brahmaputra cracker & polymer limited quality …...temperature drop of oxidized caustic/vapor...
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BRAHMAPUTRA CRACKER & POLYMER LIMITED
Quality Circle Project
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
Project Title: Performance restoration of WAO Process Cooler of Ethylene Cracker Unit of BCPL, Lepetkata.
(Project registration no. : BCPL/LEP/MECH/ECU/QC/03 dated 15/02/2019)
Quality Circle Project by
Team Leader : Mr. Ranabir Tarat Team Members :
Md. Kalamuddin
Mr. Nabajit Das
Mr. Nitul Kalita
Mr. Pankaj Kumar
Mrs. Niharika Kakati
Mr. Angshuman Gogoi
Mr. Chandan Dowari
Mr. Polakh Protim Boruah
Champion : Mr. Pranjal Kakoty
HOD : Mr. R.P.Singh
BRAHMAPUTRA CRACKER & POLYMER LIMITED
QUALITY CIRCLE PROJECT REGISTRATION
WORK CENTER: BCPL As on: 15/02/2019
(Pranjal Kakoty) (R. P. Singh) (R. P. Singh)
Team Leader Champion HOD
1. Project Registration No.
(To be given by QC Coordinator*)
BCPL/LEP/MECH/ECU/QC/03
2. QC Team Name Explorer
3. a. Team Leader Mr. Ranabir Tarat
b. Team Members Md. Kalamuddin
Mr. Nabajit Das
Mr. Nitul Kalita
Mr. Pankaj Kumar
Mrs. Niharika Kakati
Mr. Angshuman Gogoi
Mr. Chandan Dowari
Mr. Polakh Protim Boruah
4. Champion Mr Pranjal Kakoty
5. HOD Mr R.P.Singh
6. Project Title
(Should be Specific, Measurable, Achievable,
Realistic, Time Bound)
Performance restoration of WAO Process Cooler of
Ethylene Cracker Unit (ECU) of BCPL, Lepetkata.
7. Potential Benefits:
Tangible
1. By performance restoration of WAO process cooler,
erosion of waste water piping and machineries can be
minimized.
2. Cost benefit by reducing maintenance cost.
8. Target Completion Date
(Plan the activities in milestone chart below)
15/02/2019.
Milestone Chart
No. Activity week
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Targ
et
1. Defining the
problem
2. Analyzing the
problem
3. Identifying the causes
4. Finding out the root
causes
5. Data Analysis
6. Developing solution
7. Foreseeing possible
resistance
8. Trial implementation and
checking
performance
9. Regular implementation
10. Follow up/Review
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
1. Project Registration No.:
(To be given by QC Coordinator*)
BCPL/LEPK/MECH/ECU/QC/2018-19/03
2. QC Team Name: Explorer
3. a. Team Leader: Mr. Ranabir Tarat
b. Team Members: Md. Kalamuddin
Mr. Nabajit Das
Mr. Nitul Kalita
Mr. Pankaj Kumar
Mrs. Niharika Kakati
Mr. Angshuman Gogoi
Mr. Chandan Dowari
Mr. Polakh Protim Boruah
4. Champion/HOD: Mr. Pranjal Kakoty / Mr. R. P. Singh
5.
Improvement Project:
Project Title:
Performance restoration of WAO Process Cooler of
Ethylene Cracker Unit (ECU) of BCPL, Lepetkata.
Introduction:
The purpose of the Wet Air Oxidation System is to reduce
the concentration of sulfides (to less than 1 mg/l)
contained in the spent caustic. It converts sodium sulfide
in the pretreated spent caustic to sodium sulfate. The
effluent from the Wet Air Oxidation (WAO) System is
then neutralized by sulfuric acid and routed to waste water
treatment plant for blending with other effluent streams.
WAO feed pump (116-PA-801A/B) receives spent caustic
from the spent caustic storage tank and raises its pressure.
The high pressure air from one of the WAO Air
Compressor (116-KA-801A/B) is combined with the
above liquid feed just before entering to WAO
feed/effluent heat exchanger (116-EE-801). Then the
mixture enters the WAO Reactor (116-RB-801) where the
chemical oxidation reactions occur that will cause an
increase in temperature. Operating pressure in the reactor
is approximately 28 kg/cm2g. The temperature of the
reactor is controlled by adding de-superheated steam. The
steam flow is then sent through a sparger pipe into the
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
WAO Reactor. The hot oxidized reactor discharge
products are directed to the shell side of 116-EE-801
where heat is transferred to the cold feed of reactor
entering the exchanger.
Upon exiting the shell side of 116-EE-801, the oxidized
spent caustic and vapor is passed through the tubes of the
WAO Process Cooler (116-EE-802). Cooling water is
used on the shell side to cool the reactor discharge
products to approximately 50°C.
