Process For The Purification Of A Carbon Dioxide Stream With Heating Value And Use Of This Process In Hydrogen Producing Processes

摘要

The present invention relates to a process for purifying a CO₂ rich gas stream in a catalytic oxidizer. In this process, flammable contaminants that are present in the CO₂ rich gas stream are oxidized when the CO₂ rich gas stream is injected along with a precisely measured amount of substantially pure oxygen into the catalytic oxidizer. As a result, a purified CO₂ rich gas stream is produced which depending upon the amount of oxygen injected contains only minor traces of residual oxygen or minor traces of the flammable contaminants. This process is useful for purifying high-pressure residue streams from membrane water-gas shift reactors, membrane reformers, or sorbent enhanced reformers, where the pressurized CO₂ rich gas stream also contains amounts of hydrogen, methane, and carbon monoxide. The process is also suitable for purifying CO₂ permeate streams from reverse selectivity polymeric membranes that are used to separate CO₂ from gas mixtures that contain CO₂, H₂ and CH₄. In a further embodiment of the present invention, the inlet and outlet temperature of the catalytic oxidizer can be controlled by recycling part of the purified CO₂ rich gas stream to the catalytic oxidizer inlet and/or injecting additional fuel into the catalytic oxidizer. Thereby, a useful amount of heat can be extracted and returned for use anywhere in the CO₂ generating process. The heat obtained via the present process may also be utilized in other processes.