Down Mexico Way
08 May 2008
Early this year Sarens Ojeda was awarded a demanding transportation and lifting job by main contractor Kepler at a refinery in Coazacoalcos, Vera Cruz, Mexico. Sarens Ojeda, a joint venture between Belgian heavy lifting specialist Sarens and local company Ojeda, was formed in 2002.
The contract was for the transport, lifting and installation of a 37 m long, 344 tonne reactor and a 49 m long, 178 tonne product purge bin (PPB).
The first task was to load the reactor onto Scheuerle self propelled modular transporters (SPMTs). This was done using a 400 tonne maximum rated capacity Demag CC 2400 crawler crane and a 600 tonne maximum rated capacity Demag AC 1600 telescopic wheeled mobile crane. The SPMTs were configured with 24 lines of axles, in two rows of 12.
The fabrication area, where both the reactor and PPB were to be unloaded and erected, was located 1 km away from the loading area. Difficulties that needed to be overcome along this journey included a downhill gradient, a 90 degree left hand curve and overhead pipes that gave just 200 mm clearance. To ensure the curve could be negotiated safely, it was adapted with a 20 x 21 m increase in the bend, and the gradient was decreased over a 30 m area.
Once the reactor reached the installation area, an 800 tonne maximum rated capacity Liebherr LR 1800 crawler crane was used to place it. The crawler was rigged with 77 m of main boom, 238 tonnes of carrier counterweight, 142 tonnes of central counterweight, and 220 tonnes of superlift counterweight at a radius of 25 m, which gave a lifting capacity of 369 tonnes. Tailing crane was the Demag CC 2400 crawler, rigged with 30 m of main boom and 130 tonnes of carrier counterweight.
To complete the rotation of the reactor and put it in a vertical position, the CC 2400 had to travel 24 m on timber mats, with a final radius of 12 m, while the LR 1800 was working at 22 m radius. The reactor had to be swung over the corner of the lower supporting structure for the purge bin, which stood 10 m high.
The second part of the operation was to load, transport and install the PPB. Again, the CC 2400 crawler, with 30 m main boom and 130 tonnes of carrier counterweight, and the AC 1600, rigged with 30 m of main boom and 98 tonnes of carrier counterweight, were used to load the structure onto the SPMTs. Both cranes were working at 90 % of their lifting capacity.
Although the PPB was not as heavy as the reactor it was considerably longer so the transport system was redesigned, again using the Scheuerle SPMTs. This time, however, the configuration was 2 x 4 axles connected side by side at the front taking a 41 tonne payload (38 % of its load capacity) and 2 x 8 axles connected side by side at the rear taking a 136 tonne payload (52 % of its load capacity) with 285 mm clearance under the pipe rack.
Because the PPB had to be lifted up and over the support structure and landed through the middle, the LR 1800 had to clear the top of the structure, which was at a height of 52 m. To do this, the crane had to be re-rigged with 126 m of main boom, 238 tonnes of carrier counterweight, 142 tonnes of central counterweight and 200 tonnes of superlift counterweight at a radius of 34 m, giving a total lifting capacity of 190 tonnes. Again the CC 2400 was used as the tailing crane in the same configuration for the reactor.
Various other lifts were also undertaken, which included a 112 tonne heat exchanger installed using the CC 2400 at ground level, and an 84 tonne PPB module which was installed using the LR 1800 at an elevation of 51 m.
Sarens Ojeda supplied a full project management team and all lifts were undertaken and completed on time and more importantly to the client, all the heavy lifts were placed first time.