steam injection

[Daric]

I am thinking about heating a hot liquor tank with steam injection. I am also considering a steam fed heat exchanger or an "inline steam injector" to heat the output of my hot liquor tank in the piping. The direct steam injection is certainly the least expensive route but I've been counseled against direct steam injection because of the "micro explosions" that occur when you inject steam.

Is this a concern for any of you that use direct steam injection for a hot liquor tank and has anyone had damage to their plant due to these "micro explosions"?

[absaroka]

Never heard of "micro explosions" for steam injection. Maybe someone else can school me on that one.

We've been direct injecting steam for 4 years with zero problems.

http://www.pickheaters.com/

[Daric]

The pick heaters you link to are the "inline steam injectors" I was referring to. The design apparently eliminates the "micro explosions". The micro explosions apparently happen when you inject steam directly into the tank as opposed to a device like the pick heater.

[absaroka]

You definitely want to break those steam bubbles up as small as possible when injecting. Smaller bubbles = greater surface area = faster heat up time (think carbonation stone like breweries use for force carbonation). Steam directly in a tank without an injection tube would cause a bunch of steam/air to just rise to the surface in large bubbles with less efficiency.

[ViolentBlue]

the micro explosions you're referring to are most likely the steam bubbles rapid cooling and collapsing, which causes a popping sound. it can be violent enough to shake equipment loose or wear things out quicker.

think of the old time thump keg than moonshiners used, this operated on the same principle. if the equipment is properly designed to take this stress, then theres no real problem, but yes smaller bubbles means smaller pops, and much less stress.

[coop]

I am thinking about heating a hot liquor tank with steam injection. I am also considering a steam fed heat exchanger or an "inline steam injector" to heat the output of my hot liquor tank in the piping. The direct steam injection is certainly the least expensive route but I've been counseled against direct steam injection because of the "micro explosions" that occur when you inject steam.

Is this a concern for any of you that use direct steam injection for a hot liquor tank and has anyone had damage to their plant due to these "micro explosions"?

Not sure what you mean by Liquor tank?

The steam its self is non explosive. However steam pressure is. You cannot inject steam into a vessel that builds up pressure in the tank. It must be vented.Now if you heat up Liquor? then the vapors become very explosive. I use direct steam injection for cooking my mash. The tank is well vented so no internal build up of pressure in the vessel. When you inject HOT steam into a cold liquid you get micro explosions due to HOT steam coming in contact with a cold liquid. These are not burning explosions but a reaction of hot meeting cold. As the temp increases in the liquid you are heating this becomes less and less because the liquid gets hotter and hotter. If using direct injection of steam into anything it will be diluted when the steam turns back into water. The "Liquor" no matter what the beginning proof is will be diluted a lot. My mash runs gain 30 gallons of water at the end of the run. If you use direct steam injection for anything you will be putting things into what ever you are heating from the boiler and the water source. These additives are not good. It will change the flavor and aroma of everything and not in a good way. Coop

[absaroka]

Not sure what you mean by Liquor tank?

I think he means a hot liquor tank (HLT), commonly used in brewery operations as a vessel of hot water used for lautering grain.

[Daric]

yes. Thank you for clarifying. I'm just talking about heating water here. Your comments are very helpful. Does your pick heater add much water to your process? And since you're adding your boiler's makeup water to your mash, do you process the water feeding into your boiler?

[absaroka]

To answer your questions: yes, and yes.

Water added to what you are heating depends on size of boiler, length of heating time, etc. Water feed to our boiler is filtered, but not treated like a closed-system boiler. This will take some life off the boiler since you are adding new water to it as steam is lost, but your mileage may vary depending on your water source and how it is treated.

[coop]

I think he means a hot liquor tank (HLT), commonly used in brewery operations as a vessel of hot water used for lautering grain.

Thanks for clearing this up. When someone says liquor tank, to me it meant some kind of alcohol. Sorry for that. Coop

[meerkat]

Theoretically you need 0.002 kg of steam to raise the temperature of 1.0 kg of water by 1 degree C. Or 0.0011 lb of steam to heat 1.0 lb of water by 1 degree F. If your tank is not insulated and you are working at high temperatures there will be losses to the atmosphere as well. This will give you some idea of the amount of dilution you can expect.

The explosions are actually implosions - the collapsing described by ViolentBlue. It is exactly the same mechanism as cavitation in pumps. As the steam (or vapor in a cavitating pump) collapses it makes the noise and causes the damage or vibration. The bigger the bubbles the louder the sounds and the higher the risk of damage. I have seen 20,000 litre tanks trying to jump off their hold down bolts when using 10 mm holes. On the other hand, I have seen sparge pipes with 3 mm holes work reasonably quietly with minimal vibration.

Unless you have experience in designing these spargers I would recommend using a proprietary device like the pickheater where the supplier can properly size it to your application.