1. Petroleum and Gas Processing(TKK-2136)
16/17 Semester
Petroleum and Gas Processing(TKK-2136)
Instructor: Rama Oktavian
Office Hr.: M.10-15, Tu , W , Th , F

2. Outlines 1. Crude distillation unit: Desalter
2. Distillation column configuration
3. CDU material balance

3. Crude Distillation Unit (CDU)

4. Crude Distillation Unit (CDU)

5. Crude Distillation Unit (CDU)

6. Crude Distillation Unit
Crude desalter unit
Salt content crude oil is usually denoted as pounds salt (measured as NaCl) per thousand barrels of crude oil (ptb)

7. Crude Distillation Unit
Crude desalter unit

8. Crude Distillation Unit
Crude desalter unit
The salt content should be lowered to between 5.7 and 14.3 kg/1000 m3 (2 and 5 PTB)
Poor desalting has the following effects:
Salts deposit inside the tubes of furnaces and on the tube bundles of heat exchangers creating fouling, thus reducing the heat transfer efficiency
Corrosion of overhead equipment
The salts carried with the products act as catalyst poisons in catalytic cracking units

9. Crude Distillation Unit
Crude desalter unit operation variable
Desalting temperature – affect settling rate, typical desalting temperature can vary between 50 and150 C (122 and 302 F)
Washing water ratio – affect in salt removal, Kuwait crude (31.2 API) requires 7–8 vol% water addition relative to the crude rate
Water level - Raising the water level reduces the settling time for the water droplets in the crude oil, thus improving the desalting efficiency
Washing water injection point
Demulsifier injection rate
Type of washing water - relatively soft to prevent scaling, slightly acidic with a pH in the range of 6, free from hydrogen sulphide and ammonia
Pressure drop in the mixing valve - A pressure drop between 0.5 and 1.5 bar (7.4 and 22 psi) is used

10. Crude Distillation Unit
Crude electrostatic desalting unit

11. Crude Distillation Unit
Atmospheric distillation unit
Crude oil from the desalter is heated in a train of heat exchangers up to a temperature of 250°C–260°C and further by a tube-still heater (also known as a pipe-still furnace) to a temperature of 350°C–360°C
Top pressure is maintained at 1.2–1.5 atm
Vapours from the top of the column, consisting of hydrocarbon gases and naphtha, emerge at a temperature of 120°C–130°C
A few plates below the top plate, the kerosene fraction is drawn at a draw temperature of 190°C–200°C
A few plates below the kerosene draw plate, the diesel fraction ) is drawn at a temperature of 280°C–300°C
The temperature of the stream at the bottom reaches around 340°C–350°C

12. Crude Distillation Unit
Atmospheric distillation unit
A typical atmospheric distillation column contains 41 plates
The hot feed crude oil is flashed in the fifth plate
Products:
top distillate (IBP–140°C cut)
straight run kerosene (140°C–270°C cut)
straight run diesel (270°C–340°C cut)
JBO (340°C–365°C cut)
the bottom residue (RCO, 365°C +cut)

13. Crude Distillation Unit
Atmospheric distillation unit

14. Crude Distillation Unit
Atmospheric distillation unit

15. Crude Distillation Unit
Product stabilization

16. Crude Distillation Unit
Condition parameter
Column Pressure
Controlled by the back pressure of the overhead reflux drum
The top tray pressure is 0.4–0.7 bar gauge (6–10 psig) higher than the reflux drum
The flash zone pressure is usually 0.34–0.54 bar (5–8 psi) higher than the top tray
Overhead Temperature
must be controlled to be 14–17 C (25–31 F) higher than the dew point temperature for the water to prevent water liquid condensation

17. Crude Distillation Unit
Condition parameter

18. Crude Distillation Unit
Crude material balance
Crude Assay Data

19. Crude Distillation Unit
Crude material balance
Crude Assay Data
PROPERTIES OF TBP CUTS
Cuts
Yield
Den 15°C S
RSH
RON
MON
Napht.
Aro.
RVP
LIGHT °C
wt%
vol %
kg/m3
mg/kg
clear
vol%
kPa
NAPHTHA
15-65
3.52
4.52
644
0.0032
86.2
81.5
4.6
0.1
185.28
15-80
5.29
6.62
661
0.0037 1
86.1
81.2
9.9
0.3
150.93
HEAVY
80-150
16.41
18.03
752
0.0081 2
32.2
11.3
80-175
22.45
24.29
764
0.0103
32.0
13.3
12.35
13.38
763
0.0090
32.9
14.5
Smoke
Acidity
Cetane
Freez. Pt
Visc cSt
Flash
KEROSENE
Pt mm
mgKOH/g
Index
50°C
Point
21.72
22.08
813
0.029 16
0.08
35.6
-54
16.2
1.0 -
15.68
15.82
820
0.033
0.09
36.9
-50
15.1
1.2
27.87
28.16
818
0.034
37.9
-49
Anilin
Cloud Pt
CFPP
Pour Pt
UOPK
GASOIL
Point °C C
100°C
55.55
53.75
854
0.072 64
45.3 -6 -9
-12
2.5
11.7
39.86
37.93
869
0.088 68
48.1 -1 -2
3.6
1.5
34.31
32.90
862
0.083 67
48.4 -7 -8
3.1
1.4
Conrad. Ni Va
Total N
Bas N
Asp C7
VACUUM
150°C
wt %
DISTILLATE
17.84
15.73
937
0.15
0.5 80
0.027
102 41
6.1
11.6
18.53
16.31
939
0.8
0.031
110
6.6
2.7
19.09
16.77
941
0.16
0.041
117 42
7.0
2.8
0.2
13.54
11.74
953
0.18
1.7 81
0.052
152 47
10.1
3.7
Pene
RESIDUE
mm/10
> 375
20.77
18.11
948
0.17
4.2
0.179 34 9 3
587000
0.4
> 550
2.93
2.38
1020
0.32
26.5 5 15
1.100 48 74
199
2.0
> 565
2.24
1.80
1028
0.34
31.8 6 19
1.400 51
2470
145
124
2.4
> 580
1.68
1.34
1036
0.36
37.6 8 23
1.750 55
8420
321 91
This crude oil data sheet is for information purposes only. No guaranty is given as to its accuracy or as to any consequences arising from its use.
TOTAL DTS / AM
Mar-14

20. Crude Distillation Unit
Material balance

21. Crude Distillation Unit
Solution
Step 1: Construct fifth order polynomial fit of TBP data versus vol%

22. Crude Distillation Unit
Solution
Step 2: From the end point of each cut, calculate the cumulative volume percent, example: the cumulative volume percent for the off gas and the light straight run naphtha is 1.33 and 8.6%, respectively

23. Crude Distillation Unit
Solution
Step 3: Calculating average normal boiling point. The average normal boiling point for each cut is calculated at the mid percent of each cut.
in this case the light straight run naphtha is /2 or 4.965%
Average boiling point - to be 43.6 C

24. Crude Distillation Unit
Solution
Step 4: Calculating Molecular weight.

25. Crude Distillation Unit
Solution
Step 5: Calculating specific gravity.

26. Crude Distillation Unit
Solution

27. Crude Distillation Unit
Material balance

28. Vacuum Distillation Unit
Products
Light vacuum gas oil (LVGO)
Medium vacuum gas oil (MVGO)
Heavy vacuum gas oil (HVGO)
Vacuum residue

29. Vacuum Distillation Unit
Process overview