Characterising aerosols in flue gas using FTIR, ELPI + and impinger methods

Transcription

1 Characterising aerosols in flue gas using FTIR, ELPI + and impinger methods Jan Mertens and Nathalie Faniel jan.mertens@laborelec.com LABORELEC

2 Background Reduction of CO 2 emissions from fossil fuel combustion in coal fired power plants Post combustion CO 2 capture is one of the possible options Objective of the research To characterise and minimize unwanted emissions into the air from postcombustion CO 2 capture pilot plants Three measuring methods: (1) FTIR, (2) ELPI+, (3) impinger method 2

3 What is Post Combustion Carbon Capture (PCCC)? To pipeline 3 LABORELEC

4 What is Post Combustion Carbon Capture (PCCC)? To pipeline 4 LABORELEC

5 Why emission monitoring in PCCC & challenges? Challenges? Top of absorber: Water saturated & low temperatures To pipeline Top of desorber: 99 vol% CO 2 stream Water interferes in IR Water saturation: risk of loosing water soluble organic & inorganic components 5 LABORELEC

6 Materials and methods used On-line measurement of organics and inorganics at ppm level Calibrated for MEA, On-line measurement of PM size distribution & concentration between 6 nm 10 µm FTIR ELPI + Off-line measurement of the gas phase: mostly used for NH 3, MEA, aldehydes, nitrosamines Manual sampling 6

7 Materials and methods used On-line measurement of organics and inorganics at ppm level Calibrated for MEA, FTIR 7

8 Fluegases at the oulet of the pilot? Top of absorber: Should be amine free To pipeline 8 LABORELEC

9 High amine emissions have been observed at different amine based carbon capture pilot plant campaigns at different locations High MEA emissions measured using FTIR at different pilots in EU: Mertens, J., M. L. Thielens, J. Knudsen and J. Andersen, On-line monitoring and controlling emissions in amine post combustion carbon capture: a field test. International Journal of Greenhouse Gas Control, 6, 2-11 Mertens, J., H. Lepaumier, D. Desagher and M.L. Thielens, Understanding Ethanolamine (MEA) and ammonia emissions from amine based post combustion carbon capture: lessons learned from field tests. International Journal of Greenhouse Gas Control, 13, High emissions measured also in US: Project NCCC in Alabama From 0.25 to 1.6 g/nm³ 9

10 Fluegases at the oulet of the pilot? Top of absorber: Should be amine free To pipeline Wash water section: Efficiency? 10 LABORELEC

11 Water wash not successful in removing all MEA emissions indicates the presence of MEA in the form of aerosols Water wash only reduces amine (MEA) emissions to around 50 %: not all amine is gaseous amine aerosols DUE TO INCOMING SO 3 AEROSOLS PRESENT IN THE FLUE GAS OF COAL FIRED POWER PLANTS need to characterise incoming aerosols 11

12 Materials and methods used On-line measurement of PM size distribution & concentration between 6 nm 10 µm ELPI + 12

13 SO 3 aerosols are VERY small (< 100 nm) but grow when concentrations rise 1mg m -3 H 2 S0 4 13

14 SO 3 aerosols are VERY small (< 100 nm) but grow when concentrations rise 1mg m -3 H 2 S mg m -3 H 2 S0 4 14

15 SO 3 aerosols are VERY small (< 100 nm) but grow when concentrations rise 1mg m -3 H 2 S mg m -3 H 2 S0 4 Dilution has no effect on PSD at small H 2 SO 4 concentrations aerosols are close to dry droplet diameter At large concentrations, aerosols shrink with increasing dilution more end up in the filter stage (< 10 nm) filter stage is known to be vulnerable to overestimation! Mertens, J., L.. Brachert, D. Desagher, M.L. Thielens,, P. Khakharia, E. Goetheer and K. Schaber, ELPI+ measurements of aerosol growth in an amine absorption column. International Journal of Greenhouse 15 Gas Control, in press

16 Compare numbers of aerosols between CPC and ELPI + UF-CPC = Universal Fluid Condensation Particle Counter range of 4 nm up to 10 μm ELPI + = Electrostatic Low Pressure Impactor range of 6 nm up to 10 μm 16 D50% Stage [µm]

17 Compare numbers of aerosols between CPC and ELPI + 17

18 Compare numbers of aerosols between CPC and ELPI + Good agreement between ELPI+ and CPC: ~10 8 1/cm³ number concentration only marginally increases with increasing SO 3 concentration! Slight overestimation of ELPI+ when too large percentage is in the filter stage (< 10nm) so numbers seem to increase 18 with increasing dilution!

