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Task 2.8 - Mercury Speciation and Capture in Scubber Solutions

Description: U.S. Environmental Protection Agency (EPA) investigation into health risks associated with mercury emissions from utility steam generators, municipal waste combustion units, and other sources was mandated by the Clean Air Act Amendments (CAAA) of 1990. In anticipation of mercury emission regulation, attention has been focused on quantification of mercury emissions, which require verifiable sampling and analytical techniques. Several sampling and analytical methods are currently under the final stages of development as well as a variety of emission control methods. In particular, wet scrubber systems designed for S2 control in coal-fired utilities have been targeted for mercury control. Conventional wet-scrubbers remove mercury in a variety of soluble oxidized forms. Oxidized mercury is highly water-soluble and can be removed by scrubber slurry, theoretically limited only by gas-film mass transfer. However, since some oxidized mercury forms such as HgClz are borh soluble and volatile, the final fate of mercury trapped in scrubber solutions is unclear. Elemental mercury is not water-soluble, remaining in the vapor state at temperatures through pollution control devices and exiting the stack into the environment. However, notable exceptions to this rule exist. Depending on the type of mercury-sampling method used, an increase ofs 10% in elemental mercury concentrations across wet scrubbers has been metiured but is yet unconllrmed. Also, significant amounts of elemental mercury (metallic form) have been removed during wet scrubber maintenance. In addition, questions concerning 1) the initial speciation between oxidized and elemental forms of mercury in flue gas from coal- fired boilers and 2) the effects of scrubber slurry composition and pH on the mercury species have been raised.
Date: August 1, 1997
Creator: Ness, Sumitra R.
Partner: UNT Libraries Government Documents Department

PILOT-AND FULL-SCALE DEMONSTRATION OF ADVANCED MERCURY CONTROL TECHNOLOGIES FOR LIGNITE-FIRED POWER PLANTS

Description: North Dakota lignite-fired power plants have shown a limited ability to control mercury emissions in currently installed electrostatic precipitators (ESPs), dry scrubbers, and wet scrubbers (1). This low level of control can be attributed to the high proportions of Hg{sup 0} present in the flue gas. Speciation of Hg in flue gases analyzed as part of the U.S. Environmental Protection Agency (EPA) information collection request (ICR) for Hg data showed that Hg{sup 0} ranged from 56% to 96% and oxidized mercury ranged from 4% to 44%. The Hg emitted from power plants firing North Dakota lignites ranged from 45% to 91% of the total Hg, with the emitted Hg being greater than 85% elemental. The higher levels of oxidized mercury were only found in a fluidized-bed combustion system. Typically, the form of Hg in the pulverized and cyclone-fired units was dominated by Hg{sup 0} at greater than 85%, and the average amount of Hg{sup 0} emitted from North Dakota power plants was 6.7 lb/TBtu (1, 2). The overall objective of this Energy & Environmental Research Center (EERC) project is to develop and evaluate advanced and innovative concepts for controlling Hg emissions from North Dakota lignite-fired power plants by 50%-90% at costs of one-half to three-fourths of current estimated costs. The specific objectives are focused on determining the feasibility of the following technologies: Hg oxidation for increased Hg capture in wet and dry scrubbers, incorporation of additives and technologies that enhance Hg sorbent effectiveness in ESPs and baghouses, the use of amended silicates in lignite-derived flue gases for Hg capture, and the use of Hg adsorbents within a baghouse. The scientific approach to solving the problems associated with controlling Hg emissions from lignite-fired power plants involves conducting testing of the following processes and technologies that have shown promise on a bench, ...
Date: February 1, 2004
Creator: Benson, Steven A.; Crocker, Charlene R.; Galbreath, Kevin C.; Gunderson, Jay R.; Holmes, Mike J.; Laumb, Jason D. et al.
Partner: UNT Libraries Government Documents Department

CO (Carbon Monoxide Mixing Ratio System) Handbook

Description: The main function of the CO instrument is to provide continuous accurate measurements of carbon monoxide mixing ratio at the ARM SGP Central Facility (CF) 60-meter tower (36.607 °N, 97.489 °W, 314 meters above sea level). The essential feature of the control and data acquisition system is to record signals from a Thermo Electron 48C and periodically calibrate out zero and span drifts in the instrument using the combination of a CO scrubber and two concentrations of span gas (100 and 300 ppb CO in air). The system was deployed on May 25, 2005.
Date: February 23, 2011
Creator: Biraud, S
Partner: UNT Libraries Government Documents Department

