Method for producing synthesis gas
A method for reforming hydrocarbon-containing feed gas into synthesis gas, involving processing of the feed gas by pre-reforming at least partially converting one or more higher hydrocarbons into methane, and heating the feed gas by exothermic catalytic partial oxidation of hydrocarbons before the introduction thereof into the main reforming zone, and, subsequent to the pre-reforming, reforming the pre-reformed product with the addition of a controlled quantity of an oxidizing agent.
1. A process for producing synthesis gas from hydrocarbonaceous feed gas, the process comprising:
prereforming the feed gas comprising a higher hydrocarbon, in a prereforming zone, at a temperature in a range of from 470 to 500° C., to at least partly convert the higher hydrocarbon into methane; and
heating the feed gas, before introduction of a pre-reformed effluent into a main reforming zone, by exothermal catalytic partial oxidation of the hydrocarbon under partial oxidation conditions and by adding a controlled amount of an oxidizing agent, to obtain the pre-refomied effluent; and
reforming the pre-reformed effluent in a separate reactor from the prereforming zone, to obtain a synthesis gas comprising a carbon oxide and hydrogen, in the main reforming zone,
wherein catalysts for the exothermal catalytic partial oxidation and for the prereforming are present in at least one common fixed bed traversed by the feed gas.
2. The process of claim 1 , Wherein the main reforming zone comprises a steam reformer (SMR), an autothermal reformer (ATR), or combinations or interconnections of both.
3. The process of claim 2 , wherein the autothermal reformer is present and a feed gas temperature is raised by the exothermal catalytic partial oxidation to such an extent that the pre-reformed effluent ignites spontaneously on entry into the autothermal reformer with the addition of additional oxygen.
4. The process of claim 1 , wherein the oxidizing agent comprises air, oxygen-enriched air, or oxygen.
5. The process of claim 1 ,
wherein the catalysts comprise a metal of periodic table group 8, 9, or 10 (sub-group VIII), or a mixture of two or more of any of these.
6. The process of claim 1 , wherein, before carrying out the exothermal catalytic partial oxidation, the feed gas is preheated to a temperature of at least 250° C.
7. The process of claim 1 , wherein a feed gas temperature increase effected by the exothermic catalytic partial oxidation is controlled by an added amount of the oxidizing agent.
8. The process of claim 1 , wherein the catalysts comprise rhodium.
9. The process of claim 1 , wherein the catalysts comprise rhodium dioxide.
10. The process of claim 1 , wherein, before carrying out the exothermal catalytic partial oxidation, the feed gas is preheated to a temperature of at least 400° C.
11. The process of claim 1 , wherein the main reforming zone comprises a steam reformer (SMR).
12. The process of claim 1 , wherein the main refhrming zone comprises an autothermal reformer (ATR).
13. The process of claim 1 , wherein the main reforming zone comprises a steam reformer (SMR) and an autothermal reformer (ATR) in series.
14. The process of claim 1 , wherein all the pre-reformed effluent is passed to the separate reactor from the prereforming zone.
15. The process of claim 1 , wherein the feed gas comprises evaporated naphtha.
16. The process of claim 1 , wherein the catalysts comprise nickel.