Assessment of Supercritical Water Oxidation System Testing for the Blue Grass Chemical Agent Destruction Pilot Plant (2013)

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1 Introduction The United States joined the 1993 Convention on the to growing public opposition to incineration, the Army de- Prohibition of the Development, Production, Stockpiling veloped alternative processes to neutralize chemical agents and Use of Chemical Weapons and on their Destruction by hydrolysis. These processes were used to destroy the VX (CWC) in April 1997. Under the CWC the United States, nerve agent at Newport, Indiana, and the mustard agent at along with 188 other states as of 2012, agreed to eliminate Aberdeen, Maryland. Only bulk stored agent was present at their entire stockpiles of chemical weapons. The terms of the those two sites. CWC originally mandated destruction of the U.S. stockpile In 1996, public opposition to incineration in Kentucky by April 2007. The CWC allowed for one 5-year extension and Colorado caused Congress to enact Public Law 104-201, to this mandate, and the U.S. availed itself of this extension. which instructed the Department of Defense to Thus, the deadline for full stockpile destruction was extended until April 2012. Over 90 percent of the U.S. stockpile of conduct an assessment of the chemical demilitarization pro- chemical agent and munitions had been disposed of by gram for destruction of assembled chemical munitions and this extended deadline. Of nine stockpile sites, seven have of the alternative demilitarization technologies and processes completed agent destruction and the disposal facilities are (other than incineration) that could be used for the destruc- tion of the lethal chemical agents that are associated with either closed or undergoing closure.1 As of the writing of this these munitions. (PL 104-201, section 142) report, the Pueblo Chemical Agent Destruction Pilot Plant, in Colorado, and the Blue Grass Chemical Agent Destruction As a result, the Program Manager for Assembled Chemical Pilot Plant (BGCAPP), in Kentucky, are being constructed Weapons Assessment3 was established to to dispose of the remainder of the U.S. stockpile. Initially, the U.S. Army, following recommendations identify and demonstrate not less than two alternatives to from the National Research Council (NRC), chose incinera- the baseline incineration process for the demilitarization of tion as the destruction method at all sites. Citizens in some assembled chemical munitions. (PL 104-208, section 8065) states with stockpile storage sites, however, opposed incin- eration because they believed it was impossible to determine Following a detailed selection process among proposed the exact nature of the effluents from the exhaust stacks at methods for destroying the weapons at Blue Grass Army the incineration plants. In the end, incineration was used Depot, Kentucky, the Program Manager for Assembled at four of the eight storage sites in the continental United Chemical Weapons Assessment selected technologies us- States.2 The stockpiles at each of these four sites consisted ing hydrolysis to destroy both agent and energetic material of assembled munitions and bulk stored agent. In response (propellant, fuzes, and bursters) streams (see NRC, 2002). Hydrolysis will destroy chemical agent to a permit-mandated 1These sites were the Aberdeen Chemical Agent Disposal Facility (Ab- 99.9 percent, and the resulting hydrolysates no longer exhibit erdeen, Maryland); Anniston Chemical Agent Disposal Facility (Anniston, the acute toxicity of the original chemical warfare agents.4 Alabama); Johnston Atoll Chemical Agent Disposal System (Johnston Atoll), Newport Chemical Agent Disposal Facility (Newport, Indiana); 3The Program Manager for Assembled Chemical Weapons Assessment Pine Bluff Chemical Agent Disposal Facility (Pine Bluff, Arkansas); Tooele has since been renamed the Program Manager for Assembled Chemical Chemical Agent Disposal Facility (Tooele, Utah); and the Umatilla Chemi- Weapons Alternatives, its current name. cal Agent Disposal Facility (Umatilla, Oregon). 4Personal communnication between Steven Mantooth, Blue Grass 2Anniston, Alabama; Pine Bluff, Arkansas; Tooele, Utah; and Umatilla, Chemical Agent Destruction Pilot Plant program office, and James Myska, Oregon. NRC study director, on February 5, 2013. 8 

