Material needs to be added during the reaction process, but what if air gets mixed in?
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In fine chemical manufacturing, during batch reactions, solid materials must be added multiple times. There is a slight negative pressure inside the reaction vessel, and the manual lid has to be opened in order to add these materials; however, air can enter as well. Since the vessel contains flammable liquids of Class A, the presence of air inside could create an explosive gas environment, which is quite dangerous. Is there a good solution for this kind of operation? ? Is there a closed solid feeding method? Is a nitrogen seal preferable?
Set up the feeding bin; after purging it with nitrogen, it can be added to the feeding port.
This is a very common design: a feeding system is created, and this system is sealed using nitrogen; there are two layers of feeding tanks, and by stacking one on top of the other, airtight sealing is achieved
1. Following the principle of the glove box’s feeding chamber, the material enters a sealed transition chamber; the air inside this chamber is removed by evacuation before the door on the other side is opened to allow feeding. 2. The feeding chamber can be isolated from the reactor using valves; after the air in the feeding chamber is removed, the valves can be opened to feed the material, either by melting the material and letting it flow through the valves or by using a feeder
A spiral feeding system can be designed, with nitrogen sealing for the system.
The silo is equipped with a nitrogen seal, and an air shut-off device is installed on the pipeline leading to the tank at the lower part
If it’s nitrogen-sealed, how is feeding carried out? When the door of the storage container is opened to add material, doesn’t the nitrogen escape?
Dual-sealed chamber: valves are opened sequentially via automatic control for nitrogen purging as a protective measure; if possible, an oxygen analyzer should be added for interlock control.
The nitrogen is located at the bottom of the silo and is used for purging before feeding material into the silo. It’s safe if the nitrogen escapes; it doesn’t pose a threat to people (nitrogen is extremely dangerous in confined spaces, but it isn’t a hazard once it escapes from such spaces). The flow rate of nitrogen can be increased.
A feeding tank can be added to the equipment; it is connected to the equipment via a large-diameter ball valve. The size of the feeding tank is determined based on the amount of material to be fed. A feeding funnel is placed above the feeding tank, and this funnel is also connected to the feeding tank using a large-diameter ball valve. Nitrogen sealing or a slight positive pressure can be used to prevent air from entering. After feeding is complete, the entire system is purged.