U.S. patent application number 16/946823 was filed with the patent office on 2022-01-13 for online analyzer for biofuel production.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Maria Vanessa C. Aguinaldo, Samuel J. Cady, John Della Mora, Shifang Luo, Kegun L. Ream, Michael H. Ring, Chengrong Wang, Xiaochun Xu, Anding Zhang.
Application Number | 20220010219 16/946823 |
Document ID | / |
Family ID | 1000005065312 |
Filed Date | 2022-01-13 |
United States Patent
Application |
20220010219 |
Kind Code |
A1 |
Wang; Chengrong ; et
al. |
January 13, 2022 |
ONLINE ANALYZER FOR BIOFUEL PRODUCTION
Abstract
Disclose is an online analyzer to monitor conversion of a
biofeedstock in a first hydrotreating stage to avoid catalyst
poisoning in a subsequent stage. An example method of processing a
biofeedstock may comprise hydrotreating the biofeedstock by
reaction with hydrogen to form a hydrotreated biofeedstock. The
method may further comprise monitoring conversion of the
biofeedstock in the hydrotreating with an online analyzer.
Inventors: |
Wang; Chengrong; (Easton,
PA) ; Zhang; Anding; (Short Hills, NJ) ; Xu;
Xiaochun; (Basking Ridge, NJ) ; Cady; Samuel J.;
(Morristown, NJ) ; Luo; Shifang; (Annandale,
NJ) ; Ring; Michael H.; (Conroe, TX) ;
Aguinaldo; Maria Vanessa C.; (Katy, TX) ; Della Mora;
John; (North York, CA) ; Ream; Kegun L.;
(Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
1000005065312 |
Appl. No.: |
16/946823 |
Filed: |
July 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10L 2200/0476 20130101;
C10G 3/50 20130101; C10G 2300/1011 20130101; C10L 1/04 20130101;
G01J 3/2823 20130101 |
International
Class: |
C10G 3/00 20060101
C10G003/00; C10L 1/04 20060101 C10L001/04; G01J 3/28 20060101
G01J003/28 |
Claims
1. A method of processing a biofeedstock, comprising: hydrotreating
the biofeedstock by reaction with hydrogen to form a hydrotreated
biofeedstock; monitoring conversion of the biofeedstock in the
hydrotreating with an online analyzer; and controlling recycle of
the hydrotreated biofeedstock to the hydrotreating in response to
the monitoring conversation of the biofeedstock.
2. The method of claim 1, wherein the biofeedstock comprises at one
component selected from the group consisting of a vegetable oil, an
animal fat, a fish oil, a pyrolysis oil, algae lipid, an algae oil,
and combinations thereof.
3. The method of claim 1, wherein the biofeedstock comprises lipid
compounds.
4. The method of claim 1, wherein the hydrotreated biofeedstock
comprises paraffin products.
5. The method of claim 1, wherein the online analyzer comprises a
spectrometer.
6. The method of claim 1, wherein the online analyzer is an
infrared spectrometer, a near infrared spectrometer, or a Raman
spectrometer.
7. The method of claim 1, wherein the monitoring conversion of the
biofeedstock comprises determining oxygen removal from the
biofeedstock.
8. The method of claim 1, wherein the monitoring conversion
comprises correlating measurements from the online analyzer with
conversion of the biofeedstock.
9. The method of claim 1, wherein the monitoring conversion
comprises measuring carbonyl group concentration in the
hydrotreated biofeedstock.
10. The method of claim 1, wherein the online analyzer is
positioned between a hydrodeoxygenation reactor and a dewaxing
reactor.
11. The method of claim 1, further comprising contacting at least a
portion of the hydrotreated biofeedstock with a dewaxing catalyst
to produce a renewable diesel product.
12. The method of claim 11, further comprising separating gas-phase
products from the hydrotreated biofeedstock before the contacting
at least the portion of the hydrotreated biofeedstock.
13. The method of claim 1, wherein the controlling recycle
comprises recycling the hydrotreated biofeedstock to the
hydrotreating until the monitoring conversion indicates that about
90 wt. % or more of oxygen is removed from the biofeedstock.
14. The method of claim 1, wherein the controlling recycle
comprises recycling the hydrotreated biofeedstock to the
hydrotreating until the monitoring conversion indicates that about
99 wt. % or more of oxygen is removed from the biofeedstock.
15. The method of claim 1, wherein the controlling recycle
comprises recycling the hydrotreated biofeedstock until a peak
intensity for a carbonyl peak on an infrared spectrum from the
online analyzer is below a set intensity value.
16. A system for production of renewable diesel comprising: a
hydrotreatment stage comprising a hydrodeoxygenation reactor that
receives a biofeedstock; a dewaxing stage comprising a dewaxing
reactor that receives a hydrotreated product stream from the
hydrotreatment stage; an online analyzer positioned to analyze the
hydrotreated product stream to monitor conversion of the
biofeedstock in the hydrotreatment stage; and a controller that
controls recycles of the hydrotreated product stream in response to
measurements from the online analyzer.
17. The system of claim 16, wherein the online analyzer is an
infrared spectrometer, a near infrared spectrometer, or a Raman
spectrometer.
18. (canceled)
19. The system of claim 18, further comprising a recycle valve,
wherein the controller is configured to send control signals to the
recycle valve in response to the measurements from the online
analyzer.
20. The system of claim 16, wherein the online analyzer is
positioned between the hydrodeoxygenation reactor and the dewaxing
reactor.
21. A method of processing a biofeedstock, comprising:
hydrotreating the biofeedstock in a hydrodeoxygenation reactor by
reaction with hydrogen to form a hydrodeoxygenation reactor
effluent stream comprising hydrotreated biofeedstock; monitoring
conversion of the biofeedstock in the hydrotreating with an online
analyzer; controlling recycle of the hydrotreated biofeedstock to
the hydrodeoxygenation reactor in response to the monitored
conversion of the biofeedstock, wherein the hydrotreated
biofeedstock is recycled until a peak intensity for a carbonyl peak
on an infrared spectrum from the online analyzer is below a set
intensity value; and contacting at least a portion of the
hydrotreated biofeedstock with a dewaxing catalyst to isomerize
paraffinic molecules in the hydrotreated biofeedstock.
