Note: Descriptions are shown in the official language in which they were submitted.
CA 02677589 2011-08-19
APPARATUS AND METHOD FOR DRY DISTILLATION OF OIL SHALE
BACKGROUND OF THE INVENTION
[0001 ] Field of the Invention
[0002] The invention relates to an apparatus and a method for dry distillation
of oil shale.
[0003] Description of the Related Art
[0004] Oil shale are widely distributed throughout the world and become of
economic interest
because of the large amounts of oil which can be obtained from them.
Conventional apparatuses for
dry distillation of oil shale comprise a petrosix retort, an alberta taciuk
processor (ATP) retort and
so on. However, there are several problems with these apparatuses: they have
complex structure,
inconvenient operation, high investigation cost, low oil recovering rates, and
poor resource
utilization rates. Moreover, the same problems as above are encountered with
conventional methods
for dry distillation of oil shale.
SUMMARY OF THE INVENTION
[0004A] In one aspect of the present invention, there is provided a method for
dry distillation of oil
shale, comprising inducing oil shale from the top of a gas retort, a vibration
bed of nine layers being
disposed in the gas retort, the layers of the vibration bed being obliquely-
disposed and linked end to
end to form a Z-shaped structure, each layer being covered with a screen plate
having screen holes,
the vibration bed kept in a state of vibration; dispersing the oil shale into
Z-shaped, flat and loose
material flow via the vibration bed, a first portion of the oil shale having
granularity less than the
screen holes, the first portion dropping via the screen holes and forming a
dilute phase layer with oil
shale blown up from the next layer, a second portion of the oil shale having
granularity greater than
the screen holes, the second portion forming a loose material layer that moves
along the screen plate
and drops onto the next screen plate; leading hot recycle gas at a temperature
of 700 C into the gas
retort from the bottom of the fourth, the fifth, and the sixth layer of the
vibration bed, where the
layers of the vibration bed being counted from the top to bottom, thereby
forming vertical airflow
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and horizontal airflow; mixing the vertical airflow and the horizontal airflow
with the material flow
of the oil shale to dry distill the oil shale to obtain semi coke; leading
cold recycle gas from the
bottom of the gas retort and cooling the semi coke to 250 C; dropping the semi
coke into a water
seal tank, cooling the semi coke to 80 C and discharging the semi coke via a
discharging system
disposed at the bottom of the gas retort;
discharging dry distillation gas produced in the process of dry distillation
and recycle gas from the
top of the gas retort and transmitting them to a heating furnace after
removing dust and recovering
oil; and heating the dry distillation gas to 700 C via a heating furnace and
transferring the dry
distillation gas to the gas retort.
[0004B] In another aspect of the present invention, there is provided An
apparatus for dry
distillation of oil shale, comprising: a vibration bed of nine layers; a gas
retort; a feeding system;
a feeding hole; nine screen plates; three hot recycle gas inlets; a cold
recycle gas inlet; a water seal
tank; a discharging system; and a gas outlet; wherein the feeding system and
the feeding hole are
disposed at the top of the gas retort; the screen plates are disposed on the
layers of the vibration bed;
the nine layers of the vibration bed are obliquely disposed in the gas retort
to form a Z-shaped
structure; the three hot recycle gas inlets are disposed on the wall of the
gas retort and respectively
below the fourth layer, the fifth layer and the sixth layer of the vibration
bed; the cold recycle gas
inlet is disposed below the ninth layer of the vibration bed; the water seal
tank and the discharging
system are disposed at the bottom of the gas retort; and the gas outlet is
disposed at the top of the
gas retort.
[0005] In view of the above-described problems, it is one objective of the
invention to provide a
method for dry distillation of oil shale that features a simple structure,
convenient operation, low
investigation cost, a high oil recovering rate, and a high resource
utilization rate.
[0006] It is another objective of the invention to provide an apparatus for
dry distillation of oil shale
that features a simple structure, convenient operation, low investigation
cost, a high oil recovering
rate, and a high resource utilization rate.
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[0007] To achieve the above objective, in accordance with one embodiment of
the invention,
provided is a method for dry distillation of oil shale, comprising inducing
oil shale from the top of a
gas retort and dispersing the oil shale into Z-shaped, flat and loose material
flow via a vibration bed
with multiple layers, part of the oil shale having granularity less than
screen holes dropping via the
screen holes and forming a dilute
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phase layer with oil shale blown up from the next layer, the rest of the oil
shale having
granularity greater than the screen holes forming a loose material layer that
moves along
a screen plate and drops on the next screen plate, leading hot recycle gas at
a temperature
of 700 C into the gas retort from the bottom of the fourth, the fifth, and the
sixth layer of
the vibration bed whereby forming vertical airflow and horizontal airflow,
mixing the
vertical airflow and the horizontal airflow with the oil shale whereby
generating mixing
flow of the oil shale and the gas, leading cold recycle gas from the bottom of
the gas
retort and cooling semi coke that has been dry distilled to 250 C, dropping
the semi coke
into a water seal tank, cooling it to 80 C and discharging it via a
discharging system
disposed at the bottom of the gas retort, discharging dry distillation gas and
recycle gas
from the top of the gas retort and transmitting them to a heating furnace
after removing
dust and recovering oil, and heating the dry distillation gas to 700 C via a
heating furnace
and transferring it to the gas retort.
