U.S. patent application number 17/129488 was filed with the patent office on 2021-06-24 for resaturation of gas into a liquid feedstream.
This patent application is currently assigned to Crystaphase Products, Inc.. The applicant listed for this patent is Crystaphase Products, Inc.. Invention is credited to BRADLEY GLOVER, JOHN N. GLOVER, PETER GREGORY HAM, AUSTIN SCHNEIDER.
Application Number | 20210187464 17/129488 |
Document ID | / |
Family ID | 1000005343287 |
Filed Date | 2021-06-24 |
United States Patent
Application |
20210187464 |
Kind Code |
A1 |
GLOVER; JOHN N. ; et
al. |
June 24, 2021 |
RESATURATION OF GAS INTO A LIQUID FEEDSTREAM
Abstract
A method for enabling gas exchange and chemical reactions with
one or more liquid streams contained in a reactive process vessel
are provided. One or more exchange layers within the process vessel
can be composed of both collector media and releaser media. The
exchange layers allow elements to facilitate increased performance
of vessel operations by promoting gas component mixing and
diffusion. Improved rates of gas component exchange mean less
coking and more gas components available for reaction.
Inventors: |
GLOVER; JOHN N.; (HOUSTON,
TX) ; GLOVER; BRADLEY; (HOUSTON, TX) ;
SCHNEIDER; AUSTIN; (HUMBLE, TX) ; HAM; PETER
GREGORY; (HOUSTON, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Crystaphase Products, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
Crystaphase Products, Inc.
HOUSTON
TX
|
Family ID: |
1000005343287 |
Appl. No.: |
17/129488 |
Filed: |
December 21, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62951681 |
Dec 20, 2019 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 2208/025 20130101;
B01J 2208/00274 20130101; B01J 2208/00283 20130101; B01J 8/0278
20130101 |
International
Class: |
B01J 8/02 20060101
B01J008/02 |
Claims
1. A method of treating a reactant-lean liquid phase in a process
vessel, comprising: passing the reactant-lean liquid phase and a
gas phase co-currently through an exchange layer in the process
vessel, wherein the gas phase comprises a reactant; and diffusing
at least some of the reactant from the gas phase into the
reactant-lean liquid phase in the exchange layer to form a
reactant-rich liquid phase, wherein the exchange layer comprises a
plurality of collector media and a plurality of releaser media, and
wherein the collector media comprise porous solid materials capable
of collecting the reactant-lean liquid phase within the collector
media, and wherein the releaser media comprise solid materials
having a thin film formed on an outer surface thereof that is
capable of facilitating contact and diffusion between the
reactant-lean liquid phase and the gas phase, and wherein the thin
film is formed on the releaser media during processing as a result
of liquid released from the collected liquid phase.
2. The method of claim 1, wherein the process vessel is a trickle
bed reactor.
3. The method of claim 1, further comprising passing the
reactant-rich liquid phase through a bed of porous solid elements
following the exchange layer, the porous solid elements comprising
at least one of catalysts, sorbents and reactants.
4. The method of claim 1, further comprising performing a treating
process in the process vessel to remove an undesired species from
the liquid phase, wherein the treating process comprises at least
one of hydro-desulfurization, hydro-denitrogenation,
hydro-cracking, hydrogenation, hydro-dearomatization,
hydro-deoxygenation, hydro-demetallization, and isomerization.
5. The method of claim 4, wherein the undesired species comprises
at least one of sulfur, nitrogen, oxygen, aromatics, olefins,
nickel, vanadium, iron, silicon or arsenic.
6. The method of claim 1, wherein the reactant-rich liquid phase
comprises at least one of naphtha, gasoline, kerosene, jet, diesel,
gas oils, vegetable oils, animal tallow, and liquid water.
7. The method of claim 1, wherein the reactant diffused from the
gas stream into the reactant-lean liquid stream comprises at least
one of methane, butane, propane, butalene, propylene, hydrogen,
ammonia, hydrogen sulfide, carbon dioxide, carbon monoxide, sulfur
oxides, nitrogen oxides, water gas, oxygen, and nitrogen.
8. The method of claim 1, wherein the releaser media comprise at
least one of catalysts, sorbents and reactants.
9. The method of claim 8, wherein the size of the releaser media is
no more than one-fourth the size of the collector media.
10. The method of claim 8, wherein each of the collector media in
the exchange layer has at least twenty contact points on its outer
surface that are contacted by releaser media.
11. A method of treating a product-rich liquid phase in a process
vessel, comprising: passing the product-rich liquid phase and a gas
phase co-currently through an exchange layer in the process vessel,
wherein the product-rich liquid phase comprises a reaction product;
and diffusing at least some of the reaction product from the
product-rich liquid phase into the gas in the exchange layer to
form a product-lean liquid phase, wherein the exchange layer
comprises a plurality of collector media and a plurality of
releaser media, and wherein the collector media comprise porous
solid materials capable of collecting the product-rich liquid phase
within the collector media, and wherein the releaser media comprise
solid materials which are capable of facilitating contact and
diffusion between the product-rich liquid phase and the gas phase,
and wherein the releaser media are no more than one-fourth the size
of the collector media, and wherein each of the collector media in
the exchange layer has at least twenty contact points on its outer
surface that are contacted by releaser media.
12. The method of claim 11, wherein the process vessel is a trickle
bed reactor.
13. The method of claim 11, further comprising passing the
product-lean liquid phase through a bed of porous solid elements
following the exchange layer, the porous solid elements comprising
at least one of catalysts, sorbents and reactants.
14. The method of claim 11, further comprising performing a
treating process in the process vessel to remove an undesired
species from the liquid phase, wherein the treating process
comprises at least one of hydro-desulfurization,
hydro-denitrogenation, hydro-cracking, hydrogenation,
hydro-dearomatization, hydro-deoxygenation, hydro-demetallization,
and isomerization.
15. The method of claim 14, wherein the undesired species comprises
at least one of sulfur, nitrogen, oxygen, aromatics, olefins,
nickel, vanadium, iron, silicon or arsenic.
16. The method of claim 11, wherein the product-lean liquid phase
comprises at least one of naphtha, gasoline, kerosene, jet, diesel,
gas oils, vegetable oils, animal tallow, and liquid water.
17. The method of claim 11, wherein the releaser media comprise at
least one of catalysts, sorbents and reactants.
18. A method of treating a reactant-lean, product-rich liquid phase
in a trickle bed process vessel, comprising: passing the
reactant-lean, product-rich liquid phase and a gas phase
co-currently through an exchange layer in the trickle bed process
vessel, wherein the gas phase comprises a reactant; and diffusing
at least some of the reaction products from the reactant-lean,
product-rich liquid phase into the gas phase and at least some of
the reactant from the gas phase into the reactant-lean,
product-rich liquid phase in the exchange layer to form a
reactant-rich, product-lean liquid phase, wherein the exchange
layer comprises a plurality of collector media and a plurality of
releaser media, and wherein the collector media comprise porous
solid materials capable of collecting the reactant-lean liquid
phase within the collector media, and wherein the releaser media
comprise solid materials having a thin film formed on an outer
surface thereof that is capable of facilitating contact and
diffusion between the reactant-lean, product-rich liquid phase and
the gas phase, and wherein the thin film is formed on the releaser
media during processing as a result of liquid released from the
collected liquid phase.
19. The method of claim 18, further comprising passing the
reactant-rich, product-lean liquid phase through a bed of porous
solid elements following the exchange layer, the porous solid
elements comprising at least one of catalysts, sorbents and
reactants.
20. The method of claim 18, further comprising performing a
treating process in the process vessel to remove an undesired
species from the liquid phase, wherein the treating process
comprises at least one of hydro-desulfurization,
hydro-denitrogenation, hydro-cracking, hydrogenation,
hydro-dearomatization, hydro-deoxygenation, hydro-demetallization,
and isomerization.
21. The method of claim 20, wherein the undesired species comprises
at least one of sulfur, nitrogen, oxygen, aromatics, olefins,
nickel, vanadium, iron, silicon or arsenic.
22. The method of claim 18, wherein the reactant-rich, product-lean
liquid phase comprises at least one of naphtha, gasoline, kerosene,
jet, diesel, gas oils, vegetable oils, animal tallow, and liquid
water.
23. The method of claim 18, wherein the reactant diffused from the
gas stream into the reactant-lean, product-rich liquid stream
comprises at least one of methane, butane, propane, butalene,
propylene, hydrogen, ammonia, hydrogen sulfide, carbon dioxide,
carbon monoxide, sulfur oxides, nitrogen oxides, water gas, oxygen,
and nitrogen.
24. The method of claim 18, wherein the releaser media comprise at
least one of catalysts, sorbents and reactants.
25. The method of claim 24, wherein the size of the releaser media
is no more than one-fourth the size of the collector media.
26. The method of claim 24, wherein each of the collector media in
the exchange layer has at least twenty contact points on its outer
surface that are contacted by releaser media.
