Production of Fertilizer in a Multipurpose Atomic Power Reactor Complex for Distillation of Sea Water: A Survey (1963)

< 4 = e to determine the feasibility of producing large amounts of nitrogen, phosphate, and potassium fertilizers with the cheap power produced from a large atomic reactor. The optimum combination was a multipurpose plant to produce fresh water from sea water by distillation and fertilizer from the air, sea, and phosphate rock. No other raw materials are required and only the three principal fertilizers containing nitrogen, phosphorus, and potassium are produced. Large amounts of byproducts, requiring shipment and sale, are not produced. The arc process is used for nitrogen fixation from air to produce nitric acid and fresh water is electrolyzed to produce hydrogen for nitrogen fixation from air as ammonia. Ammonium nitrate can be formed as the final product. Alternatively, nitric acid could be produced by oxidation of ammonia instead of the arc process, if cheaper. Dicalcium phosphate or triple superphosphates are produced by nitric acid leaching of phosphate rock or by treating phosphate rock in an electric furnace with coke and silica. In the furnace process, coke must be shipped in as a raw material but silica would be available at oceanside locations. Potassium is recovered from sea water by precipitation of potassium dipicrylamine. Acidification of the precipitate with nitric acid produces potassium nitrate and the dipicrylamine is freed for reuse. Potassium can also be precipitated as magnesium calcium potassium phosphate but additional caustic must be shipped in to neutralize the phosphoric acid. The effect of reducing power costs per kwh from 8 to 10 mills for private industry or from 4 mill/kwh for TVA to 1 mill at a large multipurpose reactor station were estimated. The use of electrical power to replace natural gas as a process heat source was also assumed. Reductions in ammonia or dicalcium phosphate prices of less than 5% were predicted since these processes use large amounts of natural gas as process heat which has a cost equivalent to 1 mill/kwh. Conversely, however, the use of 1 mill/kwh electrical power would permit production of economical fertilizer at locations where natural gas is unavailable or must be conserved. The reduction of power cost from 4 to 1 mill/kwh decreased the cost of triple superphosphate produced in electric furnaces by 13%. This cost was estimated to be 16% cheaper than for superphosphate produced by the conventional sulfuric acid process at a Florida location. The cost of producing ammonium nitrate, a very desirable solid form of fertilizer suitable for long distance shipment, was estimated. The cost, by the electrolysis of water (at 1 mill/kwh) to produce hydrogen, fixation of nitrogen and hydrogen as ammonia, and oxidation of ammonia to nitric acid route, was estimated to be about 50% higher than the present method which uses natural gas as a raw material to produce hydrogen. Since these steps are modern engineering techniques, little further reduction in cost is expected. Hence, the production of nitric acid by arc fixation of air is the key item which could potentially reduce costs significantly for the whole complex but one which could not be estimated with accuracy without a detailed cost estimate and design survey. At 1 mill/kwh, the power cost alone for arc fixation of nitrogen is 029/ lb N. Thus are fixation nitrogen might be competitive with ammonium nitrate but not with ammonia which sell for 104 and 056/lb N, respectively. Since only 3% of the total energy of the arc process is used for nitrogen fixation, the wasted heat could be used to distill sea water and thus reduce the cost of nitrogen fixation. However, the reduction in cost of nitrogen fixation may be small since the energy is degraded before return to the distillation system. For example, if 30% of the heat is recovered as high temperature steam (worth 41 mill/kwhh or 120 mill/10/sup 6/ Btu) and 20% is useful as process heat (worth 034 mill/ kwh/sub h/ or 10 mill/10/sup 6/ Btu) the reduction in total cost of power for nitrogen fixation (using 1 mill/kwh/sub e/) is 13%. In