U.S. patent application number 14/892151 was filed with the patent office on 2016-05-05 for solid fuel manufacturing method and manufacturing device.
This patent application is currently assigned to KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.). The applicant listed for this patent is KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.). Invention is credited to Shigeru KINOSHITA, Yoichi TAKAHASHI.
Application Number | 20160122675 14/892151 |
Document ID | / |
Family ID | 52104335 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160122675 |
Kind Code |
A1 |
KINOSHITA; Shigeru ; et
al. |
May 5, 2016 |
SOLID FUEL MANUFACTURING METHOD AND MANUFACTURING DEVICE
Abstract
A method and device manufacturing solid fuel, the method
includes: mixing porous coal with a mixture oil containing solvent
oil and heavy oil, to obtain material slurry; heating the material
slurry to promote dehydration of porous coal and impregnating the
mixture oil into pores of porous coal, to obtain dehydrated slurry;
separating upgraded porous coal and the mixture oil from the
dehydrated slurry; drying the upgraded porous coal by heating and
conveying it while supplying carrier gas; setting a target value of
the circulation amount of carrier gas and a target value of the
pressure of carrier gas at the drying; calculating control outputs,
based on deviations between the target values and measured values
corresponding respectively thereto; and adjusting the supply amount
of carrier gas, based on a smaller value between the control
outputs obtained.
Inventors: |
KINOSHITA; Shigeru;
(Takasago-shi, JP) ; TAKAHASHI; Yoichi;
(Takasago-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) |
Kobe-shi, Hyogo |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA KOBE SEIKO SHO
(KOBE STEEL, LTD.)
Kobe-shi, Hyogo
JP
|
Family ID: |
52104335 |
Appl. No.: |
14/892151 |
Filed: |
April 2, 2014 |
PCT Filed: |
April 2, 2014 |
PCT NO: |
PCT/JP2014/059767 |
371 Date: |
November 18, 2015 |
Current U.S.
Class: |
44/603 ;
44/629 |
Current CPC
Class: |
C10L 9/08 20130101; F26B
21/04 20130101; C10L 9/02 20130101; C10L 2290/06 20130101; C10L
2290/08 20130101; F26B 21/08 20130101; C10L 9/10 20130101; F26B
11/0477 20130101; C10L 2290/58 20130101; C10L 2290/24 20130101;
F26B 23/02 20130101 |
International
Class: |
C10L 9/10 20060101
C10L009/10; C10L 9/08 20060101 C10L009/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 2013 |
JP |
2013-128778 |
Claims
1: A method of manufacturing solid fuel comprising: mixing porous
coal with a mixture oil containing solvent oil and heavy oil, to
obtain material slurry; heating the material slurry to promote
dehydration of porous coal and impregnating the mixture oil into
pores of porous coal, to obtain dehydrated slurry; separating
upgraded porous coal and the mixture oil from the dehydrated
slurry; drying the upgraded porous coal by heating and conveying it
while supplying carrier gas; setting a target value of the
circulation amount of carrier gas and a target value of the
pressure of carrier gas at the drying; calculating control outputs,
based on deviations between the target values and measured values
corresponding respectively thereto; and adjusting the supply amount
of carrier gas, based on a smaller value between the control
outputs obtained.
2: The method of manufacturing solid fuel according to claim 1,
wherein the target values are each decided based on the supply
amount of upgraded porous coal to be dried at the drying and on the
amount of oil contained in upgraded porous coal subjected to the
drying.
3: The method of manufacturing solid fuel according to claim 2,
wherein the target values are each decided such that the pressure
of carrier gas at the drying lies within a preset range.
4: A device for manufacturing solid fuel comprising: a mixing
vessel that mixes porous coal with a mixture oil containing solvent
oil and heavy oil, to obtain material slurry; an evaporator that
heats the material slurry to promote dehydration of porous coal and
that impregnates the mixture oil into pores of porous coal, to
obtain dehydrated slurry; a centrifuge that separates upgraded
porous coal and the mixture oil from the dehydrated slurry; a dryer
that dries the upgraded porous coal by heating and conveying it
while supplying carrier gas; and a controller that sets a target
value of the circulation amount of carrier gas and a target value
of the pressure of carrier gas in the dryer, that calculates
control outputs, based on deviations between the target values and
measured values corresponding respectively thereto, and that
adjusts the supply amount of carrier gas, based on a smaller value
between the control outputs obtained.
