In order to investigate the gasification performance of coal with high water content, a two-stage fluidized bed gasification (TSFBG) system was systematically simulated by Aspen Plus to identify the effect of pre-drying for coal with its initial water content varying from 10-65 wt% on gasification performance, particularly energy efficiency. The results show that the energy efficiency based on lower heating value (LHV) (η_LHV) and higher heating value (HHV) (η_HHV) of feed coal are about 1.5%-7% and 1.5%-5% higher when coal is fed to the system directly without pre-drying. For the TSFBG system, the higher the water content, the greater the energy efficiency reduction by pre-drying. The analysis of energy allocations reveals that heat loss due to the pre-drying of coal is mainly responsible for the decrease of energy efficiency in operations with pre-drying. With an increase in the initial water content from 10 to 65 wt%, the η_LHV of the TSFBG system without the pre-drying of coal using air/steam as gasification agent reaches its maximum of about 91% at an initial water content of 26 wt%. The η_LHV and η_HHV of the TSFBG system using oxygen/steam as gasification agent increases energy efficiency by about 1%-2% compared to that using air/steam. For TSFBG using air/steam to gasify coal without the pre-drying, the preferred initial water content of coal is below 50 wt%.

中文翻译：

---

高含水煤预干燥与未预干燥两级流化床气化系统工艺分析

为了研究高含水煤的气化性能，采用 Aspen Plus 系统模拟了两级流化床气化 (TSFBG) 系统，以确定对初始含水量为 10- 的煤进行预干燥的效果。 65 wt% 的气化性能，尤其是能源效率。结果表明，基于较低热值 (LHV) (η _LHV ) 和较高热值 (HHV) (η _HHV )的能效) 当煤直接送入系统而没有预干燥时，进料煤的约 1.5%-7% 和 1.5%-5%。对于 TSFBG 系统，含水量越高，预干燥对能效的降低越大。能源分配分析表明，煤炭预干燥造成的热损失是预干燥操作中能源效率下降的主要原因。随着初始含水量从 10 wt% 增加到 65 wt%，未使用空气/蒸汽作为气化剂对煤进行预干燥的 TSFBG 系统的 η _LHV在初始含水量为 26 时达到其最大值约 91%重量％。η _LHV和 η _HHV与使用空气/蒸汽相比，使用氧气/蒸汽作为气化剂的 TSFBG 系统的能效提高了约 1%-2%。对于使用空气/蒸汽在没有预干燥的情况下气化煤的 TSFBG，煤的优选初始含水量低于 50 wt%。