dust and ammoniac problem in electrical room

Hi guys,



This is not typical automation question or discussion, but I believe that it could be asked here.



For my next job I need to find some solution for main electrical room in compost production factory. Main problem is dust; it’s very small so it finds mysterious ways to get in room. Dust is very clammily and aggressive so frequency converters inside have died few times (bad luck said that need to be more expensive one ABB ACS 800 and Omron E7).

Next problem is ammoniac. Compost dust is full of it and on temperature in room it depart from dust and really smells and hurts eyes so electricians can’t work inside.



In principle, I know what I need to do. I need conditioning air to put down temperature and wetness of air. Next, I need to pump clean air inside and to pump it lower in the room and need to press out higher air because air is heavier that ammoniac.

What I want to ask you here is have someone has similar experiences? Some tips n trick are very welcome; maybe some original solutions or at least some discussion.

Best Regards

Lesa

we used a vortex type device to cool and pressurize a plc cabinet one time. Worked great.
It wouldn't do for an entire room though
See http://www.exair.com/en-US/Primary%20Navigation/Products/Vortex%20Tubes%20and%20Spot%20Cooling/Pages/Vortex%20Tubes%20and%20Spot%20Cooling%20Home.aspx
for an example
Steve.

Thank you Steve for reply
.
When you say PLC, it would be very sad day for us all if our S400 dies. Next, PC for SCADA i down there too and thay have 50m cable for mouse, keyboard and monitors.
Electical room is planed to be most clean room in factory, but...

We deal with flour dust in our plants. Like your product, it's small particles that find their way everywhere. But, fortunately, we don't have to deal with the ammoniac.

Our control rooms and MCC rooms are pressurized. If you can have a slightly positive pressure in your electrical room, it should help greatly with the issues you mention.

OZEE said:

We deal with flour dust in our plants. Like your product, it's small particles that find their way everywhere. But, fortunately, we don't have to deal with the ammoniac.

Our control rooms and MCC rooms are pressurized. If you can have a slightly positive pressure in your electrical room, it should help greatly with the issues you mention.

Click to expand...

I will double that. Will add place blower in clean outside air and install filters 99% should be fine or if you are worried 99.9 - you should not need HEPA. Put in roughing filters (that roll type filter media should be just fine and change that once a week until you get an idea of what ******t (oops forgot A M B I E N T) dust loading is. Pressurize room to just a couple inches water pressure - should nearly eliminate dust and ammonia smell. Dump the air to the inside of the rest of the building - they can use the ventilation also. If your outside air is drawn in from a shady portion you many not need to chill the air. I would recommend a room air change rate of 1 to maybe 3 per minute. Get your blower oversize and drive with VFD. If 1 or 3 air changes per minute are not enough speed up the blower IAW with its chart.

The hard part is to predict what the wind is going to do - do you have a record ie wind rose of the prevailing winds and their direction??
Not a cheap solution I admit but with a little engineering and bucks you should fix it the first time and be DONE with it. OR you can spend lots more time fooling around pleasing the beancounters and spend bunches more.
Dan Bentler

Thank you guys for reply. I like your solution.



I don't need to predict wind rose because electrical room is on the corner of the factory so I have two walls to outside of the building and can pump in on the one side and pump out on another.



“Little” problem will be budget; can I afford all that but that’s not subject.

If you don't need to cool, it doesn't take very much horsepower to pressurize a room. A 2 or 3 HP squirrelcage blower usually does just fine. You just need enough CFM... And, like Dan suggested, put a VFD on it so you can easily tweak its settings if necessary.

I used to be an industrial hygienist in industry. I was the guy they called with indoor air problems. Too many times designers forgot to allow (or could NOT) for variations in wind direction.

The other neat thing about using VFD on blower is that when someone opens a door to enter room the VFD will speed up blower to blow more air thru the open door - once it is open - you dont have to break your back overcoming high pressure differential across door.

Dan Bentler

for cooling use a heat exchanger in one side of the cabinet this way no air gets inside the box and no ammonia. so keep the cabinet airtight, explosion proof is also good. ammonia can explode easily so be carefull.
compost is as dangerous as gasoline and client should be aware of danger for explosion and fire. cooling by vortex is fine if air is clean or the cold air stays in a tube (not copper as ammonia likes it) (in bottom of cabinet for condensing water).