Note: Descriptions are shown in the official language in which they were submitted.
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I
DEVICE AND METHOD FOR UPGRADING PETROLEUM
FEEDSTOCKS USING AN ALKALI METAL CONDUCTIVE
MEMBRANE
[0001] This application is a divisional of Canadian patent application Serial
No.
2,855,966, filed November 16, 2012.
TECHNICAL FIELD
[0002] The present disclosure relates to a process for removing nitrogen,
sulfur,
heavy metals, and acid protons from sulfur-, nitrogen-, and metal-bearing
shale oil,
bitumen, heavy oil and petroleum refinery streams so that these materials may
be
used as a hydrocarbon fuel. More specifically, the present disclosure relates
to
removing nitrogen, sulfur, heavy metals and acid protons from shale oil,
bitumen,
heavy oil, or petroleum refinery streams while at the same time, upgrading
these
materials to have a higher hydrogen-to-carbon ratio.
BACKGROUND
[0003] U.S. Patent Application Serial No. 12/916,984 has been published as
United
States Patent Application Publication No. 2011/0100874. The reader is presumed
to
be familiar with the disclosure of this published application. This published
application
will be referred to herein as the "874 application."
[0004] The demand for energy (and the hydrocarbons from which that energy is
derived) is continually rising. However, hydrocarbon raw materials used to
provide
this energy often contain difficult-to-remove sulfur and metals. For example,
sulfur
can cause air pollution and can poison catalysts designed to remove
hydrocarbons
and nitrogen oxide from motor vehicle exhaust, necessitating the need for
expensive
processes used to remove the sulfur from the hydrocarbon raw materials before
it is
allowed to be used as a fuel. Further, metals (such as heavy metals) are often
found
in the hydrocarbon raw materials. These heavy metals can poison catalysts that
are
typically utilized to remove the sulfur from hydrocarbons. To remove these
metals,
further processing of the hydrocarbons is required, thereby further increasing
expenses.
CA 2997472 2018-03-05
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[0005] Currently, there is an on-going search for new energy sources in order
to
reduce the United States' dependence on foreign oil. It has been hypothesized
that
extensive reserves of shale oil, which constitutes oil retorted from oil shale
minerals,
will play an increasingly significant role in meeting this country's future
energy needs.
In the U.S., over 1 trillion barrels of usable, reserve shale oil are found in
a relatively
small area known as the Green River Formation located in Colorado, Utah, and
Wyoming. As the price of crude oil rises, these shale oil resources become
more
attractive as an alternative energy source. In order to utilize this resource,
specific
technical issues must be solved in order to allow such shale oil reserves to
be used,
in a cost effective manner, as hydrocarbon fuel. One issue associated with
these
materials is that they contain a relatively high level of nitrogen, sulfur and
metals,
which must be removed in order to allow this shale oil to function properly as
a
hydrocarbon fuel.
[0006] Other examples of potential hydrocarbon fuels that likewise require a
removal
of sulfur, nitrogen, or heavy metals are bitumen (which exists in ample
quantities in
Alberta, Canada) and heavy oils (such as are found in Venezuela).
[0007] The high level of nitrogen, sulfur, and heavy metals in shale oil,
bitumen and
heavy oil (which may collectively or individually be referred to as "oil
feedstock")
makes processing these materials difficult. Typically, these oil feedstock
materials are
refined to remove the sulfur, nitrogen and heavy metals through a process
known as
"hydro-treating."
[0008] Hydro-treating may be performed by treating the material with hydrogen
gas at
an elevated temperature and an elevated pressure using catalysts such as CO-
M0/A1203 or Ni-Mo/A1203.
[0009] In the present invention, the oil feedstock is mixed with an alkali
metal (such
as sodium) and hydrogen gas. This mixture is reacted under modest pressure
(and
usually at an elevated temperature). The sulfur and nitrogen atoms are
chemically
bonded to carbon atoms in the oil feedstocks. The sulfur and nitrogen
heteroatoms
are reduced by the alkali metals to form ionic salts (such as Na2S, Na3N,
Li2S, etc.).
To prevent coking (e.g., a formation of a coal-like product), the reaction
occurs in the
presence of hydrogen gas that can form bonds with the carbon atoms of the oil
feedstock previously bonded to the heteroatoms. The hydrogen atom bonds to the
carbon atoms that were previously bonded to the heteroatoms, thereby
increasing the
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hydrogen-to-carbon ratio of the oil feedstock and decreasing the heteroatom to
carbon ratio of the resulting organic feedstock. After the hydro-treating
reaction, the
organic phase (oil feedstock) is less viscous and may be sent for further
refining into
a hydrocarbon fuel material.
[0010] The ionic salts formed in the hydro-treating process may be removed
from the
organic products by filtering, or first mixing the treated feedstock with
hydrogen
sulfide to form an alkali hydrosulfide, which forms a separate phase from the
organic
phase (oil feedstock). This reaction is shown below with sodium (Na) being the
alkali
metal, although other alkali metals may also be used:
Na2S + H2S ¨+ 2NaHS (which is a liquid at 375 C)
Na3N + 3H2S 3NaHS + NH3
The nitrogen product is removed in the form of ammonia gas (NH3) which may be
vented and recovered, whereas the sulfur product is removed in the form of an
alkali
hydro sulfide, NaHS, which is separated for further processing. Any heavy
metals will
also be separated out from the organic hydrocarbons by gravimetric separation
techniques.
[0011] As part of the process, alkali metals are used. An advantage of using
alkali
metals such as sodium or lithium instead of hydrogen to reduce the heteroatoms
is
alkali metals offer a greater reduction strength. In other words, the alkali
metals are
better able to reduce the heteroatoms and form alkali metal nitrides or alkali
metal
sulfides. Further, by using alkali metals, there is less need to saturate
rings with
hydrogen to destabilize them so that the heteroatoms can be reduced, making it
possible to remove heteroatoms with significantly less hydrogen.
[0012] It should be noted that the alkali metal treatment process is known in
the
industry and is described, for example, in U.S. Patent No. 3,787,315, U.S.
Patent
Application Publication No. 2009/0134040 and U.S. Patent Application
Publication
No. 2005/0161340.
[0013] A disadvantage of using the hydro-treating process is that hydrogen gas
is a
necessary reactant needed for the hydro-treating process. However, hydrogen
gas
can be expensive. Typically, hydrogen gas is formed by reacting hydrocarbon
molecules with water. For example, in the United States, 95% of the hydrogen
is
CA 2997472 2018-03-05
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formed using the Steam-Methane Reforming Process from natural gas. In the
first
step known as the reforming step, methane (CF-f4) in natural gas is reacted
with steam
(H20) at 750 C - 800 C to produce synthesis gas (syngas). Syngas is a
mixture
primarily comprised of hydrogen gas (H2) and carbon monoxide (CO). In the next
step, known as the water gas shift reaction, the carbon monoxide produced in
the first
reaction is reacted with steam (H20) over a catalyst to form hydrogen gas (H2)
and
carbon dioxide (CO2). This second process (e.g., the water gas shift reaction)
occurs
in two stages: the first stage occurring around 350 C and the second stage
occurring
at about 200 C.
