MASTER. Q703laB- Codf ENGINEERING DEVELOPMENT AND DEMONSTRATION OF DETOX'~WET OXIDATION FOR MIXED WASTE TREATMENT. Abstract DISCLAIMER

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1 '..A i. ', Codf Q73laB- ENGNEERNG DEVELOPMENT AND DEMONSTRATON OF DETOX'~WET OXDATON FOR MXED WASTE TREATMENT Patrik M. Dhooge, Sott D. Goldblatt, James E. Moslander, Donald T. Robertson, Terry W. Rogers, and Joseph A. Zigmond Delphi Researh, n., Albuquerque, NM. Abstrat SM DETOX, a atalyzed hemial oxidation proess, is under developmentfor treatment of hazardous and mixed wastes at Department of Energy sites. To support this effort, developmental engineering studies have been pegormed for aspets of the proess to help ensure safe and effetive operation. Subsale agitation studies have been pegormed to identi& a suitable mixing head and speed for the primary reation vessel agitator. Mehanismsfor feeding solid waste materials to the primary reation vessel have been investigated. Filtration to remove solidijied proess residue, and the use of variousjtltration aids, has been studied. Extended ompatibility studies on the materials of onstrution have been pegormed. Due to a hange to Roky Flats Environmental Tehnology Site (RFETS)for the mixed waste portion of the demonstration, types of wastes suitable and appropriatefor treatment at RFETS had to be hosen. A prototype unit has beenfabriated and will be demonstrated on hazardous and mixed wastes at Savannah River Site (SRS) and RFETS during 997 and The unit is in shakedown testing at present. Data validation and an engineering evaluation will be pegormed during the demonstration. DSCLAMER This report was prepared as an aount of work sponsored by an ageny of the United States Government. Neither the United States Government nor any ageny thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the auray, ompleteness, or usefulness of any information, apparatus, produt, or proess dislosed, or represents that its use would not infringe privately owned rights. Referene herein to any speifi ommerial produt, proess, or servie by trade name, trademark, manufaturer, or otherwise does not neessarily onstitute or imply its endorsement, reommendation, or favoring by the United States Government or any ageny thereof. The views and opinions of authors expressed herein do not neessarily state or reflet those of the United States Government or any ageny thereof. - -~ ~~ ~ Fax: ( delphi@highfiber.om MASTER

2 NTRODUCTON The DETOXSMproess uses oxidation by ferri iron in an aqueous solution to destroy organi ompounds and keep toxi metals in the ionized state in solution. Due to the relatively low operating temperature (A 2O.OC) of the proess, it does not produe the toxi organi by-produts and volatilized metals found in the outputs of high temperature proesses suh as inineration. The gaseous emissions from the proess are of low volume and easily ontrolled. The proess is tolerant of the water ontent of wastes, and an oproess aqueous and organi wastes. t is not at this point developed for appliation to soils or other high inorgani ontent wastes. Due to the advantages the proess provides in low emissions and ability to treat a variety of waste types, inluding wastes and remediates ontaining multiple hazardous omponents, the Department of Energy Offie of Siene and Tehnology has funded demonstration of the proess on low level mixed wastes through the ndustrial Assistane Program at Morgantown Energy Tehnology Center. The objet of the demonstration is to provide verifiable data that an be used to allow future permitting and use for mixed, hazardous, and low level waste treatment. ENGNEERNG STUDES Agitation One of the most vital engineering parameters for the proess is the effetiveness of agitation. The DETOXSMreation vessel needs to have a stirrer arrangement whih is not overly omplex, but whih will effetively mix a wide variety of solids and liquids with the DETOXSMproess solution as well as ensuring good gas dispersion in the solution. A literature and vendor survey was onduted to identify andidate agitators that would have the desired mixing apabilities. Ten andidate stirrer and baffling arrangements were tested for mixing effiieny. The andidates were evaluated for gas holdup, ability to disperse immisible liquids and solids in water, and power use. Of the stirrerbaffle arrangements tested, the one with the best overall mixing was hosen for the prototype unit. Evaluation parameters versus power use for some of the stirrerbaffle arrangements are shown in Figures 1 and 2. Plae Fig. 1 here. Plae Fig. 2 here. Power urves for the stirring arrangements indiate that 6-7 kw (8-9 HP) per 1. gal. of solution is suffiient for the reation vessel agitator. The three best andidate agitator arrangements were benh-tested in oxidation of a liquid and two solids. Two arrangements gave nearly the same rate of arbon dioxide prodution, but one was muh simpler in onept. Solids Feeding Many mixed and radioative wastes are in solid form. Feeding solids to a pressurized reation vessel is more diffiult than feeding liquids. Benh sale tests had used an airlok arrangement, but an airlok is 2

