Abstract: The invention discloses a process and apparatus for the heating or cooling of light solid particles having a low free-fall speed, by means of flowing gas-solid exchangers. The process makes it possible to heat or cool light solid particles dispersed in a gas flow by contacting them with a countercurrent flow of heavy solid particles having a greater final free-fall speed and that are hot or cool in relation to the light particles, thus effecting a heat transfer between the particles.

Abstract: The invention has for its object a process for recovering heat from a hot gaseous current, wherein it consists in making the hos gaseous current travel countercurrent to colder solid particles comprising at least a stage made up of a stack of packing elements placed on a widely perforated support, then distributing them at the top of a second column, letting them fall countercurrent to a second colder gaseous current while their grain-from-grain separation, to recover the heat of the solid heated particles.The invention also proposes a device for using the process.