Questions tagged [chemical-engineering]

Use this tag for questions within the problem domain of chemical engineering.

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Distillation modelling McCable Thiele, Chemical Engineering

I am using an extractive distillation column to seperate ethanol and ethylene glycol. I am trying to find Rmin however its proving difficult as the the top operating line, q-line and bottom operating ...
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15 views

What is the energy and capital cost of NH3 from Haber Bosch plant that takes in pure H2 and N2?

A question that becomes particularly relevant for "the hydrogen economy" or in the event that IGCC coal baseload electric generation seeks off-peak markets for hydrogen. I can't seem to ...
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23 views

Calculating estimated Overall Heat Transfer Coefficient

I have problem where I'm trying to determine the Overall Heat Transfer coefficient of a heat exchanger that uses the latent heat of vaporization of water in the process. I know the Q value I'm trying ...
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15 views

Determining length of interstage cooling coils for removal of heat

I'm currently trying to determine the length of cooling tube required to remove a specific amount of heat from my exothermic reactor in stages. I'm aware I need to use the equation $Q = UA \theta_{...
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1answer
30 views

How can I calculate the density of air?

I major in chemical engineering, and I'm solving a example of unit operations. The textbook is Warren L. McCabe, Unit Operations of Chemical Engineering 7th ed. Here is example 24.1. And this is its ...
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1answer
41 views

How to compute velocity distribution in the developing boundary layer on the cylinder

Air flows perpendicular to the axis of a cylinder $a=1$ cm in diameter. Air speed upstream of the cylinder is $U=6.72$ mm/s and its kinematic viscosity is $2.1×10^{-5}$ at 350 K. I want to obtain the ...
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1answer
88 views

Is it possible to use direct air capture technology for CO2 on a non-commercial level?

CO2 is used as fertilizer in aquariums where it's brought into the water with diffusors from compressed form in cylinders. Direct Air Capture machines for CO2 have been presented for experimental geo-...
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25 views

P&ID questions on reports, connection, etc

Good day to all of you. I got some questions in my mind regarding on P&ID: In electrical, symbol will have their own default reference name for example "Motor" will use "M" , ...
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1answer
48 views

How to calculate a gas burner dimensions?

I am trying to calculate the dimesnions of a natural gas burner for a hospital. The burner will be heating water. I have calculated the thermal duty that needs to be produced and the water mass flow, ...
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40 views

Navier-Stokes with non-newtonian fluids

So I've got a problem here in fluids. It's driving me insane but I know I'm missing something simple. Up until now we've worked with Newtonian fluids resulting in the "normal" NS equations ...
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1answer
46 views

Recommended books for process engineering? [closed]

I made a career change from machine design to CNG processing. What I’m looking for are some good books/handbooks that cover the following topics. Something similar to Machinery’s Handbook. Piping, ...
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1answer
63 views

Theoretical maximum pressure from combusting LPG

I am curious how to find or estimate the theoretical maximum pressure that the combustion of a LP gas, such as propane, can produce inside of a constant volume, such as in a cylinder. I know what the ...
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1answer
33 views

Is molecular dynamics relevant for an undergraduate Mechanical Engineering degree? [closed]

I am completing my final year undergraduate study in Mechanical Engineering. I've had to have a scope change because my last project was not going to work with the pandemic. I've been given a project ...
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1answer
41 views

Gaps in derivation of thermodynamic property equations

If $h=h(T, P)$. Does $ dh = c_pdT + \left[v - T\left(\frac{\partial v}{\partial T}\right)_P \right]dP \Rightarrow h_2 - h_1 = \int_{T_1}^{T_2} c_pdT + \int_{P_1}^{P_2}\left[v - T\left(\frac{\partial v}...
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1answer
30 views

Determine in and out momentum in shell momentum balance [closed]

How to decide what is in momentum and what is out momentum in using shell momentum balance? My main motive is to understand why at 25:26 in the balance equation at https://www.youtube.com/watch?v=...
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1answer
221 views

Throttle vs Choke vs Damper vs Valve?

