Systems and methods for regulating heating assembly operation through pressure swing adsorption purge control

A hydrogen-generation assembly, comprising:

• a fuel processing system including at least one hydrogen-producing region adapted to receive at least one feed stream and to produce a mixed gas stream containing hydrogen gas and other gases therefrom;
• a pressure swing adsorption assembly adapted to receive the mixed gas stream and to produce a product hydrogen stream containing at least substantially pure hydrogen gas and having a reduced concentration of the other gases than the mixed gas stream, and to produce a byproduct stream containing at least a substantial portion of the other gases, wherein the pressure swing adsorption assembly includes a plurality of adsorbent beds adapted to separate the mixed gas stream into streams forming the product hydrogen stream and the byproduct stream, and further wherein the pressure swing adsorption assembly includes means for selectively distributing a volume of purge gas to the adsorbent beds responsive to a predetermined flow profile having at least one portion in which the flow rate of purge gas is less than an average flow rate of the purge gas delivered during the purge step, and at least one portion in which the flow rate of purge gas is greater than the average flow rate of the purge gas delivered during the purge step;
• and
• a heating assembly adapted receive and combust the byproduct stream to produce a heated exhaust stream adapted to heat at least the hydrogen-producing region.

A method for regulating the temperature of a hydrogen-producing region of a fuel processing system adapted to produce a mixed gas stream containing hydrogen gas and other gases;

• producing a mixed gas stream containing hydrogen gas and other gases in a heated hydrogen-producing region of a fuel processing system;
• delivering the mixed gas stream to a pressure swing adsorption assembly having a plurality of adsorbent beds containing adsorbent and adapted to produce a byproduct stream containing at least a substantial portion of the other gases and a product hydrogen stream containing a greater concentration of hydrogen gas than the mixed gas stream;
• adsorbing the other gases from the mixed gas stream to produce a product hydrogen stream containing a greater concentration of hydrogen gas than the mixed gas stream;
• depressurizing the adsorbent beds to facilitate desorption of the other gases from the adsorbent;
• purging the adsorbent beds with a flow of purge gas to further facilitate desorption of the other gases, wherein the depressurizing and purging steps produce gas streams from which the byproduct stream is formed;
• combusting the byproduct stream with air in a heating assembly adapted to produce a heated exhaust stream;
• heating the hydrogen-producing region of the fuel processing system with the heated exhaust stream;
• and
• regulating the flow rate of purge gas to the adsorbent beds to produce a sufficient flow of byproduct gas to maintain the hydrogen-producing region within a determined temperature range for producing the mixed gas stream.