Questions tagged [chemical-engineering]

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

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Calculating enthalpy of incompressible liquid and ideal gas?

I have been tasked with creating a Mollier diagram for water using the Redlich-Kwong EoS. In order to calculate the real enthalpy and entropy values using departure functions and residual properties I ...
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Continuous stirred-tank reactor (CSTR) in parallel problem

I am having a difficult time solving the following problem. The only thing we learned in class was parallel continuous stirred-tank reactor (CSTR) with equal-sized reactors and equal flow rates for ...
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Single Stage Equilibrium Problem

I am working on this problem below. Two lb-mol of an equimolar mixture of ethanol-water that is a vapor at dew point at 14.7 psia is mixed with 4.09 L water ($\rho$ = 1 g/ml) at $60^o F$ in an ...
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Is half of depletion region a part of N region or P region?

Is it correct to say that if the P-N junction is in the middle of the depletion region, half of the depletion region is for the P region and the other half is for the N region?
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Why heat transfer happens only via conduction in this case?

Why heat transfer between a heated flat plate and a fluid happens via conduction only and not convection, when the fluid is present below it? Consider a plate under which a fluid is present and it ...
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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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Mean temperature of a fluid in a pipe

Consider a pipe in which a fluid flows such that the pipe is at a higher temperature than the fluid. At any cross section of the pipe we get a varying temperature profile. We can define a mean ...
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Size characterization

Which technique can I use to characterize the size of my particles? They would be in the range of 50 μm to 300 μm. I have verified using a microscope, but I need a technique to analyse the size ...
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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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How to calculate the logarithmic mean temperature difference of a jacketed vessel?

I'm a bit confused on how to calculate the $ \Delta T_{LM}$ of a jacketed isothermal CSTR. Because the formula for the logarithmic mean temperature difference is: $$ \Delta T_{LM} = \frac{\Delta T_{...
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Extraction Flash Calculation - 4 Component and 2 Phase System

I am performing extraction flash calculations for 4 component and 2 phase system in Matlab. For anyone somewhat shaky with what extraction flash calculation is; extraction is performed, feed ...
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Packaging Fresh Fruit in Aluminum Cans but still spoiled after 7 days

I am doing small experiment where I put fresh fruit inside a standard aluminium cans, then use an industrial seamer to close the lid. I also put juiced version of it (with only water and sugar) in ...
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What methods should I use to calculate the size of a moving grate incinerator

I have been tasked with calculating the size of a moving grate incinerator for a college project. I have calculated the mass and energy balances for the waste to be burned on the grate, but I am ...
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How to calculate the amount of fuel required and time to preheat a furnace's combustion air to 850 C

I am designing an incinerator to combust MSW producing a flue gas of 1000 °C. A requirement of the furnace is that the air inside must be preheated to 850 °C through the use of auxiliary fuel burners ...
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Why is the fluidization pressure drop profile different when this one is measured while increasing and decreasing fluid flows?

why is it that when measuring pressure drop across a solid particle bed at different fluid flows the pressure drop profile looks different? When you measure pressure drop while increasing fluid flow, ...
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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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Can you use an equilibrium reactor to determine the conversion of an equilibrium reaction, and then use that conversion in a conversion reactor?

I'm trying to model a reaction in Aspen HYSYS, and was wondering if an equilibrium reactor can determine the conversion of an equilibrium reaction, and then using that conversion for the forward ...
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Can carbohydrates in powdered form provide a more 'energy efficient' alternative solution to traditional combustion engines? [closed]

In my high school chemistry class I am studying the affect of surface area over the rate of reaction. In this case, using Collision Theory to describe how a high surface area to volume ratio ...
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Why not use sodium hydroxide to reduce carbon dioxide emissions?

The products of the reaction are useful. Renewables like solar power can be used for the electrolysis of brine. I don't understand why petrochemical companies are not using it as a scrubber?
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Reaction of Components with Methyl Ethyl Ketone makes it corrode. How to prevent?

I have an issue with chemical plating of Iron, the component is immersed in Methyl Ethyl Ketone for a time span and then Zinc galvanized plating starts to corrode. I am not understanding what measures ...
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derive functions for generating projections for the interpenetration of two cylinders for making fittings

​ I want to make custom fittings for constructing large molecular models using copper tubing. I will need to cut a hole in one piece of tubing that will closely fit around another inserted piece. I ...
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How come there is no home clean incinerator/burner yet?

