2014-2015 Exhibitions
UK-based Closed Loop London, which produces food-grade recycled PET and HDPE from plastic bottle waste at its plant in Dagenham, has expanded its plant capacity to 4,800 kg/hour, with suppliers B+B Anlagenbau (Germany) and Erema Engineering Recycling (Austria) providing the technology. The latter suppliers provided the technical solution for this pioneer work when the plant was set up in 2008.
The processing steps comprise Dry cleaning – Air classification – Hot wash – Sink float separation– Mechanical drying from B+B and subsequent extrusion with upstream decontamination from Erema. This process enables Closed Loop to produce rHDPE pellets from HDPE milk bottles for direct food contact in line with efsa requirements.
The basic principle of B+B's plant concept is to treat the regrind material in a dry state as long as possible while it is in the process. This means that expensive resources such as water can be saved and no elaborate plant engineering is required for processing.
The core component of the washing facility is the hot wash that removes any unwanted elements such as stickers or adhesives from the regrind material. This particular application also features the removal of milk residues and the associated odours as a crucial part of the cleaning process. The hot wash system works continuously and is fully automatic to ensure maximum availability and minimum maintenance intervals.
In the subsequent extrusion process food contact grade HDPE regrind material is made on two Vacurema Advanced 1716 TE systems from Erema. The material is then reused in the production of milk bottles. Closed Loop ordered what is now the third of these systems – each with a capacity of 7,000 tonnes/year – as part of the expansion.
Erema says its Vacurema technology has a market share of 50% in the US and 30% in Europe, and that it has proven itself on a global scale. The concept also works in a slightly modified form for the recycling of food contact grade HDPE pellets that requires an additional extruder degassing.
Erema also says the deciding success factor of Vacurema is above all the efficient, food contact compliant decontamination upstream extrusion process. The patented pre-treatment of the HDPE flakes at raised temperature and in high vacuum before the extrusion process removes moisture and migration materials from the feedstock effectively and in a stable process environment.
Another benefit for the user is that the parameters for direct food contact compliance are monitored and archived continuously in the recycling process on all Vacurema systems. The Food Contact Control (FCC) feature supervises the recipe data stored and if levels go beyond defined limits an alarm is triggered automatically and (optionally) material flow is diverted away from current production.
Higher-quality washing processes have posted significant growth in recent years as the cold wash used previously for the processing of polyolefins was not able to remove what was in part a strong odour. If these plastic regrind materials are then extruded, the end products made from them are often suitable only for outdoor use.
Meanwhile, the Austrian firm says a number of potential users are now looking into using more enhanced processes such as those offered by B+B for the production of odourless recycled pellets. In the US, for example, polyolefin repellets are already being used in the washing detergent and cosmetics industries. B+B has commissioned hot wash systems of this kind for HDPE around the world with a capacity in the region of 90,000 tonnes/year.
(PRA)
