整体煤气化联合循环发电系统中气化参数对气化单元性能的影响

Effects of Gasification Parameters on Performance of Gasification Unit in Integrated Gasification Combined Cycle System

整体煤气化联合循环(integrated gasification combined cycle,IGCC)发电系统中气化岛包含气化单元和净化单元,气化单元由气化炉、废热锅炉和空分分离装置组成。合成气化学能和冷煤气效率直接影响着整个IGCC电站系统效率,是衡量合成气品质和气化炉性能的关键参数。采用Thermoflex软件对200MW级IGCC气化单元进行模拟计算。着重研究水煤浆浓度、氧碳摩尔比、气化温度、气化压力对气化单元性能的影响。计算结果表明:在较低气化温度下增加水煤浆浓度有利于冷煤气效率和合成气化学能的增加。调节氧碳摩尔比对调节气化炉温度水平具有良好的灵敏性和有效性。另外,氧碳摩尔比还能够起到分配煤中化学能的作用,即调节煤中化学能在合成气化学能和物理显热之间的分配比例。采用低温、加压方式,有利于提高合成气化学能。

Gasification-island in integrated gasification combined cycle （IGCC） system contained gasification unit and depuration unit. Gasification unit is composed of gasifier, waste heat boilers and air separation. Syngas heating value and cold gas efficiency which are the key parameters to evaluate syngas quality and performance of gasifier influenced the efficiency of whole IGCC power system directly. Based on software ＂ThermoFlex＂, the gasification system of 200 MW IGCC was simulated and calculated. The effects of coal-slurry concentration, O and C＇s mol ratio ε （ε= [O]/[C]）, gasification temperature and gasification pressure on gasification system performance were mostly researched. The results show that increasing coal-slurry concentration makes for enhancing cold gas efficiency and syngas heating value at lower gasification temperature. Adjusting ε has well sensitivity and validity to adjust gasification temperature. Additionally, ε also can distribute chemistry energy of coal. Namely ε can adjust the distribution proportion between chemistry energy and physic sensible heat of syngas. Syngas heating value can be enhanced at high pressure and low temperature.