Expert workshop on
Biomass Combustion Generated Nanoparticles
Tuesday 14 June
This workshop took place as part of the 20th Nanoparticles
ETH, Zürich, Switzerland
BACKGROUND AND AIMS
Fireplaces and wood log stoves that
burn wood in a suboptimal manner are an important source of particle
emissions around the world. By phasing out polluting woodstoves and introducing
better stoves, improving stove installations and educating stove users,
large emission reductions can be achieved. Moreover, there is evidence
that the health impacts of fine particles from well operated biomass
combustion devices is much less harmful than that of suboptimally
operated devices.As biomass heating consitutes an important option to
contribute to renewable energy production in many countries, it is
important to recognise the differences in environmental impacts and
societal consequences for different types of combustion systems, and
take appropriate policy measures.
This T32 organised expert workshop on
biomass combustion generated particles took place on
14 June 2016 as integral part of the 20th Conference on Combustion Generated
Nanaoparticles . See
http://nanoparticles.ch for more information
and the other presentations offered at the conference.
The workshop showed that there is an
enormous difference in the relevance of biomass combustion particles
between well designed and operated stoves and boilers on the one hand,
and inappropriately designed or used devices. While in a modern and
automatically operated biomass boiler with state of the art flue gas
cleaning, particle formation may be primarly in the form of inorganic
components, which are then also almost fully captured in an
electrostatic precitpitator or baghouse filter, older biomass stoves and
boilers that do not avail of proper flue gas cleaning devices and are
inappropriately used, may cause significant particle emissions with also
All presentations of the workshop are available below.
An easily readible summary of the
workshop, published by the Swiss Federal Office of Energy, is available
POLICY STATEMENT ON THE NEED FOR REDUCTION OF PARTICLE EMISSIONS
Based on the results of the workshop,
Task 32 released the following statement.
Biomass is used as a renewable energy carrier to substitute fossil fuels for heat and power production.
Modern biomass boilers that comply with today’s emission limits and that are operated
appropriately have typically a low environmental impact. Biomass can therefore be used in an
environmentally friendly way, if the necessary requirements are met. There are, however, undesired
situations which can lead to non-ideal conditions.
This can potentially cause a high negative impact to the air quality
with an increased contribution to volatile organic compounds (VOC) and
inhalable particulate matter in the size range smaller than 10
micrometres (PM10) in the ambient air.
activities of various research groups represented in the International
Energy Agency (IEA) Bioenergy Task 32 and at the ETH Conference on
Combustion Generated Nanoparticles in June 2016 [1–5] it is concluded,
that the following topics need to be supported to avoid a high impact of
biomass combustion to ambient air quality:
The operation of the combustion devices has a strong influence on the
air pollutant emissions. This is true for all devices, however most
relevant for manually operated boilers and stoves. One important
issue is the use of an appropriate fuel with respect to fuel
moisture, size, and ash content for the dedicated combustion device.
Furthermore, an appropriate ignition is required. Investigations
show that an “ignition from the top” is favourable for many
conventional wood stoves. In addition, the amount of wood for one
batch needs to be adjusted to the size of the combustion chamber.
Finally, sufficient combustion air, although not exceeding a
reasonable amount, needs to be supplied during the combustion phase.
Standardisation of biomass fuels, combustion devices, type-tests,
and measurement technologies can assist a target-oriented
development to further improve the quality of biomass combustion
applications and ensure a low impact on air quality. For the
definition of new standards, test conditions which represent a
real-life operation should be considered.
guidelines and quality management for the planning and
implementation of biomass combustion plants can assist an
appropriate layout and dimensioning as a pre-condition for an ideal
operation of the combustion and the flue gas cleaning. Furthermore,
plant monitoring can assist an on-going optimisation of the
operation mode and an adaptation on varying requirements and fuel
international exchange of experience between all stakeholders from
research, industry, energy economics, and national authorities can
assist this process. Nevertheless, the enforcement of regulations on
energy standards and on air quality plays an important role and
needs to be followed also on a national basis.
The above statement can be downloaded as a separate PDF document