Reaction Balance of Thermal and Catalytic Decomposition of Nitrogen-Based Ionic Monopropellant

Reaction balance of thermal and catalytic

decomposition of nitrogen-based ionic

monopropellants

K. Farhat*, Y. Batonneau, C. Kappenstein

LACCO, Université de Poitiers (France)

And M. Ford

ESA-ESTEC, Keplerlaan, 2200 AG Noordwijk ZH, the NetherlandsESA-ESTEC, Keplerlaan, 2200 AG Noordwijk ZH, the Netherlands

� INTRODUCTION

• Energetic ionic liquids

• Previous results at LACCO

� EXPERIMENTAL PART

• HAN preparations and characterization

• Flow reactor

OUTLINE

HEM – Arcachon, October, 1-3, 2007 2/21

• Flow reactor

�RESULTS

• HAN – thermal and catalytic decomposition

• ADN - thermal and catalytic decomposition

• AN - thermal and catalytic decomposition

� CONCLUSIONS / PERSPECTIVES

Introduction Experimental Part Results Conclusions/Perspectives

Energetic ionic liquids (oxidizer + fuel + solvent)

Oxidizer Oxygen balance Formula Density /g.cm-3 Solubility, 20°°°°C

HAN 33.3 % [NH3OH]+[NO3]

- 1.84 95 %

ADN 25.8 % [NH4]+[N(NO2)2]

- 1.81 78 %

AN 20.0 % [NH4]+[NO3]

- 1.73 56 %

HNF 13.1 % [N2H5]+[C(NO2)3]

- 1.91 53 %


HNF 13.1 % [N2H5]+[C(NO2)3]

- 1.91 53 %

HN 8.4 % [N2H5]+[NO3]

- 1.69 -

• Support resistant at high temperature (1400 °C)

• Active phase�� propellant decomposition at low temperature

• Good selectivity in thermodynamic products

fuel association appropriate catalyst


Previous Results at LACCO

DTA-TGABatch Reactor

Best catalyst:Pt/Al2O3Si – active at room temperature

R. Eloirdi, L. Courteoux, D. Amariei,

thesis, University of Poitiers, 2001, 2004, 2006

- fast exothermic decomposition

- pressure increase lower than expected for thermodynamic products:

HAN-water decomposition:


thermodynamic products:

NH3OHNO3(aq) = O2(g) + N2(g) + 2 H2O(l)

These methods are unable to determine the nature of decomposition products

need to establish the mass balance of the decomposition of HAN-water solutions


NH2OH (aq) + HNO3 (aq) � [NH3OH]+[NO3]-(59wt.-%) (aq)

HAN synthesis

Evaporation

87 wt-% HAN

10

12

HNO3 65%


2

4

6

8

0 5 10 15 20 25 30 35

pHVolume de HNO3 (mL)

NH2OH 50%

T < 4 °C

Ice

pH

stirrer


HAN characterization

- Acid-base titration - RAMAN spectroscopy

1.5 104

2 104

2.5 104

3 104

1051

Inte

nsit

y / u

.a

8

10

12

14

NO3-


0

5000

1 104

1.5 104

0 500 1000 1500 2000 2500 3000 3500 4000

720

1012

31472992

27161417

1606

1183 3488

Raman shift / cm -1 In

tens

ity

/ u.a

2

4

6

8

0 5 10 15 20 25

pH

Volume (NaOH 1 mol/L) / mL

NH3OH+

N-OH

NO3-


Analysis of the decomposition products: flow reactor

OvenThermocouple

Vector gas flow

controller

Electronic flow controller

He vector gas

Pressure gauge

Quartz reactor

Septum or gascalibration


Identification of gaseous decomposition products: N2, O2, NO, N2O, NO2

Y. Batonneau, L. Courthéoux, P. Esteves, L. Pirault-Roy, S. Rossignol, C. Kappenstein, N. Pillet, AIAA Papers, (2004) 3835.

