Engineered Systems - February 2008 - (Page 29) Tighter air regulations and and abundance of trees have paired up to fuel the move toward hybrid biomass boilers in these Canadian hospitals. Read about the upgraded systems’ differences and the considerations for trading fossil fuels for sawdust, wood chips, and bark. BY JOANNA R. TURPIN T hink of Canada, and there’s a good chance that what comes to mind is a sparsely populated country with spectacular scenery. Meandering coastlines, dramatic mountain ranges, and pristine lakes are located throughout the provinces, as well as vast expanses of forest, which carpet 402 million hectares — or almost half — of the country. Given the enormous amount of trees growing in Canada, it is no wonder that the forest industry is extremely important to the country’s economy. It contributes up to 3% of the gross domestic product and over $34 billion in exports, which include the largest amount of market pulp and newsprint in the world. The province of Quebec is an integral part of the country’s forest industry, as its millions of acres of forests supply approximately 500 mills with wood for lumber, pulp and paper, and plywood. These mills process countless numbers of trees every day, resulting in massive quantities of byproducts such as sawdust, bark, and wood shavings. The mills would normally have to pay to have these byproducts removed from their sites, but two Quebec hospitals are now utilizing the wood waste to power their new biomass boilers. REDUCED EMISSIONS Canada has often been in the forefront of environmental legislation, and continued actions by the government support that position. The government recently introduced tough, mandatory regulations for industry to reduce greenhouse gas emissions by 20% by 2020 and 60% to 70% by 2050. The government also plans to cut air pollution in half by 2015, which is the most aggressive plan in Canadian history. In order to curb its greenhouse gas emissions and comply with the regulations, the government of Quebec asked the mechanical contracting firm of R. Nantel & Associés Inc., Montreal, to survey its northern hospitals to determine if they were candidates for biomass boilers. “Years ago, the government purchased solid fuel boilers, which today are in such bad shape, there was no way to get them legal with the environment, so they had to be replaced. There are a lot of sawmills in northern Quebec that have a lot of solid fuel left all over the place that the hospitals could use, so the biomass boilers made sense,” said Roland Fauteux, of R. Nantel & Associés Inc. These boilers not only utilize the wood waste from the local mills, they also substantially improve the hospitals’ energy efficiency while reducing the facilities’ emissions of greenhouse gases. Some might question whether or not burning wood is that much cleaner than burning other types of fuel (Sidebar), but modern biomass boilers come equipped with proven emissions control devices that significantly reduce NOx and CO emissions. In addition, particulate emissions are reduced through the use of cyclone separators, bag houses, or electronic precipitators, which catch almost all the ash generated during the combustion process. Two small hospitals in northern Quebec, La Sarre and Macamic, were just recently retrofitted with new biomass boilers, and there are more on the horizon. “There are close to 11 hospitals to do,” said Fauteux. “Usually after one is done, the start-up completed, and the bugs worked out, we go on to the next one. We do one a year, because by the time the operators are at ease, it takes that much time. It also comes down to budget, because there’s only so much money to spend.” And, as Fauteux pointed out, once he gets into the boiler room, there’s more to do than just replace the boiler: Most of the other equipment needs to be repaired or replaced as well, including headers, valves, pumps, and heat exchangers. Fauteux noted at one hospital, one of the high-pressure valves had a hole in it, and a screw had been put in to hold the steam. “You definitely didn’t want to go alongside where the screw was,” he chuckled. “You’d get a hole in your head if it let go.” w w w. esmag a zin e. c o m 29 http://www.esmagazine.com
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