The changing face of fuel preparation
Expansion of a niche market
There was a time when the production of energy sources such as Solid Recovered Fuel (SRF) was something considered only by market leaders – those with vast budgets to invest or a particularly transparent environmental agenda to drive.
But the benefits of Waste to Energy (WtE) soon became more widely understood, not least because of the feedstock security and control that comes with cement operators manufacturing their own fuels. As a result, more and more co-processing facilities have been built globally over the years, and a growing number of waste firms have entered this somewhat niche space, aware of the market potential that exists.
Alongside this industry evolution, it perhaps comes as no surprise that the fuel manufacturing process itself has not stood still. Such advancements are common with the development of any market. As global knowledge matures, technological innovation continues apace and trade opportunities increase, so too do the expectations placed on operators and the processes they adopt.
Evolving alternative fuel production priorities
In the beginning throughput was the primary consideration when commissioning alternative fuel production plants, and understandably so. It was seen as the answer to any investment payback – surely more product yield would mean greater ROI.
Then SRF quality appeared on the radar, with operators demanding that systems deliver fuel on time and to the required specification. The more defined the fuel in terms of particle homogeneity and calorific value, the greater the burn efficiency and the more attractive the output product as an energy source.
Flexibility even became important – could the alternative fuel production line handle more than one type of input material for instance, according to the changing market/supply and demand? If so, it would certainly minimise commercial risk and protect the financial viability of the facility.
In 2020 and beyond..?
However, this didn’t mean, as a sector, that all opportunities were exhausted when it came to the efficient manufacturing of calciner and main burner fuels. Innovation has continued to take place on a global scale, because with experience comes insight. And this is when things get really exciting.
Over time operators have begun to think less about the aforementioned points in isolation, in favour of building extremely sophisticated plants capable of achieving all of these criteria and so much more.
Throughputs are now no longer evaluated on the basis of singular factors such as machine speed for instance, but for the true overall capacity of a facility. SRF manufacturing lines are therefore now being designed with whole equipment uptime and availability in mind. In 2020 and beyond, everything from the loading aperture of waste shredders, to quick and easy maintenance regimes, robust high torque drives, and foreign object protection systems that could prevent unplanned outages, will all underpin a plant’s technology requirements, as standard.
Even seemingly sophisticated quality-led considerations have evolved further still, because a more refined fuel doesn’t just benefit the cement kiln concerned, but the environment too. Better material segregation and the extraction of valuable metals and other recyclates means greater adherence to the waste hierarchy, and therefore the more environmentally gainful utilisation of resources in line with regulatory guidance. The sale of recyclates should also boost the revenue generating potential of the plant, as there’s the opportunity to not just avoid disposal costs but kickstart an additional income stream too.
In terms of flexibility, this is no longer evaluated purely in terms of the input materials a plant can handle. Now, operators want to be able to process a range of ‘wastes’ with just a quick and easy shredder reconfiguration – downtime costs money after all. Operators have also quite rightly begun to seek machines that can satisfy various output requirements too, with different particle sizing, bulk density and calorific value demands set for different types of fuel.
Evolving efficiency expectations
The industry was right to strive for more, because which successful business environment ever stands still? And the benefits have been plentiful.
Operators who have invested in savvy SRF production facilities are now experiencing reduced energy consumption, improved uptime, more yield and lower operational costs per tonne, which means their margins are maximised as a result. The net environmental efficacy of the manufacturing process is also heightened as the carbon impact of such facilities is far less.
UK-based Lancashire Waste Recycling offers an interesting case in point in this respect. The SRF specialist has been making a high-specification fuel at its Fleetwood site since the business was established in 2013. However, the firm recently announced that it has halved plant wear costs and further boosted its manufacturing capacity with an investment in its sixth UNTHA shredder.
When Lancashire Waste’s SRF journey began, an UNTHA XR2000 pre-shredder fed two TR3200s secondary shredders, to produce a renewable energy source for the cement industry.
But as engineering innovation continued – to challenge the industry norm of high speed SRF manufacturing – the client worked with UNTHA’s UK division to understand how to leverage the potential that next-generation technology could bring.
When Lancashire Waste opened its second SRF production plant 46 miles away in Burnley, a single UNTHA XR3000C was installed at its heart. This slower speed equipment could produce a quality 40mm fuel in a single pass, without the concerns surrounding downtime or damage when higher speed machines encounter unshreddable items.
Fast forward to 2019, and the growing company wanted to further strengthen its alternative fuel production capabilities. Advanced trials with UNTHA ensued and it became clear that the new UNTHA XR3000XC could achieve an on-specification 30mm particle with slightly more throughput than the two TRs combined.
The two Fleetwood post-shredders were consequently switched, so that the original XR2000 now feeds the XR3000C and the new 85rpm XR3000XC machine. A capacity of 30tph has been achieved as a result.
A 65rpm XR3000XC has also been added to the Burnley line to take hourly throughputs on this site to 20tph.
Commenting on the new fleet of state-of-the-art technology, Lancashire Waste’s founder Jim Entwistle said: “As a business, we’re constantly looking to progress, so consistency and capacity are key to our operation. We work with three UK cement kilns and one export offtaker, and the better quality the fuel, the more our clients seek. We’ve doubled our supply to one kiln, for example, over the past 18 months, so the impact on our business – from savvier waste shredding – is vast.
“Add to this 40% less energy costs, halved wear costs and only minimal damage repairs as we’ve moved away from high speed machines, and the business case for our shredder investment is extremely strong.”
Whereas ‘single step SRF shredding’ was once the industry’s go to term, this heightened plant efficiency – by design – is now being increasingly referred to as ‘quick SRF’. Key features of quick SRF systems include flat blade cutters, simpler machine design with less wear components, rotor speeds of 65-85 rpm (compared to 250-350 rpm), even greater resistance to unshreddables, downtime of minutes not days thanks to more forgiving clutches, and the option for mobile equipment that provides machine movability where required.
Quick SRF operators also typically think about setting their technologies up as complete turnkey systems, rather than considering individual machines in a piecemeal manner. Engineering benefits are usually experienced throughout an entire plant, not just one piece of equipment, as a result of this holistic approach.
SRF still not a panacea
This isn’t to say that SRF is a panacea of course. A more environmentally sound scenario would naturally be to avoid the creation of commercial and industrial, municipal, production, construction and demolition waste materials in the first place.
However, for as long as such ‘trash’ continues to be produced worldwide, it is important to devise considered ways to deal with these arisings. SRF offers a suitable solution in this respect, especially when the ‘green’ benefits – not to mention the financial rewards – can be boosted.