Newly Developed Technology for Ecological Demilitarization of

3 Newly

D e v e l o p e d T e c h n o l o g y for Ecological

D e m i l i t a r i z a t i o n of

Munitions

F. H. CRIST

Downloaded by UNIV OF SYDNEY on April 3, 2018 | https://pubs.acs.org Publication Date: April 6, 1979 | doi: 10.1021/bk-1979-0096.ch003

Ammunition Equipment Office, Tooele Army Depot, Tooele, UT 84074

The Army, in its role as storekeeper of munitions for a l l DoD services, has a continuing requirement to demilitarize unserviceable or obsolete munitions. H i s t o r i c a l l y , demilitarization of munitions was accomplished by such expedients as sea dump or open a i r destruction. In 1970, the President signed Executive Order 11507 (later superseded by Executive Order 11752 dated 17 December 1973) directing that Federal Agencies set the example in abating pollution of the environment. This paper addresses some of the engineering efforts being expended to develop ecologically clean demilitarization technology that is safe for personnel handling this dangerous commodity. The candidate technology must also be affordable within the austere funding available for this important, but nevertheless, lower p r i o r i t y program that contributes relatively little to our defense posture. The demilitarization workload includes small arms ammunition, small to large caliber a r t i l l e r y ammunition, mines, mortar ammunition, rockets, bombs and myriad quantities of components that are used in the assembly of conventional munitions. Chemical munitions have received more intensified engineering and s c i e n t i f i c effort to insure absolute safety of operators and positive retention of effluents generated by disposal operations. Figure 1 shows a cross section of a rotary k i l n type deactivation furnace developed to demilitarize small arms ammunition and various munition components. This equipment was designed to either burn or detonate the energetic material as i t is moved by the helix flight from the cool feed end through the constantly increasing temperature of the 20-foot long retort. The deactivation furnace has proven to be an extremely cost effective system with all or much of the operating expense defrayed by the salvage value of decontaminated metals recovered by the process. Unfortunately, the high process feed rate generated large amounts of pollution to the atmosphere, A very high p r i o r i t y was therefore assigned to the development of emission controls for this process. This chapter not subject to U.S. copyright. Published 1979 American Chemical Society

Scott; Toxic Chemical and Explosives Facilities ACS Symposium Series; American Chemical Society: Washington, DC, 1979.

Scott; Toxic Chemical and Explosives Facilities ACS Symposium Series; American Chemical Society: Washington, DC, 1979. Figure 1.

Furnace deactivation



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E a r l y i n the emission c o n t r o l development program, i t was recognized that the burning o f myriad types o f munitions and munition components could generate a horrendous number of chemi c a l compounds i n the e f f l u e n t produced by the process. A thermochemistry computer program, developed at Edwards A i r Force Base to d e s c r i b e the burning o f rocket motors, was m o d i f i e d and implemented to p r e d i c t products to be found i n the e f f l u e n t when burning d i f f e r e n t munition items. T h i s program, through constant improvement and c o r r e l a t i o n with a c t u a l stack sampling during operations, proved to be extremely b e n e f i c i a l i n o p t i m i z i n g the furnace o p e r a t i o n to minimize p o l l u t a n t s o f concern. A f t e r n e a r l y one year o f t e s t burning with stack sampling accomplished by both p r i v a t e c o n t r a c t o r s and Government personnel, i t was concluded that only p a r t i c u l a t e emission c o n t r o l was r e q u i r e d to f u l l y comply with a l l EPA and S t a t e standards. The c o n t r o l equipment s e l e c t e d c o n s i s t e d o f a cyclone separator intended to remove large combustible p a r t i c u l a t e s and sparks, spark a r r e s t o r screen and a standard bag house f o r removal o f f i n e p a r t i c l e s . The i n i t i a l success o f t h i s system was marred by infrequent bag house f i r e s . An i n t e n s i v e engineering i n v e s t i g a t i o n of these f i r e s d i s c l o s e d that the instrumentation used i n p r e f a t o r y and developmental t e s t i n g was incapable of r e c o g n i z i n g and responding to short d u r a t i o n , high temperature, exhaust gas excursions. The system was modified to permit a g r e a t e r q u a n t i t y o f d i l u t i o n a i r and a c o n t r o l system more responsive to short d u r a t i o n , high temperature surges. T h i s m o d i f i e d system has proven to be extremely e f f e c t i v e i n abating p o l l u t i o n o f the environment with no f i r e s i n the bag house. Most noteworthy i s the f a c t that no a d d i t i o n a l operators were r e q u i r e d and only one 25 hp motor was added to the t o t a l system consumption of energy. The system was designed so that a d d i t i o n a l c o n t r o l such as N0 can be provided i f r e q u i r e d i n the f u t u r e . X

