The challenge was to provide 15,000 tons processing capacity for bales from the French collection system Valorplast. The facility was completely built at the Holzmag factory in Emmendingen near Freiburg (Germany) and accepted by the client there after performance testing. Since the requirements specifying five tons of 6-mm pellets per hour were more than fulfilled, the order could be completed without customer reservations, and the facility could begin operations promptly.
Completion of the order with building plans and clarification of technical detail prior to start-up lasted about six months
The facility consists of:
- Bale acceptance with bale opening and a wire-winding device, and lifting station with material discharge into a conveyer belt receiving funnel.
- Material feeding with an intermediate buffer for one Holzmag PreciCut multi-edge rotor shredder of the type 730 S (buffer can be extended at a later stage for two PreciCuts). Quality requirements for the shredder consisted of a uniform 30-mm granulate with no fine particles or oversize granulates, which would disturb the following drying process. In the case of extrusion and profile waste from the customer’ own production of pallets, rapid conversion to a 10-mm granulate without pelletizing was requested by the customer. For this requirement, a performance level of 2,500 kg/h is achieved with the Holzmag PreciCut 730 S.
- The Holzmag VB-6 dryer, based on a fluidized bed with scaled-metal-plate and continuous control feeding, was ordered on the condition that the molasses-like fluid from the bottles would not lead to sieve blockages given a maximum of one cleaning per week. The dryer has a drying performance of 500 l of condensation per hour and is supplied by a gas burner and heat exchanger with hot air at about 120 degrees. The humidity in the ventilation is cleaned in a special cyclone-filter and can either be removed or returned to the process following condensation release.
- A metal separator removes debris such as aluminium and metal caps or disruptive metallic materials from the granulate. Separation of mineral and glass-like materials occurs by air suction of the granulate to the cyclone and feeding silo of Holzmag’s pelletizing press.
- The Holzmag Pelletizer Triumphator 1100 is based on Robinson drive technology (with power transmission V-belts and high torque toothed belts, automatic roller adjustment, hydraulic breaks, and dosage control of material). It is the largest ring-matrix press on the market with a matrix press surface of 1.32 m2 and a drive of 2 x 200 KW. It produces 6-mm pellets at a rate of five tons per hour.
- The pellet cooler reduces the hot pellets’ heat to room temperature based on air counter-flow technology and thus cools the pellets with available air. Ventilated air is again passed through the cyclone-filter.
- The “big bags” filling station for finished pellets includes three filling stations that, based on photocell technology, automatically switch to the next station when the preceding one is full.
The complete conveyer-belt equipment had to fulfil the requirements of the various preparatory stages of the system. Hence moist and sticky material between granulating and drying will not lead either to stoppages or disturbance of the conveyer-belt equipment. Special feeding spirals without guiding axes manage horizontal and vertical transport of material without stoppages in this non-stop customer operation. Trough chain conveyors with special stripping devices and various discharge stations with electro-slides tend to distribution of material into “big bags”.
This facility is presented as a pilot project with many new developments to serve as a reference for difficult plastic recycling processes. Holzmag Recycling Technology welcomes further similar test cases in order to benefit from a recurring effect for its new developments.
As Holzmag has also realized one of the largest processing facilities for granulating plastic bottles in Hamburg, it seeks to promote processing in the tubular and bottle sector.