U.S. patent application number 11/966708 was filed with the patent office on 2009-07-02 for upgrading heavy hydrocarbon oils.
This patent application is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Zunquing He, Lin Li, Alberto Montesi, Lee D. Rhyne.
Application Number | 20090166261 11/966708 |
Document ID | / |
Family ID | 40796817 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090166261 |
Kind Code |
A1 |
Li; Lin ; et al. |
July 2, 2009 |
UPGRADING HEAVY HYDROCARBON OILS
Abstract
A process using supercritical water-oil emulsion to upgrade a
heavy hydrocarbon feedstock into an upgraded hydrocarbon product or
syncrude with highly desirable properties (low sulfur content, low
metals content, lower density (higher API), lower viscosity, lower
residuum content, etc.) is disclosed. The process does not require
external supply of hydrogen nor does it use externally supplied
catalysts.
Inventors: |
Li; Lin; (Albany, CA)
; Montesi; Alberto; (Houston, TX) ; Rhyne; Lee
D.; (Cypress, TX) ; He; Zunquing; (San Rafael,
CA) |
Correspondence
Address: |
CHEVRON CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron U.S.A. Inc.
|
Family ID: |
40796817 |
Appl. No.: |
11/966708 |
Filed: |
December 28, 2007 |
Current U.S.
Class: |
208/177 |
Current CPC
Class: |
C10G 31/08 20130101 |
Class at
Publication: |
208/177 |
International
Class: |
C10G 31/00 20060101
C10G031/00 |
Claims
1. A process for upgrading hydrocarbons comprising: (a) mixing
hydrocarbons with a fluid comprising water in a mixing zone to form
an emulsion; (b) heating the emulsion to a temperature higher than
the critical temperature of water; (c) reacting the emulsion in a
reaction zone under supercritical water conditions in the absence
of externally added hydrogen and externally supplied catalyst for a
residence time sufficient to allow upgrading reactions to occur;
(d) withdrawing a single-phase reaction product from the reaction
zone; and (e) separating the reaction product into gas, effluent
water, and upgraded hydrocarbon phases.
2. A process according to claim 1, wherein the hydrocarbons are
heavy hydrocarbons selected from the group consisting of whole
heavy petroleum crude oil, tar sand bitumen, heavy hydrocarbon
fractions obtained from crude petroleum oils, heavy vacuum gas
oils, vacuum residuum, petroleum tar, coal tar and their
mixtures.
3. A process according to claim 1, wherein the emulsion has oil to
water ratio of from 10:1 to 1:5.
4. A process according to claim 1, wherein the conditions in the
mixing zone include a temperature higher than the critical
temperature of water and a pressure greater than the critical
pressure of water.
5. A process according to claim 1, wherein the supercritical water
conditions include a temperature from 374.degree. C. to
1000.degree. C., a pressure from 3,205 psia to 10,000 psia an
oil/water volume ratio from 1:0.1 to 1:10 and where the residence
time is from 1 minute to 6 hours.
6. A process according to claim 1, wherein the supercritical water
conditions include a temperature from 374.degree. C. to 600.degree.
C., a pressure from 3,205 psia to 7,200 psia, an oil/water volume
ratio from 1:0.5 to 1:3 and where the residence time is from 8
minutes to 2 hours.
7. A process according to claim 1, wherein the supercritical water
conditions include a temperature from 374.degree. C. to 400.degree.
C., a pressure from 3,205 psia to 4,000 psia, an oil/water volume
ratio from 1:1 to 1:2 and where the residence time is from 10 to 40
minutes.
8. A process according to claim 1, wherein the mixture in the
reaction zone is reacted in the absence of any catalyst or
promoter.
9. A process according to claim 1, wherein the water is drinking
water, treated wastewater, untreated wastewater, river water, lake
water, seawater, produced water or their mixtures.
10. A process according to claim 1, wherein a surfactant or
emulsifier is added to the mixing zone in step (a)
11. A process according to claim 1, wherein an oil-water emulsion
is formed using a micro-channel mixer in step (a)
12. A process according to claim 1, wherein an oil-water emulsion
is water-in-oil
13. A process according to claim 1, wherein an oil-water emulsion
is oil-in-water
Description
FIELD OF THE INVENTION
[0001] The present invention relates to upgrading of heavy
hydrocarbons such as whole heavy oil, bitumen, and the like using
supercritical water.
