Mechanical Vapor Recompression

[DMcMahan]

We are considering vapor recompression to upgrade the heat quality of a waste vapor stream so that it would be easier to integrate with existing proceses for heat recovery. I am looking for information on pros and cons of this as well as what issues may prevent this technology from being applicable.

 

[UmeshMathur]

Usually, you'll have to run a centrifugal compressor, with a suction surge drum, to enable this strategy. If the loads are variable, you'll need a variable speed driver, such as a steam turbine. There are the usual mechanical reliability issues with rotating machinery. Also, you'll need to think carefully about anti-surge controls to protect the compressor against very low inlet flows.

The economic justification would require a careful analysis of the net present worth of the installed hardware versus the economic value of the heat recovery, after deducting the operating costs of the compression system.

 

[rmw]

If you have the vapor at a higher pressure and you are letting it down through a pressure reducing valve anywhere in the system, then you might want to consider a thermocompressor.

If you are interested in this approach see

http://www.graham-mfg.com

rmw

 

[rattler2g]

Does your plant use a cogen power plant? We installed a two of these and they required 1,500 hp motors. It is only cost effective is the cost of electricity is less than the cost of generating steam. At a cogen facility it probably will not be economical because the extra electrical load will require more steam to be generated.

Like rmw said, you may want to consider thermorecompression.