27. A trickle bed process vessel for treatment of a reactant-lean,
product-rich liquid stream, comprising: an exchange layer
comprising a plurality of collector media and a plurality of
releaser media, wherein the exchange layer is capable of
facilitating diffusion of one or more reactants from a gas phase
into a reactant-lean, product-rich liquid phase within the exchange
layer to form a reactant-rich, product-lean liquid phase; and a
treatment layer downstream of the exchange layer comprising a bed
of porous solid elements, the porous solid elements comprising at
least one of catalysts, sorbents and reactants and capable of
performing a treating process to remove an undesired species from
the liquid phase, wherein the treating process comprises at least
one of hydro-desulfurization, hydro-denitrogenation,
hydro-cracking, hydrogenation, hydro-dearomatization,
hydro-deoxygenation, hydro-demetallization, and isomerization,
wherein the collector media and the releaser media are packed
within the exchange layer such that each of the collector media has
at least twenty contact points on its outer surface that are
contacted by releaser media, and wherein the gas phase and the
reactant-lean, product-rich liquid phase undergo co-current flow
within the exchange layer, and wherein the collector media comprise
porous solid materials capable of collecting the reactant-lean
liquid phase within the collector media, and wherein the releaser
media comprise solid materials having a thin film formed on an
outer surface thereof that is capable of facilitating contact and
diffusion between the reactant-lean, product-rich liquid phase and
the gas phase, and wherein the thin film is formed on the releaser
media during processing as a result of liquid released from the
collected liquid phase.
28. The process vessel of claim 27, wherein the releaser media
comprise at least one of catalysts, sorbents and reactants.
29. The process vessel of claim 27, wherein the size of the
releaser media is no more than one-fourth the size of the collector
media.
30. The process vessel of claim 27, wherein the undesired species
comprises at least one of sulfur, nitrogen, oxygen, aromatics,
olefins, nickel, vanadium, iron, silicon or arsenic, and wherein
the reactant-rich, product-lean liquid phase comprises at least one
of naphtha, gasoline, kerosene, jet, diesel, gas oils, vegetable
oils, animal tallow, and liquid water, and wherein the reactant
diffused from the gas stream into the reactant-lean, product-rich
liquid stream comprises at least one of methane, butane, propane,
butalene, propylene, hydrogen, ammonia, hydrogen sulfide, carbon
dioxide, carbon monoxide, sulfur oxides, nitrogen oxides, water
gas, oxygen, and nitrogen.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit, and priority benefit,
of U.S. Provisional Patent Application Ser. No. 62/951,681, filed
Dec. 20, 2019, the disclosure and contents of which are
incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The presently disclosed subject matter relates generally to
reactive process vessels, and more specifically, to enabling the
gas exchange and chemical reactions with one or more liquid streams
or phases contained in reactive process vessels.
2. Description of the Prior Art
[0003] Process vessels in the field are often vertical cylindrical
constructions with fluid streams or phases which enter, pass
through and exit such vessels. Industrial vessels are 6 inches to
over 20 feet in diameter and 2 to over 100 feet high. The vessels
containing reactive systems can be used to promote chemical
reactions.
[0004] Contained within many conventional vessels are different
phases of materials. A solid phase includes one or more beds of
solid elements. Other phases contained in vessels include fluid
phases including one or more liquid phases and one or more gas
phases. Multiple fluid phases can be contained in a fluid stream.
The state of the phases can depend on their operating conditions.
Typical liquid throughput to a vessel is measured in barrels per
day. Typical gas volumes are measured in standard cubic feet (SCF).
The throughput of gas to a vessel is typically measured in standard
cubic feet per barrel of liquid feed.
[0005] Improvements in this field are needed.
SUMMARY
[0006] In accordance with the presently disclosed subject matter,
various illustrative embodiments of a method for enabling the gas
exchange and chemical reactions with one or more liquid streams
contained in a reactive process vessel are provided herein.
[0007] In certain illustrative embodiments, a method of treating a
reactant-lean liquid phase in a process vessel is provided. The
reactant-lean liquid phase and a gas phase can be passed
co-currently through an exchange layer in the process vessel. The
gas phase comprises a reactant. At least some of the reactant from
the gas phase can be diffused into the reactant-lean liquid phase
in the exchange layer to form a reactant-rich liquid phase. The
exchange layer can include a plurality of collector media and a
plurality of releaser media, and the collector media can include
porous solid materials capable of collecting the reactant-lean
liquid phase within the collector media. The releaser media can
include solid materials having a thin film formed on an outer
surface thereof that is capable of facilitating contact and
diffusion between the reactant-lean liquid phase and the gas phase.
The thin film can be formed on the releaser media during processing
as a result of liquid released from the collected liquid phase. The
process vessel can be a trickle bed reactor. In certain aspects,
the reactant-rich liquid phase can be passed through a bed of
porous solid elements following the exchange layer. The porous
solid elements can include at least one of catalysts, sorbents and
reactants. A treating process can be performed in the process
vessel to remove an undesired species from the liquid phase. The
treating process can include at least one of hydro-desulfurization,
hydro-denitrogenation, hydro-cracking, hydrogenation,
hydro-dearomatization, hydro-deoxygenation, hydro-demetallization,
and isomerization. The undesired species can include at least one
of sulfur, nitrogen, oxygen, aromatics, olefins, nickel, vanadium,
iron, silicon or arsenic. The reactant-rich liquid phase can
include at least one of naphtha, gasoline, kerosene, jet, diesel,
gas oils, vegetable oils, animal tallow, and liquid water. The
reactant diffused from the gas stream into the reactant-lean liquid
stream can include at least one of methane, butane, propane,
butalene, propylene, hydrogen, ammonia, hydrogen sulfide, carbon
dioxide, carbon monoxide, sulfur oxides, nitrogen oxides, water
gas, oxygen, and nitrogen. The releaser media can include at least
one of catalysts, sorbents and reactants. In certain aspects, the
size of the releaser media can be no more than one-fourth the size
of the collector media. In certain aspects, each of the collector
media in the exchange layer can have at least twenty contact points
on its outer surface that are contacted by releaser media.
[0008] In certain illustrative embodiments, a method of treating a
product-rich liquid phase in a process vessel is also provided. The
product-rich liquid phase and a gas phase can be passed
co-currently through an exchange layer in the process vessel,
wherein the product-rich liquid phase can include a reaction
product. At least some of the reaction product from the
product-rich liquid phase can be diffused into the gas in the
exchange layer to form a product-lean liquid phase. The exchange
layer can include a plurality of collector media and a plurality of
releaser media, and wherein the collector media comprise porous
solid materials capable of collecting the product-rich liquid phase
within the collector media. The releaser media can include solid
materials that are capable of facilitating contact and diffusion
between the product-rich liquid phase and the gas phase. In certain
aspects, the size of the releaser media can be no more than
one-fourth the size of the collector media. In certain aspects,
each of the collector media in the exchange layer can have at least
twenty contact points on its outer surface that are contacted by
releaser media. The process vessel can be a trickle bed reactor. In
certain aspects, the product-lean liquid phase can be passed
through a bed of porous solid elements following the exchange
layer. The porous solid elements can include at least one of
catalysts, sorbents and reactants. A treating process can be
performed in the process vessel to remove an undesired species from
the liquid phase. The treating process can include at least one of
hydro-desulfurization, hydro-denitrogenation, hydro-cracking,
hydrogenation, hydro-dearomatization, hydro-deoxygenation,
hydro-demetallization, and isomerization. The undesired species can
include at least one of sulfur, nitrogen, oxygen, aromatics,
olefins, nickel, vanadium, iron, silicon or arsenic. The
product-lean liquid phase can include at least one of naphtha,
gasoline, kerosene, jet, diesel, gas oils, vegetable oils, animal
tallow, and liquid water. The releaser media can include at least
one of catalysts, sorbents and reactants.
[0009] In certain illustrative embodiments, a method of treating a
reactant-lean, product-rich liquid phase in a trickle bed process
vessel is also provided. A reactant-lean, product-rich liquid phase
and a gas phase can be passed co-currently through an exchange
layer in the trickle bed process vessel. The gas phase can include
a reactant. At least some of the reaction products from the
reactant-lean, product-rich liquid phase can be diffused into the
gas phase and at least some of the reactant from the gas phase can
be diffused into the reactant-lean, product-rich liquid phase in
the exchange layer to form a reactant-rich, product-lean liquid
phase. The exchange layer can include a plurality of collector
media and a plurality of releaser media. The collector media can
include porous solid materials capable of collecting the
reactant-lean liquid phase within the collector media. The releaser
media can include solid materials having a thin film formed on an
outer surface thereof that is capable of facilitating contact and
diffusion between the reactant-lean, product-rich liquid phase and
the gas phase. The thin film is can be formed on the releaser media
during processing as a result of liquid released from the collected
liquid phase. In certain aspects, the reactant-rich, product-lean
liquid phase can pass through a bed of porous solid elements
following the exchange layer. The porous solid elements can include
at least one of catalysts, sorbents and reactants. A treating
process can be performed in the process vessel to remove an
undesired species from the liquid phase, wherein the treating
process can include at least one of hydro-desulfurization,
hydro-denitrogenation, hydro-cracking, hydrogenation,
hydro-dearomatization, hydro-deoxygenation, hydro-demetallization,
and isomerization. The undesired species can include at least one
of sulfur, nitrogen, oxygen, aromatics, olefins, nickel, vanadium,
iron, silicon or arsenic. The reactant-rich, product-lean liquid
phase can include at least one of naphtha, gasoline, kerosene, jet,
diesel, gas oils, vegetable oils, animal tallow, and liquid water.
