Condensers, Direct Contact Condensers, and Vacuum pumps.
Some control devices and process equipment operate in such a way that contaminants are removed from the exit vent stream by way of a phase change from the vapor to the liquid. In most cases the liquid consists of only a single phase, although two separate liquid phases can be encountered.
When the control device (such as a condenser, direct contact condenser, liquid ring vacuum pump) operates due to a phase change from vapor to liquid then Emission Master applies equilibrium and material balance considerations to calculate an answer.
1. The material balance around the equipment item is assumed to remain constant. The process inlet streams (liquid and vapor) are equal to the exit streams (liquid and vapor).
2. Single stage equilibrium concentration between the exiting liquid and vapor streams are maintained for all condensable components. For example, if the process contains methanol, water, and ethanol then the partial pressures in the exit vapor stream are calculated to be equal to the vapor pressures in the exit liquid stream. If the exit liquid stream contains two liquid phases then these two liquid streams are calculated to be in equilibrium as well.
3. Air, nitrogen, or other non-condensable gases in the system are considered to exit the equipment entirely through the exit vapor stream.
4. Emission Master enables the user to specify activity coefficients for each compound in the system for each liquid phase. This flexibility enables the program to determine presence of two phases in the exit liquid.