| 摘要 |
The converting of an existing methanol plant to make hydrogen and optionally methanol is disclosed. The converted plant utilizes the steam reformer (10) to which (a) a hydrocarbon, e.g., natural gas, or a lower alkanol, e.g., methanol, and (b) steam (water) are fed. Syngas is formed in the reformer (10). All or part of the syngas is processed in a CO converter (21) and/or a separation unit (22 & 28) to separate out carbon dioxide (24), carbon monoxide (30) and hydrogen (32). In the first mode, the CO converter (21) is isolated and the separated carbon dioxide (24) is fed either to the existing methanol synthesis loop (12) for methanol synthesis, or back into the feed to the reformer (10) to enhance carbon monoxide formation in the syngas (18). In the second mode, a lower alkanol is fed to the reformer (10), and the methanol synthesis loop (12) is shutdown and isolated from the rest of the plant. Any remaining syngas (38) not fed to the carbon dioxide separator (22) can be converted to methanol in the existing methanol synthesis loop (12) along with carbon dioxide (24) from the separator (22) and/or imported carbon dioxide (25), and hydrogen (35) from the separator (28). In the second mode, the separated carbon monoxide (30) is preferably recycled to the reformer (10) and/or to the CO converter (21) to enhance hydrogen production.
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