Multi-stage membrane reactor system for ammonia cracking to produce hydrogen

A method of multi-stage ammonia cracking to produce hydrogen, the method comprising:

• pressuring a feed stream comprising ammonia (NH3) to a first pressure above 3 MPa;
• using a plurality of membrane reactors, catalytically cracking the NH3 to form hydrogen (H2) and nitrogen (N2), the catalytically cracking comprising,
• cracking a first portion of the NH3 at the first pressure in a first membrane reactor, forming a first H2 product stream having a pressure above 1 MPa, and a first retentate stream comprising unreacted NH3,
• recovering the first H2 product stream as a permeate from the first membrane reactor,
• providing the first retentate stream to a subsequent membrane reactor, and
• cracking at least a portion of the unreacted NH3 in the subsequent membrane reactor at a pressure lower than the first pressure, forming a another H2 product stream.

A multi-stage membrane reactor system comprising:

• a first membrane reactor comprising a first hydrogen-selective membrane tube that defines a first permeate side and a first retentate side;
• a second membrane reactor comprising a second hydrogen-selective membrane tube that defines a second permeate side and a second retentate side, wherein the second membrane reactor is fluidically connected and downstream to the first retentate side of the first membrane reactor;
• and
• an ammonia cracking catalyst disposed within the first and second membrane reactors;
• a pressure control system connected to the first and second membrane reactors and configured to adjust pressures of feed steams.