[0014] The overall reaction for the Steam-Methane Reforming Process is as
follows:
CH + 2H20¨> 4H2 + CO2
Thus for every (theoretical) mole of hydrogen gas produced, 0.25 moles methane
and
0.5 moles of water are required. Also, for every mole of hydrogen gas
produced, 0.25
moles of carbon dioxide are produced and released to the atmosphere. It should
be
noted that the Steam-Methane Reforming Process is typically only 65-75%
efficient.
Thus at 70% efficiency, the Steam-Methane Reforming Process will actually
utilizes
0.36 moles of methane and 0.71 moles of water while releasing 0.36 moles of
carbon
dioxide for every mole of hydrogen produced.
[0015] This production of carbon dioxide during the hydro-treating process is
considered problematic by many environmentalists due to rising concern over
carbon
dioxide emissions and the impact such emissions may have on the environment.
[0016] An additional problem in many regions is the scarcity of water
resources. For
example, in the region of Western Colorado and Eastern Utah where parts of the
Green River Formation of shale oil is located, the climate is arid and the use
of water
in forming hydrogen gas can be expensive.
[0017] Alternatively, some industrialists have used an electrolysis process to
provide
the hydrogen gas supply needed for their hydro-treating process. This
electrolysis
reaction involves the electrolytic decomposition of water. In this
electrolytic reaction,
water is split to form hydrogen at a cathode and oxygen at an anode: H20-> H2
% 02
In this reaction, electrical energy is used to split the water. If the cell
runs at 90%
efficiency and runs at about 1 .4 Volts, then the electrical energy required
is about 72
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kcal per mole of created hydrogen. For every mole of hydrogen produced in this
electrolysis reaction, one mole of water is consumed. Because one mole of
water is
consumed to produce hydrogen in this method, more water is required to produce
the
hydrogen gas via electrolysis than is required to produce the hydrogen using
the
Steam-Methane Reforming Process (which requires 0.71 moles water). Thus, in
arid
climates where the cost of water is high, using an electrolysis process to
produce
hydrogen may not be economically feasible.
[0018] While conventional hydro-treating processes are known, they are
expensive
and require large capital investments in order to obtain a functioning hydro-
treating
plant. There is a need in the industry for a new process that may be used to
remove
heteroatoms such as sulfur and nitrogen from oil feedstocks, but that is less
expensive than hydro-treating. Such a process is disclosed herein.
[0019] Additionally, naphthenic acids must be removed from many organic
streams
that are produced by refineries. Naphthenic acids ("NAPs") are carboxylic
acids
present in petroleum crude or various refinery streams. These acids are
responsible
for corrosion in refineries. A common measure of acidity of petroleum is
called the
Total Acid Number ("TAN") value and is defined as the milligrams (mg) of
potassium
hydroxide needed to neutralize the acid in one gram of the petroleum material.
(Other
acids found in the oil feedstock may also contribute to the TAN value). All
petroleum
streams with TAN >1 are called high TAN. NAPs are a mixture of many different
compounds and cannot be separated via distillation. Moreover high TAN crudes
are
discounted over Brent Crude prices. For example, Doba crude with a TAN of 4.7
is
discounted by $19 per barrel on a base price of $80 for Brent crude.
[0020] NAPs boil in the same range as that of kerosene/jet fuel. (However,
kerosene/jet fuels have very stringent TAN specifications.) Attempting to
neutralize
these acids using aqueous caustic or other bases form salts. These salts in
presence
of water, lead to formation of stable emulsions. Additional methodologies of
NAP
reduction include hydrotreating or decarboxylation that are both destructive
methodologies and the NAPs cannot be recovered using these methods. Solvent
extraction or adsorption methodologies lead to high costs and energy usage for
sorbent regeneration or solvent boiling. A new method for NAPs removal with
lower
energy consumption wherein NAPs can be recovered and processed as commercial
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products is required. Accordingly, a new method of neutralizing and/or
removing
NAPs is needed. Such a method and device is disclosed herein.
SUMMARY
[0021] The present embodiments include a method of upgrading an oil feedstock
with
the benefit of a strong alkali metal agent without directly being required to
handle,
store, or transport the alkali metal. The method comprises obtaining a
quantity of an
oil feedstock, the oil feedstock comprising at least one carbon atom and a
heteroatom
and/or one or more heavy metals. The quantity of the oil feedstock is reacted
with an
alkali metal generated on an electrode within the reactor. The reaction with
the alkali
metal may also include using an upgradant hydrocarbon such as hydrogen gas or
a
hydrocarbon.
[0022] In order to implement these embodiments, a reactor may be utilized with
at
least two chambers separated in part by a membrane conductive to alkali metal
ions.
This membrane conducts alkali metal ions from an alkali metal ion source
material
(such as a liquid comprised of sodium salts or sodium metal). A positive
charged
electrode (anode) is in communication with the alkali metal ion source. The
opposite
chamber of the reactor (called the feedstock chamber) includes a feedstock
stream
(comprised of the organic oil feedstock) and a negatively charged electrode
(cathode). The alkali metal enters the feedstock chamber and reacts with the
heteroatom and/or the heavy metals in the feedstock to form one or more
inorganic
products, wherein the upgradant hydrocarbon reacts with the oil feedstock to
produce
an upgraded oil feedstock. The reaction with the upgradent hydrocarbon
operates
such that the number of carbon atoms in the upgraded oil feedstock may be
greater
than the number of carbon atoms in the original oil feedstock. The inorganic
products
are then separated from the upgraded oil feedstock. (The reaction of the oil
feedstock, the alkali metal, and the upgradant hydrocarbon molecule may be
implemented with or without using hydrogen gas. If hydrogen gas is utilized,
the
amount of hydrogen gas needed is much less than would be required using
conventional hydrotreating.)
[0023] In some embodiments, the alkali metal comprises sodium, lithium, or
alloys of
lithium and sodium. The upgradant hydrogen source may comprise hydrogen,
natural
gas, shale gas and/or mixtures thereof. In other embodiments, the upgradant
hydrocarbon comprises methane, ethane, propane, butane, pentane, their
isomers,
CA 2997472 2018-03-05
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ethene, propene, butene, pentene, dienes, and/or mixtures thereof. (Oil retort
gas,
which is a mixture of gases that is produced in a refinery process may also be
used
as the upgradant hydrocarbon.)
[0024] The process of reacting the feedstock with the alkali metal may consist
of two
steps. A first step involves having alkali metal ions be transferred across
the
membrane and reduced to metal at the membrane surface at a negatively charged
electrode (which may be directly fixed to the membrane surface). A second step
involves having the formed alkali metal react directly with the constituents
in the oil
feedstock (or carried away with the oil to react downstream). The electrode
where the
alkali metal is formed may be porous, or comprised of a mesh. In another
embodiment, the electrode may be a film of metallic alkali metal connected to
an
electrical lead (or current collector). To maintain continuity, a screen or
mesh may
provide a divider to separate a zone where the alkali metal is reduced from
the oil
feedstock. This screen allows the alkali metal to pass through as it is
formed.
