Feasibility and pilot study of coupled anaerobic digester and pyrolyzer for co-processing organic waste to renewable natural gas and biochar

厌氧消化（AD）技术可以生产碳中和的可再生天然气（RNG），显著降低能源系统的碳化程度，减少温室气体排放。其他好处包括减少动物废物储存和土地传播对当地大气的污染，最大限度地提高生物质废物的价值，并从美国生产有机肥料，以降低RNG生产的总成本。在不列颠哥伦比亚省有一些小规模的设施，用于厌氧消化农业废物和城市来源分离的有机物以生产沼气。然而，为了广泛地部署AD系统以大规模大量生产RNG以满足政府的RNG混合目标，仍需要克服若干挑战以提高AD系统在处理各种有机废物原料、减少碳足迹和更好地管理废物固态流中的效率。AD-热解一体化系统是一种提高AD反应器稳定性和产气率的新方法，其总能量转化率由单一AD反应器的33-50%提高到AD-热解一体化系统的80%以上。迄今为止，大多数研究都是在实验室或小型试验单位中进行的，没有整合。通过对AD反应器和微波流化床热解反应器的环境和技术经济分析，以及小型AD反应器和微波流化床热解反应器的试验研究，系统评价了好氧消化-微波热解一体化系统的可行性。重点研究了AD反应器在添加热解水溶液（APL）和生物炭的情况下共消化农作物残留物、庭院垃圾、食物垃圾和动物垃圾的性能、微波催化热解固体微生物质制备生物炭以及优化生物炭作为AD反应器的添加剂以改善AD性能和用于其他应用。该项目的总体目标是为利益相关者提供AD+热解技术，以满足不列颠哥伦比亚省和加拿大的可再生天然气混合需求和温室气体减排目标。

Anaerobic digestion (AD) technologies can produce carbon-neutral renewable natural gas (RNG) thatsignificantly decarbonizes the energy system and reduces GHG emissions. Additional benefits include reducinglocal atmosphere pollution from animal waste storage and land spreading, maximizing the value of biomasswaste and producing organic fertilizers from digestate to reduce the overall cost of RNG production. There aresome small-scale facilities in British Columbia for anaerobic digestion of agricultural waste and urbansource-separated organics for biogas production. However, to deploy AD system broadly for the production ofRNG in large quantity at large scale to meet the government's RNG blending target, several challenges stillneed to be overcome to improve the AD system efficiency in treating various organic waste feedstock, reducecarbon footprint, and better manage the waste digestate streams. Integrated AD-pyrolysis system was arelatively new approach to increase the stability of AD reactor and biogas production, and it has shown a greatpromise in increasing the overall energy conversion from 33-50% of single AD reactor to more than 80% in thecombined AD-pyrolysis system. Majority of studies to date have been performed in components in laboratoryor small pilot units without integration. We propose to systematically evaluate the feasibility of an integratedanaerobic digestion and microwave pyrolysis system based on environmental and techno-economic analysesand the test of a small pilot AD reactor and a microwave-assisted fluidized bed pyrolysis reactor. The focus ison the AD reactor performance for co-digestion of crop residues, yard waste, food waste and animal waste withthe addition of pyrolysis aqueous liquid (APL) and biochar, microwave catalytic pyrolysis of solids digestatefor biochar production and the optimization of biochar properties as an additive to the AD reactor to improveAD performance and for other applications. The overall objective of this project is to provide stakeholders anAD+pyrolysis technology to meet the renewable natural gas blending demands and greenhouse gas emissionsreduction targets in British Columbia and Canada.