Technical Field
[0001]
The present invention relates to a burner for highly
caking coal that is applied to a solid fuel gasifier or the
like of an integrated coal gasification combined cycle
facility, and to a gasifier.
Background Art
[0002]
Conventionally, so-called integrated coal gasification
combined cycle power plants (IGCC) have been developed and put
into practical use with the goal of improving the power
generation efficiency of coal-fired power plants. Such an
integrated coal gasification combined cycle power plant
(hereinafter, referred to as an "IGCC") includes a gas turbine
generator that uses coal gas obtained by gasifying coal as a
fuel, to operate and generate power, and a steam turbine
generator that uses the steam obtained by recovering heat from
high-temperature combustion exhaust gas discharged from the
gas turbine using an exhaust heat recovery boiler, to operate
and generate power.
[0003]
In such an IGCC, the fuel supply to the gasifier that
generates the coal gas is performed by transporting a solid
fuel that has been pulverized into particles to a burner by
using gas flow of nitrogen, carbon dioxide, air, or the like
as a carrier gas, and jetting the solid fuel from the burner
into the gasifier. On the other hand, a high-pressure
operation in which the internal pressure in the gasifier is
set high is performed, in view of the configuration of the
system and the reactions inside the gasifier.
In order to perform such a high-pressure operation, the
gasifier that is operated at a high pressure is formed as a
pressure vessel, and a burner that penetrates through the wall
surface of this pressure vessel houses a solid fuel
(pulverized coal, petroleum coke, or the like) and a gasifying
agent (air, oxygen, water steam, or the like) in the same
pipe.
[0004]
FIGS. 10A and 10B show a conventional structure in which
the burner section of a gasifier is enlarged. In the
structure, a burner for highly caking coal (hereinafter
referred to as a "burner") 12 is attached penetrating through
a surrounding wall (furnace wall) 11 of a gasifier 10 that is
formed as a pressure vessel. The burner 12 has a double pipe
structure in which a solid fuel channel 13 on the inner side
and a gasifying agent channel 14 on the outer side are
arranged concentrically.
The solid fuel channel 13 is connected via a fuel supply
line 16 with a high-pressure fuel supply unit 15 that supplies
a solid fuel that has been pulverized into particles. Also, a
carrier gas whose flow rate is controlled by a flow rate
control unit 17 is supplied to the high-pressure fuel supply
unit 15. Accordingly, the solid fuel channel 13 supplies the
solid fuel, which is adjusted to the desired supply rate by
the high-pressure fuel supply unit 15, into the gasifier 10,
using the carrier gas, which is adjusted to the desired flow
rate by the flow rate control unit 17. That is, the
particulate solid fuel is transported by the carrier gas flow,
and supplied into the gasifier 10.
[0005]
The gasifying agent channel 14 is connected with a
gasifying agent supply line 18 that supplies a gasifying
agent, and supplies the gasifying agent, which is adjusted to
the desired supply rate by a flow rate control unit (not
shown), into the gasifier 10.
Thus, by supplying the solid fuel, the carrier gas, and
the gasifying agent into the gasifier 10, the solid fuel that
has undergone a predetermined treatment in the gasifier 10 is
gasified, and supplied to a gas cleanup facility in a
subsequent step.
[0006]
As another conventional technology, in a pulverized raw
material gasification apparatus of the entrained flow-type
that uses a pulverized carbon raw material such as coal as a
gasification raw material, in addition to using a carrier gas,
such as nitrogen gas, for the gasification raw material and an
oxidizing agent such as oxygen or air, and gasifies the raw
material at a temperature of at least the melting point of the
ashes of the pulverized carbon raw material, it is known to
provide a gas spouting nozzle upstream of an area near an exit
portion where the carrier line of the gasification raw
material is supplied into the gasification apparatus, in order
to spout a gas such as nitrogen gas, carbon dioxide gas, or an
inert gas toward the exit portion of the carrier line, and
cause that gas to merge with the gasification raw material.
This gas spouting nozzle blows away slag or the like adhering
to the exit portion of the carrier line of the gasification
raw material, and is considered to be capable of constantly
maintaining a state where no matter is adhering to the burner
exit portion (for example, see Patent Citation 1).
[0007]
In addition, a technology has been disclosed by which an
auxiliary mixing nozzle that blows, as gas flow, compressed
air supplied from a part of a secondary fuel air or from the
outside of a wind box is provided in a pulverized solid fuel
combustion apparatus that burns a mixture of a solid fuel such
as pulverized coal and a gas such as air as a fuel, thereby
preventing the erosion of a fuel-air mixture nozzle and the
adhesion and deposition of the fuel (for example, see Patent
Citation 2).
