High temperature aerosol measurement

an alternative to dilution approach

Ville Niemelä, Erkki Lamminen, Kati Lehtoranta, Topi Rönkkö

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

In common engine exhausts particle measurements the sample temperature must be decreased to suitable level for measurement instrument, but when doing so there is a risk of water, sulfuric compound and VOC condensation and even nucleation. When the aim of the research is to study solid exhaust particles, this problem is typically handled with a dilution system that decreases the temperature and vapor pressures in two dilution stages including thermal treatment. However with low-emission vehicles this might also lower the particle concentration below instrument detection limit. Also, despite the controlled temperature profile dilution might still affect the size, composition and structure of particles, and uncertainty in dilution factor might decrease the measurement accuracy. To avoid these issues a new version of the Electrical Low Pressure Impactor ELPI+ was developed for high temperature, low concentration measurement. In this system the detector part, impactor, is heated to a high temperature up to 180C. This allows high temperature tailpipe aerosol measurement without dilution, without sample cooling and without VOC condensation. In other words, the particles are measured as they exist in the tailpipe. The system was tested with a 2-litre passenger car engine that was modified for natural gas fuel, known to produce very low particle emissions. In the test setup the exhaust gas composition was made adjustable by adding methane, propane, ethane and ethene to tailpipe-extracted side flow to mimic large bore engine (ship / power plant) emission composition. The developed High Temperature ELPI+ was used to measure the particle size distribution and concentration from tailpipe environment before catalysts. A two-mode particle size distribution was detected, one mode at below 10 nm particle size range and the other mode at around 30 nm. A volume-weighed distribution also shows a large particle mode at around 750 nm. In this presentation we describe the HT-ELPI+ and the engine and exhaust conditioning setup and present the particle measurement results from the system. We also discuss about the detected particles and their origin and present comparison results from other instruments that simultaneously measured diluted exhaust.
Original languageEnglish
Title of host publicationProceedings of the 25th Real-World Emissions Workshop
PublisherCRC Press
Publication statusPublished - 2015
MoE publication typeB3 Non-refereed article in conference proceedings
Event25th Annual Real-World Emissions Workshop
- Long Beach, United States
Duration: 22 Mar 201525 Mar 2015
Conference number: 25
https://crcao.org/workshops/RWE/25th_RWE_Workshop/EMarticleconfhighlights.pdf (25th Real-World Emissions Workshop)

Workshop

Workshop25th Annual Real-World Emissions Workshop
CountryUnited States
CityLong Beach
Period22/03/1525/03/15
Internet address

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dilution
aerosols
engines
impactors
volatile organic compounds
particle size distribution
condensation
particle emission
exhaust gases
passengers
gas composition
natural gas
power plants
conditioning
ships
propane
ethane
temperature profiles
vapor pressure
low concentrations

Cite this

Niemelä, V., Lamminen, E., Lehtoranta, K., & Rönkkö, T. (2015). High temperature aerosol measurement: an alternative to dilution approach. In Proceedings of the 25th Real-World Emissions Workshop CRC Press.
Niemelä, Ville ; Lamminen, Erkki ; Lehtoranta, Kati ; Rönkkö, Topi. / High temperature aerosol measurement : an alternative to dilution approach. Proceedings of the 25th Real-World Emissions Workshop. CRC Press, 2015.
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Niemelä, V, Lamminen, E, Lehtoranta, K & Rönkkö, T 2015, High temperature aerosol measurement: an alternative to dilution approach. in Proceedings of the 25th Real-World Emissions Workshop. CRC Press, 25th Annual Real-World Emissions Workshop
, Long Beach, United States, 22/03/15.

High temperature aerosol measurement : an alternative to dilution approach. / Niemelä, Ville; Lamminen, Erkki; Lehtoranta, Kati; Rönkkö, Topi.