Description
FIELD OF THE INVENTION
[0001] This application relates to renewable diesel production and,
in particular, embodiments relate to utilization of an online
analyzer to monitor conversion of a biofeedstock in a first
hydrotreating stage to avoid catalyst poisoning in a subsequent
stage.
BACKGROUND OF THE INVENTION
[0002] Renewable diesel is a hydrocarbon fuel made from vegetable
oils, fats, greases, or other suitable biofeedstocks. In contrast
to biodiesels, renewable diesels are not esters and are chemically
similar to petroleum diesels. In some instances, renewable diesel
can be used as a blendstock for blending with petroleum diesel.
While a number of different techniques can be used for renewable
diesel production, an example process includes hydrotreatment of a
biofeedstock followed by dewaxing. Since the dewaxing catalyst can
be sensitive to oxygen, the activity of dewaxing catalyst can be
quickly inhibited or deactivated should the oxygen in the
biofeedstock not be sufficiently converting in the
hydrotreatment.
SUMMARY OF THE INVENTION
[0003] Disclosed herein is an example method of processing a
biofeedstock. The method may comprise hydrotreating the
biofeedstock by reaction with hydrogen to form a hydrotreated
biofeedstock. The method may further comprise monitoring conversion
of the biofeedstock in the hydrotreating with an online
analyzer.
[0004] Disclosed herein a system for production of renewable
diesel. The system may comprise a hydrotreatment stage comprising a
hydrodeoxygenation reactor that receives a biofeedstock. The system
may further comprise a dewaxing stage comprising a dewaxing reactor
that receives a hydrotreated product stream from the hydrotreatment
stage. The system may further comprise an online analyzer
positioned to analyze the hydrotreated product stream to monitor
conversion of the biofeedstock in the hydrotreatment stage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These drawings illustrate certain aspects of the present
disclosure and should not be used to limit or define the
invention.
[0006] FIG. 1 depicts an example renewable diesel production system
in accordance with one or more embodiments.
[0007] FIG. 2 depicts another example renewable diesel production
system in accordance with one or more embodiments.
[0008] FIG. 3 depicts an infrared spectrum of canola oil.
[0009] FIG. 4 depicts an infrared spectrum of an early-stage
product from hydrotreatment in accordance with one or more
embodiments.
[0010] FIG. 5 depicts a gas chromatography-mass spectroscopy
spectrum of an early-stage product from hydrotreatment in
accordance with one or more embodiments.
[0011] FIG. 6 depicts an infrared spectrum of a middle-stage
product from hydrotreatment in accordance with one or more
embodiments.
[0012] FIG. 7 depicts a gas chromatography-mass spectroscopy
spectrum of a middle-stage product from hydrotreatment in
accordance with one or more embodiments.
[0013] FIG. 8 depicts an infrared spectrum of a late-stage product
from hydrotreatment in accordance with one or more embodiments.
[0014] FIG. 9 depicts a gas chromatography-mass spectroscopy
spectrum of a late-stage product from hydrotreatment in accordance
with one or more embodiments.
[0015] FIG. 10 depicts an infrared spectrum of a fully converted
product from hydrotreatment in accordance with one or more
embodiments.
[0016] FIG. 11 depicts a gas chromatography-mass spectroscopy
spectrum of a fully converted product from hydrotreatment in
accordance with one or more embodiments.
DETAILED DESCRIPTION
[0017] This application relates to renewable diesel production and,
in particular, embodiments, relates to utilization of an online
analyzer to monitor conversion of a biofeedstock in a hydrotreating
stage to avoid catalyst poisoning in a subsequent dewaxing stage.
While a variety of online analyzers may be suitable, online
spectrometers may be particularly suitable, in certain embodiments,
for monitoring concentration change of raw materials of the
biofeedstock in the hydrotreating stage.
[0018] In accordance with present embodiments, renewable diesel
production may include a hydrotreating stage. In the hydrotreating
stage, a biofeedstock may be converted by reaction with hydrogen to
form, for example, paraffin products with removal of oxygen.
Particular embodiments for renewable diesel production may further
include a dewaxing stage that receives hydrotreated biofeedstock
from the hydrotreating stage. In the dewaxing stage, the
hydrotreated biofeedstock may be catalytically dewaxed, for
example, by removal and/or isomerization of long chain paraffinic
molecules, such as molecules ranging from 12 carbons long to 24
carbons long or from 16 carbons long to 22 carbons long. However,
catalysts used in the dewaxing stage may be sensitive to oxygen.
Accordingly, if there is insufficient feed conversion in the
hydrotreating stage, the catalyst in the dewaxing stage may
deactivate too quickly.
[0019] To monitor conversion of the biofeedstock in the
hydrotreating stage and avoid potential catalyst poisoning in the
dewaxing stage, example embodiments use an online analyzer, such as
a spectrometer. In some embodiments, the online analyzer may be
positioned between the hydrotreating stage and the dewaxing stage.
The online analyzer may monitor concentration change of the
biofeedstock to determine whether sufficient oxygen has been
removed from the biofeedstock before sending the hydrotreated
biofeedstock to the dewaxing stage. In some embodiments, the
systems and methods may utilize the online analyzer to measure
carbonyl group concentration in the reaction products from the
hydrotreating stage. The use of an online analyzer can provide
several advantages over traditional techniques that use offline
analysis where a sample from the hydrotreating stage is taken to a
lab for analysis. By way example, the online analyzer monitors the
hydrotreating stage in real time with minimal personnel involvement
by process operators. With real time monitoring, process changes
may be implemented to prevent insufficiently converted biofeedstock
with too high oxygen content from poisoning the downstream dewaxing
catalyst. In some embodiments, the hydrotreated biofeedstock can be
recycled to the hydrotreating stage if the online analysis
indicates insufficient conversion.
