B.A.R.C-530

Uai<03

GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION

WATER CHEMJSTRY STUDIES - I!fUSE OF HYDRAZrNE FOR SCAVENGING DISSOLVED

OXYGEN IN HIGH TEMPERATURE WATER - A REVIEW

H S. Mahal and K. S. VenkateswarluChemistry Division

BHABHA ATOMIC RESEARCH CENTRE

X , BOMBAY, INDIA_

11971 .i

B.A.R. C. ^530

S GOVERNMENT OF INDIA'. ATOMIC ENERGY COMMISSION

O

WATER CHEMISTRY STUDIES - i nUSE OF HYDRAZINE FOR SCAVENGING DISSOLVED

OXYGEN IN HIGH TEMPERATURE WATER - A REVIEW

H. S. Mahal and K. S. VenkateawarluChemistry Division

BHABHA ATOMIC RESEARCH CENTREBOMBAY, INDIA

1971

WATER CHEMISTRY STUDIES - III :TJSE OF HYDRAZINE FOR SCAVENGING DISSOLVED

OXYGEN IN HIGH TEMPERATURE WATER - A REVIEW

H. S. Mahal and K. S. Venkateswarlu

In water-cooled reactors, in order to minimise corrosion,

it is essential to keep the dissolved oxygen content in coolant water

at a very low level. Different procedures exist by which water is

deoxygenated. One of the more promising methods involve the uee of

hydrazine (N^H^). In view of the importance of this procedure for the

operation of high temperature water loops, Reactor Engineering Divi-

sion, Bhabha Atomic Research Centre, is contemplating to use it. As

such it is considered desirable that the available information on this

topic be put together in the form of a report for ready reference.

ADVANTAGES OF THE USE OF HYDRAZINE

(1) One of the advantages of using hydrazine is that tts de-

composition and oxidation products do not increase the dissolved

solid content of the water. Hydrazine reacts with oxygen to give

nitrogen and water.

(2) 1% of hydrazine solution gives a pH = 9. 9. As the re-

action is alkaline, this is an advantage because stainless steel and

carbon steel do not corrode in alkaline medium. Moreover, in the

long run we may have to add less of alkali to maintain the pH at about

IP, and this amounts to saving in operational costs.

- 2 -

(3) With hydrazine treatment, the pH rises a little due to the

formation of ammonia and due to this rise in pH, the pick-up of Fe and

Cu in water drops to low levels, indicating lesser corrosion. Straub

8c Ongman have shown that for a pH = 8-9 no iron or copper goes into

solution.

(4) Since it is a powerful reducing agent, it reacts with other

oxidising agents. Chlorine and hypo-chlorous acid rapidly and quanti-

tatively oxidise hydrazine to N2- Theoretically, 1 ppm N,H^ reacts

with 2. 23 ppm of chlorine.

(5) The reaction is catalysed by metal surfaces. This is

important Bince the r saction proceeding more rapidly at the surface of

the metal pipe than in the bulk ox the liquid, provides protection to the

metal against pitting by the oxygen.

In view of the above advantages, hydrazine has been suggested

for nearly complete scavenging of dissolved oxygen in nuclear reactor

feed water. For example, the dissolved oxygen content of high tem-

perature water in Reactor Engineering Division's primary pump

testing loop should not exceed 20 ppb and hydrazine is to be employed

to achieve this. It is to be noted that when the coolant under consi-

deration is D2Qf it would be preferable to deoxygenate it by deutra-

zine, N2D4 rather than N2H4 as the use of- N2H4 will lead to isotopic

dilution of D->O.

-3-

REACTIONS OF KYDRAZINE IN BOILER WATER

Hydrazine hydrate and its salts have found their greatest

use in boiler feed-waters as oxygen scavengers. Leicester* *> and

(2)A d a f t l B h a v e reported that the reaction between hydrazino r^

oxygen in cold distilled water or at room temperatures may be non-

existent, or very very slow. Leicester states that there is some

evidence to show that if water and hydrazine are in very pure state,

hydrazine and the dissolved oxygen reaction may not occur at all.

Experiments in glass vessels phow that heat, pH or catalyst is

required to initiate the reaction between hydrazine and dissolved

oxygen in water.

