U.S. patent application number 15/254453 was filed with the patent office on 2016-12-22 for solvent extraction process to stabilize, desulphurize and dry wide range diesels, stabilized wide range diesels obtained and their uses.
The applicant listed for this patent is ENVIROLLEA INC.. Invention is credited to Lucie B. WHEELER.
Application Number | 20160369175 15/254453 |
Document ID | / |
Family ID | 44541587 |
Filed Date | 2016-12-22 |
United States Patent
Application |
20160369175 |
Kind Code |
A1 |
WHEELER; Lucie B. |
December 22, 2016 |
SOLVENT EXTRACTION PROCESS TO STABILIZE, DESULPHURIZE AND DRY WIDE
RANGE DIESELS, STABILIZED WIDE RANGE DIESELS OBTAINED AND THEIR
USES
Abstract
A process allowing the removal of contaminants from an unstable
oil such as those produced by thermal or catalytic cracking,
wherein, in at least one step of the process, mixing of the
unstable oil with a pure or impure solvent having a dipole moment
greater than 2 is performed. The stabilized diesels thereby
obtained exhibit interesting properties among which significant
stability features and are useful in numerous applications, some of
these stabilized wide range diesels are new as well as their
uses.
Inventors: |
WHEELER; Lucie B.; (Calgary,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ENVIROLLEA INC. |
Calgary |
|
CA |
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|
Family ID: |
44541587 |
Appl. No.: |
15/254453 |
Filed: |
September 1, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14644628 |
Mar 11, 2015 |
9458391 |
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15254453 |
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13591772 |
Aug 22, 2012 |
8999147 |
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14644628 |
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PCT/CA2011/050117 |
Feb 28, 2011 |
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13591772 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 2300/1055 20130101;
C10G 2300/30 20130101; C10G 2300/202 20130101; C09K 8/34 20130101;
C10G 2400/04 20130101; C10G 2300/301 20130101; C10G 55/06 20130101;
C10L 10/12 20130101; C10G 2400/10 20130101; C10G 21/22 20130101;
C10G 21/12 20130101; C10G 21/27 20130101; C10G 2300/1007 20130101;
C10L 1/08 20130101; C10G 21/20 20130101; C10G 55/04 20130101; C10G
2300/4081 20130101; C10G 2300/201 20130101; C10L 2270/026 20130101;
C10L 2200/0446 20130101; B01D 11/0434 20130101; C10G 2300/1077
20130101; C10G 21/16 20130101; C10L 2290/544 20130101; C10G 21/28
20130101; C10G 2300/4006 20130101; C10G 2300/4012 20130101; C10G
2300/44 20130101; C10G 21/06 20130101; C10G 2300/80 20130101 |
International
Class: |
C10G 21/28 20060101
C10G021/28; C09K 8/34 20060101 C09K008/34; C10L 1/08 20060101
C10L001/08; C10L 10/12 20060101 C10L010/12; C10G 21/16 20060101
C10G021/16; C10G 21/20 20060101 C10G021/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2010 |
CA |
2694821 |
Mar 1, 2010 |
CA |
2694850 |
Mar 1, 2010 |
CA |
2694853 |
Claims
1. A process to stabilize and to remove contaminants from unstable
oil and to produce a stabilized diesel showing, according to ASTM
method D46468 for at least one day, said process comprising the
following steps of: a) intimately contacting a stream of the
unstable oil with an initial solvent having a dipole moment greater
than 2, to obtain two mixtures, a first mixture being of an
oil-solvent type, which comprises treated oil, solvent, and
impurities, and a second mixture being of a solvent-oil type, which
comprises treated oil, solvent, residues, and impurities; b)
separating the treated oil, present in the first mixture obtained
in step a), from the solvent leaving most of the impurities in the
solvent phase; c) separating the solvent and the treated oil,
present in the second mixture obtained in step a) from the
residues; and d) recycling, in the process, one or more solvents
with impurities, recovered in step b) or c) and partially
regenerated before being recycled to said process; wherein in step
b) at least 70% wt of the impurities remain in the solvent phase;
wherein in step d), at least one of each solvent is regenerated,
for at least 50% wt, but for less or equal to 98% wt to obtain a
regenerated solvent stream, before recycling, optionally, wherein
the treated oil recovered from the first mixture is mixed with the
treated oil recovered from the second mixture.
2. The process of claim 1, wherein the stabilized diesel is stable
for at least a day.
3. The process of claim 1, wherein the stabilized diesel is stable
for at least a week, and most preferably for about 6 months.
4. The process of claim 1, wherein the stabilized diesel has a
sulphur content that is, according to Iso 8754, less than 0.2%
wt.
5. The process of claim 1, wherein the stabilized diesel has a
sulphur content that is, less than 0.1% weight and more preferably
is about 0.08% weight.
6. The process of claim 1, wherein the stabilized diesel has a
boiling temperature, according to ASTM D-86, that ranges from
150.degree. C. to 500.degree. C. and preferably ranges from
175.degree. C. to 450.degree. C.
7. The process of claim 1, wherein the stabilized diesel has an
abnormal peak in the ASTM D-86 curb in the area of the peak of the
recycled solvent that has passed at least once through the
process.
8. The process of claim 1, wherein the stabilized diesel has an
abnormal peak in the ASTM D-86 curb in the area of 0 to 10% of
distilled volume, preferably in the area of 5% of distilled
volume.
