Questions tagged [chemical-engineering]
For questions about processes in commercial chemical manufacturing.
99
questions
0
votes
0
answers
34
views
Specific temperature ranges of kinetic combustion mechanisms
Do kinetic combustion mechanisms typically operate within specific temperature ranges? I tested some mechanisms from the scientific literature, and apparently they were only working at temperatures ...
3
votes
1
answer
64
views
Calculating Fractional Yield as a function of temperature for a parallel reaction in a plug flow model
(This question comes from a Chemical Engineering background, I hope it still falls in the scope of engineering.stackexchange.com If not, please move.)
I am trying to calculate and plot fractional ...
- 31
0
votes
1
answer
67
views
Closed pressurized water vessel
Suppose we have a closed container not isolated from the external environment so that heat exchanges can occur on the lateral wall (mainly for convection). The water inside is pressurized by a gas (...
- 23
3
votes
0
answers
35
views
How do polyurethane varnishes cure after only the solvent evaporates
How do polyurethane varnishes cure after only the solvent evaporates?
I believe that polyurethane varnishes have as components isocyanates & polyols that react to form the polyurethane portion of ...
- 149
0
votes
1
answer
85
views
Silver Nitrate Test for Acetylene gas qualification; looking for an appropriate instruction
Phosphine and Hydrogen sulfide along with some other hazardous gases are of impurities of acetylene plants witch are based on the reaction between water and calcium carbide. One of the simple and fast ...
- 115
-4
votes
1
answer
134
views
how I can separate nickel and chrome in single [closed]
How I can separate chrome and nickel from a nickel sulphate,nickel chloride and chrome salt separately??when these mixed up in a single solution.Please tell me how to do it using simple house hold ...
4
votes
1
answer
117
views
Chemical species equations in a kinetic mechanism of combustion
In combustion, for a kinetic mechanism involving $m$ reactions and $n$ chemical species, of the form
\begin{align}
\begin{cases}
\nu_{11}' \mathcal{S}_1 + \nu_{12}' \mathcal{S}_2 + \dots + ...
1
vote
1
answer
72
views
Effectivness factor for a cylinder
I would like to demonstrate the effectiveness factor of a porous cylinder, for diffusion-reaction (only radial diffusion, 1st order reaction, isothermal, diffusion coeff. is constant, steady-state), ...
- 13
0
votes
0
answers
62
views
Heat transfer calculation in open tank equalization
Thanks for your replies guys, sorry for unclear and undefined question. Let me try to reparaphrase my question.
Updated info:
This is the way i try to solve this problem.
I calculate the pipe length ...
- 11
0
votes
1
answer
110
views
Process of Arecoline Extraction
What would be the proper procedure to extract and isolate arecoline, an alkaloid ester, from the seed of the Areca nut, and is it possible to mass produce arecoline using that method?
2
votes
1
answer
431
views
What is the difference between differential yield and selectivity?
I have a hard time understanding the difference between the differential yield and overall selectivity of a reaction.
Levenspiel, Chemical Reaction Engineering writes:
For convenience in evaluating
...
- 29
0
votes
2
answers
129
views
Solvay process and its relationship with sodium chloride and calcium carbonate
I’m studying some chemical engineering process and my teacher made a question in class that nobody knew how to answer it and then she asked to made a search after class. However, I don’t even found ...
- 11
0
votes
0
answers
30
views
Multi compartmental ODE's in chemical engineering
I am alien to the field of chemical engineering. And I am confused about equations, written by chemical engineers, including several variables belonging to different compartments.
Assume that,
$[X]$ ...
- 1
5
votes
2
answers
1k
views
Suitable solvents to dissolve Aluminum Chloride (anhydrous) without generating Hydrochloric Acid (aqueous or gas)
Hypothetically, I have a chemical tank that was brought out of service and the solid deposits at the bottom of the tank primarily contain aluminum chloride. The whole system never sees water, and the ...
- 51
-1
votes
2
answers
503
views
How long can dimethyl sulfoxide be safely stored in a HDPE "barrier bottle"?
How long can dimethyl sulfoxide be contained in a HDPE barrier bottle without any reaction between the plastic and the solvent? I have read that DMSO is not reactive with HDPE, but I would like to ...
- 99
1
vote
0
answers
232
views
Calculating pourbaix diagram of Fe-H2O system at different temperatures
I have been trying to calculate the pourbaix diagram for Fe-H2O at different temperature for my high school research but I am facing a lot of problems. I have several question regarding the ...
1
vote
1
answer
98
views
What chemical reactions takes place in purifying acetylene?
