中高收缩涤纶短纤维纺丝工艺探讨

探讨了影响涤纶短纤维收缩率的工艺条件。通过对原丝线密度、纺丝速度、拉伸温度、拉伸倍率、紧张热定型及松弛热定型等工艺条件的优化和控制,采用常规聚酯切片成功开发出收缩率在20%以上的涤纶短纤维。     

涤纶短纤维高温卷曲工艺探讨

在改造后的 LHV-901设备上进行高温卷曲工艺探索试验。得出卷曲数、卷曲度受卷曲主压、背压、卷曲前丝片温度影响明显。提出卷曲前丝片温度是卷曲工艺制订的先决条件。较合适的温度为120—140℃.相应卷曲机的主压、背压可控制在0.3—0.45MPa 为宜.讨论了影响卷曲前丝片温度的因素,如紧张热定型温度和叠丝上油量.确定较合适的紧张热定型温度为180℃,叠丝前丝片温度宜控制在165℃左右,上油量控制在912—960mL/min 范围内。     

杜邦干热拉伸工艺对涤纶短纤维干热收缩率的影响

通过后加工工序的优化来降低1.33 dtex×38 mm涤纶短纤维的180℃干热收缩率。指出:合适的紧张热定型温度、冷却和松弛热定型的烘燥效果可以降低该纤维的干热收缩率。     

RDJ—746S紧张热定型上油联合机的设计与制造

<正> 我厂是一九七八年发展起来的中型合成纤维厂,具有回转充填干燥+多孔纺+LVD802年产7500t 涤纶短纤维的生产能力。由于当时的历史原因,在筹建时后处理没有紧张热定型生产工艺,因此产品只能生产一般的中长纤维。一九八六年十月,我厂为了适应市场的需要,满足棉纺高速高效生产的要求;为了适应外贸的需要,满足单唛用于出口纱改善可纺性,使单纱品质指标达到3000分的要求,厂长决定在原来 LVD802生产线上加入紧张热定型生产工艺。我们在广泛选型调研的基础上,经技术论证,决定以国产 VD—862型紧张热定型机为基础,仿国外东洋纺紧张     

天津石化公司短丝装置紧张热定型机故障分析、处理与防止

介绍了化学纤维厂短丝装置紧张热定型机在运行中出现的故障,分析了紧张热定型机轴承故障的原因并提出了相应的对策,改善了紧张热定型机的运行状况,为短丝装置的平稳运行提供了设备保障。     

聚苯硫醚纤维的制备及性能研究

对聚苯硫醚(PPS)切片进行了熔融纺丝,测定了拉伸倍率、拉伸温度、热定型温度对纤维性能的影响。结果发现,随着拉伸倍率和热定型温度的提高,纤维的断裂强度和熔点都提高,断裂伸长则下降;随着拉伸温度的提高,纤维的熔点降低,断裂强度和双折射率则先降低后升高,出现最低值。在初生纤维的冷结晶温度110℃附近进行拉伸,纤维的断裂强度最低。在310℃对PPS进行纺丝,初生纤维在90℃拉伸4.5倍后,再在180℃紧张热定型5min,获得了断裂强度为3.9 cN/dtex的PPS纤维。     

涤纶短丝紧张热定型机辊轴装配技术及维护保养

介绍了涤纶短丝紧张热定型机辊轴和轴上附件及其装配技术和方法;针对紧张热定型机前轴承内圈开裂故障原因进行了实例分析,确定了滚动轴承游隙有效值的计算方法,轴承游隙值的测定需将轴承内外圈温度差纳入测定标准中;提出了紧张热定型机传动机构的日常维护和保养措施;适当增大前轴承的轴承游隙值为0.40~0.43 mm,轴承故障率降低,确保紧张热定型机长周期、满负荷运转。     

热定型对涤纶短纤维性能的影响及工艺条件初探

从涤纶短纤维热定型过程中纤维结晶度（密度）、总取向度（双折射）、继裂强度、继裂伸长率与温度的关系以及松驰热定型中卷曲率和温度的关系出发,根据洛阳石化化纤厂涤纶短纤维的成品质量指标,提出了热定型的两个决定因素－温度和时间的控制范围,并与设计提供参数进行对比,以便在今后的生产中发现、解决问题。     

普通涤纶POY制自伸长纤维的研究(英文)

研究了以普通涤纶POY为原料制备自伸长纤维的拉伸工艺。实验表明 ,在DW平行牵伸机上一段拉伸 ,二次热处理 ,适当地控制拉伸速度、拉伸倍数、拉伸温度、热定型温度、热定型时间 ,得到的自伸长涤纶性能稳定 ,干热伸长率大于 5 .0 %。     