9. The process of claim 1, wherein the stabilized diesel shows:
according to ASTM method D6468, a stability for at least a day;
according to ASTM method D1500, a colour index that is lower than
3; and an abnormal peak, in the ASTM D-86 curb, in the area of 0 to
10% of distilled volume.
10. The process of claim 9, wherein the stabilized diesel has a
boiling temperatures range according to ASTM D-86, comprised
between 150.degree. C. and 450.degree. C.
11. A process to stabilize and to remove contaminants from unstable
oil and to produce a stabilized diesel having an abnormal peak in
the ASTM-D-86 curb in the area of the peak of the recycled solvent
that has passed at least once through the process, said process
comprising the following steps of: a) intimately contacting a
stream of the unstable oil with an initial solvent having a dipole
moment greater than 2, to obtain two mixtures, a first mixture
being of an oil-solvent type, which comprises treated oil, solvent,
and impurities, and a second mixture being of a solvent-oil type,
which comprises treated oil, solvent, residues, and impurities; b)
separating the treated oil, present in the first mixture obtained
in step a), from the solvent leaving most of the impurities in the
solvent phase; c) separating the solvent and the treated oil,
present in the second mixture obtained in step a) from the
residues; and d) recycling, in the process, one or more solvents
with impurities, recovered in step b) or c) and partially
regenerated before being recycled to said process; wherein in step
b) at least 70% wt of the impurities remain in the solvent phase;
wherein in step d), at least one of each solvent is regenerated,
for at least 50% wt, but for less or equal to 98% wt to obtain a
regenerated solvent stream, before recycling, optionally, wherein
the treated oil recovered from the first mixture is mixed with the
treated oil recovered from the second mixture.
12. The process of claim 11, wherein the stabilized diesel is
stable for at least a day.
13. The process of claim 11, wherein the stabilized diesel is
stable for at least a week, and most preferably for about 6
months.
14. The process of claim 11, wherein the stabilized diesel has a
sulphur content that is, according to Iso 8754, less than 0.2%
wt.
15. The process of claim 11, wherein the stabilized diesel has a
sulphur content that is, less than 0.1% weight and more preferably
is about 0.08% weight.
16. The process of claim 11, wherein the stabilized diesel has a
boiling temperature, according to ASTM D-86, that ranges from
150.degree. C. to 500.degree. C. and preferably ranges from
175.degree. C. to 450.degree. C.
17. The process of claim 11, wherein the stabilized diesel has a
boiling temperature, according to ASTM D-86, that ranges from
175.degree. C. to 450.degree. C.
18. The process of claim 11, wherein the stabilized diesel has an
abnormal peak in the ASTM D-86 curb in the area of 0 to 10% of
distilled volume, preferably in the area of 5% of distilled
volume.
19. The process of claim 11, wherein the stabilized diesel shows:
according to ASTM method D6468, a stability for at least a day;
according to ASTM method D1500, a colour index that is lower than
3; and an abnormal peak, in the ASTM D-86 curb, in the area of 0 to
10% of distilled volume.
20. The process of claim 19, wherein the stabilized diesel has a
boiling temperatures range according to ASTM D-86, comprised
between 150.degree. C. and 450.degree. C.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/644,628 filed on 11 Mar. 2015, that is a
continuation of U.S. patent application Ser. No. 13/591,772 filed
on 22 Aug. 2012 now U.S. Pat. No. 8,999,147, that is a continuation
of PCT patent application No. PCT/CA2011/050117 filed on 28 Feb.
2011, which claims priority to Canadian patent application Nos.
2,694,821, 2,694,850 and 2,694,853 filed on 1 Mar. 2010. The
content of all these applications is hereby incorporated by
reference.
TECHNICAL FIELD
[0002] The invention relates to an extraction process using a
polarized solvent having a dipole moment greater than 2, to
stabilize wide range diesels, containing or not free radicals, such
as those produced by the thermal or catalytic cracking of used
oils, heavy oils, vacuum gasoils or bunkers. The new process
markedly improves colour, odour and storage stability of thermally
cracked gasoils so they can meet market specifications. The
extraction process also removes water, sulphurous compounds and
chlorides when present from the wide range diesels, reduces their
total acid number and increases their cetane index.
[0003] The invention also relates to a new family of wide range
diesels, including those wide range diesels obtained by the
processes of the invention, as well as to numerous uses of the wide
range diesels of the invention, and more particularly to lucrative
uses and/or to some applications beneficial to the environment.
BACKGROUND
[0004] Gasoils or diesels produced from thermal or catalytic
cracking processes are known to be unstable. While in storage, they
form gums and polymers that can plug burner tips in furnaces or
filters in engines. Further, new environmental constraints demand
that these fuels reduce their sulphur, nitrogen, water and
chlorides contents. Hydrotreating is commonly used in refineries to
stabilize gasoils and to remove some of their contaminants.
However, hydrotreating processes require high pressures and/or
temperatures and the reactors must either be made of, or clad with,
high alloy steels to resist hydrogen permeation in the metal walls.
There must also be a hydrogen plant or pipeline close by. Because
of the high costs of such units, they are only viable as part of
refineries or large plants. Also, the hydrotreated oils must be
dried to meet water content and appearance specifications.
