EP0753701B1 - Boiler with denitrification apparatus - Google Patents
Boiler with denitrification apparatus Download PDFInfo
- Publication number
- EP0753701B1 EP0753701B1 EP19960110432 EP96110432A EP0753701B1 EP 0753701 B1 EP0753701 B1 EP 0753701B1 EP 19960110432 EP19960110432 EP 19960110432 EP 96110432 A EP96110432 A EP 96110432A EP 0753701 B1 EP0753701 B1 EP 0753701B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- temperature
- economizer
- denitrification apparatus
- boiler
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000001105 regulatory effect Effects 0.000 claims description 15
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
- 239000007789 gas Substances 0.000 description 31
- 239000000295 fuel oil Substances 0.000 description 19
- 238000010438 heat treatment Methods 0.000 description 16
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 15
- 239000003546 flue gas Substances 0.000 description 15
- 238000010304 firing Methods 0.000 description 11
- 239000012717 electrostatic precipitator Substances 0.000 description 10
- 238000005260 corrosion Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 5
- 238000010276 construction Methods 0.000 description 5
- 230000007774 longterm Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 239000004071 soot Substances 0.000 description 4
- WWILHZQYNPQALT-UHFFFAOYSA-N 2-methyl-2-morpholin-4-ylpropanal Chemical compound O=CC(C)(C)N1CCOCC1 WWILHZQYNPQALT-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical group [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 150000003682 vanadium compounds Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/006—Layout of treatment plant
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B37/00—Component parts or details of steam boilers
- F22B37/008—Adaptations for flue gas purification in steam generators
Definitions
- the present invention relates to a boiler as defined in the preamble portion of claim 1, for firing a heavy oil (including high viscosity residual oil, super heavy oil (Orinoco oil, for example) and water emulsion fuel), etc.
- a heavy oil including high viscosity residual oil, super heavy oil (Orinoco oil, for example) and water emulsion fuel
- Heavy oil contains a high amount of nitrogen content and sulfur content as compared with the usual C fuel oil. For this reason, in order to use such heavy oil for boilers under the environment regulations, there are many cases where installation of a denitrification apparatus or a desulfurization apparatus is required for reducing NOx density or SOx density in the flue gas.
- Fig. 7 shows a diagrammatic view of a heavy oil firing boiler in the prior art, wherein numeral 1 designates a furnace, and on the downstream side of the furnace 1, there are provided a superheater 2, a reheater 3, an economizer 4A, a denitrification apparatus 6, an air preheater 8, an electrostatic precipitator 10, a gas-gas heater 11 and a desulfurization apparatus 12, in turn.
- Numeral 15A designates an economizer gas by-pass duct and numeral 16A designates a flow regulating damper interposed in the economizer gas by-pass duct 15A.
- heavy oil contains a high amount of heavy metals, such as vanadium, nickel, etc. and in a heavy oil firing boiler having a denitrification apparatus, a vanadium compound, in addition to SO 3 generated at the combustion zone, covers the surface of NOx removal catalysts so as to act as an oxidation catalyst, thus conversion ratio of SOx to SO 3 becomes also higher.
- heavy metals such as vanadium, nickel, etc.
- a vanadium compound in addition to SO 3 generated at the combustion zone, covers the surface of NOx removal catalysts so as to act as an oxidation catalyst, thus conversion ratio of SOx to SO 3 becomes also higher.
- the flue gas temperature also becomes high, and if it exceeds approximately 180°C, the ammonium injected at the inlet of the electrostatic precipitator for SO 3 removal is resolved to generate an ammonium hydrogen sulfate of low melting temperature, thereby ash clogging or corrosion, or in some cases a charging obstruction, might be caused, hence the elevation of the flue gas temperature as time passes must be suppressed as much as possible.
- a boiler comprising a high temperature economizer and a low temperature economizer and a denitrification apparatus arranged therebetween as well as a damper regulated bypass around the high temperature economizer is disclosed in US-A-5 423 272 and in FR-A-2 360 045.