Patent Citation 1: Japanese Examined Patent Application,
Publication No. Hei 08-003361 (see FIG. 1)
Patent Citation 2: The Publication of Japanese Patent No.
3790489
Disclosure of Invention
[0008]
According to the above-described conventional technology
shown in FIGS. 10A and 10B, the high-pressure operation of the
gasifier 10 for gasifying the solid fuel leads to a state
where the interparticle distance of the solid fuel transported
by gas flow is small. That is, the solid fuel transported by
gas flow through the solid fuel channel 13 has a very high
spatial filling fraction.
On the other hand, in the burner 12 including the solid
fuel channel 13 and the gasifying agent channel 14 arranged in
a concentric double pipe structure, the heat transfer
coefficient between the two channels 13 and 14 becomes high,
so that the amount of heat with which the gasifying agent at
the high temperature side heats the solid fuel at the low
temperature side is increased.
[0009]
For this reason, the particle temperature of the solid
fuel that is subject to heating by the gasifying agent is
increased, and the particles of the solid fuel having an
elevated temperature fuse and expand. At this time, when the
solid fuel is highly caking, there may be the problem that the
fused and expanded adjacent particles of the solid fuel
agglomerate, thereby causing incomplete combustion, or the
problem that the fused and expanded solid fuel adheres to the
internal surface of the solid fuel channel 13, thereby causing
blockage of the burner 12. Such problems occur not only with
burners that use solid fuels such as pulverized coal and
petroleum coke, but also with burners of the gasifiers that
use other highly caking solid fuels, including, for example,
oil residue and plastics.
[0010]
Thus, in a burner for highly caking coal used for a
gasifier for gasifying a highly caking solid fuel, there is a
need to solve the problems that could be caused by the
temperature increase of the solid fuel particles and the
resulting fusion and expansion thereof, due to heat transfer
in the burner, which includes a solid fuel channel and a
gasifying agent channel in a concentric double pipe structure.
The present invention was achieved in view of the
foregoing circumstances, and it is an object of the invention
to provide a burner for highly caking coal in which a solid
fuel channel and a gasifying agent channel are provided in a
double pipe structure, wherein the temperature increase of the
particles of a highly caking solid fuel due to heat transfer
in the burner and the resulting fusion and expansion of the
particles are prevented or suppressed, thereby enabling a
stable operation of the gasifier.
[0011]
The following solutions were used for the present
invention in order to solve the above-described problems.
A burner for highly caking coal according to the present
invention is a burner for highly caking coal in which a solid
fuel channel that is attached penetrating through a furnace
wall of a gasifier for gasifying a highly caking solid fuel
that has been pulverized into particles and that supplies the
solid fuel into the gasifier by gas flow transportation, and a
gasifying agent channel that supplies a gasifying agent into
the gasifier are provided in a double pipe structure, wherein
a blockage situation detection means that detects a blockage
situation of the solid fuel channel is provided, and a process
for reducing a temperature of the solid fuel is performed when
the blockage situation detection means detects a predetermined
blockage situation.
[0012]
With such a burner for highly caking coal, a blockage
situation detection means that detects a blockage situation of
the solid fuel channel is provided, and a process for reducing
the temperature of the solid fuel is performed when the
blockage situation detection means detects a predetermined
blockage situation. Accordingly, it is possible to decrease
the solid fuel temperature that may cause a channel blockage,
in accordance with the state of progress of the channel
blockage of the solid fuel channel, thereby preventing or
suppressing the fusion and the expansion due to a temperature
increase of the particles of the highly caking solid fuel.
[0013]
In the invention described above, it is preferable that
the temperature reduction process includes outputting a
control signal for increasing an amount of a carrier gas used
for the gas flow transportation. This reduces the retention
time of the solid fuel and the carrier gas in the solid fuel
channel, so that the amount of heat exchanged between the
solid fuel and the high-temperature gasifying agent can be
reduced.
[0014]
In the invention described above, it is preferable that
the temperature reduction process includes outputting a
control signal for decreasing a temperature of the gasifying
agent. This reduces the temperature of the gasifying agent on
the heating side, thereby decreasing the temperature
difference between the solid fuel and the carrier gas that
flow through the inside of the solid fuel channel.
Accordingly, it is possible to reduce the amount of heat
exchanged between a solid fuel and a high-temperature
gasifying agent.
[0015]
In the invention described above, it is preferable that
the temperature reduction process includes, in combination,
outputting a control signal for increasing an amount of a
carrier gas used for the gas flow transportation, and
outputting a control signal for decreasing a temperature of
the gasifying agent. This reduces the retention time of the
solid fuel and the carrier gas in the solid fuel channel, as
well as the temperature of the gasifying agent and the
temperature difference between the solid fuel and the carrier
gas that flow through the solid fuel channel, thereby reducing
the amount of heat exchanged between the solid fuel and the
high-temperature gasifying agent even more efficiently.
