Questions tagged [chemical-engineering]

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

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18 views

Estimating rate of drying by comparing identical process with different ambient humidity

We have a drying process where we take a thin bread product and cool it in a room at 11 C and 90% relative humidity. The product comes in at 80 C and comes out at 22 C. There is air blowing across the ...
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21 views

Heat transfer Chemical Engineering [on hold]

could anybody please help me with these two questions, i have been stuck on them for a very long time Many thanks]2
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1answer
48 views

Identify plant transfer function to design PID controller

I am trying to find the transfer function of a plant that contains numerous equipment including a heater, several tanks, pumps, membranes etc. I need to design 2 PID controllers: the first one to ...
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14 views

Where to purchase a high pressure electrochemical cell [closed]

I want to purchase a high pressure cell that's corrosive resistant and can perform impedance spectroscopy tests. Is there any company out there that can make this cell? Specs: volume: 10ml pressure: ...
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8 views

Custom User Models in Aspen Plus

I'm trying to simulate a purifier in Aspen Plus in a cryogenic system. This purifier is just meant to change the pressure of the outlet stream based on the inlet flow and pressure (we are using the ...
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1answer
16 views

Doubt regarding meta-stable and labile region of a supersaturated solution

I have read in a paper that the for formation of new crystals in a solution the energy released due to formation of solid from solution should be more than the energy needed to overcome solid-liquid ...
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10 views

Which version of the Kozeny-Carman equation is valid?

I am learning fluid mechanics, and I've come across the Kozeny-Carman equation for a packed bed in laminar flow conditions as: $$\frac{\Delta P}{L}=\frac{150\bar{v_0}\mu}{\phi^2D_p^2}\frac{(1-\...
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30 views

What type of pump is recommended for pumping gasoline/petrol in vapor phase?

I would really like to know your input, perhaps there are regulations on this that I'm not aware of that can help out regarding the overall safety of the process.
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Aspen cost estimation

I'm currently simulating a plant for biofuels production, part of the job is to estimate the costs associated to the construction of the plant, as well as energy consumption cost, etc. However, I am ...
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17 views

Are there any books which show how to design electrical coil heat exchangers?

I need to design an electrically powered gas heater, but i need to do so in detail. I'm looking for a guide similar to the shell and tube heat exchanger design guide in coulson and richardson's ...
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1answer
14 views

What is the mechanism of adsorption-desorption on biochar obtained from slow pyrolysis/ torrefaction?

Biochar is a major by-product from pyrolysis along with bio-oil and it is considered an important chemical feed-stock because of many light oxygenates. I have read some papers on using bio-char use ...
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31 views

How to calculate flow rate and direction in system with multiple blowers

I have an odour control system where foul air is being extracted from multiple sources and then pushed into a scrubber vessel. Normally, all my designs look something like this: https://ibb.co/...
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1answer
32 views

How to control precisely the wall temperature of a tubular reactor?

I have modelled a multi-tubular reactor performing a Fischer-Tropsch synthesis of alkanes and I was wondering about the stability of such a reactor. Even a very tiny deviation of the wall temperature ...
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35 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 ...
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1answer
26 views

Doubt in proof of condition dG<=0

I tried proving the condition dG<=0 where G is Gibb's free energy and instead ended up proving dB<=0 where B is exergy. Can someone please explain what went wrong with my derivation. I have ...
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1answer
24 views

the volume in hydraulic retention time is of reactor/container or liquid

I have a tiny reactor, and the volume I need is 425ml. If there is no/few other reactants, then the volume in hydraulic retention time is clear: reactor/container's ...
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1answer
36 views

Magnetic treatment of hard water to prevent scale and corrosion? How does this work?