The reactant diffused from the gas stream into the reactant-lean,
product-rich liquid stream can include at least one of methane,
butane, propane, butalene, propylene, hydrogen, ammonia, hydrogen
sulfide, carbon dioxide, carbon monoxide, sulfur oxides, nitrogen
oxides, water gas, oxygen, and nitrogen. The releaser media can
include at least one of catalysts, sorbents and reactants. In
certain aspects, the size of the releaser media can be no more than
one-fourth the size of the collector media. In certain aspects,
each of the collector media in the exchange layer can have at least
twenty contact points on its outer surface that are contacted by
releaser media.
[0010] In certain illustrative embodiments, a trickle bed process
vessel for treatment of a reactant-lean, product-rich liquid stream
is provided. The process vessel can include an exchange layer
having a plurality of collector media and a plurality of releaser
media, wherein the exchange layer is capable of facilitating
diffusion of one or more reactants from a gas phase into a
reactant-lean, product-rich liquid phase within the exchange layer
to form a reactant-rich, product-lean liquid phase. The process
vessel can also include a treatment layer downstream of the
exchange layer having a bed of porous solid elements, the porous
solid elements having at least one of catalysts, sorbents and
reactants and capable of performing a treating process to remove an
undesired species from the liquid phase, wherein the treating
process can include at least one of hydro-desulfurization,
hydro-denitrogenation, hydro-cracking, hydrogenation,
hydro-dearomatization, hydro-deoxygenation, hydro-demetallization,
and isomerization. In certain aspects, the collector media and the
releaser media can be packed within the exchange layer such that
each of the collector media has at least twenty contact points on
its outer surface that are contacted by releaser media. The gas
phase and the reactant-lean, product-rich liquid phase can undergo
co-current flow within the exchange layer. The collector media can
include porous solid materials capable of collecting the
reactant-lean liquid phase within the collector media. The releaser
media can include solid materials having a thin film formed on an
outer surface thereof that is capable of facilitating contact and
diffusion between the reactant-lean, product-rich liquid phase and
the gas phase. The thin film can be formed on the releaser media
during processing as a result of liquid released from the collected
liquid phase. In certain aspects, the releaser media can include at
least one of catalysts, sorbents and reactants. In certain aspects,
the size of the releaser media can be no more than one-fourth the
size of the collector media. The undesired species can be at least
one of sulfur, nitrogen, oxygen, aromatics, olefins, nickel,
vanadium, iron, silicon or arsenic, and the reactant-rich,
product-lean liquid phase can be at least one of naphtha, gasoline,
kerosene, jet, diesel, gas oils, vegetable oils, animal tallow, and
liquid water, and the reactant diffused from the gas stream into
the reactant-lean, product-rich liquid stream can be at least one
of methane, butane, propane, butalene, propylene, hydrogen,
ammonia, hydrogen sulfide, carbon dioxide, carbon monoxide, sulfur
oxides, nitrogen oxides, water gas, oxygen, and nitrogen.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Some of the features and benefits of the present invention
having been stated, others will become apparent as the description
proceeds when taken in conjunction with the accompanying drawings,
in which:
[0012] FIG. 1 is a side view of process vessels having a plurality
of layers or zones in accordance with illustrative embodiments of
the presently disclosed subject matter.
[0013] FIG. 2 is a side view of process vessels having a plurality
of layers or zones in accordance with illustrative embodiments of
the presently disclosed subject matter.
[0014] FIG. 3A and FIG. 3B are comparison views of liquid and gas
co-current flow through an exchange layer and an exchange layer
spanning a bed in a process vessel in accordance with illustrative
embodiments of the presently disclosed subject matter.
[0015] FIG. 4 is a side view of an exchange layer in accordance
with an illustrative embodiment of the presently disclosed subject
matter.
[0016] FIG. 5A is a side view of collector media and releaser media
in accordance with an illustrative embodiment of the presently
disclosed subject matter.
[0017] FIG. 5B is a side view of collector media and releaser media
with thin film formed thereon in accordance with an illustrative
embodiment of the presently disclosed subject matter.
[0018] FIG. 6 is a side view of releaser media with thin film
formed thereon in accordance with an illustrative embodiment of the
presently disclosed subject matter.
[0019] FIG. 6A is a side view of releaser media with thin film
formed thereon and an active site in accordance with an
illustrative embodiment of the presently disclosed subject
matter.
[0020] FIG. 6B is a side view of releaser media with thin film
formed thereon in accordance with an illustrative embodiment of the
presently disclosed subject matter.
[0021] FIG. 6C is a side view of collector media and releaser media
with thin film formed thereon in accordance with an illustrative
embodiment of the presently disclosed subject matter.
[0022] FIG. 7 is a side view of filled collector media surrounded
by releaser media in accordance with an illustrative embodiment of
the presently disclosed subject matter.
[0023] FIG. 8 is a side view of partially filled collector media
surrounded by releaser media in accordance with an illustrative
embodiment of the presently disclosed subject matter.
[0024] FIG. 9 is a three dimensional perspective view of a
collector pane with a plurality of perforation holes in accordance
with an illustrative embodiment of the presently disclosed subject
matter.
[0025] FIG. 10 is a three dimensional perspective view of a
collector pane with a plurality of perforation holes in accordance
with an illustrative embodiment of the presently disclosed subject
matter.
[0026] FIG. 11 is a comparison view of a prior art process vessel
and a process vessel in accordance with an illustrative embodiment
of the presently disclosed subject matter.
[0027] FIG. 12 is a side view of a process vessel in accordance
with an illustrative embodiment of the presently disclosed subject
matter.
[0028] FIG. 13 is a side view of a stratified exchange layer in
accordance with an illustrative embodiment of the presently
disclosed subject matter.
[0029] FIG. 14A is a three dimensional view of releaser media
surrounding collector media in accordance with an illustrative
embodiment of the presently disclosed subject matter.
[0030] FIG. 14B is a three dimensional cross-sectional view of
releaser media surrounding collector media in accordance with an
illustrative embodiment of the presently disclosed subject
matter.
[0031] While the presently disclosed subject matter will be
described in connection with the preferred embodiment, it will be
understood that it is not intended to limit the presently disclosed
subject matter to that embodiment. On the contrary, it is intended
to cover all alternatives, modifications, and equivalents, as may
be included within the spirit and the scope of the presently
disclosed subject matter as defined by the appended claims.
DETAILED DESCRIPTION
[0032] In accordance with the presently disclosed subject matter,
various illustrative embodiments of a method for enabling the gas
exchange and chemical reactions with one or more liquid streams
contained in a reactive process vessel are provided herein.
[0033] In certain illustrative embodiments, as shown in FIGS. 1-14,
multi-phase reactions can occur within a process vessel 100. One or
more reactant-containing feed gas components can be diffused into
one or more feed liquids containing undesired species. These
diffused phases can be passed over one or more element beds 120
disposed in the vessel 100. The one or more diffused fluid phases
can be contacted with active sites 40 within the one or more
element beds 120 in the vessel 100. Active sites 40 typically
include one or more of catalyst sites, sorbent sites and reactant
sites.
[0034] Element beds 120 can contain one or more elements 125.
Elements 125 are typically porous solid materials. Elements 125 can
be non-porous solid materials. Elements 125 can be one or more of
catalysts, sorbents, and reactants. Elements 125 are typically
1/32'' to 1.5'' in size and can be packed in beds. Elements 125 can
contain or hold active features hereinafter called active sites 40.
Active sites 40 are one or more of catalyst sites, sorbent sites,
and reactant sites. The external surface area of elements 125 is
typically in the range of 100 to 800 square feet per cubic foot of
element beds 120.
[0035] As shown in FIG. 1, elements 125 in element beds 120 can all
be the same, or elements beds 120A, 120B, 120C etc, can have
different types or sizes of elements 125, or various combinations
thereof throughout vessel 100, according to various illustrative
embodiments.
[0036] Porous elements 125 can be comprised of micropores,
mesopores and/or macropores. Micropores have diameters less than 2
nanometers. Mesopores have diameters between 2 nanometers and 50
nanometers. Macropores have diameters larger than 50 nanometers.
Elements 125 can contain other porous features with diameters up to
300 nanometers. Under appropriate operating conditions, the element
beds 120 allow reactions to remove undesired species from the
diffused fluid, create species-free liquid product, and create
other products from the reaction between the gas-diluted phase and
the undesired liquid species.
[0037] In certain illustrative embodiments, components of the
presently disclosed subject matter can include one or more of:
element beds 120 containing active sites 40 disposed in the vessel
100; reactant-containing gas phases fed to the vessel 100;
undesired species-containing liquid phases fed to the vessel 100;
solutions of gas and liquid feed contacted with element beds 120;
species-free liquid products formed on the active sites 40; other
products formed on the active sites 40 from reaction of gas
components with undesired liquid species; remaining feed gas phases
recovered for recycle or subsequent processing; other products
recovered for subsequent processing; and liquid products free of
undesired species.
[0038] Efficient operation of vessel 100 relies on effective
mixing. For liquid and gas phase flows, mixing refers to any
operation used to combine the phases. Agitation is a common method
of mixing, which forces fluids to combine by mechanical means.
Mixing fluids increases diffusion or exchange of components between
them. Diffusion of fluid components is a well-known phenomenon.
Diffusion from a region of high concentration to one of low
concentration is defined by Ficks' laws, (see Adolph Ficks, 1855).