Mass spectrometer (MS) (gas products)Extractor

He vector gas

Silica column cold trap ( RAMAN spectroscopy and acid-base titration)


Analysis of the decomposition products: flow reactor

Catalyst mass: 160 mg

Propellant volume: 100 µµµµL Reactor pre-heated at a given T


Catalyst used during this study:Pt/Al2O3Si –powder (laboratory)

essentially Developed for HAN decomposition


HAN – Thermal decomposition at 220 °C

4

6

8

10

12

14

Gas

per

cent

age

/ %

N2

N2ON O

2*100O

2*10

N O

Gaseous decomposition products (MS results)


0

2

4

200 300 400 500 600 700 800 900

Gas

per

cent

age

/ %

T im e / s

222

Experimental estimationN2 : NO : N2O = 3 : 1 : 1

�� PRIMARYN2 (major) NO (medium)NO2(traces)

O2 (traces) – air impurities

�� SECONDARYN2O (medium)NO2 (traces)

Rel

ativ

e in

tens

ity

Trapped solution

RAMAN spectroscopy


HAN (87 wt.-%) – Thermal decomposition at 220 °C

NO3- (1050 cm-1)

N-OH (1012 cm-1)

NO3- (720 cm-1)

Analysis of trapped productsAcid-base titration

6

8

10

12

14

pH

H+


Raman shift / cm-1

HAN 86.6 wt.-%

Trapped solution

HNO3 39 wt.-%

0

2

4

0 2 4 6 8 10Volume (NaOH 1 mol/L) / mL

�Total HAN decomposition:- Absence of the peak at 1012 cm-1 in collected solution- One acid-base equivalent point

Same results for catalytic decomposition

� The collected solution contains

nitric acid ( HNO3 , 42 wt.-%).

�Molar ratio HNO3 / HANdec ~ 0.4 to 0.5

Formation of primary N2 and NO: redox reaction between [NH3OH]+ and NO3

- ions

6 NH3OHNO3(aq) = 3 N2(g) + 2 NO(g) + 10 H2O(g) + 4 HNO3(g) (1)

6 NH3OHNO3(aq) = 2 N2(g) + 2 NH4NO3(s) + 6 H2O(g) + 4 HNO3(g) (2)

HAN – Thermal and catalytic decomposition –Proposal for the reaction balance

N2 excess and NH4NO3 formation: disproportionation reaction of [NH3OH]+ cation



Decomposition of NH4NO3: formation of N2O

2 NH4NO3(s) = 2 N2O(g) + 4 H2O(g) (3)

�� Complete balanced equation - linear combination: (1) + 1.5x(4)

15 NH3OHNO3(aq) = 6 N2(g) + 2 NO(g) + 3 N2O(g) + 25 H2O(g) + 10 HNO3(g)

6 NH3OHNO3(aq) = 2 N2(g) + 2 N2O(s) + 10 H2O(g) + 4 HNO3(g) (4)

Combining equations (2) and (3)


Gaseous decomposition products

10

15

20

Gas

per

cent

age

/ %

N2

NO*10

ADN (50 wt.-%)– Thermal decomposition at 320 °C


0

5

1000 1100 1200 1300 1400 1500 1600 1700 1800

Gas

per

cent

age

/ %

Time / s

N2O

NO2*100O

2*10

�� PRIMARYN2 (major) O2 (traces) – air

impurities

�� SECONDARYN2O (medium)NO2 (traces)NO (traces)

8

10

12

pH


ADN (50 wt.-%)– Thermal decomposition at 320 °CAnalysis of trapped products

NH4+

Collected solution

Reactor walls solidRel

ativ

e in

tens

ity NO2

- (828 cm -1)NO2

- (1330 cm -1)

NO3- (720 cm -1)

NO3- (1048 cm -1)

Acid-base titrationRAMAN spectroscopy


4

6

0 0.5 1 1.5Volume (NaOH 1 mol/L) / mLVolume (NaOH 1 mol/L) / mL

Reactor walls solid

AN solid

ADN solid

Rel

ativ

e in

tens

ity

Raman shift / cm-1

� Total ADN decomposition

2 NH4N(NO2)2 (aq) �� NH4NO3(aq) + 2 N2(g) +N2O(g) + 2 H2O(l) + O2(g)

� The collected solution contains ammonium nitrate


Gaseous decomposition products

ADN (50 wt.-%)– Catalytic decomposition at 250 °C

10

15

20

Gas

per

cent

age

/ %

N2

O2 NO*10


�Decomposition in 2 steps:

0

5

1000 1200 1400 1600 1800 2000

Gas

per

cent

age

/ %

Time / s

N2O

NO2*100

�Second: major products: N2, N2O, NO and NO2

�First: major products: N2 and O2

Rel

ativ

e in

tens

ity

Collected solution


ADN (50 wt.-%)– Catalytic decomposition at 250 °CAnalysis of trapped products

8

10

12

pH

NH4+

NO3- (720 cm -1)