[0016]
In the invention described above, it is preferable that
the blockage situation detection means detects a differential
pressure between a burner inlet of the solid fuel channel and
a suitable place located downstream from the burner inlet, and
judges that a blockage situation is detected when a flow loss
coefficient converted from the differential pressure increases
to at least a predetermined value. This makes it possible to
reliably judge a channel blockage situation of the solid fuel
channel, based on a flow loss coefficient obtained by
converting the pressure of the gasifier and the differential
pressure that changes according to the flow rate of the solid
fuel and the flow rate of the carrier gas.
[0017]
In the invention described above, it is preferable that
the blockage situation detection means judges that a blockage
situation is detected when a flow loss coefficient converted
from a differential pressure ratio of a first differential
pressure detected between a burner inlet and a suitable place
located downstream from the burner inlet and a second
differential pressure measured in an arbitrary section set in
a fuel supply line connected to an upstream side of the solid
fuel channel increases to at least a predetermined value. This
makes it possible to reliably judge a channel blockage
situation of the solid fuel channel, based on a flow loss
coefficient obtained by the pressure of the gasification
channel and the differential pressure that is not affected by
the influence of the flow rate of the solid fuel and the flow
rate of the carrier gas.
[0018]
In the invention described above, it is preferable that
the temperature reduction process comprises an upper limit
monitoring means that detects an internal surface temperature
of the solid fuel channel, and monitors the internal surface
temperature so that the internal surface temperature does not
become greater than a preset temperature determined according
to a caking property of the solid fuel. This enables an
efficient operation at a maximum temperature at which the
problem of channel blockage does not occur.
[0019]
A gasifier according the present invention is a gasifier
in the form of a pressure vessel into which a solid fuel such
as particulate highly caking coal is supplied by gas flow
transportation, and that subjects the solid fuel to a
gasification treatment under a high-pressure environment
together with a gasifying agent, wherein the gasifier includes
the burner for highly caking coal according to any of claims 1
to 7.
[0020]
Such a gas furnace includes the above-described burner
for highly caking coal, and therefore can decrease the solid
fuel temperature that may cause a channel blockage, in
accordance with the state of progress of the channel blockage
of the solid fuel channel in the burner for highly caking
coal, thereby preventing or suppressing the fusion and the
expansion due to a temperature increase of the particles of
the highly caking solid fuel.
[0021]
With the present invention described above, in a burner
for highly caking coal used for a gasifier for gasifying a
highly caking solid fuel, it is possible to prevent or
suppress the fusion and expansion of the solid fuel particles
that could be caused by the temperature increase of the solid
fuel particles, due to heat transfer in the burner, which
includes a solid fuel channel and a gasifying agent channel in
a concentric double pipe structure. Accordingly, it is
possible to prevent the problem that fused and expanded
adjacent particles agglomerate due to the temperature increase
of the highly caking solid fuel, thereby causing incomplete
combustion, or the problem that those particles adhere to the
internal surface of the solid fuel channel, thereby causing
blockage. Accordingly, it is possible to operate the burner
for highly caking coal and the gasifier in a stable manner.
Furthermore, it is also possible to expand the range of
applications for highly caking solid fuels that can be used
for the burner for highly caking coal and the gasifier.
Brief Description of Drawings
[0022]
[FIG. 1] FIG. 1 is a configuration diagram of a relevant
part illustrating a first embodiment of a burner for highly
caking coal and a gasifier according to the present invention.
[FIG. 2] FIG. 2 is a block diagram showing the outline of
an integrated coal gasification combined cycle plant (IGCC).
[FIG. 3] FIG. 3 is a flowchart illustrating an example of
control for a blockage detection unit according to the first
embodiment.
[FIG. 4] FIG. 4 is a configuration diagram of a relevant
part illustrating a second embodiment of a burner for highly
caking coal and a gasifier according to the present invention.
[FIG. 5] FIG. 5 is a configuration diagram of a relevant
part illustrating a third embodiment of a burner for highly
caking coal and a gasifier according to the present invention.
[FIG. 6] FIG. 6 is a configuration diagram of a relevant
part illustrating a burner for highly caking coal and a
gasifier as a modification of the third embodiment shown in
FIG. 5.
[FIG. 7] FIG. 7 is a configuration diagram of a relevant
part illustrating a fourth embodiment of a burner for highly
caking coal and a gasifier according to the present invention.