- the present invention has following features:
- the denitrification apparatus can be operated at an optimized operational temperature and further the heat recovery proportion of the economizers and the air preheater can be selected without being influenced by the operational temperature of the denitrification apparatus, hence the temperature effectiveness of the air preheater can be maximized and economical operation becomes possible.
- the heating area of the low temperature economizer can be set in surplus based on the heat transfer coefficient taking account of dirt, and by the gas amount by-passing the low temperature economizer being regulated correspondingly to the degree of dirt of the low temperature economizer, the gas temperature at the outlet of the air preheater and the gas temperature at the outlet of the electrostatic precipitator can be maintained within an appropriate range, hence a long term continuous and stable operation becomes possible.
- the heating area of the high temperature economizer can be set in surplus based on the heat transfer coefficient taking account of dirt, and by the gas amount by-passing the high temperature economizer being regulated correspondingly to the degree of dirt of the high temperature economizer, the operational temperature of the denitrification apparatus, the gas temperature at the outlet of the air preheater and the gas temperature of the electrostatic precipitator can be maintained within an appropriate range, hence a long term continuous and stable operation becomes possible.
- Fig. 1 is a diagrammatic view of a boiler of a first example for explaining certain features of the present invention.
- Fig. 2 is a diagrammatic view of a boiler of a second example for explaining certain features of the present invention.
- Fig. 3 is a graph showing time passing changes of gas temperature at an inlet of a denitrification apparatus of heavy oil firing boilers.
- Fig. 4 is a diagrammatic view of a boiler of a preferred embodiment according to the present invention.
- Fig. 5 is a graph showing time passing changes of gas temperature at an outlet of an air preheater of heavy oil firing boilers.
- Fig. 6 is a diagrammatic view of a boiler of a further preferred embodiment according to the present invention.
- Fig. 7 is a diagrammatic view of a heavy oil firing boiler in the prior art.
- FIG. 1 A first example for explaining certain features of the present invention is described with reference to Fig. 1.
- This example relates to a modification, as herebelow, of the boiler shown in Fig. 7, and same parts of Fig. 1 as those of Fig. 7 are designated by same numerals and description thereof is omitted.
- the economizer is divided into that on the upstream side and that on the downstream side of the denitrification apparatus 6, that is, the economizer is divided into a high temperature economizer 4 and a low temperature economizer 7 and the high temperature economizer 4 is disposed on the upstream side of the denitrification apparatus 6 and the low temperature economizer 7 on the downstream side of same, respectively.
- the economizer by-pass duct 15A in the boiler shown in Fig. 7 is not provided.
- the denitrification apparatus 6 can be maintained at an appropriate operational temperature and the temperature effectiveness of the air preheater can be maximized so that economical operation can be made.
- FIG. 2 A second example for explaining certain features of the present invention is described with reference to Fig. 2.
- the heating area of the high temperature economizer 4 is set in surplus, a high temperature economizer gas by-pass duct 15 by-passing said high temperature economizer 4 is provided and a flow regulating damper 16 is interposed in said high temperature economizer gas by-pass duct 15.
- the denitrification apparatus can be controlled at a temperature at which the right performance can be effected. Further, as shown by the line in Fig. 3, with respect to the time passing elevation also of the gas temperature due to the dirt of the heating surface, the elevation of the flue gas temperature can be suppressed by the effect of said surplus heating area of the high temperature economizer 4 and'a long term continuous and stable operation can be made possible.
- FIG. 4 A preferred embodiment according to the present invention is described with reference to Fig. 4.
- the heating area of the low temperature economizer 7 is set in surplus, a low temperature economizer by-pass duct 18 by-passing said low temperature economizer 7 is provided and a flow regulating damper 19 is interposed in said low temperature economizer by-pass duct 18.
- the heating area of the low temperature economizer 7 on the downstream side of the denitrification apparatus 6 being set in surplus and by the gas flow by-passing the low temperature economizer 7 and flowing through the low temperature economizer by-pass duct 18 being regulated and mixed into the outlet portion of the low temperature economizer 7, as shown by the line in Fig. 5, the time passing elevation of the gas temperature at the outlet of the air preheater 8, or the gas temperature at the inlet of the electrostatic precipitator 18, due to the dirt of the heating surface of said low temperature economizer 7 can be suppressed by the effect of the surplus heating area of this low temperature economizer 7.
