分散剂对丙烯腈装置回收塔及四效蒸发运行周期的影响

通过在丙烯腈装置吸收塔釜液泵入口管线和一效蒸发器循环线加入分散剂,避免聚合物结垢并附着在换热器内,提高回收塔原料预热器、回收塔再沸器以及四效蒸发器的换热效果。研究结果表明,分散剂以4.64kg/h流量加入吸收塔釜液泵入口管线上,回收塔进料温度调节阀阀位由10%提高至75%,回收塔进料温度达到工艺控制指标(65℃),回收塔再沸器蒸汽消耗降低10t/h;分散剂以3.48kg/h流量加入在一效蒸发器循环线上,四效系统蒸发率由66%提高至74%。说明分散剂的加入能有效地阻止系统内聚合物聚集和累积,显著提高了换热器的换热效率,延长了装置的运行周期,降低了能耗,提高了生产效率。     

丙烯腈装置反应气体冷却器在线清堵改造

丙烯氨氧化法生产丙烯腈装置中,反应气体冷却器由于反应生成的高温反应气体中含有丙烯腈、氢氰酸、丙烯醛等易聚合的化合物,在反应气体冷却过程中容易发生聚合反应,生成的聚合物与流化床反应器带出的催化剂粉尘黏附并聚积在反应气体冷却器列管中,从而使冷却器管道阻力增加,反应系统操作压力明显升高,恶化流化床反应系统的操作状况,降低催化剂的反应性能,使装置消耗增加,运行周期缩短,影响装置的正常运行。通过试验及工业实践证明在反应气体冷却器管程入口处采用固体颗粒、以中压氮气为动力进行在线吹扫可以及时在线清除列管内壁黏附的聚合物和催化剂粉尘,实现在线清堵,延长装置的运行周期,维持装置较低的消耗水平。     

活性磷酸钙微观形貌对SAN悬浮聚合的影响

活性磷酸钙作为悬浮聚合的分散剂,在苯乙烯-丙烯腈共聚物(SAN)聚合体系中对聚合产物形貌粒径有重要影响。对活性磷酸钙(HAP)进行扫描电镜观察,发现不同来源的HAP表面形貌有较大差异。将这几种活性磷酸钙作为分散剂用于苯乙烯-丙烯腈共聚物(SAN)的悬浮聚合。对比聚合产物的粒子形貌及粒径分布,发现当HAP微观形貌为均匀竹叶形或棒状,且堆积松散时得到的聚合物粒子外观规整,粒径分布均匀。     

臭氧催化氧化工艺在丙烯腈废水深度处理中的应用

丙烯腈废水中含有大量难降解聚合物,具有一定的生物毒性,增加了废水的处理难度。本文着重介绍了臭氧催化氧化工艺在中石油大庆炼化公司丙烯腈废水深度处理中的工程应用情况。在系统运行初期,处理效果良好,出水COD去除率可达54%。但由于系统长期处于高负荷连续运行状态,使得部分催化剂板结失活,致使设备处理效率下降,COD平均去除率仅为16%。在装置进行定期反洗后,COD去除率平均为50%。     

分散剂及其在粉体研磨行业中的应用

介绍了分散剂的分散机理.着重阐述了聚合物类分散剂在重钙、高岭土等研磨行业使用中的优良性能,特别是在研磨高岭土行业,试验结果显示:与传统无机分散剂六偏磷酸钠(SHMP)相比,聚合物类分散剂有降低生产能耗、提高产能等明显优势.     

污水处理系统提标提质后调试总结

为提高污水处理装置处理水量和处理效率,对污水处理系统进行改造.改造前系统采用2套并联运行的缺氧法和好氧法(A/O法)装置,改造后系统采用2套A/O法装置串联运行,大大提高了系统的处理效率,使出水COD、氨氮质量浓度、总氮含量指标达标.     

