液体聚丁二烯橡胶的脱挥工艺

将质量分数为10.00%的聚丁二烯橡胶溶液水洗至中性后加热,加热后的胶液经预热器、浓缩器顶部分配盘分配后进入落条式脱挥器的列管中,聚丁二烯橡胶溶液在下落过程中经落条式脱挥器进一步浓缩至质量分数大于25.00%。研究了胶液浓度、进料速度、预热温度、落条式脱挥器的温度及压力等工艺条件,结果表明,落条式脱挥器脱挥工艺适用于液体聚丁二烯橡胶溶液的脱除溶剂,所得产品的微观结构含量与国外同类产品基本相当。     

影响高橡胶接枝粉白度的因素和解决方法

本文在采用乳液接枝聚合方法生产ABS树脂的过程中,通过探究HRG高橡胶接枝粉白度的影响因素,提出了减少HRG聚合釜胶乳储存时长、在中间胶乳储罐加入灭菌剂、提高清理HRG高橡胶接枝聚合釜和中间胶乳储罐的频次、降低高橡胶接枝胶乳出料温度、控制絮凝干燥工序残酸等方法,可有效提高HRG高橡胶接枝粉的白度,降低ABS树脂的色差。     

薄膜蒸发器内流体流动特性的数值模拟

建立了薄膜蒸发器的计算模型,采用大型计算流体力学(CFD)分析软件CFX4.4模拟了薄膜蒸发器内水及粘性料液的流动过程,得到了各种速度分布. 结果表明,刮板转速、进料量对流体流动状态影响显著. 提高刮板转速,可明显促进液膜和圈形波内流体的物质交换. 在任一转速下,各料液均存在同一最佳进料量,此时其圈形波截面内平均速度达到最大值. 对纯物质水,最佳进料量对应的流动边界层厚度与膜厚之比最小. 粘性料液和水的轴向速度分布存在差异,且在液膜厚度内未形成明显的流动边界层.     

橡胶黏合剂RA65的制备装置

<正>本实用新型涉及一种化工设备,具体为橡胶黏合剂RA65的制备装置,包括圆柱形的釜体,釜体顶部有盖子,盖子下表面通过弹簧安装有分料筛网,分料筛网顶部有进料软管;釜体侧壁有多个液体进料喷口,液体进料喷口位于分料筛网下方;液体进料喷口下方有搅拌器;搅拌器的驱动装置安装在釜体底部,釜体底部有环形出料口,环形出料口下方连接有缓冲出料口。     

日本窒素公司高温进料工艺的技术要点分析

目前,根据进料脱盐水的温度区分,悬浮法PVC生产主要有4种进料方式：①冷进料,脱盐水的进料温度一般为环境温度;②中温进料,脱盐水经过加热,温度大大高于环境温度,聚合釜全部进料结束后接近（但仍达不到）聚合温度;③美国诺誉公司高温进料,脱盐水经过加热,     

薄膜蒸发器在生产中遇到的问题及改进措施

主要介绍了固定刮板式薄膜蒸发器的构造及原理,在回收苯乙烯过程中遇到的问题,包括刮板破损、筒壁损坏、管线堵塞等问题,分析了加热介质、刮板材质、筒壁磨损等问题对薄膜蒸发器平稳运行的影响,并针对出现的问题提出了改造措施。通过对支撑板、加热蒸汽以及焦油冲洗管线的改造,取得了良好的效果,使薄膜蒸发器平稳运行周期延长,每年可为公司增加经济效益124.32万元。     

橡胶干燥过程的动态模拟

橡胶的干燥特性是干燥设备设计的关键.本文结合实际的干燥系统,建立了橡胶干燥的数学模型,编制了橡胶干燥过程的动态模拟程序,对干燥过程进行了动态模拟,并分析了影响橡胶干燥的主要参数.模拟结果表明:新风流量与循环风流量越大、干燥温度越高,则干燥效果越好,但随着新风流量与循环风流量以及干燥温度的提高,其干燥速度的变化幅度越小.     

回转式薄膜蒸发器在制药工业中的应用

<正> 薄膜蒸发器是一种多用设备,用以强制产生液体薄膜,从而强化传热和传质过程。薄膜蒸发器首先被应用于食品工业,如乳制品的干燥;现在制药工业也广泛应用。我厂阿斯匹林母液回收和双乙烯酮的蒸馏都用到薄膜蒸发器。但我们所用的薄膜蒸发器结构比较简单,为立式园筒形,上部进料,料液经上部回转的园盘,甩到壁上进行传热,甩盘和园筒壁的间隙很小,所以液膜很薄,总传热系数很高。加热方式是用蒸汽夹套。     

