The potential of ETV-ICP OES for characterization of energy resources Direct solid sample analysis of elements

Transcription

1 The potential of ETV-ICP OES for characterization of energy resources Direct solid sample analysis of elements Daniela Bauer, Thomas Vogt, Matthias Otto Radebeul, Deutsches EnergieRohstoff-Zentrum Institute for Analytical Chemistry Leipziger Str / Dipl. Nat. Daniela Bauer IGCC & XtL Technologies

2 Analytical instruments ETV electrothermal vaporization ETV 4c with autosampler AWD 5 (Spectral Systems) ICP OES atomic emission spectroscopy with inductive coupled plasma ICP OES in radial mode (ARCOS SOP) ICP OES in axial mode (ARCOS EOP) (SPECTRO Analytical Instruments GmbH ) (Fig.: SPECTRO Analytical Instruments GmbH) 2 2

3 ETV - principle (Fig.: Thomas Vogt, TU Bergakademie Freiberg) ETV electrothermal vaporization Approximately 3 mg of sample weighed in graphite boat Resistive heating in graphite tube Heating program up to 3 C (24 C); max. heating rate 8 K/s Temperature-dependent vaporization of analytes Transportation of aerosol into plasma of atomic emission spectrometer 3 3

4 ICP OES - principle (Fig.: SPECTRO Analytical Instruments GmbH - modified) ICP OES atomic emission spectroscopy with inductive coupled plasma Excitation of electrons to a higher energy level Relaxion of electrons to a lower state Emission of energy difference in form of radiation Detection of element-specific radiation 4 4 axial plasma (EOP) 4

5 Argonne Premium Sample Bank Argonne Premium Coals Collection of 8 North American reference coal samples Result of cluster analysis of whole coal seam data from the Pennsylvania State Coal Sample Data Base Used worldwide in numerous coal studies results could be verified 5 5

6 Argonne Premium Coals (APC) Sample ID Seam Rank Upper Freeport Wyodak Anderson Medium volatile bituminous Subbituminous Illinois High volatile bituminous Pittsburgh High volatile bituminous Pocahontas Low volatile bituminous Blind Canyon High volatile bituminous (Fig.: David Nennstiel, TU Bergakademie Freiberg) Lewison Stockton High volatile bituminous Covering the rank range from lignite to semi-anthracite Beulah-Zap Lignite High variety of maceral contents Prepared and stored under controlled conditions 6 6

7 Coal ash fusion temperature in K Elements of interest for industry B = Fe 2O 3 +CaO+MgO+K 2 O+Na 2 O+(P 2 O 5 ) A SiO 2 +Al 2 O 3 +TiO 2 R S = B A dry S % F U = B A (K 2O + Na 2 O) S R = SiO 2 SiO 2 +Fe 2 O 3 +CaO+MgO 1 Base to Acid ratio Slagging index Fouling index Slag viscosity index B/A R S F U S R acid base Base to acid ratio Ni, Pb, V in coke, pet coke and refuse (Fig.: David Nennstiel, TU Bergakademie Freiberg) Coal/ash chemistry correlates with furnace slagging, fouling and corrosion problems Coal/ash chemistry provides good bases by application of several empirical indicators 7 7

8 Overview of the quali-/quantitative determinable elements Determination of major, minor and trace elements possible Determination of element contents in solids (coal, ash, cokes, biomass) and also in liquid samples (pyrolysis oil) 8 8

9 Growing need for a rapid-solid sampling analysis Traditional methods require time-consuming sample pretreatment Risk of incomplete sample dissolution and sample contamination Risk of losing by volatilization of elements during preconcentration process ashing Elements like Si, Cl only in solid samples measurable (HCl/HF as digesition chemicals; SiF4 ) Need of large amounts of high-purity or hazardous chemicals (like HF) 9 9

10 Multielement-analysis by ETV-ICP OES 9.6x x x1 6 K Na Fe S Si di/dt 6.x x x1 6 Ca Temp Temperature [ C] 2.4x x Transient signals of selected elements Sample: APC, high-volatile bituminous coal, from the Illinois #6 seam 1 1

11 Decreasing element content depending on temperature 1 24 Sulfur content [%] Sulfur release Sulfur content Temperature Temperature [ C] Determination of content change as a function of increasing temperature, exemplified by S 11 11

12 Multielement-analysis by ETV-ICP OES 1 24 Sulfur content [%] Sulfur release Sulfur content Temperature Temperature [ C] Integrated area total element content No possibility for comparison between different element contents calibration necessary 12 12

13 Intensity [cps] Calibration of sulfur with different reference materials 3,5E+7 3,E+7 2,5E+7 R² = ,E+7 1,5E+7 1,E+7 5,E+6,E+ NIST 1632d coal NIST 1635a coal NIST 1635a ash NIST 1632d Day 2 NIST 1635a Day 2 Linear (Regression),1,2,3,4,5,6,7,8,9 Quantity [mg] Calibration with different reference materials is possible (also with ashes) NIST SRM 1632d (bituminous coal), NIST SRM 1635a (subbituminous coal) NCS FC28123 (anthracite), NCS FC28127 (bituminous coal) for other elements (no data for sulfur) Daily calibration is not necessary 13 13

14 Comparison of results with published values published value ETV-ICP OES axial plasma (EOP) ETV-ICP OES radial plasma (SOP) S - content [ppm] Comparison of total contents between samples, presented by the example of S Good agreement of results with published values 14 14

