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Dears I would like to have a confirmation here: Suppose I have 1000 Nm3/h of gas containing 75% vol of hydrogen (or around 2% mass). If I want the flowrate of pure hydrogen in Nm3/h, shall I multiply by the hydrogen mass fraction or volume fraction? TO me it is clear that Nm3 (standard volume)...

Good day, I am researching the EN ISO equivalent to: API 650: storage tanks API 2000: atmospheric storage tanks API 560: fired heaters API 660: shell and tube heat exchangers API 661: air-cooled heat exchangers API 674: positive displacement pumps, reciprocating API 675: positive displacement...

Hello everyone I was wondering if there is any standard or recommended practice regarding typical alarms and trips to be implemented around centrifugal pumps? The reason is: in the refinery I am working in, I see plenty of alarms and trips that I don't see the purpose. For exemple, on pumps...

Hello The performance of one of our shell and tube heat exchanger has changed in a significant manner. The service is crude oil in the tubes and diesel in the shell. It has 1 shell pass and 4 tubes passes. Tube side equipped with turbotal Surface is 197 m2. Before a shut down, performance...

Dear members, I need to know the industry standards that deal with the calculation of tank volume based on the level in the tank, and the procedure to correct that volume from temperature effect, roof type,...? Thanks in advance. "We don't believe things because they are true, things are true...

Hi, Maybe the answer is obvious but I have read contradictory opinions on this subject. Does H2 increase or decrease the lower heating value of a Fuel Gas composed Of C1/C2? In other words, is it a good thing to have H2 in a FG? I ask the question because, when expressed in kcal/kg, H2 has a...

Dear all, Maybe an easy question for you: I have a steam-turbine driven centrifugal compressor with the suction drum pressure-controlled. There is a vent valve (to flare) on the line between the drum and the compressor. What happens of I open the vent? - will this lower the suction pressure...

Hi, What is the effect of liquid density on: 1/ Centrifugal pump's hydraulic power? 2/ AC motor amperage load? Thanks. "We don't believe things because they are true, things are true because we believe them."

Hello, We have a gas turbine + alternator generating less power than expected (design). I have noticed that the actual Current and Cosphi are different from the design values. DESIGN: - Air temperature = 15 degC - Cosphi = 0.75 - Current = 687.8 A - Active power = 4.9 MW - Alternator...

The bonnet of bellow balanced Relief Devices shall not be plugged, because in the situation of a leaking bellow, you will get an unwanted situation that the opening pressure increases with the backpressure. Disadvantage is the situation of a leaking bellow is that you will have the product/gas...

Dear alk, I plan to make some orifice flowmeters of my refinery checked, during the next shutdown. I was wondering if you could share your experience and knowledge regarding the "things" to be checked to ensure optimal accuracy of the existing orifice flowmeters? Also, what documents shall I...

Dear members, Probably an easy question for some of you but, as I am not an instrument technician, I would like to have your views. The issue is that for several orifice meters in my plant the range is not the same in the instrument specification sheets and in the DCS. For example, ranges...

Hello, Could you please help me clarify the differences between the following terms: - range? - span? calibrated span? - full scale? - Max DP "We don't believe things because they are true, things are true because we believe them."

Hello, I'm not an instrument guy but I have a question concerning the application of correction factors to flow measurements. During actual plant operation, operating conditions may be significantly different from design conditions (density for liquids, and T, P, Z and molecular weight for...

Hi, We use superheated steam (+150 degC superheat) as live steam in a SWS. I was wondering if using saturated steam would significantly help reducing the bottom temperature? My theory is that steam traffic will decrease, thus decreasing the pressure drop in the tower, the bottom pressure and...

Hi, I was wondering how to correct gas turbines shaft power for actual conditions, given that the manufacturer communicates a power at reference conditions (typically 1013 mbara and 15°C)? Are there any standard charts or correction factors formulas that I could use? The gas turbines in my...

Hi, In my plant, we need to buy a flowmeter and I have difficulties to determine the minimum flowrate in the line. Indeed, data retrieval software always gives "zero" as min flowrate. So I was wondering: - Is it mandatory to specify the minimum flowrate in the process data sheet of a...

I would like to know what operating variables process engineers do (or should) monitor in your refineries, in order to follow the performances of the following units: 1- Atmospheric distillation 2- Semi-regenerative catalytic reforming 3- Naphta HDT 4- Kerosene HDS 5- Gasoil HDS Thanks "We...

Dear pros, I used to believe that either Positive-Displacement or Centrifugal type pumps (and compressors) create flow and not pressure. That is, they conform their discharge pressure to the process' total back-pressure at their discharge flange. Now I have come across a serious article from...

Hello, In my refinery, we mix 45% jet + 55% medium gasoil (320-350°C) to fabricate what we call "combustion gasoil". The constrainst are: - maximum viscosity at combustion chamber entrance:6 cst @ 40°C. - Maximum water content: 0.1% vol. - Maximum sulfur: 0.8 % wt. Now the following has been...