[0025] The reaction between the alkali metal and the oil feedstock may occur
at a
pressure that is between barometric and about 2500 psi and/or at a temperature
that
is between about 100 C temperature and 450 C. In other embodiments, the
reaction
between the alkali metal and the oil feedstock occurs at a temperature that is
above
the melting point of the alkali metal but is lower than 450 C. Further
embodiments
may utilize a catalyst in the reaction. The catalyst may comprise molybdenum,
nickel,
cobalt or alloys thereof, molybdenum oxide, nickel oxide or cobalt oxides
and/or
combinations thereof.
[0026] As the reaction between the alkali metal and the oil feedstock produces
inorganic products, a separation step may be needed. The separation used in
the
process may occur in a separator, wherein the inorganic products form a phase
that
is separable from an organic phase that comprises the upgraded oil feedstock
and/or
unreacted oil feedstock. To facilitate this separation, a flux may be added to
the
separator. After separation, the alkali metal from the inorganic products may
be
regenerated and reused.
[0027] The upgraded oil feedstock produced in the reaction may have a greater
hydrogen-to-carbon ratio than the oil feedstock. The upgraded oil feedstock
produced
in the reaction may also have a greater energy value than the oil feedstock.
Further,
CA 2997472 2018-03-05
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the heteroatom-to-carbon ratio of the upgraded oil feedstock may be less than
the
heteroatom-to-carbon ratio of the oil feedstock.
[0028] Additional embodiments may be designed in which an alkali metal is
added to
the oil feedstock in order to reduce the TAN value of the oil feedstock.
Specifically,
the alkali metal may react with the oil feedstock to remove the acidic
components,
thereby lowering the TAN value. In some embodiments, the original (unreacted)
oil
feedstock may have a TAN value of greater than or equal to 1 , but after
reaction with
the alkali metal, may have a TAN value of less than or equal to 1 .
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 shows a schematic drawing of a device that may be used to de-
acidify a quantity of an oil feedstock;
[0030] Figure 2 shows a schematic drawing of a device that may be used to
upgrade
a quantity of an oil feedstock;
[0031] Figure 3 shows a schematic drawing of a device that may be used to de-
acidify a quantity of an oil feedstock;
[0032] Figure 4 shows a schematic drawing of another embodiment of a device
that
may be used to de-acidify a quantity of an oil feedstock;
[0033] Figure 5 shows a schematic drawing of another embodiment of a device
that
may be used to upgrade a quantity of an oil feedstock;
[0034] Figure 6 is a flow diagram of a method for upgrading a quantity of an
oil
feedstock; and
[0035] Figure 7 a schematic drawing of another embodiment of a system that may
be
used to upgrade a quantity of an oil feedstock.
DETAILED DESCRIPTION
[0036] The present embodiments relate to a method to de-acidify feedstocks and
refinery streams. Such de-acidification is beneficial as it may operate to
reduce piping
corrosion and may convert naphthenic acids to a salt form. The present
embodiments
involve the addition of alkali metals (such as sodium or lithium metal) to the
CA 2997472 2018-03-05
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feedstocks as a means of reacting with the naphthenic acids, thereby de-
acidifying
these acids. When this reaction occurs, the naphthenic acids may be converted
into
the corresponding sodium or lithium salts (or other inorganic products).
Hydrogen gas
is also formed in this reaction. This reaction is summarized as follows:
[0037] R-COOH + Na--+ (R-000")Na+ + 1/2 H2
[0038] Alternatively, the sodium may further react with oxygen atoms to
eliminate the
carboxyl group as shown in the following formula:
[0039] R-COOH + 4Na + H2¨>R-CH3 + 2Na20
[0040] The reaction with NAPs in this manner may be desirable and may result
in a
reduction of Total Acid Number ("TAN") associated with the oil feedstock.
There are
multiple different ways in which the alkali metal may be added to the
feedstock. In
one embodiment, the sodium or lithium metal is directly added to the stream.
Once
this occurs, the inorganic products may then be filtered from the oil stream.
Other
embodiments may also be designed (as described herein) to provide other
mechanisms for adding the alkali metal to the stream of oil feedstock (such
as, for
example, by forming the alkali metal in situ).
[0041] It should be noted that, in addition to reacting with the acids (such
as
naphthenic acids), the alkali metals that are added to the feedstock may also
react to
remove sulfur, nitrogen, metals (such as heavy metals), etc. This process for
removing these metals/heteroatoms is discussed in the '874 application. Thus,
by
adding alkali metals to the oil feedstock, the problems associated with
metals/heteroatoms in the stream, as well as problems with acids in the
stream, may
be overcome.
[0042] It should be noted that many in the oil processing industry are
uncomfortable
handling metallic sodium or lithium because of its reactive nature. In other
words,
these practitioners are uncomfortable using sodium/lithium and are
uncomfortable
adding these reagents directly to their oil feedstock streams. Accordingly,
the present
embodiments also provide methods and devices which operate to
electrochemically
produce alkali metals within an oil feedstock chamber (e.g., in situ), thereby
bringing
an alkali metal such as sodium in direct contact with the feedstock. Once this
alkali
metal is produced in the chamber, it is consumed by reacting with the heavy
CA 2997472 2018-03-05
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metals/heteroatoms and/or the acids in the feedstock. These embodiments may be
desirable in that they provide the strong reducing power and reactivity
associated with
alkali metals without ever having an appreciable amount of the metal present.
In other
words, the present embodiments upgrade an oil feedstock using the alkali metal
(e.g.,
a strong agent) without the practitioner being required to handle, store, or
transport
the alkali metal.
[0043] Referring now to Figure 1 , a device 2 is illustrated that may be used
to de-
acidify a quantity of a first oil feedstock 9. As shown in Figure 1 , the oil
feedstock 9 is
a liquid that is placed within a chamber 3. The chamber 3 may be a reaction
vessel, a
chamber of an electrolysis cell (as will be described herein), etc. Those
skilled in the
art will appreciate what vessels, containers, etc., may be used as the chamber
3.
[0044] The oil feedstock 9 comprises a quantity of naphthenic acids 8. As
described
above, naphthenic acids 8 comprise carboxylic acids present in petroleum crude
or
various refinery streams. Naphthenic acids 8 are a mixture of many different
compounds and cannot be separated out via distillation. In order to eliminate
the
naphthenic acids 8 from the oil feedstock 9, a quantity of an alkali metal 5
is added to
the chamber 3. (The alkali metal is abbreviated as "AM.") In some embodiments,
the
alkali metal may be sodium, lithium or alloys of sodium and lithium. The
chamber 3
may be kept at a temperature that is above the melting point of the alkali
metal 5 such
that the liquid alkali metal 5 may easily be added to the liquid oil
feedstock. In some
embodiments, the reaction occurs at a temperature that is above the melting
point of
the alkali metal (or above a temperature of about 100 C). In other
embodiments, the
temperature of the reaction is less than about 450 C.
