BACKGROUND
This invention relates generally to conveying apparatuses, systems and
conveyance methodologies. More particularly, this invention relates to conveying
apparatuses, systems and conveyance methodologies for pneumatic conveyance of
solid powders such as carbonaceous fuel powders into gasifiers for gasification.
Gasification is a process that enables the conversion of carbonaceous
fuels, such as coal into a combustible gas, such as coal gas or synthesis gas.
Generally, gasification processes include feeding carbonaceous fuels into gasifiers
along with a controlled andfor limited amount of oxygen and other steams. A stable
and controllable flow of such carbonaceous fuels into gasifiers is beneficial for
obtaining desirable gasification performance.
Pneumatic conveyance technologies are often used to convey
carbonaceous fuels into gasifiers. In conventional conveying systems employing
pneumatic conveyance technologies, such conveying systems typically comprise
storage tanks, feeding pipelines in fluid communication with the storage tanks, and a
conveying pipeline disposed between and in fluid communication with the storage
tanks and the gasifiers.
The storage tanks receive carbonaceous fuels and carrier gases through
the feeding pipelines. With the introduction of the carrier gases into the storage tanks,
the pressures of the storage tanks increase to desired levels, which are higher lhan
pressures in the gasifiers so as to generate pressure differences between such storage
tanks and gasifiers. A gas solid mixture then may be conveyed from the storage tanks
into the gasifiers through the conveying pipeline in virtue of the pressure differences.
However, in such conventional conveying systems, the flow of the
carbonaceous fuels within the conveying pipeline may have an unstable flow. For
example, in a plug flow situation results in flow rates of the carbonaceous fuels within
the conveying pipeline that is not uniform and thus become unstable for introduction
of the carbonaceous fuels into the gasifiers. This may generate temperature
fluctuations in the gasifiers, which is disadvantageous to the performance and service
life of the gasifiers.
Therefore, there is a need for a new and improved conveying
apparatuses, systems and methods for pneumatic conveyance of solid powders such as
carbonaceous fuel powders.
BRIEF DESCRIPTION
A conveying apparatus for pneumatic conveyance of a solid powder is
provided in accordance with one embodiment of the invention. The conveying
apparatus comprises a conveying pipeline and a supplementary gas pipeline extending
into the conveying pipeline. The conveying pipeline defines an inlet and an outlet, .
and comprises an expanding portion defining the inlet, a shrinking portion defining
the outlet, and an intermediate portion disposed between and in fluid communication
with the expanding portion and the shrinking porhon.
A conveying system for pneumatic conveyance of a solid powder is
provided in accordance with another embodiment of the invention. The conveying
system comprises a storage tank configured to receive a solid powder, a carrier gas
pipeline in fluid communication with the storage tank, a conveying pipeline, and a
supplementary gas pipeline in fluid communication with the conveying pipeline. The
conveying pipeline is disposed downstream of and in fluid communication with the
storage .tank, and comprises an expanding porhon defining an inlet, a shrinking
portion defining an outlet, and an intermediate portion disposed between and in fluid
communication with the expanding portion and the shrinking portion.
An embodiment of the invention further provides a conveying method
for pneumatic conveyance of a solid powder. The conveying method comprises
feeding a solid powder into a storage tank, introducing a carrier gas into the storage
tank to mix with the solid powder to form a gas solid mixture in the storage tank,
conveying the gas solid mixture from the storage tank into a conveying apparatus via
an inlet of the conveying apparatus for adjustment, and conveying the adjusted gas
solid mixture out of the conveying apparatus via an outlet of the shrinking portion.
The conveying apparatus comprises a conveying pipeline and a supplementarq. gas
pipeline in fluid communication with the conveying pipeline. The conveying pipeline
comprises an expanding portion defining the inlet, a shnnking portion defining the
outlet, and an intermed~atep ortion disposed between and in fluid communication with
the expanding portion and the shrinking porhon.
BRIEF DESCRIPTION OF THE DRAWINGS
' The above and other aspects, features, and advantages of the pre.sent
disclosure will become more apparent in light of the following detailed description
when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic diagram of a conveying system in accordance
with one embodiment of the invention; and
FIG. 2 is a schematic flow chart of operation of the conveying system
in accordance with one embodiment of the invention.
DETAILED DESCRIPTION OF THE DISCLOSURE
Embodiments of the present disclosure will be described hereinbelow
with reference to the accompanying drawings. In the following description, wellknown
functions or constructions are not described in detail to avoid,obscuring the
disclosure in unnecessary detail.
