPARγ, and HO1 were higher in the KM group than in the control group (all p < 0.05). The TM + KM group showed lower expression levels of PPARγ and HO1 than the KM group.TM protected the cochlea from KM-induced injuries in rats. TM preserved hearing levels and attenuated the increase in PPARγ and HO1 expression levels in KM-exposed rat cochleae.     

Secondary Structures of the Transmembrane Domain of SARS-CoV-2 Spike Protein in Detergent Micelles

Spike protein of SARS-CoV-2 contains a single-span transmembrane (TM) domain and plays roles in receptor binding, viral attachment and viral entry to the host cells. The TM domain of spike protein is critical for viral infectivity. Herein, the TM domain of spike protein of SARS-CoV-2 was reconstituted in detergent micelles and subjected to structural analysis using solution NMR spectroscopy. The results demonstrate that the TM domain of the protein forms a helical structure in detergent micelles. An unstructured linker is identified between the TM helix and heptapeptide repeat 2 region. The linker is due to the proline residue at position 1213. Side chains of the three tryptophan residues preceding to and within the TM helix important for the function of S-protein might adopt multiple conformations which may be critical for their function. The side chain of W1212 was shown to be exposed to solvent and the side chains of residues W1214 and W1217 are buried in micelles. Relaxation study shows that the TM helix is rigid in solution while several residues have exchanges. The secondary structure and dynamics of the TM domain in this study provide insights into the function of the TM domain of spike protein.     

Electromagnetic interference and electrical conductivity characteristics of carbon/polycyanate composite with nanostrandsTM under tensile load

Electromagnetic interference (EMI) and electrostatic discharge (ESD) shielding effectiveness of M55/RS‐3 composite (i.e., carbon fiber in a toughened polycyanate resin matrix) combined with nickel nanostrands^TM was investigated when subjected to the monotonic tensile load. These were quantified in the terms of dB attenuation and sheet resistance, respectively. A baseline panel without nanostrands^TM and three lay‐ups with different locations of nickel nanostrands^TM layers were characterized. These locations were outside surfaces, dispersed throughout the laminate thickness or the mid‐plane. The nanostrands^TM are capable of providing EMI and ESD shielding protection without any detrimental effects on the mechanical behavior of the composite (i.e., damage mechanisms and ultimate tensile strength) under the tensile loading condition. The placement of nanostrands^TM on the exterior surfaces in the composite lay‐up provided better EMI and ESD shielding effectiveness. The EMI protection capability from nanostrands^TM at any location was practically constant with increasing tensile load up to the final fracture. However, sheet resistance did not change with increasing tensile load only when nanostrands^TM were placed at the outside surfaces. The nanostrands^TM layers were not damaged until the final composite fracture. POLYM. COMPOS., 31:1343–1351, 2010. © 2009 Society of Plastics Engineers