# Questions tagged [chemical-engineering]

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

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25 views

### Kinetic Procedure Data in PRO II Software

I am currently using PRO /II to simulate NH3 decomposition for a school project, and currently have been trying to input the reaction kinetic (https://imgur.com/OYqfiQE) to the Procedure Data. I ...
45 views

### Evaporation of water using a vacuum pump - COMSOL

I'm using COMSOL to simulate a system where liquid water is evaporated using a vacuum pump, but I am struggling to understand the mass transport process of vapor from the liquid-air interphase to the ...
31 views

### Legend or not: wood coat should "breath"?

I am going to stain some pine boards, then coat them with boiled linseed oil. The latter should let moisture to diffuse through (correct me if I am wrong), but the water-based stain produces poorly ...
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### Reactor with mixing and a cooling jacket

Suppose we have a reactor with mixing that contains a known quantity of water at $121^{\circ}C$ (due to the pressure, the water is liquid). We want to cool the water to $37^{\circ} C$ by using cooling ...
24 views

### Why don't Steam-Methane Reformers have pilot burners?

Reformers like other fired furnaces burn fossil fuels usually naphtha or natural gas to provide the heat required for the reaction (steam-methane reforming, in this case). However, unlike other fired ...
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### How to derive the relation of a and b according to critical points (including compressibility factor) from Peng Robinson EoS

I've been trying to prove the relation of a and b according to critical points of PR EoS: prove that a and b are: a = 0.457 (R^2T_c^2)/p_c , b=0.0778(RT_c)/p_c I tried to prove it by doing the partial ...
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### Recycled brine flow rate

How to find the water flow rate coming out of a pump? The flow rate entering the pump is 471 t/h. The pump's pressure is 3.6 bar.
48 views

### Could a de-commissioned synthetic ammonia plant be adapted for use in removing atmospheric C02 (DAC?)

I was prompted to ask this question by viewing a disused NH3 plant in the harbour near where I live. Like many it functioned using a methane feedstock from a natural gas find off the coast. I happen ...
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### I'm struggling to manipulate the necessary equations to find the final temperature and pressure

A perfectly insulated tank is divided into two identical chambers separated by an internal membrane. One chamber contains methane at 500 bar and 20 °C. The other chamber is evacuated (contains nothing)...
130 views

### How to work out the kWh required to compress hydrogen gas?

I am trying to work out the kWh/kg of compression of hydrogen. I have used the isentropic compression calculations and get values for the entropy but am unsure how to get this to a kWh value. I might ...
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### Unit conversion error - Darcy Radius of Well Influence Equation

I'm having a little trouble. I'm trying to convert the answer from imperial to metric but can't seem to get the answer to match. I am using the formula attached (Darcy Radius of Well Influence ...
1 vote
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### Chemical oxygen generator [closed]

3enter image description here Why airborne chemical oxygen generator has shelf life? What causes deterioration of the generator which are not used during long time? The generator comprises Sodium ...
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### Will petroleum jelly degrade silicone elastomer?

I have gotten conflicting information on this question. If I put a bit (1/4 of a cc) of vaseline on a silicone elastomer part and then apply gentle pressure for hours will this degrade the elastomer? ...
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### Behaviour of a mixture of ideal gases

If we have a mixture of ideal gases can we consider the mixture also an ideal gas? This holds true in air for example where we consider it an ideal gas, when oxygen and nitrogen are considered ideal. ...
1 vote
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### Is mechanical work done when the valve of a filled gas cylinder is opened for gas to flow through the pressure regulator and connecting line?

I am trying to calculate the final pressure and temperature in the pressure regulator and connecting line of a gas cylinder when the valve is open to pressurize the line.
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### What kind of test should I run for a newly built lab scale reactor assembly?

I am a new graduate student working in thermochemical energy storage research. I have built a lab-scale model reactor for running hydration reactions. My advisor has asked me to run test of the ...
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### How to solve a multi-step mass balance

I have a problem, where I'm trying to solve the mass balance of a multi-step process with limited information available. What I have is a material supply of known flow and composition. This supply is ...
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### What is Drift flux in two phase flow (Fluid Mechanics)?

