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@ CHIYODA CHEMICAL ENGINEERING & CONSTRUCTION CO., LTD.
P. 0. Box 10 Tsurumi, Yokohama, Japan
IN5 19 AS CATALYST TUBE MATERIA
TAKA0 KAWAl LElF RUMP KATSUAKI TAKEMURA BENNY DANIELSEN
TOSHIKAZU SHlBASAKl JOHANNES WRISBERG of of
Chiyoda Chemical Engineering Holdor Tops#e A/S & Construction Co., Ltd.
For The 1982 Ammonia Symposium a t 10s Angeles 14-18 November
INTRODUCTION
A t San Francisco i n 1979 and a t the Montreal meeting in 1981, we presented
metallurgical and mechanical properties of HK40 material based on long-term
creep rupture t e s t s and the resu l t s of destructive inspections on used
ca ta lys t tubes ( I ) , ( 2 ) . We also suggested selecting stronger and more
duc t i le al loys f o r the ca ta lys t tube material ra ther than the t radi t ional
HK40, i.e. a l loys developed from HK40 such as the IN519 (24Ni/24Cr Nb),
Hika and BST al loys .
Haldor Topsbe A/S and Chiyoda Chemical Engineering & Construction Co., Ltd.
have for the past e ight years specified IN519 f o r ca ta lys t tubes as being
preferable t o HK40, both f o r new ins t a l l a t i ons and f o r retubing exis t ing
reformers. Today, 3,400 s e t s of IN519 ca t a lys t tubes are in service f o r 30
HTAS reformers without any reported problems.
This paper i s concerned w i t h technical and economic improvements i n
reformers through the u t i l i za t ion of IN519 as ca ta lys t tube material. I t
also deals w i t h the proven superior charac te r i s t ics of IN519 based on
metallurgical t e s t s on aged specimens and f i v e sample ca ta lys t tubes which
had been removed from three reformers a f t e r one, three, and six years of
service.
DESIGN OF REFORMERS WITH IN519
The creep damage i n ca ta lys t tubes i s accelerated by thermal s t resses due
t o temperature gradients i n the wall , especia l ly repeated high s t r e s se s from shutdown and s tar t -up. Certain properties in materials a re desi rable
a s such properties tend t o reduce o r prevent creep damage. Increasingly,
the following desi rable properties have been recognized:
(1) High rupture strength which permits th inner walls , result ing i n a decrease in tube-metal temperature and thermal s t r e s s .
(2 ) Higher rupture d u c t i l i t y which relaxes the thermal s t resses .
Several a l loys have been developed w i t h a 20 t o 30 percent higher creep
rupture strength a s well a s higher duc t i l i t y than HK40. The chemical
compositions of these a l loys a r e compared in Table 1.
IN519 was selected from these a l loys mainly because actual plant experience
had been reported and IN519 tubes were comparable t o HK40 in price since
they contain only 24 percent nickel. IN519 was developed from HK40 by INCO
Europe Limited i n the ear ly 1960's and i n 1968 the f i r s t IN519 ca ta lys t
tubes were applied in a commercial reformer furnace.
In order t o examine performance under process conditions and t o determine
economic f e a s i b i l i t y , many reformers were designed t o compare two possible
ca ta lys t tube mater ia ls , HK40 and IN519. Table 2 shows the data of s i x
selected reformers of d i f fe ren t design.
As a basis f o r t h i s comparison, the same production r a t e corresponding t o 1,000 MTPD ammonia has been selected f o r the design of reformer furnaces
assuming the following conditions.
( 1 ) Feed Stock : Natural Gas CH4 : 96.5 vol. %
C2H6 : 3.0 vol. %
C 3 H 8 : 0.5 v o l . %
(2 ) Reformer Type : Topsde's Radiant Wall Type
Case 1 i s a base case w i t h HK40 re f lec t ing what may be considered as f a i r l y
conventional reformer operating conditions using a steam t o carbon r a t i o of 2 3.6 and an average internal heat f lux of approximately 70,000 Kcallm hr.
