热解温度对不同种类易腐垃圾生物质炭理化特性的影响

Effects of Pyrolysis Temperature on Physicochemical Properties of Different Kinds of Perishable Waste Biochar

随着垃圾分类政策的推行,易腐垃圾减量化、无害化、资源化处理越来越重要,热解炭化是一条具有环境效益和经济效益的处理途径.本研究利用扫描电镜、X射线衍射、傅里叶红外光谱及比表面积分析等表征方法,系统地分析了热解温度对6种易腐垃圾生物质炭(甘蔗皮炭、豌豆荚炭、橘子皮炭、柚子皮炭、桂圆皮炭和厨余垃圾炭)理化特性的影响.结果表明:①热解温度是影响生物质炭理化特性的关键因子,随热解温度的升高,易腐垃圾炭产率降低,灰分含量、pH和EC值增大,表面-OH、C-H、C=O、C=C和C-O-C等官能团含量减少,CaC_(2)O_(4)和K_(2)C_(2)O_(4)等草酸盐逐步分解为CaCO_(3)和K_(2)CO_(3).当热解温度为650℃时,厨余垃圾炭的产率、灰分含量、pH分别为41.7%、57.4%、9.8.②生物质原料种类是影响生物质炭理化特性的另一关键因子,不同种类的生物质炭表面元素含量、比表面积和形貌结构等参数均不相同,厨余垃圾炭的产率、灰分含量、表面钠元素和钙元素含量明显高于其他易腐垃圾炭.③易腐垃圾热解炭化主要包括脱水、脱羧、聚合、芳构化等过程,采用热解炭化技术处理易腐垃圾的毛利润约为630元/t,既具有环境效益又具有经济效益.上述研究结果为拓宽易腐垃圾炭资源化利用途径提供了基础数据,可有效助力无废城市建设.

With the implementation of waste classification policy,the reduction,innocuity and reuse of perishable waste is becoming more and more important.Pyrolysis and carbonization is an environmentally friendly and economical way for perishable waste treatment.The effects of pyrolysis temperature on the physicochemical properties of different kinds of perishable waste biochar(sugarcane peel biochar,pea pod biochar,orange peel biochar,grapefruit peel biochar,longan shell biochar and kitchen waste biochar)were systematically studied by scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy and BET method.The results show that:(1)The pyrolysis temperature is a key factor affecting the physicochemical properties of biochar.With the increase of pyrolysis temperature,the yield of perishable waste biochar decreases,the ash content,pH and EC value increase,and the contents of surface functional groups such as OH,C-H,C=O,C=C and C-O-C decrease.Oxalates such as CaC_(2)O_(4)and K_(2)C_(2)O_(4)gradually decompose into CaCO_(3)and K_(2)CO_(3)as the pyrolysis temperature increases.When the pyrolysis temperature was 650℃,the yield,ash content,pH and EC value of kitchen waste biochar are 41.7%,57.4%and 9.8,respectively.(2)The type of biomass raw material is another key factor affecting the physicochemical properties of biochar.Different types of perishable waste biochar have different surface element content,specific surface area,morphology and other parameters.The yield,ash content,surface sodium and calcium content of kitchen waste biochar are significantly higher than those of other perishable waste biochar.(3)The pyrolysis and carbonization process of perishable waste mainly includes dehydration,decarboxylation,polymerization and aromatization.The gross profit of pyrolysis and carbonization of perishable waste is about 630 RMB/t.Pyrolysis and carbonization technology has both environmental and economic benefits.The above results provide basic data for broadening the way of resource utilization of perishable waste biochar,and can effectively help the construction of waste-free cities.