涤纶短纤维装置增产改造

从设备与工艺两方面讨论了涤纶短纤维装置的增产改造。将喷丝孔排列从原3 600孔改为4 000孔,4个角和4个端点喷丝孔排列的倾角比3 600孔加大。选择侧吹风速度3.0~3.4 m/s,风温23℃,提高一道拉伸倍数,降低二道拉伸倍数,紧张热定型温度提高5-10℃,松弛热定型温度提高10℃,并优化了其他工艺条件,实现单线增产10％,产品质量提高。     

基于热源塔的热泵系统构建与试验

为解决水冷冷水机组冬季闲置和空气源热泵冬季制热存在的结霜问题,构建了一种基于热源塔的热泵系统。详细分析了热源塔热泵系统的构成和工作过程,依据所建立的热源塔热泵试验装置进行了不同热源塔溶液进出口温差的制热试验。结果表明:热泵制热量和COP都随着热源塔溶液进出口温差的增大而减小,而压缩机的耗功变化较小,空气与蒸发温度间的温差随之增大而增加;当环境温度为-1.2℃,热源塔溶液进出口温差从1.5℃增大到3℃时,热泵制热COP由3.02降为2.72,空气与蒸发温度的温差由7.64℃增大至11.96℃。整个实验过程中系统运行稳定可靠,避免了空气源热泵的结霜问题,表明热源塔热泵是一种非常具有前景的冷热源方案。     

Shrinkage behavior after the heat setting of biaxially stretched poly(ethylene 2,6‐naphthalate) films and bottles

Amorphous preforms of poly(ethylene 2,6‐naphthalate) (PEN) were biaxially drawn into bottles up to the desired volume under industrial conditions. These bottles were used to characterize the shrinkage behavior of the drawn bottles with or without heat treatment and to study structural variations during heat setting. During drawing, a rigid phase structure was induced, and the amount of the induced rigid phase structure was linearly related to the square root of the extra first strain invariant under equilibrium conditions. During the production of these bottles, this equilibrium was not attained because of high stretching conditions and rapid cooling after stretching. The structure after orientation contained a rigid amorphous phase and an oriented amorphous phase. The shrinkage behavior was a function of the temperature and time of heat setting. Long heat‐setting times, around 30 min, were used to characterize the possible structural variations of the oriented PEN after heat setting at equilibrium. Under the equilibrium conditions of heat setting, the start temperature of the shrinkage was directly related to the heat‐setting temperature and moved from 60°C without heat treatment up to a temperature of 255°C by a heat‐setting temperature of 255°C; this contrasted with poly(ethylene terephthalate) (PET), for which the start temperature of shrinkage was always around 80°C. For heat‐setting temperatures higher than 220°C, the structural variations changed rapidly as a function of the heat‐setting time, and the corresponding shrinkage of the heat‐set samples sank below 1% in a timescale of 30–60 s for a film thickness of 500 μm. The heat treatment of the oriented films taken out of the bottle walls with fixed ends stabilized the induced structures, and the shrinkage of these heat‐set films was zero for temperatures up to the heat‐setting temperature, between 220 and 265°C, if the heat‐setting time was sufficient. According to the results obtained, a heat‐setting time of 30 s, for a film thickness of 500 μm, was sufficient at a heat‐setting temperature of 255°C to stabilize the produced biaxially oriented PEN bottles and to take them out the mold without further shrinkage. During the drawing of PEN, two different types of rigid amorphous phases seemed to be induced, one with a mean shrinkage temperature of 151°C and another rigid amorphous phase, more temperature‐stable than the first one, that shrank in the temperature range of 200–310°C. During heat setting at high temperatures, a continuous transformation of the less stable phase into the very stable phase took place. The heat‐set method after blow molding is industrially possible with PEN, without the complicated process of subsequent cooling before the molds are opened, in contrast to PET. This constitutes a big advantage for the blow molding of PEN bottles and the production of oriented PEN films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1462–1473, 2003     

316不锈钢连铸工艺参数对结晶器内坯壳厚度影响模拟

为研究连铸过程中拉速及过热度对凝固传热的影响,采用商业有限元软件ANSYS,对316不锈钢板坯厚度生长情况进行了模拟. 采用2-D模型,分别计算了拉速为0.4, 0.5, 0.6 m/min及过热度为30, 40, 50℃时坯壳出口温度、坯壳厚度及表面温度的变化,探讨了坯壳生长及厚度变化规律. 结果表明,拉速从0.4~0.6 m/min变化,坯壳出口温度升高83℃、坯壳的出口厚度平均减薄3.2 mm、表面温度随拉速提高而升高;过热度从30~50℃变化,坯壳出口温度升高20℃、表面温度平均升高20℃、坯壳的出口厚度平均减薄1.35 mm.     

