Questions tagged [chemical-engineering]
For questions about processes in commercial chemical manufacturing.
68
questions
-4
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0answers
18 views
I could find the rate of reaction. But am really not able to find the molar mass of the polymer [closed]
Methyl methacrylate was polymerized at a mass concentration of 200 g dm−3 in toluene using
azobisisobutyronitrile as initiator at a mass concentration of 1.64×10−2 g dm−3 and a reaction
temperature of ...
3
votes
0answers
20 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 ...
1
vote
0answers
87 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 ...
0
votes
0answers
15 views
Preventing Precipitation/Undilution: Shall I Try Another Solvent?
Thank you for your time in advance.
Our facility is about $\pu{4000 ft}$ in terms of elevation.
One of the main chemicals we manufacture is RAD140 or $\ce{C20H16ClN5O2}$.
We use DMSO ($\ce{(CH3)2SO}$),...
0
votes
0answers
14 views
Electroplating: What exactly does an additive/ brightener do in the electrolyte?
A carrier or supressor is generally a poly-oxyalkyl compound that is instrumental in suppressing the electrolytic current. This is achieved by the formation of a diffusion layer when the additives ...
4
votes
1answer
82 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 ...
0
votes
1answer
118 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 ...
3
votes
1answer
86 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.)
0
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0answers
19 views
Doubt's regarding inputting surface reaction for Chemkin Pro
I want to simulate the reaction of a mixture of ethanol and Hydrogen Peroxide on $\ce{Pt}$ using Chemkin Pro. I want to create a surface input files which will include surface reaction mechanism of ...
0
votes
0answers
157 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 ...
1
vote
0answers
32 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'...
0
votes
2answers
50 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%....
0
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0answers
12 views
Measurement of Energy Density
I'd like to ask how researchers measure/calculate the energy density for chemical fuels? Do they just measure the enthalpy change of combustion (△H combustion) in a calorimeter and then divide it by ...
-6
votes
1answer
127 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 ...
1
vote
1answer
55 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 ...
3
votes
1answer
141 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
2answers
54 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.
4
votes
3answers
122 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{...
0
votes
1answer
27 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 ...
-1
votes
1answer
29 views
VOC conversion question
I'm trying to find out if a particular paint is considered low VOC. The only piece of data I have available is that the VOC content is $\pu{10 \mu mol / m^3}$. What does that equal in $\pu{g/L}$ of ...
0
votes
0answers
58 views
X-ray bombardment of CaCl2 and its resultant chemical changes
If one were to take $\pu{1 mol}$ of pure liquid Calcium Chloride (at $\pu{600 ^\circ C}$) and bombard it with $\pu{7.65 \times 10^{14} Ci}$ ($\pu{2.83 \times 10^25 particles}$) of x-rays ($\pu{75 keV}$...
1
vote
1answer
206 views
What is the difference between ideal stages and transfer units in a packed bed gas absorber?
I am having a hard time grasping what these two concepts are supposed to mean and how they differ. What I know so far is:
In a counter-current gas absorber, if we set the inlet and outlet ...
asked Oct 28 '19 at 16:24
Pritt says Reinstate Monica
8,0073 gold badges27 silver badges80 bronze badges
1
vote
0answers
51 views
Is it possible to create an arbitrary, stable, unique chemical fingerprint? [closed]
Context: I want to be able to hash real-world objects
Is it possible to create a substance containing a combination of elements (or isotopes?) in a random and difficult to reproduce (but simple to ...
0
votes
1answer
81 views
Is it possible to make micelles to pick up Microplastics from water?
I'd like to know if I could get micelles to pick up microplastics in water. I read that microplastics are sometimes charged, so can we make the lyophobic end to pick up microplastics, so that they can ...
2
votes
0answers
80 views
How to charge titanium dioxide particles for a DIY e-paper capsule? [closed]
I'm trying to make a single e-paper capsule (1 cm × 1 cm) at home. At first, I tried to charge the $\ce{TiO2}$ particles by putting them in $\ce{H2O}$ with $\ce{NaOH}$ and then putting that whole ...
0
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0answers
38 views
Chloride Process TiO2 recovery
In the chloride process (the process used to create titanium oxide from titanium ore), how is TiO2 collected? What prevents the TiO2 from building up on the walls of the reactor chamber?
It's my ...
0
votes
0answers
32 views
Reaction between chlorine gas and oxygen at 600 degrees Centigrade
Chlorine gas will not normally react with oxygen gas directly at STP. However, would the two react at standard pressure and 600 degrees Centigrade?
0
votes
1answer
49 views
Numerical simulation and calculations of pH
a. Reaction of $\ce{CO2}$ addition in water is as follows:
$\ce{CO2}$ + $\ce{H2O}$ $\ce{->}$ $\ce{H2CO3}$
b. Then, pH of $\ce{H2CO3}$ solution is increased to 12 by addition of 1M $\ce{NaOH}$.
...
2
votes
0answers
63 views
Why will A atoms diffuse from β phase to α phase and B atoms from α phase to β phase?
At the initial compositions 1 and 2 of $α$ and $β$ respectively the chemical potentials of A and B atoms in each phase can be found by extrapolation of the tangents to the free energy curves at 1 and ...
2
votes
1answer
210 views
Why do we use Ḡ (“G bar”) as a notation for partial molar free energy?
For partial molar entropy there is a bar that is positioned above the $G$ with a subscript I that is sometimes added to the $G~(\bar{G}).$ The bar I read sometimes denote the "partial nature of the $G$...
2
votes
1answer
373 views
What are glues/adhesives for cardboard boxes/crates made of?
