KINETIC MECHANISM INVESTIGATION ON NOx REMOVAL WITH

HYDRAZINE HYDRATE AT MODERATE TO HIGH TEMPERATURES

HONG Liu1, Yin Lijie

1, CHEN De-zhen

1, WANG Du

2

1.Thermal & Environmental Engineering Institute, Tongji University, Shanghai, China;

2. Institute of Energy & Environment Engineering, Shanghai University of Electric Power, Shanghai,

China

Introduction

Selective non-catalytic reduction (SNCR) De-NOx technology has been used to reduce

nitrogen oxides (NOx) emission from flue gas for nearly 30 years [1]

. In the SNCR process, gaseous or

solution reagent (ammonia, urea etc.) is injected into the hot exhaust gases of stationary combustion

systems in the presence of certain level of oxygen, initiating a sequence of reactions that convert NOx

to molecular nitrogen (N2) [2]

. But the SNCR De-NOx process works only in a narrow temperature

window roughly between 1100K and 1400K. In practice combustion systems, NOx reduction is often

desirable at lower temperatures [3]

. Hydrazine hydrate (N2H4·H2O) is a kind of intensive reducer,

which is widely used as rocket propellant, pesticide material and deoxidizer of boiler etc. The

N2H4-NO-O2 reaction has been studied by Azuhata et al. on a laboratory scale, the result showed that

NO was reduced to N2 and H2O by N2H4 in the temperature range of 773-873K and the presence of

O2 prohibited the reduction of NOx [4]

. J. B. Lee et al. [5]

tested the NOx reduction with hydrazine in a

pilot-scale reactor, and they founded that hydrazine had an effective de-NOx effect in temperature

range of 800-950K, which was about 300K lower than that of ammonia. However, little information

on complete kinetics mechanism of hydrazine-based NOx reduction is reported till now. Zhang et al.[6,

7] proposed the rough kinetics mechanism of NOx reduction with hydrazine and founded that the

effective temperature range is 763-928K by experiment, but the NO reduction predicted by

calculation is much greater than that of measured by experiments.

In 1975, Lyon et al. first discovered SNCR process and applied for the relevant patent [8, 9]

;

subsequently, many detailed kinetics models were presented. In 1989, a so-called Miller & Bowman

(M&B) model was summarized, which includes 53 species of reactants and 251 reactions, covering

the reactions between NH3 and NO in SNCR process and the NO formation reactions in combustion

of hydrocarbons. M&B model was later modified by Miller and Glarborg in 1999 [10]

to describe the

whole SNCR process between NH3 and NO more precisely. However the kinetics mechanism of

reactions of hydrazine and NO should be different. Konnov et al. [11]

proposed a decomposition

mechanism of hydrazine in inert gases, including 11 species and 51 elementary reactions. Reaction

mechanisms of hydrazine decomposition and oxidation have also been proposed [12, 13]

, however most

of the rate coefficients in the model were approximately estimated. A more detailed kinetics

mechanism for hydrazine-based SNCR process was proposed and verified by comparison with the

experimental results in our previous researches

[14], and the model provided 24 species and 113

elementary reactions, matching well with experimental data in respect of NO reduction trends versus

temperature. But there is distinct gap between the computational results and the experimental data,

which was caused by the fact that the operation condition of the experimental reactor was far from

perfectly stirred reactor (PSR) that was adopted in the simulation model.

In this study, a revised kinetic model for the N2H4-NO-O2 reaction is proposed to verify the

kinetics model, the computational results were compared with the experimental results; and the

practical operation conditions of the experimental reactor was involved in the computational

simulation process.

Experiment

Experiment set-up

The experimental system of NOx reduction by N2H4·H2O is shown in Fig 1. The reactor wall is

insulated to keep a nearly stable temperature distribution in the reactor. The total flow rate of the flue

gas varies from 62.8 to 98.2 Nm3h

-1. N2H4·H2O solution is sprayed into the stream of combustion

products through two atomizing nozzles installed in a pilot-scale pipe flow reactor. In order to

measure the dosage of de-NOx reagent, normalized stoichiometric ratio (NSR) is defined as:

x

x

NOandreagentbetweenratiomoletricstoichiome

NOandreagentbetweenratiomoleactualNSR (1)

Three thermocouples are installed at 1m length intervals along the reactor axis to measure the

temperature of the flue gas in the reactor. The flue gas contained about 150ppm of CO, 10% of H2O

and 3% of CO2. N2 is added into the chamber of the furnace in order to regulate the O2 pressure of

the flue gas, O2 content of the flue gas descends with the increase of temperature and varies from

9.8% at 1271K to 15.8% around 780K. In this temperature range, more than 90% of NOx exists in

the form of NO [17]

, so NO was used to replace NOx here. The inlet concentration of NO varies from

320 to 580ppmv and increases with the increase of temperature. During the experiments, the NSR

value varies from 1.5 to 4.0 considering the incomplete contact between flue gas and de-NOx reagent.

