Method of generating high-purity nitrogen gas

A method of generating high-purity nitrogen gas, comprising the steps of

• operating a fuel cell device having a cathod side and an anode side, including the sub-steps of
• passing an air stream through the cathode side of the fuel cell device,
• feeding a gaseous fuel stream to the anode side of the fuel cell device, and
• electrochemically combining oxygen from the air stream in the fuel cell device with fuel from the fuel stream, with attendent formation of a cathode exhaust gas stream containing nitrogen and residual oxygen, and generation of electric power;
• controlling said passing step;
• and
• reducing at least the residual oxygen content of the cathode exhaust gas stream to a level at which the cathode exhaust gas constitutes the high-purity nitrogen gas, including at least one of the sub-steps of
• performing said controlling step in such a manner as to optimize the oxygen utilization at the cathode side of the fuel cell device even at the expense of reducing the amount of electric power generated relative to the optimum electric power generation operating conditions of the fuel cell device, and
• removing most of the residual oxygen from the cathode exhaust gas stream exhausted from the cathode side of the fuel cell device, while maintaining both oxygen and nitrogen contained in the cathode exhaust gas in their gaseous states throughout.