Note: Descriptions are shown in the official language in which they were submitted.
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SOLID-LIQUID SEPARATOR
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus
that separates a solid-liquid mixture into solids and
liquids respectively independently.
2. Description of the Related Art
As the background art of this technical field, JP
07-313874 A and the national publication for the
international publication W02008/093707 disclose
techniques of utilizing the phase change of an organic
solvent to separate a solid-liquid mixture.
JP 07-313874 A discloses a configuration of an
apparatus that regenerates spent activated carbon by
using an organic solvent that is a liquid at ambient
temperature and atmospheric pressure, and distills the
used organic solvent for enhancing the purity, in order
to reuse the organic solvent for regenerating another
spent activated carbon.
The national publication for the international
publication W02008/093707 discloses a method for
liquefying a substance that is a gas at ambient
temperature and atmospheric pressure, and then mixing the
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liquefied substance with sewage sludge to deodorize the
sewage sludge.
SUMMARY OF THE INVENTION
JP 07-313874 A discloses a method for
regenerating activated carbon (adsorbent) by immersing
the spent activated carbon (spent adsorbent) in a large
amount of organic solvent, as well as a method for while
distilling the organic solvent that includes impurities
for reuse.
The national publication for the international
publication W02008/093707 discloses a method for
extracting malodorous components by immersing sewage
sludge in liquefied gas, and then separating the
malodorous components by causing the used liquefied gas
to change into a gas phase, as well as a method for
recovery of the liquefied gas.
According to JP 07-313874 A and the national
publication for the international publication
W02008/093707, a target substance is extracted by
immersing a solid-liquid mixture in an organic solvent,
and thus the extraction process requires a large amount
of organic solvent and increases processing cost. In
addition, a leakage of the organic solvent, when
occurring, increases risks.
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Therefore, the present invention provides a solid-
liquid separator that can reduce the amount of use of an
extraction medium such as an organic solvent that is
required for solid-liquid separation.
Certain exemplary embodiments can provide a solid-
liquid separator that separates a solid-liquid mixture into
solids and liquids by using a substance that is a gas at
ambient temperature and becomes a liquid at a saturated
vapor pressure or higher, the solid-liquid separator
comprising: a compressor configured to receive the substance
in a gaseous phase and to pressurize and heat the substance
into a pressurized gaseous state; a cooler configured to
liquefy the substance that has a high temperature and a high
pressure after being compressed; an accumulator configured
to store the liquefied substance; a valve configured to
regulate the flow rate of the liquefied substance at the
downstream of the accumulator; a sprayer configured to spray
the liquefied substance as droplets at the downstream of the
valve; a processing tank configured to contain the solid-
liquid mixture and including the sprayer at an upper portion
of the inside of the processing tank; a filter configured to
prevent the solid from flowing out of the processing tank;
and a vaporizer configured to vaporize the liquefied
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substance from a liquid mixture flowed out from the
processing tank, wherein an upper space of the inside of the
processing tank is filled with the vaporized substance in
the gaseous state.
Certain exemplary embodiments can provide a solid-
liquid separator that separates a solid-liquid mixture into
solids and liquids by using a substance that is a gas at
ambient temperature and becomes a liquid at a saturated
vapor pressure or higher, the solid-liquid separator
comprising: a cooler configured to liquefy the substance,
wherein, when the separator is in use, the substance is in a
in high-pressure gas state when received by the cooler; a
pump configured to feed the liquefied substance; an
accumulator configured to store the liquefied substance; a
valve configured to regulate the flow rate of the liquefied
substance at the downstream of the accumulator; a sprayer
configured to spray the liquefied substance as droplets at
the downstream of the valve; a processing tank configured to
contain the solid-liquid mixture and including the sprayer
at an upper portion of the inside of the processing tank; a
filter configured to prevent the solid from flowing out of
the processing tank; and a vaporizer configured to vaporize
the liquefied substance from a liquid mixture flowed out
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from the processing tank, wherein an upper space of the
inside of the processing tank is filled with the substance
in the gaseous state.
Further embodiments provide a solid-liquid separator
that separates a solid-liquid mixture into solids and
liquids respectively independently by using a substance that
is a gas at ambient temperature and becomes a liquid at a
saturated vapor pressure or higher. The solid-liquid
separator includes a compressor configured to compress the
substance, a cooler configured to liquefy the substance that
has a high temperature and a high pressure after being
compressed, an accumulator configured to store the liquefied
substance, a valve configured to regulate the flow rate of
the liquefied substance at the downstream of the
accumulator, a sprayer configured to spray the liquefied
substance as droplets at the downstream of the valve, a
processing tank configured to contain the mixture and
including the sprayer at an upper portion of the inside of
the processing tank, a filter configured to prevent the
solid from flowing out of the processing tank, and a
vaporizer configured to vaporize the substance from a liquid
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mixture flowed out from the processing tank. An upper space
of the inside of the processing tank is filled with the
substance in the gaseous state.
