掺烧零碳燃料氨是一种现实可行的燃煤发电减碳技术手段。以某40MW煤粉燃烧试验炉为研究对象,基于数值模拟研究了煤粉大比例掺烧氨且不采用深度空气分级条件下,纯氨或氨/空气混合气从煤粉火焰区不同位置(根部火焰区、中部火焰区及尾部火焰区)送入炉内时燃烧及NO生成特性。结果表明,无论是纯氨还是氨/空气混合气送入炉内,均使飞灰含碳量略有增加;由于主燃区氧量相对充足,混氨燃烧NO生成显著且出口NO浓度高于单煤燃烧。在纯氨送入方式下,随喷氨位置由煤粉火焰根部区逐渐下移至煤粉火焰尾部区,飞灰含碳量和出口NO浓度逐渐降低。然而,在氨/空气混合气送入方式下,随喷氨位置由煤粉火焰根部区移动至煤粉火焰尾部区,飞灰含碳量和NO浓度逐渐增加。综合考虑燃尽及NO排放特性,纯氨送入时建议由煤粉火焰尾部区送入炉内,而氨/空气混合气送入时建议由煤粉火焰根部区送入炉内,既可有效减弱掺氨对煤粉燃尽特性的影响,又可控制NO生成。

Co-firing zero-carbon fuel ammonia is a practical and feasible carbon reduction technology for coal-fired power generation.Taking a 40 MWth pulverized-coal combustion test furnace as the research object, the combustion and NO generation characteristics wereinvestigated numerically under the condition of firing the large proportion of ammonia and without adopting air stagingwhen pure ammoniaand ammonia/ air were injected into the furnace from different locations (flame-root zone, flame-middle zone and flame-tail zone) in thepulverized-coal flame zone. The results show that whether pure ammonia or ammonia/ air mixed gas is injected into the furnace, the carbon content in fly ash increases slightly. Due to the relatively sufficient oxygen content in the main combustion region,the significantNO generation is observed and the NOx concentration at the furnace outlet is higher than that of pure coal combustion. Under the pure ammonia injection method, as the ammonia injection location moves from the flame-root region to the flame-tail region, the carbon content infly ash and the NOx concentration at the furnace outlet gradually decreases. However, under the ammonia/ air mixture injection method, asthe ammonia injection location moves from the flame-root region to the flame-tail region, the carbon content in the fly ash and theNOx concentration at the furnace outlet gradually increases. Considering the burnout and NOx formation characteristics, it is recommendedto feed pure ammonia into the furnace from the tail area of the coal powder flame, and the ammonia/ air mixture is fed into the furnace fromthe flame - root region, which not only can effectively reduce the effect of co - firing ammonia on the burnout characteristics ofpulverized-coa, but also inhibit the NOx generation.

0 引言

1 燃烧炉简介

3 结果分析与讨论

   3.1 模拟结果验证

   3.2 不同煤粉火焰区位置送入炉纯氨的影响

   3.3 燃烧及NO排放特性的影响

4 结论