Cases 2,3 and 4 w i t h IN513 a l s o possess a steam t o carbon r a t i o o f 3.6 and
are designed t o main ta in some cond i t i ons f o r comparison w i t h t h e base case.
As seen i n Table 2, f o r a l l IN519 cases, the maximum tube w a l l temperatures
were lowered and t h e i n n e r tube diameters were increased.
I n Case 2 w i t h t h e same number o f c a t a l y s t tubes as i n Case 1, t h e requ i red
heated l e n g t h was shortened about 5 percent and t h e pressure drop through 2 the c a t a l y s t bed was decreased 0.5 Kg/cm . I n add i t i on , Case 2 had t h e
same peak heat f l u x as Case 1.
Case 3 was ab le t o reduce t h e c a t a l y s t tube number about 4 %, w h i l e
ma in ta in ing t h e same heated l eng th and t h e average heat f l u x .
The b igges t reduc t i on i n t h e c a t a l y s t tube number, about 9 %, was obta ined
i n Case 4, where t h e heated l eng th and t h e pressure drop were kept t h e
same as i n Case 1.
Cases 5 and 6 i n Table 2 a l so used IN519 tube ma te r ia l , these cases
demonstrate c h a r a c t e r i s t i c data f o r an ammonia p l a n t w i t h increased heat
f l u x and a steam t o carbon r a t i o o f 3.0 i ns tead o f 3.6. The decrease i n
t h e steam t o carbon r a t i o requ i res an increase i n t h e e x i t gas temperature
o f about 20°C. Both t h i s change and increase heat f l e x y i e l d h igher tube
w a l l temperature. Though t h e ou te r tube diameters had t o be decreased t o
pro long t h e tube l i f e , i t was poss ib le t o o b t a i n ex tens ive savings and keep
acceptable tube w a l l th ickness due t o t h e h igher s t reng th p rope r t i es o f
IN519.
Thus, by u t i l i z i n g IN519 c a t a l y s t tubes i ns tead o f HK40 tubes, t echn ica l
and economic improvements have been made i n t h e design o f reformer
furnaces. Through r e t u r b i n g p r o j e c t s , we have a l s o adapted e x i s t i n g
reformers t o be i n s t a l l e d w i t h IN519 c a t a l y s t tubes apply ing updated
engineer ing and design technology.
The aforementioned m o d i f i c a t i o n s have been repo r ted (3). One such
m o d i f i c a t i o n took p lace on a 1,000 MTPD ammonia p l a n t a f t e r 8 years o f
operat ion. By r e p l a c i n g HK40 ma te r ia l t o IN519 and by rearrangement o f t h e
tube layout from a staggered row to a s ingle snaked row, the number of
ca ta lys t tubes was reduced from 300 t o 204, a reduction of 96, with no
change in the reformer furnace i t s e l f nor the process conditions. Once
implemented, these modifications were proven successful during actual plant operation.
METALLURGICAL EXAMINATION O F IN519 CATALYST TUBES
I t i s necessary t o examine the cha rac t e r i s t i c s of materials which have been
used f o r a long time o r have been aged f o r a long time. Such data are compiled in order t o predict the degradation of ca ta lys t tubes and to
estimate the tube \ l ives in the actual plants. Although data on aged
materials are avai lable through laboratory t e s t s , these data a re not
necessarily very accurate nor r e l i ab l e in estimating the degradation of
ca ta lys t tubes in actual plants because the time fo r aging i s simply not
long enough. As a r e s u l t , examinations were conducted t o confirm the
properties of the IN519 material a f t e r long term use.
(1) Aging Tests:
Specimens were exposed t o f i v e d i f fe ren t environments in the steam
reformer furnaces f o r as long a s three years and the specimens
were subjected t o metallurgical t e s t s .
( 2 ) Examination of Used Catalyst Tubes:
Metallurgical examinations were conducted on f i v e used ca ta lys t
tubes which were taken as sample tubes from two hydrogen plants and an ammonia plant.
