Thermogravimetric Studies on the Kinetics of N2O-Char Reaction

• Main Authors: Hsieh,Ya Sheng, 謝雅聖
• Other Authors: Teng,Hsi Sheng
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/25909934138114582979

碩士 === 中原大學 === 化學工程研究所 === 84 === The heterogeneous reduction of N2O by carbon was studied in a thermogravimetric analysis system, employing pseudosteady reaction method. The reactions were carried out at temperatures from 673 to 923 K, and at N2O partial pressures in the range of 10.1-101kPa.A relatively pure carbon derived from phenolic res- in was used, and the heat treatment temperatures are 1223 and 1323K.The N2O-carbon reaction can be divided into two temperat- ure regimes.The change of reaction activation energy implies the reaction is controlled by different mechanisms in different temperature regimes.The reaction order with respect to N2O pre- ssure is not constant. It was found that the reaction order be- come negative when the N2O pressure is higher . The results su- ggest the increased formation of C(N2O)m complexes at higher N2 O pressures to hinder the reaction . As a comparison,the carbon was gasifide in O2 at temperature between 573 and 673K and O2 pressures in the reange of 10.1-101 KPa.The activation energy and reaction order with respect to O2 pressures are 130 KJ/mole and 0.64, respecivly . Surface structrues of the carbons gasified in N2O and O2 are different . Higher surface area is developed for carbon gasifi ed in O2 than in N2O.The carbon reactivity, based on perunit su rface area of the carbon , in O2 remains relativly constant at various extents of burn-off .Howeraver, the reactivity in N2O decraeases with the increase of the burn-off level.