Questions tagged [chemical-engineering]

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

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Fluid dynamics of non interacting tanks in series

I have a system like this: and I have to estimate the height of the lower tank. First of all, I'm considering that I have a non-viscous, incompressible fluid in steady flow. Base apertures The ...
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Parameter effects on kinetics of esterification for bio-diesel production

I want to discuss the effect of parameters on the kinetics of esterification for bio-diesel production. In esterification process, temperature effect and molar ration are two important parameters. ...
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Purification of wet-process phosphoric acid

I'm doing my senior design class and I have design a chemical plant that produces phosphoric acid by reacting phosphate rock with sulfuric acid. The phosphate rock has a lot of impurities, some of ...
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What is the longest self support length a chain one molecule wide can be?

Self-support length is the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top this is an important ...
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Dealing with condensation procedures in porous membranes

I came across this publication: Do, H. D., & Do, D. D. (2001). A new diffusion and flow theory for activated carbon from low pressure to capillary condensation range. Chemical Engineering Journal,...
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Question regarding evaluating 1D heat transfer PDE

My question regards cooling of an object using 1D-heat transfer with fixed surface temperatures. First I need to find the solution to this PDE: Based on the conditions, I worked out that the ...
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Book recommendation for hydrodynamics of bubbles, drops, and particles

I am wondering if someone could please recommend to me some references on the topic of hydrodynamics of bubbles, drops, and particles, preferably in the context of complex and bio fluids. I am ...
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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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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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1 answer
239 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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How to apply the permeability value found from an experiment?

I have done a permeability experiment on LDPE in the presence of air using a 25mm circular specimen. At 30'C, the permeability was found to be 1.846 barrer. Now I am trying to apply this permeability ...
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What is the retention time distribution in an STRcascade when the reactors are of uneven side and we have some recircultion?

Consider 2 or 3 stirred tank reactors as a cascade. The sizes are different. A part of the throughput is recirculated from the last to the first. The mean hydraulic retention of course is ...
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What are the best materials to use for producing drinking water from the Air?

There are several companies producing equipment that produce drinking water from the air. They use dessicants, hygroscopic brine, or deliquescent salts, to adsorb water from atmospheric humidity. ...
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Reactor tube material at moderately high temps (600-1000 C) with water vapor as primary constituent of flow

I work with a type of spectrometer (made by Picarro) that uses near-infrared lasers to measure the stable isotopic composition of water vapor. The samples measured are typically liquid water samples ...
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Fastest possible mean (peak?) piston speed on a Diesel engine

On a Diesel engine running distillate fuel (the kind you run in cars, SUV's, trucks, trains, boats, and smaller ships), what are the theoretical and practical limits to maximum mean piston speed you ...
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Heat Transfer in a tubular reactor with constant jacket temperature - impossible solution?

I have received from my professor the following problem: A first-order exothermic reaction A -> B takes place in a tubular reactor (typical PFR). The tube is cooled to a constant wall temperature $...
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Help with friction factors for non-newtonian fluids

I've been researching about friction factors for non-newtonian fluids and I've found quite inconsistent results. The power-law model correlations I've tested do not agree (within some interval) as to ...
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Can the Whitaker Nusselt number correlation be used for a hot sphere in convection with cool air?

The Whitaker Nusselt number correlation (equation 4 here if you don't know it) seems to not be applicable for when the viscosity of the fluid gets higher away from the surface, but it seems to get ...
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Method of separating oxygen from a mixture of oxygen + carbon monoxide

I have a 99,9% oxygen, with 0,1% is CO. Is it possible to separate the CO from oxygen in this mixture? The closer the percentage to 0 for CO, the better. I've read about separation of oxygen from air, ...
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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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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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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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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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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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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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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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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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Can we engineer detergent micelles to pick up Microplastics?

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 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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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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113 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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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 ...
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1 vote
1 answer
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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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How widely used are ethylene receptor inhibitors in fruit packaging & shipping?

