There is provided a method for loading solid particles into a multi-tube reactor having an upper tube-sheet holding together the upper ends of the multitude of reactor tubes, the method comprising positioning a loading device having a plurality of holes on top of the upper tube-sheet such that the loading device rests on and substantially covers the upper tube-sheet and the holes correspond to the reactor tubes, the loading device comprising a plurality of adjacent polygonal plates, each polygonal plate having from 1 to 30 holes, each hole corresponding to one reactor tube; pouring the particles over the combined polygonal plates covering the tube-sheet; sweeping the particles through the holes in the plates into the respective reactor tubes; removing residual particles and any dust remaining on and between the plates; and removing the loading device.