In this PPT we have try to explain how Delayed Coking process works and how we can apply Heat exchanger network synthesis to reduce Utility Cost.

1. SAL ENGINEERING AND TECHNICAL INSTITUTE
TOPIC : HEAT EXCHANGER NETWORK SYNTHESIS
FOR DELAYED COKER UNIT
Bachelor of engineering
In
Chemical engineering
Semester 7th
User Defined Project(UDP)
ACADAMIC YEAR 2020-21

2. SUBMITTED BY :
SR NO NAME ENROLLMENT NUMBER
1 GARUD RAJ 171260105016
2 DEVMURARI PRIYANK 171260105013
3 PANDYA DHAIRYA 171260105019
Internal guide:-
PROF. KINJAL PATEL
ASSISTANT PROFESSOR
DEPARTMENT OF CHEMICAL ENGINEERING
SAL ENGINEERING & TECHNICAL INSTITUTE
AHMEDABAD

3. CONTENT :
 Introduction
 Problem statement
 Process description
 Heat integration by designing heat exchanger network by using
pinch analysis method
 Snap shot of GCC curve in aspen energy analyzer
 Snap shot of composite curves from aspen energy analyzer
 Snap shot of results from aspen energy analyzer
 References

4. INTRODUCTION
 A heat exchanger network obtained using the pinch design
method is a network where no heat is transferred from a hot
stream whose temperature is above the pinch to a cold stream
whose temperature is below the pinch.
 Heat exchangers are widely used in industry both for cooling
and heating large scale industrial processes . In many industrial
processes there is waste of energy or a heat stream that is being
exhausted, heat exchangers can be used to recover this heat and
put it to use by heating a different stream in the process.
 In our process which is a delayed coking process where
requirement of heating and cooling utility is very high , so we can
apply heat exchanger network synthesis for this process so, we
can reduce the utility demand as this demands reduce ultimately
the cost for the process also reduces .

5.  In our process which is a delayed coking process where
requirement of heating and cooling utility is very high ,
so we can apply heat exchanger network synthesis for
this process so, we can reduce the utility demand as this
demands reduce ultimately the cost for the process also
reduces.
 In this we will apply pinch analysis method to design
heat exchanger network by using data from literatures .
INTRODUCTION cont. ……

6.  For this we will proceeding step by step like first we find the minimum
hot and cold utility required for the process by using methods like
temperature interval method or linear programming method and etc. from
these methods we will find pinch point which shows how many stream
would be at below pinch and how many stream are at above pinch Then
we will proceed for the heat exchanger network with CP and Hot and
Cold stream criteria for above and below pinch
 Based on pinch design method, two sub-cases of revamp study have been
considered namely (a) installation of new heat exchangers for the entire
network and (b) reutilization of existing heat exchangers. Based on the
study, it has been evaluated that the revamp design of existing CDU HEN
without considering the DCU free hot streams allows the enhancement of
heat integration by 4.73% with respect to that available for the base case.
INTRODUCTION cont. ……

7. PROBLEM STATEMENT:
 DESIGN HEAT EXCHANGER NETWORK
FOR DELAYED COKER UNIT .

8.  In delayed coking process we can separate or in other words
we can distillate the vacuum residual oil
 In the delayed coking plant, the raw material is the vacuum
residual oil from Crude Oil Unit, and the products contains
wet gas, gasoline, diesel oil, wax oil and petroleum coke.
 Delayed coking process is divided into two parts
1)Fractionation of vacuum residual oil
2)Production of coke .
PROCESS DESCRIPTION

10. Fractionation of vacuum residual oil
 The feed enters in the feedstock Buffer tank through the heat
exchanger(E101) where it is preheated.
 Now this preheated feed enters in the fractionating column
where the separation takes place.
 Due to having low boiling point the feed containing naphtha
goes out from top of column where it is cooled to 40 ℃ by
air cooler(A115) and cooler(E116).
 Now the mixture enters the gas-liquid separation drum where
wet gas is separated and naphtha is recovered.

