Volume change of methanol after dissolving gases
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Please tell us how much the volume of methanol changes after gases are dissolved in it, especially during the process from a methanol-poor state to a methanol-rich state! ?
It depends on the amount of gas absorbed.
When low-temperature methanol absorbs gases until saturation, its volume can increase by about 10% to 20%. The amount of absorption varies depending on the temperature, so only an approximate range can be specified
After some calculations throughout the afternoon, a rough result was obtained; please let me know if there are any mistakes! 1 mol of methanol is present. -13.2 Density of pure methanol: =(0.7918 – (-13.2 – 20) * 0.00098) = 0.824336. Volume: 32.04 / 0.824336 = 38.86765. Density after saturation with CO2 at -13.2°C (mole percentage: 28.63%) = 0.7902024 * (1 + 13.2/240) – 0.8629823 * (1 + 13.2/240)^2 + 0.8718538 * (1 + 13.2/240)^3 = 0.896909. Mass = 0.2863 * 44 + 0.7137 * 32.04 = 35.46415. Volume = 35.46415 / 0.896909 = 39.54039. Therefore, the rate of volume change: (39.54039 – 38.86765) / 38.86765 = 0.017308
Based on on-site measurements, the general volume increase does not exceed 5%.
It hasn’t been tested, but it is known that the volume of poor methanol increases significantly after it dissolves acidic gases.
Friend, where do you get your views from?
I took another look at this problem today and realized there was an error in my calculations. Since no one else brought it up, I’ll correct it myself! After some calculations throughout the afternoon, a rough result was obtained; please let me know if there are any mistakes! 1 mol of methanol-rich mixture is present. -13.2 Density of pure methanol: = (0.7918 – (-13.2 – 20) * 0.00098) = 0.824336. Volume: 32.04 * (1 – 0.2863) / 0.824336 = 27.74. -13.2 Density after saturated absorption of CO2 (mole percent: 28.63%) = 0.7902024*(1+13.2/240) – 0.8629823*(1+13.2/240)^2 + 0.8718538*(1+13.2/240)^3 = 0.896909. Mass = 0.2863*44 + 0.7137*32.04 = 35.46. Volume = 35.46/0.896909 = 39.54. Therefore, the rate of volume change: (39.54–27.74)/27.74 = 42.54%. Last edited by z880347730 on 2009-3-21 20:43.]
The volume of methanol increases after absorbing gas, but there is no fixed value for exactly how much it increases! The increase in volume is related to factors such as absorption temperature, pressure, gas composition, and the purity of the methanol-poor mixture!