Heat transfer in the process of pyrolysis of garden waste
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摘要: 为了更加准确地控制实际生产中热解物各部分的温度、提高园林废弃物的处理效率及处理质量、更好地利用园林废弃物热解后得到的产物,对园林废弃物热解过程中的热量传递问题进行研究。从测量园林废弃物热解过程中的温度分布及变化入手,了解热解过程中的热量传递特征,并在此基础上通过热力学分析建立热解传热模型,利用ANSYS有限元软件对所建模型进行模拟求解。对比分析模拟结果与试验数据后,根据实际情况对模型相关参数进行优化,最终获得了具有一定应用价值的热解传热模型。在此过程中不仅得到热解过程中反应器内的温度分布,还得知热解温度、物料多少、物料所处位置等因素都对热解过程中的热量传递有明显影响;相同条件下,热解温度越高、热解物料越少,则热量传递越强;同一时间内,温度梯度较大的位置热量传递较强;根据热解过程中反应烧瓶瓶壁上的温度载荷、物料表面的对流换热载荷不是恒定的这一现象,建立了侧壁温度关于木粉高度以及木粉上方流体温度关于时间的函数关系式。Abstract: Temperature has a significant effect on pyrolysis and determines the components of pyrolysis products. The distribution of pyrolysate temperature, however, relies on the heat transfer characteristics during the pyrolysis process. To study the heat transfer characteristics during the pyrolysis process of garden waste, the temperature distribution and variation in garden waste were measured. The software ANSYS was taken to simulate the heat transfer process, and the heat transfer model was established by comparative analysis of the experimental data and the simulation value. The results indicated that the heat transfer ability increased along with ascending pyrolysis temperatures and decreased along with the increase of the amount of garden waste; the heat transfer ability was proportional to temperature gradient. Simultaneously, the relationship between the temperature on flask lateral wall and the height of garden waste powder, and the relationship between the temperature above garden waste powder and time were established based on the phenomenon that the temperature load on the reaction flask wall and the convective heat transfer load on the garden waste powder surface were not constant. This study, to a certain extent, will provide theoretical guidance to garden waste pyrolysis.
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Key words:
- garden waste /
- pyrolysis /
- heat transfer /
- temperature distribution
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[1] YU X, SUN X Y, XU J, et al. Surveys on present situation of garden waste and discussion of reuse strategies in Beijing[J]. Journal of Shandong Forestry Science and Technology,2009,39(4):5-7. [2] 于鑫,孙向阳,徐佳,等.北京市园林废弃物现状调查及再利用对策探讨[J].山东林业科技,2009,39(4):5-7. [3] LI Z. Mode of developing new energy sources: garden waste to produce ethanol technology[J]. Ecological Economy,2011(11):161-165. [4] 李智.浅谈新能源发展模式:园林废弃物生产乙醇技术[J].生态经济,2011(11):161-165. [5] 田赟.园林废弃物堆肥化处理及其产品的应用研究[D].北京:北京林业大学,2012. [6] TIAN Y. Green waste composting and the products as the peat substitutes in growth media[D]. Beijing:Beijing Forestry University,2012. [7] MI F, CUI Y Q, ZHANG Y J. Recycling mode of urban greening waste and other wooden waste[J]. Journal of Beijing Forestry University(Social Sciences),2013,12(2):58-62. [8] 米锋,崔逸秋,张玉静.城市绿化及木质废弃物循环利用模式分析[J].北京林业大学学报(社会科学版),2013,12(2):58-62. [9] SU X M. Research of resource utilization and sitting layout of Beijing landscaping residues[D].Beijing:Beijing Forestry University,2010. [10] 苏贤明.北京园林废弃物资源化利用与选址布局研究[D].北京:北京林业大学,2010. [11] REVEL R, SCOULDING K. Collecting, processing and financing yard trimmings programs[J]. Biocycle,1999,9:66-70. [12] SUN X Y,SUO L N,XU J,et al.The present situation and policy of the garden waste management disposal[J].Garden,2012(2):12-17. [13] YANG H. Discussion on resource utilization of garden waste[J]. Anhui Agricultural Science Bulletin,2010,16(15):181-182. [14] EUROPEAN UNION. EU Directive 99/31/EC on the landfill of waste[S]. Official Journal of the European Union,1999,182:1-19. [15] MU J, YU Z M,LI L,et al. Preparation and analysis of wood vinegar with wood residues[J]. Journal of Beijing Forestry University,2008,30(2):129-132. [16] LEROY B L, BOMMELE L, REHEUL D, et al. The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture: effects on soil fauna and yield[J]. European Journal of Soil Biology,2007,43(2):91-100. [17] 孙向阳,索琳娜,徐佳,等.园林绿化废弃物处理的现状及政策[J].园林,2012(2):12-17. [18] WANG H Y. Study on regulating mechanism of wood vinegar to plant growth[D]. Harbin:Northeast Forestry University,2005. [19] ANDERSEN J K, BOLDRIN A, SAMUELSSON J, et al. Quantification of greenhouse gas emissions from windrow compostingof garden waste[J]. Journal of Environmental Quality,2010,39(2):713-724. [20] JING L J.Heat transfer modeling and study in a single wood particle during the pyrolysis process[D]. Beijing:Beijing Forestry University,2011. [21] ZHENG S Q, CAO J. Numerical simulation of wood temperature field based on finite element theory[J].Forest Engineering,2007, 23(1):11-14. [22] 杨晖.园林废弃物的资源化利用探讨[J].安徽农学通报,2010,16(15):181-182. [23] 母军,于志明,李黎,等.木材剩余物的木酢液制备及其成分分析[J].北京林业大学学报,2008,30(2):129-132. [24] LAI Y H, MA C Y, SHI M H. Research on the heat and mass transfer in the pyrolysis process of the biomass fuel bed under radiant heating[J].ActaEnergiae Solaris Sinica,2006,27(7):661-665. [25] UEHARA T, HORIO Y, FURUNO T, et al. Effect of wood vinegars on germination and radicle growth ofseed plants [J]. Mukuzai Gakkaishi,1993,39:1415-1420. [26] HE Z B, ZHAO Z J, YI S L.The heat and mass transfer theory and numerical analysis in wood drying[M].Beijing:China Forestry Publishing House,2013:105-110. [27] YANG S M, TAO W Q. Heat transfer[M]. 4th Edition.Beijing:Higher Education Press,2006:44. [28] 王海英.木醋液对植物生长调节机理研究[D].哈尔滨:东北林业大学,2005. [29] CHENG W L. Study on the mathematical models of desiccation process and analysis methods of wood powder[J]. Demolition Equipments and Materials,2003,32(3):10-13. [30] 景亮晶.木材热解过程中单颗粒内部传热模型的建立与研究[D].北京:北京林业大学,2011. [31] 郑世强,曹军.基于有限元理论木材温度场的数值仿真[J].森林工程,2007,23(1):11-14. [32] 赖艳华,马春元,施明恒.辐射加热条件下生物质燃料层热解过程的传热传质[J].太阳能学报,2006,27(7):661-665. [33] 何正斌,赵紫剑,伊松林.木材干燥热质传递理论与数值分析[M].北京:中国林业出版社,2013:105-110. [34] 杨世铭,陶文铨.传热学[M].4版.北京:高等教育出版社,2006:44. [35] 陈万里.木粉干燥过程的数学模型及分析方法[J].爆破器材,2003,32(3):10-13. -
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