LONG-TERM DEMONSTRATION OF SORBENT ENHANCEMENT ADDITIVE TECHNOLOGY FOR MERCURY CONTROL

Description: Long-term demonstration tests of advanced sorbent enhancement additive (SEA) technologies have been completed at five coal-fired power plants. The targeted removal rate was 90% from baseline conditions at all five stations. The plants included Hawthorn Unit 5, Mill Creek Unit 4, San Miguel Unit 1, Centralia Unit 2, and Hoot Lake Unit 2. The materials tested included powdered activated carbon, treated carbon, scrubber additives, and SEAs. In only one case (San Miguel) was >90% removal not attainable. The reemission of mercury from the scrubber at this facility prevented >90% capture.
Date: May 27, 2011
Creator: Laumb, Jason D.; Laudal, Dennis L.; Dunham, Grant E.; Kay, John P.; Martin, Christopher L.; Thompson, Jeffrey S. et al.
Partner: UNT Libraries Government Documents Department

Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Description: The overall goal of this project was to evaluate the ability of novel adsorbent/reactants to remove specific toxic target chemicals from ash and scrubber pond effluents while producing stable residuals for ultimate disposal. The target chemicals studied were arsenic (As(III) and As(V)), mercury (Hg(II)) and selenium (Se(IV) and Se(VI)). The adsorbent/reactants that were evaluated are iron sulfide (FeS) and pyrite (FeS{sub 2}). Procedures for measuring concentrations of target compounds and characterizing the surfaces of adsorbent-reactants were developed. Effects of contact time, pH (7, 8, 9, 10) and sulfate concentration (0, 1, 10 mM) on removal of all target compounds on both adsorbent-reactants were determined. Stability tests were conducted to evaluate the extent to which target compounds were released from the adsorbent-reactants when pH changed. Surface characterization was conducted with x-ray photoelectron spectroscopy (XPS) to identify reactions occurring on the surface between the target compounds and surface iron and sulfur. Results indicated that target compounds could be removed by FeS{sub 2} and FeS and that removal was affected by time, pH and surface reactions. Stability of residuals was generally good and appeared to be affected by the extent of surface reactions. Synthesized pyrite and mackinawite appear to have the required characteristics for removing the target compounds from wastewaters from ash ponds and scrubber ponds and producing stable residuals.
Date: January 31, 2010
Creator: Batchelor, Bill; Han, Dong Suk & Kim, Eun Jung
Partner: UNT Libraries Government Documents Department

Designing a scrubber for maintenance

Description: Under Round 4 of the U.S. Department of Energy`s (DOE) Clean Coal Technology program, New York State Electric & Gas Corporation (NYSEG), in partnership with Saarberg-Holter-Umwelttechnik (SHU), Consolidation Coal Company and Stebbins Engineering and Manufacturing Company, has retrofitted a formic acid enhanced forced oxidation wet limestone scrubber on Units I and 2 at the Milliken Steam Electric Station. Units I and 2 are 1950s vintage Combustion Engineering tangentially fired pulverized coal units, which are rated at nominal 150 MW each and operate in balanced draft mode. The Flue Gas Desulfurization (FGD) system for Unit 2 was placed into operation in January 1995 and the Unit I system in June 1995. The project incorporates several unique aspects: low pH operation; a ceramic tile-lined cocurrent/countercurrent, split module absorber; a wet stack supported on the roof of the FGD building; and closed loop, zero liquid discharge operation that produces commercial grade gypsum and calcium chloride brine. The project objectives include 98% SO{sub 2} removal efficiency while burning high sulfur coal, the production of marketable byproducts to minimize solid waste disposal, zero wastewater discharge, space-saving design, and minimization of maintenance requirements of a wet scrubber. The paper provides a brief overview of the project scrubber design relating to maintenance considerations. A discussion of the early results of the maintenance history is also provided. Repair techniques that have been developed and tested for ceramic tile lined modules are included. 1 fig.
Date: December 1, 1996
Creator: Mahlmeister, M.E.; Baron, E.S. & Watts, J.
Partner: UNT Libraries Government Documents Department

