【作者】 陈峰；

【导师】 胡勇有； 周少奇； 宋乾武；

【作者基本信息】 华南理工大学 ， 能源与环保， 2019， 博士

【摘要】 中国生活垃圾具有“高含水、高有机质、高混合度、低热值”的复杂特性,其中含水率是制约其无害化、减量化、资源化的关键因素。降低生活垃圾含水率的常用技术有机械干化、热干化、生物干化等,但在投资、能耗、运行成本、运行稳定性和干化效率,及对周围环境友好性方面都有提升空间。其中,高温好氧生物干化技术是利用高温好氧微生物菌群在降解垃圾中有机质时所释放的热量,在干化仓内形成持续稳定的高温环境,将垃圾中的液态水蒸发为气态水,进入干化仓的低温低湿空气变成了高温高湿的气体后经由通风系统排出,进而快速去除垃圾中绝大部分水分的工艺。目前,国内外采用的多是好氧堆肥发酵等好氧生物干化技术,存在干化温度低(35～45℃)、速度慢、周期长、干化效果不佳、产品热值仍然较低而难以资源化应用等诸多问题。提高生物干化温度是解决这一系列问题的突破点,为此开展高温生物干化技术的工程化研究,构建适应中国国情的高温好氧生物干化技术体系,对推动我国生活垃圾处理走向“以废物变资源、废物变能源”的可持续发展方式具有指导意义。本文开展了多类型的高温好氧生物干化工艺性能试验,通过对包括干化过程和效果影响因素、干化产品应用适宜性、以及干化烟气污染控制等的系统研究,确定了高温好氧生物干化工艺的工程运行条件;在此基础上,应用环境生物学、生化反应动力学、热力学等原理,通过建立高温好氧生物干化技术的数学模型和过程控制方法,开展了高温好氧生物干化技术的机理和优化控制策略研究。在构建高温好氧生物干化技术体系的基础上,进一步提出了高温烟气、太阳能等余热辅助、小型一体化、烟气除尘脱硫脱硝等系列高温好氧生物干化技术方案,并通过工程案例分析,对该工艺进行了系统的技术经济评价。通过上述试验研究得到结论如下:(1)高温好氧生物干化是一种适合中国生活垃圾特点的干化方法,温度范围为50℃～70℃。(2)高温好氧生物干化过程中,垃圾的含水率由约58.9%逐步降低到约18.6%,减量化50%以上,垃圾低位热值由约9000kJ/kg提高至18000kJ/kg。(3)影响高温好氧生物干化的主要因素是有机质含量>微生物菌种>通风风量>仓体构造>氧气浓度>颗粒粒径>仓体保温性能,其中高温好氧微生物菌种、通风风量、仓体构造是决定性的外部影响因素。(4)高温好氧生物干化过程排放气体中NO、SO等浓度低于《大气污染物综合排放标准》(GB 16297—1996)排放标准限值;高温好氧生物干化过程不产生渗滤液,对周围环境的影响较小,不需要配套专门的废气和废水处理设施。(5)生活垃圾高温好氧干化后可制成垃圾衍生燃料(RDF),RDF在掺烧过程中锅炉燃烧稳定、燃烧排放污染物浓度低,高温好氧生物干化产物可以作为一种清洁高效的新型能源,RDF/原煤的掺烧质量比宜控制在5%～10%。(6)高温好氧生物干化过程中垃圾堆体的温度变化规律与微生物的生长规律相吻合,证实了高温好氧生物干化的产热机理是遵循微生物分解合成规律的,干化过程中的热量来自于微生物分解垃圾中有机质所释放的热能。(7)高温好氧生物干化技术可将生物干化周期缩短至7d;干化过程可划分为温升期、高温期及温降期,各期历时为0.6d、5.6d、0.8d;水分去除主要在高温期;(8)高温好氧生物干化各阶段的控制策略:在干化初期以满足供氧量、快速升温为主要控制依据,干化中期以氧气供给保证微生物释放最大的热量与通风除湿吸收热量之间所建立的动态平衡为控制依据,干化末期以满足通风除湿为主并使仓内垃圾堆体温度快速降低。(9)该技术可用于现有垃圾焚烧和综合处理厂的改造项目,改造部分的工程投资约3万元/t、处理成本约23元/t、新增经济效益约66元/t。(10)采用本高温好氧生物干化技术,我国生活垃圾可以采用“收集～好氧生物干化～压缩～转运”的收运模式和“粗破碎+高温好氧生物干化+RDF燃料制造+燃料焚烧(或综合利用)”的处理处置模式,从根本上提高我国生活垃圾处理效率。我国政府对环保产业的鼓励和扶持政策提供了巨大的垃圾处理供给市场,高温好氧生物干化技术顺应了这种市场需求变化,是一种解决中国生活垃圾“三高一低”难题的高效、经济、实用的垃圾生物预处理方法,未来会有广阔的应用市场。更多还原

