Air Abatement Equipment

Emissions from the prilling and granulation sections of AN and CAN plants can be treated by a range of abatement equipment. Particulate material from some granulation plants is relatively coarse in particle size, whereas the prill tower emissions contain very fine particles. Candle filters are normally required for a prill tower emission. They can abate particulate emissions down to 15 mg/m3 of air. For coarser material dry devices such as bag filters or dry cyclones are used. Particulate emissions can be of higher concentration, perhaps up to 30 to 50 mg/m3, but the recovered material is a solid that can more readily be recycled to the process. 

Production of fertilizer grade AN is concentrated mainly in Europe and North America. Apparent demand in the United States was 18% below the 1998 level of 10 billion tons. This was mainly due to weakness in the fertilizer sector. US production of urea-ammonium nitrate (UAN) solutions also dropped significantly (from 3.8 million tons in 1998 to 2.9 million tons in 2001) from 1999 to 2001. In 2001 US ammonium nitrate capacity remains well in excess of domestic requirements as the industry operated at less than 70% of nameplate US capacity. Table 10.1 summarizes US supply and demand240. 

Demand fluctuations are difficult to predict because of the variety of factors that influence fertilizer demand and farm economics in any given year. Demand from the explosives industry has been more stable. This is because demand from the coal mining industry accounts for two-thirds of total US explosives consumption. And coal production has grown from 1.06 billion tons per year in 

1996 to 1.12 billion tons in 2001. However AN demand for fertilizers is likely to trend up very slowly. AN demand for explosives is expected to grow modestly240. 

As a large volume commodity chemical, AN prices fluctuate with changes in the supply/demand balance and with raw material costs. The list price has been 150 per ton since 1995 and is expected to stay at that level through 2004. Between 1995 and 2001 the average sales price has varied from a low of 128 per ton in 2000 to a high of 143 per ton in 2001240. 

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