University of Basra For Oil and Gas
Chemical and Refining Department
Name of student : kareem hassan
Number of student : (19)
Name of experiment : (( flooding ))
Number of experiment : ( 1 )
Date of experiment : 3 \ 12\ 2017
Group : ( B )
ABSTRACT
The Gas Absorption experiment was conducted in order to examine the air pressure drop
across the absorption column as a function of air flow rate with a different rates of water
flow. The result obtained is to be compared between theoretical values that has been
calculated. The experiment was run three times with different water flow rate which are
1.0 L/min, 2.0 L/min and 3.0 L/min. For every water flow rate, it was run for different air an
increasing pattern. The flooding point was recorded during the water flow rate of 3.0 L/min
and air flow rate of 80 L/min. The value of pressure drop taken was 14 mm H2O with 3 mm
H2O as compared in Appendix. Basically the pressure drop is increasing when the air flow
rate increased. The flooding happened when the air pressure from the bottom is too high
and pushed the water up. The percentage different between the pressure drop gained from
Appendix and the one recorded is 78.57%flow rate of 20 L/min, 40 L/min, 60 L/min, 80
L/min, 100 L/min, 120 L/min, 140 L/min, 160 L/min and 180 L/min. Graph of pressure drop
against the air flow rate was plotted and it showed
. INTRODUCTION
Absorption is a mass transfer process in which a vapor solute in a gas mixture is dissolved
into a liquid phase which the solute is more or less soluble. An example of absorption is
absorption of the solute ammonia from an air-ammonia mixture by water. Absorption, in
common with distillation, usually use special equipment for bringing gas and liquid phases
into intimate contact. The gas absorption unit in this experiment is meant to demonstrate
the absorption of air into water in a packed column. The gas and liquid normally flow
counter-currently, and the packing serve to provide the contacting and development of
interfacial surface through which mass transfer takes place. The gas absorption is also
designed to operate at atmospheric pressure in a continuous operation. A common
apparatus used in gas absorption and certain other operations is the packed tower. The
device consists of a tower, equipped with a gas inlet an distributing space at the bottom; a
liquid inlet and distributor at the top; gas and liquid outlet at the top and bottom,
respectively; and a supported mass of inert solid shapes, called tower packing. There are
many types of random packing available, for example Ceramic Ball saddle and the most
common is the . These packing are used to increase the surface area of contact between
the gas and the liquid absorbent .In a packed tower, there is a limit to the rate of gas flow
which is called as flooding velocity. The tower cannot operate if it exceeds this limit. At
loading point, which is the point in which the droplets of liquid are carried up with the gas
in packed column, the gas start to prevent the liquid from flowing down, and thus, pools of
liquid start to appear in the packing.
OBJECTIVE
To examine the air pressure drop across the column as a function of air flow rate for
different water flow rates through the column.
THEORY
In an absorption process, two immiscible phases (gas and liquid) are present in which the
solute will diffuse from one phase to the other through an interface between the two phases.
For a solute A to diffuse from the gas phase V into the liquid phase L, it must first pass
through phase V, the interface, and then into phase L in series. A concentration gradient has
to exist to allow the mass transfer to take place through resistances in each phase, as
illustrated below.
APPARATUS
The type of gas absorption unit used as figure below was SOLTEQ-QVF Gas Absorption
Unit with a glass type made of borosilicate 3.3 glasses with PTFE gaskets.
PROCEDURE
1. General start-up procedure of gas absorption unit was performed by laboratory
assistance.
2. Firstly, the valve V11 is opens slowly and adjusted to get the water flow rate of
around 1 L/min. Water are allowed to enter at the top of the column K1, and then flow
down the column and accumulated at the bottom until it overflows back into vessel
B1.
3. After that, valve V1 is open and adjusted to get an air flow rate of 20 L/min into
column K1.
4. After 2 minutes, the liquid and gas flow in column K1 is observed, and the pressur
drop across the column at dPT-201 is recorded.
5. Repeat step 3 and 4 with different values of air flow rate until the flooding in the
column K1 occurs while the water flow rate is maintained.
6. Step 2 to 5 was repeated with different values of water flow rate by adjusted the valve
V11.
DISCUSSION
In this experiment, the data was tabulated based on the necessary formula given. As shown
in
the calculation part, the pressure drop based on the equipment was stated. The following are
the graph showing the pattern on the pressure drop with different value of water flow rate;
1.0 l/m , 2.0 l/m and 3.0 l/m.