Open cardboard boxes/crates, often for foodstuffs, are often glued to hold their shape. What is the glue/adhesive made of?
I ask to know if it is biodegradable, such that it is suitable for ...
0
votes
2answers
214 views
Does this reaction require catalyst/solvent?
Planning on synthesising 2-formylphenyl benzoate by reacting benzoyl chloride with salicylaldehyde. Since both Benzoyl chloride and salicylaldehyde is liquid, will it require a catalyst/ solvent? Or ...
6
votes
1answer
120 views
How can hydrogen and oxygen coexist in high temperature? Where did the oxygen come from?
A gasification worked with the combustion of bio pallets with production of syn gases. Pure oxygen and $\ce{H2O}$ were fed into the combustion reactor to combust the pallets with no opening of any syn ...
1
vote
0answers
58 views
Correct Generalization for Adair Equation?
I know how to derive the Adair Equation for n binding sites the long way, writing n+1 mini equations and linking them to relate all sub $K_b$ values to $K_{b-intrinsic}$.
Tried to find a general ...
3
votes
2answers
168 views
Can a reactor be operated at both reflux and above atmospheric pressure?
I'm not a chemist by trade so my experience in the lab has probably not been as in-depth as most of you. I've been tasked with investigating a proposed reaction in which an organic mixture (mostly ...
1
vote
0answers
193 views
Impact of pH? Change in Binding Affinity of protein-ligand complex based on pH and Kd?
When the $\mathrm{pH}$ was $5.0$, the temperature was $\pu{25 °C}$,the $K_\mathrm{D}$ was $\pu{5 μM}$, and [L] was equal to $K_D$, the protein(s) were half bound.
Question considers half bound ...
1
vote
1answer
38 views
Chemical Equilibria - Fraction Bound equation based on Kd, [R], [L], [RL], is actually an average?
Let's say 150 stem cells express exactly 150 copies of the same mebrane antigen X. While all differentiated cells express exactly 15 copies of X. To the cell mixture you add a large amount of 0.2 μM ...
2
votes
2answers
65 views
Thermodynamics - Series Reaction - Estimating mols of reactants based on Free Energy of Rxn
Question
Three reactions occur simulteneously (assume ideal) at $\pu{T = 0^\circ C}$.
$$\ce{A<=>B<=>C<=>D}$$
a) With $\Delta_r G^\circ_\text{AB} = \pu{400 J/mol}$, $\...
2
votes
1answer
75 views
Simple alternative to UNIFAC to prove that a mixture containing 1ml of x and 5 litres of propylene glycol is not flammable?
Section 2.6.1 of the REGULATION (EC) No 1272/2008 (CLP) defines a flammable liquid as:
Flammable liquid means a liquid having a flash point of not more than
$60 ^{\circ}$C.
So data on flash ...
3
votes
1answer
98 views
Equation for overall heat transfer coefficient
The heat flow (in $[\pu{J/s}]$) through the wall of a tube of length $L$ and inner radius $R_0$ is
$$Q = (2πR_0L)U(T_{1\infty} - T_{2\infty}),$$
where $T_{1\infty}$ is the bulk temperature in the ...
1
vote
1answer
63 views
What would be a stable way to hold lithium hydride powder?
I currently have 100 grams of lithium hydride powder that needs to be held in a solid form. Initially, I was considering using cement, however, the moisture require converts the lithium hydride to ...
0
votes
2answers
115 views
Flow rate of the fuel consisting of ethanol and water burning in air of a given flow rate
I hope that someone could give me some hints or tips on how to approach this question, even though these types of questions are usually closed off as homework.
A burner is run by a fuel mixture of $\...
1
vote
1answer
197 views
Heat of formation method
For enthalpy calculations why is it that in some cases the "heat of formation method" is used? I know that $ΔH_f$ represents the heat required to form the compound at standard temperature and pressure ...
1
vote
0answers
55 views
Reference conditions for balances on nonreactive processes
In one of the examples in my book (Elementary Priniciples of Chemical Processes) where I am asked to calculate the rate of heat input required to heat a stream of methane and air from 20°C to 300°C, ...
1
vote
1answer
43 views
How do you figure out fuel specific impulse non-experimentally?
Simple question, probably very complicated answer:
Without building a test engine/rocket and finding out experimentally, that is to say, based on chemical characteristics alone, how can one compute ...
2
votes
1answer
26 views
What are standard controllers for automatic pH control?
My background in control theory comes from electrical engineering (robots, motors, etc.) and I want to build a control system for automatic pH control.
Can I directly apply my knowledge from ...
2
votes
1answer
79 views
Double surface in the pressure temperature concentration curve for a binary mixture
In the 3 dimensional diagram given, when a constant pressure plane intersects with the double surface, it produces a looped curve without a maxima or minima. What is the double surface and how is the ...
2
votes
1answer
258 views
Dependence of mass transfer coefficient on solubility
Does solubility of the solute affect the value of the mass transfer coefficient?
The book I am following mentions that the mass transfer coefficient is a characteristic of the constituent and its ...
3
votes
0answers
119 views
Do theoretical plates required to obtain a pure product decrease under vacuum distillation?
For this question I am using Ethanol as an example. The following is the vapor-liquid equilibrium diagram for Ethanol under atmospheric pressures.
Under reduced pressures do the number of theoretical ...
1
vote
0answers
24 views
Can diamond be grown on copper wires using chemical vapor deposition techniques?
I am asking this as a follow-up to another question I asked earlier. It is regarding how to make higher voltage transformers. Diamond is a good dielectric material and would be good for using as a ...
