Use Bags
Bill,
It is generally accepted that wet/damp products and pneumatic transfer systems are a no-no, and, after building several reactor loading systems, I would suggest that you adhere to that rule.
There are also other problems with pneumatically conveying the products (apart from the fact that the wet ones won't reach the top!) and they are dust and cleaning.
Dust - this will be a major headache as, if dense phase is used, there will be a considerable rush of compressed air escaping at the end of the batch - because the blowtank will act as an air reservoir. If lean phase is used there will be a lot of airborne dust to deal with. This will entail installing a dust handling/extraction system on the top of the reactor and the dust collected will be a nuisance because it won't be in the reactor!
Cleaning - in my experience most products put into reactors are a tad noxious so you will have a contaminated reactor adaptor to deal with every time you fill up.
I suggest you install a bag lift and overhead rail and fill using FIBC's with a simple local extraction system. That way you have only the displaced air to deal with.
If you need any help on the design please send me a message. ■
As An Afterthought - -
If you are certain that the products can be got out of the FIBC's and there is headroom above the reactors you could use a vacuum loading system design that I installed a few years ago in Runcorn for a chemical works.
This was a movable system (over 3 reactors in line) and used an FIBC station on the ground. Contact me for details. ■
Re: Pneumatic V's Fibc Charging Of Reactors
Dear Bill,
Your material has a low MIE (Minimum Ignition Energy) as defined by NFPA. These materials must be handled in inert atmosphere to prevent a dust explosion. Your main concern must be safety instead of feeding the reactor by gravity or by pneumatic conveying. Choice between these options will depend upon the economics. Both options will work. But you don't need a dense phase pneumatic conveying system for safety reasons. Dilute phase is acceptable if you use an inert gas for conveying.
Regards,
Amrit T. Agarwal
Solids Handling Consultant
polypcc@aol.com ■
Pneumatic v's FIBC Charging of Reactors
I have a project involving charging various 500- 2500kg Powders (MIE: 2mJ to 10mJ) into a Reactor. Pressure: 0, Temp: Ambient. Solvent in Reactor: Yes.
Powders in some cases will be wet cake but the majority will be dry.
In my company some say that Dense Phase Pneumatic/ Vacuum Units have great safety properties, transfer times etc.
Others say the FIBC direct charging into a Reactor using a special connector to join the FIBC to the Vessel is very good from a safety, ease of use and sterile approach. i.e. Just throw away the FIBC when done hence no CIP/ SIP needed unlike the pneumatic version.
I can decide whether to have the powder supplied to our facility in drums, IBC's or FIBC's. Can someone give me some solid advice on which way I should go. ■