[0020] Embodiments may include a process for renewable diesel
production. Renewable diesel is a hydrocarbon made from
biofeedstocks, including vegetable oils, fats, greases, or other
sources of triglycerides, which can include various crops, waste
oil, or other animal fats. As used herein, the term "renewable
diesel" refers to a hydrocarbon liquid produced from a biofeedstock
and with paraffins as a major component. Because renewable diesel
is chemically similar to petroleum diesel, renewable diesel is
capable of use in diesel engines without engine modification. In
one example, a renewable diesel includes between about 50% to about
99% by weight of paraffins. A 100% renewable diesel should meet the
ASTM D975 specification for diesel fuel.
[0021] In accordance with present embodiments, the renewable diesel
may be produced from a biofeedstock. Any of a variety of suitable
biofeedstocks may be used in the production of the renewable
diesel. The biofeedstock may be derived from a biological raw
material component such as vegetable, animal, fish, and/or algae.
Suitable biofeedstocks may include, but are not limited to,
vegetable oils, animal fats, fish oils, pyrolysis oils, and algae
lipids/oils, as well as components of such materials, and in some
embodiments can specifically include one or more type of lipid
compounds. As used herein, vegetable fats/oils refer to any
plant-based material and can include fat/oils derived from a source
such as plants of the genus Jatropha. In some embodiments, the
biofeedstock may include biodiesel, also referred to as fatty acid
methyl ester. In some embodiments, the biofeedstock may include
free fatty acids.
[0022] The biofeedstock may include lipid compounds, which are
typically biological compounds that are insoluble in water, but
soluble in nonpolar (or fat) solvents. Non-limiting examples of
such solvents include alcohols, ethers, chloroform, alkyl acetates,
benzene, and combinations thereof. Major classes of lipids include,
but are not necessarily limited to, fatty acids, glycerol-derived
lipids (including fats, oils and phospholipids),
sphingosine-derived lipids (including ceramides, cerebrosides,
gangliosides, and sphingomyelins), steroids and their derivatives,
terpenes and their derivatives, fat-soluble vitamins, certain
aromatic compounds, and long-chain alcohols and waxes. In living
organisms, lipids generally serve as the basis for cell membranes
and as a form of fuel storage. Lipids can also be found conjugated
with proteins or carbohydrates, such as in the form of lipoproteins
and lipopolysaccharides.
[0023] The biofeedstock may include vegetable oils. Examples of
vegetable oils that can be used may include, but are not limited to
rapeseed (canola) oil, soybean oil, coconut oil, sunflower oil,
palm oil, palm kernel oil, peanut oil, linseed oil, tall oil, corn
oil, castor oil, jatropha oil, jojoba oil, olive oil, flaxseed oil,
camelina oil, safflower oil, babassu oil, tallow oil, and rice bran
oil. Vegetable oils as referred to herein can also include
processed vegetable oil material. Non-limiting examples of
processed vegetable oil material include fatty acids and fatty acid
alkyl esters. Alkyl esters typically include C.sub.1-C.sub.5 alkyl
esters. In some embodiments, one or more of methyl, ethyl, and
propyl esters may be used.
[0024] The biofeedstock may include animal fats. Examples of animal
fats that can be used include, but are not limited to, beef fat
(tallow), hog fat (lard), turkey fat, fish fat/oil, and chicken
fat. The animal fats can be obtained from any suitable source
including restaurants and meat production facilities. Animal fats
as referred to herein also include processed animal fat material.
Non-limiting examples of processed animal fat material include
fatty acids and fatty acid alkyl esters. Alkyl esters typically
include C.sub.1-C.sub.5 alkyl esters. In some embodiments, one or
more of methyl, ethyl, and propyl esters may be used.
[0025] The biofeedstock may include algae oils or lipids that may
be typically contained in algae in the form of membrane components,
storage products, and metabolites. Certain algal strains,
particularly microalgae such as diatoms and cyanobacteria, contain
proportionally high levels of lipids. Algal sources for the algae
oils can contain varying amounts, e.g., from 2 weight percent ("wt.
%") to 40 wt. % of lipids, based on total weight of the biomass
itself. Algal sources for algae oils may include, but are not
limited to, unicellular and multicellular algae. Examples of such
algae include a rhodophyte, chlorophyte, heterokontophyte,
tribophyte, glaucophyte, chlorarachniophyte, euglenoid, haptophyte,
cryptomonad, dinoflagellum, phytoplankton, and the like, and
combinations thereof. In one embodiment, algae can be of the
classes Chlorophyceae and/or Haptophyta. Specific species can
include, but are not limited to, Neochloris oleoabundans,
Scenedesmus dimorphus, Euglena gracilis, Phaeodactylum tricornutum,
Pleurochrysis carterae, Prymnesium parvum, Tetraselmis chui, and
Chlamydomonas reinhardtii.
[0026] The biofeedstock may include feedstocks that primarily
include triglycerides and free fatty acids (FFAs). The
triglycerides and FFAs typically contain aliphatic hydrocarbon
chains in their structure having from 8 to 36 carbons, for example,
from 10 to 26 carbons or 14 to 22 carbons. Types of triglycerides
can be determined according to their fatty acid constituents. The
fatty acid constituents can be readily determined using Gas
Chromatography (GC) analysis. This analysis involves extracting the
fat or oil, saponifying (hydrolyzing) the fat or oil, preparing an
alkyl (e.g., methyl) ester of the saponified fat or oil, and
determining the type of (methyl) ester using GC analysis. In one
embodiment, a majority (i.e., greater than 50%) of the triglyceride
present in the lipid material can include C.sub.10 to C.sub.26
fatty acid constituents, based on total triglyceride present in the
lipid material. Further, a triglyceride is a molecule having a
structure substantially identical to the reaction product of
glycerol and three fatty acids. Thus, although a triglyceride is
described herein as being including fatty acids, it should be
understood that the fatty acid component does not necessarily
contain a carboxylic acid hydrogen. In one embodiment, a majority
of triglycerides present in the biocomponent feed can include
C.sub.12 to C.sub.18 fatty acid constituents, based on total
triglyceride content. Other types of feed that are derived from
biological raw material components can include fatty acid esters,
such as fatty acid alkyl esters (e.g., FAME and/or FAEE).
