NZ616596B2 - Tube monitor and process measurement and control in or for a reformer - Google Patents
Tube monitor and process measurement and control in or for a reformer Download PDFInfo
- Publication number
- NZ616596B2 NZ616596B2 NZ616596A NZ61659613A NZ616596B2 NZ 616596 B2 NZ616596 B2 NZ 616596B2 NZ 616596 A NZ616596 A NZ 616596A NZ 61659613 A NZ61659613 A NZ 61659613A NZ 616596 B2 NZ616596 B2 NZ 616596B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- tube
- reformer
- tubes
- temperature
- length
- Prior art date
Links
- 238000005259 measurement Methods 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title description 22
- 238000006073 displacement reaction Methods 0.000 claims description 7
- 238000009966 trimming Methods 0.000 description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- 239000002737 fuel gas Substances 0.000 description 7
- 150000002500 ions Chemical class 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910000480 nickel oxide Inorganic materials 0.000 description 4
- 229940035295 Ting Drugs 0.000 description 3
- 238000009529 body temperature measurement Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000006057 reforming reaction Methods 0.000 description 3
- 238000001991 steam methane reforming Methods 0.000 description 3
- 230000001960 triggered Effects 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N carbon monoxide Chemical class [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000875 corresponding Effects 0.000 description 2
- 230000001186 cumulative Effects 0.000 description 2
- 230000001419 dependent Effects 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 239000008239 natural water Substances 0.000 description 2
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 2
- 238000002407 reforming Methods 0.000 description 2
- 230000000246 remedial Effects 0.000 description 2
- 238000000629 steam reforming Methods 0.000 description 2
- NLZUEZXRPGMBCV-UHFFFAOYSA-N Butylhydroxytoluene Chemical compound CC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 NLZUEZXRPGMBCV-UHFFFAOYSA-N 0.000 description 1
- 229920002456 HOTAIR Polymers 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000000737 periodic Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000001105 regulatory Effects 0.000 description 1
Abstract
616596 A method of real time monitoring of the temperature of reformer tubes in a reformer reactor is disclosed. The method in essence comprises measuring the length of each tube and using that measurement to calculate the temperature of the tube. This information can be used to provide a real time indication of the temperature distribution and overheat monitoring/protection of a reformer in real time and allow for estimation of tube life. indication of the temperature distribution and overheat monitoring/protection of a reformer in real time and allow for estimation of tube life.
Description
TE SPECIFICATION
TUBE MONITOR AND PROCESS MEASUREMENT AND CONTROL IN OR FOR A
REFORMER
THE FIELD OF THE INVENTION
The present invention relates to a tube monitor in or for a reformer such as,
but not limited to a steam reformer that may be used in the tion of methanol
More particularly present invention relates to a tube monitor for overheat
monitoring and/or protection and/or tube life prediction in or for a reformer such
as, but not d to a steam reformer that may be used in the production of
methanol.
BACKGROUND TO THE INVENTION
The production process of methanol utilises a reformer stage. In the reformer
stage, a natural gas and water mixture moves through heated tubes. Each tube
contains nickel oxide (NiO) catalyst. This allows an endothermic reforming reaction
to occur.
This process is also known as steam reforming (SR), mes referred to as
steam methane reforming (SMR).
An external source of hot gas is used to heat tubes (reformer tubes) in which
the catalytic reaction takes place. This reaction converts steam and lighter
hydrocarbons such as methane into en and carbon oxides (syngas). The
l product of this process includes a mixture of H2 + C0 + CO;_ (+ H20).
Reformer tubes are hollow tubes usually vertically ded in a plurality of
rows within a reactor (furnace enclosure). The furnace may be 15m tall and 25m
square for e, housing some 700 tubes each around 12—14m tall. The
reformer tubes in a furnace are typically suspended by s (or counterweights)
off hangers that are located above the tubes.
