Urea thermolysis studied under flow reactor conditions using DSC and FT-IR

• The thermal decomposition of urea has been studied under flow reactor conditions using a differential scanning calorimeter (DSC) and Fourier transformed infrared spectroscopy (FT-IR). Samples of urea were administered using either a cordierite monolith impregnated with a urea/water solution or a silica cup with a dry urea sample. The samples were heated between 25 and 700 degrees C with heating rates of 10 and 20 K/min and the thermal response of the sample and off gas concentrations of ammonia and isocyanic acid were recorded. Biuret and cyanuric acid were decomposed in a separate set of experiments to verify some of the features observed in gas phase data during urea decomposition. Results show that depending on the way the sample is administered, i.e. cup or monolith different behavior in the evolved gases are observed. This is due to different reactions taking place in the vessel induced by the different conditions under which the pyrolysis of urea is preformed. (C) 2009 Elsevier B.V. All rights reserved.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Kemiska processer (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Chemical Process Engineering (hsv//eng)

Nyckelord

Urea decomposition

CYA

acid

Mass-transfer

selective catalytic-reduction

thermal-decomposition pyrolysis

Calorimeter

scr

catalysts

DSC

HNCO

Biuret

NH3

Heat transfer

nox reduction

FT-IR

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