I'm revaliding a PHA for a med/high (100-500cp) plant.
We are going through the cases and taking credit for the positive displacement pumps spill back valves for preventing down stream vessel damage in a lock in case.
The problem I encounter is that almost all of them on the high viscosity...
What is other users experience for gas phase pressure drop in Aspen using the pipe block. And, under deep vacuum ?
We have a system with HX's and Pipework under deep vacuum so the condensation thermo impacts the flow rates etc.. so using aspen is very attrative.
Aspen users the darcy...
I’ve been made aware of a paper on Flash point predictions for binary mixtures. Which describes systems with mixture flash points that can be 10-15 C lower than the pure components within the mixtures. These are for non-reacting systems, I am aware of systems which react with air and then form...
All,
maybe this sounds a daft question but i'd like some feedback on the following..
if you are using 150psig steam on a reboiler, usually you control flow to the reboiler with a CV, then the pressure drops on the steam, velocity rises..
so, if you assume 150 psig for all these case you dont...
The purpose of this question is to understand partices used for operating pressure Management of change and relief load evaluations.
For a gas filled vessel the relief rate / ultimate pressure rise depends on the start pressure (e.g.) how much gas is present at the start. So. From a relief...
The purpsoe of this is to understand peoples conventions on this.. generally it does'nt impact the calcs but on a revalidation i'm doing it is close to needing a new valve.. so i'd like some input please..
So, when you size for the fire case
Q= FA^0.82 : Fire duty = Q/ Latent heat.
Is the...
I'm looking for some standard pratice or recommendations for handling relief cases when we have a utility which could over pressure the process side from leakage inwards.. but it is not a shell and tube...
so for a spiral HX on process water , or a carbon block are there any guidelines for...
Dear all,
sounds an odd question..
what is the guidance for min distance to avoid erroision from an anti suphon hole to the vessel wall? i've heard of an incident in the 90's at my site that at vessel failed after 20 years service from this but unfortunatly we have lost the incident and...
I'm looking for a reference for typical civil design codes and why vessels at certain location use an SG of 1.5 when the process fluids are typcially 1 or much less than that...
When we have tracked back in our records 1.5 seems to have been what we have always used and probably for good...
sorry for a short question.. I'm struggling for a decent reference for the L/D for standard 3 way valves..
I normally use 1 eblow and a valve, which is conservative but on a recent calc I exceed 3% inlet line losses on an RV. So I'd prefer the calculations to show less than 3% so I dont need...
I'm looking for some overall reference for guideance for when it is economic to split a column into two or when you just make the design MUCH taller..
For example when you have a 1.8 meter 60 meter tall and want many more stages:
> is it still economic to go for 80 meters by 1.8...
Dear sirs,
Running the heat exchanger sizing program to increase flow to an operating BEM Exchanger I've noted that if we increase the flow beyond a set range it exceeds TEMA rho v2 values on the shell side.
I've looked at the mechanical design and it is not possible to fit A large inlet...
I'd like a quick check on methods for fire area that should be used under API521 to get overall duty..
I believe if we have a system with two vessels the correct way to consider fire load is as below.
method 1: Q (Total) = 43.2 * F* A1 ^0.82 + 43.2 * F* A2 ^0.82
method 2: i believe this is...
I've a question about Tube side tema values. and does it really cuase issues..
if you consider a Heat exchanger diameter 600mm, nozzle size inlet 200mm. if you get tube side rho v2 values does really cuases issues becuase it does'nt on the inlet pipe, most HX the fluid turns 90deg on the inlet...
All,
I'm looking at increasing the capacity of a air cooled heat exchanger - i'm aware sonic fog / mist sprays have been used to increase capacity.
I'm looking for users feedback on how well these have worked.. and have these damaged HX tubes.. or cause legionella concerns..
Dear all,
I'm valiading if we drop the opperating pressure on a deep vacuum condenser if we will damage the exchanger. Aspen EDR suggests vortex shedding amplitude and turbulent buffeting issues. It says possible in some and defines them for other points on the shell the magnitudes are 1200...
We are looking at replacement of an air cooled exchanger on site, and i've been asked to considered a coating on the fans to reduce air side fouling..Heresite is the name..
what is users expereince with those..
(we are near the coast..)
i've not seen my company use these before..
We are evaluating flammable gas detection to take proactive action following a flammable leak of fluid at 340 C, under pressure.
Is anyone aware of the use of thermal cameras to detection a leak and activate say a deluge. As such keeping room temps below the flash point would prevent a flash...
I'm looking for advice on Rules of thumb on column sump design (and making sure i've not missing anything key)
I am looking at the basis to reduce the liquid volume in a column sump for safety reasons my system is a packed column without reboiler feeding another column which is trayed. These...
I'd like some perspective on setting of design p's for tall columns which are linked..as i approach a re-engineering exercise on a proces design..
col 1: RV P 100 Psig top
Col 1 bottom Design P = Pressure from (Tray liquid loading at flood) + Pmax liquid level in sump + P margin.
Col 2,
Ptop...
