Two units of Mitsubish MB3E

Part I—Description of scope of work

Part II—Fabrication in workshop

Part III—Retubing on site

Part I—Description of scope of work

Background

Boilerman was requested to carry out complete retubing of two units of Mitsubishi MB3E type boilers in HRDD in Shanghai.

The retubing was confirmed in mid of March while job needed to be started in the beginning of April and completed within 70days.

All the materials incl. super heater tubes and supports were sourced locally in China and fabricated in Boilerman Shanghai workshop.

With the great support from HRDD, ship owner and management company, the job was completed within 70days as per the agreement and to the client and LRs satsifactory.

Scope of work:

• Complete renewal of front and rear wall tubes *2boilers
• Complete renewal of generating tubes *2boilers
• Complete renewal of superheater tubes *2boilers
• Complete renewal of superheater support tubes *2boilers
• Complete renewal of screen wall tubes *2boilers
• Complete renewal of floor, side, roof wall tubes *2boilers
• Complete renewal of de-superheater and control de-superheater*2boilers
• All Burner tiles, insulation, refractory *2boilers

Part II—Fabrication in Workshop

The fabrication of the material was carried out in parallel with the retubing work on site. Sample tubes were cut out and sent to the workshop for bending, swaging, making panels, assembling, NDT, pre-hydro test, etc.

Some sample tubes cutting from the boiler--Generating tubes, Manhole tubes, De-Superheater coils

New tubes arrival in workshop incl. SH tubes

Fabrication of tubes

Fabrication of Superheater Panels

Part II—Retubing on site

As the job was confirmed in short notice, a mixed team with one British Project Manager, one Indian Supervisor, four Chinese Supervisor and forty+ people (Chinese, Indian, Pilipino) were gathered together for the site repair. A daily report as well as a progress S curve was reported to the client at the end of day shift.

Remove insulation and cladding	Remove furnace floor refractory	Remove superheater floor refractory

Cropping out the tubes	Cropping out the tubes	Cropping out the tubes

*Sufficient support tubes to be left to make sure headers and drum not sagging down

Splitting of tube ends	Removal of tube ends

Grinding/Polishing tube holes	Removal of weldings at SH tube ends	SH tube ends punched out

NDT (PT) on tube holes

Install and weld of the front/rear enclosure tubes

Install and weld of the front/rear wall tubes

Install and expand the generating tubes

Install and expand the superheater support tubes	Install and weld the screen wall tubes

Install and weld the superheater tubes

Install and weld/expand the floor, side, roof wall tubes

Butt joint welding and X ray	Welding all the fins/flat bars

Closing the boiler for hydro test

Hydro test of both boilers

Install the new DSH/CDSH and hydro test

Install the refractory in way of repair

Install the insulation, cladding and manhole covers