Questions tagged [process-engineering]
Process engineering focuses on the design, operation, control, and optimization of chemical, physical, and biological processes.
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Custom User Models in Aspen Plus
I'm trying to simulate a purifier in Aspen Plus in a cryogenic system. This purifier is just meant to change the pressure of the outlet stream based on the inlet flow and pressure (we are using the ...
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1answer
43 views
Modelling reactor jacket with or without insulation, how to proceed?
I am currently trying to derive a model to help estimate as precisely as possible how much time can be saved by insulating the jacket of a reactor used for eating and cooling.
EDIT: I edited my post ...
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When teaching separation processes, which one should be introduced first? Distillation or absorption?
I am preparing a basic course on Separation Processes (5th semester, BSc Chemical Engineering). I can see that many well-known textbooks (e.g. Seader & Henley, Wankat) start by teaching in detail ...
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Entrainers to distill MTBE from Methanol? - Chemical Engineering Question
What have you found to be some effective entrainers to distill MTBE from Methanol, given the azeotropic conditions at 67%. I have tried to simulate 1-butanol, as well as ethanol, and numerous other ...
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39 views
How to create a Liquid tight cable seal in a fuel storage tank
I am working on a telemetry system where a liquid level sensor (Hydrostatic pressure sensor) is used to monitor the volume of fuel (gasoline / diesel) in an underground storage tank.
The sensor has ...
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Pressure reduction and maintain back-flow from air compressor
I have an air compressor ($P_{max}=4\text{ bar}$) and for my application as an open cycle, I would like to use the $P_{max}=2\text{ bar}$ along with maintaining backflow of the air. Can anyone suggest ...
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1answer
59 views
Designing a Chilled Process Water System for Small Plant
I am designing a new, closed loop,chilled water system for our small injection molding outfit and can use some help where to begin. Here are some of my knowns:
Northeast NJ, USA, no air conditioning. ...
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1answer
65 views
Modelling gas desorption from a still solution (e.g. a beer)
The common way to model or estimate gas (e.g. CO2) desorption rate from a liquid solution is by using an equation similar to this one
$J_{CO_2} = -k_L a(H·C^G_{CO_2} - C^L_{CO_2})$
where $J_{CO_2}$ ...
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32 views
If I replace a flow orifice with a Coriolis flow meter of the same size do I need to worry about pressure drop with the new Coriolis meter?
I have a 3 inch line with a 1.5 inch flow orifice. If I take out the flow orifice and put in a 1.5 inch coriolis meter will the pressure drop be the same or better with the new coriolis meter than ...
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2answers
286 views
Can Fortran 90 be used with Aspen Plus, or only Fortran 77?
I am attempting to write a user model in Fortran that can be connected to the Aspen Plus process simulator. Can Fortran 90 be used, or does Aspen only work with the older Fortran 77? I have checked ...
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64 views
How to find the balance position of valve downstream a tank?
We have a tank which has a constant inflow of water (Qi). The level (h) of water in tank is controlled by opening/ closing (l) a valve downstream of the tank. Overflow height of the tank is 4 meter. I ...
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39 views
How to identify the time delay of manipulated variables which are important to the final quality of polymer product
In a polymer production process, there are a lot of manipulated variables(MV) such as temperature ,pressure , or level of reactor that affect the quality of my polymer product.
However, it usually ...
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79 views
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 ...
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1answer
39 views
Real world applications where one would use a force function in PLC programming?
I'm curious about which scenarios one would use a force function when using a PLC programming interface. Examples pertaining to process engineering, manufacturing, or industrial settings would be ...
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Industrial machinery and equipment [closed]
I am a mechanical engineer who is interested in learning different processes and equipment mainly used in process industry namely, textile, chemical, sugar mill, and other food process industry.
Is ...
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2answers
51 views
Is there any method to recycle air-pollution into fertilizer?
Vehicles and Factories produce air-pollution like Nitrogen Dioxide(NO2) and Sulfur Dioxide(SO2).
Plants use Fertilizer with those same compounds (NO2 & SO2)
So, by what method can air-pollution ...
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282 views
How to use VBA on Aspen Hysys? [closed]
I am trying to write a program on Aspen Hysys. Hysys has a script manager to write scripts using Visual Basics for Applications syntax. Having no background in VBA, I'd like some help to:
Import the ...
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1answer
195 views
How does an industrial engineer develop a process? [closed]
I would like to know what industrial engineers use for planning and developing a process:
What is the most widely business analysis modeling language used (Think ...
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2answers
83 views
Valve first,then heat exchanger OR heat exchanger first then valve
In my exam, I was given 2 options to design a process. Assuming a saturated liquid coming out from the separator, A) should the stream pass through a valve to reduce pressure, then to heat exchanger ...
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1answer
74 views
How do you get a closed vessel to >90,000 psi internal pressure
Im trying to build a cold isostatic press with a internal vessel area of 300mm3.
A cold isostatic press forms green metal components using pressures greater than 90,000 psi.
Using an oil or water/...
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1answer
96 views
Boiling Point, Pressure and Distillation
I have a line in my text that states the following:
"For systems with low boiling points (e.g. Ethane-Ethylene, propane-propylene etc.), high pressures are used so the vapour leaving the column at ...
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1answer
180 views
Chemical Engineering Process Analysis - Process Flow Calculations using linear matrices
I am doing a process flow question and trying to calculate the grams of $\text{C}_{10}\text{H}_{14}$, $\text{C}_4\text{H}_6\text{O}_3$, and $\text{C}_{12}\text{H}_{16}\text{O}$ produced during a ...