Process ion temperatures see the tubes subjected to temperatures in
the range of 900 and 950 degrees Celsius. The approximate optimum temperature
for process efficiency is 930°C. A ature lower than this will result in
significant methane not being converted ne slip) which may affect the
efficiency of the plant operation. Conversely, temperatures higher than 930°C will
result in increased creep and reduced tube lifespan. Going from 930° to 950°, the
tube life span is reduced by about half.
The lifespan of a tube is determined by their slow expansion at high
temperatures (creep). Tubes creep both axially and diametrically. It is diametric
creep that has the predominant impact on an of the tubes. Operating the
reformer too hot will shorten the life of the tubes and premature and unexpected
failures can hence be costly. A leak in one tube can cause damage to the
surrounding tubes. Currently each tube can cost around US$20,000. Further,
replacing failed tubes requires a full plant shut down, potentially costing millions of
dollars of lost production.
A common method for ting SMR overheats is to measure energy in and
energy out of the furnace to ensure excessive tube temperatures are not possible.
lly, overall temperature control in the furnace is achieved by regulating fuel
gas re over all of the burners. Individual tube temperatures are controlled by
fuel gas flow valves at each burner (via trimming). Accordingly, the trimming one
burner may reduce the temperature in adjacent tubes, but that may then result in a
peak of temperature elsewhere in the furnace.
This global approach does not always protect individual or small groups of
tubes that can be overheated through operator error or equipment ction.
This method of overheat protection is hence not fully effective, and burnouts of the
reformer can, and do, mes occur. There are us reported failures
using this method.
Measurement of the temperature of individual tubes is typically achieved by
sight ports h the furnace wall. The sight ports are opened or able to be
opened to allow infra red instrument access to determine and measure the
temperature of tubes. However, opening the sight ports (without a glass )
allows cold air into the furnace and/or hot air out, and can cause a temperature
change in tubes near the sight ports. Further, the accuracy of such measurements
is low and the instruments may be reading a temperature variation of up to .
Further still, such a manual approach to temperature measurement is very time—
consuming (for example it may take between 40 minutes to an hour for an operator
to make their way around the reformer measuring temperatures). As a result, the
frequency of measurement is very low and may only occur at a few times in a 24
hour period.
In addition the sight ports do not allow for visibility of all tubes to be ed
because some tubes are ed by the thickness of the furnace refractory lining.
Therefore some tubes (particularly those around the perimeter) may not get
monitored, as accurately, or at all. It has also been found that this type of
ature measurement is potentially quite variable between different operators,
further affecting the accuracy and reliability of temperature data.
When adverse tube temperatures are detected by the infrared instrument, the
tube temperature needs to be ed. Temperature control of the whole furnace
is achieved by fuel gas pressure over all of the burners. Temperature of individual
tubes can be controlled (trimmed) by dedicated gas flow valves to appropriate
adjacent burners. A person who has observed, using the infra red ment, one
tube being of a high temperature may for example turn down the dedicated valve
at an adjacent burner to reduce a tube's temperature. This process may be
iterative and ongoing across all tubes in the furnace. This may in part be because
adjusting a change in temperature of one tube may have an e effect on the
temperature of another tube in the furnace.
The operations management preferably control the burners in an effort to
maintain a relatively even temperature throughout the entire reformer by trimming.
A well trimmed reformer will generally result in the t efficiency of the
reforming process.
Creep affects the life span of a tube. A typical lifespan of a tube is
approximately 11 years. Creep is currently measured each time a plant is shut
down. This may be roughly every 4 years. When the plant has been shut down, a
device such as that shown in U52005/0237519 can measure the inside diameter of
each tube along its length. This data can be ed to the tube when new.
Where the degree of measured creep has exceeded a certain predetermined limit, a
decision can be made to discard the tube and replace it with a new tube because of
the statistical dge that the old tube is likely to fail in the next four year cycle.
However these data only become available when the plant is shut down at
which point it is too late to order new tubes if there are insufficient spare tubes.
The temperature data derived from individual tube growth measurements can be
used to calculate the tube life consumed and hence allow sufficient tubes to be held
for a planned plant shut down.
