U.S. patent application number 16/958454 was filed with the patent office on 2021-05-13 for cryogenic rectification process-based method for producing air product, and air separation system.
This patent application is currently assigned to L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude. The applicant listed for this patent is Alain BRIGLIA, L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude, Fengjie XUE, Bowei ZHAO. Invention is credited to Alain BRIGLIA, Fengjie XUE, Bowei ZHAO.
Application Number | 20210140708 16/958454 |
Document ID | / |
Family ID | 1000005356378 |
Filed Date | 2021-05-13 |
![](/patent/app/20210140708/US20210140708A1-20210513\US20210140708A1-2021051)
United States Patent
Application |
20210140708 |
Kind Code |
A1 |
ZHAO; Bowei ; et
al. |
May 13, 2021 |
CRYOGENIC RECTIFICATION PROCESS-BASED METHOD FOR PRODUCING AIR
PRODUCT, AND AIR SEPARATION SYSTEM
Abstract
The present invention discloses a cryogenic rectification
process-based method for producing an air product, and an air
separation system. By adding an air product outlet line and a
liquid air booster pump to an existing cryogenic rectification
process apparatus, the existing rectification apparatus is used to
prepare oxygen-enriched liquid air by pressurizing, cooling and
liquefying feed air; and moreover, a high-pressure or
ultra-high-pressure air product can be prepared according to
customer requirements by adjusting the ratio of the feed air to the
oxygen-enriched liquid air, and pressurizing the mixture to a
target pressure by the liquid air booster pump before being
vaporized via heat exchange with a gas or liquid product produced
by rectification through a heat exchange apparatus. According to
the present invention, when gas or liquid products of oxygen and
nitrogen are produced by means of rectification, a high-pressure or
ultra-high-pressure air product can be provided according to
customer requirements, and there is no need to provide an
additional air compressor or passively increase the discharge
pressure of the air booster, so that the production costs are
greatly reduced and the energy efficiency level is improved. The
method of the present invention can also improve the stability of
devices, especially when a small amount of
high-pressure/ultra-high-pressure air product needs to be
produced.
Inventors: |
ZHAO; Bowei; (Hangzhou,
CN) ; BRIGLIA; Alain; (Hangzhou, CN) ; XUE;
Fengjie; (Hangzhou, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZHAO; Bowei
BRIGLIA; Alain
XUE; Fengjie
L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des
Procedes Georges Claude |
Hangzhou, Zhejiang
Hangzhou, Zhejiang
Hangzhou, Zhejiang
Paris |
|
CN
CN
CN
FR |
|
|
Assignee: |
L'Air Liquide, Societe Anonyme pour
l'Etude et l'Exploitation des Procedes Georges Claude
Paris
FR
|
Family ID: |
1000005356378 |
Appl. No.: |
16/958454 |
Filed: |
December 28, 2017 |
PCT Filed: |
December 28, 2017 |
PCT NO: |
PCT/CN2017/119240 |
371 Date: |
January 19, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25J 3/04412 20130101;
F25J 2215/40 20130101; F25J 3/0409 20130101; F25J 3/04296 20130101;
F25J 2245/40 20130101; F25J 3/04084 20130101; F25J 2240/10
20130101; F25J 3/04387 20130101 |
International
Class: |
F25J 3/04 20060101
F25J003/04 |
Claims
1-26. (canceled)
27. A cryogenic rectification process-based method for producing an
air product, comprising: a. providing an air separation system for
preparing a nitrogen product and/or an oxygen product, which
comprises: a rectification column, at least one air boost system,
at least one air pre-cooling apparatus, at least one air
purification apparatus and at least one heat exchange apparatus,
wherein the rectification column comprises a first column with a
first pressure, a second column with a second pressure and a main
condensation and evaporation apparatus arranged at the bottom of
the second column; and the air boost system comprises a main air
compressor and at least one air booster; b. after passing feed air
sequentially through the main air compressor for pressurization to
a first pressure range, the air pre-cooling apparatus for
pre-cooling and the air purification apparatus for purification,
splitting off one portion thereof as a first air stream for heat
exchange through the heat exchange apparatus with a gas or liquid
product produced by rectification, and then introducing the first
air stream after cooling down into the first column for
rectification; and the other portion passing through the air
booster for pressurization to a third pressure range before being
split into a second air stream and a third air stream, the second
air stream passing through the heat exchange apparatus for heat
exchange with the gas or liquid product produced by rectification
and being discharged from a middle part of the heat exchange
apparatus into an air expander for depressurization to the first
pressure range before being introduced into the first column for
rectification; and the third air stream passing through the heat
exchange apparatus for heat exchange with the gas or liquid product
produced by rectification, and after cooling down, being
depressurized to the first pressure range for introduction into the
first column or depressurized to a second pressure range for
introduction into the second column; c. providing a liquid nitrogen
line and an oxygen-enriched liquid air line which introduce liquid
nitrogen at the top of the first column and oxygen-enriched liquid
air at the bottom of the first column, respectively, into the
second column as reflux for rectification; and d. providing an air
product outlet line in which at least one liquid air booster pump
is arranged, and discharging the oxygen-enriched liquid air or at
least partially liquefied feed air of the third air stream from the
bottom of the first column through the air product outlet line,
into the liquid air booster pump for pressurization to a target
pressure, and then into the heat exchange apparatus for
vaporization via heat exchange so as to obtain the required air
product.
28. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, wherein the air expander
uses an expander booster for braking, the third air stream is first
pressurized to a fourth pressure range by the expander booster,
then enters the heat exchange apparatus for heat exchange with the
gas or liquid product produced by rectification, and after cooling
down, is depressurized to a first pressure range by a pressure
reducing apparatus and then introduced into the first column.
29. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, wherein the pressure
reducing apparatus is a throttle valve or a liquid expander.
30. The cryogenic rectification process-based method for producing
an air product as claimed in claim 29, wherein the liquid expander
is braked by a generator.
31. The cryogenic rectification process-based method for producing
an air product as claimed in claim 28, wherein a fourth air stream
is further split off from the third air stream that has been
depressurized to the first pressure range, and the fourth air
stream is introduced into the second column after being throttled
and depressurized to the second pressure range by a throttle
valve.
