CO气氛下褐煤加压快速热解过程中CH_4的逸出规律

在管式反应器上进行了霍林河褐煤加压快速热解实验,研究了CO气氛下CH4逸出规律。在加压快速热解条件下,由于CO解离态吸附的O(a)吸附在煤上,提供了活性中心,电负性强的O(a)诱发其周围其他原子的电子云向O(a)偏移,减弱了原来化学键的强度,导致芳香环的开裂,侧链、醚键和脂肪链的断裂提供更多的自由基,稳定煤热解生成的碎片,促进了CH4的生成和逸出。因此,CO气氛下CH4产率较N2气氛下的高,在900℃、1.0 MPa时,50%CO气氛下的CH4产率较N2气氛下的提高了12.5%,并且CH4产率随着温度升高、压力的增大而增大。

CH4 release character from pressurized fast pyrolysis of lignite in CO atmosphere

Fast pyrolysis of Huolinhe lignite was carried out under pressure in a tubular reactor, and the CH₄ evolution at CO atmosphere was examined. CO dissociation state O(a) adsorbed on coal is an active center. The stronger electronegative O could induce the electron cloud of other atoms around O(a) atom to offset to it, which could weaken the strength of original chemical bonds and promote their breaking. These result in the cracks of the aromatic ring, side chain, ether linkages and aliphatic chain in the char, which could produce more free radicals. The free radicals could stabilize the fragments produced in the pyrolysis, and lead to more CH₄ generated and involved. Therefore, the CH₄ yield is higher under CO than it in N₂. The CH₄ yield increases by 12.5% under CO compared with N₂ at 900 ℃ and 1.0 MPa. The CH₄ yield increases with raise of temperature and pressure.