宜宾煤中氮的形态及其变迁规律研究

Investigation of Nitrogen Functionality in Yibin Coal and Its Char

利用X射线光电子能谱(XPS),研究了宜宾煤及其煤焦中氮的官能团结构,分析了氮官能团在热解过程中的迁移.所有煤焦在马弗炉上制取,制焦温度分别为700、900、1100℃ 研究结果表明,宜宾煤中氮的官能团有4种,即吡啶(N 6)、吡咯(N 5)、质子化吡啶(N Q)和氮氧化物(N X),其中吡咯含量最大,煤中的N X就是N O,是煤中吡啶结构氮与氧直接结合的结果 在700℃热解时,由于煤的脱氧脱氢,吡啶酮和N O均向吡啶转化,N Q基本不变 当热解温度升高到1100℃时,N Q完全分解,残留在煤焦中的氮为吡啶结构,当有氧气存在时被氧化成吡啶酮和N

The functionalities of nitrogen in Yibin coal and in whose chars are determined by Xray photoelectron spectroscopy (XPS). The chars are prepared at 973 K, 1 173 K and 1 373 K respectively in an electric muffle furnace. The nitrogen in the coal exists in the forms of pyridine(N6), pyrrolic and pyridone(N5), quaternary nitrogen (NQ) and nitrogen oxides (NO). The NQ near 4015 eV is assigned to a protonated or oxide form of pyridinic nitrogen. On this basis, the nitrogen in sixmembered rings is the dominant in Yibin coal. It is interesting to note that NQ only exists in the char at 1 173 K, while does not exist in the char at 1 373 K. NQ can be destroyed completely at a temperature below 1 218 K, and there are two forms of nitrogen left in the product, i.e. N5 and NX, due to the oxidation of pyridinic nitrogen.