How to calculate the area of a toluene exhaust condenser?
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In production, the toluene-containing exhaust gas that does not condense enters the exhaust system where it mixes with large amounts of nitrogen. This exhaust gas needs to be condensed again, which requires the use of an additional large-capacity cryogenic condenser. How should the partial pressure of toluene and the heat exchange area be calculated? Based on the volume percentage of toluene in the exhaust gas, when converted to 100% volume, does this correspond to the state pressure? Ask a question?
Partial pressure is the saturated vapor pressure of toluene at that temperature. The heat exchange area is calculated based on the amount of exhaust gas.
For toluene, under standard conditions its boiling point is 108.65 degrees Celsius; therefore, its volatility should be quite low. Additionally, the presence of a large amount of nitrogen seems to cause the pressure in the storage tank to change, which in turn results in toluene vapor being carried away as well. As a result, the proportion of toluene gas should be very low, meaning its concentration is low. Taking these two points into account, the efficiency of this approach is not high; it is recommended to conduct an evaluation first. If a cryocooler is indeed to be used, it is necessary to know the current concentration and quantity of toluene in the mixed gas. Then, based on the fact that the maximum efficiency of cryocooling is 80–85%, an estimate can be made of the concentration of toluene after condensation. As for the area required, it is advisable to convert the total gas flow rate into mass in order to determine the necessary area (for mixed gases, the specific heat capacity also needs to be taken into consideration)
First, calculate the partial pressure: log(pi) = 6.95464 – 1341.8/(219.48 + T). Then compute the saturated vapor pressure, and subsequently determine the heat exchange area based on the mixed gas
I can’t quite understand it! Could you explain it?