Experimental study on production of semi-coke with coal slime using low-temperature pyrolysis technology

In order to gain a better understanding of coal slime low-temperature pyrolysis process and the effect on property of semi-coke produced by pyrolysis temperature and time,a study is made of the characteristics of low-temperature pyrolysis of coal slime,with an aim to bringing to light the low governing the low-temperature pyrolysis and determining the optimum process condition. Test result indicates that:the coal slime pyrolysis temperature lies in a range of 380~600 ℃,and a maximum pyrolysis rate can be achieved at a temperature of around 450 ℃; with the increase of temperature and time,the yield and contend of volatile matter of semi-coke tend to gradually decrease while the ash and fixed carbon content of semi-coke is seem to be gradually entiched; with the rise of temperature,the content of carbon tends to first lower down and then eventually go up with the increase of time; along with the ongoing pyrolysis process,the contents of nitrogen,hydrogen,oxygen,etc are gradually reduced while the content of moisture regained becomes gradually larger. At a pyrolysis temperatures of 450 ℃ and a time duration of 30 minutes,a best semi-coke product can be expected though low-temperature pyrolysis of coal slime: yield -85.54%; and ash content -29.3%; volatile matter -16.29%; fixed carbon -53.89%; and moisture regained -1.67%. As compared with the untreated slime,the moisture is reduced by 27. 07 percentage points,much beneficial to the enhancement of the calorific value of coal slime.