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Questions tagged [process-engineering]

Process engineering focuses on the design, operation, control, and optimization of chemical, physical, and biological processes.

88 questions
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Sizing a pressure safety valve for two-phase flow

I understand that valves in two-phase vapour / liquid were sometimes sized by considering the required vapour and liquid flow rates separately, and then adding the results together. But this is now considered an outdated practice. I have also heard…
SecondVector
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Can we change steel properties by application of magnetic field while quenching?

Austenite is non magnetic while $\alpha$-ferrite and pearlite are magnetic. (Magnetic properties of pearlite vary as a function of carbon content) If a strong magnetic field is applied in a particular direction while the steel is being quenched…
Subodh
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Recommended models for mineral liberation in crushers

I'm investigating comminution processes at work, and from my studies I know that there are different breakage models for different modes (Compression, attrition, fracture etc). So far I have only seen population models for ball mills in use. These…
MMerry
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External diffusion: calculation of surface concentration

I am struggling a bit with an external diffusion problem. I am trying to calculate the concentration at the surface (as well as surface reaction rate) and would like some help or guidance. Here is what I have thus far. The reaction taking place,…
Mierzen
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Steam sterilization of whey in a bioreactor

I'm trying to design a bioreactor to produce citric acid with whey and Aspergillus Niger. The first step in the process would be to put whey into the reactor with some dextrose (approx. 10%). Then, this solution should be sterilized, and I was…
Pepe Mandioca
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In the context of a known disturbance $d(t)$ in a control loop, what is the $\Delta t$ at which the control loop has to be executed?

As an example, consider a P-T1-system with a PID-controller. First look only at the P-T1 system, set a $y_r$ and wait a long time - then we take a look on its output $x$ and see that it has still a disturbance $d$ which variates with time (see the…
JHK
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How can I measure the thickness of a sedimentation layer in a closed tank?

Biogas slurry often contains sand and grit and organic matter that eventually sediments. Clearing thetank from sedimentation is expensive (plant downtime, additional equipment) and dangerous. So it would be interesting to know how much sediment…
mart
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Block diagram vs flow chart?

I was studying a book on control systems where I read that a block diagram is a specialized high-level type of flow chart. What is the difference between a normal flow chart and a block diagram?
DSPCS
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What is a PD pump that I can use as an immersion pump for a slurry?

I need to pump a thick slurry from a tank. The slurry can be pumped, but won't flow well enough that I can use a suction pump from outside the tank. Normally, I'd use a centrifugal immersion pump that can be drawn from the tank for service. But with…
mart
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How to optimise feed-forward control of a process based on a prediction using the prediction confidence?

I'm looking for a control method for a production process with the following characteristics: 1 control variable many process parameters (+-50) 1 resulting variable continuous measurement of resulting variable with 30-90 second delay complex…
marqram
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Does every engineering design needs to have a complete theoretical backing or may experimental data suffice?

This may sound rather vague on its own so I will explain with examples. The solid booster rockets used by NASA space shuttle used a central bore design because it had a certain characteristic on burn rate and thrust. If this data was to be…
Allahjane
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Working Out Shaft Torque in a Stirred Tank with a Cylindrical Cavern Formation (using a non Newtonian fluid)

Here is some background to the problem (in a stirred tank): "With yield stress non-Newtonian (viscoplastic) fluids, it is possible to generate an agitated volume around the impeller, defined as a cavern, surrounded by a stagnant region where the…
MathsIsHard
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Baffle vs Bottom Temperature Measurement/Control

In an industrial jacketed reactor, we have two temperature probes: one on a baffle the extends down about to the 50% fill line one built into reactor, very close to the bottom valve. When is it more reliable and practical to use one location…
tralston
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What's the difference between annealing, curing and sintering?

All these processes sound like structural change caused by heating.
Sparkler
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What is the correct pipe size for a 2inch pipe?

I'm was looking into the ASME B16.5Pipe flanges and pipe fittings and it has 2 dimension tables metric and inches. What I found was rather strange for me. I was looking at a 2 inch welding neck flange, and the hub diameter must match the pipe…
Mech_Engineer
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