A program to expand the a p p l i c a t i o n o f the d e a c t i v a t i o n furnace f o r items with g r e a t e r amounts o f e n e r g e t i c m a t e r i a l was undertaken simultaneously with the development of emission cont r o l equipment. Army engineers p o s t u l a t e d and proved by t e s t s that munitions could be degraded to expose e n e r g e t i c m a t e r i a l s so that these m a t e r i a l s would burn r a t h e r than detonate when introduced i n t o the d e a c t i v a t i o n furnace. Figure 2 d e p i c t s l i v e , high e x p l o s i v e , hand grenades degraded by the a p p l i c a t i o n of a small vent punched i n t o i t s s i d e w a l l and munitions i n e r t e d by punching and p r o c e s s i n g them through the d e a c t i v a t i o n furnace. Munitions c o n t a i n i n g i n excess of 1/2 pound of high e x p l o s i v e have been s u c c e s s f u l l y sheared and burned i n the d e a c t i v a t i o n furnace. Avoiding the cost o f r e v e r s i n g the manufacturing process by r e c o v e r i n g salvage metals that would have been l o s t i n the open a i r d e s t r u c t i o n o f these items provide major monetary b e n e f i t s o f t h i s new technology. Shearing equipment, capable of matching the grenade burning r a t e of 22 rounds per minute, i s now being completed to permit f u l l s c a l e p r o d u c t i o n


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Figure 2.

M26 grenades, sheared and burned



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t e s t i n g and operation. Some time back, the Ammunition Equipment O f f i c e was tasked to develop a safe and e c o l o g i c a l l y c l e a n d e m i l i t a r i z a t i o n system f o r unserviceable nerve gas f i l l e d chemical munitions. Following the time-proven s a f e t y concept of having the l e a s t q u a n t i t y o f explosive f i l l e d munitions and the l e a s t number of operators present at the operation f o r the s h o r t e s t p o s s i b l e time, Ammun i t i o n Equipment O f f i c e designed and developed the system shown at Figure 3. The machine developed to d e m i l i t a r i z e the munitions i s housed i n a very s u b s t a n t i a l e x p l o s i v e containment v e s s e l . T h i s v e s s e l was designed and has proven by dynamic t e s t s u i t a b l e f o r c o n t a i n i n g a l l fragments, gases and overpressures produced by a munition f u n c t i o n that could occur during the d e m i l i t a r i z a t i o n process. The equipment i s designed to be monitored and t o t a l l y c o n t r o l l e d by computer. A manual o v e r r i d e of some f u n c t i o n s f a c i l i t a t e d by c l o s e d c i r c u i t TV has a l s o been provided. The only entry by personnel i n t o the e x p l o s i v e containment c u b i c l e w i l l be f o r maintenance o f the system. Work done w i t h i n the explosive containment c u b i c l e i s shown i n Figure 4. An M55 rocket contained i n i t s shipping container i s r e c e i v e d on the i n s i d e of the e x p l o s i v e containment c u b i c l e . A l l openings of the c u b i c l e are c l o s e d , sealed and locked before the rocket i s punched and drained o f l i q u i d nerve agent. A f t e r removal and t r a n s f e r of the nerve agent by appropriate p i p i n g , the rocket, s t i l l i n i t s c o n t a i n e r , i s clamped i n the machine, submerged under decon s o l u t i o n and severed i n t o seven p i e c e s by saws with six s p e c i a l c i r c u l a r blades. Major advantages o f t h i s technology development are the avoidance of a l l unpacking and disassembly operations, the e l i m i n a t i o n of personnel from the immediate demili t a r i z a t i o n area and the r e l a t i v e l y short (approximately f o u r minutes) c y c l e time. The severed s e c t i o n s produced by t h i s system are i n d i v i d u a l l y fed i n t o the d e a c t i v a t i o n furnace where burning of the e n e r g e t i c m a t e r i a l and intense heating by the burner w i t h i n the r e t o r t guarantee t o t a l decontamination o f the residue. The technology developed f o r d e m i l i t a r i z a t i o n o f nerve agent f i l l e d rocket munitions has a l s o been e x p l o i t e d i n the d e m i l i t a r i z a t i o n of conventional a r t i l l e r y p r o j e c t i l e s . P r o j e c t i l e s are severed i n s u i t a b l e length p i e c e s to permit burning of the unconfined e n e r g e t i c m a t e r i a l i n the d e a c t i v a t i o n furnace. More importantly, Ammunition Equipment O f f i c e engineers have p o s t u l a t e d that 5 p s i steam heating of the e x t e r i o r casing o f sectioned p r o j e c t i l e s would melt the i n t e r f a c e m a t e r i a l between the s t e e l s i d e w a l l and the explosive charge t o permit the e x p l o s i v e charge to s l i p from the c a s i n g . F i g u r e 5 d e p i c t s sample TNT and Composition B p r o j e c t i l e s that were severed and steam heated f o r removal of the e x p l o s i v e charges. Explosive charges thus removed have been analyzed and found to be e n t i r e l y s u i t a b l e f o r r e c y c l i n g i n the manufacture of new munitions. An explosive washout process was developed s e v e r a l years