A further embodiment provides a solid-liquid
separator that separates a solid-liquid mixture into solids
and liquids respectively independently by using a substance
that is a gas at ambient temperature and becomes a liquid at
a saturated vapor pressure or higher. The solid-liquid
separator includes a cooler configured to liquefy the
substance that is a high-pressure gas, a pump configured to
feed the liquefied substance, an accumulator configured to
store the liquefied substance, a valve configured to
regulate the flow rate of the liquefied substance at the
downstream of the accumulator, a sprayer configured to spray
the liquefied substance as droplets at the downstream of the
valve, a processing tank configured to contain the solid-
liquid mixture and including the sprayer at an upper portion
of the inside of the processing tank, a filter configured to
prevent the solid from flowing out of the processing tank,
and a vaporizer configured to vaporize the substance from a
liquid mixture flowed out from the processing tank. An
upper space of the inside of the processing tank is filled
with the substance in the gaseous state.
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Furthermore, the solid-liquid separator according
to an embodiment of the present invention includes a heat
exchanger configured to use, as latent heat required to
vaporize the substance, latent heat generated when the
substance is liquefied.
Furthermore, in the solid-liquid separator
according to an embodiment of the present invention, a
heat exchanger that vaporizes the liquefied substance and
another heat exchanger that liquefies the gaseous
substance are connected in each other with a
refrigeration cycle using a refrigerant.
Furthermore, in the solid-liquid separator
according to an embodiment of the present invention, the
substance is dimethyl ether.
Furthermore, in the solid-liquid separator
according to an embodiment of the present invention, the
mixture comprises a spent adsorbent that has been used
for water treatment.
Furthermore, in the solid-liquid separator
according to an embodiment of the present invention, the
mixture comprises spent activated carbon that has been
used for water treatment.
Furthermore, in the solid-liquid separator
according to an embodiment of the present invention, the
sprayer comprises piping that is disposed horizontally,
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and is connected to an upstream flow passage with a
connecting pipe being rotatable at upper part of the
center of gravity of the piping. The piping has at least
two ejection outlets, the ejection outlets being provided
point-symmetrically with respect to the central axis of
the connecting pipe. The ejection outlets are provided
in a direction substantially perpendicular to the piping,
at positions between the vertically downward direction
and the horizontal direction, causing the sprayer to be
rotated by a fluid force of a fluid ejected from the
ejection outlets.
According to an embodiment of the present
invention, a solid-liquid separator can be provided which
uses a liquefied substance that has been liquefied by
pressurizing the substance that is a gas at ambient
temperature and atmospheric pressure to reach equal to or
higher than the saturated vapor pressure, so as to
separate a solid-liquid mixture. With the solid-liquid
separator, by spraying droplets of the liquefied
substance vertically from above onto the mixture in a
processing tank filled with the gas of the substance of
the saturated vapor pressure, the liquid within the
mixture is extracted by the generated droplets, making it
possible to reduce the amount of the liquefied substance
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in the processing tank, and to decrease running costs and
improve safety.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an exemplary schematic diagram
illustrating a solid-liquid separator according to an
embodiment of the present invention;
Fig. 2 is an exemplary internal structure of a
processing tank included in the solid-liquid separator
according to the embodiment of the present invention; and
Fig. 3 is another exemplary schematic diagram
illustrating a solid-liquid separator according to an
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to an embodiment of the present
invention, it is possible to separate a solid-liquid
mixture into solids and liquids respectively
independently. Specifically, the solid-liquid separator
according to an embodiment is applicable to various types
of solid-liquid separation, such as dehydration of a
sludge generated by water treatment, purification of oil-
contaminated soil, and dehydration and deoiling for
planktons.
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According to an embodiment of the present
invention, it is possible to desorb, with high
efficiency, adsorbed impurities from a spent adsorbent
that has been used for water treatment. Thus, an
activated carbon regeneration apparatus, as an example,
that regenerates spent activated carbon will be described
below as an embodiment of the present invention.
Examples of substances usable in the present embodiments
include ethylmethyl ether, formaldehyde, ketene, and
acetaldehyde. Dimethyl ether (hereinafter, referred to
as DME) having a boiling point of about -24 C and a
saturated vapor pressure at 24 C of about 0.58 MPa is
easy to handle, and thus can keep running cost low.