32. The cryogenic rectification process-based method for producing
an air product as claimed in claim 31, wherein a fifth air stream
is further split off from the fourth air stream, the fifth air
stream is connected to the air product outlet line, and the flow
rate and flow velocity of the fifth air stream are controlled via a
first regulating valve.
33. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, wherein the air product
outlet line is further provided with a second regulating valve for
controlling the flow rate and flow velocity of the oxygen-enriched
liquid air.
34. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, wherein the heat exchange
apparatus comprises a low-pressure plate heat exchanger and a
high-pressure plate heat exchanger, or an integral combined heat
exchanger.
35. The cryogenic rectification process-based method for producing
an air product as claimed in claim 34, wherein the heat exchange
apparatus further comprises a subcooler through which the reflux
entering the second column exchanges heat with the gas or liquid
product rectified by the second column.
36. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, further comprising: drawing
a liquid nitrogen fraction from the first column into the second
column as reflux.
37. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, further comprising: drawing
liquid oxygen from the main condensation and evaporation apparatus
through a liquid oxygen booster pump for pressurization to a
required pressure and then into the heat exchange apparatus for
vaporization via heat exchange for preparation of the oxygen
product.
38. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, further comprising: drawing
the liquid nitrogen from the top of the first column directly into
the heat exchange apparatus for vaporization via heat exchange for
preparation of a first nitrogen product; or, drawing the liquid
nitrogen from the top of the first column through a liquid nitrogen
booster pump first for pressurization to a required pressure and
then into the heat exchange apparatus for vaporization via heat
exchange for preparation of a second nitrogen product.
39. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, further comprising: drawing
ultra-low-pressure nitrogen from the top of the second column into
the heat exchange apparatus for reheating to prepare a third
nitrogen product.
40. The cryogenic rectification process-based method for producing
an air product as claimed in claim 27, further comprising: drawing
waste nitrogen from an upper part of the second column into the
heat exchange apparatus for reheating to obtain a waste nitrogen
product.
41. An air separation system for producing an air product based on
a cryogenic rectification process, the air separation system
comprising: a. a rectification column, which comprises: a first
column with a first pressure, a second column with a second
pressure and a main condensation and evaporation apparatus arranged
at the bottom of the second column; and a liquid nitrogen line for
guiding liquid nitrogen from the top of the first column through a
throttle valve into the second column and an oxygen-enriched liquid
air line for guiding oxygen-enriched liquid air from the bottom of
the first column through the throttle valve into the second column
arranged between the first column and the second column; b. at
least one air boost system, at least one air pre-cooling apparatus,
at least one air purification apparatus, at least one heat exchange
apparatus, at least one air expander, at least one liquid oxygen
booster pump, at least one liquid air booster pump and a plurality
of pressure reducing apparatuses, the air boost system comprising a
main air compressor and at least one air booster; c. a first air
inlet line for guiding feed air through the main air compressor,
the air pre-cooling apparatus, the air purification apparatus and
the heat exchange apparatus into the first column; a second air
inlet line for guiding feed air through the main air compressor,
the air pre-cooling apparatus and the air purification apparatus,
out of the heat exchange apparatus and then through the air
expander into the first column; and a third air inlet line further
branching off from the second air inlet line before the second air
inlet line enters the heat exchange apparatus, the third air inlet
line passing through the heat exchange apparatus directly and being
connected to the first column or the second column via the pressure
reducing apparatus; d. a liquid oxygen product outlet line for
discharging liquid oxygen from the main condensation and
evaporation apparatus through the at least one liquid oxygen
booster pump and then through the heat exchange apparatus; and e.
an air product outlet line connected to the bottom of the first
column or the third air inlet line, the air product outlet line
being provided with the at least one liquid air booster pump to
pressurize at least partially liquefied feed air from the third air
inlet line or the oxygen-enriched liquid air discharged from the
bottom of the first column to a target pressure for vaporization
via heat exchange through the heat exchange apparatus so as to
output the required air product.
42. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 41, wherein
the air expander is braked by an expander booster provided, and the
third air inlet line is connected via the expander booster and
subsequently the heat exchange apparatus and the pressure reducing
apparatus to the first column.
43. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 42, further
comprising a fourth air inlet line, which branches off from the
third air inlet line connecting the pressure reducing apparatus to
the first column and is connected to the second column via the
throttle valve.
44. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 43, wherein a
throttle valve or a liquid expander is selected as the pressure
reducing apparatus.
45. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 43, wherein a
fifth air inlet line further branches off from the fourth air inlet
line, the fifth air inlet line being connected to the air product
outlet line for outputting the required air product discharged
through the liquid air booster pump and the heat exchange
apparatus.
46. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 45, wherein
the fifth air inlet line is further provided with a first
regulating valve for controlling the flow rate and flow velocity of
an air stream.
47. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 41, wherein
the air product outlet line is further provided with a second
regulating valve for controlling the flow rate and flow velocity of
the oxygen-enriched liquid air.
48. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 41, further
comprising: a first nitrogen product outlet line for vaporizing the
liquid nitrogen from the top of the first column via heat exchange
through the heat exchange apparatus for preparation of a first
nitrogen product; or, at least one liquid nitrogen booster pump,
and a second nitrogen product outlet line passing the liquid
nitrogen drawn from the top of the first column through the at
least one liquid nitrogen booster pump first for pressurization to
a required pressure and then into the heat exchange apparatus for
vaporization via heat exchange for preparation of a second nitrogen
product; or, a third nitrogen product outlet line discharging
nitrogen from the top of the second column through the heat
exchange apparatus.
49. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 41, wherein a
liquid nitrogen fraction line for guiding a liquid nitrogen
fraction from the first column through the throttle valve into the
second column is further arranged between the first column and the
second column.
50. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 49, further
comprising a waste nitrogen line for discharging waste nitrogen
from the second column through the heat exchange apparatus.
51. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 41, wherein
the heat exchange apparatus comprises a high-pressure plate heat
exchanger and a low-pressure plate heat exchanger, or an integral
combined heat exchanger.
