工艺及设备

20031230PA6生产的新成本效益Stibal W.;Chemieal Fibers International Man一MadeF iber Year Book,2001,p.sl(英)Ems xnventa一Fischer建造日产130吨尼龙6一步法聚合物生产装置和日产250吨两步法聚合物生产装置。生产工艺包括:聚合、蒸馏、进料、再聚合,蒸发、萃取和干燥。浓缩萃取水再聚合在VK管于大气压力下进行以减少环状二聚物浓度。将环状二聚物浓度降至热力学平衡水平是可能的,但温度和时间必须与其相适应。改进后的VK管可将环状二聚物浓度降至1.2%。标准VK管的环状二聚物浓度为2.2%。用再聚合原料生产的尼龙6产品质量与那…     

国内外直型 VK 管的差距

对国内外一部分尼龙6厂家使用的直型 VK 管进行了实地考察和对比,认为国产直型 VK 管处于落后状态:设备结构过于简单,生产能力小,所生产的产品质量较差。爱姆斯—伊文达公司设计的直型 VK 管比较先进,设计合理,在技术上处于领先地位。针对国产直型 VK 管存在的缺陷,建议有关研究设计院研制具有中国特色的直型 VK 管,以利于发展我国的尼龙生产。     

精馏塔的双温差控制

提起精馏塔的控制,人们就会想起提馏段和精馏段温控。简而言之,提馏段温控就是恒定塔顶回流量,通过调节再沸器的进热量来控制塔底产品的质量;精馏段温控则是恒定再沸器的进热量,通过调节塔顶回流的方法来控制塔顶产品的质量。在此基础     

侧吹风空调装置的节能措施和效果

介绍了化纤纺丝专用侧吹风空调机组的两项节能措施:采用风机变频调速器与原有风阀自控调节系统配置;夏季温控调节采用降温去湿为主,取消绝热加湿喷淋方式,达到减少二次能耗的目的,取得了显著的经济效果。     

7.63m焦炉吸气管翻板控制逻辑优化

针对网络通信故障时,7.63m焦炉控制系统逻辑存在的主要问题,采取了两种解决办法:改变焦炉集气管压力数据传输方式和增加吸气管翻板断网保位功能。通过对7.63m焦炉吸气管翻板控制逻辑优化,工业以太网络通信中断后能保证焦炉不会放散,并且吸气管翻板可以正常调节,焦炉集气管压力保持稳定状态。     

己内酰胺连续水解聚合过程数值模拟研究

基于Polymer Plus聚合模拟软件建立己内酰胺(CPL)一段式常压VK管水解聚合合成聚己内酰胺(PA 6)的聚合模型,模拟了生产PA 6的连续聚合过程,将PA 6相对分子质量(M_n)、CPL单体转化率(X_(CPL))和可萃取物含量(W_(EV))及环状二聚物(CD)含量(W_(CD))等模拟结果与文献实际数据比较,优选模型参数;考察了进料量、进料含水率、醋酸含量、单釜温度以及全釜温控对X_(CPL),M_n,W_(EV),W_(CD)等聚合物反应及聚合物质量关键指标的影响。结果表明:模拟结果与文献实际值相差不大,随着进料量的增加,PA 6的M_n,X_(CPL),W_(CD)均降低,W_(EV)增加,当进料量为2 250 kg/h,水的质量分数约2.5%时,PA 6的M_n,X_(CPL),W_(CD)均趋于恒定;随着醋酸含量的增加,M_n明显降低,X_(CPL)几乎不变,W_(CD)略微降低;对于预聚釜(CSTR1)、缩聚釜(STR2)及后聚釜(PFR),其中CSTR1温度对M_n的影响最显著,PFR温度对W_(CD)和X_(CPL)的影响最显著;VK管的温控模式采用先升温后降温(255,260,255℃),所得PA 6的质量最好。     

VK管停机清洗几种方法的比较

介绍了用三甘醇(TEG)、乙二醇(EG)和己内酰胺(CPL)、醋酸(HAc)与脱盐水作溶剂来清洗VK管的方法,并进行了比较。经实践证明:在正常短时间停机情况下,用CPL、HAc、脱盐水来清洗VK管是一种简单实用的方法。     

PA6水解聚合反应数学模型及其实验验证

建立了PA6熔体在VK管中边流动边聚合的聚合反应数学模型,采用流态显示技术和文献报道的测定数据验证了数学模型的可靠性,还研究了熔体在具有优化科挡板内部结构的VK管中流过10块交替排列的挡板过程中停留时间分布、单体的转化率、产物的聚合度的变化规律,并从聚合指标反证了挡板结构的合理性。     

解耦控制在精馏塔温度控制中的应用

本文详细介绍了解耦控制的基本知识，以及在计算机控制时如何进行程度设计，并将它应用于精馏塔温控系统中，以此来提高塔底塔顶产品质量。     

基于PID分段式温度控制系统的设计与实现

通过对PID算法及控温方式的改进,提高温控系统的控温精度,采用分段温控技术,使其具有稳定性好和超调小的特点。     

国内外尼龙6聚合管的差距

针对国内外尼龙６生产厂家所使用的聚合ＶＫ管进行了比较．与国外同行业相比，认为我国的聚合管无论从产量还是产品质量均处于技术落后状态，聚合管内部结构简单，所生产的产品质量差。德国Ｚｉｍｍｅｒ公司设计的ＶＫ管较先进，结构设计合理，当前在技术上处于领先水平。对国产ＶＫ管存在的问题提出一些看法。     

