Based on the principle of the pyrolysis,the slow pyrolysis characteristic of corn straw was analyzed through the methods of thermogravimetry and tube furnace pyrolysis sampling.It is considered that temperature is an important factor in the pyrolysis process,the heating rate (20℃/min,30℃/min,40℃/min,50℃/min,60℃/min) and final pyrolysis temperature (300 ℃,400 ℃,500 ℃,600 ℃,700 ℃) were adopted as the influencing factors,the yield of pyrolsis products (including carbon residue,biomass tar and pyrolysis gas) were used as the analysis index,as well as the pyrolysis gas composition was analyzed.The results show that with the increase of heating rate (20~60 ℃/min),the yield of carbon residue and gas yield are slightly changed,and the yield of tar is improved greatly from 12% to 18%.When the final temperature is 600 ℃,the tar yield reaches a maximum peak value,and the highest value reaches 18%.Before the peak temperature,the yield of tar could be increased with the increased final temperature.When the final temperature was higher than the peak temperature,the yield of tar will be reduced soon.The productivity of gas and heat value could be increased with the increased temperature,the low calorific value is 10.22 MJ/Nm3 at 700 ℃.%热解终温和升温速率是玉米秸秆热解的重要影响因素.基于玉米秸秆慢速热解原理,采用热重和管式炉热解取样方法对玉米秸秆的慢速热解特性进行实验分析.取升温速率(20 ℃/min,30 ℃/min,40 ℃/min,50 ℃/min,60 ℃/min)和终温(300 ℃,400 ℃,500 ℃,600 ℃,700 ℃)作为影响因素,以热解产物(残炭、生物质焦油和热解气体)的产率作为评价分析指标,并对不同终温条件下的热解气体成分进行定量分析.试验结果表明,随着升温速率的增加(20~60 ℃/min),残炭产率和气体产率略有变化;而焦油产率有较大幅度的提升,可从12%提升至18%.热解终温的升高,使固体残渣中的挥发分进一步析出,残炭产率下降;终温为600 ℃时,焦油产率达到极大峰值,最高可达18%,峰值温度前,焦油产率随终温的增加而增加,当终温大于峰值温度后,焦油产率迅速减少;气体产率随温度的升高而增加,热值也随之增加,在700 ℃时,低位热值为10.22 MJ/Nm3.
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