■ 概述 Descriptions
◎ 闭式循环喷雾干燥系统是在密闭的环境下工作，干燥介质为惰性 气体，一般为N 2，适用于有机溶剂的物料干燥有毒气的物料或干 燥过程中易发生氧化的物料的干燥；该系统采用惰性气体作为循环 气体，对干燥的物料具有保护作用，循环气体经历载湿、去湿的过 程，介质可重复使用；氮气经加热器加热后进入干燥塔，液体物料 经螺杆泵输送至离心喷头处，液体被高速循环的雾化器雾化成液 滴，在干燥塔内完成热质交换过程，被干燥后的粉状物料从塔底排 出，被蒸发的有机溶剂气体在风机负压的压力下，把夹在气体中的 粉尘经旋风分离器、喷淋塔除尘后饱和的有机溶剂气体经冷凝器冷 凝成液体排出冷凝器，不凝性气体介质连续加热后作为干燥载体在 系统内重新循环使用。而常规的普通的离心喷雾干燥是通过不断的 送风、排风达到排湿的目的，这也是防爆型闭式离心喷雾干燥设备 与普通离心喷雾干燥设备的一个明显区别；干燥系统内干燥介质为 N 2，内部为正压操作，保持一定的正压值，如果内部压力下降，由 压力变送器来自动控制N 2进量，保证系统压力平衡。 ◎ Seal circulation spray drying system works in a seal circumstance. the drying gas is usually inert gas, such N 2. It’s applicable for drying material with organic solvent, toxic gas and the material easy to be oxidized. adopt inert gas as circulation gas, so to protect the material to be dried. The inert gas circulates after dehumidification process. N 2 is heated and then enters into drying tower. liquid material is conveyed to centrifugal nozzle by screw pump, and then it’s atomized into the liquid mist by the atomizer, the heat transferring process is finished in the drying tower. The dry product is discharged at the bottom of tower, the evaporated organic solvent is sucked by the vacuum generated by the fan. Power or solid material will be separated in the cyclone and sprinkling tower. the saturated organic gas is drained out after it’s condensed in the condenser. the gas not condensed recycles in the system after it’s heated continuously. Ordinary normal centrifugal spray drying process is realized by air conveying and exhausting process. this is the obvious difference between explosion proof type sealed circulation centrifugal spray dryer and ordinary centrifugal spray dryer. the drying media in drying system is N 2, the interior is under positive pressure. to keep positive pressure stable, the pressure transmitter controls the inlet amount of N 2 automatically.