【作者】 刘洪鹏；

【导师】 李惟毅； 陈冠益； 王擎；

【作者基本信息】 天津大学 ， 热能工程， 2012， 博士

【摘要】 油页岩作为常规油气的重要补充资源，在全球资源战略中的地位日益彰显。油页岩干馏过程中产生大量的残渣，既浪费了能源资源，又对环境造成极大威胁，已成为油页岩开发利用中的瓶颈问题。本文提出以高热值生物质与干馏残渣混烧的方法，通过理论与实验研究，深入探讨了油页岩干馏残渣与生物质的混烧特性。详细分析了油页岩干馏残渣与生物质基础燃料特性。基于热重分析方法，对油页岩干馏残渣与生物质的混合燃烧特性进行了大量实验研究，深入探讨了燃料种类、混合比及升温速率等因素对混合物燃烧特性的影响。研究结果表明，随着生物质掺混比例增加，干馏残渣与生物质混合燃料的着火温度及燃尽温度降低，燃烧速率增加，从而改善了干馏残渣的燃烧特性。随着升温速率的增加，TG曲线向高温侧移动，燃尽温度升高；DTG曲线上的失水峰、挥发分释放燃烧峰以及固定碳燃烧峰逐渐变宽，并且各峰峰值随升温速率的增加而变大。理论上，基于单扫描率法Coats-Redfern方程、等转化率法KAS方程与DAEM模型，详细研究了油页岩干馏残渣与生物质混烧过程中的动力学特性。研究结果表明，运用等转化率两种方法获得的动力学特性相近，而单扫描率法求解结果与等转化率法相比在数值上存在一定的差别，但所呈现出的规律性是一致的。详细研究了油页岩干馏残渣与生物质混烧过程中的协同作用，揭示了混合比、升温速率、生物质种类等因素对混烧特性的相互影响规律。基于Avrami转化动力学理论，对样品燃烧的热失重过程进行了模拟。模拟结果与采用动力学方法获得的活化自由能表征的规律相一致，为进一步探索油页岩干馏残渣与生物质多组分燃烧特性提供了理论基础。在混烧机理研究的基础上，完成了油页岩干馏残渣与玉米秸秆颗粒的循环流化床混烧实验。系统研究了燃料配比、一次风率等因素对炉膛温度、底渣、返料、飞灰可燃物含量及燃烧效率的影响。结果表明，在油页岩干馏残渣中掺入一定比例玉米秸秆颗粒完全可以稳定、高效地燃烧。基于欧拉双流体封闭模型，对一台已投运的65t/h燃油页岩高低差速循环流化床锅炉进行了数值模拟并用实际运行数据进行验证。设计开发了一台130t/h燃用桦甸油页岩干馏残渣与玉米秸秆颗粒的高低差速循环流化床锅炉，运用所建立模型对该锅炉流动特性进行了模拟预测。更多还原

【Abstract】 As the important supplementary energy of conventional oil and gas resources, oilshale shows more and more important status in the global resource strategy. However,a huge quantity of retorting solid waste will be formed in thermal processing of oilshale in vertical retorts. The retorting solid waste will gradually become thebottleneck in the development and utilization of oil shale. At the same time, it is notonly a waste of energy and resources, but also poses a great threat to the environment.As the low grade fuel with high ash content, low calorific value and low volatile, ithas been shown that circulating fluidized bed combustion of retorting solid wastecould be a promising technology. In this thesis, the co-combustion way of retortingsolid waste with high calorific value biomass has been proposed, and theco-combustion characteristics and interactions between oil shale retorting solid wasteand biomass have been deeply studied in the theory and experiment aspects.A detailed analysis of the basic fuel properties of the oil shale retorting solidwaste and biomass has been made. A large number of experimental studies onco-combustion characteristics of retorting solid waste and biomass have beenconducted and the effect of fuel type, mixing ratio and heating rate on co-combustioncharacteristics have been systematically discussed. The TG-DTG results show that,with the increase of biomass mixing proportion, the ignition temperature and burnouttemperature are reduced, and the burning rate are increased, and the combustioncharacteristics get improved. With the increase of the heating rate, the combustion TGcurves shift to the high temperature range, and the ignition temperature, burnouttemperature and the temperature corresponding to the maximum burning rate areincreased. Meanwhile, the dehydration peak, volatile release peak and the fixedcarbon burning peak all get broaden, and all the peak values are increased.In theory, based on the single scan rate method (Coats-Redfern equation),iso-conversional method (KAS equation and DAEM model), the co-combustionkinetic characteristics of retorting solid waste and biomass have been studied in detail.The results show that the dynamic characteristic obtained from iso-conversionalmethod is relatively close, while the difference exists compared with the method ofsingle scan rate method, but the regularity is consistent.The synergy of co-combustion process between the oil shale retorting solid waste and biomass has been investigated in detail and the interaction effect of the mixingratio, heating rate, types of biomass and other factors on the co-combustioncharacteristics has been revealed. Based on the Avrami transformation kinetic theory,the TG combustion process is simulated. The simulation results of free energy ofactivation are consistent with that obtained by KAS equation. This provides atheoretical basis for further exploration of co-combustion characteristics ofmulti-component of oil shale retorting solid waste and biomass.On the basis of the co-combustion mechanism, the combustion experiment of oilshale retorting solid waste with cornstalk particles is finished on circulation fluidizedbed test pilot. A comprehensive and systematic research of fuel proportion, a primaryair ratio on combustion temperature, slag, recycle, combustible content in fly ash andcombustion efficiency. The results show that, in the oil shale retorting solid wastemixed with a certain proportion of cornstalk particles, it can be completely stable andefficient combustion.Based on Euler closed two-fluid model, the numerical simulation for a65t/h oilshale-fired high-low bed CFB boiler that has been put into operation has beenperformed and verified with the actual operating data. A new130t/h oil shale retortingsolid waste-fired and cornstalk particles-fired high-low bed CFB boiler has beendeveloped. The flow characteristics of the boiler have been simulated and predicted.更多还原