Authors: N.I. Fedorova, I.Yu. Zykov

Title of the article: Influence of the rate of temperature rise at alkaline coal activation on the characteristics of sorbent porosity

Year: 2022, Issue: 2, Pages: 42-50

Branch of knowledge: 2.6.12. Chemical technology of fuel and high-energy substances

Index UDK: 662.742: 544.723.21

DOI: 10.26730/1999-4125-2022-2-42-50

Abstract: The relevance of the study is determined primarily by the fact that in order to determine the most efficient and economical methods for the preparation of carbon sorbents, data on the effect of varying various technological parameters on the properties of the resulting carbon materials are of great importance. The purpose of this study is the effect of the thermolysis temperature rise rate on the textural characteristics of sorbents obtained by chemical activation of coal in the presence of alkali. The object of study was coal of technological grade D, which is characterized by a low ash content (3.4%), a yield of volatile substances of about 43.3%, and a relatively low total sulfur content (0.3%). Thermogravimetric analysis found that an increase in the rate of pyrolysis temperature rise leads to an increase in the maximum rate of thermal decomposition (Vmax by more than 5 times) of the organic mass of the studied coal and the temperature (Tmax by 30°C) at which it is achieved. Carbon sorbents were obtained by the method of alkaline activation at a ratio of coal/KOH equal to 1/0.5 g/g at a temperature of 800°C, holding for 1 hour and various heating rates: 10°C/min, 30°C/min and in the thermal shock mode, when crucibles with a coal-alkali mixture were placed in a muffle furnace heated to 800°C. It is shown that with an increase in the heating rate, there is a tendency to an increase in the texture characteristics of the resulting sorbents. For example, when a coal-alkali mixture is activated at the highest rate of temperature rise, the value of the specific surface area increases by 20%. In this case, the application of the thermal shock mode leads to the formation of a more homogeneous carbon material in terms of the structure of the porous structure with a predominant share of microporosity with a predominant contribution of ultramicropores.

Key words: hard coal thermogravimetric analysis alkaline activation textural characteristics specific surface area porous structure

Receiving date: 24.02.2022

Approval date: 30.03.2022

Publication date: 29.04.2022

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