Under relatively low temperature, coal and oxygen compounds into the transient products with no gas produced.So the mass of the sample increases.And the transient products can adsorb more oxygen.

• 在较低加热温度下，煤样同氧气发生化合反应形成不稳定的中间产物使煤的质量增大，同时这些中间产物具有更强的氧气吸附能力。