燕山碳五分离装置异戊二烯损失率高原因分析

裂解碳五馏分中富含大量双烯烃,其中异戊二烯(IP)作为生产多种橡胶的原料,具有较高的利用价值。燕山碳五分离装置采用二甲基甲酰胺(DMF)萃取精馏法,生产聚合级异戊二烯,装置设计IP损失率为9%,但在实际上产中,IP损失率高达30%。碳五双烯烃容易发生聚和反应,因此主要从聚合反应和轻组分采出两方面,分析IP损失率高的原因。结果显示,溶剂含水量高、亚硝酸钠含量低、低负荷下热二聚反应停留时间长等因素导致的IP聚合反应损失,占IP损失量的50%;物料过量返回引起的预脱轻塔和第一萃取塔塔顶轻组分采出损失,分别占IP损失量的37%和13%。双烯烃聚合反应直接影响装置的平稳运行,聚合反应不但会引起IP聚合损失,也会造成萃取单元再沸器加热能力变差,烃类不能与溶剂完全分离,进一步导致装置内返回量超标,预脱轻塔进料中IP组分浓度从17%提高至28%,调整不当会使轻组分中IP含量超标。因此,控制双烯烃聚合是降低IP产品损失率的关键。     

聚丙烯聚合反应机理研究与流程模拟

聚丙烯由于其优异的热性能和机械性能,已成为最重要的热塑性产品之一,国内外聚丙烯产能迅速增长.中国石化(SINOPEC)共有35套聚丙烯生产装置,分布在24个炼化生产企业,总生产能力达到404×104t/a,可生产聚丙烯均聚物、共聚物、抗冲共聚物等产品.应用流程模拟技术建立的聚丙烯装置模型,可用于工程师研究聚合物产量和质量与聚合物密度、熔体流动速率、等规度等聚合物属性同各操作条件之间的关系,从而优化操作,特别是聚合反应参数,提高产品产量和质量.探讨了聚丙烯聚合过程反应机理,并应用美国AspenTech公司的Aspen Polymers Plus软件,对聚丙烯聚合过程进行模拟,通过调整聚合反应动力学参数,如活化能和指前因子,模拟每个牌号的熔融指数、等规度、每个活性中心上的产量、数均分子量、重均分子量,模拟误差可控制在4％以内,模型能够准确反映聚合反应动力学机理,应用模型,可以指导聚丙烯装置操作的优化、产品牌号的切换,实现装置节能降耗、挖潜增效.     

煤制烯烃合成低黏度聚α-烯烃基础油工艺研究

以煤制烯烃的145～2300C馏分段为原料,采用二甲亚砜为溶剂,进行精制处理,将精制后的烯烃原料以AlCl3为催化剂、正辛烷为溶剂,采用溶剂聚合方式,合成润滑油基础油。实验分别考察了温度、反应时间和催化剂比例等对聚合反应的影响。结果表明,在催化剂比例为2．25％、反应时间为2h、反应温度为110℃的条件下,基础油（PAO）收率可达84．36％,其100℃时运动黏度为8．606mm2／s,黏度指数达到147,闪点和倾点分别为237℃与-55℃。分别对以煤制烯烃为原料,与传统纯烯烃（1-癸烯）为原料的两种聚α-烯烃基础油的收率和主要性能进行比较,结果表明,煤制烯烃聚合物除收率及闪点较低外,其他性能指标均与1-癸烯为原料相当,因此,煤制烯烃可作为合成低黏度聚α-烯烃（PAO）基础油的替代原料。研究结果可为以煤制烯烃为原料合成润滑油基础油提供指导。     

Electrolysis of waste water containing aniline to produce polyaniline and hydrogen with low energy consumption

Hydrogen generation from water electrolysis is attempted to be one of the replacement of sources as a clean fuel with high energy density. However, its application is limited by the high overpotential of oxygen evolution reaction (OER). Herein, hydrogen fuel is obtained from waste water by replacing OER with aniline electrochemical polymerization. Compared to the OER, the potential of aniline electro-polymerization greatly decreases 1240 mV at the current density of 30 mA cm⁻² even using carbon paper electrode. Moreover, the Faradaic efficiency of hydrogen production is close to 100%. The as-prepared polyaniline demonstrates good performance as electrochemical capitative materials. This work provides efficient and lower energy consumed access to co-generate hydrogen and polyaniline in a convenient step by starting from the toxic and environmental-unfriendly wastewater.     

