SiO_2对改性生物质焦理化特性的影响  

Influence of silica on physicochemical characteristic of modified bio-chars

作　　者：冯烨[1,2] 米铁[1] 张雄[2] 杨海平[2] 王贤华[2] 张世红[2] 陈汉平[2] 

机构地区：[1]江汉大学工业烟尘污染控制湖北省重点实验室,武汉430056 [2]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《农业工程学报》2014年第24期259-265,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家863计划课题(2012AA051803);江汉大学工业烟尘污染控制湖北省重点实验室开放课题(HBIK2014-01);国家自然科学基金项目(51276075)

摘　　要：为了探索SiO2对改性生物质焦理化特性的影响,以稻秆、棉秆、稻壳作为原料,在600℃下热解制备生物质焦;焦样再经不同温度下NH3/CO2高温气态改性后获得对CO2具有高选择性的富氮生物质焦。采用傅立叶红外光谱分析改性前后生物质焦的表面官能团结构,利用ASAP2020自动吸附仪测量其常温变压下的CO2吸附量,并结合X射线荧光光谱对热解焦的灰成分进行分析,探讨不同原料的生物质焦改性过程中,其理化特性的演变。研究表明,生物质焦灰分中过高的SiO2会阻碍其高温下CO2的活化作用及NH3的氨化作用;焦样灰分中的SiO2含量越低,其改性效果越理想。To study the effect of SiO2 on the physicochemical characteristic of modified biochar, bio-chars were obtained at 600℃ in a vertical furnace from a pyrolysis of rice straw, cotton stalk, and rice husk. Bio-chars were activated at different temperatures（400, 600, 800, and 1 000℃） in a gaseous NH3 and/or CO2 atmosphere. The variation of chemical properties, the CO2 adsorption capacities, and the physicochemical properties linked with an ash analysis of different raw chars and modified chars were investigated. An X-ray fluorescence（EARGE Ⅲ, EDAX Inc.） and an ion chromatograph（ICS-90, Dionex） were used according to the national standard of GB/T1574 to analyze the ash composition of pyrolytic biochars. The content of SiO 2 in rice husk char（87.47%） was the highest among the studied samples, followed by rice straw and cotton stalk chars, which were 51.99% and 18.21%, respectively. However, according to the proximate analysis of biomass raw materials, the proportion of ash in rice straw and rice husk was about 2-3 times of that of cotton stalk, therefore, the amount of SiO2 retained in rice husk and rice straw was nearly 15 times and 4-5 times of that in cotton stalk, respectively. The production and modification of biomass chars were carried out in a self-designed vertical furnace reaction system which included two parts： A gas generating zone and a modification reaction zone. The modification reaction zone mainly consisted of a stainless steel reactor（inner diameter 38 mm, outer diameter 40 mm, and height 600 mm） and a temperature programmed furnace.A Fourier transform infrared spectrum analyzer（VERTEX70, Bruker） was used to analyze the variation of chemical properties and surface functional groups of biochars before and after NH3 modification at different temperatures. And the Fourier transform infrared spectra of the corresponding biomass raw materials linked with a proximate and ultimate analysis were also presented to compare with that of chars and modified chars. The results showed

关 键 词：生物质 二氧化硅 物理特性 化学特性 富氮生物质焦 二氧化碳吸附 

分 类 号：TK16[动力工程及工程热物理—热能工程]