Acetylene produced by water on calcium carbide method contain several impurity compound, that are harmful for welding or other purposes of acetylene and needs to be absorbed from the gas mixture ...
- 115
1
vote
1
answer
287
views
What scientific and technical challenges prohibit the industrial use of the Sabatier reaction?
It seems that the Sabatier reaction solves the biggest problem of climate change — it does create clean gas and hydrogen fuel from the captured carbon dioxide and water (from melting ice).
$$\ce{CO2 + ...
- 119
1
vote
0
answers
81
views
how to make a PEM (proton exchange membrane) out of Nafion Dispersions?
I would like to use a Nafion membrane for a fuel cell project, but the Nafion sheets are hard to integrate. Therefore, I would like a gel type of Nafion that can take the shape of the container I put ...
- 23
1
vote
2
answers
1k
views
Evaporation Rate of Hydrochloric acid
I'm currently working in a Chemical Plant as an intern, and I was given a task to improve the efficiency of the blower, which is already in place right now, by designing a new blower for the ...
2
votes
4
answers
872
views
What non-toxic non-corrosive liquids are used for heat transfer?
I have a steel vessel placed concentrically within a larger steel vessel, resulting in air-filled annulus (air gap) between the two vessel walls (figure below). Due to the existing vessel construction,...
- 187
4
votes
0
answers
64
views
Rate of polymerization for copolymers with two monomers
I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r_\mathrm{p}$ is
$$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
- 91
3
votes
1
answer
153
views
How can the reaction heat be ignored in an energy balance?
I have received from my professor the following (summarized) problem:
A first-order exothermic reaction $\ce{A->B}$ took place in a typical tubular plug flow reactor (PFR). The tube was cooled to a ...
- 31
0
votes
0
answers
24
views
Literature recommendation - non-stationary heat transfer in porous solids
I am trying to calculate a non-stationary heat transfer to a porous spheres by conduction.
These spheres are placed in a thin metal tubes with a known heat capacity. Hot/cold air (or similar gaseous ...
- 133
0
votes
1
answer
899
views
How to relate equilibrium constant and equilibrium conversion?
For the following gas phase reaction:
$$ A\leftrightarrow B $$
The concentration equilibrium constant ($K_c$) can be expressed as:
$$ K_c = \frac{c_B}{c_A} = \frac{\frac{F_B}{\vartheta}}{\frac{F_A}{\...
- 17
-2
votes
1
answer
104
views
Non-RSPO MB glycerin vs RSPO-MB glycerin
Does non-RSPO-MB glycerin function differently than RSPO-MB glycerin? For example in a cosmetic serum /lotion?
- 1
1
vote
0
answers
59
views
Recycling flow if the chemical process of acetylene and hydrocyanic acid
I'm having some issues trying to solve this problem, because the concentration of inert in the recycling flow that I calculated is bigger that the concentration of the inert that is enterying to the ...
0
votes
0
answers
48
views
Which reaction is happening in the preparation of sulfuric acid through contact process?
I've read that in the preparation of $\ce{H2SO4}$ through the Contact process, on the absortion tower, the gas $\ce{SO3}$ is getting in contact with $\ce{H2SO4} (l)$ , because adding $\ce{SO3}$ to $\...
0
votes
0
answers
128
views
Vapor - Liquid Equilibrium (VLE)
Most fundamental equation for VLE is $$ \mu_i^L = \mu_i^V $$
It states that for every component chemical potential must be equal in both liquid and vapor phase at equilibrium. However, in my thermo ...
- 857
0
votes
1
answer
566
views
Is stoichiometric imbalance in polymerization important if the process has an evaporation step?
Polymerization texts stress the importance of stoichiometric balance of the monomers. For example here:
https://www.e-education.psu.edu/matse202/node/606
I can understand how stoichiometric imbalance ...
- 103
1
vote
0
answers
188
views
Ideal CSTR mixing assumption
Sorry if this seems like a silly question but it has me confused a lot. So I have just started taking Chemical Reaction Engineering, and was studying about continuous-stirred tank reactor (CSTR).
So ...
- 47
3
votes
0
answers
415
views
Why do we want to operate at dew point or bubble point when doing flash calculations?
I'm trying to dimension a flash drum for a separation between water and isobutane. I now the total inlet flow (F), the composition of the inlet flow ($z_1$ for isobutane and $z_2$ for water) and the ...
- 121
2
votes
0
answers
58
views
Process parameters of typical chemical processes [closed]
I am researching to opportunity of heat recuperation in the chemical industry be means of high temperature heat pumps. However, I am having some trouble with finding suitable applications. I would ...
- 29
0
votes
0
answers
75
views
How much energy is required to liquify oxygen?
