done by: esraá hajjeyah supervised by: prof. m.fahim eng. yusuf ismail
TRANSCRIPT
Done byDone by::
Esraá HajjeyahEsraá Hajjeyah
Supervised bySupervised by::Prof. M.FahimProf. M.Fahim
Eng. Yusuf IsmailEng. Yusuf Ismail
OutlinesOutlines
• Distillation Column T-103.
• Refrigeration Cycle.
1.Distillation ColumnT-(103):
Objective: To separate propylene from propane and produce high purity of propylene as the desired product.
Assumptions
1-Tray spacing= 0.8 m2-Percent of flooding at maximum flow rate=85%3 -Percent of downcomer area of total area=12%
4 -The hole area =10% the active area.5-weir height=50 mm
6-Hole diameter=5 mm7-Plate thickness=5 mm
1. Collect the system physical properties.
Design procedure:
2 .Calculate liquid - vapor flow factor.
w vLV
w L
LF
V
WV = vapor mass flow rate, Kg/s
WL = liquid mass flow rate,
Kg/s
v = vapor density, Kg/m3
L = liquid density, Kg/m3
Select trial plate spacing from 0.15m to 1m. 3
2n (m )
v
VA
u
V = volumetric flow rate, m3/s
vu
= flooding at maximum flow rate, m/s
3 . (m /s)
3600
w
v
V M WtV
(m/s) %v fu flooding u
4. Calculate the net area required.
5. Calculate total column cross sectional area.
2 (m )1 %downcomer area of total area
nc
AA
6. Calculate the column diameter.
*4 (m) c
c
AD
7. Calculate number of holes.
2 (m ) %downcomer area of total area *d cA A
Where
dA = cross sectional area of downcomer , m2
n c dA A A Where
nA = net area, m2
2a c dA A A Where
aA = active area, m2
10%*h aA A
hA =hole area, m2
Area of one hole = 2*
4 hd
Where
Number of holes = Ah / area of one hole
8. Calculate height of the column.
(Plate spacing X actual number of trays)c cH D
9. Calculate thickness of the column.
Pr
0.6i
c cJ
t CSE P
Where
ct = column thickness, in
P = maximum pressure, psi
ri = column radius, in
= stress of metal, psi
JE = joint efficiency
S
10. Select the material of construction.
11. Select the material of insulation.
12. Estimate the cost of the equipment.
Results:
Type Tray column
Type of tray Sieve tray
Diameter (m) 6.43
Number of Trays 180
Tray Spacing (m)0.8
Number of Holes 125673
Height (m)158
Reflux Ratio 8.34
Material of Construction
Caron steel
Insulation Glass wool
Cost ($) 2,030,800
Discussion:
• From the original propylene process, the distillation column was simulated in hysys using 50 plates with propylene purity of 99.5%.
• At that number of plates two main problems were exists
1) The reflux rate was very high and this was affecting the diameter of the column.
2) Very high duty on the condenser
• To solve this problem I increased number of trays.
# of plates VS. diameter & height
0
2
4
6
8
10
12
14
0 20 40 60 80 100 120 140 160
# of plates
diam
eter
0
20
40
60
80
100
120
heig
ht
2.Refrigeration Cycle:
• Refrigeration is the process of removing heat from an enclosed space, or from a substance, and rejecting it elsewhere for the primary purpose of lowering the temperature of the enclosed space or substance and then maintaining that lower temperature.
• In the refrigeration cycle a substance, called the refrigerant, is compressed, cooled, and then expanded.
• A refrigerant is a compound used in a heat cycle. This fluid boils at a very low temperature enabling it to evaporate and absorb heat.
• Common industrial refrigerants are: -Ammonia -Propane -Ethane -Freon.
• These substances are used as refrigerants because of their very low boiling points at atmospheric pressure.
• There are many types of refrigeration cycles that used in industries. The single refrigeration cycle is the simple type. Improvements on the simple cycle are made to get lower temperatures.
HYSYS simulation for refrigeration Cycle
• In our plant the refrigeration cycle is needed to provide a very cold refrigerant as the utility stream for the condensers in the three distillation columns used in the propylene process.
Objective:
• From HYSYS, the temperatures of the outlet streams of these three condensers are negative, so to reach this low temperature we need to add refrigeration cycle section.
• The lowest temperature was reached using ethane at atmospheric pressure was -88.73°C.
Assumptions:
1) Simple cycle was simulated using ethane as the refrigerant.
2) Three streams of refrigerant were needed for each condenser.
3) Three evaporators were used and these evaporators are equivalent to the condensers of the distillation columns
4) Two flow sheets were designed for the refrigeration cycle . One with expander and the other one with valve.
Discussion:
Using a valve or an expander will produce the same required results for temperature of the refrigerant streams, so the only difference between the two flow sheets is in the cost of the equipments used.
A) For the first flow sheet using valve
Total cost = $ 353,600
B) For the second flow sheet using expander
Total cost = $ 1,288,800
Thank you for listening