玉米秸秆棒状燃料热解过程和产物特征研究

以玉米秸秆棒状燃料为原料,在固定床反应器上探究热解温度对玉米秸秆棒状燃料热解过程和热解产品性质的影响。研究发现,随着热解温度的升高,热解气体产量增加,固体炭产量逐渐减少,生物油产量先增后减在450℃时达到最大值35.61%。对固体炭进行工业分析,发现其灰分含量较高;FT-IR分析表明:玉米秸秆棒状燃料的热解反应主要发生在650℃之前;SEM图显示断截面表现为蜂窝状的孔结构。生物油的GC-MS分析表明:在250~750℃下生物油的组成主要是呋喃、酮、醛和酚类等含氧化合物,其中酚类和呋喃类化合物是含量最多的物质;而在850~950℃下以多环芳烃类化合物为主。热解气的主要组成是CO₂、CO、CH₄和H₂,同时有少量的C₂H_n化合物,在250~450℃范围内,气体的主要组成是CO和CO₂,随着温度升高,CO、H₂、CH₄和C₂H_n逐渐增加,热解气的热值逐渐增加,在650℃下气体产品的热值已达到13.05 MJ/m³,当温度大于650℃后,热值增加速率变慢。

Pyrolysis Process of Corn Stalk Briquettes and Characteristics of Products

The pyrolysis of corn stalk briquette in a fixed bed was investigated.The influences of pyrolysis temperature on the pyrolysis process and the properties of products (solid charcoal,bio-oil and gaseous product) were studied,too.The research found that with the increase of the pyrolysis temperature,the yield of solid charcoal decreased,and the production of gaseous product increased.The bio-oil yield firstly increased and then decreased with the maximum of 35.61% at 450℃.The proximate,FT-IR and SEM analyses of solid charcoal showed that the charcoal had high ash content,the pyrolysis reaction of corn stalk briquette occuried mainly before 650℃ and the pore structure was honeycomb on the broken section.The GC-MS analyses of bio-oil showed that at low temperature (250-750℃),the organic compounds identified from pyrolysis bio-oil mainly included many oxygenated compounds such as aldehydes,ketones,furans and phenols;the phenolic compounds and furans were most abundant compounds.Nevertheless, the major compounds in the pyrolysis bio-oil obtained at higher temperatures (850-950℃) were polycyclic aromatic hydrocarbons (PAHS).The main compositions of gaseous product were CO₂,CO,H₂,CH₄and a spot of C₂H_n.In the temperature of 250-450℃,the high proportion in gaseous were CO and CO₂.With the increase of temperature,the productions of CO, H₂, CH₄ and C₂H_n increased,then the calorific value of gaseous product increased.At 650℃,the calorific value of the pyrolysis gas had reached 13.05 MJ/m³ and the rate of increasing slowed down when temperature exceed 650℃.