[0027] FIG. 1 is a simplified block diagram illustrating a system
10 for renewable diesel production in accordance with some
embodiments. As illustrated, the system 10 may include the
following stages: (i) a hydrotreating stage 12 in which a biofeed
stream 14 containing a biofeedstock can be reacted with hydrogen
from a hydrogen stream 16 to remove oxygen from the biofeedstock;
and (ii) a dewaxing stage 18 that receives a hydrotreated product
stream 20 containing hydrotreated biofeedstock and catalytically
dewaxes the hydrotreated biofeedstock to produce a renewable diesel
product 22 with improved cold flow properties. As illustrated, an
online analyzer 24 may analyze hydrotreated biofeedstock to monitor
conversion of the biofeedstock in the hydrotreating stage 12 to
products with reduced oxygen content. By way example, the online
analyzer 24 can measure concentration of certain groups (e.g.,
carbonyl groups) in the hydrotreated biofeedstock, which indicates
presence of the biofeedstock or intermediate products. Should there
be insufficient conversion, then oxygen has not been sufficiently
removed which can undesirably interact with the catalyst in the
dewaxing stage 18. Should the oxygen not be sufficiently removed at
least a portion of the hydrotreated biofeedstock can be recycled to
the hydrotreating stage 12 for further reaction. As illustrated, a
controller 26 may operate a recycle valve 28 to control recycle of
the hydrotreated biofeedstock.
[0028] In the hydrotreating stage 12, the biofeed stream 14
containing a biofeedstock may be combined with the hydrogen stream
16 containing hydrogen. While FIG. 1 illustrates separate addition
of the biofeed stream 14 and the hydrogen stream 16 to the
hydrotreating stage 12, embodiments may include combination of the
biofeed stream 14 and the hydrogen stream 16 prior to the
hydrotreating stage 12. The hydrotreating stage 12 should remove
oxygen from the biofeedstock in the biofeed stream 14 by reaction
with hydrogen in the hydrogen stream 16. The reaction in the
hydrotreating stage 12 should produce hydrotreated biofeedstock,
including paraffin products, reaction intermediates, and unreacted
biofeedstock and hydrogen. Reaction intermediates may include
esters, acids, and ketones, alcohols, among others.
[0029] In some embodiments, the hydrotreating stage 12 may include
a hydrotreatment catalyst. Examples of suitable hydrotreatment
catalyst may contain at least one of Group VIB and/or Group VIII
metals, optionally on a support such as alumina or silica. Examples
can include, but are not limited to, NiMo, CoMo, and NiW supported
catalysts. The hydrotreating stage 12 can be operated at any
suitable conditions that are effective for hydrotreatment.
Effective hydrotreatment conditions may include, but are not
limited to, a temperature of about 500.degree. F. (about
260.degree. C.) or higher, for example, about 550.degree. F. (about
288.degree. C.) or higher, about 600.degree. F. (about 316.degree.
C.) or higher, or about 650.degree. F. (about 343.degree. C.) or
higher. Additionally, or alternately, the temperature can be about
750.degree. F. (about 399.degree. C.) or less, for example about
700.degree. F. (about 371.degree. C.) or less, or about 650.degree.
F. (about 343.degree. C.) or less. Effective hydrotreatment
conditions can additionally or alternately include, but are not
limited to, a total pressure of about 400 psig (about 2.8 MPag) or
more, for example, about 500 psig (about 3.4 MPag) or more, about
750 psig (about 5.2 MPag) or more, or about 1000 psig (about 6.9
MPag) or more. Additionally or alternately, the total pressure can
be about 2000 psig (about 10.3 MPag) or less, for example about
1200 psig (about 8.2 MPag) or less, about 1000 psig (about 6.9
MPag) or less, or about 800 psig (about 5.5 MPag) or less. In some
embodiments, the hydrotreating conditions can include, but are not
necessarily limited to, a temperature of about 315.degree. C. to
about 425.degree. C. and a total pressure of about 300 psig (about
2.1 MPag) to about 3000 psig (about 21 MPag).
[0030] While not shown on FIG. 1, a separation device (e.g.,
hydrotreating separator 36 on FIG. 2) can be used to separate out
light streams (e.g., hydrogen) prior to passing the hydrotreated
biofeedstock to the dewaxing stage 18. The separation device can be
a separator, a stripper, a fractionator, or another device suitable
for separating gas-phase products from liquid-phase products. For
instance, a separation device can be used to remove unreacted
hydrogen and/or at least a portion of any H.sub.2S and/or NH.sub.3
formed during hydrotreatment, e.g., with the remainder of the
H.sub.2S and/or NH.sub.3 formed during hydrotreatment being
cascaded to the dewaxing stage 18, as desired. Alternately, the
entire effluent from the hydrotreatment stage 12 can be cascaded to
the dewaxing stage 18, if desired.
[0031] As previously described, the hydrotreatment stage 12 should
at least partially deoxygenate the biofeedstock in the biofeed
stream 14. Deoxygenating the biofeedstock can avoid problems with
catalyst poisoning or deactivation due to the creation of water or
carbon oxides during the subsequent catalytic dewaxing in the
dewaxing stage 18. The hydrotreatment stage 12 can be used to
substantially deoxygenate the biofeedstock. This corresponds to
removing about 90% or more, for example, about 95% or more, about
98% or more, about 99% or more, about 99.5% or more, about 99.9%
or, or completely (measurably) all the oxygen present in the
biofeedstock. Alternately, substantially deoxygenating the
biofeedstock can correspond to reducing the oxygenate level of the
hydrotreated biofeedstock to about 0.1 wt. % or less, for example,
about 0.05 wt. % or less, about 0.03 wt. % or less, about 0.02 wt.
