Thursday, January 30, 2020
Distillation Column Essay Example for Free
Distillation Column Essay The components that need to be separated are 1-propanol and 2-propanol. These two compounds are isomers with fairly close boiling points. They are separated based on their physical propertis. With the battch distillation might be almost impossible to do the sepapration. Capacity of the reboiler is 20 L. The Supply of pressure and steam is regulated by a newly-established controll system consisting of a steam pressure sensor, a Fieldpoint data communication and aquisition module from National Instrument, an electromagnetic control valve, and a LabView control algorithm designed by dr. Jang. The data was taken frm one of the six computers near the column which had the control algorithm. The Fieldpoint module needed to be connected with the column via Internet. In this column at different stages there are 10 thermocouples (K type) inserted in each tray. Manual steam valve open 40%. Proportional gain or band (Kc) 2 Integral (reset) time ( Ti min) 0. 2 Derivative (rate) time (Td min) 0 Steam pressure set at 9 psig. Used Peng Robinson model Inside the column, the downflowing reflux liquid provides cooling and condensation of the upflowing vapors thereby increasing the efficacy of the distillation column. The more reflux is provided for a given number of distilaliton plates, the better is the columns separation of lower boiling materials from higher boiling materials. Conversely, for a given desired separation, the more reflux is provided, the fewer distillation plates are required as in our cases 8 plates. A reboiler at the bottom of the distillation column provides the heat needed to generate the upflowing vapors inside the column. The reboiler can be a heat exchanger. Fig. 1 The liquid feed mixture to be distilled 1 propol and 2 propanol is placed into the round-bottomed flask along. As the mixture is heated and boils, vapor rises up the column. Some of the vapor cools and condenses on the glass platforms (known as plates or trays) inside the column and runs back down into the liquid below, thereby refluxing the upflowing distillate vapor. The hottest tray is at the bottom of the column and the coolest tray is at the top. At steady state conditions, the vapor and liquid on each tray is at equilibrium. Only the most volatile with hte lowest boiling temperature of the vapors stays in gaseous form all the way to the top. The vapor at the top of the column then passes into the water-cooled condenser, where it condenses into a liquid. The process continues until all of the most volatile components in the liquid feed boil out of the mixture. When a liquid mixture 1 propanol and 2 propanol is heated so that it boils, the evolved vapor will have a higher concentration of the more volatile 2 propanol (i. e. , lower boiling point) components than the liquid mixture from which it evolved. Conversely, when a vapor mixture is cooled, the less volatile components tend to condense in a greater proportion than the more volatile components. The heated feed is partially vaporized and rises up the column. However, as it rises, it cools by contacting the descending cooler liquid and partially condenses so that, while part of vapor continues to flow upward, the condensed portion is enriched in the less volatile component(s) and flows downward. As the vapor continues to flow upward, it undergoes partial condensation a number of times and each time becomes richer in the more volatile component). The column is kept at steady state temperatures, pressures, and compositions at every point within the column are essentially kept constant during operation.