| 摘要 |
<p>A drying method and a drying apparatus for lignite particle and pulverized coal after granulation. The method is: a lignite raw material is sieved and crushed into particles between 4 mm and 50 mm in particle diameter or granules of less than 4 mm are made into particles between 4 mm and 12 mm in particle diameter and then transported into a pressure vessel to be sealed; then, a low-pressure high-temperature superheated steam is introduced into the pressure vessel, the superheated steam is introduced into the pressure vessel for heat exchange with the lignite particles, and, either when the lignite particles reaches a temperature between 130°C and 290°C or when the pressure within the pressure vessel is greater than or equal to 1.5 megapascals, supply of the superheated steam is ceased and pressure stabilization is commenced; and, after 10 minutes of pressure stabilization, a modified coal heated by the superheated steam is extracted and stacked for cooling in natural conditions. The present invention uses the superheated steam as a heat medium to allow the lignite particles to be modified towards characteristics of bituminous coal. The pressure vessel of the present invention effectively ensures that the lignite particles are dried in the optimal temperature and pressure, discharges waste gas and condensed water in a timely manner, allows the dried lignite particles to be provided with significantly reduced water content and minimized re-absorption and to be free from spontaneous combustion and weathering, and provides significantly increased calorific value per unit.</p> |