A KM9106 type gas analyzer (Kane, UK) is used to measure concentrations of NO, NO2 and O2 etc.

A PGM-7800 multiple gas analyzer (RAE, USA) is used to monitor concentration of NH3 to check

the “ammonia slip” and a PGM-7240 VOC analyzer (RAE, USA) is used to monitor N2H4 slip.

Figure 1. Schematic diagram of SNCR experimental set-up

Experiment results and discussion

The de-NO efficiency η is calculated by

in

out

NO

NO

][

][1 (2)

Where [NO]in and [NO]out are volume fractions of NO at inlet and outlet respectively.

Fig 2 shows the de-NO efficiency versus temperatures when NSR=4.0. With the increase of

temperature, the de-NO efficiency represents bimodal characteristics, where the lower temperature

window is from 820K to 960K, and the higher temperature window is from 1260K to 1330K. Fig 2

also shows the influence of NO concentration on the de-NO efficiency, it’s found that when the NO

concentration increases from 360ppmv to 811ppmv, the temperature windows changes little. This

means that the NO concentration has little effect on the de-NO efficiency.

Initial condition: NOini=360~811ppmv (900K), NSR=4.0,

O2 content: 9.8 %( higher temperature) ~15.8 %( lower temperature)

Figure 2. de-NO efficiency of SNCR experiments by hydrazine

Simulation

Simulation model

The kinetics mechanism of SNCR reaction by hydrazine proposed in this research is listed in

Appendix. Based on the previous kinetics mode [14]，a new reaction R114 is brought into the

mechanism considering the effect of HONO during the de-NO process. Besides, the rate coefficients

of three reactions R32, R33 and R58 are applied according to the research of Diau and Glarborg et al. [15, 16]

. The revised reactions and their rate coefficients are listed in Table 1.

Table 1. Revised kinetic parameters of elementary reactions

Reaction A(cm3, moles, sec) n E(cal/mole)

R32. NH2+OH = NH+H2O 5.0E11 0.50 1986

R33. NH2+NO = NNH+OH 8.9E12 -0.35 0

R58. NH2+O2 = HNO+OH 2.0E12 0.00 14893

R114. NO+OH+M = HONO+M 5.1E23 -2.51 -68

The general form of governing equation is defined as

Sgraddivudiv (3)

where represents different variables in different equations, is the density, kg·m-3

,

is the diffusion coefficient and S is the source term. The concrete forms of , and S in different

governing equations are listed in Table 2. Standard k model is applied to describe the flow field

and temperature distribution of the gas in the reactor, and P-1 model is adopted to simulate the

radiation heat transfer of flue gas.

Table 2. Governing equations

Equation S

Continuity 1 0 0

X-momentum u teff

x

w

zx

v

yx

u

xx

peffeffeff

Y-momentum v teff

y

w

zy

v

yy

u

xy

peffeffeff

Z-momentum w teff

z

w

zz

v

yz

u

xz

peffeffeff

Turbulent kinetic

energy k

k

t

kG

Rate of viscous

dissipation

t

21 CGC

kk

Energy T T

t

Pr Se

Species nY

t

tn

ScD

Sn

The constants in the governing equations are as follows:

3.1,0.1,09.0,92.1,44.1 21 kCCC (4)

The parameter Se in energy conservation equation is the source term resulted from reaction:

n

nne hwS (5)

Where wn is the nth reaction rate, andΔ hn is the enthalpy change of the nth reaction.

The reaction rate of the nth elementary reaction can be calculated by:

rnrn kCw (6)

RTETAk rrrnr exp

(7)

where Cr is the molar concentration of reactants, mole·m-3

, is the reaction exponent, Ar is

the pre-exponential factor, cm3·mole

-1·s-1

, β r is the temperature exponent, and Er is the activation

energy of reaction, cale·mole-1

, R is the gas constant. Detailed values of the above-mentioned

parameters are listed in Appendix.

