Turboexpander inter-stage heating and NH3 cracking

A turbo-expanding cracking assembly for providing a flow containing hydrogen (H2) to a combustor of a gas turbine engine, the turbo-expanding cracking assembly comprising:

• a turbo-expander comprising:
• a housing;
• an inlet at an upstream end of the housing, the inlet configured to receive an ammonia containing fuel flow;
• a plurality of stages within the housing, downstream from the inlet, and configured to receive the ammonia containing fuel flow from the inlet, each stage including a rotating blade coupled to an output shaft and a fixed stator, each rotating blade configured to cause rotation of the output shaft in response to the ammonia containing fuel flow expanding through the plurality of stages;
• at least one heat exchanger within the housing and positioned within a stage or between stages and configured to transfer heat to the ammonia containing fuel flow;
• a catalyst within the housing and configured to decompose the ammonia containing fuel flow into the flow containing hydrogen (H2);
• and
• an outlet at a downstream end of the housing, the outlet configured to exhaust the flow containing hydrogen (H2) for supply to the combustor.

A gas turbine engine comprising:

• a turbo-expanding cracking assembly in communication with an ammonia-containing fuel source, the turbo-expander cracking assembly including:
• a turbo-expander comprising:
• a housing;
• an inlet at an upstream end of the housing, the inlet configured to receive an ammonia containing fuel flow from the ammonia-containing fuel source;
• a catalyst within the housing configured to decompose the ammonia containing fuel flow into a hydrogen flow containing more hydrogen (H2) than ammonia (NH3), and
• a plurality of stages within the housing, downstream from the inlet, and configured to receive the ammonia containing fuel flow from the inlet, wherein each stage of the plurality of stages includes a rotating blade coupled to an output shaft and a fixed stator, each rotating blade configured to cause rotation of the output shaft in response to the ammonia containing fuel flow expanding through the plurality of stages;
• at least one heat exchanger within the housing and positioned within a stage or between stages and configured to transfer heat to the ammonia containing fuel flow;
• an outlet at a downstream end of the housing, the outlet configured to exhaust the hydrogen flow;
• a combustor configured to receive and combust the exhausted hydrogen flow communicated from the turbo-expander cracking assembly to generate an exhaust gas flow;
• a compressor section configured to supply compressed air to the combustor;
• and
• a turbine section in flow communication with the exhaust gas flow produced by the combustor and mechanically coupled to drive the compressor section.

A gas turbine engine comprising:

• a pump in communication with an ammonia-containing fuel source, the pump configured to increase a pressure of an ammonia containing fuel flow from the ammonia-containing fuel source;
• a thermal transfer device configured to heat the ammonia containing fuel flow;
• a primary cracking assembly in communication with the ammonia containing fuel flow, the primary cracking assembly including a catalyst configured to decompose the ammonia containing fuel flow into a first fuel flow containing hydrogen (H2) and ammonia (NH3);
• a turbo-expanding cracking assembly including:
• a turbo-expander comprising:
• a housing;
• an inlet at an upstream end of the housing, the inlet configured to receive the first fuel flow from the primary cracking assembly;
• a catalyst within the housing configured to decompose the first fuel flow such that the first fuel flow contains more hydrogen (H2) than ammonia (NH3);
• a plurality of stages within the housing, downstream from the inlet, and configured to receive the first fuel flow from the inlet, wherein each stage includes a rotating blade coupled to an output shaft and a fixed stator, each rotating blade configured to cause rotation of the output shaft in response to the first fuel flow expanding through the plurality of stages;
• at least one heat exchanger within the housing and positioned within a stage or between stages and configured to transfer heat to the first fuel flow;
• and
• an outlet at a downstream end of the housing, the outlet configured to exhaust the first fuel flow;
• a secondary cracking assembly in communication with an outlet of the turbo-expander to further decompose ammonia contained within the first fuel flow to produce a second fuel flow containing hydrogen (H2) and ammonia (NH3);
• a combustor configured to receive and combust the second fuel flow to generate an exhaust gas flow;
• a compressor section configured to supply compressed air to the combustor;
• and
• a turbine section in flow communication with the exhaust gas flow produced by the combustor and mechanically coupled to drive the compressor section.