| 摘要 |
Lignite and other bulk-mined materials generally contain a significant amount of water, more than 50 per cent by weight in many cases. The enclosed water in bulk mined materials such as lignite needs costly and time-consuming treatment for its removal which is generally not cost-effective. Dehydration is generally attempted by heating the wet material using hot air. The efficiency of dehydration of bulk lignite using hot air is very low unless the lignite is firstly crushed and pulverized to improve heat penetration. This however presents serious fire and explosion risks due to the spontaneous combustion of fine carbon powders in an oxygen-containing atmosphere. All these problems make hot- air de-hydration slow, energy intensive, uneconomical and generally unacceptable. The present invention addresses all these problems by direct heating of the water inside the lignite by electromagnetic irradiation, especially Resonance Frequency or Microwave irradiation in a continuous or semi-continuous process without any need for crushing or pulverization or hot air. The method is very efficient and rapid due to the high penetrative power of such electromagnetic radiation, the preferential coupling of the radiation with water and the resulting æinside-out heating of the material. |