Ficks' laws state that high-concentration components present in a
fluid can diffuse into fluid containing little-to-no amounts of the
same components. Ficks' laws also state that the rate of change in
concentration of a component across a fluid-fluid boundary is
proportional to the surface area of that boundary. A reduction in
interfacial surface area between two phases can reduce the speed
with which one phase can diffuse into another.
[0039] In accordance with the presently disclosed subject matter,
it is desirable to have high interfacial surface area between the
liquid and gas phases at the interface of elements 125 in vessels
100 to create sufficient exchange between the phases. The gas
exchange is important to create conditions which are suitable for
desirable reactions.
[0040] A gas phase which partially dissolves into a liquid phase
creates a gas-liquid solution. The maximum amount of dissolved gas
in the liquid phase depends on the saturation limits. Higher
pressures and lower temperatures promote increased saturation
limits. Saturation is determined by the diffusion rate of the gas
into the liquid. The diffusion rate can have an influence on the
reaction kinetics which requires the simultaneous presence of
active sites 40, liquid reactants, and gas reactants to form
products. Reaction kinetics define the rate at which a particular
reaction occurs. Higher concentration of dissolved gas in the
liquid phase is desired in order to promote desired reactions.
[0041] In accordance with the presently disclosed subject matter,
high rates of diffusion can occur in vessels 100 when one or more
high-concentration gas phase components mix with one or more liquid
phase materials that contain little or none of the same components.
A liquid phase with a low concentration of dissolved, reactive gas
relative to the solubility limits can be called a "reactant-lean"
liquid phase. A liquid phase with a high concentration of
dissolved, reactive gas relative to the saturation limits can be
called a "reactant-rich" liquid phase. Reactant-lean liquid phases
can occur in the original liquid streams fed to the vessel 100 or
can be due to depletion of the one or more dissolved gases in the
one or more liquid phases during interaction with active sites 40.
Within a given process vessel 100, a reactant-rich liquid phase has
more gas-based reactant dissolved in the liquid phase when compared
to a reactant-lean liquid phase. Reactant-lean liquid phases are
less capable of producing a desired reaction compared to
reactant-rich liquid phases. One or more products can be created as
a result of reaction with active sites 40. Desirable reactions can
reduce undesired species by converting reactants within
reactant-rich liquid phases to products. Some of these products are
gases dissolved in the liquid phase. These dissolved gas products
are herein called "reaction products." Reaction products are
released from active sites 40 into the liquid phase. Reaction
products can exist as a solute in the liquid phase and can
interfere with reactions between gas phase reactant and undesired
species, resulting in a reduced rate of desirable reactions. A
liquid phase with higher concentrations of one or more reaction
products can be called a "product-rich" liquid phase. Where a
product-rich liquid phase forms, a concentration gradient of
reaction products can be developed between the liquid and gas
phases and diffusion of reaction products into the surrounding gas
phase can be promoted. Where a product-rich liquid phase forms,
desirable reaction rates can be reduced. It is desirable to remove
these reaction products from the liquid phase via gas exchange of
reaction products. Liquid phases with relatively low concentrations
of reaction products can be called a "product-lean" liquid phase.
Product-lean liquid phases can be more capable of producing a
desirable reaction compared to product-rich liquid phases because
less reaction products interfere with the reactions between
undesired species and dissolved gas reactants. Liquid phases can be
described as reactant-rich or reactant-lean and product-rich or
product-lean liquid phases.
[0042] In accordance with the presently disclosed subject matter,
one or more liquid phases fed to a vessel 100 contain undesired
species to be mitigated or converted within the process. One or
more gas components can be mixed with feed liquid phases by
diffusion and gas exchange. Exchanged gas feed can contain one or
more reactant components capable of mitigating the undesired
species in the liquid phase. Mitigation can be performed at and by
the active sites 40 contained in element beds 120. These active
sites 40 help to promote reactions to remove undesired species from
the liquid phase. As a result of the promoted reactions, reaction
products can be generated which become a part of the liquid and gas
flow of the vessel 100. In a conversion process where reactants,
including active sites 40 and fluid components, are freely
available to interact with each other, conversion can take place at
the speed of the molecular interaction between the reactants,
typically defined as the rate of reaction.
[0043] In traditional multiphase reactors, a number of steps must
proceed in order for the desired reaction to occur: one or more gas
and liquid phases must be supplied as feeds to the vessel; one or
more gas phase component reactants must diffuse into the one or
more liquid phase reactants; active sites 40 must be available to
undertake reaction; one or more diffused gas reactants and one or
more liquid phase reactants must react together at the active sites
40.
[0044] The reactor's overall rate of reaction will be limited to
the slowest rate in the steps described above. For many but not all
typical process vessels, the rate of diffusion of one or more gas
phase reactants into one or more liquid phase reactants is
typically the rate-limiting step. As described previously, Ficks'
laws dictate this rate of diffusion is dependent on the interfacial
surface area between the liquid phase and the gas phase. A reduced
rate of diffusion can be an impediment to process vessel
operation.
[0045] In accordance with the presently disclosed subject matter,
it is desirable to have an inter-fluid phase surface area for
element beds 120 within vessel 100 as large as possible to promote
diffusion rates. This can create reaction-rich, product-lean
liquids and will lead to higher reaction rates.
[0046] While introduced together, the one or more liquid and gas
phases can have varying velocities, temperatures, pressures, and
components in the vessel and within the bed of elements 120. The
flows of liquid phases through the element beds 120 are largely
driven by gravity while the gas phase flows are largely driven by
the pressure differential between the inlet and outlet of the
vessel. The gas phase can also experience a drag force due to
boundary conditions at the liquid-gas interface. The retarding
force on the gas phase can increase the amount of pressure
differential required to push the gas phase through the vessel and
its element beds 120. The liquid phase can feel an equal and
opposite force from the gas phase. The transportive forces on the
liquid phases are the sum of gravity and the drag force. As the
fluid phases move deeper into the bed or vessel, the liquid and gas
phases can attempt to arrange themselves in a way which minimizes
the pressure differential across the bed or vessel. This
arrangement tends to increase the separation of liquid and gas
phase volumes, which can reduce the interfacial surface area
between the two phases. Reduction of surface area and increase of
liquid-gas phase volume separation can continue and can grow as the
fluids move deeper into the bed or vessel.
[0047] In accordance with Ficks' laws, larger surface areas between
liquid and gas phases characterize well-mixed liquid and gas phases
as well as greater diffusion or exchange of molecules between the
phases. Smaller surface areas between liquid and gas phases can
characterize poorly mixed liquid and gas phases as well as lesser
diffusion or exchange of molecules between the two phases. The
reduction of liquid-gas surface interface can result in reduced
amounts of gas reactant moving into the liquid phase, limiting the
effectiveness of the element bed 120 or vessel 100. Reduced
diffusion between fluid phases can retard exchange between the
liquid and gas. This leads to reactant-rich, product-lean liquids
transitioning to reactant-lean, product-rich liquids as the phases
flow through the vessel. This is not a desirable transition.
[0048] There are many different vessel types. These can be regarded
as reactors, separators, guard vessels, or sorbent beds. In certain
illustrative embodiments a reactor is a type of trickle bed process
vessel. A large variety of treating processes exist in different
types of vessels. Many of these are hydro-treaters. Examples of
processes are hydro-desulfurization, hydro-denitrogenation,
hydro-cracking, hydrogenation, hydro-dearomatization,
hydro-deoxygenation, hydro-demetallization, isomerization, and
other industrial processes. Unit types in refining and
petrochemical applications can be naphtha hydro-treaters, PyGas
hydro-treaters, reformers, diesel hydro-treaters, gas oil
hydro-treaters, cat feed hydro-treaters, FCC Gasoline
hydro-treaters, FCC hydrogenation units, renewable diesel
hydro-treaters, fixed-bed transesterification vessels,
hydro-cracker pre-treaters, hydro-crackers, isomerization units,
kerosene hydro-treaters, jet hydro-treaters, lube oil
hydro-treaters, de-waxing units, resid hydro-treaters, dryers,
chloride treaters, clay treaters, salt dryers, and other fixed bed
units.
[0049] Liquid streams can be organic or inorganic. Common liquid
phases include vegetable oils, animal tallow, water, hydrocarbons,
crude oil and derivatives of crude oil such as naphtha, gasoline,
kerosene, jet, diesel, gas oil, or other crude oil derivatives.
Common gas phases include methane, butane, propane, hydrogen,
ammonia, hydrogen sulfide, hydrogen chloride, carbon dioxide,
carbon monoxide, sulfur oxides, nitrogen oxides, water, oxygen,
nitrogen, or other gases. Gases can also be mixtures. Common
reaction products include treated hydrocarbon, hydrogen, ammonia,
hydrogen sulfide, carbon dioxide, carbon monoxide, water, and other
gases.
[0050] A widely-used example of a multi-phase vessel is a
hydro-treating vessel feeding both a liquid hydrocarbon, or oil,
phase containing various undesired sulfur species and a gas phase
containing hydrogen. These phases are passed over active sites 40
contained in element beds 120. A desirable reaction of
hydro-treaters can be to react the hydrogen gas phase with the
undesirable sulfur species in the oil phase at the active site 40.