碳纤维及无机纤维

TQ346.320061171单壁碳纳米管和丙烯腈为主的宏观纤维以及高模量纤维的制造Veedu S.T.…;US2004-180201(2004.9.16)(英)高模量宏观纤维包括单壁碳纳米管(SWNT)和丙烯腈聚合物。宏观纤维是截面尺寸≥1μm的拉伸纤维。丙烯腈聚合物-SWNT的复合纤维制造方法如下:将SWNT分散在溶剂中,如DMF或DMAc,掺混丙烯腈基聚合物,形成基本光学均匀的聚丙烯腈聚合物-SWNT浆液,将浆液纺成纤维,拉伸,干燥纤维。与没有SWNT的聚合物纤维相比较,聚丙烯腈/SWNT复合宏观纤维的模量较高,降低了收缩性。含10%SWNT的聚丙烯腈/SWNT复合纤维拉伸模量增…     

由聚丙烯腈原丝制得的活性碳纤维及其应用

1 活性碳纤维的制备 生产活性碳纤维的聚丙烯腈(PAN)原丝通常由丙烯腈、丙烯酸甲酯(MA)和衣康酸(IA)共聚而成的聚合物纺丝得到.由PAN原丝试验制备活性碳纤维(图1)有三个步骤:热氧化稳定(图2)、碳化(图3)和活化. 1.1热氧化稳定 原丝在空气或氧化气氛中、180～400℃温度范围内采用连续工艺进行热氧化稳定.在这个过程中,线形聚合物链通过腈基低聚合作用转化为可熔的梯状聚合物,在梯状聚合物的主干上形成含氧基团,如-OH,＞C=O和-COOH等,这些基团在随后的碳化过程中可以帮助梯状聚合物熔化.     

HS-172高效阻聚剂试验小结

上海石化总厂二分厂丙烯腈生产装置上使用对苯二酚(HQ)作阻聚剂,效果不够理想,常因产生聚合物而造成故障。HS-172高效阻聚剂,是一种新颖、高效、无毒的哌啶系列的氮氧游离基型阻聚剂。它用于纯丙烯腈及丙烯腈、氢氰酸混合物的阻聚试验,效果优于HQ,其结构式为     

悬浮聚合法合成交联苯乙烯-丙烯腈共聚物的研究

通过悬浮聚合实验,研究了交联剂种类、链转移剂质量分数、分散剂复配体系对合成交联聚苯乙烯-丙烯腈的悬浮聚合体系的稳定性影响。通过傅立叶变换红外光谱(FTIR)法和索式提取器来表征交联共聚物结构和测量聚合物凝胶含量。结果表明:丙烯酸酯类比二乙烯基苯交联剂更适合提高交联苯乙烯-丙烯腈合成的悬浮聚合稳定性;随着转移剂质量分数的增加,聚合稳定性上升;少量的有机分散剂聚乙烯醇与无机分散剂羟基磷酸钙复配有助于减小交联微球的粒径。     

提高丙烯腈回收率的一种新型急冷工艺和急冷塔

Quenching process and design of the quenching tower in acrylonitrile production in China were studied in order to decrease the polymerization loss of acrylonitrile in the quenching tower. Based on the research of acrylonitrile polymerization in the quenching tower, a new quenching process was proposed to avoid the disadvantages of the original process. Two kinds of internals were installed to improve the performance of the quenching tower. Through a series of air-flow and real-flow model experiments, the new quenching process and new design were showed to be successful in enhancing the mass and heat transfer in the vapor-liquid system and decreasing the loss of acrylonitrile.Industrial application showed satisfactory results of decrease of the acrylonitrile loss in the quenching tower by about 4.5% and increase of the acrylonitrile recovery of the whole plant by more than 4%.     

DMF-氯仿二元体系常压平衡数据测定与关联

采用泵式沸点仪测定了常压下DMF-氯仿二元体系在不同液相组成下的沸点,并用间接法由TPX推算了与之平衡的汽相组成;用最小二乘法求出了该系统的液相活度系数模型参数,由模型参数推算的泡点与实验值符合良好,平均偏差＜0.036,拟合精度能够满足汽液分离设计的要求,可用于化工生产的设计、模拟与优化.     

