Okay, thanks for reminding me-the rundown tank is only meant for emergency cooling of bearings during a total stop.
Drawing shows no check valve or trip valve on the rundown line leading into the main oil supply, so what stops oil from reversing into this rundown tank in normal operation ...
Strange, are those "N2 bottles" these bladder accumulators ?
And your rundown tank appears to be on gravity based feed into the lube oil circuit - the ones I've seen are pressurised rundown tanks.
If the rundown tank level is low in this gravity setup, then the feed pressure at the lube oil...
Is combustion flue gas on the shellside ? If so, there may be contaminants in the fuel oil that are not compatible with the shellside material. It may be due to H2S, resulting from incomplete combustion of traces of sulphur in cheaper grades of fuel oil. Condensation of the flue gas on the shell...
Its a buddy racket with the Engineering Council UK / I Chem E / I Mech E / I E E/.... and this a much larger operation. Heaven knows where all this money goes....
For starters, take a look at differences in vapor pressure, density and viscosity between these 2. Presume this is a re run storage tank that may be used for storing cold start hydrocracker product also, so there may be a wide range in these physical properties to be considered. What is normal...
Are you injecting some kind of ammonia solution upstream of electrostatic precipitator for corrosion control ? Some months ago, there was a posting on E tips about problems related to amm sulphide caking up in the ESP. Could these whitish fumes be amm sulphide / amm sulfite? Ammonia reacting...
Apologies, my earlier response is incorrect. For liquid thermal expansion case only, Q, U and LMTD will be considerably different, since flow will be much less than design case. Flow may well be laminar inside the tubes ( or may be natural convection depending on limiting case Reynolds number)...
U and Q will be much lower with PSV on tubeside inlet, since the flow path to the PSV almost completely does not pass through HX. As you said, flow in HX will be almost stagnant - it will be in natural convection mode.
a) If this LPG remains in liquid phase at relieving pressure, then design duty can be used as heat input
b) If the PSV is located on the LPG exit side of this HX, and given that Cp of LPG liquid will remain the same at relieving pressure, it is likely that LPG exit temp to the PSV will still be...
Rather than work out what T_isen will be at 360bar with a constant Cp/Cv or gamma value, given the large compression ratio, it would be better to read off what T2 will be with a T-S diagram for O2 - see fig 2-15 on page 2-263 in the 7th edn of Perry. So you dont have to worry about Cp/Cv and Z...
Its probably safest to use the lowest operating steam pressure that will enable gentle heating with less risk of thermal decomposition on the inside heating surface, and that will keep batch heating time just about acceptable.
Steam pressure at the jacket will also influence the safety relief...
There are 2 or 3 requirements for such ROs':
1) As other have pointed out, it acts to limit the gas blowby rate to be no more than the vapor handling capacity of the downstream vessel. Check if there is a possibility that 2 dump valves may be in operation at the same time.
2) It also slows...
In steam heated heat exchangers where steam temp is lower than process fluid temp, there is a risk of migration of the higher pressure process fluid into steam due to corrosion / pinhole leaks on tubes and seepage through tube to tubesheet joints. De aeration / degassing helps to vent off these...
If the skin temp on the reactor side of the jacket is too hot, you may have thermal decomposition of the reactor fluid. If this concern is valid for your application, adjust the steam temp to be below what corresponds to this limiting skin temp. Calculation of this skin temp may be complicated...
Google says typical suction lift for a gear / lobe pump is about 8m, and you wont need a foot valve in the suction line. Ask the pump vendor if the pump can dry for say a minute or so until the pump casing is filled with liquid.
As shown, this pump will work as intended only if the suction line is fully primed with liquid. Only then will it be able to lift this liquid from 40cm below. Some types of pumps in this service have auxiliary positive displacement pump that operate for a short while on startup to pull this...
You normally dont use the PSV for this emergency "dumping". Use a dedicated depressuring valve which is forced full open through the plant's safety controls. The emergency flow through this path is constrained by a restriction orifice or by selecting a globe type valve as the depressure valve...