[0005] Used lubricating oils are classified as hazardous products
in many countries, mostly because of the additives that they
contain. Of all the by-products from the oil industry, used oils
pose the greatest danger to the fresh water supply. The
Environmental Protection Agency (EPA) states that: "One gallon of
used oil can pollute one million gallons of water". Among the
processes to treat used oils for their reuse as fuel, thermal
cracking is a viable option for smaller facilities. More precisely,
the additives in the used oil must be destroyed and removed. The
main product is a wide range diesel or heating fuel. It tends to
darken as soon as it comes into contact with air: it is unstable.
Also, the wide range diesel has a high sulphur content, 3 or 4
times the 0.1% wt sulphur specification for heating oils in Europe,
and has a bad odour.
[0006] Processes to stabilize and/or desulphurize diesel fuels
produced by cracking heavier oils are well known. In refineries,
hydrocracking and hydrotreating processes use hydrogen in catalytic
reactors at high temperatures and pressures to achieve clear,
stable diesel fuels with good burning characteristics and with
sulphur contents as low as 15 ppm that meet ultra-low sulphur
specifications. These processes not only require large, heavy
reactors made of metals that resist hydrogen permeation, and
corrosion, but also require hydrogen production plants or pipelines
near-by. They are not suited for small or isolated refineries or
used oil applications.
[0007] In used oil applications, the UOP Hylube process (U.S. Pat.
No. 5,904,838) uses hydrogen at high temperatures and pressures to
recycle the feed oil into lubricating oils. Others hydrotreat only
the lube oil products, obtained by successive distillations of used
oils.
[0008] Canadian Patent No. 2,245,025 (Ikura et al.) mentions that
gasoil produced by thermal cracking of used oils can be stabilized
using methanol extraction.
[0009] There are also processes to remove sulphur and/or water from
naphtha and other light oils but these are not applicable to diesel
fuels. In the solutizer process, Canadian Patents Nos. 456,448
(Border) and 456,599 (Bell et al.) mention that mercaptans and
other weak acids contained in sour hydrocarbon distillates, and
more particularly in gasoline distillates, would be extracted with
solutizer solution, i.e. aqueous solutions of alkali metal
hydroxides containing solutizers.
[0010] Hassan et al. (Journal of Applied Sciences Research, 5(5);
pp. 515-521, 2009) mention that sulphur could be removed from
straight run diesel fuel with a mixture of NMP (normal methyl
pyridine), ethylene glycol, DMF (dimethyl formamide) and
furfural.
[0011] Toteva, Topalova, and Manolova (Journal of the University of
Chemical Technology and Metallurgy, 42, I, 2007, pp.17-20) mention
that two-stage extraction of diesel fuel with DMF could reduce the
aromatics and sulphur (from 2% wt to 0.33% wt) in a
non-hydrotreated diesel fuel. This is not enough to meet heating
fuel specifications for sulphur of less than 0.1% wt.
[0012] U.S. Pat. No. 6,320,090 (Sherman et al.) mentions that DMF
could be used as a solvent to remove mostly poly aromatic
hydrocarbons (PAH) as well as sulphur and nitrogen compounds from
used oils that have been subjected to successive vacuum
distillations.
[0013] Others have tried solvent extraction processes to remove
sulphur compounds from fuel oils.
[0014] U.S. Pat. No. 5,753,102 (Funakoshi et al.) uses a mixture of
acetone, water and iodine as the preferred solvent to remove
sulphur from various straight run oils. They also tested more
polarized solvents including DMF, acetonitrile, trimethyl
phosphate, nitromethane, methanol, hexamethyl phosphoramide, acetic
acid, pyridine, and N-methylperolidinone with less success.
[0015] U.S. Pat. No. 5,494,572 (Horii et al.) completes the sulphur
removal from oil that has been hydrotreated using organic solvent
containing nitrogen, specifically pyridinium salts, with another
solvent containing hydroxyl groups, specifically one or more of
water, methanol, ethanol, propanol, butanol, ethylene glycol, and
glycerol. Hydrotreating is the more costly process.
[0016] In the process described by U.S. Pat. No. 5,059,303 (Taylor
et al.), oils produced via cracking processes, ranging from cracked
naphtha, gasoil and vacuum residue, are contacted with an
extraction solvent to reduce their sulphur and nitrogen content
prior to hydrotreating. The solvents used are polarized and in an
aqueous solution. They include N-methyl pyrrolidone, furfural, DMF,
and phenol.
[0017] U.S. Pat. No. 4,405,448 (Googin et al.) mention a polar
solvent, specifically DMF and water, intended to remove
polychlorinated biphenyls (PCB) from transformer oil. A second
extraction using a non-polar solvent, chosen from normal pentane to
normal octane, is intended to remove the PCB from the polar
solvent.
[0018] For the past ten years, several oil desulphurization
processes use an oxidizing agent and a catalyst to oxidize
mercaptans and thiols in the oil. In a second step, polarized
solvents are used to extract the sulphur oxides from the oil.
[0019] U.S. Pat. No. 6,274,785 (Gore) uses dimethylsulfoxide as the
extraction solvent.
[0020] Canadian Patent No. 1,287,007 (Kittrel et al.) suggests
using solvents having a dipole moment greater than 2, mixed with
water, to extract the sulphur and nitrogen oxides from the oil.
