尿素预处理玉米秸秆降解木质素动力学研究  

Delignification Kinetics of Corn Stover with Urea Pretreatment

作　　者：王忠江[1,2] 邹舰洋 曹振 王丽丽 刘卓[1] 李一博 WANG Zhongjiang;ZOU Jianyang;CAO Zhen;WANG Lili;LIU Zhuo;LI Yibo(College of Engineering,Northeast Agricultural University,Harbin 150030,China;Heilongjiang Key Laboratory of Technology and Equipment for the Utilization of Agricultural Renewable Resources,Harbin 150030,China)

机构地区：[1]东北农业大学工程学院,哈尔滨150030 [2]寒地农业可再生资源利用技术与装备黑龙江省重点实验室,哈尔滨150030

出　　处：《农业机械学报》2020年第11期321-328,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51406032);东北农业大学“学术骨干”项目(18XG15);中央引导地方科技发展专项(ZY17C05);黑龙江省博士后科研启动基金项目(LBH-Q19008)。

摘　　要：为探究尿素预处理玉米秸秆降解木质素的动力学特性,解析尿素对玉米秸秆木质素的作用规律,研究了总固体质量分数(10%、30%、50%和70%)和尿素添加比例(1∶100、1∶20、1∶10、1∶2和7∶10)对玉米秸秆木质素含量的影响,并进行模型拟合,获得了尿素预处理玉米秸秆降解木质素动力学模型。结果表明:总固体质量分数在50%以内时,随着尿素添加比例的增加,玉米秸秆的木质素去除率先增加、后降低,总固体质量分数为70%时木质素去除率随着尿素添加比例的增加而增加,当总固体质量分数为10%和70%、对应尿素添加比例为1∶20和7∶10时,获得的最大木质素去除率分别为71.05%、68.69%;不同预处理条件下,玉米秸秆的残余木质素质量与总固体回收量均呈现较好的线性关系,在整个尿素预处理过程中脱木质素选择性系数稳定在0.32~0.48 g/g之间;尿素预处理玉米秸秆的脱木质素过程符合初始脱木质素、大量脱木质素和残余脱木质素3个阶段连续一阶动力学模型,大量脱木质素阶段的最大可脱除木质素质量比可达0.71,在低、高总固体含量下,尿素转化的液态铵和气态氨对玉米秸秆均具有较好的脱木质素作用。Urea is easily dissolved in water and converted into gaseous ammonia or ammonium and bicarbonate ions under the catalysis of urease.The effects of total solids(10%,30%,50%and 70%)and ratios of urea to corn stover(1∶100,1∶20,1∶10,1∶2 and 7∶10)on residual lignin content of corn stover were studied systematically at 75℃to achieve the delignification kinetics of urea-pretreated corn stover,and the urea pretreatment characteristics of corn stover at different total solids were compared.The delignification kinetics characteristics of corn stover during urea pretreatment were fitted based on three first-order reactions.The first,second and third terms were based on the initial,bulk and residual phases of delignification,respectively.The results showed that the residual lignin content of ureapretreated corn stover was decreased as the ratio of urea to corn stover was increased firstly,reached minimum and then increased as the ratio of urea to corn stover was increased when total solids was less than 50%.In comparison,the residual lignin content of urea-pretreated corn stover was decreased as the ratio of urea to corn stover was increased during pretreatment with total solids of 70%.The two optimal lignin removal rates of 71.05%and 68.69%were achieved at total solids of 10%and 70%with urea to corn stover ratios of 1∶20 and 7∶10,respectively.A good linear relationship between the residual lignin content of urea-pretreated corn stover and the solid recovery yield was obtained under different pretreatment conditions.The delignification selectivity of urea-pretreated corn stover was stable at 0.32~0.48 g/g during pretreatment process.The delignification kinetics of urea-pretreated corn stover conformed to the three first-order models of initial,bulk and residual phases.The maximum delignification fraction of the bulk-phase reached up to 0.71.Therefore,the aqueous or gaseous ammonia converted from urea at low or high total solids were equally favorable for the delignification of corn stover.The results provided

关 键 词：尿素 玉米秸秆 木质素 动力学模型 

分 类 号：S216[农业科学—农业机械化工程]