THE INHIBITIVE ACTION OF MAGNESIUM HYDROXIDE ON HOT ASH CORROSION OF STAINLESS STEEL IN A KEROSENE FIRED FURNACE

Abstract

ABSTRACT:- The inhibitive effect of magnesium oxide on the hot ash corrosion of steel structures of power generation station was studied using a kerosene fired furnace. Three alloys were selected including [SA 178A, 209 T1, 213 T11], prepared as rectangular pieces from water wall tubes and superheater tubes of a local power station. The heating chamber of the furnace had shelves on which specimens are placed. Mg(OH)2 was mixed with synthetic slag (67%wt V2O5 and 33% wt Na2SO4) at molar ratios of 1:1, 1:2 and 1:3, respectively and applied on the surface of the cleaned specimens. The tests were carried out at fixed (4 h) and various time intervals (2-10 h) to study the normal oxidation at various temperatures (550-950˚C). The rate of oxidation is accelerated in the presence of vanadic slag and resulted in increased corrosion rate with increasing temperature (550-950 oC ). X-ray diffraction indicated the formation of NaV3O8, Na2O.V2O4.5V2O5, Na4V2O7, VOSO4, Na2SO4 and iron oxide (Fe2O3) . The weight loss of the three alloys specimens indicated a Clear reduction in the degree of corrosion with increasing Mg(OH)2 content. The scale changed into a powder form which can be easily removed from the surface of the specimens. The best results were obtained with the mole ratio 3:1, which gave inhibition efficiency of 85% at 550°C. The inhibition efficiency increases with temperature decrease. With the introduction of Mg(OH)2 with the ash magnesium vanadate Mg3V2O8 was a major constituent together with some MgO

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ISSN 1999-8716
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First Engineering Scientific Conference
College of Engineering –University of Diyala
22-23 December 2010, pp. 391-405
THE INHIBITIVE ACTION OF MAGNESIUM HYDROXIDE
ON HOT ASH CORROSION OF STAINLESS STEEL IN A
KEROSENE FIRED FURNACE
M. M. Barbooti1, S. Al-Niaimi2, and K. F. Al-Sultani3
(1)School of Applied Sciences,
(2)Department of Chemical Engineering, University of Technology
(3)Department of Chemical Engineering, University of Babel.
ABSTRACT:- The inhibitive effect of magnesium oxide on the hot ash corrosion of steel
structures of power generation station was studied using a kerosene fired furnace. Three
alloys were selected including [SA 178A, 209 T1, 213 T11], prepared as rectangular pieces
from water wall tubes and superheater tubes of a local power station. The heating chamber of
the furnace had shelves on which specimens are placed. Mg(OH)2 was mixed with synthetic
slag (67%wt V2O5 and 33% wt Na2SO4) at molar ratios of 1:1, 1:2 and 1:3, respectively and
applied on the surface of the cleaned specimens. The tests were carried out at fixed (4 h) and
various time intervals (2-10 h) to study the normal oxidation at various temperatures (550-
950˚C). The rate of oxidation is accelerated in the presence of vanadic slag and resulted in
increased corrosion rate with increasing temperature (550-950 oC ). X-ray diffraction
indicated the formation of NaV3O8, Na2O.V2O4.5V2O5, Na4V2O7, VOSO4, Na2SO4 and iron
oxide (Fe2O3) . The weight loss of the three alloys specimens indicated a Clear reduction in
the degree of corrosion with increasing Mg(OH)2 content. The scale changed into a powder
form which can be easily removed from the surface of the specimens. The best results were
obtained with the mole ratio 3:1, which gave inhibition efficiency of 85% at 550°C. The
inhibition efficiency increases with temperature decrease. With the introduction of Mg(OH)2
with the ash magnesium vanadate Mg3V2O8 was a major constituent together with some
MgO.
Keywords:- Magnesium Hydroxide, Hot Ash corrosion, Inhibition.
Diyala Journal
of Engineering
Sciences

