How is the ethanol content in the exhaust gas from the ethanol venting system calculated?
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I want to use a 2% ethanol solution as an absorbent to absorb ethanol exhaust gas, but when calculating the absorption tower, the molar ratio of the solute components in the inlet gas is unknown, which prevents further calculations from proceeding. I hope a senior can tell me the calculation method. If I use the gas-liquid equilibrium equation to calculate the partial pressure of ethanol vapor in a tank containing 70% ethanol, what value of y does this give: the mole fraction of ethanol in the gas phase relative to ethanol + water, or the mole fraction of ethanol relative to ethanol + water + air?
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If you don’t even know the exhaust content, it’s indeed impossible to calculate it. Secondly, the components inside your container are a bit complex – how is there still air there? Isn’t it an ethanol-water equilibrium mixture?
The ethanol content has been calculated based on solvent loss, but how is the equilibrium line for the ethanol-water absorption tower determined? It should be different from the equilibrium line of the ethanol-water distillation tower, right? Does temperature affect the equilibrium line of the absorption tower?
It must be different. Relevant manuals (such as petrochemical design manuals) can be consulted to determine the equilibrium partial pressure curve. Temperature and pressure both have an impact.