F i e l d
The present invention relates to a resin coating layer
and a life-extension method for piping that are used in a
repair of a thinned heat exchanger tube (heat transfer tube)
of a heat exchanger due to corrosion or the like and in
life-extension processing for the thinned heat exchanger
tube.
Background
A large number of heat exchanger tubes (heat transfer
tubes) are provided to a shell (body) of a heat exchanger.
A long-term operation of a heat exchanger may cause
corrosion thinning, corrosion cracks, hydrogen embrittlement
cracks, or the like in a body or a heat transfer tube of the
heat exchanger. Therefore, the heat transfer tube of the
heat exchanger is subjected to periodic inspection, in which
a thickness thereof is measured. When a portion of the heat
transfer tube where the thickness of the tube has been too
reduced, due to corrosion, to potentially cause breakage
such as holes by the next inspection, a repair is performed.
For example, a frequency of the inspection is set as
follows: (A) the periodic inspection for the entire plant is
performed every two years, and the inspection continues for
about two months; (B) a small-scale inspection is performed
one year after the periodic inspection, and the inspection
continues for about two weeks; (C) in addition, the plant
may be stopped irregularly for about two days to one week.
Generally, when there is a possibility of occurrence of
breakage of the heat transfer tube due to thinning thereof
30 by the next inspection, a repair is performed by: fusing the
portion having a risk of breakage and welding a new heat
transfer tube to that portion; repairing the portion having
a risk of kreakage while bypassing a heating medium such as
flue gas (refer, for example, Patent Literatures 1 and 2).
C i t a t i o n k i s t
P a t e n t L i t e r a t u r e
Patent Literature 1:
Publication No. 2011-2115
Patent Literature
Publication No, 2011-27288
Summary
Japanese Laid-open Patent
Japanese Laid-open Patent
T e c h n i c a l Problem
In a conventional repair work of the heat transfer tube,
the tube is cut at above and below the portion having a risk
of breakage, and a new heat transfer tube is connected to
the cut portions. In particular, as the heat exchanger is
provided with the heat transfer tubes densely arranged, when
a heat transfer tube in a depth part is thinned, a heat
transfer tube (or tubes) on a near side is also cut for
ensuring a working space. Thus, in a conventional repair
method for the heat transfer tube, it takes time and cost to
repair the heat transfer tube. This may cause, depending on
the set inspection frequency, the inspection itself can be
performed, but the repair work cannot be carried out in some
cases.
Under such a circumstance, there is demanded a repair
method that can easily and temporarily repair the heat
transfer tube thinned due to corrosion or the like.
The present invention has been made in view of the
above problems, and an object thereof is to provide a resin
coating layer and a life-extension method for piping that
allow piping to be easily repaired without involving a
cutting process of the piping.
Solution to Problem
Accoding to a first aspect of the present invention in
order to solve the above problems, there is provided aresin
coating layer formed by curing a thermo-setting resin
5 composition on an inner wall of piping for feeding
liquidlgas in a chemical plant or a power plant.
According to a second aspect of the present invention,
there is provided the resin coating layer according to the
first aspect, which is formed by sticking resin fine
particles, being obtained by charging particles of the
thermo-setting resin composition, to the inner wall of the
piping by electrostatic force while supplying the resin fine
particles into the piping and, subsequently, by heating the
piping to cure the resin fine particles.
According to a third aspect of the present invention,
there is provided the resin coating layer according to the
second aspect, wherein an average particle diameter of the
resin fine particles is not less than 30 pm and not more
than 50 ym.
According to a fourth aspect of the present invention,
there is provided the resin coating layer according to the
first aspect, which is formed by supplying the thermosetting
resin composition into the piping to fill the piping
with the thermo-setting resin composition and, subsequently,
heating the piping from outside the piping to cure the
thermo-setting resin composition on the inner wall side of
the piping while removing uncured thermo-setting resin
composition on an inner side of the piping.
According to a fifth aspect of the present invention,
there is provided the resin coating layer according to the
fourth aspect, wherein gas or air is supplied into the
piping to extract the uncured thermo-setting resin
composition inside the piping while the piping is heated.
