Analysis of Engineering Design Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot (2002) / Chapter Skim
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3 AEA Silver IITM Technology Package
3 AEA Silver IITM Technology Package
Pages 33-70
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From page 33... ...
Other solid, liquid, and gaseous effluents from various process units are collected, separated, treated, and tested to prepare them for safe discharge from the plant. Table 3-1 summarizes key plant performance requirements used in developing the SILVER II™ technology package.
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From page 34... ...
Spent C;~bon DPE Suits DEMlLlTARIZATION OF ASSEMBLED CHEMICAL WEaPONS AT BLUE GRASS ARMY DEPOT Mw~itions Prqocw Nbrta~ ~sas~ M~ aur~t~s o f ., ,~. Bodios _ , I Burster Wedl Multipurpose Demil Machine Nose PIUDS/FUZB Well CEPS ~Burster Washolit (H ~lY)
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From page 35... ...
AEA SILVER llrM TECHNOLOGY PACKAGE - - ~ Metal Parts Offoas Treatment _ _, , cat m u' :: ~ O tn ~ ~ ~ ~ ~ (D u' _. An SILVER 11 Agent Main Treatment Circuit r Polish Circuit SILVER 11 Energetic Main Treatment Circuit 1 Polish Circuit AgCI {H only)
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From page 36... ...
. submitted to PMACWA for a full-scale pilot plant at Blue Grass Army Depot (AEA, 2001a)
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From page 37... ...
The slurry is discharged through a pipeline in a manner that limits the content of the pipe to no greater than 20 weight percent propellant. The energetics slurry then flows into the energetics slurry feed tank (AEA, 2001a)
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From page 38... ...
Direct current is applied to the electrochemical cells at a potential of 2 volts, resulting in an electrochemical reaction that generates Ag2+ ions. Since the Ag2+ ions simply mediate the reaction process, the overall reaction across the anolyte and catholyte is essentially the reaction of the organic feed with nitric acid, forming NOX, water, CO2, and inor.
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From page 39... ...
HNO3 recycle T NOx reformer rMain 1 anolyte tank NOx, CO2, CO, O2 y: Cond~ .~ Memb~ne . .:.` Main'"''~ircuit cell pJacks | Catholyte recycle ~ ~q CO!
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From page 40... ...
Subsequently, this slurry is dewatered in a centrifuge to approximately 50 weight percent AgCl, with the remainder of the slurry consisting of water, nitric acid, silver nitrate, and trace amounts of other materials in the anolyte loop. The SILVER II™ polishing circuits for both agent and energetics systems continuously produce a larger stream of AgC1 than what is produced in the main circuit when H or HD feeds are being processed.
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From page 41... ...
. For a full-scale facility at Blue Grass, the main processing circuits would consist of six operating cell stacks of 48 cells each for agent and six operating stacks of 42 cells each for the energetics.
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From page 42... ...
Therefore, additional unit operations yet to be defined may be required to deal with this issue. Processing and Treatment of Metal Parts, Dunnage, and Other Solid Waste Meta/ Parts Processing Metal parts, fuzes, and fiberglass segments of shipping and firing tubes from the munitions disassembly lines, and drums containing particulate matter from the candle filters and cyclones of the gaseous effluent treatment systems are conveyed in bins to one of two MPTs for decontamination to the SX level.
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From page 43... ...
When processing DPE suit material, HCl will also be present in the sweep gas stream. The process gases are treated in a gaseous effluent treatment system (described in the following section)
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From page 44... ...
At this point in the gaseous effluent system, offgas from the NOX reformers for agent and energetics SILVER II™ systems is added to the offgas from the MPT and DTS systems, respectively. Offgas from the NOX reformer of the agent SILVER II™ system is preheated prior to being added to the MPT gaseous effluent gas stream.
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From page 45... ...
Title Organization and Report Number Engineering tests Propellant grinding test M28 and Comp B SILVER II™ processing trials DMMP (agent simulant) 500-hr run SILVER II™ processing trials Laborator~v-scale tests Eco Logic, Inc., no report number, November 5, 2001 AEA, 20/3034/13/006 AEA, 20/3034/13/006 High-shear mixer trials for the 12-kW SILVER II™ plant AEA, 20/3034/002 Hydrocyclone trials for the 12-kW SILVER II™ plant AEA, 20/3034/001 E7MO1 SILVER II™_organic transfer AEA, 20/3034/007 Fluoride mobility report AEA, 20/3034/011 Fluoride removal system AEA, 20/3034/009 Cell membrane life tests AEA, 20/3034/13/004 Investigation into the 12-kW SILVER II™ plant membrane failures AEA, 20/3034/13/005 Silver recovery from silver chloride AEA, 20/3034/13/003 Evaporator trials for the full-scale SILVER II™ EDP plant AEA, 20/3034/13/008 CST/CATOX testing Desktop studies (literature surveys)
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From page 46... ...