SUMMARY OF THE INVENTION
It may therefore be an object of the present invention to provide an improved
method of real time monitoring temperature of a reformer tube.
It may also be an object of the t invention to e a monitor to
provide a real time indication of the temperature distribution of a reformer.
It may therefore be an object of the present invention to provide at
monitoring/protection in real time of the temperature of a reformer tube or tubes
within a reformer furnace.
It may also be an object of the present ion to provide a tube growth
monitor and/or s measurement and/or control in or for a reformer and/or to
provide the public with a useful choice.
According to a first aspect the invention y consists in our method of
ring the temperature of a reformer tube in a reformer reactor comprising:
measuring the length of said tube,
calculating said temperature using said measured length.
According to a further aspect measuring said length of said tube comprises
measuring the displacement of a hanger supporting said tube.
According to a further aspect said hanger supports a plurality of tubes.
According to a further aspect said measuring of length occurs over time, and
a change in length over time is calculated.
According to a further aspect said said measuring of length occurs over time, and
a change in temperature over time is calculated from said change in length
over said time.
According to a further aspect the invention y comprises a method of
monitoring temperature distribution in a reformer reactor that es a plurality of
distributed tubes, comprising:
using the method of any one or more of the previous clauses, to measure at
least some of said tubes.
According to a further aspect the majority of said tubes in said er are
monitored.
According to a further aspect said ing the length of said tube is done
autonomously by a displacement transducer.
According to a further aspect said displacement transducer transmits measurement
data wirelessly to a receiver.
According to a further aspect said measured length and/or said ated
temperature is displayed in a manner reflecting the location of the tubes in the
reactor.
According to a further aspect said display is a thermal contour map.
According to a further aspect said display is displayed on a mobile device.
ing to a further aspect said display is used to trim one or more burners in
said reformer reactor.
According to a further aspect said length measurements and said calculated
atures are stored.
According to a further aspect said measured length and/or said calculated
temperature is used to trim one or more burners in said reformer reactor.
According to a further aspect said method triggers a first alarm if said measured
length or said calculated temperature exceeds a first predetermined threshold.
According to a further aspect said method rs a second alarm if:
said measured length or said calculated temperature of a predetermined
number of tubes, exceeds a second predetermined old.
According to a further aspect in response to said alarm, one or more burners in said
reactor are trimmed.
According to a further aspect in response to said second alarm a fuel gas flow into
said er reactor is reduced.
According to a further aspect said first predetermined threshold is adjusted over
time to compensate for expected creep in said tube.
According to a further aspect said second predetermined threshold is adjusted over
time to compensate for expected creep in said tube.
According to a r aspect said method further comprises periodically calculating
an indication of tube life consumed during said period using said measured length
or said calculated ature data.
According to a further aspect said method calculates a tive life consumed
from said periodic calculation of tube life consumed.
According to a further aspect said method predicts a failure time based on said
cumulative life consumed.
According to a further aspect said predicted failure time is used to plan a scheduled
shutdown of said reformer reactor.
According to a further aspect said predicted failure time is used to plan replacement
of said tube prior to a reformer shut down.
According to a further aspect said measured length data and/or said calculated
temperature data is received by a controller, and
said controller autonomously causes ng of a burner fuel gas supply
valve according to a predetermined algorithm.
According to a further aspect said measured length data and/or said calculated
temperature data is received by a ller, and
said controller autonomously causes a change in a fuel gas flow into said
reactor according to a predetermined algorithm.
According to a further aspect said change in fuel gas flow into said reactor is a
reduction.
According to a further aspect the ion consists in a reactor employing the
method of any one of the preceding claims.
According to a further aspect the invention consists in a method ntially as
herein described and with reference to any one or more of the drawings.
According to a further aspect the invention consists in a reactor ntially as
herein described and with reference to any one or more of the drawings.
Accordingly, in a further aspect the t invention may broadly be said to
be a method of monitoring and/or ining the temperature of a reformer tube
in a reformer r, the method comprising measuring the change in length of the
tube.