% or less, about 0.01 wt. % or less, about 0.005 wt. % or less,
about 0.003 wt. % or less, about 0.002 wt. % or less, or about
0.001 wt. % or less.
[0032] The system 10 may include the online analyzer 24 to prevent
inadequately deoxygenated biofeedstock from being passed to the
dewaxing stage 18, in accordance with present embodiments. The
online analyzer 24 may be positioned to analyze the hydrotreated
biofeedstock from the hydrotreatment stage 12. The online analyzer
24 may be positioned at any suitable location for monitoring the
hydrotreated biofeedstock. As illustrated, the online analyzer 24
may be positioned between the hydrotreatment stage 12 and the
dewaxing stage 18. In some embodiments, the online analyzer 24 may
be positioned to measure the effluent from a hydrodeoxygenation
reactor (e.g., hydrodeoxygenation reactor 34 on FIG. 2). In some
embodiments, the online analyzer 24 may be positioned to measure
the liquid-phase products from a separation device (e.g.,
hydrogenation separator 36 on FIG. 2) in the hydrotreatment stage
12. The online analyzer 24 may analyze all or a portion of the
hydrotreated products. For example, the online analyzer 24 may
measure a slipstream (not shown) of the hydrotreated product stream
20. Should the measurements from the online analyzer indicate there
has been insufficient conversion, the hydrotreated biofeedstock can
be recycled to the hydrotreating stage 12 for further reaction. If
there is insufficient conversion of the hydrotreated biofeedstock,
the hydrotreated biofeedstock would contain too much oxygen in
either unreacted biofeedstock or intermediates, thus potentially
prematurely deactivating the catalyst in the dewaxing stage 18.
[0033] Examples of suitable analyzers that can be used for the
online analyzer 24 include, but are not limited to, infrared
spectrometers, near infrared spectrometers, and Raman
spectrometers. Infrared spectrometers typically involve interaction
of infrared radiation with matter to produce an infrared spectrum.
The infrared spectrum can be visualized as a graph of light
absorbance (or transmittance) on the vertical (y-axis) versus
frequency (or wavelength) on the horizontal (x-axis). Units of
frequency may be reported in reciprocal centimeters (cm.sup.-1).
Units of wavelength may be reported in micrometers. Near infrared
spectrometers utilize the near infrared region, generally from 780
nm to 2500 nm. Similar to infrared spectrometers, the infrared
spectrums from near infrared spectrometers can also be visualized
as a graph of light absorbance (or transmittance) on the vertical
(y-axis) versus frequency (or wavelength) on the horizontal
(x-axis). In infrared spectra, each peak generally corresponds to a
different functional group, such as C.dbd.O, O--H, among others.
Raman spectrometers utilize a spectroscopic technique that uses
light scattering to determine vibrational modes of molecules and
produce a Raman spectrum. The Raman spectrum can be visualized a
graph showing the intensity and wavelength position of the
scattered light. In Raman spectra, each peak generally corresponds
to different molecular bonds, such as C--C, N--O, C=0, among
others.
[0034] Measurements from the online analyzer 24 may be correlated
with conversion of the biofeedstock. For example, the online
analyzer 24 can measure concentration of certain groups (e.g.,
carbonyl groups (C=0)) in the hydrotreated biofeedstock, which
indicates presence of the biofeedstock or intermediate products.
For example, the peak intensity at the characteristic group peak
may be monitored, thus providing an indication (indirect
measurement) of the oxygen content in the hydrotreated
biofeedstock. The concentration of the carbonyl groups may be
represented in the measurements of the online analyzer 24 by peak
intensity. For example, the carbonyl peak on an infrared spectrum
can be at 1745 (+/-10) cm.sup.-1. This peak at approximately 1745
cm.sup.-1 has been confirmed to be the carbonyl peak in the
biofeedstock (or intermediates) through a secondary analytical
technique, gas chromatograph-mass spectrometry. Because this peak
on the infrared spectrum correlates to the carbonyl peak, this peak
at approximately 1745 cm.sup.-1 can detect trace amounts of the
carbonyl group in the hydrotreated biofeedstock to indicate
insufficient conversion.
[0035] As illustrated, a controller 26 may operate a recycle valve
28 to control recycle of the hydrotreated biofeedstock. For
example, the recycle valve 28 may be used to direct the
hydrotreated biofeedstock through recycle line 30 instead of to the
dewaxing stage 18. The controller 26 may include any suitable
device for processing instructions, including, but not limited to,
a microprocessor, microcontroller, embedded microcontroller,
programmable digital signal processor, or other programmable
device. The controller 26 may also, or instead, be embodied in an
application specific integrated circuit, a programmable gate array,
programmable array logic, or any other device or combinations of
devices operable to process electric signals. The controller 26 can
be configured to receive inputs from the online analyzer 24 and to
send control signals to the recycle valve 28. The controller 26 may
also send control signals to the online analyzer 24. A set
intensity value may be input and/or otherwise stored in the
controller 26. The set intensity value could be a value that if
exceeded would indicate insufficient conversion in that the
measurements of the hydrotreated biofeedstock would include too
much unconverted biofeedstock and intermediates with oxygen. In
some embodiments, the controller 26 may compare the measured
intensity value from the online analyzer 24 at the peak of interest
(e.g., carbonyl peak such as approximately 1745 cm.sup.-1 on an
infrared spectrum) to the set intensity value. If the measured
intensity value exceeds the set intensity value, it would indicate
insufficient conversion with the controller 26 directing the
hydrotreated biofeedstock through the recycle valve 28 back to the
hydrotreating stage 12. However, if the measured intensity value is
equal to or less than the set intensity value, it would indicate
sufficient conversion with the hydrotreated biofeedstock being sent
to the dewaxing stage 18. It should be understood that the above
description is merely an example of one methodology for operation
of the online analyzer 24, for example, with the controller 26.