52. The air separation system for producing an air product based on
a cryogenic rectification process as claimed in claim 51, wherein
the heat exchange apparatus further comprises a subcooler for the
reflux entering the second column to exchange heat with the gas or
liquid product rectified by the second column.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a .sctn. 371 of International PCT
Application PCT/CN2017/119240, filed Dec. 28, 2017, which is herein
incorporated by reference in its entirety.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention belongs to the field of air separation
and relates to an air separation process, in particular to a
cryogenic rectification process-based method for producing an air
product, and an air separation system.
BACKGROUND OF THE INVENTION
[0003] Cryogenic rectification is essentially a technology for gas
liquefaction, in which mechanical methods, such as throttling
expansion or adiabatic expansion, are usually used to compress and
cool gases, and then rectify the gases by taking advantage of the
difference in boiling points of different gases to separate the
different gases. Specifically, air is taken as a feedstock and
liquefied after being subject to compression, purification and heat
exchange, and nitrogen and oxygen are obtained after separation
through rectification by taking advantage of different boiling
points of liquid oxygen and liquid nitrogen.
[0004] Using cryogenic rectification to separate air into nitrogen
and oxygen products is a common and sophisticated technology. At
least two air separation columns (a medium-pressure column and a
low-pressure column) operating at different pressures communicate
with each other in a heat exchange manner through a main
condenser/evaporator. Pressurized, purified and cooled feed air is
fed into the medium-pressure column and/or the low-pressure column,
and gaseous and/or liquid nitrogen and oxygen products are obtained
through rectification. All or part of the nitrogen and oxygen
exchange heat with the feed air in a main heat exchanger to obtain
gaseous nitrogen and oxygen products at a normal atmospheric
temperature. The design of the air separation system and process is
generally based on customer requirements on the state, pressure and
output scale of the nitrogen and oxygen products. To produce an
oxygen and/or nitrogen product with a high pressure, e.g., greater
than 40 bara, there may be two modes to choose from, i.e., an
external pressurization mode in which gaseous oxygen or nitrogen
that has been reheated to the normal atmospheric temperature
through the main heat exchanger is passed through a corresponding
booster for pressurization, or an internal pressurization mode in
which liquid oxygen or liquid nitrogen at a low temperature is
boosted to a required pressure using a pump before being reheated
by the main heat exchanger.
[0005] In coal chemical projects, the internal compression process
is widely used in modern air separation. To produce a
medium-pressure or high-pressure air product, an air booster is
usually provided, through which the required medium-pressure or
high-pressure air product can be produced. However, to produce an
air product with a pressure higher than a discharge pressure of the
air booster itself, it is no longer viable to rely solely on this
air booster, and it is usually necessary to provide an additional
high-pressure/ultra-high-pressure compressor or passively increase
the discharge pressure of the air booster. However, all these
methods will compromise the overall energy consumption level of the
air separation device.
SUMMARY OF THE INVENTION
[0006] The purpose of certain embodiments of the present invention
is to avoid being forced to set up an additional air compressor or
passively increasing the discharge pressure of the air booster. By
utilizing an existing cryogenic rectification process apparatus,
pressurized and at least partially liquefied feed air and/or
oxygen-enriched liquid air is passed through a liquid air booster
pump for pressurization to a required high pressure or ultra-high
pressure, and then a high-pressure or ultra-high-pressure air
product is discharged along an air product outlet line after
vaporization via heat exchange through a heat exchange apparatus.
The present invention can not only improve the energy efficiency,
but also reduce the costs and improve the stability of the device.
The air product can be air, air mixed with oxygen-enriched liquid
air, or oxygen-enriched liquid air.
[0007] In order to achieve the above object, the present invention
provides a cryogenic rectification process-based method for
producing an air product, comprising:
[0008] (a) providing an air separation system for preparing a
nitrogen product and/or an oxygen product, which comprises: a
rectification column, at least one air boost system, at least one
air pre-cooling apparatus, at least one air purification apparatus
and at least one heat exchange apparatus, wherein the rectification
column comprises a first column with a first pressure, a second
column with a second pressure and a main condensation and
evaporation apparatus arranged at the bottom of the second column;
and the air boost system comprises a main air compressor and at
least one air booster;
[0009] (b) after passing feed air sequentially through the main air
compressor for pressurization to a first pressure range, the air
pre-cooling apparatus for pre-cooling and the air purification
apparatus for purification, splitting off one portion thereof as a
first air stream for heat exchange through the heat exchange
apparatus with a gas or liquid product produced by rectification,
and then introducing the first air stream after cooling down into
the first column for rectification; and the other portion passing
through the air booster for pressurization to a third pressure
range before being split into a second air stream and a third air
stream, the second air stream passing through the heat exchange
apparatus for heat exchange with the gas or liquid product produced
by rectification and being discharged from a middle part of the
heat exchange apparatus into an air expander for depressurization
to the first pressure range before being introduced into the first
column for rectification; and the third air stream passing through
the heat exchange apparatus for heat exchange with the gas or
liquid product produced by rectification, and after cooling down,
being depressurized to the first pressure range for introduction
into the first column or depressurized to a second pressure range
for introduction into the second column; and
[0010] (c) providing a liquid nitrogen line and an oxygen-enriched
liquid air line which introduce liquid nitrogen at the top of the
first column and oxygen-enriched liquid air at the bottom of the
first column, respectively, into the second column as reflux for
rectification;
[0011] the method further comprising: providing an air product
outlet line in which at least one liquid air booster pump is
arranged, and discharging the oxygen-enriched liquid air or at
least partially liquefied feed air of the third air stream from the
bottom of the first column through the air product outlet line,
into the liquid air booster pump for pressurization to a target
pressure, and then into the heat exchange apparatus for
vaporization via heat exchange so as to obtain the required air
product.
[0012] Preferably, the air expander uses an expander booster for
braking, the third air stream is first pressurized to a fourth
pressure range by the expander booster, then enters the heat
exchange apparatus for heat exchange with the gas or liquid product
produced by rectification, and after cooling down, is depressurized
to a first pressure range by a pressure reducing apparatus and then
introduced into the first column.
[0013] Preferably, the pressure reducing apparatus is a throttle
valve or a liquid expander.
[0014] Preferably, the liquid expander is braked by a
generator.
[0015] Preferably, a fourth air stream is further split off from
the third air stream that has been depressurized to the first
pressure range, and the fourth air stream is introduced into the
second column after being throttled and depressurized to the second
pressure range by a throttle valve.