In order to consider the effect of flow of flue gas on the NO reduction, the chemical kinetic

mechanism and thermodynamic data are specified by PSR model in CHEMKIN to form a file firstly,

and then the file is imported into FLUENT. The temperatures of reactor and reactants are constant

during the de-NO process, and the mixing process of reactants is neglected. The de-NO efficiency is

calculated by comparing the area-weighted average concentrations of NO at different positions of

reactor (inlet & outlet). The structure scheme and grid are shown in Fig 3. The initial & boundary

conditions are set according to the experimental conditions.

(a)Three-dimensional model of flue-pipe reactor

(b) Tetrahedral meshes of inlet section of flue-pipe reactor

Figure 3. Structure scheme and grid

Distributions of temperature and NO

Fig 4 shows the distributions of temperature and contents of dominant reactants in the flue

pipe reactor. The initial temperatures of flue gas and reagent are 923K and 300K respectively, the

velocity of flue gas and reagent are 9.48 m·s-1

and 11.47 m·s-1

respectively, and the NSR value is 4.0.

From Fig 4(a), it’s found that the spraying of reagent only slightly affects the temperature

distribution near the reagent inlet region; the temperature distribution of the reactor appears

relatively stable. Fig 4(b) ~ (d) give the concentrations of NO, N2H4 and NH2 radicals respectively.

It’s found that the reagent N2H4 decomposes rapidly after spraying into the reactor, a large number of

NH2 radicals are generated in the middle region of reactor and then take part in the denitration

reaction. So the concentration of NH2 radical reaches a peak value in the middle and gradually

reduced at the second half of the reactor. The concentration of NO decreases rapidly from 450ppmv

at the inlet to 100ppmv at the outlet. Thus the time of the effective denitration reaction can be

confirmed, which is in the time range of 0.2s - 0.4s at 923K. Near the outlet region, the NO

concentration increases slightly because that the NH2 radicals for denitration have been used up and

meanwhile other nitrogenous compounds such as N2O, HNO etc. generates NO through reaction (8)

and (9) in the oxidizing atmosphere. That is to say, it takes 0.4s to accomplish the denitration

reaction at the temperature 923K, if the residence time is too long, the additional NO will be

generated through reaction (8) and (9).

(a) Distribution of temperature/K (b) Distribution of NO molar fraction

(c) Distribution of N2H4 molar fraction (d) Distribution of NH2 molar fraction

Figure 4. Distributions of temperature and molar fractions of gas species

OHNOOHHNO 2 (8)

NOOON 22 (9)

De-NO efficiency

Initial condition: NOini=360ppmv (900K), NSR=4.0,

O2 content: 9.8 %( higher temperature) ~15.8 %( lower temperature),

Figure 5. Comparison of de-NO efficiency between simulations and experiments

Fig 5 gives the de-NO efficiency predicted by CHEMKIN(PSR model), CHEMKIN/FLUENT

(CFD model) and measured by experiments respectively. Obviously, the results predicted by CFD

model are much better than that by PSR model, that is to say, the influence of flow on the de-NO

efficiency can’t be neglected during the SNCR process. The lower temperature window of CFD

model is 848-973K, and the maximum de-NO efficiency is 47.8%. The lower temperature window of

experiments is 837-961K and the maximum de-NO efficiency is 46.5%. So the de-NO efficiency and

temperature window predicted by CFD model are consistent with that measured by the experiments,

which means that the revised kinetics mechanism is applicable.

Influence of NSR value on de-NO efficiency

In the SNCR process, the NSR value affects the de-NO efficiency. In order to confirm the

optimum NSR value, the SNCR processes at different NSR values are simulated, and the results are

shown in Fig 6. When NSR value increases from 1.5 to 3.0, the peak value of de-NO efficiency

increases from 19.8% to 40.5%, the temperature window expands remarkably on both sides, and the

optimum temperature decreases from 906K to 850K; when NSR increases from 3.0 to 4.0, the peak

value of de-NO efficiency increases from 40.5% to 45.8%, the temperature window shifts to higher

temperature side, and the optimum temperature increases from 850K to 898K. Therefore, the

recommended NSR value is 3.0. When the NSR value is 1.5, the de-NO efficiency predicted by

simulation are slightly smaller than that measured by experiments. The reason is that the gas phase

heat-transfer model was applied in the process of CFD simulation, the latent heat of vaporization of

solution reagents was neglected by some assumptions in the process of simulations, which leads to the

initial temperature of flue gas in experiments is higher than that of CFD simulations.