[FIG. 8] FIG. 8 is a configuration diagram of a relevant
part illustrating a burner for highly caking coal and a
gasifier as a modification of the fourth embodiment shown in
FIG. 7.
[FIG. 9] FIG. 9 is a configuration diagram of a relevant
part illustrating a fifth embodiment of a burner for highly
caking coal and a gasifier according to the present invention.
[FIG. 10A] FIG. 10A is a configuration diagram
illustrating an example of a conventional burner for highly
caking coal and gasifier.
[FIG. 10B] FIG. 10B is a view taken along the arrows A-A
in FIG. 10A.
Explanation of Reference:
[0023]
10: Gasifier
11: Surrounding wall (Furnace wall)
12: Burner for highly caking coal (Burner)
13: Solid fuel channel
14: Gasifying agent channel
20, 20A to 20F: Blockage detection unit
30: Temperature control unit
40: Temperature sensor
Best Mode for Carrying Out the Invention
[0024]
Hereinafter, one embodiment of a burner for highly caking
coal and a gasifier according to the present invention will be
described based on the drawings.
FIG. 2 is a block diagram showing the outline of an
integrated coal gasification combined cycle (IGCC). This IGCC
is a combined cycle power generation facility that generates
power using coal gas obtained by gasifying coal (a solid fuel)
as a fuel. That is, the IGCC includes, as its main components,
a solid fuel dry grinding unit 1 that dries and grinds a solid
fuel such as coal into a particulate solid fuel, a highpressure
fuel supply unit 2 that supplies the particulate
solid fuel by gas flow using a carrier gas, a gasifier
facility 3 that receives the supply of the solid fuel
transported by gas flow into the gasifier and the gasifying
agent, and gasifies the solid fuel to obtain a gasified coal
gas, a gas cleanup facility 4 that removes impurities and the
like contained in the coal gas produced at the gasifier
facility 3, thereby purifying the coal gas, and a combined
cycle power generation facility 5 constituted by a gas turbine
generator and a steam turbine generator.
[0025]
The gas turbine generator is a generator that operates a
gas turbine by using purified coal gas as a fuel, and
generates power by being driven by the shaft output of the gas
turbine.
The steam turbine generator is a generator that generates
power by being driven by the shaft output of the steam turbine
operated using steam energy produced by recovering heat from
the combustion exhaust gas by introducing a high-temperature
combustion exhaust gas into an exhaust heat recovery boiler
discharged from the gas turbine of the gas turbine generator.
[0026]
First Embodiment
As shown in FIG. 1, the gasifier facility 3 of the IGCC
described above is provided with a gasifier 10 in the form of
a pressure vessel. A burner 12 for highly caking coal
(hereinafter referred to as a "burner") is attached to the
gasifier 10 such that it penetrates through a surrounding wall
11, which is a furnace wall constituting the pressure vessel.
The burner 12 has a concentric double pipe structure
including a solid fuel channel 13 that is disposed on the
inner side, and a gasifying agent channel 14 that is disposed
on the outside.
[0027]
The solid fuel channel 13 is a fuel supply channel that
supplies a highly caking solid fuel that has been pulverized
into particles into the gasifier 10. The solid fuel channel 13
is connected with a high-pressure fuel supply unit 15 via a
fuel supply line 16.
The high-pressure fuel supply unit 15 is an apparatus for
receiving supply of the solid fuel pulverized into particles,
and supplying the desired amount of the solid fuel to the
gasifier 10 by gas flow transportation using a carrier gas.
The carrier gas is supplied to the high pressure fuel supply
unit 15 via the flow rate control unit 17 and a carrier gas
supply line 19. Carrier gases that can be used for the gas
flow transportation in this case include nitrogen, carbon
dioxide, air, and the like.
[0028]
The gasifying agent channel 14 is connected with a
gasifying agent source (not shown) via a gasifying agent
supply line 18. The gasifying agent channel 14 supplies a
high-temperature gasifying agent that is adjusted at the
desired flow rate into the gasifier 10. Gasifying agents that
can be used in this case include air, oxygen, steam, and the
like.
Thus, in the burner 12, the solid fuel channel 13 that is
attached penetrating through the surrounding wall (furnace
wall) 11 of the gasifier 10 for gasifying a highly caking
solid fuel that has been pulverized into particles and
supplying the solid fuel into the gasifier 10 by gas flow
transportation, and the gasifying agent channel 14 that
supplies a gasifying agent into the gasifier are arranged in a
double pipe structure.