[0016] Preferably, a fifth air stream is further split off from the
fourth air stream, the fifth air stream is connected to the air
product outlet line, and the flow rate and flow velocity of the
fifth air stream are controlled via a first regulating valve.
[0017] Preferably, the air product outlet line is further provided
with a second regulating valve for controlling the flow rate and
flow velocity of the oxygen-enriched liquid air.
[0018] Preferably, the heat exchange apparatus comprises a
low-pressure plate heat exchanger and a high-pressure plate heat
exchanger, or an integral combined heat exchanger.
[0019] Preferably, the heat exchange apparatus further comprises a
subcooler through which the reflux entering the second column
exchanges heat with the gas or liquid product rectified by the
second column.
[0020] Preferably, the method further comprises: drawing a liquid
nitrogen fraction from the first column into the second column as
reflux.
[0021] Preferably, the method further comprises: drawing liquid
oxygen from the main condensation and evaporation apparatus through
a liquid oxygen booster pump for pressurization to a required
pressure and then into the heat exchange apparatus for heat
exchange and vaporization for preparation of the oxygen
product.
[0022] Preferably, the method further comprises: drawing the liquid
nitrogen from the top of the first column directly into the heat
exchange apparatus for vaporization via heat exchange for
preparation of a first nitrogen product; or, drawing the liquid
nitrogen from the top of the first column through a liquid nitrogen
booster pump first for pressurization to a required pressure and
then into the heat exchange apparatus for vaporization via heat
exchange for preparation of a second nitrogen product.
[0023] Preferably, the method further comprises: drawing
ultra-low-pressure nitrogen from the top of the second column into
the heat exchange apparatus for reheating to prepare a third
nitrogen product.
[0024] Preferably, the method further comprises: drawing waste
nitrogen from an upper part of the second column into the heat
exchange apparatus for reheating to obtain a waste nitrogen
product.
[0025] The present invention also provides an air separation system
for producing an air product based on a cryogenic rectification
process, the air separation system comprising:
[0026] (a) a rectification column, which comprises: a first column
with a first pressure, a second column with a second pressure and a
main condensation and evaporation apparatus arranged at the bottom
of the second column; and a liquid nitrogen line for guiding liquid
nitrogen from the top of the first column through a throttle valve
into the second column and an oxygen-enriched liquid air line for
guiding oxygen-enriched liquid air from the bottom of the first
column through the throttle valve into the second column arranged
between the first column and the second column;
[0027] (b) at least one air boost system, at least one air
pre-cooling apparatus, at least one air purification apparatus, at
least one heat exchange apparatus, at least one air expander, at
least one liquid oxygen booster pump, at least one liquid air
booster pump and a plurality of pressure reducing apparatuses, the
air boost system comprising a main air compressor and at least one
air booster;
[0028] (c) a first air inlet line for guiding feed air through the
main air compressor, the air pre-cooling apparatus, the air
purification apparatus and the heat exchange apparatus into the
first column; a second air inlet line for guiding feed air through
the main air compressor, the air pre-cooling apparatus and the air
purification apparatus, out of the heat exchange apparatus and then
through the air expander into the first column; and a third air
inlet line further branching off from the second air inlet line
before the second air inlet line enters the heat exchange
apparatus, the third air inlet line passing through the heat
exchange apparatus directly and being connected to the first column
or the second column via the pressure reducing apparatus; and
[0029] (d) a liquid oxygen product outlet line for discharging
liquid oxygen from the main condensation and evaporation apparatus
through the at least one liquid oxygen booster pump and then
through the heat exchange apparatus;
[0030] and further comprising: an air product outlet line connected
to the bottom of the first column or the third air inlet line, the
air product outlet line being provided with the at least one liquid
air booster pump to pressurize at least partially liquefied feed
air from the third air inlet line or the oxygen-enriched liquid air
discharged from the bottom of the first column to a target pressure
for vaporization via heat exchange through the heat exchange
apparatus so as to output the required air product.
[0031] Preferably, the air expander is braked by an expander
booster provided, and the third air inlet line is connected via the
expander booster and subsequently the heat exchange apparatus and
the pressure reducing apparatus to the first column.
[0032] Preferably, the system further comprises a fourth air inlet
line, which branches off from the third air inlet line connecting
the pressure reducing apparatus to the first column and is
connected to the second column via the throttle valve.
[0033] Preferably, a fifth air inlet line further branches off from
the fourth air inlet line, the fifth air inlet line being connected
to the air product outlet line for outputting a high-pressure or
ultra-high-pressure air product discharged through the liquid air
booster pump and the heat exchange apparatus.
[0034] Preferably, the fifth air inlet line is further provided
with a first regulating valve for controlling the flow rate and
flow velocity of an air stream; and the air product outlet line is
further provided with a second regulating valve for controlling the
flow rate and flow velocity of the oxygen-enriched liquid air.
[0035] Preferably, the system further comprises: a first nitrogen
product outlet line for vaporizing the liquid nitrogen from the top
of the first column via heat exchange through the heat exchange
apparatus for preparation of a first nitrogen product; or, at least
one liquid nitrogen booster pump, and a second nitrogen product
outlet line passing the liquid nitrogen drawn from the top of the
first column through the at least one liquid nitrogen booster pump
first for pressurization to a required pressure and then into the
heat exchange apparatus for vaporization via heat exchange for
preparation of a second nitrogen product; or, a third nitrogen
product outlet line discharging nitrogen from the top of the second
column through the heat exchange apparatus.
[0036] Preferably, a liquid nitrogen fraction line for guiding a
liquid nitrogen fraction from the first column through the throttle
valve into the second column is further arranged between the first
column and the second column.
[0037] Preferably, the system further comprises a waste nitrogen
line for discharging waste nitrogen from the second column through
the heat exchange apparatus.
