* Corresponding author:
Therese Schwarzboeck
email: therese.schwarzboeck@tuwien.ac.at
Detritus / Volume 02 - 2018 / pages 120-132
https://doi.org/10.31025/2611-4135/2018.13649
© 2018 Cisa Publisher. Open access article under CC BY-NC-ND license
DETERMINING THE CLIMATE RELEVANCE OF REFUSE-DERIVED
FUELS - VALIDITY OF LITERATURE-DERIVED VALUES IN
COMPARISON TO ANALYSIS-DERIVED VALUES
Therese Schwarzboeck
1
, Philipp Aschenbrenner
1
, Sarah Muehlbacher
1
, Soenke Szidat
2
,
Stefan Spacek
1
and Johann Fellner
1
1
Institute for Water Quality and Resource Management, TU Wien, Karlsplatz 13, 1040 Vienna, Austria
2
Laboratory for the Analysis of Radiocarbon with AMS (LARA), Department of Chemistry and Biochemistry & Oeschger Centre for
Climate Change Research, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
1. INTRODUCTION
Within the European Union, in 2012 already 34% of pri-
mary energy carriers in cement kilns are substituted by
mixed wastes and refuse-derived fuels (RDF). In Austria an
average substitution rate of 75% is reported (VÖZ, 2015).
The utilization of alternative fuels in energy-intensive in-
dustry branches is a means to reduce the exploitation of
natural resources, reduce costs and to lower fossil carbon
dioxide emissions (Aranda Usón et al., 2013; Pomberger
and Sarc, 2014). For the appraisal on the fossil CO
2
-savings
(and therewith connected economic savings for emission
certifcates), it is required to know on the one hand the car-
bon content originating from materials of fossil origin in
the RDF and on the other hand the overall calorifc value
of the RDF. Both depend, among others (e.g., water con-
tent), on the shares of fossil and of biogenic materials. In
solid RDFs fossil materials comprise mainly plastics and
synthetic textiles; biogenic materials could be paper, natu-
ral fbers, wood, etc. The shares of the compounds in sol-
id RDFs are usually not known and may vary signifcantly
depending on the material used for RDF production. The
material used is usually pre-treated municipal solid waste
(MSW), commercial waste (CW) and industrial waste (IW).
The composition thus, strongly depends on the input ma-
terial and hence, on the collection and sorting schemes,
and also on local industries. Further, the shares of fossil
and biogenic materials present in the RDF are decided by
ABSTRACT
The adapted Balance Method (aBM) represents a cost effcient method for deter-
mining the fossil share in solid refuse-derived fuels (RDF). The method requires data
on the elemental composition of the RDF on water-and-ash-free basis (TOX
RDF
) and
on the elemental composition of biogenic and fossil organic matter on water-and-
ash-free basis present in the RDF (TOX
Bio
and TOX
Fos
). TOX
Bio
and TOX
Fos
generally
need to be defned only once (e.g., before a routine application). After these data
are known, only TOX
RDF
needs to be determined analytically for any RDF sample in
order to apply the aBM. As TOX
Bio
and TOX
Fos
are crucial input parameter for the aBM,
the presented paper aims to assess the most suitable and practical way for their
reliable determination. Within this study, 6 different solid RDFs are investigated and
the aBM is applied, whereby the suitability of literature values is compared to own
analysis data for TOX
Bio
and TOX
Fos
. The potential utilization of literature data could
save the initial workload when applying the aBM and could make the method even
more economical and practical compared to other methods. Altogether, seven aBM
results are compared utilizing seven different methods for generating input values of
TOX
Bio
and TOX
Fos
: using generic values, literature values only, analyses results only,
or combinations of literature and analyses data. The study results suggest that the
usage of analysis data together with information from literature is the best option
to derive reliable input data (TOX
Bio
and TOX
Fos
) for the aBM (mean deviation from
standardized methods of below 2%). The fndings further suggest that there is a typ-
ical composition of the biogenic and fossil organic matter present in RDFs produced
out of commercial and industrial waste. Thus, the initial workload for conducting
RDF-specifc analyses could be signifcantly reduced when some more data about
different types of RDFs are collected (e.g in a database).
Article Info:
Received:
23 January 2018
Revised:
15 May 2018
Accepted:
25 June 2018
Available online:
30 June 2018
Keywords:
Refuse derived fuels
Balance method
Biomass content
Fossil carbon
Elemental composition
Manual sorting