flash vessel, flash tank, flash steam, flash steam recovery

[tadream]

hello

i've been looking all over the internet to find out what it is to no avail. finally, i've stumbled upon this group.
please give me a short description on the above topics and most of all to the question 'what is flash'?

thnx a lot in advance.
adam

 

[25362]

This is what I extracted from a technical dictionary in a chemical engineering context:
Flash is defined as a rapid vaporization achieved by passing a volatile liquid through continuously heated coils or by pressure reduction (vacuum).
Flash vessel = flash chamber = flash trap, mostly refer to an oil-and-gas flash separator operated under vacuum where the entering liquid flashes into it.
Flash drum is a facility such as a tower or column that receives the product of a preheater or heat exchanger to relieve pressure; volatile components are vaporized and separated (sometimes) for further fractionation.
Flash tank, a unit that is used in a processing operation to separate liquid and gas phases.
Flash steam is steam produced in a boiler (=generator) with hot tubes of small capacity designed to immediately convert small amounts of water to mostly superheated steam.
There are many connections with "steam", but I didn't find any on recovery of flash steam.
It may refer to the act of recovering flash steam from water-containing liquids.

 

[krsmani77]

My views: From high pressure steam condensate/blow down systems, one can recover steam at low pressures by flashing the condensate in successively lower pressure flash drums, which separate vapour from liquid with minimum carry-over of water/condensate with the steam. Such flash vessels can have internals for better vapour-liquid separation. The bottoms of hi pressure flash drum goes to the low pr flash drum under level control and further flashed. This way a lot of heat from the hi pressure condensate is recovered.The flash drum vapour lines except the last atmospheric one, are connected to the corresponding pressure steam headers.

 

[quark]

When high pressure condensate (before steam trap) comes to a low pressure (relatively) ambience, some quantity of condensate gets vaporized. (as the condensate is at saturation temperature with respect to some pressure and as you are lowering the pressure it's boiling point reduces)

This can be utilized for low pressure applications.

Download this for further details and design.

http://www.armstrong.be/pdf/N_101.pdf

Check also website of Spirax Sarco.

 

[tadream]

thanx a bunch guys! this really cleared up some twisted expressions with 'flash' word in them that i had to deal with.

 

[abilalz]

ABILALZ (CHEMICAL )

Flash means lowering of Boiling point due to decrease in system pressure, mostly used to produce steam by let down of condensate from high pressure to low pressure