Batch Distillation Column

UNIVERSITY OF ENGINEERING AND TECHNOLOGY LAHORE Department of Polymer and Process Engineering Batch Distillation Column Mass Transfer Laboratory Submitted to: Sir Sajid Naseem Submitted by: Muhammad Khizar Shafique 2011-PE-67 Muhammad Umer Farooq 2011-PE-41 Zohaib Ahmad 2011-PE-64 Nabeel Ahmed Khan 2011-PE-57 Muhammad Imran 2011-PE-70 Dated: 04-03-2014 Table of Contents 1. Experiment Report ...................................................................................................................... 1 1.1 Introduction........................................................................................................................... 1 1.2 Procedure .............................................................................................................................. 1 1.3 Calculations ........................................................................................................................... 2 2. Types of Trays (Plates) in Distillation .......................................................................................... 3 2.1 Bubble Cap Tray .................................................................................................................... 3 2.2 Valve Tray .............................................................................................................................. 3 2.3 Sieve Tray .............................................................................................................................. 4 References ...................................................................................................................................... 5 1. Experiment Report Use of the refractometer to find out the composition of mixture obtained from Batch Distillation Column 1.1 Introduction The experiment is carried out by the use of a batch distillation column. At first the values of various parameters are calculated by the use of distillation column. The separated sample is collected from the tank in a beaker. It is then used in a refractometer to measure the refractive index of collected sample. The experimental procedure is as follows. 1.2 Procedure A mixture of ethanol and water is used as sample. The sample is added in a batch tank. The batch distillator is then turned on and the apparatus then runs according to the given parameters. The water and ethanol vapors are separately collected in tanks. The ethanol is then taken from the tank in a beaker. The sample is taken in a refractometer and refractive index is calculated. The refractometer measures the critical angle of the liquid under test and each concentration will show a different critical angle. From the refractive index and other parameters like molecular weight and density, we can accurately calculate the concentrations of both components of sample mixture. Refractometer has to be handled carefully, especially when it is analog type. Make a thin film of liquid on the glass slide in front compartment. Then close the compartment and adjust the right reflection angle of light source reflector. Then adjust the resolution of screen with the knob provided on the right side. The refractive index can be calculated from the scale one the upper side of sample. Take 2-3 readings for accurate results. Observed Refractive Index = 1.359, 1.36, 1.36 Page | 1 1.3 Calculations For 50 mol percent ethanol i.e. 50 mol percent water Molecular weight of ethanol is 46 g/mol Molecular weight of water is 18 g/mol Density of ethanol is 789 kg/m³ Density of water is 1000 kg/m³ ���(�) ∗ �(�) ∗ 100 ��(�) 50 = ���(�) ∗ �(�) ���(�) ∗ �(�) + ��(�) ��(�) 50 = 100 ���(�) + ��(�) + �(�) 1+ ���(�) + ��(�) + �(�) 1= ���(�) ∗ ��(�) ∗ �(�) ���(�) ∗ ��(�) ∗ �(�) ���(�) ��(�) ∗ �(�) = ���(�) ��(�) ∗ �(�) ���(�) 46 ∗ 1000 = ���(�) 18 ∗ 789 Since; ���(�) = 3.23898 ∗ ���(�) →���(�) + ���(�) = 100 → ���(�) = 100 − ���(�) 100 − ���(�) = 3.23898 ∗ ���(�) ���(�) = 23.59 & ���(�) = 76.41 Page | 2 2. Types of Trays (Plates) in Distillation The word tray and plate means the same thing. There are many types of trays and plates used in distillation column but the most common types are followings: • • • Bubble cap trays Valve trays Sieve trays 2.1 Bubble Cap Tray In this type of tray, there is a riser or chimney that is fitted on each and every hole of the tray and there is cap on the riser. The cap is placed on the holes in such a way that there is a space that allow the movement of vapors between hole and riser. The vapor that rises from the column is moved downward by the cap, bubbling in to the liquid on the bubble cap tray.This type of tray has more stable working and high flexibility than other types of trays. Figure 1: Bubble Cap Tray 2.2 Valve Tray In this type of tray, there are perforations that are covered by movable caps. The vapor produce in the column lift the caps of valve, self-providing the passage for vapor. The valve trays provides better mixing as compared to sieve tray because lifting caps in valve tray direct the flow of vapor into the liquid horizontally. There are number of fixed holes as in sieve trays but the difference is that there can be vent on the top of the holes that are fixed. The main advantage of this type is that it has low cost and does not easily foul. Page | 3 Figure 2: Valve Tray 2.3 Sieve Tray These type of trays are commonly used in the industry for distillation tray design. The main advantages of this type are • • • Simple Inexpensive High capacity In construction, it is perforated metal plate for vapors to pass. A weir contain the liquid level and downcomers that allow the liquid that overflows to the tray below the column. The feature of this type is its tray to tray dual flow arrangement. This type is very effective for large range of flows. The sieve tray also do not foul easily. Figure 3: Sieve Tray Page | 4 References M. J. LOCKETT, 1986, Distillation Tray Fundamentals, Cambridge University Press, London HENRY Z. KISTER, 1992, Distillation design, McGraw-Hill, New York Page | 5