Therefore, DME will be described as an example in an
embodiment of the present invention. Embodiments of the
present invention will be described below with reference
to the accompanying drawings.
Examples of embodiments of the present invention
will now be described with reference to the accompanying
drawings.
(First Embodiment)
A configuration of an activated carbon
regeneration apparatus, to which the present invention is
applicable, will be described with reference to FIGS. 1
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and 2. Fig. 2 illustrates the internal structure of a
processing tank 2 illustrated in Fig. 1.
An embodiment illustrated in Fig. 1 provides a
configuration in which DME circulates in the apparatus
while undergoing a phase change, by using a compressor 5
and cooler 34. The inside of the flow passages and
devices is maintained at the saturated vapor pressure of
DME.
Gaseous DME is initially pressurized and heated
by the compressor 5. The pressurized gaseous DME is
cooled by a cooler 34, and then fed to a high
temperature-side flow passage 33 of a heat exchanger 7.
The gaseous DME in the high temperature-side flow passage
33 is cooled while the latent heat caused by liquefaction
is transmitted to a low temperature-side flow passage,
and the total amount of gaseous DME is liquefied and
discharged as liquefied DME. The liquefied DME is led to
a valve 11 via an accumulator 6. The flow rate of the
liquefied DME is adjusted at the valve 11, and the
liquefied DME is fed to the processing tank 2 filled with
the gaseous DME. An upper portion of the inside of the
processing tank 2 includes a sprayer 20 having a
structure that is horizontally rotatable about a vertical
axis. The liquefied DME is sprayed from the rotating
sprayer 20, as droplets, to the inside of the processing
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tank 2. A filter 45 is provided at the bottom of the
processing tank 2 to prevent a solid from flowing out, as
illustrated in Fig. 2. Spent activated carbon 50 to be
processed is contained above the filter 45. The droplets
ejected from the sprayer 20 fall by gravity, come into
contact with the spent activated carbon, and flow
downward while desorbing water and organic matters that
have adhered to or been adsorbed to the spent activated
carbon. Then, the droplets are discharged from a lower
portion of the processing tank 2 to be led to a valve 13.
The liquefied DME including impurities is
depressurized when passing through the valve 13,
partially vaporized to become a two-phase flow with a
lower temperature, and then led to the low temperature-
side flow passage of the heat exchanger 7. The DME
including impurities receives as much energy as the
latent heat of evaporation at the heat exchanger 7, and
is vaporized continuously. On the other hand, when the
amount of the impurities exceeds the solubility to DME
that has been concentrated and residing in the low
temperature-side flow passage, the impurities are
precipitated as deposit 31.
The vaporized DME, that is, gaseous DME, is again
fed from the compressor 5 to circulate. Thus, the
present embodiment is a phase change cycle of DME.
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Accordingly, in the present embodiment, causing DME to
circulate in this cycle can achieve an improved
desorption rate for the activated carbon, while
desorption is performed by contact with the droplets of
the liquefied DME at the inside of the processing tank 2,
making it possible to reduce the amount of use of DME,
leading to lower running cost and higher safety. Latent
heat of evaporation and latent heat of condensation,
exchanged at the heat exchanger 7, are substantially
equal in quantity and thus can be heat exchanged with a
slight temperature difference. Therefore, a large-scale
heat or cooling source that can handle the latent heat is
not required.
The principle of how to spray the droplets of the
liquefied DME into the processing tank 2 while filling
the inside of the processing tank 2 with the gaseous DME
will be described below. The upstream pressure can be
constantly maintained at the saturated vapor pressure or
higher with the valve 11. With the liquefied DME being
retained in the accumulator 6, DME discharged from the
sprayer 20 can constantly be kept in the state of liquid
even when the operation conditions of the compressor 5
vary, and thus, can be discharged as droplets. The
inside of the processing tank 2 is maintained at the
saturated vapor pressure by gaseous DME. Therefore, the
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ejected droplets are discharged as liquid from the bottom
of the processing tank 2 without being vaporized. The
degree of opening of the valve 13 provided at the
downstream of the processing tank 2 needs to be adjusted
so that the flow rate at the valve 13 can be equal to the
flow rate at the valve 11. If the flow rates differ, for
example, when the flow rate at the valve 13 is greater
than the flow rate at the valve 11, the pressure of the
inside of the processing tank 2 is lowered to cause DME
droplets to vaporize. As a result, contact of the spent
activated carbon with DME being in the form of liquid,
which is required to regenerate the activated carbon,
cannot be achieved. On the other hand, if the flow rate
at the valve 13 is less than the flow rate at the valve
11, the gaseous DME of the inside of the processing tank
2 is liquefied and stored. As a result, the amount of
DME to be circulating in the inside of the activated
carbon regeneration apparatus becomes insufficient.