I recently started learning about two phase flows. While studying I came across relative velocity, drift velocity and drift flux. I understand the first two terms, but I don't understand the concept ...
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### Is there any special coating or paint that will strongly bond to an automobile tire's tread and can be driven on?

I would like to know if there is any special coating or special paint that can be applied to the tread of an automobile tire, strongly bonding to it, and which is strong enough and durable enough to ...
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### How to add compressor curve in Aspen HYSYS for a centrifugal compressor with IGV and only one efficiecy 65% is given in data sheet at 400rpm

I am trying to check the adequacy of existing centrifugal compressors in a gas train. The adequacy check is required due to a new tie-in in an existing gas train inlet, from a new source of "...
125 views

### How do I calculate effectiveness and NTU of a heat exchanger when there is phase change?

This is my first post here. I explain the big picture of my current circumstances, I am a software engineer currently making a platform for evaluating process equipment in plants. I do not really know ...
46 views

### Calculating Fractional Yield as a function of temperature for a parallel reaction in a plug flow model

(This question comes from a Chemical Engineering background, I hope it still falls in the scope of engineering.stackexchange.com If not, please move.) I am trying to calculate and plot fractional ...
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### Chemical Process Control - degrees of freedom in a stirred tank heater

I'm taking a course on Process Control, and I've been using Stephanopoulos's Chemical Process Control to study. I have a doubt about the degrees of freedom (DOF) analysis performed in one of the ...
154 views

### Using the electrolysis of water to cool a room

Browsing the internet yesterday I came across this very esoteric paper which purports to describe the construction of a device which uses the electrolysis of water into hydrogen and oxygen (a highly ...
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### How do I calculate magnitude of shear force per unit of length when all I'm given is the diameter?

I had a chemical engineering homework problem where I had to come up with a velocity profile for methanol flowing through a cylindrical tube, where viscosity and average velocity were given, but the ...
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### What materials where used in this study or ones that would make the most sense please!

I understand that they used two different materials and combined them through fiber drawing process but I don’t truly understand which materials were used. Here is where it is mentioned in the article....
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126 views

### Gas leak rate from a pipe

I am trying to find out how to calculate the leak rate of gas (composed of mostly methane at around 30degC and 150psi) from a pinhole leak (~5mm) to the atmosphere in a pipe where you do not have the ...
1 vote
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### How to safely experiment with wood pyrolysis?

I have been thinking about how to make a carbon negative BBQ. The idea would be, use sustainably grown wood (so you start nearly carbon neutral) and pyrolyse some of it, and bury the resulting carbon....
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320 views

### Calculate surface area of batch reactor

I have calculated the volume of reactor for 30000 tpa product also its diameter and height and its volume is 86 kL. How to calculate the surface area of the same reactor to check requirement of heat? ...
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### How would nanobots disassemble something on a molecular level?

I've been studying this topic for use in a story I'm working on and I've come across various videos and interviews on the topic, but they all seem mostly concerned with assembly of larger objects. I ...
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### How does an Eductor work?

Am currently learning P&ID diagrams. I came across the term ‘eductor’ and I’m trying to understand its working. Apparently, it’s different from an ejector in the sense that it draws the fluid in. ...
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### How is the electrolyte stored in an Alkaline Fuel Cell?

Every type of fuel cell has a catalyst and an electrolyte to carry electrons between the cathode and anode. What I don't understand is how the electrolyte is stored in a Alkaline Fuel Cell. In essence,...
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### Turbulent flow, fluctuating part of velocity

Let's say we have a fully developed turbulent flow on x axis (simple shear flow). Time-averaged components of velocity on y and z axis are 0. If a lump of particles is moving upwards, then the ...
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### what is effect of temperature on dew point?