RESULTS OF AGING TESTS
The chemical composition of the spun c a s t tubes used f o r the aging t e s t i s
shown in Table 3 . The IN519 and HK40 t e s t coupons and t h e i r weld jo in t s
were exposed t o f i v e d i f fe ren t environments including two t ransfe r l ines
f o r the reformed gas, the e x i t of a secondary reformer and two i n l e t s of convection zones of reformer furnaces, a s shown i n Table 4.
Metallurgical and mechanical examinations were conducted a f t e r aging of
one, two and three years. To compare the aging conditions, the
Larson-Miller Parameter, L.M.P.=T(log t +16)x10-~, was used as the aging
parameter. These aging parameters for each t e s t coupon a re a lso l i s t e d i n
Table 4.
Microscopic Examinations
Photograph 1 shows the microstructures of IN519 and HK40 i n as-cast
condition. Photographs 2, 3 and 4 show the microstructures of aged
materials. When the aging parameter was low such as 20.3 and 21.0 and
the tubes were aged a t around 750°C, many f ine secondary carbides
precipitated a t the interdendri t ic region. Small amounts of sigma
phases were found i n specimens w i t h an aging parameter of 20.3.
As the aging parameter increased, the primary and secondary carbides
coarsened. The amount of secondary carbides and sigma phases was l e s s
than those i n HK40. The coarsening of carbides i n IN519 seemed t o
occur more quickly than in HK40 as seen i n Photographs 3 and 4.
Tension Tests a t Room Temperature
Figures 1 , 2 and 3 show the resu l t s of the tension t e s t s a t room
temperature a f t e r aging. The changes i n the t ens i l e strengths of the IN519 tubes and weld jo in t s a f t e r aging were less than those of HK40.
The behavior of the 0.2 % proof s t resses were ra ther s imilar t o those
of HK40. Although the data on elongation and reduction of area of IN519 were widely spread when plotted , t h e i r values were higher than
those f o r HK40 a t higher aging parameters.
Impact Tests
Figure 4 shows the comparison of Charpy impact values a t room
temperature on aged IN519 and HK40. The change of the impact values
of the IN519 and HK40 by aging corresponded t o the change i n
elongations a t room temperature tension t e s t s .
(4 ) Hardness Tests
F igure 5 shows t h e change i n hardness a f t e r aging. The hardness
showed t h e maximum value a t the aging parameter around 20.5 t o 21.5
and decreased as t h e parameter increased. This behavior was s i m i l a r
t o t h a t o f HK40.
1 (5) Creep Rupture Tests
To con f i rm the pub l isned rup tu re data, creep rup tu re t e s t s were
conducted on t h e IN519 spun cas t tubes and t h e weld j o i n t s as shown i n
F igure 6. The data taken on the new IN519 spun cas t tubes reasonably
fo l lowed t h e mean values o f t h e master curve presented by INCO (4) .
Although almost a l l data f e l l w i t h i n t h e s c a t t e r range, t h e r u p t u r e
st rengths o f weld j o i n t s were somewhat lower than those o f t h e base
metals.
Creep rup tu re t e s t s were a l so done on t h e aged specimens.
F igure 7 shows the r e s u l t s of t h e creep rup tu re t e s t s on t h e base
metals and weld j o i n t s which were aged a t approximately 920°C f o r two
years (aging parameter : 24.1). The rup tu re st rengths decreased
somewhat due t o t h e change o f mic ros t ruc tures by aging. However, as
shown i n F igu re 8, t h e rup tu re s t rengths o f 1,000 hours o f IN519 base
ma te r ia l as w e l l as weld j o i n t s , were s t i l l h i ghe r than those of HK40
f o r each aging cond i t i on .