Ammonia scrubber testing during IDMS SRAT and SME processing. Revision 1

Description: This report summarizes results of the Integrated DWPF (Defense Waste Processing Facility) Melter System (IDMS) ammonia scrubber testing during the PX-7 run (the 7th IDMS run with a Purex type sludge). Operation of the ammonia scrubber during IDMS Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processing has been completed. The ammonia scrubber was successful in removing ammonia from the vapor stream to achieve NH3 concentrations far below the 10 ppM vapor exist design basis during SRAT processing. However, during SME processing, vapor NH3 concentrations as high as 450 ppM were measured exiting the scrubber. Problems during the SRAT and SME testing were vapor bypassing the scrubber and inefficient scrubbing of the ammonia at the end of the SME cycle (50% removal efficiency; 99.9% is design basis efficiency).
Date: April 28, 1995
Creator: Lambert, D.P.
Partner: UNT Libraries Government Documents Department

Zinc Bromide Combustion: Implications for the Consolidated Incinerator Facility

Description: In the nuclear industry, zinc bromide (ZnBr2) is used for radiation shielding. At Savannah River Site (SRS) zinc bromide solution, in appropriate configurations and housings, was used mainly for shielding in viewing windows in nuclear reactor and separation areas. Waste stream feeds that will be incinerated at the CIF will occasionally include zinc bromide solution/gel matrices.The CIF air pollution systems control uses a water-quench and steam atomizer scrubber that collects salts, ash and trace metals in the liquid phase. Water is re-circulated in the quench unit until a predetermined amount of suspended solids or dissolved salts are present. After reaching the threshold limit, "dirty liquid", also called "blowdown", is pumped to a storage tank in preparation for treatment and disposal. The air pollution control system is coupled to a HEPA pre-filter/filter unit, which removes particulate matter from the flue gas stream (1).The objective of this report is to review existing literature data on the stability of zinc bromide (ZnBr2) at CIF operating temperatures (>870 degrees C (1600 degrees F) and determine what the combustion products are in the presence of excess air. The partitioning of the combustion products among the quencher/scrubber solution, bottom ash and stack will also be evaluated. In this report, side reactions between zinc bromide and its combustion products with fuel oil were not taken into consideration.
Date: December 16, 1998
Creator: Oji, L.N.
Partner: UNT Libraries Government Documents Department

Cylinder supplied ammonia scrubber testing in IDMS

Description: This report summarizes the results of the off-line testing the Integrated DWPF Melter System (IDMS) ammonia scrubbers using ammonia supplied from cylinders. Three additional tests with ammonia are planned to verify the data collected during off-line testing. Operation of the ammonia scrubber during IDMS SRAT and SME processing will be completed during the next IDMS run. The Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) scrubbers were successful in removing ammonia from the vapor stream to achieve ammonia vapor concentrations far below the 10 ppM vapor exit design basis. In most of the tests, the ammonia concentration in the vapor exit was lower than the detection limit of the analyzers so results are generally reported as <0.05 parts per million (ppM). During SRAT scrubber testing, the ammonia concentration was no higher than 2 ppM and during SME testing the ammonia concentration was no higher than 0.05 m.
Date: August 31, 1994
Creator: Lambert, D.P.
Partner: UNT Libraries Government Documents Department

Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash

Description: This quarterly report covers the period from October 1st, 2003 through December 31st, 2003. It covers: technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period.
Date: January 1, 2004
Creator: Scandrol, Roy
Partner: UNT Libraries Government Documents Department

Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash

Description: This quarterly report covers the period from April 1st, 2003 through June 30th, 2003. It covers; technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period.
Date: July 1, 2003
Creator: Scandrol, Roy
Partner: UNT Libraries Government Documents Department

MERCURY AND LEAD SAMPLING AT MINNESOTA POWER'S BOSWELL ENERGY CENTER

Description: At the request of the Minnesota Power, Inc., the Energy & Environmental Research Center (EERC) sampled for lead at the stack (or duct directly leading to the stack) for three units at the Boswell Energy Center. All sampling was done in triplicate using U.S. Environmental Protection Agency (EPA) Method 12, with sampling procedures following EPA Methods 1 through 4. During the test program, lead sampling was done using EPA Method 12 in the duct at the outlet of the baghouse serving Unit 2 and the duct at the outlet of the wet particulate scrubber serving Unit 3. For Unit 4, lead sampling was done at the stack. The specific objective for the project was to determine the concentration of lead in the flue gas being emitted into the atmosphere from the Boswell Energy Center. The test program was performed during the period of May 8 through 11, 2000. This report presents the test data, sample calculations, and results, and a discussion of the lead sampling performed at the Boswell Energy Center. The detailed test data and test results, raw test data, process data, laboratory reports, and equipment calibration records are provided in Appendices A, B, and C.
Date: August 1, 2000
Creator: Laudal, Dennis L.
Partner: UNT Libraries Government Documents Department