The t invention may also broadly be said to be a method of monitoring
temperature distribution in a reformer reactor that includes a plurality of distributed
tubes, the method comprising measuring the change in length of at least some of
the tubes.
The present invention also may broadly be said to be a method of monitoring
and/or determining the change in temperature of a reformer tube in a reformer
reactor, the method comprising measuring the change in length of the tube.
The present invention also may broadly be said to be a method of monitoring
and/or determining the change in temperature of a reformer tube in a reformer
r, the method comprising measuring thermal expansions/contraction of the
length of the tube.
The present ion also may y be said to be a monitoring and/or
determining the change in length of a reformer tube in a reformer reactor as a
correlation of a temperature change or changes of the tube.
The present ion also may broadly be said to be a monitoring and/or
determining the temperature bution in a reformer reactor that has a plurality
of distributed reformer tubes, by measuring thermal ion/contraction of a
ity of said reformer tubes.
Preferably the measuring is done by a gauge.
The present invention may also broadly be said to be a monitor for monitoring
and/or determining temperature of a reformer tube in a reformer reactor, the
r comprising a gauge capable of measuring the change in length of the tube.
The present invention may also broadly be said to be a monitor for monitoring
and/or determining temperature distribution in a reformer reactor that has a
plurality of distributed reformer tubes, the monitor comprising at least one gauge
capable of ing the change in length of a plurality of the tubes in the reactor.
Preferably a gauge is provided for each tube to be measured.
The present invention may also y be said to be a monitor for monitoring
for overheat of a reformer tube in a reformer reactor by measuring a temperature
dependent change in length said reformer tube.
The present invention may also broadly be said to be a monitor for ring
for overheat of a er tube in a reformer reactor by measuring a temperature
dependent change in length said reformer tube, the monitor sing a gauge
capable of measuring the change in length of a tube.
The present invention may also y be said to be a monitor for monitoring
and/or measuring a change in temperature of a reformer tube in a reformer
reactor, the monitor comprising a gauge capable of ing the change in length
of a tube.
ably the gauge is able to transmit change in length information.
Preferably the gauge is able to transmit change in length information to a receiver.
Preferably the receiver can cause change in length information to be displayed.
Preferably the receiver can cause change in length information to be stored.
Preferably the receiver can cause change in length information to be accumulated.
Preferably the monitor comprises a plurality of gauges, each dedicated to a tube of
the reactor, each gauge able to transmit change in length ation to a receiver.
Preferably the receiver can cause change in length information to be displayed for
each tube.
Preferably the receiver can cause the change in length information to be displayed
for each tube in a manner reflecting the location of the tubes when seen in plan
view, in the reactor.
Preferably the display relies on colour to show change in length information of each
tube.
_10_
ably the display allows a person to determine the temperature of each tube in
the reactor.
Preferably the reformer as herein above described is a steam reformer.
ably the steam reformer is used in the process of producing methanol.
The term “comprising” as used in this specification means “consisting at least
in part of”. When interpreting each statement in this specification that includes the
term ising”, features other than that or those prefaced by the term may also
be present. Related terms such as “comprise” and “comprises” are to be
interpreted in the same manner.
The invention consists in the foregoing and also envisages uctions of
which the following gives examples only.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will be described by way of example
only and with reference to the gs, in which:
Figure 1 is a simplified view of a reformer reactor, and
Figure 2 is a thermal image representation of temperature distribution of the
reformer reactor as seen in plan view.
DETAILED PTION
Over heat protection and process optimisation
The present invention includes a method and apparatus for ring for
overheat of individual tubes and/or of temperature distribution in a reformer
reactors such as a steam reformer, preferably but not solely for the process of
making methanol. Alternative applications of this invention may be in the reformer
stage of hydrogen or ammonia.
By way of e, a reactor 1 is shown in Figure 1 and includes an enclosure
2 that houses a plurality of reformer tubes 3. For the production of methanol, a
natural gas and water mixture moves through heated tubes. Each tube contains
nickel oxide (NiO) catalyst. This allows an endothermic reforming reaction to occur.