11.  The top recycled reflux of the fractionating column divides into
two parts. One part returns to the fractionating column as
internal reflux, and the other part returns to the fractionating
column after cooled to 112℃ via an air cooler (A120).
 The diesel oil divides into two parts. One part goes returns to the
fractionating column as reflux.
 The other part is again divided into two parts after exchanging
heat with the raw material (E101). One part returns to the
column as the diesel oil reflux.
Fractionation of vacuum residual oil cont.…

12.  The other part divides into two parts once more after cooled in the steam generator
(E108) and the diesel air cooler (A119). One part goes to the gas desulfurization
system as absorbent after cooled to 40℃ in a cooler (E118), and the other part leaves
the plant.
 The medium reflux returns to the column via bottom reboiler of gas desulfurizing
underorder(E505), feedstock -medium reflux heat exchanger(E102).
 The heavy wax oil divides into two parts. One part goes back to the fractionating
column as internal reflux. The other part divides into two parts again after
exchanges heat with the raw material (E104) and in the bottom reboiler of gas
desulfurizing unit stabilizer (E509). One part returns to the fractionating column as
the heavy wax oil reflux, and the other part divides into two parts once more after
cooled to 90 ℃ via a steam generator (E110) and the heavy wax oil cooler
(E114A,B). One part mixes with oil-gas from the coke column as quench oil, and
the other part leaves the plant after mixed with the light wax oil.
Fractionation of vacuum residual oil cont.…

14. The recycled oil from the bottom of the fractionating column is
divides into two parts.
 One part returns to the feeding line and mixes with the raw
material, and the other part returns to the bottom of the
fractionating column after exchanges heat with the raw material
(E105).
The raw material at about 163℃ is heated by diesel oil and reflux
(E101), medium reflux (E102), light wax oil (E103), heavy wax
oil and reflux (E104), and recycled oil and reflux (E105) to
294℃, then combines with the recycled oil from the bottom of
fractionating column to go to a furnace to about 500℃, and
finally gets into the bottom of a coke column.
2 ) COKE PRODUCTION

15. Through cracking and condensation reactions in the coke
column, oil-gas and petroleum coke are generated.
The hot oil-gas from the top of the coke column is
fractionated into wet gas, crude gasoline, crude diesel oil,
and crude wax oil through a fractionation column.
The petroleum coke is decoked through hydraulic method
and then sent outside the plant.
2 ) COKE PRODUCTION CONT ….

16. Heat integration by designing heat exchanger
network by using pinch analysis method:
 Pinch analysis provides techniques for heat integration to design
the heat exchanger network (HEN), not only for grassroots
design but also to retrofit an existing system and optimize the
process.
 Systematic and general methods for designing integrated
production systems ranging from individual process to total
sites and with special emphasis on efficient use of energy and
reducing environmental impact .
 Heat integration deals with heat recovery in group of
opportunity termed as process

17. STREAM
NO.
STREAM FLOWRATE
TON/HOUR
T INLET
CELCIUS
T OULET
CELCIUS
HEAT DUTY
kW
C1 Raw material 1908 163 500 58083
C2 Recycled oil 38 365 500 9849
H1 Recycled oil to
the column
90 388 310 5691
H2 Heavy wax oil I 54 371 208 6513
H3 Heavy wax oil II 18 230 150 2270
H4 Light wax oil 30 348 80 4624
H5 Medium reflux 74 315 219 4831
H6 Diesel oil and
reflux
215 235 172 7949
H7 75 172 43 6367
H8 Diesel absorbent 15 43 83 6031
H9 Reflux at top of
the fractionator
160 142 83 6031
H10 Oil gas at top of
the fractionator
45 111 36 4001
STREAM DATA

18. DATA ENTRY FROM LIERATURE:

19. COMPOSITE CURVE

20. GCC CURVE

21. RESULTS

22.  Taking delta t minimum = 10 ℃
 Hot Pinch temperature is 235℃
 Cold Pinch temperature is 235℃
 Minimum hot utility required is 40.15 Mw
 Minimum cold utility required is 20 Mw
 Where actual hot and cold utilities are 48.764.9 Mw and
29.745 Mw
 Our next step is to construct heat exchanger network by
pinch analysis method , we will work on it .
RESULTS:

23. REFRENCES
1)Heat integration of delayed coking plant by Yanping Li, Xu Wang, Xiao Feng
Department of Chemical Engineering Xi’an Jiaotong University Xi’an, China published on 2009
2) Vijaya Kumar Bulasara , Ram Gopal Uppaluri , Aloke Kumar Ghosal, Revamp study of
crude distillation unit heat exchanger, department of chemical engineering IIT Guwahati,
India(2008)