19 Fluegases at the oulet of the pilot? Top of absorber: Should be amine free To pipeline Wash water section: Efficiency Aerosol removal In order to assess the impact on the amine measurement 19 LABORELEC

20 Materials and methods used On-line measurement of organics and inorganics at ppm level Calibrated for MEA, FTIR Off-line measurement of the gas phase: mostly used for NH 3, MEA, aldehydes, nitrosamines Manual sampling 20

21 SAMPLING SAMPLE STORAGE ANALYSIS No standardized methodology for manual sampling and consequent analysis of the gas phase in PCCC 3 aspects to be considered for an accurate and precise measurement: Iso-kinetics Flow rate Set-up Ad-/Absorbent Sampling time Temperature Time Type of sampling container Method Limit of Detection Limit Of Quantification Sensitivity Accuracy 21

22 SAMPLING SAMPLE STORAGE ANALYSIS No standardized methodology for manual sampling and consequent analysis of the gas phase in PCCC 3 aspects to be considered for an accurate and precise measurement: Iso-kinetics Flow rate Set-up Ad-/Absorbent Sampling time Temperature Time Type of sampling container Method Limit of Detection Limit Of Quantification Sensitivity Accuracy Two sampling rates Bubbler/ Impinger 22 Three laboratories

23 Effect of the sampling flow rate 180 C FTIR 180 C FID 80 C Small pump Oven Silica gel (3 l/min) Gas counter bubbler LOW FLOW Ice Bath Absorbing solution bubblers Washing Section Main gas flow 80 C Oven HIGH FLOW Ice Bath impingers Silica gel Absorbing solution Pump (10 l/min) Gas counter impinger 23

24 Effect of sampling flow rate High Flow FTIR Low Flow 24

25 MEA emissions (% maximum value) Effect of sampling on MEA emissions In absence of aerosols, MEA measured concentration are higher than compared to FTIR but same order of magnitude between laboratories less MEA aerosols In presence of aerosols, MEA measured concentration are much lower than compared to FTIR but increases when increasing the sampling flow rate MEA aerosols Improved capture efficiency when using impingers instead of bubblers and the higher flow Without MEA aerosols With MEA aerosols FTIR A C D Test 1-25 Low Flow 0 Test 2 - Low Flow Test 3 - High Flow

26 MEA emissions (% maximum value) Effect of sampling on MEA emissions In absence of aerosols, MEA measured concentration are higher than compared to FTIR but same order of magnitude between laboratories less MEA aerosols In presence of aerosols, MEA measured concentration are much lower than compared to FTIR but increases when increasing the sampling flow rate MEA aerosols Improved capture efficiency when using impingers instead of bubblers and the higher flow Possible explanations: In the manual sampling set-up, a part of the aerosols travels without being captured contrary to FTIR where all aerosols are evaporated at 180 C Without MEA aerosols With MEA aerosols FTIR A C D Overestimation by FTIR in the high MEA value range? (only calibrated up to 55 mg.nm -3 ) Test 1-26 Low Flow Test 2 - Low Flow Test 3 - High Flow

27 Summary Objective of the research To characterise and minimize unwanted emissions into the air from postcombustion CO 2 capture pilot plants Three measuring methods: (1) FTIR, (2) ELPI+, (3) impinger method Steps (1) FTIR: High unwanted amine emission from time to time High amine emissions are related to the presence of aerosols (2) ELPI + Characterisation of the aerosols FTIR and (3) impinger method Confirmation of the importance of the aerosols when high amine concentrations occur Confirmation that the amine is partially present as aerosol 27

28 Conclusions & future research ELPI + suitable for aerosol counting and size information H 2 SO 3 aerosols: high number concentrations (> 10 8 cm -3 ) very small sizes (<100 nm) H 2 SO 3 concentration numbers remain constant but sizes However, take care interpreting sizes when diluting! Aerosols aerosols potentially travel across the manual samplings set-up without being captured In presence of aerosols, high discrepancy between FTIR and manual measurements are noticed Standardisation work is urgently needed for the emission monitoring in CCS, in particular when aerosols are present! 28

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