I read that relative humidity changes with change in temperature though there can be constant humidity. So, if RH is changing then dew point should get increase with increase in temperature? https://...
1 vote
315 views

### How to calculate the flow rate and kinetic energy of gas flowing in a pipe given its density, the pipes diameter and its velocity

I've been given a question which asks to calculate the kinetic energy of gas flowing through a pipe given the density(kg/m^3), pipe diameter(m) and velocity(m/s). I'm first required to find the flow ...
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### Calculating the mass flow of water vapour in a boiling pot. A little help with mass and energy balances needed

Suppose that I'm boiling water in an open pot. As the pot is heated by the stove, it loses mass in the form of vapour. The pot is my control volume. That system could be modeled by the following ...
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### Tanker exhaust sequence blows sulfuric acid everywhere and I need to rig up something to slow the exhaust without impeding flow rate

I am not an engineer myself and I'm hoping you guys can help me with a project I am working on. So we receive rail car tankers full of sulfuric acid that we pressurize like a beer keg to offload the ...
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### How the choice of etchant can affect the severity of hydrogen embrittlement during pickling and passivation?

Following this question, I am trying to understand how/if the choice of acid we might use during the pickling and passivation of certain metals, can influence the severity of hydrogen embrittlement. ...
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1 vote
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### What will be the destiny of the oxygen gas created in the future hydrogen economy?

When I was recently studying biomass-to-electricity (gasification methods, Drax power station...), I was wondering whether the efficiencies of these systems would not benefit from a source of pure ...
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### Orange spots at hot dip galvanized surface

I like to ask you about orange spots after galvanizing of Steel Purlins. I attached some of the pictures. Please advice the solution with your expertise. Thank youenter image description here enter ...
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### Integrating the Onsager formulated mass transport equation for a binary mixture

I want to develop a model for the Maxwell-Stefan mass Diffusion for a binary mixture for a nano porous membrane. I have permeation data and adsorption isotherms measured I just need to implement the ...
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### Heat transfer in open equalization tank

I have to cool waste water in equalization tank (open tank) from 60 C to 30 C. Here is the information about the waste water: [![enter image description here][1]][1] [1]: https://i.sstatic.net/QqiSG....
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### Enthalpy Of Water vapour at room temperature

I am wondering how to calculate the enthalpy of water vapour at room temperature with a reference state of 25 C 1 atm. I understand that normally for water vapour above boiling point, one would ...
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### Double Meniscus of Capillary Tube

I recently realized that if I turned my coffee cup downward, all the liquid spills out easily. This amazement prompted me to wonder about the impacts of surface tension for a situation in which the ...
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### After how many days can concrete framework be removed?

After how many days can concrete framework be removed? Do admixture chemicals like superplasticizer or accelerating admixtures allow early removal of concrete framework?
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### Is there a filtration mechanism that allows nicotine molecules to pass and not particulate matter?

I was wondering if an equivalent of the vaporization of tobacco could be achieved by normal combustion but passing the smoke through a filtration mechanism that only allows pure nicotine vapor through ...
1 vote
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### Solar distillation of sump pump water and the issue of Radon gas

Lately I have been thinking about designing and building a solar-powered water distiller that would be placed close to my house in my backyard. One thought that I have is installing a bypass valve on ...
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### Is there a reason to connect tube reactors in series?

With CSTR (continuous stirred-tank reactor), it is in many cases benificial to connect multiple CSTR in series. I wonder if there is a purpose for tubular reactors to be connect in series as well?
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### How much Energy is Radiated by a gray body?

How much energy is radiated by a gray body at an ambient temperature of T Degrees Kelvin, between the wavelengths of w1 and w2 micrometers , if the emissivity of this gray body is 0.6 ? (Note: ...
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### Why do Nickel Manganese Cobalt batteries wear out before Lithium Iron Phosphate batteries?

Do NMC batteries lithium plate faster? Does the Solid Electrolyte Interface (SEI) grow faster on NMC batteries? Do they heat up more and therefore the SEI grows faster? Does the Iron stabilize the ...
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