Accoding to a sixth aspect of the present invention,
there is provided a life-extension method for piping
including: a resin fine particle sticking step of sticking,
by electrostatic force, resin fine particles, which are
5 obtained by charging particles of a thermo-setting resin
composition, to an inner wall of piping for feeding
liquid/gas in a chemical plant or a power plant while
supplying the resin fine particles into the piping; and a
resin coating layer forming step of forming a resin coating
layer by heating the piping to cure the resin fine particles
stuck to the inner wall of the piping.
Accoding to a seventh aspect of the present invention,
there is provided the life-extension method for piping
according to the sixth aspect, wherein an average particle
15 diameter of the resin fine particles is not more than 30 pm
and not less than 50 pm.
Accoding to an eighth aspect of the present invention,
there is provided the life-extension method for piping
inclduing: a thermo-setting resin composition filling step
of supplying a thermo-setting resin composition into piping
for feeding liquid/gas in a chemical plant or a power plant
to fill the piping with the thermo-setting resin
composition; and a resin coating layer forming step of
heating the piping to cure the thermo-setting resin
composition on an inner wall side of the piping while
removing uncured thermo-setting resin composition on an
inner side of the piping to form a resin coating layer on an
inner wall 3f the piping.
Accoding to a ninth aspect of the present invention,
there is provided the life-extension method for piping
according to claim 8, wherein gas or air is supplied into
the piping to extract the uncured thermo-setting resin
composition inside the piping while the piping is heated.
Advantageous Effects of Invention
According to the present invention, the resin coating
layer is formed on the inner wall of the heat transfer tube
having a defective part, so that it is possible to easily
repair the heat transfer tube without involving a cutting
process of the heat transfer tube,
Brief Description sf Drawings
FIG. 1 is a schematic view illustrating a resin coating
layer according to a first embodiment of the present
invention.
FIG. 2 is a flowchart illustrating an example of a life
extension method for piping according to the first
embodiment of the present invention.
FIG. 3 is an explanatory view illustrating a forming
process of the resin coating layer.
FIG. 4 is a view illustrating a part of a heat
exchanger.
FIG. 5 is a flowchart illustrating an example of a life
extension method for piping according to a second embodiment
of the present invention.
FIG. 6 is an explanatory view illustrating a forming
process of the resin coating layer.
FIG. 7 is an explanatory view illustrating a
25 configuration for supplying air into the heat transfer tube.
FIG. 8 is an explanatory view illustrating a state
where air is introduced into the heat transfer tube.
FIG. 9 is a view illustrating an example of a method of
removing an uncured thermo-setting resin composition.
FIG. 10 is a view illustrating an example of a method
of removing an uncured thermo-setting resin composition.
Description of Embodiments
Hereinafter, the present invention will be described
with reference to the drawings. It should be noted that the
present invention is not limited to the following
embodiments. In addition, constituting elements in the
following embodiments include elements which may be easily
assumed by those skilled in the art, which are substantially
the same, and which are so-called in an equivalent range.
Moreover, constituent elements disclosed in the following
embodiments may be appropriately combined.
First Embodiment
A resin coating layer according to a first embodiment
of the present invention will be described with reference to
the drawings. In the present embodiment, as a piping for
feeding liquid/fluid in a chemical plant or a power plant, a
heat transfer tube provided in a heat exchanger is used.
FIG. 1 is a schematic view illustrating the resin coating
layer according to the first embodiment of the present
invention. As illustrated in FIG. 1, a resin coating layer
10A according to the present embodiment is formed on an
inner wall ila of a heat transfer tube (piping) 11.
The resin coating layer 10A according to the embodiment
is formed by curing fine particles of a thermo-setting resin
25 composition whose curing reaction is started at a low
temperature. As the thermo-setting resin composition, a
resin composition mainly containing, for example, a phenol
resin, a urea resin, a melamine resin, an epoxy resin, a
polyurethane resin, or the like can be used. In the present
30 embodiment, it is preferable to use a thermo-setting resin
composition mainly containing an epoxy resin because of the
following reasons: it can contact a heating medium inside
the heat transfer tube 11: it can stably withstand
temperature changes of the heat transfer tube 11; it is easy
to use and handle; and it is advantageous in cost reduction.
