코크스용 석탄의 탄화과정과 혼합탄과 Char의 관계에 대한 연구

Abstract

The current research was conducted to investigate the pyrolysis behavior of single and blended coking coals. In addition, this research also attempted to link the pyrolysis properties of blended raw coals with the reactivity of their chars with CO2. First of all, the coking coals industrially being used were selected, and nine blended cases with two kinds of coking coals were set up. The behavior of releasing gases, detecting mainly H2, CH4, CO and CO2, during pyrolysis were measured using Quadruple Mass Spectrometry (QMS) while 5 g of coals non-isothermally was heated at a rate of 5℃/min from room temperature to 1,000℃. The measurements of pyrolysis with each single coking coal were carried out, and then the pyrolysis results were formulated with the help of the Matlab program developed by Mathworks in terms of the curve fitting application. Then, the pyrolysis results of blended cases were predicted based on the formula of each single coking coal, and the measured pyrolysis results were compared with the prediction. The predictions were in good agreement with the actual results of pyrolysis experiments. It indicates it is possible to model pyrolysis pattern for raw coals. Subsequently, the pyrolysis activation energy of single coking coal and blended coals was evaluated with first order kinetic model, and the initiation temperature of releasing of H2 and CH4 was confirmed, which turned out to have relationship between initiation temperature and volatile matter of coking coals. Secondly, CO¬2 gasification measurement of chars made of single and blended coking coals was carried out using the thermogravimetric analyses (TGA) at various temperatures such as 1,000, 1,050, 1,100, 1,150 and 1,200°C to evaluate the activation energy of CO2 gasification with chemical and diffusion control models, respectively. The activation energy of CO2 gasification of chars made of single and blended coking coals showed specific relationship between single and blended coking coals. However, the relationship was not clear in some other cases. It means that the properties of the char were changed compared with the condition of raw coal.