AUTOTHERMAL CFB MEMBRANE REFORMER FOR HYDROGEN PRODUCTION FROM HEPTANE

摘要

Hydrogen is well recognized as the clean fuel of the future.Hydrogen production by steam reforming of heptane is investigated in a novel autothermal circulating flui-dized bed (CFB) membrane reformer.Pseudo-steady-state simulations show that when the catalyst is not regenerated,the nickel reforming catalyst deactivates quickly,especially at high temperatures.Continuous catalyst regeneration keeps the catalyst activity high (approx 1.0) and autothermal operation for the entire adiabatic reaction-regeneration process is achievable when the exothermic heat generated from the catalyst regenerator is sufficient to compensate for the endothermic heat consumed in the riser reformer.For this process autothermal operation is the most efficient.This type of autothermal operation requires careful optimization of the steam to carbon ratio.This ultra-efficient reforming process also shows bifurcation behavior,dictating tight control.Multiplicity occurs when steam to carbon (S/C) ratio is in the range of 1.444-2.251 mol/mol.The maximum net hydrogen yield is quite high approaching 15.6 moles of hydrogen per mole of heptane fed at the lower steady-state when S/C feed ratio is close to 1.444 mol/mol.