Abstract: The present invention provides a method and plant for the pneumatic transportation of solid particles in the form of a diluted phase through a conduit (1), with which the transport air in said conduit is given a velocity which is at most equal to the air velocity chosen for a maximum particle load level. The free flow from the pressurized air source (3) is regulated on the basis of measured air velocity or on the basis of a state corresponding thereto, such as air pressure in the conduit, and an established relationship between the free flow and the said measured velocity of the air or a state (pressure) corresponding thereto, essentially independently of the particle load. There is thus maintained in the conduit a preferably constant transport air velocity with all different occurring levels of particle load.