基于小波神经网络的聚丙烯熔融指数预测研究

准确地预测聚丙烯的产品质量,对加强产品质量的控制和节省能源,具有十分重要的现实意义。聚丙烯产品质量的控制,是受反应时间和升温速率等多因素共同影响的非线性问题。本文模型将聚丙烯聚合前期的升温速率或釜内压力变化速率,作为神经网络输入参数,研究了聚合前期温度（压力）与熔融指数的关系。仿真结果表明,建立的小波神经网络网络模型推广能力好,效果比较令人满意,将为下一步对生产装置的改造和控制提供指导。     

Investigation of mixing mechanisms and energy balance in reactive extrusion using three-dimensional numerical simulation method

The polymerization of ε-caprolactone in fully-filled conveying elements of co-rotating twin-screw extruders was analyzed with three-dimensional numerical simulation method. The effects of screw rotational speed, geometry of screw element, and initial conversion at the channel inlet on polymerization progression were studied. The simulation results show that polymerization is accelerated with increasing screw pitch, due to the increase in mixing intensity. With increasing screw rotational speed, the reaction could either slow down or speed up, depending on the viscosity of the reaction system. It is found that the advancement of polymerization depends on the competition among heat from reaction, viscous dissipation and heat loss through the wall surfaces.     

The effects of hyperbranched poly(siloxysilane)s on conductive polymer aluminum solid electrolytic capacitors

An aluminum solid electrolytic capacitor, using poly-(3,4-ethylenedioxythiophene) (PEDOT) as a counter electrode, was prepared with hyperbranched poly(siloxysilane)s (HBPSi) that has a large number of vinyl groups to improve the interfacial properties between aluminum oxide and PEDOT. Capacitance and equivalent series resistance (Rs) were significantly improved compared to untreated oxide film and vinyl terminated polydimethylsiloxane coated interfaces. From electrochemical measurement of the withstand voltage, damage to the oxide film from chemical polymerization of PEDOT was less with the HBPSi treatment. Frequency characteristics and electrical conductivity measurements of the polymer indicated that the resistance inside the etched porous layer was greatly reduced. These results show that the HBPSi pre-coating layer inhibited degradation of the oxide film by chemical polymerization of PEDOT and the conductivity of PEDOT in the etched porous oxide layer, and also enlarges the contact area by improving interfacial adhesion.     

Microencapsulation of n‐hexadecanol by in situ polymerization of melamine–formaldehyde resin in emulsion stabilized by styrene–maleic anhydride copolymer

Microcapsules with high thermal energy storage density were synthesized by in situ polymerization using melamine–formaldehyde resin as shell and n‐hexadecanol as core. Styrene–maleic anhydride (SMA) copolymer was synthesized by solution polymerization and hydrolyzed by NaOH to enhance its water solubility. This negatively charged SMA molecular copolymer self‐assembles on the surface of n‐hexadecanol droplets and facilitates the precipitation of positively charged melamine–formaldehyde prepolymer onto the droplet surface electrostatically. The morphology, chemical structure, composition, and thermal properties were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, and gas chromatography, respectively. The results show that the obtained microencapsulated phase‐change material (MePCM) dispersed individually with a spherical shape. Amount of emulsifier, ratio of shell–core material, and pH value of solution have a significant effect on the microencapsulation. Under optimum condition of 8% SMA to core material, 3.3:10 of shell–core material in feed, and polymerization under pH 4.0, spherical n‐hexadecanol MePCMs with core content of 79.1% and melting enthalpy of 171 J g^?1 at around 51°C were prepared. In situ polymerization based on SMA‐stabilized emulsion opens up a route to prepare a variety of microcapsules with aliphatic alcohol as core material. Copyright © 2014 John Wiley & Sons, Ltd.     

The importance of heat evolution during the overcharge process and the protection mechanism of electrolyte additives for prismatic lithium ion batteries

In this work, the rate of heat generation in the overcharge period for 103450 prismatic lithium ion batteries (LIBs) of the LiCoO₂–graphite jellyroll type with a basic electrolyte consisting of 1 M LiPF₆–PC/EC/EMC (1/3/5 in weight ratio) has been found to be more important than the gas evolution which was traditionally considered as the main reason in the overcharge protection mechanism. The cell voltage, charge current, and skin temperature were monitored during the charge process. For a single battery or batteries in parallel, LIBs without any additives is an acceptable design if the cell voltage is not charged above 4.55 V under the common charge program. The rate of heat generation from the polymerization of 3 wt% cyclohexyl benzene (CHB) is high enough to cause the explosion or thermal runaway of a battery, which is not found for an LIB containing 2 wt% CHB + 1 wt% tert-amyl benzene (TAB). In the 12 V overcharge test at 1C, the thermal fuse was broken by the high skin temperature (ca. 80 °C) due to the polymerization of 3 wt% CHB, which was also the case for LIBs containing 2 wt% CHB + 1 wt% TAB. The disconnection of the thermal fuse, however, did not interrupt the thermal runaway of LIBs without any additives because the battery voltage was too high (ca. 4.9 V). The influence of specific surface area of active materials in the anode on the polymerization kinetics of additives has to be carefully considered in order to add correct amount of overcharge protection agents.     