The thermo-setting resin composition used for forming the
resin coating layer 10A according to the present embodiment
may be used singly or in combination of two or more. The low
temperatures stated herein refer to those in a temperature
range of not less than 70°C and not more than 180°,
preferably not less than 120°C and not more than 160°, more
preferably not less than 140°C and not more than 155°, and
still more preferably about 150'.
Further, the thermo-setting resin composition
preferably contains metal particles such as aluminum
pigments. The thermo-setting resin composition containing
the metal particles can suppress reduction in thermal
conductivity of the heat transfer tube 11 when the heating
medium is fed into the heat transfer tube 11.
A film thickness of the resin coating layer 10A
according to the embodiment is preferably in a range of not
0.1 mm and not more than 15 mm in terms of a size of an
inner diameter of the heat transfer tube 11 and performance
in suppressing deterioration due to the heating medium
flowing in the heat transfer tube 11, more preferably not
less than 5.5 mm and not more than 10 mm, and still more
preferably not less than 1 mm and not more than 5 mm.
Forming the resin coating layer 10A according to the
embodiment on the inner wall 1la of the heat transfer tube
11 allows the heat transfer tube 11 thinned due to corrosion
or the like to be easily repaired without involving a
cutting process of the heat transfer tube 11.
30 An example of a life extension method for piping
according to the present embodiment that forms the thus
configured resin coating layer 10A will be described using
the drawings. FIG. 2 is a flowchart illustrating an example
of the life extension method for piping according to the
present embodiment, and FIG. 3 is an explanatory view
illustrating a forming process of the resin coating layer.
As illustrated in FIG. 2, the life extension method for
piping according to the present embodiment includes the
following processes:
(a) resin fine particle sticking process (step S11) in
which resin fine particles 21 obtained by charging particles
of the thermo-setting resin composition are supplied into
the heat transfer tube (piping) 11, and the resin fine
particles 21 are stuck to the inner wall lla of the heat
transfer tube 11 by electrostatic force; and
(b) resin coating layer forming process (step ,512) in
which the heat transfer tube 11 is heated to cure the resin
fine particles 21 stuck to the inner wall 1la of the heat
transfer tube 11 to thereby form the resin coating layer 10A.
As illustrated in FIG. 4, a resin fine particle supply
means 24 for supplying the resin fine particles 21 into the
heat transfer tube 11 is provided outside a heat exchanger
20 23. The resin fine particles 21 are supplied from the resin
fine particle supply means 24 into the heat transfer tube 11
of the heat exchanger 23. Then, as illustrated in FIG. 3,
the resin fine particles 21 supplied into the heat transfer
tube 11 are stuck to the inner wall lla of the heat transfer
25 tube 11 by electrostatic force (step S11).
As described above, the resin fine particles 21 are
particles obtained by charging particles of the thermosetting
resin composition. As a material for forming the
resin fine particles 21, the above-mentioned thermo-setting
30 resin composition whose curing reaction is started at a low
temperature is used. As the thermo-setting resin composition,
a resin composition mainly containing, for example, a phenol
resin, a urea resin, a melamine resin, an epoxy resin, a
polyurethane resin, or the like can be used. In the present
embodiment, it is preferable to use a thermo-setting resin
composition mainly containing an epoxy resin because of the
following reasons: it can contact a heating medium inside
the heat transfer tube 11; it can stably withstand
temperature changes of the heat transfer tube 11; it is easy
to use and handle; and it is advantageous in cost reduction,
The thermo-setting resin composition used for forming the
resin coating layer 10A according to the present embodiment
may be used singly or in combination of two or more.
Further, as described above, the thermo-setting resin
composition preferably contains metal particles such as
aluminum pigments. The thermo-setting resin composition
containing the metal particles can suppress reduction in
thermal conductivity of the heat transfer tube 11 when the
heating medium is fed into the heat transfer tube 11.