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INTRODUCTION
Singh et al(1) recently reviewed the coupled action of sodium sulfate and vanadium
pentoxide on the corrosion of iron and nickel super alloys in power generation stations. They
concluded that It is basically induced by the impurities such as Na, V, S, etc. present in the
coal or in fuel oil used for combustion in the mentioned applications. Ash fouling and flame-
side corrosion of metal surface, together with heat transfer surface fouling are major
problems in power generation stations when burning heavy oils. Vanadium occurs in the form
of porphyrinic and non-porphyrinic in crude oils (2). These compounds decompose in the gas
stream to give mainly vanadium pentoxide (V2O5), which is most damaging due to its low
melting point (690°C) i.e. it is in its liquid state at normal combustion temperature. Sodium
in the oil is mainly present as (NaCl) and is readily vaporized during the combustion process
(3). The presence of a liquid phase on the surface of a metal is usually necessary for corrosion
reactions to occur at high rates. The most likely liquid phases are based on vanadium
pentoxide and sodium sulphate complexes depending upon the exact analysis of the fuel
used(4). A series of compounds are formed between (Na2O) and (V2O5), some of which have
melting points below the operating temperature of boilers and turbines. The eutectic formed
between (5Na2O.V2O4.11V2O5) and sodium metavanadate (Na2O.V2O5) melts at (527°C).
However, under an atmosphere containing oxides of sulphur, other components can
form e.g. Na2SO4, Na2S2O7 , V2O5. 2SO3 and V2O5.1/2 SO3 (5).
Prevention of hot ash corrosion is impossible and a reduction can be effectively
performed. In contaminated combustion atmospheres, there are three basic ways to reduce the
corrosion problems and these are:-
I-Removal of harmful impurities presents in the environment.
II-Addition of a compound to counteract the harmful impurities .
III-Changing the combustion condition to minimize attack.
The use of water-in-oil emulsions is a promising technique to reduce smoke, NOx
emissions and reduction in SO3 formation. This aids the elimination of metal-containing
antismoke additives and the resulting deposits and fouling in gas turbines, the ability to use
heavier and cheaper fuel(6).
The use of corrosion resistance coatings for existing alloys is widely used in the gas turbine
and boiler field. Metallic coating of silicon, chromium, aluminum, zirconium and beryllium

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was studied (7), as well as ceramic coatings. The higher the chromium content of the alloy, the
better would be the hot-corrosion resistance (7). El-Dahshan (8) observed that Co-Cr-W alloys
were more resistant to oxidation than (Ni-Cr-W) alloys when coated with sodium sulphate.
The corrosive effect of ash-causing contaminants, principally vanadium and nickel can
be neutralized by chemical additives. The additives work by forming a stable vanadate of
higher melting point than the vanadium compounds originally present, thus preventing
formation of a liquid phase at the operating temperature (9, 10). Macfarlane (4), reviewed the
effect of such additives in particular calcium, magnesium and zinc compounds. Magnesium
additions, however, raise the melting point of the deposit appreciably from 680C for
1/2MgO.V2O5 to 1100C for 3MgO.V2O5 and have been fond to be very effective.
3MgO + V2O5 Mg3V2O8 ……………...(1)
The Mg3V2O8 is solid at the operating temperature of industrial boiler tubes and turbine
blades(11, 12). When sufficient SO3 is present, MgO can be sulphated to MgSO4, which can
then react with V2O5 to from magnesium pyrovanadate which may be molten on the surface
boiler tuber and turbine blades (3).
MgSO4 + V2O5 2MgO.V2O5+ SO3 …………..………(2)
Thus, corrosion control in low grade or residual fuel oils is modified by the presence
of (SO3) (13). Blauenstein(14) injected dispersed magnesia additive and could gain benefits on a
300 MW oil-fired boiler such as improved combustion, reduction in total particulate
emissions and reduction in metallic corrosion as indicated by higher pH ash and confirmed by
iron determinations on the ash. An ideal additive should be miscible with fuel oil and
improve combustion conditions, especially atomization.
Barbooti et al. studied the inhibitive action of magnesium oxide and magnesium
sulphate (15) on the hot ash corrosion by heating alloy specimens in an electrical furnace and
following the inhibition by weight loss and chemical analysis of the scale. Nishikawa et al (16)
have studied the effect of Mg-Additive against high temperature fouling and corrosion. When
Mg was added, weight loss due to high temperature corrosion was reduced to about equal
level of corrosion by clean kerosene firing in the temperature range below 700C.