FIG. 1 illustrates a schematic diagram of a conveying system 10 for
conveying a solid powder, such as one or more carbonaceous fuels into a device 100
for processing in accordance with one embodiment of the invention. In non-limiting
examples, the conveying system 10 is configured for pneumatic conveyance of the
solid powder into the device 100, where the device 100 may be a gasifier for
gasification of the solid carbonaceous fuels. In one example, the carbonaceous fuels
include coal. .In other non-limiting examples, the carbonaceous fuels may include
bituminous, soot, biomass, petroleum coke or combinations thereof.
As illustrated in FIG. 1, the conveying system 10 comprises a feeder
1 1, a storage tank 12, a carrier gas pipeline 13, a feeding pipeline 14, and a conveying
apparatus 15. In some examples, the feeder 11 is configured to feed a solid powder
16 with desired size distribution into the storage tank 12.. In one non-limiting
example, the feeder 11 may comprise a screw feeder.
The storage tank 12 is in fluid communication with the feeder 11 and
configured to receive the solid powder 16 through a conveyance, such as a pipeline
(not shown) via the feeder 11. In other examples, a pump (not shown) may be
employed to introduce the solid powder 16 into the storage tank 12. For some
arrangements, the storage tank 12 may not limit to any particular shapes. In nonlimiting
examples, the storage tank 12 may comprise an upper portion (not shown)
disposed downstream of and in fluid communication with the feeder 11, and a lower
portion (not shown) connected with the upper portion. In one example, the upper
porhon of the storage 12 may have a cylindrical shape and the lower portion of the
storage 12 may have a conical shape.
The carrier gas pipeline 13 is disposed on the storage tank 12 and
configured to introduce a carrier gas 17 into the storage tank 12 to mix with the solid
powder 16 to form a gas solid mixture. Non-limiting examples of the carrier gas 17
include carbon dioxide, inert gas such as nitrogen or other suitable gases. Although
one carrier gas pipeline 13 is shown in the illustrated embodiment, more than one
carrier gas pipeline 13 may nonetheless be employed.
With the introduction of the carrier gas 17 into the storage tank 12, the
pressures of the storage tank 12 may increase to desired levels. In non-limiting
examples, the desired pressure in the storage tank 12 may be higher than a pressure in
the device 100 so as to generate a pressure difference between the storage tank 12 and
the device 100. In one example, the desired pressure in the storage tank 12 is about 3
Mega Pascals (Mpa).
The feeding pipeline 14 is disposed between and in fluid
communication with the storage tank 12 and the device 100 respectively so as to
convey the gas solid mixture from the storage tank 12 into the device 100 for
processing, for example, for gasification. In non-limiting examples, the fcding
pipeline 14 may have a cylindrical shape.
In the illustrated example, the feeding pipeline 14 comprises E first
feeding pipeline 18 and a second feeding pipeline 19. The first feeding pipeline 18 is
disposed between the storage tank 12 and the conveying apparatus 15, and is
configured to convey the gas solid mixture from the storage tank 12 into the
conveying apparatus 15. The second feeding pipeline 19 is dsposed betweex the
conveying apparatus 15 and the device 100, and is configured to convey the gas solid
mixture from the conveying apparatus 15 into the device 100. In certain applicafions,
the second feehng pipeline 19 may or may not be employed.
In some applications, the flow of the gas solid mixture may be in an
unstable flow in the first conveying pipeline 18, for example, in a plug flow res~lting
in the flow rates of the solid powder in the first conveying pipeline 18 may be not
uniform. For the illustrated arrangement, the conveying apparatus 15 is disposed
between and in fluid communication with the first and second conveying pipelines 18,
19, and is configured to stabilize the flow of the gas solid mixture. As a result, after
adjustment by the conveying apparatus 15, the flow rates of the solid powder may be
uniform and the gas solid mixture may be stably introduced into the second conveying
pipeline 19 for stable introduction into the device 100.
As depicted in HG. 1, the conveying apparatus 15 comprise a
conveying pipeline 20 and a supplementary gas pipeline 21 coupled to the conveying
pipeline 20. For the illustrated arrangement, the conveying pipeline 20 is disposed
downstream of the storage tank 12, and defines an inlet 22 and an outlet 23 to t,e in
fluid communication with the first and second feeding pipelines 18, 19 respecti7ely
for the gas solid mixture from the first feeding pipeline 18 passing through the
conveying pipeline 20 for introduction into the device 100.
In the illustrated example, the conveying pipeline 20 comprises an
expanding porhon 24, a shrinking portion 25, and an intermediate portion 26 disposed
between and connected to the expanding pofion 24 and the shrinking portion 25. The
expanding portion 24 defines the inlet 22 and the shrinking portion 25 defines the
inlet 23.