BACKGROUND OF THE INVENTION
[0002] Oil produced from a significant number of oil reserves
around the world is simply too heavy to flow under ambient
conditions. This makes it challenging to bring remote, heavy oil
resources closer to the markets. One typical example is the Hamaca
field in Venezuela. In order to render such heavy oils flowable,
one of the most common methods known in the art is to reduce the
viscosity and density by mixing the heavy oil with a sufficient
diluent. The diluent may be naphtha, or any other stream with a
significantly higher API gravity (i.e., much lower density) than
the heavy oil.
[0003] For a case such as Hamaca, diluted crude oil is sent from
the production wellhead via pipeline to an upgrading facility. Two
key operations occur at the upgrading facility: (1) the diluent
stream is recovered and recycled back to the production wellhead in
a separate pipeline, and (2) the heavy oil is upgraded with
suitable technology known in the art (coking, hydrocracking,
hydrotreating, etc.) to produce higher-value products for market.
Some typical characteristics of these higher-value products
include: lower sulfur content, lower metals content, lower total
acid number (TAN), lower residuum content, higher API gravity, and
lower viscosity. Most of these desirable characteristics are
achieved by reacting the heavy oil with hydrogen gas at high
temperatures and pressures in the presence of a catalyst. In the
case of Hamaca, the upgraded crude is sent further to the end-users
via tankers.
[0004] These diluent addition/removal processes and
hydrogen-addition or other upgrading processes have a number of
disadvantages: [0005] 1. The infrastructure required for the
handling, recovery, and recycle of diluent could be expensive,
especially over long distances. Diluent availability is another
potential issue. [0006] 2. Hydrogen-addition processes such as
hydrotreating or hydrocracking require significant investments in
capital and infrastructure. [0007] 3. Hydrogen-addition processes
also have high operating costs, since hydrogen production costs are
highly sensitive to natural gas prices. Some remote heavy oil
reserves may not even have access to sufficient quantities of
low-cost natural gas to support a hydrogen plant. These
hydrogen-addition processes also generally require expensive
catalysts and resource intensive, catalyst handling techniques,
including catalyst regeneration. [0008] 4. In some cases, the
refineries and/or upgrading facilities that are located closest to
the production site may have neither the capacity nor the
facilities to accept the heavy oil. [0009] 5. Coking is often used
at refineries or upgrading facilities. Significant amounts of
by-product solid coke are rejected during the coking process,
leading to lower liquid hydrocarbon yield. In addition, the liquid
products from, a coking plant often need further hydrotreating.
Further, the volume of the product from the coking process is
significantly less than the volume of the feed crude oil.
[0010] A process according to the present invention overcomes these
disadvantages by using supercritical water to upgrade a heavy
hydrocarbon feedstock into an upgraded hydrocarbon product or
syncrude with highly desirable properties (low sulfur content, low
metals content, lower density (higher API), lower viscosity, lower
residuum content, etc.). The process neither requires external
supply of hydrogen nor must it use catalysts. Further, the process
in the present invention does not produce an appreciable coke
by-product.
[0011] In comparison with the traditional processes for syncrude
production, advantages that may be obtained by the practice of the
present invention include a high liquid hydrocarbon yield; no need
for externally-supplied hydrogen; no need to provide catalyst;
significant increases in API gravity in the upgraded hydrocarbon
product; significant viscosity reduction in the upgraded
hydrocarbon product; and significant reduction in sulfur, metals,
nitrogen, TAN, and MCR (micro-carbon residue) in the upgraded
hydrocarbon product.
[0012] Various methods of treating heavy hydrocarbons using
supercritical water are disclosed in the patent literature.
Examples include U.S. Pat. Nos. 3,948,754, 3,948,755, 3,960,706,
3,983,027, 3,988,238, 3,989,618, 4,005,005, 4,151,068, 4,557,820,
4,559,127, 4,594,141, 4,840,725, 5,611,915, 5,914,031 and 6,887,369
and EP671454.
[0013] U.S. Pat. No. 4,840,725 discloses a process for conversion
of high boiling liquid organic materials to lower boiling materials
using supercritical water in a tubular continuous reactor. The
water and hydrocarbon are separately preheated and mixed in a
high-pressure feed pump just before being fed to the reactor.
[0014] U.S. Pat. No. 6,887,369 discloses a supercritical water
pretreatment process using hydrogen or carbon monoxide preferably
carried out in a deep well reactor to hydrotreat and hydrocrack
carbonaceous material. The deep well reactor is adapted from
underground oil wells, and consists of multiple, concentric tubes.