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The present work is a dynamic study of the action of magnesium hydroxide, Mg(OH)2
as an inhibitor of hot ash corrosion using a pilot scale kerosene fired furnace.
EXPERIMENTAL WORK
Materials and Chemicals
Three alloys were selected from those used in boilers including: SA 178A, 209 T1
and 213 T11 (water wall tubes and superheater tubes) from South-Baghdad Power Station.
The chemical composition of the alloy used in this work is shown in Table 1(17). Magnesium
hydroxide was supplied by a local factory, with a purity of 98.5%.
Heating Furnace
A kerosene fuelled furnace was designed especially for this study with ceramic shelves.
Fig. 1 shows the heating chamber during work, where the shelves on which specimens are
placed are shown.
Procedure Work
The Specimens Preparation
The specimens were cut from the pipes into rectangular pieces (5x10x20 mm) (W x L
x T) and mechanically polished with emery paper (100, 320, 600 and 1000) under running tap
water and rinsed with distilled water, benzene, then these specimens were dried and left in a
vacuum desiccators and weighed.
The vanadic slag chosen for this work was based on 67 wt% (V2O5) and 33 wt%
(Na2SO4). This mixture was chosen because it has been shown to be the most representative
corrosive simulated by other workers (18, 19). Weighed proportions of V2O5 and Na2SO4 in the
ratio 3:1 were mixed and ground in an agate mortar for 15 minutes. The slag mixture was
than stored in desiccators until required for use.
About 2.09 g of Mg(OH)2 was mixed with and 10.0 g synthetic ash and homogenized
with 3 mls of acetone. With the aid of a syringe the mixture was applied onto the surface of
the cleaned specimens to give a coating of 1 mole Mg(OH)2 : 1 mole ash. The tests were
carried out at various time intervals (2, 4, 6, 8 and 10 h) to study the normal oxidation at
different temperature (550, 650, 750, 850 and 950 ˚C). Constant time tests involved heating at
the specified temperatures for 4 h. At the end of the run, the furnace is switched off and
samples are taken out after 24 h. The specimens are dipped in caustic soda solution

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containing zinc dust (20% NaOH + 200g Zn/L.), at 60˚C for five minutes, and abraded with
emery paper grades (100, 320, 600 and 1000) respectively under running tap water, then
rinsed with water and kept over silica gel for one hour, and finally weighed to the fourth
decimal.
ANALYSIS
The specimens exposed were examined in detail, particular notice being given to the
color and appearance of corrosion products and the extent of spallation. The X-ray diffraction
technique was used to identify the scale compounds and the corrosion products formed in this
work using Phillips X-ray Difractometer, Type PW1050 Holland with iron target to produce
an x-ray beam of wavelength of Fe-kα at 1.93 Å using a tube current of 20 mA. and a
voltage of 40KV. The speed scans of [2°(20)/1cm]. Reference was made to the ASTM card
Index.
RESULTS AND DISCUSSION
Effect of Vanadic Slag
Fig. 2 shows the dependence of weight gain with temperature after 4 h exposures time.
The rate of oxidation is accelerated in the presence of vanadic slag mixture in comparison
with uncoated specimens. Further, the application of this slag on the specimen surface
resulted in increased corrosion rate with increasing temperature (550-950 oC). The scale
formed after the thermal treatment is sticky and metallic in color. The X-ray diffraction
analysis indicated the formation of sodium vanadate which is the most important aggressive
species in the (Na-V-O) system. This product became appreciable after the melting of the
eutectic mixture and increase with temperature. Therefore, Na2SO4, which has no individual
aggressive behavior towards the metal, facilitates the low temperature melting of the ash and
initiates the formation of sodium vanadate, which attacks the metal surfaces(4).
At 850˚ C, the weight gain for (SA-178A) in a (V2O5 : Na2SO4) slag is 0.16 kg/m2
compared with 0.013 kg/m2 for normal combustion for the non-coated specimens. This
indicates high corrosion behavior occurring at (850 ˚C) because (V2O5 – Na2SO4) system
melts at about (650 ˚C) and forms highly corrosive sodium vanadates (18, 19). For example,
after (4h) and (850˚C), the average weight gain for (213 T1) in a V2O5:Na2SO4 mixture is
0.14 kg/m2 compared with 0.011 kg/m2 for specimen non-coated.

