Kinetics of Dehydroxylation and Decarburization of Coal Series Kaolinite during Calcination: A Novel Kinetic Method Based on Gaseous Products

Abstract

The analysis of gaseous products reveals the characteristics, mechanisms, and kinetic equations describing the dehydroxylation and decarburization in coal series kaolinite. The results show that the dehydroxylation of coal series kaolinite arises from the calcination of kaolinite and boehmite within the temperature range of 350–850 °C. The activation energy for dehydroxylation is 182.71 kJ·mol−1, and the mechanism conforms to the A2/3 model. Decarburization is a two-step reaction, occurring as a result of the combustion of carbon and the decomposition of a small amount of calcite. The temperature range in the first step is 350–550 °C, and in the second is 580–830 °C. The first step decarburization reaction conforms to the A2/3 mechanism function, and the activation energy is 160.94 kJ·mol−1. The second step decarburization reaction follows the B3 mechanism function, wherein the activation energy is 215.47 kJ·mol−1. A comparison with the traditional methods proves that the kinetics method utilizing TG-FTIR-MS is feasible.

Combustion Kinetics of Coal Treated by Microwave Irradiation Combined with Hydrochloric Acid Pickling

“…By referring to the infrared spectrum analysis literature. − The infrared absorption peaks of coal samples tested in this study are mainly on: 2903, 2830 cm –1 (mainly C–H groups); 1583, 1438 cm –1 (mainly O containing groups); and 1019 cm –1 (mainly −OH groups). As shown in Figure .…”

Effect on Combustion Properties of Coal Treated by Microwave Irradiation Combined with Sodium Hydroxide Solution

“…The FTIR spectra of the coal samples can be divided into four regions: 3600-3000 cm −1 (meanly -OH groups), 3000-2800 cm −1 (meanly aliphatic C-H groups), 1800-1000 cm −1 (meanly O containing groups) and 900-700 cm −1 (meanly aromatic C-H groups) [24,25].…”

“…The spectrums of three samples were similar on the whole, which meat that the basic macromolecular structure of coal sample were not changed significantly after treated. The FTIR spectra of the coal samples can be divided into four regions: 3600-3000 cm −1 (meanly -OH groups), 3000-2800 cm −1 (meanly aliphatic C-H groups), 1800-1000 cm −1 (meanly O containing groups) and 900-700 cm −1 (meanly aromatic C-H groups) [24,25].…”

“…With the increase of the concentration of sodium hydroxide solution used in the treatment of coal samples, the infrared spectra of the treated coal samples showed differences, especially the spectra of the coal samples treated with 20% sodium hydroxide solution showed obvious absorption peaks at 1433 cm −1 and 877 cm −1 , means that increase of O containing groups and aromatic C-H groups after treated. The FTIR spectra of the coal samples can be divided into four regions: 3600-3000 cm −1 (meanly -OH groups), 3000-2800 cm −1 (meanly aliphatic C-H groups), 1800-1000 cm −1 (meanly O containing groups) and 900-700 cm −1 (meanly aromatic C-H groups) [24,25].…”

Preparation of Calcined Kaolin by Efficient Decarburization of Coal-Series Kaolinite in a Suspended Bed Reactor

“…During the calcination of CSK, kaolinite decomposition and complex phase-transformation reactions occur [8,16]. These reactions overlap and interact with each other, so the calcination of CSK cannot be regarded as the combustion process of low-quality coal [21,22]. Therefore, an in-depth study of the mechanism and reaction kinetics of carbon removal from CSK is necessary to develop a high-efficiency calcination technology.…”