[0038] The method provided by the present invention for producing a
high-pressure or ultra-high-pressure air product uses the existing
cryogenic rectification process apparatus. According to customer
requirements, the oxygen-enriched liquid air produced by
rectification from the rectification column, or the feed air that
is pressurized and cooled so as to be at least partially liquefied,
or the oxygen-enriched liquid air mixed with the at least partially
liquefied feed air at an required ratio is passed through a liquid
air booster pump for pressurization to a required high pressure or
ultra-high pressure, and then a high-pressure or
ultra-high-pressure air product is discharged along an air product
outlet line after vaporization via heat exchange through a heat
exchange apparatus. According to the present invention, there is no
need to provide an additional air compressor or passively increase
the discharge pressure of the air booster, so that the production
costs are greatly reduced and the energy efficiency level is
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Further features, advantages and possible applications of
the invention are apparent from the following description of
working and numerical examples and from the drawings. All described
and/or depicted features on their own or in any desired combination
form the subject matter of the invention, irrespective of the way
in which they are combined in the claims or the way in which said
claims refer back to one another.
[0040] FIG. 1 is a schematic structural diagram of an air
separation system for producing an air product based on a cryogenic
rectification process of the present invention, with an air product
outlet line 113 connected to both a fifth air inlet line 105 and an
oxygen-enriched liquid air bottom.
[0041] FIG. 2 is a schematic structural diagram of another air
separation system for producing an air product based on a cryogenic
rectification process of the present invention, with the air
product outlet line 113 connected to the fifth air inlet line 105
only.
DETAILED DESCRIPTION OF THE INVENTION
[0042] The technical solution of the present invention is explained
further below in conjunction with the accompanying drawings and
embodiments.
[0043] In the present invention, the term "feed air" refers to a
mixture mainly containing oxygen and nitrogen.
[0044] The term "waste nitrogen" refers to a gaseous fluid with a
nitrogen purity generally no less than 95%; and the term "liquid
nitrogen fraction" refers to a liquid fluid with a nitrogen purity
generally greater than 95%, all of which are expressed in mole
percent.
[0045] The term "oxygen-enriched liquid air" refers to a liquid
fluid with an oxygen purity greater than 30%; the term "liquid air"
refers to a liquid fluid with an oxygen purity no greater than 30%;
and the term "liquid oxygen" refers to a liquid fluid with an
oxygen purity greater than 99%, the oxygen purity of the "liquid
oxygen" being higher than that of the "oxygen-enriched liquid air",
all of which are expressed in mole percent.
[0046] The pressure range indicated by the term "medium pressure"
is 5-30 bara, the pressure range indicated by the term "high
pressure" is 30-80 bara, and the pressure range indicated by the
term "ultra-high pressure" is over 80 bara.
[0047] In the present invention, the "first pressure range" is
consistent with the working pressure range of the first column
(medium-pressure column), which is generally 5-6.5 bara, and the
feed air at a normal atmospheric pressure can be compressed by the
main air compressor to reach this pressure range. The "second
pressure range" is consistent with the working pressure range of
the second column (low-pressure column), which is generally 1.1-1.5
bara. The "third pressure range" is a pressure range that the feed
air in the first pressure range reaches after being pressurized by
an air booster, which is generally 40-60 bara. The "fourth pressure
range" is a pressure range the feed air in the third pressure range
reaches after being further pressurized by an expander booster,
which is generally 60-75 bara. The feed air in the third and fourth
pressure ranges needs to be able to exchange heat with and thus
vaporize the pressurized liquid oxygen in the heat exchange
apparatus, so its specific pressure is determined by the pressure
of the liquid oxygen to be vaporized.
[0048] The cryogenic rectification of the present invention is a
rectification method at least partially carried out at a
temperature of 150 K or lower than 150 K. As used herein, the term
"column" means a distillation or fractionating column or zone in
which liquid and gas phases are in countercurrent contact to
effectively separate the fluid mixture. In the present invention,
the operating pressure of the "first column" is generally 5-6.5
bara, which is higher than the general operating pressure of the
"second column" of 1.1-1.5 bara. The second column can be installed
vertically on top of the first column or the two columns can be
installed side by side. The "first column" is also commonly
referred to as a medium-pressure column or a lower column, and the
"second column" is also commonly referred to as a low-pressure
column or an upper column. The main condensation and evaporation
apparatus is generally located at the bottom of the "second
column", which can produce pure liquid nitrogen at the top of the
first column after condensing the pure nitrogen gas produced at the
top of the first column via heat exchange with the pure liquid
oxygen produced at the bottom of the second column, and evaporate
the pure liquid oxygen partially at the same time. The types of
main condensation and evaporation apparatus include a
shell-and-tube type, a falling film type, an immersion type, etc.
In the present invention, an immersion type condenser/evaporator
can be used.
[0049] An air pre-cooling apparatus in the present invention is
used to pre-cool high temperature air (70-120.degree. C.)
discharged from the main air compressor to a temperature suitable
for entering an air purification apparatus (generally at
10-25.degree. C.). High-temperature air generally exchanges heat by
contact with common circulating cooling water and low-temperature
water (generally at 5-20.degree. C.) in an air cooling column to
achieve the purpose of cooling. The low-temperature water can be
obtained with the ordinary circulating cooling water via heat
exchange by contact with a gas product or by-product, such as the
waste nitrogen, produced by the air separation apparatus, or by
means of a refrigerator.
[0050] The air purification apparatus refers to a purification
device that removes dust, water vapor, CO.sub.2, hydrocarbons, etc.
from the air. In the present invention, a pressure swing adsorption
method is generally used, in which an adsorbent involved may
optionally be a molecular sieve plus alumina, or a molecular sieve
only.
[0051] In the main heat exchanger, the compressed, pre-cooled and
purified feed air is subject to non-contact heat exchange with the
gas and/or liquid product produced by rectification and is cooled
to a temperature close to or equal to the rectification temperature
of the first column, generally lower than 150 K. Common main heat
exchangers include split or integrated types, etc. The main heat
exchangers are divided into high-pressure (>20 bara pressure)
and low-pressure (<20 bara pressure) heat exchangers according
to proper pressure ranges. The present invention can use both a
high-pressure plate heat exchanger and a low-pressure plate heat
exchanger, or an integral combined heat exchanger.
[0052] The present invention provides an air separation system for
producing an air product based on a cryogenic rectification
process, which is an air separation system for producing a
high-pressure or ultra-high-pressure air product by adding an air
product outlet line and at least one liquid air booster pump to an
existing cryogenic rectification process device.
