U.S. patent application number 13/250444 was filed with the patent office on 2012-07-05 for biocokes producing method and apparatus.
This patent application is currently assigned to NANIWA ROKI CO., LTD. Invention is credited to Tamio IDA, Yoshimasa KAWAMI, Jun SATOU.
Application Number | 20120168296 13/250444 |
Document ID | / |
Family ID | 42291721 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120168296 |
Kind Code |
A1 |
IDA; Tamio ; et al. |
July 5, 2012 |
BIOCOKES PRODUCING METHOD AND APPARATUS
Abstract
A method of producing biocokes in which pulverized biomass is
fed and pressed in a reaction container is provided, wherein the
pulverized biomass in a substantially-packed state is
pressure-formed while being heated in a temperature range and a
pressure range to obtain a semi-carbonized solid matter or
pre-semi-carbonized solid matter and then cooled to produce
biocoke. The method may includes a filling step; a reaction step;
heating the pulverized biomass by means of a heating device to the
temperature range and keeping such state for a prescribed period of
time to form a shaped matter of the pulverized biomass in the
reaction container, and then cooling the shaped matter by switching
from the heating device to a cooling device; and an ejecting
step.
Inventors: |
IDA; Tamio; (Kowakae,
JP) ; KAWAMI; Yoshimasa; (Kamio-cho, JP) ;
SATOU; Jun; (Sachiura, JP) |
Assignee: |
NANIWA ROKI CO., LTD
Osaka
JP
KINKI UNIVERSITY
Osaka
JP
|
Family ID: |
42291721 |
Appl. No.: |
13/250444 |
Filed: |
September 30, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2010/054821 |
Mar 19, 2010 |
|
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13250444 |
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Current U.S.
Class: |
201/1 ; 201/35;
202/96 |
Current CPC
Class: |
C10B 47/12 20130101;
C10B 53/02 20130101; Y02E 50/14 20130101; Y02P 20/145 20151101;
C10L 9/08 20130101; Y02E 50/10 20130101; C10L 5/447 20130101; Y02E
50/30 20130101 |
Class at
Publication: |
201/1 ; 201/35;
202/96 |
International
Class: |
C10B 47/00 20060101
C10B047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2009 |
JP |
2009-083887 |
Claims
1. A method of producing biocokes in which pulverized biomass is
fed and pressed in a cylindrical reaction container having a bottom
part, the pulverized biomass in a substantially-packed state is
pressure-formed while being heated in a temperature range and a
pressure range to obtain a semi-carbonized solid matter or
pre-semi-carbonized solid matter and then cooled to produce
biocoke, the method comprising: a filling step comprising the
substeps of: feeding the pulverized biomass to the reaction
container; and then pressing the pulverized biomass in the reaction
container by lowering a pressurizing member from above the reaction
container at a pressure lower than the pressure range; a reaction
step comprising the substeps of: pressurizing the pulverized
biomass in the pressure range by increasing a pressure of the
pressurizing member to the pressure range; heating the pulverized
biomass by means of a heating device to the temperature range and
keeping such state for a prescribed period of time to form a shaped
matter of the pulverized biomass in the reaction container; and
then cooling the shaped matter by switching from the heating device
to a cooling device; and an ejecting step comprising the substeps
of: reducing the pressure of the pressurizing member; and then
releasing the bottom part of the reaction container to eject the
shaped matter having been cooled, wherein in the filling step, the
amount of the filled pulverized biomass is estimated by detecting a
position of an upper end of the pulverized biomass fed in the
reaction container using a position sensor or by detecting a period
during the pressurizing member lowering from an initial position to
the upper end of the pulverized biomass.
2. A method of producing biocokes in which pulverized biomass is
fed and pressed in a cylindrical reaction container having a bottom
part, the pulverized biomass in a substantially-packed state is
pressure-formed while being heated in a temperature range and a
pressure range to obtain a semi-carbonized solid matter or
pre-semi-carbonized solid matter and then cooled to produce
biocoke, the method comprising: a filling step comprising the
substeps of: feeding the pulverized biomass to the reaction
container; and then pressing the pulverized biomass in the reaction
container by lowering a pressurizing member from above the reaction
container at a pressure lower than the pressure range; a reaction
step comprising the substeps of: pressurizing the pulverized
biomass in the pressure range by increasing a pressure of the
pressurizing member to the pressure range; heating the pulverized
biomass by means of a heating device to the temperature range and
keeping such state for a prescribed period of time to form a shaped
matter of the pulverized biomass in the reaction container; and
then cooling the shaped matter by switching from the heating device
to a cooling device; and an ejecting step comprising the substeps
of: reducing the pressure of the pressurizing member; and then
releasing the bottom part of the reaction container to eject the
shaped matter having been cooled, wherein in the filling step, a
number of times of lowering the pressurizing member is counted by a
counter in the filling step, and after completing the filling step,
when the detected number of times is lower than an expected number
of times of lowering the pressurizing member expected in a normal
operation state, it is determined that there is an abnormality in
the substep of pressing.
3. The method of producing the biocokes according to claim, 1
wherein in the filling step, the pressure of the pressurizing
member and an amount of the pulverized biomass filled in the
reaction container are detected in the substep of pressing the
pulverized biomass, and the substep of feeding and the substep of
pressing are performed repeatedly until both of the detected
pressure of the pressurizing member and the detected amount of the
filled pulverized biomass are within a set pressure range and a set
amount range of the filling step that are set in advance.
4. The method of producing the biocokes according to claim 1,
wherein in the filling step, a number of times of lowering the
pressurizing member is counted by a counter in the filling step,
and after completing the filling step, when the detected number of
times is lower than an expected number of times of lowering the
pressurizing member expected in a normal operation state, it is
determined that there is an abnormality in the substep of
pressing.
5. The method of producing the biocokes according to claim 1,
wherein the heating device and the cooling device are a
cooling/heating medium circulating unit which introduces one of a
heating medium and a cooling medium to an outer periphery of the
reaction container so as to perform one of heating and cooling of
the pulverized biomass, and wherein, in the reaction step, the
heating medium is circulated for a set period of time and then the
heating medium is replaced by the cooling medium.
