电伴热在改质沥青工艺管线上的应用

1改质沥青工艺概况我公司1999年投产了两套并联的改质沥青生产系统,既可单独生产,也可同时生产,两套改质沥青生产系统的总设计能力为10万t/a。每套改质沥青生产系统实行的是两釜串联、连续常压热聚法工艺,其工艺流程如图1。热态中温沥青从焦油二段蒸发器底部形式自流入1号反应釜,当液位达到一定高度时,热态沥青从1号反应釜底流入3号反应釜的侧上部,3号反应釜内沥青从釜底经П型液封管进入改质沥青中间槽,反应釜用焦炉煤气加热。各釜顶逸出的闪蒸油经过冷凝冷却后进入闪蒸油槽。从工艺流程图可以看出,1号反应釜底到3号反应釜上侧部、3号反应…     

炭阳极用煤沥青中间相的研究

选取热聚法、真空闪蒸法生产的煤沥青试样,全面分析了各项理化指标,重点研究了煤沥青的中间相含量及其黏度。试验结果表明,我国热聚法生产的煤沥青中间相含量高,为3.0%～6.9%,而真空闪蒸法生产的煤沥青几乎不含中间相。热聚法生产的煤沥青中主要指标甲苯不溶物、喹啉不溶物含量也较高,比国际上普遍采用的真空闪蒸法生产的煤沥青高出20%左右。煤沥青中喹啉不溶物及中间相的含量对黏度产生很大影响。在较低的温度条件下,我国热聚法煤沥青的黏度明显高于真空闪蒸法煤沥青。煤沥青的这些性质将对炭阳极的生产工艺参数及质量带来一定的影响。     

一种管式炉加热中温沥青生产改质沥青的新工艺

介绍了采用管式炉加热中温沥青生产改质沥青的工艺,并将此新工艺与传统工艺进行了对比,主要包括产品性能、设计特点及控制方式。经过比较,新工艺有诸多优点,能够实现改质沥青的连续生产,并提高改质沥青的软化点。     

中温改质沥青生产工艺的探讨

通过实验研究了中温沥青的聚合性能。在实际生产中采用聚合法,合理控制中温沥青的反应温度、聚合时间、真空度,生产出各种中温改质沥青。     

改质沥青中间槽液下泵的变频调速

我厂于 1998年投产的改质沥青装置采用釜式连续常压热聚法,中温沥青装入反应釜后,在搅拌下加热而生成改质沥青,其生产工艺见图 1.……     

单釜流程生产改质沥青的试验与教训

改质沥青是煤焦油沥青经过热聚合处理后，组分发生变化而形成的优质沥青，多用于制造电极粘结剂。我厂原设计为两釜串联连续生产流程，因受投资控制，原设计中的2号反应釜及闪蒸油槽缓建。我们结合焦油车间的实际沥青产量，对原设计作了部分调整，变为单釜流程生产改质沥青，现生产流程如图1。     

改质沥青质量问题与工艺改进

本文对武钢改质沥青BI和QI偏低的问题进行了分析,找出了影响改质沥青质量的原因并进行了实验室模拟实验和试生产。针对所存在的问题,采取了添加闪蒸油等措施,提高了现有改质沥青生产设备对中温沥青原料的适应范围,中间槽改质沥青的温度下降,使生产安全性大大提高,产品质量更加符合国家标准。     

浅谈导热油的应用

1引言炭与石墨制品生产中，沥青的熔化与骨料的预热及糊料混提，都采用直接或间接的蒸汽和电加热。而这种加热方式仅仅限于以中温沥育作为粘合剂，如果采用品质特性良好的高温改质沥青，就必须改变加热设备或传递介质。1980年贵州铝厂从日本引进了8万吨电解铝生产技术，其中阳极生产配料中使用高软化点的改质沥青，混捏糊料中的加热方式采用了西德惠尔斯公司生产的Marlothcrm－s热媒体导热油，这样解决了高温或改质沥青使用中的加热问题。我国导热油早期在食品、纺织、制药、制漆等轻工业系统及物料的加热、烘干、脱水、化合与分解工序中应…     

适用于连续减压法生产改质沥青的感应加热炉电源设计

为改善改质沥青生产工艺及提高改质沥青产品质量,针对连续减压法生产改质沥青工艺,设计了一套感应加热炉装置。本文详细介绍了感应加热炉的电源部分的系统原理结构、设计思路和相关参数计算。     