反应精馏合成草酸二乙酯的工艺研究

研究了反应精馏合成草酸二乙酯的工艺条件,在自行设计的反应精馏塔内考察了挟带剂种类及用量、塔釜温度、进料速度、回流进料比对酯化反应的影响。环己烷为较适宜的挟带剂,确定了最佳工艺条件：塔釜温度为110℃,进料速度0.8 mL/min,回流比3。在最佳工艺条件下草酯二乙酯的酯化率达到92.16%。     

橡胶对抗冲击聚苯乙烯产品质量的影响

为提升抗冲击聚苯乙烯产品质量,试用了几种国产橡胶。研究了橡胶品种、用量以及橡胶粒径对抗冲击聚苯乙烯产品质量的影响,结果表明使用低顺式聚丁二烯橡胶A生产的抗冲击聚苯乙烯产品综合性能最好,主要质量指标及其稳定性更为出色,橡胶用量在8%时产品综合质量最佳,橡胶粒径通过调整预聚釜搅拌器转速来实现,预聚釜搅拌速度控制在43～53 rpm可获得理想的产品综合质量。     

Agitated thin-film drying of foods

Agitated thin-film drying (ATFD) has been proposed for efficient and mild drying of viscous liquid foods, pastes or pureed foods. We report a study on the influence of product and process parameters on ATFD. During ATFD of spinach leaf slurries, the wall temperature mainly affected the specific evaporation rate, while the absolute evaporation rate was proportional to the feed rate. The fact that blade rotation speed had limited effect on the drying rate suggested that the process is limited by heat transfer through the wall. ATFD is especially suited for slurries that show relatively limited sticky behavior during drying and liquid–solid phase transition with corresponding brittle viscoelastic behavior. This was demonstrated by drying juices from tomato and bell pepper, giving poor results, and by drying solutions from whey protein isolate (WPI) and sucrose, which could be successfully dried.     

乙丙橡胶湿法脱挥工艺研究

采用乙丙橡胶(J-2070)胶液进行了凝聚、挤出脱挥的实验研究。采用改造后的喷嘴结构及合理的加料方式,有效地提高了胶液凝聚过程中的脱挥效率。采用改造后的Ⅱ型模头,进行乙丙橡胶水凝聚样品的挤出脱挥实验,实验结果表明:在挤出机模头压力3.6 MPa机头温度为154℃时,挤出样品的w(总挥发分)0.5%;在挤出机转速为50~120 r/min的范围内,挤出样品不发生降解,说明该脱挥工艺可行,满足乙丙橡胶脱挥的要求。     

Controllability and energy efficiency of a high-purity divided wall column

The divided wall column system is a promising energy-saving alternative for separating multi-component mixtures. However, high energy efficiency and stable operations can only be achieved with careful design of steady state operation and control scheme. In this study, the effects of liquid split and vapor split ratios on the energy efficiency and controllability of a divided wall column system for separating ethanol, n-propanol, and n-butanol were investigated. A region with high energy efficiency was identified. However, relative gain analysis found that the performance of multi-loops composition control would be very poor. Dynamic tests showed that multi-loop temperature control cannot return the product compositions to the desired values in case of feed composition disturbances. Outside this region, composition control can compensate for external disturbances such as feed flow rate and feed composition changes but not changes in operating region caused by internal variations such as liquid and vapor splits. Offsets in the product purities were found if temperature controls were used and there are disturbances in feed composition or changes in operating region caused by upsets in liquid and vapor splits. There is a trade-off between energy efficiency and controllability. A composition + temperature cascade scheme was proposed to stabilize the operation with high energy efficiency. The proposed scheme was able to maintain high product purity and reject external disturbances in feed flow and composition changes as well as internal disturbances such as changes in liquid and vapor splits.     

Study of Phenol Removal from Aqueous Solutions by a Double Emulsion (W/O/W) System Stabilized with Polymer

Polybutadiene rubber was used for stabilization of the emulsion for removal of phenol from aqueous solution via emulsion liquid membrane technique. The results showed that the addition of the polymer increased the stability of the emulsion, considerably. The effect of various parameters such as polymer concentration, temperature, mixing intensity, internal phase concentration, phases ratio, and pH of feed phase was studied. It was found that by increasing the volume ratio of emulsion to feed, internal phase concentration, and decreasing pH, the extraction efficiency was increased. Under optimum conditions, an extraction efficiency of 92% was obtained within only 35 minutes.     