6. The method of producing the biocokes according to claim 1,
wherein, in the ejecting step, the shaped matter is pushed and
ejected from an open bottom of the reaction container by lowering
the pressurizing member at a low pressure.
7. An apparatus of producing biocokes comprising: a reaction
container in which pulverized biomass is fed and pressed and which
has a cylindrical shape with a bottom part; a pressurizing member
which pressurizes the pulverized biomass in the reaction container;
a heating device which heats the pulverized biomass within a
temperature range and keeping such state for a prescribed period of
time to form a shaped matter of the pulverized biomass in the
reaction container, the pulverized biomass in a
substantially-packed state being pressure-formed by the
pressurizing member while being heated by the heating device within
a temperature range and a pressure range in which the pulverized
biomass is processed into one of a semi-carbonized solid matter and
a pre-semi-carbonized solid matter so as to produce the shaped
matter of the pulverized biomass; a cooling device which cools the
shaped matter of the pulverized biomass; a pressure detecting
device which detects the pressure of the pressurizing member; a
control unit which controls a pressure of the pressurizing member
and controls switching between the heating device and the cooling
device; and a filling-amount detecting device which detects an
amount of the pulverized biomass pressed in the reaction container,
wherein the filling-amount detecting device is one of a position
sensor which detects a position of an upper end the pulverized
biomass fed in the reaction container and a device which detects a
period during the pressurizing member lowering from an initial
position to the upper end of the pulverized biomass so as to
estimate the amount of the filled pulverized biomass based on one
of the detected position and the detected period.
8. The apparatus of producing the biocokes according to claim 7,
wherein the control unit controls a pressure loaded on the
pulverized biomass to a first pressure stage which is below the
pressure range and a second pressure stage which is within the
pressure range, the pulverized biomass being pressed during filling
in the reacting container in the first pressure stage and being
then pressurized within the pressure range in the second pressure
stage, and wherein the heating device is controlled to operate at
the second pressure stage of the pressurizing member for a
prescribed period of time and then switched to the cooling device
after the prescribed period of time.
9. The apparatus of producing the biocokes according to claim 7,
wherein the control unit performs a control in the first pressure
stage such that feeding of the pulverized biomass and the pressing
of the pulverized biomass in the reaction container are performed
repeatedly until the pressure detected by the pressure detecting
device and the amount of the filled pulverized biomass detected by
the filling-amount detecting device are within a set pressure range
and a set amount range that are set in advance.
10. The device of producing the biocokes according to claim 7,
wherein the control unit comprises a counter which counts a number
of times of lowering the pressurizing member when switching the
pressure stages of the pressurizing member, the control unit
stopping the pressurizing member when it is determined that there
is an abnormality during the pressing in such a case that the
detected number of times is lower than an expected number of times
of lowering the pressurizing member expected in a normal operation
state.
11. The device of producing the biocokes according to claim 7,
wherein the heating device and the cooling device are a
cooling/heating medium circulating unit which introduces one of a
heating medium and a cooling medium to an outer periphery of the
reaction container so as to perform one of heating and cooling of
the pulverized biomass.
12. The method of producing the biocokes according to claim 2,
wherein in the filling step, the pressure of the pressurizing
member and an amount of the pulverized biomass filled in the
reaction container are detected in the substep of pressing the
pulverized biomass, and the substep of feeding and the substep of
pressing are performed repeatedly until both of the detected
pressure of the pressurizing member and the detected amount of the
filled pulverized biomass are within a set pressure range and a set
amount range of the filling step that are set in advance.
13. The method of producing the biocokes according to claim 2,
wherein the heating device and the cooling device are a
cooling/heating medium circulating unit which introduces one of a
heating medium and a cooling medium to an outer periphery of the
reaction container so as to perform one of heating and cooling of
the pulverized biomass, and wherein, in the reaction step, the
heating medium is circulated for a set period of time and then the
heating medium is replaced by the cooling medium.
14. The method of producing the biocokes according to claim 2,
wherein, in the ejecting step, the shaped matter is pushed and
ejected from an open bottom of the reaction container by lowering
the pressurizing member at a low pressure.
15. The device of producing the biocokes according to claim 8,
wherein the control unit comprises a counter which counts a number
of times of lowering the pressurizing member when switching the
pressure stages of the pressurizing member, the control unit
stopping the pressurizing member when it is determined that there
is an abnormality during the pressing in such a case that the
detected number of times is lower than an expected number of times
of lowering the pressurizing member expected in a normal operation
state.
Description
[0001] This is a continuation of International Application
PCT/JP2010/054821 (published as WO 2010/0113679 A1) having an
international filing date of Mar. 19, 2010, which claims priority
to JP 2009-083887 filed on Mar. 31, 2009. The disclosures of the
PCT application and the priority application, in their entity,
including the drawings, claims, and the specifications thereof, are
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to the field of producing
biocokes using biomass as a raw material, and particularly to a
biocoke producing method and a biocoke producing apparatus, which
enable industrial mass production of bio-cokes which can be used as
substitute fuel for coal cokes.
BACKGROUND ART
[0003] In view of global worming, reduction of CO.sub.2 emission is
promoted. Especially, in a steel industry, coal cokes which are
fossil fuels are used as fuel and reducing agents at combustion
facilities like a Cupola furnace and a power furnace. At combustion
facilities like power boiler, fossil fuels such as coal and heavy
oil are often used as fuel. However, these fossil fuels are a cause
of global warming from a perspective of CO.sub.2 emission, and thus
the use thereof is becoming more regulated in the view of
protecting the global environment. Also from a perspective of
fossil fuel drain, there is a need for developing a substitute
energy source and putting such substitute energy into practical
use.
[0004] It has been promoted to use biomass which does not affect on
an amount of CO2 emission in the atmosphere instead of fossil fuel.
