摘要
为了提高稻秸的可生物降解性,利用尿素氨化预处理方式,研究不同尿素质量分数（2%、4%、6%、8%、10%）和不同预处理温度（25、30、35、40、45、50℃）对稻秸预处理前后木质纤维素含量变化及干发酵产气特性的影响。结果表明：1）不同尿素质量分数对稻秸预处理效果影响显著,尿素预处理能够破坏稻秸木质纤维素的结构,预处理后稻秸的碳氮比降低,预处理后稻秸的累计产气量比未经处理组高20.67%~38.20%（P〈0.05）,尿素质量分数为4%时效果较好;2）不同预处理温度对稻秸预处理效果影响不显著,尿素预处理效果主要受尿素质量分数的影响。研究结果为秸秆的预处理工艺提供参考,并为秸秆厌氧干发酵技术提供数据支持。
Approximately, crop residues of 700 million tons are generated in China annually, accounting for 52.85% of the amount of biomass resources. Rice straw is one of the major agricultural residues and the output is about 203 million tons. Straw is a valuable renewable resource, but most of straw is burned in the field, which not only results in severe environmental pollution but also affects soil structure and cropland quality. The utilization of straw for anaerobic fermentation can simultaneously solve the waste of resources and environmental pollution problems. Anaerobic fermentation includes wet and dry anaerobic fermentation. Compared with wet anaerobic fermentation, dry anaerobic fermentation has many advantages such as water conservation, easy management, low energy consumption, high gas production rate. Rice straw mainly consists of 3 types of materials, i.e. polymer, cellulose, hemicellulose and lignin which are strongly intermeshed and chemically bonded by non-covalent forces and covalent cross linkages. Rice straw is normally difficult for dry anaerobic fermentation in its natural form due to the complex structure. Therefore, biomass pretreatment prior to anaerobic digestion has become a hot research topic which can reduce structural and compositional impediments of lignocellulosic biomass and expose the polymer chains of cellulose and hemicellulose to microbial breakdown for increasing the rate of biomass degradation and biogas yield. Recently, a variety of pretreatment methods have been researched and applied, such as crushing, milling, steam explosion, biological pretreatment, acid and alkaline pretreatments. Compared with other pretreatment methods, urea pretreatment process can be easily performed, and can alter the structure of lignocellulose, weaken the hydrogen bonding, partially dissolve hemicellulose and lignin, increase the nitrogen content and hence decrease the carbon-nitrogen ratio（C/N） of rice straw to the level of 20-30, which is more favorable for anaerobic digestion. Thus, different concentration of urea（2%, 4%, 6%, 8% and 10%） and different pretreatment temperature（25, 30, 35, 40, 45, 50℃） were investigated to evaluate the changes of lignocelluloses and the characteristics of dry anaerobic fermentation. The results showed that： 1） The different concentration of urea had a significant effect on the pretreatment of rice straw, which can break down lignocellulose structure of the straw and reduce the C/N ratio. The cumulative biogas production of the pretreated rice straw was 20.67%-38.20% higher than that of the untreated rice straw, and the optimal urea concentration for anaerobic fermentation was 4%. 2） The different pretreatment temperature had little effect on dry anaerobic fermentation of rice straw. Therefore, urea pretreatment of rice straw was mainly affected by urea concentration. The results provide a reference for pretreatment process, and also provide the data support for dry anaerobic fermentation technology of the straw.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第19期234-239,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
"果蔬加工废弃物转化生物天然气关键技术及装备"(2014BAD02B04)
"十二五"国家科技支撑计划项目子课题"炭基缓释肥成型工艺与装备"(2014BAD06B04)
关键词
秸秆
尿素
沼气
厌氧干发酵
预处理
木质素
纤维素
半纤维素
straw
urea
biogas
dry anaerobic fermentation
pretreatment
ligin
cellulose
hemicellulose