Throttles, chokes, dampers, and valves all restrict fluid flow. Aside from specific terminology/usage in internal combustion engines, are these really interchangeable terms, or do they have some ...
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1answer
44 views

Crossflow HX tube and fin, derive Tout hot side as a function of mdot hot side in

Apparatus: Crossflow Tube and fin HX. (liquid-to-air Intercooler), Hot Side: Tube side, gas flowing internally Cold Side: fin side, water flowing in crossflow Goal: Generate an environment in "...
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1answer
55 views

Ash size particle dependency of initial coal particle size in fluidized bed combustors

I'm looking for information on coal ash size in fluidized beds. How dependent is it on the initial coal particle size? Would I expect ash from 5mm coal particles to be significantly larger than ash ...
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1answer
38 views

Can I calculate the amount (mol or mass) of water in a gas, in a heat exchanger, if I know the partial pressure of the water?

Is it possible to calculate the amount of water (mol, mass...) in a gas, in a heat exchanger, if I know the partial pressure of the water? The stream through the tubes is mainly benzene and ...
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1answer
54 views

sinking speed of particle in water

For a Newtonian fluid the sinking final speed of a metal particle is given by this equation : while g is Gravitational acceleration , $\rho_P$ = is particle density , $\rho_F $ = is fluid density ,...
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1answer
54 views

How do I calculate the density of a lined pipe?

I'm having some trouble figuring out how to calculate the density of a lined pipe given the diameter measurements and the specific gravity of the materials. The Problem Calculate the density of an ...
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1answer
75 views

Help with Mass Flow Rate

I'm a beginner in chemical engineering so apologies in advance if this question is very basic! The Problem You are required to measure the mass and volumetric flow rate of a slurry stream. The slurry ...
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1answer
45 views

Advantages of hydrogen gas turbine over fuel cell

In the setting of large-scale electricity generation, I was wondering why one would want to burn hydrogen in a gas turbine instead of using it to power a fuel cell. Aren't fuel cells more efficient ...
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1answer
519 views

How to calculate kinetic energy of gas flow in pipe given tempearture, pressure, pipe diameter and velocity

Ive been given a question and asked to calculate the kinetic energy of a gas given the temperature, pressure, diameter of pipe and velocity. I've been looking and have been unable to find any ...
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1answer
50 views

Need help with an essay question related to chemical engineering (High School)

I have to do an essay question related to an area of my choice (Chemical Engineering). Could anyone suggest an area of research that is accessible to a High Schooler within ChemEng? Thank You
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1answer
719 views

Safe temperature thresholds for #2 HDPE and #5 PP plastic

It would be convenient to use a temperature adjustable heat plate (element)/mug warmer for the massive amount of blender bottles accumulated over the years. What are safe thresholds to safely warm the ...
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16 views

Macro to atomic scale software

Is there a software that exists that takes a macro object for example a MacBook casing and its composition (Aluminum) and allow you to zoom between the macro scale (a fully rendered MacBook) and the ...
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3answers
82 views

How do you determine how many pumps you need in a pipeline?

I am working on a pipeline design scenario and I am trying to determine how many pumps I need. In addition to this diagram, I'm given a flow rate range and an acceptable velocity to also determine the ...
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1answer
40 views

How can the air pressures exiting from a blower be adjusted?

During this covid-19, I was thinking about designing a low cost simple ventilator using a blower. There is a limit of the inspiratory and expiratory pressures, the inspiratory pressure being higher. ...
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0answers
11 views

How is EPD different / related to anodising?

What is the process of applying dye to anodized surfaces (specifically aluminum)? Is electrophoretic deposition (EPD) just the process used to apply the dye to anodised surfaces? Or is it a ...
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0answers
35 views

Considerations for switching from Conc. Sulphuric acid to Oleum

First off - this project is still in the early planning stages. The basic scope is that a plant want's to switch from using conc. sulphuric acid (~98%) in its process (nitration) to oleum. I ...
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48 views

Why do some pipelines have regular 90 degree deviations? [duplicate]

On this satellite image, there are pipelines extending from a terminal at sea to an LNG (Liquid Natural Gas) storage facility. Why do the pipelines, at regular intervals, deviated from a straight ...
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2answers
68 views

Chemical engineering equivalancy to the spring-mass-damper/RLC circuit

I understand the equivalency between the MSD and RLC circuits. Mass ~ resistance, spring ~ inductor, damper ~ capacitor. With the equations of the form MSD: $$ m\ddot{x} + c\dot{x}+ kx = F $$ ...
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24 views

Slow integration of system ODE under specific conditions in adsorption problem

I am trying to solve the system of ODEs below. I am applying the finite differences to z, so I get a system of ODE that I can solve with a solver like ode45. The problem is that under the conditions ...
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1answer
62 views

What kind of magnetic water conditioner can industrial sinter plant use?

