高炉喷吹用秸秆炭性能表征

实施碳减排是中国全面执行《巴黎协定》的承诺,利用秸秆炭替代煤粉用于高炉喷吹可实现部分碳减排。采用热分析(TG、DTG、DSC)和角锥法对热解小麦秆炭、玉米秆炭、棉秆炭、稻杆炭、2种无烟煤和1种烟煤的燃烧特性和灰熔特性进行了研究,考虑到碱负荷对高炉顺行的影响,考察了棉杆炭可替代烟煤的比例。结果表明:秸秆炭较煤粉着火点温度、燃尽点温度低,燃烧速率快,释放热量高,燃烧过程稳定,综合燃烧性能好。但秸秆炭(除了棉秆炭)碱金属含量较高,灰熔点温度较低,易结渣,替代煤粉比例不宜较高;而棉杆炭由于CaO含量较高,其灰分软化温度大于1 200℃,灰融特性较好。在不影响高炉顺行的条件下,棉杆炭可以部分替代烟煤,其喷吹量为11.37kg/t,CO2减排量可达65.7kg/t。

Performance characterization of straw charcoal used for blast furnace injection

The implementation of reduction of CO2 emissions is commitment of Chinese government for full imple-menting "Paris Agreement" ,which can be partially realized by using straw charcoal to replace pulverized coal for blast furnace injection .The ash fusion characteristics and combustion characteristics of coals and straw carbon , which includes two types of anthracites ,one type of bituminous coal ,four sorts of straw charcoals which are wheat straw carbon ,corn stalk carbon ,cotton stalk carbon and rice straw charcoal ,were analyzed through the TG-DTG-DSC technology and by triangulation method .Considering the effect of alkalis load on normal operation of blast furnace ,the proportions of cotton stalk charcoal to substitute bituminous coal were also investigated .The experimental results indicate that the combustion characteristics of straw charcoals are better than pulverized coal due to lower ignition and burn-out point ,higher combustion rate and high release heat ,more stable combustion process and better comprehensive combustion properties .But straw charcoals ,except the cotton stalk carbon , possess low ash melting temperature and poor slagging performance because of its high content of alkali elements . Thus ,the proportions of straw charcoals to substitute pulverized coal should not be too high .The cotton stalk carbon has good ash fusion characteristics ,and its ash softening temperature is higher than 1200 ℃ due to high content of CaO .The cotton stalk carbon can partly substitute bituminous coal ,and when its injection quantity reached to 11.37 kg/t ,about 65.7 kg/t CO2 emission can be reduced .