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Dear all In a Steam Cracking unit there are Sulphur spec for feedstocks. However sulphur mercaptans don't have, at least at the majority of the plant I know, specification. Do the sulphur mercaptans crack? Are they converted to H2S completely? Are they totally inert to the caustic scrubbing...

No gaskets since the piping is welded. We did X-ray 100%, penetrating liquids test and pressure test at 500 mbar with air. It was accepted by authorities. Vacuum test to be done in startup of the ACC AndreChE

Dear all We have recently switched 3 complete cells of our Air Cooled Condenser system. The old ones were cut and new ones were welded. The test that is being done (before plant startup) is a positive leak test. We pressurize the system up to 500-700mbar (design pressure) and check pressure...

Dear all We have recently switched 3 complete cells of our ACC system. The old ones were cut and new ones were welded. The test that is being done (before plant startup) is a positive leak test. We pressurize the system up to 500-700mbar (design pressure) and check pressure loss. However...

Yes, agree. It's not a book reading I'm looking for. I was comissioning engineer for two projects in "my" plant but now I'll be the comissioning manager for the ongoing project. However, my experience is only Steam Cracker. In fact I always disagree on several things in the previous manager...

Dear all I would like to have good information regarding Process Plant Comissioning & Startup. I will be deeply involved in a Steam Cracker major revamp. I already have the book Process Plant Comissioning but I would like to study and compare different approaches. It's not our first big...

Dear all I would like to have good information regarding Process Plant Comissioning & Startup. I will be deeply involved in a Steam Cracker major revamp. I already have the book Process Plant Comissioning but I would like to study and compare different approaches. It's not our first big...

I cannot find any function with Temperature and pressure as independent variables...

Dear all Does any know, for ethylene and propylene, the h(T,P) function without chart/table interpolations? I'm doing an energy balance to put in the DCS to the operators regarding centrifugal ethylene and propylene compressors. Since the first stages discharges are internally mixed with the...

Dear all Does any know, for ethylene and propylene, the h(T,P) function without chart/table interpolations? I'm doing an energy balance to put in the DCS to the operators regarding centrifugal ethylene and propylene compressors. Since the first stages discharges are internally mixed with the...

In fact I was again outside in the plant studying possibilities and then I realised the obvious... In these 160m, I have an heat exchanger that cools down my gasoline to be pumped. This HE works in fact as a buffer and the suction line lenght I should consider is not 160m but around 30m. With...

We have pulsation dampener in the suction and discharge of the pump.

Ok, I understood everything except the most important. With a NPSH of 84m (as centrifugal pumps) and a calculated acceleration head of 89m, my pump as pulsation dampener. For a 4m required NPSH will the pump work without vapour space or not? Does in fact this acceleration head reduces my +84m...

Use AspenHysys or AspenPlus

The final ethylene storage, for example, at the harbour is at -104ºC. Intermediate storage is under pressure, depending on the consumers processes. However, you cannot storage at exact atmospheric pressure, you need to control its pressure around 40-60 mbar above atm pressure, giving enough DP...

I agree with you when you say "requires some additional compensation in the form of a slightly higher NPSH requirement when compared to centrifugal pumps". Analysing API 674 and Pump Handbook, due to the lenght of the line the NPSH get negative which I don't understand (don't believe!!!)...

Dear all I'm having some difficulties to understand what in reality is acceleration head. I'm designing a system to pump hydrocarbon (gasoline) to another header with a reciprocating pump. Without acceleration head calculation I have a NPSH of 84m. Considering it I have -5m because the line...

The original code is ASME Operating pressure will be 4.6 barg The portuguese jurisdiction regulates pressure vessels. Regards, AndreChE

Dear all I'm a chemical not mechanical engineer... How can I re-rate a heat exchanger to change its design conditions? Actually, design temperature s 150ºF but this is the operating temperature of the new service. See thread 124-195840 Regards, AndreChE

Sorry...what do you mean with rerate the exchanger? Submit new design conditions to local authorities with an independent organization qualification report? I already had that in mind...