Computer aided study of coal utilization in the United States ammonia industry

A study is made to develop possible alternatives to replace expensive natural gas for manufacturing ammonia. The alternative energy source coal, has been considered to replace natural gas as feedstock as well as fuel for the primary reformer in a conventional steam reforming process for the production of ammonia. Natural gas feedstock is replaced by generating synthesis gas using a coal-fed Texaco gasifier. A Coal fired Atmospheric Fluidized Bed Combustor (AFBC) reformer and Medium Btu Gas (MBG) fuel are considered as alternative arrangements.

The Advanced System for Process Engineering (ASPEN) computer simulation is utilized to perform mass and energy balances for different process flow-schemes. The economics of ammonia production with various process alternatives is developed with the help of CASHFLOW computer program for discounted cash flow.

The future year production costs of ammonia with alternative arrangements were compared with the costs for conventional process to find out the break even point in time. The AFBC reformer arrangement was found to be economically attractive whereas MBG fuel for the reformer was observed to be too expensive. Coal as a feedstock for ammonia production is expected to be economical during the early years of next decade, but not in immediate future.