Natural Gas as Feedstock for Fertilizer

Abstract

Separation of the hydrogen needed for the ammonia synthesis reaction, from its source is difficult. Hydrogen production method is the main source of distinction between the various ammonia production routes. Most of the improvements in the technology regarding the ammonia synthesis were concerned with the hydrogen production step. Hydrogen can be produced by steam reforming, partial oxidation and water electrolysis. The bulk of the world ammonia production is based on steam reforming. The major hydrogen sources are natural gas, naphtha and coal. In this project different methods available for hydrogen separation from its source are analyzed and the best possible way to produce synthesis gas (which will form ammonia) from natural gas is found out. The number of reforming stages required for a plant capacity of 1500 tons per day of ammonia production is found out. The mass balance and energy balance calculations for the above said plant capacity is presented in this work. Then the conventional carbon dioxide removal process and methanation process are replaced by the advanced, economical pressure swing adsorption process. It was also found that two stages of shift converters required for this plant capacity. The number of reforming stages required is only one and nitrogen is obtained from oxygen pressure swing absorption units. The oxygen separated is also used as a fuel with natural gas for reforming. The carbon dioxide is separated in another PSA which can be used for the production of urea.