Morphology, structure and thermal stability of microencapsulated phase change material with copolymer shell

A series of microencapsulated phase change materials (MicroPCMs) with n-octadecane as core were successfully fabricated by suspension-like polymerization. The influence of initiator type and polymerization temperature on MicroPCMs were investigated systemically. The morphology of these microcapsules with different copolymer shells and various phase changing material (PCM) contents were observed by scanning electron microscopy (SEM). In addition, the core-shell structure and the shell thickness of microcapsules were also characterized by SEM. Thermal gravimetric analysis (TGA) curves indicate that the effects of different copolymer shell and various PCM contents on thermal stability of MicroPCMs were insignificant. Besides, SEM micrographs show that all of the MicroPCMs with various PCM contents remained intact after heat treatment at 200 °C for 30 min, however, all of the heat-treated MicroPCMs had no enthalpy as demonstrated by differential scanning calorimetry (DSC) curves. From above results, the weight loss of MicroPCMs may be caused by the penetration of decomposed gas of n-octadecane through the intact shells.     

聚丙烯装置用氢优化及改造措施

介绍了中国石油大连石化公司有机合成厂化二车间为降低7×10^4t／a聚丙烯装置成本，将化一车间重整氢提纯装置多余的氢气作为其聚合反应原料所进行的项目改造。列出了项目改造后进行的试车方案和投用方案。项目改造完成投用后，装置氢调敏感性和催化剂消耗基本与使用电解氢相当，每年在原料氢的供应方面可节约成本约1067247元。     

Sweet sorghum: A quality raw material for the manufacturing of chemical paper pulp

After the extraction of sugar in conditions adaptable to the industrial scale, sweet sorghum bagasse is used for the first time to manufacture chemical pulp. The quality of the pulp obtained is excellent for the paper industry. The pulp exhibits a degree of cohesion higher than 80%, a low kappa number indicating a good delignification, a high degree of polymerization, and exceptional physico-mechanical properties. Unexpectedly, the final results allow us to consider sweet sorghum as a major raw material for the paper industry in every region where it will be possible to grow it in association with sugar cane. These pulps can be used in sectors usually restricted to superior chemical pulps such as those obtained from softwood.     

Tar removal on dolomite and steam reforming catalyst: Benzene,toluene and xylene reforming

Tar removal performance of dolomite and commercial precious metal based steam reforming catalyst have been investigated by using the surrogated compounds of tar, namely benzene, toluene and xylene at changing tar loads and temperatures. Hydro- and steam dealkylation of alkyl aromatic hydrocarbons have been observed on dolomite and precious metal based catalyst. Gaseous products like H₂ and CO₂, started to be measured at 563 °C, and detection of benzene and toluene in case of xylene reforming proved the presence of selective reforming reaction on alkyl groups. Total steam reforming of aromatic rings has not been observed as sub-stoichiometric formation of reforming products meaning that selective steam reforming was only applied onto the alkyl groups of aromatics. Steam dealkylation reaction favorably occurred at 500–600 °C whereas thermal degradation and/or polymerization of aromatic compounds became the prevailing reaction with increasing the operation temperatures beyond 700 °C. Tar conversion was found to be independent on inlet tar load unless excess steam was present. Co-existence of tar and methane seemed beneficial as proved by enhanced methane reforming activity and complete tar removal. This improvement has been explained by the polymerization reaction of tar compounds and formation of unmeasurable soot particles.     

多锂引发剂合成星形S-SBR

星形S-SBR可以满足轮胎耐低温性能、抗湿滑性能和低滚动阻力等多种要求,并能改善S-SBR的加工性能和抗冷流性能。在5L反应釜上研究了多锂引发剂合成星形S-SBR的工艺,探讨了转化率、微观结构、共聚组成随反应时间变化关系,得到的产物不含苯乙烯微嵌段,结合苯乙烯含量24.2%,乙烯基含量45.99%,并具有良好的力学性能。200L试验结果表明:符合5L聚合实验结果,聚合工艺简单,适合工业化生产。     

Preparation and properties of solid-solid phase change materials based on polyethylene glycol and EPDM cross-linked resin containing cyclodextrin cavity

