dynamic aeration

  • 文章类型: Journal Article
    本研究旨在设计一种具有动态曝气功能的集成好氧-厌氧反应器,该反应器可根据实时氧气浓度自动调节,并研究高固体负荷玉米秸秆的好氧预处理和随后的干共厌氧消化(co-AD)特性。生理化学特性,和甲烷生产。来自好氧预处理阶段的高温原料快速进入AD阶段,无需运输,有效地提高了co-AD的启动和甲烷产量。氧气浓度范围,曝气速率,预处理时间影响累积曝气时间,温升,在好氧预处理过程中相互作用地去除有机物,和低曝气率是相对优选的。虽然木质纤维素的去除量随着预处理时间的增加而增加,木质素的最大消除效率仅为1.30%。从好氧预处理到co-AD的过渡阶段的接种物注射和co-AD期间的渗滤液回流对于除了好氧预处理之外稳定地生产甲烷也至关重要。冷空气减弱了好氧预处理的温升,低温渗滤液降低了co-AD过程中的甲烷产量。氧气浓度范围为13%-17%,曝气量为0.10m3/(min·m3),预处理时间84小时,接种量40%,渗滤液每天回流三次,和双层接种是最佳的,以提高集成好氧-厌氧消化系统的抗低温能力和实现高甲烷产量。玉米秸秆和猪粪的最大累积和挥发性固体(VS)甲烷产量分别达到444.58L和266.30L/kgVS。
    This research aimed to design an integrated aerobic-anaerobic reactor with dynamic aeration that was automatically regulated based on real-time oxygen concentration and investigate the aerobic pretreatment and subsequent dry co-anaerobic digestion (co-AD) characteristics of highly solids-loaded corn stover and swine manure in terms of temperature rise, physiochemical characteristics, and methane production. The high-temperature feedstocks from the aerobic pretreatment phase rapidly entered the AD phase without transportation and effectively improved the start-up and methane production of the co-AD. Oxygen concentration range, aeration rate, and pretreatment time affected the cumulative aeration time, temperature rise, and organic matter removal interactively during aerobic pretreatment, and a low aeration rate was relatively preferable. Although the lignocellulose removal increased with the increase in pretreatment duration, the maximal lignin elimination efficiency only reached 1.30%. The inoculum injection in the transition phase from aerobic pretreatment to co-AD and the leachate reflux during co-AD were also critical for producing methane steadily apart from aerobic pretreatment. The cold air weakened the temperature rise of aerobic pretreatment, and the low-temperature leachate reduced the methane production in the co-AD process. An oxygen concentration range of 13%-17%, aeration rate of 0.10 m3/(min·m3), pretreatment time of 84 h, inoculum loading of 40%, leachate refluxing thrice per day, and double-layer inoculation were optimum for improving the integrated aerobic-anaerobic digestion system\'s ability to resist low temperatures and achieving high methane production. The maximal cumulative and volatile solids (VS) methane yields of corn stover and swine manure reached 444.58 L and 266.30 L/kg VS.
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  • 文章类型: Journal Article
    常规曝气方式为强制连续通风或等间隔曝气,在堆肥过程中,均匀的曝气速率不会发生变化。基于微生物在不同堆肥阶段的不同耗氧量的动态按需曝气方法可以解决氧气供应不足或过度曝气的问题。本研究旨在设计一种动态曝气的好氧堆肥系统,研究了动态曝气对玉米秸秆和猪粪好氧堆肥过程中温升和理化特性的影响,优化氧气浓度的控制参数。在动态曝气下实现了更高的温度和更长的高温持续时间,从而加速有机化合物的分解。动态曝气有效降低了曝气频率,对流潜热和水分损失,以及堆肥中后期的耗电量。根据排气中氧气浓度14%-17%调节的动态曝气是最佳的。在最优条件下,50℃以上的时间持续了8.5天,最高温度,有机物去除,种子萌发指数达到65.82℃,37.59%,74.59%,分别。与传统的间歇曝气相比,电耗降低了33.58%。动态曝气将是提高好氧堆肥特性,减少能耗和热废气排放的一种有竞争力的方法。尤其是在冷却成熟期,这对于实现规模化堆肥的低成本生产和促进有机肥料产业的蓬勃发展具有重要意义。
    The conventional aeration method is compulsorily continuous ventilation or aeration at equal intervals, and a uniform aeration rate does not vary during composting. A dynamic on-demand aeration approach based on the diverse oxygen consumption of microorganisms at different composting stages could solve the problems of insufficient oxygen supply or excessive aeration. This study aims to design an aerobic composting system with dynamic aeration, investigate the effects of dynamic aeration on the temperature rise and physicochemical characteristics during the aerobic composting of corn straw and pig manure, and optimise the control parameters of oxygen concentration. Higher temperatures and longer high-temperature durations were achieved under dynamic aeration, thereby accelerating the decomposition of organic compounds. Dynamic aeration effectively reduced the aeration frequency, the convective latent heat and moisture losses, and the power consumption in the middle and later stages of composting. The dynamic aeration regulated according to the oxygen concentration of 14%-17% in the exhaust was optimum. Under the optimal conditions, the period above 50 ℃ lasted 8.5 days, and the highest temperature, organic matter removal, and seed germination index reached 65.82 ℃, 37.59%, and 74.59%, respectively. The power consumption was decreased by 33.58% compared to the traditional intermittent aeration. Dynamic aeration would be a competitive approach for improving aerobic composting characteristics and reducing the power consumption and the hot exhaust gas emissions, especially in the cooling maturation stage, which was of great significance for realising the low-cost production of composting at scale and promoting the blossom of the organic fertiliser industry.
