不同煤种地下气化特性研究

Characteristics of Underground Gasification of Different Kinds of Coal

在地下气化模型试验及理论分析的基础上,研究了不同煤种的地下气化特性.比较了空气连续气化及纯氧-水蒸汽气化条件下的煤气组成,并从气化煤层升温速率、气化速率、煤气产率、气化效率等方面比较了不同煤种的地下气化特性.试验结果表明,煤种的不同组成决定了空气煤气中CO,H_2,CH_4含量的不同,鼓风量影响着空气煤气的组成.在适宜的汽氧比条件下,不同煤种纯氧-水蒸汽地下气化均可以获得中热值煤气.对于试验煤种,褐煤具有高的气化活性、气化速率及低的煤气产率,其纯氧-水蒸汽气化效率达87％,最适于地下气化;瘦煤地下气化,气化煤层温度上升缓慢,其气化活性较低,气化速率变化平缓,纯氧-水蒸汽气化效率为74％,但气化过程稳定,且具有高的煤气产率,可以进行地下气化;气肥煤煤层升温速率最快,煤气产率仅次于瘦煤,但在煤挥发分析出后,气化速率减小,气化稳定性变差.

Based on UCG (underground coal gasification) model test and theoretical analysis, the characteristics of underground gasification of different coal were studied from the aspect of gas composition of air gasification and oxygen-steam gasification process, the rate of temperature increasing, gasification reaction rate, gas yield and gasification efficiency etc. The results show that air gas composition is affected by coal kind and air blast velocity. On optimum ratio of vapor to oxygen, oxygen-steam gasification of different coal can produce middle heat value gas. Lignite in test has high gasification reactivity, high gasification reaction rate and lower gas yield. It is most suitable for UCG with gasification efficiency of 87%. The test lean coal has lower rate of temperature increasing due to its lower reactivity. Its gasification rate gently changes and the efficiency of oxygen-steam gasificprocess was dit the UCG process is more stable and also has high gas yield. The test fat coal has high rate of temperature increasing and its gas yield is only lower than that of lean coal. The gasification rate of fat coal decreases after pyrolysis, which will make the UCG process unstable.