水力输送下改性双基推进剂药粒的快速安全烘干

Rapid and Safe Drying of Modified Double-base Propellant Pellets under Hydraulic Transportation

为了探究水力输送条件下含硝胺改性双基推进剂药粒的快速安全烘干工艺条件,对水力输送过程不同停留时间的推进剂药粒进行吸水率分布测试并开展了烘干实验,采用热分析仪、摩擦及撞击感度仪、扫描电镜分别测试分析了推进剂药粒在水力输送前后的热分解特性、感度特性和微观形貌。结果表明,在2min的水力输送停留时间下,推进剂药粒基本达到饱和吸水量(约10%),随着停留时间(2、5、10min)的延长,水力输送下推进剂药粒的吸水量略有增加,但整体变化不大,均在10%~11%之间;水力输送前推进剂药粒在不同温度下(80、110、140℃)的恒温热重曲线表明,推进剂药粒适合的烘干温度为80℃;对比水力输送后推进剂药粒在80℃下的水浴烘干和鼓风烘干过程,鼓风烘干过程中推进剂湿药粒和热风存在更大的热交换,可以在更短的时间(23min)内达到烘干状态,避免推进剂药粒需要干燥而长期暴露于高温条件;水力输送前后推进剂药粒的感度和微观结构均无明显变化;表明水力输送条件下含硝胺改性双基推进剂药粒的饱和吸湿量约10%,采用鼓风对流传热方式,在80℃条件下可实现推进剂药粒的快速安全烘干。

In order to explore the rapid and safe drying process conditions of modified double-base propellant pellets containing ammonium nitrate under the hydraulic transportation,the water absorption distribution of propellant pellets with different residence times in the process of hydraulic conveying was carried out and their drying experiments were investigated.The thermal analyzer,friction and impact sensitivity meter,and scanning electron microscopy were employed to test and analyze the pyrolysis characteristics,sensitivity feature and microstructure of propellant pellets before and after hydraulic delivery.The results show that the propellant pellets basically reach the saturated water absorption(10%)with 2min hydraulic conveying residence time.With increasing the residence time(2,5,10min),the water absorption of the propellant pellets increases slightly,but the overall change is not obvious,which is in the range of 10%-11%.It is found that the suitable drying temperature of propellant pellets is 80℃according to the thermogravimetric curves of the propellant pellets at different temperatures(80,110,140℃)before hydraulic transportation.Compared with the process of water bath drying and air blast drying at 80℃after hydraulic transportation,there is a great heat exchange between wet propellant pellets and hot airblast dyring,so the wet propellant pellets could be dried in a shorter time(23min)to avoid a long-term exposure to high temperature.The sensitivity and the microstructure of the propellant pellets do not change significantly before and after the hydraulic transportation.It can be showed that the saturated moisture absorption of modified double-base propellant pellets containing ammonium nitrate is approximately 10%under hydraulic transportation,and the fast and safe drying of propellant grain can be realized at 80℃by means of air blowing and convective heat transfer.