As you can see in the below shematic, the magnetic water conditioners can be used for the pipes of incoming process water on sinter plants to reduce surface tension of water and get fuel consumption ...
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1answer
44 views

Thrust by turbo fan jet engine

How much thrust can I produce with a turbofan jet engine without injection of fuel and with just compression of air, which will be heated by convection if initial temperature of air of 20 oC and its ...
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2answers
188 views

Increasing Kd in PID control loop

Why does increasing derivative gain $K_d$ in a PID controller loop lead to a reduction in overshoot and an increase in rise time? This is not a homework question, it is a question to improve my ...
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2answers
40 views

Difference between light and heavy cracking of hydrocarbons?

Cracked gases usually are quenched after cracking reactions. Why for lighter gases like ethane, indirect quenching is used, But for cracking of heavier naphtha or gas oil, most cooling is ...
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3answers
352 views

P&ID Symbol identification, unknown meaning

I'm aware that answers may vary and it really does depend on the company/country where the PID was drawn but I have checked back for the last 30 years and found no drawing legend that describes what ...
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103 views

How to increase blast furnace top gas temperature?

Why does blast furnace (in Iron & Steel works) top gas temperature stays low and what are the fixes for that to increase without using a burner? The top gas temperature goes below 80 degrees (...
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0answers
24 views

How to furnace-melt bismuth oxide into optical glass?

I have been experimenting with a furnace at my house and am looking to attempt the more difficult process of creating bismuth-oxide based optical glass for the purposes of creating optical elements (...
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2answers
46 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’...
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1answer
138 views

How to calculate initial concentration of first-order reaction in CSTR?

(This question comes from a Chemical Engineering background, but basic Math and Programming knowledge is also required. I hope it still falls in the scope of engineering.stackexchange.com If not, ...
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33 views

Calculate gas velocity from separator

What would be the best way to calculate velocity of gas from a three phase separator? I know that operating temperature is 75F, pressure 1000 psia, pipe diameter 20 inch, and pipe length to the point ...
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1answer
204 views

Calculating Entropy from Gibbs Free Energy?

I guess Cp = dH/dT= dq/dT=dS Thus SdT = integral of CpdT. From that ∆H is given and we can calculate ∆G. However, entropy for this reaction should be -7.4J/molK and I am getting like 26J/molK. Also S ...
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1answer
82 views

Do pressurised cans still pose a risk to bursting in normal conditions, but after being exposed to heat?

We're planning on shipping some items from the US to Australia as you cannot get them here, that being: https://www.chewy.com/sentry-stop-that-noise-pheromone-dog/dp/56486 I have been in contact ...
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31 views

Interface level between 2 components in Liquid-Liquid Extraction, What does it mean?

In LLE physical processes, there is this level (interface) between the 2 components (for example) that is being separated as shown in the picture. I know that the height of this level from the ...
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1answer
90 views

Buying Liquid Oxygen in Small Quantities [closed]

I am trying to work out costs and order parts for a small liquid fuelled rocket I have designed. My oxidiser is liquid oxygen but I can’t seem to find anywhere to purchase it on the internet. Does ...
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1answer
159 views

Sieve trays used in Liquid liquid extraction tower instead of bubble cap and valve trays?

In an LLE operation pilot plant, i saw that sieve trays are used instead of bubble cap and valve trays... In LLE operation, they require good mixing, so i was shocked why bubble cap and valve trays ...
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1answer
662 views

On partial reboiler and total condenser in distillation column

Why is it that a total condenser and partial reboiler are used in a distillation column and it is not the other way around?

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