The desirable reaction produces a sulfur-free hydrocarbon and
hydrogen sulfide. The hydrogen sulfide is a reaction product,
dissolved in the liquid phase. In this example, as the desirable
reaction is repeated, hydrogen can be depleted from the liquid
phase and hydrogen sulfide can build up in the liquid phase. Gas
exchange is desired to increase the concentration of dissolved
hydrogen gas in the liquid oil phase and simultaneously reduce the
dissolved hydrogen sulfide gas from the liquid oil phase, as shown
in FIG. 6B. The gas exchange depends on the interfacial surface
area between the liquid oil phase and the gas phase. The more
thoroughly mixed the phases, the higher the surface area between
them resulting in a higher rate of gas exchange. A high degree of
mixing is desirable. Example hydro-treaters typically operate as
trickle bed reactors having temperatures ranging between 200 and
800 degrees Fahrenheit and pressures ranging between 200 and 2,000
psi. Trickle bed reactors are multiphase reactors that contain
fixed beds of solid elements and fluid phases that flow
co-currently through the reactor.
[0051] Henry's Law (see William Henry, 1803) states that the mass
of a dissolved gas in a given volume of solvent at equilibrium is
proportional to the partial pressure of the gas. In the
conventional hydro-treating example, to counteract the loss of
liquid-gas surface interface and to encourage the diffusion of
hydrogen into the oil, hydrogen must be present in flow rates 3 to
5 times larger than the flow rate of oil entering the vessel 100.
If 200 standard cubic feet of hydrogen per barrel of oil are
required for conversion, 600 to 1000 standard cubic feet of
hydrogen per barrel of oil needs to be fed to and circulated within
the vessel 100. The fluid feed phases are mixed at points of
introduction into the vessel 100 or beds 120 by hardware known as
mixers, quenches, and/or distributor trays to allow gaseous
hydrogen diffusion into the oil. Depending on vessel 100 pressure,
temperature, and hydrogen purity, the maximum solubility of
hydrogen in the oil is between 50 and 100 standard cubic feet per
barrel of oil. The hydrogen and sulfur species in the diffused oil
phase can interact with the active sites 40 to perform the desired
desulfurization reactions. These reactions create hydrogen sulfide
as a recoverable by-product. Below the hardware known as mixers,
quenches, and/or distributor trays, and above the element beds 120,
top bed material 170 can be used for capabilities comprising
filtration, distribution, and/or hold down.
[0052] A trickle bed reactor is a multi-phase vessel 100
configuration. The co-current flows of liquid and gas through the
reactor allow interaction of gas components with the liquid phase.
Element beds 120 installed in the vessel 100 can provide new and
surprising advantageous reactor performance including improvements
in gas phase diffusion, reaction effectiveness, hydrogen
utilization and reaction product production and recovery. When
element beds 120 are packed into a trickle bed vessel, they have a
packing efficiency and coordination number. Packing efficiency is
defined as the volume percent of a space occupied by an element bed
120. The coordination number is the number of contact points any
element 125 has with the elements 125 that surround it. In general,
as the packing efficiency increases so does the coordination
number. The Kepler Conjecture (see Johannes Kepler, 1611) states
that no arrangement of equally sized spheres filling space has a
greater average density than that of the "cubic close packing." The
cubic close packing is a highly ordered state and unlikely to be
achieved unless spheres are placed by hand. The coordination number
for cubic close packing of spheres is 12. The loading process in
these vessels 100 is largely random, but can be controlled to vary
the degree of packing efficiency and contact points between
elements 125. Highly ordered close packing is not probable in these
loadings and coordination numbers can be less than the maximum. It
is desired to increase the packing efficiency to have as many
elements 125 as possible in the vessel 100. However, hydrodynamic
constraints, e.g., differential pressure between phases, can limit
the allowed packing efficiency. The depths of the loading can be
anywhere from approximately a few inches to 100 feet. These are
conventionally loaded as one element bed 120, with elements 125 of
varying shapes and sizes, but are typically similarly loaded.
Deeper element beds 120 are generally used to add cycle time and to
improve the conversion which can be achieved during operation.
Diffusion of gas phase materials into the flowing liquid phase
material can depend on the rate of diffusion as determined by
elemental composition plus vessel 100 temperature, pressure and
boundary layer issues governing the contact of gas and liquid
species.
[0053] Liquid and gas phase flows will have superficial velocities
defined by the volumetric flow rate of these phases divided by the
cross-sectional area of the process vessel 100. Actual liquid and
gas phase flow velocities can have local velocity variations which
range from near zero to over four times the calculated superficial
liquid flow velocity. Additionally, density differences between
liquid and gas phases exist. In part, this is what can lead to
liquid and gas phase separation and reduced interfacial surface
area between the phases.
[0054] "Liquid hold up" is a portion of the volume within the
interstitial spaces between the elements 125. Liquid hold up can
occur wherever the interstitial liquid flow velocity is zero or
near zero. Liquid flow volume can be considered stagnant in these
parts of the element bed 120. Typical liquid hold up in element
beds 120 is in the range of 20%-40% of the interstitial space
between the elements 125 and occurs in locations where the elements
125 are touching one another.
[0055] When element beds 120 are packed or loaded, they can be
randomly packed and not in a highly ordered state. In this randomly
packed state approximately 12 or less elements 125 contact any
single element 125. The number of contact points can limit the
pathways liquid can take between elements 125.
[0056] Important properties related to the behavior of liquid and
gas phase flow in a trickle bed reactor are determined by the
properties of the element beds 120 themselves. These properties are
packing efficiency, void space diameter, and liquid hold up volume.
Packing efficiency is defined as the percent of the element beds
120 which fill a given space. Typical packing efficiencies for
element beds 120 are in the range of 55% to 65%. Typical space not
filled by element beds 120 is, therefore, 35% to 45%. This space is
herein called "void space." Higher packing efficiency allows for
higher mass loadings of elements 125 into the vessel:
void space %=100%-packing efficiency %
[0057] The void space in the element bed 120 also affects the range
of liquid hold up the element beds 120 can achieve. With the
packing efficiencies described, liquid hold up can be in the range
of 7%-18% of the element bed 120 volume.
[0058] Void space diameter can be taken as the average size of the
void spaces which are developed by packing the element beds 120.
One way to characterize the expected void space diameter of a
packed element bed 120 is to use hydraulic diameter. Hydraulic
diameter is defined by:
D h = 4 1 - p p D e 6 p ##EQU00001##
[0059] Where D.sub.h is hydraulic diameter, D.sub.e is the nominal
diameter of the elements 125, and p is the packing efficiency. For
an element bed 120 of nominally 1/8 inch (3.17 mm) sized elements
125 with a packing efficiency of 60%, the hydraulic diameter is
2.34 mm or about .about.73% of the element 125 diameter. For an
element bed 120 of nominally sized 1/20 inch (1.27 mm) sized
elements 125 with a packing efficiency of 60%, the hydraulic
diameter is 0.94 mm, which is again .about.73% of the element 125
diameter. The hydraulic diameter can be taken as an approximate
estimation of the average diameter of the void space between
elements 125, called the void space diameter.
[0060] Liquid hold up volume can be related to void space diameter
and packing efficiency. Void space diameter controls the efficacy
of liquid hold up with smaller void space diameters allowing a
higher liquid hold up. Packing efficiency can also influence the
amount of liquid hold up. The higher the packing efficiency, the
lower the total liquid hold up. As the void space diameter shrinks,
the liquid hold up in the void space can become driven by capillary
action (see Leonardo da Vinci, c. 1500, see Robert Boyle, 1660).
Capillary action occurs when the adhesion to the surfaces of a
material is stronger than the cohesive forces between the liquid
molecules or even the transportive forces on the liquid molecules.
The surface tension between the liquid and solid acts to hold the
surface intact. In the case of porous beds and porous bodies,
adhesion of liquid to the surfaces of materials can cause a force
on the liquid which acts to keep the liquid in contact with the
solid. Due to these, capillary action can increase the liquid hold
up of material. Materials with high capillary action typically have
high surface area to volume ratios.
[0061] While higher liquid hold up improves the surface area and
contact between the fluid phases and solid Elements, this is
typically an undesirable property in trickle bed processing where
intimate contact between liquid and gas phases components is
important. Small void space diameters can drive up liquid hold up
while eliminating void space available for gas flow. It is more
advantageous to have trickle bed properties which allow for thin
films 35 across the elements 125 in order to maximize the
interaction between the liquid and the gas. A typical "thin film"
35 is comprised of a region of liquid phase partially bound by a
solid phase with a free surface where the liquid phase is exposed
to a gas phase and the liquid phase travels on the surface of the
solid phase. Small void space diameters can encourage liquid hold
up and, in the case of elements 125, contribute to the collapse of
thin films 35. It is desirable for a trickle bed reactor to sustain
thin films 35. The gas is then able to flow over and interact with
the thin film 35 of liquid. Thin films 35 advantageously lead to
higher liquid surface areas with higher liquid-gas interface
enabling gas exchange and, therefore, availability for reaction
with elements 125. But as discussed above, conventional trickle bed
reactor thin films 35 are typically not hydro-dynamically stable
and can eventually collapse. Due to this instability, high
liquid-gas interface surface area is difficult to achieve and
maintain.
[0062] One advantageous method to overcome the necessity of high
liquid-gas interaction is to provide the ability to pre-mix and
then distribute the liquid and gas onto the element bed 120.