Heat is typically provided to the reformer furnace via a number of burners. For
example, a burner may be located near every tube, or a group of tubes such that
there is imately 1 burner per 4 to 6 tubes on average.
The r may e sight ports 4, as bed above for ting the
reformer and/or measurement of er tube temperature.
To measure the temperature of the tubes, it is not le to obtain a direct
measurement clue to the extremely high temperature within the reformer. For
example, the tubes are at a temperature typically in excess of 900°C, while the flue
gas may exceed 1000° C. Further, the nature of the reforming reaction, and the
distribution of g burners etc, can result in a complex distribution of
temperature along the length of the tubes and through the walls of the tubes.
In order to obtain an indicative measure of the temperature of the tubes, the
present invention employs a measuring gauge. This measuring gauge will measure
the thermal expansion and contraction of a tube, or each tube in the reactor. More
particularly, in the most preferred configuration, the elongation of the reformer
tubes are directly measured by the measuring gauges.
In a preferred embodiment a number of reformer tubes may be hung off a
single hanger, and a single measuring gauge utilised to measure the change in
length due to thermal expansion and contraction of a plurality of tubes hung from
the same . For example, a single hanger may support a pair of tubes, or four
tubes, or more. This configuration has an advantage of ng the number of
measuring gauges required.
It is to be understood that references in this specification and claims to
"measuring a reformer tube", is intended to encompass the measuring of a single
tube, or a plurality of tubes hanging from a single support. Similarly, the term
"measuring" and/or "measurement" is intended to encompass the described
-12_
configuration of measuring the longitudinal extension of a single tube, or a group of
tubes, ted on a single hanger.
Accordingly, each gauge arranged in this way measures an 'average' of sorts,
of the change in length of all the tubes on the hanger. From this change in length, a
normalised indicative temperature can be calculated. It is to be understood that
references to measuring "temperature" in this specification and claims, is intended
to mean measurement of the 'normalised' or 'indicative' temperature as described
herein.
Further, throughout the reformer, the number of tubes supported by each
hanger may be different. For example, some hangers may support four tubes while
others support a pair of tubes or only one tube.
It has been found that measuring the change in length of a group of tubes
works well, particularly when those tubes are in close proximity to each other and
ence a similar environment within the reformer furnace.
atively, each tube in the reformer may be mented so that its
change in length can be measured. Such use may be to display, length, a change in
length of the tube directly, or a calculated temperature based on the ed
displacement data. It is most preferred that every tube in the reformer r as
instrumented either individually, or as part of a group of tubes on the same hanger
for example. Alternatively, only a selection of tubes may be instrumented
throughout the reformer. In this situation, it is preferred that the tubes are
distributed throughout the reformer. It is also preferred that the majority of tubes
are instrumented (either individually, or as part of a group as bed).
It is most preferred that the measurement gauges are configured to provide
data in real time with an appropriate sample interval. For example, a sample rate of
between 1-3 data points per minute, and one data point per 24 or 48 hours, is
preferred. For a relatively slow moving process, sample rates faster than 1 per
minute, are not likely to icantly increase the benefit. Each measurement
gauge is configured to communicate with a computerised ring and/or control
system to receive, record, and store the measured data. The measuring devices are
preferably configured to communicate wirelessly with one or more receivers, which
can relay the information back to a monitoring .
The use of the change in length of the tube to calculate a ised
temperature, will result in an approximation of temperature across the entire length
of the tube, rather than a specific accurate temperature at any given point. It will
be appreciated that the present method can be supplemented by more traditional
_13_
inspections of the er tubes (via ter for example), to further identify
hotspots along the length of a reformer tube, that requires remedial trimming.
It has been found however, that the 'approximation' of tube ature by
ing the change in length of the tube (or tubes on a hanger) is more than
sufficient for the present purposes. In ular, this method of measuring the
change in length of the tubes has been found to be sensitive enough to detect
abnormal tube heating and/or cooling. Such al temperature, can affect the
efficiency of the process, or in the case of overheating, if left unchecked can
significantly affect the life of the reformer tube(s), and in worst—case scenarios may
lead to reformer burnout.