[0008] In a class of this embodiment, granularity of the oil shale is below 12
mm
[0009] In a class of this embodiment, granularity of the oil shale is below 6
mm.
[0010] In a class of this embodiment, a height of each of the third layer, the
fifth layer,
and the sixth layer of the vibration bed is 4.5 m - 5 m.
[0011 ] In a class of this embodiment, the third layer, the fifth layer, and
the sixth layer of
the vibration bed are dry distillation sections.
[0012] In a class of this embodiment, moving speeds of oil shale on different
layers are
varied by adjusting a motor frequency of each layer of the vibration bed.
[0013] In a class of this embodiment, time of keeping materials in the gas
retort is varied
by adjusting a motor frequency of each layer of the vibration bed.
[0014] In accordance with another embodiment of the invention, provided is an
apparatus
for dry distillation of oil shale, comprising a vibration bed with multiple
layers, a gas
retort, a feeding system, a feeding hole, a screen plate, a water seal tank, a
discharging
system, and a gas outlet, wherein the feeding system and the feeding hole are
disposed at
the top of the gas retort, the screen plate is disposed on the vibration bed,
the layers of the
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vibration bed are obliquely disposed in the gas retort, the number of layers
of the
vibration bed is nine, three hot recycle gas inlets are disposed on the wall
of the gas retort
and respectively below the fourth layer, the fifth layer and the sixth layer
of the vibration
bed, a cold recycle gas inlet is disposed below the ninth layer of the
vibration bed, the
water seal tank and the discharging system are disposed at the bottom of the
gas retort,
and the gas outlet is disposed at the top of the gas retort.
[0015] In a class of this embodiment, the obliquely disposed layers of the
vibration bed
form a Z-shaped structure.
[0016] A key point of the invention is that the vibration bed with nine layers
is used to
transport oil shale, and fully contacted with the hot recycle gas during the
transportation
process whereby facilitating dry distillation. To implement the dry
distillation processing,
the following techniques are used: firstly, movement of the oil shale is in
the manner of
vibration caused by gravity thereof and driving force applied by vibration. A
Z-shaped
material flow is formed in the gas retort. A height of the gas retort is
approximately 17 in,
and a travel distance of the oil shale is approximately 36 in. Secondly, a
mixing flow
technique is used, contact between hot gas and the oil shale is horizontal and
vertical,
contact between the oil shale and the screen plate exists or does not exist,
and the
material layer is always loose, which ensures hot carriers are fully contacted
with the oil
shale. Thirdly, hot gas are induced from three layers of the vibration bed,
which ensures
temperature in the gas retort is above 550 C and a height of a dry
distillation layer is
between 4.5 in and 5 in, and guarantees safety of the dry distillation
process. Fourthly,
moving speeds of oil shale on different layers and time of keeping materials
in the gas
retort are varied by adjusting a motor frequency of each layer of the
vibration bed, which
makes operation convenient. Fifthly, a full recycle process of hot gas is
used, heating of
gas is performed outside the gas retort and no heating process occurs therein,
no air enters
therein, and heat needed by the dry distillation process is completely
dependent on the
hot recycle gas, which improves a calorific value of the gas and that of the
semi coke.
Sixthly, cold recycle gas is induced from the bottom of the gas retort and
reduces
temperature of the semi coke that is dry distillated. Finally, a water seal
scraping plate is
disposed at the bottom of the gas retort to facilitate coke discharging, which
prevents gas
from leaking and protects the environment.
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[0017] Advantages of the invention comprise:
[0018] 1. The invention features simple structure and convenient operation. A
traditional
gas retort covers an area above 1000 m2, and the gas retort of the invention
only covers
no more than 100 m2. The traditional gas retort is complex in structure and
inconvenient
for operation. The invention facilitates variation of moving speeds of oil
shale by
adjusting frequencies of motors, which makes the invention simple in structure
and
convenient for operation;
[0019] 2. The invention features a high oil recovering rate and a high gas
calorific value.