These activities provided data needed to complete a fullscale design for the EDP for a facility at Blue Grass Army Depot. Summaries of the tests and studies performed and used in the development of the final EDP for AEA's SILVER II™ technology package are discussed in the fol.
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From page 47... ...
· Demonstrate that organic materials, silver, acid, and water in the catholyte circuit can be effectively managed over prolonged operational periods. · Demonstrate that process impurities that build up in the anolyte circuit can be effectively managed over prolonged operational periods.
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From page 48... ...
The committee notes that other research in mediated electrochemical processes has shown that the coulombic or electrochemical efficiency of the process is directly proportional to the concentration of the material being oxidized and rapidly decreases as the destruction approaches 100 percent- that is, as the concentration of oxidizable material becomes very small (Chiba et al., 1995~. The high-shear mixers and hydrocyclones in the anolyte and catholyte circuits, along with trace heating and elimination of dead legs, successfully maintained the particulate energetics in the anolyte and catholyte circuits in a finely divided state.
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From page 49... ...
The high-shear mixers must operate in the presence of energetics and energetic breakdown products and in the highly acidic conditions that are present in the anolyte and catholyte feed tanks of the energetics SILVER II™ plant. Most of the typical industrial solidliquid mixers were found to be unsuitable for this application.
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From page 50... ...
Based on results of these tests, only the high-shear vortex mixer would meet operational goals. High-shear vortex mixers were installed in the anolyte and catholyte feed tanks for the EDS II tests of the 12-kW SILVER II™ plant and performed well during the tests with Composition B and M28 propellant.
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From page 51... ...
In each set of conditions, the change in concentration of fluoride with time in the anolyte and catholyte feed tanks and in the offgas was tracked after the introduction of sodium fluoride equivalent to 0.1 M in the anolyte solution- at the beginning of each run (AEA, 2001k)
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From page 52... ...
The committee notes that the analysis of the cell membrane failure that occurred in the 500-hour DMMP (discussed in the next section) suggests that the cell membrane tests did not represent worst-case conditions for membrane life under actual operating conditions and that limited credence can be given to the conclusions from this test (AEA, 2001k)
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From page 53... ...
Further, it is not clear that additional membrane failure mechanisms will not be experienced as a consequence of flow and pressure variations in the six cell stacks of up to 48 cells each, recommended for the full-scale facility at Blue Grass. Si/ver Recovery from Si/ver Chloride These tests were conducted to provide sufficient data to select a silver recovery method (AEA, 2001n)
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From page 54... ...
In particular, foaming may result from the presence of organic materials, and fluorides and chlorides may migrate to the NOX reformer system and pose added materials challenges. According to the EDP, a full-scale SILVER II™ plant at Blue Grass would include an evaporator circuit to reduce the volume of waste that arises from metals and mineral acids accumulated in the IRS.
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From page 55... ...
. The study recommends that these other initiation sources be studied in a comprehensive safety evaluation program that would assess the potential hazards that might accompany demilitarization of M55 rockets with M28 propellant.7 CST/CATOX Unit Testing Although not part of AEA's SILVER II™ EDS II testing program, the CST/CATOX unit tests for EDS I conducted by Parsons/Honeywell are reviewed here since they serve as the basis for design decisions on the DTS and DTS offgas emissions control systems for the SILVER II™ technology package.
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From page 56... ...
. improving the temperature controls of the CATOX unit to prevent over-temperature damage to the catalyst, as occurred in earlier testing improved mitigation of solids separation upstream of the CATOX unit to prevent fouling/ plugging of the catalyst by fine particulates changes in the design and operating conditions of the CST and CATOX units to reduce the formation of dioxins and furans when processing DPE material In view of the Parsons experience with CST testing, it seems advisable for additional testing to be performed on the enclosed auger design for the SILVER II™ dunnage treater to ensure that auger plugging will not result in excessive downtime and maintenance.
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From page 57... ...
machine with modification for a water jet BOOM, which uses a high-pressure water wash to remove the energetic material from the burster tube. The committee notes that a similar system has been proposed as part of the Parsons/Honeywell technology package put forth for disposal of the mustard agent munitions at Pueblo Chemical Depot (NRC, 2001a)
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From page 58... ...
