SIST-TS CEN/TS 15439:2009
(Main)Biomass gasification - Tar and particles in product gases - Sampling and analysis
Biomass gasification - Tar and particles in product gases - Sampling and analysis
This European Technical Specification gives methods for sampling and analysis of tars and particles in order to determine the load of these contaminants in flowing biomass gasification product gases. The Technical Specification is applicable to sampling and analysis of tars and particles in the concentration range typically from 1 mg/mn3 to 300 g/mn3 (tars) and from 20 mg/mn3 to 30 g/mn3 (particles) at all relevant sampling point conditions
(0 °C to 900°C and 60 kPa to 6000 kPa (0,6 bar to 60 bar) ) ), ). Particle concentrations lower than 20 mg/mn3 are outside the scope of this Technical Specification and can be measured according to EN 13284-1.
Application of this Technical Specification allows determination of five different parameters:
A. The concentration of gravimetric tar in mg/mn3;
B. The concentration of individual organic compounds in mg/mn3. This Technical Specification gives data on repeatability and reproducibility for the compounds listed in Annex B. The Technical Specification is also applicable for other organic compounds (e.g. those mentioned in Annex A), but repeatability and reproducibility have not been assessed for compounds other than those in Annex B;
C. The sum of concentrations of identified GC-detectable compounds listed in Annex B;
D. The sum of concentrations of all GC-detectable compounds with retention times in the range of benzene to coronene calculated as naphthalene (benzene excluded), given that this sum of concentrations can be determined.
E. The concentration of particles in mg/mn3.
Biomassevergasung - Teer und Staub in Produktgasen - Probenahme und analytische Bestimmung
Gazéification de biomasse - Goudron et particules dans les gaz produits - Échantillonnage et analyse
Uplinjanje biomase - Katran in delci v proizvodnih plinih - Vzorčenje in analiza
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TS CEN/TS 15439:2009
01-september-2009
8SOLQMDQMHELRPDVH.DWUDQLQGHOFLYSURL]YRGQLKSOLQLK9]RUþHQMHLQDQDOL]D
Biomass gasification - Tar and particles in product gases - Sampling and analysis
Biomassevergasung - Teer und Staub in Produktgasen - Probenahme und analytische
Bestimmung
Gazéification de biomasse - Goudron et particules dans les gaz produits -
Échantillonnage et analyse
Ta slovenski standard je istoveten z: CEN/TS 15439:2006
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
75.160.10 Trda goriva Solid fuels
SIST-TS CEN/TS 15439:2009 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TS CEN/TS 15439:2009
TECHNICAL SPECIFICATION
CEN/TS 15439
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
May 2006
ICS 13.040.40; 75.160.10
English Version
Biomass gasification - Tar and particles in product gases -
Sampling and analysis
Gazéification de biomasse - Goudron et particules dans les Biomassevergasung - Teer und Staub in Produktgasen -
gaz produits - Échantillonnage et analyse Probenahme und analytische Bestimmung
This Technical Specification (CEN/TS) was approved by CEN on 21 February 2006 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15439:2006: E
worldwide for CEN national Members.
