Process Condensate Methanol and Ammonia

The process eondensate from a standard hydrogen plant contains impurities sueh as dissolved gases, ammonia, methanol, and traces of other organic compounds. The dissolved gases that are found in the process condensate consist of the components in the syngas (CO, CO2, H2, CH4, and N2). Henry s Law can be used to calculate the amounts of these gases that are in the condensate. 

H is Hemy s Law Constant X is Mole Fraction of Component in Solution 

The CO2 represents the largest amount of dissolved gas in the eondensate, typically in the range of several 1000 ppmw. The dissolved H2, CO, and CH4 are typically in lower eoneentrations of less than a hundred ppmw eaeh. 

Ammonia formation is lessened due to the fact that the residence time of the steam methane reformer is designed for hydrogen production not ammonia production with recycle. In an NH3 plant, the ammonia is considered to be at equilibrium in a secondary reformer that is operating approximately 300°F to 500°F higher than a traditional steam methane reformer. Therefore for calculations, the worst case for ammonia production in a hydrogen plant can be assumed to be equilibrium at the reformer outlet temperature plus an additional 300°F. 

Methanol is produced as a by-product in the shift converters within the hydrogen plant. In High Temperature Shift Converters (HTSC), the formation of methanol is an equilibrium reaction similar to that of ammonia formation in the reformer. The equilibrium reaction for methanol is given below. 

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