[0053] As shown in FIG. 1, an air separation system for producing
an air product based on a cryogenic rectification process of the
present invention comprises:
[0054] (a) a rectification column, which comprises: a first column
11 (a medium-pressure column) with a first pressure, a second
column 12 (a low-pressure column) with a second pressure and a main
condensation and evaporation apparatus 13 arranged at the bottom of
the second column 12; and a liquid nitrogen line 111 for guiding
liquid nitrogen from the top of the first column 11 through a
throttle valve 14 into the second column 12 and an oxygen-enriched
liquid air line 112 for guiding oxygen-enriched liquid air from the
bottom of the first column 11 through the throttle valve 14 into
the second column 12 arranged between the first column 11 and the
second column 12;
[0055] (b) at least one air boost system, at least one air
pre-cooling apparatus 40, at least one air purification apparatus
50, at least one heat exchange apparatus, at least one air expander
1021, at least one liquid oxygen booster pump 1311, at least one
liquid air booster pump 1131 and a plurality of pressure reducing
apparatuses, the air boost system comprising a main air compressor
21 and at least one air booster 22;
[0056] (c) a first air inlet line 101 for guiding feed air through
the main air compressor 21, the air pre-cooling apparatus 40, the
air purification apparatus 50 and the heat exchange apparatus into
the first column 11; a second air inlet line 102 for guiding feed
air through the main air compressor 21, the air pre-cooling
apparatus 40, the air purification apparatus 50 and the heat
exchange apparatus, and discharging same from a middle part of the
heat exchange apparatus (the middle part is not limited to the very
center of the heat exchange apparatus, and instead refers to the
incompletely liquefied air being discharged before completely
passing through the heat exchange apparatus) and then through the
air expander 1021 (which is braked by an expander booster 1031
provided) into the first column 11; and a third air inlet line 103
further branching off from the second air inlet line 102 before the
second air inlet line enters the heat exchange apparatus, the third
air inlet line 103 being connected to the first column 11 via the
expander booster 1031 and then via the heat exchange apparatus and
the pressure reducing apparatus;
[0057] (d) a liquid oxygen product outlet line 131 for discharging
liquid oxygen from the main condensation and evaporation apparatus
13 through the at least one liquid oxygen booster pump 1311 and
then through the heat exchange apparatus; and
[0058] (e) an air product outlet line 113 connected to the bottom
of the first column 11 or the third air inlet line 103, wherein the
air product outlet line 113 is provided with the at least one
liquid air booster pump 1131, and oxygen-enriched liquid air
discharged from the bottom of the first column 11 and/or at least
partially liquefied feed air discharged from the third air inlet
line 103 is pressurized to a target pressure via the at least one
liquid air booster pump 1131 for vaporization via heat exchange
through the heat exchange apparatus so as to output the required
high-pressure or ultra-high-pressure air product, which can be the
oxygen-enriched liquid air, the feed air, or a mixture of the
oxygen-enriched liquid air and the feed air.
[0059] In some embodiments, a fourth air inlet line 104 further
branches off from the third air inlet line 103 between the pressure
reducing apparatus and the first column 11 and is connected to the
second column 12 via the throttle valve 14 for directly feeding the
liquefied feed air into the second column 12.
[0060] In some embodiments, a fifth air inlet line 105 further
branches off from the fourth air inlet line 104 and is connected to
the air product outlet line 113 for guiding the at least partially
liquefied feed air discharged from the third air inlet line 103
into the air product outlet line 113 to be mixed with
oxygen-enriched liquid air, and the mixture is pressurized to a
target pressure via the at least one liquid air booster pump 1131
for vaporization via heat exchange through the heat exchange
apparatus so as to output the required high-pressure or
ultra-high-pressure air product, which is a mixture of the
oxygen-enriched liquid air and the feed air.
[0061] In some embodiments, the fifth air inlet line 105 is further
provided with a first regulating valve 1051, which is used to
control the flow rate and flow velocity of the air stream and can
control the mixing ratio of the feed air to the oxygen-enriched
liquid air so as to obtain the air product with the required oxygen
ratio. The first regulating valve 1051 can also be closed on demand
in order that the air product outlet line 113 only outputs
oxygen-enriched liquid air.
[0062] In some embodiments, the air product outlet line 113 is
further provided with a second regulating valve 1132, which is used
to control the flow rate and flow velocity of the oxygen-enriched
liquid air and can control the mixing ratio of the feed air to the
oxygen-enriched liquid air so as to obtain the air product with the
required oxygen ratio. The second regulating valve 1132 can also be
closed on demand in order that the air product outlet line 113 only
outputs high-pressure or ultra-high-pressure feed air.
[0063] In some embodiments, the fifth air inlet line 105 is
provided with the first regulating valve 1051, and the air product
outlet line 113 is further provided with the second regulating
valve 1132, so as to accurately adjust the oxygen ratio in the air
product to meet different requirements of customers.
[0064] In some embodiments, the air separation system further
comprises: a first nitrogen product outlet line 115 for vaporizing
the liquid nitrogen from the top of the first column 11 via heat
exchange through the heat exchange apparatus for preparation of a
first nitrogen product.
[0065] In some embodiments, the air separation system further
comprises: at least one liquid nitrogen booster pump 1161, and a
second nitrogen product outlet line 116 passing the liquid nitrogen
drawn from the top of the first column 11 through the at least one
liquid nitrogen booster pump 1161 first for pressurization to a
required pressure and then into the heat exchange apparatus for
vaporization via heat exchange for preparation of a second nitrogen
product.
[0066] In some embodiments, the air separation system further
comprises a third nitrogen product outlet line 121 discharging
nitrogen from the top of the second column 12 through the heat
exchange apparatus.
[0067] In some embodiments, the air separation system further
comprises: a waste nitrogen line 122 for discharging waste nitrogen
from the second column 12 through the heat exchange apparatus.
[0068] In some embodiments, a liquid nitrogen fraction line 114 for
guiding a liquid nitrogen fraction from the first column 11 through
the throttle valve 14 into the second column 12 is further provided
between the first column 11 and the second column 12.
[0069] In some embodiments, the heat exchange apparatus comprises a
low-pressure plate heat exchanger 31 and a high-pressure plate heat
exchanger 32 as the main heat exchanger.