Does anyone know where I can find some documentation of a real-world liquification process, and the energy costs?
I can calculate the heat that must be removed from O2 gas to get to liquid, but how ...
- 337
3
votes
1
answer
333
views
Make pyridine from furfural
Furfural $(\ce{C5H4O2})$ has been used as a feedstock for synthesis. Furfurylamine $(\ce{C5H7NO})$ is made from furfural.
Given that industrial manufacturing ammonia is matured, how about combining ...
- 232
4
votes
0
answers
163
views
How much energy is required to operate a Sabatier reactor?
I am trying to model some industrial processes and having a hard time finding information about the Sabatier reaction. The Sabatier reaction combines $\ce{CO2}$ (and possibly $\ce{CO}$) with $\ce{H2}$ ...
- 337
3
votes
0
answers
226
views
Calculating temperature of partial condenser, flash calculations
The iterative method I have learned to make flash calculations for a binary system where I know the inlet feed (F [mol/s]), total composition of the two components ($z_1$ and $z_2$), the amount of the ...
- 121
2
votes
0
answers
185
views
The Use of AI and Machine Learning in Organic Chemistry
I am trying to do a bit of research into the current use of machine learning in chemical industry. I've been told my original question was too general so I'll try to be more specific about what I'm ...
- 215
4
votes
1
answer
103
views
Modelling pH as function of time and position
I already posted this on the Engineering Stack Exchange under Chemical Engineering as I don't know where it's a better fit.
I have a system whose initial state consists of three different sections ...
- 67
0
votes
1
answer
178
views
Using the right equipment for successful detection of Novichok [closed]
Apparently, Navalny’s biomaterials were flown to Moscow's Nii Sklif lab which didn't find any traces of the poison. But they used an American Agilent Technologies GC-MS [1], while Bundeswehr ...
- 117
3
votes
1
answer
1k
views
How or Why does diesel/kerosene have a much higher 'flash point' but lower auto/self-ignition point than gasoline/petrol?
This is a very common question, but I have yet to find a good theoretical answer to both questions (diesel has higher flash point BUT lower spontaneous ignition temp.)
- 1,793
0
votes
0
answers
1k
views
Thermodynamic and Transport properties input files for Chemkin
I am using Chemkin pro 2009 version. I want to model a decomposition+combustion reaction on my catalyst in a plug flow reactor.So I'll need to create my own Thermodynamic and Transport Properties file ...
- 39
1
vote
0
answers
55
views
Definition of throughput
I wonder what's the exact meaning of throughput in chemistry synthesis, eg. in organic synthesis or production of pharmaceutical products. For instance, what are their units? How are they measured?
I'...
- 64
1
vote
2
answers
77
views
Why am I getting higher conversion values of isopropanol dehydration over a zeolite catalyst than n-propanol dehydration?
The two process are run separetly but under the same condition, same activation of the catalyst, same reaction temperature, same flow.
The initial conversion of n-propanol is ~50% and isopropanol ~70%....
- 411
-4
votes
1
answer
399
views
molecular orbital theory explaining molecular orbitals [closed]
i am a high school student,,and i am confused in molecular orbital theory,,,my confusion is that how bonding and non bonding orbitals are formed at the same time my teacher taught me that the two wave ...
- 29
1
vote
1
answer
151
views
Studying chemical engineering [closed]
My question is pretty simple. Does studying chemical engineering require memorizing manufacturing processes and other complex chemical mechanisms, or does it rely more on the practical side of things ...
- 41
3
votes
1
answer
2k
views
Is silicon dioxide decomposition possible?
I was thinking about this, I made Gibbs free energy calculations and I can't figure out if
$$\ce{SiO2(s) -> Si(s) + O2(g)}$$
is actually possible, even at a ridiculous high temperature.
-3
votes
2
answers
87
views
From diagram, assuming that the reaction is 40% complete in the vessel: a. The weight of the methanol added per day b. The amount of Hl recycled
Here is my solution on the problem and the diagram below is the actual given of the problem. I hope you could help me correct it.
5
votes
3
answers
228
views
Recycle unreacted ethene
The question is this:
You want to make oxirane from ethene and oxygen gas:
$$\ce{2 C2H4 + O2 -> 2 C2H4O}$$
The flow into the reactor is constant at $\pu{200kmol/h}$ of $\ce{C2H4}$ and $\pu{...
- 51
0
votes
1
answer
69
views
Using the electrical potential created by the electron transport chain to power electrical systems
My friend and I were discussing the extremely low energy density of modern batteries and read that food has a much higher energy density. Thus, we were considering the possibility of using biological ...
- 19