3 replies to this topic

[shpereira]

I have a super critical CO2 plant. Twice a week, boiler undergoes cleaning and hence steam is cut off for 4 hours a week. In order to avoid steam cut off, is there any other method I can use to keep temperature of 4000m3 of ordinary water at 45-55 deg C by using a safe, shock proof system? The water is recirculated to a double pipe heat exchanger and hence I need to maintain hot water inlet supply. Should be cost effective and safe too. Thanks Sharon

[shan]

Buy a back-up boiler.

[Art Montemayor]

 

Shpereira:

 

I don’t understand what you mean by “a super critical CO₂ plant” or the importance of having 55 ^oC water constantly available.  But I think I can guess: you produce a stream of supercritical CO₂ for either transport purposes or for processing the oils or other ingredients from a mixture by selectively dissolving them in the SC CO₂.  Either way, you must ensure that the CO₂ is kept in the SC state and for that you need a constant heat source.  You normally use saturated steam to heat the CO₂ and are looking for an alternate method.

 

What I would do is identify the RATE of heat transfer that you need.  You haven’t told us that and it is the measure that is of most importance.  To find that out, multiply the flow rate of CO₂ that you have above the critical pressure (approx. 980 psia) by the enthalpy difference of it at that state and the heated state that you need to ensure that it is supercritical.  This heat load capacity will indicate to you the relative size of the method you need to heat up the flowing stream.  If if is relatively low, you might be able to justify an electric immersion heater – such as a Chromalox type.

 

If you don’t know how to do the calculations, tell us:

1. The flow rate of your CO₂ stream;
2. The cold state of your CO₂ (the pressure and temperature);
3. The desired heated state of your CO₂ (the pressure and temperature).

[ramsingh_mech]

Is it a chemical cleaning?, what type of cleaning your boiler required(twice a week) , is that type of cleaning cant be be operate online??? (Online cleaning- You can clean your boiler parts online while running with out shutdown). 

Edited by ramsingh_mech, 05 April 2013 - 12:15 AM.