[0045] When added to the chamber 3, the alkali metal 5 may react with the oil
feedstock 9. More specifically, the alkali metal 5 reacts with the quantity of
the
naphthenic acids 8 to form a de-acidified feedstock 12. As inorganic acid
products 13
may also be formed from this reaction, a product separator 10 may be used to
separate the de-acidified oil feedstock 1 2 from the inorganic acid products.
Those
skilled in the art will appreciate how this separation may occur. Moreover,
those
skilled in the art will appreciate the structures (such as a settling chamber,
etc.) that
may be used as the product separator 10. The product separator 10 may be
integral
with the chamber 3 or may be a separate structure, as shown in Figure 1 .
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[0046] As explained herein, the reaction between the alkali metal 5 and the
naphthenic acids 8 operates to eliminate the naphthenic acids 8 from the oil
feedstock 9. Thus, the TAN value of the de-acidified oil feedstock 12 will be
lower
than the TAN value of the original (unreacted) first oil feedstock 9. For
example, in
some embodiments, the TAN value of the original (unreacted) oil feedstock 9
may be
greater than or equal to 1 (such as, for example, 3, 4, 5, etc.) whereas the
TAN value
of the de-acidified oil feedstock 12 is a lower value, such as less than or
equal to 1 .
As noted above, other acids in the oil feedstock 9 may contribute to the TAN
value of
the feedstock 9. These acids may also react with the alkali metal in a similar
manner,
further reducing the TAN value.
[0047] This reduction in TAN value may provide a significant financial benefit
to the
owner of the oil feedstock. As noted above, prices per barrel of oil products
that are
considered to be high TAN (e.g., with a TAN value greater than 1 ) are often
discounted significantly with respect to barrels of oil products that are low
TAN. Thus,
by reducing the TAN value in the oil feedstock, the value of the oil feedstock
may be
significantly increased.
[0048] Referring now to Figure 2, another embodiment of the device 2a is
illustrated.
As noted above, the device 2a is similar to the device 2 shown in Figure 1 .
The
device 2a may be designed to de-acidify the oil feedstock 9. At the same time,
the
device 2a may also be designed to further upgrade the first oil feedstock 9 by
removing heavy metals 14 and/or one or more heteroatoms 1 1 that are present
in
the oil feedstock 9.
[0049] As described above, heavy metals 14 (such as nickel, vanadium, iron,
arsenic,
etc.) are often found in samples of oil feedstock materials 9. In some
embodiments, it
may be desirable to remove these heavy metals 14, as such metals can poison
catalysts that are typically utilized in hydrocarbon processing. However, as
shown in
Figure 2, the device 2a may be designed such that the alkali metal 5 may react
with
the heavy metals 14 in the oil feedstock 9. More specifically, in addition to
the alkali
metal 5 reacting with the napthenic acids 8 to de-acidify the feedstock (as
described
above), the quantity of the alkali metal 5 may further react with the heavy
metals 14,
thereby reducing the heavy metals into their metallic states. This reaction
may also
occur in the chamber 3.
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[0050] As shown in Figure 2, these heavy metals 1 6 may then be separated and
recovered (using the product separator 10). It should be noted that the heavy
metals
16, in their metallic state, are inorganic materials and thus may separate out
from the
organic oil feedstock materials. Accordingly, the product separator 10 may use
this
property as a means of separating out the heavy metals 16. Those skilled in
the art
will appreciate that other separation techniques may also be used to separate
out the
heavy metals 16. Once the metals 16 have been separated, they may be
recovered,
sold, used in further processing, etc. As these metals are generally expensive
commodities, the fact that such metals may be collected (and used/sold) may
provide
a significant commercial advantage for the owner of the feedstock.
[0051] In addition to removing heavy metals, the alkali metal 5 may also react
with
one or more heteroatoms 1 1 (such as N, S) that are present in the oil
feedstock 9.
These N, S atoms may be bonded to the carbon/hydrogen atoms in the organic oil
feedstock 9. However, as noted herein, the alkali metal 5 may react with these
one or
more heteroatoms 1 1 to form inorganic sulfur/nitrogen products 17. For
example, if
the alkali metal 5 is sodium, then the reaction with the heteroatoms 1 1 forms
inorganic sulfur/nitrogen products 17 such as Na2S, Na3N and/or other
inorganic
products. (Again, a product separator 1 0 may be used to separate out the
inorganic
sulfur/nitrogen products 17 from the oil feedstock). Once the inorganic
sulfur/nitrogen
products 17 have been removed, the heteroatom to carbon ratio of the resulting
oil
feedstock is less than the heteroatom to carbon ratio of the original
(unreacted) oil
feedstock 9.
.
[0052] It should be noted that after the oil feedstock 9 has been de-
acidified,
demetalized, de-sulfurized and/or de-nitrogenized, then this oil feedstock is
referred
to as an "upgraded" oil feedstock 12a in that this material is better suited
for further
refining, commercialization, etc.
[0053] It should be noted that in the embodiment shown in Figure 2, a single
product
separator 10 is shown as separating out the heavy metals 16, the inorganic
acid
products 13 and the inorganic sulfur/nitrogen products 17, thereby removing
these
materials from the upgraded oil feedstock 12a. However, those skilled in the
art will
appreciate that multiple product separators 10 and/or separation techniques
may be
used to accomplish such separations. Further, there also may be a sequential
separation of the various materials from the upgraded oil feedstock 1 2a.
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[0054] Likewise, it should be noted that in the embodiment of Figure 2, a
single
chamber 3 is used to react the oil feedstock 9 with the alkali metal 5 (and
thus
remove the naphthenic acids 8, heavy metals 14 and heteroatoms 1 1 from the
organic feedstock). Those skilled in the art will appreciate that such
reactions could
also occur in different chambers. In other words, embodiments may be designed
in
which a first chamber is used to react the alkali metal 5 with the heavy
metals 14 (and
the heavy metals 14 are subsequently separated out), a second chamber is used
to
react the alkali metal 5 with the naphthenic acid 8 (and the acid products 1 3
are
subsequently separated out) and then a third chamber used to react the alkali
metal 5
with the heteroatoms 1 1 (and the sulfur/nitrogen products 17 are subsequently
separated out). Of course, if different chambers were used for each of these
reactions, the reaction conditions such as pressure, temperature, flow rates,
etc.,
could be adjusted/tailored to optimize each specific reaction.
[0055] In the embodiments shown in Figures 1 and 2, the alkali metal 5 is
shown
being added to the chamber 3. Those skilled in the art will appreciate that
there are a
variety of different ways by which the alkali metal 5 may be added in order to
induce a
reaction. For example, a sample of the alkali metal 5 may simply be added to
the
chamber 3. However, many in the oil processing industry are uncomfortable
handling
metallic sodium (or other metallic alkali metals) because of their reactive
nature.
Thus, other embodiments may be designed in which the alkali metal 5 is formed
in
situ within the chamber 3 from alkali metals ions. In other words, alkali
metal ions are
added to the chamber 3 (which are safe and easy to handle) and then such ions
are
reduced back to the metallic state via an electrochemical reduction reaction.