煤沥青深加工工艺与粘结剂的性能

通过对真空闪蒸法和常压热聚合法等粘结剂沥青生产工艺的评价,讨论了作粘结剂用的煤沥青性能及基对碳素制品质量的影响,提出了生产粘结剂沥青工艺的设想。     

环氧脂肪酸甲酯连续闪蒸脱水脱味精制工艺研究

环氧脂肪酸甲酯是以脂肪酸甲酯为原料制备的新型环保增塑剂。传统的生产工艺中,采用减压蒸馏制得的产品酸值、环氧值、色泽、气味、加热减量等指标不够理想。采用连续闪蒸脱水脱味精制工艺,制备的产品其加热减量≤0.30%,色泽≤100号(Pt-Co法),基本无味,达到了生产高品质浅色无味的环氧脂肪酸甲酯的目的。     

碳酸钾生产中吹脱除氨新工艺实验研究

在离子交换法生产碳酸钾的基础上,将原有蒸发除氨工艺改为真空加热吹脱除氨工艺.进行了常压加热除氨、真空加热除氨、常压加热吹脱除氨和真空加热吹脱除氨4种工艺方法的实验研究和比较.结果表明,在实验条件下离子交换液的温度、蒸氨时间、气相压力和吹脱气量等对铵离子的分解率有很大影响.真空加热吹脱除氨效果显著.     

Synthesis and characterization of poly(allyl methacrylate) obtained by γ‐radiation

Allyl methacrylate was polymerized by γ‐radiation under vacuum in solution and atom transfer radical polymerization (ATRP) methods and also in the presence of atmospheric oxygen in bulk. The kinetic curve is S‐type with a longer induction period, because of the presence of oxygen, in bulk polymerization. The curve for the solution polymerization is almost linear with a short induction period. The rate started to decrease after about 60% conversion and reached to a limiting conversion of 100%. The polymerization by ARTP method using γ‐radiation as initiator instead of conventional heating method gave a kinetic curve of linear character up to about limiting conversion of 100%. The polymers obtained were mostly gel type with linear chain fractions at lower conversions. The polymer characterizations were carried out by FTIR, differential scanning calorimetry, NMR, TGA, and XRD methods. The polymers were shown to proceed by the opening of vinyl groups. The allyl groups caused a limiting crosslinking, but 98–99% of the allyl groups are shown by FTIR and NMR, unchanged during the polymerization. The cyclic type polymer formation was not likely taking place. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1076–1083, 2007     

Mathematical modelling of lignin pyrolysis

Seven lignins from different sources were pyrolysed (i) isothermally in vacuum over the temperature range 300–1300 °C and (ii) at a constant heating rate of 30 °C min^?1 and a pressure of 0.1 MPa over the temperature range 150–900 °C. The mass fraction of each product—char, tar and gas species—and the elemental composition of the char and the tar were determined for the flash pyrolysis experiments. The evolution rates of the gas species and the tar versus the dynamic temperature of pyrolysis were determined for the constant heating rate pyrolysis experiments. Although the amount of each product species varied from lignin to lignin, the evolution rates were insensitive to the lignin source and the extraction process. To model the data, modifications were made to a recently developed model of coal pyrolysis. The model proved to be successful in simulating both the data from vacuum flash pyrolysis and constant heating rate pyrolysis of Iotech lignin.     

间歇式本体法PP装置闪蒸釜氮气连续汽提工艺研究

在间歇式本体法聚丙烯(PP)装置上研究了闪蒸釜氮气置换工艺,分析测试了闪蒸釜反复抽真空充压工艺和闪蒸釜连续汽提工艺在置换效果、氮气耗量、排人气柜氯气量、携带粉料量、置换时间等.结果表明:与反复抽真空充压工艺相比,闪蒸釜连续汽提工艺能够明显降低间歇式本体法PP装置的丙烯单耗、氮气消耗和污染物排放.     

Development of real-time state estimators for reaction–separation processes: A continuous flash fermentation as a study case

The development of reliable on-line state estimators applicable to reaction–separation processes is addressed in this work. Artificial Neural Network-based software sensors (ANN-SS) are proposed to allow on-line measurement of key variables, with an estimation algorithm that uses secondary variables as inputs. A continuous laboratory-scale flash fermentation for bioethanol production is considered as a case study. The process consists of three interconnected units: fermentor, filter (tangential microfiltration for cell recycling) and vacuum flash vessel (for the continuous separation of ethanol from the broth). The concentrations of ethanol in the fermentor and of ethanol condensed from the flash are successfully monitored on-line using ANN-SS. The proposed model contributes to improve the understanding of the complex relationships between process variables in the reaction and separation units, which is of major importance to allow the operation of the ethanol production process near its optimum performance.     

