8/3/2019 DC5 Shell Plate Leak
1/7
PRELIMINARY INVESTIGATION REPORT
DC #5 SHELL PLATE LEAK
1.0 Event
Date : 05th November 2011
Time : 10:20 am
Heat No. : 5055443
A. DC# 5 shell plate below KT3 leak; happen during
tapping. The root cause of leakage was the bricks bad
condition consequence from water leaking of panel WCP 1-9
at 15 October 2011 and loose of coupler supply water WCP
1-11 on 05 November 2011. Tap temperature high due to
over arching worse the bricks condition.
B. History of Incident
Date Heat No. Event
04.10.2011 5054917Slag penetrate below KT3Patching with castable and gunning
15.10.2011 5055097 Panel WCP 1-9 leak
27.10.2011 5055204 F/hose cooling block KT8 leak
29.10.2011 5055338 Panel ECJ and RCP leak
01.11.2011 5055377 Tap temp 1651 C,O2 ppm 288 ppm
03.11.2011 5055405 Tap temp 1628 C,O2 ppm 556 ppm
03.11.2011 5055413 Tap temp 1630 C O2 ppm 745 ppm
03.11.2011 5055422 After hot repair Tap temp 1628 C O2 ppm 577 ppm
04.11.2011 5055432 Over shoot tap temp 1647C ladle preheater
04.11.2011 5055433 Gunning 1698kg
04.11.2011 5055438 Gunning 1528kg
05.11.2011 5055443Coupler W/return WCP 1-11 looseShell plate leak during tap
8/3/2019 DC5 Shell Plate Leak
2/7
8/3/2019 DC5 Shell Plate Leak
3/7
2.0 Preliminary Causes
Based on our investigation, the leakage happens due to :-
1. The bricks area under KT 3 was very bad condition. The bricks
heavy erosion due to effect of water leaking from WCP 1-9 at
15 October 2011 and water leaking from loose coupler WCP 1-
11 at 05 November 2011.
2. Temperature high up to 1651oC due to overarching. Furnace
operation increases the temperature for ladle parking, ladle
preheater and after hot repair. The S.O.P required normal tap
temperature only 1610oC and 1630 oC for ladle preheated.
3. DRI was very low quality with high silica content 3 % required
furnace to use high amount of CaO 3500 per heat.
3.0 Equipment Damages
i) Shell Plate under KT 3
ii) Bricks area KT 3
iii) Bottom furnace Sensor and Cable
iv) Limit switch Tapping lock post
v) Hose cooling busbar
vi) Bottom electrode
4.0 Preventive Measure
1. To focus gunning at the high erosion bricks consistently.
2. Detail Check furnace condition once stoppage/onpeak schedule.
3. Dont delay the gunning activity schedule for safe mode.
4. Change the high erosion bricks or collapse bricks as quick as
possible.
5. DR plant must plan for high quality DRI on the future consistently.
8/3/2019 DC5 Shell Plate Leak
4/7
5.0 Cost Of Damages
Shell Plate repair RM x
New Bricks RM xBottom electrode RM x
Bottom furnace Sensor and Cable RM x
Busbar cooling hose RM x
Tapping lockpost limit switch RM x
Man Power RM x
Total Cost RM xxxx
Prepared by, Checked by,
Mohd Zakaria Khamis Mr. Abd Rahman Che Min
Mohd Nasuha Abd Halim
8/3/2019 DC5 Shell Plate Leak
5/7
ATTACHMENT
Picture 1: Shell plate leak below KT3
KT3 KT8
Leak area
8/3/2019 DC5 Shell Plate Leak
6/7
Picture 2: Brick condition below KT3 after incident
KT3
8/3/2019 DC5 Shell Plate Leak
7/7
Picture 3: Below furnace