Method and System for Converting Non-Methane Hydrocarbons to Recover Hydrogen Gas and/or Methane Gas Therefrom

A method for forming at least one of (i) a hydrogen gas stream and (ii) a product gas stream from a hydrocarbon gas feed stream comprising one or more non-methane hydrocarbons, water, and optionally methane, the method comprising:

• feeding the hydrocarbon gas feed stream to a hydrocarbon conversion system comprising a heavy hydrocarbon reforming (HHR) module comprising:
• a first inlet for receiving the hydrocarbon gas feed stream;
• a first outlet for delivering a platform gas comprising methane and hydrogen;
• a first reactor containing a first catalyst and being adapted to receive the hydrocarbon gas feed stream in fluid communication with the first reactor, wherein the first reactor and the first catalyst are adapted to react at least a portion of the non-methane hydrocarbons in the hydrocarbon gas feed stream into carbon oxides, hydrogen, methane, and water, thereby forming a first reformate comprising the carbon oxides, the hydrogen, the methane, and water;
• and
• a cooler adapted to (i) receive the first reformate from the first reactor in fluid communication with the cooler, and (ii) separate at least a portion of the water from the first reformate, thereby providing (i) a dried first reformate in fluid communication with the first outlet as the platform gas and (ii) a recycled system water stream;
• receiving the hydrocarbon gas feed stream at the first inlet;
• feeding the hydrocarbon gas feed stream having a selected steam:carbon ratio to the first reactor having a selected reaction temperature to react at least a portion of the non-methane hydrocarbons in the hydrocarbon gas feed stream, thereby forming a first reformate comprising carbon oxides, hydrogen, methane, and water, wherein:
• the steam:carbon ratio in the hydrocarbon gas feed stream fed to the first reactor and the reaction temperature in the first reactor are selected between (A) first operating conditions favoring methane production in the first reactor, in the resulting first reformate, and in the resulting platform gas, and (B) second operating conditions favoring hydrogen production in the first reactor, in the resulting first reformate, and in the resulting platform gas;
• the steam:carbon ratio for the first operating conditions is up to 2.6, and the reaction temperature for the first operating conditions is characterized by an inlet temperature to the first reactor in a range of 400° C. to 550° C.;
• and
• the steam:carbon ratio for the second operating conditions is in a range of 3 to 8, and the reaction temperature for the second operating conditions is characterized by an inlet temperature to the first reactor in a range of 450° C. to 800° C.;
• separating at least a portion of the water from the first reformate in the cooler, thereby providing (i) a dried first reformate and (ii) a recycled system water stream;
• delivering the dried first reformate as a platform gas via the first outlet, the platform gas comprising at least one of (i) a hydrogen gas stream and (ii) a product gas stream;
• and
• optionally adding an additional product stream to at least one of the hydrogen gas stream and the product gas stream, thereby forming a designer fuel stream having a selected composition.