Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

Handle URI:
http://hdl.handle.net/10754/562349
Title:
Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement
Authors:
Lee, Junggil; Kim, Youngdeuk; Kim, Wooseung
Abstract:
Urea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC); Water Desalination & Reuse Research Cntr
Publisher:
Mary Ann Liebert Inc
Journal:
Environmental Engineering Science
Issue Date:
Oct-2012
DOI:
10.1089/ees.2011.0414
Type:
Article
ISSN:
10928758
Sponsors:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (2009-0077771).
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorLee, Junggilen
dc.contributor.authorKim, Youngdeuken
dc.contributor.authorKim, Wooseungen
dc.date.accessioned2015-08-03T10:01:56Zen
dc.date.available2015-08-03T10:01:56Zen
dc.date.issued2012-10en
dc.identifier.issn10928758en
dc.identifier.doi10.1089/ees.2011.0414en
dc.identifier.urihttp://hdl.handle.net/10754/562349en
dc.description.abstractUrea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.en
dc.description.sponsorshipThis research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (2009-0077771).en
dc.publisherMary Ann Liebert Incen
dc.subjectammoniaen
dc.subjectmixing chamberen
dc.subjectthermal decompositionen
dc.subjecturea-water solutionen
dc.titleDesign and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatementen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentWater Desalination & Reuse Research Cntren
dc.identifier.journalEnvironmental Engineering Scienceen
dc.contributor.institutionDepartment of Mechanical Engineering, Hanyang University, Seongdong-gu, Seoul, South Koreaen
dc.contributor.institutionDepartment of Mechanical Engineering, Hanyang University, 1271 Sa3-dong, Sangnok-gu, Ansan, Gyeonggi-do 426-791, South Koreaen
kaust.authorKim, Youngdeuken
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