An average particle diameter of the resin fine
particles 21 is preferably in a range of not less than 10 pm
and not more than 150 pm so that the resin fine particles 21
are stably supplied into the heat transfer tube 11 and
stably stuck to the entire surface of the inner wall lla of
the heat transfer tube 11, more preferably not less than 30
pm and not more than 50 pm, and still more preferably, not
less than 35 pm and not more than 45 pm.
The charged resin fine particles 21 are stored in the
resin fine particle supply means 24. As a method of charging
the fine particles of the thermo-setting resin composition,
a conventionally-known electrostatic method can be used.
Specifically, examples of the electrostatic methods include
a method in which a high voltage (e.g., -40 KV to -90 KV)
obtained by a high-voltage electrostatic generator is
applied to the fine particles of the thermo-setting resin
composition to charge the same.
The r e s i n f i n e p a r t i c l e s 21 s u p p l i e d i n t o t h e heat
t r a n s f e r tube 11 a r e s t u c k t o t h e i n n e r wall 11a of t h e heat
t r a n s f e r tube 11 by e l e c t r o s t a t i c f o r c e .
In t h e p r e s e n t embodiment, t h e r e s i n f i n e p a r t i c l e s 21
a r e p r e v i o u s l y charged so a s t o be s t u c k t o t h e i n n e r wall
11a of t h e heat t r a n s f e r tube 11 by e l e c t r o s t a t i c f o r c e .
A l t e r n a t i v e l y , however, an e l e c t r o s t a t i c device may be used
t o s t i c k t h e r e s i n f i n e p a r t i c l e s 21 t o t h e i n n e r wall 11a
of t h e heat t r a n s f e r tube 11. The use of t h e e l e c t r o s t a t i c
d e v i c e a l l o w s t h e r e s i n f i n e p a r t i c l e s 21 t o be s t u c k t o t h e
i n n e r wall 11a of t h e heat t r a n s f e r tube 11 more s t a b l y .
A f t e r s t i c k i n g of t h e r e s i n f i n e p a r t i c l e s 21 t o t h e
i n n e r wall l l a of t h e heat t r a n s f e r tube 11, t h e heat
t r a n s f e r tube 11 is heated t o cure t h e r e s i n f i n e p a r t i c l e s
21 s t u c k t o t h e i n n e r wall 1 l a of t h e heat t r a n s f e r tube 11
t o thereby form t h e r e s i n c o a t i n g l a y e r 1OA ( s t e p S12).
Heating t h e heat t r a n s f e r tube 11 from o u t s i d e i n c r e a s e s a
temperature of t h e i n n e r wall 1 l a of t h e heat t r a n s f e r tube
11, t h e r e b y c u r i n g t h e r e s i n f i n e p a r t i c l e s 21 s t u c k t o the
20 i n n e r wall l l a of t h e heat t r a n s f e r tube 11.
Examples of a h e a t i n g method f o r t h e heat t r a n s f e r tube
11 i n c l u d e s : h e a t i n g an o u t e r p e r i p h e r a l s u r f a c e of t h e heat
t r a n s f e r tube 11 u s i n g a h e a t i n g e l e c t r i c wire a t t a c h e d t o
t h e o u t e r p e r i p h e r a l s u r f a c e of t h e heat t r a n s f e r tube 11;
25 h e a t i n g t h e o u t e r p e r i p h e r a l s u r f a c e of t h e heat t r a n s f e r
tube 11 u s i n g a h e a t e r ; and h e a t i n g t h e heat t r a n s f e r tube
11 using high-temperature gas ( f l u e gas) flowing i n a s h e l l
(body) of t h e heat exchanger 23.
By c u r i n g t h e r e s i n f i n e p a r t i c l e s 21 s t u c k t o t h e
30 i n n e r wall 11a of t h e heat t r a n s f e r tube 11, a d j a c e n t r e s i n
f i n e p a r t i c l e s 21 a r e bonded t o each o t h e r t o thereby form
t h e r e s i n c o a t i n g l a y e r 10A according t o t h e p r e s e n t
embodiment on t h e i n n e r wall 11a of t h e heat t r a n s f e r tube
Further, in the present embodiment, the number of times
that the rssin fine particle supply means 24 supplies the
resin fine particles 21 into the heat transfer tube 11 is
set to one, but the number is not limited thereto. The resin
fine particle supply means 24 may supply the resin fine
particles 21 into the heat transfer tube 11 plurality of
times depending on a size of the inner diameter of the heat
transfer tube 11, a sticking condition of the resin fine
particles 21 to the inner wall 1Pa of the heat transfer tube
11, and the like.
