富氧燃烧烟气中褐煤飞灰的固硫与固碳反应特性实验研究

Experimental Studies on Lignite Fly-Ash Characteristics of Sulfuration Retention and Carbonation Retention Reaction in Flue Gas of Oxy-Fuel Firing

与传统空气燃烧烟气相比,富氧燃烧烟气中SO_(2)浓度有3~4倍的提高。烟道中飞灰碱土金属更多地发生固硫与固碳反应。通过高温沉降炉实验,分析了600℃、800℃、1000℃高温下碱土金属捕捉SO_(2)与CO_(2)的规律。600~1000℃下飞灰发生固硫反应的组成主要是CaO,且温度越高固硫反应的速率越快。800~900℃下富氧烟气中会同时发生灰的固硫与固碳反应。800℃时,1000 ppm SO_(2)下,飞灰固硫与固碳反应同时发生。在1500 ppm SO_(2)浓度下,固硫反应会抑制固碳反应。研究对富含CaO的飞灰再利用、炉内高温干法脱硫等有一定的理论指导意义。

Compared with traditional air firing of pulverized coal,SO_(2) concentration is generally enhanced by around 3-4 times in the flue gas of oxy-fuel firing,as thereby promotes more sulfur retention of alkaline earth metal in fly-ash of lignite.A series of experiments were conducted on the bench of drop-tube furnace to analyze the mechanism under 600,800 and 1000℃.The main conclusion includes:Active CaO in ash is key to capture SO_(2) under higher temperature.At 800-900℃,the ash-sulfur and carbon-fixing reactions will occur simultaneously in the oxygen-enriched flue gas.With higher concentration of SO_(2),,like 1500 ppm,carbonation process of ash is inhibited by the sulfuration reaction under 800℃.The research has certain theoretical guiding significance for the reuse of CaO-rich fly-ash and the high temperature dry desulfurization in the furnace.