Efficient low-temperature vacuum lignite upgrading device

The utility model belongs to the technical field of upgrading devices, and particularly relates to an efficient low-temperature vacuum lignite upgrading device. The quality improving box is fixedly arranged at the ends, away from the grinding box, of the multiple supporting rods; the connecting pipe is fixedly arranged between the grinding box and the upgrading box; and one of the two groups of rolling mechanisms is mounted in the material rolling box, and the other group of rolling mechanisms is mounted in the quality improving box. Brown coal is poured from a feeding port, two servo motors are started at the same time to drive rotating rollers in the upgrading box and the grinding box to rotate after pouring, the brown coal firstly passes through the rotating rollers in the grinding box, grinding teeth on the rotating rollers are used for primarily smashing the brown coal, and the smashed brown coal falls into the upgrading box through a connecting pipe; and the lignite is subjected to secondary crushing th