[0036] In the dewaxing stage 18, at least a portion of the
hydrotreated biofeedstock in the hydrotreated product stream 20 may
be catalytically dewaxed to produce a renewable diesel product
stream 22 with improved its cold flow properties, such as pour
point and/or cloud point. Catalytic dewaxing relates to the removal
and/or isomerization of long chain paraffinic molecules from the
hydrotreated biofeedstock. Catalytic dewaxing may be accomplished
by selective hydrocracking or by hydroisomerization of these long
chain molecules. In addition to renewable diesel product stream 22,
dewaxing gas stream 32 may also exit the dewaxing stage 18. The
dewaxing gas stream 32 may contain hydrogen and other gases
generated in the dewaxing stage 18.
[0037] The dewaxing stage 18 can include a dewaxing catalyst. As
previously described, the dewaxing catalyst can be sensitive to
oxygen so example embodiments include monitoring the hydrotreated
biofeedstock with the online analyzer 24 so that the hydrotreated
biofeedstock can be recycled to the hydrotreating stage 12 if too
much oxygen is present. In some embodiments, the dewaxing catalyst
can include molecular sieves such as crystalline aluminosilicates
(zeolites) and/or silicoaluminophosphates (SAPOs). For example, the
molecular sieve can be a 1-D or 3-D molecular sieve. By way of
further example, the molecular sieve can be a 10-member ring 1-D
molecular sieve (e.g., ZSM-48). Examples of molecular sieves can
include, but are not limited to, ZSM-48, ZSM-23, ZSM-35, Beta, USY,
ZSM-5, and combinations thereof. In an embodiment, the molecular
sieve can include or be ZSM-48, ZSM-23, or a combination thereof.
The dewaxing catalyst can optionally include a binder, such as
alumina, titania, silica, silica-alumina, zirconia, or a
combination thereof. In an embodiment, the binder can include or be
alumina, titania, or a combination thereof. In another embodiment,
the binder can include or be titania, silica, zirconia, or a
combination thereof.
[0038] The dewaxing catalyst can also include a metal hydrogenation
component, such as a Group VIII metal. Suitable Group VIII metals
can include, but are not limited to, Pt, Pd, Ni, and combinations
thereof. The dewaxing catalyst can advantageously include about 0.1
wt. % or more of the Group VIII metal, for example, about 0.3 wt. %
or more, about 0.5 wt. % or more, about 1.0 wt. % or more, about
2.0 wt. % or more, about 2.5 wt. % or more, about 3.0 wt. % or
more, or about 5.0 wt. % or more. Additionally or alternately, the
dewaxing catalyst can include about 10.0 wt. % or less of a Group
VIII metal, for example about 7.0 wt. % or less, about 5.0 wt. % or
less, about 3.0 wt. % or less, about 2.5 wt. % or less, about 2.0
wt. % or less, or about 1.5 wt. % or less.
[0039] In some embodiments, particularly when Group VIII metal is a
non-noble metal such as Ni, the dewaxing catalyst may additionally
include a Group VIB metal, such as W and/or Mo. For instance, in
one embodiment, the dewaxing catalyst can include Ni and W, Ni and
Mo, or a combination of Ni, Mo, and W. In certain such embodiments,
the dewaxing catalyst can include about 0.5 wt. % or more of the
Group VIB metal, for example, about 1.0 wt. % or more, about 2.0
wt. % or more, about 2.5 wt. % or more, about 3.0 wt. % or more,
about 4.0 wt. % or more, or about 5.0 wt. % or more. Additionally
or alternately, the dewaxing catalyst can include about 20.0 wt. %
or less of a Group VIB metal, for example about 15.0 wt. % or less,
about 12.0 wt. % or less, about 10.0 wt. % or less, about 8.0 wt. %
or less, about 5.0 wt. % or less, about 3.0 wt. % or less, or about
1.0 wt. % or less. In one particular embodiment, the dewaxing
catalyst can include only a Group VIII metal selected from Pt, Pd,
and a combination thereof.
[0040] Catalytic dewaxing can be performed by exposing the
hydrotreated biofeedstock to a dewaxing catalyst (that may, and
usually does, also have isomerization activity) under effective
(catalytic) dewaxing (and/or isomerization) conditions. Effective
dewaxing conditions can include, but are not limited to, a
temperature of about 500.degree. F. (about 260.degree. C.) or
higher, for example, bout 550.degree. F. (about 288.degree. C.) or
higher, about 600.degree. F. (about 316.degree. C.) or higher, or
about 650.degree. F. (about 343.degree. C.) or higher.
Additionally, or alternately, the temperature can be about
750.degree. F. (about 399.degree. C.) or less, for example about
700.degree. F. (about 371.degree. C.) or less, or about 650.degree.
F. (about 343.degree. C.) or less. Effective dewaxing conditions
can additionally or alternately include, but are not limited to, a
total pressure of about 200 psig (about 1.4 MPag) or more, for
example, about 250 psig (1.7 Mpag) or more, about 500 psig (about
3.4 MPag) or more, about 750 psig (about 5.2 MPag) or more, or
about 1000 psig (about 6.9 MPag) or more. Additionally or
alternately, the total pressure can be about 1500 psig (about 10.3
MPag) or less, for example about 1200 psig (about 8.2 MPag) or
less, about 1000 psig (about 6.9 MPag) or less, or about 800 psig
(about 5.5 MPag) or less.
[0041] FIG. 2 illustrates an example of the system 10 for renewable
diesel production in accordance with some embodiments. As
illustrated, the system 10 may include the hydrotreating stage 12
and the dewaxing stage 18. The hydrotreating stage 12 may include a
hydrodeoxygenation reactor 34 and a hydrotreating separator 36. The
dewaxing stage 18 may include a dewaxing reactor 38 and a dewaxing
separator 40. The online analyzer 24 may be positioned between the
hydrotreating separator 36 and the dewaxing reactor 38.