The deep well reactor described in the patent is operated by
introducing feed streams in the core tubes and returning reactor
effluent in the outer annular section.
SUMMARY OF THE INVENTION
[0015] The present invention relates to a process for upgrading
hydrocarbons comprising mixing hydrocarbons with a fluid comprising
water in a mixing zone to form an emulsion; heating the emulsion to
a temperature above the critical temperature of water; reacting the
emulsion in a reaction zone under supercritical water conditions in
the absence of externally added hydrogen for a residence time
sufficient to allow upgrading reactions to occur; withdrawing a
single-phase reaction product from the reaction zone; and
separating the reaction product into gas, effluent water, and
upgraded hydrocarbon phases.
BRIEF DESCRIPTION OF THE DRAWING
[0016] FIG. 1 is a process flow diagram of an embodiment of the
present invention.
[0017] FIG. 2 is a process flow diagram of an embodiment of the
present invention.
[0018] FIG. 3 is a process flow diagram of an embodiment of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The present process is related to processes described in
commonly assigned U.S. patent application Ser. Nos. 11/555,048;
11/555,130; 11/555,196; and 11/555,211, all of which were filed on
Oct. 31, 2006 and which are incorporated by reference herein. These
patent applications relate to various aspects of heavy oil
upgrading technology using supercritical water. The present
disclosure also relates to processes using supercritical water to
upgrade hydrocarbons and in a way to make fuller use of the
potential of supercritical water and minimize by products produced
by side reactions by focusing on the solvent oil mixing and
contacting. This is accomplished by using the herein disclosed
technology to enhance solvent-oil mixing/contacting through
formation of emulsion so that the performance of upgrading process
can be significantly improved.
Reactants
[0020] Water and hydrocarbons, preferably heavy hydrocarbons are
the two reactants employed in a process according to the present
invention.
[0021] Any heavy hydrocarbon can be suitably upgraded by a process
according to the present invention. Preferred are heavy
hydrocarbons having an API gravity of less than 20.degree.. Among
the preferred heavy hydrocarbons are heavy crude oil, heavy
hydrocarbons extracted from tar sands, commonly called tar sand
bitumen, such as Athabasca tar sand bitumen obtained from Canada,
heavy petroleum crude oils such as Venezuelan Orinoco heavy oil
belt crudes, Boscan heavy oil, heavy hydrocarbon fractions obtained
from crude petroleum oils, particularly heavy vacuum gas oils,
vacuum residuum as well as petroleum tar, tar sands and coal tar.
Other examples of heavy hydrocarbon feedstocks which can be used
are oil shale, shale oil, and asphaltenes.
Water
[0022] Any source of water may be used in the fluid comprising
water in practicing the present invention. Sources of water include
but are not limited to drinking water, treated or untreated
wastewater, river water, lake water, seawater produced water or the
like.
[0023] Mixing/Emulsion Formation
[0024] A heavy hydrocarbon feed and the fluid comprising water are
contacted in a mixing zone to form an emulsion prior to entering
the reaction zone.
[0025] Forming an emulsion allows the present process to utilize
the advantage of the high interfacial area of emulsions to improve
water-oil contacting. As it was pointed in the above-identified
related applications, surroundings the heavy hydrocarbon molecules
by water molecules during heating and reaction processes avoids
over cracking the hydrocarbon feed into light hydrocarbons and
polymerizing the hydrocarbon feed into coke.
[0026] One way to achieve the goal of surrounding the heavy
hydrocarbon molecules by water molecules is to form an emulsion,
i.e. a kinetically or thermodynamically stable dispersion of an oil
phase and an aqueous phase, with or without added surfactant. The
high interfacial area of emulsion will provide sufficient contact
and mixing of oil with water to achieve a high yield of liquid
hydrocarbons.
[0027] For applications of emulsion technology generally, one big
challenge is breaking the emulsion when needed to achieve phase
separation after the emulsion has served the purpose for which it
was formed. The technical and economic challenges of
emulsion-breaking technology has prevented emulsion technology from
being used more broadly because the costs of breaking up the
emulsion to separate the target product often outweigh the benefits
of performance enhancement provided by emulsion. However, for heavy
oil upgrading using supercritical water as herein described, the
emulsion is destroyed during the upgrading process through
vaporization of the water and release of hydrocarbon product.