Since a full recycle process of gas is used, a special mixing flow is formed
by vertical
airflow, horizontal airflow, forward flow, and reverse flow between the oil
shale and the
hot gas, and features no air, no heating reaction, a high oil recovering rate
above 90%,
and a gas calorific value above 4000 kcal/kg;
[0020] 3. The invention features low investigation cost and a high efficiency,
The
conventional gas retort normally spends 1.5 billion US dollars and seven
years, and the
invention only spends no more than 100 million US dollars;
[0021] 4. The invention features a high resource utilization rate of 100%, oil
shale having
granularity less than 12 mm can be used as raw materials, and new exploited
oil shale can
be broken into oil shale having granularity less than 6 mm for dry
distillation; and
[0022] 5. A water seal scraping plate is disposed at the bottom of the gas
retort to
facilitate coke discharging, which prevents gas from leaking and protects the
environment.
[0023] In a class of this embodiment, the step of applying force on the
polycrystalline
silicon rods so that the polycrystalline silicon rods are detached from the
base plate and
fall into the cavity comprises applying force on the polycrystalline silicon
rods via a
contact, passing a wall of the harvest equipment by the contact, applying
force on the
polycrystalline silicon rods so that they are detached from the base plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Detailed description of the invention will be given below with
reference to
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accompanying drawings, in which:
[0025] FIG 1 is a schematic view of an apparatus for dry distillation of oil
shale of an
exemplary embodiment of the invention; and
[0026] FIG 2 is a cross-sectional view of an apparatus for dry distillation of
oil shale of
an exemplary embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] As shown in FIGS. 1 and 2, a method for dry distillation of oil shale
of the
invention comprises inducing oil shale from a bucket 2 at the top of a gas
retort 4 and
dispersing the oil shale into Z-shaped, flat and loose material flow via a
vibration bed 3
with multiple layers, part of the oil shale having granularity less than
screen holes
dropping via the screen holes and forming a dilute phase layer with oil shale
blown up
from the next layer, the rest of the oil shale having granularity greater than
the screen
holes forming a loose material layer that moves along a screen plate and drops
on the
next screen plate, leading hot recycle gas at a temperature of 700 C into the
gas retort 4
from the bottom of the fourth, the fifth, and the sixth layer of the vibration
bed 3 via hot
recycle gas inlets 5, 10 and 11 whereby forming vertical airflow and
horizontal airflow,
mixing the vertical airflow and the horizontal airflow with the oil shale
whereby
generating mixing flow of the oil shale and the gas, leading cold recycle gas
from the
bottom of the gas retort 4 and cooling semi coke that has been dry distilled
to 250 C,
dropping the semi coke into a water seal tank 7, cooling it to 80 C and
discharging it via
a discharging system 8 disposed at the bottom of the gas retort 3, discharging
dry
distillation gas and recycle gas from the top of the gas retort 4, mixing the
oil shale with
the gas, separating the oil shale from the gas, remixing the oil shale with
gas, and
re-separating the oil shale from the gas whereby uniformly dry distilling the
oil shale,
cooling the oil shale via the cold gas induced from the bottom of the gas
retort 4 and the
and water seal tank 7, dropping the oil shale into the discharging system 8,
discharging
the oil shale from the bottom of the gas retort 4, discharging dry
distillation gas and
recycle gas from the top of the gas retort 4 with the recycle gas,
transmitting them to a
heating furnace after removing dust and recovering oil, and heating the dry
distillation
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gas to 700 C via a heating furnace and transferring it to the gas retort.
[0028] In this embodiment, a height of each of the third layer, the fifth
layer, and the sixth layer of
the vibration bed 3 is 4.5 m - 5 m.
[0029] In this embodiment, granularity of the oil shale is below 12 mm or 6
mm.
[0030] The third layer, the fifth layer, and the sixth layer of the vibration
bed 3 are dry distillation
sections.
[0031] Moving speeds of oil shale on different layers and time of keeping
materials in the gas retort
3 are varied by adjusting a motor frequency of each layer of the vibration
bed.
[0032] As shown in FIGS. 1 and 2, an apparatus for dry distillation of oil
shale of the invention
comprises a vibration bed 3 with multiple layers, a gas retort 4, a feeding
system 1, a feeding hole, a
screen plate, a water seal tank 7, a discharging system 8, and a gas outlet
12.
[0033] The feeding system 1 and the feeding hole are disposed at the top of
the gas retort 4.
[0034] The screen plate is disposed on the vibration bed 3.
[0035] The layers of the vibration bed 3 are obliquely disposed in the gas
retort 4.
[0036] The number of layers of the vibration bed 3 is nine, and three hot
recycle gas inlets 5, 10 and
11 are disposed on the wall of the gas retort 4 and respectively below the
fourth layer, the fifth layer
and the sixth layer of the vibration bed 3.
[0037] A cold recycle gas inlet 6 is disposed below the ninth layer of the
vibration bed 3.
[0038] The water seal tank 7 and the discharging system 8 are disposed at the
bottom of the gas
retort 4.
[0039] The gas outlet 12 is disposed at the top of the gas retort 4.
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