[0042] In operation, a biofeedstock stream 14 and a hydrogen stream
16 may be introduced into the hydrotreating stage 16. As
illustrated, the biofeedstock stream 14 and the hydrogen stream 16
can be combined and introduced into the hydrodeoxygenation reactor
34. However, it should be understood that these streams may
alternatively be separately introduced to the hydrodeoxygenation
reactor 34. The hydrotreatment in the hydrodeoxygenation reactor 34
is discussed in the preceding sections. As illustrated, the
hydrodeoxygenation reactor effluent stream 42 may flow from the
hydrodeoxygenation reactor 34 into a hydrogenation separator 36 for
separation of the gas-phase products from the liquid-phase
products. The liquid-phase products may be withdrawn from the
hydrogenation separator 36 as hydrotreated product stream 20. The
gas-phase products may be withdrawn from the hydrogenation
separator 36 as hydrotreated gas recycle stream 46. As illustrated,
the hydrotreated gas recycle stream 46 may be combined with the
dewaxing gas stream 32 from the dewaxing separator 40 to form the
hydrogen stream 16 fed to the hydrodeoxygenation reactor 34. Makeup
hydrogen stream 42 may also be combined into the hydrogen stream 16
as needed.
[0043] The hydrotreated product stream 20 can be introduced into
the dewaxing stage 18. As illustrated, the hydrotreated product
stream 20 may be introduced into dewaxing reactor 38. The dewaxing
that occurs in the dewaxing reactor 38 is discussed in the
preceding sections. The dewaxing reactor effluent 44 may be
introduced into a dewaxing separator 40 for separation of the
gas-phase products from the liquid-phase products. The gas-phase
products may be withdrawn from the dewaxing separator 40 as
dewaxing gas stream 32 and combined with the hydrotreated gas
recycle stream 46 for recycle to the hydrodeoxygenation reactor 34.
The liquid-phase products may be withdrawn from the dewaxing
separator 40 as renewable diesel product 22.
[0044] Accordingly, the preceding description describes utilization
of an online analyzer to monitor conversion of the biofeedstock in
a first hydrotreating stage to avoid catalyst poisoning in a
subsequent stage. The apparatus, systems, and methods disclosed
herein may include any of the various features disclosed herein,
including one or more of the following embodiments.
[0045] Embodiment 1. A method of processing a biofeedstock,
comprising: hydrotreating the biofeedstock by reaction with
hydrogen to form a hydrotreated biofeedstock; and monitoring
conversion of the biofeedstock in the hydrotreating with an online
analyzer.
[0046] Embodiment 2. The method of embodiment 1, wherein the
biofeedstock comprises at one component selected from the group
consisting of a vegetable oil, an animal fat, a fish oil, a
pyrolysis oil, algae lipid, an algae oil, and combinations
thereof.
[0047] Embodiment 3. The method of embodiment 1 or 2, wherein the
biofeedstock comprises lipid compounds.
[0048] Embodiment 4. The method of any preceding embodiment,
wherein the hydrotreated biofeedstock comprises paraffin
products.
[0049] Embodiment 5. The method of any preceding embodiment,
wherein the online analyzer comprises a spectrometer.
[0050] Embodiment 6. The method of any preceding embodiment,
wherein the online analyzer is an infrared spectrometer, a near
infrared spectrometer, or a Raman spectrometer.
[0051] Embodiment 7. The method of any preceding embodiment,
wherein the monitoring conversion of the biofeedstock comprises
determining oxygen removal from the biofeedstock.
[0052] Embodiment 8. The method of any preceding embodiment,
wherein the monitoring conversion comprises correlating
measurements from the online analyzer with conversion of the
biofeedstock.
[0053] Embodiment 9. The method of any preceding embodiment,
wherein the monitoring conversion comprises measuring carbonyl
group concentration in the hydrotreated biofeedstock.
[0054] Embodiment 10. The method of any preceding embodiment,
wherein the online analyzer is positioned between a
hydrodeoxygenation reactor and a dewaxing reactor.
[0055] Embodiment 11. The method of any preceding embodiment,
further comprising contacting at least a portion of the
hydrotreated biofeedstock with a dewaxing catalyst to produce a
renewable diesel product.
[0056] Embodiment 12. The method of claim 11, further comprising
separating gas-phase products from the hydrotreated biofeedstock
before the contacting at least the portion of the hydrotreated
biofeedstock.
[0057] Embodiment 13. The method of any preceding embodiment,
further comprising recycling the hydrotreated biofeedstock to the
hydrotreating until the monitoring conversion indicates that about
90 wt. % or more of oxygen is removed from the biofeedstock.
[0058] Embodiment 14. The method of any preceding embodiment,
further comprising recycling the hydrotreated biofeedstock to the
hydrotreating until the monitoring conversion indicates that about
99 wt. % or more of oxygen is removed from the biofeedstock.
[0059] Embodiment 15. The method of any preceding embodiment,
further comprising recycling the hydrotreated biofeedstock until a
peak intensity for a carbonyl peak on an infrared spectrum from the
online analyzer is below a set intensity value.
[0060] Embodiment 16. A system for production of renewable diesel
comprising: a hydrotreatment stage comprising a hydrodeoxygenation
reactor that receives a biofeedstock; a dewaxing stage comprising a
dewaxing reactor that receives a hydrotreated product stream from
the hydrotreatment stage; and an online analyzer positioned to
analyze the hydrotreated product stream to monitor conversion of
the biofeedstock in the hydrotreatment stage.
[0061] Embodiment 17. The system of embodiment 16, wherein the
online analyzer is an infrared spectrometer, a near infrared
spectrometer, or a Raman spectrometer.
[0062] Embodiment 18. The system of embodiment 16 or 17, further
comprising a controller that controls recycles of the hydrotreated
product stream in response to measurements from the online
analyzer.
