Sorbents for the removal of airborne heavy metals from the incineration of waste lubricating oils

Sorbents for the removal of airborne heavy metals from the incineration of waste lubricating oils

ABSTRACTS rated priority pollutants. Toward that end, the PIs have previously established the following data base of such technologies: 1) sodium per...

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rated priority pollutants. Toward that end, the PIs have previously established the following data base of such technologies: 1) sodium perborate mediated oxidation applicable to a range of model compounds and to some priority pollutants; 2) the efficacy of mixed oxidation systems; 3) the general utility of appropriate ruthenium species as the catalytic contributor in mixed oxidation systems and; 4) the potential of sodium hypochlorite (household bleach) as the safe, cheap and efficient co-oxidant in a practical mixed oxidation system. The focus of the work in the current proposal is to define, develop and optimize a new oxidative degradation technology based on a sodium hypochlorite/ruthenium oxide mixed oxidation system. The work will include the following studies: 1) in-depth study with styrene to optimize the reaction conditions; 2) reaction survey of a range of structural class model compounds under the optimized conditions; 3) reaction survey of several representative unsaturated priority pollutants under the optimized conditions and; 4) investigation of the feasibility of using an inert-supported ruthenium species in the process. The extent of oxidative conversion determined under the established optiumum reaction conditions will allow an assessment of the practicality of applying a sodium hypochlorite/ruthenium mixed oxidation system to a large-scale process for decomposing unsaturated priority pollutants. SORBENTS FOR THE REMOVAL OF AIRBORNE HEAVY METALS FROM THE INCINERATION OF WASTE LUBRICATING OILS M a t t h e w J. H a l l Mechanical Engineering and Center for Energy Studies, University of Texas at Austin, 10100 Burnett Road, Austin, TX 78758, U.S.A.

The objective of the on-going research is to study the effectiveness of inorganic sorbents to adsorb and remove heavy metal emissions from the combustion by-products of incinerated waste lubricating oils that have a high contaminant level of metals. The artificially introduced sorbents (typically clays or alumina) could be removed from the effluent stream of a waste incinerator using conventional baghouse collection techniques. In this project a 20 kW turbulent flow reactor is being used to achieve the temperature and residence times typical of a liquid waste incinerator. Simulated metal-containing lubricating oils are atomized


and burned in the flow reactor. Downstream of the reaction zone, gas samples containing the sorbent particles are drawn into a particle impactor which collects the airborne particles and condensed phase metal aerosols, separating them into eight size ranges from 04 m to greater than 10 m. These samples are then analyzed for their metals content to determine the scavenging efficiency of the sorbents. Barium and lead are the targeted metals. Operating conditions are to be varied to determine the effect of sorbent and the sorbent loading, and the influence that chlorine has on the performance of the adsorption process. We received funding in June and in September 1993 to begin work on the first year of this project. Despite the short time that has passed, considerable progress has been made. The oil injection system has been built, and preliminary measurements have been carried out in the flow reactor using a premixed propane flame to create the incinerator-like conditions. The metal compounds have been injected separately in a solution. The only sorbent/metal combination we have investigated so far is kaolinite and lead. We have successfully collected the particles and analyzed them for both the amount of sorbent in each particle size range and the lead content. We have found that under the conditions we have examined so far, the kaolinite successfully adsorbs a large quantity of lead with the smaller particles of kaolinite adsorbing more, for their weight, than the larger particles. We hope to continue this work examining barium and the effectiveness of other sorbents. W A S T E M I N I M I Z A T I O N BY P R O C E S S MODIFICATION Jack R. Hopper and Carl L. Yaws Chemical Engineering, Lamar University, P.O. Box 10053, Beaumont, Texas 77710, U.S.A.

This project involves a continuation of research by Hopper and Yaws to develop examples of waste minimization by process modifications. These examples can be used as guidelines by process and environmental engineers in developing strategies for pollution prevention. In the first phase, waste minimization by process modification was investigated for the production of allyl chloride. In the second phase, analysis of waste minimization by process modification was initiated for the production of acrylonitrile. Acryloni-