Kinetic Parameters Of Samples Research Articles

Thermal and kinetic characteristics of the catalytic effect of different catalysts on the combustion of coal-char blends

Thermal and kinetic characteristics of the catalytic effect of CaO/MnO2/Fe2O3 on the combustion of coal-char blends were investigated with thermogravimetric analysis. Different characteristic parameters obtained from TG-DTG curves were used to determine the combustion characteristic of samples. A sectioning method was adopted to study the kinetics at the stage I and II of samples combustion. The kinetic parameters of samples were also determined according to the Coats-Redfern method. The experimental results indicated that, in stage I, the catalysts promoted volatile matter release and combustion decreased the ignition temperature; in stage II, the catalysts accelerated the combustion of fixed carbon in char. The ignition properties and the combustion properties all increased with catalysts addition. Fe2O3 and CaO exhibited effective catalytic effect on reducing the activation energy in the stage I and II of coal-char blends combustion. The catalytic effect of MnO2 in the stage II was not obvious. Therefore, Fe2O3 and CaO were considered having more catalytically active than MnO2 in coal-char blends combustion. [Received: May 30, 2018; Accepted: December 17, 2018]

Investigation of Lignite Combustion Characteristics with Thermal Analysis

Combustion characteristics of three types of lignite (coming from Indonesia, Ximeng, Hami), and a bituminous coal from Shenfu were studied by thermogravimetric analysis (TGA). Combustion parameters including characteristic temperatures, maximum rate of combustion, combustion performance index and activation energy of samples were analyzed. Kinetic parameters of samples were calculated using Jander model. The results showed that the characteristic temperatures of lignite samples are lower than that of bituminous coal. Indonesian lignite has the best combustion performance and the lowest activation energy. It indicates that high quality lignite such as Indonesian lignite has good combustion performance, even better than some bituminous coal, which makes it possible to use lignite by bulk combustion.

COD fractionation and parameter estimation for combined sewers by respirometric tests

AbstractThis paper evaluates the effects of the pipeline retention time in sewer systems and the dilution by stormwater runoff on COD fractions and kinetic parameters of samples from two large‐scale wastewater treatment plants (WWTPs) fed with combined sewers, one collected from adjacent residential areas (Sewer Q) and the other undergoing long pipeline transportation (Sewer B). With four batch tests, COD fractions and kinetic parameters of two sewers were obtained by numerical computation based on activated sludge models (ASMs) modified by a dual hydrolysis mechanism. Long pipeline transportation significantly influenced the content and existence of heterotrophic biomass fractions in sewers, and the percentage of the fraction in Sewer B (17%) was higher than that in Sewer Q (9%). Compared with Sewer Q, long pipeline retention also resulted in lower concentrations of hydrolysable fractions and particulate inert COD in Sewer B, as well as an increase in the hydrolysis rate coefficient of particulate hydrolysable COD from 0.90 day−1 in Sewer Q to 1.83 day−1 in Sewer B. Results of samples from Sewer B during a typhoon event showed high variations of COD fractions and parameters, indicating the necessity for COD fractionation and parameter calibration before applying ASMs to wet weather cases. Copyright © 2008 Society of Chemical Industry

Comparative kinetic analysis of raw and cleaned coals

In this research, thermogravimetry (TG/DTG) was used to determine the kinetic analysis of different coals and effect of cleaning process on kinetic parameters of raw and cleaned coal samples from Soma, Tuncbilek and Afsin Elbistan regions. Kinetic parameters of the samples were determined using Arrhenius and Coats and Redfern kinetic models and the results are discussed.