英语语法分析

The heterogeneous mechanisms may be a main contribution to NO reduction using coals as reburning fuel.

煤粉作为再燃燃料还原NO时，煤焦的异相机理起主要作用。

When oxygen volume fraction is larger than 7%, the coal reburning process is ineffective for NOx reduction.

当氧气体积分数大于7%以后，煤粉再燃过程不再具有脱硝效果。

The results of study have certain reference significance for determining optimal coal fineness required for reburning.

研究结果对确定再燃所需要的最佳煤粉细度具有一定参考意义。