Other testing experience and process changes indicating the immaturity of the SILVER II™ process include these: · Cell membrane failures not predicted by tests of cell membrane life and lack of long-term testing on feeds containing C1 and F Planned removal of lead oxide using a formic acid wash without prior demonstration in a multicell configuration.
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From page 59... ...
may occur, requiring longerprocessing times. The gaseous effluent treatment system for the MPT is similar to that used in the Parsons/Honeywell WHEAT technology.
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From page 60... ...
With regard to dioxin/furan formation, AEA states that the use of carbon and HEPA filters downstream of the CATOX units should adequately control emissions of these materials. As noted earlier, testing of the CATOX units of the Parsons/Honeywell WHEAT process has revealed the need for changes in the design and operating conditions of both the CST and the CATOX units in order to reduce the formation of dioxins and furans when processing DPE suit material (Parsons, 20011.
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From page 61... ...
Agent: same as anolyte circuit. Energetics: piping to be PFA-lined carbon steel; pumps to be titanium; valves to be PFA-lined ductile cast iron; agitators to be PTFE-coated stainless steel; seals and gaskets to be Kalrez, ~FE, or PTFE-clad.
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From page 62... ...
electrochemical cells, because their anolyte circuits are separate and the catholyte circuit is much less likely to be the source of failure (AEA, 2001a)
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From page 63... ...
As noted earlier, CO emissions at a SILVER II™ facility at Blue Grass would be significant, 90 ton/yr, even with the anticipated 98-99 percent efficiency of the CATOX units. The liquid discharges from the anolyte circuit, catholyte circuit, NOX reformer, and caustic scrubber were sampled and analyzed for metals and organics.
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From page 64... ...
SILVER II™ will require a Subpart X permit, for which there is no precedent. The committee also notes that the SILVER II™ total solution technology package for Blue Grass entails a very large scale-up from 3 cells during Demo II and EDS II testing to 432 cells for agent destruction and 378 cells for energetics destruction, which will be a concern for permit writers.9 In seeking an RD&D permit,~° for example, permit writers would need to be assured that the applicant knows where the materials, particularly the metals, are going, which in turn demands that permitters have confidence in the mass balances for the technology.
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From page 65... ...
- Carbon filter operating conditions Maximum operating temperature Carbon replacement rate ~ffgas flow rate - Emissions monitoring Continuous emissions measurements of CO/CO2/O2 in vent gases Continuous measurement of NOx emissions in vent gases Continuous emissions measurements of total hydrocarbons hlonne emissions monitoring Hold-test-release protocols It is clear from the preceding list that permitting will be challenging for the AEA SILVER II™ technology package for Blue Grass. ASSESSMENT OF OVERARCHING TECHNICAL ISSUES Overall Engineering Design Package The overall EDP offered for AEA's SILVER II™ technology has grown in complexity from what was presented during the Demo I and Demo II phases of the ACWA program.
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From page 66... ...
· The technology provider now plans to use electrical steam heaters and internal steam recirculation for the MPT. Although this configuration seems feasible and is a variant of the MPT technology tested for the Parsons/Honeywell WHEAT technology package, the committee notes that it has not been demonstrated in its proposed configuration and that the steam-reactant environment may pose significant materials technology challenges and result in different chemical loadings in the gaseous effluent treatment system.
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From page 67... ...
AEA states (AEA, 20010) that the anolyte and catholyte circuits use a 'multi-clone' arrangement of hydrocyclones with their overflows combining to a single process line, which is then fed to the electrochemical cells.
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From page 68... ...
This is no longer relevant because the shredded wood and DPE suit material will be treated in a dunnage treater similar in design to the CST of the Parsons/Honeywell technology package demonstrated in EDS I testing, and which achieved SX decontaminalion. The enclosed auger design of the dunnage treater used in AEA's DTS remains to be demonstrated.
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From page 69... ...
Cell membrane failures are not predicted by cell membrane life tests, and there has been no longterm testing on feeds containing C1 and F There are plans for the removal of lead oxide using formic acid wash without prior demonstration in a multicell configuration.
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From page 70... ...
AEA-6. The committee believes that a very complex permitting process will be required for the SILVER II™ technology package for Blue Grass, and that there is a need to develop a very comprehensive set of performance data to allow the operating conditions to be established even after a facility has been designed and built.
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