High temperature particulate cooling

[Reeferjon]

Here's an interesting one.
Talking to a gent the other day he asked of the feasability of cooling treated particulate waste (sandy and grit to you and me) RAPIDLY from 700C down to 500C, now rapid means rapid.
The process needs to cope with 10 tons of spoil and hour.

Any ideas.
1. How to convey the stuff ensuring agitation and even cooling.
2. How to actualy remove the heat from the spoil.
3. What type of cooling medium/s would be usable.


Oh yeh, cost is not an object!

John.

[frank]

Here's an interesting one.
Talking to a gent the other day he asked of the feasability of cooling treated particulate waste (sandy and grit to you and me) RAPIDLY from 700C down to 500C, now rapid means rapid.
The process needs to cope with 10 tons of spoil and hour.

Any ideas.
1. How to convey the stuff ensuring agitation and even cooling.
2. How to actualy remove the heat from the spoil.
3. What type of cooling medium/s would be usable.


Oh yeh, cost is not an object!

John.

Hi Reefer

At those temps refrigeration is not really a consideration. The additional delta t created from ambient to, say -18c would have negligable effect on the product. Free cooling comes to mind.

What you should consider is the SHC of the medium to be used. Water has a greater SHC over air but will evaporate at a very high rate in contact with the product at 700C

The only reasonable medium really is air. To do any calculations we would need the SHC of the product and a time scale.

[Brian_UK]

I assume that the product has been treated and probably dried during the process so we do NOT want a direct water based cooling method.

I would go with Frank and suggest some form of blast air tunnel.

Interesting project...

[botrous]

Is the product to be cooled sensible to moisture ? If not , why not
combine air and water (air can be passed threw a water fountain or the water can be sprayed under pressure to the air entering to cool the product ) to get more efficient cooling , if the plant that gonna treat the product has access to an open water source like a lake or a river that would be great.

Reeferjon please send us the product specification (thermal and physical state ) so i can exercise my mind with some gymnatics , it have been a long time with no new (I mean NEW) exercise .
As it seems and as Brian said , it's an interresting project

[Reeferjon]

Ok, so what data do we actualy need, begining with SHC (do you mean Super Heat Capacity).

a. Contact cooling via a medium (water) is not an option, if a contact madium is used then that would also have to be decontaminated (however this is not set in stone (see cost is no object ).


The overview of the process is this.

1. Contaminated soil is crushed, then microwaved to 700C.
2. The spoil must then be cooled from 700C to 500C to prevent reformation of products at a molecular level.
3. The spoil will be microwaved at 10 ton's per hour.
4. Spoil is then returned to its original site decontaminated.

[Brian_UK]

Just a side comment Jon, is this a new type of reefer you are developing ??

[chemi-cool]

Hi John,

How about a belt conveyor, made from material that can withstand the heat, lots (has to be checkted) of fans from above with low speed motors, will cool it on the way to what ever takes the soil back.

chemi

[Reeferjon]

Wish it was something I was developing, but its out'a my legue.
An aquitance is trying to fill in the background bits needed to understand develope a new project.

Thought about fans....low speed fine keeps the dust down BUT I suspect inadaquate cooling or even worse surface cooling that insulates the stuff at the conveyer surface.

Best thouht I had was a corkscrew conveyer system in a large diameter pipe, the pipe would be set up like a heat exchanger, that way you would have secondary cooling and keep the spoil from the cooling medium whilst the screw kept the material flowing and well mixed.

Problem is what to use as the cooling medium.

John.

[chemi-cool]

Just air will do the job fine in this high temp difference.
A corkscrew conveyor sounds fine to me,

Number of fans can be determent simply by trying/
I have seen this system of fans and conveyors at a plastic factory where they inject huge boxes.

Chemi

[botrous]

Number of fans can be determent simply by trying/

Nice one chemi , but don't you prefer some calculations ???

[botrous]

Wish it was something I was developing, but its out'a my legue.
An aquitance is trying to fill in the background bits needed to understand develope a new project.

Thought about fans....low speed fine keeps the dust down BUT I suspect inadaquate cooling or even worse surface cooling that insulates the stuff at the conveyer surface.

Best thouht I had was a corkscrew conveyer system in a large diameter pipe, the pipe would be set up like a heat exchanger, that way you would have secondary cooling and keep the spoil from the cooling medium whilst the screw kept the material flowing and well mixed.

Problem is what to use as the cooling medium.

John.

Water is out of question due to the high tempreture , as i understand the coolant will be in a heat exchanger , that means water will evaporates and put the exchanger under high pressures , thinking of oils , as i know that most of the oils will decompose if their temp passes 150 to 175 celcius.
so the coolant inside a heat exchanger seems a little bit something difficult to apply .... unless there are some chemical products that will not decompose or evaporate on such hight temps.

What i'm for is an open system , using a corkscrew conveyer system open from the up , the air blowed by the fans will have water spray in it, this way no dust will go up , just water vapor will go up , and no problem for moisture cause the water is sprayed , so it will evaporates directly when it contacts the product taking with it a sum of energy from the product , the air heating the product will do the same .... in this case high speed fans can be used . . .

Using low speed fans , will take a lot of space ...... and i don't really think it gonna be effective . . . how many fans will be used to provide the air change needed ? remember cfm is directly proportional to the rpm (CFM1/CFM2= RPM1/RPM2)

[US Iceman]

This thread has not had any new postings in several months and I was curious how this project worked out.

Reeferjon, did this project move into development?

This seems to be a very interesting application and I would like to find more information on how this was accomplished.

Thank you.

Best Regards,
US Iceman

[Reeferjon]

Well I did pass on our collective idea's but have not had any feedback from person involved in the project.......I guess they must have solved the problem, but it was interesting and it would have been good to see a working solution.

[botrous]

Yes Reefrejon , it woul;d have be nice to see what they have done . . . . anyways we had a good discussion over this subject