Once
these alkali metal ions have been reduced in situ to form the metallic alkali
metal 5,
these formed alkali metals 5 immediately react with the oil feedstock 9 (in
the manner
outlined herein) and are thus consumed almost instantaneously after formation.
The
embodiments that electrochemically form the alkali metal in situ can be
advantageous
in that they provide the strong reducing power and reactivity of alkali metal
to the oil
feedstock without ever having an appreciable amount of the metal present.
[0056] Referring now to Figure 3, an embodiment of a device 1 00 that may be
used
to de-acidify oil feedstocks, as well as remove the heteroatoms/heavy metals
and/or
upgrade the feedstock is illustrated. Specifically, the device 100 consists of
at least
two chambers, namely a feedstock chamber 20 and an alkali metal source chamber
CA 2997472 2018-03-05
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30. The feedstock chamber 20 has an outer wall 21 and may have an inlet 22 and
outlet 23.
[0057] The feedstock chamber 20 may be separated from the alkali metal source
chamber 30 by an alkali metal ion conductive separator 25. The ion separator
25 may
be comprised of ceramic materials generally known as Nasicon, sodium beta
alumina, sodium beta prime alumina or sodium ion conductive glass if the
alkali metal
is sodium; or Lisicon, lithium beta alumina, lithium beta prime alumina or
lithium ion
conductive glass if the alkali metal is lithium. The materials used to
construct the ion
separator 25 are commercially available from Ceramatec, Inc., of Salt Lake
City,
Utah.
[0058] A cathode 26 which is negatively charged and connected to a power
source 40
(via wires 42) may be, at least partially, housed within the feedstock chamber
20.
Preferably the cathode 26 is located in close proximity to the ion separator
25 to
minimize ionic resistance. The cathode 26 may be contacting the ion separator
25 (as
shown in Figure 3) or screen printed on the ion separator 25. In other
embodiments,
the cathode 26 may be integrated with the ion separator 25 as disclosed in
U.S.
Patent Publication 2010/0297537 entitled "ELECTROCHEMICAL CELL
COMPRISING IONICALLY CONDUCTIVE MEMBRANE AND POROUS
MULTIPHASE ELECTRODE". By placing the cathode 26 on or near the ion
separator 25, the oil feedstock does not necessarily have to be ionically
conducting in
order to transfer ions/charges.
[0059] The alkali metal source chamber 30 has an outer wall 31 and may have an
inlet 32 and outlet 33. An anode 36 (which is positively charged) and
connected to the
power source 40 (via wires 42) may be, at least partially, housed within the
source
chamber 30. Suitable materials for the cathode 26 include materials
comprising,
carbon, graphite, nickel, iron which are electronically conductive. Suitable
materials
for the anode 36 include materials comprising titanium, platinized titanium,
carbon,
graphite. In the embodiment shown in Figure 3, the cathode 26 and the anode 36
are
connected to the same power supply 40. Further, Figure 3 shows the wires 42
exiting
the chambers 20, 30 via inlets 22, 32. Such depictions are made for clarity
and are
not limiting. Those skilled in the art will appreciate how the power source
40/wires 42
may be otherwise arranged in order to connect to the cathode 26 and/or the
anode
CA 2997472 2018-03-05
15
36. Likewise, those skilled in the art will appreciate that the cathode 26 and
the anode
36 may be connected to power supplies in various manners, etc.
[0060] A mode of operation for the device 100 will now be described.
Specifically, a
first oil feedstock 50 may enter the feedstock chamber 20 (such as, for
example, by
flowing through the inlet 22). Concurrently, a dissolved solution of alkali
metals 51 will
flow through the alkali metal source chamber 30. This solution of alkali
metals may
be, for example, a solution of sodium sulfide, lithium sulfide, sodium
chloride, sodium
hydroxide, etc. A voltage is then applied to the anode 36 and cathode 26 from
the
source 40. This voltage causes chemical reactions to occur. These reactions
cause
alkali metal ions 52 (abbreviated "AM ions" 52") to pass through the ion
separator 25.
In other words, the alkali metal ions 52 flow from the alkali metal source
chamber 30,
through the ion separator 25, into the feedstock chamber 20.
[0061] Once the alkali metal ions 52 (such as, for example, sodium ions or
lithium
ions) pass through the ion separator 25, the ions 52 are reduced to the alkali
metal
state 55 (e.g., into sodium metal or lithium metal) at the cathode 26. Once
formed, the
alkali metal 55 intermixes with the feedstock 50 (as shown by arrow 58). As
described
herein, the reaction between the oil feedstock 50 and the alkali metal 55 may
involve
a reaction between the acids (such as naphthenic acid) in the oil feedstock
50. Thus,
the reaction with the alkali metal 55, which was formed in situ within the
chamber 20,
operates to reduce the acid content in the oil feedstock 50, thereby reducing
the TAN
value of the oil feedstock 50.
[0062] Additionally and/or alternatively, the reaction between the oil
feedstock 50 and
the alkali metal 55 formed within the chamber 20 may cause a reaction with the
sulfur
or nitrogen moieties within the oil feedstock 50. This reaction may also
reduce heavy
metals, such as vanadium and nickel in the feedstock 50. Further, as explained
in the
'874 application, at an elevated temperature and elevated pressure, the
reaction
between alkali metals 55 and the heteroatoms (S, N) forces the sulfur and
nitrogen
heteroatoms to be reduced by the alkali metals into ionic salts (such as Na2S,
Na3N,
Li2S, etc.). These ionic salts may then be removed from the oil feedstock 50.
As such,
the content of sulfur and nitrogen within the oil feedstock 50 may be
significantly
reduced by the reaction of the alkali metal 55 formed within the chamber 20.
In other
words, the heteroatom-to-carbon ratio of the upgraded oil feedstock may be
less than
the heteroatom-to-carbon ratio of the original (unreacted) oil feedstock.
Also, the
CA 2997472 2018-03-05
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amount of heavy metals in the feedstock may further be reduced. Thus, the
ratio of
carbon to heavy metals in the upgraded (reacted) feedstock is less than the
ratio of
carbon to heavy metals in the original (unreacted) feedstock.
