燃料化学学报2011，Vol.39Issue(4)：251-257,7.
CaSO4氧载体煤基合成气化学链燃烧模拟研究
Simulated investigation of chemical looping combustion with coal-derived syngas and CaSO4 oxygen carrier
摘要
Abstract
Compared to metal oxides, CaSO4 adopted as oxygen carrier (OC) in chemical looping combustion (CLC) presents several advantages such as low cost, easy availability and superior oxygen transfer capacity, whilst the SO2 emission and solid sulfur deposit in the process could be a big concern. In this study, thermodynamic simulations were conducted to investigate the sulfur distribution in a CLC system with CaSO4 as OC and syngas derived from coal as the fuel. Several findings were attained: (i) On the main products and reaction pathways in the fuel reactor (FR), at the low temperature of 100 ℃ ～400 ℃, the main sulfur species and carbon deposit were H2S and CaCO3 via the methanation of CO with H2 coupled with the shift reaction of CO with H2O(g) and the ensuing thermochemical sulfate reduction (TSR). Then at 400 ℃ ～915 ℃, CaS and CO2 were the main products through the reaction of CaSO4 with H2 or CO, and both products increased with increasing FR temperature. Furthermore, at the FR temperature higher than 915 ℃, due to the initiation of the solid side reaction between CaS and CaSO4, the percentage of CaS declined. In contrary, the percentages of CaO, H2 and CO increased possibly due to the consumption of part of CaSO4 in the side reaction and thus not enough lattice oxygen available. In the air reactor( AR), the oxidization of CaS by air into CaSO4 was always dominant. Besides at ΦAR below 0.8, both the solid side reaction of CaSO4 with CaS and the oxidization of CaS into CaO were simultaneously in effect. (ii) In the FR, the optimized condition was suggested as at around 915 ℃, atmospheric condition and carefully controlled ΦFR around unity. (iii) In the AR, sufficient supply of air was important for the oxidization of CaS, and ΦAR ≥ 1 would ensure the full oxidization of CaS into CaSO4 and prevent the emission of SO2 and formation of CaO as well. Overall, this study provided the most suitable conditions of using CaSO4 as OC in CLC of syngas with the minimal SO2 emissions and CaO formation.关键词
化学链燃烧/煤基合成气/氧载体/CaSO4/热力学模拟Key words
chemical looping combustion (CLC)/ coal-derived syngas/ oxygen carriers/ CaSO4/ thermodynamic simulation分类
化学化工引用本文复制引用
王保文,晏蓉,郑瑛,赵海波,郑楚光..CaSO4氧载体煤基合成气化学链燃烧模拟研究[J].燃料化学学报,2011,39(4):251-257,7.基金项目
Foundation item:National Natural Science Foundation of China (50906030,50936001) （50906030,50936001）
A * Star SERC Grant of Singapore (SERC 0921380025-M47070019) and partial funding from National Basic Research Program (2010CB227003,2011 CB707301). （SERC 0921380025-M47070019）