- FIG. 6 A further preferred embodiment according to the present invention is described with reference to Fig. 6.
- This preferred embodiment comprises a combination of a high temperature economizer 4 and a high temperature economizer by-pass duct 15 having a flow regulation damper 16, as in said second example, and a low temperature economizer 7 and a low temperature economizer by-pass duct 18 having a flow regulating damper 19, as in said above mentioned preferred embodiment according to the present invention.
- the denitrification apparatus 6 can be controlled at a temperature at which the right performance can be effected and yet with respect to the time passing elevation of the gas temperature due to the dirt of the heating surface also, the elevation of the flue gas temperature can be suppressed by the effect of the surplus heating area of this high temperature economizer 4 and a long term continuous and stable operation can be made.
- the denitrification apparatus can be operated in the range of the maximized operational temperature, the temperature of the air preheater and the electrostatic precipitator on the downstream side can be made appropriate and a long term continuous and stable operation can be made possible.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chimneys And Flues (AREA)
- Treating Waste Gases (AREA)
- Air Supply (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Description
The present invention relates to a boiler as defined in the preamble portion of claim 1, for firing
a heavy oil (including high viscosity residual oil, super
heavy oil (Orinoco oil, for example) and water emulsion
fuel), etc.
Heavy oil contains a high amount of nitrogen
content and sulfur content as compared with the usual C fuel
oil. For this reason, in order to use such heavy oil for
boilers under the environment regulations, there are many
cases where installation of a denitrification apparatus or
a desulfurization apparatus is required for reducing NOx
density or SOx density in the flue gas.
Fig. 7 shows a diagrammatic view of a heavy oil
firing boiler in the prior art, wherein numeral 1 designates
a furnace, and on the downstream side of the furnace 1,
there are provided a superheater 2, a reheater 3, an
economizer 4A, a denitrification apparatus 6, an air
preheater 8, an electrostatic precipitator 10, a gas-gas
heater 11 and a desulfurization apparatus 12, in turn.
Numeral 15A designates an economizer gas by-pass duct and
numeral 16A designates a flow regulating damper interposed
in the economizer gas by-pass duct 15A.
In the denitrification apparatus employed for
such construction, it is a main tendency to use a dry type
catalytic reduction process for a problem of NOx removal
efficiency etc., but if heavy oil is fired, as a high amount
of SOx is contained in the flue gas, in case the flue gas
temperature becomes low for reason of a partial load etc.,
there is a fear of lowering of catalyst activation due to
generation of ammonium hydrogen-sulfate etc., hence a method
to maintain the denitrification apparatus within an appropriate
temperature range by making a gas by-pass of a
portion of the flue gas entering the economizer is employed.
In addition to the fact that heavy oil contains
a high amount of nitrogen content and sulfur content as
compared with the usual C fuel oil, due to its high residual
carbon, soot and dust generated by combustion tends to
become a large amount also. For this reason, progress of
dirt on the heating surface is very quick and in some cases
the flue gas temperature rises sharply after starting of
operation, thus it is necessary to pay attention to thermal
resistance of NOx removal catalysts, design temperature of
each portion, etc.
Further, heavy oil contains a high amount of heavy
metals, such as vanadium, nickel, etc. and in a heavy oil
firing boiler having a denitrification apparatus, a vanadium
compound, in addition to SO3 generated at the combustion
zone, covers the surface of NOx removal catalysts so as to
act as an oxidation catalyst, thus conversion ratio of SOx
to SO3 becomes also higher.
This reaction tends to be more accelerated as
the gas temperature becomes higher and yet if SO3 density
becomes higher, low temperature corrosions or blockades of
the air preheater, or increase of soot and dust at the inlet
of the electrostatic precipitator, etc. occur, hence in
order to avoid troubles of machinery and equipment on the
downstream side also, it is necessary to suppress the
operational temperature of the denitrification apparatus
approximately to 40°C.