5: The device for manufacturing solid fuel according to claim 4,
wherein the controller decides the target values, each based on the
supply amount of upgraded porous coal to be dried in the dryer and
on the amount of oil contained in upgraded porous coal leaving the
dryer.
6: The device for manufacturing solid fuel according to claim 5,
wherein the controller decides each of the target values such that
the pressure of carrier gas at a drying operation in the dryer lies
within a preset range.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of and a device
for manufacturing solid fuel using porous coal as a starting
material. More particularly, the present invention relates to a
method of and a device for manufacturing solid fuel, characterized
by a stable operation of a drying step in which separated upgraded
porous coal is heated and conveyed to be dried while being supplied
with a carrier gas.
BACKGROUND ART
[0002] A conventional method of manufacturing solid fuel using
porous coal as a starting material is for example a method
described in Patent Document 1. In the method, porous coal
(material coal) is first crushed at a crushing step, and then mixed
with mixture oil containing heavy oil and solvent oil at a mixing
step to obtain material slurry. After preheating, the material
slurry is heated to dehydrate porous coal and impregnate its pores
with mixture oil at an evaporation step, to obtain dehydrated
slurry. The dehydrated slurry is separated into upgraded porous
coal and mixture oil at a solid-liquid separation step and
thereafter only the upgraded porous coal is dried at a drying step.
At the drying step, the upgraded porous coal is conveyed and heated
within a heating type rotary dryer so that it is dried by allowing
carrier gas to flow. The dried upgraded porous coal is then cooled
and molded to obtain solid fuel. On the other hand, mixture oil
recovered at the solid-liquid separation step and the drying step
is refluxed to the mixing step for reuse. Carrier gas recovered at
the drying step is again refluxed into the dryer for reuse.
[0003] However, the conveyance amount of porous coal may vary due
to a variation in the operation status at each step. For this
reason, if the conveyance amount of upgraded porous coal rapidly
increases at the drying step, the amount of evaporated oil may
increase to raise the inner pressure. This may impair the sealing
properties (sealability), with the result that gas may leak out.
Ordinarily, although the main component of carrier gas is nitrogen,
carrier gas contains solid in addition to solvent oil and moisture,
so that there may occur increased running cost due to solvent oil
loss and adverse effects on the ambient environment due to
scattering of dust and generation of foreign odor.
[0004] On the other hand, if the conveyance amount of upgraded
porous coal rapidly decreases at the drying step, the amount of
evaporated oil may reduce to lower the inner pressure to a negative
pressure. In consequence, the ambient atmosphere enters the inside
and the internal oxygen concentration rises, with the result that
the stability of high-temperature upgraded porous coal may be
impaired.
PRIOR ART DOCUMENT
Patent Document
[0005] Patent Document 1: JP-A-7-233383
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0006] Thus, an object of the present invention is to enable a
drying step to be executed in a stable state regardless of the
increase or decrease in the conveyance amount of porous coal.
Means for Solving Problem
[0007] The present invention provides, as means for solving the
problem, a method of manufacturing solid fuel including:
[0008] a mixing step of mixing porous coal with a mixture oil
containing solvent oil and heavy oil, to obtain material
slurry;
[0009] an evaporation step of heating the material slurry to
promote dehydration of porous coal and impregnating the mixture oil
into pores of porous coal, to obtain dehydrated slurry;
[0010] a solid-liquid separation step of separating upgraded porous
coal and the mixture oil from the dehydrated slurry; and
[0011] a drying step of drying the upgraded porous coal by heating
and conveying it while supplying carrier gas, wherein
[0012] the method includes:
[0013] setting a target value of the circulation amount of carrier
gas and a target value of the pressure of carrier gas at the drying
step;
[0014] calculating control outputs, based on deviations between the
target values and measured values corresponding respectively
thereto; and
[0015] adjusting the supply amount of carrier gas, based on a
smaller value between the control outputs obtained.
[0016] According to this, the supply amount of carrier gas is
adjusted based on a smaller one between control outputs that are
calculated based respectively on the circulation amount and the
pressure of carrier gas, so that carrier gas pressure at the drying
step can be stabilized without significant changes.