[0029]
Moreover, the burner 12 described above includes a
blockage detection unit 20 that is provided as a blockage
situation detection means to detect a blockage situation of
the solid fuel channel 13. The blockage detection unit 20
detects a differential pressure Pa between the pressure at the
burner inlet of the solid fuel channel 13 and the internal
pressure of the gasifier 10 as a suitable place located
downstream from the burner inlet. When a flow loss coefficient
converted from that differential pressure Pa increases to at
least a predetermined value, the blockage detection unit 20
judges that a blockage situation of the solid fuel channel 13
has been detected. In the illustrated example, the burner
inlet pressure P1 of the solid fuel channel 13 and the
internal pressure P2 of the gasifier 10 are detected, and the
differential pressure Pa is calculated from the two pressures
P1 and P2. It should be noted that for the differential
pressure Pa calculated here, a burner outlet pressure P3 may
be used in place of the internal pressure P2 of the gasifier
10.
[0030]
When the blockage detection unit 20 detects a
predetermined blockage situation, a process for reducing the
temperature of the solid fuel is carried out. This temperature
reduction process reduces the retention time of the solid fuel
and the carrier gas in the solid fuel channel 13 by outputting
a control signal for increasing the amount of the carrier gas
used for the gas flow transportation. That is, by increasing
the flow velocity of the solid fuel flowing through the inside
of the solid fuel channel 13 in the burner 12 having the
concentric double pipe structure, the time is shortened during
which heat exchange is carried out between the solid fuel on
the low temperature side and the gasifying agent on the high
temperature side. Accordingly, the amount of heat exchanged
between the solid fuel and the gasifying agent is reduced. As
a result, it is possible to prevent the solid fuel from being
heated by the high-temperature gasifying agent flowing around
the solid fuel, thereby making it possible to prevent or
suppress the temperature of the solid fuel particles from
increasing to a temperature at which those particles fuse and
expand.
[0031]
Hereinafter, an example of a control performed within the
blockage detection unit 20 will be described based on the flow
chart shown in FIG. 3.
After the control starts at the first step S1, the
procedure moves to the subsequent step S2, at which the
judgment "Is the operation to be continued?" is carried out.
If the result is "YES" and the operation of the gasifier 10 is
continued, the procedure moves to the subsequent step S3, at
which a differential pressure Pa is detected. The differential
pressure Pa in this case is obtained by detecting the burner
inlet pressure P1 of the solid fuel channel 13 and the
internal pressure P2 of the gasifier 10. It should be noted
that if the result in step S2 is "NO" and the operation of the
gasifier 10 will not be continued, the procedure moves to the
subsequent step S8, at which the control ends.
[0032]
The differential pressure Pa detected at step S3 is
converted into a flow loss coefficient λ in the subsequent
step S4. That is, in the case of transporting the solid fuel
particles by gas flow, the differential pressure Pa changes
depending on the internal pressure of the gasifier 10, the
flow rate of the solid fuel, and the flow rate of a carrier
gas. Accordingly, in order to reliably judge the channel
blockage situation of the solid fuel channel, it is desirable
to carry out a judgment based on a flow loss coefficient λ
obtained by converting the differential pressure Pa. The flow
loss coefficient λ is a value used for a known expression for
determining the pressure loss of a solid-gas two-phase flow.
That is, since the differential pressure Pa described above is
a value equivalent to a pressure loss, it is possible to
calculate an actual flow loss coefficient λ in the burner 12
from the known expression for determining this pressure loss
and a detected value of the differential pressure Pa.
[0033]
In the subsequent step S5, the flow loss coefficient λ
calculated at step S4 is subjected to the judgment "Does the
flow loss coefficient have at least a predetermined value?".
If this result is YES and the flow loss coefficient λ has at
least a predetermined value, it can be judged that a larger
pressure loss of at least a predetermined value has occurred
in a solid-gas two-phase flow of the solid fuel and the
carrier gas that flow through the solid fuel channel 13. That
is, it can be judged that a situation has occurred where the
pressure loss of the solid-gas two-phase flow increases,
including for example, a situation where the solid fuel
adheres to the internal surface of the solid fuel channel 13,
thus reducing the channel cross sectional area. Accordingly,
the procedure moves to the subsequent step S6, at which an
instruction to increase the carrier gas flow rate is output.
It should be noted that if the result at step S5 is "NO" and
the flow loss coefficient λ has a value smaller than a
predetermined value, then it is judged that there is no
problem in the current operation, and the procedure moves to
step S2 described above, and repeats the same control flow.
[0034]
If an instruction to increase the carrier gas flow rate
is output at step S6, the procedure moves to the subsequent
step S7, at which the carrier gas flow rate is increased. That
is, when the flow rate control unit 17 receives the
instruction to increase the carrier gas flow rate, an
operation of increasing the flow rate of the carrier gas
supplied to the high-pressure fuel unit 17 is performed.