[0021] U.S. Pat. No. 5,154,817 (Reid) mentions that cracked oils
can be stabilized with additive injection. However, additives do
not remove mercaptans and thiols from the oil.
[0022] The complete solvent regeneration is difficult because the
solvents and the oils to treat have similar boiling points and
gravities. Solvent losses render these processes impractical.
[0023] There was therefore a need for a new process able to
stabilize, desulphurize, neutralize and dry wide range diesel,
which process being free of at least one of the drawbacks of the
prior processes.
[0024] There was therefore also a need for a process able to
stabilize, desulphurize, neutralize and dry the heating oil to meet
the heating oil specifications, which process being free of at
least one of the drawbacks of the prior processes.
[0025] There was a further need for a process that would also be
effective in reducing the sulphur in diesel cuts produced by
catalytic or thermal cracking of heavy oils in refineries.
[0026] There was particularly a need for a low cost process to
stabilize and remove contaminants from wide range diesels or
gasoils that can be used in smaller plants, such as used oil
cracking units.
[0027] There was a further need for new stabilized wide range
diesel obtained from an unstable oil.
[0028] There was also a need for uses of a stabilized and/or
desulphurized wide range of diesel.
SUMMARY
[0029] A first object of the present invention is the process to
stabilize and to remove contaminants from an unstable oil, the
process comprising at least one step of mixing the unstable oil
with an impure solvent having a dipole moment greater than 2.
[0030] According to a preferred embodiment, the processes allow to
stabilize and to remove contaminants from an unstable oil, wherein
the unstable oil is selected among the family of: mixtures made for
at least 50% wt of hydrocarbons which may include free radicals,
oils produced by thermal cracking, oils obtained by catalytic
cracking, oils obtained by decomposition, oils obtained by
degradation, and the mixtures of at least two of the latter
oils.
[0031] Advantageously, in order to stabilize and to remove
contaminants from an unstable oil, the process includes at least
one step of contacting a stream of the unstable oil with a solvent
having a dipole moment greater than 2 and, thus, obtaining two
mixtures, the first mixture being of an oil-solvent type and
containing impurities, and the second mixture being of a
solvent-oil type and containing residues and impurities, the
impurities in the solvent-oil mixture being identical to, or
different from, the impurities in the oil-solvent mixture.
[0032] According to another preferred embodiment of the invention,
in the processes at least a fraction of the solvent having a dipole
moment greater than 2 that is present in at least one of the two
mixtures is extracted from the mixture(s) and is at least partially
regenerated before being recycled to the process.
[0033] According to a further preferred embodiment of the
invention, the processes comprise the following steps of: [0034] a)
intimately contacting a stream of the unstable oil with a solvent
having a dipole moment greater than 2 and, thus, obtaining two
mixtures, the first mixture being of an oil-solvent type and
containing impurities, and the second mixture being of a
solvent-oil type and containing residues and impurities, the
impurities in the solvent-oil mixture being identical or different
from the impurities in the oil-solvent mixture; [0035] b)
separating the treated oil, present in the oil-solvent mixture
obtained in step a), from the solvent, leaving most of the
impurities in the solvent phase; [0036] c) separating the solvent
and the oil, present in the solvent-oil mixture obtained in step
a), from the residues, leaving preferably at least 90% wt of the
contaminants in the residues; [0037] d) optionally separating the
solvent and the light oil present in the oil-solvent mixture
obtained in step b); [0038] e) optionally separating the solvent
and the oil obtained in step c); and [0039] f) recycling at least
one of the solvents obtained in steps b), c), d) or e), wherein
each of the solvent is at least partially regenerated.
[0040] The processes of the invention are particularly suited to
stabilize and to remove contaminants from an unstable oil, wherein,
in step b), at least 80% wt, preferably at least 90% wt, of the
impurities remain in the solvent phase.
[0041] Advantageously, in step f), at least one of each of the
solvent is regenerated for at least 50% wt but for less or equal to
99% wt, and preferably for at least 55% wt but for less or equal to
98% wt, before recycling.
[0042] Preferably, in step f), at least one of each of the solvent
is regenerated by physical means such as distillation, vacuum
distillation, including thin film or wiped film evaporation,
azeotropic distillation, and or centrifuging.
[0043] Advantageously, in step f), at least one of each of the
solvent is regenerated by using vacuum distillation and/or
centrifuging.
[0044] The processes of the invention are of a particular interest
wherein the boiling range of the unstable oil, as measured by the
method ASTM D86, ranges from 125.degree. C. to 500.degree. C. and
preferably when the boiling range ranges from 175.degree. C. to
450.degree. C.
[0045] Advantageously, the boiling range of the treated oil in step
a), as measured by the method ASTM D86, ranges from 125.degree. C.
to 500.degree. C. and more preferably ranges from 175.degree. C. to
450.degree. C.
[0046] The processes of the invention are of a particular interest
when applied to unstable oils produced by cracking used oil, heavy
oil, bitumen, vacuum gasoil, vacuum residue, tar, synthetic crude
oil, bunker or is produced by cracking a mixture of at least two of
these solvents.
[0047] Advantageous results are obtained when the initial solvent
is chosen among N-methyl pyrrolidone, furfural, dimethyl formamide,
phenol, pyridine, dimethyl acetamide, dimethyl sulfoxide and
propylene carbonate, and among mixtures of at least 2 of these.
