Sustainable production 18 October 2013
Sustainable manufacturing is great in principle but much harder to achieve in practice. Brian Tinham looks at what engineers and managers can do today to make a difference.
Sustainability, the buzzword for the 21st century: easy for most of us to say, but difficult to get started and, well, sustain. That's in part because it is potentially so all-encompassing that companies don't know what to prioritise. But it's also due to the requirement for some serious re-education.
So, where to begin? Some will advise reviewing your site's energy consumption and looking for opportunities to cut back. This is the now classic green factory agenda, and we might bracket the use of VSDs (variable speed drives), efficient motors etc in such a drive. Aside from the usual capital cost, business case and payback hurdles, it should be fairly plain sailing, with the proof of the first project easing the pathway to the next, and improvements clearly sustainable.
Then there's materials themselves – production and non – and waste streams. Two separate, but potentially linked aspects for re-engineering and sustainability here, generally involving far longer projects, with many more people and departments. For the former, it's typically a matter of rethinking supply chains and ideally seeking out opportunities for closed loops, along the lines of the DEFRA's (Department for Environment Food and Rural Affairs) long-running WRAP (Waste and Resource Action Programme). That, as the name suggests, covers waste, too – and you'll find a growing cabal of consultants, such as Ricardo AEA, happy to offer advice.
But for your waste, it's also specifically worth considering alternative methods of disposal, treatment and re-use, while minimising costly and environmentally unfriendly transportation. If there's a possibility of, for example, engaging AD (anaerobic digestion), leading to CHP (combined heat and power), then you're building a project that takes sustainability to a more holistic level.
And, with landfill taxes due to increase again next year, you'll be positively impacting the bottom line in several ways. As Mark Penny, commercial manager with specialist J&B Recycling, says: "Currently, the levy stands at £72 per tonne, but with uncertainty over the government's direction once the escalator ends in 2014, business owners and managers need to think creatively about their waste streams."
Taking it from the top, MRO (maintenance, repair and overhaul) specialist Eriks is good value with the green factory. Its latest Planet+ initiative aims to focus engineers and managers on innovations that specifically 'reduce energy consumption, waste and pollution while protecting people, business and the environment'. And, as the firm's David Manning-Ohren suggests, that's certainly not just about VSDs and motors, important though these are.
Pointing, appropriately enough, to waste handling plants, he emphasises the importance of specifying everything from gearboxes to drive motors, couplings and chains with the sustainability agenda at front of mind. On the one hand, he says, that means taking advantage of the "remarkable achievements made in increasing the efficiency of such components". But on the other, it means taking into account the extreme loads, shock and contamination from dust, debris and glass as well as widely varying temperatures and, in many instances, infrequent maintenance that are bound to be features of such operations.
"Energy efficiency is by far the cheapest way of addressing any organisation's energy security and supply issues, but such measures are often ignored because they seem to have a longer payback period than can be justified," he asserts. "The truth, however, is that upgrading components such as gearboxes and drives can create huge savings. Identifying areas where equipment can profitably be replaced with the latest, more efficient versions, can increase both performance and efficiency. What's more, such equipment often qualifies for 100% tax relief under the Enhanced Capital Allowance scheme."
Moving on to greening materials and waste, Dr Adam Read, director of Harwell-based Ricardo AEA's waste management and efficiency business unit (which has its roots in the government's best practice programmes of the 1980s), says companies generally need help. "We typically go down their supply chains and see what materials they're using, where they come from, how they're processed and the outputs. Then we look for the savings. Do they have recycling onsite? Are there opportunities for pallets to be reused on the backhaul to close the loop? Are they using the right raw materials?"
He gives the example of lithium, as used in Li-Ion batteries, which is seeing reserves rapidly declining. "How closely do they understand what's happening? We'll raise awareness of resource risk and challenge them to consider ways to mitigate that by moving to sustainable sourcing and recycling."
Read concedes that such projects are easier with non-production supply chains than production. He suggests the best approach is to start with the quick wins such as instituting sustainable and ethical procurement with new KPIs that can cascade that down the supply chain and drive change. "When it comes to production, they may have invested in new equipment a few years ago, which has since been superseded. So they could get, say, 10% more productivity, but the upgrade might cost half a million pounds. Our job is to help them with the business case and get over the 'it's not broken so we're not replacing it' argument by looking at their machines' remaining lifecycle risks, the quality and price trajectory of source materials competitive issues etc."
It's a similar story with waste streams. The approach is to seek out financially rewarding and sustainable opportunities to recycle and treat waste on- or near-site. And the rewards: reduced disposal costs, but, significantly, also the potential to generate heat and power for production processes using, for example, AD.
That's far from fanciful. Acquiring such plant is now easier than ever with, for example, the likes of renewable energy specialist ENER-G now offering outsourced AD and CHP services, including design, installation and operation. Because ENER-G finances the project, there are no upfront costs or financial risk: the company simply recovers its investment by sharing savings over a contract period.
Scott Tamplin, director of AD development at ENER-G, says users can expect to receive 20—50% of the annual savings, through renewable heat and electricity. "This type of combined waste management and energy efficiency system immediately reduces the user's energy costs and carbon footprint," he insists. And he adds that the AD process can reduce the COD (chemical oxygen demand) content of effluent by 80—95%, so dramatically reducing effluent costs and offering potential for water recycling, once solids are removed.
Incidentally, if you're thinking: 'Ah, yes, but not our waste,' AD is not the only game in town. Green technology specialist DPS Global is now offering what it describes as a compact, commercial and sustainable energy-from-waste solution that turns even clinical and hazardous waste into heat and power. James Sessions-Hodge, the company's environmental technology manager, explains that its plant – a development of a DEFRA-funded demonstrator project at Avonmouth more than a decade ago – involves staged pyrolysis and gasification of difficult waste, with the outputs being some ash, but also energy for CHP.
In operation, waste is fed into a tube that is externally heated by exhaust gases from later stages of the process to achieve pyrolysis (thermal decomposition of organic material through heat alone). That produces syngas (synthetic gas), which is augmented by gasification of remaining char and burnt with a controlled quantity of air to reach 1,150°C to destroy any carried-over pollutants.
"Our technology is the first economically-viable, small-scale unit to separate the carbon and hydrogen fuel we need from the rest of the waste, while trapping pollutants [hitherto released to atmosphere in traditional incinerators] in ash from the process, which is typically just 5—10% of the original waste," says Sessions-Hodge. "This enables hospitals, commercial operations and industrial plants to use their waste as a substitute for fossil fuels, thereby reducing CO2 emissions and heating bills by as much as £100,000 per annum, dependent on feed volumes," he adds.
This matters. As Dr Read puts it: "We mustn't fear rising production and fuel costs or resource scarcity. There are plenty of opportunities to reengineer our businesses and save money. We could probably save you 4—5% of operating costs from our first visit. It's all about rethinking what you do, the payback and managing behavioural change. Either way, we need to recognise that change is coming, especially around recycling and reprocessing, and we need to deal with that. In 10 years from now the UK will effectively be a re-manufacturing economy, not a manufacturing economy."
Eriks Distribution & Engineering
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