Abstract

A Study of the process followed by an Emulsion Polyvinyl Chloride droplet in a spray dryer is necessary to understand the morphology of produced dry powder. For the Production of E-PVC, vinyl chloride monomer turns into liquid under pressure and high temperature. This liquid is extracted into the water in the form of emulsion with the help of an emulsifier, and polymerization is performed using water-soluble catalysts. Investigating the operational parameters of the latex drying process can provide helpful information for the design process. In the present study, a pilot plant of Arvand petrochemical spray dryer with a scale of 1:10 is constructed and studied. The purpose of this study is to experimentally analyze the drying of E-PVC in a pilot-scale spray dryer with a particular focus on determining the effects of drying conditions on the powder properties including morphology. For this purpose, the pilot-scale dryer is constructed, and the impact of various parameters such as inlet air temperature, atomization ratio, and latex concentration on outlet temperature and powder moisture content are investigated. A scanning electron microscope is employed to observe the particle morphology parameters mentioned above. The results showed that the outlet temperature decreased dramatically by increasing the atomization ratio and latex concentration. The results showed that more than 90% of the E-PVC particles are solid spheres. About 6% of donut-like particles, about 3% of particles with pore, less than 1% of broken hollow particles. The SEM image of latex used in experiments with a concentration of 40% and a Class D was taken to determine the shape of the latex particles. The picture showed that the particles were spherical before the drying, so the particles' final deformation is due to spray parameters changes during the drying process. From the morphological viewpoint, the number of agglomerates increased at higher inlet temperatures. More than 84% of particles maintained their spherical shape and have a diameter of 15-20 microns.

摘要

有必要研究喷雾干燥器中乳液聚氯乙烯液滴的过程，以了解所产生的干粉的形态。对于生产E-PVC，氯乙烯单体在压力和高温下变成液体。在乳化剂的帮助下，这种液体以乳液的形式被提取到水中，并使用水溶性催化剂进行聚合。研究乳胶干燥过程的操作参数可以为设计过程提供有用的信息。在目前的研究中，Arvand 石化喷雾干燥器的中试装置的规模为 1:10 的建设和研究。本研究的目的是通过实验分析 E-PVC 在中试规模喷雾干燥器中的干燥，特别侧重于确定干燥条件对粉末特性（包括形态）的影响。为此，构建了中试干燥机，考察了进风温度、雾化比、乳胶浓度等各种参数对出风温度和粉体含水率的影响。采用扫描电子显微镜观察上述颗粒形貌参数。结果表明，随着雾化比和乳胶浓度的增加，出口温度急剧下降。结果表明，90%以上的E-PVC颗粒为实心球体。约6%的甜甜圈状颗粒，约3%的带孔颗粒，小于 1% 的破碎空心颗粒。拍摄实验中使用的浓度为 40% 和 D 级乳胶的 SEM 图像以确定乳胶颗粒的形状。图片显示颗粒在干燥前呈球形，因此颗粒最终变形是由于干燥过程中喷雾参数的变化。从形态学的角度来看，附聚物的数量在较高的入口温度下增加。超过 84% 的颗粒保持球形，直径为 15-20 微米。最终变形是由于干燥过程中喷涂参数的变化。从形态学的角度来看，附聚物的数量在较高的入口温度下增加。超过 84% 的颗粒保持球形，直径为 15-20 微米。最终变形是由于干燥过程中喷涂参数的变化。从形态学的角度来看，附聚物的数量在较高的入口温度下增加。超过 84% 的颗粒保持球形，直径为 15-20 微米。