白云石催化成型松木的热解动力学研究

Research on pyrolysis dynamic of pine sawdust catalyzed by dolomite

以成型松木颗粒为原料和以白云石为催化剂进行热失重试验,研究升温速率和白云石的比例对成型松木颗粒的动力学影响。结果表明,随着升温速率(10,20,30,40 K/min)的增加,松木颗粒的失重率分别减少到19.06%,20.85%,22.97%,23.69%,但对最大微分热失重的影响较为明显,从-9.05%/min增加到-35.79%/min。在升温速率30 K/min下,加入10%,15%和20%的白云石,失重率从75.81%减少到73.64%,71.56%,并且在微分热失重曲线中的失重峰从2个增加到4个,第3个和第4个失重峰是由Ca(OH)_2和CaCO_3分解导致的。运用Coats-Redfern法求解在不同的升温速率和不同比例的白云石下松木颗粒的动力学参数发现,随着温度的增加,表观活化能和指前因子均在减少,分别从75.38 k J/mol、19.14 min^(-1)减少到71.15 k J/mol、17.10 min^(-1);随着白云石比例的增加,表观活化能和指前因子均在减少,分别从61.51 k J/mol、15.88 min^(-1)减少到48.56 k J/mol、13.14 min^(-1),表明提高升温速率和加入白云石能降低表观活化能,利于降低反应的能耗,提高生物质热解反应效率。

The influence of heating rate and proportions of dolomite as the catalyst on pine sawdust pyrolysis process and dynamics process are studied on the STA. The results show that increasing the heating rate( 10,20,30,40 K/min),pine sawdust weight loss rate reduces to 19. 06%,20. 85%,22. 97%,23. 69% respectively,but differential pyrolysis weight loss is more obvious form-9. 05%/min to-35. 79%/min. At the heating rate of30 K/min,the weight loss rate was reduced from 75. 81% to 73. 64% and 71. 56% after adding different proportions of dolomite,and the peak of differential pyrolysis weight loss was increased to four,which is due to the decomposition of Ca(OH)_2 and CaCO_3. The Coats-Redfern method was used to find the dynamic parameters of pine sawdust under different heating rate and dolomite ratio. With the increase of temperature,the apparent activation energy and pre-exponential factor were decreased from 75. 38 k J/mol,19. 14 min^(-1) to 71. 15 k J/mol,17. 10 min^(-1). With the increase of dolomite ratio,the apparent activation energy and pre-exponential factor decreased from 61. 51 k J/mol,15. 88 min^(-1) to 48. 56 k J/mol and 13. 14 min^(-1) respectively,which indicated that the growth of heating rate and the addition of dolomite could reduce the apparent activation energy and the reaction of energy and improve the efficiency of biomass pyrolysis.