共查询到18条相似文献,搜索用时 109 毫秒
1.
2.
3.
将小龙潭煤和先锋煤两种褐煤按不同比例混合进行热重分析研究.分析单一煤种及不同配比混煤的燃烧特性的差异,提出了反映煤燃烧着火及燃尽的燃烧特性综合判断指数.并根据化学动力学方法计算了各过程的化学动力学参数活化能和频率因子. 相似文献
4.
5.
以玉米秸秆和煤粉为原料,在不同原料配比,不同升温速率下,利用热重分析仪在模拟锅炉气氛下进行燃烧实验,采用Flynn-Wall-Ozawa法建立动力学模型,研究模拟锅炉气氛下玉米秸秆及其混煤燃烧的燃烧特性及其动力学,对比相同实验条件空气气氛下的燃烧工况结果表明,燃料的综合燃烧特性指数SN随升温速率的增大而成倍增长,因掺入煤粉的比例加倍而减半;随着掺混煤比例的增大,失重速率(DTG)曲线上固定碳燃烧阶段逐渐分化为2个失重峰,模拟锅炉气氛下分化现象更为明显;煤粉的掺入会使燃烧过程所需表观活化能波动增大。 相似文献
6.
7.
8.
9.
几种生物质的TG-DTG分析及其燃烧动力学特性研究 总被引:13,自引:1,他引:12
采用热重分析技术对木屑、麦秆、玉米秆和玉米芯4种生物质的燃烧特性进行了研究,考察了其着火、燃尽特性和综合燃烧特性,研究了升温速率对生物质燃烧特性的影响,同时在热天平上对其进行了动力学试验研究.研究表明:生物质燃烧过程大致可以分为3个阶段,即水分析出阶段、挥发分析出燃烧阶段、固定碳燃烧与燃尽阶段:生物质具有着火温度低、燃尽温度低、燃尽率高等优点;随着升温速率的提高,着火温度、各试样挥发分最大释放速率、燃尽温度均呈升高趋势,燃烧特性随升温速率的提高而变好.采用一级反应动力学模型和积分法对生物质燃烧动力学参数的研究表明,生物质具有较低的活化能,有利于点燃. 相似文献
10.
11.
12.
灰煤混合燃料的燃烧动力学特性研究 总被引:1,自引:0,他引:1
利用TGA/SDTA851e型热重分析仪,对煤及不同灰煤比的混合燃料进行了热失重实验,获得了其热失重特性曲线。采用单个扫描速率的Coats-Redfern法、多重扫描速率的FWO(Flynn-Wall-Ozawa)法和Starink法三种典型的热分析方法求取了各样品的动力学参数。结果表明:随着灰煤比的升高,样品燃烧反应平均过程的活化能增高;灰煤比由0升高到0.15时,样品的活化能、着火温度和燃烬温度变化较大;灰煤比从0.15升高到0.45时,活化能、着火温度和燃烬温度变化较小。同时,通过对比几种分析方法的计算结果,认为采用多重升温速率法求取活化能时要谨慎,建议采用单重升温速率法和多重升温速率法相结合来分析燃料的热解及燃烧机理。 相似文献
13.
Low NOx combustion of blended coals is widely used in coal-fired boilers in China to control NOx emission; thus, it is necessary to understand the formation mechanism of NOx and H2S during the combustion of blended coals. This paper focused on the investigation of reductive gases in the formation of NOx and H2S in the reductive zone of blended coals during combustion. Experiments with Zhundong (ZD) and Commercial (GE) coal and their blends with different mixing ratios were conducted in a drop tube furnace at 1200°C–1400°C with an excessive air ratio of 0.6–1.2. The coal conversion and formation characteristics of CO, H2S, and NOx in the fuel-rich zone were carefully studied under different experimental conditions for different blend ratios. Blending ZD into GE was found to increase not only the coal conversion but also the concentrations of CO and H2S as NO reduction accelerated. Both the CO and H2S concentrations inblended coal combustion increase with an increase in the combustion temperature and a decrease in the excessive air ratio. Based on accumulated experimental data, one interesting finding was that NO and H2S from blended coal combustion were almost directly dependent on the CO concentration, and the CO concentration of the blended coal combustion depended on the single char gasification conversion.Thus, CO, NOx, and H2S formation characteristics from blended coal combustion can be well predicted by single char gasification kinetics. 相似文献
14.
随着燃煤价格的攀升,燃料成本在火力发电厂运行成本中所占比重也逐步上升。在保证机组正常运行的前提下,研究、推广配煤掺烧,是节约能源、降低成本的有效措施之一。以600 MW机组为研究对象进行配煤掺烧实验,并对实验数据进行分析。为今后配煤掺烧的研究提供理论及数据参考。 相似文献
15.
混煤煤质及燃烧特性研究 总被引:1,自引:0,他引:1
针对混煤的煤质特性和燃烧特性开展实验研究,以指导燃煤电站科学合理的燃用混煤。研究结果表明,混煤的元素分析、工业分析及发热量满足质量加权平均,但混煤的可磨性和灰熔融特性不满足加权平均,低灰熔点煤中掺烧高灰熔点煤能显著提高混煤灰熔点,改善锅炉燃烧过程中的结渣问题,混煤灰熔点变化受到单煤灰成分的影响。热重实验分析表明,混煤的剧烈燃烧阶段与单煤存在明显差异,混煤的燃烧特性介于参与掺混的单煤之间,但不满足线性叠加,其燃烧过程存在着不同程度的交互作用。混煤的着火特性接近于易燃煤,而燃尽特性与难燃煤相近。除此以外,随着氧浓度的降低,混煤的燃烧特性明显变差,易燃煤对氧浓度的变化更加敏感。 相似文献
16.
17.
H. Singh S. Mishra D. K. Sharma 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2013,35(12):1151-1158
Abstract Kinetics of the combustion of original and depolymerized Assam, Raniganj and Talcher coals and Neyveli lignite has been studied under non-isothermal conditions in a thermogravimetric analysis apparatus by employing Coats and Redfern kinetic modeling. Depolymerization of coals through acidic phenoation was found to improve the reactivity of the coals for combustion. Similarly, depolymerization reaction also led to the improvement in the pyrolysis behavior of coals. The order and activation energy of the reactions have been reported. The kinetics studies of the residual coal obtained after the successive solvent extraction of coal has also been studied. The present studies on the reaction engineering of coal conversion and utilization technologies may help in the reactor design and in the process development engineering. 相似文献