Questions tagged [chemical-engineering]
For questions about processes in commercial chemical manufacturing.
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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
$$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
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How can the reaction heat be ignored in an energy balance?
I have received from my professor the following (here summarized) problem:
A first-order exothermic reaction A->B takes place in a tubular reactor (typical PFR). The tube is cooled to a constant ...
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Literature recommendation - non-stationary heat transfer in porous solids
I am trying to calculate a non-stationary heat transfer to a porous spheres by conduction.
These spheres are placed in a thin metal tubes with a known heat capacity. Hot/cold air (or similar gaseous ...
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1
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How to relate equilibrium constant and equilibrium conversion?
For the following gas phase reaction:
$$ 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}{\...
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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?
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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 ...
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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 $\...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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1
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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 ...
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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.)
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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 ...
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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'...
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2
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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%....
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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 ...
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1
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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 ...
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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.
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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
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3
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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{...
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1
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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 ...
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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 ...
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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 ($\pu{75 keV}$...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 $\ce{NaOH}$.
...
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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 ...
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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 $G$...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 $\Delta_r G^\circ_\text{AB} = \pu{400 J/mol}$, $\...
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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 ...
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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 ...
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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 ...