INTRODUCTION 9 Metal recovered from muniƟons Metal to disposal Agent hydrolysate Agent EnergeƟcs EnergeƟcs hydrolysate Mixed hydrolysate Brine to SCWO SCWO reactors (4) disposal effluent Recycled quench water FIGURE 1-1  Simplified process diagram for the BGCAPP demilitarization process using hydrolysis followed by SCWO. At BGCAPP, the blended agent and energetics hydrolysates Figure 1-1 containing GB.6,7 The VX and GB will be demilitarized us- will be treated by a supercritical water oxidation (SCWO) ing caustic hydrolysis. Any energetic materials disposed of process to further process them into environmentally benign at BGCAPP will also be treated by caustic hydrolysis. The products. In total, roughly 6.1 million gallons of hydrolysate mustard agent will be hydrolyzed using hot water, although will have to be processed through the SCWO system.5 The at this writing an alternative process is being considered for SCWO hardware has been built, tested, and is being shipped the disposal of the mustard munitions because many of the to BGCAPP as of this writing. mustard artillery rounds contain solidified or gelled mustard heels, which can be difficult to wash out. STOCKPILE CHARACTERISTICS OVERALL BGCAPP DEMILITARIZATION PLAN The stockpile to be processed at BGCAPP consists of 115-mm M55 rockets containing GB (sarin) or VX (69,479 A simplified diagram of the demilitarization process total rounds); 155-mm M110 projectiles containing mustard planned for use at BGCAPP, including hydrolysis and the agent (H) and 155-mm M121 projectiles containing VX SCWO and water recovery system (WRS) processes, is (28,308 total rounds); and 3,977 8-in. M426 projectiles shown in Figure 1-1. Agent will be removed after mechani- cally breaching the munitions (1) using a sodium hydroxide 6Ibid. 7Conrad Whyne, Program Executive Officer, Assembled Chemical Weap- ons Alternatives, “Assembled Chemical Weapons Alternatives (ACWA) 5John Barton, chief scientist, Bechtel Parsons Blue Grass Team, “BGCAPP Program Update,” presentation to the Committee on Chemical Demilitariza- Process Overview,” presentation to the committee on January 7, 2013. tion on December 4, 2012. 

10 ASSESSMENT OF SUPERCRITICAL WATER OXIDATION SYSTEM TESTING FOR THE BGCAPP (or water in the case of mustard) washout process, then (2) single-phase fluid throughout the supercritical region (i.e., it producing hydrolysate that is still considered a toxic waste. does not separate into discernible liquid and gaseous phases). The agent hydrolysate will be mixed with hydrolysate result- However, at a given supercritical pressure its density (and ing from similar caustic treatment of the energetic materials other properties) can vary greatly as the temperature is var- removed from the munitions (3). This mixture will then be ied over a relatively small range. Of interest for processing, treated by the SCWO process (4) followed by a coupled water changes from a polar solvent at ambient conditions to reverse osmosis WRS for treating SCWO effluent (5). Some a nonpolar solvent at supercritical states. It then becomes an recovered water will be used as quench water in the SCWO excellent solvent for most nonpolar substances such as the units, and the remaining salt-containing WRS effluent will organic materials present in the chemical agents stockpiled then be disposed of off-site. at BGCAPP. Conversely, at supercritical conditions water At the time of this writing, the schedule for BGCAPP becomes a poor solvent for ionic materials such as salts. plant construction, systemization, and operation is not firmly If an organic compound is dissolved in supercritical set. The most recent schedule is shown in Figure 1-2. water and excess oxygen is also introduced and dissolved, This schedule shows that construction will be complete rapid and efficient oxidation of the organic compound can in mid-2017; systemization will proceed in parallel with take place. This is the basis for the SCWO process. SCWO construction and be complete by mid-2020. Agent process- reactors have been proposed and built for many purposes ing operations will begin in mid-2020 and be completed such as sewage waste disposal and the destruction of undesir- by the end of 2023. Plant closure will then commence and able pollutants such as polychlorinated biphenyls. A review be complete at the end of the first quarter of 2027. The of commercial-scale SCWO reactors and their performance BGCAPP project schedule is strikingly different from a is provided by Marrone (2012). He points out that many of typical industrial project schedule. This is a unique govern- the commercial SCWO installations have failed due to one ment project and is not subject to the usual schedule and of two factors: (1) unexpectedly high corrosion rates in the budget constraints of a commercial operation. The schedule reactor or heat exchangers or (2) salt buildup in the reactor. has slipped several times due to various budget issues and Thus, modern SCWO designs carefully incorporate methods congressional actions. Also, the SCWO system is presently for sidestepping or mitigating these two factors. expected to operate for only 2-3 years, after which it then The hydrolysates from the chemical neutralization of will be dismantled and disposed of. chemical agents and energetics contain organic components, making SCWO decomposition of them attractive. However, the hydrolysates also contain metallic components, which DESCRIPTION OF THE SCWO PROCESS are converted into salts during hydrolysate processing. Thus, The thermodynamic critical point for water is 704°F use of SCWO for agent destruction can be expected to face and 3,200 psia. Above these values, the water is described both of the problems inherent in the process: corrosion of as being in a supercritical state, and its properties differ the SCWO unit and heat exchangers, as well as solid salt greatly from those observed under more familiar conditions. buildup in the SCWO unit. First-of-a-kind (FOAK) testing Figure 1-3 is a phase diagram for water and the conditions of the BGCAPP SCWO units was meant to demonstrate that planned for the BGCAPP SCWO process. One important these potential problems have been successfully addressed in characteristic of supercritical water is that it behaves as a the SCWO system design to be used at BGCAPP. 2012- 2014- 2016- 2018- 2020- 2022- 2024- 2026- 2014 2016 2018 2020 2022 2024 2026 2028 Construction Systemization Agent processing Closure FIGURE 1-2  Program schedule for BGCAPP. SOURCE: Adapted from Joe Novad, Deputy Program Executive Officer, Assembled Chemical Weapons Alternatives, “Program Executive Office Assembled Chemical Weapons Alternatives Update,” presentation to the Committee on Chemical Demilitarization, April 9, 2013. Figure 1-2 

INTRODUCTION 11 5,000 4,500 Supercritical fluid 4,000 Planned BGCAPP SCWO operating conditions of 3,500 3,400 psia, 1200°F Pressure (psia) 3,206 psia 3,000 2,500 705°F 2,000 1,500 1,000 Liquid Gas (steam) 500 0 32 212 392 572 752 932 1112 Temperature (°F) FIGURE 1-3  Phase diagram for water showing the operating conditions planned for the BGCAPP SCWO process. SOURCE: Adapted from John Barton, chief scientist, Bechtel Parsons Blue Grass Team, “BGCAPP Process Overview,” presentation to the committee on January 7, 2013. The SCWO reactor pressure vessel is made of Hastelloy Figure 1-3 C-276. A Hastelloy C-276 sleeve is placed inside the pres- sure vessel, and a sacrificial titanium liner is placed inside the sleeve to prevent corrosion of the sleeve and pressure vessel. This liner does not serve any structural purpose and does not need to do any more than support its own weight. The change-out periods for the liners are based on corrosion data from testing and set to ensure that the liner thickness is not corroded through prior to replacement. An air purge between the sleeve and the pressure vessel prevents reactor contents from entering the space between the liner and the pressure vessel. Material is introduced into the SCWO reac- tor through ports in the reactor head. Titanium thermowells also protrude into the reactor from the head. These thermo­ wells hold thermocouples to monitor operating conditions. At the bottom of the reactor, quench water is used to cool the SCWO effluent. The materials have been chosen through a thorough series of assessments and tests to best handle the SCWO operational environment, and the design has matured over the course of more than a decade. During operations, the SCWO reactor will first be brought to its operating temperature and pressure. The pro- cess streams, including the blended hydrolysate streams, will then be injected into the reactor and immediately subjected to supercritical conditions. Figure 1-4 shows the overall SCWO reactor. Figure 1-5 is a more detailed drawing of the reactor. It shows the major pieces of the reactor and how they are assembled, where the feed nozzle enters the reactor, where the thermowells are placed in the reactor, and the process FIGURE 1-4  Exterior view of the overall SCWO reactor. SOURCE: Figure 1-4 outlet from the reactor. Personal communication between Steven Mantooth, Blue Grass Bitmapped Chemical Agent Destruction Pilot Plant program office, and James Myska, NRC study director, on August 1, 2013. 