In some examples, the expanding portion 24 and the shrinking partion
25 may have a shape of frustum of a cone. The intermediate portion 26 may have a
cylindrical shape. Alternatively, the expanding portion 24, the shrinking portion 25, .
and the intermediate porhon 26 may have other shapes, such as polygon shapes.
In non-limiting examples, as used herein, the term "expanding" rr-eans
diameters of the expanding portion 24 may increase along a direction from the inlet
22 to the outlet 23 or a flow direction of the gas solid mixture in the conveying
pipeline 20. The term "shrinking" means diameters of the shrinking portion 25 may
decrease along the direction from the inlet 22 to the outlet 23. In some examples, the
diameters of at least a section of the expanding portion 24 may be larger than
diameters of the first feeding pipeline 18. The diameters of at least a section o€ the
shrinking portion 25 may be larger than diameters of the second feeding pipeline 19.
In one non-limiting example, diameters of the intermediate portion 26 may be larger
than the diameters of at least a section of at least one of the expanding portion 24 and
shrinking portion 25. The diameters of the first feeding pipeline 18 are similar to the
diameters of the second feeding pipeline 19.
In some applications, the supplementary gas pipeline 21 is configured
to introduce a supplementary gas 27 into the conveying pipeline 20 via an inlet 28
thereof for facilitating conveyance of the solid powder. In the illustrated example, the
supplementary gas pipeline 21 is disposed on the intermediate portion 26 and exknds
into the conveying pipeline 20 so that an outlet 29 thereof extends or is exposed into a
space defined by the shnking pofion 25. In one example, at least a portion o i the
supplementary gas pipeline 21 extends towards the outlet 23 of the conveying pipeline
20 so that the outlet 29 is near the outlet 23. In other examples, the supplementary
gas pipeline 21 may be disposed on the expanding portion 24 or the shrinking portion
25 and extend towards the outlet 23.
Thus, during introduction of the gas solid mixture from the first
feeding pipeline 18 into the conveying pipeline 20 via the inlet 22, in the expariding
portion 24, a velocity of the gas in the gas solid mixture from the feeding pipeline 18
may be reduced and a velocity of the solid in the gas solid mixture may be similar to a
velocity of the gas solid mixture in the feedng pipeline 18, so that at least a portion of
the gas is separated from at least a portion of the solid in the gas solid mixture due to
space expanding of the expanding portion 24. Accordingly, the flow pattern, for
example an unstable flow pattern of the gas solid mixture in the feeding pipeline 18
may be changed or adjusted by the expanding porhon 24.
In some embodiments, the intermediate portion 26 may act as a buffer
portion so that the gas continues to be separated from solid powder so as to fudher
change the flow pattern of the gas solid mixture. In the shrinking portion 25, due to
space limitation thereof, a velocity of the separated gas may increase towards the
outlet 23 and remix with the solid powder for carrying the solid powder. In addition,
the supplementary gas pipeline 21 also introduces the supplementary gas 27 into the
shrinking porhon 25 via the outlet 29 to further increase the velocity of the gas for
remixing with the solid powder. As a result, with the adjustment by the conveying
apparatus 15, the gas and the solid powder may be mixed uniformly to form a gas
solid mixture having a stable flow pattern.
Thus, the gas solid mixture from the conveying apparatus 15 may be
introduced into the second feeding pipeline 19 uniformly and stably via the outlet 23
for introduction into the device 100. Compared to the previous flow pattern, for
example, the plug flow of the gas solid mixture in the first feeding pipeline 18, due to
adjustment by the conveying apparatus 15, the flow rates of the solid powder may
become uniform and stable, and thus the flow of the gas solid mixture from the
conveying apparatus 15 may also become uniform and stable. In some applications,
similar to the carrier gas 17, non-limiting examples of the supplementary gas 27 also
include carbon dioxide, inert gas such as nitrogen or other suitable gases.
It should be noted that the arrangement in FIG. 1 is merely illustrative.
In the illustrated example, one supplementary gas pipeline 21 is employed.
Alternatively, more than one supplementary gas pipeline may be employed. In certain
applications, an additional gas pipeline (not shown) may be disposed on the first
feeding pipeline 18 for introducing a gas to adjust the concentration of the solid
powder in the first feeding pipeline 18. Although integrated together to act as a single
element in the illustrated example, the expanding portion 24, the shrinking portion 25
and the intermediate portion 26 may be provided separately and assembled together.