15 Determination of total major element contents by ETV-ICP OES Al - content [ppm] Ca - content [ppm] Fe - content [ppm] K - content [ppm] Mg - content [ppm] Na - content [ppm] published value ETV-ICP OES axial plasma (EOP) ETV-ICP OES radial plasma (SOP) Lit.: Compilation of Multitechnique Determinations of 51 Elements in 8 (APC); Curtis A. Palmer and Sarah A. Klizas Si - content [ppm] Ti - content [ppm] 15 15

16 Determination of total minor element contents by ETV-ICP OES Ba - content [ppm] Cr - content [ppm] Cu - content [ppm] Mn - content [ppm] Ni - content [ppm] P - content [ppm] published value ETV-ICP OES axial plasma (EOP) ETV-ICP OES radial plasma (SOP) Lit.: Compilation of Multitechnique Determinations of 51 Elements in 8 (APC); Curtis A. Palmer and Sarah A. Klizas Pb - content [ppm] V - content [ppm] 16 16

17 di/dt - S Determination of element release sulfur speciation by ETV-ICP OES 1.5x x1 7 - S 1.5x1 7 - S 1.5x x x1 7 - S 9.x1 6 9.x1 6 9.x1 6 6.x1 6 6.x1 6 6.x1 6 3.x1 6 3.x1 6 3.x x x x x1 7 - S - S - S 1.2x x1 7 9.x1 6 9.x1 6 9.x1 6 6.x1 6 6.x1 6 6.x1 6 3.x1 6 3.x1 6 3.x x x x x1 7 - S - S SRM 1632d - S SRM 1632d 1.2x x d 1632d 9.x1 6 9.x1 6 9.x1 6 6.x1 6 6.x1 6 6.x1 6 3.x1 6 3.x1 6 3.x di/dt - S di/dt - Fe Fast comparison of total element contents between samples, presented by the example of S Comparison of element release, presented by the example of S and Fe - different release profiles between samples 17 17

18 Determination of element release sulfur speciation by ETV-ICP OES 1.2x1 6 SRM 1632d SRM 1632d + FeS SRM 1632d SRM 1632d + FeS x di/dt 8.x1 5 6.x1 5 4.x Temperature [ C] 2.x x x x1 6 2.x x x1 6 8.x1 5 4.x1 5 Pyrite decomposition - multistep process (highlighted with gray area): 4 2 di/dt Fe - SRM 1632d S - SRM 1632d Fe - SRM 1632d + FeS S - SRM 1632d + FeS Temperature [ C] pyrite (FeS 2 ) pyrrhotite (Fe(1-x)S; (x =.2)) troilite (FeS) iron/sulfur 18 18

19 Determination of sulfur species by ETV-ICP OES and DIN di/dt 3.6x1 6 organic sulfur pyritic sulfur 3.x1 6 cumulative signal residual signal 2.4x x x1 6 6.x1 5 Independent variable 3x1 5 2x1 5 1x1 5-1x1 5-2x1 5 Residual of di/dt Result of peak assignment experiments Peak deconvolution sulfur distribution Possibility of sulfur speciation (organic and pyritic sulfur) depending on element release Without handling of chemicals Low time effort (few seconds per sample) -3x DIN ISO Multistage sequential extraction process Use of chemicals Very time consuming (several hours per sample) 19 19

20 N D W V U T P O C P ITT W Y S RM Determination of sulfur species by ETV-ICP OES and DIN E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure E T V - ICP O E S L it e r a t ure organic sulfur sulfatic sulfur pyritic sulfur Good match between speciation-results obtained by measuring with ETV-ICP OES and DIN No determination of S sulfatic in such small contents in contrast to S pyritic and S org. by ETV-ICP OES

21 Conclusion Multielement analysis method with high dynamic range Determination of major, minor and trace elements (no preconcentration by ashing necessary) Most elements simultaneous quali- / quantitative measurably Solid and liquid samples analyzable Fast direct analysis method No sample preparation necessary (no risk of contamination / loss of analytes) Duration of analysis only seconds per sample Elements like Si, Cl only in solid samples measurable (HCl/HF as digesition chemicals; SiF 4 ) No sample modification element speciation Analysis by RFA ashing necessary, analysis by ICP OES without ETV digestion necessary Not always calibration necessary (percentage distribution, stable system) Little use of sample material (1-1 mg) Limited amount of sample material (high complexity of reactor experiments for ashing under reducing conditions low yields) 21 21

22 ETV-ICP OES - an analytical method for characterization of energy resources economical automatable elemental speciation quali-/quantitative simultaneous multielement analysis without sample preparation ecological fast 22 22

23 ETV-ICP OES - an analytical methode for characterization of energy resources Thank you for your attention Thanks to: German Centre for Energy Resources (DER) Institute for Analytical Chemistry, Atomic Spectroscopy This publication has been funded by the German Centre for Energy Resources, support code: 3IS221A 23 23

24 Influence of heating programme on element release di/dt 1.6x x x1 7 1.x1 7 8.x1 6 6.x1 6 4.x1 6 2.x1 6 a) Heating rate: 8 Ks Temperature [ C] di/dt 1x1 7 9x1 6 8x1 6 7x1 6 6x1 6 5x1 6 4x1 6 3x1 6 2x1 6 1x1 6 b) Heating rate: 3 Ks Temperature [ C] di/dt 5.x1 6 c) 4.5x1 6 4.x x1 6 3.x x1 6 2.x x1 6 1.x1 6 5.x1 5 Heating rate: 16 Ks Temperature [ C] di/dt 5.x x1 6 4.x x1 6 3.x x1 6 2.x x1 6 1.x1 6 5.x1 5 d) Heating rate: 14 Ks -1 / 48 Ks Temperature [ C] Strong influence of heating programme on the element release, exemplified by S Optimal heating programme depends on the issue of analysis (e.g. total contents, speciation)