Comparison of techniques for the gas phase analysis of ammonia and nitrogen oxides in Diesel exhaust gases

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Renewable energies Eco-friendly production Innovative transport Eco-efficient processes Sustainable resources 8th International Conference on

in Diesel exhaust gases Edwin Zam 1, Anne Jaecker-Voirol 1, Philippe Mirabel 2 1 IFPEN 1 & 4 Avenue de Bois Préau -92852 Rueil-Malmaison Cedex,

1 Renewable energies Eco-friendly production Innovative transport Eco-efficient processes Sustainable resources 8th International Conference on Air Quality, Science & application Athens, March 19 23, 212 Comparison of techniques for the gas phase analysis of ammonia and nitrogen oxides in Diesel exhaust gases Edwin Zam 1, Anne Jaecker-Voirol 1, Philippe Mirabel 2 1 IFPEN 1 & 4 Avenue de Bois Préau Rueil-Malmaison Cedex, France ( 2 LMSPC, UMR CNRS-UdS 7515, 1 rue Blessig, 6784 Strasbourg Cedex, France ( )

The measurement challenge Selective Catalytic Reduction (SCR) is a promising technology to reduce nitrogen oxides (Nx) of Diesel passenger car Heavy duty Diesel are already equipped with SCR Purpose

2 The measurement challenge Selective Catalytic Reduction (SCR) is a promising technology to reduce nitrogen oxides (Nx) of Diesel passenger car Heavy duty Diesel are already equipped with SCR Purpose of the project To analyse the nitrous compounds produced during the SCR process in purpose to calibrate SCR. Diesel exhaust gas (NH 2 ) 2 C NH 3 + HNC NH 3 + C 2 SCR catalyst Exit of exhaust components: nitrogen, water, carbon dioxide NH 3 HNC Nx N 2 many side reactions occur & interfere an accurate technique for analyzing NH 3 is essential for controlling the calibration of SCR Improvement of the analysis: to improve the measurement in response time and in quantification Improvement of the sampling system: to obtain a good precision on the analysis (material, temperature, geometry of the sampling lines ) 2

The measurement challenge To study the measurement system Study the different analyser Study the sampling conditions Modelling the sampling system Nx & NH 3 measurement in exhaust gas

Infrared) n heavy Diesel trucks, the legislation Euro VI plans to use the diode laser and FTIR analysers to measure NH 3.

3 The measurement challenge To study the measurement system Study the different analyser Study the sampling conditions Modelling the sampling system Nx & NH 3 measurement in exhaust gas bjectives: to compare 2 different analysers for measurement in the exhaust pipe of a Diesel passenger car equipped with a SCR: FTUV (Fourier Transform Ultraviolet) FTIR (Fourier Transform Infrared) n heavy Diesel trucks, the legislation Euro VI plans to use the diode laser and FTIR analysers to measure NH 3. However this legislation does not plan to calibrate the SCR technology First step: to measure in real conditions on a passenger car with instruments commercially available FTUV FTIR Measurements comparison of : N, N 2 and NH 3 at the exit of the exhaust pipe 3

Vehicle Roller test bench What is a roller test bench?

Strategy To measure under realistic conditions: Measurement on a vehicle equipped with a

of in excess SCR Injection coefficient : α= [NH ]/[Nx] 3 Sample line + filter Sample line

4 Vehicle Roller test bench What is a roller test bench? roller ventilation Speed variations are imposed for measuring the emissions of pollutant Strategy To measure under realistic conditions: Measurement on a vehicle equipped with a prototype IFPEN -SCR system Measurement of NH 3 in the pipe line: Exhaust gas injection of in excess SCR Injection coefficient : α= [NH ]/[Nx] 3 Sample line + filter Sample line + filter Gas Evacuation FTUV 2L/min FTIR 5L/min Tests in realistic conditions with injection: on steady-state operating points 4

5 Results & discussion Measurement of N downstream of the SCR catalyst FTUV 2L/min N (ppm) - FTIR/FTUV 8 4 FTIR-N FTUV-N Multigas analyser-n2 alpha- Injection coefficient : α= [NH 3 ]/[Nx] alpha FTIR - N (ppm) SCR Correlations plots of N y =,9x + 6,3 R 2 =,9 FTIR 5L/min NH 3 HNC Nx N Time (s) Urea injection Absence of N Urea injection Absence of N FTUV - N (ppm) The measurement of FTUV is better but globally we have a correlation of N of.9. Most of the time we have a good agreement between the responses of the 2 analysers for N

6 Results & discussion Measurement of N2 downstream of the SCR catalyst FTUV 2L/min SCR FTIR 5L/min 8 FTIR-N2 FTUV-N2 2 NH 3 HNC Nx N 2 N2 (ppm) - FTIR/FTUV 4 Urea injection X 2,6 Multigas analyser-n2 alpha time (s) 1,5 1,5 alpha FTUV: Problem in quantification : Absence of an adapted calibration gas and low detection limit Remedial factor of about 2,6 for the FTUV concentration measurement 6