O



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Figure 4.

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M55 rocket before and after sectioning

Figure 5. TNT and composition B severed projectiles before and after melt out


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ago f o r d e m i l i t a r i z a t i o n o f l a r g e c a l i b e r a r t i l l e r y p r o j e c t i l e s and bombs that could not be open a i r detonated at depots i n c l o s e p r o x i m i t y to p o p u l a t i o n c e n t e r s . In the washout process, hot water at high pressure melted and h y d r a u l i c a l l y eroded b i n a r y e x p l o s i v e from the i n t e r i o r o f l a r g e c a l i b e r p r o j e c t i l e s and bombs. The e x p l o s i v e was then recovered through a p e l l e t i n g process f o r s a l e as a b l a s t i n g agent. Contamination picked up i n the washout process precluded r e c y c l i n g o f the e x p l o s i v e f o r f u r t h e r m i l i t a r y use. Treatment f a c i l i t i e s were a l s o provided to optimize the r e c y c l i n g o f waters used i n the process. U n f o r t u n a t e l y , the system uses c o n s i d e r a b l e energy f o r the accomplishment o f i t s purpose. Recent, more s t r i n g e n t , regul a t i o n o f the q u a l i t y o f l i q u i d waste e f f l u e n t would mandate a considerable investment t o upgrade the p o l l u t i o n c o n t r o l equipment. A new method f o r removal o f e x p l o s i v e from bombs and l a r g e c a l i b e r p r o j e c t i l e s was s o r e l y needed. The use o f microwave energy was one o f the candidate systems evaluated by Ammunition Equipment O f f i c e engineers. A small 5 kw microwave u n i t was rented and used f o r a s e r i e s o f melting t e s t s . The t e s t proved the v a l i d i t y o f the system with two major bonuses: (1) Less than 20 kwhr o f e l e c t r i c energy was consumed i n the removal of e x p l o s i v e s from a 750 pound bomb as compared t o over 975 kwhr of equipment energy consumed by the washout process and (2) no l i q u i d or gaseous e f f l u e n t were produced by the microwave melt out o f the e x p l o s i v e from the bombs. A production f a c i l i t y that w i l l c o r r e c t some problems encountered during t e s t i n g and o p t i mize the s a t i s f a c t o r y t e s t r e s u l t s i s now being developed. Figure 6 d e p i c t s the u l t i m a t e f a c i l i t y v i s u a l i z e d by the Ammun i t i o n Equipment O f f i c e engineers. It has been common p r a c t i c e over the years to decontaminate downloaded ammunition p a r t s or u n s e r v i c e a b l e machinery potent i a l l y contaminated with e x p l o s i v e s by open a i r burning. Both the Clean A i r Act and S u b t i t l e C under the Resource Recovery Act preclude c o n t i n u a t i o n o f t h i s procedure. A s p e c i a l l y designed f l a s h i n g furnace was procured and has been very s u c c e s s f u l l y t e s t e d f o r the accomplishment o f t h i s work. The furnace was designed with workload c a p a c i t y adequate t o handle the products of s e v e r a l d i f f e r e n t d e m i l i t a r i z a t i o n methods. The e f f l u e n t s generated by operation o f t h i s equipment are very s i m i l a r t o those generated by the d e a c t i v a t i o n furnace, t h e r e f o r e , i t can share u t i l i z a t i o n o f the same p o l l u t i o n c o n t r o l system. When operation o f both the f l a s h i n g furnace and the d e a c t i v a t i o n furnace i s r e q u i r e d , f l a s h i n g furnace operation can be performed during an o f f s h i f t i f necessary. White phosphorus f i l l e d munitions are a major item i n the current Army d e m i l i t a r i z a t i o n inventory. Ammunition Equipment O f f i c e engineers are developing methods to punch a s i z e d hole i n t o the white phosphorus f i l l e d munition t o c o n t r o l the r a t e at which burning occurs when the munition i s processed through the d e a c t i v a t i o n furnace. By c o n t r o l l i n g the burning r a t e , the



