碱/碱土金属对煤热解半焦燃烧特性的影响  

Effects of alkali and alkaline metal on combustion characteristicsof coal pyrolysis semi-coke

作　　者：郑洪岩 黄有航 曾浩 赵消旭 冯智皓 侯冉冉 白宗庆[2] ZHENG Hongyan;HUANG Youhang;ZENG Hao;ZHAO Xiaoxu;FENG Zhihao;HOU Ranran;BAI Zongqing(Department of Chemistry and Chemical Engineering,Taiyuan Institute of Technology,Taiyuan 030008,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China)

机构地区：[1]太原工业学院化学与化工系,山西太原030008 [2]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001

出　　处：《洁净煤技术》2021年第4期62-67,共6页Clean Coal Technology

基　　金：国家重点研发计划资助项目(2017YFB0602002)。

摘　　要：低温热解提油-半焦燃烧可以实现低阶煤的梯级高效利用,是目前低阶煤高效利用的研究热点。由于热解半焦挥发分低,导致其燃点高、难燃尽,而添加助燃剂是改善低挥发分煤热解半焦燃烧特性的有效途径。采用热重法研究了碱金属(K_(2)CO_(3))和碱土金属(CaCO_(3))添加剂对半焦燃烧特性的影响,并利用Kissinger-Akahira-Sunose(KAS)模型对不同条件下的燃烧活化能进行研究。结果表明,半焦着火温度高、燃烧性能差,半焦中碱性矿物质对其燃烧性能有一定催化作用;CaCO_(3)的添加对半焦燃烧特征参数的影响不大,说明其对半焦燃烧性能的促进作用不明显;与碱土金属CaCO_(3)不同,添加碱金属K_(2)CO_(3)能显著降低煤热解半焦的燃点、最大燃烧峰温及燃烧指数;同时随着K_(2)CO_(3)添加比例的增加,半焦表观燃烧活化能显著降低,说明其能明显促进半焦的燃烧反应性;在本研究试验条件下,添加2%K_(2)CO_(3)对改善半焦燃烧性能效果最好,同时采用浸渍法添加K_(2)CO_(3)的分散效果更好,因此相比机械混合方式,浸渍法添加K_(2)CO_(3)更能改善半焦的燃烧特性。Pyrolysis to recover oil accompanied by semi-coke combustion can realize the high-efficiency and staged utilization of low-rank coal,which is the research hotspot of high-efficiency utilization of low rank coal.However,because of its low volatile,the ignition temperature of semi-coke is high,and it is hard to burn out as well.The addition of flux is a promising method to improve the combustion properties of the hard-to-burn semi-coke with low volatile.In this paper,the effects of alkali(K_(2)CO_(3))and alkaline metal(CaCO_(3))on the combustion characteristics of semi-coke were studied by thermogravimetric analysis,and the activation energy of the semi-coke combustion were investigated by Kissinger-Akahira-Sunose(KAS)model.The results show that the semi-coke has the high ignition temperature and low combustion reactivity.The inherent mineral matters in semi-coke have some catalytic effects on its combustion performance.The addition of CaCO_(3) has little promotion effect on the characteristics of semi-coke combustion,which indicates that CaCO_(3) does not improve its combustion properties.However,compared with alkali earth metal CaCO_(3),the addition of K_(2) CO_(3) obviously lowers the ignition temperature,the peak temperature of combustion and the combustion index.At the same time,with the increase of addition ratio of K_(2)CO_(3),the apparent activation energy of semi-coke combustion decreases obviously,which means that the addition of K_(2)CO_(3) can apparently improve the combustion reactivity of semi-coke.2%addition of K_(2)CO_(3) shows the best improvement for the combustion of semi-coke in this experiment,and the dispersion effect of adding K_(2)CO_(3) by impregnation method is better.In addition,the addition of K_(2)CO_(3) with impregnation is more favorable for the improvement of semi-coke combustion than physical mixture.

关 键 词：半焦 燃烧 添加剂 热重分析 燃烧活化能 

分 类 号：TQ53[化学工程—煤化学工程]