No, the S/C ratio is based on the C in the hydrocarbons only. This is because the S/C ratio is meant for the reforming reaction only. The HTS and LTS reactions are not relevant to S/C ratio.
George, I also received an answer to this query from another source. Steam inlet to SMR is also used for the shift reaction (CO + H2O ---> CO2 + H2). So CO concentration should be included but not CO2.
These reactions only occur in the presence of another catalyst (chromium based)in the HTS and LTS reactors, while reforming reaction is with nickel catalyst. Some shift reaction may occur in the reformer, but kinetics will be slow in the absence of a suitable catalyst.
