Pulper ropes are an unavoidable by-product of the paper manufacturing process. Our sales director, Gary Moore was recently featured in Circular by the CIWM, discussing what paper mills can do with this waste stream. 

If you missed the original article, you can catch up below…

At the start of the pandemic, UNTHA UK was very vocal about the overlooked resource potential that has long remained ‘locked’ in tyres, because they are widely considered difficult – if not economically unviable – to process.

We were passionate about drawing the industry’s attention to this material stream, not least because a staggering 1.5 billion tyres reportedly reach their end of life, globally, every year, and sadly a worrying 60% of these are said to be landfilled, stockpiled, illegally dumped or ‘lost’ from the resource chain.

So, we set out to work with industry, at pace, to address this challenge, and now tyre shredding is the second-most-viewed page area of our website after our homepage! Mattress shredding – another topic to have recently exploded on the waste and recycling scene – is not far behind.

I am not telling you this to shout about how great UNTHA’s tyre and mattress shredders are. The crux of the matter is that this proves that innovators in industry do not just want to settle for what has always been done. They are keen to push for progress, drive greater environmental change and boost the world’s resource security – especially here in the UK.

And nothing drives innovation more than a crisis.

This helps to explain why operators are now thinking more carefully about a wide range of notoriously troublesome wastes, with pulper rag ropes – an unavoidable by-product of the paper manufacturing process – perhaps the next big trend.

While very different to tyres and mattresses, pulper ropes are also often extremely large and cumbersome to handle, as they can reach over 12m in length. They are high in moisture content unless subjected to a mechanical dewatering process, and similarly contain many multifaceted materials – mainly plastic and metal – intermingled together. The true resource potential within this waste stream is therefore limited unless the pulper ropes go through a sophisticated transformation process.

This is not to say the transformation is impossible, nor is it uneconomical. On the contrary, engineering innovations mean high volumes of clean FE material can be extracted for smelting and the residual material can be utilised in energy generation projects, as either an SRF or an even more refined pyrolysis solution.

The greatest challenge here is that many operators simply do not know what is possible.

Several years ago, for example, a paper mill on the European continent used to send 10,000 tonnes of pure, untreated pulper rope waste (1:3 metal and plastic) for specialist off-site handling. However, with a strong sustainability agenda, the business wanted to close the loop and harness the resource potential of this waste stream, in its own facility – while benefitting financially in the process.

Here, an UNTHA XR3000C – again with a high torque gearbox and two cutting rows, with auto-reverse function to help manage material flow – tackles this difficult application. The shredded fraction exits the machine via an enclosed horizontal conveyor with internal and external scrapers for easy cleaning, before travelling to an electro-magnetic FE separator. Metal wiring is consequently extracted for onward sale and recycling, with the resulting material forming the ideal SRF specification for the mill’s own WtE generation technology. It could of course be sold to an external alternative fuel offtaker too, which would represent an additional revenue stream for the pulper rope handler.

Resilient technology is required for pulper rope processing as no two grabs of pulper ropes are ever the same – input material homogeneity is therefore unlikely. However, dewatering would simplify the process somewhat, as would pre-cutting the ropes down to a <3m length.

At the time of implementation, this shredder was configured to achieve throughputs of 5 tonnes per hour, to meet the requirements of this facility. The commissioning of a pulper rope processing line is currently underway elsewhere in Europe, with the ability to handle 10 tonnes per hour and generate circa £200 per tonne revenue yield.

The exact technology required per mill, will depend on the number of pulping lines generating tails and the economics of the project concerned. Talking about what is possible – as well as the likely payback period – is key.