煤粉再燃过程再燃煤比脱硝量的实验研究

Experimental Investigation on Specific NO Reduction Quantity for Coal Reburning Process

对于煤粉再燃过程,定义单位质量再燃煤粉还原NO量为比脱硝量。在煤粉携带炉上进行再燃实验。对不同工况下NO还原效率与比脱硝量进行对比研究,分析O2浓度、再燃燃料比与煤粉细度对比脱硝量的影响规律。实验与分析结果表明:NO还原效率高并不意味比脱硝量高;NO还原效率随O2浓度降低和再燃燃料比增加而单调增加,但比脱硝量变化规律相对复杂。不同细度煤粉达到最高比脱硝量的工况不同。过量空气系数为0.3～0.65的范围为高比脱硝量区。煤粉粒径减小、反应时间增加导致NO还原效率与比脱硝量增加。

For coal reburning process, the NO reduced by unit mass of coal is defined as specific NO reduction quantity. Experiments on coal reburning were carried out on an entrained flow reactor. The comparisons of NO reduction efficiencies and specific NO reduction quantities under different conditions were made. The influences of oxygen, reburn fuel fraction and coal particle size on specific NO reduction quantity were analyzed. The result show that high NO reduction efficiency does not absolutely mean high specific NO reduction quantity; decreased oxygen content and increase reburn fuel fraction lead to increase NO reduction efficiency but not absolutely increase specific NO reduction quantity. The highest specific NO reduction quantity can be got under different conditions for coals with different particle sizes. The stoichiometric excess air region of 0.3-0.65 is a high specific NO reduction quantity region. Decreased coal particle size and increased reaction time lead to increased specific NO reduction quantity.