CESI - Emission factors of domestic and centralized boilers: preliminary results - Report for EGTEI (2007)
Based on A5028867 “Risultati preliminari delle prove di valutazione dei fattori di emissione da caldaie domestiche e centralizzate.”

Options for limit values for emissions of dust from small combustion installations < 50 MWth – Prepared for the Swiss Federal office of Environment as a contribution for EGTEI - June 2010

Small combustion installations are important sources of particulate emissions. However this source category was not yet included in the draft technical annexes to the revised Gothenburg Protocol. At its 45th session, the Working Group on Strategies and Review (WGSR) therefore invited the Expert Group on Techno-economic Issues (EGTEI) to explore the possibility of establishing emission limit values (ELVs) for dust for small combustion installations (SCI), i.e. installations with a thermal input < 50 MW, with a special focus on wood combustion. At its 16th meeting EGTEI has delegated this task to a newly designated subgroup on SCI.

According to the terminology defined in the draft technical annexes to the revised Gothenburg protocol as adopted by EGTEI for other source categories, options for emission limit values (ELV) have been defined in a three tier approach:

  • Option 1: ELV1 is a demanding but technically feasible option with the objective of achieving a high level of reduction. The ELV1 is based on a value between the lower and upper BAT AEL (where it is available),
  • Option 2: ELV2, while technically demanding, pays greater attention to the costs of the measures for achieving reduction. The ELV2 is a value based on the upper BAT AEL (where it is available),
  • Option 3: ELV3 represents current good practice is based on the legislation of a number of Parties to the Convention.

Since no official BAT reference documents (BREF) have been published so far for SCI, information on best practice and achievable emission levels has been compiled in a technical background report.

The Gothenburg protocol amended in 2012, includes ELVs resulting from a consultation process of stakeholders based on the document prepared.

Thomas Nussbaumer - Overview on Technologies for Biomass Combustion and Emission Levels of Particulate Matter - Prepared for the Swiss Federal office of Environment as a contribution for EGTEI - June 2010

Since small combustion installations are an important source of PM, the Working Group on Strategies and Review (WGSR) in the UNECE Convention on Long-range Transboundary Air Pollution (CLTRAP) invited the Expert Group on Techno-economic Issues (EGTEI) to explore the possibility of establishing emission limit values for PM for combustion installations with a thermal input smaller than 50 MW. The present report was prepared as a technical background for the definition of emission limit values by the EGTEI with focus on biomass combustion. The fundamentals of wood combustion chemistry are described to introduce the mechanisms of particle formation. From this, three different particle types are distinguished, i.e., soot, salts, and condensable organic compounds.

Depending on furnace type and combustion regime, one or more of these particle types are emitted in high concentrations and thus need to be reduced by different measures according to the formation mechanisms. For residential wood combustion, primary measures to improve the burnout quality are crucial, while for automatic wood combustion plants, inorganic particles need to be reduced by secondary measures. The technologies for residential and industrial scale biomass combustion are described including primary measures to improve the combustion quality by a two-stage combustion, which enables a high combustion temperature and a good mixing between combustible gases and air to reduce products of incomplete combustion. In addition, secondary measures for PM abatement such as electrostatic precipitators and fabric filters are described and their effects on cost are discussed.

Finally, PM emission factors and achievable PM emission levels are compared and the influence of the measurement method for PM is discussed.