12 ASSESSMENT OF SUPERCRITICAL WATER OXIDATION SYSTEM TESTING FOR THE BGCAPP WRS will be mixed with the brine stream and the mixture disposed of off-site. SCWO SYSTEM DESIGN AND FOAK TEST Feed nozzle OBJECTIVES As stated above, the difficulties associated with SCWO Flange studs processing—extreme corrosion conditions and potential salt buildup—require careful system design. The design of the SCWO system for BGCAPP is the result of a significant Top flange amount of prior assessment and testing that resulted in the Mounting lug choice of materials, design features, and processes to ad- dress these concerns.8 The FOAK tests were to confirm that the full-scale production system would meet the operational Thermowells/ requirements at BGCAPP. These tests used simulated hy- thermocouples drolysates that closely resembled the concentrations of all Vessel chemical species expected in the blended agent and energetic mixed feeds that will be processed at BGCAPP. Corrosion rates were measured under the flow rates and processing conditions expected at BGCAPP, including SCWO reactor start-up and shutdown. The system was also tested to deter- mine whether modifications to operational conditions and chemical pretreatment of the blended hydrolysate simulants controlled salt buildup within acceptable limits. The combined SCWO/WRS system was not tested as a coupled unit. This will be done during the BGCAPP sys- temization period. Bottom flange STATEMENT OF TASK The NRC will establish a committee for an assessment Process outlet of FOAK factory acceptance test performance results of the General Atomics SCWO system design and recommenda- FIGURE 1-5  Detailed drawing of the reactor showing the main tions for testing during systemization at BGCAPP: parts of the reactor and how they are assembled, where the feed nozzle enters the reactor, where the thermowells are placed in the •  xamine test reports and results as made available E reactor, and the process outlet from the reactor. SOURCE: Personal Figure 1-5 communication between Steven Mantooth, Blue Grass Chemical within the time frame of this study with respect to Agent Destruction Pilot Plant program office, and James Myska, verification of the functionality of tested SCWO NRC study director, on August 1, 2013. system components, operability under normal and abnormal conditions, and performance in meeting throughput and other operational requirements; THE INTEGRATED SCWO/WRS SYSTEM •  rovide an evaluation of how well the test data sup- P port conclusions reached; This report is chiefly concerned with the SCWO system •  rovide recommendations on SCWO systemization P and with its interactions with the WRS. An equipment and testing at BGCAPP inclusive of durability testing; flow diagram for this part of the BGCAPP installation is and shown in more detail in Figure 1-6. •  iscuss systemization testing objectives and con- D The effluent from the SCWO process will pass through cepts in consideration of committee findings from the reverse osmosis water recovery system, where it will the BGCAPP Water Recovery System (WRS) study be separated into clean water (less than 500 mg/L of total report. dissolved solids) and a brine stream. A portion of the clean water will be recycled for use as a quench purge stream 8See NRC, Interim Design Assessment for the Blue Grass Chemical Agent introduced near the outlet of the SCWO units to reduce the Destruction Pilot Plant (2005) and Letter Report of Review and Assessment outlet temperature of the effluent stream and to dissolve the of the Proposals for Design and Operation of Designated Chemical Agent Destruction Pilot Plants (DCAPP-Blue Grass) (2006); these two NRC salts present in that stream. Any excess clean water from the reports addressed design. 

INTRODUCTION 13 Offgas HP air HP air to filter compressor manifolds Condensate from Offgas other processes duct Agent hydrolysate heater EnergeƟcs hydrolysate HP fuel pump Ipa pump Gas Salt analyzers Solid feed addiƟves S Hydrolysate Hp hydrolysate HP hydrolysate Acids blend tanks pump Pump Wet feed addiƟves NaOH HP water pump TOC Hydrolysate blend/ HPQuench pump quench pump analyzer SCWO Batch holding batch holding effluent tank tank heaƟng skid Feed Module tank LP gas- Lp gas SCWO liquid Liquid reactor separator Separator Emergency relief tank HP gas- Hp gas - liquid Liquid Off -spec separator Separator tank Reactor Effluent heat exchanger Module Antiscalant Coagulant RO units (3) RO RO permeate storage From SCWO effluent tanks To RO permeate tanks SCWO Multimedia Canister High- effluent filters filters pressure tank (6) (3) pump RO reject pumps Recycle pump To RO reject tanks Cooling tower and Water steam softener blowdown Spent regenerant to RO reject tank FIGURE 1-6  Flow diagram of SCWO system and reverse osmosis WRS. SOURCE: Adapted from Dan Jensen, advanced process system pro- gram manager, General Atomics, “SCWO System Equipment and Layout,” presentation to the committee on January 7, 2013; and NRC, 2012. 1-3 composite REPORT OVERVIEW testing have been put into the current SCWO design. This has been addressed in previous NRC reports.9 As can be seen This report addresses progress in the development, from the statement of task, however, this committee was not construction, and FOAK testing of the SCWO system. It charged to assess the design of the SCWO system to be used also considers the interactions between the SCWO system at BGCAPP or to address its scientific bases, and this report and its associated reverse osmosis WRS. The report presents does not do so. The committee does not review the techni- findings and recommendations for the systemization and cal literature on SCWO but rather accepts the technology’s preoperational testing of these combined process elements. It also addresses the adequacy of the BGCAPP response to findings and recommendations in the 2012 NRC report The 9For example, Analysis of Engineering Design Studies for Demilitariza- Blue Grass Chemical Agent Destruction Pilot Plant’s Water tion of Assembled Chemical Weapons at Blue Grass Army Depot (2002); Recovery System (Letter Report). Update on the Engineering Design Studies Evaluated in the NRC Report, Analysis of Engineering Design Studies for Demilitarization of Assembled SCWO is a mature technology with a strong scientific Chemical Weapons at Blue Grass Army Depot (Letter Report) (2002); Inter- and engineering base underlying it. As noted in the preceding im Design Assessment for the Blue Grass Chemical Agent Destruction Pilot section, “SCWO System Design and FOAK Test Objectives,” Plant (2005); and Letter Report of Review and Assessment of the Proposals a significant amount of design work, laboratory work, and for Design and Operation of Designated Chemical Agent Destruction Pilot Plants (DCAPP-Blue Grass) (2006). 

