基于低温热解技术的煤泥制备半焦试验研究

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

为了进一步了解煤泥低温热解过程,考察热解温度和热解时间对煤泥半焦性质的影响,通过研究煤泥的低温热解特性,揭示其低温热解规律,并确定制备半焦的最优工艺条件。试验结果表明：煤泥的低温热解温度在380-600℃之间,热解温度在450℃左右时热解速率最大;随着热解温度和热解时间的增加,半焦的产率和挥发分逐渐降低,而其灰分和固定碳不断增加;随着热解温度的增加,半焦中的C含量呈先降低后增加的趋势,随着热解时间的增加,其含量逐渐增大;随着热解程度的增加,其中的N、H、O等元素含量逐渐降低,回吸水含量不断增加。在热解温度为450℃、热解时间为30 min的条件下,煤泥低温热解效果最好,半焦产率为85.54%、灰分为29.3%、挥发分为16.29%、固定碳为53.89%、回吸水含量为1.67%;与原煤性质相比,其水分下降27.07个百分点,这对提高其发热量十分有利。

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.