Proceedings of the 25th Real-World Emissions Workshop. CRC Press, 2015.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - High temperature aerosol measurement

T2 - an alternative to dilution approach

AU - Niemelä, Ville

AU - Lamminen, Erkki

AU - Lehtoranta, Kati

AU - Rönkkö, Topi

PY - 2015

Y1 - 2015

N2 - In common engine exhausts particle measurements the sample temperature must be decreased to suitable level for measurement instrument, but when doing so there is a risk of water, sulfuric compound and VOC condensation and even nucleation. When the aim of the research is to study solid exhaust particles, this problem is typically handled with a dilution system that decreases the temperature and vapor pressures in two dilution stages including thermal treatment. However with low-emission vehicles this might also lower the particle concentration below instrument detection limit. Also, despite the controlled temperature profile dilution might still affect the size, composition and structure of particles, and uncertainty in dilution factor might decrease the measurement accuracy. To avoid these issues a new version of the Electrical Low Pressure Impactor ELPI+ was developed for high temperature, low concentration measurement. In this system the detector part, impactor, is heated to a high temperature up to 180C. This allows high temperature tailpipe aerosol measurement without dilution, without sample cooling and without VOC condensation. In other words, the particles are measured as they exist in the tailpipe. The system was tested with a 2-litre passenger car engine that was modified for natural gas fuel, known to produce very low particle emissions. In the test setup the exhaust gas composition was made adjustable by adding methane, propane, ethane and ethene to tailpipe-extracted side flow to mimic large bore engine (ship / power plant) emission composition. The developed High Temperature ELPI+ was used to measure the particle size distribution and concentration from tailpipe environment before catalysts. A two-mode particle size distribution was detected, one mode at below 10 nm particle size range and the other mode at around 30 nm. A volume-weighed distribution also shows a large particle mode at around 750 nm. In this presentation we describe the HT-ELPI+ and the engine and exhaust conditioning setup and present the particle measurement results from the system. We also discuss about the detected particles and their origin and present comparison results from other instruments that simultaneously measured diluted exhaust.

AB - In common engine exhausts particle measurements the sample temperature must be decreased to suitable level for measurement instrument, but when doing so there is a risk of water, sulfuric compound and VOC condensation and even nucleation. When the aim of the research is to study solid exhaust particles, this problem is typically handled with a dilution system that decreases the temperature and vapor pressures in two dilution stages including thermal treatment. However with low-emission vehicles this might also lower the particle concentration below instrument detection limit. Also, despite the controlled temperature profile dilution might still affect the size, composition and structure of particles, and uncertainty in dilution factor might decrease the measurement accuracy. To avoid these issues a new version of the Electrical Low Pressure Impactor ELPI+ was developed for high temperature, low concentration measurement. In this system the detector part, impactor, is heated to a high temperature up to 180C. This allows high temperature tailpipe aerosol measurement without dilution, without sample cooling and without VOC condensation. In other words, the particles are measured as they exist in the tailpipe. The system was tested with a 2-litre passenger car engine that was modified for natural gas fuel, known to produce very low particle emissions. In the test setup the exhaust gas composition was made adjustable by adding methane, propane, ethane and ethene to tailpipe-extracted side flow to mimic large bore engine (ship / power plant) emission composition. The developed High Temperature ELPI+ was used to measure the particle size distribution and concentration from tailpipe environment before catalysts. A two-mode particle size distribution was detected, one mode at below 10 nm particle size range and the other mode at around 30 nm. A volume-weighed distribution also shows a large particle mode at around 750 nm. In this presentation we describe the HT-ELPI+ and the engine and exhaust conditioning setup and present the particle measurement results from the system. We also discuss about the detected particles and their origin and present comparison results from other instruments that simultaneously measured diluted exhaust.

M3 - Conference article in proceedings

BT - Proceedings of the 25th Real-World Emissions Workshop

PB - CRC Press

ER -

Niemelä V, Lamminen E, Lehtoranta K, Rönkkö T. High temperature aerosol measurement: an alternative to dilution approach. In Proceedings of the 25th Real-World Emissions Workshop. CRC Press. 2015