14 ASSESSMENT OF SUPERCRITICAL WATER OXIDATION SYSTEM TESTING FOR THE BGCAPP maturity and focuses on its task of examining and evaluating units when delivered, installed, and systemized at BGCAPP a specific set of test data. and offers committee observations about the systemization Accordingly, this report is confined to a review and as- process. Finally, Chapter 4 addresses the response to The sessment of the FOAK testing of the SCWO system hardware Blue Grass Chemical Agent Destruction Pilot Plant’s Water that will be used at BGCAPP, an assessment of the BGCAPP Recovery System (Letter Report) and discusses and makes response to the 2012 NRC WRS report, and making recom- recommendations for the systemization of the combined mendations for moving forward to systemization. In the SCWO/WRS systems. In each chapter, findings and recom- course of its work, the committee made use of a broad range mendations are set forth based on the observations of the of sources of technical information, including the following: review committee. The statement of task only directs the committee to •  est Report for Supercritical Water Oxidation (SCWO) T examine the FOAK testing results for the SCWO unit that First-of-a-Kind (FOAK) Test, April, Preliminary Draft was tested and the systemization of the coupled SCWO/WRS (BPBGT, 2013); when installed at BGCAPP. Factors beyond those addressed •  est Plan for Supercritical Water Oxidation (SCWO) T in the FOAK testing are not examined unless the committee First-of-a-Kind (FOAK) Test, Rev. 1, July (BPBGT, believed they could potentially affect the operation of the 2012); systemized SCWO/WRS. •  upercritical Water Oxidation: Current Status of S Full-Scale Commercial Activity for Waste Destruc- REFERENCES tion (Marrone, 2012); •  ench-Scale Evaluation of GB Hydrolysis, TRRP B BPBGT (Bechtel Parsons Blue Grass Team). 2005. Technical Risk Reduc- tion Project (TRRP) 07 and 09 Report on Supercritical Water Oxidation #02a Phase II Test Report, Rev. 0 (Malloy et al., Blended Feed Performance Tests, Rev. 0, April. Richmond, Ky.: Blue 2007); Grass Chemical Agent Destruction Pilot Plant Program Office. •  echnical Risk Reduction Project (TRRP) 07 and 09 T BPBGT. 2012. Test Plan for Supercritical Water Oxidation (SCWO) First- Report on Supercritical Water Oxidation Blended of-a-Kind (FOAK) Test, Rev. 1, July. Richmond, Ky.: Blue Grass Chemi- Feed Performance Tests, Rev. 0 (BPBGT, 2005); cal Agent Destruction Pilot Plant Program Office. BPBGT. 2013. Test Report for Supercritical Water Oxidation (SCWO) First- • Process flow diagrams for the SCWO system; of-a-Kind (FOAK) Test, April, Preliminary Draft. Richmond, Ky.: Blue • Briefings from BGCAPP and system contractor staff; Grass Chemical Agent Destruction Pilot Plant Program Office. •  ounds of technical questions and answers with the R Malloy IV, T.A, L. Dejarme, C. Fricker, J. Guinan, G.D. Lecakes, and A. BGCAPP staff; and Shaffer. 2007. Bench-Scale Evaluation of GB Hydrolysis, TRRP #02a •  etailed discussions with BGCAPP and contractor D Phase II Test Report, Rev. 0, October 2. Aberdeen, Md.: Battelle. Marrone, P.A. 2012. Supercritical Water Oxidation: Current Status of Full- staff. Scale Commercial Activity for Waste Destruction. Available online at http://issf2012.com/handouts/documents/384_004.pdf. Last accessed This report is organized into four chapters. Following December 31, 2012. the general introduction in Chapter 1, Chapter 2 reviews NRC (National Research Council). 2002. Analysis of Engineering Design the FOAK test results and assesses whether the tests have Studies for Demilitarization of Assembled Chemical Weapons at Blue Grass Army Depot. Washington, D.C.: The National Academies Press. adequately addressed concerns about corrosion rates and salt NRC. 2012. The Blue Grass Chemical Agent Destruction Pilot Plant's Wa- buildup and removal. Chapter 3 addresses the installation, ter Recovery System (Letter Report). Washington, D.C.: The National scheduling, staffing, and testing envisioned for the SCWO Academies Press.