Photons and electrons with energies above the ionization potential of most atoms can be used to facilitate chemical reactions not otherwise possible thermochemically or under more preferable process conditions. These ionizing radiations have a wide range of potential chemical process applications and can be produced using several different commercially available sources. An analysis and comparison of the economics of using sources of ultraviolet photons, high-energy electrons, gamma rays, and x-rays in a chemical conversion process is presented. Capital cost estimates make use of quotations from commercial equipment vendors and literature values where available. The question of, “Which radiation source is the lowest cost means of delivering equivalent ionizing radiation energy to a chemical reactor system?” is addressed. Based on commercial sources and isotopes presently available, in many processes where the penetration depth is sufficient, the overall production costs for equivalent products are lowest for electron-beam based systems followed, in order, by ultraviolet, gamma rays from Co-60, and X-ray sources. The source capital costs varied from $15 to $150 per watt of radiation power delivered to the reactor system, with the operating costs varying from $26 to $161 per watt-year of energy delivered (820 to 5100 $/GJ). For specific chemical products, the efficiency of use of the radiation source depends upon the conversion efficiency of the deposited radiation which can depend on the type and energy of the radiation. In process applications where large volume, high pressure, chemical reactors are required, gamma radiation has potential design advantages provided commercial gamma sources of lower cost than 60 Co become available.
Chemistry and Pharmacology
Process Engineering, Biotechnology, Nutrition Technology