Ammonia decomposition reactor, hydrogen production apparatus and method for producing hydrogen using the same

A method for producing hydrogen comprising:

• introducing a first gas stream comprising ammonia into a first chamber;
• partially decomposing ammonia at a temperature of 410° C. or lower in the first chamber to produce hydrogen and nitrogen;
• introducing a second gas stream, which is discharged from the first chamber and comprises ammonia, nitrogen and hydrogen, into a second chamber, and
• partially decomposing ammonia in the second chamber to produce hydrogen and nitrogen, wherein the first chamber comprises at least one selected from the group consisting of carbon steel, low alloy steel, stainless steel, and a nickel-based alloy, and
• wherein the second chamber comprises a nickel-based alloy (NT) satisfying Equation 1 below:
• T
• ≤
• 15
• ⁢
• μm
• [
• Equation
• ⁢
• 1
• ]
• in Equation 1, T is the maximum value of nitrided depths measured from a side surface toward a central axis of a cylindrical specimen when the nickel-based alloy (NT) is prepared as a cylindrical specimen having a diameter of 2 mm and a height of 200 mm, and the cylindrical specimen is exposed to a gas stream comprising 97.2% by volume NH3, 2.1% by volume H2, and 0.7% by volume N2 in a temperature environment of 500° C. for 100 hours, and the nitrided depths am measured using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis.