NOVELTY - The hydrogen-generation assembly (46) has a fuel processing system (64), a pressure swing adsorption (PSA) assembly (73), a heating assembly, and a flow-rate regulating unit. System (64) has hydrogen-producing region(s) (70) to receive feed stream(s) (68) and produce mixed gas stream. Assembly (73) has adsorbent beds to separate mixed gas stream into streams forming product hydrogen stream (42) and byproduct stream (76).    USE - For energy producing and consuming assemblies, and in gas generation and fuel cell fields.    ADVANTAGE - The hydrogen-generation assembly has a PSA assembly which is adapted to regulate the flow of purge gas to the adsorbent beds during the purge steps of a PSA cycle. The PSA assembly produces a byproduct stream containing impurities removed from the mixed gas stream and a purge gas. The flow of purge gas is regulated to maintain the flow rate and/or fuel value of the byproduct stream at or within a determined range of threshold value. The heating assembly maintains a selected component of the hydrogen-generation assembly at a desired temperature or within a desired, or selected, temperature range.    DETAILED DESCRIPTION - The hydrogen-generation assembly (46) has a fuel processing system (64), a pressure swing adsorption (PSA) assembly (73), a heating assembly, and a flow-rate regulating unit. The fuel processing system includes hydrogen-producing region(s) (70) adapted to receive feed stream(s) (68) and to produce a mixed gas stream containing hydrogen gas and other gases. The PSA assembly is adapted to receive the mixed gas stream and to produce a product hydrogen stream (42) containing pure hydrogen gas and having a reduced concentration of the other gases than the mixed gas stream, and to produce a byproduct stream (76) containing portion of the other gases. The PSA assembly includes adsorbent beds adapted to separate the mixed gas stream into streams forming the product hydrogen stream and the byproduct stream. The heating assembly is adapted to receive and combust the byproduct stream to produce a heated exhaust stream adapted to heat the hydrogen-producing region. The flow-rate regulating unit regulates the flow rate of the byproduct stream to maintain the temperature of the hydrogen-producing region within a determined temperature range for producing the mixed gas stream. An INDEPENDENT CLAIM is included for method for regulating temperature of hydrogen-producing region of fuel processing system.    DESCRIPTION OF DRAWING(S) - The figure shows the schematic view of an energy producing and consuming assembly.    product hydrogen stream (42)    hydrogen-generation assembly (46)    fuel processing system (64)    feed stream (68)    hydrogen-producing region (70)    PSA assembly (73)    byproduct stream (76)