Biomass is an organic matter attributed to photosynthesis such as
ligneous matters, grass plants, crops, and kitchen waste. By
processing these types of biomass for fuel, it becomes possible to
utilize biomass as an energy source or an industrial raw material.
This contributes to an environmental preservation. The biomass can
be transformed into fuel by drying the biomass to fuel or by
pressurizing biomass to a fuel pellet, or by carbonizing and drying
to fuel in a solid form or liquid form. However, in the drying
method, air ratio in the dried biomass remains large and apparent
specific gravity is small, thus making it difficult to transport or
store such fuel. This form of fuel is not very efficient for long
distance transportation or storage.
[0005] A method of processing biomass into a fuel pellet is
disclosed in JP 61-27435A. This method includes the steps of
adjusting moisture content of comminuted fibrous particles to 16%
to 28% by weight, and compressing the material in a die to dry into
the fuel pellet. A method of carbonizing the biomass (destructive
distillation) is disclosed in JP2003-206490A. According to this
method, in oxygen-depleted environment biomass is heated at 200 to
500.degree. C., preferably 250 to 400.degree. C., thus to produce a
precursor of charred compact fuel of biomass.
[0006] However, according to the method disclosed in JP 61-27435A,
biomass is processed into fuel by compacting, processed fuel pallet
contains too much moisture and heat value is low, which is not
suitable as fuel. Moreover, according to the destructive
distillation method disclosed in JP2003-206490A and other
references, processed biomass has more value as fuel than
unprocessed biomass but still has low apparent specific gravity and
has low calorific value in comparison to coal cokes. It also has
lower hardness compared to coal cokes, which is not suitable to
substitute for coal cokes.
[0007] Recently, as an alternative to coal cokes, biocokes are
being studied based on JP 4088933 B. The biocoke is produced by
pressing and heating biomass raw material for a given period of
time and then cooling the biomass raw material in a pressurized
state. The pressurizing and heating conditions are set within the
pressure and temperature range inducing thermal decomposition of
hemicellulose or thermal hardening of cellulose and lignin within
the pulverized biomass to induce the pulverized biomass to react at
a low temperature while maintaining a structure of cellulose and
lignin, thereby obtaining a semi-carbonized solid matter or
pre-semi-carbonized solid matter. In this way, reaction mechanism
is established and biocoke with high hardness and high density is
produced. The pulverized biomass is mainly composed of lignin,
cellulose and hemicellulose.
[0008] With the reaction mechanism under the above-identified
condition, hemicellulose being a fiber component of the pulverized
biomass is thermally decomposed and develops adhesion effect, and
free water contained in the pulverized biomass induces lignin to
react at a low temperature keeping its structure under the
above-identified pressurizing and heating condition, which acts
with consolidation effect synergistically, thereby producing
biocoke with high hardness and high density. The thermal hardening
reaction makes progress as reaction activity spots are induced
amongst phenolic macromolecules contained in lignin or the
like.
[0009] FIG. 8 is a table comparing physical properties of biocokes
with those of other fuels. The values shown in the table were
obtained in experiments, thus should not limit the present
invention. As shown in the table, properties of biocoke are
apparent specific gravity 1.2 to 1.52, maximum compressive strength
20 to 200 MPa, heat value 18 to 23 MJ/kg, also showing excellence
in hardness and combustibleness, while properties of wood biomass
are apparent specific gravity 0.4 to 0.6, maximum compressive
strength 30 MPa, heat value 17 MJ/kg, also showing inferior
performance in hardness and combustibleness to biocoke. Properties
of coal coke are apparent specific gravity 1.85, maximum
compressive strength 15 MPa, heat value 29 MJ/kg but biocoke still
shows superior performance in combustibleness and hardness.
Consequently, not only biocoke is a functional substitute of coal
cokes but also biocoke posses a high value as a material.
SUMMARY OF INVENTION
[0010] Bio-cokes are still in the experiment stage. JP 4088933 B
does not disclose a detailed structure of a pressurizing device, a
heating device, a cooling device or the like and a control method
thereof or how to produce biocokes in a short amount of time and
efficiently. Therefore, it is an object of the present invention to
provide biocokes producing method and apparatus which can produce
biocokes efficiently and in a short amount of time.
[0011] In view of the above problems, a first aspect of the present
invention is a method of producing biocokes in which pulverized
biomass is fed and pressed in a cylindrical reaction container
having a bottom part, the pulverized biomass in a
substantially-packed state is pressure-formed while being heated in
a temperature range and a pressure range to obtain a
semi-carbonized solid matter or pre-semi-carbonized solid matter
and then cooled to produce biocoke. The method of producing the
biocokes may include, but is not limited to, a filling step
comprising the substeps of: feeding the pulverized biomass to the
reaction container; and then pressing the pulverized biomass in the
reaction container by lowering a pressurizing member from above the
reaction container at a pressure lower than the pressure range; and
a reaction step comprising the substeps of pressurizing the
pulverized biomass in the pressure range by increasing a pressure
of the pressurizing member to the pressure range; heating the
pulverized biomass by means of a heating device to the temperature
range and keeping such state for a prescribed period of time to
form a shaped matter of the pulverized biomass in the reaction
container; and then cooling the shaped matter by switching from the
heating device to a cooling device; an ejecting step comprising the
substeps of: reducing the pressure of the pressurizing member; and
then releasing the bottom part of the reaction container to eject
the shaped matter having been cooled.
[0012] In the first aspect of the present invention, in the filling
step, the pressurizing member is operated first in the first
pressure stage to press the pulverized biomass. Next in the
reaction step, the pressure of the pressurizing member is increased
and in synchronization with this, the heating device is actuated to
heat and pressurize the pulverized biomass in an
substantially-sealed state in the temperature and pressure range of
obtaining the semi-carbonized or pre-semi carbonized solid matter.
After keeping the pressurized and heated state for a prescribed
period of time, the heating device is switched to the cooling
device to cool the pulverized biomass while still maintaining the
pressurized state, thereby producing the shaped matter of biocokes.