Commercial Demonstration of the Manufactured Aggregate Processing Technology Utilizing Spray Dryer Ash

Description: This quarterly report covers the period from April 1, 2005 through June 30, 2005. It covers: technical development, permitting status, engineering status, construction status, operations summary and marketing support activities for this period.
Date: August 5, 2005
Creator: Scandrol, Roy O.
Partner: UNT Libraries Government Documents Department

HYDROFLUORIC ACID SCRUBBER SYSTEMS

Description: Each year over a million gallons of water are used to scrub hydrogen fluoride (HP) vapors from waste off-gas streams. Use of other potential scrubber solutions such as potassium hydroxide (KOH), aluminum nitrate nonahydrate (ANN), and monobasic aluminum nitrate (monoban) would result in significant volume reductions. A laboratory study was initiated to (1) demonstrate the effectiveness of these scrubber solutions to sorb HF, (2) determine if unexpected reactions occurred at flowsheet conditions, and (3) determine the consequences of deviation from flowsheet conditions. Caustic or aluminum scrubber solutions remove hydrogen fluoride from off-gas streams. Solids which appear with aluminum could be avoided by heating the scrubber solution.
Date: May 18, 2011
Creator: JV, PANESKO & HD, MERRITT
Partner: UNT Libraries Government Documents Department

The Homogeneous Forcing of Mercury Oxidation to Provide Low-Cost Capture

Description: Oxidized mercury formed in combustors (e.g., HgCl{sub 2}) is much more easily captured in existing pollution control equipment (e.g., wet scrubbers for SO{sub 2}) than elemental mercury. This is principally due to the high solubility of the oxidized form in water. Work over the last several years in our laboratory and elsewhere has identified the general outlines of the homogeneous chemistry of oxidation. The goal of the work reported here is to make use of this knowledge of the oxidation mechanism to devise simple and inexpensive ways to promote the oxidation. The hypothesis is that simple fuels such as hydrogen or CO can promote oxidation via the free radicals they generate during their decomposition. These free radicals then promote the formation of Cl from HCl via reactions such as OH+HCl {yields} H{sub 2}O+Cl. The Cl (and Cl{sub 2} derived from Cl recombination) are considered the principal oxidizing species. In our studies, mercury vapor is exposed to HCl under isothermal conditions in a gas containing N{sub 2}, O{sub 2}, and H{sub 2}O. The experiments systematically explore the influence of reaction temperature, HCl concentration, and H{sub 2}O concentration. These baseline conditions are then perturbed by the addition of varying amounts of H{sub 2}, CO, and H{sub 2}/CO added jointly. The following report presents the results of a literature review associated with the dissertation of the student supported by the program. This outlines the state-of-the-art in mercury behavior. It then describes the experimental facilities and the results of tests involving the promotion of the oxidation reaction by H{sub 2}, CO, and H{sub 2}/CO combinations. These results indicate a substantial enhancement of oxidation under isothermal conditions at 900-1000 K, while the additives inhibit oxidation at 1200 K. The next step is to determine whether the existing chemical kinetic models of mercury oxidation are capable ...
Date: April 1, 2006
Creator: Kramlich, John C. & Castiglone, Linda
Partner: UNT Libraries Government Documents Department

A Feasibility Study for Recycling Used Automotive Oil Filters In A Blast Furnace

Description: This feasibility study has indicated that of the approximately 120,000 tons of steel available to be recycled from used oil filters (UOF's), a maximum blast furnace charge of 2% of the burden may be anticipated for short term use of a few months. The oil contained in the most readily processed UOF's being properly hot drained and crushed is approximately 12% to 14% by weight. This oil will be pyrolized at a rate of 98% resulting in additional fuel gas of 68% and a condensable hydrocarbon fraction of 30%, with the remaining 2% resulting as carbon being added into the burden. Based upon the writer's collected information and assessment, there appears to be no operational problems relating to the recycling of UOF's to the blast furnace. One steel plant in the US has been routinely charging UOF's at about 100 tons to 200 tons per month for many years. Extensive analysis and calculations appear to indicate no toxic consideration as a result of the pyrolysis of the small contained oil ( in the 'prepared' UOFs) within the blast furnace. However, a hydrocarbon condensate in the ''gasoline'' fraction will condense in the blast furnace scrubber water and may require additional processing the water treatment system to remove benzene and toluene from the condensate. Used oil filters represent an additional source of high quality iron units that may be effectively added to the charge of a blast furnace for beneficial value to the operator and to the removal of this resource from landfills.
Date: January 21, 2002
Creator: Smailer, Ralph M.; Dressel, Gregory L. & Hill, Jennifer Hsu
Partner: UNT Libraries Government Documents Department