But in case of the steam temperature being high,
additives like a magnesium group etc. are often injected as
a countermeasure to prevent high temperature corrosions of
the superheater or the reheater, and due to dirt of the
furnace surface, the heat absorption becomes lowered so that
the gas temperature at the furnace outlet becomes high, thus
the gas temperature of each portion is liable to be
elevated.
On the other hand, if the gas temperature at
the inlet of the denitrification apparatus becomes too low,
ammonium hydrogen-sulfate is generated, as mentioned above,
so that a problem of lowering of catalyst activation etc.
occurs, hence it is necessary to maintain the gas
temperature higher than approximately 360°C.
Accordingly, in a heavy oil firing boiler, as the
range of the appropriate flue gas temperature is as narrow
as approximately 360°C to 400°C, how to control this gas
temperature, taking into account of the time passing or
aging changes also, is important for a continuous stable
operation.
Such problems as mentioned above exist likewise
in respect to the gas temperature at the inlet of the
electrostatic precipitator also. In a heavy oil firing
boiler, as SO3 density in the flue gas is high, an air
heater of regenerative type is usually employed and elements
of high corrosion resistant materials and of such shapes as
having good effects for soot blowing are employed as a
countermeasure for low temperature corrosions or blockades,
but it is still necessary to operate the metal temperature
on the low temperature side at a temperature considerably
higher than in the C fuel oil firing, or to install a steam
type air preheater additionally. Accompanying therewith,
the flue gas temperature also becomes high, and if it
exceeds approximately 180°C, the ammonium injected at the
inlet of the electrostatic precipitator for SO3 removal is
resolved to generate an ammonium hydrogen sulfate of low
melting temperature, thereby ash clogging or corrosion, or
in some cases a charging obstruction, might be caused, hence
the elevation of the flue gas temperature as time passes
must be suppressed as much as possible.
In the construction of the above-mentioned heavy
oil firing boiler in the prior art, as the allotment of the
heat recovery at the economizer 4A and the air preheater 8
is decided by the operational temperature of the denitrification
apparatus 6, in case of the flue gas temperature
being lowered due to a partial load etc., it is possible to
maintain the denitrification apparatus 6 at a most suitable
operational temperature by letting a partial gas by-pass
the economizer, but in case of elevation of the operational
temperature, there is no means other than strengthening of
soot blowing on the heating surface, etc.
Further, as the installation temperature of the
denitrification apparatus 6 is comparatively high and the
heat recovery proportion of the air preheater 8 thus becomes
larger, the temperature effectiveness also becomes high and
the heating area of the air preheater tends to be increased.
In respect of elevation of the gas temperature at the inlet
of the electrostatic precipitator 10 also, countermeasures
are being taken by lowering the metal temperature on the low
temperature side of the air preheater 8 in fear of low
temperature corrosions or blockades.
Thus, in the construction of the heavy oil firing
boiler in the prior art, as shown by the dashed line in Fig.
3, in case of elevation of the flue gas due to dirt of the
furnace or the heating surface, no control being able, the
boiler is operated with a lowered load or there is
occasionally such case that the boiler is unavoidably shut
down within a short period of time.
A boiler comprising a high temperature economizer and a
low temperature economizer and a denitrification apparatus
arranged therebetween as well as a damper regulated bypass
around the high temperature economizer is disclosed in US-A-5
423 272 and in FR-A-2 360 045.
It is therefore an object of the present invention to
provide a boiler which is able to dissolve the above
mentioned problems.
The present invention has following features:
In the invention mentioned in (1) and (2) above, by the
economizer being divided into the high temperature economizer
and the low temperature economizer disposed, respectively, on
the upstream side and on the downstream side of the
denitrification apparatus, the denitrification apparatus can
be operated at an optimized operational temperature and
further the heat recovery proportion of the economizers and
the air preheater can be selected without being influenced by
the operational temperature of the denitrification apparatus,
hence the temperature effectiveness of the air preheater can
be maximized and economical operation becomes possible.