F igure 9 shows the comparision o f t h e rup tu re d u c t i l i t i e s o f aged
IN519 and HK40. The rup tu re d u c t i l i t i e s decreased as the r u p t u r e t ime
increased f o r bo th ma te r ia l s . The minimum value o f IN519 was h ighe r
than t h a t o f HK40 and was almost the same as the maximum value o f
HK4O.
EXAMINATION ON USED CATALYST TUBES
F i v e IN519 c a t a l y s t tubes have been i nves t i ga ted des t ruc t i ve l y . The
ope ra t i ng cond i t ions o f these c a t a l y s t tubes are shown i n Table 5. Test
i tems f o r examination o f each c a t a l y s t tube are l i s t e d i n Table 6. The
original location of t e s t pieces used i n examinations are a lso shown i n
Table 6 f o r the case of the S4 ca ta lys t tube. The t e s t resu l t s a r e a s
follows.
(1) Nondestructive Tests
To inspect deformation due to creep, dimensional checks were done. No
meaningful deformation was observed f o r a l l tubes. Radiographic Tests
(RT) and Dye-Penetrant Tests (PT) conducted on both the outer and
inner surfaces f o r every weld zone, indicated no f au l t s due t o creep
damage on a l l of the ca ta lys t tubes.
( 2 ) Tension Tests
Figures 10 and 11 show the summary of tension t e s t s a t room
temperature f o r a l l ca ta lys t tubes. The data a r e plotted along the
length coordination where "Location 0" means the i n l e t and "Location
100" re fe rs t o the ou t l e t of a ca ta lys t tube. The i n l e t of t he ca ta lys t tube o r so called "cold end" i s out of the furnace, and the
service temperature i s about 400-450°C. Since t h i s temperature is not
so high as t o age the heat res i s t ing al loy, the mechanical properties
of t h i s par t re ta in the as-cast condition.
Although change i n the t ens i l e strength along the length coordination
was d i f fe ren t from tube t o tube, the t ens i l e strengths tended t o
decrease a s the used period became longer as shown i n Figure 10.
Changes i n the 0.2 % proof s t resses a t room temperature were
re la t ive ly small f o r a l l sample tubes, as expected from the aging
t e s t .
Figure 11 shows the elongation a t room temperature. Generally, the
d u c t i l i t y was reduced greatly a t "Location 10" close t o the top of t h e
tubes, though changes i n the elongation along the tube length were
d i f fe ren t f o r each tube.
Tension t e s t s were a l so conducted a t 87loC and the r e su l t s a re shown
in Figures 12 and 13. The data on t ens i l e properties a t 871°C
indicated t h a t the range of these properties was not as g rea t as t h a t
shown by t e s t s conducted a t room temperature.
(3 ) Microscopic Examinations
To inspect the creep damage i n d e t a i l , microscopic examinations were
conducted on four longitudinal sections of every weld zone. No
f i s sures o r no aligned voids due t o creep were detected on a l l of the
specimens taken from every ca ta lys t tube.
Photograph 5 shows the microstructures of "Location 10" and "Location
70" of the S5 Tube which was used f o r s i x years. The service
temperature a t "Location 10" was lower than tha t of "Location 70".
The microstructure of "Location 10" showed many f i ne secondary
carbides and needlelike sigma phases. In "Location 70" the primary
carbides and the secondary carbides were coalesced and coarsened, and
the number of the secondary carbides was few.
Compared t o the microstructures of HK40 tubes shown in Photograph 6
which were exposed t o s imilar service conditions, the amount of
secondary carbides i n the microstructures of IN519 was l e s s and the
r a t e of coalescence seemed t o be f a s t e r i n IN519. A small amount of
blocky sigma phase was observed.
(4 ) Creep Rupture Tests
Creep rupture t e s t s were conducted on the specimens taken from the 53
tube which was used f o r three years. Test specimens were taken from
three par t s of the tube: one was from the cold end and the others were
one quar ter and two-thirds from the top of the tube, areas qf high
service temperature. Figure 14 shows the resu l t s . The specimens from
high temperature par t s showed somewhat lower rupture strengths than
those from the cold end.