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The relation between the heating intervals and the weight gain at different
temperatures is typically shown in Figs 3 and 4. It is clear that the increase in time, leads to
increase in weight gain and hence vanadic slags highly accelerated the oxidation of the
alloys. Much of the weight gain occurred within the high temperature regions (750, 850 and
950 ˚C ) because many sodium-vanadium bronzes such NaVO3 , Na2O.V2O5, Na2O.3V2O5,
Na2O.6V2O5 and Na2O.V2O4.5V2O5 are predominant above (650 ˚C). These catastrophically
oxidize the alloy components acting as oxygen carriers, metal oxide distorts, or dissolving
agents of the protective oxide layer, and this leads to an accelerated increase in weight gain
with temperature rise( )19 . The figures clearly show that the increase in exposure time gives
increase in weight gain for all specimens coated with slag and those non-coated.
Effect of MG(OH)2 Addition
Figs. 5 and 6 show the weight loss of the three alloys specimens coated with Mg(OH )2
and slag at mole ratio of 1:1 , 2:1, and 3:1, respectively. Clear reduction in the degree of
corrosion with increasing Mg(OH)2 content can be seen. The color of the scale changed from
brown-yellow to red. The best ratio from Mg(OH)2: Ash is 3:1 because the mixture on the
surface of specimens was become totally from the rest of the specimens where the coating
turned into a white powder that is easily removed by simple tapping of the specimen. This
ensures that with a magnesium addition three times the amount of vanadium, a high melting
material is produced (20, 21).
The results are given in Tables 3-7. The optimum Mg(OH)2:Ash ratio is 3:1, which
gave inhibition efficiency of 85% at 550°C. The results indicate that the inhibition efficiency
increases with temperature decrease. The best value is obtained at a temperature of 550 ˚C.
X-RAY DIFFRACTION ANALYSIS
For (SA-178A) alloy, the constituents of the coating or the scales of the corroded
specimens were identified by X-ray diffraction analysis. Fig. 7 shows the diffraction pattern
of the scale resulted from the synthetic ash after heating at (750°C) for (4h). The main peaks
of sodium vanadates NaVO3 at 2.799Å and α-NaVO3 at 2.097 Å could be identified together
with ferric oxide at 3.66 Å. This is an indication of the role of molten sodium vanadate on
introducing oxygen to react with the iron surface so that it catalyzed the oxidation of the
metal(22). Furthermore, the in situ formed oxide dissolves in the molten layer of the ash
compounds and causes the gradual depletion of iron.

