1- Crude from storage (feed to desalter) :
Density: to calculate the crude API
API , degree = 141.5 / Specific gravity at 15.6/15.6 c - 131.5
Design API = 30 - 32 degree
Salt content < 50 PTB
BS&W D4007 by centrifuge method not give the accurate results for water and sediment
sediment and water leads to corrosion and fouling in heat exchangers
water leads to fractionation tower upset.
water content by karl fischer ASTM D4928 is the accurate method for water & ASTM D473 for sediment .
Sulphur content D4294 to estimate the quantity of the acid gas and then the quantity of sulfur product and affect in the sulfur of feed unit 08 and increase the peak temperature .
2- Crude from desalter, ( desalter B outlet )
Salt outlet consent to measure the desalter efficiency , 1PTB maximum
1PTB = 2.86 ppm
Desalter efficiency = Salt inlet - Salt outlet X100
Salt inlet
PTB = Ib / 1000 bbl
Water content < 0.5 % mass
3- Naphtha, ( 40 - 180°C )
Density D 4052 : for quantity and for contamination from other products
Color D 156 : for contamination from other products
Distillation D86
IBP : to measure the efficiency of separation between naphtha and LPG in the debutanizer and its effect on the vapor pressure of naphtha.
5% : to measure the efficiency of separation between products in the fractionating tower
95% : to measure the efficiency of separation between products in the fractionating tower
Gap = 10 - 20°C & 95% = 160-165°C
If the 5% of heavy product ( kerosene ) - 95 % of light product ( naphtha ) = + ve reading ( 10 °C min )
That means there is a gap between product and good separation
If the 5% of heavy product ( kerosene ) - 95 % of light product ( naphtha ) = - ve reading
That means there is a overlap between product and bad separation
Vapor pressure D 5191 :to measure the efficiency of separation between naphtha and LPG in the debutanizer.
High VP of naphtha , means LPG is dropped in naphtha , high 5% residue in LPG , means it contains C5+ naphtha .
4-kerosene ( 170- 240°C )
Density D 4052 : for quantity and for contamination from other products
Color D 156 : for contamination from crude heat exchanger
Distillation D86
IBP : its effect on the flash point of kerosene
5% : to measure the efficiency of separation between products in the fractionating tower
95% : to measure the efficiency of separation between products in the fractionating tower
95 % & End point effects on the freezing point
Gap = 10 - 20°C & 95% = 225 - 230°C
If the 5% of heavy product ( diesel ) - 95 % of light product (kerosene ) = + ve reading ( 5 °C min )
That means there is a gap between product and good separation
If the 5% of heavy product ( diesel) - 95 % of light product ( naphtha ) = - ve reading
That means there is a overlap between product and bad separation
Flash point D 56 : For safety during storage and transportation , 40°C minimum.
Freezing point D 7153: for fluidity and affected by the 95 % &EP , -47°C maximum
Total acidity D3242
RSH , UOP 163
To measure the feed quality of kerosene merox 06-sc-01
5 - L -Diesel (200- 280°C )
Density D 4052 : for quantity and for contamination from other products
Color D 1500: for contamination from other products
Distillation D86
IBP : its effect on the flash point of diesel
5% : to measure the efficiency of separation between products in the fractionating tower
95% : to measure the efficiency of separation between products in the fractionating tower
95 % & End point effects on the pour point
Recovered at 350°C , 85 % minimum , volatile HC for good atomization for fuel engine
Flash point D93: For safety during storage and transportation , 60°C minimum , affected by IBP & 5% recovered.
Pour point D 97 , 0°C maximum for transportation during pipe lines and for engine start up during cold weather, according to scheduling daily guidelines .
6 - Sour LPG
Composition from C 1 to C 5 , D2163
95 % evaporated or 5 % residue , D 1837 : to measure the efficiency of separation between naphtha and LPG in the debutanizer , as per EGPC spec.
7 - H-Diesel
sent to Cold feed unit 08 tk 11 , 40 , 41
Density D 1298 by hydrometer at 60°C
Color D 1500 : for contamination from fuel oil .
Distillation D1160 :to measure the efficiency of separation between products in the fractionating tower
8 - Atmospheric bottom
Density D 1298 by hydrometer at 60°C
Distillation D1160 :
IBP = 270 °C
50% = 550°C
Kinematic viscosity D 445 at 100 °C and converted to RedWood viscosity
All above tests for feed quality to vacuum tower
9 - LVGO ( 250 - 500°C )
Density D 1298 by hydrometer at 60°C
Color D 1500 : For contamination from other products.
