Process for reforming hydrocarbons
The invention relates to the production of synthesis gas by means of particularly a series arrangement of heat exchange reforming and autothermal reforming stages, in which the heat required for the reforming reactions in the heat exchange reforming stage is provided by hot effluent synthesis gas from the autothermal reforming stage. More particularly, the invention relates to optimisation of the operation and control of an arrangement of heat exchange reforming and autothermal reforming stages and introduction of an additional waste heat boiler.
1. A synthesis gas production plant, comprising:
first flow means for apportioning a hydrocarbon feedstock to a tube side of at least one heat exchange reformer, in which at least a portion of said hydrocarbon feedstock is reformed to produce a primary reformed gas,
second flow means for conveying said primary reformed gas,
an autothermal reformer (ATR), or catalytic partial oxidation apparatus (CPO) or a partial oxidation apparatus (PDX) communicating with said second flow means to produce hot effluent synthesis gas from said primary reformed gas,
third flow means for conveying said hot effluent synthesis gas, said third means comprising a mean for optionally adding steam to said hot effluent synthesis gas,
splitting means communicating with said third flow means for splitting said hot effluent synthesis gas into first and second synthesis gas streams,
fourth flow means for conveying said first synthesis gas stream through a shell-side of said at least one heat exchange reformer,
fifth flow means for conveying said second synthesis gas stream through a second heat exchanger, in which said second synthesis gas stream is cooled,
first control means downstream of the shell-side of said at least one heat exchange reformer, and
second control means downstream of a tube-side of said second heat exchanger for controlling the splitting of said hot effluent synthesis gas into said first and second synthesis gas streams.
2. The plant according to claim 1 , further comprising an adiabatic pre-reformer upstream the heat exchange reformer.
3. The plant according to claim 1 , further comprising a third heat exchanger arranged downstream the shell-side of the heat exchange reformer so as to further cool the first synthesis gas stream.
4. The plant according to claim 3 , comprising means for combining the cooled second synthesis gas from the second heat exchanger with the further cooled first synthesis gas from the third heat exchanger.
5. The plant according to claim 1 , wherein said first flow means for apportioning comprises a by-pass line for conveying a portion of untreated hydrocarbon feedstock directly to said second flow means, wherein said untreated hydrocarbon feedstock combines with said primary reformed gas input to said autothermal reformer (ATR), or catalytic partial oxidation apparatus (CPO) or partial oxidation apparatus (POX).