Conventional vessels can provide initial mixing of the fluid phases
by using "fabricated engineered mixer equipment" or "distributor
trays" installed to facilitate mixing and distribution of fluid
phases. This can also be accomplished by way of one or more
fabricated engineered distribution trays or vapor phase mixers
installed downstream of vapor injection. Such engineered mixer
equipment is typically used to promote diffusion of hydrogen into
oil, creating a reactant-rich liquid. Engineered mixer equipment
can be complex, difficult and expensive to design, fabricate,
install, operate and maintain. Installation, operation and
maintenance requires that the equipment is secured and aligned to
be perpendicular to the flow of streams within the vessel 100.
Additionally, the installation of such devices can take up 3 to 10
feet of vessel 100 depth, space where there are typically no
elements 125 installed. A properly installed and operated
distributor tray can provide a high degree of initial bed wetting
and good liquid-gas-solid interaction at the top of the element bed
120. Improperly installed and operated distributor tray can ensure
poor bed-wetting and top bed 170 interaction. Such devices
including trays and quench nozzles can be installed in the middle
of the vessel 100.
[0063] This high liquid-gas surface area provided at the top of the
element bed 120 becomes reduced as the fluid phases go deeper into
the element bed 120. Regions of limited to no interaction between
liquid and gas phases take shape. This low interaction creates
undesirable regions of reduced liquid-gas surface interface,
decreasing the diffusion rate between the two fluid phases. The
decreased diffusion rates can lead to reactant starvation. Reactant
starvation develops where one or more gas reactant components are
consumed in the diffused fluid state faster than they can be
replenished from the surrounding gas phase. The reduced diffusion
leads to the development of a reactant-lean liquid. The growing
presence of liquid-gas separation and reactant starvation can:
increase the hydrogen flow rate required to sustain gas exchange;
decrease the effectiveness of the element beds 120; reduce overall
vessel 100 performance due to a reduction in desired reactions; and
increase the presence of coking reactions.
[0064] In trickle bed vessels 100, one or more desired gas
components can be depleted from the liquid phase due to reaction
between: undesired liquid species reactants, diffused gas phase
reactants, and active sites 40.
[0065] Reaction products accumulate in the diffused liquid phase as
a result of the same reactions leading to a product-rich liquid.
For efficient reaction, one or more desired gas phase reactant
components must be replenished into the one or more diffused liquid
phases and the one or more reaction products removed from the
diffused liquid phases. It is desirable for the reactant-lean,
product-rich liquid to transition to a reactant-rich, product-lean
liquid. The separation of liquid and gas phases caused by
deterioration of the trickle bed reactor performance reduces the
surface area between the phases and disables these functions. This
can result in reduced reaction kinetics because the desired gas
phase reactants are not available for reaction and the reaction
products remain dissolved in the fluid and interfere with the
desired reactions between reactants.
[0066] In the hydro-treating example, if the hydrogen reactant
becomes limited, other reactions can take place in the absence of
hydrogen. In general, these other reactions are referred to as
coking and can cause harm to the effectiveness of the element bed
120. Coking takes several forms, each form resulting in a buildup
of difficult species that can block active sites 40 on the element
beds 120.
[0067] Coking occurs due to molecular cracking, olefinic
polymerization, and aromatic polymerization. Aromatic
polymerization refers to the growth of polycyclic aromatic
compounds. Once these molecules grow large enough they are able to
deposit on the surface of active sites 40. These are undesired
products. Olefinic polymerization refers to the growth of
unsaturated paraffin compounds. These grow to be large and block
active sites 40. Molecular cracking refers to the continual
breaking of hydrocarbon chains. As these chains are broken, if
hydrogen is not present in sufficient amounts, unsaturated
molecules are formed and active sites 40 are blocked. Coking is a
major contributor to element bed 120 deactivation and can lead to
the "death" of the active sites 40, requiring the vessel 100 to be
shut down and the elements 125 to be removed and/or exchanged. It
is desirable to reduce the deactivation rate caused by coking.
[0068] The performance of reactions in the one or more conventional
element beds 120 can change with the depth of the beds. At the top
of the upper-most element bed 120, near the properly installed,
operated and maintained engineered mixer equipment 190, trickle bed
reactor performance is high and coking reaction rates may be
minimal. As the fluid phase goes deeper into the bed, element bed
120 performance deteriorates: the surface area between the liquid
phase and gas phase decreases, the dissolved gas in the liquid is
consumed, reactant starvation ensues, the coking reaction rates can
increase, and the active site 40 performance drops. The higher the
concentration of undesirable species in the liquid phase, the
faster reaction starvation can develop. In the case of a
hydro-treater intended to remove sulfur species, the overall lower
rates of desired reactions result in higher product sulfur content,
higher operating temperature, and shorter cycle lengths.
[0069] Processing conditions can be adjusted to respond to element
bed 120 deactivation to keep the processing vessel 100 producing
desirable reactions. Responses to element bed 120 deactivation can
require increased element bed 120 temperature and/or reduction in
element bed 120 feed rate. Increase in temperature serves to
increase reaction rate in the vessel 100 to make up for lost
activity. Reduction in feed rate reduces the required reaction
rate. Continued adjustments or responses will fail as temperature
increase eventually will exceed vessel 100 operating constraints
and feed rate reduction results in economically unfavorable
operation. Steps taken at this point include vessel 100 shutdown
and steps to make element bed 120 replacement.
[0070] Disclosed are novel effects which increase the rate of gas
exchange, done by exchange layers 140, into and out of two or more
fluid phase components in one or more vessels 100 containing one or
more element beds 120 which facilitate conversion between the
reactants contained in the fluid phases. Steps which create these
include one or more: vessels 100 equipped with improved exchanged
gas facilities; diffused fluid phases with improved interactions;
exchange layers 140 which improve reactant replenishment via thin
film 35 diffusion; reduced uncontaminated active sites, including
coke, contained in element beds 120; and reaction products escaping
the reaction zone quickly and efficiently.
[0071] Increased reactant-rich liquid phases remove gas exchange
limitations and can increase the element bed 120 reaction rate.
Both of these improvements can lead to benefits such as lower
operating temperature, increased throughput, and reduced gas
circulation. Improved availability of the gas phase components in
the liquid phase can also serve to reduce the rate of a harmful
side reaction, like coke formation, on or in the element beds 120.
This helps mitigate one of the most common causes for vessel 100
shutdown and increases the capability of an element bed 120 to
perform its desired reactions.
[0072] Additional disclosed benefits from improving gas exchange
would be the ability to achieve higher conversion rates for a
constant set of operating conditions (e.g. temperature, pressure,
and feed rate). For similar inlet concentrations of undesired
liquid species at constant operating conditions, improved gas
exchange would provide lower concentrations of undesired species in
the product phases of such a vessel 100.
[0073] The use of exchange layers 140 can have surprising and
unexpected results. Such results can have positive impacts on the
operation of a processing vessel. Exchange layers 140 which enable
a low rate of coke formation can result in a more constant or
nearly constant inlet temperature over time. Since the inlet
temperature is not being raised, the process vessel 100 is able to
operate for a longer period of time or process more feed before a
shutdown is required. Furthermore, operating at lower temperatures
also enables improved rates of aromatic saturation and exchange
layers 140 could be useful in helping to improve aromatic
saturation on the basis of both hydrogen availability and a
reduction in operating temperature. Even further, exchange layers
140 can enable conversion of compounds which can require multiple
steps to remove the undesired species. As an example, some sulfur
species are known as "hindered", where aromatic rings block the
removal of the hindered sulfur from the hydrocarbon. The aromatic
ring must first undergo a saturation reaction to become a
naphthene, followed by the sulfur removal step. The aromatic
saturation step unblocks the sulfur molecule and both reactions
must proceed in order, otherwise the naphthene can convert back to
an aromatic, once again hindering the sulfur removal.
[0074] Another surprising and unexpected result of using an
exchange layer 140 would be a reduced amount of carbon build up on
elements 125 at or below the level of the exchange layer 140. In
element beds 120 where hydrogen consumption is high, once the
liquid phase becomes a "reactant-lean" liquid phase, coking
formations take place and deposit carbon on the elements 125. The
buildup of carbon harms the process vessel operation and can make
it difficult to unload the elements 125 from the process vessel
100. The carbon build up fuses the elements together 125 making
unloading difficult. Use of exchange layers 140 at these locations
can reduce carbon deposition. In place of coking, desired reactions
can occur. This result could be observed during the unloading of
such a process vessel 100. The elements above the exchange would be
filled with carbon and be fused together, where the exchange layer
140 and the element bed 120 below it would have reduced amounts of
carbon and the elements 125 would be free flowing.
[0075] In certain illustrative embodiments, as shown in FIG. 1 and
FIG. 2, vessel 100 can include one or more exchange layers 140
containing media which can facilitate gas exchange between fluid
phases in the vessel 100. Vessels 100 can be one vessel or multiple
vessels functioning together. Exchange layers 140 can avoid
starvation of fluid reactants. Exchange layers 140 can
advantageously facilitate the production of reactant-rich,
product-lean liquid phases. In certain illustrative embodiments,
the performance of exchange layers 140 can be dependent on the
location and depth of the media, the size and structure of the
media, the surface area of the media, the positions of the media
and/or the positions and compositions of the fluid phases in the
vessel 100. Exchange layers 140 can be positioned relative to
element beds 120. Exchange layers 140 can be positioned upstream of
element beds 120 to facilitate the diffusion of fluid phases
entering the element beds 120. Exchange layers 140 can also be
positioned downstream of element beds 120 to facilitate diffusion
of fluid phases for processing in downstream element beds 120.