[0048] According to a further embodiment of the invention, the
process, to stabilize and to remove contaminants from an unstable
oil, wherein the regenerated solvent, obtained in steps b), c), d)
and/or f), still contains some impurities or reaction products.
[0049] The processes of the invention are of a particular interest,
when the contaminants present in the treated or untreated unstable
oil include: water, sulphur compounds such as mercaptans and
thiols, organic chlorides, organic and inorganic acids, free
radicals, resins, gums, sediments, reaction products and mixtures
of at least two of these.
[0050] The solvent concentration in the regenerated solvent stream
obtained, in step f), advantageously ranges from 50% wt to 99%
wt.
[0051] Advantageously, the solvent concentration in the regenerated
solvent stream obtained, in step f), ranges from 70% wt to 90% wt
and is more preferably about 83% wt.
[0052] According to a preferred embodiment of the invention, the
regenerated solvent is produced, in step f), by a physical process
such as distillation and/or centrifugation. The distillation is
thus advantageously performed at pressures ranging from 0.5 psia to
15 psia, advantageously from 0.55 psia to 12 psia, preferably the
distillation pressures ranging from 0.6 psia to 12 psia,
advantageously from 0.7 psia to 4 psia and more preferably the
distillation is performed at pressures about 1.5 psia.
[0053] Advantageously, the regenerated solvent is produced, in
steps b), c), d), and f), by distillation conducted at temperatures
ranging from 50.degree. C. to 350.degree. C., more preferably
distillations are thus conducted at temperatures ranging from
100.degree. C. to 175.degree. C., and more preferably at a
temperature of about 130.degree. C.
[0054] The processes of the invention are of a particular interest
when the impurities, present in the regenerated and/or recycled
solvent, have a boiling temperature ranging from 120.degree. C. to
250.degree. C., and more preferably in the case wherein the
impurities, present in the regenerated and/or recycled solvent,
have a boiling temperature ranging from 130.degree. C. to
200.degree. C.
[0055] The processes are very efficient when the impurities,
present in the regenerated and/or recycled solvent, have catalytic
and/or solution enhancing and/or bridging properties.
[0056] The processes are very efficient when in step a) the solvent
extraction is carried out at temperatures not exceeding the
decomposition temperature of the solvent. In the case of DMF, the
temperature is advantageously 10% above the boiling point of the
solvent and not exceeding 400.degree. C. Preferably, in the
particular case of DMF, the solvent extraction is carried out at
temperatures ranging from 8.degree. C. to 175.degree. C., more
preferably at temperatures ranging from 15.degree. C. to
155.degree. C., advantageously from 15.degree. C. to 150.degree.
C., more advantageously at temperatures ranging from 10.degree. C.
to 40.degree. C., and more preferably at a temperature of about
25.degree. C.
[0057] Advantageously, the solvent extraction in step b) is carried
out as soon as possible after the unstable oil is produced,
preferably after less than 1 day, and more preferably after less
than 5 minutes after the cracked oil is produced.
[0058] According to a preferred embodiment, the initial solvent to
oil volume ratio ranges from between 5/1 and 1/5, preferably this
ratio is between 2/1 and 1/2; more preferably about 1/1.
[0059] Advantageously, step a) of the processes is performed in a
continuously stirred extraction column.
[0060] Advantageously, step b) of the processes is performed by
using at least one of the following separation techniques such as:
in a thin film evaporator, in a wiped film evaporator, azeotropic
distillation and/or in a centrifuge or by combination of at least
two of these methods.
[0061] According to another preferred embodiment of the process of
the invention to stabilize and remove contaminants, step c) of the
processes is advantageously performed by physical separation such
as settling, vacuum flashing, distillation in a thin film
evaporator, in a wiped film evaporator, azeotropic distillation,
and/or in other separation equipment such as a centrifuge or by
combination of at least two of these methods.
[0062] Advantageously, step d) of the processes is performed by
phase accumulation, or in a wiped film evaporator or in a
centrifuge or by combination of at least two of these methods.
[0063] The processes of the invention are of a particular interest
for treating contaminated wide range diesel fuel, the initial
solvent is thus advantageously a nearly pure solvent having a
dipole moment greater than 2.
[0064] The stable operation of the processing unit, wherein the
operating conditions remain unchanged, may be reached, depending
upon the size of the unit and/or upon the type of the unit and/or
upon the solvent, in between 5 and 120 minutes, and preferably in
about 45 minutes.
[0065] The processes of the invention are also of a particular
interest for treating thermally cracked oils or thermally cracked
used oil, and the initial solvent, having a dipole moment greater
than 2, is thus advantageously DMF.
[0066] In the processes of the invention, the initial temperature
in step a) is between 15.degree. C. and 110.degree. C., preferably
between 20.degree. C. and 30.degree. C., and the initial
temperatures in steps b), c) and d) are between 10.degree. C. and
175.degree. C. and more preferably is about 25.degree. C.
[0067] In the processes of the invention, the initial pressures in
steps b), c) and d) are between 0.5 psia and atmospheric
pressure.
[0068] According to a preferred embodiment, the temperatures in the
various steps of the processes are determined by the vacuum
distillation obtained, but kept below the thermal decomposition
temperature of the solvent and/or the cracking or polymerization
initiation temperatures of the oil.
[0069] Advantageously, the equilibrium temperature in step a) is
between 15.degree. C. and 100.degree. C., and most preferably about
25.degree. C.
