为满足新型超超临界对冲旋流燃烧锅炉首次大修后启动要求,同时针对锅炉最上层燃烧器烧损问题,开展了基于锅炉运行安全的冷态优化试验研究,主要包括一次风调平、磨煤机冷态通风阻力测试,以及炉内贴壁风、燃烧器冷却风、内外二次风冷态优化和燃烧器飘带试验.试验结果表明:该类对冲旋流燃烧锅炉仅通过调节较少一次粉管可调缩孔,就能满足一次风风速调平要求;锅炉CF层左右侧贴壁风挡板具有良好的调节特性,但在不同挡板开度下水冷壁贴壁风风速整体偏小;CF燃烧器冷却风随着风门挡板开度增大,风速增长缓慢;F6燃烧器飘带试验显示飘带易卷吸至燃烧器喷口.建议锅炉运行中增加各层贴壁风、燃烧器冷却风及外二次风挡板开度,以预防水冷壁高温腐蚀、冷却风量不足及外二次风旋流强度过大等问题,提高锅炉设备运行安全性.

某电厂2号机组在启机过程中,A引风机发生异响并失去调节作用,机组被迫停机.通过运行和维护等方面进行排查分析,发现由动叶卡涩引起的漂移是导致引风机失速、出现异响的主要原因.就该故障暴露出的问题提出了预防性措施,为同类型风机的运行及维护提供一定的参考.

针对某电厂两台燃煤机组煤耗数据偏差较大问题,对两台机组发电、供电煤耗进行对比评估.通过查验机组运行参数、入炉煤煤质数据、灰渣可燃物、掺配方案、机组指标统计表等数据,基于能耗指标数据,采用耗差法对煤耗影响因素进行分析,同时采用正平衡修正法对供电煤耗数据进行分析和修正计算,最后得出相关结论.

针对某燃气-蒸汽联合循环发电机组余热锅炉低压蒸发器泄漏事故,分析管内壁表面的形态和管道材质物理性质,检测管道厚度,分析泄漏事故的原因,并给出有针对性的建议.

通过对某330 MW锅炉排烟温度DCS值偏差大、排烟温度偏高原因进行分析,并对空气预热器检修效果进行了评估.对于排烟温度偏差问题,主要从温度标定、燃烧偏差及空气预热器换热效果等方面进行分析.结果表明:DCS排烟温度平均数据能较好反映空气预热器出口截面温度数据,炉右侧排烟温度DCS值偏差大的原因为炉右侧烟道靠右DCS值与实测值存在较大负偏差;330 MW负荷下空气预热器检修后与检修前相比,空气预热器烟气侧换热效率降低约0.5％,排除空气预热器漏风率变化对排烟温度的影响,检修后比检修前空气预热器出口烟气平均温度(修正后)升高约3.0 ℃.建议从空气预热器更换的换热元件材质、间隙或安装工艺等方面查找原因,以解决空气预热器检修无效的问题.

在10 MW级生物质气化耦合燃煤发电工程项目上,考察了当量比、添加蒸汽、掺混秸秆对稻壳气化特性的影响.在当前的实验条件下,随着当量比在0.14 ～0.20的范围内增加时,CO、H2和CH4的体积分数均随之减少,燃气热值和气化效率也随当量比的增大而降低;添加适量蒸汽可以促进CO、H2和CH4及燃气热值的提高,气化效率则随蒸汽量的增加而升高;当秸秆掺混比例逐渐增加时,CO、H2和CH4的体积分数和燃气热值出现了不同程度的下降,气化效率也不断降低.

为有效评价生物质气化耦合燃煤锅炉系统能量转换过程,分析该系统的节能潜力,以某10 MW循环流化床生物质气化炉耦合大型超临界燃煤机组为例,建立了该耦合系统的(火用)分析控制体模型,利用Aspen plus平台对该系统实际运行过程进行(火用)平衡分析.结果 表明:当前运行工况下,生物质气化过程(火用)损失是耦合系统最大的(火用)损失,达到42.28％,其次是可燃气体在燃煤锅炉内的燃烧及传热过程,为25.32％.因此系统运行过程中应采取优化运行措施,减小气化过程(火用)损失,同时气化炉应尽量与高参数的大型机组耦合运行,可燃气体选取在燃煤锅炉合适位置输入,以保证充分燃烧.