Furthermore, by the duct by-passing the low temperature
economizer being provided and the flow regulating damper
beinq interposed in said duct, the heating area of the low
temperature economizer can be set in surplus based on the
heat transfer coefficient taking account of dirt, and by the
gas amount by-passing the low temperature economizer being
regulated correspondingly to the degree of dirt of the low
temperature economizer, the gas temperature at the outlet of
the air preheater and the gas temperature at the outlet of
the electrostatic precipitator can be maintained within an
appropriate range, hence a long term continuous and stable
operation becomes possible.
Further, in the embodiment of the invention of (3)
above, by the duct by-passing the high temperature economizer
being provided and the flow regulating damper being
interposed in said duct, the heating area of the high
temperature economizer can be set in surplus based on the
heat transfer coefficient taking account of dirt, and by the
gas amount by-passing the high temperature economizer being
regulated correspondingly to the degree of dirt of the high
temperature economizer, the operational temperature of the
denitrification apparatus, the gas temperature at the outlet
of the air preheater and the gas temperature of the
electrostatic precipitator can be maintained within an
appropriate range, hence a long term continuous and stable
operation becomes possible.
In the accompanying drawings:
Fig. 1 is a diagrammatic view of a boiler of a first
example for explaining certain features of the present
invention.
Fig. 2 is a diagrammatic view of a boiler of a second
example for explaining certain features of the present
invention.
Fig. 3 is a graph showing time passing changes of gas
temperature at an inlet of a denitrification apparatus of
heavy oil firing boilers.
Fig. 4 is a diagrammatic view of a boiler of
a preferred embodiment according to the present
invention.
Fig. 5 is a graph showing time passing changes of
gas temperature at an outlet of an air preheater of heavy
oil firing boilers.
Fig. 6 is a diagrammatic view of a boiler of
a further preferred embodiment according to the present
invention.
Fig. 7 is a diagrammatic view of a heavy oil
firing boiler in the prior art.
A first example for explaining certain features of the
present invention is described with reference to Fig. 1.
This example relates to a modification, as
herebelow, of the boiler shown in Fig. 7, and same parts of
Fig. 1 as those of Fig. 7 are designated by same numerals
and description thereof is omitted.
In this example, the economizer is
divided into that on the upstream side and that on the
downstream side of the denitrification apparatus 6, that is,
the economizer is divided into a high temperature economizer
4 and a low temperature economizer 7 and the high
temperature economizer 4 is disposed on the upstream side
of the denitrification apparatus 6 and the low temperature
economizer 7 on the downstream side of same, respectively.
Incidentally, the economizer by-pass duct 15A in the boiler
shown in Fig. 7 is not provided.
In this example having the above-mentioned
construction, as the heat recovery proportion of
the low temperature economizer 7 and the air preheater 8 can
be selected without being influenced by the operational
temperature of the denitrification apparatus, the denitrification
apparatus 6 can be maintained at an appropriate
operational temperature and the temperature effectiveness
of the air preheater can be maximized so that economical
operation can be made.
A second example for explaining certain features of the
present invention is described with reference to Fig. 2.
In this example, in addition to the above-mentioned
first example,
the heating area of the high temperature
economizer 4 is set in surplus, a high temperature
economizer gas by-pass duct 15 by-passing said high
temperature economizer 4 is provided and a flow regulating
damper 16 is interposed in said high temperature economizer
gas by-pass duct 15.
In this example, by the heating area
of the high temperature economizer 4 on the upstream side of
the denitrification apparatus 6 being selected in surplus
taking account of the time passing dirt so that the
temperature becomes lower than the operational temperature
of the denitrification apparatus and by the by-passed high
temperature gas being regulated of the flow rate and mixed
into the inlet portion of the denitrification apparatus 6,
the denitrification apparatus can be controlled at a
temperature at which the right performance can be effected.
Further, as shown by the line in Fig. 3, with respect to the
time passing elevation also of the gas temperature due to
the dirt of the heating surface, the elevation of the flue
gas temperature can be suppressed by the effect of said
surplus heating area of the high temperature economizer 4
and'a long term continuous and stable operation can be made
possible.