[0070] The solvent content in the recycled solvent stream is
preferably between 50% wt and 99% wt, more preferably between 60%
wt and 95% wt, and most advantageously about 83% wt.
[0071] According to further preferred embodiments of the invention:
[0072] the temperatures in steps b), c) and d) are between
10.degree. C. and 175.degree. C.; and/or [0073] the pressures in
steps b), c) and d) are between 0.5 psia and atmospheric pressure;
and/or [0074] the residual water content in the stabilized diesel
obtained is less than 1% wt, preferably less than 0.25% wt; and/or
[0075] the residual water content in the stabilized diesel,
obtained in step a), is less than 1% wt, preferably less than 0.25%
wt.
[0076] A second object of the present invention is constituted by
the family of the stabilized diesels obtained by any one of the
processes defined in the first object of the present invention.
[0077] These stabilized diesels are, according to ASTM method
D6468, stable for at least a day, advantageously for at least a
week, or until it is used, and most preferably they are stable for
about 6 months or more.
[0078] Among the stabilized diesels obtained by the processes of
the invention, these having at least one of the following
properties: [0079] a sulphur content, according to ISO 8754, that
is less than 0.2% wt, preferably less than 0.1% wt, and more
preferably about 0.08% wt, are of a particular interest; [0080] a
boiling temperature, according to ASTM D-86, that is comprised
between 150.degree. C. and 500.degree. C., preferably between
175.degree. C. and 450.degree. C.; [0081] an abnormal peak in the
ASTM D-86 curb in the in the area of the peak of recycled solvent,
i.e. of the solvent that passes at least once through the process,
preferably in the 0 to 10% area of distilled volume, and more
advantageously in the area of 5% of distilled volume, appears to be
new and are of a particular interest; [0082] a total acid number,
according to ASTM 996, that is lower than 4, preferably lower than
1; and [0083] a cetane index over 40.
[0084] A third object of the present invention is constituted by
the family of new stabilized diesels showing: [0085] according to
ASTM method D6468, a stability for at least a day, or until it is
used; [0086] according to ASTM method D1500, a colour index that is
lower than 3; and [0087] an abnormal peak, in the ATM D-86 curb, in
the 0 to 10% area of distilled volume.
[0088] Preferably, new stabilized diesel of the invention has a
boiling temperatures range that is, according to ASTM D-86,
comprised between 150.degree. C. and 450.degree. C.
[0089] A fourth object of the present invention is made by the uses
of a stabilized fuel obtained by one of the process defined in the
first object of the present invention, or as defined in the second
and third object of the present invention, as: [0090] a fuel, or a
component in a blended fuel, such as a home heating oil, a low
sulphur marine fuel, a diesel engine fuel, a static diesel engine
fuel, power generation fuel, farm machinery fuel, off road and on
road diesel fuel; and/or [0091] a cetane index enhancer; and/or
[0092] a drilling mud base oil or component, preferably in the same
way as currently produced wide range diesels are used; and/or
[0093] a solvent or component of a solvent; and/or [0094] a diluent
for heavy fuels, bunker or bitumen; and/or [0095] a light lubricant
or component of a lubricating oil; and/or [0096] a cleaner or a
component in oil base cleaners; and/or [0097] a flotation oil
component; and/or [0098] a wide range diesel; and/or [0099] a
clarified oil; and/or [0100] a component in asphalt blends.
[0101] As an illustrative and non-limitative example of use as a
cetane index enhancer, if a refinery has 10,000 barrels of diesel
fuel with a cetane index of 38, adding 1,000 barrels of a new
stabilized oil of the invention, with a 60 cetane index, will bring
the combined 11,000 barrels to the specified 40 cetane index for
road diesel in North America.
[0102] As an illustrative and non-limitative example of use as
flotation component, when mixed with a product such as a refinery's
catalytic cracker fractionators bottom oil (CCFB). The ratio of
stabilized oil to CCFB can vary between 1/0.5 and 1/5 depending on
the type of ore entering the floatation cell, its concentration,
particle size, density and temperature.
[0103] In a preferred embodiment of the invention, the stabilized
diesel, are used in a mixture in combination with: [0104]
conventional diesel fuels, low sulphur diesels or wide range diesel
oils; and/or [0105] bitumen, light or heavy vacuum gasoil, heavy
fuels, bunker, tar or asphalt products; and/or [0106] refinery
intermediate streams such as catalytic cracker fractionators
bottoms; and/or [0107] organic solvents; and/or [0108] water and/or
additives to make specialty products such as drilling muds or
fractionating oils; and/or [0109] lubricating base oils, greases
and additives to make lube oils or greases.
BRIEF DESCRIPTION OF THE FIGURES
[0110] FIG. 1 is a simplified flow sheet that illustrates an
example of an embodiment of a process according to the
invention.
[0111] FIG. 2 is a block diagram illustrating the steps performed,
and the streams produced while operating in the preferred
embodiment described herein.
[0112] FIG. 3 is a distillation curve of raw and treated gasoil,
along with the distillation curves of pure and recycled solvent; of
the wide range diesel obtained by the process according to the
invention, as further specified in example 3 thereafter.
[0113] FIG. 4 is another distillation curve of raw and treated
gasoil, along with the distillation curves of pure and recycled
solvent, of the wide range diesel obtained by a process according
to the invention, as further specified in example 4 thereafter.