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For the 209 T1 alloy the effect of ash on the iron surface confirmed the oxidation and
dissolution of Fe2O3 in the molten scale in addition to the formation of several types of
sodium vanadates. The sodium- vanadium bronzes, namely: NaV3O8 at 6.508, 3.58 and
2.593Å, Na2O.V2O4.5V2O5 at 3.338 Å, Na4V2O7 at 4.08 and 2.298 Å. The thermal treatment
also resulted in the formation of vanadyl sulfate (VOSO4 and its main peaks at 5.017, 2.107
and 1.981 Å predominate at the diffraction pattern (Fig.8). Similarly residual sodium sulfate
could be identified, Na2SO4 (1.572 Å) and iron oxide (Fe2O3) at 3.769 Å.
With the introduction of Mg(OH)2 and ash, at 1:1 mole ratio, the diffraction pattern
indicated a clear diminishing of the main peaks of sodium vanadates (mainly the 3. 477 Å
peak) accompanied by the appearance of same new peak related to magnesium oxide (2.105
Å) and magnesium vanadate (2.677 and 1.744 Å). However magnesium sulfate also showed
up at 1.972 Å. Thus, magnesium competed well with sodium to abstract the vanadium and
consequently prevented its aggressive effect towards iron and other constituents of the SA-
178A alloy.
Further increase of Mg(OH)2 up to (2: 1) confirmed the inhibition efficiency where the
diffraction pattern was simpler than that related to the sodium scale since no sign for sodium
vanadate could be identified regarding the 213-T11 alloy. Magnesium vanadate Mg3V2O8
was a major constituent and the peaks related to it could well be resolved (3.38, 3.28 and
3.026 Å). A
gain, MgO was present in the studied sample (2.10 Å).
To ensure better corrosion prevention, a third additive to ash mixture was used which is
the 3:1 (Mg(OH)2:Ash) . The X-ray diffraction–patterns of the coating of the three alloys
heated for 4 h at 850 C˚ can be seen in Fig. 8. It is apparent that MgO peak predominates at
the three samples indicating that no further increase in Mg(OH)2 content is necessary.
Besides, the patterns did not show significant signs for the sodium vanadates, i. e. any chance
for the vanadium to from corrosive material with sodium.
Consequently, magnesium vanadates existed in the three samples as indicated by the
main diffraction peaks at 5.78, 3.20, 3.043, 3.036, 2.618, 2.582, 1.744, 1.743 and 1.701 Å.
Thus, the inclusion of magnesium in the coating completely inhibited the formation of the
aggressive sodium vanadyl vanadates and formation of the high melting species, the
magnesium vanadate instead (16, 22 and 23).

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CONCLUSIONS
Magnesium hydroxide can be successfully used for the prevention of hot ash corrosion
of steel structures of power generation stations. The optimum efficiency of inhibition could
be attained at 3:1 molar mixture of Mg(OH)2: synthetic ash. The study of inhibition can well
be carried out in a kerosene fired furnace to simulate the dynamic nature of the process. X-
ray diffraction analysis indicated complete diminishing of the formation of the aggressive
sodium vanadates and the formation of the high melting magnesium vanadate which can be
easily removed from the surface of the steel pipes and other parts of the boilers. It is apparent
that MgO peak predominates at the three samples indicating that no further increase in
Mg(OH)2 content is necessary. Besides, the patterns did not show significant signs for the
sodium vanadates, i. e. any chance for the vanadium to from corrosive material with sodium.
REFERENCES
1. H. Singh, D. Puri and S. Prakash, “An overview of Na2SO4 and/or V2O5 induced hot
corrosion of Fe- and Ni-based superalloys, Rev. Adv. Mater. Sci. 16 (2007) 27-50.
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3. D.M. Johnson, D.P. Whittle and J. Stringer, Corrosion Sci., 721 (1975) 15.
4. N. Birks, G.H. Meier and F. S. Pettit, “Introduction to the High Temperature
Oxidation of Metals”, 2nd Ed., Cambridge, 2006.
5. P.G. Kristensen and A. Bentkarll, Combust. Sci. Technol., 157 (2000) 263.
6. K. B. Alexander, K. PruBner, P.Y. Hou and P.T. Tortorelli, in “Microscopy of
Oxidation”,. J.B. Newcomb and J.A. Little Eds., The Institute of Metals. 1997, Chap. 3,
pp 246-255.
7. K. Page, and R. J. Taylor, in A. B. Hart, and A.J. Cutler, Eds.,“ Deposition and
Corrosion in Gas Turbine", Applied Science, London, 1973, P 350.
8. M. E. EL- Dahshan, Proc. 1st Arab Conf. Corrosion, Kuwait, 1987, PP 347-361.
9. R.A Rapp, Pure and Appl. Chem., , 62 (1990), No. 1.
10. Petrolite Corp., Tretolite Div., “Fuel Addition”, Petrolite. 1986.
11. J. R. Rhys-Jones, T.N. Nicholils and P. Hancock, P., Corrosion Sci., , 23 (1983) 39-44.
12. J. Stringer, “High Temperature Corrosion Issues in Energy-Related Systems”, Materials
Research, , 4l7 (2004) 1-9.
13. P. Hancock, Corrosion Sci., , 23 (1982) No.51.