DISCUSSION
(1) Mechanical Properties of Aged IN519 Material
1 ) Creep Rupture Properties
I t i s generally recognized t h a t creep rupture elongation as well
as creep rupture strength of the IN519 material i s higher than tha t of the HK40 material i n the as-cast condition. The same
relation was found t o be t rue of specimens which were aged for as
long a s three years , proving the superiori ty of IN519 over HK40 i n
the creep rupture strength and duc t i l i t y f o r long term use.
2 ) Ducti l i ty i n Tension Tests a t Room Temperature
The elongation and t h e reduction of area in tension t e s t s a t room
temperature of aged material are not the major parameters which
a f f ec t ca ta lys t tube l i f e . Materials having higher duc t i l i t y a t
room temperature a r e preferable f o r ca ta lys t tube use, because
duc t i le material i s more res i s tan t t o f a i l u r e caused by thermal
shock or sudden change of service temperature which might occur
during an emergency shut down.
The resu l t s of the tension t e s t s on the used IN519 ca ta lys t tubes
revealed t h a t the t ens i l e properties of each ca ta lys t tube was d i f fe ren t , especially the elongation values a t room temperature.
This variation i s assumed t o come from chemical composition and
production procedures. The e f fec t of chemical compositions on the
elongation i n the t e n s i l e t e s t s a t room temperature of the aged
IN519 material was analyzed.
Figures 15, 16 and 17 show the e f f ec t of carbon, s i l icon and
manganese, respectively, on the elongation a t room temperature.
In t h i s analysis, the data was divided in to three groups using the
service temperatures of the catalyst tube regardless of the used
periods. The f i r s t group contained data from the cold end, which nearly represented the properties of unused materials. The second
group consisted of data from "Location 5" t o "Location 30" whrrc
the service temperature was not as high as t h a t i n the thi rd
group. The t h i r d group inc luded data f rom "Locat ion 30" t o t h e < o u t l e t , where t h e se rv i ce temperature was highest. The e f f e c t o f
chemical composit ion on the e longat ion values o f unused mater ia l
was i n s i g n i f i c a n t as was revealed upon ana lys is . S i m i l a r
r e l a t i o n s h i p s demonstrat ing the e f f e c t s o f c e r t a i n elements on the
e longat ion were obta ined f o r the second and t h i r d groups and are
summarized as f o l l o w s :
O Carbon(Fig.15) and Niobium have no s i g n i f i c a n t e f f e c t .
O S i l i c o n ( F i g . l 6 ) , Phosphor, and S u l f u r have negat ive e f fec ts .
" Manganese(Fig. l 7 ) , N icke l and Chromium have p o s i t i v e e f f e c t s .
(2) Comparison o f IN519 and HK40 Cata l ys t Tubes on Creep Damage
Long i tud ina l creep damage i n t h e base metal o f HK40 c a t a l y s t tubes
which had been used as l o n g as several years was o f t e n reported. And
c i r cumfe ren t i a l creep damage a t t h e weld metals was a l s o observed on
the HK40 c a t a l y s t tubes which had been used beyond th ree years. These
cracks were caused by thermal s t ress due t o t h e temperature grad ien t
i n t h e wa l l .
However no such creep damage was observed i n the IN519 c a t a l y s t tubes
which had been used up t o s i x years. Th is was main ly a t t r i b u t e d t o
the h igher rup tu re s t r e n g t h and rup tu re d u c t i l i t y o f IN519.
CONCLUSION
Creep rupture strength and creep rupture duc t i l i t y of IN519 spun c a s t
material a r e confirmed t o be higher than those of HK40 material even a f t e r long time use.
Use of IN519 due t o increased rupture strength yields thinner wall
design and reduces thermal s t ress .
Suscept ibi l i ty t o creep damage of IN519 ca ta lys t tubes i s lower than
tha t of HK40 ca ta lys t tubes based on destructive examinations of IN519
ca ta lys t tubes indicating no tube damage a f t e r as much as s ix years
use.