The measuring gauge may be a laser ce gauge or another means. It
may for example measure the cement of one end of a tube (or hanger
supporting a multitude of tubes), the other end being held fixed relative so some
datum that the gauge is fixed to also. As a tube heats up, it lengthens. This is
measured by the gauge. This length measurement is then used subsequently to
calculate a ature using techniques known in the art. For example, an
equation for linear thermal expansion tells us that the change in length of the tube
is directly proportional to the change in temperature. However, it is known that the
coefficient of growth is not constant, but rather changes with temperature.
Therefore, a linear approximation may be made using a cient of growth
appropriate for typical operating temperatures.
Alternatively, a non—linear correlation between growth and temperature can
be used, as is known.
Based on intervening calculations/processing, the measurement may
additionally be represented graphically. Such a graphic display may be in the form
of a l image map as shown in figure 2. Thermal 'maps' have been found to
provide an excellent visual indication of temperature distribution within the
reformer, as well as 'hot spots' and/0r 'cold spots'.
The Thermo map is useful in the operations control room and/or may also be
ble on a mobile device. Further, a real time live Thermo map may be
wirelessly (or otherwise) transmitted to a tablet for example. The trimmer can then
take the tablet around the furnace and use the information (graphically displayed)
and/or otherwise displayed, to trim the burner valves. The use of real-time
information at the time of trimming allows the trimmer to quickly see the effect of
the trimming changes made. As a result the reformer ency may be improved.
The map is indicative of the temperature, derived from the gauge, of each
tube at locations corresponding to where each tube exists in the reformer reactor.
-14_
The area 3A is for example an area corresponding to where a er tube is
located in the reactor. The image map boundary 2A being indicative of the
ure 2 of the reactor as seen in plan. For ng purposes, it is very helpful
to have information about the location within the reformer reactor of any hotspots
or cold spots. More particularly, it is ary to know which burners to trim in
order to normalise those hotspots and/or cold spots.
Any false reading may show up as an area 38. Such thermal maps, can be
very useful for staff in operations to visualise how the reformer is behaving.
With the invention every tube (or group of tubes instrumented) is being
measured in real time. This can allow for fast detection of reformer tubes
overheating or cooling.
The operations management preferably control the burners in an effort to maintain
a relatively even temperature throughout the entire reformer by trimming. A well
trimmed reformer will generally result in the highest efficiency of the reforming
process, by ating cold spots which contribute to methane slip. uently,
a real time data stream of ised temperature readings is an extremely
valuable tool for keeping the reformer trimmed appropriately.
In particular, the present system reduces the reliance on significant
manpower and time delay ed in manually measuring reformer tube
temperatures with a pyrometer through sight ports, and then adjusting the burner
trims appropriately. The present system enables trimming decisions to be made at
any time, and as often as is considered necessary, t the need to first execute
the time-consuming process of a manual temperature shoot (which make typically
take approximately an hour and be done only a few times in a 24 hour period). It is
considered that the present system is an important step, because it enables that
least some burner trimming to be automated as an alternative to manual trimming.
The t method allows the reformer to be run with higher efficiency
levels. As noted previously, traditional pyrometer temperature measurement can
still be used to identify hotspots which may not be picked up by the t system
so that trimming adjustments can be made accordingly.
Measuring change in temperature can also allow for early g of possible
overheat. Small levels of overheat in individual tubes can have a significant
ental effect on the life of that tube. Further, if a more l and severe
overheating situation occurs throughout the reformer or in a significant region of
the reformer, there is a risk of burnout.
The system may include an alarm that triggers when a certain predetermined
limit is reached. For example, if one or more reformer tubes are found to exceed a
predetermined limit, an alarm can be triggered to inform the operations control that
action is required. Adjustment of the temperature of the tube can then be effected,
by trimming the burners in the vicinity of the overheated tube or tubes, or if
necessary more aggressive action.
The alarm predetermined limit may be a distance Le. a length of the tube (or
group of tubes on a single hanger), that if reached, will trigger the alarm.
