中文摘要：

寻找清洁燃料替代焦粉是铁矿石烧结工序中降低排放的重要途径。本文针对高木炭替代比例下烧结质量严重恶化的问题,使用燃气喷吹技术对烧结床内熔化特性进行调控。首先,分别对焦粉烧结、60%木炭烧结和0.5%甲烷喷吹烧结进行了红外热像测试。与焦粉烧结相比,60%木炭烧结的熔化区厚度明显变薄。燃气喷吹技术从上游显著拓宽了60%木炭烧结熔化区的厚度。其次,数据显示随着甲烷喷吹浓度的提高,熔化温度保持时间延长,烧结矿粉碎强度也有显著改善。此外,当喷吹浓度达到0.4%时,烧结矿强度已经高于焦粉烧结强度。进一步提高喷吹浓度至0.5%,烧结强度的增幅有所减缓,烧结时间也已经超过焦粉烧结时间。建议最佳甲烷喷吹浓度为0.4%～0.5%。

英文摘要：

In recent years, seeking for green and clean alternative fuels has become an urgent issue in the iron and steel industry as a countermeasure against global warming. However, it is widely reported that sinter strength would be weakened due to the damaged heat condition at high replacement ratio of biomass. In this paper, the gaseous fuel injection method was experimentally investigated with the aim at solving this problem. Methane concentrations of 0.0% and 0.5% are tested, keeping the total calorific heat input unchanged. A newly generated secondary combustion zone in the upstream was used to control the heat pattern of melting zone. The eight thermocouples data indicated that duration time of melting temperature increased by employing the methane injection method. With the rise of methane injection concentration, the oxygen concentration in the waste gas increased, indicating the improvement of combustion condition. Experimental results showed that it was promising to strengthen the heat pattern in sintering bed at high charcoal proportion with the secondary fuel injection method. The recommended methane injection concentration was 0.4-0.5% in iron-ore sintering process.