bgcapp cyanide treatment december 11, 2013

BGCAPP Cyanide Treatment

December 11, 2013

Presented to:

Kentucky Chemical Demilitarization Citizens’ Advisory Commission and

Chemical Destruction Community Advisory Board

Presented by:

Jeff Brubaker, ACWA Site Manager

John Barton, Systems Contractor Chief Scientist

A Partnership for Safe Chemical Weapons Destruction

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The Technical Challenge

Neutralizing rocket warhead explosives poses unique technical challenge at Blue Grass

Cyanide formation expected during energetics neutralization process, trapped in caustic liquid energetics hydrolysate

Cyanide produced during energetics neutralization processisn’t a public risk, but if not treated, may require additional protective measures during future plant operations where cyanide may present a worker hazard

Specific cyanide hazards may be present during Supercritical Water Oxidation Process feed preparation

BGCAPP focused on treating hazard today, to better protect operations workers for tomorrow


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Treatment Approach

Year long collaborative effort among BGCAPP scientists, engineers and corporate subject matter experts

Mission focused on safely and efficiently treating cyanide hazard during energetics neutralization processing

Focus on energetics neutralization process

– Portion of process where cyanide first occurs

– Un-manned, automated process (i.e. no workers)

– Upstream before Supercritical Water Oxidation Process(where cyanide could pose worker hazard)


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A Safe Solution

Enhancing auxiliary systems to the Energetics Neutralization Reactors to increase operating temperature

– Safely and efficiently destroys cyanide

– Does not change the neutralization process

– Does not alter the Supercritical Water Oxidation process

– Does not impact weapons destruction baseline schedule


Neutralization of energetics (explosive) and aluminum with hot caustic under BGCAPP-specific process conditions occurs in the energetics batch hydrolyzers

Hydrolysate will contain many secondary liquid byproducts that include ammonia, nitrate, formate, cyanide and many other decomposition products.

Energetics destruction is verified before hydrolysate is released to Hydrolysate Storage Area (HSA) and subsequent secondary Supercritical Water Oxidation process

Energetics Neutralization

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Energetics Batch Hydrolyzers equipment will be used during the BGCAPP energetics neutralization process.

Small piece of energetics in an aluminum pan


Hazard Evaluation

BGCAPP confirmed cyanide ion formation during the energetics neutralization process using a series of bench-scale tests performed in late 2012

Without treatment, additional protective measures may be needed during future plant operations where cyanide may present a worker hazard

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Energetics Hydrolysate


Technical Background:Energetics Neutralization Process

HSS

Off-gas to MDB filter banks

Hydrolysate Storage Area (HSA)

EBH – Energetics Batch Hydrolyzer ENR – Energetics Neutralization Reactor SCWO – Supercritical Water Oxidation OTE – Off-gas treatment for EBH (acid scrubber) OTM – Off-gas Treatment System APR – Aluminum Precipitation Reactor AFS – Aluminum Filtration System

ENR

Munitions Demilitarization Building (MDB)

OTE effluent

Off-gas to OTE

Off-gas to OTM

EBH

216°F, 1 atm

240°F, 1.7 atm

AFS

Air

Acid

Off-gas to carbon

canister

Off-gas to atmosphere

Filter cake

APR

Waste Packaging

SCWO Feed

System

Supercritical Water Oxidation (SCWO) Processing Building(SPB)

Off-gas to SCWO building

140°F, 1 atm

Scrubber condensate

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Technical Verification:Bench-Scale Characterization Tests

Mettler RC1® Calorimeter Reactor at Battelle’s HERLA Used to Simulate BGCAPPEBH and ENR Operations

Aluminum Precipitation System Used to Simulate BGCAPP APR and AFS Operations

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Verification Results

Cyanide is produced during energetics neutralization process(400-600 milligrams per liter (mg/L)

Without treatment, cyanide will persist at decreasing levels within energetics hydrolysate streams as they are processed through to SCWO Process Building

Because high pH is maintained in the Munitions Demilitarization Building and HSA, hydrogen cyanide off-gassing is not a significant hazard in those areas

Significant levels of hydrogen cyanide will off-gas inside the aluminum precipitation reactor system (reactor headspace) during acidification of energetics hydrolysate (> 25 mg/m3) in the SCWO Processing Building

Significant levels of hydrogen cyanide will also off-gas in the aluminum filtration system and from produced filter cake(> 5 mg/m3)

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Cyanide Health Limits

National Institute of Occupational Safety & Health assigns short-term exposure limit, 15-minute time-weighted average, of 5 mg/m3 for hydrogen cyanide in air

Centers for Disease Control assign an Immediately Dangerous to Life or Health limit of 25 mg/m3 for hydrogen cyanide in air

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Aluminum filtercake


Reviewed Battelle characterization results Evaluated strategies using combination of

subject matter expertise and bench-scale testing– Increase Energetics Neutralization

Reactors operating temperatures

Battelle performed small-apparatus testing to demonstrate proof of concept– 270, 290, and 309oF

83, 94, 98% cyanide removal efficiency

Treatment Approach / Proof of Concept

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Small-scale tests were confirmed at liter-scale with more representative mixing and pressure control– 93, 95% cyanide removal efficiencies observed at 290

and 309oF

Liter-Scale Tests

High Pressure Test Vessel

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BGCAPP selected ENR operating conditions of 300oF and 45 psig to achieve cyanide removal efficiencies on the order of 95 percent

Confirmation tests completed October 2013 using high pressure liter-scale nickel-lined vessel– No fouling observed– No enhanced corrosion

Desired Operating Condition

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High temperature treatment advantages– No new chemicals in the batch – Minimizes change to downstream SCWO recipes– Minimizes impact to downstream offgas treatment

strategies– Contact, inhalation, and ingestion hazard significantly

reduced and readily managed

Summary - Status and Path Forward

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Bench-scale proof-of-concept testing complete– High temperature treatment validated

BGCAPP is working to implement higher temperature option– New heat transfer calculations– Modification of heat delivery system required to increase

temperature from 240oF to 300oF

Minimal impact to downstream SCWO chemistry

No impact to weapons destruction baseline schedule

Summary - Status and Path Forward

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Questions


Without Treatment With Higher Temperature Treatment

Liquid(mg/L)

Air/Headspace (mg/m3)

Liquid(mg/L)

Air/Headspace (mg/m3)

Energetics Batch Hydrolyzers

600 non-detect 600 non-detect

Energetics Neutralization Reactors

350 non-detect 15 non-detect

Aluminum Precipitation Reactors

40 > 25 5 < 5

Aluminum Filtration System

20 > 5 < 1 non-detect

Anticipated Cyanide Concentrations

treatment occurs during this step

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bgcapp cyanide treatment december 11, 2013

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