A feed gas composed of steam and natural gas with a volumetric ratio of steam to carbon of about 3.5 to 1 is reacted in the primary reformers of ammonia plants. The required steam is generated from heat sources within the plant and the balance is produced in auxiliary boilers. By installing a feed-gas saturator, the low-level heat from the flue gases that otherwise would be lost, can be utilized for saturating the natural gas feed with water. This will result in extra steam generation that can replace a part of the steam generated in the boiler. With this measure, more medium pressure steam is available for use in the plant. The water used for feed-gas saturation is process condensate that contains some methanol and ammonia.
This measure is applicable as a retrofit in existing plants.