Hydrazine is a reducing agent and reacts with dissolved

oxygen to give nitrogen and water.i

N2H4 + O2 » N2 + 2H2O . . . . . . (1)

The main factors in determining the rate of the process

are excess of hydrazine, initial concentration of dissolved O2, the

temperature and pH of the medium. In practice, the reaction is not

so simple but nevertheless the equation describes the net result of

oxygen removal. As at high temperatures hydrasine gives ammonia,

it is desirable that the reaction between hydrazine and oxygen should

be completed before the feed water enters the boilers

3N2H4 — — > 4NH3 + N2 (2)

However, under the conditions existing in boilers, reaction

(1) should predominate. If the concentration of N2H4 is considerably

-4 -

in excess, then the decomposition ye action (2) occurs.

Another reaction of N H. which is of interest, particularly

when starting hydrazine treatment, if thfct with metal oxides, e.g.«

N2H4 + 6Fe2O3 »N2 + 2H2O + 4Fe3O4 (3)

During the reaction of hydrazine with ferric oxide, which ie present

in water and on the metal surface, more of hydrazine is consumed in

the first period of hydrazine treatment, requiring an initial dosage

that is greater than that necessary after the boiler is conditioned.

Stones^) gives three mechanisms which will explain the

reaction between hydrazine and oxygen:

1) Homogeneous Reaction, occurring in the solution as a

simple bimolecular reaction represented by the following equation:

N2H4 + O2 > N2 + 2H2O (4)

2) Surface adsorption reaction, a heterogenous reaction

after adsorption on the Butrface of metal ions

* N2 + 2H2O . . . . (5)jadsorbed

3) Heterogenous Reaction, in which the ferric oxide in the

boiler and feed lines is reduced by N2H4 to ferroso-ferric oxide

which is then converted to the ferric state by dissolved oxygen

{the process is cyclic and continuous),

4Fe3O4

-5 -

The experimental work of Gilbert^, Wickert*5) and Audrieth^ shows

that at and near the saturation concentration of O-, the reaction bet-

ween N2H^ and O2 ia not instantaneous.

It has been shown that during N2H4 treatment of water, NH-

appears in the superheated steam of high pressure boilers and in the

condensates of drains and turbines. The appearance of NH3 is the

result of the thermal decomposition of excess N-H^ in qteam according

to equation1 (2).

The decomposition of N2H4 between 140°-240°C has been in-

vestigated and it is found that the results can be extrapolated to higher

temperatures with a fair degree of accuracy' ' '. The reaction obeys

the equation

log c . krC o 2.303

where k = velocity constant of the reaction, C = concentration of

videcomposed N2H4 and CQ = its initial concentration, and ***= time

of decomposition. IfC,Co , % are measured, then k can be cal-

culated for various temperatures. It is seen from the-above that the

time required for the decomposition of half of the N2H4 does not

depend oa the initial concentration of the compound

f , . 0.6932 k

This conclusion is of practical significance since after obtaining

reliable data concerning the half-time of large amounts of N2H4, it

is possible to calculate its residual concentration after passing

through steam super-heater. This problem has not yet been solved by

chemical analysis. Processing of the date according to the above

method gives 7 1 at various temperatures of interest as given below;

TABLE I

Time required for the decompositionTemperature in °C of half of the hydrazine (*ZTl )

16O°C ^ 307.7 Sees

200°C. 41 sees

250°C 6.5 seca

300°C 1.5 sees

The plot of log Ifck of N-H4 against the absolute textiperature

indicates that It U • ivereely proportional to the latter. The data can

be 'extrapolated to higher temperatures also. It will be seen that

under the actual existing operating conditions of this equipment (high

pressure steam generators with steam superheating), negligibly small

traces of N_H. are present in the superheated steam.

Theoretically, in order to scavenge 1 PPm of O^ from

boiler water, 1 ppm of hydrazine is required provided the efficiency

and purity are 100%, but this is not usually the case, so excess

N,H. is required in practice.

-7-

AMMONIA FORMATION

It has already been mentioned that traces of N7H4 and NH3

in the condensate are an advantage since they help to maintain the

pH = 8-9. Above 350°C, decomposition of hydrazine further raises

the pH. Thug, if the concentration of N2H4 is considerably in excsea

of that required to react with dissolved oxygen, then a part of it de-

composes to give ammonia.

The low copper and iron pick-up is probably due to the

increase of pH of the condensate and suggests that if O? and CO2 are

low, ammonia is effective in reducing the amount of metal pick-up' "'.