[0017] Preferably, the target values are each decided based on the
supply amount of upgraded porous coal to be dried at the drying
step and on the amount of oil contained in upgraded porous coal
subjected to the drying step.
[0018] Preferably, the target values are each decided such that the
pressure of carrier gas at the drying step lies within a preset
range.
[0019] The present invention provides, as means for solving the
problem, a device for manufacturing solid fuel including:
[0020] a mixing vessel that mixes porous coal with a mixture oil
containing solvent oil and heavy oil, to obtain material
slurry;
[0021] an evaporator that heats the material slurry to promote
dehydration of porous coal and that impregnates the mixture oil
into pores of porous coal, to obtain dehydrated slurry;
[0022] a centrifuge that separates upgraded porous coal and the
mixture oil from the dehydrated slurry;
[0023] a dryer that dries the upgraded porous coal by heating and
conveying it while supplying carrier gas; and
[0024] a control unit that sets a target value of the circulation
amount of carrier gas and a target value of the pressure of carrier
gas in the dryer, that calculates control outputs, based on
deviations between the target values and measured values
corresponding respectively thereto, and that adjusts the supply
amount of carrier gas, based on a smaller value between the control
outputs obtained.
[0025] Preferably, the control unit decides the target values, each
based on the supply amount of upgraded porous coal to be dried in
the dryer and on the amount of oil contained in upgraded porous
coal leaving the dryer.
[0026] Preferably, the control unit decides each of the target
values such that the pressure of carrier gas at a drying step lies
within a preset range.
Effect of the Invention
[0027] According to the present invention, the supply amount of
carrier gas is adjusted based on a smaller one between control
outputs that are calculated based respectively on the circulation
amount and the pressure of carrier gas. For this reason, the
circulation amount and the pressure of carrier gas can rapidly
reach a stable state, thereby contributing to the stable
operability at the drying step.
BRIEF DESCRIPTION OF DRAWINGS
[0028] FIG. 1 is a schematic diagram showing part of an upgraded
brown coal manufacturing device according to an embodiment.
MODE FOR CARRYING OUT THE INVENTION
[0029] An embodiment according to the present invention will now be
described with reference to the accompanying drawing.
[0030] FIG. 1 schematically shows part of an upgraded brown coal
manufacturing device (an example of a solid fuel manufacturing
device) according to the embodiment. Although not shown, the
upgraded brown coal manufacturing device executes a mixing step in
a mixing vessel, executes an evaporation step in an evaporator, and
executes a solid-liquid separation step in a decanter centrifuge.
The upgraded brown coal manufacturing device executes a drying step
in a dryer 1, to obtain upgraded brown coal.
[0031] In the dryer 1, upgraded porous coal is heated and conveyed
to be dried while being supplied with a carrier gas. Nitrogen
(N.sub.2) is used herein as carrier gas to prevent upgraded porous
coal from firing. Upgraded porous coal supplied into the dryer 1 is
assumed to contain 30-40% of oil.
[0032] The dryer 1 used is of an indirect heating type having a
heater not shown in which the temperature of the internal carrier
gas is controlled to approximately 200.degree. C. Upgraded porous
coal is conveyed by a screw conveyor within the dryer 1. The screw
conveyor has a tubular rotary shaft whose outer peripheral surface
is formed with a plurality of small-diameter apertures. Carrier gas
can newly be supplied via the rotary shaft into the dryer 1.
[0033] A circulation path 2 is connected to the dryer 1, for
recovering carrier gas to again supply it into the dryer 1. Midway
along the circulation path 2 there are arranged, in the mentioned
order from the outlet side of the dryer 1, a dust collector 3, a
spray tower 4, a blower 5, a flow rate detection sensor 6, a first
flow rate regulating valve 7, and a first pressure detection sensor
8. An exhaust pipe 9 is connected to a piping extending from the
spray tower 4 to the blower 5 and is disposed with a second flow
rate regulating valve 10. The pressure in the middle of a piping
connecting the dust collector 3 and the spray tower 4 is detected
by a second pressure detection sensor 11.
