Gas phase composition of a sealed reactor
Thread Content
1. The empty reaction vessel is filled with nitrogen; ethanol is then added. Under sealed conditions, the pressure continues to rise. When the pressure reaches 2 bar, the addition of ethanol is stopped. The current temperature inside the vessel is 40°C. Assuming equilibrium has been reached, how can the composition in the gas phase be simulated? 2. After some time, nitrogen is introduced into the reaction vessel to bring the pressure to 3 bar, while the temperature inside the vessel remains at 40°C. What is the gas phase composition at this point, and how can it be simulated?
1. First, it is necessary to know the vaporization temperature of ethanol and that of nitrogen. Assuming that ethanol vaporizes completely at 40°C and ignoring its solubility, at a pressure of 2 bar, the components in the gas phase are ethanol and nitrogen. According to thermodynamic principles, the mole fractions of ethanol and nitrogen in the gas phase can be calculated using the ideal gas law, namely n_ethanol/(n_ethanol+n_nitrogen) = P_ethanol/(P_ethanol+P_nitrogen), where P_ethanol and P_nitrogen are the partial pressures of ethanol and nitrogen, respectively. 2. After adding nitrogen, ideally, the gas phase composition should consist of nitrogen and ethanol. Similar to the first question, the molar fractions of ethanol and nitrogen in the gas phase can be calculated using the ideal gas law. Since nitrogen is already present at this point, the initial nitrogen partial pressure needs to be taken into account. It should be noted in the calculations that, since this is a closed system, the total number of moles of material must equal the total number of moles of nitrogen and ethanol initially added. .
Determine the total amount of nitrogen, x kg, and the total amount of ethanol, y kg, inside the closed tank respectively. Then, in ASPEN, create a flash model using x kg/h of nitrogen and y kg/h of ethanol. The equilibrium data will correspond to the gas-liquid composition within the closed tank. 2 Similarly