As a result, the amount of the carrier gas for the gas
flow transportation in the solid fuel channel 13 increases,
and the flow velocities of the solid fuel and the carrier gas
that flow through the inside of the solid fuel channel 13
increase, so that the time during which the solid fuel is
retained in the channel is reduced. That is, the time during
which the solid fuel on the low temperature side flowing
through the inside of the solid fuel channel 13 receives heat
from the high-temperature gasifying agent flowing around the
solid fuel is shortened, so that it is possible to prevent or
suppress a temperature increase of the solid fuel.
[0035]
After the control for increasing the amount of the
carrier gas is performed in this manner, the procedure returns
to step S2, and repeats the same control flow.
When a blockage situation of the solid fuel channel 13 is
detected by this control performed by the blockage detection
unit 20, the flow rate of the carrier gas is increased as the
temperature reduction process for the solid fuel, and thus the
flow velocity is increased. Accordingly, it is possible to
reduce a temperature increase of the solid fuel that could
cause a channel blockage, in accordance with the state of
progress of the channel blockage of the solid fuel channel 13.
Therefore, the particles of the highly caking solid fuel can
be prevented or suppressed from increasing to a high
temperature greater than a prescribed temperature that varies
depending on the type of the solid fuel, so that the adhesion
to the wall surface or the agglomeration due to their fusion
and expansion can also be prevented or suppressed.
[0036]
Second Embodiment
A second embodiment of the present invention will be
described based on FIG. 4. It should be noted that the same
portions in FIG. 4 as in the above-described embodiment are
denoted by the same reference numerals, and a detailed
description thereof has been omitted.
In this embodiment, when a blockage situation is
detected, a different temperature reduction process is
performed by a blockage detection unit 20A. That is, instead
of increasing the amount of the carrier gas in the abovedescribed
embodiment, a temperature reduction process in which
a control signal for decreasing the temperature of the
gasifying agent is output is performed.
[0037]
Hereinafter, the temperature reduction control by which
the temperature of the gasifying agent is decreased will be
described specifically. In order to enable this temperature
reduction control, a temperature control unit 30 is provided
in the gasifying agent supply line 18.
The temperature control unit 30 has the function of
receiving an instruction to decrease the temperature of the
gasifying agent that is output from the blockage detection
unit 20A, and controlling the final temperature of the
gasifying agent that is supplied to the gasifying agent
channel 14 of the burner 12, for example, by adjusting the
mixing ratio of gasifying agents having different
temperatures.
[0038]
When a blockage situation of the solid fuel channel 13 is
detected in the same manner as in the above-described
embodiment, by performing such controls using the blockage
detection unit 20A and the temperature control unit 30, the
temperature of the gasifying agent is decreased as the
temperature reduction process for the solid fuel. Accordingly,
it is possible to reduce the temperature increase of the solid
fuel that could cause a channel blockage, in accordance with
the state of progress of the channel blockage of the solid
fuel channel 13. Therefore, the particles of the highly caking
solid fuel can be prevented or suppressed from increasing to a
high temperature greater than a prescribed temperature that
varies depending on the type of the solid fuel, so that the
adhesion to the wall surface or the agglomeration due to their
fusion and expansion can also be prevented or suppressed.
[0039]
Third Embodiment
A third embodiment of the present invention will be
described based on FIG. 5. It should be noted that the same
portions in FIG. 5 as in the above-described embodiments are
denoted by the same reference numerals, and a detailed
description thereof has been omitted.
In this embodiment, a different blockage situation
detection means that detects a blockage situation is used.
That is, in place of a flow loss coefficient λ converted from
a differential pressure Pa in the above-described embodiments,
a flow loss coefficient λ'' converted based on a differential
pressure ratio is used as a judgment criterion of a channel
blockage situation.
[0040]
More specifically, a blockage detection unit 20B serving
as a blockage situation detection means in this embodiment
judges that a blockage situation has been detected when a flow
loss coefficient λ'' converted from the differential pressure
ratio of a first differential pressure Pa detected between the
pressure P1 at the burner inlet and the internal pressure P2
of the gasifier 10 located downstream from the burner inlet,
and a second differential pressure Pb measured in an arbitrary
section set in the fuel supply line 16 connected to the
upstream side of the solid fuel channel 13 has increased to at
least a predetermined value. In the illustrated example, two
pressures P4 and P5 are detected in two fixed measurement
positions set in suitable places of the fuel supply line 16,
and a differential pressure Pb generated between the two
pressures P4 and P5 is the second differential pressure. That
is, the second differential pressure Pb approximately matches
the pressure loss that has occurred in a solid-gas two-phase
flow that has flown a predetermined channel length set in the
fuel supply line 16.