The present invention can be implemented using a
fixed sprayer as the sprayer 20. More preferably,
however, using a rotatable sprayer improves uniformity in
the spraying amount of droplets to be applied to the
spent activated carbon, making it possible to reduce the
time needed to regenerate the activated carbon. The
inside of the processing tank 2 requires chemical
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resistance. Thus, although an external force such as a
motor can be used for the rotational driving force,
providing a sprayer with a structure to rotate using a
fluid force generated at the spraying may greatly reduce
the number of parts of the apparatus required for the
rotation, and may decrease the frequency of occurrence of
failures. In order to rotate the sprayer using the fluid
force, it may be sufficient to cause the center of
gravity of piping constituting the sprayer to be the axis
of rotation, and to provide ejection outlets in the
vicinity of at least both ends of the piping in the
direction of point-symmetrically with respect to the axis
of rotation. More specifically, it may be preferable to
provide the sprayer so that the ejection outlets may be
in the directions substantially perpendicular to the
piping, and more preferably the rejection outlets may be
in the directions between the vertically downward
direction and a substantially horizontal direction.
Furthermore, when the spent activated carbon is
taken out, closing the valve 11 and continuing the
operation of the compressor 5 may confine most of DME in
the cycle into the accumulator 6. As a result, after the
recovery of DME, closing the valve 13 and then opening
the processing tank 2 makes it possible to reduce the
amount of leakage of DME to the outside.
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The cooler 34 used for cooling DME is designed to
remove the amount of increased energy within a DME cycle
caused by the operation of the compressor 5, and thus,
may be a small-sized cooler. Note that the illustrated
pressure and temperature merely show qualitative changes,
and the present invention is not limited to these values
of pressure and temperature.
(Second Embodiment)
Fig. 3 illustrates another embodiment of the
present invention that uses a pump, not a compressor, for
circulation of DME, the pump being capable of reducing
initial and running costs. The phase change cycle of DME
in the present embodiment is substantially equal to that
in the embodiment illustrated in Fig. 1 except for what
is specifically described in the following. The second
embodiment is different from the first embodiment in that
a refrigeration cycle using a refrigerant for exchanging
latent heat of DME is connected.
On the side of DME cycle, liquefied DME is fed
from a pump 1, and then led to a valve 11 via an
accumulator 6. The liquefied DME that has passed through
the valve 11 is sprayed by a sprayer as droplets in the
inside of a processing tank 2 that is filled with gaseous
DME of the saturated vapor pressure, comes into contact
with the spent activated carbon, dissolves impurities
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contained in the spent activated carbon, and is
discharged from the bottom of the processing tank 2. The
discharged liquefied DME including the impurities passes
through a valve 13 as liquid, and is fed to the low
temperature-side flow passage of a heat exchanger 3. At
the heat exchanger 3, the fed liquefied DME receives
latent heat of evaporation from a refrigerant flowing in
a high temperature-side flow passage 36 and is vaporized,
while the impurities contained in the spent activated
carbon are separated as deposit 31. The vaporized DME,
that is, the gaseous DME, is led to the high temperature-
side flow passage of a heat exchanger 4. The vaporized
DME transmits latent heat of condensation to the
refrigerant flowing in a low temperature-side flow
passage 37 of the heat exchanger 4, and turns into the
liquefied DME to be fed from the pump 1 again for
circulation.
On the other hand, on the side of refrigeration
cycle where the refrigerant flows, a gaseous refrigerant
is heated and pressurized by a compressor 5, cooled at a
cooler 34, and then fed to the high temperature-side flow
passage 36 of the heat exchanger 3. At the heat
exchanger 3, the gaseous refrigerant is liquefied by
transmitting the latent heat of condensation of the
gaseous refrigerant to DME. The liquefied refrigerant is
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depressurized at an expansion valve 21, and thus,
partially vaporized to become a two-phase flow of the
refrigerant along with lowering a temperature of the
refrigerant. The refrigerant that has become the two-
phase flow is fed to the low temperature-side flow
passage 37 of the heat exchanger 4, and then, receives
latent heat of condensation from the gaseous DME in the
high temperature-side flow passage. As a result, the
refrigerant in the two-phase flow cycle is all vaporized.
The vaporized refrigerant is again compressed at the
compressor 5 to be circulated.
Therefore, according to the present embodiment, a
phase change cycle of DME can be achieved at low cost, by
using an existent refrigerant, a compressor for the
refrigerant, and an inexpensive pump for DME, without
using the compressor for the gaseous DME.
