Hydrogen production method

A method of producing a hydrogen product stream comprising:

• combining a steam stream and a hydrocarbon containing stream to produce a reactant stream and reacting hydrocarbons with steam contained in the reactant stream in a steam methane reformer to produce an intermediate product stream;
• alternatively forming the hydrocarbon stream from a first feed stream and a second feed stream without substantially changing flow rate of the steam stream and while maintaining reformer exit temperatures at both the reactant and flue gas side essentially constant and flow rate of the flue gas essentially constant;
• the first feed stream being made up of at least one of natural gas, refinery off-gas, naphtha and synthetic natural gas;
• the second feed stream being made up of a hydrogen and carbon monoxide containing gas and at least one of the natural gas, the refinery off-gas, naphtha and synthetic natural gas;
• utilizing a synthesis gas stream formed by a gasifier for the production of the hydrogen and carbon monoxide containing gas;
• subjecting the intermediate product stream to a water gas shift reaction to produce a shifted stream;
• and
• separating the hydrogen from the shifted stream in a pressure swing adsorption unit to produce the hydrogen product stream.