PROCESS FOR HIGH-YIELD PRODUCTION OF HYDROGEN FROM A SYNTHESIS GAS, AND DEBOTTLENECKING OF AN EXISTING UNIT

Process for debottlenecking a plant that produces hydrogen including reforming of hydrocarbons, then conversion of CO, purification of hydrogen by PSA-H2 for the production of a high-pressure gaseous stream of ultra-pure hydrogen with associated production of a low-pressure residue, the two major constituents of which are carbon dioxide and hydrogen, the debottlenecking of the plant is carried out by installing, level with the PSA residue, an EHS electrochemical cell for supplying, from the PSA residue, hydrogen and a hydrogen-depleted residue, the additional hydrogen stream recovered in the EHS cell is compressed and sent to the inlet of the PSA unit thus increasing the hydrogen production of the plant while keeping the purity of the hydrogen produced by the PSA unchanged. The invention also relates to a process and a plant for producing hydrogen having an optimized hydrogen yield.