Ammonia manufacturing process

Abstract

In an ammonia manufacturing operation a normally gaseous hydrocarbon or a vaporized naphtha is steam reformed and shift converted, in the presence of air to produce a relatively hot water vapor-containing gaseous stream containing nitrogen and hydrogen in substantially stoichiometric proportion for the production of ammonia along with carbon dioxide and with minor amounts of carbon monoxide. The hot gaseous mixture is then cooled to remove water vapor therefrom as water, and oxygen, usually in the form of air, is added to the resulting cooled gaseous mixture which is contacted with a catalyst for the selective oxidation of the carbon monoxide therein to carbon dioxide in the presence of hydrogen. The oxygen is provided in part by air diverted from the steam reforming and in part by supplemental air. The resulting gases, now having a substantially reduced carbon monoxide content, are then treated for the removal of carbon dioxide and optionally to methanation to convert residual carbon oxides therein to methane. The resulting treated gases are subjected to contact with a catalyst under high pressure and at an elevated temperature for the conversion of the nitrogen and hydrogen in the treated gases to ammonia.