Exchange layers 140 can be installed along with distributor trays
and/or injection ports that may also be in the vessel. Exchange
layers 140 can be installed below top bed 170 material prior to
entry into the element bed 120 or can also be installed at the top
of a bed within vessel 100. Exchange layers 140 can, but do not
need to, span the diameter of the vessel 100. Exchange layers 140
could be pocketed throughout the vessel 100, whereby they do not
span the diameter of the vessel 100, but still provide
functionality in the region where they do exist.
[0076] In certain illustrative embodiments, the disclosed media in
exchange layers 140 can include one or more zones containing
collector media 20 and one or more zones containing releaser media
30. The interaction of these media with the liquid and gas phases
helps to advantageously facilitate the exchange of liquid and gas
phase components in the vessel 100. As illustrated in FIG. 3A, the
collector media 20 and the releaser media 30 can enable gas
exchange for co-current flow of the phases within exchange layer
140. As illustrated in FIG. 3B, the collector media 20 and the
releaser media 30 can enable gas exchange and act as a treating bed
for co-current flow within exchange layer 140. In certain
illustrative embodiments, collector media 20 utilize liquid hold up
and capillary action to facilitate one or more processes occurring
within vessel 100. This can occur within exchange layer 140,
whereby the liquid hold up is increased for a given region of
volume within one or more collection zones 22 of collector media
20. The collection zones 22 provide a localized region in collector
media 40 where the flowing liquid phase can be collected or held,
hereinafter "liquid collection". Once liquid collection is
maximized within the collection zone 22, any addition of liquid
volume can cause an outflow of liquid from that region. Collector
media 20 can be shaped so as to maximize or minimize the size of
the liquid collection region in collection zone 22 and allow the
outflow of liquid from the liquid collection 22. The filled liquid
collection 22 also allows gas phase flows to bypass the collector
media 20 and interact with the downstream releaser media 30.
[0077] The presently disclosed subject matter provides surprising
and unexpected results as compared to previously used technologies.
The described liquid hold up can be detrimental to process vessel
operation due to the inherent forces which promote separation of
liquid and gas phases.
[0078] In certain illustrative embodiments, exchange layers 140
avoid this problem by creating a region of high surface area by
providing collector media 20 and high surface area releaser media
30 adjacent to and surrounding the collector media 20, as shown in
the illustrative embodiments of FIG. 4 and FIG. 5A. This region
enables the outflow of liquid from collector media 20. Capillary
action can draw and hold liquids into collector media 20. Collector
media 20 facilitated by liquid hold up and capillary forces deliver
uniform liquid flow across the region of high surface area.
[0079] In certain illustrated embodiments, the volume flow of
liquid onto releaser media 30, a high surface area solid, enables
formation of a thin film 35 on an outer surface of releaser media
30, as shown in FIG. 6, which enhances the mixing of liquid in the
thin film 35 and gas passing over the thin film 35. This enhanced
mixing and this surface area can enables exchange of gas phase
components into the liquid phase, creating reactant-rich liquid
phases. This enhanced mixing and this surface area enables
dissolution of undesired gas phase components out of the liquid
phase, creating product-lean liquid phases. Generating this high
surface area surrounding collector media 20 and enabling outflow of
liquid with thin film 35 formation is a function of releaser media
30, in certain illustrative embodiments.
[0080] In certain illustrative embodiments, collector media 20 and
releaser media 30 can be high geometric surface area media,
including porous media. Porous media are defined as a solid with
pores which enter into and/or through the media. The porous media
can include reticulates, honeycomb monoliths, macro-porous
materials, fissured material, agglomerates of particle packing, and
fibrous mesh. These porous media can be shaped as spheres,
cylinders, rings, briquettes, ellipsoids, prisms, cubes,
parallelepipeds, ortho-topes, saddles, wagon wheels, medallions,
lobed extrudates and the like. Porous media can have surface
features including asperities such as polyps, fibrils, filaments,
hairs, ridges, lobes, troughs, fins, and the like. Porous media can
be metallic, ceramic, polymeric or combinations of these. Porous
media can be oxides, nitrides, carbides or the like.
[0081] In certain illustrative embodiments, active sites 40 can be
added to releaser media 30. In certain illustrative embodiments,
releaser media 30 can be elements 125. In certain illustrative
embodiments, releaser media 30 can be inert. In certain
illustrative embodiments, collector media 20 can be converted into
elements 125 by adding active sites 40 to the collector media 20.
In certain illustrative embodiments, collector media 20 can be
inert.
[0082] In certain illustrative embodiments, collector media 20 are
capable of containing or holding liquid phases. Collector media 20
can have individual sizes ranging between 12 and 200 millimeters.
Collector media 20 can have pore pathways having diameters ranging
from 1 micron to 20 millimeters. The collector media 20 internal
void space, composed of the pore pathways, can make up 20% to 95%
of the volume of the collector media 20. Collector media 20 can
have internal void space that ranges from 100 to 6,000 square feet
per cubic foot of collector media 20. Within the exchange layer
140, collector media 20 can be packed to achieve 30% to 70% packing
efficiency. By controlling the pore sizes, collector media 20 can
achieve up to 100% liquid collection in their internal void space.
Liquid collection can be determined by multiplying the packing
efficiency and the internal void space. For the packing efficiency
and internal void space described, collector media 20 liquid
collection can be in the range of 6%-66.5% of the exchange layer
140 volume. This range provides the ability to control liquid
collection to a much greater degree. A preferred amount of liquid
collection would be in the range of 20% to 66.5% of the exchange
layer 140 volume, surpassing the liquid hold up of previously
mentioned elements 125. This can be achieved by any combination of
the packing efficiency and internal void space described.
[0083] In certain illustrative embodiments, collector media 20 can
disperse liquid phases within vessel 100 to releaser media 30. For
example, when the collector media 20 are completely filled with
liquid, gas phase phases can bypass collector media 20. In other
illustrative embodiments, the collector media 20 are partially
filled with liquid, gas phases can move through collector media 20,
co-current with the liquid phase.
[0084] In certain illustrative embodiments, releaser media 30 can
receive liquid release from the collector media 20. Releaser media
30 can have an interstitial void space, defined by the volume
consumed by pore pathways, which is permeable to the gas phase
fluids. Coupled with formation of the thin film 35 as a liquid on
the releaser media 30, gas flow in the interstitial void spaces can
create an opportunity for a high degree of mixing and liquid-gas
exchange on the thin film 35, improving gas exchange. Releaser
media 30 can be equal to or smaller than the size of the collector
media 20 they surround, to fit into the space created by the
collector media 20. In certain illustrative embodiments, the
releaser media 30 sizing would be 1/32'' to 1/2''. Releaser media
30 can be the same shape or a different shape than collector media
20. In certain illustrative embodiments, releaser media 30 can have
as many touch points as possible for liquid release from the
collector media 20 to the neighboring releaser media 30. This can
be done by choosing releaser media 30 sizing small enough to
increase contact points and surface area, but large enough that
both liquid and gas phase are able to flow co-currently through the
space surrounding the releaser media 30 and across the thin film 35
surfaces of the releaser media 30. Additionally, the shape of the
releaser media 30 will influence the surface area and void space
shape.
[0085] In certain illustrative embodiments, releaser media 30 can
have sizes ranging from 800 microns to 12.7 millimeters. Releaser
media 30 can have geometric surface areas ranging from 60 to 1000
square feet per cubic foot of releaser media 30. Releaser media 30
can also be packed within the spaces between the larger collector
media 20 so as to surround the collector media 20. Releaser media
30 can achieve a packing efficiency of >50% within the spaces
surrounding the collector media 20. Contact areas between releaser
media 30 and collector media 20 can act as release points to
receive liquid from neighboring collector media 20. It is desirable
to have packing that achieves the greatest number of releaser media
30 contact release points on the collector media 20 outer surface.
In one preferred embodiment releaser media 30 can have sizing from
1/14th to 1/4th the size of collector media 20. In certain other
illustrative embodiments releaser media 30 can have sizing less
than 1/14th the size of collector media 20. In yet another
illustrative embodiment releaser media 30 can have sizing greater
than 1/4th the size of collector media 20. Also, at least twenty
contact points are desired between each collector media 20 and the
releaser media 30, in certain illustrative embodiments. For
example, FIG. 14A is a three dimensional view and FIG. 14B is a
three dimensional cross-sectional view of releaser media 30
surrounding collector media 20 in a manner that would provide at
least twenty contact points therebetween. Due to the nature of low
volume outflow and the described high surface area available for
the liquid phase phases exiting the collector media 20, the liquid
can travel along the releaser media 30 as thin films 35. Releaser
media 30 have exposure to gas phases to encourage the diffusion of
gas components into the liquid due to these thin films 35. During
contact with the releaser media 30, the amount of gas exchanged
into the thin film 35 liquid phase can be increased due to the
higher rate of diffusion caused by the thin film 35 high surface
area.
[0086] Collector media 20 and releaser media 30 work together in
order to improve the liquid-gas interfacial surface area. For
certain pore sizes within the collector media 20, liquid hold up
and capillary forces can develop, providing liquid collection
within the media. At maximum liquid collection, excess liquid is
released from the collector media 20 to the releaser media 30 where
gas exchange is provided through the releaser media 30.