I ran across this company at their booth at a Tradeshow (2018). They claim to have a chemical free (and as far as I can tell - a power free) treatment method for hard water to minimize scale and ...
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2answers
53 views

Systems In “Thermodynamic Equilibrium”

I'm trying to find an answer to a question in one of my thermodynamics textbooks. (Undergraduate chemical engineering is the context). It is a conceptual question, asking, "Do all systems in ...
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3answers
40 views

Flaring System in Industries

Why is Flaring done in industries? Why can't the same gases be used for production of energy (Thermal energy)? Or why can't the excess gas be recycled in the previous stream from which it came?
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1answer
36 views

equivalent deduction of Non-mechanical thermodynamic work

"Work (as in Thermodynamics) is said to be done by a system if sole effect on the surroundings could be the raising of a weight." So, how is non mechanical work like : Chemical work, Magnetization ...
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32 views

performances of a continuous flow reactor

How can we know the evolution of the oulet concentration of a perfectly well-mixed continuous flow reactor taking into account the residence time distribution function called $E(t)$? I have heard ...
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0answers
36 views

Eulerian description of fluid flow

In Eulerian description of fluid flow, we observe how the properties of the fluid are changing at a point. Since a point has zero dimension hence a zero area, how can we make sense of the 'finite ...
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0answers
43 views

Enthalpy vs Heat

If we have a closed cylinder filled with a gas and we heat it, by $1^{st}$ law we have: $\Delta q=\Delta U$ (?) since $\Delta V$ = 0. But $\Delta H= \Delta U+ V. \Delta P$. What does that difference ...
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1answer
22 views

Entrainers to distill MTBE from Methanol? - Chemical Engineering Question

What have you found to be some effective entrainers to distill MTBE from Methanol, given the azeotropic conditions at 67%. I have tried to simulate 1-butanol, as well as ethanol, and numerous other ...
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14 views

calculating amount of oxygen in feed when there is excess oxygen

problem: In the Deacon process for the manufacture of chlorine, hydrochloric acid, $\text{HCl}$, and oxygen, $\text{O}_2$, react to form chlorine, $\text{Cl}_2$, and water, $\text{H}_2\text{O}$. ...
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53 views

Solid-liquid separation of a crystal slurry

Let me preface my question by saying I am a recent chemical engineering graduate and apologize if my inexperience shows. I have designed a batch process which results in a water slurry stream ...
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1answer
28 views

head coefficient and volume coefficient for centrifugal pump

If I need to calculate the head coefficient using $c_h=\dfrac{gH}{N^2D^2}$ and the volume coefficient using $c_q= \dfrac{v}{ND^3}$ while keeping $N$ (impeller rotational speed in rpm), how can I make ...
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1answer
66 views

Boundary conditions in a heat transfer problem

One end of a small insulated rod is attached to a support which is maintained at a constant temperature of 473 K,and once the rod has reached a uniform temperature in its entire length the insulation ...
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39 views

Petroleum/Reservoir Engineering: Estimating Cumulative GOR (Gas Oil Ratio) & Cumulative Oil Production

I have a data set from producing oil/gas wells from multiple (separate) drilling locations. Note that a given well can either be conventional or unconventional. Overall, the data set retains info ...
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16 views

Why can we extend the derivation of delta(S mix) to ideal solution from ideal gas behavior?

The formula for change in enthalpy for ideal gas is derived using ideal-gas law which cannot be extended to ideal solutions (my intuition). Then why can we extend the formula of delta S mix to ideal ...
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1answer
41 views

How to derive phase equillibrium criteria for more than 2 phases mathematically?

I know the derivation of phase equilibrium criteria derivation for 2 phases. I am not getting how to extend the derivation to more than 2 phases. Please help me out on that. Thank you
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10 views

Deriving Enthalpy in terms of (T,V) and (T,P)

We are being asked to develop thermodynamic expressions for the enthalpy of a system in terms of (T,V) and (T,P). I understand that the Legendre Transform can be used to find H=H(S,P), but I'm getting ...
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1answer
36 views

Issues creating a high pressure chamber for corrosive solution

I'm trying to do an experiment on high pressure's effect on the electrical impedance of a really corrosive solution. I'm aiming for at least 2,000 psi with a pressure chamber but the only material I ...
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1answer
52 views

pH calculations for boiler water

For water steam cycle in a "combined cycle power plant" containing 3 boiler drums and dosing of 5% ammonia solution in the condenser. How can I calculate the pH of the boiler water in each of the ...
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1answer
71 views

CSTR properties - What happens to conversion of products if I change the reactor size?