DETAILED DESCRIPTION
Preliminary Definitions
[0114] Unstable oils: are mixtures mainly made of hydrocarbons that
may degrade, for example by aging and/or heating and/or under
oxidizing conditions such as air exposition, oxygen exposition,
high temperatures and/or in the presence of catalysts. This
expression more particularly covers any mixtures of hydrocarbons
containing free radicals (and more specifically those mixtures
containing at least 50% wt of hydrocarbons), any oil which colour
deteriorates when exposed to heat or/and oxygen and/or other oils;
any oils produced by thermal cracking and/or oils obtained by
catalytic cracking and/or oils obtained by decomposition and/or
unstable oils obtained by degradation, and the mixtures of at least
two of the latter unstable oils; the processes of the invention are
suited for stabilizing any such unstable oils in the broader
sense
[0115] Wide range diesel: are oils mainly based on mixtures of
hydrocarbons with boiling points between 100.degree. C. and
500.degree. C.
[0116] Impurities: one or more chemical compounds that may be
unwanted in a mixture but that may finally assist the extraction
process.
[0117] Residues: contaminant and by-products obtained by reaction
and/or extraction, that are unwanted and to be eliminated.
[0118] GOn: gasoil (wide range diesels) in different steps of the
process of the invention, n is a numerical index, an integral
number, each of these integers corresponding to step of the process
and represent changes in composition.
[0119] Initial solvent: solvent introduced at the beginning of the
process and before its contamination by the solubilizing
component.
[0120] FIG. 1 is a simplified flow sheet that illustrates an
example of an embodiment of a process according to the invention.
As shown, pure DMF (dimethyl formamide) and/or recycled DMF is
introduced at the top of a continuously stirred contactor (1),
while the cracked oil to be treated is introduced at the bottom of
the column. A decanter (7) at the top of the column separates the
raffinate (16) from the DMF. A decanter (8) at the bottom of the
column separates the extract (17) from the oil to be treated. The
column has up to 30 compartments (2), separated from each other by
a disc with a hole in the middle (5). A stirrer shaft (3) equipped
with paddles (4) ensures good mixing of the solvent with the oil at
each level. The stirrer motor (6) is mounted at the top of the top
decanter (7). The oil level in the contacting column is held with a
level controller or simply with a column of liquid (9) using the
principle of communicating of vases. A jacket (13) surrounding the
extraction column maintains a constant temperature in the column
with steam or cooling water as required.
[0121] The raffinate (16) is routed to a vacuum distillation column
(10). The solvent and some light diesel exit through the top of the
column (18). They are cooled and condensed in a condenser (11), and
allowed to separate in an accumulator (12). The treated diesel (19)
exits from the bottom of the column, cooled, mixed with the oil
recovered from the solvent (23) and the light oil phase from the
accumulator (20) and sent to storage.
[0122] Another method to recover the solvent in the raffinate is to
centrifuge the raffinate. However, the separation between the
solvent and the oil is not as good as in the vacuum distillation
recovery method. The solvent losses increase.
[0123] The extract (17), drawn from the bottom of the bottom
decanter (8), is routed to another vacuum distillation column (14)
to recover the solvent and oil, exiting from the top of the column
(22), from the residue, exiting from the bottom of the column.
After passing through a separator (15), the solvent (24) is
recycled to the extraction column, along with the solvent (21) from
the oil recovery column. The oil (23) is routed to storage, along
with streams (19) and (20). The portion of the recycled solvent
boiling between 150.degree. C. and 250.degree. C. contains the
solutizing components.
EXAMPLES
[0124] The invention will now be further illustrated by mean of the
following non limiting examples 1 to 4. All four examples were
performed using the purification unit illustrated in FIG. 1 and the
reactive solvent extraction according to block diagram in FIG. 2.
Except for Example 1, wherein the methanol was introduced at the
bottom of the extraction column and the unstable oil at the top of
the extraction column. In FIG. 2, "S" refers to the solvent, "GO"
refers to the gasoil (or wide range diesel), "I" refers to the
impurities, "R" refers to the residue, and indicia "1, 2, 3, 4"
indicate varying concentrations and stages in the process.
[0125] Recycled DMF from the process, or from another source, along
with make-up DMF, is measured and introduced at the top of a
continuously stirred extraction column (a), 6 cm in diameter and
250 cm high. Wide range diesel produced from used oil in a thermal
cracker is measured and introduced at the bottom of the same
column. The column's 111 cm stirred section is divided into three
parts, each part containing ten cells. The cells are divided from
one another by a horizontal, doughnut-shape baffle. The stirrer's
shaft, in the middle of the column, is equipped with two paddles
per cell. The variable speed stirrer can turn at between 50 rpm and
150 rpm. The envelope around the contactor maintains stable
temperatures in the contactor with circulating water or steam. The
contactor operates at atmospheric pressure and 25.degree. C. The
stirrer turns at around 100 rpm. The decanter at the top of the
contactor column separates the raffinate from the solvent and the
decanter at the bottom of the column separates the extract from the
feed diesel. The level in the contactor is maintained with a
container, attached by a tube to the contactor, and placed at
variable heights. The extract and raffinate are weighted and sent
off plot for solvent recovery by vacuum distillation or
centrifuging at 10,000 rpm of both the extract and the
raffinate.