Thus, by using the life-extension method for piping
according to the present embodiment, the resin coating layer
10A according to the present embodiment can be formed on the
inner wall lla of the heat transfer tube 11. Even if a
defect, such as cracks or holes, occurs in the heat transfer
tube 11 resulting from progress of corrosion at a portion of
the heat transfer tube 11 where thinning or the like occurs,
forming the resin coating layer 10A according to the present
embodiment on the inner wall Ila of the heat transfer tube
11 allows the heat transfer tube 11 to be temporarily and
easily repaired without involving a cutting process of the
heat transfer tube 11. As a result, it is possible to
prevent the heating medium flowing in the heat transfer tube
11 from leaking outside. Further, the resin fine particles
21 contain the metal particles, so that even when the resin
coating layer 10A according to the present embodiment is
formed in the heat transfer tube 11, it is possible to
suppress reduction in thermal conductivity of the heat
transfer tube 11 when the heating medium is fed into the
heat transfer tube 11, which in turn can suppress reduction
in performance of the heat exchanger 23.
Second Embodiment
A resin coating layer according to a second embodiment
of the present invention will be described with reference to
the drawings. Like the resin coating layer 10A according to
the first embodiment illustrated in FIG. 1, a resin coating
layer 10B according to the present embodiment is formed on
an inner wall lla of a heat transfer tube 11.
The resin coating layer 10B according to the present
embodiment is formed. by curing a thermo-setting resin
composition whose curing reaction is started at a low
temperature. As the thermo-setting resin composition, a
resin composition mainly containing, for example, a phenol
resin, a urea resin, a melamine resin, an epoxy resin, a
polyurethane resin, or the like can be used. In the present
15 embodiment, it is preferable to use a resin composition
mainly containing an epoxy resin because of the following
reasons: it can contact a heating medium inside the heat
transfer tube 11; it can stably withstand temperature
changes of the heat transfer tube 11; it is easy to use and
20 handle; and it is advantageous in cost reduction. The
thermo-setting resin composition used for forming the resin
coating layer 10B according to the present embodiment may be
used singly or in combination of two or more. The low
temperatures stated herein refer to those in a temperature
25 range of not less than 40°C and not more than 60'.
Forming the resin coating layer 10B according to the
embodiment on the inner wall lla of the heat transfer tube
11 allows the heat transfer tube 11 thinned due to corrosion
or the like to be easily repaired without involving a
30 cutting process of the heat transfer tube 11.
Further, the thermo-setting resin composition
preferably contains metal particles such as aluminum
pigments. The thermo-setting resin composition containing
the metal particles can suppress reduction in thermal
conductivity of the heat transfer tube 11 when the heating
medium is fed into the heat transfer tube lle
An example of a life extension method for piping
according to the present embodiment that forms the thus
configured resin coating layer 10B will be described using
the drawings. FIG. 5 is a flowchart illustrating an example
of the life extension method for piping according to the
present embodiment, and FIG. 6 is an explanatory view
/
illustrating a forming process of the resin coating layer.
As illustrated in FIG. 5, the life extension method for
piping according to the present embodiment includes the
following processes:
(a) thermo-setting resin composition filling process
(step S21) in which a thermo-setting resin composition 31 is
supplied into the heat transfer tube 11 to fill the heat
transfer tube 11 therewith; and
(b) resin coating layer forming process (step S22) in
which the heat transfer tube 11 is heated to cure the
20 thermo-setting resin composition 31 on the inner wall 1la
side of the heat transfer tube 11 while an uncured thermosetting
resin composition 31 on an inner side of the heat
transfer tube 11 is removed to thereby form the resin
coating layer 10B on the inner wall lla of the heat transfer
25 tube 11.