First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010
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14. E. Blauenstein, Engineering found. Conf., New England College, New Hampshire,
July-26 , 1977.
15. M.M. Barbooti, S.H. AL-Madfai and H. J. Nassonri, Thermochim. Acta., 1988, 126,
34-49.
16. E. Nishikawa, M. Kaji and S. Ishigai, Proc. ASME, JSME Therm. Eng. Conf., 1 (1983)
545-52.
17. R. Francois, L. Thiorry and L. Benoit, "Piping Equipment / Materials Petrole", Trouvay
and Cavrin, API, ASTM, ASME Standard, 1998.
18. H.C. Child, "The Effect of composition of Gas Turbine Alloys on Resistance of
Scalling and Vanadium Pentoxide", J.I.S.I., 1985.
19. M. M. Barbooti, Proc. 1st. Conf. Chem. Petrochem. Ind. (Chem-Arab), Beirut, 2001, 10-
14 Jan.,
20. R.C. Kerby and J.R. Wilson, Engineering for Power, ASME-Trans., Vol. 1, 1973.
21. A.V. Malik, and S. Ahmed, British Corrosion J., 20 (1985) 181.
22. J. A. Fellows, Metals Handbook, "Fractograph and Atlas of Fractographs", ASM
Handbook Committee, 8th Edition, 1974, Vol.9.
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Fig.(1): Furnace at Work Showing the fire front, burning chamber, door, brick in contact with
thermocouples for wall temperature measurement.

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Fig.(2): Effect of heating Temperature and Weight Gain for 209 T1 Specimens at four hours
of exposure.
0
0.05
0.1
0 2 4 6 8 10 12
Time (h)
Fig. (3): Effect of exposure Time on Weight Gain for SA-178A Specimens at 550oC.
0
0.05
0.1
0.15
0.2
0 2 4 6 8 10 12
Fig.(4): Effect of exposure Time on Weight Gain for (213 T11) Specimens at 950 oC.
0
0.05
0.1
0.15
0.2
400 500 600 700 800 900 1000
Oxidation

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0
0.05
0.1
400 500 600 700 800 900 1000
Temperature
Weight Loss kg/m
Fig. (5): Effect of Temperature on weight loss at various Ratios of Mg(OH)2:Ash for SA-
178A Specimens at 4h.
0
0.05
0.1
400 500 600 700 800 900 1000
Fig. (6): Effect of Temperature on weight loss at various Ratio of Mg(OH)2:Ash. For (209
T1) Specimens at (4 h).

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Fig. (7): X-ray Diffraction Analysis of Deposits on SA-178 Specimen Coated with Ash ,
Heated at 750˚C and 4h.
Fig.(8): X-ray Diffraction Pattern of Deposits on 213 T11 Specimen Coated with [3:1]
Mg(OH)2 :Ash, Heated at 750˚C for 4h.

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Table (1):Chemical Composition of Alloys (17).
Components
SA-178A% 209 T1% 213 T11%
C 0.06-0.18 0.1-0.2 0.08-0.15
Mn 0.27-0.73 0.3-0.8 0.3-0.6
Pmax. 0.035 0.025 0.025
S max. 0.035 0.025 0.025
Fe Remain Remain Remain
Si 0.1-0.5 0.5-1
Mo 0.044-0.65 0.44-0.65
Cr 1-1.5
Table(2): Weight Losses in the Presence of Mg(OH)2 for (SA-178) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 --0.06 --0.078 --0.14 --0.16 --0.17
1:1 0.02 0.037 0.065 0.07 0.072
2:1 0.016 0.03 0.056 0.063 0.065
3:1 0.009 0.024 0.04 0.044 0.052
Table(3): Inhibition Efficiency in the Presence of Mg(OH)2 for (SA-178) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 -- -- -- -- --
1:1 66 51 53 56 57
2:1 73 61 60 60 62
3:1 85 69 71 69 69
a Inhibition efficiency = [ (wo-wi) / wo ] * 100 %
Where: Wo = weight loss in the presence of [Ash]
Wi = weight loss in the presence of [Ash + Mg (OH)2 ]

