Transcript
CHE 415 Unit Operations II Leader:
Professor: Data Reporter:
Group #2: Lab#3: Steam to water Inspector:
Objective:
The purpose of this experiment is to measure several characteristics of the column such as: Boil up rate, Entrainment, Maximum Overall Separation Efficiency, and Thermal Efficiency.
Task to be performed:
The group leader will run the experiment
The inspector will look at environmental and safety concerns during the experiment, use of the equipment in an industrial setting and making recommendations for improvement.
The data reporter will measure and record all data to perform calculations from the experiment.
Definitions:
Boil up rate: The boil up rate is the rate at which the vapor rises up the column.[2]
Capacity limitations due to entrainment: Entrainment is a design limitation in columns. Entrainment is caused by excessive carry-up of suspended droplets by rising vapor. [2]
Thermal efficiency of the column: will calculate from the heat added to the reboiler and the heat needed to produce the distillate. [2]
Bubble cap trays: Cross flow trays usually installed in rectifying columns handling liquids free of suspended solids. The bubble caps consist of circular cups inverted over small vapor pipes. The vapor from the tray below passes through the vapor pipes into the caps and curves downward to escape below the rim into the liquid. The rim of each cap is slotted or serrated to break up the escaping vapor into small bubbles, thereby increasing the surface area of the vapor as it passes through the liquid. [2]
Design method:
A feed mixture liquid enters the column at the feed tray on a specific height column for this experiment. The liquid trickles down past several separation stages, where the liquid comes into contact with vapor. The separation stages consist of bubble cap trays. The liquid stream flows down through the bottom section of the column. The product with the lowest boiling point is collected as bottoms, but part of the liquid is vaporized in a condenser, and re-enters the column. The condenser supplies the energy input to the system, required for separation. The vapor follows its way through the top section, called the Rectifying section, and enters a reflux drum. In the drum, the vapor is cooled down to liquid. Part of the product is returned to the column (called the reflux), and the remainder of the (high boiling point) product leaves the column as distillate.[1]
Consider a mixture of methanol (MeOH) and water (w) at an equilibrium stage inside the distillation column. A vapor stream (V) flows upward, contacting a downward flowing liquid stream (L). The concentrations of the liquid phase are given by Xw and XMeOH. The concentrations of the vapor phase are given by Yw and YMeOH.[1]
At the equilibrium stage, the methanol concentration in vapor phase is significantly higher than in the liquid phase. The vapor stream will have enriched methanol, and the vapor stream flows up and interacts with more liquid at the higher equilibrium stage. Therefore, the vapor stream leaving at the higher equilibrium stage will have even higher methanol concentration.[1]
List of Report task
Kenny – Theoretical background, technical procedure, reference.
Jason – Cover page, introduction, calculation, conclusion and recommendation, final report review.
Alex – calculation, results and discussion, conclusion and recommendation.
Reference:
http://everything2.com/index.pl?node=distillation
http://www.vendomecopper.com/obgloss.htm