[0063] Further, in addition to the oil feedstock 50, the chamber 20 may also
include a
quantity of an upgradant hydrocarbon 60 that reacts with the oil feedstock 50
(as
shown by arrow 74). Specifically, as taught by the '874 application, when the
sulfur/nitrogen moieties of the oil feedstock 50 react with the alkali metals
55, radical
species are formed that may react with the upgradant hydrocarbon 60. In some
embodiments, the upgradant hydrocarbon 60 may be hydrogen gas, including the
hydrogen gas formed by the reaction with naphthenic acid. (It should be noted
that if
hydrogen is used as the hydrocarbon 60, the amount of hydrogen needed is less
than
the amount of hydrogen that would be required if a typical hydrotreatment
process
were utilized). In other embodiments, the upgradant hydrocarbon 60 comprises
natural gas, shale gas and/or mixtures thereof, methane, ethane, propane,
butane,
pentane, their isomers, ethene, propene, butene, pentene, dienes, and/or
mixtures
thereof. As explained in the '874 application, this reaction with the
upgradant
hydrocarbon 60 may operate to produce an upgraded hydrocarbon that has a
greater
hydrogen-to-carbon ratio than the original oil feedstock 60. The upgraded oil
feedstock produced in the reaction may also have a greater energy value than
the
original oil feedstock 60. Typically the presence of upgradant hydrocarbon 60
may
result in a reduction of formation of insoluble solids during the reaction. It
is believed
that these solids are large organic polymers that are formed as part of the
radical
reactions. However, by using the upgradant hydrocarbon 60, this hydrocarbon 60
acts as a "capping" species that prevents the formation of these solid,
organic
polymers. Thus, by using the hydrocarbon 60, the subsequent yield of the
liquid oil
feedstock (e.g., the desired product) may be increased.
[0064] The reactions described in Figure 3 may be conducted at elevated
temperatures. For example, the reactions may occur at temperatures above the
melting temperature of sodium or at higher temperatures found effective for
the
particular feedstock. The mode of operation of the device 1 00 may further
consist of
using molten sodium as the sodium source 51 in the alkali metal source chamber
30
or lithium metal as the lithium source. The reactions may further be conducted
at
elevated pressure, for example in the 300 - 2000 pounds per square inch range.
CA 2997472 2018-03-05
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[0065] In some embodiments, the oil feedstock 50 may be passed through the
device
100 (as the solution of sodium sulfide also passed through). Once passed
through the
device 1 00, the oil feedstock may flow into another vessel operated at a
different
temperature and pressure (e.g., temperatures and pressures more conducive to
the
reactions desired and where the residence time of the feedstock in the second
vessel
size is matched to the reaction kinetics and flow rates).
[0066] As described herein, various solids, inorganic compounds, etc., may be
formed when performing the reactions outlined herein. These inorganic products
may
comprise Na2S, NaN3, heavy metals and solid organic polymers that are formed
by
the radical reactions. In order to deal with these inorganic compounds, the
process
used in conjunction with the device of Figure 3 may further involve filtering,
or
separating by centrifugal forces the feedstock after it has been exposed to
the sodium
for sufficient time to remove solids from the liquids. This separation may
involve the
use of a separator 80, as described below.
[0067] The oil feedstock 50, alkali metal solution 51 and other components of
the
device 100 may be dissolved in a polar solvent such as Formamide, Methyl
formamide, Dimethyl formamide, Acetamide, Methyl acetamide, Dimethyl
acetamide,
Triethylamine, Diethyl acetamide, Ethylene glycol, Diethylene glycol,
Triethylene
glycol, Tetraethylene glycol, Ethylene Carbonate, Propylene Carbonate,
Dimethylpropyleneurea, Butylene Carbonate, Cyclohexanol, 1 ,3-Cyclohexanediol,
1
,2 Ethanediol, 1 ,2-Propanediol, Ethanolamine, Methyl sulfoxide, Dimethyl
sulfoxide,
Tetramethylene sulfoxide, Sulfolane, Gamma-butyrolactone, Nitrobenzene,
Acetonitrile, Pyridine, quinoline, ammonia, ionic liquids or molten fused
salts. For
example, the alkali metal solution 51 may be dissolved in one or more of these
solvents and then be allowed to flow into the alkali metal source chamber 30.
(The
salts that are used for the alkali metal solution 51 may be alkali metal
chlorides,
hydroxides, phosphates, carbonates, sulfides and the like.) Similarly, such
solvents
may be used with the oil feedstock 50 and/or the hydrocarbon 60 and then the
mixture may be allowed to flow into the chamber 20.
[0068] Depending on the alkali metal source (e.g., the alkali metal solution
51), the
anode reaction in the alkali metal source chamber 30 may vary. For example
sulfides
may form polysulfides and or elemental sulfur, chlorides may form chlorine
gas,
hydroxides may form oxygen gas, carbonates may form oxygen gas and evolve
CA 2997472 2018-03-05
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carbon dioxide and the like. If the alkali metal source is an alkali metal,
metal ions will
simply form. These variations constitute different embodiments. Gas handling
and
recovery may be a part of the overall process.
[0069] As shown in Figure 3, the products formed in the oil feedstock chamber
20
may be sent to a product separator 80 (as shown by arrow 82). In this product
separator 80, the inorganic products may form a phase that is separable from
an
organic phase that comprises the upgraded oil feedstock and/or unreacted oil
feedstock. To facilitate this separation, a flux may be added to the product
separator.
(Those skilled in the art are familiar with the materials that may be used as
the flux
that will facilitate separation between the organic feedstock materials and
the
inorganic products.) After separation, the alkali metal from the inorganic
products may
be regenerated and reused. In some embodiments, the product separator 80 may
be
a settling chamber or other similar structure.
[0070] Figure 4 is a schematic that includes another embodiment of the device
100.
Much of the structures/elements depicted in Figure 4 are similar to that which
was
described in Figure 3. Accordingly, for purposes of brevity, the discussion of
many of
these structures/elements is omitted.
[0071] Figure 4 depicts a schematic embodiment similar to the depiction in
Figure 3
except a porous partition 101 resides between the ion separator 25 and the
feedstock
50. This partition 101 may be a metal mesh or perforated metal sheet, or glass
fiber
mesh, carbon fiber mesh or other material with holes or pores that will allow
alkali
metal to flow through. Alkali metal 102 is formed at the ion separator 25 and
may
serve as the cathode with a negatively charged current collector 103 in
contact with
the alkali metal 1 02. (Alternatively, the porous partition 101 , if
electronically
conductive, may be negatively charged and serve as the current collector.)
Once the
alkali metal 102 is formed, it may flow through the porous partition 101 and
may then
react with the oil feedstock 50 in the manner described above.
[0072] Thus, as indicated herein, there are at least three different processes
as part
of this invention for de-acidifying these streams:
1) Add sodium or lithium directly to the stream to form the acid salt and
hydrogen,
then filter out the acid salts from the stream;
CA 2997472 2018-03-05
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2) Use the novel device in a mode where a sodium or lithium source in alkali
metal
source chamber and the feedstock is in the feedstock chamber, and where sodium
metal forms at the cathode located with the feedstock chamber, where the
alkali
metal reacts with the feedstock to convert the acids to the sodium or lithium
salt of the
acid and hydrogen evolves as a byproduct;
3) Use the novel device in a mode where a sodium or lithium source in alkali
metal
source chamber and the feedstock is in the feedstock chamber, and where alkali
ions
transport across the ion separator dividing the two chambers under a potential
gradient, and hydrogen evolves at the cathode located with the feedstock
chamber,
where the alkali metal ions combine with the organic acid anions to form a
salt, in this
case using a cathode material with low hydrogen overpotential (such as
platinum or
other materials) may be preferred.