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Table(4): Weight Losses in the Presence of Mg(OH)2 for (209 T1) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 0.056 0.07 0.126 0.144 0.153
1:1 0.018 0.0344 0.058 0.063 0.065
2:1 0.0144 0.027 0.05 0.057 0.058
3:1 0.0081 0.0216 0.036 0.0441 0.048
Table(5): Inhibition Efficiency in the Presence of Mg(OH)2 for (209 T1) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 -- -- -- -- --
1:1 68 51 54 56 57
2:1 74 61 60 60 62
3:1 85 69 71 69 68
Table (6): Weight Losses in the Presence of Mg(OH)2 for (213 T11) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 0.053 0.068 0.123 0.140 0.149
1:1 0.0176 0.0325 0.057 0.0616 0.063
2:1 0.014 0.026 0.044 0.055 0.057
3:1 0.0079 0.021 0.035 0.038 0.045
Table (7): Inhibition Efficiency in the Presence of Mg(OH)2 for (213 T11) Specimens.
Temperature, oC. Mg(OH)2:Ash
550 650 750 850 950
0:1 -- -- -- -- --
1:1 67 52 55 55 58
2:1 73 62 60 61 62
3:1 85 69 72 72 70

First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010
THE INHIBITIVE ACTION OF MAGNESIUM HYDROXIDE ON HOT ASH CORROSION OF
STAINLESS STEEL IN A KEROSENE FIRED FURNACE
Diyala Journal of Engineering Sciences – Special Issue
405
ﻰﻠﻋ موﯾﺳﯾﻧﻐﻣﻟا دﯾﺳﻛوردﯾﻬﻟ طﺑﺛﻣﻟا رﯾﺛﺄﺗﻟا دﺎﻣرﻠﻟ ﺔﯾﻠﻛﺎﺗﻟا ﺔﯾﻠﺑﺎﻘﻟا دﯾدﺣﻠﻟ نﺧﺎﺳﻟا
قرﺣ نارﻓأ ﻲﻓ نوﻠﻐﻣﻟا نﯾﺳورﯾﻛﻟا
ﺔﺻﻼﺧﻟا
