煤热解过程中含氮产物的析出及金属离子的催化特性研究

选择3种典型煤种为研究对象,通过脱灰和添加含Fe、Ca、Na等金属盐,研究煤热解过程中金属离子对含氮气相产物析出特性的影响以及与煤种和温度的交互关联。结果表明,脱灰煤HCN和NH3的产率均比原煤样下降,而随温度的升高HCN的产率逐渐增大,NH3的产率则先增加后减小,在800℃有最大值。金属离子对不同变质程度煤的含氮气相产物析出的催化作用不同;Fe和Na抑制中等变质程度煤HCN的析出,而对低变质程度煤起促进作用,Ca则对HCN的析出均有一定的促进作用。而对于NH3的形成,3种离子均对中等变质程度煤有抑制作用,而对低变质程度的煤则有促进作用。不同金属离子对HCN和NH3析出的催化作用均有一定的范围。煤热解时含氮气相产物的析出是煤中固有多种金属离子共同作用的结果。

Release of nitrogenous products and the catalytic characteristics of metal ions during coal pyrolysis

The influence of metal ions on the release characteristics of nitrogenous pollutants from pyrolysis of 3 typical coals with different ranks were studied by demineralization and adding metal salts of Fe, Ca and Na. The interactions of coal type and temperature during coal pyrolysis were explored. The results show that yields of HCN and NH₃ from the demineralized coals are lower than that from the raw coals. The yield of HCN increases gradually with the increase of temperature, while the yield of NH₃ increases first and then decreases, with a maximum value at 800 ℃. Catalytic effects of metal ions on nitrogenous pollutants release from different ranks of coals are different. Fe and Na restrain HCN release from medium rank coals, but promote that from low rank coals, while Ca facilitates the HCN release from all coals to some extent. Three metal ions all inhibit the release of NH₃ from medium rank coals, but promote that for low rank coals. Catalysis of each metal ion on yield of HCN and NH₃ has its own range of effectiveness. Release of nitrogenous pollutants during coal pyrolysis is influenced by the interactions of many kinds of inherent metal ions in coals.