7 Results & discussion Measurement of NH3 downstream of the SCR catalyst FTUV 2L/min SCR FTIR 5L/min NH3 (ppm) FTIR/FTUV FTUV-NH3 FTIR-NH3 alpha - Urea injection Delay of 1 min between FTUV & FTIR answers Time (s) 2 1,5 1,5 alpha Time delay of 1 minute: Importance of the real-time measurement for the SCR calibration NH 3 HNC Nx N 2 7

8 Results & discussion Measurement of NH3 upstream of the SCR catalyst FTIR 5L/min SCR NH 3 HNC 2 16 FTIR-NH3 alpha - ~ 3 s 2 1,5 (NH 2 ) 2 C NH 3 + HNC NH 3 + C 2 Nx N 2 8 NH3 (ppm) FTIR Urea injection ~ 1min ~ 3 s Time (s) 1,5 alpha Even just after the injection, there is a time delay of about 3-6 sec for the FTIR signals of NH3 Time delay due to decomposition and retention inside the exhaust line

9 Results & discussion N K for FTUV & FTIR N2 problem in quantification for FTUV (calibration) NH3 K good agreement between the two analysers but the response time has to be clearly improved FTIR brings extra information onproducts of the decomposition with a response time in adequationwith the emission of the pollutants in real time Such as: HNC N2 HCN FTIR 5L/min SCR NH 3 HNC Nx N 2 9

10 FTIR - NH3/HNC (mol) Results & discussion Measurement of HNC upstream of the SCR catalyst,1,8,6,4,2 FTIR-HNC FTIR-NH3 alpha- HNC NH 3 1,2,8,4 alpha FTIR 5L/min Decomposition scheme of HN H 2 N NH 2 + NH 3 SCR thermolysis hydrolysis isocyanic acid H 2 ammonia C 2 + NH 3 carbon dioxide NH 3 HNC Nx N 2 ammonia time (s) According to the decomposition scheme of, the quantity of NH 3 should exceed that of the HNC. But measured HNC concentrations are about x2 of NH 3 concentrations. Problem in quantification (it was not possible to calibrate the FTIR for HNC) 1

11 Conclusions & outlooks Performance of the analysers? What FTIR brings more? FTIR & FTUV performs well for N & NH3 measurement. FTUV had presented a bad detection forn2 (problem in calibration). FTUV is less bulky (more easy to install inside an engine test cell) and is 5 times less expensive than the FTIR and make it possible to obtain good results if the calibration problem for N2 is solved. FTIR brings extra information on decomposition products But we could observe problems in quantification. FTIR is provided with a factory calibration. And it is difficult to calibrate on such gases as HCN and HNC because of their toxicity. What has been observed for NH3 in particular? Adsorption/desorption phenomena has been observed for NH3 depending on length, material, temperature or on the presence of cold points in the sample lines, clogging of the sampling system and material of the filters. 11

12 Conclusions & outlooks What about NH3 legislation? Currently, NH3 is not regulated by the legislation. But NH3 will probably be regulated for the next legislation after Euro 6 (?). As the heavy duty Diesel are already equipped with the SCR technology, NH3 is regulated in the heavy trucks legislation Euro VI. But for the development of a -SCR system we will need: Information with a response time compatible with real-time measurements on standardized cycles In our study we succeed in comparing two different analysers on the measurement of N, N2, NH3 at the exhaust of a Diesel passenger car on steady-state points. ur study shows the difficulty to obtain a real-time measurement and to obtain an exact quantification. Improvements are necessary in both fields. Future works will be focused on the study of an efficient sampling systemto minimize the response time. 12

13 Acknowledgement IFPEN& CNRS for financial support Arnaud Frobert, Mickael Leblanc & Pascal Hayrault (IFPEN) for vehicle test on roller bench & measurement on analysers All the members of powertrain team IFPEN Lyon (R15) & Rueil (R14/11) Partnerships 13

14 Thank you for your attention!!! Contacts : edwin.gallino-zam@ifpen.fr anne.jaecker@ifpen.fr 14

15 Renewable energies Eco-friendly production Innovative transport Eco-efficient processes Sustainable resources

Context and bjectives In 29, the most significant source of NX emissions were the Road transport sector (38%) in Europe In Europe, Percentage of diesel cars has increased between 1995 and 29.

16 Context and bjectives In 29, the most significant source of NX emissions were the Road transport sector (38%) in Europe In Europe, Percentage of diesel cars has increased between 1995 and 29. Source: European Environment Agency (EEA) % of diesel cars in the total passenger car fleet Greece Sweden Lithuania Slovenia Poland Hungary Estonia Denmark Finland Norway Ireland Netherlands United Kingdom Czech Republic Germany Portugal Italy Turkey Bulgaria Spain Austria France Belgium Luxembourg % 1% 2% 3% 4% 5% 6% 7% 16

Emissions per capita and GDP

Emissions per capita and GDP (1990 -) CEIP Centre on Emission Inventories and Projections Emissions per capita and emissions per GDP were calculated for all years from 1990 to where data was available