Further, as to the elevation of the gas
temperature at the inlet of the electrostatic precipitator
10 also, it can be suppressed with same effect as mentioned
above.
On the other hand, also in case of the flue gas
temperature being lowered due to a partial load, by making
a gas by-pass through said high temperature economizer by-pass
duct 15, lowering of the flue gas temperature can be
prevented and the denitrification apparatus 6 can be
maintained at an appropriate operational temperature.
A preferred embodiment according to the
present invention is described with reference to Fig. 4.
In this preferred embodiment, in addition to said first
example,
the heating area of the low temperature economizer 7 is set
in surplus, a low temperature economizer by-pass duct 18 by-passing
said low temperature economizer 7 is provided and
a flow regulating damper 19 is interposed in said low
temperature economizer by-pass duct 18.
In this preferred embodiment, by the heating area
of the low temperature economizer 7 on the downstream side
of the denitrification apparatus 6 being set in surplus and
by the gas flow by-passing the low temperature economizer 7
and flowing through the low temperature economizer by-pass
duct 18 being regulated and mixed into the outlet portion of
the low temperature economizer 7, as shown by the line in
Fig. 5, the time passing elevation of the gas temperature at
the outlet of the air preheater 8, or the gas temperature at
the inlet of the electrostatic precipitator 18, due to the
dirt of the heating surface of said low temperature
economizer 7 can be suppressed by the effect of the surplus
heating area of this low temperature economizer 7.
A further preferred embodiment according to the
present invention is described with reference to Fig. 6.
This preferred embodiment comprises a combination of a high
temperature economizer 4 and a high temperature economizer
by-pass duct 15 having a flow regulation damper 16, as in
said second example,
and a low temperature economizer 7 and a low
temperature economizer by-pass duct 18 having a flow
regulating damper 19, as in said above mentioned preferred embodiment
according to the present invention.
Accordingly, in this preferred embodiment, there
are functions and effects of said second example
and said preferred embodiment being
combined, and the denitrification apparatus 6 can be
controlled at a temperature at which the right performance
can be effected and yet with respect to the time passing
elevation of the gas temperature due to the dirt of the
heating surface also, the elevation of the flue gas
temperature can be suppressed by the effect of the surplus
heating area of this high temperature economizer 4 and a
long term continuous and stable operation can be made.
As described above, according to the present
invention as having constructions mentioned in the Claims,
the denitrification apparatus can be operated in
the range of the maximized operational temperature, the
temperature of the air preheater and the electrostatic
precipitator on the downstream side can be made appropriate
and a long term continuous and stable operation can be made
possible.
Claims (2)
- A boiler comprising an economizer which is divided into a high temperature economizer (4) and a low temperature economizer (7) disposed, respectively, on the upstream side and on the downstream side of a denitrification apparatus (6),
characterized in that a duct (18) by-passing said low temperature economizer (7) is provided and a flow regulating damper (19) is interposed in said duct (18). - The boiler as claimed in claim 1, characterized in that a duct (15) by-passing said high temperature economizer (4) is provided and a flow regulating damper (16) is interposed in said duct (15) by-passing said high temperature economizer (4).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP176055/95 | 1995-07-12 | ||
| JP17605595 | 1995-07-12 | ||
| JP17605595A JPH0926105A (en) | 1995-07-12 | 1995-07-12 | Boiler |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0753701A1 EP0753701A1 (en) | 1997-01-15 |
| EP0753701B1 true EP0753701B1 (en) | 1999-09-01 |
