Electric Power Technology and Environmental Protection

【目的】新疆煤储量巨大，但由于其富含碱金属，在锅炉燃烧中易引发结渣和沾污问题，限制其大规模应用。本文旨在通 过混煤燃烧技术优化其燃烧特性并抑制结渣，为安全环保利用新疆煤炭资源提供技术支持。【方法】选取望布煤、新疆红沙泉高 碱煤、中高热值混煤、中低热值混煤及高硫煤为实验原料，对不同煤种进行了煤质与灰成分分析，随后通过一维火焰燃烧器和 黑体炉分别研究了不同配煤比例下新疆高碱煤的燃烧特性和熔融机制，利用双色法测温技术量化火焰温度；通过黑体炉高温 实验研究灰样熔融与结渣特性，分析灰渣形态及最低结渣温度。【结果】研究结果表明，掺混适量的新疆高碱煤能有效改善煤样 的燃烧特性。特别是在新疆高碱煤与其他煤种(如中高热值煤)混合时，能够提升火焰温度，从未掺混时火焰温度为688 ℃，提 高到掺混25%的新疆高碱煤后为809 ℃，并促进煤的充分燃烧。在结渣方面，随着新疆高碱煤掺混比例的提高，灰熔点降低， 更容易结焦。而新疆煤与中高热值混煤、高硫煤掺烧后的煤灰结渣温度由1 100 ℃上升到1 200 ℃，有效减少了结渣现象的发 生。因此，通过调整不同煤种的掺混比例，不仅能够提高火焰温度、优化燃烧特性，还能有效抑制结渣行为。【结论】混煤燃烧技 术通过优化配比，采用25%~50%新疆煤和中高热值煤可协同提升燃烧效率与抗结渣能力。而掺混中高热值混煤或高硫煤能 显著提高灰熔融温度，为新疆高碱煤的大规模清洁利用提供了关键技术依据。

 [Objective] Xinjiang coal has huge reserves, but due to its richness in alkali metals, it is prone to slagging and staining problems in boiler combustion, which limits its large-scale application. The aim of this study is to optimise the combustion characteristics and inhibit slagging through mixed coal combustion technology to provide theoretical support for the safe and environmentally friendly use of Xinjiang coal resources. [Methods] Wangbu coal, Xinjiang high red sand spring high alkali coal, medium-high calorific value mixed coal, medium-low calorific value mixed coal and high sulphur coal were selected as experimental raw materials, and the coal quality and ash composition of different coal types were analysed, and the combustion characteristics and melting mechanism of Xinjiang high alkali coal with different coal proportion were then studied by a one-dimensional flame burner and a black-body furnace, respectively, to quantify the flame temperature by using two-color pyrometry. The melting and slagging of ash samples was investigated by the high-temperature experiments of the black-body furnace. The melting and slagging behaviours of the ash samples were investigated, and the ash morphology and minimum slagging temperature were analyzed. [Results] The results show that the blending of appropriate amount of Xinjiang high alkali coal can effectively improve the combustion characteristics of coal samples. Particularly when Xinjiang high-alkali coal is blended with other coal types (such as medium-to-high calorific value coal), it can increase the flame temperature, rising from 688 °C without blending to 809 ° C with a 25% blend of Xinjiang high-alkali coal, thereby promoting more complete combustion of the coal. In terms of slagging, as the proportion of Xinjiang high-alkali coal increases, the ash melting point decreases, making slagging more likely. However, when Xinjiang coal is co-fired with medium-to-high calorific value blended coal or high-sulfur coal, the slagging temperature of the coal ash increases from 1,100 °C to 1,200 °C, effectively reducing slagging. Therefore, by adjusting the blending ratios of different coal types, it is possible not only to increase the flame temperature and enhance combustion performance but also to effectively suppress slagging. [Conclusion] Blended coal combustion technology can synergistically improve combustion efficiency and anti-slagging ability by optimising the ratio (e. g. 25%~50% Xinjiang coal + medium-high calorific value coal). Mixing medium-high calorific value blended coal or high sulfur coal can significantly improve the ash melting temperature. This study provides a key technical basis for the large-scale clean utilisation of high alkali coals in Xinjiang.