In this manner, the pressurizing member and the heating device and
the cooling device are controlled in conjunction. Thus, it is
possible to produce biocokes in a short amount of time and
efficiently. Further, the biomass of a small grain size is used and
thus, bulk density is low. On the other hand, by using unprocessed
biomass, it requires a large reaction container. However, in the
first aspect of the present invention, the pulverized biomass is
pressed at low pressure by the pressurizing member in the filling
step and thus, it is possible to input a larger amount of the
pulverized biomass. As a result, the reaction container can be
downsized.
[0013] In the filling step, the pressure of the pressurizing member
and an amount of the pulverized biomass filled in the reaction
container may be detected in the substep of pressing the pulverized
biomass, and the substep of feeding and the substep of pressing may
be performed repeatedly until both of the detected pressure of the
pressurizing member and the detected amount of the filled
pulverized biomass are within a set pressure range and a set amount
range of the filling step that are set in advance. By this, it is
possible to produce biocokes of the same size without measuring an
input amount of the pulverized biomass before inputting to the
reaction container, thereby enhancing a product value of the
produced biocokes.
[0014] In the filling step, the amount of the filled pulverized
biomass may be estimated by detecting a position of an upper end of
the pulverized biomass fed in the reaction container using a
position sensor or by detecting a period during the pressurizing
member lowering from an initial position to the upper end of the
pulverized biomass. By this, it is possible to detect the amount of
the pulverized biomass filled in the reaction container.
Particularly, detection can be preferred with precision by using
the position sensor, whereas the device can be produced at low cost
by using the period of lowering the pressurizing member.
[0015] In the filling step, a number of times of lowering the
pressurizing member may be counted by a counter in the filling
step, and after completing the filling step, when the detected
number of times is lower than an expected number of times of
lowering the pressurizing member expected in a normal operation
state, it may be determined that there is an abnormality in the
substep of pressing. In such a case that the number of times of
lowering the pressurizing member is lower than the expected number
of times expected in the normal operation state, it is assumed that
the pressurizing member failed to lower properly due to occurrence
of abnormality such as the pressurizing member getting stuck near
the inlet of the reaction container. Therefore, it is possible to
detect abnormalities during pressurizing the pulverized biomass in
a simple manner by counting the number of times of lowering the
pressurizing member.
[0016] In the above method of producing the biocokes, the heating
device and the cooling device may be a cooling/heating medium
circulating unit which introduces one of a heating medium and a
cooling medium to an outer periphery of the reaction container so
as to perform one of heating and cooling of the pulverized biomass,
and in the reaction step, the heating medium may be circulated for
a set period of time and then the heating medium may be replaced by
the cooling medium. In this manner, the cooling/heating medium
circulating unit is used as the heating device and the cooling
device. Thus, the pulverized biomass is heated or cooled rapidly
and switching between heating and cooling of the pulverized biomass
can be performed smoothly.
[0017] In the ejecting step, the shaped matter may be pushed and
ejected from an open bottom of the reaction container by lowering
the pressurizing member at a low pressure. By pushing and ejecting
the shaped matter of the pulverized biomass by means of the
pressurizing member, the biocokes which is shaped in a consolidated
manner within the reaction container can be easily ejected.
[0018] A second aspect of the present invention is an apparatus of
producing biocokes which may include, but is not limited to: a
reaction container in which pulverized biomass is fed and pressed
and which has a cylindrical shape with a bottom part; a
pressurizing member which pressurizes the pulverized biomass in the
reaction container; a heating device which heats the pulverized
biomass within a temperature range and keeping such state for a
prescribed period of time to form a shaped matter of the pulverized
biomass in the reaction container, the pulverized biomass in a
substantially-packed state being pressure-formed by the
pressurizing member while being heated by the heating device within
a temperature range and a pressure range in which the pulverized
biomass is processed into one of a semi-carbonized solid matter and
a pre-semi-carbonized solid matter so as to produce the shaped
matter of the pulverized biomass; a cooling device which cools the
shaped matter of the pulverized biomass; and a control unit which
controls a pressure of the pressurizing member and controls
switching between the heating device and the cooling device. The
control unit may control a pressure loaded on the pulverized
biomass to a first pressure stage which is below the pressure range
and a second pressure stage which is within the pressure range, the
pulverized biomass being pressed during filling in the reacting
container in the first pressure stage and being then pressurized
within the pressure range in the second pressure stage, and the
heating device may be controlled to operate at the second pressure
stage of the pressurizing member for a prescribed period of time
and then switched to the cooling device after the prescribed period
of time.
[0019] The apparatus of producing the biocokes may also include: a
pressure detecting device which detects the pressure of the
pressurizing member; and a filling-amount detecting device which
detects an amount of the pulverized biomass pressed in the reaction
container. The control unit may perform a control in the first
pressure stage such that feeding of the pulverized biomass and the
pressing of the pulverized biomass in the reaction container are
performed repeatedly until the pressure detected by the pressure
detecting device and the amount of the filled pulverized biomass
detected by the filling-amount detecting device are within a set
pressure range and a set amount range that are set in advance.
[0020] The filling-amount detecting device may be one of a position
sensor which detects a position of an upper end the pulverized
biomass fed in the reaction container and a device which detects a
period during the pressurizing member lowering from an initial
position to the upper end of the pulverized biomass so as to
estimate the amount of the filled pulverized biomass based on one
of the detected position and the detected period. Further, the
control unit may include a counter which counts a number of times
of lowering the pressurizing member when switching the pressure
stages of the pressurizing member, the control unit stopping the
pressurizing member when it is determined that there is an
abnormality during the pressing in such a case that the detected
number of times is lower than an expected number of times of
lowering the pressurizing member expected in a normal operation
state. Furthermore, the heating device and the cooling device may
be a cooling/heating medium circulating unit which introduces one
of a heating medium and a cooling medium to an outer periphery of
the reaction container so as to perform one of heating and cooling
of the pulverized biomass.
