Thermodynamics and reaction mechanism of urea decomposition

被引：130

作者：

Tischer, Steffen ^{[1
]}

Boernhorst, Marion ^{[2
]}

Amsler, Jonas ^{[2
]}

Schoch, Guenter ^{[2
]}

Deutschmann, Olaf ^{[1
,2
]}

机构：

[1] KIT, Inst Catalysis Res & Technol IKFT, Karlsruhe, Germany

[2] KIT, Inst Chem Technol & Polymer Chem ITCP, Karlsruhe, Germany

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2019年 / 21卷 / 30期

关键词：

THERMAL-DECOMPOSITION; STANDARD ENTHALPIES; WATER-SOLUTION; BIURET; SOLUBILITY; PYROLYSIS; HYDROLYSIS; REDUCTION;

D O I：

10.1039/c9cp01529a

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The selective catalytic reduction technique for automotive applications depends on ammonia production from a urea-water solution via thermolysis and hydrolysis. In this process, undesired liquid and solid by-products are formed in the exhaust pipe. The formation and decomposition of these by-products have been studied by thermogravimetric analysis and differential scanning calorimetry. A new reaction scheme is proposed that emphasizes the role of thermodynamic equilibrium of the reactants in liquid and solid phases. Thermodynamic data for triuret have been refined. The observed phenomenon of liquefaction and re-solidification of biuret in the temperature range of 193-230 degrees C is explained by formation of a eutectic mixture with urea.

引用

页码：16785 / 16797

页数：13

共 37 条

[1]

[Anonymous], 2017, ICSC DAT

[2]

[Anonymous], 2013, VDI WARMEATLAS MIT 3

[3] Hydrolysis and thermolysis of urea and its decomposition byproducts biuret, cyanuric acid and melamine over anatase TiO2 [J].

Bernhard, Andreas M. ;

Peitz, Daniel ;

Elsener, Martin ;

Wokaun, Alexander ;

Kroecher, Oliver .

APPLIED CATALYSIS B-ENVIRONMENTAL, 2012, 115 :129-137

[4] Modeling and simulation of the injection of urea-water-solution for automotive SCR DeNOx-systems [J].

Birkhold, Felix ;

Meingast, Ulrich ;

Wassermann, Peter ;

Deutschmann, Olaf .

APPLIED CATALYSIS B-ENVIRONMENTAL, 2007, 70 (1-4) :119-127

[5] Characterization of solid deposits from urea water solution injected into a hot gas test rig [J].

Boernhorst, M. ;

Langheck, S. ;

Weickenmeier, H. ;

Dem, C. ;

Suntz, R. ;

Deutschmann, O. .

CHEMICAL ENGINEERING JOURNAL, 2019, 377

[6] Single droplet impingement of urea water solution on a heated substrate [J].

Boernhorst, M. ;

Deutschmann, O. .

INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, 2018, 69 :55-61

[7] Solubility and reactivity of HNCO in water: insights into HNCO's fate in the atmosphere [J].

Borduas, N. ;

Place, B. ;

Wentworth, G. R. ;

Abbatt, J. P. D. ;

Murphy, J. G. .

ATMOSPHERIC CHEMISTRY AND PHYSICS, 2016, 16 (02) :703-714

[8] Kinetic modeling of urea decomposition based on systematic thermogravimetric analyses of urea and its most important by-products [J].

Brack, Wolfgang ;

Heine, Barbara ;

Birkhold, Felix ;

Kruse, Matthias ;

Schoch, Guenter ;

Tischer, Steffen ;

Deutschmann, Olaf .

CHEMICAL ENGINEERING SCIENCE, 2014, 106 :1-8

[9]

Burcat A., Burcat's Thermodynamic Data, Laboratory for Chemical Kinetics

[10]

Dean J.A., 1985, LANGES HDB CHEM, V13

← 1 2 3 4 →