Family
ID=16006936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19960110432 Expired - Lifetime EP0753701B1 (en) | 1995-07-12 | 1996-06-27 | Boiler with denitrification apparatus |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0753701B1 (en) |
| JP (1) | JPH0926105A (en) |
| CA (1) | CA2179002A1 (en) |
| DE (1) | DE69604027T2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014000977A1 (en) | 2012-06-27 | 2014-01-03 | Siemens Aktiengesellschaft | Exhaust-gas purification device and method for the reduction of nitrogen oxides from an exhaust gas of a fossil-fired power plant |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19929088C1 (en) * | 1999-06-24 | 2000-08-24 | Siemens Ag | Fossil fuel heated steam generator e.g. for power station equipment |
| EP1820560A1 (en) | 2006-02-16 | 2007-08-22 | Siemens Aktiengesellschaft | Steam Generator with catalytic coating of heat exchanger surfaces for exhaust gas purification |
| US20120222591A1 (en) | 2011-03-04 | 2012-09-06 | Foster Wheeler North America Corp. | Method of and Apparatus for Selective Catalytic NOx Reduction in a Power Boiler |
| JP5984731B2 (en) * | 2013-04-05 | 2016-09-06 | 三菱日立パワーシステムズ株式会社 | Denitration system |
| JP5624646B1 (en) * | 2013-05-23 | 2014-11-12 | 電源開発株式会社 | Thermal power plant and operation method of thermal power plant. |
| CN103994455A (en) * | 2014-04-04 | 2014-08-20 | 彭维明 | System and method for efficiently removing dust in flue gas of coal-fired power plant |
| CN103953914B (en) * | 2014-05-04 | 2016-04-06 | 国电龙源节能技术有限公司 | Boiler waste heat recovery system |
| EP3001102B1 (en) * | 2014-09-26 | 2020-10-28 | Stork Thermeq B.V. | A heat recovery unit and power plant |
| CN106931458A (en) * | 2017-02-27 | 2017-07-07 | 华北理工大学 | A kind of four bypass economizer high temperature bypath systems |
| CN110805918A (en) * | 2019-10-16 | 2020-02-18 | 华电电力科学研究院有限公司 | Device and method for blowing soot by using bypass flue gas |
| CN111911899A (en) * | 2020-07-10 | 2020-11-10 | 国家电投集团电站运营技术（北京）有限公司 | Boiler with function of preventing ammonium bisulfate of low-temperature economizer from being blocked |
| CN112050247A (en) * | 2020-09-28 | 2020-12-08 | 西安热工研究院有限公司 | System and method for low-load denitration of boiler |
| DE102021113713A1 (en) | 2021-05-27 | 2022-12-01 | Karl Schräder Nachf. Inh. Karl-Heinz Schräder e. K. | Device for cleaning the flue gases of a wood fuel fireplace |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5315639A (en) * | 1976-07-27 | 1978-02-13 | Hitachi Zosen Corp | Boiler has denitration device built-in |
| CA1092910A (en) * | 1976-07-27 | 1981-01-06 | Ko'hei Hamabe | Boiler apparatus containing denitrator |
| US4353207A (en) * | 1980-08-20 | 1982-10-12 | Westinghouse Electric Corp. | Apparatus for removing NOx and for providing better plant efficiency in simple cycle combustion turbine plants |
| JPS6283057A (en) * | 1985-10-09 | 1987-04-16 | Mitsubishi Heavy Ind Ltd | Electrostatic precipitator |
| US5423272A (en) * | 1994-04-11 | 1995-06-13 | Combustion Engineering, Inc. | Method for optimizing the operating efficiency of a fossil fuel-fired power generation system |
-
1995
- 1995-07-12 JP JP17605595A patent/JPH0926105A/en active Pending
-
1996
- 1996-06-12 CA CA 2179002 patent/CA2179002A1/en not_active Abandoned
- 1996-06-27 DE DE1996604027 patent/DE69604027T2/en not_active Expired - Lifetime
- 1996-06-27 EP EP19960110432 patent/EP0753701B1/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014000977A1 (en) | 2012-06-27 | 2014-01-03 | Siemens Aktiengesellschaft | Exhaust-gas purification device and method for the reduction of nitrogen oxides from an exhaust gas of a fossil-fired power plant |
| US9387436B2 (en) | 2012-06-27 | 2016-07-12 | Siemens Aktiengesellschaft | Exhaust-gas purification device and method for the reduction of nitrogen oxides from an exhaust gas of a fossil-fired power plant |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0753701A1 (en) | 1997-01-15 |
| JPH0926105A (en) | 1997-01-28 |
| DE69604027T2 (en) | 2000-02-24 |
| CA2179002A1 (en) | 1997-01-13 |