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Contents Page
Foreword.3
Introduction.4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviations .8
5 Principle of the measurement method .8
5.1 Introduction.8
5.2 Sampling.8
5.3 Analysis .8
6 Reagents.9
6.1 Solvent for tar collection and Soxhlet extraction.9
6.2 Carrier gas in gas chromatography.9
6.3 Calibration standards.9
7 Equipment .9
7.1 Equipment for sampling.9
7.2 Equipment for sample pretreatment and analysis . 13
8 Preparation of sampling equipment . 13
8.1 Preconditioning of filter thimbles . 13
8.2 Cleaning of equipment . 14
8.3 Preparation of impinger bottles or Petersen column. 14
8.4 Sampling train leak test . 14
9 Procedure for sampling . 15
9.1 Introduction. 15
9.2 Duration of sampling. 15
9.3 Sampling procedure . 16
10 Storage of samples. 16
11 Preparation for analysis. 17
11.1 Introduction. 17
11.2 Requirements for GC calibration standards and internal standards (ISTD) . 17
12 Analysis procedures . 18
12.1 Soxhlet extraction procedure. 18
12.2 Combination of solvents. 19
12.3 Determination of particle mass . 19
12.4 Determination of gravimetric tar mass. 19
12.5 Determination of individual tar compounds by GC–MS or GC-FID. 20
13 Calculation of GC results. 21
14 Performance characteristics . 21
14.1 Introduction. 21
14.2 Performance of the analysis methods (Round Robin tests) . 22
14.3 Performance of the whole Technical Specification (parallel tests). 23
15 Test report . 24
Annex A (informative) List of most abundant individual organic compounds in biomass gasification
product gases . 25
Annex B (normative) List of organic compounds for which precision data have been collected . 26
Annex C (normative) Dimensions of the Petersen column . 27
Annex D (informative) Additional information on Round Robin analysis . 28
Annex E (informative) Additional information on parallel tests . 34
Bibliography. 41
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Foreword
This Technical Specification (CEN/TS 15439:2006) has been prepared by Working Group CEN/BT/TF 143
“Measurement of organic contaminants (tar) in biomass producer gases”, the secretariat of which is held by NEN.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.
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Introduction
The main contaminants in the product gases of biomass gasification are dust and soot particles, tars, alkali
metals, acid gases and alkaline gases. Measuring techniques for these contaminants allow determination of the
functioning of the gasifier itself, of the efficiency of the gas cleaning process and of the quality of the cleaned gas
to be used in, for instance, a gas engine or gas turbine.
The development of this Technical Specification started out of the need for a reliable method for the
measurement of tars. For most contaminants in product gases of biomass gasification, well-developed
measurement techniques exist that are similar to techniques used for related technologies, such as coal
combustion and coal gasification. For tars, however, no well-developed and widely used measurement
techniques existed in these related technology fields. As some of the tars were (and are) seen as the major
problem causing contaminants in biomass gasification, manufacturers and other workers in this field used a
number of different sampling and analysis methods to determine the level of tars. As a result, comparison of data
and definition of clear maximum allowable concentrations for tars was problematic. This formed an obstacle for
market introduction of biomass gasification systems, as tars can cause damage or require an unacceptable level
of maintenance.
This Technical Specification gives methods for sampling and analysis of tars and particles in product gases from
biomass gasifiers operating under atmospheric or pressurised conditions. The sampling and analysis methods in
this Technical Specification differ from most of the methods used for sampling organic compounds present in the
gaseous emissions from various industrial processes such as flue gases or automobile exhaust gases. The
differences are related to the fact that the levels of the organic compounds present in the gasification product
gases exceed the levels found in flue gases generally by more than three orders of magnitude. Hence the
methods described in this Technical Specification are not intended to be applicable for sampling organic
compounds in trace concentrations (sub-ppm range).
The tar-containing biomass gasification product gas is formed by thermal decomposition of biomass at sub
stoichiometric conditions (pyrolysis, gasification) and is typically used to produce electricity, heat, or gaseous or
liquid biofuels. As tars from pyrolysis or gasification of coal are similar in nature compared to (high temperature)
biomass gasification tars, coal tars can also be sampled and analysed with this Technical Specification.
Biomass in this Technical Specification is defined as material of biological origin excluding material embedded in
)
1
geological formations and transformed to fossil . The Technical Specification is developed for uncontaminated
biomass, a term being defined in Clause 3 "Terms and definitions". Tests on accuracy and repeatability of the
Technical Specification have been performed with uncontaminated biomass. The Technical Specification may
also be used for tars produced from gasification of contaminated biomass and for tars produced from gasification
of fossil fuels, however, in this case it is up to the user to assess to what extent the concentration and
composition of the tars differ from gasification of uncontaminated biomass. Biomass gasifiers, as referred to in
this Technical Specification, can be updraft fixed bed gasifiers, downdraft fixed bed gasifiers, stage divided
gasifiers, fluidised bed gasifiers, entrained flow gasifiers and other types of gasifiers. Updraft and downdraft fixed
bed, fluidised bed and entrained flow gasifiers are described in more detail in a background Technical Report [1].