[0034] A detection signal from the flow rate detection sensor 6 is
input to a flow indication controller (FIC) 12. A detection signal
from the first pressure detection sensor 8 is input to a first
pressure indication controller (PIC) 13. The FIC 12 and the PIC 13
calculate control output values from Math. 1 as will be described
later. The control output values calculated by the FIC 12 and the
PIC 13 are compared by a low select circuit (LS circuit) 14 so that
the opening of the first flow rate regulating valve 7 is adjusted
based on a lower one. In this case, the opening of the first flow
rate regulating valve 7 is adjusted so that carrier gas pressure in
the circulation path 2 is kept within the predetermined range
(e.g., 1-2 kPa. Note that this value varies depending on the
sealing designs and operation conditions for a conveyer, the dryer
1, etc.). A detection signal from the second pressure detection
sensor 11 is input to a second PIC 215. Based on this input signal,
the second PIC 15 regulates the opening of the second flow rate
regulating valve 10 in a manner as described later, to thereby
restrain the pressure in the circulation path 2 from rising.
[0035] The dust collector 3 serves to collect upgraded porous coal
dust contained in carrier gas discharged from the dryer 1.
[0036] Upgraded brown coal (UBC) is discharged from the dryer 1 or
the dust collector 3.
[0037] The spray tower 4 serves to condense and separate mixture
oil from carrier gas passing through the dust collector 3.
[0038] The blower 5 serves to form a carrier gas flow from the
circulation path 2 to the dryer 1.
[0039] Actions of the upgraded brown coal device having the above
configuration will then be described.
[0040] Upgraded brown coal (an example of solid fuel) is obtained
through a mixing step, an evaporation step, a solid-liquid
separation step, and a drying step.
[0041] At the mixing step, porous coal is mixed with mixture oil
containing solvent oil and heavy oil to obtain material slurry.
[0042] At the evaporation step, the material slurry obtained at the
mixing step is heated to promote the dehydration of porous coal. At
the same time, the mixture oil is impregnated into pores of porous
coal to obtain dehydrated slurry.
[0043] At the solid-liquid separation step, upgraded porous coal
and the mixture oil are separated from the dehydrated slurry by the
decanter centrifuge.
[0044] At the drying step, the upgraded porous coal obtained at the
solid-liquid separation step is heated and conveyed to be dried
while being supplied with carrier gas within the dryer 1, to obtain
upgraded brown coal.
[0045] The drying step featuring the present invention will
hereinbelow be described in detail.
[0046] At the drying step, a target value of the carrier gas
circulation amount and a target value of the carrier gas pressure
at the inlet of the dryer 1 are set based on the supply amount of
porous coal supplied into the dryer 1 and on the oil amount
contained in the porous coal at the outlet side of the decanter
centrifuge. In this case, the target value of the carrier gas
circulation amount and the pressure target value are set such that
the carrier gas pressure in the dryer 1 lies within a previously
set pressure range (set pressure range) with respect to the supply
amount of porous coal and the amount of oil contained therein.
These target values to be set may be found in advance by
experiment, etc.
[0047] A control output value is then calculated from Math. 1,
based on the set target value of the carrier gas circulation amount
and on a measured value of the carrier gas flow rate detected by
the flow rate detection sensor 6 (hereinafter, this control output
value is referred to as first control output value). Similarly, a
control output value is calculated from Math. 1, based on the set
target value of the carrier gas pressure and on a measured value of
the carrier gas pressure detected by the first pressure detection
sensor 8 (hereinafter, this control output value is referred to as
second control output value).
MV = 100 P B .times. { e ( t ) + 1 Ti .times. .intg. e ( t ) t + Td
.times. e ( t ) t } [ Math . 1 ] ##EQU00001##
[0048] MV: control output
[0049] e(t): control deviation (target value SV-detected value
PV)
[0050] PB: proportional band (%)
[0051] Ti: integral time (min.) control deviation regulating
parameters
[0052] Td: derivative time (min.)
[0053] Subsequently, by a low select control, the calculated
control output values are compared so that the opening of the first
flow rate regulating valve 7 is adjusted in accordance with a
smaller value.
[0054] When the flow rate and the pressure of carrier gas flowing
through the circulation path 2 are stable, the control output value
is calculated based on a flow rate detected by the flow rate
detection sensor 6 and on the target value so that the opening of
the first flow rate regulating valve 7 is adjusted.
