以麦秸与鸡粪为原料,采用批次式中温厌氧发酵方式,探究微量元素Fe2+、Co2+、Ni2+对混合厌氧发酵的影响.实验结果表明:Fe2+、Co2+、Ni2+最佳浓度分别为210、32、32 mg/L,当Fe2+、Co2+、Ni2+的添加浓度在适宜范围内时,可显著(p<0.05)提高发酵系统产CH4潜力及CODs去除率;当Fe2+浓度为210 mg/L、Co2+浓度为32 mg/L、Ni2+浓度为32 mg/L时,其CH4累积产量分别为322.21、331.19、357.10 mL/(g VS),相比于对照组为245.35 mL/(g VS)显著(p<0.05)提高31.33％、34.99％、45.54％,CODs去除率依次为61.83％、57.01％、63.63％,提高CH4产量的排序为Ni2+>Co2+>Fe2+,Ni2+对CH4累积产量的提高最明显,同时也有最高的CODs去除率,且各实验组pH值均稳定在适宜范围内,厌氧发酵稳定运行,可为麦秸与家禽粪便的沼气工程提供技术参考.

[目的]降低预处理成本、提高秸秆预处理后的酶解效果,模拟自然界低温环境并结合氨水对高粱秸秆进行预处理.[方法]通过单因素试验分别探究氨水低温冻融预处理中浸泡液的液固质量比、冷冻温度、冷冻时长、氨水质量分数对高粱秸秆酶解的影响,采用正交试验对预处理条件进行优化,对预处理前后高粱秸秆的成分采用范式法测定,物理化学结构用红外光谱和X射线衍射分析.[结果]单因素试验中,浸泡液的液固质量比、冷冻温度、冷冻时长和氨水质量分数在不同水平下均显著提高了高粱秸秆酶解还原糖的产量(P<0.05).正交试验最优预处理条件为浸泡液的液固质量比12,冷冻时长12 h,冷冻温度?10℃,氨水质量分数8％.相较于未进行预处理的秸秆,氨水低温冻融处理的秸秆半纤维素含量下降42.42％;木质素含量下降50.76％;秸秆的还原糖产量为302.87 mg·g?1,较未预处理组提高了80.34％;纤维素结晶度提高了57.02％.[结论]氨水低温冻融预处理能有效破坏高粱秸秆木质纤维素间原有的连接结构,溶解半纤维素,木质素的单体和聚合结构被破坏,提高了高粱秸秆的酶解还原糖得率以及纤维素结晶度.

y This work aims to enhance and optimize the methane production by anaerobic co-digestion of soybean straw (SS) and farm wastewater. Thermo oxidation and alkali pretreatments were applied during the present study. The effects of chemical composition were investigated and the influence of thermochemical pretreatment on methane production by SS with wastewater was evaluated by Batch and semi-continuous experiments. All pretreatments were found significant (P < 0.05) to enhance the lignocellulosic degradability and methane yield. The highest methane yield which was recorded by 2% wet NaOH presoaking prior at 4.5% H2O2, 100 degrees C for 30 min pretreatment was 206 ml/g.VS which was 62% higher than the untreated straw during batch experiments. The synergistic effects were demonstrated during the anaerobic co-digestion of soybean straw and farm wastewater and the digestion period was shortened to almost half. In addition, a range of organic loading rate (OLR), (1.5-7.5) g.VS.L-1.d(-1) was applied for the semi-continuous experiments and OLR of (3-6) g.VS.L-1.d(-1) was concluded as the optimum OLR with the highest methane production capability of 194 ml/(g.VS.L.d). (C) 2019 Published by Elsevier Ltd.

为了解决犁旋一体机作业过程中调节机具问题,设计了一种犁旋一体机自动调平系统,该系统包括执行机构、控制系统、液压系统.根据犁旋一体机自身的特点,提出了一种确定调平角度范围的方法,并根据实际田间作业情况,运用EDEM仿真软件进行田间作业的虚拟仿真,仿真结果表明:地表平整度小于2 cm,满足农艺要求.在设计和仿真的基础上,进行田间试验,将手动调平的犁旋一体机的作业情况和自动调平的犁旋一体机的作业情况进行对照,分析了作业过程中机具的角度变化和作业后的耕深及其稳定性,地表平整度.结果表明:自动调平犁旋一体机相对于手动调平犁旋一体机,在耕深的稳定性和耕后地表平整度上有较为明显的提高,前者耕深稳定系数达到87.31％,后者为84.76％.前者地表平整度为1.97 cm,后者为2.56 cm.