Empirical correction of kinetic model for polymer thermal reaction process based on first order reaction kinetics

2020 ◽  
Author(s):  
Zhaoxiang Zhang ◽  
Fei Guo ◽  
Wei Song ◽  
Xiaohong Jia ◽  
Yuming Wang
Keyword(s):  
Kinetic Model ◽  
Reaction Kinetics ◽  
Thermal Reaction ◽  
Order Reaction ◽  
Reaction Process ◽  
First Order Reaction ◽  
First Order ◽  
Empirical Correction

Pre-Reduction of Chromite by Thermogravimetric (TG) Analysis

2013 ◽  
Vol 760 ◽  
pp. 23-32
Author(s):  
D.M.A. Khan
Keyword(s):  
Reaction Kinetics ◽  
Order Reaction ◽  
First Order Reaction ◽  
Reduction Mechanism ◽  
Muffle Furnace ◽  
Tg Analysis ◽  
First Order ◽  
Single Pellet ◽  
Reduction Smelting

Thermogravimetric experiments on prereduction of single pellet and multiple pellets were conducted in Muffle furnace at 1500oC. Reduction smelting of Chromite in Fe-C melt in TG setup indicates CR is reduced faster than CG and CB. The reduction mechanism takes the path of first order reaction kinetics. Only 50% Cr metallization could be obtained at 1550oC from the reduction smelting experiments.

On the Chemical Reactivity of the Phytochrome Chromophore in the Pr and Pfr Form

1985 ◽  
Vol 40 (3-4) ◽  
pp. 215-218 ◽  
Author(s):  
Fritz Thümmler ◽  
Peter Eilfeld ◽  
Wolfhart Rüdiger ◽  
Doo-Khil Moon ◽  
Pill-Soon Song
Keyword(s):  
Reaction Kinetics ◽  
Rate Constants ◽  
Chemical Reactivity ◽  
Order Reaction ◽  
First Order Reaction ◽  
Limiting Factor ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo First Order ◽  
The Difference

The reactivity of the phytochrome chromophore and related tetrapyrroles towards ozone and tetranitromethane was investigated. Both oxidizing reagents cause bleaching of the main absorp­tion band of the pigment. The rate constants for this bleaching were determined under conditions of pseudo first order reaction kinetics. The rate constants for the reaction with ozone are similar for native phytochrome and for freely accessible tetrapyrroles (biliverdin, small chromopeptides from phytochrome) indicating that accessibility is not the limiting factor for the reaction with ozone. Under a variety of conditions, the Pfr chromophore reacts by about 10% faster than the Pr chromophore. This may reflect the true difference in reactivity. The rate constants for the reaction with tetranitromethane are much larger for biliverdin, bilirubin and small chromopeptides from phytochrome than for native phytochrome. The limiting factor for this reaction in native phytochrome therefore is the accessibility of the chromophore by the reagent. Previous conclusions on the difference in exposure of the tetrapyrrole chromophore in Pr and Pfr are confirmed.

Interactions of hypochlorite ion and humic acid: photolytic and photocatalytic pathways

2001 ◽  
Vol 44 (5) ◽  
pp. 205-210 ◽  
Author(s):  
D. Gonenç ◽  
M. Bekbolet
Keyword(s):  
Humic Acid ◽  
Reaction Kinetics ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Acid Oxidation ◽  
First Order ◽  
Toc Removal

Photolytic and photocatalytic interactions of hypochlorite ion and humic acid are investigated under various conditions. Humic acid oxidation by aqueous chlorine under dark conditions are expressed in terms of first order reaction kinetics. Upon irradiation (300 nm < λ < 400 nm), photolysis of aqueous chlorine affect the removal efficiency of humic acid via oxidation. TiO2 sensitised photocatalytic oxidation conditions reveal an increase in the TOC removal rate of humic acid in the presence of aqueous chlorine. Under the specified conditions, increasing the photocatalyst loading up to 1.0 mg/mL markedly increase the TOC removal rate.

Development of Torrefaction Kinetics for British Columbia Softwoods

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Jianghong Peng ◽  
Xiaotao T. Bi ◽  
Jim Lim ◽  
Shabab Sokhansanj
Keyword(s):  
British Columbia ◽  
Weight Loss ◽  
Kinetic Model ◽  
Residence Time ◽  
Order Reaction ◽  
First Order Reaction ◽  
Chemical Components ◽  
First Order ◽  
One Step ◽  
Kinetics Of

Torrefaction is a thermal treatment without air or oxygen in the temperature range of 473-573 K. The pyrolysis kinetics of three chemical components (cellulose, hemicelluloses, and lignin) and wood at low temperatures of relevance to torrefaction conditions have been reviewed. A series of thermogravimetric (TG) experiments have been carried out to study the intrinsic torrefaction kinetics of major chemical components and British Columbia (BC) softwoods. The weight loss during BC softwood torrefaction was found to be mainly associated with the decomposition of hemicelluloses, although there was also certain degree of decomposition of cellulose and lignin. The weight loss of the BC softwoods during torrefaction could be approximately estimated from the chemical composition of wood species and the weight loss data for torrefaction of pure cellulose, hemicelluloses, and lignin, respectively. Based on the fitting of the TG curves of BC softwoods and three chemical components, two different torrefaciton models were proposed. The simple one-step (single-stage) kinetic model with the first order reaction can predict the reaction data reasonably well over the long residence time, with the final sample weight being strongly related to the torrefaction temperature. A two-component and one-step first order reaction kinetic model, on the other hand, gave improved agreement with data over short residence time, and can be used to guide the design and optimization of torrefaction reactors over the weight loss range of 0 to 40% at the temperature range of 533-573 K, which covers the typical range of industrially relevant operations.

