Title:
Evaluation of the Low-temperature Corrosion Potential of Flue Gases from the Combustion of Wood and Non-wood Fuels
Author(s):
Brunner, T., Obernberger, I., Ramerstorfer, C., Kanzian, W.
Document(s):
Paper
Abstract:
During recent years increased efforts have been taken to make biomass combustion technologies more fuel flexible. Especially in the medium and large capacity range but recently also in the residential heating sector the utilisation of fuel assortments other than classical wood fuels (pellets, wood chips, forest residues) opens a wide potential of different and also more cost efficient feedstocks to be utilised. Examples are wood from SRF and agricultural residues such as shells, olive stones, miscanthus and agro-pellets. These fuels often show elevated S and Cl contents. Related problems with HCl and SOx emissions can be overcome with state-of-the-art secondary emission control technologies such as dry sorption. However, the influence of the fuel composition, especially of the S and Cl contents, on low temperature corrosion phenomena such as acid dew point corrosion and corrosion due to deliquescent salts in economisers, filters and air pre-heaters is still not well investigated. Therefore, a series of lab-sale and full-scale combustion test runs with a broad range of biomass fuels under application of novel measurement methods and equipment has been performed in order to investigate the relation between the fuel composition and low-temperature corrosion risks. According to the results achieved, corrosion due to acid dew points plays a minor role for these fuels but deposits of hygroscopic salts such as KCl and K2CO3 may lead to dew points that are significantly higher than the water dew point and consequently to related corrosion risks. Based on these results recommendations regarding minimum surface temperatures to avoid low-temperature corrosion have been derived.
Keywords:
biomass, emissions, fly ashes, fuel flexibility, low temperature corrosion
Topic:
Biomass Conversion Technologies for Heating, Cooling and Electricity
Subtopic:
Biomass combustion in large utilities
Event:
26th European Biomass Conference and Exhibition
Session:
2AO.8.1
Pages:
430 - 439
ISBN:
978-88-89407-18-9
Paper DOI:
10.5071/26thEUBCE2018-2AO.8.1
Price:
FREE