[0087] Conventional element beds 120 without exchange layers 140
can provide a high surface area structure, but can lack the
stability to generate sustained thin film 35 conditions. Hence, the
trickle bed flow regime devolves into a low liquid-gas surface
interface area, disabling high interaction between the liquid and
gas phases. Disclosed collector media 20 provide void space for a
high volume of liquid collection, a small pore size for a capillary
force to slow liquid flow and can allow liquid accumulation, and
can be permeable enough to provide organized release of liquid onto
the releaser media 30.
[0088] In certain illustrative embodiments, the pore sizes of a
collector media 20 are less than the size of an individual releaser
media 30 to keep the releaser media 30 out of the internal
structure of the collector media 20. In a preferred illustrative
embodiment, collector media pore sizes are less than the void space
diameter of releaser media 30 to encourage liquid collection in the
collector media 20 and allow liquid outflow onto the releaser media
30.
[0089] In certain illustrative embodiments, the collector media 20
have pore volume within their bodies. The pore volume is of a pore
size which is permeable to liquid phases, but is smaller than the
void space diameter of the surrounding releaser media 30. As a
result, collector media 20 can have a higher liquid collection
capability than that of the surrounding releaser media 30. As the
collector media 20 reach their maximum liquid collection, as
determined by the internal void space of the collector media 20,
the filled collector media 20 will release liquid in the direction
of gravity. The collected liquid can be preferentially released to
any downstream media (i.e., releaser media 30) which is contacting
the downstream surface of the upstream media (i.e., collector media
20) at as many interface points as possible. This can create an
opportunity for release of liquid to the neighboring packed bed of
releaser media 30.
[0090] In certain illustrative embodiments, this releases thin
films 35 with high surface area to develop on the surface of the
releaser media 30. As provided by Ficks' laws, the higher surface
area of the thin films 35 will enable improved transfer rate
between the liquid and gas phases. As a result, desired feed stream
gas components, continually depleted in the diffused liquid phase,
can have an improved transfer rate into the diffused liquid phase,
while reaction product gas components, which build up in the
diffused liquid phase, can have an improved transfer rate out of
the diffused liquid phase.
[0091] In certain illustrative embodiments, to maximize diffusion
it is desirable to have high interfacial surface area between the
liquid and gas phases at the interface of exchange layers 140 and
element beds 120 in the vessels 100 in order to create sufficient
exchange between the phases. The combined action of collector media
20 and releaser media 30 contained in an exchange layer 140 serves
to provide high interfacial surface area between the liquid and
gas. That high surface area provides immediate improvement of gas
exchange with the diffused liquid phase within the exchange layer
140, but also permeates into the local area downstream of the
exchange layer 140 providing continued ability of gas exchange with
the diffused liquid phase contacted with the element bed 120. The
use of exchange layers 140 can be repeated further downstream at
any depth where the interfacial surface area has degraded or the
dissolved gas consumption outpaces the diffusion rate of the gas
phase into the liquid phase to provide regeneration of high surface
area interface and exchange capability. This could lead to varying
layer depths of exchange layers 140 or varying depths of element
beds 120 between exchange layers 140 depending on the processing
needs and conditions.
[0092] In certain illustrative embodiments, the one or more
exchange layers 140 can be composed of both collector media 20 and
releaser media 30. The collector media 20 and releaser media 30 can
be in alternating layers, as shown in FIG. 13, as stratified
structures, or combinations thereof. In certain illustrative
embodiments, the collector media 20 and releaser media 30 would
fill the cross-section of the processing vessel 100 and have depths
of 3'' to 12''.
[0093] In certain illustrative embodiments, the development of thin
film 35 can be within the collector media 20 themselves. This would
allow gas exchange to occur in both the collector media 20 and any
surrounding releaser media 30, increasing the amount of time
desirable feed steam gases would have to diffuse into the liquid
and undesirable product gases would have to diffuse out of the
reaction zone. The pore diameter for such collector media 20 would
be between 100 microns and 30 millimeters. In this embodiment, the
pore diameter of the collector media 20 can be larger than the pore
diameter of the surrounding releaser media 30.
[0094] In certain illustrative embodiments, as shown in FIG. 12,
exchange layers 140 can be positioned relative to the top-bed 170
of the vessel 100 and the feed entry points. Vessel 100 can also
include engineered mixer equipment 190 such as a mixer or
distribution tray which can perform as designed or can
under-perform in the event of faulty operation. Exchange layer 140
can be positioned immediately downstream of such engineered mixer
equipment 190 and immediately upstream of the most upstream element
bed 120. Exchange layers 140 can also be positioned relative to
intermediate feed points 180 on vessel 100, which can be quench
ports or distribution trays, typically used to supplement feed of
gas phases. Exchange layer 140 positioning can be such that void
spaces are provided between such equipment or bed layers.
[0095] In prior art vessels, gas exchange ability can degrade in
conventional trickle bed flow regimes and initial flow can be
degraded as well, as illustrated in the "prior art" vessel in FIG.
11. In certain illustrative embodiments, this degradation can be
mitigated via a process of collection and release to be repeated
within a single exchange layer 140 within vessel 100, or by
periodically repeating or strategically placing a plurality of
exchange layers 140 throughout the bed or vessel 100 or to have an
entire bed or vessel 100 comprised of exchange layers 140, as
illustrated in the vessel 100 on the right in FIG. 11, whereby gas
exchange capability is improved.
[0096] In certain illustrative embodiments, exchange layers 140 can
be positioned relative to the position of elements 125 within the
vessel 100. Elements 125 can be positioned downstream of the
exchange layer 140. The depth of elements 125 can be from 6 inches
to 90 feet depending on: the characteristics and properties of the
exchange layers 140; the nature of the fluid phases; the
performance of the thin film 35 in producing trickle bed flows; and
the absence of coking in element bed 120.
[0097] In certain illustrative embodiments, disclosed exchange
layers 140 allow elements 125 to facilitate increased performance
of vessel 100 operations by promoting gas component mixing and
diffusion. Improved rates of gas component exchange mean less
coking and more gas components available for reaction.
Additionally, due to the reactant-rich liquid phase, dispensed by
the releaser media 30, the expected reaction rate between the
diffused gas and undesired species contained at active sites 40 are
increased, thus making better use of the element beds 120 in the
vessel 100.
[0098] Exchange layers 140 could also be advantageously utilized in
applications where vessels are constrained by low gas stream
availability or low gas stream operating pressures or where
hydrogen economics greatly favor conserved operations. Lower
operating pressures result in lower exchange of gas components. As
Ficks' laws demonstrate, lower concentrations will reduce the rate
of gas diffusion into the liquid phase. Exchange layers 140 can
improve the rate of diffusion into the liquid phase and can help
conserve hydrogen circulation requirements. Higher availability of
gas phase components to the diffused liquid phase allows for lower
vessel 100 operating temperatures or a slowing vessel 100
temperature increase, increasing the amount of feed the active
sites 40 and the vessel 100 can process, and extending the amount
of time the elements 125 can be on-oil. Additionally, the
processing vessel 100 can have more feed flexibility and can be
able to handle a wider variety of undesired species. An advantage
of such a system is the ability to arrange locations of exchange
layers 140 dependent on the gas component consumption occurring on
the element beds 120. For example, in a hydro-cracking unit which
is consuming 2000 SCF/BBL within a total depth of 60 feet (33
SCF/BBL/FT), may require more frequent or large depth exchange
layers 140 compared to a Naphtha hydro-treater which is consuming
100 SCF/BBL within a total depth of 30 feet (3.3 SCF/BBL/FT). In
the hydrocracker example, exchange layers 140 can be used in
conjunction with a gas quench to enable both cooling of the liquid
stream and mixing of the gas and liquid simultaneously.
[0099] In certain illustrative embodiments, the collector media 20
can be a single collector pane, as shown in FIG. 9 and FIG. 10,
which fills the cross-section of the vessel 100. Additionally, this
collector pane can have a plurality of perforation holes 25 formed
in its cross-section in order to avoid a build-up of gas pressure
on the upstream side of the collector pane. The perforation holes
25 can be filled with releaser media 30, in certain illustrative
embodiments. In certain illustrative embodiments, the collector
pane can be made up of a plurality of interlocking or snug-fitting
parts in order to enable installation and disassembly during the
loading and unloading of the vessel 100. The collector pane can be,
in certain illustrative embodiments, 3'' to 12'' in depth. The
collector pane perforation holes 25 can be, in certain illustrative
embodiments 1/8'' to 3 feet in diameter. The concentration of
perforation holes 25 can be from a single hole 25 across the
cross-section of the vessel 100 up to one hole 25 per square inch.
In certain illustrative embodiments, collector panes could be
stacked on top of each other or used in a stratified collector
media 20/releaser media 30 orientation as previously described
herein
[0100] As used herein, the phrase "at least one of" A, B and C
shall mean only A, or only B, or only C, or any combination of A, B
and C.
[0101] While the disclosed subject matter has been described in
detail in connection with a number of embodiments, it is not
limited to such disclosed embodiments. Rather, the disclosed
subject matter can be modified to incorporate any number of
variations, alterations, substitutions or equivalent arrangements
not heretofore described, but which are commensurate with the scope
of the disclosed subject matter.
[0102] Additionally, while various embodiments of the disclosed
subject matter have been described, it is to be understood that
aspects of the disclosed subject matter may include only some of
the described embodiments. Accordingly, the disclosed subject
matter is not to be seen as limited by the foregoing description,
but is only limited by the scope of the claims.
* * * * *