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2answers
247 views
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 ...
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1answer
77 views
How do you calculate the required power of a disk turbine (Rushton turbine) to rotate a fluid at a given speed?
I am designing a potato peeler which is practically a bucket that has a rotating disk (figure below) at the bottom driven by a motor. Water and potatoes are put inside the bucket and the disk rotates ...
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2answers
379 views
Can I control latent/sensible heat changes in a counter-flow, induced draft cooling tower using climate?
Some extensive background information to start
I'm attempting to reduce water consumption at 25+ production facilities, and I've identified that the largest consumption of water (60+%) comes from ...
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1answer
127 views
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 ...
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1answer
378 views
What is the gain and time constant of a system with a constant output?
For example, if your transfer function is defined as :
$$\frac{H(s)}{Q(s)} = \frac{1}{5s}$$
What would the gain and time constant be in this case (since it's usually in the form of $\dfrac{k}{Ts+1}$ ...
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39 views
Why have cascading vessels in the 'B' part of the 'AB' wastewater treatment process?
The AB process is wastewater treatment process that works like this:
'A Stage': Wastewater is (after mechanical treatment) subjected to a high load activated sludge process where also a lot of ...
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2answers
2k views
Derivation of Overall Mass Transfer Coefficient
The flux in the gas can be written as:
$$N_{1}=k_{p}(p_{1}-p_{1i})$$
And the flux in the liquid can be written as:
$$N_{1}=k_{x}(x_{1i}-x_{1})$$
And we know that $$x^*_{1}=\frac{p_{1}}{H}$$
How ...
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2answers
108 views
Second Order Transfer Function Question regarding Overshoot Formula
If I have a closed loop second order transfer function such as:
$$\frac{10-s}{0.3s^2+3.1s+(1+24K_{C})}$$
Can I still use this formula for overshoot (when a step input is applied) ?:
$$\frac{A}{B}=e^{...
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1answer
141 views
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 ...
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1answer
134 views
Mass Transfer from an Oxygen Bubble
I think there is an error in this questions solution and I want someone to check:
Example 8.1-4:Mass transfer from an oxygen bubble A bubble of oxygen originally 0.1 cm
in diameter is injected ...
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1answer
525 views
How do temperature and pressure influence the rate of evaporation of water in a closed vessel?
I am trying to solve a fairly simple question but I'm kind of stuck on the technicalities:
Imagine that water is evaporating into initially dry air in the closed
vessel shown schematically in Fig....
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79 views
Purification of wet-process phosphoric acid
I'm doing my senior design class and I have design a chemical plant that produces phosphoric acid by reacting phosphate rock with sulfuric acid. The phosphate rock has a lot of impurities, some of ...
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1answer
181 views
Problem with process controls/simulink?
I have an issue with simulink, basically it's to do with a second order system, well two first order systems in series. As I understand it as you increase the damping factor (above 1), the system ...
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1answer
141 views
How can I process plastic to give the impression of a leather finish?
During the '80s and the '90s, a lot of media cases were made of thermoformed PVC. I believe this trend was created by Disney and Blackbourn with their VHS cases. Then with DVDs, industrial standards ...
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Efficiency model for centrifugal pumps, using relations from Europump's Ecopump project
Context:
I'm trying to create a mathematical model for centrifugal pumps. This model should describes how the operational variables of centrifugal pumps $(Q, \Delta P, ...)$ related to it's design ...
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1answer
416 views
Gas cleaning in activated carbon filters - How much moisture is needed and why?
Biogas and sewage (typically around 60% CH4, rest CO2) gas is typically treated in activated carbon (ac) filters to remove H2S and siloxanes. The ac filters need a small amount of oxygen (>0,4%) to ...
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2answers
395 views
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 ...
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What is the retention time distribution in an STRcascade when the reactors are of uneven side and we have some recircultion?
Consider 2 or 3 stirred tank reactors as a cascade. The sizes are different. A part of the throughput is recirculated from the last to the first. The mean hydraulic retention of course is ...
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1answer
736 views
How to prevent static buildup in an electric burr mill coffee grinder?
Every morning when I get up, I use this coffee grinder to grind beans for my morning coffee.
When I remove and subsequently open the top of the bin, I often find that enough static electricity has ...
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0answers
51 views
SBR-like reactors without decanters?
Sequencing batch reactors let sludge settle before drawing off the supernatant. For this, decanter arms are often used. An example is here.
The challenge is to draw off the supernatant without ...
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0answers
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What procedure do steel plants use to recycle water vapor?
As you may know Steel plants and Tile Factories use a lot of water. I want to know how do these factories recycle water vapor which is mixed with flue gases to reuse it?
Do they take advantage of Heat ...
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0answers
128 views
What are the best materials to use for producing drinking water from the Air?
There are several companies producing equipment that produce drinking water from the air. They use dessicants, hygroscopic brine, or deliquescent salts, to adsorb water from atmospheric humidity. ...
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2answers
4k views
What's the difference between annealing, curing and sintering?
All these processes sound like structural change caused by heating.
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1answer
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Filter Area for given flow rate
Background
For a washing process after a crystallization we want to know how much filter area we would need and if said area will work for our fixed volume flow.
Calculation
$\dot{V_F}$ has a ...
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1answer
582 views
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, ...
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1answer
456 views
What makes a good piping and instrumentation diagram tool?
A while back, I asked this question for a free Piping and Instrumentation Diagram (P&ID) software on softwarerecs.SE. I described the core features of a P&ID software thusly:
Where a proper ...
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5answers
595 views
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 ...
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1answer
162 views
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 ...
