半焦加压燃烧特性研究

【作者】 谷小兵；

【导师】 陈晓平； 段钰锋；

【作者基本信息】 东南大学 ， 热能工程， 2003， 硕士

【摘要】 第二代PFBC-CC技术是在第一代PFBC-CC技术的基础上发展起来的一项重要的洁净煤转化技术。第二代PFBC-CC系统中气化炉产生的半焦在PFB炉内燃烧效率的高低直接影响到整个系统的发电效率。本文运用自行研制的加压热重分析仪对半焦的燃烧进行了较为系统的研究。本文对原有的加压热重分析仪加以改进，改双炉膛结构为单炉膛双吊篮结构；改进了分析天平的结构；改造了原有的数据采集与信号处理系统。经改造后的加压热重分析仪的测量精度、准确性和可重复性都有很大幅度的提高。研究了加压条件下半焦的着火规律和燃烧稳定性。讨论了着火温度的确定方法，对加压下影响半焦着火特性的各种因素，如半焦种类、总压、氧浓度、粒径、加热速率等进行了试验研究。以纯碳的测试参数为基准，提出了燃烧稳定性的判别指数Rw。对加压条件下半焦的燃烧特性进行了研究。讨论了不同压力、不同氧浓度、不同粒径的半焦TG-DTG曲线图，并对它们加以比较。分析了半焦种类、实验总压、氧浓度、试样粒径和加热速率对最大失重速率、最大失重峰温、燃烧时间、燃烬温度等的影响。描述了不同实验条件下半焦燃烧反应性随温度的动态变化趋势，用平均质量反应性指数对半焦反应性加以评价。用积分法确定半焦燃烧反应级数，用分段线性回归法求取不同实验条件下的反应活化能和频率因子，并根据求得的动力学参数确定半焦燃烧的反应速度方程，以此来预测半焦的燃烧过程。更多还原

【Abstract】 The second generation PFBC-CC, which was developed on base of the first generation, is a significant clean-coal conversion technology. Semi-coke is production of gasifier, its combustion efficiency directly influenced power generation efficiency of the total system. This paper carried out a general research on combustion behavior of semi-coke with the aid of pressurized thermogravimetry, which is developed by ourselves.This paper ameliorated the old thermogravimetry, redesigned the structure of analytical balance , improved data acquisition and digital signal process system. Moreover, we replaced the double-hearths structure with one-hearth double-crucibles structure. All the experimental datum proved that the reconstructive system have better measurement precision, veracity and repeatability than the old one.This paper researched rules of ignition and combustion stability under pressurized environment, discussed how to calculate ignition temperature, and also studied the effects of many factors, such as categories of semi-coke, total pressure, oxygen concentration, particle size, heating rate, on ignition character. On base of pure carbon combustion test data, combustion stability parameter R. was proposed to evaluated combustion stability .Combustion character of semi-coke was studied under pressurized circumstance. The TG-DTG curves of combustion process, which were gained under different pressure, oxygen concentration and particle size, were analyzed in detail. This paper also studied effects of categories of semi-coke, total pressure, oxygen concentration, particle size and heating rate on maximum mass loss-rate, burning time, burn-out temperature, and described the dynamic transformation of combustion reactivity of semi-coke under different testing condition. Mean mass reactivity parameter was proposed to evaluate combustion reactivity of semi-coke.Integral method and linear regress in section method were adopted to calculate reaction progression and activity energy respectively. According to kinetic parameters calculated above, an equation of combustion rate was established to forecast combustion process of semi-coke.更多还原