3 impratial for feeding large amounts of solids to a pressurized vessel. A mehanism needed to be identified that was rugged in its ability to handle solids, simple and reliable in its ability to feed the solids to a pressurized reation vessel, and did not allow esape of gases from the reation vessel during feeding operations. A mixture of shredded paper, plastis, and rubber was used as a surrogate solid feed. The proportions of these materials were as speified by Roky Flats Environmental Tehnology Site (RFETS) for solid ombustible waste. The solid materials were not pre-wetted, nor did they ontain any surrogate hazardous materials. The materials were shredded to simulate the ation of a standard ommerial shredder being used to redue partile size and homogenize the waste before it is fed to the proess. Maximum feed rate for the tests was 25. kg (dry weight, organi material)/hr. Six solids feed mehanisms were tested for their ability to reliably feed solids. All mehanisms were used to feed solids into a vessel pressurized to 7. kpa (11 psi). The mehanisms were evaluated for their ability to reliably feed the solids into the pressurized vessel at a rate of up to 25. kg (dry weight, organi material)ihr with no gaseous blow-by. The best solids feed arrangement was hosen based on the results from these studies. Filtration Wastes ontaining inert materials or whih produe solids when treated require a filtration system to remove these solids from the proess solution. n addition, the proess solution will periodially aumulate enough dissolved toxi metals or radionulides that it will be desirable to solidify it for stabilization and ultimate disposal. The solidified proess solution will need to be isolated by filtration as well. Literature and vendor soures were investigated to identify a desirable filtration system. The ideal system would have materials of onstrution ompatible with the proess solution, be apable of filtering mironsized partiles from the proess solution, deliver solids into a drum or other suitable ontainer without manual handling, be rinsable, and preferably be automated. Several andidate systems were identified, and the list was redued to one type based on antiipated performane and prie. Subsale filtration studies identified the filtration rate for a DETOXSMproess solution loaded with approximately lo.% fine ( p)partiulate. The rate at whih rinse solution passed through the resulting filter ake was also measured. A filter system for the demonstration unit was sized based on the antiipated amount of inert and produed solids and the measured filtratiodrinse rates. This system was sized for a waste that ontains or produes an inert solid equal to about 6.% by weight of the waste. Subsequent to the filter sizing, studies were onduted on the effets of soluble inorgani salts loading and filtration aids on the solids filtration rate for the proess solution through a hosen filter medium. Some results of these studies are shown in Figure 3. Plae Fig. 3 here. Materials Compatibility Previously onduted ompatibility testing showed very low orrosion rates for the demonstration unit s materials of onstrution under the onditions of the DETOXSMproess. n addition to the formal testing, 3

