1. Hydrocracking for Naphtha
Done by:-
Abdulaziz Al-Rashidi
Faisal Al-Azmi
Khalaf Al-Azmi
Mohammed Al-Azmi
Nawaf Al-Azmi
Supervised by:
Prof. Mohamed Fahim Eng. Yusuf Ismail

2. Outline: Introduction History World production and consumption Uses
Feedstocks and products
Reactions involved
Reactor’s design
Catalyst
Modes of operation
Process variables
Basic economy
Conclusion

3. Introduction:
The interest of using the hydrocracking has been caused by several factors:
High demand for gasoline, diesel, and jet fuel.
Hydrogen is available at low cost and in large amounts.
Environmental concerns limiting sulfur and aromatic compound concentration in motor fuels have increased.

4. Advantages of hydrocracking:
Better balance of gasoline and distillate production
Greater gasoline boiling-range naphtha yields
Improved gasoline pool octane quality and sensitivity
Production of relatively high amounts of isobutane in the butane fraction
Supplementing of fluid catalytic cracking to upgrade heavy cracking stocks, aromatics, cycle oils, and coker oils to gasoline, jet fuels, and diesel.
Improves combustion quality of product.

5. History:
Hydrocracking is one of the oldest hydrocarbon conversion processes.
Hydrocracking technology was developed in Germany between 1915 and 1945.
The first plant for hydrocracking of brown coal was in Germany in 1927.
In 1960s, the automobile industry was an important factor to develop hydrocracking processes.
The early 1970s saw a continuation of the rapid growth of hydrocracking in the United States.
Because of the increasing demand on hydrocracking products the process spread widely in the 1980s and early 1990s

6. World production and consumption

8. Uses of Naphtha: Feedstock for producing high octane gasoline.
Industrial solvents and cleaning fluids
In the home cleaning fluid
An oil painting medium
An ingredient in shoe polish
An ingredient in some lighter fluids
A fuel for portable stoves and lanterns
As a coating for elemental lithium metal, to prevent oxidation
As a fuel in gas turbine unit
As the working fluid in the naphtha engine.

9. Feedstocks and products.
Feed
Products
1. Kerosene
Naphtha
2. Straight –run diesel
Naphtha and / or jet fuel
3. Atmospheric gas oil
Naphtha, jet fuel and / or diesel
4. Vacuum gas oil
Naphtha, jet, diesel, lube oil
5. FCC LCO
6. FCC HCO
Naphtha and/or distillates
7. Coker LCGO
8. Coker HCGO

10. Reactions involved: Major routes of hydrocracking reactions:
1. Noncatalytic:
thermal cleavage of C-C bonds via hydrocarbon radicals, with hydrogen addition.
2. Monofunctional:
C-C bond cleavage with hydrogen addition over hydrogenation components consisting of metals (Pt, Pd, Ni), oxides, or sulfides.
3. Bifunctional
C-C bond cleavage with hydrogen addition over bifunctional catalysts consisting of a hydrogenation component dispersed on a porous, acidic support. In petroleum refining, most hydrocracking reactions follow this route.

11. In most hydrocracking processes, the feedstock is submitted to hydrotreating prior to hydrocracking, in the same or in different reactors.

12. Reactions occurring mostly during hydrotreating:
Hydrodesulfurization (HDS)
Hydrodeoxygenation (HDO)
Hydrodenitrogenation (HDN)
Olefin hydrogeneration
Partial aromatics hydrogenation

13. Reactions occurring mostly during hydrocracking:
Monoaromatics hydrogenetion convert the double bounds in benzene ring to single bound
Hydrodealkylation cracked the side chain of cycle compound
Hydrodecyclization Naphtha ring opening
Isomerization of paraffins Alteration of the arrangement of atoms in a molecule without changing the number of atoms C
300o C |
C – C – C – C C – C – C
Straight Chain AlCl Branched chain

15. Reactor’s design:
The reactors used in hydrocracking processes are downflow, fixed-bed catalytic reactors.
The reactors are normally carried out at average catalyst temperatures between 550 and 750°F (290 and 400°C) and at reactor pressures between 1200 and 2200 psig (8,275 and 15,200 kPa)

17. Modes of operation:
The hydrocracking processes are designed to upgrade a variety of petroleum feedstocks by adding hydrogen and cracking to a desired boiling range.
The feedstocks used in hydrocracking processes contain sulfur, nitrogen, and oxygen. These compounds have a negative effect on hydrocracking catalysts, and require hydrotreatment prior to contact with the hydrocracking catalyst. For that reason, most of the hydrocracking processes involve both hydrotreating and hydrocracking steps.
The processes used in hydrocracking can be divided into three major categories: single-stage, two-stage and once-through.

18. Single-Stage Recycle Hydrocracking:
The simplest configuration of hydrocracking process
It may contains single reactor or two reactors in series
It is used to maximize diesel products with amorphous catalyst
The reactor operates at temperatures varying from 300 to 450°C ( °F), and hydrogen pressures between 85 and 200 bar ( psig).
The effluent from the first reactor is not subjected to intermediate vapor/liquid separation and fractionation prior to being passed into the second reactor.
For feeds with relatively low endpoints, a single-stage recycle configuration is commonly used to achieve total conversion. However, such a configuration can be less selective for liquid product than a two-stage configuration because all conversion must be accomplished in a single stage.