Experimental Evaluation of Nonisothermal, First-Order Reaction Kinetics

1995 ◽  
Vol 28 (26) ◽  
pp. 8729-8734 ◽  
Author(s):  
D. J. Robbins ◽  
A. J. Almquist ◽  
D. C. Timm ◽  
J. I. Brand ◽  
R. E. Gilbert
Keyword(s):  
Reaction Kinetics ◽  
Experimental Evaluation ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order

Synthesizes and Properties Research of a Photochromic Diarylethene Bearing a Hexatomic Ring

2013 ◽  
Vol 830 ◽  
pp. 278-281
Author(s):  
Zhi Yuan Sun ◽  
Wei Wei Geng ◽  
Shou Zhi Pu
Keyword(s):  
Reaction Kinetics ◽  
Fluorescence Intensity ◽  
Uv Light ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Solid Films ◽  
Kinetics Of

A new photochromic diarylethene compound 1-(2-cyan-3-phenyl)-2-[5-(4-cyanobenzene) -2-methyl-3-thienyl] perfluorocyclopentene was synthesized. And their properties inculding photochromis, fluorescence in both hexane and solid films, reaction kinetics of cyclization and cycloreversion were studied. And its absorption maxima were observed at 539 nm in hexane and at 552 nm in PMMA films, respectively, upon irradiation with 313 nm UV light. The fluorescence intensity of diarylethene decreased upon irradiation with 313 nm UV light. Besides, the cyclization and cycloreversion processes of the compound were determined to be the zeroth and first order reaction by UV-Vis spectra, respectively.

Kinetics of polymeric substrate (dextrin or peptone) removal by activated sludge: hydrolysis of polymers to monomers is the rate-determining step

1997 ◽  
Vol 36 (12) ◽  
pp. 159-167 ◽  
Author(s):  
Yuu Ubukata
Keyword(s):  
Amino Acids ◽  
Activated Sludge ◽  
Reaction Kinetics ◽  
Removal Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Municipal Sewage ◽  
First Order ◽  
Rate Determining Step ◽  
Hydrolysis Of

Most of the organic compounds in primary effluent are polymers such as proteins and polysaccharides. However the bacteria present in activated sludge (AS) can only directly take up monomers such as amino acids and glucose which are produced from polymers by hydrolysis. Therefore, it is assumed that the hydrolysis of polymers to monomers by the bacteria is the rate-determining step in polymer removal. In this study, AS was acclimated to dextrin or peptone, and polymers (dextrin or peptone) and monomers (glucose or a mixture of free amino acids) were used as substrates for kinetic tests. The removal of monomers and polymers by the AS followed zero- and pseudo first-order reaction kinetics, respectively. The removal rate of monomers was higher than that of polymers, and the oxygen uptake rate of the AS during monomer removal was higher than that during polymer removal. One of the important differences between the polymers and monomers used in this study is whether glycosidic linkages or peptide bonds exist in the material. It was therefore verified that the hydrolysis of polymers to monomers by AS was the rate-determining step in polymer removal. The removal of polymers apparently followed first-order reaction kinetics at high F/M ratios, but nth-order reaction kinetics at low F/M ratios (n>1), which are commonly used in municipal sewage treatment.

Synethesis and Properties of 1-(2-trifluoromethylphenyl)-2-[2-methyl-5-(3-N,N-dimethylphenyl)-3-thienyperfluorocyclopentene

2013 ◽  
Vol 473 ◽  
pp. 77-80
Author(s):  
Zhi Yuan Sun ◽  
Dan Dan Xue ◽  
Shou Zhi Pu
Keyword(s):  
Reaction Kinetics ◽  
Fluorescence Intensity ◽  
Uv Light ◽  
Order Reaction ◽  
First Order Reaction ◽  
Fluorescent Properties ◽  
First Order ◽  
Kinetics Of

An unsymmetrical photochromic diarylethene 1-(2-trifluoromethylphenyl)-2-[2-methyl-5-(3-N,N-dimethylphenyl)-3-thienyperfluorocyclopentene (1a) was synthesized and its photochromism, fluorescent properties and reaction kinetics of cyclization and cycloreversion were studied in detail. The compound exhibited remarkable photochromism and its absorption maxima were observed at 552 nm in hexane and at 569 nm in PMMA films upon irradiation with 297 nm UV light. The fluorescence intensity of diarylethene decreased upon irradiation with 297 nm UV light. In addiation, reaction kinetics of the cyclization and cycloreversion processes of the compound were determined to be the zeroth and first order reaction by UV-Vis spectra, respectively.

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