Rice straw to Biogas (R2B)

稻草转化为沼气（R2B）

• 批准号: EP/P032826/1
• 负责人: Sonia Heaven
• 金额: $ 35.26万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP032826%2F1
• 关键词: Rice; straw; Biogas; R2B

The research at Southampton seeks to maximise biogas from rice straw through the use of innovative pre-treatment techniques, evaluation of nutritional requirements of the anaerobic consortium, and optimisation of the bioreactor in terms of its configuration and physical environment. The work will build on the rich but fragmented knowledge which represents the state of the art in rice straw digestion. This suggests that mechanical pre-treatment may be effective, although reliable quantitative data are not available. Batch methane potential tests will be carried out to assess the reaction kinetics of the straw after the application of mechanical treatments. The flail mill is targeted as a preferred technology because of its simple and robust construction, lack of reliance on cutting blades that are rapidly blunted in rice straw applications, and history of successful use in developing countries e.g. in the tea industry. Its performance will be compared with that of other systems such as hammer and ball mills. The batch tests will be followed by more extensive trials using semi-continuous fed digesters to establish specific and volumetric gas productivities and digester operational stability. Compositional analysis of the straw will indicate not only of its theoretical methane potential but also its nutritional value and buffering capacity, as a basis for selective additions of essential elements to improve digester performance. The semi-continuous trials will be conducted at both mesophilic and thermophilic temperatures over a range of loading conditions, with monitoring of key operating parameters to establish baseline kinetic data against which pilot plant performance can be compared and optimised. Prior art also suggests that rice straw may be deficient in natural pH buffering and performance can be enhanced through co-digestion with animal slurries. To date, work has mainly focused on cattle and swine manures. The planned work will additionally consider duck and poultry manure, as these are readily available in the Philippines and other parts of the world where rice is extensively cultivated. Both shredding and manure addition will significantly alter the rheology of the substrate, which will impact on the operating mode of a dry digestion system. Permeability tests will therefore be conducted at various stages through the batch dry digestion process. This will involve running small-scale 'dry' digesters that simulate the pilot plant and provide data for direct comparison and assessment of factors of scale. The propensity for acidification will also be assessed, and the potential requirement for second-stage methane recovery from the leachate will be considered: if necessary this could be achieved by coupling to a low-tech second stage reactor (e.g. anaerobic filter) with recycling of acid-stripped liquid to overcome buffering issues. Other control measures, such as batch sequencing of the dry digesters and optimisation of the substrate-to-inoculum ratio at start-up, will also be evaluated as part of an operational strategy to match harvesting schedules and minimise storage requirements. Where permeability is an issue the use of inert bulking material will be tested to improve hydraulic distribution and reduce short circuiting. Previous work has shown that agricultural residues with a high solids content require long operating periods to reach the pseudo steady state conditions needed to determine the nutritional needs of the anaerobic consortia and the digestate properties. This provides the opportunity to monitor changes in biomass characteristics and population structure using advanced microscopy, Raman spectroscopy and gene techniques. Of key importance is the overall sustainability of the rice straw energy production system, and the laboratory and pilot plant data will feed into previously developed energy balance models to provide processed data output for the work of the Manchester team.

南安普敦的研究旨在通过使用创新的预处理技术，评估厌氧财团的营养需求以及以其构型和物理环境来优化生物反应器，从而最大程度地利用稻草沼气。这项工作将建立在丰富但分散的知识的基础上，该知识代表了稻草消化中的最新水平。这表明机械预处理可能是有效的，尽管没有可靠的定量数据。将进行批处理甲烷电位测试，以评估使用机械处理后稻草的反应动力学。 Flail Mill是一种首选技术，因为其简单且坚固的结构，缺乏依赖米稻草应用中迅速钝化的切割刀片的依赖，以及在发展中国家成功使用的历史，例如在茶业。它的性能将与其他系统（例如锤子和球厂）进行比较。批处理测试将进行更广泛的试验，使用半连续的喂养消化体来建立特定和容量的天然气生产率和消化器的操作稳定性。对稻草的组成分析不仅表明其理论甲烷电位，而且还表明其营养价值和缓冲能力，这是选择性添加基本要素以改善消化层性能的基础。半连续试验将在各种负载条件下在中间和嗜热温度下进行，并监测关键工作参数以建立基线动力学数据，可以对其进行比较和优化的试验植物的性能。先前的艺术还表明，稻草可能缺乏自然pH缓冲，并且可以通过与动物泥浆共同消化来增强性能。迄今为止，工作主要集中在牛和猪粪上。计划的工作还将考虑鸭子和家禽粪便，因为这些工作在菲律宾和世界其他地区很容易获得，那里有大米的种植。切碎和肥料添加都会显着改变底物的流变学，这将影响干燥消化系统的操作模式。因此，将通过批处理干燥消化过程在各个阶段进行渗透性测试。这将涉及运行小规模的“干”消化器，这些消化剂模拟试点工厂并提供数据以直接比较和评估规模因素。还将评估酸化的倾向，并且将考虑从渗滤液中回收二阶段甲烷的潜在需求：如有必要，可以通过将酸剥离的液体与低网络第二阶段反应器（例如厌氧过滤器）耦合来实现这一目标来实现。其他控制措施，例如对启动时干摘要的批处理测序以及对基质造型比的优化，也将作为匹配收获时间表并最大程度地减少存储要求的运营策略的一部分进行评估。如果渗透性是一个问题，则将测试使用惰性体积材料以改善液压分布并减少短路。先前的工作表明，具有较高固体含量的农业残基需要长时间的工作时间才能达到确定厌氧财团和消化特性的营养需求所需的伪稳态条件。这为使用高级显微镜，拉曼光谱和基因技术监测生物量特征和种群结构的变化提供了机会。关键的重要性是稻草能源生产系统的总体可持续性，实验室和试点工厂的数据将融入先前开发的能源平衡模型，以为曼彻斯特团队的工作提供处理的数据输出。