针对某电厂2×660 MW超超临界锅炉混煤掺烧下灰渣可燃物突升问题,分析了灰渣可燃物的变化规律,根据入炉煤煤质化验报告、掺配方案、运行历史数据及采取的技术措施,并结合现场实际状况,从燃用煤种及锅炉运行情况2个方面分析了灰渣可燃物突升的原因,并提出了相应的建议.分析表明:近期特定供应商煤种(上海煤)煤质波动较大,且存在极难燃的煤质成分,引起灰渣可燃物异常升高;炉渣可燃物最高时间段,锅炉额定负荷时锅炉运行氧量为0.96％,明显低于日常运行控制值和设计值,且高温烟气温度比其他同类工况下该区域烟气温度低约55℃～60℃,是导致锅炉燃烧进一步恶化的原因.燃用上海煤时,建议采用提高磨煤机加载力、掺烧投运方式选择中下层燃烧器、加大掺烧磨上下二次风开度等措施,以提升掺烧该煤种的燃尽程度.

Slagging is often happened during the combustion in the boiler of circulating fluidized bed (CFB). The causes of slagging after graphite coal mixed burning in the CFB boiler in a power plant were analyzed, and the preventive measures and suggestions were put forward.

Nitrogen emission during chemical looping combustion (CLC) of rice husk based on hematite in a batch fixed bed reactor was studied.Different variables affecting the process, such as reduction temperature and steam content, were tested.The results show that higher reduction temperature results in a hig her carbon conversion which reaches the highest value when the steam flow is 1.0 g/min.Furthermore, there are no NO2 detected at all experiments.The rise of reduction temperature from 750 to 900 ℃ could contribute to the rise of NO, whereas the concentration of N2 O reaches the highest value at 850 ℃.Both N2 O and NO increase remarkably with the increase of steam flow.Nevertheless, the increasing rate of NO is faster than that of N2 O. Besides, KAlSi3 O8 is detectable in the reduced oxygen carrier, attributing to the reaction of K in biomass with hematite.

The experiment was conducted using glutamic acid, glycine and phenylalanine as N-containing model compounds. During their reduction in chemical looping combustion (CLC), the effects of temperature and K element on NOx release were studied. The results indicated that release of volatile-N was quick during whole CLC process, and yields of NO and NO2 increased with increasing temperature, whereas N2O concentration showed fluctuation. Higher nitrogen content in model compounds, more difficult for conversion from nitrogen to NOx. K element showed no significant effect on NOx release of the three amino acids during CLC process except that NO emission from phenylalanine.

Chemical looping combustion (CLC) is one of the promising technologies to capture CO2 with low cost. Owing to the existence of nitrogen in fuel, the emission of fuel-NO is a significant concern during the CLC process. This work evaluated NO release in the CLC process of bituminous coal and petcoke using iron ore as an oxygen carrier in a fluidized bed. The effect of several factors was evaluated, including bed material, fuel type, temperature and gasification medium. The results indicate that in the fuel reactor (FR), fuel-NOx, due to the reaction between NH3/HCN and iron ore was supported only when the iron ore was reduced from Fe2O3 to Fe3O4. Compared with the case of an inert bed material, NO yield during the gasification in an iron ore bed material was relatively higher due to the enhanced char-gasification and the oxidization effect of iron ore. For the bituminous coal, NO release in FR was mainly due to the volatile release and subsequent oxidation by iron ore. For the petcoke process, NO release in FR could mainly be ascribed to the char-gasification and subsequent oxidization of NOR-precursors by iron ore. The elevated temperature and the use of H2O/N-2 in comparison to CO2 could efficiently enhance the fuel conversion and NO precursors release in FR. Thus, NO yield in FR increased, whereas that in AR correspondingly decreased. Furthermore, the NO release during continuous coal CLC was investigated in a 1 kWth CLC prototype based on the iron ore oxygen carrier. Overall, the elevated fuel reactor temperature and the use of H2O as gasification medium are beneficial to reduce NO release in the CLC system. (C) 2014 Elsevier B.V. All rights reserved.

Chemical looping combustion (CLC) is a promising technology to capture CO2. However, the low conversion efficiency of fuel is the key challenge for the in situ gasification CLC with natural iron ore as an oxygen carrier. The reactivity of the selected 696 K2CO3-modified iron ore (6KMIO) was first determined by H-2 and CO in TGA, and an enhanced reduction reactivity of 6KMIO was confirmed. Afterward, the feasibility of 6MKIO for coal CLC was tested in a 1 kW continuous reactor. The continuous reactor could be stably operated without any tendency of agglomeration or sintering among 6KMIO particles. Compared with use of the raw iron ore, the use of 6KMIO enhanced the coal conversion and the gasification-products conversion, promoting the CO2 capture efficiency. Furthermore, the mechanism of the catalyzed coal CLC process and the release of sulfur was explored.