Project description

The project has considered the upgrade, according to a EPCM contracting agreement, of the fluidization and extraction system of five cement stocking silos, in particular of three silos diam. 20m - storage nominal capacity of 8.000 tons/each - and of two silos diam. 12m with storage nominal capacity of 3.000 tons/each. The existing extraction systems (installed from 1978 to 1981) brought to a percentage of non-extractable cement equal to 50% with an actual cement availability of 15.000 tons; thanks to the new project, which was aimed at silos bottoms upgrading, silos nominal capacity has been actually reduced but, on the other hand, a total higher availability of cement, equal to 19.000 tons, has been finally granted.

Also the cement transport system to the packing lines and to the bulk loading has been improved by replacing the existing screw conveyors with new ones, therefore meeting the new potentials required by the client. The two silos diam. 12m are equipped with a unique line; the newly installed screw conveyor assures a capacity of 150 t/h. The three silos diam. 20m are provided with four lines; the new screw conveyors assure a capacity of 150 t/h each, with possibility of simultaneous working of two of them, depending on cement transport downstream the silos.

According to the turnkey formula, TEAMNETWORK scope of supply also included the civil works engineering for modification of the silos bottoms and construction of the electrical room, blower and compressor room; the plant and detail engineering for realization of cement fluidization, extraction and transport equipment; the electrical engineering for manufacturing of the new electrical power and control electrical boards and, finally, the implementation of the plant operating software allowing the data transfer from the central control room to the cement plant.

Details of extraction units – 3D

Arrangement of silos bottom fluidized airslides – 3D

The environmental requirements and workers’ health safeguard have been fully satisfied thanks to the installation of three new bag filters that guarantee an efficient dedusting of the plant, in compliance with dust and noise emission permitted limits.

Scope of supply

  • dismantling and removal of old machines and structures;
  • realization of all necessary civil work such as the ones related to the control room, the blower and compressor room, cable troughs, modification of silos concrete bottoms, drilling of the existing tunnels for installation of new extraction units and air fluidization piping passage;
  • supply and assembly of air-conditioning and ventilation system in the electrical room, blowers and compressor room;
  • supply and assembly of fluidization and extraction airslides at silos bottoms with installation of protective tunnels in steel, extraction unit with valves, blowers for fluidization air and relevant distribution piping, compressor unit with compressed air lines, screw conveyors for cement recovery and transport;
  • supply and assembly of three bag filters for dedusting of silos extraction and screw conveyors;
  • supply and assembly of new radar level indicators and max level probes for the five silos;
  • supply and assembly of plant electrical power and control boards with PLC, supply of electrical cables and cables raceways, with relevant installation and on field connection.

Mechanical and electrical assembly, which were entrusted to the Tunisian company SCMMI (TEAMNETWORK local partner), were constantly and assiduously supervised by TNW mechanical and electrical specialists. Blank tests, commissioning and training of the local staff involved the essential support of all TEAMNETWORK specialists on site.

Project timeline

In 2010 Les Ciments de Bizerte announced an international tender for the upgrading of the fluidization and extraction system of five existing cement silos. The study of the plant and detail engineering, the manufacturing of mechanical equipment and electrical panels, the purchase of the plant components and machines had been already completed by May 2011, when all materials were delivered CFR port of Tunis according to Incoterms 2010.

Assembly activities, which began at the end of 2011, have been protracted until Spring 2015, being considerably conditioned and delayed both by cement shipping needs of the cement plant and by the difficulty, which the company in charge of emptying the cement from silos had to overcome, in extracting big quantities of hardened cement out of them.

The plant was started in five blocks in sequence, without compromising the working of the rest of the installation, and required the arrangement of provisional connections and development of a special software for the partial operation of it. Also this final test has been the proof of the great commitment and high professional competence of the TEAMNETWORK specialists