Radiant Coil Repair Procedure in Cracking Furnaces]
This procedure applies to Cracking Furnaces ( 11-FH-201/205)
2 EQUIPMENT NAME (SERVICE)
3 TAG NUMBER OF EQUIPMENT
5 SAFETY, HEALTH & ENVIRONMENT PRECAUTIONS
5.1 PROTECTIVE EQUIPMENT
6 MATERIAL NEEDED
7 TOOL LIST
8 MAINTENANCE PROCEDURE
9 CHECK LIS
10 DEVIATIONS FROM PROCEDURE
11 SUGGESTION FOR improvement
12 References & Attachments
Key terminology used in this document is either defined on its first occurrence or takes the common definition as stated in the;
1.1 WPS: Welding Procedure specification.
1.2 ID Fan: Induced Draft Fan
1.3 DM Water: Demineralized Water
2.0 Equipment Name:
Cracking Furnace Radiant Coils
3.0 Tag Number of equipment:
Radiant Coils for Furnace 11-FH-201/205
1. Shift Supervisor( Operations)- For making system ready for maintenance.
2. Maintenance Supervisor: For Job execution and Job planning before the start of the job and history Updating.
3.Maintenance Technician: To follow work instruction and time logging.
4.Maintenance Engineer: To ensure the availability of the procedure for the job.
5.0 Safety and Environmental Precausions:
5.1 The radiant coils will become very brittle in nature in aged condition. Hence the coils need to be supported at several places if coils are to be cut for maintenance.
5.2 The location of joint has to be decided keeping in view of the safety of the persons working and welder convenience. If possible the joint to be made at floor level.
5.3 When persons are working in the fire box, ensure that radiant coils are not blown with Nitrogen.
5.4 Ensure that ID Fan is running and firebox is sufficiently ventilated.
5.5 Only 24 Volts hand lamps should be used in side the firebox.
5.6 All the hydrocarbon lines are to that Furnace to be positively blinded.
5.7 Scaffolding/ Platforms to be arranged as per standards.
5.8 Fire box manholes on both sides to be opened for persons to enter into the firebox.
5.9 Before cutting the coils, ensure that they are supported at as many locations as possible with the help of chain blocks, nylon ropes.
5.1 Personal Protective equipment to be used:
- Hard hat
- Eye protection
- Safety belt for the welder
- Safety shoe
- Dust mask
- Disposable Coveralls
6.0 Materials Needed:
- Filler wires as per the “WPS”
- Scaffolding material.
7.0 Tools required:
1.Chain Blocks( 1 or 2 Tons capacity)
2. Nylon rope
3. TIG- welding set with necessary filler wires( See attachments for Details)
4. Clamps for fit up.
5. Thermo chalks
6. Boroscope to check inside the coil
7. Hydrojetting machine if the coils need dechocking.
8.0 Maintenance Procedure :
8.1 The following permits to be obtained from Operations department for radiant coils repair job:
1. Cold work Permit.
2. Hot Work permit.
3. Confined space entry permit
8.2 Cutting / Edge preparation and Rewelding:
1. The orientation markings to be made before cutting the coils. Otherwise the fit up will be proper as they have bow.
2. Ensure that nitrogen pressure is not there in the coils before cutting and minimum thickness of the cut off wheel should be used to part the coil.
3. The coil parts are to be taken out of the fire box for dechocking by hydrojetting.
4. Ensure that the markings made on the coil with crayons do not contain sulfur.
5. See the attached WPS for the details related to the edge preparation, filler wire specification, and Procedure.
6. Ensure that interpass temperature does not go beyond 150 Deg C.
7. For rewelding, the clamps can be used for proper fitup and Tack welding. Ensure the sufficient inert gas flow inside the coil.
In this case ,the pure Dry nitrogen from utility header can be used. Ensure that ID Fan is running and maximum air is sucked through the fire box in which welding is to be carried out. Keep monitoring the oxygen level at the work place continuosly and masking tape is to be used to minimise the nitrogen coming in to the fire box during welding. The persons involved in this needs to be given tool box talk accordingly.During execution of the welding when nitrogen is used for purging portable Oxygen alarm to be used. A radio communication has to be established between welder and the Operator who has to immediately close the nitrogen valve in case of unacceptable nitrogen concentrations in the work place.
8.3 WPS :
For WPS( Welding procedure Specification) See attached WPS by the supplier of the coils” Paralloy Limited”
1.Inspection will be as per “ WPS”
2.Pneumatic Test to be done before taking coils into line.
3.All fit up markings to be removed or to be cleaned with some solvent.
8.6 Normalizing the system:
1. All blinds to be normalised.
2. Leak checking to be done for all disturbed flanges at operating pressure.
3. Work permits to be closed and returned to Operation Department
4. All high temperature flanges are to be hot bolted when furnace being brought up.
9.0 Check lists : NA.
10.0 Deviations from Procedure
Deviations from the requirements of this procedure are not permitted without a written waiver formally authorized and recorded in accordance with the “Incident Reporting” procedure.
11.0Suggestions FOR IMPROVEMENT
Employee contribution to the effectiveness of the way Borouge conducts its business is welcomed. Any employee of Borouge may suggest changes / revisions to this procedure by completing a “Request for Improvement” form as per the “Incident Reporting” procedure.
Request for Improvement” form as per the “Incident Reporting” procedure.
12.0Reference and Attachments:
WPS by the supplier” Paralloy Limited”