The present invention discloses a process method for preparing synthesis gas by using a
zero carbon or negative carbon emission
system. The process method comprises that: 1) first
raw material gas is subjected to desulfurization, steam is matched, pressurization and heating are performed, a reaction is performed to obtain first conversion gas, the first conversion gas is output, the output first conversion gas and
pure oxygen are mixed and then enter a two-stage furnace to react so as to obtain second conversion gas, and the second conversion gas is output from the two-stage furnace; 2) second
raw material gas is subjected to desulfurization, pressurization and heating and then is mixed with
pure oxygen and
carbon dioxide, then a reforming reaction is performed to obtain third conversion gas, and the third conversion gas is output from the reforming reactor; and 3) the second conversion gas is subjected to heat
recovery and then is mixed with the third conversion gas to form crude synthesis gas, wherein the crude synthesis gas is adopted as the subsequent synthesis gas with or without a decarbonization device. According to the present invention, the
greenhouse gas emission is reduced, the carbon efficiency is improved, the recycling of the carbon resources of the
energy source chemicals is achieved, the
hydrogen-carbon ratio of the synthesis gas achieves the ideal ratio of the downstream process requirement, and the
zero carbon or negative carbon emission of the whole
system is achieved.