[0041]
Accordingly, the differential pressure ratio of the first
differential pressure Pa and the second differential pressure
Pb is a value that will not be affected by the influence of
the pressure of the gasifier 10, the flow rate of the solid
fuel and the flow rate of the carrier gas, so that it is
possible to reliably judge the channel blockage situation of
the solid fuel channel 13, based on the flow loss coefficient
λ'' obtained by this differential pressure ratio. That is, by
using, as the judgment criterion, whether or not the flow loss
coefficient λ'' has at least a predetermined value, and judging
the occurrence of a predetermined blockage situation when the
flow loss coefficient λ'' has at least a predetermined value,
the channel blockage situation of the solid fuel channel 13
can be judged even more reliably.
[0042]
A control for increasing the flow rate of the carrier gas
is performed in the embodiment shown in FIG. 5 as the
temperature reduction process at the time of detecting a
predetermined blockage situation. However, when a
predetermined blockage situation is detected, it is also
possible to decrease the temperature of the gasifying agent as
the temperature reduction process performed by a blockage
detection unit 20C, as in a modification shown in FIG. 6.
[0043]
Fourth Embodiment
A fourth embodiment of the present invention will be
described based on FIG. 7. It should be noted that the same
portions in FIG. 7 as in the above-described embodiments are
denoted by the same reference numerals, and a detailed
description thereof has been omitted.
In this embodiment, when a blockage situation of the
solid fuel channel 13 is detected, a temperature reduction
process carried out by a blockage detection unit 20D is
performed that includes, in combination, outputting a control
signal for increasing the amount of the carrier gas used for
gas flow transportation, and outputting a control signal for
decreasing the temperature of the gasifying agent. That is,
the amount of heat exchanged between the solid fuel and the
high-temperature gasifying agent can be reduced even more
efficiently by reducing the retention time of the solid fuel
and the carrier gas in the solid fuel channel 13 by increasing
the flow rate of the carrier gas, while reducing the
temperature of the gasifying agent as well as the temperature
difference between the solid fuel and the carrier gas that
flow through the inside of the solid fuel channel 13.
[0044]
A blockage detection unit 20E of a modification as shown
in FIG. 8 uses a flow loss coefficient λ'' converted based on a
differential pressure ratio as a judgment criterion for
detecting a blockage situation of the solid fuel channel 13,
in place of the flow loss coefficient λ converted from a
differential pressure Pa. Therefore, with the combination of a
reduction in the retention time of the solid fuel and the
carrier gas in the solid fuel channel 13 by increasing the
flow rate of the carrier gas, and a reduction in the
temperature of the gasifying agent and in the temperature
difference between the solid fuel and the carrier gas that
flow through the inside of the solid fuel channel 13, the
amount of heat exchanged between the solid fuel and the hightemperature
gasifying agent can be reduced even more
efficiently. Moreover, it is possible to judge a blockage
situation of the solid fuel channel 13 even more reliably,
using, as a judgment criterion, whether or not the flow loss
coefficient λ'' has at least a predetermined value.
[0045]
Fifth Embodiment
A fifth embodiment of the present invention will be
described based on FIG. 9. It should be noted that the same
portions in FIG. 9 as in the above-described embodiments are
denoted by the same reference numerals, and a detailed
description thereof has been omitted.
A blockage detection unit 20F of this embodiment is
provided with a temperature sensor 40 that detects an internal
surface temperature T of the solid fuel channel 13 and serves
as an upper limit monitoring means that monitors the internal
surface temperature T so that it does not become greater than
a preset temperature determined according to the caking
property of the solid fuel, at the time of performing a
temperature reduction process. Preferably, the temperature
sensor 40 detects the internal surface temperature of the
solid fuel channel 13 by being installed near the exit where
the temperature is highest, and the internal surface
temperature T detected with the sensor 40 is input to the
blockage detection unit 20F.
[0046]
Meanwhile, measured values for the melting temperature,
the flow temperature, the solidification temperature and the
like representing the caking property of the solid fuel that
is used are input in advance to the blockage detection unit
20F. In the blockage detection unit 20F, an upper limit preset
temperature determined according to the caking property of the
solid fuel that is actually used is decided based on these
input values.
Therefore, when a temperature reduction process is
performed that includes increasing the amount of the carrier
gas or decreasing the temperature of the gasifying agent, or
that includes, in combination, increasing the amount of the
carrier gas and decreasing the temperature of the gasifying
agent so that an actual internal surface temperature T does
not become greater than the upper limit preset temperature, it
is possible to realize an efficient operation at a maximum
temperature at which the problem of channel blockage does not
occur. That is, at the time of gasifying the solid fuel, by
performing the operation while monitoring the internal surface
temperature T so that it does not become greater than the
upper limit preset temperature at the time of gasifying the
solid fuel, it is possible to realize both prevention of
blockage of the burner 12 due to fusion and expansion of the
solid fuel, and good operation efficiency.
