Read about evaporation | 24 Discussions | Page 1

  1. StoningTree

    Cooling with Evaporation

    First i calculated the latent heat of vaporation: h_vap(15°C)= 2465.4 kJ/kg In the next step i calculated how much water is already in the air: x=0.622*j*ps/(p-j*ps)=0.00988 kg/kg where: j=50% ps=0.03171 bar p=1.01325 bar Now that i know that i can calculate the enthalpy of humid air: h_hum =...
  2. V

    Mathematical Modeling of an evaporator for evaporating water

    I am trying to model an evaporator which evaporates water to steam in Matlab/simulink. Are there any governing equations i need to know and follow when modelling the evaporator mathematically? Please let me know.
  3. SpinzTronics

    Help searching for SAMs (self-assembling monolayers) for a project

    Does anyone know of a self-assembling monolayer that can bind to triethylamine,deposit onto graphene/TMD by evaporation, and that has "low toxicity" (that I could use in the lab)? P-dopants could only help dope one side of the material and TEA would react on the other but that is very hard to...
  4. Guilherme Franco

    How volatile is urea in a water mixture?

    I'm seemingly having problems of having too much evaporation of urea in the preparation of a gel. The gel is formed by drying the components in a water mixture, and it takes hours to dry at 70 ºC and dries much faster at 100 ºC (also produces a gel with better consistency), but at 100ºC it seems...
  5. EEristavi

    I Liquid boiling and Evaporation

    In the normal conditions (sea level) water evaporates at 100 C. In thermodynamics, we say: the amount of energy Q, can raise temperature of the liquid by the formula Q1=cm(t2-t1); when the liquid reaches the boiling point (100 C), we write Q2=Lm. Q2 is entirely spent on changing liquid state...
  6. J

    I Evaporation under vacuum; surface area

    I run a vacuum distillation unit that is used to distill ethylene glycol. The old glycol is subjected to 25Hg of vacuum at a temp of 275 degrees F. There are burner tubes submerged in the glycol to heat it up. The vessel has a diameter of 36 inches and is 124 inches long. We fill the vessel...
  7. V

    How calculate the Heat flux requiered to evaporate sub cool water

    Homework Statement I was trying to validate a calculation I didusing ANSYS fluent, it's about a flow of water that enters a tube, the tube is 16m long and is being heated with a Heat Flux of q'=1077328,47 [W/m^2], now after the simulation runs and I check the results I find out that the steam...
  8. C

    Calculate the moisture content of air

    Homework Statement (Simplified) During tests at cliffside power station, the following data was recorded from the cooling tower. A cooling tower has a 9 cell draft design, each diameter is 10m. Data D_o = 10m V_exit = 14.4 m/s T_exit(15 celsius) = 288.15K Ambient conditions : T(15 celsius) =...
  9. D

    How to avoid boiling/bubbling effect under vacuum?

    I have a process problem where my product is mixed with water and needs to be separated under low temperature range 5-10 deg C. I hope evaporation under vacuum is the only solution but the boiling effect is creating splash and want to avoid it. Prefreezing or lyophilization is not an option...
  10. Adrianus

    What heat capacity is needed to evaporate water in oil

    Homework Statement In an industrial fryer is f.e. 400 kW. Heating capacity installed. The fryer may contain as much as 1.450 ltr of oil. I can fry 2.000 kg of chicken nuggets per hour in that. These products loose 7% of moisture/water in this process. That water can only escape from oil in gas...
  11. S

    Clothes Drying (Evaporation) Equation

    I am trying to find the most efficient way to dry clothes indoors with different evaporation factors 1. Heat/Temperature 2. Airflow 3. Humidity 4. Light (Electromagnetic energy) But I am not sure what equation to use. (mass loss rate)/(unit area) = (vapor pressure - ambient partial...
  12. Umar Awan

    Fractional distillation calculations

    Say I have got a super cooled cylinder of half hydrogen and half helium. This cylinder has a pressure of 100,000 Pascal's. At this pressure, hydrogen boils at 20 Kelvin and helium at 4.21 Kelvin. I hope to separate helium by cooling gas down to 4.21 Kelvin but I know that even at the...
  13. jmarkwalker

    Evaporating water using heat and reducing vapour pressure

    I want to reduce the amount of water present in the digestate coming out of my Anaerobic Digester. The traditional method would be to boil it until I've removed as much off as I want. However, this is expensive from an energy consumption point of view. There's a great video on Youtube showing a...
  14. K

    I How can water evaporate?

    Some facts: Water does evaporate. The average kinetic energy of a water molecule at 373 K is ~0.03 eV The average strength of the H bond is ~0.24 eV In the liquid phase the average H2O molecule is bound by 2 to 4 H bonds...
  15. C

    How can I recreate this pressure boiling experiment

    Hi all, I was just wondering how I could recreate this at home What parts do I need? Thanks, Harry
  16. M

    Rate of evaporation

    Hi I was thinking of doing an experiment for my maths coursework to plot a graph to, and was thinking of doing something related to the rate of evaporation of water. My thinking is that i conduct an experiment where I heat water to boiling point so it is at about a constant temperature with a...
  17. P

    Psychrometry question

    As we all know that in atmospheric pressure (1 Bar) saturation temperature of water is 100 deg C. And the air contains mixture of dry air and water vapour. My doubt is here that the water needs 100 deg Celsius to change from liquid to vapour state then how can a normal room temperature air...
  18. Ornit

    Ion Assisted Deposition (coating technology)

    Hi all, When talking to some of our optics vendors, I got the impression that Ion Assisted Deposition (IAD) is standard. We use our optics at high power densities and we care about laser damage as well as adhesion and density of the coating (aka porosity, helps reduces sensitivity to humidity)...
  19. K

    Fuel evaporation in a tank - Pressure calculation

    Hello everybody, I have the following problem: I have a fuel tank, with a liquid phase (the fuel) and gas phase at To and P0, where T is temperature and P pressure. I assume that the gas phase at the instant t=t0 is air. (Is this assumption correct?) The temperature of the liquid phase...
  20. 3

    Effect of evaporation on RH

    I hope it is ok to post a rather pedestrian question to those of you who may laugh. We own a vacation home in Phoenix and continually folks insist we should leave pails of water in the house while we're away to help raise the RH and keep construction materials from drying out, cracking etc. This...
  21. U

    Is an asthma inhaler (MDI) an example of vaporization?

    I am trying to give some context to medical vaporizers in a literature review I am composing and initially decided to give asthma inhalers and nasal inhalers as examples. I realised however, that some sources on-line were referring to these metered dose inhalers as vaporization devices when...
  22. MexChemE

    Psychrometry -- Ethanol in dry air

    Homework Statement Ethanol evaporates in a 10 x 20 x 50 ft3 room. Air is initially dry at a temperature of 30 °C and 765 mmHg of pressure. a) If the partial pressure of ethanol after vaporization is 40 mmHg, how many pounds of ethanol evaporated? b) The same air is compressed until it reaches a...
  23. C

    How far water flows in a tilted oven before evaporating?

    If I throw 10 gallons/minute of cold water for 4 days into an oven that's 300°C Celcius and 300ft long sloped at an angle of 10°, how far would the water make it down the oven before completely evaporating? Even if you can't solve this directly, I'd love some advice or recommendations of how...
  24. duran9987

    Cooling liquids by blowing

    I just began reading Feynman lectures and it turns out that during evaporation, water molecules that move faster than average (higher temp) break away from the attraction of their neighbors leaving behind molecules that move slower than average (lower temp) and result in a cooler liquid. When a...
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