The d u c t i l i t y of IN519 a f t e r aging i s affected different ly by chemical
compositions such as Si and Mn. Carbon have no s ign i f f ican t e f f e c t on
the duc t i l i t y .
By u t i l i z i n g IN519 as ca ta lys t tube material , the following technical
and economic advantages can be obtained:
" Decreased costs resultant of improved, compact reformer design
O Extended operating range
" Increased operating re1 iab i l i t y
O Lower fuel consumption
All these improvements were ver i f ied during actual commercial plant operations.
REFERENCE
T. Kawai, K. Takemura et al, "Effect of Macrostructure on Catalyst Tube Damage and Creep Rupture Properties of HK40t1, AIChE Ammonia Plant Safety, Vol. 22, pp. 119-30, 1980.
T. Kawai, T. Takemura et al, "Creep-Rupture Properties of HK40 Spun Cast Tubes", AIChE Plant/Operation Progress, Vol. 1 No.3, pp. 181-6, July 1982.
N. Moriya, T. Kawai & H. Uchida, "Technical and Economic Improvements from Catalyst Tube Modifications in Steam Reforming Plant", Bulletin of Arab Federation of Chemical Fertilizer Products, No. 67, pp. 15-24, May 1981.
INCO Europe Limited, INCO Data Books "IN519 Cast Chromium-Nickel-Niobium Heat Resisting Steel1', 1976.
i
c Table 1 Chemical Compositions of Catalyst Tube Alloys
Alloy Other
1 BST 25 20 0.45 0.6 Ti
Table 2 Comparison of Reformer Designs*
Case 1 2 3 4 5 6
Tube Material HK 40 IN 519 IN 519 IN 519 IN 519 IN 519
Number of Tubes 186 186 178 170 166 188
Max. Tube Wall Temp. 891 886 883 886 900 891 ("C)
Ave. Heat Flux 69,800 69,300 69,800 72,500 75,300 82,000 (Kcal/SMh)
Heated Length 11.5 - 11.0 11.5 11.5 12.2 12.1 (4
Pressure Drop.. .old 2.3 1.9 2.1 2.3 2.8 4.4 (Kg/SCM)
Outer Tube Diameter 152 152 152 152 142 115 (m)
Inner Tube Diameter 115 121 121 121 110 90 (mm)
* Boldface type indicates conditions matching Case 1
Table 3 Chemical Compositions o f Spun Cast Tubes Used f o r Aging Tests
T.C: Test Coupon
Table 4 Sumnary o f Aging Test Condit ions
T.L. : Transfer L i n e C.Z. : Convection Zone Bottom S.R. : O u t l e t o f Secondary Reformer A.P. : Aging Parameter, T(1og t + l 6 ) x l 0 - ~ , T(OK), t (hou r ) Temp.: (OC)
Photograph 1 Microstructures of IN519 and HK40 As-Cast Condition
(2) HK40
Photograph 2 Microstructures of IN519 and HK40 After Aging (A.P.=20.3)
Pho tog raph 3 M i c r o s t r u c t u r e s o f IN519 a n d HK40 After Aging (A.P.=22.7)
- 17 -
Photograph 4 M i c r o s t r u c t u r e s o f IN519 and HK40 A f t e r Aging (A.P.=24.1)
20 0 20 21 22 23 24
hging Parameter = T(log t +16)/1m
Fig. 2 comparison of Tensile Strengths at Room Temperature of
IN519 and HK40 Weld Joints After Aging
b Teat Coupon IN519 Oh B < 0 HK40 AD 7
Y 1 I 1
0 -
20 21 22 23 24
Aging Parameter = TUog t +16)/1000 Fig. 3 Comparison of Ductilities of Tension Test at Room Temperature
of IN519 and HK40 After Aging