Distillation D1160 :to measure the efficiency of separation between products in the Vacuum tower
10 - HVGO ( 350 - 550°C )
Density D 1298 by hydrometer at 60°C
Color D 1500 : For contamination from other products.
Distillation D1160 : Feed quality of Hydrocracking process
Sulfur D 4294 : Feed quality and effects on process parameters in Hydrocracking process .
Carbon residue D 4530 : Deactivate the hydrocracker catalyst , 0.4 %mass maximum ,
To decrease the CR in HVGO , you must increase the reflux ( wash oil ) .
Reflux : returning some condensed product.
Asphaltene , UOP 614 : Deactivate the hydrocracker catalyst unit 08 , 0.05 % mass maximum
11 - VR ( 450 - 550°C at 10 % )
Density D 1298 by hydrometer at 140°C
Distillation D1160 : Feed quality of unit 11
Carbon residue D 4530 : Feed quality of unit 11 to estimate the coke production.
Flash point > 130 °C
12 - Steam Blowdown
To measure the boiler efficiency and no chloride and no hardness
PH D 1293 = 10 -10.5
conductivity , D1125
Hardness D1126 , nil
chloride APHA 4500cl D , nil
Phosphate APHA 4500 P C ( 5 -10 ppm ) or according to chemical program
13 - Sour water ( Fract.)
Accumulating vessel for sour water from fractionating tower to evaluate the performance of chemical injection in the overhead section to prevent corrosion
PH = 5.5 -6.5 , Adjusted by neutralizing amine injection
Chloride < 20 ppm, Adjusted by NaOH injection in the crude after desalter
Total Iron D 1068 < 1 ppm, Adjusted by corrosion inhibitor injection
14- Sour water ( Vacc. )
Accumulating vessel for sour water from vacuum tower to evaluate the performance of chemical injection in the overhead section to prevent corrosion
PH = 5.5 -6.5 , Adjusted by neutralizing amine injection
Chloride < 20 ppm, Adjusted by NaOH injection in the crude after desalter
Total Iron D 1068 < 1 ppm, Adjusted by corrosion inhibitor injection
If the salt content in the desalter outlet is high the chloride in the accumulator & sour water will be high .
15 - Desalter inlet
From stripped water unit 15 train - 1 or service water
PH > 8.5 To avoid formation of sodium naphthenate ( surfactants ) hard to break, resist the crude oil and water separation in the desalter .
Chloride , nil
NH3 D1426 < 50 ppm
H2S UOP 683 < 10 ppm
16 - Desalter outlet
sent it to the wastewater treatment plant
PH > 5.5 , adjusted by caustic soda injection Oil content D 7066 , 200 ppm maximum , to evaluate the desalter efficiency and good separation between oil and water
Demulsifier is used to decrease the oil content in the desalter outlet .
COD D1252 B , 400 ppm maximum
Chloride content , related to salt content in the crude
17 - Caustic UOP 210
Inlet 10 %
Outlet 3-5 %
Used for reduction of chloride ( < 20 ppm ) in overhead and PH adjusting for desalter outlet.
Normal operation of CDU requires caustic soda solution injection in the crude feed line after desalter to control HCl in the column’s overhead to mitigate acid corrosion
dilution 3 - 5 % , > 5 % leading to corrosion and caustic stress cracking CSCC , HIGH sodium content in VR ( MAX 25 PPM ) leading to high tendency of foam in Delayed coker unit ,
requiring injection of anti foam resulted in high silicone content in coker products that poisoning catalyst in the downstream process Naphtha Treatment , Reformate , Isomerization , Diesel Treatment , Hydrocracking
Low concentration of caustic enhances good dispersion into the crude oil as well as better control of caustic addition
Caustic not only reacts with the HCl , Mg Cl2 , CaCl2 but it also reacts with any other acids species in the system such as H2S , organic acids , naphthenic acids , CO2 , SO- based acids and phenolic compounds The presence of these other species reduces the efficiency of chloride reduction .
18 - Debutanizer off gas
Its low pressure and mixed with the fuel gas and sent to LPG Recovery for H2S removal , this discus from where you get it H2 in CDU
Composition by UOP 539 , mainly HC , H2 , H2S & CO2 & N2
19 - Vacuum - off gas / low pressure sample
Composition by UOP 539 , mainly HC ,Olefins , H2, N2 ,O2 , CO, CO2 & H2S
Olefin's content , 10 % maximum , indicates if there is thermal cracking in the vacuum tower.
N2 Content , if there is any leak in the vacuum tower
H2 content coming from fuel gas system
