8 replies to this topic

[EnerJack]

I read some articles on steam compression to upgrade quality (Pressure-Temperature)with dollar savings calculations. It looks nice in theory but I wondered if anyone had experience with installation and operation of such equipment.

Im investigating the possibility to take 10-25tons/hour of 25 psig steam and recompress it to 140psig.

Any ideas?

Thanks

[joesteam]

If you compress saturated steam - you get water. You must have superheated steam so that the higher pressure does not condense the steam. You did not mention the temperature of your low pressure steam in your question, but it must be higher than the corresponding saturation temperature at the higher pressure.

[katmar]

The easiest way to compress the LP steam is to use steam at a higher pressure than your target pressure in a venturi thermocompressor. This is very widely done and I (and I am sure many others here) have done this successfully.

The equipment is cheap and reliable, but requires considerable experience to design successfully. Have a look at the Graham Manufacturing web site for info
http://www.graham-mfg.com/default.asp

[EnerJack]

If you compress saturated steam - you get water. You must have superheated steam so that the higher pressure does not condense the steam. You did not mention the temperature of your low pressure steam in your question, but it must be higher than the corresponding saturation temperature at the higher pressure.

Thanks for your reply joesteam,

I attached the file from the US Department of energy. They don't imply the need to have saturated steam, they even suggest to add a spray of water to eliminate superheat. The fact they post this article in the "industry best practice" I supposed it was a known process but my internet research on the subject did not give me much.

Your comment on saturated steam is thermodynamically correct but in the mechanical compression of air, most of the hp consumed by the motor is transfered in heat to the system. Maybe this would compensate for the saturation issue.

Attached Files

•  steam11_waste_steam.pdf   220.52KB   136 downloads

[EnerJack]

The easiest way to compress the LP steam is to use steam at a higher pressure than your target pressure in a venturi thermocompressor. This is very widely done and I (and I am sure many others here) have done this successfully.

The equipment is cheap and reliable, but requires considerable experience to design successfully. Have a look at the Graham Manufacturing web site for info
http://www.graham-mfg.com/default.asp

Thanks Katmar,

Thermocompressors was my plan B. I do not have much details since I haven't visited the plant in question. I am still compiling all available technologies before answering to the customer. Thermocompressors do need higher value steam to operate and I do not know what they have available now. I was interested in the mechanical compression since the article from the US department of energy mentioned it as a best practice.

Regards

[joesteam]

I am not expert on this, did a quick Google of 'Mechanical Vapor Compression', and the equipment uses an external energy source (electric or higher pressure steam) to reboil the water that condenses due to the higher pressure. You can't fool physics, saturated steam will condense at any pressure increase.

[Zauberberg]

I am not expert on this, did a quick Google of 'Mechanical Vapor Compression', and the equipment uses an external energy source (electric or higher pressure steam) to reboil the water that condenses due to the higher pressure. You can't fool physics, saturated steam will condense at any pressure increase.

By compressing 25 psig saturated steam to 140 psig, the final temperature will be somewhere in between 305-325 degC, depending on compressor efficiency. Do we miss something here?

[Jenergy]

These days, steam compression is necessary following vacuum evaporation occured from waste heat recovery. When compressing steam, adiabatic-close compression is expected, and saturated state becoms superheated high temperature, high pressure state. So cooling system is needed to protect compressor.

MVR(Mechanical Vapor Recompression) is done by turbo-compressor(=centrifugal type), however, multi-stage compressor is usually required.

Here in Korea, Samsung Techwin - air compressor manufacturer - initiated manufacturing steam compressor.

Anyway, you'd better look up MVR systems.

Edited by Jenergy, 13 September 2010 - 09:28 AM.

[Padmakar Katre]

Dear,
I hope following links may help a little,
http://www.spilling....ompressoren.php

http://www.energysol...compression.asp

http://www.thomasnet...17251604-1.html