Leicester^1' has shown that in an Italian plant'the ratio of

° 2 : ^2^4 a t t n e t^m e o f starting it was 1: 1.5, later on it was reduced

to 1 : 1.2 and even under these conditions, the reducing cycle was

maintained, while the pK rose from 8. 8 - 9.1 in the condensate due

to the presence of 0.1 ppm of NH3. '

HYDROGEN FORMATION

In some tests with the experimental boiler. Jaeklhr '

observed that hydrogen is also one of the decomposition products of

N2H4 at 1500 p. s. i. The addition of 0.5 ppm of N ^ to the feed-

water caused an increase of 6 ppb of dissolved hydrogen in the steam,

corresponding to about 10% of hydrogen added as hydrazine. There

is also data concerning the decomposition of N2H4 at temperature

269* - 637°C with evolution of hydrogen'3'

- 8 -

2 4 2 N H 3 + 2N2 + 3H2 (8)

In an operating reactor, due to radlolysis of water, molecular hydro-

gen is formed in the coolant. It is assumed that the additional H2 from

N2H4 is very much less than the radiolytic yield.

THE VARIABLES IN N2H4 REACTION WITH OXYGEN - TEMPERATURE,PRESSURE, pH, CATALYSTS

The reaction between hydrazine and oxygen at room tempera-

tures is very very slow, but at higher temperatures the rate increases.

Upto 70°C the reaction rate increases to slighly more than double

every 10°C.

Ellis and Mor eland* ' performed the experiments on the

reaction between N2Hj and oxygen at 20 C using pure water. A 10%

excess N-H^ was used. The experiments were performed in all glass

apparatus. The rates of reaction were also determined at 35°C and

51°C. Over this temperature range, there is a Bmall increase in the

rate with temperature. Though the rate is approximately doubled tor

every 10°C rise in temperature, It ia still low. Even at 51°C, only

60% of the O2 reacts after 10 hours. Assuming the reaction rate to

be doubled for every 10°C rise, at 170°C the time would be only a

few seconds.

Influence of pH

The pH of the water also affects the rate of reaction between

N2H4 and oxygen. The rate is higher between pH 9 and 11 than below

-9 -

9 and falls abruptly beyond pH 11. At pH 10. 5, the rate of reaction is

maximum. Also, the rate of reaction at pH 9 is nearly half of thak at

pH 10.5. A marked increase in the rate is seen -when the pH la

increased from 7 to 9. With increase in pH to 11, the rate falls off to

an intermediate value. This is in agreement with the findings of Gordon,

who found N2H. to be a most effective reducing agent in the pH range

9-10. B. This fact is important since the boiler feed waters are con-

trolled in this pH range. The primary coolant in RAPP is also main-

tained at pH 10. However, the rates are still low and further modifi-

cations are necessary to increase them. The purity of water also

affects the rate of reaction. The reaction is much slower as the

purity of water increases.

Catalysts

Copper salts and activated carbon are the best catalysts in

increasing the rate of reaction between N_H4 and oxygen. The reaction

is catalysed at the surface. This is important since the reaction pro-

ceeding more rapidly at the surface of the metal than in the bulk of t h e ^

solution protects the metal from pitting by oxygen attack. . The effect

of N2Hg is to reduce the O2 concentration at the metal surface.

Ferric oxide also acts as a catalyst in the N2H4/O2 reaction.

Ferric oxide is first reduced by the N2H4 to ferrosoferric oxide (black)

and O2 is removed by oxidising the magnetite back to hematite. This

is ; supported by the fact that some two weeks are required even when

using 100% excess N2H4 before the latter can be detected in the boiler

-10-

water. It appears that this time is required for the N_H - to reduce

all the ferric oxide in the system to Fe^O. and only after this reaction

is completed, it is possible for the excess to build up a residual and

also produce NH3. Discontinuation of N2H^ addition even for long

periods still results in the complete deoxygenation of the steam. The

probable explanation is that the reduced iron oxides continue to remove

O, to such times till they are reoxidised.

The catalytic effect of metal ions Cu++, Fe+ + , Co**, Nl++#

Cr+++, and Mn++ (added as sulphates) in concentrations giving 1 ppm

of the metallic ions has been studied. Usually hasiness develops in

the reaction flasks after the addition of hydrazine, presumably due to

the formation of an insoluble reduced complex. The presence of 1

ppm of either Cu++ or Co"*"*" ions gives a great increase in the rate of

reaction; the reaction is completed in 4 hours at 20°C.