Initial condition: NSR=1.5-4.0, O2 content: 13.5% (higher temperature) ~ 16.9% (lower temperature)

Figure 6. Influence of NSR on de-NO efficiency

Sensitivity analysis

Partial sensitivity analysis is applied to study the kinetic characteristic of the detailed

mechanism and confirm the key reactions and radicals in chemical reaction processes. In the

homogeneous reaction calculations, sensitivity coefficients are defined as

i

i

i

i

i

i

k

kF

k

kF

kF

k

ln

lnSi

(10)

Where Si is the partial sensitivity coefficient of the ith

reaction to the target function, F is the target

function (NO content in this research), and ki is the rate coefficient of the ith

reaction. Absolute value

of Si represents the influence degree. The bigger the absolute value is, the greater the effect on the

target function is. If Si is negative, the reaction will promote the reduction of NO; on the contrary, if Si

is positive, the reaction will prevent the NO removal.

In order to discuss the influence of NSR on de-NO efficiency, 5 dominant reactions at

different temperatures are selected from the denitration mechanism of hydrazine hydrate, the

sensitivity coefficients of dominant reactions at different temperatures are listed in Table 3.

Table 3. Sensitivity coefficients of NO at different NSR values

Temperature/K 833 857 893 956 1018

NSR 1.5 3.0 4.0 1.5 3.0 4.0 1.5 3.0 4.0 1.5 3.0 4.0 1.5 3.0 4.0

5.H+O2+M<=>HO2+M -1.283 -1.935 -2.267 -1.892 -3.265 -4.464 -3.424 -3.083 -2.283 -1.517 -1.436 -1.290 -0.678 -0.636 -0.710

33.NH3+OH<=>NH2+H2O -0.043 -0.320 -0.399 0.009 0.046 0.202 -0.017 -0.885 -1.510 -1.467 -1.837 -1.983 -1.687 -2.208 -2.311

34.NH2+NO<=>N2+H2O 0.105 0.157 0.020 -0.207 -0.902 -1.936 -1.942 -5.192 -5.830 -4.412 -5.134 -5.392 -4.236 -5.462 -5.710

87.N2H4(+M)<=>2NH2(+M) -0.555 -1.167 -1.697 -1.142 -2.984 -4.713 -2.871 -3.763 -2.960 -0.226 -0.378 -0.287 0.026 0.319 -0.549

58.NH2+O2<=>HNO+OH 0.060 0.291 0.240 0.220 0.775 1.636 1.596 5.203 6.277 5.007 5.839 6.305 4.976 6.888 7.358

From table 3, it’s found that the sensitivity coefficients of 5 reactions decrease when NSR

value increases from 1.5 to 3.0, except for reaction 58, which means that the de-NO efficiency

increases significantly. As NSR value increases from 3.0 to 4.0, the sensitivity coefficients of reaction

5, 34 and 87 decreases significantly. Therefore, when NSR increases from 3.0 to 4.0, increase of NSR

value has very little effect on de-NO efficiency. This also means that the recommended value of NSR

value should be 3.0.

Conclusion

The study of SNCR process by hydrazine hydrate allows us to make the following

conclusions.

1) The N2H4-NO-O2 kinetics mechanism is revised and verified by comparing the results of

numerical simulations and pilot-scale experiments.

2) The experimental results show that the effective temperatures of N2H4-based SNCR

process are bimodal distributed, the lower temperature window is from 820K to 960K, and the higher

temperature window is from 1260K to 1330K. The temperature windows changes little with different

NO concentrations.

3) The simulation results shows that the lower temperature window is from 848K to 973K,

the optimum temperature of NO reduction is 898K, and the maximum de-NO efficiency is 47.8%,

which is in accordance with the experiment results.

4) The recommended value of NSR is 3.0.

References

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plants [A]. POWER-GEN Europe [C]. Milan, Italy, 2008, 1-21.

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[J]. Prog. Energy Combust. 1989. Vol. 15. pp. 287-338.

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Combustion Institute, 1990, p. 297.

4. S. Azuhata, H. Akimoto, and Y. Hishinuma, The Behavior of Nitrogen Oxides in the

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Solution [J]. International Journal of Chemical Kinetics, 1999, 31(11):757-765.

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[J]. Comb& Flame, 2001, 124(1-2): 106-126.

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Phys. Chem., 1994, 98: 4034-4042.

