K~+、Ca~(2+)和Fe~(3+)对和丰煤热解产物分布、结构及品质的影响

将K~+、Ca~(2+)、Fe~(3+)的硝酸盐用于处理脱灰和丰煤样(K-DC、Ca-DC和Fe-DC),在热重分析仪中考察了处理煤样的失重特征和气体逸出规律。结果表明,处理煤样的总失重率减少,CO_2和H_2的浓度较原煤(DC)的高。通过固定床研究了处理煤样热解过程中产物的分配规律,采用元素分析、FT-IR、模拟蒸馏和GC-MS等分析了半焦的结构特征和焦油的组成与品质。结果表明,与DC相比,处理煤样的半焦和气体产率增加,焦油产率降低,相应半焦的不饱和度和缩合程度降低。在各金属组分的作用下,焦油中的轻质组分分率增加,其中,Fe~(3+)的作用最为显著,其值增加了22.4%。GCMS结果表明,长链烷烃含量高达70%,是焦油组分重的主要原因,K和Fe组分可促进其分解。

Effects of K+, Ca2+ and Fe3+ on the distribution,structure and quality of the pyrolysis products of Hefeng coal

The nitrate solution of K⁺, Ca²⁺ and Fe³⁺ was used to treat Hefeng demineralized coal (DC) separately. The weight loss and gas evolution of coal samples were studied by thermogravimetric analyzer. It is found that the total weight loss of treated coal samples decreases, while the concentration of CO₂ and H₂ increases for treated samples. Then the distribution variation of products during the pyrolysis process of treated coal samples were investigated in a fixed bed reactor together with the analyses of elemental analysis, FT-IR, simulated distillation and GC-MS. The results indicate that the char and gas yields of treated coal samples rise, while the tar yields decline. The unsaturation and condensation of corresponded char samples exhibit a decreasing tendency. Under the action of these metal components, the percentage of light component in the tar increases, especially by 22.4% due to the effect of iron species. GC-MS analysis exhibits that long chain alkanes occupy about 70% of the total relatively, leading to the high content of heavy component in tar, which can be catalytically cracked by K and Fe species.