ﺔــﺳارد مــﺗ ثــﺣﺑﻟا اذــﻫ ﻲــﻓ رﯾﺛﺄــﺗﻟا ﺔــﯾﻠﺑﺎﻗ ﻰــﻠﻋ موﯾﺳــﯾﻧﻐﻣﻟا دﯾﺳــﻛوﻻ طﺑــﺛﻣﻟا لــﻛﺂﺗﻟا ﻲــﻓ دــﯾدﺣﻟا ﻰــﻠﻋ نﺧﺎﺳــﻟا دﺎــﻣرﻠﻟ
مادﺧﺗﺳﺎﺑ ﺔﯾﺋﺎﺑرﻬﻛﻟا ﺔﻗﺎطﻟا دﯾﻟوﺗ تﺎطﺣﻣنارﻓأ نﯾﺳورﯾﻛﻟا قرﺣ ﺔطﺳاوﺑ لﻣﻌﺗ .
ثﻼــﺛ مادﺧﺗــﺳا مــﺗعاوــﻧأ كﺋﺎﺑﺳــﻟا نــﻣ )213 T11 209 T1,SA178A,( ةدوــﺟوﻣﻟا ﻩﺎــﯾﻣﻟا بــﯾﺑﺎﻧا ناردــﺟ نــﻣ ترﺿــﺣ
ءﺎﺑرﻬﻛﻟا دﯾﻟوﺗ ﺔطﺣﻣﺑ.
ﺎــــــــــﻬﯾﻠﻋ جذﺎــــــــــﻣﻧﻟا ﻊــــــــــﺿوﻟ فوــــــــــﻓر ﻰــــــــــﻠﻋ نﯾﺧﺳــــــــــﺗﻟا نرــــــــــﻓ يوــــــــــﺗﺣﯾ . موﯾﺳــــــــــﯾﻧﻐﻣﻟا دﯾﺳــــــــــﻛوردﯾﻫ جزــــــــــﻣ مــــــــــﺗ ثــــــــــﯾﺣ
ﻊﻣ)V2O5,33%Na2SO4
67% ( ﺔﯾﻟوﻣ بﺳﻧﺑ)1:1,1:2,1:3 (ﯾظﻧﻟا جذﺎﻣﻧﻟا حوطﺳ ﻰﻠﻋ ﻊﺿوﺗﻟ ﻲﻟاوﺗﻟا ﻰﻠﻋﺔﻔ.
ﺔـﻔﻠﺗﺧﻣ ﺔـﯾﻧﻣز تارـﺗﻔﻟو تﺎﻋﺎـﺳ ﺔـﻌﺑرا رﺎـﺑﺗﺧﻻا ةرـﺗﻓ ﻊـﺿوﺑ ﺔﺳاردﻟا تﻣﺗ )2 – 10تﺎﻋﺎـﺳ ( ﺔـﺳاردﻟرﯾﺛﺄـﺗ ةدﺳـﻛﻻا
ﺔﻔﻠﺗﺧﻣ ةرارﺣ تﺎﺟردﻟ)550-950ﺔﯾوﺋﻣ ﺔﺟرد .( ةدﺎﯾزﻟ ﺔﺟﯾﺗﻧو موﯾدﺎﻧﻔﻟا بﺋاوﺷ دوﺟوﺑ دادزا دﻗ ةدﺳﻛﻻا لدﻌﻣ نا دﺟو دﻗو
ةرارﺣﻟا تﺎﺟرد.
ﺔــﯾﻧﻘﺗ تﻣدﺧﺗـﺳا (X ray) نوــﻛﺗ ﺔــﺳاردﻟ Na2SO4,VOSO4,Na4V2O7,Na2O.V2O4.5V2O5,Fe2O3).( دــﻗو
موﯾﺳﯾﻧﻐﻣﻟا دﯾﺳﻛوا ةدﺎﯾزﺑ لﻛﺎﺗﻟا لدﻌﻣ ضﺎﻔﺧﻧا روﻬظ كﺋﺎﺑﺳ ثﻼﺛﻟ نزوﻟا نادﻘﻓ رﻬظ. ترﻬظأ نا ﺞﺋﺎﺗﻧﻟا لﺿﻓأ لﯾﻠﻘﺗﻟ ﺔﺑﺳﻧ رﯾﺛﺄﺗ لﻛﺂﺗﻟا ﺔﯾﻟوﻣﻟا ﺔﺑﺳﻧﻟا ﻊﻣ 3:1 ﻲﺗﻟاو تطﻋأ رادﻘﻣﺑ ةءﺎﻔﻛ 85 %ﺟردﺑو ﺔ
ةرارﺣ550ﺔﯾوﺋﻣ ﺔﺟرد . دﺎﻣر ﻊﻣ موﯾﺳﯾﻧﻐﻣﻟا دﯾﺳﻛوردﯾﻫ روﻬظو ةرارﺣﻟا ﺔﺟرد ضﺎﻔﺧﻧﺎﺑ دادزﺗ ﺔﺑﺳﻧﻟا ﻩذﻫ ناوMg3V2O8
موﯾﺳﯾﻧﻐﻣﻟا دﯾﺳﻛوا نﻣ لﯾﻠﻗو .
د.ﻲﺗوﺑرﺑ دوﻣﺣﻣ د. نﯾدﻟا ءﺎﻔﺻ ﷲادﺑﻋﻲﻣﯾﻌﻧﻟا د.ﻲﻧﺎطﻠﺳﻟا لﯾطﻧﻓ مظﺎﻛ
مدﻗا ثﺣﺎﺑ ذﺎﺗﺳأ سردﻣ
مﺳﻗﺳدﻧﻬﻟاﺔﯾوﺎﯾﻣﯾﻛﻟا ﺔ-ﻌﻣﺎﺟﻟاﺔ
ﯾﺟوﻟوﻧﻛﺗﻟا
ﺔ
مﺳﻗﻧﻬﻟاﺳدﺔﯾوﺎﯾﻣﯾﻛﻟا ﺔ-ﻌﻣﺎﺟﺔ
لﺑﺎﺑ