Heterogenoua Catalysts

Here a solid insoluble meterial is immersed in solutions BO

as to present a relatively large area to the reactants. With Cu

gauze, the reaction with O2 is complete in 5 hours at 20°C. The

effect of glass wool is interesting because it gives a considerable

increase in the fate of reaction. It suggests that the reaction is

catalysed at the surface and that the increase in the rate is due to

the large surface area.

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Copper Column

In water containing 40% N2H4 and Na3PO4, to bring the pH

to 9-10 when passed through a glass column of 1 inch diameter packed

with bright Cu turnings to a height of 55 cm., the reaction occurs

rapidly but less BO compared to activated carbon. The time of con-

tact is varied by varying the flow-rate. The quantitative results are

summarised in Table II.

TABLE II

Results of Experiments Using Copper Column

Rate of flow Estimated O contentTemp. °C cm/Bee time of 2 of H_O % O,

contact, sec. emerging removedmg/1

20 0.12 324 0.4 95

23 0.25 156 4.6 40

38 0.33 120 1.5 75

As mentioned before, activated carbon is also used to remove

oxygen dissolved in water in presence of ^ H ^ . It has beeh shown

that the grade of activated carbon has little influence on the reaction

between oxygen and N2H4 . Some typical results given in Table IH show

that the reaction is complete in 90 sec. at 20°C and in 9 sec. at 42°C.

Addition of a trace of CoSO4 does not increase the reaction. In Germany

and Italy, activated carbon is used for O2/N2H4 reaction in the de-

oxygenation of boiler feed-waters.

Length ofcolumn, cm

100

100

29

29

29

29

• 2 9

10

Results

. Temp.°C.

20

20

16

20

20

42

20

42

18

-12-TABLE HI

of Experiments using

Rate offlowcm/sec

0.090.55

1.67

1.480>8

1.67

1.38

1.51

1.67

EBtimatedtime ofcontact,sec.

600

90

9

10

32

11

3 . 3

9

Carbon Column

1 O, contentofH2Oemerging

mg/1

0 . 1

0 . 1

4 . 8

2 . 4

0 . 9

0.15

1 . 0

2 . 0

3 . 0

% o2removed

>98

> 9 8

40

70

90

>97

87

65

60

* using 200% excess N2H4

@ Water had 2 ppm Cu++

Note: 0.1 mg O /I is the lower limit of the method of analysis used.

Ellis' t has likewise reported that, When the feed temperature

is < 100°C and oxygen concentration is high, deoxygenation can be*

achieved using the theoretical amount of N~HJ and passing the water

through a carbon bed as catalyst to accelerate the reaction. The use

of a filter containing a special active carbon for catalysing reaction,

is also recommended. The carbon assumes the function of an autof e-

gulaior, absorbing the excess N-H^ and restoring it when there i s

deficiency. Furthermore, the filter extracts any Cu in suspension

in the water and therefore a carbon filter, is recommended where the

Cu content is high.

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How much Excess N2H4 can be Employed - The Place of Addition

In his paper on 'boiler feed water treatment and oxygen

scavenger' Ellis* ' mentions that in a high pressure boiler, because

of the high temperature of the boiler feed water, hydrazine reacts

rapidly with oxygen. After thermal deaeration, 50 to 300% excess hy«-

drazine above the theoretical amount is added to the feed and thus a

small excess is maintained in the boiler.

Zanchi describes the results obtained at Taveiszan'o,Power

Station using cylindrical shell boilers generating steam at approxima-

tely 1800 p. B, i. and 520°C. Copper was present In the circuit. The

feed water after deaeration contained 0. 01 ppm O2 and approximately

400% excess hydrazine was added at 130°C. The exact amount of NgH.

added was varied to give a pH 8. 5 in the feed water. A residual of

5 ppm of Na2SO3 was maintained in the boiler.

Using photometric O-toluidine method, no O2 was detected in

the saturated and superheated steam; also there was no hydrazine in

the steam and NH3 content was 0.1 - 0.2 ppm. The boiler had 0. 02

ppm copper and in the steam less than 0. 002 ppm copper. The Fe

content was 0. 02 - 0. 03 ppm in the circuit.

Practical experience in the use of hydrazine for boiler feed

water treatment has shown that the amount of hydra*lne added should

not exceed three times the amount of oxygen content of the deaerated

feed water. Initially hydrazine is consumed by any Fe2O3 present.