Therefore, in accordance with the present process the advantages of
emulsion use are obtained having to incur the costs associated with
the application of breaking, the emulsion to separate the
product.
[0028] The structure and droplet size of the emulsion can be
optimized based on process performance requirement and operation
cost. There are several ways to form water-oil emulsion known to
those of ordinary skill in this technology including high shear
equipment such as nozzle, etc. Surfactants or other agents
(emulsifiers) may be needed to form a stable emulsion with required
structure and droplet size. The emulsion may be either an
oil-in-water emulsion or a water-in-oil emulsion.
[0029] A surfactant or a mix of surfactants may be included in the
heavy oil/water feedstock emulsion to increase the stability of the
emulsion. Suitable surfactants include both water and oil soluble
surfactants. A suitable surfactant or mixtures of surfactants
include surfactants having a hydrophilic-lipophilic balance in the
range of between about 2 and about 10 and mixtures thereof. When a
single surfactant is used, sufficient amounts are used to obtain a
stable emulsion. Typically this concentration of single surfactant
falls in the range of between about 50 ppm and about 2% of the
emulsion. It has been found that when a combination of surfactants
is used, the total amount of surfactant added is typically less
than the amount used for any single surfactant. Thus, when a
combination of surfactants are used to achieve a stabilized
emulsion, the total surfactant concentration typically falls in the
range of between about 100 ppm and about 1% of the emulsion.
Suitable emulsifiers include fatty acid soaps such as calcium
dioleate, fatty amides such as the reaction products of oleic acid
and diethylamine thiamine, a variety of polymeric emulsifiers
containing alcohol or carboxylic acid groups or organophilic clays,
and certain organic-silicone-based polymers.
[0030] FIG. 1 shows one embodiment. The water and oil are pumped to
a mixer where an oil-in-water emulsion is formed. In an embodiment
the emulsion has a ratio of oil to water from 10:1 to 1:5. The
oil-in-water emulsion; can be prepared in any convenient way
suitable for making a fine dispersion of an aqueous phase in a
continuous oil phase, but preferably it is prepared by strong
physical agitation of the aqueous and oil components optionally in
the presence of a suitable oil-in-water emulsifier. Other ways to
form oil-water emulsions include using a micro channel mixer or
high shear equipment such as nozzles, etc. As noted previously,
surfactants or other agents may be needed to form a stable emulsion
with the required structure and droplet size.
[0031] Considering the high viscosity of the feed oil, a pre-heater
may be needed to heat the oil to certain temperature to facilitate
the emulsion formation. The temperature of heavy oil feed should be
kept in the range of about 100.degree. to 200.degree. C. to avoid
thermal cracking but still high enough to maintain reasonable
pressure drop. The oil-in-water emulsion will have lower viscosity
than feed oil (heavy oil), and its flow behavior will be more
similar to water than feed oil. It is obvious that lower viscosity
is advantageous to lower power consumption for pumps. Other
advantages of having water as the external, continuous phase will
include reduced fouling of the pipes and reactor from the oil
phase, and improved heat transfer to the reactor feed.
[0032] The oil-in-water emulsion is sent to heater to be heated up
to temperature required for oil upgrading (higher than
supercritical water conditions). Oil-in-water emulsion provide very
high interfacial area for water-oil contact, and this is of
critical importance to achieve high upgrading performance because
the abundance of water molecules surrounding the hydrocarbon
molecules will significantly suppress condensation reactions and
therefore reduce formation of coke and solid product.
[0033] FIG. 2 shows another embodiment. A second water stream is
added to the process so that water to oil ratio for emulsion
formation and for the upgrading process can be adjusted
independently to optimize the performance. The temperature of
second water stream can also be adjusted to achieve optimized
performance. The viscosity of oil-in-water emulsion would be much
lower than feed oil, which makes the mixing of those two streams
much easier.
[0034] FIG. 3 shows yet another embodiment. Water-in-oil emulsion,
which also has the advantage of high water-oil interfacial area,
was formed at the mixer. Then the emulsion will meet with and
heated up by a water stream with temperature higher then critical
point. Since the water has a lower boiling point than feed oil,
water inside the oil shell will quickly evaporate to break up the
oil shell and therefore achieve very good water-oil mixing.