[0021] In the present invention, in the filling step, the
pressurizing member is operated first in the first pressure stage
to press the pulverized biomass. Next in the reaction step, the
pressure of the pressurizing member is increased and in
synchronization with this, the heating device is actuated to heat
and pressurize the pulverized biomass in an substantially-sealed
state within the temperature and pressure range of obtaining the
semi-carbonized or pre-semi carbonized solid matter. After keeping
the pressurized and heated state for a prescribed period of time,
the heating device is switched to the cooling device to cool the
pulverized biomass while still maintaining the pressurized state,
thereby producing the shaped matter of biocokes. In this manner,
the pressurizing member and the heating device and the cooling
device are controlled in conjunction. Thus, it is possible to
produce biocokes in a short amount of time and efficiently.
Further, the biomass of a small grain size is used and thus, bulk
density is low. On the other hand, by using unprocessed biomass, it
requires a large reaction container. However, in the first aspect
of the present invention, the pulverized biomass is pressed at low
pressure by the pressurizing member in the filling step and thus,
it is possible to input a larger amount of the pulverized biomass.
As a result, the reaction container can be downsized.
[0022] In the filling step, the pressure of the pressurizing member
and the amount of the pulverized biomass filled in the reaction
container is detected in the substep of pressing the pulverized
biomass, and the substep of feeding and the substep of pressing are
performed repeatedly until both of the detected pressure of the
pressurizing member and the detected amount of the filled
pulverized biomass are within the set pressure range and the set
amount range of the filling step that are set in advance. Thus, it
is possible to produce biocokes of the same size without measuring
an input amount of the pulverized biomass before inputting to the
reaction container, thereby enhancing a product value of the
produced biocokes. Further, in the filling step, the amount of the
filled pulverized biomass is estimated by detecting a position of
an upper end of the pulverized biomass fed in the reaction
container using a position sensor or by detecting a period during
the pressurizing member lowering from an initial position to the
upper end of the pulverized biomass. Thus, it is possible to easily
detect the filling amount of the pulverized biomass.
[0023] Further, the cooling/heating medium circulating unit is used
as the heating device and the cooling device. Thus, the pulverized
biomass can be heated or cooled rapidly and switching between
heating and cooling of the pulverized biomass can be performed
smoothly. In the ejecting step, the shaped matter is pushed and
ejected from an open bottom of the reaction container by lowering
the pressurizing member at a low pressure. Thus, it is possible to
easily eject the biocokes which is shaped in a consolidated manner
within the reaction container.
BRIEF DESCRIPTION OF DRAWINGS
[0024] The invention will be described with reference to certain
preferred embodiments thereof, wherein:
[0025] FIG. 1 is a cross-sectional view illustrating a structure of
an apparatus of producing biocokes in relation to a preferred
embodiment of the present invention;
[0026] FIG. 2 is a flow chart showing a process of producing
biocokes in relation to a preferred embodiment of the present
invention;
[0027] FIG. 3 is an explanatory view of an operation of the
apparatus of producing biocokes in the filling step in a preferred
embodiment of the present invention;
[0028] FIG. 4 is an explanatory view of an operation of the
apparatus of producing biocokes in the reaction step in a preferred
embodiment of the present invention;
[0029] FIG. 5 is an explanatory view of an operation of the
apparatus of producing biocokes in the ejecting step in a preferred
embodiment of the present invention;
[0030] FIG. 6 shows a hydraulic circuit of a hydraulic
pressurization mechanism in relation to a preferred embodiment of
the present invention;
[0031] FIG. 7 shows a system structure of the apparatus of
producing biocokes equipped with a cooling/heating medium circuit
in relation to a preferred embodiment of the present invention;
and
[0032] FIG. 8 is a comparative chart of properties of biocokes.
DESCRIPTION OF EMBODIMENTS
[0033] A preferred embodiment of the present invention will now be
described in detail with reference to the accompanying drawings. It
is intended, however, that unless particularly specified,
dimensions, materials, shape, its relative positions and the like
shall be interpreted as illustrative only and not limitative of the
scope of the present invention. In the present invention, biomass
used as raw material for producing biocokes is organic matter
attributed to photosynthesis. The biomass may be ligneous matters,
grass plant, crops, agricultural matters, or the like. For example,
biomass may be lumber waste, thinned lumber, pruned branches,
plants, agricultural waste and kitchen waste such as coffee grinds
and used tea leaves.
[0034] In a preferred embodiment of the present invention,
pulverized biomass whose moisture content is adjusted to a
prescribed percentage of moisture content as needed, is used as a
raw material. The pulverized biomass may be biomass of a small
grain size such as used tea leaves and coffee grinds without being
processed or biomass of a large grain size such as lumber waste
which has been pulverized to a prescribed grain size or smaller. In
a biocokes-producing apparatus of the preferred embodiment,
pulverized biomass in a substantially packed state is
pressure-formed while being heated in a temperature range and a
pressure range to obtain a semi-carbonized solid matter or
pre-semi-carbonized solid matter and after a certain period of
time, cooled while keeping a state of pressurization. As a result,
biocokes are produced. The above-described temperature and pressure
ranges are set within such ranges as to obtain the semi-carbonized
solid matter or the pre-semi-carbonized solid matter by inducing
the pulverized biomass to react at a low temperature while inducing
thermal decomposition of hemicellulose and maintaining a structure
of cellulose and lignin within the pulverized biomass.
Specifically, in the above-described temperature and pressure
ranges, hemicellulose within the pulverized biomass is thermally
decomposed and lignin is induced to thermally harden. The
pulverized biomass is mainly composed of lignin, cellulose and
hemicellulose.