For example, initially this reactor is having a 2nd order reaction of $-ra=kaCa^2$ and it has a fractional conversion of 50% in a CSTR. I replace it with something 1/6 as large. What happens to the ...
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1answer
33 views

Minor loss due to splitting of pipe

I am solving pipe flow problems and it came to my mind how does one find out the minor loss associated with the splitting of pipe. Here how does one find the minor loss associated when the flow is in ...
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0answers
56 views

How can pitot tubes give us local velocity in a flow

I am studying about static pressure,dynamic pressure and the principle behind pitot tube. However in pitot tubes we apply Bernoulli equation between two points which are not on the same streamline. ...
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1answer
60 views

Calculate the specific surface area of a mesoporous sample

I'm a nanoengineering student who's been stuck on the following problem for a few days. I've gone back over my professors slides, watched podcasts from an old professor, etc. etc., but don't ...
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27 views

CSTR exit conditions [closed]

Will there be other factors such that it will affect the exit conditions of the CSTR to change ? For example, the temperature of the reactants that will be lost to the surroundings
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67 views

What are the raw materials for water filter housing production? [closed]

I want produce water filter housing (like below images) who can tell me what are need raw material for these? Best Regards
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1answer
62 views

Contradictory result for mass balance

I solved this problem by doing a mass balance for the mixing chamber and an energy balance for the water heater and the mixing chamber as follows: $\dot{m}_{\text{mix}}=\dot{m}_{\text{Tank}}+\dot{m}_{...
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38 views

Polyurethane with microbial resistance properties

I'm looking for a polyurethane with microbial resistance. Doing some research I found two commercial types: DESMOPAN 9392A and DESMOPAN 2792A. Both are manufactured under GMP conditions and limited ...
3
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1answer
714 views

Can current passing through a wire potentially ignite gasoline? If not, why?

I am doing some restauration on my old Vespa and since the fuel indicator doesn't work, I took the fuel gauge system out of the tank and tried to understand how it works to repair it. Apparently, 3 ...
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2answers
72 views

How can I vaporize metals?

What are some common ways that I can vaporize Metals into a vacuum chamber? How can I keep these Metals in a gaseous state?
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1answer
36 views

Can chemical vapor deposition chambers be used to lay down thick layers of metal?

Can CVD Chambers be used to lay down thick (~1 mm) layers of metal?
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1answer
25 views

How can I convert volume as a function of time to mass or mole as a function of time for a dissolving drug particle?

I have been given a spherical drug particle that dissolves by surface erosion into the bloodstream. The rate of dissolution is proportional to the exposed surface area of the particle. I have to model ...
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1answer
257 views

Entropy change in a throttling process

In an adiabatic throttling process of ideal gas: I understand that mathematically lost work is given by Tsurr * entropy generated. But intuitively I can't understand if there is not heat exchange ...
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1answer
66 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 $J_{CO_2}$ ...
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2answers
51 views

what classes should I take so that I can perform research into finding catalysts to split water into oxygen and hydrogen? [closed]

I am a freshman student and I am very interested in using solar energy to break water into hydrogen and oxygen. So, I want to know which areas are important in this regard..
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1answer
27 views

How To Find Reheat Parameters In an ideal rankine system

So I was trying To Solve a problem on reheat Rankine cycle . I can Solve for everything Aside The part of The Reheat That has Entropy constant With the Main boiler entropy.. I don't know if when ...