Statistical Modeling of the Effect of Rank, Temperature, and Particle Size on Low-Temperature Oxidation of Turkish Coals

Abstract

This paper aims to investigate the differences between the low-temperature oxidation behavior of some Turkish coals having different ranks by statistically analyzing the formation rates of CO 2 and CO as well as the ratio of CO/CO 2 . In order to do this, oxidation experiments were performed on four Turkish coals grouped at À425 þ 212, À212 þ 150, and À150 þ 106 lm size groups and oxidized at 40, 60, and 90 C, respectively. Then, a step-by-step multiple-regression analysis was conducted to assess the effect of rank, temperature, and particle size by determining the variation in the formation rates of CO and CO 2 as well as the ratio of CO/CO 2 over time for the data set obtained from the experiments. Regression results showed that as the rank increases the formation rates of CO and CO 2 it also increases the magnitude, and they decrease faster over time. The effect of temperature was clearly confirmed by the regression results as indicated by the temperature dummy, whereas the effect of particle size at close ranges of size groups was not clearly acquired.

Insights on the combustion and pyrolysis behavior of three different ranks of coals using reactive molecular dynamics simulation

“…This also agrees well with the previous experimental results. [10][11][12]46,47 The experimental and ReaxFF predicted rate of formation of CO and CO 2 is compared in Fig. 3(a) for CO and Fig.…”

“…The solid oxidation products are usually phenolic compounds which are separated from coal tar. [5][6][7][8][9][10][11] Coal with a higher oxygen content is expected to be more reactive towards gaseous oxygen and can produce a large amount of CO 2 and CO upon heating. 12 The heating rate of coal depends on the coal rank where the heating value is low for low rank coal.…”

“…The low-rank coal oxidizes at a high temperature, where the formation behaviour of CO and CO 2 were found to vary with temperature. [10][11][12][13][14][15][16][17] The hydrogen production rate is high for low-rank coal which gives a lower caloric value due to the loss of volatile components. 18,19 Therefore to understand the combustion phenomena, the chemical kinetics and thermodynamic models are important aspects.…”

Investigation of Spontaneous Combustion of Coal in Underground Coal Mining

“…The coal deposit is spread on a large area on West Toros Mountains of Turkey that is 620 km 2 . The temperatures changes of longwall for spontaneous combustion condition were measured by a temperature sensor placed inside the longwall.…”

“…Normally, if this heat is not removed from the surrounding air, after 70 o C, CO and CO 2 gases emissions are increased and after 125 o C water vapor are formed. If heat increase is continued, the coal combustion temperature is reached [1,2]. If necessary precautions are not taken for safety, hazardous gases are released inside the coal longwall [3,4].…”