Alternatively, the predetermined alarm limit, may be a temperature Le. a
ated normalised temperature of the tube (or group of tubes on a single
), that if d will trigger the alarm.
It is envisaged that each tube (or each group of tubes on a single hanger),
may have a different alarm trigger calculated and applied. The different threshold
may be based on the creep history experienced by that tube (or group of tubes),
or any other reason why the target temperature for a tube, may be different from
another tube.
Further, the alarm predetermined limit may be adjusted over time to reflect
the expected creep of the tubes 'normal' length over time. That is, it is to be
ed that over the course of several years of service, the length of a tube at a
given temperature will change due to creep. The amount of creep can be relatively
accurately predicted over time using known techniques, and ore the alarm
threshold limits can be ically altered to t this ed change. In
particular, after a reformer shut down, accurate actual measurements can be taken
of the tubes to verify the amount of creep damage that is actually occurred. This
information can be used to recalibrate the alarm trigger threshold for the tube.
Real-time measurement of an indicative temperature (for each tube or for a
number of groups of tubes), allows the operations team to react much more quickly
to situations which could lead to partial or full t of the reformer. As a result,
the risk of such a catastrophic event (which can typically cost tens of millions of
dollars), can be significantly reduced. This reduction of risk and have very
significant positive effects on the expenses and profitability of a reformer operation.
It is envisaged that a number of predetermined alarm limits may be
implemented at differing degrees of temperature ality. For example, a first
alarm may be triggered if a tube (or group of tubes) reaches a first predetermined
limit substantially as described above. The first predetermined limit may represent
a threshold where the operations team should consider ng the appropriate
burners when the next trimming cycle is due for e.
In addition, a second alarm may be triggered at a second predetermined limit,
that represents a higher threshold where action should be taken more quickly to
-16—
improve the efficiency of the reformer and/or avoid ssary creep damage
caused by overheated.
Further, a third alarm may be red at a third predetermined limit that
represents the need for urgent drastic action to prevent the reformer from ng
a high risk burnout scenario. For example, ting the main gas pressure down,
is a typical response to a dangerous event such as a number of tubes, ng
attempt above a predetermined threshold. A fourth alarm criteria is envisaged to
trigger if a predetermined number of tubes (or a predetermined percentage of the
tubes in the reformer) exceed a predetermined temperature threshold.
It is envisaged that any of the alarms bed may be visual or audible. For
example, a light may flash or an audible sound may be generated. Typically the
alarms would se in severity due to the nature of the alarm event.
In particular, a visual alarm overlaid on the thermal map is envisaged where
one or more tubes indicating a temperature above a predetermined threshold, may
flash for example. This would draw attention to the relevant locations on the
thermal map, for remedial action.
Tube life management
Data can also be collected of temperature profile each tube has been
subjected to over time. This may be able to be given an average value based on
average temperature the tube has been subjected to for a given duration by virtue
of its elongation measures. A tive value can then show the degree of creep
that the tube has been subjected to and therefore a real live measure of each
individual tube’s likely remaining life span may be able to be determined. The life of
a tube is typically measured by the change in diameter of the tubes. For example, it
may be considered that a tube has reached the end of its life when the diameter
has increased by a predetermined tage (e.g. 3% increase in internal
diameter). Known techniques for correlating change in tube length and/or tube
ature y to tube diameter creep can be utilised. These techniques may
be based on models and/or empirical correlations.
For example, the monitoring system may periodically calculate a measure of
tube life consumed based on the cumulative temperature data over time
experienced for each tube (or group of tubes instrumented on a single hanger).
This information can then be used to determine likely failure time is for the tubes.
It will be appreciated that this data is extreme is useful for logistical planning
purposes around scheduled shutdowns etc.
