ADN particles for a future missile propellants. Martin Skarstind

Transcription

1 ADN particles for a future missile propellants Martin Skarstind

2 ADN Development at FOI 2014

3 Synthesis and production of crude ADN

4 ADN Synthesis Eurenco Bofors H 2 N H N NH 2 SO 3 NH 4 HNO 3 /H 2 SO 4 <-30 o C -N NO 2 NH N NO 2 NH O -N NO 2 KOH K + -N NO 2 H 2 N N H NH 3 + FOX-12 NO 2 NO 2 NO 2 (NH 4 ) 2 SO 4 NH 4 + -N ADN NO 2

5 ADN versus FOX-12 FOX-12 Ingredient in IM grenades Ingredient in Gun propellant Air-bags in Cars Etc. ADN Ingredient in Solid propellant Ingredient in Liquid mono propellant Underwater explosives Etc. Price will fall with increased demand for either FOX-12, ADN or both

6 ADN Particles

7 Particle Processing Which sizes of ADN prills is needed? The standard Sizes in formulations of AP prills is 200µm and 20µm In our investigation of ADN/GAP formulation we saw no difference in burn rate between the different sizes

8 Prilling and crystallisation metods of ADN Prilling in inert medium Standard prilling tower American version of prill tower Cool crystallisation FOI modified prill tower

9 Prilling in inert medium Pros Prilling is rather fast Cons Crystallization is reactor size dependent Prilling in mediums like, DOA, DOS, HTPB, Paraffin etc. Medium washed away create waste of solvents Product not pure enough recrystallize during storage

10 Standard prilling tower Pros High production Low cost Cons High investment cost High tower Risk for static electricity

11 American version of prilling tower Pros Narrow particle size distribution Cons Costly recrystallization necessary Process safety risk (high temperature)

12 Cold crystalization Pros Cheap production Narrow size distribution Cons Difficult to develop a working method Biggest by-product ammonium nitrate disturbs the crystal growth Small crystals µm

13 FOI modified prill tower Pros Fast melting If ADN is ignited in the process only partial damage to the equipment Cons Spraying of an liquid throw a orifice creates socalled waterfall electricity A inert medium in the collection vessel

14 Former Spray prilling method at FOI 250g Crude ADN is melted within 15 minutes Sprayed in 1 minutes Dried for 12 minutes Mixed with 0.5% fumed silica to prevent caking

15 Spray prilling at FOI using the former method Particle density: g/cm 3 Tap density: 1.11 g/cm 3 Melting point: ~ 93 C

16 Scaled up spray prilling process OVERVIEW

17 Melting and pumping 5 l stainless steel melt reactor A water/glycol mixture heats the melt reactor and the pump 2.5 kg takes 7 min to melt Heated peristaltic pump Adjustable pump speed

18 Spraying Inert medium is sprayed on the sides Nitrogen is fed to the twin fluid nozzle Feeding lines are heat traced Spraying 3 min (200µm)

19 Drying and Control Drying is carried out in a fluidized bed dryer Drying 12 min Operation control dived up in Melting Spraying Drying Cleaning loop Particle size control Variations of the melt liquid flow Nozzle diameter Atomisation air flow

20 Prilled vs. crude ADN Free flowing powder Particle density: 1 % smaller NO 3 content <0.1% Melting point: ~ 93 ~ 92.5 C Similar sensitivity (impact, friction)) Mattias Liljedahl FOI-Bayern Chemie Meeting

21 Size distribution Batch Run No. d 10 (µm) d 50 (µm) d 90 (µm) Span FP12011:5-9 (Run 1) FP12011:5-9 (Run 2) 1 44, , ,998 1, , , ,460 1, , , ,231 1,750 Average 28, , ,166 1, , , ,059 1, , , ,493 1, , , ,650 1,710 Average 31, , ,920 1,647 ADN Size 200µm span 1,4 AP Size 200µm span 1,2 Particle Size Distribution ,01 0, Particle Size (µm) ADN prills - FP12011:5-9 (Run 1) - Average, den 8 mars :50:55 ADN prills - FP12011:5-9 (Run 2) - Average, den 8 mars :22:49 Volume (%)

22 Spray prilled ADN ~ 200 µm ~ 60 µm

23 Estimated future price for prilled ADN The estimated production price for prilled ADN in the 40 ton scale will be about 80Eu per Kg. The estimated production price for prilled ADN in the 400 ton scale will be about 64 Eu per Kg. Particle size µm

24 Ongoing work Adjustments to the spray nozzles Increase the density of the prills Produce 20µm prills or less

25 Co-prilling ADN with Fox-12 vary the amount of FOX-12 versus ADN 10-40% FOX-12 dissolved in ADN melt Less sensitivity were obtained Burning characteristics?

26 Grinding/milling Prilled ADN used in the air jet mill Different feed pressures 100 g takes 15 sek

27 Grinding/milling Density g/cm 3 Particle size 15-20µm Irregular in shape

28 Estimated future price for grinded ADN The price for Jet milled ADN in the future has been estimated at 40 tons per year to be around 57Eu per Kg. The price for Jet milled ADN in the future has been estimated at 400 tons per year to be around 54Eu per Kg.

29 Taking into account the last couple of year s technological progress concerning the development of a ADN based propellants The cost structure of ADN can be over come when it is produced in reasonable production scale ADN prills are readily available in different sizes ADN - can seriously be considered in a propellant for a future missile systems