热空气-微波耦合天然橡胶干燥机设计及其干燥动力学研究

为了解决天然橡胶加工中存在的干燥时间长、能耗高、环境污染和设备占地较大等问题,设计了一种热空气-微波耦合天然橡胶干燥机,以实现两种干燥方式优势互补,提升天然橡胶加工干燥技术水平。以胶乳级颗粒胶为研究对象,采用该设备研究了微波干燥和热空气-微波耦合干燥特性,及耦合干燥动力学。研究发现:当天然橡胶初始含水率高时,采用微波干燥容易使橡胶受热不均匀,从而发生内部局部过热,使胶粒发粘变坏,影响天然橡胶的性能;而采用热空气-微波耦合干燥,橡胶的干燥时间由单独用热空气干燥的415.8 min降至耦合干燥的107 min,且干燥过程传热比较均匀,得到的橡胶品质较好。根据天然橡胶的水分变化规律,建立了天然橡胶热空气-微波干燥动力学模型,其动力学模型为:MR=(1-a)exp(-0.0485t~(0.685))+(1-b)exp(-4.76×10~(-76)t~(35.905))。

The Design of Hot Air and Microwave Coupled Dryer for Natural Rubber and its Dynamic Model

The hot air and microwave coupled dryer for natural rubber was designed to solve the problem existed in natural rubber processing for example long drying time, high energy consumption, environmental pollution, and Larger equipment, etc. This machine can realize complementary advantages of two kinds of drying method. The latex standard China rubber(LSCR)was regarded as objection to investigate the drying characteristics of microwave and coupled drying, and coupled drying dynamic model. The results showed that the natural rubber became sticky and deteriorated, which influenced the quality of LSCR. Because water in rubber particle was over-hot and non-uniform heat transport, when the initial water content was high. However, the coupled drying was adopted to LSCR, whose drying time was reduced from 415.8 min in case of hot air drying to 107 min, and the heat transport was uniform. Thus, the quality of LSCR was good. The dynamic model of the hot air and microwave coupled drying was constructed according to moisture variation law, and the dynamic model is MR=(1-a)exp(-0.0485t0.685)+(1-b)exp(-4.76×10-76t35.905).