[0073] In the case of acid removal, there may not be any reason to add an
upgradant
hydrocarbon (gas) 60 to the feedstock chamber with the cathode since hydrogen
gas
may be a byproduct. As such, this formed hydrogen may act as the upgradant
hydrocarbon 60. If heteroatoms such as sulfur, or nitrogen are present, an
upgradent
gas 60 such as hydrogen, natural gas, shale gas and/or mixtures thereof, may
be
needed.
[0074] It should also be noted that the addition of the alkali metal 102 may
not simply
neutralize the acidic hydrogen in the napthenic acid. Specifically, naphthenic
acid has
the structure: R¨ COOH. In some embodiments, the alkali metal 102 may react
with
the oxygen atoms (in addition to the hydrogen atoms) such that the remaining
hydrocarbon after the alkali metal addition has the structure R¨ CH3, R¨ H,
etc.
(The reason for this is that the alkali metal 102 may also reduce the oxygen
moiety as
well as the hydrogen moiety.) The formed inorganic products may thus include
NaOH,
Na20, etc. As noted above, after reaction with the alkali metal 103, the TAN
value of
the feedstock 50 is reduced. However, given the above-recited reactions with
the
oxygen moieties, the TAN value may not be increased (or returned to its
original
state) by simply reacting the de-acidified oil feedstock with base (such as
NaOH).
Rather, as described herein, the reduction of the TAN value may also operate
to
convert the napthenic or other acid groups into pure hydrocarbon functional
groups
(such as is R¨ CH3, R¨ H, etc.).
CA 2997472 2018-03-05
20
[0075] Referring now to Figure 5, another embodiment of a device 100 is
illustrated.
Specifically, the device 1 00 may be used to upgrade an oil feedstock 50. More
specifically, the feedstock 50 may be upgraded by having the feedstock 50 be
de-
acidified, desulfirized, demetalized and denitrogenized. In other words, the
device
100 is operable to remove sulfur, heavy metals, acids (such as napthenic acid)
and
nitrogen from the oil feedstock 50.
[0076] The embodiment of the device 100 that is shown in Figure 5 is similar
to that
which is shown and described in Figure 3. For purposes of brevity, much of
this
discussion will be omitted. However, for clarity, the wires 42 and the power
source 40
are not shown in Figure 5. However, those skilled in the art will appreciate
that such
structures are indeed present and may be necessary in order to conduct the
electrolytic reactions associated with the device 1 00.
[0077] As described herein, the oil feedstock 50 shown in Figure 5 may include
quantities of heavy metals, napthenic acid and at least one heteroatom (e.g.,
nitrogen
and sulfur). Accordingly, such materials may be removed from the oil feedstock
50
using the methods outlined herein. Specifically, the oil feedstock 50 is
contacted with
quantities of alkali metals 55a, 55b, 55c. (The arrows 58 are designed to
represent
the reactions between the alkali metals 55a, 55b, 55c and the oil feedstock
50.) More
specifically, the feedstock 50 may be contacted with a first quantity of an
alkali metal
55a. The reaction between the first quantity of the alkali metal 55a and the
feedstock
50 is such that the alkali metal 55a reacts with the heavy metals that are in
the
feedstock 50. This reacted feedstock may then exit the chamber 20 and may pass
through a product separator 80. The purpose of the product separator 80 is to
remove
the heavy metals from the oil feedstock. These heavy metals may then be
recovered,
sold, etc.
[0078] As shown by Figure 5, after passing through the product separator 80,
the
feedstock 50 (minus the heavy metals which were previously removed) may be
brought back into the chamber 20. This chamber 20 may be the same chamber that
was previously used to remove the heavy metals, or it may be a chamber 20 of a
different device 100 that is positioned downstream from the product separator
80.
[0079] Once in the chamber 20, the oil feedstock 50 (which has had the heavy
metals
removed) may then be reacted with a second quantity of the alkali metal 55b.
This
time, the alkali metal 55b reacts with the napthenic acid to form a de-
acidified oil
CA 2997472 2018-03-05
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feedstock, wherein a TAN value of the unreacted oil feedstock is greater than
a TAN
value of the de-acidified oil feedstock. Again, after the acids have been
reacted, the
reacted oil feedstock 50 may be sent to the product separator 80 which may
operate
to remove the inorganic materials that were formed during the reaction with
the
second quantity of alkali metals 55b. This separation of inorganic materials
may occur
within the same product separator 80 that was used to remove the heavy metals
or
may be conducted in a different separator product 80.
[0080] After passing through the product separator 80, the feedstock 50 (minus
the
heavy metals and the napthenic acids which were previously removed) may be
brought back into the chamber 20. This chamber 20 may be the same chamber that
was previously used to remove the heavy metals/napthenic acids, or it may be a
chamber 20 of a different device 100 that is positioned downstream from the
product
separator 80. Once in the chamber 20, the oil feedstock 50 (which has had the
heavy
metals/napthenic acids removed) may then be reacted with a third quantity of
the
alkali metal 55c. This reaction with the third quantity of the alkali metal
55c
removes at least one heteroatom (e.g., N, S) from the feedstock 50 to form an
upgraded oil feedstock. The heteroatom to carbon ratio of the upgraded oil
feedstock
is less than a heteroatom to carbon ratio of the oil feedstock. Once again,
this product
may then pass through a product separator 80 to remove the inorganic materials
and/or N, S moieties from the oil feedstock, thereby resulting in an upgraded
oil
feedstock.
[0081] It should be noted that the alkali metal quantities 55a, 55b, 55c in
Figure 5
were introduced using the method of the device 100-e.g., by having alkali
metal ions
pass through the ion separator 25 and then be reduced to the metallic state in
situ
within the chamber 20. Of course, other embodiments may be designed in which
one
or more of the alkali metal quantities 55a, 55b, 55c are introduced directly
into the oil
feedstock 50 (e.g., without having the metal be formed via a reduction
reaction). The
different quantities of the alkali metals 55a, 55b, 55c may be the same alkali
metal or
may be different alkali metals.
[0082] Referring now to Figure 6, a flow diagram of a method 190 that may be
used
to upgrade a quantity of a first oil feedstock 50a is shown. Specifically, the
quantity of
the oil feedstock 50 may be obtained. This oil feedstock 50 may include
quantities of
heavy metals, acids (such as napthenlic acid), and/or one or more heteroatoms
(such
CA 2997472 2018-03-05
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as sulfur and nitrogen moieties). In order to upgrade the oil feedstock 50a,
these
metals/heteroatoms/acids may be removed from the oil feedstock 50a.
Specifically,
the quantity of the oil feedstock 50a may be added to a chamber 1 1 Oa. This
chamber 1 10a may be referred to as a "de-metalization" chamber in that the
heavy
metals are removed from the oil feedstock 50a in this chamber 1 10a. In some
embodiments, the chamber 1 10a may be an oil feedstock chamber 20 of the type
described above. However, in other embodiments, the chamber 1 10a may simply
be
another type of vessel that is designed to remove metals from the oil
feedstock 50a.
In order to remove the metals from the oil feedstock 50a, a quantity of alkali
metals
(such as alkali metals 55a shown in Figure 5) may be added to the feedstock
50a.