1)
This definition is the same as the definition of biomass in CEN TC 335 Solid Biofuels
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1 Scope
This Technical Specification gives methods for sampling and analysis of tars and particles in order to determine
the load of these contaminants in flowing biomass gasification product gases. The Technical Specification is
3
applicable to sampling and analysis of tars and particles in the concentration range typically from 1 mg/m to 300
n
3 3 3
g/m (tars) and from 20 mg/m to 30 g/m (particles) at all relevant sampling point conditions
n n n
), ) 3
2 3
(0 °C to 900°C and 60 kPa to 6000 kPa (0,6 bar to 60 bar) ) . Particle concentrations lower than 20 mg/m
n
are outside the scope of this Technical Specification and can be measured according to EN 13284-1.
Application of this Technical Specification allows determination of five different parameters:
3
A. The concentration of gravimetric tar in mg/m ;
n
3
B. The concentration of individual organic compounds in mg/m . This Technical Specification gives data on
n
repeatability and reproducibility for the compounds listed in Annex B. The Technical Specification is also
applicable for other organic compounds (e.g. those mentioned in Annex A), but repeatability and
reproducibility have not been assessed for compounds other than those in Annex B;
C. The sum of concentrations of identified GC-detectable compounds listed in Annex B;
D. The sum of concentrations of all GC-detectable compounds with retention times in the range of benzene to
coronene calculated as naphthalene (benzene excluded), given that this sum of concentrations can be
determined.
3
E. The concentration of particles in mg/m .
n
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
ISO 9096 Stationary source emissions – Manual determination of mass
concentration of particulate matter
3 Terms and definitions
For the purposes of this Technical Specification, the following terms and definitions apply.
3.1
aerosol
suspension of solid or liquid particles in a gas
NOTE The term aerosol includes both the particles and the suspending gas. The particle size may range from about
0,002 µm to more than 100 µm.
3.2
biomass
material of biological origin, excluding material embedded in geological formations and transformed to fossil
NOTE This definition is the same as the definition of biomass in CEN TC 335 Solid Biofuels [7].
)
2
In fact it is not correct to give a concentration or to give concentration ranges for “tar” (see also its definition in Clause 3). This Technical
Specification is designed and has been evaluated for measurement of tar and particles in the following concentration ranges:
3 3
Gravimetric tar 500 mg/m to 300 g/m
n n
3 3
Sum of GC-detectable tars 1 mg/m to 300 g/m
n n
3 3
Particles 20 mg/m to 30 g/m
n n
The concentration range mentioned for gravimetric tar is a range based on a sampling time of 2 h. Lower concentration limits can be
3
attained with proportionally longer sampling times (e.g. 100 mg/m with a sampling time of 10 h). Due to the determination method, it is
n
recommended not to determine gravimetric tar below the concentration limit.
)
3
The performance characteristics in Clause 14 are determined under atmospheric conditions. Under pressurised conditions, the Technical
Specification as a whole has not been evaluated. However, sampling under pressurised conditions is based on relevant experience
(relevant construction details of probes are mentioned in a background document [1]) and the analysis of the liquid samples is identical for
atmospheric and pressurised gasification. Therefore, pressurised conditions are included in this Technical Specification.
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3.3
contaminated biomass
biomass not being uncontaminated biomass
NOTE See 3.20.
3.4
downdraft gasification
gasification process in which a bed of solid carbon-based material moves slowly downward under gravity as it is
)
4
gasified, whilst the gasification agent (e.g. air) passes through the bed co-currently . The product gas leaves the
gasifier at the base
3.5
entrained flow gasification
gasification process in which carbon-based material is fed co-currently with the gasification agent (e.g. air,
oxygen or steam) and where the velocity of the gasification agent is sufficiently high to maintain entrainment of
the carbon-based material
3.6
fluidised bed gasification
gasification process in which carbon-based material is fed into a suspended (bubbling) or circulating hot bed of
inert particles (e.g. sand or ash), the suspension or circulation being created by the gasification agent (e.g. air,
oxygen or steam)
3.7
gasification
thermal conversion of carbon-based materials into a product gas composed primarily of CO, H , methane and
2
lighter hydrocarbons in association with CO , H O and N depending on the specific gasification process
2 2 2
considered
NOTE Gasification can be accomplished by direct internal heating provided by partial oxidation using e.g.
substoichiometric air or oxygen. Alternatively, concepts based on either indirect heating methods or autothermal methods
using exothermic reduction reactions may be applied.
