Preventing atmospheric ammonia emissions: A generator/regulator solution

摘要

During most of the 60 years that TVA has been in existence, the research center at Muscle Shoals, Alabama, NERC, was charged with supporting the regional and national agribusiness industry. One aspect of this support was strong emphasis on fertilizer process and product development. One such product developed at the center was a liquid fertilizer with a grade of 10-34-0 (N-P(sub 2)O(sub 5)-K(sub 2)O). The process was profitable and easy to operate, the product was well accepted by both farmers and dealers, and 10-34-0 became the premium phosphate fertilizer used in the United States. Approximately 120 to 130 of these type units have been constructed and operated in the United States in the last 20 years. During that time, the process design has remained essentially unchanged. The direct contact between the hot fertilizer product and the air results in some free ammonia being stripped from the product and emitted from the top of the cooling tower. At the time most of the plants were constructed, there was little concern over these losses because (1) there were very few regulations dealing with ammonia and (2) most of the plants were originally built and operated in rural areas away from population centers and emissions that occurred went essentially unnoticed. However, as a result of this study, process changes that can reduce ammonia, as well as fluoride and particulate emissions have been identified and mad available to generators. In addition a potential process for the total elimination of emissions has been developed and made available on a trial basis.