Once the reaction has occurred, the products may be placed within a product
separator 80a. Those skilled in the art will appreciate the types of devices
(such as a
settling chamber) that may be used as the product separator 80a. In this
product
separator 80a, heavy metals 125 are separated out, leaving only a quantity of
"de-
metalized" oil feedstock 50b.
[0083] This oil feedstock 50b may then be added to a chamber 1 10b. The
chamber 1
10b may be the same chamber as the chamber 1 10a (e.g., the oil feedstock
material
is re-inserted into the chamber 1 10a) or it may be a different vessel. The
chamber 1
10b may be referred to as a "de-acidification" chamber in that the oil
feedstock 50b
may be de-acidified in this chamber 1 10b. In order to conduct this reaction,
the oil
feedstock 50b is reacted with a quantity of an alkali metal (such as second
quantity of
the alkali metal 55b shown in Figure 5). This reaction with the alkali metal
55b reacts
with the napthenic acid in the feedstock 50b. More specifically, the alkali
metal 55b
eliminates the naphtenic acid such that the reacted oil feedstock has a TAN
value
that is less than the TAN value of the (unreacted) oil feedstock 50a.
[0084] Once the reaction has occurred, the products may be placed within a
product
separator 80b. Those skilled in the art will appreciate the types of devices
(such as a
settling chamber) that may be used as the product separator 80b. The product
separator 80b may be the same structure as the product separator 80a or may be
a
different element. In this product separator 80b, inorganic acid products 127
are
separated out, leaving only a quantity of "de-acidified" oil feedstock 50c.
[0085] This de-acidified oil feedstock 50c (which has also been de-metalized)
may
then be added to a chamber 1 10c. This chamber 1 10c may be the same as either
or
CA 2997472 2018-03-05
=
23
both of the chambers 1 10a, 1 10b, or in other embodiments, the chamber 11 Oc
may
be a different chamber than the chambers 1 10a, 11 Ob. This chamber 11 Oc may
be
referred to as a "de-sulfurization" chamber in that sulfur moieties from the
oil
feedstock may be removed. More specifically, an alkali metal (such as a third
quantity
of the alkali metal 55c) may be added to react with the oil feedstock. More
specifically, this reaction involves reacting the alkali metal with a
heteroatom, such as
sulfur. (This reaction is described above). Once reacted, the products may be
added
to a product separator 80c which operates to remove inorganic sulfur products
129
from the oil feedstock, thereby producing de-sulfurized feedstock 50d.
[0086] This feedstock 50d may further be added to a chamber 1 10d. This
chamber 1
10d may be the same as or different than the chambers 1 10a, 1 10b, 1 10c. In
this
chamber, heteroatoms such as nitrogen are removed from the oil feedstock by
reacting the feedstock with an alkali metal quantity (such as, for example,
alkali metal
55c of Figure 5). After this reaction has occurred, the inorganic nitrogen
products 131
may be removed via product separator 80d (which may be the same as, or a
different
structure than, the product separators 80a, 80b, 80c). The resulting oil
feedstock,
after all of these products have been removed, may be classified as an
"upgraded" oil
feedstock 50e.
[0087] In the embodiment shown in Figure 6, the reactions with the sulfur
moieties
and the nitrogen moieties (e.g., heteroatoms) are shown as different steps.
Those
skilled in the art will recognize that other embodiments may involve a single
step
(e.g., a single addition of a third quantity of an alkali metal) to eliminate
all of the S
and N heteroatoms. If the sulfur and nitrogen are eliminated together via a
single
addition of alkali metal, embodiments may be designed in which up to 80% of
the
sulfur may be removed from the oil feedstock before the nitrogen moieties
begin to
react with the alkali metal. It is also understood that depending on the
actual
operating conditions and nature of the feedstock, the order in which the
various
species are removed may differ from the order illustrated in Figure 6.
[0088] Referring now to Figure 7, another embodiment of a system 200 for
upgrading
an oil feedstock is shown. It should be noted that the system 200 includes
many of
the same features that are associated with the device 1 00 of Figure 3. For
purposes
of brevity, much of this discussion will be omitted. However, for clarity, the
wires 42
and the power source 40 are not shown in Figure 7. However, those skilled in
the art
CA 2997472 2018-03-05
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will appreciate that such structures are indeed present and may be necessary
in
order to conduct the electrolytic reactions associated with the system 200.
[0089] In the embodiment of Figure 7, a quantity of a first oil feedstock 150a
is added
to a TAN reduction chamber 205. This chamber 205 is a chamber into which an
alkali
metal (in its metallic form) may be added. This addition of the alkali metal
to the
feedstock 150a operates to eliminate naphthenic acid in the feedstock 150a.
Accordingly, the TAN value of the feedstock 150a after it has been reacted in
the
TAN reduction vessel 205 is significantly reduced. A separator (which is not
shown in
Figure 7) may be used to remove the formed inorganic materials from the
feedstock.
The feedstock leaving this chamber 205 may be referred to as de-acidified oil
feedstock 150b.
[0090] The de-acidified feedstock 150b may be added to a chamber 20 so that it
may
be exposed to alkali metal 155b, thereby eliminating the heteroatoms and/or
the
heavy metals in the feedstock 150b. Thus, Figure 7 shows an embodiment in
which
the chamber 205 used to reduce the TAN value is separate from the chamber 20
that
is used to de-nitrogenize/de-sulfurize the feedstock. Thus, as shown by Figure
7, the
temperature and pressure and flow rate for optimal TAN reduction may be used
in the
TAN vessel 205, and then different temperatures/pressures/flow rates, etc. may
be
used in the chamber 20 for the other chemical reactions. These different
temperatures/pressures/flow rates may be matched to the reaction kinetics of
the
specific reactions.
[0091] The embodiment shown in Figure 7 illustrates that there is a
significant amount
of flexibility associated with the present embodiments. For example, as shown
in
Figure 7, there may be a TAN reduction chamber 205 that is designed to reduce
the
TAN value of the oil feedstock. Once this TAN value has been reduced (for
example
to a value that is less than or equal to 1 ), then other processes may be used
to
eliminate the heteroatoms, heavy metals, etc. associated with the oil
feedstock. Thus,
the owner of the oil feedstock can design a system that will be appropriate
for
processing their particular sample of hydrocarbon material.
[0092] Once the heteroatoms/heavy metals have been removed by the chamber 20,
the oil feedstock 150c may flow out of the chamber 20. This oil feedstock will
be
referred to as "upgraded" oil feedstock 150c.
CA 2997472 2018-03-05
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[0093] Further, those skilled in the art will appreciate that the amount of
alkali metal
that is needed to reduce the TAN value below 1 , to remove the heteroatoms, to
react
with the heavy metals, etc., will depend upon the particular sample of oil
feedstock/hydrocarbon material. Accordingly, by performing testing on the
sample oil
feedstock, a skilled artisan can determine how much alkali metal may be needed
to
upgrade the oil feedstock.
CA 2997472 2018-03-05