As illustrated in FIG. 6, the thermo-setting resin
composition 31 is supplied into the heat transfer tube 11 of
a heat exchanger 23 to fill the heat transfer tube 11
therewith (step S21) .
As illustrated in FIG. 7, a thermo-setting resin
3
composition supply means 32 for supplying the thermo-setting
resin composition 31 into the heat transfer tube 11 4s
provided outside the heat exchanger 23. The thermo-setting
resin composition 31 is supplied from the thermo-setting
resin composition supply means 32 into the heat transfer
tube 11 of the heat exchanger 23.
As described above, as a material for forming the
thermo-setting resin composition 31, the thermo-setting
resin composition whose curing reaction is started at a low
temperature is used. As the thermo-setting resin composition,
a resin composition mainly including, for example, a phenol
resin, a urea resin, a melamine resin, an epoxy resin, a
polyurethane resin, or the like can be used. In the present
embodiment, it is preferable to use a resin composition
mainly including an epoxy resin because of the following
reasons: it can contact a heating medium inside the heat
transfer tube 11; it can stably withstand temperature
changes of the heat transfer tube 11; it is easy to use and
handle; and it is advantageous in cost reduction. The
thermo-setting resin composition used for forming the resin
coating layer 10B according to the present embodiment may be
used singly or in combination of two or more.
Further, as described above, the thermo-setting resin
composition 31 preferably contains the metal particles such
as aluminum pigments. The thermo-setting resin composition
containing the metal particles can suppress reduction in
thermal conductivity of the heat transfer tube 11 when the
heating medium is fed into the heat transfer tube 11.
When the thermo-setting resin composition 31 is
supplied into the heat transfer tube 11, a solution
containing the thermo-setting resin composition 31 may be
supplied considering a viscosity of the thermo-setting resin
30 composition 31,
After the heat transfer tube .I1 is filled with the
thermo-setting resin composition 31, the heat transfer tube
11 is heated from outside to cure the thermo-setting resin
composition 31 on the inner wall lla side of the heat
transfer tube 11 while the uncured thermo-setting resin
composition 31 on the inner side of the heat transfer tube
11 is removed (step S22),
As described in the previous embodiment, examples of a
heating method for the heat transfer tube 11 includes:
heating an outer peripheral surface of the heat transfer
tube 11 using a heating electric wire attached to the outer
peripheral surface of the heat transfer tube 11; heating the
outer peripheral surface of the heat transfer tube 11 using
a heater; and heating the heat transfer tube 11 using hightemperature
gas (flue gas) flowing in a shell (body) of the
heat e~chang~e2r3 .
Further, when the heat transfer tube 11 is heated from
15 outside, a heating temperature, a heating time, and the like
are controlled considering the diameter size of the heat
transfer tube 11 and the like. This causes a temperature
difference in the thermo-setting resin composition 31 inside
the heat transfer tube 11, thereby allowing a difference in
20 progress of the curing reaction of the thermo-setting resin
composition 31 in the heat transfer tube 11 to be made. As a
result, it is possible to adjust a thickness of the thermosetting
resin composition 31 to be cured in the heat
transfer tube 11.
Further, as illustrated in FIG. 7, an air supply means
33 is provided outside the heat exchanger 23. The air supply
means 33 introduces air 34 into the heat transfer tube 11 to
extract the uncured thermo-setting resin composition 31 on
the inner side of the heat transfer tube 11. The heat
30 transfer tube 11 is heated from outside, so that the heat is
transferred from the inner wall 1la side of the heat
transfer tube 11. Accordingly, the temperature is higher at
the inner wall 11a side of the heat transfer tube 11 than at
a center portion thereof, Thus, the thermo-setting resin
composition 31 in the vicinity of the inner wall lla of the
heat transfer tube 11 is cured faster than the thermosetting
resin composition 31 existing around the center of
the heat transfer tube, Further, the uncured thermo-setting
resin composition 31 is in a high viscosity state, while the
cured thermo-setting resin composition 31 is low in
viscosity and stuck to the inner wall 1la of the heat
transfer ti- be 11. Thus, as illustrated in FIG. 8, by
introducing the air 34 into the heat transfer tube 11, it is
possible to remove only the uncured thermo-setting resin
composition 31 on the inner side of the heat transfer tube
11 while curing the thermo-setting resin composition 31 on
the inner wall lla side of the heat transfer tube 11.
