engro fertilizers - muhammad azhar mailk.pdf
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Incorrect Steam Drum
Level Measurement Can
Result In Multiple
Issues At Ammonia
Plant Muhammad Azhar Malik
Feb 26, 2015
Purpose of Paper
Root Cause Analysis
26 February 2015 2
Purpose of Paper
Sharing Engro's experience on issues faced on HTSC catalyst early
deactivation, waste heat boiler fouling, turbines fouling post new
fertilizer plant successful startup mainly due to incorrect Steam drum
Root cause analysis of problems encountered
Remedial measures taken to overcome problems.
26 February 2015 3
26 February 2015 4
Worlds Largest single-train Ammonia-Urea complex at the time of
Successfully Commissioned in Dec 2010.
Steam Header Network Configuration
KS Steam 110 kg/cm2
HS Steam 44 kg/cm2
LHS Steam 41 kg/cm2
LS Steam 3.5 kg/cm2
Steam Network Configuration:
110 kg/cm2 Steam Drum
42 kg/cm2 Aux
Process Steam to Furnace
Heat recovery from WHB Sec Ref / HTS / Amm Convertor
KS Super heater
CO2 Comp Turbine
PA Comp Turbine
ID fan Turbine
Lube oil Turbine
HS Network 44 kg/cm2
LHS Network 41 kg/cm2
LS Network 3.5 kg/cm2
26 February 2015 6
HTS Catalyst Failure
26 February 2015 7
HTS Catalyst bed undergoes replacement just after two
effective years of operation.
Plant load got limited due to high delta pressure across HTS
bed - 1.8 kg/cm2
The temperature profile across catalyst bed showed signs of
26 February 2015 8
HTS Bed Radial Temperature profiling
26 February 2015 9
Window - 1
Window - 2
Window - 3
Window - 4
Window - 5
Window - 6
ACTIVE PORTION (~42% of circumference)
DEAD PORTION (~58% of circumference)
26 February 2015 10
2ft catalyst bed shrinkage Channelling Signs in
26 February 2015 11
Dust at Al balls at HTS Top Analysis showed
7% Sodium & 1% Silica contents
HTS Failure - Root cause Analysis
26 February 2015 12
Inspection revealed Presence of
Shrinkage of 2% catalyst bed with clear signs of channeling
High contents of foreign particles especially Sodium & Aluminium
Crushed catalyst due to increased delta pressure operation
Presence of Sodium questioned steam quality
Presence of Aluminium showed slippage from alumina lumps
from Secondary reformer
26 February 2015 13
Temperature at WHB outlet increased by 25 C.
Inspection showed fouling of WHB tubes
Analysis of dust revealed presence of Sodium and Aluminum.
A lot of dust was also collected at WHB cold end showing
slippage from secondary reformer
26 February 2015 14
WHB Tube Fouling Dust Analysis Showed
Sodium 8% and Aluminum 18%
BFW Turbine Fouling /Internal seals Failure
26 February 2015 15
BFW turbine TP-1301 A efficiency dropped significantly.
BFW header pressure reduced by 4 kg/cm2.
Upon inspection, interstage seals of the turbine was found
Rotor was found covered with heavy deposits.
Analysis showed presence of 40% Sodium contents.
Table 4: Deposit Analysis at TP-1301 A
Componenet Analysis result
26 February 2015 16
Deposits of Sodium on Turbine Interstage seal
26 February 2015 17
Deposits of Sodium on interstage seals
ID fan Turbine Fouling
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ID fan Turbine vibrations increased till the danger level till 0.34
Efficiency of turbine also dropped significantly
Inspection showed presence of deposits sodium on the rotor
26 February 2015 19
Fouling of ID fan Turbine Rotor
Root Cause Analysis
Prime reason of above mentioned problems was High quantity of
sodium in Steam.
Sources of Steam
Steam Drum 110 kg/cm2 Heat recovery from WHB at ammonia
Auxiliary Boiler 42 kg/cm2
The reason for poor steam quality was incorrect steam drum
level measurement and its control.
26 February 2015 20
Steam Drum Level
Level remained higher then normal causing poor steam quality.
26 February 2015 21
Marks of High
Correction of Level Measurement
Algorithm for level correction was corrected for correct level
Steam Drum equipped with 02 new DP type transmitters in addition of
03 float type meters
Steam Drum equipped with Conductivity Meter
Isolation Valves at Steam drum rectified.
Maintenance regime for floats of level transmitter at every 6 month
26 February 2015 22
Wet Washing regime for Turbines was implemented.
Make up water Quality improved
RO unit and DMW beds were lined up in series
Conductivity dropped to 0.2 us.
DMW is then passed through Polisher to fed to Steam drum.
Steam header Wet Washing
Entire steam headers wet washing carried out
26 February 2015 23
By taking above mentioned steps, Steam quality improved
26 February 2015 24
26 February 2015 25
Thank You !!!