Decarbonisation of a chemical plant

A method for retrofitting a chemical plant which is initially arranged such that a hydrocarbon-containing off-gas stream is combusted to provide at least some of the heating duty on the chemical plant, the method comprising the step of:

• installing an off-gas treatment unit arranged to accept said hydrocarbon-containing off-gas stream, the off-gas treatment unit comprising sequentially:
• (i) a gas-heated reformer and an autothermal reformer, arranged to accept a hydrocarbon-containing fuel stream comprising hydrocarbons and produce a reformed gas stream, and arranged such that gases from the outlet of the autothermal reformer are used to provide heat required for steam reforming in the gas-heated reformer;
• (ii) a water-gas shift section arranged to accept said reformed gas stream and produce a shifted gas stream;
• and
• (iii) a CO2 removal unit arranged to accept said shifted gas stream and produce a CO2 rich stream and a decarbonised fuel stream;
• wherein said hydrocarbon-containing fuel stream is derived from said hydrocarbon-containing off-gas stream, steam and any supplemental fuel;
• wherein said off-gas treatment unit is arranged such that the decarbonised fuel stream, optionally having first undergone further purification, is combusted instead of the hydrocarbon-containing off-gas stream.