I have a potential small reactor design that will alternate between high pH (10% by weigh NaOH, so 14+ pH) that is later taken to a slightly acidic side with HCl, resulting in a 6-10% salt (NaCl) solution. The reactor temperature will be ambient, so no high temp conditions. I've reviewed some...
All,
A recent API 510 internal inspection of our pressure vessel has revealed some distressing information. The PV has a half-pipe jacket covering most of the sidewall. At some point in the past, internal pressure of the jacket exceeded MAWP by a fair margin, buckling the internal wall that is...
All,
We have manual ball valves in monomer service - styrene, acrylonitrile, arylic monomers, etc, that sometimes have severely short service life. After 6 months of operation in a blended monomer service (emulsion polymerization plant, so these monomers are blended with water, surfactants...
Does anyone have a reference to a means to calculate the maximum shear rate of a liquid being pumped through a centrifugal pump? We currently are looking at replacing a Sulzer pump with a different brand (Summit), and while the pump curves are very closely aligned and within the process needs, I...
I have a water remediation stripper than was used to strip out 1,1,1-tricholorethane as well as dichloroethane and dichloroethene. For the past few years, though, it has been turned off. The original design of this is nowhere to be found, so I'm having to reconstruct the design from bits of data...
Deleted the thread over at the valve engineering forum because it didn't get any responses...
We currently use Siemens 760 electropneumatic positioners for various control valves on the site. While they are generally reliable, I've seen a few issues with the valves. First is that the zero tends...
Background
I need to add some NPS 2" nozzle to the top heads of several Section VIII Div 1 pressure vessels. The vessels are older (1960s/70s) and have undergone a fitness-for-service (FFS) evaluation that de-rated them (from 50/75 psig down to 25-35 psig) due to a few thinner nozzles that did...
I have a situation that is a bit unusual. I have a need to weld two 3" nozzles onto a 24" B16.5 blind flange. The sketch is below; the design intent is to provide an enlarged portion of piping that would allow liquid monomer droplets that condense in the incoming stream drop out into the bottom...
We have a 3" butterfly pressure control valve installed on a cooling tower water recirculation loop. This valve is controlled to a pressure setpoint from a pressure transmitter located at the outlet of the cooling tower water pumps (combined header). The cooling tower water loop has a mix of...
I have been exploring addition of cooling baffle plates inside an existing pressure vessel. The addition of these plates would require new brackets to be welded to the sidewall of the vessel. We plan to do this in two parts - first, to weld the brackets on and put the vessel temporarily back...
We top off-load railcars of monomers and have been experiencing variances in our inventory management system on these materials. We recently compared tank level via gauge as well as stick measurement before/after emptying a railcar and found the storage tank to be light 700-1,200 gallons.
I'm...
This is sadly not theoretical. I visited a site a while back where an ~30ft tall storage tank was being “pumped” to an ~6’ tall effluent pH control tank. Between the two tanks is a 2” pipe with a small pump. I don’t remember the exact characteristics of the pump, but it was something like a...
The previous thread ( thread124-464517 ) is closed, so I'd like to give an update on this for those who are interested and helped out. This may be helpful for anyone who has to design thickeners for light or heavy particles in the future.
We trialed a low-speed disc-stack centrifuge...
I have been tasked with performing a facilities siting analysis of an existing facility that has a variety of pressure vessels on site. This task involves calculating the overpressure radius of vapor-filled vessels rupturing. Most vessels are 50 psig MAWP and under. I have no direct experience...
Details are scarce, currently. 2 were killed and many others injured after ~100,000 lbs of acetic acid leaked. However, another source has the Fire Marshall saying the leak was methyl iodide, hydrogen iodide, and methyl acetate, so there is even conflicting information on what actually leaked...
We have actuated ball valves, 2" NPS, in 70-90 psig (~315-335 F) steam service. The valve is a floating ball design, 2-piece, full port. It does not have any slow open/close mechanisms. Below are some pictures of the seats after only 6 months of service. These valves are actuated, on average...
I have a general question regarding MDMT in heat exchangers. Note that the scenario provided is theoretical, and is a situation that I would wish to avoid. However, I would like your input should I ever run across such a situation.
Consider a liquid-liquid heat exchanger. If the tube-side MDMT...
I have a pressure vessel that has 3 stamped dimpled jacket segments on it. The jackets are all rated to 150 psig. I'd like to walk through my initial sizing methodology and assumptions and get feedback on the assumptions and things I might have missed.
Dimpled Jacket, required relief rate
MAWP...
Can anyone point me to references that address interfacial surface tensions for emulsions, as well as any reference on shear rate vs particle size of the dispersed phase for emulsions?
All I can seem to find is oil/water-type references and measurements. I'm not sure physical or optical...
In reviewing the possibility of temporarily using an alloy 20 line for 85% acetic acid service, I noticed the corrosion rate was much higher than acceptable - 400 mpy at ambient temperature. This made me curious - what is the mechanism of attack on this alloy? Is it similar across other organic...