20. once-through process
In the once-through process the unconverted oil resulting from the first pass is not recycled.
The fractionator bottoms are used as steam cracker feed, FCC feed, or lube oil base.
However, middle distillates made by this process are generally higher in aromatics and are therefore of poorer burning quality than those produced by recycle hydrocracking.
This process is carried out in low temperature and in low hydrogen partial pressure since the conversion of the heaviest molecules in the feedstock is not required
Lower capital cost
Catalyst deactivation is reduced by the elimination of the recycle stream

22. Two-Stage Recycle Hydrocracking:
A widely used hydrocracking process configuration is the two-stage process, which allows a larger throughput (higher feed rates) than the single-stage process.
It Contains three reactors:
First reactor is for hydrotreating
Second reactor is for partially hydrocracking
The Third reactor is used to totally hydrocrack (unconverted oil).
The conversion in R-1 and R-2 represents the first stage of the process, whereas the conversion in R-3 represents the second stage of the process
The first and second reactors in the two-stage configuration use the same catalysts as in single-stage configuration. The hydrocracking catalyst in the third reactor use either noble metal or base metal sulfide hydrocracking catalysts because of the absence of N and S. The base metal sulfide catalysts are most frequently used.
The hydrocracking in the second stage can be carried out at lower temperature than in the first stare due to the absence of ammonia in reaction environment. Thus, first-stage hydrocracking temperatures are in the range of °C ( °F), whereas second-stage hydrocracking temperatures are in the range of °C ( °F)

24. Comparison between process modes:
Mode of operation
Single-stage recycle
Two-stage
Once through
Advantages
Low capital investment
Used for feeds with low end points to achieve total conversion
More product yield flexibility
Use different catalyst each stage
Complete hydrogenation of the product with reduction in aromatics and increase smoke point
Lower temperature and lower hydrogen partial pressure
Longer catalyst life because of the absence of the recycle
Lower capital cost
Disadvantages
Less selective for liquid product
Used for low capacity plants
High capital investment
High severity
Less flexibility
Lower quality of products
High aromatic content

26. Product Qualities: Specification PRODUCTS Naphtha Jet fuel/kersone
H. Pour
Diesel
Fract.
Btms.
Gravity API
58.8
37.1
33.9 33
Sulfur
PPM / %wt 15 14
16.0
100
Nitrogen,
PPM
0.1
2.4
0.5
1.0
Dist. Range , Deg.
106 – 330
350 – 560
410 – 730
570 – 960
Flash Point , Deg. --
160
206
Smoke Point , MM 19
Pour Point , Deg 40 95
Freezing Point , Deg
( - ) 50

27. Catalyst

29. Spent catalyst:
All catalyst that cannot be used farther even after regeneration will be replaced and this type of catalyst is known as spent catalyst. The spent catalyst will be backed in drums and sealed in drums the catalyst will be send back to the supplier so that proper disposal can take place. The life time of the catalyst in our process is five years.

30. Regeneration of catalyst:
Regeneration of catalyst during normal operation of catalyst there will be deposition of coke on its surface. This coke deposition will block the active sites of the catalyst and thus the conversion will be reduced greatly. In order to make these sites active again the catalyst has to be regenerated. This usually done by burning of fuel gas or the surface of catalyst so that the carbon on the catalyst surface will be converted to CO2 and thus making the catalyst active again and bring back to its initial conditions. In our process the catalyst regenerated every three months.

31. Compared between amorphous and zeolite:
The advantages of zeolite are:
Greater acidity, resulting in greater cracking activity.
Better thermal/hydrothermal stability.
Better naphtha selectivity.
Better resistance to nitrogen and sulfur compounds.
Low coke-forming tendency.
Easy regenerability.

32. Process variables:
Process variables have a significant impact on the conversion, the yield and quality of the resulting products.
The primary reaction variables are reactor temperature and pressure, space velocity, hydrogen consumption, nitrogen content of the feed, and hydrogen sulfide content of the gases.

33. 1-Reactor Temperature: Reactor temperature is the primary means of conversion control. If the temperature of reactor increase the rate of reaction also increase. 2-Reactor Pressure: The primary effect of reactor pressure is in its effect on the partial pressures of hydrogen and ammonia. Conversion increases with increasing hydrogen partial pressure and decreases with increasing ammonia partial pressure. 3-Space Velocity: The space velocity varies directly with feed rate, As the feed rate increases the conversion decreases.

34. 4-Nitrogen Content: An increase in organic nitrogen content of the feed causes a decrease in conversion. 5-Hydrogen Sulfide: Hydrogen sulfide at low concentrations act as a catalyst to prevent the saturation of aromatic rings.

35. Storage tanks:
Tanks for a particular fluid are chosen according to the flash-point of that substance. The naphtha has medium flash point so it stored floating roof -tanks. These tanks are cone roof tanks with a floating roof inside which travels up and down along with the liquid level. This floating roof traps the vapor from fuels.

36. Basic economy
The price of naphtha vary with time depending on the market demand after some research the prices of the products were obtained through personal contact with KPC and the prices for September 2013 are:
Naphtha $/MT.
Diesel 120 $/Bbl.
Jet fuel 120 $/Bbl.

37. Basic economy

38. Basic economy

39. Conclusion
1- The hydrocracking process is used to convert heavy molecular weight to light molecular weight products.
2- The hydrocracking process include three modes of operation
Two stage.
Single stage once through.
Single stage recycle.
3- It consists of two main types of reactions which are hydrotreating reactions, and hydrocracking reactions.

40. THANKS!