[0055] If the amount of oil evaporating therein increases as a
result of a temporary sudden increase in the amount of upgraded
porous coal conveyed into the dryer 1, the flow rate of carrier gas
detected by the flow rate detection sensor 6 does not vary so much,
but the pressure detected by the first pressure detection sensor 8
rises. In consequence, the second control output value calculated
from Math. 1 becomes smaller than the first control output value.
Thus, the opening of the first flow rate regulating valve 7 is
adjusted based on the second control output value. This suppresses
the flow rate of carrier gas refluxed into the dryer 1 so that the
pressure in the dryer 1 can stably be kept within a desired
range.
[0056] At this time, a control output value is calculated from
Math. 1, based on a pressure detected by the second pressure
detection sensor 11 and on the previously set target value. The
opening of the second flow rate regulating valve 10 is then
adjusted based on the calculated control output value. This
suppresses an excessive pressure rise attributable to carrier gas
within the circulation path 2. Discharged carrier gas is directed
to an off-gas treatment device not shown. Carrier gas delivered to
the off-gas treatment device is properly supplied into the dryer 1
for reuse.
[0057] If the amount of oil occurring therein decreases as a result
of a temporary sudden decrease in the amount of upgraded porous
coal conveyed into the dryer 1, the internal pressure in the dryer
1 and the circulation path 2 lowers. Then, both the flow rate
detected by the flow rate detection sensor 5 and the pressure
detected by the first pressure detection sensor 8 become lower. As
a result, the first control output value and the second control
output value calculated from Math. 1 both become larger.
Ordinarily, the change in the flow rate detected by the flow rate
detection sensor 6 is not so large, and the first control output
value becomes smaller than the second control output value. For
this reason, the first control output value is selected by the low
select control so that the opening of the first flow rate
regulating valve 7 is adjusted based on this first control output
value. In some cases, the second control output value may be
smaller than the first control output value. In this case, the
opening of the first flow rate regulating valve 7 is adjusted based
on the second control output value.
[0058] At this time, similar to the above, a control output value
is calculated from Math. 1, based on a pressure detected by the
second pressure detection sensor 11 and on the previously set
target value. The opening of the second flow rate regulating valve
10 is then adjusted based on the calculated control output value.
In this case, since the detected pressure lowers to a large extent,
the second flow rate regulating valve is fully closed, not
permitting carrier gas to be discharged to the exterior.
[0059] In this manner, if the amount of upgraded porous coal
conveyed into the dryer 1 temporarily increases or decreases, the
opening of the first flow rate regulating valve 7 is adjusted
correspondingly. In this case, by the low select control, a smaller
value is used between the first control output value and the second
control output value. Accordingly, it is possible to stabilize the
pressure of carrier gas in the dryer 1, without a sudden change in
the opening of the first flow rate regulating valve 7.
[0060] The present invention is not limited to the above
configuration described in the embodiment, but may variously be
modified.
[0061] For example, although the opening of the first flow rate
regulating valve 7 is adjusted by a proportional integral
derivative (PID) controller in the embodiment, it may be adjusted
by another feedback control.
[0062] Although in the embodiment, a detection signal from the flow
rate detection sensor 6 is processed by the FIC 12, a detection
signal from the first pressure detection sensor 8 is processed by
the first PIC 13, and a detection signal from the second pressure
detection sensor 11 is processed by the second PIC 15, the
configuration may be, for example, such that these are controlled
together by a single control unit (microcomputer) or such that the
FIC 12 and the first PIC 13 are controlled by a single control unit
(microcomputer).
EXPLANATIONS OF LETTERS OR NUMERALS
[0063] 1 dryer [0064] 2 circulation path [0065] 3 dust collector
[0066] 4 spray tower [0067] 5 blower [0068] 6 flow rate detection
sensor [0069] 7 first flow rate regulating valve [0070] 8 first
pressure detection sensor [0071] 9 exhaust pipe [0072] 10 second
flow rate regulating valve [0073] 11 second pressure detection
sensor [0074] 12 FIC [0075] 13 first PIC [0076] 14 LS circuit
[0077] 15 second PIC
* * * * *