Fig. 3-3 Schematic drawing of the pilot plant for electron beam flue gas treatment, installed at Kaweczyn thermoelectric power station (Poland)

Fig. 3-4 Reaction of sulfur/nitrogen oxides with ammonia under the irradiation of electron beams Sulfur/nitrogen oxides are shown to be converted into ammonium sulfate/nitrate immediately after exposure to the electron beams.

Flue gases exhausted from thermoelectric power plants and municipal waste incinerators contain environmental pollutants such as sulfur/nitrogen oxides, which cause acid rain. When the flue gas is irradiated by electron beams (EB) in the presence of ammonia gas, the sulfur and nitrogen oxides are converted into ammonium sulfate and nitrate respectively, which are useful as agricultural fertilizers. This EB technique for flue gas treatment has been studied in Japan since the early 1970's. Now engineering studies and feasibility studies have been performed using a pilot-scale plant, under a cooperative agreement between JAERI and a consortium of private engineering and electric power station companies. In an international research collaboration supported by the International Atomic Energy Agency (IAEA), JAERI and Institute of Nuclear Chemistry and Technology, Poland (INCT) have further developed the EB treatment of flue gases exhausted from coal-fired power stations. For the international collaboration, a pilot plant equipped with 2 electron accelerators at the Kaweczyn Electric Power Station in Poland was used, and the following research items were studied: 1. Multi-stage irradiation and its effect on process efficiency 2. Effective collection of by-products, (NH4)2SO4 and NH4NO3 3. Optimization of the process control of the plant. Based on the results obtained through this cooperation, an industrial-scale demonstration plant with a treatment capacity of 2.7 x 105 Nm3/h (corresponding to the amount of flue gas an hour, exhausted from a 5.6 x 104 kW coal-fired electric power station) is now being installed at Pomorzany Thermoelectric Power Station in Poland, under the support of the IAEA and the Japanese government. It will begin operation in 1999.

Reference O. Tokunaga et al., Electron Beam Flue Gas Treatment: Research Cooperation among JAERI, IAEA and INCT, JAERI-Research 96-053 (1996).

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