松木屑加压CaO催化热解动力学研究

摘要

The influences of different pressures, heating rate and addtion of CaO catalyst on pine sawdust pyrolysis process and dynamics analysis were studied. The experimental results show that:1 ) Increasing the reaction pressure will reduce eventually weight loss rate of pyrolysis process, and the final remaining material will increase, increasing the reaction pressure is not conducive to the volatile analysis. This study found that a certain range of pressure increase can reduce the activation energy of pyrolysis process, which is advantageous to the pyrolysis reaction, but after the pressure exceeds 0. 7 MPa, activation energy began to increase. 2 ) Increasing the heating rate can enhance the volatile releases, which is advantageous to the pyrolysis reaction, but a large amount of precipitation temperature rang of volatile was not obvious. It was found that with the increase of heating rate, the reaction activation energy trendth decrease. It shows that with the increase of heating rate, pine sawdust pyrolysis reaction is more intense. 3) Addition of CaO in the pine sawdust, has a larger effect on pyrolysis reaction process. With the increase of CaO catalyst additives, pine sawdust weight loss rate reduces gradually from 72. 81% to 59. 61 %. Total reduction is 18. 13 %. DTG curves show that weight loss peaks increased to four,the other two peaks are the decomposition weight loss caused by Ca( OH) 2 and CaCO3 , respectively. With the increase of addition of CaO, the first and second peaks of weight loss peak decreases gradually. The temperature corresponding to the peak point of the biggest change is not obvious. The third and fourth weight loss peaks increase gradually, and the maximum peak corresponding to the temperature appears obvious trend of increase.%研究了不同压力、升温速率以及添加CaO催化剂对松木屑热解过程的影响并进行了动力学分析。研究结果表明：1)增加系统的反应压力会降低热解过程的最终失重率，最终的剩余物质增加，并且提高反应压力，不利于挥发分析出。但是通过动力学分析发现，一定范围内增加压力能够降低热解过程中的活化能，从而有利于热解反应的发生，但是压力超过0.7 MPa以后，活化能开始增加。2)增加升温速率，挥发分释放的越强烈，有利于热解反应的进行，但挥发分大量析出的温度范围并没有很明显的浮动。通过动力学分析发现，随着升温速率增加，反应的活化能出现减少趋势，这说明随着升温速率增加，松木屑热解反应更加激烈。3)在松木屑热解反应中添加CaO对反应过程有较大的影响。随着CaO催化剂添加量增加，松木屑最终失重率逐渐减少，从72.81%减少到59.61%，降幅达到18.13%。 DTG曲线显示失重峰增加到4个，另外两个为Ca( OH)2和CaCO3分解所引起的失重峰。随着CaO添加量的增加，第1个失重峰的峰值和第2个失重峰的峰值逐渐减小，最大峰值对应的温度点变化不明显；第3、第4个失重峰的峰值逐渐增加，最大峰值对应的温度出现明显增加趋势。