不同温度下棉杆颗粒热解制炭的性能研究

A study of performance of biochars pyrolyzed from cotton stalk pellet at varied pyrolysis temperatures

为了考察不同热解温度下制备的棉杆颗粒炭(CSPB)的理化性能,评价其农业、工业等不同领域的应用价值和最佳工艺条件.分别采用FTIR分析、元素及工业分析、燃烧测试方法对热解温度在300℃、400℃、450℃、500℃、600℃下制备的CSPB的官能团、元素含量、表观特性及燃烧性能进行研究.结果表明,随着热解温度的升高,CSPB中羟基、脂肪族C-H键、羰基、醚类C-O键等含量逐渐减少,芳香族C=C键逐渐增多,与粉末炭相比其波数在2 000 cm1以下的官能团峰值较大.热解温度对CSPB的性能影响显著,高温颗粒炭有较高的碳含量、固定碳含量、p H值、导电性和持水量,但其跌落强度、质量得率、能量得率、固定碳得率均相对较低,且高温颗粒炭的灰分大、着火点较高.综合考虑450℃热解温度下制备的CSPB性能较好,适用于颗粒活性炭、固体燃料等二次加工产品.

In order to study the physical and chemical property of cotton stalk pellet biochars （CSPB） prepared at varied pyrolysis temperatures and evaluate its application values and optimum conditions in agricultural, industrial and other different fields. The functional groups, element contents, apparent characteristics and combustion performances of CSPB prepared at different pyrolysis temperatures of 300 ℃, 400 ℃, 450 ℃, 500 ℃, 600 ℃ were investigated with the FTIR analysis, ultimate and proximate analysis and combustion test. The results indicate that, with the increase of pyrolysis temperature, the contents of hydroxyl, aliphatic C-H bonds, carbonyl and ethers C-O bonds in the CSPB decreased, while the aromatic C=C bonds increased gradually and the peak values of CSPB functional groups under the wave number 2 000 cm^-1 were relatively larger compared with powder biochars. In addition, the effect of pyrolysis temperature of the performance of CSPB was significant and the carbon content, fixed carbon content, PH, conductivity and water holding capacity of high-temperature pellet biochars were relatively high, but its dropping strength, mass yield, energy yield and fixed carbon yield were relatively low while its content of ash and ignition point were relatively high. By considering comprehensively, the performance of CSPB prepared at pyrolysis temperature 450 ℃ was better for granular activated carbon, solid fuel and other secondary processing products.