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Scaling-up13C separation by infrared multiphoton dissociation of the CHClF2/Br2 system

Research paper by G. C. Chen, B. Wu, J. L. Liu, Y. Jing, M. X. Chu, L. L. Xue, P. H. Ma

Indexed on: 01 Jun '95Published on: 01 Jun '95Published in: Applied Physics B



Abstract

13C separation at a laboratory scaled-up level by the13C-selective InfraRed MultiPhoton Dissociation (IRMPD) of CHClF2 in the presence of Br2 has been investigated in a flow reactor. With a complete scaled-up system including a flow reactor, an industrially reliable TEA CO2 laser with longer pulse duration and a product-separation set-up for13C separation, it has been attempted to optimize the parameters suitable for large-scale production of the carbon isotope. The optimization of13C separation parameters, such as laser fluence, laser frequency and the partial pressure of CHClF2 and Br2 was tested under static conditions. By irradiation with longer pulses, a lower optimum pressure for a high13C-production rate was determined. Furthermore, the separation process was scaled in the flow system to examine the13C-production rates,13C atomic fractions in the CBr2F2 products and13C depletions in the CHClF2 reactants at different flow rates and laser repetition frequencies. The data obtained from the flow tests demonstrated a 40 mg/h production rate for CBr2F2 at 65%13C by using a 40 W (4 J, 10 Hz) laser beam focused with a lens of 120 cm focal length. If the reliable TEA CO2 laser is operated with 100 W (10 J, 10 Hz) output, the production rate of CBr2F2 for13C at 60% of 200 mg/h can be attained. The measurements of the spatial profile of the focused laser beam imply a 2 g/h production rate for the 60%13C product for an incident power of 200 W (20 J, 10 Hz).