Analysis of cascade impactor and EPA method 29 data from the americium/curium pilot melter system

Description: The offgas system of the Am/Cm pilot melter at TNX was characterized by measuring the particulate evolution using a cascade impactor and EPA Method 29. This sampling work was performed by John Harden of the Clemson Environmental Technologies Laboratory, under SCUREF Task SC0056. Elemental analyses were performed by the SRTC Mobile Laboratory.Operation of the Am/Cm melter with B2000 frit has resulted in deposition of PbO and boron compounds in the offgas system that has contributed to pluggage of the High Efficiency Mist Eliminator (HEME). Sampling of the offgas system was performed to quantify the amount of particulate in the offgas system under several sets of conditions. Particulate concentration and particle size distribution were measured just downstream of the melter pressure control air addition port and at the HEME inlet. At both locations, the particulate was measured with and without steam to the film cooler while the melter was idled at about 1450 degrees Celsius. Additional determinations were made at the melter location during feeding and during idling at 1150 degrees Celsius rather than 1450 degrees Celsius (both with no steam to the film cooler). Deposition of particulates upstream of the melter sample point may have, and most likely did occur in each run, so the particulate concentrations measured do no necessarily reflect the total particulate emission at the melt surface. However, the data may be used in a relative sense to judge the system performance.
Date: November 1, 1997
Creator: Zamecnik, J.R.
Partner: UNT Libraries Government Documents Department

Phosphate Bonded Solidification of Radioactive Incinerator Wastes

Description: The incinerator at the Department of Energy Savannah River Site burns low level radioactive and hazardous waste. Ash and scrubber system waste streams are generated during the incineration process. Phosphate Ceramic technology is being tested to verify the ash and scrubber waste streams can be stabilized using this solidification method. Acceptance criteria for the solid waste forms include leachability, bleed water, compression testing, and permeability. Other testing on the waste forms include x-ray diffraction and scanning electron microscopy.
Date: April 13, 1999
Creator: Walker, B. W.
Partner: UNT Libraries Government Documents Department

Radiological engineering evaluation of the delay time line air scrubber located at the Clinton P. Anderson Meson Physics Facility (LAMPF)

Description: The purpose of this study was to determine the effects of the addition of an air scrubber to an already existing delay line and whether it would scrub {sup 11}CO{sub 2}. There were three main objectives of this study. The first objective was to determine the scrubbing efficiency of the scrubber. The scrubbing efficiency was then used to predict the dose rates in the scrubber area and compare those values with measurements from radiological surveys. The third objective was to determine if the shield blocks were effective in reducing the dose rates in the scrubber area. The activities were measured before and during scrubber operation and this information was used to calculate the scrubbing efficiency and the efficiency of {sup 11}CO{sub 2} removal was determined to be around 50%. Microshield was then used to predict dose rates and compared those values with measurements from radiological surveys. This was also used to determine the that the shield blocks around the scrubber were effective in reducing the dose rates from the radiation field produced by the radionuclides in the scrubber.
Date: May 1, 1996
Creator: Huneycutt, S. E.
Partner: UNT Libraries Government Documents Department

REDUCTION OF INHERENT MERCURY EMISSIONS IN PC COMBUSTION

Description: Oxidized mercury has been shown to be more easily removed from power plant flue gas by existing air pollution control equipment (e.g., wet scrubbers) than elemental mercury. The factors that determine how mercury is converted to the oxidized form in practical systems are, however, unknown. The present research focuses on developing an elementary, homogeneous mechanism that describes the oxidation of mercury by chlorine species as it occurs in practical furnaces. The goal is to use this mechanism (1) as a component in an overall homogeneous/heterogeneous mechanism that describes mercury behavior, and (2) to suggest low cost/low impact means of promoting mercury oxidation in furnaces. The results suggest an important role for Hg+Cl {r_arrow} HgCl and HgCl + Cl {r_arrow} HgCl{sub 2}. Here, the Cl is derived by radical attack on HCl in the high-temperature environment. The results suggest that the oxidation occurs during the time that the gases cool to room temperature. The high Cl concentrations from the flame persist into the quench region and provide for the oxidation of Hg to HgCl{sub 2} under lower temperatures where the products are stable. Under this mechanism, no significant HgCl{sub 2} is actually present at the higher temperatures where oxidized mercury is often reported in the literature (e.g., 900 C). Instead, all oxidation occurs as these gases are quenched. The results suggest that means of promoting Cl concentrations in the furnace will increase oxidation.
Date: August 26, 2000
Creator: Kramlich, John C. & Sliger, Rebecca N.
Partner: UNT Libraries Government Documents Department