[0070] In some embodiments, the heat exchange apparatus uses an
integral combined heat exchanger as the main heat exchanger.
[0071] In some embodiments, the heat exchange apparatus further
comprises a subcooler 33 for the reflux entering the second column
12 to exchange heat with the gas or liquid product rectified by the
second column 12.
[0072] In some embodiments, a throttle valve or a liquid expander
1032 is selected as the pressure reducing apparatus.
[0073] In some embodiments, the air expander 1021 in the second air
inlet line 102 is braked by a generator. A third air inlet line 103
further branches off from the second air inlet line 102 before the
second air inlet line enters the heat exchange apparatus, the third
air inlet line 103 passing through the heat exchange apparatus
directly and completely and being connected to the first column 11
or the second column 12 via the pressure reducing apparatus.
[0074] In some embodiments, the air product outlet line 113 is only
connected to the third air inlet line 103 (not connected to the
bottom of the first column 11), the air product outlet line 113 is
provided with the at least one liquid air booster pump 1131, and at
least partially liquefied feed air discharged from the third air
inlet line 103 is pressurized to a target pressure via the at least
one liquid air booster pump 1131 for vaporization via heat exchange
through the heat exchange apparatus so as to output the required
high-pressure or ultra-high-pressure air product, which is
high-pressure or ultra-high-pressure feed air.
[0075] In some embodiments, as shown in FIG. 2, the air product
outlet line 113 is only connected to the fifth air inlet line 105,
and is not connected to the bottom of the first column 11, i.e.,
does not discharge the oxygen-enriched liquid air. The air product
outlet line 113 is provided with the at least one liquid air
booster pump 1131, and at least partially liquefied feed air
discharged from the fifth air inlet line 105 is pressurized to a
target pressure via the at least one liquid air booster pump 1131
for vaporization via heat exchange through the heat exchange
apparatus so as to output the required high-pressure or
ultra-high-pressure air product, which is high-pressure or
ultra-high-pressure feed air.
[0076] In some embodiments, the fifth air inlet line 105 is further
provided with the first regulating valve 1051 to control the flow
rate and flow velocity of the feed air.
[0077] The method for producing a high-pressure or
ultra-high-pressure air product by using the air separation system
of the present invention will be described in detail below with
reference to embodiments.
Embodiment 1
[0078] After feed air (1 bara) sequentially passes through the main
air compressor 21 for pressurization to 6 bara (the first pressure
range), the air pre-cooling apparatus 40 for pre-cooling and the
air purification apparatus 50 for purification, one portion thereof
is split off as a first air stream guided along the first air inlet
line 101, through the heat exchange apparatus (the low-pressure
plate heat exchanger 31) for heat exchange with a gas or liquid
product produced by rectification (e.g., liquid nitrogen discharged
from the top of the first column, and/or liquid nitrogen discharged
from the top of the second column, and/or a liquid nitrogen
fraction discharged from an upper part of the second column), and
after cooling down (6 bara), into the first column 11 for
rectification; and the other portion passes through the air booster
22 for pressurization to 50 bara (the third pressure range) before
being split into a second air stream and a third air stream: the
second air stream is guided along the second air inlet line 102
through the heat exchange apparatus (the high-pressure plate heat
exchanger 32) for heat exchange with the gas or liquid product
produced by rectification (e.g., liquid oxygen from the main
condensation and evaporation apparatus, and/or liquid nitrogen from
the top of the first column, and/or the high-pressure or
ultra-high-pressure air product from the air product outlet line)
and is discharged from a middle part of the heat exchange apparatus
(the high-pressure plate heat exchanger 32) into the air expander
1021 for depressurization to 6 bara (the first pressure range)
before being introduced into the first column 11 for rectification;
and the third air stream is guided along the third air inlet line
103, first pressurized to 70 bara (the fourth pressure range) by
the expander booster 1031, then enters the heat exchange apparatus
(the high-pressure plate heat exchanger 32) for heat exchange with
the gas or liquid product produced by rectification, and after
cooling down, is depressurized to 6 bara (the first pressure range)
by the pressure reducing apparatus (the liquid expander 1032) and
then introduced into the first column 11.
[0079] A fourth air stream is further split off from the third air
stream that has been depressurized to the first pressure range, and
the fourth air stream is guided along the fourth air inlet line
104, and introduced into the second column 12 as reflux after being
first cooled to subcooled liquid air by the subcooler 33 and then
throttled and depressurized to 1.2 bara (the second pressure range)
by the throttle valve 14.
[0080] A fifth air stream is further split off from the fourth air
stream, the fifth air stream is connected to the air product outlet
line 113, and the flow rate and flow velocity of the fifth air
stream are controlled via a first regulating valve 1132.
[0081] The oxygen-enriched liquid air discharged from the bottom of
the first column and the fifth air stream are mixed in the air
product outlet line 113. The ratio of the oxygen-enriched liquid
air to the feed air is adjusted by the first regulating valve 1051
and the second regulating valve 1132 so as to accurately adjust the
oxygen ratio in the air product. The mixture is further pressurized
to 80 bara via the liquid air booster pump 1131 for subsequent
vaporization via heat exchange through the heat exchange apparatus
(the high-pressure plate heat exchanger 32) so as to obtain the
required high-pressure or ultra-high-pressure air product (80-bara
air product), to meet different customer requirements.
[0082] In some embodiments, in the rectification column, the liquid
nitrogen (5.5 bara LIN) at the top of the first column 11 is
discharged through the liquid nitrogen line 111, cooled by the
subcooler 33, and depressurized to 1.1 bara via the throttle valve
14 and then introduced into the second column 12 as reflux for
rectification.
[0083] In some embodiments, in the rectification column, the
oxygen-enriched liquid air (6 bara) at the bottom of the first
column 11 is discharged through the oxygen-enriched liquid air line
112, cooled by the subcooler 33, and depressurized to 1.3 bara via
the throttle valve 14 and then introduced into the second column 12
as reflux for rectification.
[0084] In some embodiments, in the rectification column, the liquid
nitrogen fraction (5.8 bara) is drawn from the first column 11
through the liquid nitrogen fraction line 114, depressurized to 1.1
bara via the throttle valve 14, and then introduced into the second
column 12 as reflux for rectification.