[0035] A basic structure of the biocokes-producing apparatus of the
preferred embodiment is explained in reference to FIG. 1. FIG. 1
shows the biocokes-producing apparatus 1 having a cylindrical
reaction container 2 to which the pulverized biomass 11 is
inputted. At an upper part of the reaction container 2, a hopper 3
is provided to receive the pulverized biomass 11. At a lower part
of the reaction container 2, an ejecting part 5 is provided to
eject the biocokes having been shaped. The reaction container 2 is
equipped with a heating device which heats a content of the
reaction container 2 to a prescribed temperature and a cooling
device which cools the content having been heated. The heating
device and the cooling device may be one temperature-regulating
device. In the preferred embodiment, the temperature-regulating
device has a double tube structure configured such that a jacket is
provided around the reaction container 2 to form a cooling/heating
medium path 4 between an inner tube and an outer tube. A cooling
medium or a heating medium (hereinafter referred to as
cooling/heating medium) flows through the cooling/heating medium
path 4 to perform heat exchange with the pulverized biomass 11
filled in the inner tube, thereby taking and receiving thermal
energy. A medium inlet 4a is arranged on a lower side of the
cooling/heating medium path 4 and a medium outlet 4b is arranged on
an upper side of the cooling/heating medium path 4. The medium
inlet 4a and the medium outlet 4b are connected to a
cooling/heating medium circuit which is described later (see FIG.
7). A mechanism which includes the cooling/heating medium path 4,
the medium inlet 4a, the medium outlet 4b and the cooling/heating
medium circuit and which regulates a temperature of the reaction
container 2 by switching between the cooling medium and the heating
medium is called a cooling/heating medium circulating
mechanism.
[0036] The ejecting part 5 has an opening that is the same in
diameter as that of the reaction container. Below the ejecting
part, an ejecting device is provided to open and close the ejecting
part 4. The ejecting device has a bottom cover 9 to cover the
ejecting part 5 and a hydraulic ejection mechanism 10 to control
releasing of the ejecting part 5. After completing the reaction
step within the reaction container 2, the ejecting device drives
the hydraulic ejection mechanism 10 to slid the bottom cover 9 and
release the ejecting part 5, thereby ejecting the biocokes from the
cylinder 2. Over the reaction container 2, a pressurizing device is
provided to pressurize the pulverized biomass 11 within the
cylinder 2 to a prescribed pressure. The pressurizing device
includes a pressurizing piston (a pressurizing member) 6 and a
hydraulic pressurization mechanism 8 (see FIG. 6). The pressurizing
piston 6 is driven by a pressurizing cylinder 7 to reciprocate in
the reaction container 2. The hydraulic pressurization mechanism 8
regulates a hydraulic pressure in the pressurizing cylinder 7. The
pressurizing piston 6 and the pressurizing cylinder 7 are coaxially
arranged with the reaction container. The pressurizing piston 6
lowers to near the bottom part of the reaction container 2. The
pressurizing piston 6 is operable to maintain the pressurized state
for a prescribed period of time. Further, a position sensor 20 may
be provided to detect a position of the pressurizing piston 6 in a
longitudinal direction based on an extending and retracting amount
of the pressurizing piston 6.
[0037] The hydraulic pressurization mechanism 8, the hydraulic
ejection mechanism 10 and the cooling/heating medium circulation
mechanism are controlled by a control unit 100. The control unit
100 is constituted of a microcomputer which includes a CPU, a ROM,
a RAM and an I/O interface. The control unit 100 further includes a
counter 101 and a timer 102. The counter 101 counts a number of
times of lowering the pressurizing piston 6 of the hydraulic
pressurization mechanism 8. The timer 102 detects a period of time
of a prescribed control.
[0038] FIG. 6 shows an example of a hydraulic circuit of the
hydraulic pressurization mechanism. The operating oil is pumped
from a tank 76 by a pump 77 and supplied to the pressurizing
cylinder 7 through an electromagnetic valve 78 which regulates a
supply amount of the operating oil. In a hydraulic circuit between
the electromagnetic valve 78 and the pressurizing cylinder 7, check
valves 71 and 72 are provided. The pressure of the operating oil at
the position is detected by a pressure sensor 75 as a back pressure
and the detected back pressure is inputted to the control unit 100
as a pressure of the pressurizing piston 6. Based on the pressure
detected by the pressure sensor 75, the control unit 100 controls
the electromagnetic valve 78 to adjust a pressure of the
pressurizing piston 6. A pressure stage of the pressurizing piston
6 has at least first and second pressure stages. In the first
pressure stage, the pulverized biomass 11 is pressed during filling
thereof at a pressure below a pressure range in which the
pulverized biomass 11 is processed into one of a semi-carbonized
solid matter and a pre-semi-carbonized solid matter. In the second
pressure stage, the pulverized biomass 11 having been pressed is
pressurized within the above pressure range.
[0039] An example of the cooling/heating medium circuit 30 having
the cooling/heating medium circulation mechanism is explained in
reference to FIG. 7.
[0040] By using the cooling/heating medium circuit 30, the
temperature-regulating device can obtain high thermal efficiency
and safety. It is also possible to use a cooling/heating medium
circuit of a different structure. In the cooling/heating medium
circuit 30, silicon oil is used as the cooling and heating medium.
The medium inlet 4a and the medium outlet 4b of the reaction
container 2 are connected to the cooling/heating medium circuit
shown in the drawing. The cooling/heating medium circuit 30 is
configured by combining a cooling medium circuit and a
heating-medium circuit. The medium outlet 4b is connected to a
medium ejection line 41 and branches into a heating-medium return
line 42 and a cooling medium return line 43 at a three-way valve 45
disposed in the medium ejection line 41. The heating-medium return
line 42 is connected to a heating-medium tank 31. The
heating-medium tank 31 is equipped with a heater 31a and a stirrer
31b to raise a temperature of the heating medium having been
cooled. Preferably N.sub.2 gas is supplied from a N.sub.2 gas
cylinder as needed and it is kept in an inert atmosphere inside the
tank to ensure the safety. An outlet side of the heating-medium
tank 31 is connected to a cooling/heating medium supply line 40 via
a three-way valve 46. With the above structure, during heating of
the reaction container 2, the three-way valves 45 and 46 are
controlled to circulate the heating medium toward the
heating-medium tank 31 and thus, the heating-medium circuit is
formed by the heating-medium tank 31, the cooling/heating medium
supply line 40, the cooling/heating medium path 4 (the reaction
container 2), the medium ejection line 41 and the heating-medium
return line 42.
