Donaldson Australasia has been central in a waste handling recycling loop aimed at maximising environmental control at a bill processing plant in Sydney.
The company’s engineers configured and installed a system to collect all paper edged trimmings at one of Salmat BusinessForce’s NSW production sites, with all waste eventually passed on to specialised paper and cardboard recycler ,Visy Recycling.
Dominique Ollitrault, Donaldson’s chief engineer on this large-scale project, had three main objectives and client expectations from this ‘Paper Waste Disposal System’:
• To improve on the waste management system.
• To improve on preventive maintenance, e.g. labour cost in housekeeping
• To meet the EPA requirement (dust emission to atmosphere)
The project, financed by Visy Recycling, sees paper edge trim gathered by suction at various collection points in the printing section of the operation and conveyed by ducting to a compactor and paper dust collection unit.
As an outsourced provider of bill production services (variable and non-variable data) to many large corporations such as banks and financial institutions, Salmat BusinessForce is responsible for a significant proportion of Australia’s business mail.
This installation at Moorebank (in Sydney’s south west) is designed to operate 24 hours per day, seven days per week. Equipment is sized for heavy-duty operation and reliability has been the guideline of all technical choices.
“There are various workstations that edge trim section for rolls of paper which adds up to a fair amount of waste paper which is then transported for recycling," said Ollitrault.
"With a high-volume of outsourced billing going through the processes at Salmat, the company is trimming about 1,000,000 pages per week and needed a reliable solution to not just collect the waste but also a way to efficiently redistribute it at the end point.
“The site is also near a residential area, so company management also decided that noise had to be kept to an absolute minimum.”
“The system we designed was one that extracts and separates paper trim waste, with a separator rather than a cyclone used for the air/paper separation device to gain greater advantages.
“The principle behind the separator operation, as opposed to a cyclone, is that an inclined baffle plate, situated within an expansion chamber, knocks the product out of the air stream rather than relying on a cyclone’s geometry to cut a specific portion of product by centrifuge and internal vortex.
“The advantages are compactness, flexibility and low energy consumption.”
The system extracts paper trim and dust from various trimming machines on the Salmat processing line. Each machine has its own chopper fan to chop up continuous paper trims to reduce the risk of blockage through the main ductwork system.
All the chopper fans are connected to a common trim-handling fan and ductwork. The product coming from the chopper fans, ductwork and main trim fan is then transported to the separator where strip is separated and returned via a chute into the compactor.
Air and dust is then transported through the dust collector where the dust is separated from the airstream and an air emission of < 15 mg/m³ can be expected.
A rotary valve is fitted at the base of the separator hopper to prevent any air pressure into the compactor - source of pollution (paper trim and dust flying) when changing over bin.
Two 110 litre bins underneath the dust collector collect the dust. The main system, which comprises a trim fan, separator, and rotary valve, is mounted onto a common platform and is located outside. The dust collector and clean air fan are installed on the floor next to the compactor.
“An important aspect of the design of a waste handling system is to make sure that conservative materials handling principles are followed to ensure various problems do not occur,” said Mr Ollitrault.
“Material fallout which could lead to duct blockage, insufficient capture velocity, and that the discharge system does not choke due to positive pressure in the compactor.”
Waste is captured from the machine by means of suction hoods of aerodynamic design specially fabricated in steel welded construction. Each machine is fitted with a specially designed funnel with duct connection at the centre of the funnel to allow homogeneous extraction velocity across the hood.
Captured waste is conveyed through an aerodynamically balanced piping network made of galvanised steel. The purpose of this network is to convey the waste from the machines through the chopper fans and main trim fan where the designated material is then separated from the airstream via the separator. Remaining material is then conveyed to the dust collector where final removal of the particulate from the airstream takes place.
One chopper fan located next to each machine chops continuous trim before being introduced into the main system.
An Air Material Separator is installed on a steel platform above the compactor. A rotary valve fitted at the base of the separator hopper keeps the compactor airtight. Each ducting line is connected to the separator through a transition piece which allows a suitable air velocity at the entrance of the separator.
After the separator, a Donaldson DCE Dalamatic DLM 2/5/15 dust collector is in situ to reverse pulse jet clean the fabric filter with a total filter area of 150 m². The dust collector is also equipped with top explosion and full antistatic provisions.
Dust collected in the hopper is discharged into two 110 litre bins. The discharge equipment has been selected and sized to minimise risk of blockages and maintenance. A dust level detector is fitted into the hopper to warn operators of any problems.
All the chopper fans are electrically connected to a common control panel outside near the main waste extraction system. Each chopper fan motor has its own contactor and circuit breaker.
The trim fan (30 kW) and dust collector fan (30 kW) are operated via their own starters. A high level detector is fitted onto the dust collector hopper which will inform of a dust bin ‘full’ condition. All the necessary circuit breakers, contactors, indicator light and others components are fitted in the control panel.