[0085] In some embodiments, liquid oxygen (2 bara) is drawn from
the main condensation and evaporation apparatus 13, along the
liquid oxygen product outlet line 131, pressurized to a required
pressure (e.g., 80 bara) through the liquid oxygen booster pump
1311, and then vaporized via heat exchange through the heat
exchange apparatus (the high-pressure plate heat exchanger 32) for
preparation of a high-pressure oxygen product of 80 bara.
[0086] In some embodiments, liquid nitrogen (5.5 bara) is drawn
from the top of the first column 11, along the first nitrogen
product outlet line 115, directly vaporized via heat exchange
through the heat exchange apparatus (the low-pressure plate heat
exchanger 31) for preparation of a low-pressure and high-purity
nitrogen of 5 bara (the first nitrogen product).
[0087] In some embodiments, liquid nitrogen (5.5 bara) is drawn
from the top of the first column 11, along the second liquid
nitrogen product outlet line 116, first pressurized to a required
pressure (e.g., 50 bara) through the liquid nitrogen booster pump
1161, and then vaporized via heat exchange through the heat
exchange apparatus (the high-pressure plate heat exchanger 32) for
preparation of a second nitrogen product of 50 bara.
[0088] In some embodiments, ultra-low-pressure nitrogen (1.1 bara)
is drawn from the top of the second column 12 and reheated by the
heat exchange apparatus (the subcooler 33 and the low-pressure
plate heat exchanger 31) for preparation of ultra-low-pressure
nitrogen of 1.05 bara (a third nitrogen product).
[0089] In some embodiments, waste nitrogen (1.1 bara) is drawn from
an upper part of the second column 12 and reheated by the heat
exchange apparatus (the subcooler 33 and the low-pressure plate
heat exchanger 31) to obtain ultra-low-pressure waste nitrogen of
1.05 bara (a waste nitrogen product).
Embodiment 2
[0090] The cryogenic rectification process system is used to
prepare high-pressure or ultra-high-pressure air: as shown in FIG.
2, the fifth air stream is guided along the fifth air inlet line
105 with its flow velocity and flow rate controlled by the first
regulating valve 1051, and in the air product outlet line 113, is
pressurized to a high pressure or ultra-high pressure by the liquid
air booster pump 1131, and vaporized via heat exchange through the
heat exchange apparatus (the high-pressure plate heat exchanger 32)
to obtain the required high-pressure or ultra-high-pressure air
product, which is pressurized feed air.
[0091] In some embodiments, the flow velocity and flow rate of the
third air stream depressurized to the first pressure range are
optionally controlled by the first regulating valve 1051, and in
the air product outlet line 113, said air stream is pressurized to
a high pressure or ultra-high pressure by the liquid air booster
pump 1131, and vaporized via heat exchange through the heat
exchange apparatus (the high-pressure plate heat exchanger 32) to
obtain the required high-pressure or ultra-high-pressure air
product, which is pressurized feed air.
[0092] In summary, according to the present invention, by adding an
air product outlet line and at least one liquid air booster pump to
an existing cryogenic rectification process apparatus, the existing
rectification apparatus is used to prepare oxygen-enriched liquid
air by rectification, and the gas or liquid product produced by
rectification can also be used to pressurize and cool the feed air
to at least partially liquefy the feed air. Moreover, according to
customer requirements, a high-pressure or ultra-high-pressure air
product can be discharged by adjusting the ratio of the feed air to
the oxygen-enriched liquid air, pressurizing the mixture to a
required high pressure or ultra-high pressure by the liquid air
booster pump, and then guiding the mixture along the air product
outlet line through the heat exchange apparatus for vaporization
via heat exchange with the gas or liquid product produced by
rectification. According to the present invention, there is no need
to provide an additional air compressor or passively increase the
discharge pressure of the air booster, so that the production costs
are greatly reduced and the energy efficiency level is improved.
The method of the present invention can also improve the stability
of devices, especially when a small amount of
high-pressure/ultra-high-pressure air product needs to be produced.
Due to a low flow rate, a piston compressor is required in the
traditional method, while the low-temperature liquid air pump used
in the present invention is more reliable than the piston
compressor.
[0093] Although the content of the present invention has been
presented in detail by means of the preferred embodiments above, it
should be recognized that the description above should not be
considered as a limitation to the present invention. Various
amendments and substitutions to the present invention will be
apparent after perusal of the content above by those skilled in the
art. Thus, the scope of protection of the present invention should
be defined by the attached claims.
[0094] While the invention has been described in conjunction with
specific embodiments thereof, it is evident that many alternatives,
modifications, and variations will be apparent to those skilled in
the art in light of the foregoing description. Accordingly, it is
intended to embrace all such alternatives, modifications, and
variations as fall within the spirit and broad scope of the
appended claims. The present invention may suitably comprise,
consist or consist essentially of the elements disclosed and may be
practiced in the absence of an element not disclosed. Furthermore,
if there is language referring to order, such as first and second,
it should be understood in an exemplary sense and not in a limiting
sense. For example, it can be recognized by those skilled in the
art that certain steps can be combined into a single step.
[0095] The singular forms "a", "an" and "the" include plural
referents, unless the context clearly dictates otherwise.
[0096] "Comprising" in a claim is an open transitional term which
means the subsequently identified claim elements are a nonexclusive
listing (i.e., anything else may be additionally included and
remain within the scope of "comprising"). "Comprising" as used
herein may be replaced by the more limited transitional terms
"consisting essentially of" and "consisting of" unless otherwise
indicated herein.
[0097] "Providing" in a claim is defined to mean furnishing,
supplying, making available, or preparing something. The step may
be performed by any actor in the absence of express language in the
claim to the contrary.
[0098] Optional or optionally means that the subsequently described
event or circumstances may or may not occur. The description
includes instances where the event or circumstance occurs and
instances where it does not occur.
[0099] Ranges may be expressed herein as from about one particular
value, and/or to about another particular value. When such a range
is expressed, it is to be understood that another embodiment is
from the one particular value and/or to the other particular value,
along with all combinations within said range.
[0100] All references identified herein are each hereby
incorporated by reference into this application in their
entireties, as well as for the specific information for which each
is cited.
* * * * *