So the initial hydr&zime dosage must be higher than that when the

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boiler 1B conditioned. It is necessary to maintain"a certain residual

value in the boiler once it is conditioned, The maximum residual..

varies from boiler to boiler ranging from 0. 05 to 0. 25 ppm with a

typical value of 0.1 ppm. The corresponding hydrasine addition

ranges from 0. 005 to 0. 03 ppm hydrazine in tha boiler feed water.(3)

According to Stones , initially hydrazine reacts with

and CuO as follows:

, , , N , ,+ 2H,O + 4Fe,O, -v •2 - * Z 4 £ 2 3 4 I-..(9)

4CuO + N 2H 4 ^ N 2 + 2H2O + 2Cu2O j

No further reduction of FeJO^ takes place. These reactions account

for the fact that on starting-up a high pressure boiler even when using

100% excess hydrazine, some two weeks pass before a residual of the

deoxidant is found in the boiler.

The addition of N-Hg 100% in excess of the oxygen value to

a boiler (at Duston) of 625 psi resulted in a fairly rapid rise of NH3 ,

concentration and thus in an increase in the pH of the condensate,

while a 50% excess of hydrazine just maintained a hydrazine residu'al

in the boiler and resulted in a lower NH-j concentration in the steam*

without affecting the pH and metal pick-up. When 700% excess of

hydrazine was used, there was an increase in (1) N^Hi boiler residual,

(2) increased NH- concentration, and (3) presence of small amounts

of hydrazine in the saturated steam. .,

Kot" *) has mentioned that from the experience gained during

the operation of electrical power plants where N,H. treatment of water

-15-

was employed, it w t i found that only the decomposition of hydrasine

with the evolution of NH3 was of any practical importance.

To sum up, good results in the removal of oxygen are

achieved when N2H4 is introduced in amounts 2-3 times that of the

residual oxygen remaining in the water after deaeratien. The excess

of hydrazine should be maintained at a level 0. 02 - 0. 03 mg/litre.

In order to protect N2H4 from oxidation by air the container

1B sealed with Teflon lining which is removed when the container is to

be filled or emptied. Filling of the container with N2H4.H2O or its

emptying is carried out by gravity flow or N, pressure. Prior to

N9H4 treatment of the water the internal surfaces of the feed circuit

and steam generators is cleaned for any deposits of Fe and Cu oxides.

AH connecting parts, fittings and containers of the dosage device for

the introduction of N2H4 (Fig. 1) must be checked for leaks. Before

the introduction of N2H4, a number of feed water samples is taken for

the determination of O2, Fe and Cu oxides aad sometimes NH3. From

the results obtained, the first portions of N2H4 to be added is calculated.

Hydrazine treatment of water is carried out in two stages,

or continuously; First, an increased (provisional) amount of hydrasine

solution is added to achieve a "saturation of the system" followed by

the introduction of normal amount of the reagent serving for the nearly

complete removal of oxygen.

The increased (provisional) amount of N2H4 Is calculated f«**a

the oxygen content and the content of Fe(m) and Cu{ll) oxtdea in the

-16-

deaerated feed water before N2H^ treatment. For calculation, the

following formula is used:

g; = 3cj + 0. 3c2 + 0. 15c3 . . . (10)

gi = the increased provisional amount of N9H4 mg/1;

c. = concentration of O2 in the feed water before the introduction'of

N2H4; c, = concentration of Fe^O, mg/1, c , = concentration of

CuO mg /I.

REAGENTS CONTAINING N2H4 GROUPING

Hydrazine salt of dinaphthyl methane disulphonic acid was

used in some instances as (a) this material was alkaline'in nature

and did not affect the pH control of the boiler, (b) it is a very active

dispersing agent and thus assists in fluidiuing any solids in the boiler,

(c) in view of the catalytic effect of the ion exchange resins on the

N2H4 - O2 reaction, it was thought that sulphonated naphthyl radical

of this compound might assist the reaction, and (d) the dry meterial

had approximately 11-15% available l^H^. It is also highly soluble in

cold water. Initial tests by using sufficient amount of this compound

to give 200 - 300% excess of hydrazine, showed that the amount of

oxygen removed at the feed pump (at 150°F), increased from 60 to 80%

and in the boiler water from 86 to 91%. At 203°F, the oxygen re-

moved at the feed pump discharge showed an increase from 81 -

and in the boiler water from 94 - 96%. Table IV gives percentage

removal of O_.

