Radiative heat exchangers for tube segments such as heating tubes in electric impedance furnaces

Abstract

This disclosure includes electric impedance furnaces for chemical production processes and methods of heating a feedstock with the present electric furnaces. The present electric furnaces include a primary heating section; a radiative heat exchanger section comprising an exchanger housing with first and second exchanger sidewalls; and a plurality of electrically conductive reactor tubes extending through the heater housing and the exchanger housing, each reactor tube defining a flowpath and having a flanged connector at respective ends of the tube; and an electric circuit configured to electrically connect in series a longitudinal portion of each of the reactor tubes such that application of a voltage difference between a first end of the longitudinal portion of a first one of the reactor tubes and a second end of the longitudinal portion of a last one of the reactor tubes will cause electrical current to flow sequentially through the longitudinal portions of all of the plurality of reactor tubes. In some such furnaces, respective ends of the reactor tubes are electrically isolated from electrically conductive feedstock and collection manifolds, for example by flanged pipe isolation joints. In some such furnaces, one or both of the exchanger sidewalls each define channel configured to receive a fluid to absorb thermal energy from the respective exchanger sidewall. The present methods comprise: heating a feedstock using one of the present furnaces by applying a voltage difference between a first end of the longitudinal portion of a first one of the reactor tubes and a last end of the longitudinal portion of a second one of the reactor tubes to cause electrical current to flow sequentially through the longitudinal portions of all of the plurality of reactor tubes; where the voltage difference is greater than 100 volts (V); and where the current does not flow into either of the collection manifold or the feedstock manifold.

Dependencies are inferred from the claim text.