NO3- (1048 cm -1)NO2

- (1330 cm -1)

NO2- (828 cm -1)

RAMAN spectroscopy Acid-base titration


Rel

ativ

e in

tens

ity

Raman shift / cm-1

Collected solution

AN solid

ADN solid

HNO3 39 wt.-%

0

2

4

6

0 0.5 1 1.5 2 2.5 3Volume (NaOH 1 mol/L) / mL

H+

�The collected solution contains: NH4+, H+, NO3

- and NO2-

ADN – Thermal and catalytic decomposition –Proposal for reaction balance


5

10

15

20

Gas

per

cent

age

/ %

N2

NO2*100

O2 NO*10


NH4N(NO2)2 (aq) �� 2N2(g) + 2H2O(g) + O2(g)

6NH4N(NO2)2 (aq) �� 4N2(g) + 3H2O(g) + 3N2O(g) + 4NH4NO3(g) + 2HNO3(g)

0

5

1000 1200 1400 1600 1800 2000

Gas

per

cent

age

/ %

Time / s

N2O

NO2*100

NH4NO3 ��N2O(g) + 2 H2O(g)

NH4NO3 ��NH3(g) + HNO3(g)

0.4

0.6

0.8

1

Gas

per

cent

age

/ % N2

N2O

NO *100


AN (56 wt.-%)– Thermal decomposition at 450 °C

8

10

12

14

pH

Acid-base titration of trapped solution Gaseous decomposition products

NH4+


0

0.2

0.4

3200 3300 3400 3500 3600 3700 3800 3900 4000

Gas

per

cent

age

/ %

Time / s

NO2*100

O2*10 NO*10

4

6

8

0 2 4 6 8 10Volume (NaOH 1 mol/L) / mL

Very slight decomposition of NH4NO3 in these conditions

NH4NO3(l,s)�� NH3(g) + HNO3(g) �� NH4NO3(g) �� NH4NO3(l) �� NH4NO3(s)


AN (56 wt.-%)– Catalytic decomposition at 320 °C

10

15

20

25

Gas

per

cent

age

/ %

N2

N2O*10O

2*10

NO*10

Analysis of trapped products Gaseous decomposition products

Presence of characteristic vibrations peaks of NO3

-

RAMAN spectroscopy:

Acid-base titration


0

5

1500 1600 1700 1800 1900 2000 2100 2200

Gas

per

cent

age

/ %

Time / s

2NO

2*100

NH4NO3(l,s)�� NH3(g) + HNO3(g) �� NH4NO3(g) �� NH4NO3(l) �� NH4NO3(s)

Partiel AN decomposition

The trapped solution contains NH4

+

NH4NO3 ��N2(g) + 2 H2O(l) + 0.5 O2(g)

NH4NO3 ��N2O(g) + 2 H2O(l)


Conclusions

1) Thermal and catalytic decomposition of HAN - water mixtures

� primary products: major N2 and HNO3, medium NO

� secondary products: medium N2O and traces NO2

2) Thermal decomposition of ADN - water mixtures

� primary products: major N2 and NH4NO3

� secondary products: medium N2O and NO, traces NO2

3) Catalytic decomposition of ADN - water mixtures


3) Catalytic decomposition of ADN - water mixtures

Decomposition in 2 steps:

� First: primary products: major N2 and O2

� Second: primary products: major N2 and HNO3

secondary products: medium N2O, medium NO and traces NO2

4) No thermal decomposition of AN-water mixtures

5) Catalytic decomposition of AN - water mixtures

�primary products: major N2 and medium NO

�secondary products: medium N2O and traces NO2


� Find an adequate catalyst to decompose selectively HAN-water mixture in thermodynamic products

� Find a good catalyst to decompose ADN-water mixture in one step (first step)

Perspectives


� Decomposition study of ammonium nitrate

� Thermal and catalytic decomposition study of HNF and HN

Acknowledgements


Reaction Balance of Thermal and Catalytic Decomposition of Nitrogen-Based Ionic Monopropellant

Documents

Transcript of Reaction Balance of Thermal and Catalytic Decomposition of Nitrogen-Based Ionic Monopropellant