[0047]
Furthermore, by also performing a temperature reduction
process using the differential pressure ratio of the
differential pressures Pa and Pb or the differential pressure
Pa, it is possible to avoid, for example, the possibility that
an excessively low preset temperature causes a reduction in
the operation efficiency of the gasifier 10, or the
possibility that an excessively high present temperature
causes blockage of the burner, even if there are variations in
the caking properties of solid fuels.
[0048]
With the burner 12 for highly caking coal and the
gasifier 10 of the present invention, the burner for highly
caking coal 12 used for the gasifier 10 for gasifying a highly
caking solid fuel can prevent or suppress the fusion and
expansion of the solid fuel particles that could be caused by
a temperature increase of the solid fuel particles, due to
heat transfer in the burner, which includes the solid fuel
channel 13 and the gasifying agent channel 14 in a concentric
double pipe structure. Therefore, it is possible to prevent
the problem that fused and expanded adjacent particles
agglomerate due to the temperature increase of the highly
caking solid fuel, thereby causing incomplete combustion, or
the problem that those particles adhere to the internal
surface of the solid fuel channel 13, thereby causing blockage
of the burner. Accordingly, it is possible to operate the
burner 12 for highly caking coal and the gasifier 10 in a
stable manner. Furthermore, it is also possible to expand the
range of applications for highly caking solid fuels that can
be used for the burner 12 for highly caking coal and the
gasifier 10.
[0049]
The highly caking solid fuel has been described as a coal
in the above-described embodiments, but the highly caking
solid fuel is not limited to pulverized coal, petroleum coke
and the like, and the present invention is also applicable to
burners of gasifiers that use other highly caking solid fuels,
including, for example, oil residue and plastics.
It should be appreciated that the present invention is
not limited to the embodiments described above, and can be
suitably changed without departing from the gist of the
present invention.
CLAIMS
1. A burner for highly caking coal in which a solid fuel
channel that is attached penetrating through a furnace wall of
a gasifier for gasifying a highly caking solid fuel that has
been pulverized into particles and that supplies the solid
fuel into the gasifier by gas flow transportation, and a
gasifying agent channel that supplies a gasifying agent into
the gasifier are provided in a double pipe structure,
wherein a blockage situation detection means that detects
a blockage situation of the solid fuel channel is provided,
and a process for reducing a temperature of the solid fuel is
performed when the blockage situation detection means detects
a predetermined blockage situation.
2. The burner for highly caking coal according to claim 1,
wherein the temperature reduction process comprises outputting
a control signal for increasing an amount of a carrier gas
used for the gas flow transportation.
3. The burner for highly caking coal according to claim 1,
wherein the temperature reduction process comprises outputting
a control signal for decreasing a temperature of the gasifying
agent.
4. The burner for highly caking coal according to claim 1,
wherein the temperature reduction process comprises, in
combination, outputting a control signal for increasing an
amount of a carrier gas used for the gas flow transportation,
and outputting a control signal for decreasing a temperature
of the gasifying agent.
5. The burner for highly caking coal according to any of
claims 1 to 4, wherein the blockage situation detection means
detects a differential pressure between a burner inlet of the
solid fuel channel and a suitable place located downstream
from the burner inlet, and judges that a blockage situation is
detected when a flow loss coefficient converted from the
differential pressure increases to at least a predetermined
value.
6. The burner for highly caking coal according to any of
claims 1 to 4, wherein the blockage situation detection means
judges that a blockage when a flow loss coefficient converted
from a differential pressure ratio of a first differential
pressure detected between a burner inlet and a suitable place
located downstream from the burner inlet and a second
differential pressure measured in an arbitrary section set in
a fuel supply line connected to an upstream side of the solid
fuel channel increases to at least a predetermined value.
7. The burner for highly caking coal according to any of
claims 1 to 6, wherein the temperature reduction process
comprises an upper limit monitoring means that detects an
internal surface temperature of the solid fuel channel, and
monitors the internal surface temperature so that the internal
surface temperature does not become greater than a preset
temperature determined according to a caking property of the
solid fuel.
8. A gasifier into which a solid fuel such as particulate
highly caking coal is supplied by gas flow transportation, and
that subjects the solid fuel to a gasification treatment under
a high-pressure environment together with a gasifying agent,
wherein the gasifier comprises the burner for highly caking
coal according to any of claims 1 to 7.