differences between commercial reforming processes ......naphtha catalytic reforming...
TRANSCRIPT
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Catalytic Reforming Processes
17
Differences between commercial
reforming processes
Catalyst regeneration procedure
Catalyst type
Conformation of the equipment
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Process classification
18
This classification is based on the frequency and mode of
regeneration.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Naphtha Reforming Processes
19
Table 1. Summary of Naphtha Reforming Processes
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
20Figure 5. Semi-regenerative (SR) fixed bed reforming process
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
21
The name semi-regenerative comes from
regeneration of the catalyst in the fixed bed
reactors after shut down by burning off the
carbon formed on the catalyst surface.
Reactions such as dehydrogenation of
paraffins and naphthenes which are very
rapid and highly endothermic occur in the
first reactor, with high temperature drop.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
22
Reactions that are considered rapid, such as
paraffin isomerization and naphthens
dehydroisomerization, give moderate
temperature decline in the second reactor.
Furthermore, slow reactions such as
dehydrocyclization and hydrocracking give
low temperature decline in the third reactor.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
23
The temperature and
concentration profile
in each reactor.
Figure 6.
(A) Furnace and reactor layout for fixed
bed reformer
(B) Variation of temperature in the
reactors
(C) Variation in effluent compositions;
Po is initial paraffins
No is initial napthenes
Ao is intial aromatics
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
24
To prevent catalyst coking, the hydrogen
partial pressure is maintained at a level such
that the hydrogen-to-hydrocarbon ratio by
weight (H2/HC) is 4-6.
This is done by recycling some of the
hydrogen produced.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
25
Some light hydrocarbons (C1–C4) are separated
from the reformate in the stabilizer.
At the top of the stabilizer residual hydrogen and
C1 to C4 are withdrawn as condenser products,
which are then sent to gas processing, and part
of the liquid product (C3 and C4) is returned from
the reflux drum back to the stabilizer.
The main product of the column is stabilized
reformate, which is sent to the gasoline
blending plant.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Semi-regenerative Process
26
A slight modification to the semi-regenerative
process is to add an extra-reactor to avoid
shutting down the whole unit during
regeneration.
Three reactors can be running while the forth
is being regenerated.
This modified process is called the ‘‘cyclic
fixed bed’’ process.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Continuous Regenerative (moving bed) Process
27Figure 7. Continuous regenerative reformer (CCR), UOP Platforming process
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Continuous Regenerative (moving bed) Process
28
The effluent from each reactor is sent to a
common furnace for heating.
The catalyst moves downwards by gravity
from the first reactor (R1) to the forth reactor
(R4).
The catalyst is sent to the regenerator to
burn off the coke and then sent back to the
first reactor R1.
The final product from R4 is sent to the
stabilizer and gas recovery section.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Continuous Regenerative (moving bed) Process
29
The process can be operated at lower
hydrogen partial pressure (PH2 = 3 bar)
compared to the semi-generative process
(PH2 = 35 bar), with a reformate yield gain of
nearly 10 vol %.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Catalytic Reforming Processes
30
Table 2. Typical operating conditions of three reforming processes
re
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Comprehension questions
1. What is the role of the reformer in the refinery?
2. What groups of hydrocarbons have the highest octane
numbers?
3. What groups of hydrocarbons have the lowest octane
numbers?
4. How does the number of carbon atoms in the chain of
molecule influence the octane number of paraffins, iso-
paraffins, naphthenes / aromatics?
5. List the types of reforming reactions and show their
relative importance.
31
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Comprehension questions
32
6. List the types of reforming reactions and show their
relative importance.
7. What two types of coke form in the catalytic reforming?
8. Why the feed of catalytic reforming is heated before
entering the reactors?
9. List the promoters for reforming catalyst which are
added to improve properties of the catalyst.
10.List the impurities for the reforming catalyst.
PROFESSIONAL COURSE IN ENGLISH
“FUNDAMENTALS OF PETROLEUM REFINING”
Unit 8. Naphtha Catalytic Reforming
Comprehension questions
33
12.What are the main pieces of equipment in the reforming
process?
13.What modes of reforming process operation exist
according to the catalyst regeneration procedure?
14.What types of catalyst bed do you know?
15.What reforming reactions occur in the first, second and
last reactor?
16. In your opinion, will the reforming play the same role of
the major process for gasoline components production
in the future?