摘要
Composition and formation cause of the deposits in diesel engine urea-SCR system were investigated with the help of Fourier transform infrared (FTIR) spectrometer and thermal gravimetric (TG) analyzer. Deposits samples were respectively taken from places near the urea nozzle and on the exhaust pipe wall. Results indicate that the two samples of deposits decompose into gas when heated to above 430℃; There are two weight loss stages on the former TG curve in range of 150℃ to 250℃ the sample decomposes into isocyanic acid and ammonia; and in range of 280℃ to 360℃ it decomposes mainly into isocyanic acid. The latter loses its weight mostly in range of 320℃ to 400℃ and decomposes into isocyanic acid. The former is mainly blend of unreacted urea and biuret and cyanuric acid resulted from insufficient thermal decomposition of urea in low temperature and lack of air flow disturbance conditions. The latter is mainly the cyanuric acid, formed by sprayed urea adhering on wall in low temperature and low exhaust flow conditions, or generated directly by isocyanic acid high temperature polymerization.
| 源语言 | 英语 |
|---|---|
| 页（从-至） | 1-6 |
| 页数 | 6 |
| 期刊 | Neiranji Gongcheng/Chinese Internal Combustion Engine Engineering |
| 卷 | 35 |
| 期 | 6 |
| 出版状态 | 已出版 - 15 12月 2014 |