Study of a novel halogen‐free flame retardant system through TGA and structure analysis of polymers

Butadiene‐rubber toughened styrene polymers, such as acrylonitrile‐butadiene‐styrene (ABS) copolymer and high impact polystyrene (HIPS), are noncharring polymers. They are generally blended with polycarbonate (PC) or polyphenyleneether (PPE), which are char forming polymers, to improve char forming ability for styrenic blends containing conventional phosphate flame retardants. To achieve cost effective flame retardant system, PET was selected as a potential char‐source for ABS blends through the thermogravimetric analysis (TGA) and chemical structure analysis of various polymers. PET may contribute to the enhancement of flame retardancy of ABS/PET blends, especially in the presence of small amounts of phenol novolac (PN). The effective flame retardancy of this system is believed to be accomplished through the enhancement of interchain reactions by PN. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Laboratory testing of dispersant effectiveness at high pressures

Oil spills remain a serious environmental problem, and can have significant economic and ecological consequences. Despite the advantages, accidental deep-sea oil releases during offshore exploration or production activities are of particular concern as the potential for such incidents increases significantly as we move to deeper waters. Dispersants are important mitigation tools as they have the capability to disperse the oil into a cloud of tiny oil droplets that can be readily degraded by hydrocarbon degraders if suitable environmental conditions prevail. In the case of an offshore incident, the dispersant is injected near the point of crude oil release so that dispersion is more effective. Given that our experience with subsea dispersant use is limited, the effect of pressure on the effectiveness of the dispersant has not been established, and hence, the composition and amount of dispersant to be injected has not been optimized. For typical surface oil spills, dispersant effectiveness is experimentally measured under laboratory conditions by the US-Environmental Protection Agency (EPA) baffled flask test, which was later adapted as ASTM standard method F3251. Despite its extended use, this test cannot be used for testing dispersants at elevated pressures. In order to see whether pressure affects dispersant effectiveness, we developed a simple laboratory test protocol using a high-pressure reactor (HPR). In addition, the effectiveness of five commercially available dispersants (COREXIT™ EC9500A, COREXIT™ EC9500B and COREXIT™ EC9527A, Marichem™, and Oiler 60) applied to a dead light crude oil has been determined at various pressures for the first time, and these values have been related to the standard baffled flask test (BFT) at atmospheric pressure. It is shown that pressure increase adversely affects dispersant effectiveness; however, the effect varies from a few percent to nearly a 50% decrease for a pressure increase of 100 bar depending on the particular dispersant used.     

Fällungspolymerisation von Acrylnitril in Aliphatischen Kohlenwasserstoffen. Kinetische und mechanistische Aspekte bei Verwendung des Startersystems tert.-Butylhydroperoxid/Schwefeldioxid/Trichloressigsäure

The heterogeneous polymerization of acrylonitrile in aliphatic hydrocarbons is in its kinetic behaviour similar to the bulk polymerization. This is particularly the case at low conversions (<50%). The results obtained in single-stage continuous polymerizations with short residence times are discussed in this context. The redox initiator system employed, consisting of tert.-butylhydroperoxide, sulphur dioxide and trichloroacetic acid, leads to special characteristics in the chemical structure of the acrylonitrile polymers. Parallel with the polymerization, the redox components react with acrylonitrile to form N-tert.-butylacrylamide, which can be incorporated into the growing polymer chain. A further effect of the initiator system is that the polymers formed contain a comparatively high proportion of sulphur fixed in the polymer, mainly in form of sulphonate groups. This is due to specific initiating and terminating reactions. As a result of hydrolysis the polymers also have relatively high concentrations of carboxyl groups.     