The oxidized caustic/vapor mixture leaving 116-EE-802 is
de-pressurized to approximately 7 kg/cm2g through one
of two pneumatically operated pressure control valves
which discharge into the WAO Separator (116-VV-801),
where liquid/vapor phases of the reactor discharge
products separate into their respective phases. The
oxidized spent caustic is available at 6 kg/cm2g at the
battery limit.
Technical Problem:
1. The outlet temperature of oxidized caustic/vapor
mixture from WAO process cooler (116-EE-802) is
expected to be 50OC. But due to leaking of tube side
oxidized caustic/vapor mixture between the different
passes of the exchanger, the cooling effect has not
been achieved.
2. Outlet process fluid temperature was dropped by 10OC
through external water cooling.
Remedial Actions taken:
A brain storming session was done among all the team
members in order to analyse the problem and arrive at the
solution. It was decided to thoroughly inspect the
complete system as per the installation and O&M manual.
As discussed above, WAO Process Cooler was unable to
cool the oxidized spent caustic and vapor. Thus the
exchanger was opened in both fixed and floating head
side. It was observed that inlet fluid stream from tube side
goes to outlet nozzle without travelling the entire tube
length which is due to leakage through the joint at the
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
partition and fixed tube sheet of the exchanger. It is
decided to attend the problem as per below action plan:
1. Change of channel head side tube sheet gaskets.
2. Gasket changed but no improvement observed.
3. Inspection of partition portion at channel and
floating head side.
4. On floating head side groove found ok. On
channel head side no groove was observed in the
partition plate. Also, the welded tube end has
resulted in loss of evenness of the tube sheet face.
This unevenness was corrected.
Brief Details of the jobs done:
Since there was no
temperature drop of
oxidized caustic/vapor
mixture at tube side outlet
of WAO process cooler
hence initially the outlet
line had to be cooled
through external cooling
by water spraying.
For finding solution of the problem, thorough inspection
the system was done by the team.
Considering that no heat transfer was observed in the heat
exchanger, there is confirm possibility of inter pass
mixing of the tube side fluid without travelling its entire
length. Based on the observation, the following actions are
being taken.
OPTION-1: Tube sheet side and end flange side gasket of
the channel head and floating head gasket are changed.
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
Leakage checked through water and it was found that
while water was allowed to enter to pass through drain
point, it instantly passes through the balance drains.
OPTION-2: Belzona adhesive was used while fixing the
gasket, and during leak checking as per above procedure,
no leakage was observed. Thus, the exchanger was
allowed to be in line, but temperature was not dropped
below 70OC.
OPTION-3: Belzona adhesive was used and metal braded
sheet gaskets were used in both sides of the channel head.
During leak checking as per procedure at Option-1 above,
no leakage was observed. Thus, the exchanger was
allowed to line. This time temperature dropped below
50oC was achieved but it sustained for approx. 3 days.
From the outcome of Option-2 and 3 above following is
concluded.
1. In the SS jacketed gasket in partition with spiral
wound at outer periphery, the partition planes at
channel head could not compress the jacketed portion
at the tube sheet. Thus the tube side fluid leaks.
2. During use of metal braded sheet gasket, this indicates
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
that the either tube sheet surface or partition planes are
not straight. But the sheet gasket accommodates the
unevenness and the leak arrests. But again the sheet
gasket melts due to high temperature above 180OC of
the inlet tube side fluid.
Thus we need to make the uneven face even both at fixed
tube sheet end and channel head end. Also, creation of
groove at the fixed tube sheet shall assist in effective
fitment of the partition plane. Two ways are selected to
create the groove and create evenness, either by coating
material buildup at the tube sheet or by machining.
OPTION-4: The coating material buildup procedure as it
is cheaper is adopted. Grooves were created and the tube
sheet surface was made even. Then the exchanged is
boxed up with SS jacketed with outer spiral wound gasket
and then taken inline. This time temperature dropped was
achieved for hardly one day. The exchanger was reopen to
see the effect and it is observed that the protective coating
and buildup material is completed washed away.
This means that the protective coating and buildup
material cannot resist the effect of oxidized caustic/vapor
mixture.
OPTION-5: The heat exchanger was vertical in nature
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
with floating head side is at the top side. Also the heat
exchanger was installed within a structural enclosure.
Thus, the tube bundle cannot be removed for modification
purpose. Hence, in-situ machining method is adopted.
Grooves were created through in-situ milling operation.
The tube sheet surface and the partition planes at the
channel head were made even by in-situ machining. An
offset of 0.5mm was kept between the grove and the outer
machined surface at the tube sheet to cater the difference
in different compressibility of the SS jacketed and the
spiral wound portion of the gasket.
Additionally, leak was observed from the joint between
end flange and the channel head flange. On opening it is
observed that channel head lower flange and end flange
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
has eroded by 2-3 mm at multiple locations, which was
not observed earlier. Thus, bottom flange of the channel
head was built up with suitable welding filler.
Similarly, the end flange after metal build up activity was
carried out at end flange adjacent to channel head bottom.
Then, in-situ machining was carried out at the of the
partition plane of the bottom flange of the channel head
and at the end flange side.
