Process for reforming ethanol to hydrogen-rich products
Process for selectively reforming ethanol to a hydrogen-rich product in the presence of at least one catalyst comprising a catalytically active material supported on a carrier, the process comprising the following steps in which the at least one catalyst is active: transferring a stream of ethanol and steam and a hydrogen-comprising stream, the molar ratio of ethanol to hydrogen being 0.2-1, to a dehydration/hydrogenation reactor for dehydrating ethanol to ethylene and for hydrogenating ethylene to produce an ethane-containing stream, adiabatically pre-reforming the ethane-comprising stream to a stream comprising methane, steam reforming the stream comprising methane to produce a mixture comprising hydrogen and carbon monoxide, converting the mixture comprising hydrogen and carbon monoxide from the steam reforming step under water gas shift conditions to produce a hydrogen-rich product stream.
1. Process for selectively reforming ethanol to a hydrogen-rich product in the presence of at least one catalyst comprising a catalytically active material supported on a carrier, the process comprising the following steps in which the at least one catalyst is active:
transferring a stream of ethanol and steam and a hydrogen-comprising stream, the molar ratio of ethanol to hydrogen being 0.2-1, to a dehydration/hydrogenation reactor for dehydrating ethanol to ethylene in the absence of oxygen and for hydrogenating ethylene to produce an ethane-containing stream;
subsequently adiabatically pre-reforming the ethane-comprising stream to a stream comprising methane;
subsequently steam reforming the stream comprising methane to produce a mixture comprising hydrogen and carbon monoxide; and
converting the mixture comprising hydrogen and carbon monoxide from the steam reforming step under water gas shift conditions to produce a hydrogen-rich product stream.
2. Process according to claim 1 , wherein the molar ratio of ethanol to hydrogen 0.5-1.
3. Process according to claim 2 , wherein the hydrogen-rich stream is provided by recycling a fraction of the effluent from the adiabatic pre-reforming step, the steam reforming step or the water gas shift step.
4. Process according to claim 3 , wherein the hydrogen-rich stream is provided by recycling the effluent from the steam reforming step with a recycle ratio of 15-50%.
5. Process according to claim 3 , wherein the hydrogen-rich stream is provided by recycling the effluent from the water gas shift step with a recycle ratio of 15-25%.
6. Process according to claim 1 , wherein the hydrogen-rich stream is provided by recycling a fraction of the hydrogen-rich product stream with a recycle ratio of 15-25%.
7. Process according to claim 1 , wherein the catalytically active material for the dehydration/hydrogenation step is selected from the group of Pt, Pd and Cu.
8. Process according to claim 7 , wherein the carrier is selected from the group of alumina, alumina silica, zirconia and zeolite.
9. Process according to claim 8 , wherein the zeolite is ZSM5, the zirconia is tungstated or sulphated and the alumina is gamma alumina.
10. Process according to claim 1 , wherein the dehydration/hydrogenation reactions are carried out at a temperature of at least 200° C. and a pressure of at least 1 bar gauge.
11. Process according to claim 3 , wherein the recycling is achieved by means of an ejector.
12. Process according to claim 1 , wherein the hydrogen-rich product stream is supplied to a fuel cell as the anode feed stream.