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Title: Ammonia removal from oil shale process waters using tubular, microporous polytetrafluoroethene membranes. [Occidental burn No. 6, Geokinetics-9 and Paraho]

Conference ·
OSTI ID:5714681

Oil shale process waters can contain high concentrations (1 to 30 g/L) of dissolved ammonia/ammonium ion, most of which must be removed prior to discharge or codisposal. Nonosmotic dissolved-gas dialysis (NOGD), a membrane separation process that uses tubular, microporous hydrophobic polytetrafluoroethene (PTFE) membranes, is being evaluated as an alternative to conventional ammonia removal methods, such as steam stripping. Unlike most conventional methods, NOGD is more selective for ammonia, and it combines both removal and recovery of ammonia in a single unit process. The PTFE membrane serves as a gaseous barrier between two aqueous phases. Dissolved ammonia diffuses from the wastewater through the gaseous interface to an acidic absorption solution (dialysate), which serves to maintain the concentration gradient of ammonia gas across the membrane wall. This separation process has been described in a numeric model based on the diffusive transport of ammonia. For an ammonium hydroxide solution, correlation between the numeric model and experimental results was greater than 90% using mass-transfer coefficients as the basis of comparison; correlation between the model and experimental data for waters from three oil shale retorts (Occidental burn No. 6 (Oxy-6), Geokinetics-9, and Paraho) was poorer. On the basis of hydraulic residence times (HRT), the ammonia removals attained were 56% for Oxy-6 (0.92 min HRT), 55% for Geokinetics (0.87 min HRT), and 64% for Paraho (0.83 min HRT). These results from bench-scale experiments demonstrate the potential of NOGD as a rapid ammonia removal process. 22 refs., 5 figs., 2 tabs.

Research Organization:
Lawrence Berkeley Lab., CA (USA); California Univ., Richmond (USA). Sanitary Engineering and Environmental Health Research Lab.
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5714681
Report Number(s):
LBL-20758; CONF-8604172-4; ON: DE86013186
Resource Relation:
Conference: 19. annual oil shale symposium, Golden, CO, USA, 21 Apr 1986
Country of Publication:
United States
Language:
English