Reaction Conditions
[0035] After the reactants have been mixed to form an emulsion,
they are passed into a reaction zone in which they are allowed to
react under temperature and pressure conditions of supercritical
water, i.e. supercritical water conditions, in the absence of
externally added hydrogen, for a residence time sufficient to allow
upgrading reactions to occur. The reaction is preferably allowed to
occur in the absence of externally added catalysts or promoters,
although the use of such catalysts and promoters is permissible in
accordance with the present invention.
[0036] "Hydrogen" as used herein in the phrase, "in the absence of
externally added hydrogen" means hydrogen gas. This phrase is not
intended to exclude all sources of hydrogen that are available as
reactants. Other molecules such as saturated hydrocarbons may act
as a hydrogen source during the reaction by donating hydrogen to
other unsaturated hydrocarbons. In addition, H.sub.2 may be formed
in-situ during the reaction through steam reforming of hydrocarbons
and water-gas-shift reaction.
[0037] The reaction zone preferably comprises a reactor, which is
equipped with a means for collecting the reaction products
(syncrude, water, and gases), and a bottom section where any metals
or solids (the "dreg stream") may accumulate.
[0038] Supercritical water conditions include a temperature from
374.degree. C. (the critical temperature of water) to 1000.degree.
C., preferably from 374.degree. C. to 600.degree. C. and most
preferably from 374.degree. C. to 400.degree. C., a pressure from
3,205 (the critical pressure of water) to 10,000 psia, preferably
from 3,205 psia 7 to 7,200 psia and most preferably from 3,205 to
4,000 psia, an oil/water volume ratio from 1:0.1 to 1:10,
preferably from 1:0.5 to 1:3 and most preferably about 1:1 to
1:2.
[0039] The reactants are allowed to react under these conditions
for a sufficient time to allow upgrading reactions to occur.
Preferably, the residence time will be selected to allow the
upgrading reactions to occur selectively and to the fullest extent
without having undesirable side reactions of coking or residue
formation. Reactor residence times may be from 1 minute to 6 hours,
preferably from 8 minutes to 2 hours and most preferably from 10 to
40 minutes.
Reaction-Product Separation
[0040] After the reaction has, progressed sufficiently, a single
phase reaction product is withdrawn from the reaction zone, cooled,
and separated into gas, effluent water, and upgraded hydrocarbon
phases. This separation is preferably done by cooling the stream
and using one or more two-phase separators, three-phase-separators,
or other gas-oil-water separation device-known in the art. However,
any method of separation can be used in accordance with the
invention. As noted previously, the emulsion has been broken as a
result of the very high temperature reaction.
[0041] The composition of gaseous product obtained by treatment of
the heavy hydrocarbons in accordance with the process of the
present invention will depend on feed properties and typically
comprises light hydrocarbons, water vapor, acid gas (CO.sub.2 and
H.sub.2S), methane and hydrogen. The effluent water may bemused,
reused or discarded. It may be, recycled to e.g. the feed water
tank, the feed water treatment system or to the reaction zone.
[0042] The upgraded hydrocarbon product, which is sometimes
referred to as "syrcrude" herein may be upgraded further or
processed into other hydrocarbon products using methods that are
known in the hydrocarbon processing art.
[0043] The process of the present invention may be carried out as a
continuous or semi-continuous process or a batch, process. In the
continuous process the entire system operates with a feed stream of
oil and a separate feed stream of water and reaches a steady state;
whereby all the flow rates, temperatures, pressures, and
composition of the inlet, outlet, and recycle streams do not vary
appreciably with time.
[0044] While not being bound to any theory of operation, it is
believed that a number of upgrading reactions are occurring
simultaneously at the supercritical reaction conditions used in the
present process.
[0045] In a preferred embodiment of the invention the major
chemical/upgrading reactions are believed to be:
[0046] Thermal Cracking C.sub.xH.sub.y.fwdarw.lighter
hydrocarbons
[0047] Steam Reforming:
C.sub.xH.sub.y+2xH.sub.2O=xCO.sub.2+(2x+y/2)H.sub.2
[0048] Water-Gas-Shift: CO+H.sub.2O.dbd.CO.sub.2+H.sub.2
[0049] Demetalization:
C.sub.xH.sub.yNi.sub.w+H.sub.2O/H.sub.2.fwdarw.NiO/Ni(OH).sub.2+lighter
hydrocarbons
[0050] Desulfurization:
C.sub.xH.sub.yS.sub.z+H.sub.2O/H.sub.2.dbd.H.sub.2S+lighter
hydrocarbons
[0051] The exact pathway may depend on the reactor operating
conditions (temperature, pressure, O/W volume ratio), reactor
design (mode of contact/mixing, sequence of heating), and the
hydrocarbon feedstocks
[0052] The following Examples are illustrative of the present
invention, but are not intended to limit the invention in any way
beyond what is contained in the claims which follow.
