CO2 heater/vaporizer

[PetroBob]

I'm replacing an existing (~20 years old) CO2 heater used to heat CO2 from a bank of gas bottles. I would think this must be a standard item but I can't find any information about possible suppliers. Can anyone can name a suitable supplier or suggest how to find out? Perhaps I'm googling using the wrong words? No luck with "CO2 heater" or "CO2 vaporizer" (US or english spelling).

The existing CO2 heater is approx 1 ft diameter x 2.5 ft long, somewhat like a shell and tube exchanger with CO2 passing through the tube side, the shell is filled with water heated by a 20 kW (27 hP) electric element, and is used to vaporize CO2 from a bank of gas cylinders (to prevent the CO2 freezing due to sudden pressure drop). The CO2 is regulated (downstream of the heater) from 770 psi to 150 psi.

It's working fine, but there is a concern that it might fail due to age, and it's a critical bit of kit for safety and operation of the plant (CO2 purge of flammable gases). It's used reasonably often (once a month or so).

I found this thread which was very interesting and useful (but didn't name any suppliers):

http://www.eng-tips.com/viewthread.cfm?qid=145412

I'm downunder (New Zealand) but would consider importing a standard CO2 heater from US or Europe since it will cost a lot to get it custom made here. I'm interested in any suppliers from any country.

 

[bimr]

Maybe this firm can help you:

http://www.tomcoequipment.com/

 

[PetroBob]

Thanks bimr, I had a look and they might have something suitable.

A thermodynamics question for any technical folks out there:
I have 0.226 kg/sec of pure CO2 coming from cylinders at 55 bar and 15 degC, heating it up to 60 deg C (or thereabouts) at constant pressure, and then flashing down to 10 bar. I calculate this will result in CO2 cooling to about 17 degC and require energy of about 6 kW. I calculated the 6 kW simply using enthalpy of the CO2 at original condition in cylinders (55 bar/15 degC) minus enthalpy at final condition (10 bar/60 degC). Is this the correct approach? (I don't have HYSIS or other simulator unfortunately.)

(I know it's simple, but I haven't done any thermodynamics in many years)