【Abstract】 Chinese domestic waste has the complex characteristics of "high water content,high organic matter,high mixing degree and low calorific value",in which the water content is the key factor to restrict its harmless,reducing and recycling.The common technologies for reducing the water content of domestic waste are mechanical drying,heat drying,biological drying,etc.,but there is still room for improvement in investment,energy consumption,operating cost,operational stability and drying efficiency,and environmental friendliness.Among them,the high temperature aerobic biological drying technology is to use the garbage released heat from the process of organic matter degradation of high temperature aerobic microbial flora,forming a continuous stable high-temperature environmentin the dry silo,making the waste liquid water evaporate into gaseous water,and then the ventilation system change the dry silo of low-temperature and humid air into high temperature and humidity gas and then discharge the gas.(In the dry silo,the low-temperature and humid air is changed into high temperature and humidity gas,and then the gas is discharged from ventilation system)The process to quickly remove most of the water from the waste.Currentlyaerobic composting and other common aerobic bio-drying technologies,that have been widely applied in China and other countries,have many problems such as low drying temperature(35～45°C),low speed,long cycle,poor drying effect,low product calorific value,hard to recycle..To improve the biological drying temperature is the breakthrough point to solve this series of problems.Therefore,to carry out the engineering research of high temperature biological drying technology,to build a high temperature aerobic biological drying technology system to adapt to the national conditions,It has guiding significance for the sustainable development of domestic waste treatment in China to "waste resources,waste to energy".In this paper,the researcher performed many types of high temperature aerobic biological drying process performance tests,through systematical researches about drying process and factors that influence its effect,drying product’s application suitability as well as drying flue gas pollution control,to determine the engineering operating conditions of high temperature aerobic drying process.On this basis,we performed the establishment of high temperature aerobic biological drying technology mathematical model and Process control methodand the high temperature aerobic biological drying technology mechanism and optimization control strategy research by the application of environmental biology,biochemical reaction kinetics,thermodynamics and other principles.On the basis of constructing high temperature aerobic biological drying technology system,this paper further puts forward a series of high temperature aerobic biological drying technology scheme,such as high temperature flue gas,solar energy and other waste heat auxiliary,small integration,flue gas dedusting desulfurization and denitrification.Through the engineering case analysis,this paper also performs the technical and economic evaluation of the process.The results are as follows:(1)High temperature aerobic biological drying is a kind of drying method suitable for Chinese domestic waste,and the temperature range is 50℃～70℃.(2)During high temperature aerobic biological drying process,the water content of garbage is gradually decreased from about 58.9% to about 18.6%,which is more than 50%,and the low calorific value of garbage is decreased from about 9000kj/kg to 18000kj/kg.(3)The main factors that affect the drying of high temperature aerobic are organic matter content,microbial strain,ventilation volume,warehouse structure,oxygen concentration,particle size,and the thermal insulation property of the silo,wwherein the high temperature aerobic microorganism strain,ventilation volume and silo structure are the decisive external factors.(4)the concentration of NO and SO in the discharge gas of the high temperature aerobic biological drying process is lower than the emission standard limit of the air pollutant Comprehensive emission standard(GB 16297-1996);High temperature aerobic biological drying process does not produce leachate,and the impact on the surrounding environment is small,which do not need to support special wastegas and wastewater treatment facilities.(5)After high temperature aerobic biological drying process,treated domestic waste can be made into refuse derived fuel(RDF).RDF’s combustion process is stable,and its combustion pollutant emission concentration is low.The products of high temperature aerobic biological drying can be used as a clean and efficient new energy source.The RDF/coal blending mass ratio should be controlled within 5～10%.(6)During the high temperature aerobic biological drying process,the variation of temperature of waste is consistent with the growth of microorganism,which proves that the energy used for biological drying is from the high temperature aerobic microorganism’s decomposition of organic matter in the waste.()(7)High temperature aerobic biological drying technology can shorten the biological drying cycle to 7d;the drying process can be divided into temperature rise period,high temperature period and temperature drop period.The durations of each period are 0.6d,5.6d,0.8d;water removal is mainly at high temperature.(8)The control strategies at various stages of high temperature aerobic biological drying: At the early stage,meeting the oxygen supply and heating up rapidly are the main control basis.At the middle stage,setting the oxygen supply to establish a dynamic balance between the maximum heat release of microorganism and ventilation and dehumidification absorption of heat is the main control basis.At the later stage,meeting the need for ventilation and dehumidification and rapidly reducing the temperature of waste are the main control basis.(9)The technology can be used in the existing waste incineration and comprehensive treatment plant renovation project.The transformation of some of the project investment is about 30,000 yuan/t,processing costs is about 23 yuan/t,the new economic benefits of about 66 yuan/t.(10)Using this high temperature aerobic biological drying technology,China’s domestic waste can use the "collection ～ Aerobic biological Drying ～ compression ～ transshipment" of the shipping mode and "coarse crushing + high temperature aerobic biological dry +RDF fuel Manufacturing + fuel incineration(or comprehensive utilization)" treatment and disposal model,fundamentally improve the efficiency of domestic waste disposal in China.Chinese government’s supporting and encouraging policies to the environmental protection industry provide a huge supply market for waste treatment.High temperature aerobic biological drying technology adapts to this change of market demand.It is a efficient,economical,practical waste biological pretreatment method and a solution to the “three high and one low” problem of Chinese domestic waste.There will be a broad application market for this technology.更多还原