Abstract
The performance of a thermal denuder (thermodenuder—TD) and a fresh catalytic stripper (CS) was assessed by sampling laboratory aerosol, produced by different combinations of sulfuric acid, octacosane, and soot particles, and marine exhaust aerosol produced by a medium-speed marine engine using high sulfur fuels. The intention was to study the efficiency in separating non-volatile particles. No particles could be detected downstream of either device when challenged with neat octacosane particles at high concentration. Both laboratory and marine exhaust aerosol measurements showed that sub-23 nm semi-volatile particles are formed downstream of the thermodenuder when upstream sulfuric acid approached 100 ppbv. Charge measurements revealed that these are formed by re-nucleation rather than incomplete evaporation of upstream aerosol. Sufficient dilution to control upstream sulfates concentration and moderate TD operation temperature (250°C) are both required to eliminate their formation. Use of the CS following an evaporation tube seemed to eliminate the risk for particle re-nucleation, even at a ten-fold higher concentration of semi-volatiles than in case of the TD. Particles detected downstream of the CS due to incomplete evaporation of sulfuric acid and octacosane aerosol, did not exceed 0.01% of upstream concentration. Despite the superior performance of CS in separating non-volatile particles, the TD may still be useful in cases where increased sensitivity over the traditional evaporation tube method is needed and where high sulfur exhaust concentration may fast deplete the catalytic stripper adsorption capacity.
| Original language | English |
|---|---|
| Pages (from-to) | 420-432 |
| Number of pages | 13 |
| Journal | Aerosol Science and Technology |
| Volume | 52 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 16 Jan 2018 |
| MoE publication type | A1 Journal article-refereed |
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Comparative performance of a thermal denuder and a catalytic stripper in sampling laboratory and marine exhaust aerosols. / Amanatidis, Stavros; Ntziachristos, Leonidas; Karjalainen, Panu; Saukko, Erkka; Simonen, Pauli; Kuittinen, Niina; Aakko-Saksa, Päivi; Timonen, Hilkka; Rönkkö, Topi; Keskinen, Jorma.
In: Aerosol Science and Technology, Vol. 52, No. 4, 16.01.2018, p. 420-432.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - Comparative performance of a thermal denuder and a catalytic stripper in sampling laboratory and marine exhaust aerosols
AU - Amanatidis, Stavros
AU - Ntziachristos, Leonidas
AU - Karjalainen, Panu
AU - Saukko, Erkka
AU - Simonen, Pauli
AU - Kuittinen, Niina
AU - Aakko-Saksa, Päivi
AU - Timonen, Hilkka
AU - Rönkkö, Topi
AU - Keskinen, Jorma
PY - 2018/1/16
Y1 - 2018/1/16
N2 - The performance of a thermal denuder (thermodenuder—TD) and a fresh catalytic stripper (CS) was assessed by sampling laboratory aerosol, produced by different combinations of sulfuric acid, octacosane, and soot particles, and marine exhaust aerosol produced by a medium-speed marine engine using high sulfur fuels. The intention was to study the efficiency in separating non-volatile particles. No particles could be detected downstream of either device when challenged with neat octacosane particles at high concentration. Both laboratory and marine exhaust aerosol measurements showed that sub-23 nm semi-volatile particles are formed downstream of the thermodenuder when upstream sulfuric acid approached 100 ppbv. Charge measurements revealed that these are formed by re-nucleation rather than incomplete evaporation of upstream aerosol. Sufficient dilution to control upstream sulfates concentration and moderate TD operation temperature (250°C) are both required to eliminate their formation. Use of the CS following an evaporation tube seemed to eliminate the risk for particle re-nucleation, even at a ten-fold higher concentration of semi-volatiles than in case of the TD. Particles detected downstream of the CS due to incomplete evaporation of sulfuric acid and octacosane aerosol, did not exceed 0.01% of upstream concentration. Despite the superior performance of CS in separating non-volatile particles, the TD may still be useful in cases where increased sensitivity over the traditional evaporation tube method is needed and where high sulfur exhaust concentration may fast deplete the catalytic stripper adsorption capacity.
AB - The performance of a thermal denuder (thermodenuder—TD) and a fresh catalytic stripper (CS) was assessed by sampling laboratory aerosol, produced by different combinations of sulfuric acid, octacosane, and soot particles, and marine exhaust aerosol produced by a medium-speed marine engine using high sulfur fuels. The intention was to study the efficiency in separating non-volatile particles. No particles could be detected downstream of either device when challenged with neat octacosane particles at high concentration. Both laboratory and marine exhaust aerosol measurements showed that sub-23 nm semi-volatile particles are formed downstream of the thermodenuder when upstream sulfuric acid approached 100 ppbv. Charge measurements revealed that these are formed by re-nucleation rather than incomplete evaporation of upstream aerosol. Sufficient dilution to control upstream sulfates concentration and moderate TD operation temperature (250°C) are both required to eliminate their formation. Use of the CS following an evaporation tube seemed to eliminate the risk for particle re-nucleation, even at a ten-fold higher concentration of semi-volatiles than in case of the TD. Particles detected downstream of the CS due to incomplete evaporation of sulfuric acid and octacosane aerosol, did not exceed 0.01% of upstream concentration. Despite the superior performance of CS in separating non-volatile particles, the TD may still be useful in cases where increased sensitivity over the traditional evaporation tube method is needed and where high sulfur exhaust concentration may fast deplete the catalytic stripper adsorption capacity.
UR - http://www.scopus.com/inward/record.url?scp=85041130555&partnerID=8YFLogxK
U2 - 10.1080/02786826.2017.1422236
DO - 10.1080/02786826.2017.1422236
M3 - Article
VL - 52
SP - 420
EP - 432
JO - Aerosol Science and Technology
JF - Aerosol Science and Technology
SN - 0278-6826
IS - 4
ER -