600MW超临界机组掺烧印尼褐煤、越南无烟煤试验研究

Experimental Study of Mixed Combustion of Indonesia-originated Lignite and Vietnam-originated Anthracite in a 600 MW Supercritical Unit

在设计煤种为优质烟煤、对冲燃烧方式的600MW超临界锅炉上,进行了用神华、塔山等4种烟煤和印尼褐煤掺烧越南无烟煤的试验。通过燃烧调整手段可保证40%比例越南煤稳定燃烧,神华、印尼煤结焦性明显改善,但飞灰可燃物含量升高,飞灰粒径变粗。试验结果表明:无烟煤燃尽比着火稳燃更难解决,解决此问题并兼顾设备安全的有效手段为:煤粉细度应尽可能靠近无烟煤燃烧的要求,而一次风温、风量应按易燃煤种的要求控制。此外,煤粉浓度、旋流强度、集中给氧、易燃煤种的活性及锅炉负荷等都对混煤的燃烧有较大影响。

An experiment was performed of burning four kinds of bituminous coal,including Shenhua-and-Tashan-originated coal,and Indonesia-originated lignite,in a mixed combustion of Vietnam-originated anthracite on a 600 MW supercritical boiler with its design coal rank being high quality bituminous coal under an opposed-firing mode.Through combustion adjustment,it can guarantee a proportion of 40% Vietnam-originated coal to burn steadily,the coking characteristics of Shenhua and Indonesia-originated coal can be significantly improved.However,the flying ash combustible content increases and the flying ash particle diameter becomes bigger.The test results show that the burn-out of anthracite is more difficult to attain than its ignition and steady combustion.The effective means to solve this problem and give due consideration to the safety of equipment items can be given as follows:the fineness of pulverized coal should be close to the requirement for anthracite combustion to the maximum possible degree while the primary air temperature and its feed rate should be controlled as required for easily-ignited coal ranks.In addition,the concentration of pulverized coal,swirling intensity,centralized oxygen supply,activity of the easily-ignited coal rank and boiler load etc.all exercise a relatively big influence on the combustion of the coal mixture.