摘要
生物质是一种可再生能源,将其作为固体燃料甲烷化,可以减少对煤炭等化石燃料的依赖,也成为能源消费结构调整中天然气生成的重要途径。生物质固废甲烷化主要有三种途径:生物化学转化途径(厌氧消化)、热化学转化途径甲烷化以及结合化学链气化技术的化学链甲烷化。厌氧消化工艺使用微生物细菌将生物质固废转为小分子生物,过程中可产生沼气,沼气主要由50%~70%的甲烷和30%~50%的二氧化碳组成,目前从单段消化池发展到多段多批次消化系统。重点介绍了7种工艺流程,包括Waasa工艺、Dranco工艺、Valorga工艺、Kompogas工艺、顺序分批厌氧堆肥(SEBAC)工艺、厌氧相态固体(APS)消化工艺及久保田一体式厌氧膜生物反应器(KSAMBR)工艺,其中KSAMBR是近十年来发展起来的一种新型工艺,其浸没式膜可保留产甲烷菌,过滤可溶解的甲烷发酵抑制剂,工艺过程稳定、蒸煮器的容积小。气化结合甲烷化工艺将气化炉和甲烷化反应器前后连接,结合去除硫化物、氯化物、焦油和固体灰等净化过程,最终获得合成天然气。介绍了荷兰能源技术中心(ECN)生物质制天然气工艺、德国太阳能氢气研究中心(ZSW)工艺、瑞士保罗谢勒研究所(PSI)工艺等3种工艺流程。其中,ECN生物质制天然气工艺800kW的中试规模装置,处理量约160kg/h;ZSW工艺多管式反应器采用镍基催化剂,通过熔盐多管热交换手段保持反应器整体温度在500℃左右,可获得含量为81.9%的甲烷气体;PSI工艺采用快速内循环流化床,气化反应温度为850℃,出口气体中CH_(4)含量以干气体计约为9%。化学链甲烷化工艺将CaO吸附CO_(2)的过程加入到气化过程中,免去后续去除CO_(2)工艺,提高了H/C比,从而简化甲烷化的后处理过程。基于CaO循环的化学链甲烷化不仅可以吸收甲烷化反应中的热量,同时对生产过程的CO_(2)进行封存,将实现碳的负平衡。该技术有望在资源化利用生物质固废方面实现大规模应用。研究成果为生物质固废甲烷化技术的工艺选择和设计提供参考。
Biomass,which can be used as solid fuel for methanation to not only reduce the dependence on fossil fuels such as coal but also become an important way to generate natural gas for energy consumption restructuring,is a kind of renewable energy.The three main branches of biomass solid waste methanation are biochemical conversion pathway(anaerobic digestion),thermochemical conversion pathway methanation,and Chemical Looping Methanation(CLM)combined with Chemical Looping Gasification(CLG)technology.The anaerobic digestion process uses microbial bacteria to convert biomass solid waste into small molecule organisms,and can produce biogas.Biogas is mainly composed of 50%~70%methane and 30%~50%carbon dioxide.It is currently evolving from a single-stage digester to a multi-stage,multi-batch digestion system.The seven types of technological processes are mainly introduced,including Waasa,Dranco,Valorga,Kompogas,Sequential Batch Anaerobic Composting(SEBAC),Anaerobic-phased Solid(APS)digestion and Kubota Submerged Anaerobic Membrane Bioreactor(KSAMBR)are introduced in detail.KSAMBR is a novel process developed in recent ten years.Its submerged membrane can not only retain methanogens but also filter soluble inhibitors of the methane fermentation.The process is stable and the volume of the digester is small.The gasification combined with methanation process connects the gasifier and methanation reactor,and combines the purification process to remove sulfide,chloride,tar and solid ash to obtain synthetic natural gas.The biomass to natural gas process developed by Energy Research Centre of the Netherlands(ECN),the Centre for Solar Energy and Hydrogen Research Baden-Württemberg(ZSW)process and the Paul Scherrer Institute(PSI)process are discussed in detail.An 800 kW pilot scale unit using ECN biomass to natural gas process has a processing capacity of about 160 kg/h.The multi tube reactor in ZSW process adopts nickel based catalyst.The overall temperature of the reactor is maintained at about 500℃by molten salt multi tube heat exchange,and the methane with a content of 81.9%can be obtained.The PSI process adopts a fast internal circulating fluidized bed.The gasification reaction temperature is 850℃and the CH_(4) content in the outlet gas is about 9%when measured as dry gas.The CLM process adds CaO to absorb CO_(2)during the gasification process.This can eliminate the need for subsequent CO_(2)removal and increase the H/C ratio,thus simplifying the post-treatment process of methanation.The CLM based on CaO cycle can not only absorb the heat in methanation reaction,but also store the CO_(2)during the production process,which will realize the negative balance of carbon.This technology is expected to realize large-scale application in the resource utilization of biomass solid waste.The research results provide a reference for the process selection and design of biomass solid waste methanation technology.
作者
陈德露
安风霞
邵旦洋
王晓佳
CHEN Delu;AN Fengxia;SHAO Danyang;WANG Xiaojia(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,China;China Energy Science and Technology Research Insititute Co.,Ltd,Nanjing 210023,China)
出处
《电力科技与环保》
2022年第3期184-194,共11页
Electric Power Technology and Environmental Protection
基金
国家重点研发计划(2019YFC1906802)。
关键词
生物质
厌氧消化
气化
甲烷化
化学链
biomass
anaerobic digestion
gasification
methanation
chemical looping