4 ... a benh sale reation vessel had been used for over 4.hours in the presene of DETOXSMsolution at operating temperatures with no visible signs of orrosion. However, it was known that the DETOXSMproess solution would aumulate a variety of dissolved inorgani materials, inluding sulfate, phosphate, fluoride, and metal ions, during waste treatment. There was onern that buildup of soluble inorganis in the proess solution ould ause orrosion that was not seen in the presene of the pure DETOXSMsolution. Therefore, further tests were onduted with DETOXSMsolution saturated with a variety of ontaminant ions. As in previous ompatibility tests, oupons of the materials of onstrution were weighed to the nearest.1 mg and plaed into glass-or fluoroarbon-lined, sealed test vessels in the presene of the DETOXSM solution. Typially the oupons were plaed so that roughly half the oupon was below the solution surfae and half was in the gas spae above the proess solution. The test vessels were heated to the operating temperature of the proess and maintained at that temperature for a period of time. Then, the vessels were ooled, unsealed, and the oupons visually inspeted and weighed. The orrosion rate for the materials of onstrution remained low in the inorgani salt-saturated DETOXSM solution. A typial orrosion rate urve is shown in Figure 4. After an initial period the surfae of this material apparently passivates, so that very little additional orrosion ours. The rate of orrosion even before passivation is low. Plae Fig. 4 here. WASTE SELECTON AT WETS The waste surrogate seletion for the portion of the demonstration at SRS was given in last year's paper (1). Due to a site hange from Weldon Spring Site Remedial Ation Projet (WSSRAP) to RFETS for the mixed waste treatment phase of the demonstration projet, the seletion of mixed wastes to be treated has been altered. The hange in waste types does not affet the validity of the demonstration, and may even make the results more appliable to other DOE sites. Waste types for the demonstration have been hosen based on a variety of fators. The wastes had to be suitable for treatment by the DETOXSMproess. The wastes had to be treatable under the regulatory environment of the site. The wastes had to be representativeof wastes in the DOE omplex. The wastes had to be available at the site. The types of wastes treated should, onsistent with a reasonable demonstration time and ost, demonstrate the versatility of the proess and generate a data base for appliation of the proess to as wide a range of waste as pratial. 4 -

5 Wastes that have been hosen for demonstration treatment at RFETS are oils, solvents, solid ombustibles, filter materials, ontaminated insulation, paints and paint sludges, solidified organis, PCB-ontaminated fluids, and exess hemials. Mostly surrogates will be tested at SRS, while all of the wastes to be treated at RFETS are mixed wastes ontaining low levels of uranium and /or plutonium. The variety of materials to be treated should establish a wide range of appliation for the proess, inluding materials that have high inorgani ontent, and PCB-ontaminated materials. At the same time, a signifiant volume of RFETS waste will be treated during the demonstration. DEMONSTRATON PROTOTYPE The demonstration prototype unit has an estimated throughput of 25. kg (dry weight, organi material)/hr. Throughput will be greater for wastes with signifiant water or inert solids ontent, sine these materials do not have to be oxidized. The prototype is a transportable modular design onsisting of two proess modules, an oil heatingkooling module, an oil hilling module, a motor ontrol enter, and a ontrovlaboratory trailer. A supply of oxygen gas is typially provided by vaporization from a ryogeni tank of liquid oxygen. Liquid or solid wastes an be treated in the prototype unit. Liquid wastes are introdued into the primary reation vessel with a diaphragm metering pump. Solid wastes are shredded, slurried in water, and pumped into the primary reation vessel. Produt gases are monitored for HC1 and total gaseous organi ompounds, and passed through an ativated arbon bed and HEPA filter before release. Produt water from the proess is ondensed, neutralized, sparged, and pumped into an effluent storage tank for testing before being sent to wastewater treatment or disposal. nert and produed solids an be filtered from the DETOXSMproess solution during waste treatment, and are automatially delivered into drums for stabilization and disposal. SHAKEDOWN TESTNG The demonstration prototype is undergoing shakedown testing at SRS s Multipurpose Pilot Plant Campus (formerly the TNX faility). Shakedown testing involves a funtional evaluation of the prototype, followed by separate trial oxidations of mineral oil and a mixture of ombustible solids. Shakedown testing will evaluate the funtionality and orretness of the prototype unit systems and operating proedures using non-toxi organi feed materials. The ontrol loops will be fine-tuned, and safety, sampling, and environmental ompliane proedures pratied to test their appropriatenessand give personnel experiene with the proedures. Operating parameters for the prototype will be adjusted to attempt to ahieve good destrution effiienies when surrogate waste treatment begins. The shakedown period will allow any obviously faulty omponents andor proedures to be identified and orreted before treatment of surrogate wastes begins, and will give the operating tehniians a period to familiarize themselves with all aspets of prototype operation. 5