尼龙6聚合管内微分发热量与温度分布

<正>1引言 尼龙6是合成聚酚胺生产中最重要的产品之一[1]，目前工业上多数采用水解聚合。本文涸绕尼龙6聚合反应工程开发的一系列工作都是为这一技术路线国产化提供理论基础。近卫0年来，尼龙6聚合的各种主、副反应精确的动力学数据已有报道[2,3]，目前的重点已转向工业化生产反应器中各种物理过程的模拟，诸如传热、流动、混合、停留时问分布、蒸发脱水以及过程优化控制等领域。     

浅析JN60-3型焦炉热工管理

通过对焦炉热工管理工作中的煤气流量、结焦时间、标准温度、看火孔压力、烟道吸力、空气口开度、空气过剩系数、蓄热室顶部吸力、孔板直径可调节措施之间关系进行分析,找出适合JN60-3型焦炉生产实际所需要的控温方法,制定适合热工控制措施、焦炉炉温调节较为合理的方案。使全炉温度稳定且分布均匀,以达到使炭化室内煤料能均匀受热,从而生产出优质的炼焦产品并尽可能保持炉体结构的完整与严密。     

15kt/a国产锦纶6连续聚合装置切片高速纺丝工艺探讨

介绍了国产 15 kt/a聚合装置生产的 YH5 0 0 C锦纶 6有光切片在高速纺装置上的生产情况 ,调整纺丝温度 ,控制侧吹风温度 2 0℃ ,速度 0 .4～ 0 .5 m /s,RH为 65 %～ 75 % ,上油率为 0 .5 %～ 0 .8% ,调整冷却集束点位置 ,选择合理的聚氨酯摩擦盘和热箱温度 ,则可生产出质量稳定的 15 5dtex/48f锦纶有光 DTY产品。     

国产18T/d PA-6切片聚合装置介绍及改进设想

本文介绍了上海东民化纤设备厂制造的φ1400mmVK管的结构性能及工艺控制,并根据其在生产中的应用情况,提出了一些可行的改进建议。     

己内酰胺聚合管V型挡板的研制

在己内酰胺直型聚合管设计中采用了 V型挡板 ,经模拟试验和实际应用 ,效果均十分明显。采用 V型挡板改善聚己内酰胺熔体的径向混合效果 ,有效地减少己内酰胺熔体的径向温差 ,确保聚合物相对分子质量的稳定     

Polyamide-6 polymerization and its melt flow in the VK tube reactor with optimized baffle structure

The flow mechanism of Polyamide-6 (PA6) melt over conical perforated baffles in the VK tube is elucidated by computerized analysis based on a rational assumption of Stokes' flow. The governing equations for a two-dimensional flow are solved by the finite difference method to generate the stream function profile, velocity field and residence time distribution. Optimization of the geometries of the baffle structure brings about a uniform residence time distribution, so as to ensure a homogeneous extent of reaction for the final product. The complete mathematical model for PA6 polymerization while flowing through the VK tube was established according to PA6 hydrolytic polymerization kinetics. The optimized baffle structure was shown to be compatible with the desired polymerization variables.     

A literature survey and an experimental study of coal devolatilization at mild and severe conditions: influences of heating rate, temperature, and reactor type on products yield and composition

Coal devolatilization studies to maximize the yield of condensable products by operating at elevated temperatures and heating rates have been published. The objectives of this study were to investigate the influences of relatively mild operating conditions (e.g. relatively low temperature and pressure) on product quality, by comparing devolatilized products obtained at various temperatures and heating rates. Fixed bed, fluid bed, and entrained flow reactor units were used to obtain pyrolysis products. In addition, literature data on tar yields in various reactor units at a range of temperatures and residence times were surveyed and compared with experimental data. The liquids were characterized by a number of techniques, including field ionization mass spectroscopy (f.i.m.s.), sequential elution solvent chromatography (s.e.s.c.) and elemental analysis. The results demonstrate that the quality and yield of liquids obtained at a rapid heating rate are functions of peak pyrolysis temperature. It was shown that at a rapid heating rate, the yields of heavier polyfunctional groups (i.e. hydrocarbons with greater mean molecular weight) are greater than those obtained in the fixed bed slow heating rate reactor. The liquids generated at a slow heating rate are of lower molecular weight, viscosity, and sulphur content, and of higher H/C atomic ratios compared with the liquids obtained in a rapid heating rate unit. The effect of increasing the maximum pyrolysis temperature (at a constant slow heating rate) was to increase the yield of light gases (mainly H) at the expense of char hydrogen content and char reactivity. The tar yield is not markedly influenced when the peak devolatilization temperature is increased at a relatively slow heating rate. However, the quality (as defined by the H/C (atomic) ratio) of the liquids, and the reactivity (in air) of char, was reduced when the peak pyrolysis temperature was increased. At a rapid heating rate, the primary products, which have many structural characteristics of the parent coal, are devolatilized. The quality of the liquids obtained at a rapid heating rate is, therefore, determined by the devolatilized primary coal fragments evolved at the devolatilization temperature. In a slow heating rate fixed bed unit, however, the primary coal fragments undergo additional cracking reactions which involve stabilization of free radicals by donatable hydrogen. This leads to the formation of low molecular weight hydrocarbons of relatively higher quality. In-situ (both intraparticle or extraparticle) stabilization of reactive coal fragments by donatable hydrogen may lead to a significant improvement in the overall quality of the pyrolysis liquids in a fixed bed system in which time-temperature history is conducive for such reactions.