β-cyclodextrin with vinyl group (β-CD-MA) was synthesized from β-cyclodextrin (β-CD) and glycidyl methacrylate and identified by FT-IR and ¹H-NMR spectroscopy analysis. A novel adsorption resin containing cyclodextrin cavity moieties was prepared by suspension polymerization technique with ethylene-propylene-diene (EPDM), styrene (St) and β-CD-MA as comonomers in this study. The adsorption resin was used as a solid skeleton for adsorption of phase change material such as polyethylene glycol (PEG) to prepare solid-solid phase change materials (SSPCMs). Structure and phase change behaviors of SSPCMs were studied by FT-IR and DSC, and the phase change process of the SSPCM was observed by using reflection mode of POM. The experimental results showed that the introduction of cyclodextrin cavity structure increased the adsorption capacity of PEG and improved the phase change latent heat of SSPCMs. Otherwise, during the whole process of phase change, the surface morphology of SSPCMs could be observed and appeared bright or dark change. During the transition, the whole PCMs remained in solid state.     

Synthesis of nanocrystalline ZnO powder via sol-gel route for dye-sensitized solar cells

This paper reports the growth mechanism of sol-gel-derived nanocrystalline ZnO powder. The influence of pH value of the sol on the crystallite size, morphology and structure of ZnO powder was investigated by using X-ray diffraction, transmission and scanning electron microscopy. Maximum size nanocrystallite (∼14 nm) of ZnO powder was obtained for pH value of 9. An increase in the band gap (blue shift) was observed with decrease in the size of the ZnO nanocrystallites. The variation in band gap was found to be in agreement with theoretical calculations using effective mass model. The growth mechanism of ZnO particles from zinc acetate dihydrate precursor by the sol-gel process has been discussed in terms of solvation, hydrolysis and polymerization. The synthesized ZnO powders were successfully used as the electrode material for dye-sensitized solar cells.     

Characteristics of aluminium solid electrolytic capacitors using a conducting polymer

In order to form an electrochemically polymerized polypyrrole film on an electrically insulated dielectric layer surface, a conductive precoating layer was first deposited, at the expense of electrical conductivity. Using the precoating layer as the anode, a polypyrrole layer was then deposited electrochemically in preparation for the fabrication of a solid electrolytic capacitor in which the composite conducting polymer layer was used as a solid electrolyte. Soluble polyaniline could be used as a conductive precoating layer as well as polypyrrole formed by chemical oxidizing polymerization. The capacitor using the composite solid electrolyte presented excellent impedance frequency and temperature characteristics; moreover, the solid electrolyte showed ‘self-healing’ and non-polar behaviour.     

由1,4-环己烷二甲醇制备改性共聚酯的研究

以催化剂A、B、C、D和磷为催化—稳定体系,采用PTA法进行了由1,4-环己烷二甲醇改性的共聚酯聚合工艺研究,并对制备的产品进行了注塑实验和性能测试。实验表明:共聚酯聚合工艺受催化剂种类和用量、稳定剂用量、总醇与酸的物质的量比、聚合温度等条件影响;共聚酯注塑样品的物理和机械性能指标受1,4-环己烷二甲醇加量影响。     

聚合度对生物质多糖醇解影响研究

通过生物质醇解制备液体燃料与化学品获得广泛关注,但该方法存在产物复杂、选择性低、反应机理不清等问题.本文主要研究具有不同聚合度的糖类在乙醇溶剂中的反应特性.结果表明:随着温度的升高,葡萄糖、蔗糖、纤维二糖的转化率提高,转化率大小均为葡萄糖>蔗糖>纤维二糖>纤维素;在160～200℃,葡萄糖主要生成5-羟甲基糠醛,纤维二...     

Tuning the surface hydrophilicity of a C3N4 nanosheet for efficient photocatalytic H2 evolution coupled with microplastic degradation

Simultaneously realizing highly-efficient degradation of microplastics coupled with H₂ evolution is urgently demanded to solve the white pollution and energy shortage issues. Herein, we fabricate a series of fragmented hydrophilic homogeneous carbon nitride (TP-PCN) by terminating the polymerization of carbon nitride using iodide ions (I⁻), which acts as an invisible inhibitor by breaking the π-π bond to reduce the accumulation of ultra-thin layers in PCN to inhibit the polymerization. The H₂ evolution rate of resultant photocatalyst could reach 600.3 μmol g⁻¹ h⁻¹ in alkaline polyethylene terephthalate (PET) solution, exhibiting outstanding photocatalytic activity. Meanwhile, the PET was also degraded into small molecules, which were used in agricultural production, food processing and pharmaceuticals. The high photocatalytic activity of the TP-PCN photocatalyst can be ascribed to the promoted hydrophilicity and charge separation ability. This work supplies new insights for the design of functional photocatalysts and developing green technologies to solve environment pollution.