3.8
GC detection limit
lowest concentration that can be detected by the GC equipment.
NOTE This concentration depends on the quality of the equipment and is defined as twice the noise level in the GC
chromatogram.
3.9
GC-detectable tar
tar that can be measured as a gaseous mixture of individual components according to standard (or state of the
art) gas chromatographic practice
3.10
gravimetric tar
evaporation/distillation residue from particle free sampling solution(s) determined by gravimetric analysis
3.11
isokinetic sampling
sampling at a flow rate such that the velocity and direction of the gas entering the sample nozzle are the same as
they are in the gas in the duct at the sampling point
3.12
normal conditions
conditions with a temperature of 273,15 K, pressure of 101 325 Pa (1,013 25 bar) and on a dry basis
)
4
Co-current does not automatically mean downdraft but can also mean updraft, although co-current updraft designs are uncommon.
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3.13
particles
solid residue collected by a particle filter after solvent extraction or solid residue from filtration of sampling
solution(s)
NOTE Solid residue may contain a small amount of insoluble polymerised tar.
3.14
Petersen column
alternative to impinger bottles in the sampling train. The Petersen column is a piece of glass equipment with two
containers for liquid, which act as washing stages to remove soluble compounds from a gas. The two containers
are separated by a glass frit. A description of the Petersen column is given in Annex C
3.15
product gas
gas resulting from gasification
NOTE The product gas from biomass gasification can be used as a fuel (then also named fuel gas, producer gas or
water gas) in internal and external combustion engines, fuel cells, and other prime movers for heat and mechanical or
electrical power. Alternatively, the product gas may be used as a feedstock (then also named synthesis gas or syngas) for the
petrochemical and refining industries, e.g. for the production of liquid fuels or chemicals.
3.16
pyrolysis
thermal decomposition in the absence of an oxygen source such as air, oxygen, H O or CO
2 2
3.17
sampling train
equipment used for sampling particles and tars, consisting of the particle filter, the impinger bottles or Petersen
column, the pump and flow measuring equipment and all connecting tubes
3.18
soxhlet extraction
batch extraction method at the boiling point of the used solvent and atmospheric pressure
3.19
tar
generic (unspecific) term for entity of all organic compounds present in the gasification product gas excluding
gaseous hydrocarbons (C1 through C6)
3.20
uncontaminated biomass
biomass from the following sources:
• Products from agriculture and forestry;
• Vegetable waste from agriculture and forestry;
• Vegetable waste from the food processing industry;
• Wood waste, with the exception of wood waste that may contain halogenated organic compounds or heavy
metals as a result of treatment with wood preservatives or coatings, and including in particular wood derived
from construction and demolition waste
NOTE This definition reflects the biomass categorised as “solid biofuels“ under the scope of CEN TC 335 Solid Biofuels [7].
3.21
updraft gasification
gasification process in which a bed of solid carbon-based material moves slowly downward under gravity as it is
)
5
gasified, whilst the gasification agent (e.g. air or oxygen) passes through the bed counter-currently , where the
product gas leaves the gasifier at the top
)
5
Counter-current does not automatically mean updraft but can also mean downdraft, although counter-current downdraft designs hardly
exist.
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4 Symbols and abbreviations
BTX : Benzene, Toluene and Xylenes
GC-FID : Gas Chromatography – Flame Ionisation Detector
GC-MS : Gas Chromatography – Mass Spectrometer
id : Internal diameter
ISTD : Internal Standard
3
m : Cubic metre at normal conditions
n
M/z : Molar mass-to-charge ratio
MW : Mega Watt based on the thermal input of the biomass (lower heating value)
th
Pa : Pascal
PAH : Polycyclic Aromatic Hydrocarbons
PTFE : Polytetrafluoroethene
NOTE The designation of the variables RF, M and A is explained just below the equations in which they are used.