I 1 I I
0 20 21 22 23 24
Aging Parameter = T(lag t +16)/1888
Fig. 4 Comparison of Charpy Impact Values at Room Temperature of
of IN519 and HK40 After Aging
Teet C o u p IN519 OA OC HKM VE
Aging Parameter = T (log t +I61 /I000
Fig. 5 Change in Vickers Hardness of IN519 and HK40 After Aging
Fig. 6 Results of Creep Rupture Tests on IN519 Spun Cast Tubes
17 18 19 20 21 22 23 24 25 26
L. M. P. = T (log t +16) /I000
Fig. 7 Results of Creep Rupture Tests on Base Metals and Weld Joints
of IN519 After Aging 2 years at 920°C
Aging Parameter = TClog t +16)/1000
7.0
G 6.0
E < 5 .0 -
6 m m " 4.0- PI L
-9 cn
Fig. 8 Comparison of 1,000 hour Rupture-Strengths of Aged IN519 and HK40
IN519 09- Metal OVdd Metal M40 @bee Metal .Veld Metal
- --4.-
/--
K.-' . . . . . \ ---a x
--. . __--- - . . .,----- - - \-* Y
Fig. 9 comparison of Rupture-Ductilities of Aged IN519 and HK40
50
3 4 0 - . c 0 ." 4
& 30 I: 0
A
W
20 3 4 P 3 II:
l0
0 10
- - 50 100 500 1000
Rupture Time (houre)
. -. . D IN519 0A.P. <21 D A . P . ~ OAe h e HK40 @A. P. <21 DA. P.Q1 +Am Coe 0 . 0 . + 0 0 .
0 a n 0. 0" "@0 =y. 0 . 0 - 0 0
@ 0.
- 8 .. IN519 Minimum
- * 8 * \-.zT W e + 1 8 . t * o u * -
I * 1 1 -+ + I I
Table 5. Service Conditions of IN519 Catalyst Tubes
Catalyst Tube No.
Plant 17: Tube Maker
Table 6. S4 Tube Test Items and Locations
Dimension Check
Chem. Analysis
Macrostructure --w 0 0 0
Microstructure 10 1 0 1 0
Tension Test
Creep- Rupture 1 0 1
Bottom
Location Fig. 10 Results of Tension Tests at Room Temperature on Used Catalyst Tubes
0 20 40 60 80 10E
Location
Fig. 11 Results of Tension Tests at Room Temperature on Used Catalyst Tubes
- 25 -
Location
Fig. 12 Results of Tension Tests at 871 "C on Used Catalyst Tubes
Location
Fig. 13 Results of Tension Tests at 871 "C on Used Catalyst Tubes
(1 ) Upper P o r t i o n (Loca t ion 10)
( 2 ) Lower P o r t i o n (Loca t ion 70)
Photograph 5 M ic ros t ruc tu res o f IN519 Ca ta l ys t Tube Used f o r 6 Years
x 100 x 400
( 1 ) Upper P o r t i o n (Locat ion 10)
( 2 ) Lower P o r t i o n (Locat ion 70)
Photograph 6 M ic ros t ruc tb res o f HK40 C a t a l y s t Tube Used f o r 6 Years
20.0. I 0 Cold End 1/4 from TOP O2/3 from TO
2.01 I I I I , I
10 50 100 500 1000 5000 10000
Rupture Time (hours)
Fig. 14 Results of Creep Rupture Tests on Used Catalyst Tubes
- C o l d End Looation 5 t o 30 A Loootion 30 t o 101
.27 .28 .29 .30 .31 .32 .33 .34 . 3 5
Corbon Content (2)
Fig. 15 Effect of Carbon Content on Elongation at Room Temperature of IN519
Silicon Content ( X )
Fig. 16 Effect o f Silicon Content on Elongation at Room Temperature o f IN519
30 C o l d End CI Loomtion 5 to 30 A Loootion 30 to 101
.50 .60 .70 .80 .OO 1.00
Manganeee Content (27
Fig. 17 Effect o f Manganese Content on Elongation at Room Temperature o f IN519
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