SCR系统尿素沉积物重要组分试验研究

莫春兰; 龙华林; 莫益涛; 邱崇桓; 江明儒; 黄福川

车用发动机 ›› 2021, Vol. 0 ›› Issue (2) : 76-81.

栏目

SCR系统尿素沉积物重要组分试验研究

莫春兰，龙华林，莫益涛，邱崇桓，江明儒，黄福川

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Experimental Study on Important Components of Urea Deposits for SCR System

MO Chunlan,LONG Hualin,MO Yitao,QIU Chonghuan,JIANG Mingru,HUANG Fuchuan

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文章历史 +

摘要

为减少柴油机SCR系统尿素喷射沉积物的生成，对尿素沉积物成分、含量及生成进行了升温速率为10 ℃/min的热重试验研究。结果表明，尿素沉积物主要由缩二脲、三聚氰酸及其同系物组成，尿素热解过程生成的异氰酸引发各沉积物的生成，异氰酸未充分水解是尿素沉积物生成的的重要条件；尿素或缩二脲发生副反应都可生成三聚氰酸及其同系物，其中缩二脲是关键物质；三聚氰酸在热解过程中产生少量副产物，三聚氰酸一酰胺及三聚氰酸二酰胺是生成耐高温产物的主要反应物。尿素沉积物中缩二脲质量占比约20%，三聚氰酸质量占比约60%，三聚氰酸同系物质量占比约20%。本试验结果可为尿素沉积物的生成反应动力学机理完善及其生成预测提供参考依据。

Abstract

In order to reduce the urea spray deposits for the SCR system of diesel engine, thermogravimetric tests were conducted at a heating rate of 10 ℃/min to analyze the composition, content and formation of urea deposits. The results show that the urea deposits are mainly composed of biuret, cyanuric acid and their homologues. The generated isocyanic acid triggers the formation of various deposits and its insufficient hydrolysis is an indispensable condition of urea deposits. Cyanuric acid and its homologues can be generated by side reactions of urea or biuret, in which biuret is the key substance. Cyanuric acid produces a small amount of byproducts in its pyrolysis process. Ammelide and ammeline are the main reactants to produce high temperature resistant products. About 20% mass proportion of urea deposits is biuret, about 60% is cyanuric acid and about 20% is cyanuric acid homologues. The test results provide a reference for the improvement of reaction kinetic mechanism and formation prediction of urea deposits.

导出引用

莫春兰，龙华林，莫益涛，邱崇桓，江明儒，黄福川. SCR系统尿素沉积物重要组分试验研究[J]. 车用发动机. 2021, 0(2): 76-81

MO Chunlan,LONG Hualin,MO Yitao,QIU Chonghuan,JIANG Mingru,HUANG Fuchuan. Experimental Study on Important Components of Urea Deposits for SCR System[J]. Vehicle Engine. 2021, 0(2): 76-81