As a result, a hollow resin film can be formed in the
heat transfer tube 11, whereby the resin coating layer 10B
according to ,the present embodiment is formed only at the
inner wall lla side of the heat transfer tube 11,
Further, in the present embodiment, the air 34 is
introduced from the air supply means 33 provided outside the
heat exchanger 23 into the heat transfer tube 11, but what
is introduced is not limited thereto. An inert gas such as
nitrogen (N2) gas or argon (Ar) gas may be introduced.
Further, in the present embodiment, the air supply
25 means 33 is used as a means for removing only the uncured
thermo-setting resin composition 31 on the inner side of the
heat transfer tube 11, but the means is not limited thereto.
FIGS. 9 and 10 are views each illustrating an example of a
method of removing the uncured thermo-setting resin
30 composition. As illustrated in FIG. 9, a spherical body 35
is introduced to supply the air 34 into the heat transfer
tube 11, thereby allowing removal of only the uncured
thermo-setting resin composition 31 on the inner side of the
heat transfer tube 11 while curing the uncured thermosetting
resin composition 31 in the heat transfer tube 11.
Further, as illustrated in FIG. 10, by fitting a
pushing mer.Ser 37 having a diameter smaller than the inner
diameter of the heat transfer tube 11 to a leading end of a
cable 36 and introducing the pushing member 37 into the heat
transfer tube 11, only the uncured thermo-setting resin
composition 31 on the inner side of the heat transfer tube
11 can be removed.
Further, in the present embodiment, the number of times
that the thermo-setting resin composition supply means 32
supplies the thermo-setting resin composition 31 into the
heat transfer tube 11 is set to one, but the number is not
limited thereto. The thermo-setting resin composition supply
means 32 may supply the thermo-setting resin composition 31
into the heat transfer tube 11 plurality of times depending
on the size of the inner diameter of the heat transfer tube
11, a film thickness of the resin coating layer 10B formed
on the inner wall 1la of the heat transfer tube 11, and the
like,
Further, in the present embodiment, the number of times
that the air supply means 33 supplies the air 34 into the
heat transfer tube 11 is set to one, but the number is not
limited thereto. The air supply means 33 may supply the air
34 into the heat transfer tube 11 plurality of times
depending on the size of the inner diameter of the heat
transfer tube 11 and the like, a film thickness of the resin
coating layer 10B formed by the thermo-setting resin
composition 31 supplied into the heat transfer tube 11 at
30 the first time, and the like.
Thus, by using the life-extension method for piping
according to the present embodiment in which the difference
in the temperature transferred to inside of the heat
transfer tube I1 when the heat transfer tube 11 is heated
from outside is utilized, only the uncured thermo-setting
resin composition 31 can be removed from the heat transfer
tube 11. Accordingly, the resin coating layer 10B according
to the present embodiment can be formed only on the inner
wall lla side of the heat transfer tube 11. Thus, even if a
defect such as cracks or holes occurs in the heat transfer
tube 11 resulting from progress of corrosion at a portion of
the heat transfer tube 11 where thinning or the like occurs,
forming the resin coating layer 10B according to the present
embodiment on the inner wall 11a of the heat transfer tube
11 allows the heat transfer tube 11 to be temporarily and
easily repaired without involving a cutting process of the
heat transfer tube 11. As a result, it is possible to
prevent the heating medium flowing in the heat transfer tube
11 from leaking outside. Further, the resin coating layer
10B according to the present embodiment is cured by being
heated from outside the heat transfer tube 11, so that a
one-liquid type thermo-setting resin composition can be used
20 to form the resin coating layer 10B. Thus, as compared to a
case where a two-liquid type thermo-setting resin
composition is used to form the resin coating layer 10B, a
cured state, such as a film thickness, of the thermo-setting
resin composition 31 can be easily adjusted. Further, the
25 thermo-setting resin composition 31 contains the metal
particles, so that even when the resin coating layer 10B
according to the present embodiment is formed in the heat
transfer tube 11, it is possible to suppress reduction in
thermal conductivity of the heat transfer tube 11 when the
