Gasification characteristics and coal-nitrogen migration in a gasification-combustion mode: Influence of air-staged gas distribution
- Release Time:2025-10-16
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2025-10-16Title of Paper:
Gasification characteristics and coal-nitrogen migration in a gasification-combustion mode: Influence of air-staged gas distributionJournal:
APPLIED THERMAL ENGINEERINGSummary:
With the expanding proportion of renewable energy in power generation, coal-fired power plants are increasingly challenged by the need for peak shaving, which demands stable combustion and ultra-low NOx emission at low loads. This study explores the technology of utilizing a multi-nozzle impinging entrained-flow gasifier to convert cold pulverized coal (PC) into high-temperature gasified fuel. This process not only preemptively converts a substantial proportion of coal-N to N2 in the gasifier but also introduces high-temperature fuel into the furnace, thereby providing an innovative resolution for achieving stable combustion and low NOx emission for PC boilers operating at low loads. In this study, efforts were made to examine the impact of air-staged gas distribution strategy on the gasification and combustion characteristics, as well as the mechanism of NO formation and destruction. Besides, CFD simulations were performed to understand the flow field structure and the gasification mechanism within the gasifier. The results showed that the high temperature zone in the gasifier was mainly concentrated in the area around the burner plane. The gasifier could stably preheat cold PC to high-temperature gasified fuel (758∼876 °C) within a wide range of primary air ratio (λ1) and ensure that most of the coal-N (56.92 % ∼ 68.99 %) was converted to N2 in advance. Increasing λ1 could increase the gasifier temperature and effectively reduce the conversion of coal-N to NH3 and HCN in the gasifier, especially increasing the gasifier temperature above 1015 ℃ could greatly promoted the conversion of coal-N to N2. It is worth stressing that an optimized air distribution strategy can effectively reducing NOx emission. The optimal air-staging strategy, achieving both the lowest NOx emission (125 mg/Nm3@6%O2) and the highest combustion efficiency (99.78 %), was obtained at λ1 = 0.38 and λ2 = 0.44.Co-author:
Wang Xiaoxiao, Cui Baochong, Ruan Renhui, Wang Xuebin, Tan HouzhangVolume:
263Translation or Not:
NoDate of Publication:
2025-03-15