Integration of thickener underflow into thermal dryer circuit. Final report

Description: A large number of coal preparation plants in the United States are troubled with coal fines and associated plant operation problems. As part of their process, these plants use thermal dryers for producing product coal, cyclones for first-stage recovery of coal fines, and wet scrubbers for the second-stage removal of coal fines carry-over from the dryer exhaust gas. The first challenge for these plants is to recover the clean ultra-fine coal captured in the scrubbers rather than to dispose of it in settling ponds. The second challenge is to mitigate the over-dry fine coal dusting problems in the dryer product. Prior to the completion of this program, the difficulties of the first challenge involving the recovery and use of fine clean coal from the thermal dryer scrubber effluent had not been solved. The second challenge, controlling fine coal dusting, was previously met by applying a solution of surfactants and process water to the over-dry coal fraction. As a result of the demonstration provided by the performance of this program, the implementation of a simple process improvement, involving the use of a thickener in combination with a belt press, simultaneously solved both challenges: the de-dusting and the dryer scrubber effluent recovery issues. The objective of this project was to: (1) Use a clean coal thickener with a squeeze belt press to recover the ultra-fine coal in dryer scrubber effluent; (2) Demonstrate that the coal-water mixture (CWM) produced from scrubber sludge of a thermal dryer can be used as a dust suppressant. The thickener/belt press system has increased the production of JWRI Mine Number 4 by approximately 0.7%. This production increase was accomplished by recovering and re-using 3 metric tons/hr (3.3 tons/hr) of coal fines that were previously sent to holding ponds, returning this as a 50% CWM to de-dust the 430 ...
Date: December 31, 1998
Creator: McClaine, A.W. & Breault, R.W.
Partner: UNT Libraries Government Documents Department

A method for the removal of elemental mercury from a gas stream

Description: A method is provided to remove elemental mercury from a gas stream by reacting the gas stream with an oxidizing solution to convert the elemental mercury to soluble mercury compounds. Other constituents are also oxidized. The gas stream is then passed through a wet scrubber to remove the mercuric compounds and oxidized constituents.
Date: December 1, 1997
Creator: Mendelsohn, Marshall H. & Huang, Hann-Sheng
Partner: UNT Libraries Government Documents Department

Technical letter report: Submerged bed scrubber sediment resuspension testing for the Hanford Waste Vitrification Plant

Description: During-vitrification operations in the Hanford Waste Vitrification Plant (HWVP), some feed components will be vented from the melter to the melter offgas cleaning equipment. The current HWVP reference process for melter off.-gas treatment includes a submerged bed scrubber (SBS) to provide the first stage of off-gas scrubbing and quenching. During most melter/off-gas test runs at Pacific Northwest Laboratory (PNL) with the Pilot Scale Ceramic Melter (PSCM) and at the West Valley Demonstration Project (WVDP), no significant quantities of sedimentation were accumulated in the SBS scrub tank. However, during test run SF-12, conducted at West Valley, approximately 6 in. of sedimentation accumulated in the scrub tank. This raised concerns that a similar accumulation could occur with the HWVP SBS, If such an accumulation rate occurred during a sustained melter run, the SBS would soon cease to function. To alleviate the potential for sedimentation buildup, the HWVP SBS design includes a sparge ring at the bottom of the scrub tank. The sparge ring will be operated intermittently to prevent buildup of solids which could interfere with circulation with the SBS Scrub tank. This report presents the results of testing conducted to evaluate the effectiveness of the HWVP sparge ring design. Section 2 contains-the conclusions and recommendations; Section 3 summarizes the objectives; Section 4 describes the equipment and materials used; Section 5 gives the experimental approach; and Section 6 discusses the results. The appendices contain procedures for sediment resuspension testing and particle size distribution data for silica and sediment.
Date: March 1, 1996
Creator: Schmidt, A.J. & Herrington, M.G.
Partner: UNT Libraries Government Documents Department