A spacing and centering device for a rigid double-wall duct, for example of the winding type, which is intended for the transport of hydrocarbons. The rigid duct comprises two coaxial tubes which are separated by an annular space. The spacing and centering device is housed in the annular space in order to maintain a distance between the two coaxial tubes. An element made from a material having low heat conductivity and comprising an aerogel element is at least partially covered with a casing of polymer-type plastic material.