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  • 文章类型: Journal Article
    TetranychusurticaeKoch(Acari:Tetranychidae),有两个斑点的蜘蛛螨,是一种限制墨西哥草莓产量的害虫。关于荨麻疹与健康的草莓植物或被同种蜘蛛螨感染的草莓植物之间发生的相互作用知之甚少。因此,在这项研究中,我们评估了由挥发性有机化合物(VOC)介导的T.urticae对健康草莓植物的吸引力,以及由草食动物诱导的植物挥发物(HIPV)介导的特异性损伤的植物。首先,我们使用Y管嗅觉仪对通过动态曝气获得的植物和提取物进行了双重选择测试。使用气相色谱-质谱(GC-MS)鉴定提取物的挥发性组成。一旦化合物被鉴定出来,我们还对选定的合成化合物进行了双重选择测试。与对照(清洁空气)相比,荨麻疹对健康和受损植物都表现出更大的吸引力。然而,当同时提供健康和受损的植物时,没有观察到显著的偏好.通过动态曝气获得的提取物的生物测定产生了类似的结果。鉴定的化合物是萜烯和芳烃。我们发现健康植物排放的VOCs与螨受损植物的HIPV之间存在定性和定量变化。单个化合物α-pine烯(10ng),假本烯(10纳克),和柠檬烯(1ng)和10ng的由α-pine烯假本烯均三甲苯柠檬烯(5:34:57:4)制成的混合物比对照吸引了更多的T.urticae。然而,假本烯柠檬烯(91:9)的二元混合物比评估的其他二元或三种化合物的混合物更具吸引力。这些结果可能有助于制定该害虫的管理策略。
    Tetranychus urticae Koch (Acari: Tetranychidae), the two-spotted spider mite, is a pest that limits strawberry production in Mexico. Little is known about the interactions that occur between T. urticae and healthy strawberry plants or strawberry plants infested by conspecific spider mites. Therefore, in this study we evaluated the attraction of T. urticae to healthy strawberry plants mediated by volatile organic compounds (VOCs), and to plants damaged by conspecifics mediated by herbivore-induce plant volatiles (HIPVs). First, we conducted dual-choice tests using a Y-tube olfactometer with plants and extracts obtained through dynamic aeration. The volatile composition of the extracts was identified using gas chromatography-mass spectrometry (GC-MS). Once the compounds were identified, we also conducted dual-choice tests with selected synthetic compounds. Tetranychus urticae exhibited greater attraction to both healthy and damaged plants compared to the control (clean air). However, when healthy and damaged plants were offered simultaneously, there was no significant preference observed. Bioassays with extracts obtained by dynamic aeration yielded similar results. The identified compounds were terpenes and aromatic hydrocarbons. We found qualitative and quantitative changes between the VOCs emitted by the healthy plant and the HIPVs from mite-damaged plants. The individual compounds α-pinene (10 ng), pseudocumene (10 ng), and limonene (1 ng) and 10 ng of the blend made of α-pinene + pseudocumene + mesitylene + limonene (5:34:57:4) attracted more T. urticae than the control. However, the binary blend of pseudocumene + limonene (91:9) was more attractive than the other binary or three-compound blends evaluated. These results may contribute to developing strategies for the management of this pest.
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