Then the exchanged is boxed up with SS jacketed with
outer spiral wound gasket and then taken inline. This time
temperature has successfully dropped below 50OC and is
sustaining from 17/01/19 till date.
BRAHMAPUTRA CRACKER & POLYMER LIMITED QUALITY CIRCLE PROJECT - STATUS REPORT
WORK CENTER: BCPL As on: 15/02/2019
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
Results:
1. After installation of gaskets and box-up with above
modifications, the outlet temperature of oxidized
caustic/ vapor mixture from 116-EE-802 has been
achieved at 28OC.
2. Due to drop in outlet temperature of oxidized
caustic/vapor mixture coming from 116-EE-802, now
the pH can be more accurately measure/controlled,
hence proper neutralization of the waste going to
waste water treatment plant can be achieved.
3. Through neutralization of waste, material erosion in
piping and static/rotating machinery can be avoided.
4. Hence the performance of WAO process cooler of
Ethylene Cracker Unit (ECU) of BCPL, Lepetkata
has been restored.
6. Target Date for Completion: 15/02/2019
7. Potential Benefits:
a) Tangible:
1. Reduction in maintenance cost.
2. Now no requirement of additional water to be sprayed
in the outlet line to achieved the desired temperature.
3. Improved housekeeping of the area due to external
water spraying.
b) Intangible: 1. After the modification, the heat exchanger is working
as per design parameters.
2. Frequent maintenance of the heat exchanger has been
minimized.
8. Achievement till date: The waste water system performance of ECU has been
restored through control in outlet temperature of the
oxidized caustic/vapor mixture.
9. Implementation Status:
Implemented: YES / NO
If NO, reasons:
Yes, implemented.
10. Counselor’s Remarks: Not required.
BRAHMAPUTRA CRACKER & POLYMER LIMITED
QUALITY CIRCLES: SHARING THE SUCCESS STORY ’18-19
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
Forwarded to: Total Quality management Group
1. Name of the work center: BCPL
(Project registration. no. BCPL/LEP/MECH/ECU/QC/03 dated 15/02/2019)
2. QC Team Name: Explorer
Team Leader : Mr. Ranabir Tarat
Members : Md. Kalamuddin
Mr. Nabajit Das
Mr. Nitul Kalita
Mr. Pankaj Kumar
Mrs. Niharika Kakati
Mr. Angshuman Gogoi
Mr. Chandan Dowari
Mr. Polakh Protim Boruah
3. Champion/HOD: Mr. Pranjal Kakoty / Mr. R. P. Singh
4. Project Title: Performance restoration of WAO Process Cooler of Ethylene Cracker Unit
of BCPL, Lepetkata.
5. Reason for selecting the project:
WAO process cooler (116-EE-802) was unable to cool the mixture of oxidized caustic/vapor.
Thus, this hot mixture remains corrosive and erodes the waste water neutralization drum and its
associated downstream piping, pump and heat exchanger.
6. Outcome of the project/suggested modification or improvement:
1. After installation of gaskets and box-up with above modifications, the outlet temperature
of oxidized caustic/ vapor mixture from 116-EE-802 has been achieved at 28OC.
2. Material erosion in piping and static/rotating machinery can be avoided.
3. The performance of WAO process cooler of Ethylene Cracker Unit (ECU) of BCPL,
Lepetkata has been restored.
4. In future tube bundle and channel head with proper provision for gasket placement shall
be ensured so that inter pass leak does not arise.
7. When from solutions/counter measures were implemented: 17/01/2019
8. Effectiveness of implementation:
After the modification, the heat exchanger cooling effectiveness has been restored.
BRAHMAPUTRA CRACKER & POLYMER LIMITED
QUALITY CIRCLES: SHARING THE SUCCESS STORY ’18-19
(Ranabir Tarat) (Pranjal Kakoty) (R. P. Singh)
Team Leader Champion HOD
Forwarded to: Total Quality management Group
9. Tangible benefits achieved:
1. Reduction in maintenance cost.
2. Now no requirement of additional water to be sprayed in the outlet line to achieved the
desired temperature.
3. Improved housekeeping of the area due to external water spraying.
10. Intangible benefits achieved:
1. Frequent maintenance of the heat exchanger has been minimized.
2. Due to drop in outlet temperature of oxidized caustic/vapor mixture coming from 116-EE-
802, now the pH can be more accurately measure/controlled, hence proper neutralization
of the waste going to waste water treatment plant can be achieved.
3. Through cooling the corrosive effect oxidized caustic/vapor mixture shall reduce which
helps in reduction of erosion in piping and static/rotating machinery involved in the
associated downstream system.
11. Is there any opportunity of horizontal deployment in other departments or work center(s):
This type of job in case of heat exchanger may be implemented when it is not possible to
dismantle due to physical position of the equipment.
Also, method of correction shall be based on physical properties of the working fluid such as
pressure, temperature and corrosive nature etc.