You're able to provide 17,000 kW for free? Nice.
17000 w/hour you mean? 17000 KW/hr is a lot.
You would need several big 240v 15-20A A/C to cool all of that, its not a good idea, just push the air strait outside. I hope thats in a warehouse because that would be a lot of noise.
But pushing the air outside will let air in. Air in will carry dust. Isn't that bad? What kind of extractor would i need? What size?
A very powerful one, and i don't know exactly depend how much space you got to let the air through. And yes, there will be dust, so what

? Use compressed air from time to time and buy box fan filters on ebay or such.
Dust don't really do much unless you let it accumulate by the inch. Unless you live in a very dirty environment or next to a volcano, you should be fine. Here i just blow some air through the heat sink every few months for good measure.
Never heard of an dust explosion, if dust gets too much and doesnt get cleaned, it heaps up. That is explosive and with the miners being hot, that is the ignition source and boom it blows up. Dust is dangerous!