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Appendix

Reaction mechanism of hydrazine-based SNCR process (750K≤T≤1150K)

[Rate Coefficients in Form k=ATnexp(-E/RT)]

Reaction A(cm3/moles·sec) n E(cal/mole)

R1. H2+O2 = 2OH 1.7E13 0.00 47780

R2. OH+H2 = H2O+H 1.17E09 1.30 3626

R3. O+OH = O2+H 4.0E14 -0.50 0

R4. O+H2 = OH+H 5.06E04 2.67 6290

R5. H+O2+M = HO2+M 3.61E17 -0.72 0

H2O/18.6/ H2/2.9/ N2/1.3/

R6. OH+HO2 = H2O+O2 7.5E12 0.00 0

R7. H+HO2 = 2OH 1.4E14 0.00 1073

R8. O+HO2 = O2+OH 1.4E13 0.00 1073

R9. 2OH = O+H2O 6.0E08 1.30 0

R10. 2H+H2O = H2+H2O 6.0E19 -1.25 0

R11. H+OH+M = H2O+M 1.6E22 -2.00 0

H2O/5.0/

R12. H+O+M = OH+M 6.2E16 -0.60 0

H2O/5.0/

R13. 2O+M = O2+M 1.89E13 0.00 -1788

R14. H+HO2 = H2+O2 1.25E13 0.00 0

R15. 2HO2 = H2O2+O2 2.0E12 0.00 0

R16. H2O2+M = 2OH+M 1.3E17 0.00 45500

R17. H2O2+H = HO2+H2 1.6E12 0.00 3800

R18. H2O2+OH = H2O+HO2 1.0E13 0.00 1800

R19. NH+O2 = HNO+O 1.0E13 0.00 12000

R20. NH+O2 = NO+OH 7.6E10 0.00 1530

R21. NH+NO = N2O+H 2.4E15 -0.80 0

R22. N2O+H = N2+OH 7.6E13 0.00 15200

R23. N2O+M = N2+O+M 1.62E14 0.00 51600

R24. N2O+O = N2+O2 1.0E14 0.00 28200

R25. N2O+O = 2NO 1.0E14 0.00 28200

R26. N2O+OH = N2+HO2 2.0E12 0.00 10000

R27. NH+OH = HNO+H 2.0E13 0.00 0

R28. NH+OH = N+H2O 5.0E12 0.50 2000

R29. NH+O = NO+H 2.00E13 0.00 0

R30. NH2+O = HNO+H 6.63E14 -0.50 0

R31. NH2+O = NH+OH 6.75E12 0.00 0

R32. NH2+OH = NH+H2O 5.0E11 0.50 1986

R33. NH2+NO = NNH+OH 8.9E12 -0.35 0

R34. NH2+NO = N2+H2O 2.77E20 -2.65 1258

R35. NH3+OH = NH2+H2O 2.04E06 2.04 566

R36. NH3+O = NH2+OH 2.1E13 0.00 9000

R37. NNH+NO = N2+HNO 5.0E13 0.00 0

R38. NNH+H = N2+H2 1.0E14 0.00 0

R39. NNH+OH = N2+H2O 5.0E13 0.00 0

R40. NNH+NH = N2+NH2 5.0E13 0.00 0

R41. NNH+O = N2O+H 1.0E14 0.00 0

R42. HNO+M = H+NO+M 1.5E16 0.00 48680

H2O/10.0/ O2/2.0/ N2/2.0/ H2/2.0/

R43. HNO+OH = NO+H2O 3.6E13 0.00 0

R44. HNO+H = H2+NO 5.0E12 0.00 0

R45. HNO+NH2 = NH3+NO 2.0E13 0.00 1000

R46. 2HNO = N2O+H2O 3.95E12 0.00 5000

R47. HNO+NO = N2O+OH 2.0E12 0.00 26000

R48. N+NO = N2+O 3.27E12 0.30 0

R49. N+O2 = NO+O 6.4E09 1.00 6280

R50. N+OH = NO+H 3.8E13 0.00 0

R51. HO2+NO = NO2+OH 2.11E12 0.00 -479

R52. NO2+H = NO+OH 3.5E14 0.00 1500

R53. 2NH = N2+2H 2.54E13 0.00 0

R54. N2H2+O = NH2+NO 1.0E13 0.00 0

R55. N2H2+O = NNH+OH 2.0E13 0.00 1000

R56. N2H2+OH = NNH+H2O 1.0E13 0.00 1000

R57. N2H2+NO = N2O+NH2 3.0E12 0.00 0

