VGB POWERTECH 10 (2020) - International Journal for Generation and Storage of Electricity and Heat

Implementation of Basic Requirement in harmonized product standards VGB PowerTech 10 l 2020
[9] CEN/TS 16637-1: Construction products –
Assessment of release of dangerous substances
– Part 1: Guidance for the determination
of leaching tests and additional testing step
(2014).
[10] CEN/TS 16637-2: Construction products –
Assessment of release of dangerous substances
– Part 2: Horizontal dynamic surface
leaching test (2014).
[11] CEN/TS 16637-3: Construction products –
Assessment of release of dangerous substances
– Part 3: Horizontal up-flow percolation
test (2016).
[12] FprCEN/TS 17216: Construction products:
Assessment of release of dangerous substances
– Determination of activity concentrations
of radium-226, thorium-232 and potassium-40
in construction products using
gamma-ray spectrometry (2018).
[13] CEN/TR 17113: Construction products. Assessment
of release of dangerous substances.
Radiation from construction products. Dose
assessment of emitted gamma radiation
(2018).
[14] EN 450-1: 2012 Fly ash for concrete – Part
1: Definitions, specifications and conformity
criteria.
[15] CENT C 104/WG 4: Background report on
existing environmental regulations for fly
ash for concrete, doc160-2016, updated
doc212 (status 06.2020), WG 4 internal
document.
[16] VV-TB/ABuG: Administrative Provision –
Technical Building Rules (VVTB) and Requirements
on constructions regarding impact
on soil and water (ABuG); https://
www.dibt.de/de/wir-bieten/technischebaubestimmungen/.
[17] DAfStb Richtlinie: Verwendung von siliziumreicher
Flugasche und Kesselsand in
Betonbauteilen in Kontakt mit Boden,
Grundwasser oder Niederschlag (Use of siliceous
fly ash and bottom ash in concrete
components in contact with soil, ground water
or rain), 2020.06 (in German language
only); available with.
[18] Soil Quality Decree, Rijkswaterstaat, Ministry
of Infrastructure and Environment
(http://rwsenvironment.eu/subjects/
soil/legislation-and/soil-quality-decree/).
[19] CEN TC 104/WG4: Discussion paper implementation
BWR3 in EN 450, doc 180/2017
(TC internal paper on CEN livelink). l
VGB-Book
Modelling primary NOx and primary N 2 O of Pulverised,
Fuel Combustion and Circulating Fluidised Bed Combustion
Frans van Dijen
VGB-B 015, 2018, DIN A5, 88 pages, Price € 91.59–, + VAT, ship ping
With more stringent emission limits with time, including NOx and N 2 O, and due
to the high costs of secondary measures for NOx emissions reduction, knowledge
of primary NOx and primary N 2 O is very important. With this knowledge, primary
NOx and primary N 2 O can be reduced at low costs and in this way costs for
secondary measures are much reduced as well. By applying the knowledge presented,
the project costs of a CFBC plant can be lower than those of a PFC plant.
Knowledge regarding primary NOx and primary N 2 O, and their models, is
useful for operators of PFC and CFBC regarding the influence of (the change of):
––
Fuel, with PFC and CFBC; Lambda, with PFC and CFBC; Temperature, with CFBC;
Addition of limestone to the bed, with CFBC.
Knowledge regarding primary NOx and primary N 2 O, and their models, is useful for suppliers of boilers,
burners, etcetera, regarding the influence of (the change of):
––
Design, with PFC and CFBC; Fuels and fuel flexibility, with PFC and CFBC; Conversion of the boiler for other fuels,
with PFC and CFBC; Developing assisting systems/software, with PFC and CFBC; Temperature, with CFBC;
Addition of limestone to the bed, with CFBC.
With this thesis, the mathematical models of primary NOx of CFBC, primary NOx of PFC and primary N 2 O of
CFBC were improved.
A model regarding PFC was made. This model is based on: the furnace, the specific N-content of the fuel, the
fuel ratio FR and the air-to-fuel ratio Lambda. The models regarding CFBC are based on: the furnace, the specific
N-content of the fuel, the fuel ratio FR, the combustion temperature and the air-to-fuel ratio Lambda.
From a qualitative point of view, the mathematical models of primary NOx are useful, both with PFC and CFBC.
From a quantitative point of view, the models of primary NOx with CFBC and PFC, and N2O with CFBC, are not
satisfactory. They hold for a specific boiler only. Primary emissions of NOx and N2O of CFBC also depend on air
staging, catalytic activity of the ash and/or bed material, the bed inventory, “limestone addition”, cyclone separation
efficiency, flue gas residence time, etcetera, which are not (yet) modelled. In this thesis attention is especially
paid to the CFBC design parameters cyclone separation efficiency, “limestone addition” and the height of the secondary
air ports above the bottom, and their influence on primary NOx and primary N2O.
With CFBC, the presence of catalytically active elements, like Na, K, Fe, Mg and Ca, in the fuel, the ash and the
bed material, must be considered as well, which is often not the case in literature. The addition of limestone to the
bed can increase primary NOx drastically, depending on the fuel, and hence in such cases limestone addition is
definitely a bad idea.
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Modelling primary
NOx and primary
N 2
O of Pulverised
Fuel Combustion and
Circulating Fluidised
Bed Combustion
Frans van Dijen
VGB-B 015
50