Ammonia Essay

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ENVIRONMENTAL, HEALTH, AND SAFETY ISSUES 1. INTRODUCTION Ammonia is a compound of nitrogen and hydrogen with the formula of NH3. It is colorless gas and has a pungent odor. Ammonia is generally manufactured from natural gas using the steam reforming process. Ammonia has dozens of uses such as in fertilization, pharmaceuticals, and also in petrochemicals. Although it is in wide used, ammonia is both caustic and hazardous. 2. ENVIRONMENTAL ISSUES During the normal operation of a reforming plant, only the NOx and CO2 emissions have to be considered. In partial oxidation plants with oil-fired auxiliary boilers the reduction of SO2 emissions can be achieved by using low sulphur fuel oil. From steam reforming plants with a fired primary reformer, emissions into air come from the various sources such as flue-gas from the primary reformer, vent gas from removal of carbon dioxide, breathing gas from oil buffers (seals / compressor) and also from non-continuous emissions (venting and flaring) (Ave, Evan Nieuwenhuyse, 2000). For pollution related to water, it may occur due to process condensates or due to the scrubbing of waste gases containing ammonia under normal operation. Process condensate is found in the condensation section prior to the carbon dioxide removal, of the order of one meter cube per ton of ammonia produced. Without treatment this condensate can contain up to 1kg of ammonia and 1kg methanol per m3. More than 95% of the dissolved gases can be recovered by stripping with process steam and are recycled to the process. The stripped condensate can be re-used as boiler feed water make-up after treatment by ion exchange. Usually the ammonia absorbed from purge and flash gases is recovered in a closed loop so that no aqueous ammonia emissions occur. Emissions into water from the production plant during normal operation can thus be fully avoided. Besides
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