热定型张力对PAN原丝结构与性能的影响

研究了热定型过程中的张力对PAN原丝结构与性能的影响。结果表明：热定型张力对PAN原丝的物理性能影响很大;随着热定型张力减小,PAN原丝的抗拉伸强度和初始模量随之减小,而断裂后伸长率逐渐增大;沸水收缩率和取向度也随着定型松弛幅度的增加而降低。     

Effect of heat treatment on nylon-6 tire cords

The behavior of nylon-6 tire cords at elevated temperature has been evaluated. The heat treatment of cords at 200°C for 16 h was found to reduce their tensile properties considerably. This has been attributed to the decrease in average molecular weight and change in molecular weight distribution as ascertained by fractionation studies. Heat setting of cords in the temperature range of 180–210°C without any applied tension showed some decrease in tensile properties. This has been ascribed to the higher degree of shrinkage of the cords and hence increased chain folding in the molecular structure. However, irrespective of time and temperature of heat treatment, shrinkage was reduced with increasing tension on the cord. Effect of heat setting on density and crystallinity was also evaluated.     

细小槽道换热器内相变微胶囊悬浮液对流传热DPM模拟

基于离散相模型,采用颗粒比热容随温度变化分段函数描述颗粒的相变过程,模拟了相变微胶囊悬浮液在细小槽道换热器内的对流传热特性,考察了不同入口流量时换热器进出口压差及温差的变化规律,并与纯水进行比较,分析了换热器内部及加热面温度分布,研究了换热器典型通道修正的局部努赛尔数Nux*沿流动方向的变化规律. 结果表明,相变微胶囊悬浮液在换热器内的压损随流量变化规律与纯水一致,较纯水有所增大;引入相变微胶囊颗粒减缓了加热面和流体温度升高的速率,使换热器出口及加热面的温度比纯水低;受进出口位置影响,换热器内温度呈现中间通道低、向两侧逐渐升高的分布规律. 不同通道的Nux*沿流动方向的变化规律存在一定差异,部分通道内相变材料完全融化,而部分通道内相变材料尚未完全融化就流出换热器. 需改进换热器进出口位置或对换热器内部结构进行优化设计以获得较好的流量分配特性,从而改善换热效果.     

12D/05F黑色锦纶6 FDY纺丝技术研究

通过多组实验,生产中选择纺丝温度250~262℃,侧吹风温度19℃,风速0.35m/s,冷却高度700mm,含油1.0%,纺丝张力控制在5~6cN范围,牵伸比1.350,热定型温度170℃,绕丝工序环境温度19℃~20℃,湿度60%~65%,卷绕速度4500m/min,能够连续稳定生产出品质优良的产品。     

换热器壳程进出口折流区传热温差损失分析

对管壳式换热器壳程进出口折流区的传热温差作了分析,以换热器热流体与冷流体的出口温度比例α表征换热器的换热深度,探讨了换热器换热深度与长径比的关系。采用流路分析方法,对换热器壳程折流区域的传热性能进行了数学分析,并与纯逆流情况作了对比。结果表明:换热器折流区域的传热温差较逆流区域传热温差的偏离量会随α的改变而产生变化,为避免偏移量过大应控制折流区域面积占总传热面积的比例。α1时,为使传热温差偏移小于5%应使折流区域面积占总传热面积的比例小于0.6/R1 a,c。揭示了现有换热器结构大型化之后难以实现α1的原因,并给出一种可以改进传统大型管壳式换热器长径比锐减、换热深度受限的有效结构——壳程多通道结构。     

保温对地热单井换热性能的影响分析

建立了单井地热传热数学模型,模拟了单井地热流动换热过程,比较分析了不同保温材料及保温深度对采出水温度和取热功率的影响。结果表明：保温材料热导率和保温深度对系统取热功率有很大影响。当保温材料热导率为0.03 W/( m·K)和0.5 W/( m·K)时,平均取热功率分别 为732.08 kW和640.98 kW;采用热导率为0.03 W/( m·K)的保温材料,保温深度1000 m时流体进出口温差为10.33 K,保温深度为2000 m时流体进出口温差为15.98 K,保温深度为3000 m 时流体进出口温差为17.93 K。实际工程中,可以采用各种材料组合安装的形式对采出井进行保温,保温重点为井深较小处,这样既能保证采出水温,又能节约成本。     

铜材退火罐热量回收利用装置传热分析

对某厂铜件退火罐,利用风冷夹套回收其余热用于木材干燥。采用ANSYS 14．0软件模拟了风冷夹套中的流场、温度场和压力场,并根据工程实际对进气口数量进行了优化。结果表明,进气口数量的改变不仅改变了流动阻力而且影响传热效果。当进气口数量为7时,退火罐出气口空气温度适宜用于干燥木材并且取热效果良好。