热解-重整-燃烧解耦的煤气化特性

Gasification characteristics of coal in decoupled triple bed

采用热解、重整、燃烧解耦分离的解耦三床气化(decoupled triple bed gasification,DTBG)系统,以橄榄石为原位焦油裂解催化床料,进行了煤催化气化实验。研究了煤种、煤进料速率、重整器温度以及水碳比(S/C)对煤热解焦油裂解/重整反应的影响。结果显示:随着煤挥发分含量增加,气体产率、碳转化率、冷煤气效率以及产气中的H2含量增加。由于半焦不参与气化反应,导致碳转化率和冷煤气效率偏低。煤和催化剂比例的改变会影响气体产率和产气组成,当煤的进料速率从0.12 kg/h增加到0.30 kg/h时,气体产率从0.28 m^3/kg增加到0.46 m^3/kg,H2含量从28.4%增加到50.5%。重整器温度的升高有利于促进煤焦油裂解转化,从而增加气体产率。当重整器温度为850℃、S/C为1.0时,气体产率达到了0.60 m^3/kg,橄榄石催化剂有效地降低了焦油含量,焦油产率仅为2.11g/m^3。S/C的升高增强了焦油水蒸气重整反应,但引入过量的水蒸气会导致反应器内气体的流速加快,缩短了反应物的停留时间和反应时长,减缓了焦油水蒸气重整反应的反应程度。

Catalytic steam gasification of coal was carried out in a pyrolysis, reforming and combustion separateddecoupled triple bed gasification system. The olivine was used as the in-situ tar cracking catalytic bed material, andthe coal catalytic gasification experiment was carried out. The effects of coal types, coal feeding rate, reformertemperature and steam to carbon mass ratio(S/C) on gasification performance were investigated. The results showedthat the gas yield, carbon conversion, cold gas efficiency and H2 content in the gas increased with the increasingvolatile content of coal. The carbon conversion and cold gas efficiency is relatively low due to the char is notinvolved in gasification reaction. The gas yield and gas composition influenced by coal to catalyst ratio. The gas yield increased from 0.28 m^3/kg to 0.46 m^3/kg and the H2 content increased from 28.4% to 50.5% with increasingcoal feeding rate from 0.12 kg/h to 0.30 kg/h. Increasing reforming temperature and S/C were beneficial to promotethe 3 tar cracking and conversion, and thus increased the gas yield. A gas yield of 0.6 m^3/kg tar content as low as 2.11 g/m^3 has been achieved at the reformer temperature was 850℃ and S/C of 1.0. The addition of steam enhanced thesteam reforming reaction of tar, and increased the gas yield. However the excessive steamcause shorter residencetime of tar in reformer that results reduction degree of tar steam reforming reaction.