[0041] The cooling-medium return line 43 is connecting to a
cooling/heating medium exchanger 36. The heating/cooling medium
exchanger 36 cools the cooling medium by heat exchange with cooling
water such as clean water. Preferably, a cooling-medium tank 35 is
provided on an upstream side of the cooling/heating medium
exchanger 36 in the cooling-medium return line 43. The
cooling-medium tank 35 is capable of cooling the cooling medium at
least to a boiling temperature or below, preferably to 80.degree.
C. or below. The cooling-medium tank 35 is preferably provided with
a stirrer 35a. This suppresses a temperature change of the
cooling-medium at the outlet of the cooling-medium tank 35, thereby
enhancing the cooling performance. With the above structure, during
cooling of the reaction container 2, the three-way valves 45 and 46
are controlled to switch from the heating-medium tank side to the
cooling-medium tank side to circulate the cooling medium to the
heating-medium tank 31 and thus, the cooling-medium circuit is
formed by the cooling-medium tank 35, the cooling/heating medium
exchanger 36, the cooling/heating medium supply line 40, the
cooling/heating medium path 4 (the reaction container 2), the
medium ejection line 41 and the cooling-medium return line 43. In
this manner, the cooling/heating medium circulation mechanism with
the cooling/heating medium circuit 30 is used as the heating device
and the cooling device for heating and cooling the pulverized
biomass 11 in the reaction container 2. Thus, the pulverized
biomass 11 is heated or cooled rapidly and switching between
heating and cooling of the pulverized biomass 11 can be performed
smoothly.
[0042] A process of producing biocokes in relation to the preferred
embodiment is explained in reference to FIG. 2. A first step of the
process is a filling step. In a step S1, the control unit 100
operates to start a filling operation. In a step S2, each hydraulic
mechanism including the hydraulic pressurization mechanism 8 and
the hydraulic ejection mechanism 10 is started as well as the
cooling/heating medium circulation mechanism. In a step S3, the
counter 101 is reset. Specifically, it is set to X=0,x being the
number of times of filling the pulverized biomass 11. Meanwhile,
the pressurizing piston 6 is arranged at an initial position Ho
above the reaction container 2 as shown in a stage (i) of FIG. 3.
In a step S4, the pulverized biomass 11 as a raw material is
inputted into the reaction container 2 from the hopper 3. Next, in
a step S5, the pressurizing cylinder 7 is driven to lower at a low
pressure by the hydraulic pressurization mechanism 8. The pressure
of the pressurizing cylinder 7 when lowering at low pressure is set
to a first pressure stage Pi being lower than a pressure of the
reaction step which is described later. Meanwhile, in a step S6,
the number of filling is increased by +1 in the counter 101, i.e.
X.sub.0=X.sub.0+1. When lowering the pressurizing cylinder 7 at low
pressure, in a step S7, it is monitored in the control unit 100
whether or not the hydraulic pressure P of the pressurizing
cylinder 7 is higher than the prescribed pressure P.sub.1. In such
a case that the period of pressurization detected by the timer 102
has passed beyond a preset prescribed period when the hydraulic
pressure P of the pressurizing cylinder 7 is not higher than the
prescribed pressure P.sub.1, the process returns to the step S5 to
drive the pressurizing cylinder 7 to lower. Preferably, the first
stage pressure P.sub.1 at which the pulverized biomass is pressed
in the filling step is set to 14 MPa and the preset prescribed
period is set to ten seconds.
[0043] On the other hand, in such a case that the period of
pressurization detected by the timer 102 has passed beyond the
preset prescribed period when the hydraulic pressure P of the
pressurizing cylinder 7 is higher than the prescribed pressure
P.sub.1, a filling amount of the pulverized biomass 11 in the
reaction container 2 is detected so that the pulverized biomass 11
is shaped into a target size. The detection of the filling amount
of the pulverized biomass 11 is performed as below. The position
sensor 20 detects a position H of an upper end of the pulverized
biomass 11 fed in the reaction container 2. Then, it is determined
whether or not the detected position H is not less than a preset
filling amount H.sub.1, i.e. H.gtoreq.H.sub.1.
[0044] Alternatively, the filling amount of the pulverized biomass
11 may be estimated by detecting a period during the pressurizing
member 6 lowering from the initial position H.sub.1 to the upper
end H of the pulverized biomass by means of the timer 102. In this
case, the period during the pressurization member 6 lowering from
the initial position Hi to the upper end H is obtained in advance
as a set period T.sub.1. In a step S8, it is determined whether or
not the detected period T is not greater than the set period
T.sub.1, T.ltoreq.T.sub.1. In this manner, by using the position
sensor or the period T during the pressurizing member 6 lowering
from H.sub.1 to H, it is possible to detect the filling amount of
pulverized biomass 11. Particularly, detection can be preferred
with precision by using the position sensor 20, whereas the device
can be produced at low cost by using the period of lowering the
pressurizing piston 6.
