Questions tagged [process-engineering]

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

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20
votes
1answer
446 views

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 ...
17
votes
1answer
730 views

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 ...
11
votes
1answer
153 views

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 ...
10
votes
1answer
190 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 ...
10
votes
1answer
633 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, ...
10
votes
2answers
505 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 ...
9
votes
5answers
724 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 ...
7
votes
2answers
251 views

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 ...
7
votes
2answers
164 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 ...
6
votes
2answers
2k views

Block diagram vs flow chart?

I was studying a book of control system where i read that a block diagram is a specialized high level type of flow chart So what will be the difference between a normal flow chart and a block diagram?...
6
votes
2answers
85 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 ...
5
votes
2answers
286 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 ...
5
votes
1answer
436 views

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 ...
5
votes
1answer
145 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 ...
4
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2answers
5k views

What's the difference between annealing, curing and sintering?

All these processes sound like structural change caused by heating.
4
votes
1answer
55 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 ...
4
votes
1answer
107 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 $J_{CO_2}$ ...
4
votes
2answers
447 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 ...
4
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0answers
88 views

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 ...
3
votes
1answer
637 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....
3
votes
1answer
1k 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 ...
3
votes
1answer
473 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 ...
3
votes
1answer
66 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. ...
3
votes
1answer
200 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 ...
3
votes
1answer
2k views

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 ...
3
votes
1answer
483 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 ...
3
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0answers
83 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 ...
3
votes
0answers
54 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 ...
2
votes
1answer
192 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 ...
2
votes
1answer
158 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 ...
2
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0answers
13 views

What's the best type of steam Trap for Superheated Steam?

Process Engineering Newbie here. What kind of Steam Traps are best suited for condensate removal in super-heated steam line or manifold? The super-heated steam is to be supplied to a process reactor ...
2
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0answers
77 views

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 ...
2
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0answers
131 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. ...
1
vote
2answers
41 views

How to add a controlled amount of a nutrient solution to a water line

I have an existing water supply system for the cattle on my farm whereby 6 troughs located in different fields are all fed from a common header line. The pressure in that line ranges from 3-5 bar (It’...
1
vote
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 ...
1
vote
2answers
42 views

Choosing Pressure Vessel head

Can I use a conical head at the bottom for a small diameter steam manifold ( Schedule 40- 3 inch dia. and 2 inch dia. ) that needs to operate at high temperature (~450 deg Celcius) and High design ...
1
vote
1answer
102 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 ...
1
vote
1answer
83 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 ...
1
vote
2answers
646 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 ...
1
vote
2answers
53 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 ...
1
vote
0answers
24 views

Reading a value off a screen with a camera

I'm looking to log some information on a piece of equipment I have running at home. It displays the information I want - operating rpm and some other settings - on seven-segment displays. In an ideal ...
1
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0answers
16 views

Custom Models in Process Engineering

I'm using Aspen Custom Modeler to create a model to be used in Aspen Plus and Aspen Plus Dynamics, and I'm having trouble figuring out how to code the mass balance, energy balance, etc. I'm ...
1
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0answers
46 views

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 ...
1
vote
1answer
47 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 ...
1
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0answers
42 views

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 ...
1
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0answers
407 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 ...
1
vote
0answers
43 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 ...
1
vote
2answers
141 views

Second Order Transfer Function Question regarding Overshoot Formula

If I have a closed loop second order transfer function such as: $$T(s) = \frac{10-s}{0.3s^2+3.1s+(1+24K_{c})}$$ Can I still use this formula for overshoot (when a step input is applied) ?: $$\frac{A}...
1
vote
0answers
102 views

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 ...
0
votes
2answers
169 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 ...