5 Principle of the measurement method
5.1 Introduction
The principle of the measurement method is based on the discontinuous extractive sampling of a representative
part of a gas stream containing particles and organic compounds (tar) under isokinetic conditions. The
determination of particles and tars in biomass gasification product gases is carried out in two steps: sampling and
analysis.
5.2 Sampling
Samples of tars and particles are taken at a gasifier sample port, which is gas tight so that neither can gas
escape from the system nor can oxygen enter it. The sampling train is configured as a heated probe with a
heated particle filter to remove solid matter. The volatile tars are trapped in heated or chilled impinger bottles
containing an organic liquid absorbent. The sampled gas volume is measured under dry conditions by means of a
gas meter. The samples are prepared on-site and are stored until they can be analysed.
5.3 Analysis
5.3.1 Introduction
The samples are analysed in a laboratory. The particle filter containing the particle sample is Soxhlet extracted in
order to remove adsorbed tars. Subsequently the amount of particles is determined gravimetrically. The tars from
the Soxhlet extraction are added to the liquid tar samples. If required, the liquid tar samples are filtered for
removal of solid matter.
For the analysis of tars two methods are given in this Technical Specification, analysing respectively gravimetric
tar and gas chromatographable tar. The user is free to choose either one or both methods, depending on the kind
of information needed. The users attention is drawn to the fact that the two resulting values are not
supplementary, but that there is an overlap between the two tar values. The user’s attention is also drawn to the
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fact that the gravimetric method is not suitable for clean gases with low tar concentrations and that its
reproducibility is significantly poorer than the GC analysis method.
5.3.2 Gravimetric determination
Part of the homogeneous liquid sample is evaporated under well-defined conditions and the evaporation residue
3
is weighed. The result is then recalculated to give the amount of gravimetric tar in mg per m of product gas.
n
5.3.3 Gas chromatography
Part of the liquid sample is injected into a gas chromatograph (GC). This analysis results in concentrations of
3
individual tar compounds and of the sum of GC-detectable tars, both in mg per m of product gas.
n
Positive identification of the condensed material as biomass tar is performed using GC-MS. The presence of tar
is indicated typically by the presence of the US-EPA suite of PAH compounds, phenols and BTX. Quantitative
determination of each compound is performed either by GC-MS or GC-FID analysis using internal standards.
Please note that not all of the tar constituents are amenable to GC analysis because of the presence of high
molecular weight material, thermal labile or extreme polar compounds. GC analysis will usually determine more
than 80% of the tar, the remainder being e.g. high-molecular weight material of >350 g/mol. However, for updraft
gasifier tars the fraction determined may be considerably lower.
6 Reagents
6.1 Solvent for tar collection and Soxhlet extraction
Isopropanol (2-propanol) shall be used as the solvent for tar collection, for Soxhlet extraction and for sample
preparation and analysis. The minimum purity of the isopropanol is 99%. It shall be verified with a blank GC
determination that the solvent does not contain GC detectable amounts of relevant tar compounds.
Ethanol shall be used in gravimetric analysis procedure to remove trace water from evaporation residue
(gravimetric tar). The required minimum purity is 99%.
Other solvents like ethanol or dichloromethane shall only be used for rinsing of the glass and PTFE equipment
when cleaning with isopropanol leaves tar residues that can be visually observed.
6.2 Carrier gas in gas chromatography
The carrier gas shall be helium of acceptable purity or a suitable alternative as specified by the GC manufacturer.
6.3 Calibration standards
All reagents shall be of recognised analytical reagent quality, preferably analytical or "pro analysis" grade. The tar
compounds are named in Annex A and Annex B.
7 Equipment
7.1 Equipment for sampling
7.1.1 Description of the sampling equipment
The equipment for sampling consists of a heated probe, a heated particle filter, a condenser, a series of impinger
bottles containing a solvent for tar absorption, and equipment for pressure and flow rate adjustment and
measurement. Upstream of the condenser the tubes connecting these parts are heated in order to prevent tar
condensation. Temperatures for heating the probe, filter and tubes are specified to avoid both condensation of
tars and thermal decomposition of tars. Temperatures for the condenser and the impingers are specified to
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