I realized recently that burning waste oil, plastic, coal, even plain wood, release (potentially) harmful SOx, NOx, and particulate matter (wiki) That's why it's mandatory for incinerators / boiler-...
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What is the input pressure and a suitable feed composition for a Peng-Robinson EOS Python program?

It's a strange question, I know. Essentially I am supposed to use a Python program to generate VLE data for a binary mixture. I have the components and their critical values (Tc, Pc, acentric factor), ...
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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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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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Is there any way to quantify the rate at which pressure is relieved in a reactor?

If a pressure relief valve is open, is it somehow possible to quantify the rate at which the pressure in the reactor will decrease?
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Does the quality of steam affect the efficiency of a turbine to be calculated?

We were presented in one of our lectures this problem. A steam turbine operates adiabatically at a power level of 3500 kW. Steam enters the turbine at 2400 kPa and 500°C and exhausts from the turbine ...
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What are some chemical reactions that failed to scale up? [closed]

Also, what happened to the reactions after they failed to scale up? Were they commercialized? Sold?
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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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How to model the kinetics of a reaction while its not being stirred in a batch reactor?

lets consider the following reaction: $$ A + B \rightarrow C $$ Where the rate of reaction ($r$) can be expressed as: $$ r = k*c_a*c_b $$ Where $c_i$ is the concentration of species $i$ and $k$ is the ...
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Preventing leakage in sludge tank

I recently went on a tour to a local water company plant where we were shown a sludge tank which is where the sludge in the water is removed and stored here. The sludge can be acidic and so can cause ...
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Handling the source term in the convection-reaction-diffusion equation

The 1D convection-reaction-diffusion equation for solute transport is given as: where C is the concentration, v is the flow velocity, D is the diffusion coefficient, S is the source/sink term, and R ...
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Nozzle inlet and outlet diameter for a shell and tube heat exchanger

Hi I have designed a shell and tube heat exchanger to cool octane and water. I have all the dimensions but I was unsure which equation to use to calculate the diameter for the inlet and outlet nozzles....
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Plug Flow Reactor Concentration UDF Debugging

I'm new to CFD and I'm trying to write a UDF that calculates the concentration at any position as a function of its x-coordinate (for example, Ca = .5C - .1x, or dCa/dx = -kCa). This is my first time ...
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Thermal conductivity and the second law

I am having trouble figuring out the solution for part d. Can anyone give me a hint?
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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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1 answer
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CO2 production from sugar [closed]

Greenhouses often use burners for CO2 enrichment, which requires a source of liquid propane or natural gas. The yeast fermentation process can also be used to create CO2 for a greenhouse by supplying ...
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More temperature after boil the water can cook more faster the food?

My Question was not well received in physics.stackexchange.com and I get a simple answer when I want to know the theory inside this question. I want to cook more efficient wasting less ( gas or ...
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How do you imagine momentum?

If you want to explain it to a layman (who belongs to the science stream ofc!!) how do you explain it? Also, what is momentum transfer when it comes to fluid mechanics?
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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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How to model a condenser (heat exchanger) where both streams are two fluid mixtures?

As mentioned I would like to model a heat exchanger (using Python). In this case, the condenser/hx streams are both a mixture of O2 and N2 These are known for both streams: Inlet temperature Inlet ...
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Calculating gas volume in a gas-liquid system/pressurized vessel

There is water in a tank and the tank is connected to a piece of piping that has a volume of 2.5L. The headspace above the water is pressurised by using air, to a pressure of 3 bar (a). What happens ...
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Aluminum or Copper, which one is better to control and maintain the temperature?

Friends, I am an EE/SW/Controls eng. Please, pardon me of perhaps incorrect terminologies. I am working on a R&D project: A chemical lab equipment has a 2" long metal pipe enclosed in ...
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Why are there no propane refrigerator air-conditioning units that run on solar heat?

I was thinking about how hot it was outside, when a thought came to me. There are propane refrigerators, so why not replace the propane as the heat source with solar heat and then change it from a ...
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3 votes
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Is there a maximum life for things made out of stainless steel or cast iron?

Do steel objects have a maximum lifespan? I read that "316 stainless steel is estimated to last for 1200 years in a “rule“ environment before heavy pitting. In the marine environment this is ...
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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 are some books/academic journals which I could read on renewable energy/technology? [closed]

Book suggestions on renewable energy technologies/sources
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Industrial recycling of mirrors

I learned recently that mirror is mostly manufactured by pouring thin metal coating (i.e alumunium) on top of a substrate surface (i.e glass), Due to the nature of this composition it cannot be easily ...
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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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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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