In certain applications, the carrier gas 17 and the supplementary gas 27
may be provided from one gas source or from more than one gas sources. In addition,
for the illustrated arrangement, the feeding pipeline 14 andor the conveying pipeline
20 are disposed above the device 100 and upright relative to a horizontal direction
(not shown). In other applications, longitudinal axis of the feeding pipeline 14 andor
the conveying pipeline 20 may have an angle in a range of from about 70" to about
90" relative to the horizontal direction.
FIG. 2 illustrates a schematic flow chart 30 of operation of the
conveying system 10 in accordance with one embodiment of the invention. As
illustrated in FIG. 2, during conveyance, in step 3 1, a solid powder 16 having desired
size distribution is introduced into the storage tank 12 from a solid powder source (not
shown). In step 32, a carrier gas 17 is introduced into the storage tank 12 through the
carrier gas pipeline 13 to form the gas solid mixture and increase the pressure in the
storage tank 12. For some arrangements, the sequence for performing the steps 31
and 32 may vary. The step 3 1 may be performed prior to, simultaneous with or after
the step 32.
With the introduction of the canier gas 17 into the storage tank 12, the
pressure in the storage tank 12 increases to a desired pressure. In one example, the
desired pressure is higher than the pressure in the device 100 so that a pressure
difference is produced to push the gas solid mixture from the storage tank 12 towards
the device 100 and to offset the pressure drop during the conveyance of the gas solid
mixture from the storage tank 12 to the device 100.
In step 33, after the pressure in the storage tank 12 increases to a
desired pressure, the gas solid mixture is introduced into the conveying apparatus 15
for adjustment through the first feeding pipeline 18 connected the conveying
apparatus 15 and the storage tank 12. In this step, the gas solid mixture from the first
feeding pipeline 18 passes through the expanding portion 24, the intermediate porlion
26 and the shrinking portion 25 of the conveying pipeline 20 in turn. Meanwhile, the
supplementary gas 27 is introduced into the shrinking portion 25 for facilitating
conveyance of the solid powder.
In some applications, the velocity of the supplementary gas 27 for
introduction into the shrinking pofion 25 may be higher than the velocity of the
carrier gas 17 in the conveying pipeline 20. In non-limiting examples, the ratio of a
flux of the supplementary gas 27 in the supplementary gas pipeline 21 to a flux of the
camer gas 17 in the first feeding pipeline 18 may be in a range of about 0.2 to about 1.
The velocity of the gas in the second feeding pipeline 19 may be about in a range of
from about 20ds to about 40mIs.
As a result, due to adjustment of the conveying apparatus 15 to the gas
solid mixture from the first feeding pipeline 18,. the flow rates of the solid powder
become uniform and the gas and the solid may be mixed uniformly resulting in the
flow of the adjusted gas solid mixture from the conveying apparatus 15 become stable.
In step 34, the adjusted gas solid mixture from the conveying apparatus 15 is
introduced into the gasifier 100 for gasification.
In embodiments of the invention, the conveying system 10 employs the
conveying apparatus 15 to stabilize the gas solid mixture from the feeding pipeline 14.
The conveying apparatus 15 employs a supplementary gas pipeline 21 and a
conveying pipeline 30 including the expanding portion 24, the intermediate portion 26
and the shrinking portion 25 to adjust the flow of the gas solid mixture, so that the
flow rates of the solid powder become uniform and stable, and the flow of the. gas
solid mixture from the conveying apparatus 15 also become uniform and stable for
conveyance into the device 100. This improves the performance arid life time of the
device 100, for example, the gasifier. Compared to the conventional conveying
systems, the arrangements of the invention may have a relatively simple configuration
and may be used to retrofit the conventional conveying system in a lower cost.
While the disclosure has been illustrated and described in typical
embodiments, it is not intended to be limited to the details shown, since various
modifications and substitutions can be made without departing in any way from the
spirit of the present disclosure. As such, further modifications and equivalents of the
disclosure herein disclosed may occur to persons skilled in the art using no more than
routine experimentation, and all such modifications and equivalents are believed to be
within the spirit and scope of the disclosure as defined, by the following claims.

WE CLAIM:
1. A conveying apparatus for pneumatic conveyance of a solid powder,
comprising:
a conveying pipeline defining an inlet and an outlet, and the conveying
pipeline comprising:
an expanding portion defining the inlet;
a shrinking portion defining the outlet; and
an intermediate portion disposed between and in fluid
communication with the expanding portion and the shrinking portion; and
a supplementary gas pipeline extending into the conveying pipelin?.
2. The conveying apparatus of claim 1, wherein diameters of the
expanding portion increase along a direction from the inlet to the outlet, and where
diameters of the shrinking portion decrease along the direction from the inlet to the
outlet.