[0045] As shown in a stage (ii) of FIG. 3, when the position H of
the pulverized biomass 11 in the reaction container 2 has not
reached the target position H.sub.1 (H<H.sub.1) or when the
period T during the pressurizing cylinder 7 lowering from Hi to H
is longer than the set period T.sub.1 (T>T.sub.1), it is
determined that the filling amount is insufficient and the
pressurizing cylinder 7 is driven upward in a step S11. Next, in a
step S12, it is determined whether or not the hydraulic pressure P
of the pressurizing cylinder 7 is greater than the prescribed
pressure P.sub.1. When it is determined P>P.sub.1, the process
returns to the step S11 to drive the pressurizing cylinder 7
upward. In contrast, when it is determined P<P.sub.1, the
process returns to the step S4 to input the pulverized biomass 11
again as shown in a stage (iii) of FIG. 3 and the filling step of
the pressurizing cylinder 7 of S4 and beyond is repeated. Such
repeated operation is stopped once the hydraulic pressure P of the
pressurizing cylinder 7 becomes greater than the prescribed
pressure P.sub.1 and the filling amount H of the pulverized biomass
11 becomes not lower than the preset filling amount H.sub.1. In
this manner, by performing the filling step, it is possible to
produce biocokes of the same size without measuring an input amount
of the pulverized biomass 11 before inputting to the reaction
container 2. Further, the biomass of a small grain size is used and
thus, bulk density is low. On the other hand, by using unprocessed
biomass, the reaction container 2 must be made larger. In the
preferred embodiment, in the filling step, the pulverized biomass
is pressed at low pressure by the pressurizing piston 6, and thus,
it is possible to input a larger amount of the pulverized biomass
11. As a result, the reaction container is downsized.
[0046] When it is determined in the step S8 that the filling amount
of the pulverized biomass 11 has reached the target filling amount,
the process advances to a step S9 to determine whether or not the
number of filling the pulverized biomass detected by the counter
101, X.sub.0 is less than the prescribed number of filling, Xa. In
such a case that X0 is less than the prescribed number of filling,
Xa, it is assumed that the pressurizing piston 6 failed to lower
properly due to occurrence of abnormality such as the pressurizing
piston 6 getting stuck near the inlet of the reaction container 2
and the device is halted in a step S10. In such a case that X.sub.0
is not less than the prescribed number of filling, Xa, the process
advances to the reaction step. In this manner, the number of
filling the pulverized biomass detected by the counter 101, X.sub.0
is counted by the counter 101 so as to detect abnormality during
pressing the pulverized biomass 11 easily in real time.
[0047] In the reaction step, in a step S13, the pressurizing
cylinder 7 is driven downward at high pressure to lower the
pressurizing piston 6 as shown in FIG. 4. By this, the pulverized
biomass 11 is pressurized at a prescribed pressure range P2 (second
pressure stage) which is required to induce the pulverized biomass
11 to react. In a step S14, the pulverized biomass 11 is heated in
the prescribed temperature range by circulating the heating medium
in the cooling/heating medium path 4 of the reaction container 2.
The prescribed temperature range P2 is set to the pressure and
temperature range which induces thermal decomposition or thermal
hardening of hemicellulose and lignin within the pulverized
biomass. Preferably, the prescribed pressure range P2 is set 8 to
25 MPa and the temperature range is set to 115 to 230.degree. C.
The pulverized biomass 11 within the reaction container 2 is
maintained in the above-described pressurized and heated state for
a set period of time. For instance, when the radius of the cylinder
is 50 mm, the pulverized biomass 11 is maintained in the
above-described pressurized and heated state for 10 to 20 minutes,
whereas, when the radius of the cylinder is 150 mm, the pulverized
biomass 11 is maintained in the above-described pressurized and
heated state for 30 to 60 minutes. In a step S15, it is determined
by the timer 102 whether or not the heating-medium circulation
period is over. Once the heating-medium circulation period is over,
the cooling/heating medium circulation mechanism is switched from
the heating medium to the cooling medium to start circulation of
the cooling medium to the cooling/heating medium path 4 in a step
S16. In a manner similar to the above case, it is determined in a
step S17 whether or not the cooling-medium circulation period is
over. Once the cooling-medium circulation period is over, the
circulation of the cooling medium is stopped and the process
advances to the ejecting step.
[0048] In the ejecting step, in a step S18, the pressurizing
cylinder 7 is depressurized as shown in FIG. 5 and in a step S19,
the hydraulic ejection mechanism 10 is driven to slide the bottom
cover 9 and release the ejecting part 5. Next, in a step S20, the
pressurizing cylinder 7 is driven to lower at a low pressure to
push out the biocokes 19 produced in the reaction container 2 as
show in a stage(ii) of FIG. 5. By this, the biocokes 19 which is
shaped in a consolidated manner within the reaction container can
be easily ejected. Meanwhile, in a step S21, it is determined
whether or not the position of the pressurizing piston 6 detected
by the position sensor 20 has reached a downward limit of the
pressurizing position 6. When the pressurizing piston 6 has reached
the downward limit, the pressurizing cylinder 7 is driven to lift
the pressurizing piston 6 at low pressure in a step S22, the bottom
cover 9 is closed in a step S23 and the pressurizing piston 6 is
lifted to an upward end thereof in a step S24. Then, when a
normal-operation stop command is inputted to the control unit 100
in a step S25, the operation is stopped in a step S26. When the
normal-operation stop command is not inputted to the control unit
100 in the step S25, the process returns to the step S3 to reset
the number of filling times and then the filling step of S4 and
beyond is repeated.
[0049] In the preferred embodiment, first in the filling step, the
pressurizing piston 6 is operated in the first pressure stage to
press the pulverized biomass 11. Next in the reaction step, the
pressure of the pressurizing piston 6 is increased in
synchronization with feeding of the heating medium to the
cooling/heating medium path 4 to pressurize and heat the pulverized
biomass in the reaction container in the temperature and pressure
range to obtain the semi-carbonized or pre-semi carbonized solid
matter. After keeping the pressurized and heated state for a
prescribed period of time, the cooling/heating medium path 4 is
switched from the heating medium to the cooling medium to cool the
pulverized biomass while still maintaining the pressurized state,
thereby producing the shaped matter of biocokes 19. In this manner,
the hydraulic pressurization mechanism 8, the hydraulic ejection
mechanism 10 and the cooling/heating medium circulation mechanism
are controlled in conjunction by the control unit 100. Thus, it is
possible to produce biocokes in a short amount of time and
efficiently.
[0050] With the biocokes-producing apparatus in relation to the
preferred embodiment, it is possible to efficiently produce
biocokes having high hardness and high density which can be used as
an alternative to coal cokes. Further, the biocokes produced
according to the preferred embodiment can be used as a heat source,
a reducing agent or the like in a Cupola furnace or a blast furnace
for a casing manufacture or an iron manufacture, and can be used as
a burning fuel such as a power boiler fuel and slaked lime, and
also as a material utilizing the high compressive strength of the
biocoke.
* * * * *