6 .. L DATA VALDATON AND ENGNEERNG EVALUATON Experimental data from the demonstration, and in partiular analytial data on emissions from the prototype unit, will be validated by an independent third party to help ensure that the data has been olleted in a proper manner for aeptane by environmental regulators and potential users of the tehnology. The data validator will review the Demonstration Test Plan and the Sampling and Analysis Plan, and will prepare a Validation Plan for the demonstration. nput from the Primary Stakeholders and regulatory representatives will aid in developing a test sheme that generates appropriate and verifiable data to support subsequent appliation of the proess. The validator will audit the prototype operations, sample analysis, data management, and data interpretation to verify the results obtained. During the later stages of the demonstration, an engineering assessment of the DETOXSMtehnology will be onduted to determine the ost and appliability of the proess. A baseline ommerial design will be prepared, with ost and sensitivity analyses based on system and feed parameters. The engineering evaluation will use the determined destrution effiienies, throughputs, and emissions for the waste types treated in the demonstration, in addition to information on apital ost, maintenane ost, labor ost, utilities use, operating materials ost, and stream fator (i.e., the perentage of time the unit an expet to be operating) to determine unit sizes and osts for typial ommerial appliations. The baseline ommerial design will inorporate any needed improvements that have resulted from the demonstration testing, and proess improvements that may have ourred during the period of the demonstration. Sensitivity analysis will help identify the best operating regimens, and the waste types and volumes to target in ommerial appliation. ACKNOWLEDGMENTS We would like to thank EM-5, and in partiular Clyde Frank, Paul Hart, William Shutte, James Taylor, and Allison Johnson, for their support and assistane in making this projet possible. We would like to aknowledge the exellent assistane and support provided by METC and the CORs assigned to the projet, V.J. Kothari, James Westhusing, Keith Westhoff, and our urrent COR, William Huber. We would also like to aknowledge the help and assistane we have obtained from the DOE and M&O personnel at Savannah River Site and Roky Flats Environmental Tehnology Site, espeially Howard Pope, George Mishra, Beverly Skwarek, Steve Sheetz, Mark Fahada, David Boye, Frank Lustig, Gary Huffman, Linda Bateman, Jeff Petersell, Charles Brown, and Beth Fabrizio. This work is being performed under the review of the Department of Energy s Mixed Waste Fous Area. REFERENCES 1. S.D. GOLDBLATT, D.T. ROBERTSON, T.W. ROGERS, H. POPE, W. HUBER, and P.M. DHOOGE, Representative Waste Types, Estimated Emissions, Permitting ssues, and Operational Safety for Demonstration of DETOXSMWet Oxidation on Hazardous and Mixed Wastes, Proeedings of WM 96, Morton E. Waks, Tehnial Program Chairman, The University of Arizona, Tuson, Arizona. 6

7 Figure Power per Unit Volume (HP/1 gal.) Gas Holdup Volume versus Normalized Power for Candidate Agitator Systems 6

8 r &' 5: Suspension Height, % of Liquid Bath Height 1 p N V \ \ V ha h) V w w V L C t 9 W p ~ Q \ Y Q 1 \ C C O \

9 r 6. Total Preipitate Removed (YOof theoretial iron oxide weight) 1 CD w 1 1 % 8

10 Figure Time (hours) Coupon Weight versus Exposure Time for Prototype Material of Construt ion

11 DOE