EXAMPLES
Example 1
Heavy Oil Upgrading Using Emulsion Mixing
[0053] The experiment was performed using a continuous system. A
feed oil, which was a heavy crude with API=12.8, which was diluted
with a diluent hydrocarbon at a ratio of 5:1 (20 vol % of diluent)
and water was heated to 150.degree. C. before entering a
micromixer. The heated crude was mixed with water in the micromixer
to form a water-oil emulsion, which was injected into a stream of
supercritical water at temperature of 400.degree. C. The total
water to oil ratio (volume at room temperature) was 3:1. The
oil-supercritical water mixture was then injected into a reactor at
temperature of 400.degree. C. and pressure, of 3400 psig. The
upgraded product, which formed a homogeneous phase with
supercritical water, was withdrawn from the top of the reactor and
send to high pressure separator which was operated at the same
pressure but lower temperature to achieve oil-water separation. The
dreg stream was removed from reactor bottom.
[0054] The diluted heavy crude oil properties were measured before
reacting it with the supercritical water process as referred to in
Example 1. The properties of the crude were as follows: 12.8 API
gravity at 60/60; 1329 CST viscosity @40.degree. C.; 13.04 wt %
MCRT; 3.54 wt % sulfur; 0.56 wt % nitrogen; 3.05 mg KOH/gm acid
number; 1.41 wt % water; 371 ppm Vanadium; and 86 ppm Nickel. The
diluted heavy crude oil after the super critical water treatment
was converted into a syncrude with the following properties: 23.4
API gravity at 60/60; 9.8 CST viscosity @40.degree. C.; 1.9 wt %
MCRT; 2.7 wt % sulfur; 2.41 mg KOH/gm acid number; 88% Vanadium
reduction; and 93% Nickel reduction.
[0055] Based on reactor volume and liquid yield it was calculated
that the liquid productivity was 15.61 lb/ft3.h.
Example 2
Reference Run Using In-Line Mixer
[0056] In order to demonstrate the improved performance by using
emulsion mixing, a reference run using in-line mixer to mix water
and oil was performed under the same operation conditions
(temperature, pressure, water to oil ratio). Feed oil (diluted
heavy crude of Example 1) was preheated to 130 C, and then mixed
with supercritical water in an inline mixer. Water-oil stream flow
through a 20 ft spiral coil immersed in a high temperature sand
bath (same as reactor temperature) to further improve water-oil
contact, and then fed to the reactor. The upgraded product, which
formed a homogeneous phase with supercritical water, was withdrawn
from the top of the reactor and send to high pressure separator
which was operated at the same pressure but lower temperature to
achieve oil-water separation. The dreg stream was removed from
reactor bottom.
[0057] The liquid product (syncrude) from this reference run has
the following properties: 22 API gravity at 60/60; 14.7 CST
viscosity @40.degree. C.; 1.99 wt % MCRT; 2.74 wt % sulfur; 3.0 mg
KOH/gm acid number; 86% Vanadium reduction; and 91% Nickel
reduction. Overall the product quality is comparable with those
obtained in Example 1. However, in order to achieve upgraded
product with such quality, much longer residence time was needed.
As a result, the liquid productivity for this was 9.2 lb/ft3.h.
[0058] By comparing results of the above two examples, it is clear
that under similar operation conditions (pressure, temperature and
water to oil) by using emulsion mixing the upgrading process can be
significantly enhanced, demonstrated by improved liquid yield at
shorter residence time while maintaining same product quality. In
comparing with experimental results using in-line mixer and spiral
coil or oil-ater mixing, the application of emulsion mixing fled to
a 80% increase of upgraded liquid, productivity (defined as lb
upgraded liquid/(ft3.h)) while maintaining the same product quality
(API, viscosity, metal removing rate etc.)
[0059] There are numerous variations on the present invention which
are possible in light of the teachings and supporting examples
described herein. It is therefore understood that within the scope
of the following claims, the invention may be practiced otherwise
than as specifically described or exemplified herein.
* * * * *