BT YOUNG SCIENTIST AND TECHNOLOGY EXHIBITION
“ Your boiler is set to have a fixed air to pellet ratio,” said Shauna,“ and when that is incorrect lots of gases are produced. Those gases are corrosive to metal, and they can be bad for the environment as well.” So, not alone is burning less efficient, but the boiler itself is likely to suffer.
Shauna carried out some tests, comparing performance of her own home boiler to those of a neighbour.“ The average boiler runs at about 75 per cent efficiency,” she said.“ The boiler next door was running at 73 per cent efficency without a filter, while ours was running at about 89 per cent efficiency,” This meant that there was an enormous difference of over 15 per cent in performance from the same fuel. In addition, carbon monoxide emissions were decreased by about 60 per cent.
Laundered diesel
ThErE is a big price difference between diesel for use on the farm and diesel for use on the road, yet the fuel is almost exactly the same. Farmers do not have to pay a hefty tax, so to prevent road users from tanking up with the cheaper fuel a dye is used, green in the republic and red in Northern Ireland. Not surprisingly, this has led to a black market for“ laundered” diesel. When the dye is removed the fuel looks normal enough for unsuspecting motorists to pay the full price.
What they do not see is the by-product of laundering, a dirty sludge that the criminal gangs engaged in this trade simply dump by the roadside. Giant industrial sized containers filled with sludge are a common sight by border county roadsides, and as Marlena Drobniewska, a fourth year student at Balbriggan Community College explained, local authorities are being forced to pay for expensive clean-ups. Because the sludge is an environmental hazard it has to be collected and exported for treatment and disposal. The cost to Louth County Council alone, where 90 sludge finds were made in 2011, is about € 1million a year.
When their science teacher, Tom O’ Donoghue, brought up the subject, Marlena and two of her class mates, ross McGrath and Cian holland agreed that looking at what could be done with the sludge would make a great Young Scientist project.
Ross McGrath, Marlena Drobniewska and Cian Holland at the RDS.
Another aspect of the problem, she added, is that the dust itself can be a hazard. Fine dust mixed with air can be explosive, and in industry great care has to be taken to avoid electrical sparks in enclosed spaces where dust is likely to occur. If wood pellet boilers were in an industrial setting, said Shauna, these precautions would be in place, and this is another good reason why filtering out the dust is so important with domestic boilers.
Shauna calculated that about 14 per cent of the fuel delivery is lost as dust, and again, Shauna gave this some practical thought.“ I put the dust in old milk cartons. In a stove or open fire, they burn perfectly.” That made her wonder if the dust could be recycled, but as she remarked,“ to make them into pellets or logs, you could need a powerful
As Marlena explained, the marked diesel is treated with bentonite, a mineral familiar to many people as an absorbent cat litter. Mixed with sulphuric acid the bentonite draws out the dye, and this becomes the sludge that no one wants.
At least, that’ s how the situation is now, but as the young scientists argue, that sludge could us used as fuel, and this is what they set out to do.
On its own, explained, Marlena, the sludge will burn, but not very well. Mixed with sawdust or cornflower, performance improves, and to show how the students conducted a series of tests. Five grams of the pure sludge was observed to burn for 376 seconds. Eighty per cent sludge with twenty per cent cornflower burned for 580 seconds, while raising the cornflower percentage to forty percent made the mix burn for 602 seconds. Beyond that, increasing compressor, and you would also need a bonding agent.”
Shauna thought it would be a good idea to patent her idea, but, with some wry amusement, she remarked that filtering out the dust is so easy that everyone can do it. Even so, Shauna is well on her way to becoming quite an expert in this field, and she is certainly not short of ideas.
The future of wood fuel is bright, and Shauna remarked that the obligation to meet energy targets is helping to push up demand. By 2020 forty per cent of Ireland’ s energy needs are to come from renewable sources, such as wood.( TK)
This report first appeared on the local forestry site www. forestgrowers. com
the percentage of cornflower led to a decrease in burn time.
The same tests were run using sawdust instead of cornflower, but the results were not as good.
The students made mini-briquettes from the mix, and given that the sludge is an environmental hazard, they were pleasantly surprised to learn from the Environmental Protection Agency that burning their briquettes would pose no problem.
As Marlena observed, cornflower is not expensive, and even if it is a cost, it would be a lot cheaper than having to export thousands of litres of hazardous waste.
The students got a helpful response from the EPA, but so far, said Marlena, no word back from the local authorities.“ Maybe they just didn’ t want to deal with a bunch of students,” she remarked with a shrug.
( TK)