3. The conveying apparatus of claim 2, wherein diameters of at least a
. section ,of the intermediate portion is larger than diameters of at least a section of at
least one of the expanding portion and the shrinking portion.
4. The conveying apparatus of claim 1, wherein the supplementary gas
pipeline is disposed on the intermediate portion, and wherein at least a portion of the
supplementary gas pipeline is disposed within the conveying apparatus and extends
towards the outlet of the conveying pipeline.
5. The conveying apparatus of claim 1, wherein the supplementary gas
pipeline defines an outlet disposed within the shrinking pofion.
6. The conveying apparatus of claim 1, wherein a longitudinal axis of the
conveying pipeline has an angle in a range of from about 70°C to about 90°C relative
to a horizontal direction.
7. The conveying apparatus of claim 1, wherein the expanding portion,
the shrinking portion and the intermediate porhon are integral with each other.
8. A conveying system for pneumatic conveyance of a solid powder,
comprising:
a storage tank configured to receive a solid powder;
a carrier gas pipeline in fluid communication with the storage tank;
a conveying pipeline disposed downstream of and in fluid
communication with the storage tank, and the conveying pipeline comprising:
an expanding portion defining an inlet;
a shrinking poaon defining an outlet; and
an intermediate portion disposed between and in fluid
communication with the expanding portion and the shrinking portion; and
a supplementary gas pipeline in fluid communication with the
conveying pipeline.
9. The conveying system of claim 8, wherein diameters of the expanding
porhon increase along a direction from the inlet to the outlet, and where diameters of .
the shrinking portion decrease along the direction from the inlet to the outlet.
10. The conveying system of claim 8, wherein the supplementary gas
pipeline is disposed on the intermediate portion, and wherein at least a portion of the
supplementary gas pipeline is disposed within the conveying apparatus and extends
towards the outlet of the conveying pipeline.
11. The conveying system of claim 8, wherein the supplementary gas
pipeline extends into the conveying pipeline and defines an outlet disposed within the
shrinking portion.
12. The conveying system of claim 8, further comprising a first feeding
pipeline disposed between and in fluid communication with the storage tank and the
conveying pipeline via the inlet of the expanding portion.
13. The conveying system of claim 12, further comprising a second
feeding pipeline disposed downstream of and in fluid communication with the
conveying pipeline via the outlet of the shrinking portion.
14. The conveying system of claim 13, wherein diameters of at least a
section of the expanding portion are larger than diameters of the first feeding pipeline,
and wherein diameters of at least a section of the shrinking portion are larger than
diameters of the second feeding pipeline.
15. The conveying system of claim 13, wherein the first and second
feeding pipelines and the conveying pipeline are disposed upright relative to a
horizontal direction.
16. A conveying method for pneumatic conveyance of a solid powder,
comprising:
feeding a solid powder into a storage tank;
introducing a carrier gas into the storage tank to mix with the solid
powder to form a gas solid mixture in the storage tank;
conveying the gas solid mixture from the storage tank into a conveying
apparatus via an inlet of the conveying apparatus for adjustment, wherein the
conveying apparatus comprises a conveying pipeline and a supplementary gas
pipeline in fluid communication with the conveying pipeline, and wherein the
conveying pipeline comprises:
an expanding portion defining the inlet;
a shrinking portion defining an outlet; and
an intermediate portion disposed between and in fluid
communication with the expanding portion and the shrinking portion; and
conveying the adjusted gas solid mixture out of the conveying
apparatus via the outlet of the shrinking portion.
17. The conveying method of claim 16, further comprising conveying the
gas solid mixture from the storage tank into a first feeding pipeline prioi to
introduction of the gas solid mixture into the conveying apparatus.
18. The conveying method of claim 17, further comprising conveying the
adjusted gas solid mixture into a gasifier for gasification through a second feecing
pipeline after the adjusted gas solid mixture is conveyed out of the conveying
apparatus.
14
19. The conveying method of claim 16, wherein the step of conveyilng the
gas solid mixture into the conveying apparatus for adjustment further comprises:
separating at least a portion of the gas from the solid powder in the gas
solid mixture in the expandng portion with the introduction of the gas solid mixture
into the conveying apparatus; and
mixing and conveying the gas and the solid powder in the shrinking
portion.
20. The conveying method of claim 19, further comprising introducing a
supplementary gas into the shrinking portion of the conveying pipeline to mix with
and convey the solid powder.
21. The conveying method of claim 16, wherein diameters of the
expanding portion increase along a direction from the inlet to the outlet, and where
diameters of the shrinlung portion decrease along the direction from the inlet to the
, outlet.