内冷式刮膜薄膜蒸发器的传热性能研究

在内冷式刮膜薄膜蒸发器中试装置上以粘性流体甘油为物料进行传热性能研究 ,发现刮膜薄膜蒸发时夹套导热油侧传热系数为液膜侧传热系数的 1.5～ 2 .0倍 ,传热热阻主要在液膜侧。实验还发现 ,随进料流量增大 ,进料温度升高 ,刮板转速增大 ,蒸发温度降低 ,操作压力降低 ,液膜侧传热系数会增大。结合因次分析和实验数据 ,关联物料物性、操作条件及设备尺寸等因素得到液膜侧传热系数的准数关联式。     

氧化降解天然胶乳制备液体天然橡胶的研究

使用正交试验和单因素试验研究了氧化降解法制备液体天然橡胶时的工艺条件。结果表明,影响降解胶乳相对分子质量的因子主次顺序为反应时间、温度、丙醛用量和引发剂用量。最佳降解条件为引发剂,2份;丙醛,30份;反应条件80℃×24h,得到Mn为1.2×104。随引发剂用量的增加,降解胶乳相对分子质量先下降后上升;随丙醛用量的增加或温度的升高或反应时间的延长,降解胶乳相对分子质量都下降。     

Spray Drying of Mannitol as a Drug Carrier—The Impact of Process Parameters on Product Properties

Powders intended for the use in dry powder inhalers have to fulfill specific product properties, which must be closely controlled in order to ensure reproducible and efficient dosing. Spray drying is an ideal technique for the preparation of such powders for several reasons. The aim of this work was to investigate the influence of spray-drying process parameters on relevant product properties, namely, surface topography, size, breaking strength, and polymorphism of mannitol carrier particles intended for the use in dry powder inhalers. In order to address this question, a full-factorial design with four factors at two levels was used. The four factors were feed concentration (10 and 20% [w/w]), gas heater temperature (170 and 190°C), feed rate (10 and 20 L/h), and atomizer rotation speed (6,300 and 8,100 rpm). The liquid spray was carefully analyzed to better understand the dependence of the particle size of the final product on the former droplet size. High gas heater temperatures and low feed rates, corresponding to high outlet temperatures of the dryer (96–98°C), led to smoother particles with surfaces consisting of smaller crystals compared to those achieved at low outlet temperatures (74–75°C), due to lower gas heater temperatures and higher feed rates. A high solution concentration of the feed also resulted in the formation of comparably rougher surfaces than a low feed concentration. Spray-dried particles showed a volume-weighted mean particle size of 71.4–90.0 µm and narrow particle size distributions. The mean particle size was influenced by the atomizer rotation speed and feed concentration. Higher rotation speeds and lower feed concentrations resulted in smaller particles. Breaking strength of the dried particles was significantly influenced by gas heater temperature and feed rate. High gas heater temperatures increased the breaking strength, whereas high feed rates decreased it. No influence of the process parameters on the polymorphism was observed. All products were crystalline, consisting of at least 96.9% of mannitol crystal modification I.     

顺丁橡胶聚合过程控制

丁二烯溶液聚合过程是将溶剂中的丁二烯在催化剂作用下引发聚合得到顺式1,4-含量在96%－98%的聚丁二烯胶液的工艺过程。聚合过程是整个橡胶生产中最关键的步骤,聚合反应的好坏直接影响到成品质量,通过对聚合进料量、单体浓度、反应温度、催化剂用量及配比、转化率、聚合物门尼粘度等项目的控制达到稳定聚合反应,优化产品质量的目的。     

橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺的团粒法造粒技术

采用团粒(聚)法制备了橡胶硫化促进剂N-环己基-2-苯并噻唑次磺酰胺(CBS)粒状产品,确定了团粒造粒工艺的最佳条件,并在此条件下进行了稳定运行实验.结果表明,用脱水后含水率为20%的CBS湿粉料为造粒原料,采用团粒法制备CBS粒状成品的最佳工艺条件:黏结剂乙烯-乙酸乙烯酯共聚物质量分数为CBS干基料的8%、湿粒含水率为34.77%,造粒盘倾角为35～45°、造粒盘转速为65 r/min,黏结剂乳液喷加时间约为10 min,造粒周期为50～60 min,烘箱干燥温度为(55±2) ℃,烘干时间为210 min;在最佳工艺条件下制得的粒状CBS性能均达到指标要求:初熔点不小于96.0 ℃,粒径为2.0～4.5 mm,粒子的平均强度在2.0～8.0 N,加热减量不大于1.00%,灰分不大于0.40%,成粒率超过60%.该粒状CBS能完全取代粉状产品,对橡胶的硫化性能无不良影响.     

端羟基聚丁二烯液体橡胶的环氧化研究

采用过氧甲酸原地法对端羟基聚丁二烯液体橡胶(HTPB)进行环氧化,通过过氧化氢消耗率、环氧值及开环几率详细讨论了反应温度、反应时间、原料配比等因素对环氧化反应影响的规律。并对环氧化产物(E HTPB)的固化性能进行了研究,实验表明EHTPB用于环氧树脂改性时有较好的共混相容性,能显著提高环氧树脂固化物的柔韧性和耐热性。