TABLE IV

Summarized Results of Pilot-Plant Boiler Tests__.__«>——__••—.••—._.• ._.— — — . — . - _ _ — • - _ _ . — — ••—>•——.•- . — _ — . _ — _ — _ — _ » — _»—.—.—.—.—I — . — . — — . — . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ " • » • » • »

Percentage of_ . . Conditions of trial. Original O-> removedl rial • __,__.-._._.-,-,-._,_.-._._._,_.-_.._____-___.-_,_-_-_._.___.__.._-._- _----«.___« A. ___________Series Oxygen, scavenger 0~ in feed- Temp, of Sampled at Sampled at

No. used water ppm feed water Feedpump boiler guage°F discharge glass

I NZH4.H2O 0.02 150 31 55

II Dihydrazine Phosphate 0.0Z 150 32 55

m NZH4.H2O 0.20 150 60 84

IV DihydraKixte Phosphate 0.20 150 58 86

V N2H4 .%O 0.20 203 81 94

VI N,H_. R2O + activated-2 4 charcoal ° - 2 0 1 5 ° 7 2 ^0

VU N 2H 4 M l tofdinapthyl .methane disolphonilcacid

Yin -do- 0.20 203 86 r/6

-4t

-18-

PLANT EXPERIENCE ON Fe 2 O 3 AS CATALYST

Leicester' ' Las mentioned that oxide films, on the surface

of a solid or on suspended particles in solution, may provide the

necessary sites for N^H^ - C*2 reaction.

In a pilot-plant boiler at. the Admirality Materials Labora-

tory, experiments were conducted at 500 p. s. i. g, -and It was observed

that the N2H4 - O, reaction is dependent on surface properties. It

would appear that the initial reaction machanism might well be between,

hydrazine and Fe2O^( thereby reducing iron to the ferrous condition and

this is followed by the reoxidation of ferrous to ferric by dissolved

oxygen of the feed water. This would certainly seem to be the case in

the example quoted, as a change from red coloration of ferric oxide

to the black colour of the ferrous oxide was observed after the addition

of N^H.. When the hydrazine addition was stopped, removal of dis-

solved C*2 continued until the ferrous oxide in suspension in the boiler

water had become fully oxidised to the original ferric state. This is

a typical case where the presence of a suspension of iron oxide in the

feed water may provide a large oxide surface area to catalyze the

N,H . reaction with dissolved oxygen.

HAZARDS AND SAFETY PRECAUTIONS

1) Hydrazine should be stored in a cool place (<40°C)

to prevent possible fires or explosions from the vapours.

2) The feed solution should be added to a stainless steel

tank filled with water.

-19-

3) Rusty containers should not be used as hydrazine may react

violently with Fe2O3 .

4) Inhaling of sharp irritating vapours (>100 ppm) should

be avoided.

5) Rubber gloves, goggles, mask or other protective equip-

ment should be used to prevent solution or vapours from coining into

contact with skin.

6) Affected skin should be washed with soap immediately

after flushing with water. Some individuals get dermatitis even on

contact with small amounts of N2H4.

7) N2H . reacts exothermically and often violently with many

oxidising agents, and contact with these should be avoided.

8) The area of metal exposed to hot N^H^ vapour should be

kept to a micimum.

9) The equipment should be flushed well with water before

opening for repairs.

10) Freshly fabricated equipment should be treated well with

diluted N2H4 to deactivate catalytic surfaces.

-20-

REFERENCES

1. Leicester; Trans A. S. M. E. 7<3, 273(1956)

2. Adams; Trans. A.S. M.E. 78, 273 (1956).

3. Stones; Chem & Ind. 120-8 (1957)

4. Gilbert; J. Am. Chem. Soc. 51., 2744 (1929)

5. Wickert; Arch. MetaU-Kunde 3_, 113(1949)

6. Audrieth; Ind. Engg. Chem. 43, 1774 (1951)

7. Straub; Combustion J_, 34 (1957)

8. Woodward; Power No. 11, 80(1956)

9. Alexander and Rununel; Trans. A. S. M.E. 72» 519(1950)

10. Jacklin; Trans. A.S.M.E. 78, 273 (1956)

11. Kot; Water and water treatment in Nucl. power plant p. 98

12. Ellis & Moreland; Chem. Process Engg. p.47 (1956)

13. Ellis; Chem. Process Engg. p. 81 (1955)

Condensateinput

Discharge of solution-*-into water treatment

tank

Fig.1 Diagram of the Installation for the introduction of Hydrazine.t

1 Portable tank, capacity30Ut.2. Dosage tank with 1-5 ttr each.3. Glass liquid level indicators.

4 Plunger type dosage device.