ABS干燥器着火原因分析及采取的措施

针对丙烯腈/丁二烯/苯乙烯共聚物装置干燥系统连续4次发生着火的原因进行了详细分析。并对避免着火的措施提出了见解。即采用以喷淋塔为核心的氮气循环干燥。氮气循环干燥实施后取得了明显效果。     

On the graft polymerization of styrene and acrylonitrile onto polybutadiene in the presence of vinyl acetate. II. Properties of graft polymers

The properties of the graft polymers of styrene, acrylonitrile, and vinyl acetate onto polybutadiene rubber that were prepared for the modification of graft polymers of styrene and acrylonitrile onto polybutadiene (ABS polymers) by emulsion polymerization up to a high degree of conversion have been studied and discussed. Both the impact strength and notched impact strength of the graft polymers have been found to remarkably increase with a rising quantity of vinyl acetate, in particular, in the case of styrene substitution, whereas in the case of acrylonitrile substitution by vinyl acetate, the two characteristics become noticeably poorer. The effects of the vinyl acetate amount and the type of substituted monomers on bending strength, tensile strength, Vicat softening point, and glass transition temperature of the graft polymers are also clearly different. Furthermore, the properties of the above graft polymers blended with styrene/acrylonitrile copolymers have been studied.     

钻井液用石蜡乳油的制备及应用

针对钻井液用O/W型石蜡乳液易破乳分层、析蜡结块的乳液稳定性难题,采用复配乳化剂将液体石蜡、植物油、白油组成的油脂相在一定条件下制备成有效成分含量达100%的石蜡乳油。为进一步提高石蜡乳油的润滑性,采用捏合干燥工艺对纳米二氧化硅微球表面进行预处理,并借助二氧化硅专用分散剂和稳定剂球磨分散到乳油体系中,经稳定性研究试验发现充分悬浮分散的纳米二氧化硅微球具有良好的热稳定性和机械稳定性。石蜡乳油相比于传统石蜡乳液具有更高的存储稳定性和使用便利性,可与水任意比例混溶形成O/W型石蜡乳液。性能试验表明：1%石蜡乳油加入淡水聚磺钻井液体系,API滤失量降低33.8%,润滑系数降低率28.6%,加入5%盐水聚磺钻井液体系,API滤失量降低26.7%,润滑系数降低率23.4%,石蜡乳油与聚磺钻井液体系配伍性良好,可完全替代传统石蜡乳液。该石蜡乳油在松辽盆地北8井进行了现场入井试验,试验井段井壁稳定、钻井液润滑性能提升明显,试验效果良好。     

聚合物多元醇合成与应用

简要论述了聚合物多元醇（苯乙烯－丙烯腈共聚物接枝聚醚）的发展历史、合成反应原理,介绍了其生产工艺和应用,对基础聚醚、单体、引发剂、链转移剂、分散剂等原料的作用及其选择进行了较为详细的讨论。     

A new cationic surfactant N,N′-dimethyl-N-acryloyloxyundecyl piperazinium bromide and its pH-sensitive gels by microemulsion polymerisation

A piperazine-based cationic surfactant, N,N′-dimethyl-N-acryloyloxyundecyl piperazinium bromide (DAOUPB) was synthesised by a two-step procedure. The monomer was polymerised in two new microemulsion systems: (i) DAOUPB/water/methyl methacrylate (MMA):hydroxyethylmethacrylate (HEMA) and (ii) DAOUPB/water/acrylonitrile with ethyleneglycol dimethacrylate (EGDMA) as the crosslinking agent. Transparent solid polymeric materials were obtained by photo-initiated polymerisation of some of these microemulsion compositions. Most of the bicontinuous microemulsions investigated gelled within 10 min resulting in transparent solid polymers. The electron micrographs of the polymers obtained from microemulsion compositions containing MMA:HEMA did not show any micropores, while those obtained using acrylonitrile revealed the existence of open-cell type micropores and also of the bicontinuous nature of the system. The width of the bicontinuous structure (micropores) was about 33 nm in the dry state, with long and winding channels of random distribution. The swelling of the gels was highly sensitive to pH.