[0063] Embodiment 19. The system of claim 18, further comprising a
recycle valve, wherein the controller is configured to send control
signals to the recycle valve in response to the measurements from
the online analyzer.
[0064] Embodiment 20. The system of any one of claims 16 to 19,
wherein the online analyzer is positioned between the
hydrodeoxygenation reactor and the dewaxing reactor.
[0065] To facilitate a better understanding of the embodiments
described herein, the following examples of certain aspects of some
embodiments are given. In no way should the following examples be
read to limit, or define, the scope of the present disclosure.
Examples
[0066] To illustrate the use of an online analyzer in monitoring
conversion of a biofeedstock in a hydrotreatment the following
example was performed. The biofeedstock used in this example was
canola oil. The canola oil was reacted with hydrogen over a
hydrotreatment catalyst at conditions effective to produce
hydrotreatment products, such as paraffin products. The reaction
products were then tested periodically at various stages of
reaction to evaluate conversion. The reaction products were tested
with an infrared spectrometer and also with a gas chromatograph
mass spectrometer (GCMS).
[0067] FIG. 3 shows the infrared spectrum of the biofeedstock
(canola oil) used in this example. The characteristic carbonyl
group of the canola oil is show at approximately 1745 cm.sup.-1.
Canola oil contains oxygen in an amount of about 10.9 wt. %.
[0068] FIG. 4 shows the infrared spectrum of an early-stage product
of the hydrotreatment of the canola oil. At this early stage, the
oxygen content was reduced from 10.9 wt. % to 6.6 wt. %. Since the
early-stage product still contained a significant amount of oxygen,
the infrared spectrum still showed a significant peak at
approximately 1745 cm.sup.-1. The GCMS data shown in FIG. 5 for the
early-stage product confirms the existence of canola oil as well as
esters, acids, and ketones in the early-stage product.
[0069] FIG. 6 shows the infrared spectrum of a middle-stage product
of the hydrotreatment of the canola oil. At this middle stage, the
oxygen content was further reduced to 5.8 wt. %. Since the oxygen
content was reduced as compared to FIG. 3 for canola oil and FIG. 4
for the early-stage product, the peak at approximately 1745
cm.sup.-1 was reduced. The GCMS data shown in FIG. 7 for the
middle-stage product shows that the canola oil was reduced as
compared to the GCMS data in FIG. 5 for the early-stage
product.
[0070] FIG. 8 shows the infrared spectrum of a late-stage product
of the hydrotreatment of the canola oil. At this late stage, the
oxygen content was reduced to 0.34 wt. %. Since the oxygen content
of the late-stage product was only 0.34 wt. %, the peak at
approximately 1745 cm.sup.-1 was very weak. The GCMS data shown in
FIG. 9 for the late-stage product shows that the canola oil was
fully converted, and only small amounts of esters and ketones were
present in the late-stage product.
[0071] FIG. 10 shows the infrared spectrum of a fully converted
product of the hydrotreatment of the canola oil. At this stage, the
oxygen content was reduced to less than 0.1 wt. %. Since the oxygen
content in the product was below the detection limit, the peak at
approximately 1745 cm.sup.-1 was no longer detectable. The GCMS
data shown in FIG. 11 for this product shows that the canola oil
was fully converted. Intermediate products such as esters and
ketones were further reduced in the product as compared to the GCMS
data for other stage products.
[0072] While the invention has been described with respect to a
number of embodiments and examples, those skilled in the art,
having benefit of this disclosure, will appreciate that other
embodiments can be devised which do not depart from the scope and
spirit of the invention as disclosed herein. Although individual
embodiments are discussed, the invention covers all combinations of
all those embodiments.
[0073] While compositions, methods, and processes are described
herein in terms of "comprising," "containing," "having," or
"including" various components or steps, the compositions and
methods can also "consist essentially of" or "consist of" the
various components and steps. The phrases, unless otherwise
specified, "consists essentially of" and "consisting essentially
of" do not exclude the presence of other steps, elements, or
materials, whether or not, specifically mentioned in this
specification, so long as such steps, elements, or materials, do
not affect the basic and novel characteristics of the invention,
additionally, they do not exclude impurities and variances normally
associated with the elements and materials used.
[0074] The phrase "major amount" or "major component" as it relates
to components included within the renewable diesel of the
specification and the claims means greater than or equal to 50 wt.
%, or greater than or equal to 60 wt. %, or greater than or equal
to 70 wt. %, or greater than or equal to 80 wt. %, or greater than
or equal to 90 wt. % based on the total weight of the thermal
management fluid. The phrase "minor amount" or "minor component" as
it relates to components included within the renewable diesel of
the specification and the claims means less than 50 wt. %, or less
than or equal to 40 wt. %, or less than or equal to 30 wt. %, or
greater than or equal to 20 wt. %, or less than or equal to 10 wt.
%, or less than or equal to 5 wt. %, or less than or equal to 2 wt.
%, or less than or equal to 1 wt. %, based on the total weight of
the thermal management fluid. The phrase "substantially free" or
"essentially free" as it relates to components included within the
renewable diesel of the specification and the claims means that the
particular component is at 0 weight % within the renewable diesel,
or alternatively is at impurity type levels within the renewable
diesel (less than 100 ppm, or less than 20 ppm, or less than 10
ppm, or less than 1 ppm).
[0075] All numerical values within the detailed description and the
claims herein modified by "about" or "approximately" with respect
the indicated value are intended to take into account experimental
error and variations that would be expected by a person having
ordinary skill in the art.
[0076] For the sake of brevity, only certain ranges are explicitly
disclosed herein. However, ranges from any lower limit may be
combined with any upper limit to recite a range not explicitly
recited, as well as, ranges from any lower limit may be combined
with any other lower limit to recite a range not explicitly
recited, in the same way, ranges from any upper limit may be
combined with any other upper limit to recite a range not
explicitly recited.
* * * * *