The Adige Bitumi S.p.A. Group recently decided to renew its by now historic M 260 plant located in the Mezzocorona (TN) job site with a new plant and, in doing so, decided to place itself at the top of the Italian market, choosing to collaborate with Marini S.p.A. for the design and development of a plant with production of 280-300 t/h which can certainly meet the needs of the Italian market with specific reference to new technologies.
The primary input during the initial phases of the negotiation was that of being able to prepare a high potential plant (to best meet the needs of the clientele and its own paving crews), but above all to have a plant which is very best on a global level specifically with regard to the technological-ecological aspects (low atmospheric emissions, low noise, low energy consumption, maximum percentages of usable milled materials, possible use of all types of liquid and solid additives, etc…) and also the modularity (use of mobile metallic bases, external electrical wiring, etc…).
The owner, Paolo Tellatin, with his technical team had very clear ideas, thanks to the extended experience acquired on their own job sites (the group has five installations between Veneto and Trentino, besides a sixth plant installed in Belgrade) and so it was easy to find the right feeling in designing a plant so complex which, however, had to be placed in the same space as the old plant.
The plant was designed with a high number of pre-dosing units (12 for aggregates + 3 for the pre-processed and selected milled material) in order to guarantee maximum precision in dosages, also with an unequalled operational elasticity. It is also possible to feed the “hot” recycled material line at the recycling line with 2 pre-dosing units and the “cold” line in the mixer with 3 pre-dosing units (remaining in the spirit of being able to guarantee the highest quality products in any operating condition). Naturally, all of the conveyor belts were encased to be able to reduce the emissions into the atmosphere.
Thanks to the advantages of the “Drying tower” with the bag filter and the storage silo for the fine products located directly above the Drying drum, the MARINI TOP TOWER 4000 limits not only the ground dimensions, but above all guarantees optimisation of the heat energy balance (reduced length and insulated exhaust duct between the dryer and bag filter) and also the recovery of energy radiated from the drum. With particular reference to the concepts of reducing emissions and sustainable development, the Dryer burner was equipped with further atomization of the fuel with a dedicated air compressor and the plant was equipped with a Bag filter with an increased filtering surface as well as sleeves in Nomex 500 material.
With regard to the filler as well an optimisation never before achieved in Italy was realised. In fact, the plant is equipped with 2 separate silos for recovery of the fine products besides a silo for the intake filler, a cement storage silo and another for lime storage.
The use of a 6 selection screening unit was decided on for the mixing tower (in the completely covered version with significant reduction of noise and heat loss) with great ease of screen replacement and maintenance thanks to a new Marini patent which guarantees easy replacement of the screens and complete accessibility to them.
Maximum attention was given to ease of maintenance with direct and easy access to the 6 hoppers under the screening unit (besides to the direct discharge which was heated with electrical elements in order to optimise use of the milled material) as well as to the stairs and handrail complex (widened as required by European standards) which allow all of the plant maintenance points to be reached without having to descend to the ground once leaving the cab.
Significant care was also given to the aspect of reducing noise and atmospheric emissions and, from this point of view the coverings of the mixing tower and the finished product storage silo (with high storage capacity of finished product – more than 400 tons) were realised, also including the conveyor shuttle level. The bag filter with the entire drying tower were covered with roofs overhead and protective folded roof sheeting on the sides.
The cisterns have rock wool insulation with increased thickness at 200 mm (even on the bottom) in order to be able to reduce heat loss to a minimum and consequently consumption for heating the bitumen. 5 bitumen cisterns are provided with a capacity of 100 m3 each, 1 for combustible oil (capacity 100 m3 and 1 emulsion cistern divided into 2 compartments (60 m3 + 30 m3) to feed the plant spraying cisterns separately. 3 plant feeding lines were provided: 2 for bitumen with the possibility of blending (mixing 2 different types of bitumen in the same mixture to obtain a bitumen with intermediate characteristics) and also 1 emulsion line to be able to produce cold conglomerates.
The extensive efforts of the alliance between the Adige Bitumi Group and Marini S.p.A. led to the creation of a plant which promises to be a point of reference for a new, evermore demanding clientele which is more and more oriented toward quality as a key factor in order to attack the modern market while at the same time paying more and more attention to energy savings, environmental impact and company economy.