Solid-state polymerization of poly(ethylene terephthalate)

Solid -state polymerization of poly(ethylene terephthalate) (PET) is carried out by heating the low molecular weight prepolymer at temperatures below its melting point but above its glass transition temperature. Postcondensation occurs and the condensation byproducts can be removed by applying vacuum or inert gas. Polymers obtained usually have high molecular weight, low carboxyl and acetaldehyde content, and can be used for beverage bottle or industrial yarns. Polyesters for textile purposes are manufactured by a melt process. Chemical reactions involved in the solid state polymerization are transesterification, esterification, as well as the diffusion of byproducts. Overall reaction rate was governed by the molecular weight, carboxyl content of prepolymer, crystallinity, particle size, reaction temperature, and time. Prepolymer for solid state polymerization should have intrinsic viscosity 0.4 dL/g or more, density 1.38 g/mL, and minimum dimension 3 mm or less. The reaction temperature could be 200–250°C. When textile grade PET is used as prepolymer, crystallization at 180–190°C for 1–2 h increases the density to 1.38 g/mL. Polymerization at 240–245°C for 3–5 h can raise the intrinsic viscosity to 0.72 dL/g and carboxyl content less than 20 meq/kg. Appropriate reaction conditions are subject to the properties of prepolymers and the design of reactors. Reactor used for solid state polymerization could be vacuum dryer type or stationary bed. The former is suitable for a small capacity and is run batchwise. The latter is a continuous process and is economically feasible for large -scale production.     

Microwave‐irradiated ring‐opening polymerization of D,L‐lactide under atmosphere

Poly(D ,L ‐lactide) (PDLLA) was synthesized by microwave‐irradiated ring‐opening polymerization catalyzed by stannous octoate (Sn(Oct)₂) under atmosphere. The effects of heating medium, monomer purity, catalyst concentration, microwave irradiation time, and vacuum level were discussed. Under the appropriate conditions such as carborundum (SiC) as heating‐medium, 0.15% catalyst, lactide with purity above 99.9%, 450 W microwave power, 30 min irradiation time, and atmosphere, PDLLA with a viscosity–average molecular weight (M_η) over 2.0 × 10⁵ and a yield over 85% was obtained. The dismission of vacuum to ring‐opening polymerization of D ,L ‐lactide (DLLA) under microwave irradiation simplified the process greatly. The temperature under microwave irradiation and conventional heating was compared. The largely enhanced ring‐opening polymerization rate of DLLA under microwave irradiation was the coeffect of thermal effects and microwave effects. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2244–2247, 2006     

Sintering behavior of 8YSZ-Ni cermet: Comparison between conventional,FST/SPS,and flash sintering

Cermets are ceramic metal composites. The metallic phase in the cermet typically undergoes oxidation during sintering in air. Electric field-assisted sintering processes such as field-assisted sintering technology/spark plasma sintering (FAST/SPS) and flash involves very high heating rates, short processing time and low processing temperature. The main aim of this work was to see if field-assisted sintering techniques can prevent the oxidation of the metallic phase in the cermet. Sintering behavior of 8YSZ-5 wt.% Ni cermet was studied by three different techniques namely; conventional sintering, FAST/SPS and flash sintering. Phases and microstructure were analyzed through X-ray diffraction and scanning electron microscopy, respectively. Temperature and time required for sintering the samples via FAST/SPS and flash sintering was significantly lower than that during conventional sintering. In addition, we found limited grain growth during FAST/SPS and flash sintering. During conventional sintering in reducing atmosphere (Ar and vacuum), Ni particles retained their elemental state, however the extent of densification was poor in the cermet. FAST/SPS in argon and vacuum resulted in almost complete densification (relative density > 97%) and Ni particles were retained in their elemental state in the cermet. During flash sintering in air, the samples sintered to a high densification (relative density ∼98%), however, Ni particles were completely oxidized.     

间歇式液相本体法聚丙烯闪蒸操作分析

通过对常压闪蒸和真空闪蒸2个过程的分析,说明在聚丙烯生产中,采用真空闪蒸可以降低丙烯消耗,并对实现真空闪蒸需解决的问题提出建议。