| DE69604027D1 (en) | 1999-10-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0753701B1 (en) | Boiler with denitrification apparatus | |
| EP1572327B1 (en) | System and method for controlling nox emissions from boilers combusting carbonaceous fuels without using external reagent | |
| CA2186369C (en) | A method of purifying gases containing nitrogen oxides and an apparatus for purifying gases in a steam generation boiler | |
| RU2543096C1 (en) | METHOD AND DEVICE FOR SELECTIVE CATALYTIC REDUCTION OF NOx IN POWER BOILER | |
| KR0158763B1 (en) | A method for optimizing the operating efficiency of a fossil-fired power generation system | |
| US5078973A (en) | Apparatus for treating flue gas | |
| EP0129167B1 (en) | Coal gasification composite power generating plant | |
| US4820492A (en) | Apparatus for denitration | |
| EP0309792B1 (en) | Exhaust boiler | |
| JPS6157927B2 (en) | ||
| EP0670175A1 (en) | Exhaust gas boiler | |
| JPH0773661B2 (en) | Injection type non-catalytic nitrogen oxide removal process control system | |
| US4880378A (en) | Combustion plant with a device for reducing nitrogen oxides in flue gases | |
| JP7420941B2 (en) | Arrangement and method for operating a steam boiler system | |
| JPS61250405A (en) | Steam-generating boiler | |
| US8042497B2 (en) | Steam generator arrangement | |
| Cobb et al. | Application of selective catalytic reduction (SCR) technology for NOx reduction from refinery combustion sources | |
| EP0189917B1 (en) | Apparatus for treating flue gas | |
| DE3332663A1 (en) | Process for optimising the reduction of NOx in flue gases from fossil fuel-fired furnaces | |
| JP2000065313A (en) | Boiler apparatus and boiler starting operation method | |
| JP3041263B2 (en) | Method of controlling nitrogen oxides in flue gas from pressurized fluidized-bed boiler | |
| Luke et al. | A: COM Environment | |
| JPH07112120A (en) | Denitrification device | |
| JPH0440057B2 (en) | ||
| Narita et al. | BABCOCK-HITACHI NOx REMOVAL PROCESS FOR FLUE GASES FROM COAL-FIRED BOILERS |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| 17P | Request for examination filed |
Effective date: 19960724 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT |
|
| 17Q | First examination report despatched |
Effective date: 19980512 |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB IT |
|
| REF | Corresponds to: |
Ref document number: 69604027 Country of ref document: DE Date of ref document: 19991007 |
|
| ITF | It: translation for a ep patent filed | ||
| ET | Fr: translation filed | ||
| PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
| 26N | No opposition filed | ||
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R082 Ref document number: 69604027 Country of ref document: DE Representative=s name: PATENTANWAELTE HENKEL, BREUER & PARTNER, DE Ref country code: DE Ref legal event code: R081 Ref document number: 69604027 Country of ref document: DE Owner name: MITSUBISHI HITACHI POWER SYSTEMS, LTD., YOKOHA, JP Free format text: FORMER OWNER: MITSUBISHI JUKOGYO K.K., TOKIO/TOKYO, JP |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 20 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20150624 Year of fee payment: 20 Ref country code: DE Payment date: 20150624 Year of fee payment: 20 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20150608 Year of fee payment: 20 |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: 732E Free format text: REGISTERED BETWEEN 20151022 AND 20151028 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: IT Payment date: 20150625 Year of fee payment: 20 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: TP Owner name: MITSUBISHI HITACHI POWER SYSTEMS, LTD., JP Effective date: 20151222 Ref country code: FR Ref legal event code: CD Owner name: MITSUBISHI HITACHI POWER SYSTEMS, LTD., JP Effective date: 20151222 Ref country code: FR Ref legal event code: CA Effective date: 20151222 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R071 Ref document number: 69604027 Country of ref document: DE |
|
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 Expiry date: 20160626 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20160626 |