Figure 6.

Facility concept for meltout and recovery of explosive by microwave energy


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Scott; Toxic Chemical and Explosives Facilities ACS Symposium Series; American Chemical Society: Washington, DC, 1979. Figure 7.

White phosphorus munitions disposal plant


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Industrial robot


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AND EXPLOSIVES FACILITIES

e f f l u e n t can be processed through a hydrator and v e n t u r i scrubber f o r the production o f r e l a t i v e l y low grade phosphoric a c i d . T h i s process would t o t a l l y e l i m i n a t e the need f o r open a i r burning o f t h i s item and i s expected to net a s l i g h t p r o f i t over operating expenses. Figure 7 shows the Ammunition Equipment O f f i c e engineer's concept f o r the f a c i l i t y . The d e m i l i t a r i z a t i o n o f munitions introduces some unusual hazards t o operators performing the v a r i o u s t a s k s . Considerable e f f o r t has been expended t o separate the operator from the immed i a t e v i c i n i t y where the munition i s being processed. Figure 8 d e p i c t s an i n d u s t r i a l robot configured by Ammunition Equipment O f f i c e engineers s p e c i f i c a l l y f o r the accomplishment o f v a r i o u s ammunition handling operations. The robot i s computer c o n t r o l l e d with f o u r separate computer programs, each capable o f executing 128 d i s c r e t e steps. Since procurement o f the robot, a system u t i l i z i n g very s e n s i t i v e p r o x i m i t y sensors has been developed t o recognize the geometry o f a p r o j e c t i l e at the pickup p o i n t and determine whether i t i s o r i e n t e d c o r r e c t l y f o r placement i n a machine f o r disassembly. I f orientation i s incorrect, binary s i g n a l s from the p r o x i m i t y sensors t r i g g e r a subroutine of the robot program to r o t a t e the p r o j e c t i l e a f t e r pickup t o c o r r e c t i t s r e l a t i o n s h i p with the disassembly machine. Many d i f f e r e n t a p p l i c a t i o n s o f the robot have proven i t t o be extremely v e r s a t i l e and r e l i a b l e f o r the performance of r e p e t i t i v e operations. The robot not only has the c a p a b i l i t y o f handling munitions t o and from disassembly equipment, but a l s o monitors and c o n t r o l s the equipment. Most o f the d e m i l i t a r i z a t i o n workload accommodated by new processes discussed i n t h i s paper i n c l u d e munitions developed during the Korean c o n f l i c t . Many newer munitions now i n storage are more s o p h i s t i c a t e d and complex i n t h e i r assembly. Development of s a f e , cost e f f e c t i v e and e c o l o g i c a l l y c l e a n d e m i l i t a r i z a t i o n c a p a b i l i t y f o r these items w i l l be a keen challenge t o the m i l i t a r y and c i v i l i a n engineering and s c i e n t i f i c community i n v o l v e d i n t h i s work. RECEIVED November 22,

1978.


Newly Developed Technology for Ecological Demilitarization of

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