Ethylene works as a gaseous "aging" hormone for many fruits. There are lots of papers on ethylene receptor inhibitors (e.g. 1-MCP) to delay this process. I also found out that 1-MCP has been EPA-...
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Distribution of turbulent energy dissipation in a stirred tank

Is detailed experimental information on the distribution of energy dissipation in a stirred tank(45o Pitch blade) available? I require this variation in all directions in a standard stirred tank ...
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Adsorption - what models are used for dry scrubbing?

For scrubbing with activated carbon, air is generally brought through a dry adsorption media, where the contaminant is adsorbed onto the media. I would like to know what mathematical model is used ...
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Eletrolysis of water

The electrolyser used in the process at 25°C and 10.0 bar exhibits a global yield of 82% with a potential of 1.481 V. Determine the electrical energy that can be electrolyzed by year in order to get ...
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Chemical Engineering Question using Raoult's Law

A liquid mixture containing 35.0 mole% acetone and 65.0 mole% water is to be partially vaporized to produce a vapor that is 70.0 mole% acetone and a residual liquid that is 30.0 mole% acetone. (a) ...
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What would make a composite chemical vapor deposition diamond hard to make?

I am exploring whether a diamond based capacitor could be made for powering a drone. From my initial research, it has the right material properties (thermal conductivity, strength to weight ratio, ...
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1 answer
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Elution from an Ion Exchange Column

I am using concentrated NaCl(10%) to elute Cobalt (II) ions from a cationic exchange column. How would I determine the volumetric flowrate of regenerant needed to completely elute the cobalt ions from ...
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position of feed stream discharge in the fractionating column

In the book 'Chemical Engineering' by Coulson and Richardson (Volume 2, 5th edition), in the section 'Fractionating Column')(page-560), it's said that,'The feed stream is introduced on some ...
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using a coil for an electrochemical reaction

I wish to calculate the amount of energy required for electrolysis through induction, instead of electrodes. If there is a crucible metal core with solution inside and the coil wrapped around it. Can ...
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permeation properties of concrete under surface treatment

I wonder which permeation properties are critical in concrete with and without surface treatment (e.g sodium silicates-based solution) , is it air permeability,water permeability or absorption. If u ...
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What is the actual natural gas and electricity consumption of a Haber Bosch plant?

Plants running the Haber Bosch process provide the vast majority of nitrogen used in fertilizers. Collectivly, they consume about 3–5% of the world's natural gas production [...] (around 1–2% of the ...
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Verify parameters variation in local sensitivity coefficients for microkinetic model

I’m performing a sensitivity analysis for a model of a set of elementary chemical reactions. I’m considering the variation in species concentration ($c_{k}$) with respect to the forward reaction rate ...
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Corrosion of a galvanic couple made with silver and gold

If a bangle is made out of gold and silver, connected with each-other would there be a corrosion happening? If so can it be explained using the galvanic series? Also do those metals undergo oxidation ...
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Calculating the mass of CO2 from stack emissions

I am working on some calculation for an LCA of a plant. The plant has provided me a report that an engineering firm has measured the emissions from the stack. I am trying to estimate the amount of CO2 ...
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How can I check boiler blowdown sample line compliance with international code such as velocity= 1.5 to 1.8 m/s and flow 1000 ml/min

looking to cross verify this blowdown sample line with below given data against International code such as Velocity: 1.5 to 1.8 m/sec and flow 1000 ml/min. Data available: Location of sample line: ...
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Green Acetylene purifying material

Acetylene produced by carbide on water method, has some impurities like phosphine and hydrogen sulfide that has to be separated before filling the gas into cylinders. The purification methods can be ...
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Definition of partial differentiation of chemical potential with respect to the mole fraction?

I am trying to determine the double derivative of Gibbs energy with respect to mole fraction at the equilirbium from thermocalc. I know that the double derivative of Gibbs energy with respect to ...
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