填料塔气体吸收实验 实验报告 英文.doc

Division of Engineering
Assessed Report
Department of Chemical Engineering
EH1SPF: Gas Absorption in a packed columntilised in the packed tower, and CO2 is considered as the target gas which should be absorbed. Water is used as solvent liquid to solute CO2. By measuring the inlet and the outlet concentration, CO2 absorbed can be determined.
Background theory
The measure of the efficiency of the absorption process can be expressed in the terms of overall height of liquid film transfer unit, HOL. The smaller the HOL is, the more efficient the absorption process will be. The height of the column (m) Z is defined as:
z=0zdZ=LKxax2x1dxx-x*=
Where,
L
kmol/()
the molar flow rate of liquid per unit cross sectional area
Kxa
kmol/()
overall liquid transfer coefficient
NOL
dimensionless
the number of transfer units based on overall liquid film coefficient
HOL
m
the height of a transfer unit based on overall liquid film coefficient
KXA is a variable which can indicate the efficiency of gas absorption.
As KXA=L/ HOL, it can be determined that the larger KXA value, the better efficiency of the system.
And the absorption factor is defined as:
A=L/mG
Where,
A
absorption factor
L
molar flow rate of liquid
G
molar flow rate of gas
m
slope of the equilibrium line on a mole fraction basis
The balance equation is yA=mxA
Where m=E/P
E is the henry’s constant, E=f(t)
P is the total pressure
xA is the molar fraction of the contaminant in the gas phase at equilibrium.
yA is the molar fraction of the contaminant dissolved in the liquid phase at equilibrium
After A is given, the following equation can be used to determine the number of transfer units based on overall liquid film coefficient (NOL):
NOL=11-Aln1-Ay1-mx2y1-mx1+A
Where,
A
absorption factor
x1
CO2 concentration in the inlet gas
x2
CO2 concentration in the outlet liquid
y1
CO2 concentration in the inlet liquid
Follow steps need to be done in this ex