A gas conduit for venting high temperature reactor comprising a conduit portion in direct communication with the reactor for receiving gas therefrom where the conduit includes a Venturi for creating a high pressure zone in the area prior to exit of the reactor. The conduit, accordingly, has a portion having first and second diameters, where the second diameter less than the first diameter and is dimensioned in order to provide an area of high pressure in the region of the first diameter.