30 heating medium is fed into the heat transfer tube 11, which
in turn can suppress reduction in performance of the heat
exchanger 23,
Although the present invention is applied to the heat
transfer tube 11 provided in a fin-tube heat exchanger in
the above embodiments, but the application is not limited
thereto. The invention may be applied to heat exchangers of
other types, such as a gas-to-liquid air-cooled heat
exchanger and a direct contact heat exchanger. Further, the
application of the resin coating layer 10A according to the
present embodiment is not limited to a gas-to-liquid heat
exchanger, but the resin coating layer 1024 may be useful in
a liquid-to-liquid heat exchanger or a gas-to-gas heat
exchanger. Examples of the liquid-to-liquid heat exchanger
include a spiral heat exchanger, a plate heat exchanger, a
double-pipe heat exchanger, a shell-and-tube heat exchanger
(multi-pipe cylindrical heat exchanger), a spiral tube heat
exchanger, a spiral plate heat exchanger, a tank coil heat
exchanger, a tank ~acket heat exchanger, and a direct
contact liquid-to-liquid heat exchanger. Examples of the
gas-to-gas heat exchanger include a stationary heat
exchanger, a regenerative rotary heat exchanger, a periodic
flow regenerative heat exchanger, and a vortex tube.
Further, in the embodiments, the present invention is
applied to the heat transfer tube provided in the heat
exchanger, but the application is not limited thereto. For
example, piping to be used in the present invention is not
limited in particular as long as it can feed liquid/gas in a
chemical plant, a power plant, or the like. Thus, for
example, the present invention can also be applied to a
repairing work of piping for corrosive liquid, piping for
corrosive gas, piping for high-temperature water, piping for
low-temperature water, or the like.

Claims
1. A resin coating layer formed by curing a thermo-setting
resin composition on an inner wall of piping for
feeding liquid/gas in a chemical plant or a power plante
The resin coating layer according to claim 1, which is
formed by sticking resin fine particles, being obtained
by charging particles of the thermo-setting resin
composition, to the inner wall of the piping by
electrostatic force while supplying the resin fine
particles into the piping and, subsequently, by heating
the piping to cure the resin fine particles.
The resin coating layer according to claim 2, wherein
an average particle diameter of the resin fine
particles is not less than 30 pm and not more than 50
Pme
The resin coating layer according to claim 1, which is
formed by supplying the thermo-setting resin
composition into the piping to fill the piping with the
thermo-setting resin composition and, subsequently,
heating the piping from outside the piping to cure the
thermo-setting resin composition on the inner wall side
of the piping while removing uncured thermo-setting
resin composition on an inner side of the piping.
The resin coating layer according to claim 4, wherein
gas or air is supplied into the piping to extract the
uncured thermo-setting resin composition inside the
piping while the piping is heated.
6. A life-extension method for piping comprising:
a resin fine particle sticking step of sticking,
by electrostatic force, resin fine particles, which are
obtained by charging particles of a thermo-setting
resin composition, to an inner wall of piping for
feeding liquid/gas in a chemical plant or a power plant
while supplying the resin fine particles into the
piping; and
a resin coating layer forming step of forming a
resin coating layer by heating the piping to cure the
resin fine particles stuck to the inner wall of the
piping.
The life-extension method for piping according to claim
6, wherein an average particle diameter of the resin
fine particles is not more than 30 pm and not less than
50 pm.
A life-extension method for piping comprising:
a thermo-setting resin composition filling step of
supplying a thermo-setting resin composition into
piping for feeding liquid/gas in a chemical plant or a
power plant to fill the piping with the thermo-setting
resin composition; and
a resin coating layer forming step of heating the
piping to cure the thermo-setting resin composition on
an inner wall side of the piping while removing uncured
thermo-setting resin composition on an inner side of
the piping to form a resin coating layer on an inner
wall of the piping.
The life-extension method for piping according to claim
8, wherein gas or air is supplied into the piping to
extract the uncured thermo-setting resin composition
inside the piping while the piping is heated.