lawdawg
Chemical
- Jan 9, 2009
- 3
I am working on a Plant Expansion. We are making a product in a glass lined reactor. The product is inorganic. The temperature is about 280 at the end of the reaction. It is mostly an inorganic salt and water (about 50% water.)
To save capital it has been proposed
1. to evaporate enough water to bring the product down to its boiling point (about 235 F)
2. Then to bring it down to transfer temperature (about 10 F to 170 F) add make up water.
I don't think that this would pass permit review, but I am making my point around two points.
1. We need to vent off about 2600 gallons of water. That is about 545,000 cuft of steam. This steam will entrain some some product. We cannot have opacity greater than 20% for more than 6 minutes in this state for combined water.
a. If the vent down exceeds the sounders brown
velocity we will have entrainment (not total
flooding, but entrainment.)
b. The to keep the streams unentrained
(uncombined)we must below that venting
veloicty? Is this correct?
The equation I am using is:
Vsb=K*(RHOl/(RHOl-RHOv)^0.5
2. I also believe there is a hazard of charging cold water to the vessel at 230 F to bring it down to temperature.
a. The 2,600 gallons give about 350 cuft of vapor
space. The first ~1.5 gallons of water will
flash to fill the vapor space and we need to add
about 1,600 gallons to bring the reactor down
to 210 F. Then we can add the remaining 1,000
gallons.
b. If the reactor is blocked in I believe we will
experience steam hammer. this could damage
the vessels glass, shaft, agitator seal.
c. left vented to atm (through the scrubber) we
will be back with the previous problem of
sounders brown velocity limitations.
Where can I find an equation for the force created from flashing water in a closed vessel or pipe?
Do you concur with my analysis? Can anyone point me to supporting documentation for the hazards of flashing water?
I think we need to go with the original proposed cooling tower and tempered water exchangers to cool the vessel.
To save capital it has been proposed
1. to evaporate enough water to bring the product down to its boiling point (about 235 F)
2. Then to bring it down to transfer temperature (about 10 F to 170 F) add make up water.
I don't think that this would pass permit review, but I am making my point around two points.
1. We need to vent off about 2600 gallons of water. That is about 545,000 cuft of steam. This steam will entrain some some product. We cannot have opacity greater than 20% for more than 6 minutes in this state for combined water.
a. If the vent down exceeds the sounders brown
velocity we will have entrainment (not total
flooding, but entrainment.)
b. The to keep the streams unentrained
(uncombined)we must below that venting
veloicty? Is this correct?
The equation I am using is:
Vsb=K*(RHOl/(RHOl-RHOv)^0.5
2. I also believe there is a hazard of charging cold water to the vessel at 230 F to bring it down to temperature.
a. The 2,600 gallons give about 350 cuft of vapor
space. The first ~1.5 gallons of water will
flash to fill the vapor space and we need to add
about 1,600 gallons to bring the reactor down
to 210 F. Then we can add the remaining 1,000
gallons.
b. If the reactor is blocked in I believe we will
experience steam hammer. this could damage
the vessels glass, shaft, agitator seal.
c. left vented to atm (through the scrubber) we
will be back with the previous problem of
sounders brown velocity limitations.
Where can I find an equation for the force created from flashing water in a closed vessel or pipe?
Do you concur with my analysis? Can anyone point me to supporting documentation for the hazards of flashing water?
I think we need to go with the original proposed cooling tower and tempered water exchangers to cool the vessel.
