Abstract: In order to deal with lots of waste water containing tar, oil and phenols generated by fixed-bed gasification process of coal to synthetic natural gas (SNG), two integrated systems are proposed, which combine two gasification processes in fixed-bed and coal-water slurry (CWS) entrained-bed.One is that the waste water generated by fixed-bed gasification process of coal is directly used for CWS preparation and another only using waste water containing phenols without tar or oil.In coal to SNG project,they are investigated and evaluated from the view of energy, and the system of highest cold gas efficiency is analyzed from economic point of view.The results show that compared with single entrained-bed gasification process, the fixed-bed/entrained-bed integrated strategies can improve cold gas efficiency. When the ratio of handling capacity of fixed-bed/entrained-bed is 2, coal consumptions are 563 kg·km^-3 (CO+H₂+3.12×CH₄) for the first integrated gasification system and 599 kg·km^-3 (CO+H₂+3.12×CH₄) for the second one, oxygen consumptions 212 m³ O₂·km^-3 (CO+H₂+3.12×CH₄) and 206 m³O₂·km^-3 (CO+H₂+3.12×CH₄), cold gas efficiencies 84.44% and 86.74%, and total thermal efficiencies are 72.53% and 74.87% respectively.Compared with fixed-bed gasification process, the production cost of coal to SNG doesn't increase remarkably for the first integrated system, the strategy is economically available.

Key words: coal to SNG, fixed-bed gasification, entrained-bed CWS gasification, energy analysis, economic analysis

摘要： 针对煤制天然气工艺中固定床气化产生大量含有焦油、酚等难处理物质的废水,提出了将固定床气化和气流床水煤浆气化相结合的气化方式解决废水问题。考察了未分离焦油煤气水直接制浆和分离焦油后酚水再制浆的两种气化集成方式,以煤制天然气项目为基础对其进行能量与经济分析。结果表明:与单一气流床相比,固定床气化和气流床水煤浆气化耦合提高了系统冷煤气效率;当固定床与气流床水煤浆气化干基煤处理量比为2,未分离焦油煤气水直接制浆和分离焦油后酚水再制浆两种气化集成方式的气化系统煤耗分别为563 kg·km^-3(CO+H₂+3.12×CH₄)和599 kg·km^-3(CO+H₂+3.12×CH₄),氧耗分别为212 m³ O₂·km^-3(CO+H₂+3.12×CH₄)和206 m³ O₂·km^-3(CO+H₂+3.12×CH₄),冷煤气效率分别为84.44%和86.74%,总热效率分别为72.53%和74.87%,且副产焦油的气化集成方案与单一固定床气化方案相比,其天然气生产成本增加不明显,经济上可行。

关键词: 煤制天然气, 固定床气化, 气流床水煤浆气化, 能量分析, 经济分析