选取2家典型生物质电厂除尘器处的飞灰,通过热重-傅里叶红外光谱联用（TG-FTIR）、X射线荧光光谱（XRF）、能谱（EDS）和X射线衍射（XRD）等分析手段,对飞灰的成分及其在高温下的失重特性进行研究。研究发现,生物质飞灰的高温失重机理较为复杂,在空气中加热时,碱金属氯盐的蒸发从380 ℃开始缓慢进行,600 ℃以下主要进行未燃碳的燃尽与碳酸镁的分解;600~750 ℃主要进行碳酸钙的分解;750 ℃后蒸发速度迅速上升,直至950 ℃完全蒸发;950 ℃以上发生矿物质的玻璃化反应和碱金属硫酸盐的蒸发。鉴于目前电力行业和ATSM对生物质飞灰含碳量的测试结果均不准确,该根据生物质飞灰的烧失机理,提出更加精确的氮气和空气气氛下600 ℃烧失量之差含碳量测试方法。
Abstract
In this study, the fly ashes are selected from two typical biomass power plant dust collectors,the composition of fly ashes and their loss on ignition characteristics at high temperatures have been studied through the combined experiments of TG-FTIR, XRF, EDS, XRD and other analytical methods. The study shows that weight loss mechanism of biomass fly ash at high temperature is more complicated,and the following chemical processes will occur when the fly ash are heated in air: unburned carbon is burned out and the MgCO3 is decomposed below 600 ℃ and the decomposition of CaCO3 occurs at 600 ℃-750 ℃. The evaporation of alkali chloride starts slowly at 380 ℃,and the evaporation speed increases rapidly higher than 750 ℃ and completely evaporation of alkali chloride happens until 950 ℃. The vitrification reaction of minerals and the evaporation of alkali sulfates occurs above 950 ℃. According to the study on weight loss characteristics,the research reveals that the results of carbon contents in biomass fly ash tested by current DL and ATSM standard are not accurate. Based on loss on ignition mechanism of biomass fly ash,this paper proposes a more accurate test method for carbon content analysis, that is the difference value of the ignition losses reacted at 600 ℃ under air and nitrogen.
关键词
生物质能 /
直接燃烧发电 /
飞灰 /
成分 /
烧失
Key words
biomass energy /
direct combustion power generation /
fly ash /
composition /
loss on ignition
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