Brainstorming Options for best mode of feeding Solids into a Batch Reactor

[plantprowler]

I am brainstorming options to feed solids (approx. 500 kg) into a batch reactor (5000 L capacity). The solids are hard, crystalline, non-toxic, high-melting point, non-flammable. Granules / Prills. The solids come in bags which are weighed to deliver the right dose.

The feed also contains a organic liquid feedstock and water but in subsequent batches a part of the water of the previous batch is reused with partial recycle and the rest make-up. At the required dose the solids are completely soluble in the water quantity used for a batch.

Some options I was thinking about:

(1) Suck in with a hose / pipe & a vacuum through a top nozzle. (Reactor is already designed for full vacuum duty. But downside is that vacuum utility is not otherwise needed for reactor operations so must be specially provided. Also the vent condensor would need to be isolated so not easy.)

(2) Dump from some kind of hopper arrangement attached to one of the top nozzles. But a positive seal would be needed after batch starts.

(3) Have a feed tank where a solids + water solution is made and send that to reactor (downside is the agitator etc. duplication in feed tank)

(4) Some sort of inline mixer kind of arrangement where the solids get entrained with the water as it is being dosed into the reactor? Through some hopper sort of arrangement. Analogous to how a liquid may be injected via a dosing pump into a feed line. Does this exist?

Comments, thoughts, ideas?

 

[ashtree]

Do you pump recycle as part of the mixing process?
If you did you might be able to get enough vacuum induction to suck in the granular material but 500kgs is a fair amount when dealing with only 5000 litres.
I would be thinking along the lines of a "dump in " type system. By what you are saying i am assuming your are feeding this into a closed reactor vessel. Is that assumption correct?
Option 3 could be done pretty cheap even though it is a duplication.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[plantprowler]

Thanks @Ashtree.

Yes, there is partial pumped recycle plus makeup.

Can you elaborate more on what you mean by a "dump in" type system? Is it a hopper attached to a nozzle with something like a butterfly valve in between?

Yes, it is a closed reactor vessel mostly except for one nozzle that goes to an overhead vent condensor. The actual reaction is carried out at ambient pressure.

Yes, due to its simplicity I too am in favor of Option #3. Option #2, the hopper mounted on the reactor, is also attractive.

 

[met11]

Not sure about your plant layout, but a lock-hopper arrangement should work well. A lock hopper with butterfly valves on the top and bottom. I think that would be your cheapest option.

 

[geesamand]

If there is an agitator present, don't "dump" the solids onto the agitator components or force the agitator to start in a settled bed of the solids. Most agitators are designed to run in mixture of solids+liquids and not drive through solids alone. Agitators can be made that sturdy if need be, but it makes for a very expensive agitator that costs more than a controlled feed-in method.

 

[koshyeng]

I will go with option 3 too.

Based on the solubility of the solids in water, you can make a thicker solution in a smaller vessel and pressure transfer to the reactor. Assuming you can have the mixing vessel above the reactor floor.