What cooling method to cool 600K air at 650kPa?

[kilok9]

I am designing a cooler to cool air 10 cubic meter/second at about 600K at 650 kPa to about 290K at the same pressure. this is from an air separation plant. i would like to know what type of cooling method can be used. and also how do i carry out a chemical engineering and mechanical design.

Thanking you in advance

best regards

 

[TD2K]

Well, you are talking about cooling from 327C down to 13C.

You can likely cool down to about 60C with air coolers using ambient air (below that temperature, air coolers tend to become more inefficient wrt the amount of surface area they need). From there, you could cool down to perhaps 25C or 30C with cooling water if that is available. Down to 13C, you are going to need a refrigeration loop. You can also combine the water and refrigeration coolers but that increases utility costs.

You know the flow rate, I'd take a look at what sort of duties those temperatures work out to. For each exchanger though, you are going to need to allow for some dP, at least 35 kPa on the air side, perhaps closer to 70 kPa. Pressure drop means turbulent flow and that minimizes the area and the cost of your coolers.

 

[25362]

The data you provided seem to point to the fact you intend to precool the air ahead of the cryogenic air separation processing steps. In that case you are after a heat exchanger between the given air and the plant's effluents.

Present day high-tonnage air separation plants use a combination of expander and J-T refrigeration to deep-chill the precooled air. Moisture and CO₂ are removed in the process.

To better understand the chemical engineering efforts needed in designing such a plant, or parts of it, I'd suggest you look to existing plants and take good note of the type of exchangers used, the materials of construction, and the criteria for their selection, the preferred thermal insulation adopted, as well as other equipment and instrumentation details.

I hope I've been of help.