Oxy–fuel (O2/CO2) combustion technology shows great potential for carbon reduction. However, difference in the combustion atmosphere would affect coal combustion characteristics and pollutant emissions. In order to explore oxy–fuel combustion characteristics, two typical Chinese coals, sub–bituminous and lean coal, were utilized. Based on thermogravimetry and pilot–scale test, the ignition and burnout characteristics under oxy–fuel and air combustion atmosphere were investigated. Besides, the NOx emission characteristics were also investigated on the pilot–scale test. Through experimental results, these two kinds of coal showed different combustion characteristics, mainly due to differences in coal quality. Compared with air combustion, oxy–fuel combustion affected the coal combustion process. Firstly, the ignition temperature of sub–bituminous and lean coal decreased from 418 and 477 °C to 405 and 415 °C, respectively; the burnout temperature also decreased from 855 and 985 °C to 808 and 838 °C, respectively. Then, coal combustion performance was evaluated by comprehensive combustion characteristics (S); with an increase in S from, respectively, 3.659 and 2.013 to 4.826 and 3.545 × 10−8(min−2 × K−3), the combustion performance significantly improved. Then, the char burnout time was advanced for 1~3 min. Similar results were obtained on the pilot–scale test. The ignition temperatures decreased from 505 and 552 to 490 and 512 °C, respectively. Moreover, the char burnout rate increased by 0.5~5% and 2~11%, respectively. Lastly, the NOx concentration in flue gas was 2.2~2.6 and 2.0~2.3 times higher for the two kinds of coal under oxy–fuel combustion.

油泥及油泥渣可燃成分较低,灰分较高,水分较大,其中可燃油份易挥发,油泥热解过程中25℃～180℃阶段下降比较高,主要为水分蒸发,还含有少量低沸点的汽油馏分,180℃～350℃下降5％左右,该部分主要为轻柴油馏分.350℃～500℃为高沸点有机物的挥发.＞500℃时,失重量主要部分为残存油渣热解挥发,约占2％.油泥渣的热解曲线与风干油泥热解曲线基本一致.可以大体分为四个阶段,＜200℃时的水分蒸发和低沸点烷烃的释放阶段,200℃～500℃的高沸点油质组分的热解挥发阶段,主要以石蜡为主.500℃～650℃为重油质(油渣)分解释放阶段,其中轻油质热解阶段为整个热解的主要部分,失重量约为16％,重油质部分含量较少约为3％.

本文利用电加热炉对高铁煤与高岭土掺混进行燃烧特性实验研究，发现随着掺混比例升高，混煤的燃尽率明显降低，NO x 排放浓度呈现先降低后增加趋势，煤质的灰渣越来越容易吹扫。综合不同高岭土掺混比例下煤质的燃尽特性、NO x 排放特性以及结渣特性，建议高岭土掺混比例控制在10%左右，可以保证煤质具有较好燃尽特性和NO x 排放特性的同时，有效地缓解高铁煤严重结渣的问题。

本文利用热重分析仪对废菌棒的燃烧特性进行了相关研究,分析了废菌棒的热解过程、升温速率对热解过程的影响、挥发分热力特性和氮释放特性,得出了废菌棒热解表观活化能,并研究了典型煤种掺混废菌棒后的着火特性.

以半焦掺混原煤为试验对象,在添加少量的氧化钙时,其灰熔点变化比较明显,呈下降趋势,随着氧化钙添加比例的增加,灰分的熔点降低程度呈现平缓,当氧化钙的比例进一步增加时,熔点不再下降,反而呈现略有上升的现象,由于氧化钙与灰中的其他组分反应生成低熔点化合物,当氧化钙含量进一步增加时,此时会呈现氧化钙过剩,由于其本身为高熔点物质,进而导致样品的熔点略有提高;还原性气氛能够明显降低半焦混煤灰的熔点,因此局部缺氧,会导致炉膛内结渣严重化;大粒径化学组成均匀性比小粒径的灰分差,在高温下,各组分不能充分接触反应,会形成一些灰熔点较低的共熔物,从而降低灰分熔点.

Drop Tube Furnace experiments were carried out to investigate the fast pyrolysis characteristics of three typical coals. The process of fast pyrolysis was simulated by a one-step pyrolysis model as well as a Chemical Percolation Devolatilization (CPD) model. The results indicate that coal rank, reaction temperature and residence time have complex influences on volatile release and nitrogen conversion. Both activation energy and frequency factor, which decrease with increasing coal rank, show obvious differences for the three considered coals. The volatile release coefficient QR is relative to coal rank and heating rate which fluctuates from 1.02 to 1.72. Predictions of volatile release and coal nitrogen conversion obtained from CPD model agree well with experiments. In addition, the one-step pyrolysis model could predict the volatile release of low-rank coal, whose precision is related to coal rank.

为了研究W火焰锅炉内空气动力场特性,通过调整三次风的不同分配比例(三次风量占总二次风量的比例),利用冷态试验模拟试验与数值模拟来对比分析其流动规律.分析得出前后墙气流下冲强度存在偏差,始终呈现前强后弱的趋势,并且偏差随着三次风分配比例的增大逐渐减小.沿炉膛高度方向随三次风分配比例的增大,下行风的强度逐渐降低,冷灰斗上回流区域逐渐增大且向上流速逐渐增大.沿炉膛深度方向,下行气流折算速度在前后墙附近呈现先增加后减小的变化趋势,在炉膛中部速度基本保持不变.