Converting Ice in Steam on small Scale

[davidbestone]

Hello all,

I am in need of a device or a system that can covert ice/snow into steam on a small scale. My spacing requirements limit me to about a volume of 2.5' wide, 3.5' high, and 3.5' deep. Is there anyway to accomplish this?

Thank you

 

[MintJulep]

A kitchen stove and some tea kettles.

 

[IRstuff]

What's "small scale"

TTFN

FAQ731-376

 

[davidbestone]

Sorry I should clarify what I mean.

1. Small scale refers to size constraints of the system which are 2.5'x3.5'x3.5' as mentioned before.
2. This system has to be able to handle a 1 lb of snow/ice every 15 to 30 seconds.

 

[IRstuff]

Works out to about 83 kW average power, or 285 kBTU/hr. A typical stovetop burner runs about 15 kBTU/hr, which means you're talking about 20 or so stove tops, roughly speaking.

Maybe something similar to 3 or 4 of these:

http://www.rinnai.us/tankless-water-heaters/r98lse/

This seems on the hairy edge of not doable, at least, not in the volume you've specified. What's outside of this volume?

TTFN

FAQ731-376

 

[MrBTU]

Remember, snow is self insulating, so you would be helping yourself by compressing it first and getting all the air out....

 

[IRstuff]

I think that something custom will be needed. I would consider bulk of the volume to be available for insulation and heater for a central cavity of about a 1 cubic feet in volume. Run the cavity up to about 500°C, with lots of thermal mass, like a solid copper crucible with maybe 6inch thick walls, surrounded by insulation and heater.

The ice should be able to convert to steam nearly instantly, but you'll still need to make up the 83 kW plus about 20 kW of parasitic loss. The ice that's in contact with the crucible should flash into steam, which should also warm up the bulk of the ice that's not yet in contact.

Ought to be pretty spectacular in operation, one would think...

TTFN

FAQ731-376

 

[steamdog]

If you are serious you will need two items, an electric steam boiler and a heated condensate tank. You take the initial output of the boiler to a coil in the tank to melt the snow, then you pump the water into the boiler to make steam. Because the problem is that steam pressurized and there is not a practical way to get snow into the boiler.
Look at Sussman electric for the small electric boiler, and you can retrofit their boiler feed system with a steam coil in it.

 

[zekeman]

Why not use steam jets from the steam boiler to melt the snow in the holding tank.
But in the end you need
1 lb snow every 30 seconds
144*60*2=17,000BTU/hr
Certainly doable.
Your electric boiler firing steam into the jacket of the open
snow holding tank, water dropping to the bottom and pumped out some going to the boiler and the remainder to the output ,

 

[IRstuff]

Z,

Can you reverify your numbers? I have a 15kBTU/hr stovetop, and I can't even begin to boil 2cups of RT water in 30 secs, much less melt snow AND turn it to steam.

17kBTU/hr*30s = 1660W*90s, which is just barely enough to bring water to boil in a microwave oven, but it won't convert to steam in that time.

TTFN

FAQ731-376

 

[ione]

1 lb each 30 sec means 54.36 kg/hr of ice

Latent heat of ice = 80 kcal/kg which means 54.36*80 =4348,8 kcal/hr

Sensible heat (from = 0°C to 100 °C) means 54.36 * 100 = 5436 kcal/hr

Latent heat of vaporization (at atmospheric pressure) = 540 kcal/kg which means 54.36*540=29354,6 kcal/hr

Total thermal power required 39139,2 kcal/hr that is 154700 BTU/hr (no thermal loss from the reservoir taken into account)

If ice is at a temperature below 0°C it is necessary also to take into account sensible heat to heat ice (specific heat of ice cp = 0.50 kcal/kg)

 

[eadwine]

Produce Steam? At what pressure and do you need to add superheat? This is going to affect the size and design of the boiler & burner ass'y.. We know the input has been set at approx. 2-lbs of ice/H2O/Stm per minute or approx. 120- lbs of ice/H2O/Stm. per hr.

Now if you want to process "snow", this stuff comes in multiple mass varieties which affects its volume and melt capacity and thereby affects the size requirements of the equipment overall in order to handle the volume increases and the increased energy requirements to convert the snow/water/stm.

Good luck trying to fit this equipment into a 2.5'x3.5'x3.5' envelope.

 

[zekeman]

Stuff,
My bad- left out a few numbers namely heatup to boiling and latent heat, especially the latent heat
Should be
(144+180+1000)*120=158,800 BTUH
an error of only factor of 10.
Project not so doable in 2-1/2 feet of space.
Try thermonuclear.

 

[FredRosse]

Getting a 200,000 BTU/hr furnace (Oil or Gas fired) into 2.5ft x 3.5 ft x 3.5 ft space is not a technical challenge. What we are talking about here is a typical house heating hot water boiler, house heating LP steam boiler, etc. These easily fit into the specified space envelope.

What is the purpose of the device, why steam, how is the snow fed to the boiler?