Cracking of a process gas

Abstract

A process gas (such as a hydrocarbon gas) is flowed through a thermal cracking apparatus to crack the process gas into constituent components (such as hydrogen gas and solid carbon nano-particles, e.g., carbon nano-onions, necked carbon nano-onions, carbon nanospheres, graphene, graphite, highly ordered pyrolytic graphite, single walled nanotubes, and/or multi-walled nanotubes). The thermal cracking apparatus has an elongated heating element disposed within an inner volume along a longitudinal axis thereof. The elongated heating element heats the process gas as it flows within a longitudinal elongated reaction zone to thermally crack molecules of the process gas into the constituent components of the molecules.

1 . A thermal cracking apparatus, comprising:
 a body having an inner volume with a longitudinal axis, the inner volume having a reaction zone concentric with the longitudinal axis;   a feedstock process gas inlet through which a feedstock process gas is flowed longitudinally into the inner volume during thermal cracking operations; and   an elongated heating element disposed within the inner volume along the longitudinal axis and being surrounded by the reaction zone, wherein the elongated heating element is held in tension by a biasing element;   wherein, during the thermal cracking operations, the elongated heating element is heated by electrical power to a molecular cracking temperature to generate the reaction zone, the feedstock process gas is heated by heat from the elongated heating element, and the heat thermally cracks molecules of the feedstock process gas that are within the reaction zone into constituent components of the molecules.   
     
     
         2 . The thermal cracking apparatus of  claim 1 , wherein:
 the body further comprises a shell and a heating chamber disposed within the shell; and   the heating chamber defines the inner volume and contains the reaction zone along the longitudinal axis.   
     
     
         3 . The thermal cracking apparatus of  claim 2 , wherein:
 the shell and the heating chamber define a preheating region in a space between the shell and the heating chamber;   the feedstock process gas is flowed through the preheating region before it is flowed into the inner volume during the thermal cracking operations; and   the feedstock process gas is preheated by heat transferred through the heating chamber from the reaction zone during the thermal cracking operations.   
     
     
         4 . The thermal cracking apparatus of  claim 3 , wherein:
 the feedstock process gas cools the heating chamber when flowed through the preheating region during the thermal cracking operations.   
     
     
         5 . The thermal cracking apparatus of  claim 1 , wherein:
 the elongated heating element is disposed concentrically with the longitudinal axis.   
     
     
         6 . The thermal cracking apparatus of  claim 1 , wherein:
 the elongated heating element further comprises a plurality of heating filaments arranged symmetrically at locations around and parallel to the longitudinal axis.   
     
     
         7 . The thermal cracking apparatus of  claim 1 , wherein:
 the inner volume has a cylindrical shape with a constant diameter along the longitudinal axis.   
     
     
         8 . The thermal cracking apparatus of  claim 1 , wherein:
 the inner volume has a conical shape with an inwardly tapering diameter in a direction of flow of the feedstock process gas along the longitudinal axis.   
     
     
         9 . A thermal cracking apparatus, comprising:
 a body having a heating chamber disposed within a shell, the heating chamber defining an inner volume with a longitudinal axis, the inner volume having a reaction zone concentric with the longitudinal axis;   an elongated heating element disposed within the inner volume along the longitudinal axis and being surrounded by the reaction zone;   electrodes electrically connected to the elongated heating element to provide electrical power to the elongated heating element to heat the elongated heating element to a molecular cracking temperature to generate the reaction zone during thermal cracking operations;   a gas inlet through which a hydrocarbon gas is flowed longitudinally into the inner volume, wherein the hydrocarbon gas is heated by heat from the elongated heating element, which thermally cracks molecules of the hydrocarbon gas that are within the reaction zone into hydrogen and carbon nano-particles, during the thermal cracking operations; and   a gas preheating region between the heating chamber and the shell through which the hydrocarbon gas is flowed to preheat the hydrocarbon gas and cool the heating chamber before the hydrocarbon gas is flowed into the inner volume during the thermal cracking operations.   
     
     
         10 .- 27 . (canceled) 
     
     
         28 . The thermal cracking apparatus of  claim 1 , wherein the biasing element comprises a spring. 
     
     
         29 . The thermal cracking apparatus of  claim 1 , wherein the biasing element is configured to compensate for thermal expansion or contraction of the elongated heating element, maintaining the elongated heating element in a position that is concentric with and parallel to the longitudinal axis during the thermal cracking operations. 
     
     
         30 . The thermal cracking apparatus of  claim 1 , wherein the elongated heating element comprises a plurality of wire filaments twisted together. 
     
     
         31 . The thermal cracking apparatus of  claim 1 , wherein the constituent components include solid products. 
     
     
         32 . The thermal cracking apparatus of  claim 9 , wherein the elongated heating element is held in tension by a biasing element. 
     
     
         33 . The thermal cracking apparatus of  claim 32 , wherein the biasing element comprises a spring. 
     
     
         34 . The thermal cracking apparatus of  claim 32 , wherein the biasing element is configured to compensate for thermal expansion or contraction of the elongated heating element, maintaining the elongated heating element in a position that is concentric with and parallel to the longitudinal axis during the thermal cracking operations. 
     
     
         35 . The thermal cracking apparatus of  claim 9 , wherein the elongated heating element comprises a plurality of wire filaments twisted together. 
     
     
         36 . The thermal cracking apparatus of  claim 9 , wherein the constituent components include solid products.