Artikkelit jotka sisältää sanan 'air pollution'
Turpeen pyrolyysistä.
English title: Pyrolysis of peat.
Avainsanat:
air pollution;
pyrolysis. peat
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The release of nitrogen and sulphur compounds in peat pyrolysis was investigated bet ween 300 and 700 °C. Seven peats with different nitrogen and sulphur contents (N: 0.8—2.9 %, S: 0.08—0.24 %) were studied. The pyrolysis was studied indirectly by following the elemental composition and the structure of the char residue. The tars of one peat sample were trapped.
The greatest portion of the sulphur-containing compounds pyrolysed below 500 °C. Nitrogen-containing compounds pyrolysed in a larger temperature range. One group of peats contained easily pyrolysable and the other group weakly pyrolysable nitrogen compounds. This suggests that the behaviour of fuel nitrogen in combustion will be difficult to predict because pyrolysis compounds may react further to corresponding oxides. The nitrogen content may be high in the tar in which case the tarry in termediates may also increase the amount of NO in flue gases. Infrared spectroscopy provided information about the decomposition of the main compounds in peat, like carbohydrates and long chained hydrocarbons during charring complementary to the information provided by elemental analyses.
Keywords: pyrolysis. peat, air pollution.
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Aho,
Technical Research Centre of Finland,Domestic Fuel Laboratory,P.O. BOX 221,SF-40101 Jyväskylä,Finland.
Sähköposti:
ei.tietoa@nn.oo
Sammalpallomenetelmä lyijysulaton päästöjen tutkimuksessa.
English title: Monitoring lead emissions with moss bags near a lead smelter in southern Finland.
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Moss (Sphagnum) bags were used to study the deposition of lead near a lead smelter in Vantaa, southern Finland, during 1983—1986. Pit-furnace and refining smelting were carried out. However, in March 1984 pit-furnace smelting ceased. The content of lead in moss bags increased clearly with decreasing distance from the source. The values were clearly smaller after the change in smelting process. Besides the moss bag method we also compared moss bags with other methods (deposition, suspended particles, snow sampling). There existed highly significant correlations between moss bag and other methods. The moss bag method enables a dense monitoring net and was found to be a rapid, easy and inexpensive way of monitoring the intensity and distribution of lead pollution.
Key words: lead, air pollution, monitoring, moss bags, Sphagnum.
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Vasander,
University of Helsinki, Department of Peatland Forestry, Unioninkatu 40 B, SF-00170 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
- Mikkola, Sähköposti: ei.tietoa@nn.oo
Puuta ja turvetta käyttävien lämpölaitosten päästöt.
English title: Emissions from wood and peat-fired heating plants.
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The use of wood and peat in small scale boilers (10 kW—10 MW), has increased because the price of oil has advanced. Further the acidification of environment caused by emissions of sulphur oxides has increased. Wood and peat with their small sulphur content are good fuels in this respect.
Emissions of sulphur dioxide, hydrocarbons and nitrogen oxides are not too high during good combustion process. If wood and peat is burnt in plants (1—10 MW), emissions of hydrocarbon and polynuclear aromatic hydrocarbons (PAH) are low. High emissions of tar, total hydrocarbon and PAH have been measured from combustion of wood and peat in small furnaces. The development of boilers to correspond better the properties of the fuels used may decrease significantly these emissions. Also the complete control of the whole combustion process helps to the emissions.
The dust emissions of small plants can be decreased with flue gas collectors. The multicyclone has generally been used as the collector in this scale. Emissions of some metals depend on the fly ash separation efficiency.
Key words: emissions, air pollution, wood firing, peat firing, combustion process.
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Vesterinen,
Technical Research Centre of Finland, Domestic Fuel Laboratory, P.O. Box 221, SF-40101 Jyväskylä, Finland
Sähköposti:
ei.tietoa@nn.oo
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