Mechanical Tube Decoking Typical Procedure
1. For protection of personnel and equipment, cool tubes to 300°F or less before beginning work.
2. Erect scaffolding, open header doors, loosen holding member screws, remove and segregate holding members and plugs. Send components to shop for reconditioning as needed.
3. Insert cleaning gun completely into each tube before turning air on. This is to prevent moving cutters from damaging plug seats.
4. While gun is in operation, keep it constantly in motion to avoid cutting rings in the tube. Move gun slowly back and forth, working from near end to far end of tube. Exhaust air blows coke cuttings from the tube, an eye hazard.
5. When all tubes have been cleaned, blow residual coke dust from tubes with compressed air and inspect.
6. Hand-clean plug seats. Hand-clean or use portable air-driven wire wheel buffer to clean plug faces, screw threads, etc.
7. Lubricate screw and holding member threads, coat plug seating surfaces with key paste, install, and tighten. Do not use a sealant like graphite tape on plugs; this will cause future leaks.