R58. NH2+O2 = HNO+OH 2.0E12 0.00 14893

R59. N2+M = N+N+M 1.0E28 -3.33 225051

N2/5.0/

R60. NH+M = N+H+M 2.65E14 0.0 75516

R61. NH+NH = NH2+N 5.95E02 2.89 2000

R62. NH+NH = NNH+H 5.1E13 0.00 0

R63. NH+NH = N2+H2 1.0E08 1.00 0

R64. NH2+M = NH+H+M 3.16E23 -2.00 91420

R65. NH2+NH = NH3+N 1.0E13 0.00 2000

R66. NH3+NH = NH2+NH2 3.16E14 -0.50 26776

R67. NH3+M = NH2+H+M 2.2E16 0.00 93491

R68. NH3+M = NH+H2+M 6.3E14 0.00 93410

R69. NH3+NH2 = N2H3+H2 1.0E11 0.50 21604

R70. NNH+M = N2+H+M 1.0E13 0.50 3060

R71. NNH+N = NH+N2 3.0E13 0.00 2000

R72. NNH+NNH = N2H2+N2 1.0E13 0.00 4002

R73. N2H2+M = NH+NH+M 3.16E16 0.00 99423

N2/2.0/ H2/2.0/

R74. N2H2+N = NNH+NH 1.0E06 2.00 0

R75. N2H2+N2H3 = N2H4+NNH 1.0E13 0.00 6001

R76. N2H3+M = NH2+NH+M 5.0E16 0.00 60014

R77. N2H3+M = N2H2+H+M 1.0E17 0.00 33006

R78. N2H3+H = N2H2+H2 1.0E13 0.00 0

R79. N2H3+H = NH2+NH2 5.0E13 0.00 2000

R80. N2H3+H = NH+NH3 1.0E11 0.00 0

R81. N2H3+N = N2H2+NH 1.0E06 2.00 0

R82. N2H3+NH = N2H2+NH2 2.0E13 0.00 0

R83. N2H3+NH2 = N2H2+NH3 1.0E11 0.50 0

R84. N2H3+NNH = N2H2+N2H2 1.0E13 0.00 4002

R85. N2H3+N2H3 = NH3+NH3+N2 3.0E12 0.00 0

R86. N2H3+N2H3 = N2H4+N2H2 1.2E13 0.00 0

R87. N2H4(+M) = NH2+NH2(+M) 5.0E14 0.00 60000

LOW/1.5E15 0.00 39000/

N2/2.4/ NH3/3.0/ N2H4/4.0/

R88. N2H4+M = N2H3+H+M 1.0E15 0.00 63614

N2/2.4/ NH3/3.0/ N2H4/4.0/

R89. N2H4+H = N2H3+H2 7.0E12 0.00 2501

R90. N2H4+H = NH2+NH3 2.4E09 0.00 3101

R91. N2H4+N = N2H3+NH 1.0E10 1.00 2000

R92. N2H4+NH = NH2+N2H3 1.0E09 1.50 2000

R93. N2H4+NH2 = N2H3+NH3 1.8E06 1.71 1381

R94. 2H+M = H2+M 6.5E17 -1.00 0

H2/0.0/

R95. 2H+H2 = 2H2 1.0E17 -0.60 0

R96. NH+H = N+H2 3.2E13 0.00 325

R97. NH+N = N2+H 9.0E11 0.50 0

R98. NH+H2 = NH2+H 1.0E14 0.00 20075

R99. NH2+N = N2+H+H 6.9E13 0.00 0

R100. NH2+NH = N2H2+H 1.5E15 -0.50 0

R101. NH2+NH2 = N2H2+H2 1.0E13 0.00 1500

R102. NH3+H = NH2+H2 5.43E05 2.40 9922

R103. NNH = N2+H 3.0E08 0.00 0

R104. NNH+NH2 = N2+NH3 1.0E13 0.00 0

R105. N2H2+M = NNH+H+M 5.0E16 0.00 50011

N2/2.0/ H2/2.0/

R106. N2H2+H = NNH+H2 8.5E04 2.63 230

R107. N2H2+NH = NNH+NH2 1.0E13 0.00 6001

R108. N2H2+NH2 = NH3+NNH 8.8E-02 4.05 1610

R109. CO+O+M = CO2+M 6.2E14 0.00 3000

H2/18.6/

R110. CO+OH = CO2+H 1.5E07 1.30 -765

R111. CO+O2 = CO2+O 2.5E12 0.00 47700

R112. CO+HO2 = CO2+OH 1.5E14 0.00 23650

R113. NO2+CO = CO2+NO 9.0E13 0.00 33800

R114. NO+OH+M = HONO+M 5.1E23 -2.51 -68