There are a number of known techniques in the art for ating expected
failure and/or life consumed, based on nmental conditions experienced by
ures subjected to high pressures and temperatures. However, up until now
the estimates can be unreliable because of the quality of the data ble to feed
into the predictive . In particular, the quality of the temperature data over
the life of the er tubes has been lacking. It is known that the creep life of
reformer tubes is extremely sensitive. For example, a 20°C increase in temperature
(i.e. 930° versus 950°) will approximately halve the expected life. Therefore, even
short periods of overheating can significantly reduce life expectancy. Short-term
temperature fluctuations are not necessarily even picked up by ional manual
temperature measurement techniques. As a result any predictive technique based
on that data will underestimate the life consumed, which could lead to early failure,
and an unscheduled shutdown of the reformer.
The present invention greatly improves the frequency of temperature data
available for individual tubes (or groups of tubes) over its entire life. Accordingly,
the predictive models which correlate temperature data to stress, and creep, are
able to deliver significantly improved results.
—18—
Claims (9)
1. A method of monitoring the temperature of a reformer tube in a er reactor comprising: measuring the length of said tube, calculating said temperature using said measured length.
2. The method of monitoring as claimed in claim 1, wherein measuring said length of said tube comprises measuring the displacement of a hanger supporting said tube.
3 The method of monitoring as claimed in claim 2, whereinsaid hanger supports a plurality of tubes.
4. The method of monitoring as d in any one of claims 1 to 3, wherein said measuring of length occurs over time, and a change in length over time is calculated.
5. The method of monitoring as d in any one of claims 1 to 4, wherein said said measuring of length occurs over time, and a change in temperature over time is calculated from said change in length over said time.
6. A method of monitoring ature distribution in a reformer reactor that includes a plurality of distributed tubes, comprising: using the method of any one or more of claims 1 to 6, to measure at least some of said tubes.
7. The method of monitoring of claim 6, wherein the majority of said tubes in said reformer are monitored.
8. The method of ring of any one of claims 1 to 7, n said measuring the length of said tube is done autonomously by a displacement transducer.
9. The method of monitoring of claim 8, wherein said displacement transducer transmits measurement data wirelessly to a receiver. _19
Publications (1)
Publication Number | Publication Date |
---|---|
NZ616596B2 true NZ616596B2 (en) | 2015-07-28 |
Family
ID=
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU2013328247B2 (en) | Tube monitor and process measurement and control in or for a reformer | |
JP5881814B2 (en) | Method for predicting the remaining useful life of an engine and its components | |
JP6037954B2 (en) | Boiler tube leak detection device, boiler tube leak detection method, data monitoring center using these, information providing service, and boiler plant. | |
AU2014371824B2 (en) | Heat transfer tube life estimating system | |
JP2014051971A (en) | Creep life management system for turbine engine and method of operating the same | |
EP3743169B1 (en) | System and method for low point monitoring in a fire suppression system | |
US9797786B2 (en) | Device for calibrating temperature, and methods for calibrating the temperature of and positioning a fiber-optic temperature sensor | |
US8355891B2 (en) | Method of replacing the catalyst tubes of a hydrocarbon reformer | |
US11255823B2 (en) | Steam/hot water device monitoring | |
WO2019203696A1 (en) | Method and system for evaluating the technical condition of gas turbine assemblies | |
AU2021405997A1 (en) | Method for monitoring a slip-ring seal assembly, and slip-ring seal assembly | |
NZ616596B2 (en) | Tube monitor and process measurement and control in or for a reformer | |
US20200333274A1 (en) | Monitoring of heated tubes | |
JP2016166781A (en) | Monitoring system and method of scale in pipeline | |
US9696092B2 (en) | Furnace cooling panel monitoring system | |
Lehmann | Fixed-point thermocouples in power plants: long-term operational experiences | |
JP5022018B2 (en) | Gas turbine monitoring device | |
US10767980B2 (en) | Method of determining diametrical growth of reformer tubes | |
RU2664891C1 (en) | Method of estimation pipe remaining service life | |
JP2023008132A (en) | Damage evaluation device and method | |
KR101127477B1 (en) | Apparatus of Temperature Sensor for A Gas Turbine | |
KR20190024183A (en) | Maintenance system of gas turbine power generation system |