Example 1
Use of Methanol in the Process
[0126] Table I, Experiment 1, illustrates the best results obtained
using methanol as solvent. For this experiment, the column was
heated to 50.degree. C. (122.degree. F.).
[0127] Although the oil is stabilized, its sulphur content is
unchanged by the extraction process, and its flash point is reduced
below the 55.degree. C. (131.degree. F.) specified for heating oil
in Europe.
TABLE-US-00001 TABLE I EXPERIMENT No 1: Solvent at 99.9% wt
Methanol, Feed diesel/solvent ratio = 3/2 Feed Product Method Units
Diesel Diesel Density ISO 3675 Kg/l 0.85 0.84 Sulphur ISO 8754 %
m/m 0.366 0.366 Water ISO 10336 mg/kg 0.13 0.02 Total Acid Number
mg KOH/g 4.23 0.8 Flash Point ASTM D92 C. 69 26 Micro Carbon
Residue ISO 10370 % m/m 0.6 0.3 Cetane Index EPCN 322 53.9 59.1
Colour after 1 day ASTM D1500 8 3 exposed to air Colour after 5
months ASTM D1500 7 4 exposed to air
[0128] It is to be noted that the methanol extraction does not
reduce the sulphur content in the treated diesel.
Example 2
Use of DMF--Pure (99.9% wt)
[0129] Table II illustrates the results of three experiments using
the polarized solvent: dimethyl formamide (DMF).
[0130] In all experiments, the oil is stabilized and keeps its
light yellow colour for at least 6 months.
[0131] The flash point is unchanged in the extraction process. The
net heating value is also unchanged.
[0132] The sulphur content is reduced in all three tests. There is
a 63% reduction in sulphur content when pure solvent is used. When
a solvent that is not completely regenerated is used, the sulphur
removal is improved to meet the new European sulphur specifications
for heating oil of less than 0.1% wt. The water content of the oil
is also reduced to below the 250 ppm specification.
TABLE-US-00002 TABLE II EXPERIMENT No 2: Solvent at 99.9% wt DMF,
Feed diesel/solvent ratio = 1/1 Feed Product Method Units Diesel
Diesel Density ISO 3675 Kg/l 0.844 0.828 Sulphur ISO 8754 % m/m
0.322 0.119 Water ISO 10336 mg/kg 0.077 0.009 Total Acid Number mg
KOH/g 4.37 1.13 Flash Point ASTM D92 C. 69 66 Micro Carbon Residue
ISO 10370 % m/m 0.53 0.047 Cetane Index EPCN 322 54.8 60.7 Colour
after 1 day ASTM 1500 6 1 exposed to air Colour after 5 months ASTM
1500 7 1.5 exposed to air
Example 3
Contaminated DMF--at 83.4% wt in the Solvent Feed Stream
[0133] The same experiment as in example 1 and 2 is performed,
except that the solvent is at 83.4% wt DMF, Feed diesel/solvent
ratio=1/1.
TABLE-US-00003 TABLE III EXPERIMENT No 3: Solvent at 83.4% wt DMF,
Feed diesel/solvent ratio = 1/1 Feed Product Method Units Diesel
Diesel Density ISO 3675 Kg/l 0.844 0.834 Sulphur ISO 8754 % m/m
0.339 0.066 Water ISO 10336 mg/kg 0.098 0.012 Total Acid Number mg
KOH/g 1.54 0.15 Flash Point ASTM D92 C. 69 57 Cetane Index EPCN 322
57.1 60.2 Colour after 1 day ASTM 6 1 exposed to air D1500 Colour
after 5 months ASTM 7 1.5 exposed to air D1500
[0134] Note the abnormality in the 0 to 10% cut of the treated
gasoil, and the corresponding heads and tails in the recycled
solvent curve. The distillation curves in FIGS. 2 and 3 demonstrate
that the "solutizers" in this process have boiling points between
125.degree. C. and 200.degree. C. With another solvent, the
"solutizers" may have a different boiling point range.
Example 4
Contaminated DMF: 77.25% wt in the Solvent Feed Stream
[0135] The same experiment as in example 1 and 2 is performed,
except that the solvent contains 77.25% wt DMF, Feed diesel/solvent
ratio=1/1
TABLE-US-00004 TABLE IV EXPERIMENT No 4: Solvent at 77.25% wt DMF,
Feed diesel/solvent ratio = 1/1 Feed Product Method Units Diesel
Diesel Density ISO 3675 Kg/l 0.844 0.834 Sulphur ISO 8754 % m/m
0.315 0.086 Water ISO 10336 mg/kg 0.11 0.011 Total Acid Number mg
KOH/g 4.27 0.56 Flash Point ASTM D92 C. 53 60 Micro Carbon Residue
ISO 10370 % m/m 0.544 0.086 Cetane Index EPCN 322 54.2 60 Colour
after 1 day ASTM D1500 5.5 1.5 exposed to air Colour after 5 months
ASTM D1500 7 1.5 exposed to air
[0136] These experiments show that the impurities in the
incompletely regenerated solvent facilitate the mass transfer of
sulphur compounds from the gasoils to the solvent, as did the
solutizers for light oils in older patents.
[0137] The incompletely regenerated solvent was obtained by heating
the extract to 170.degree. C. in a thin film evaporator operating
at 120 mBar.
Example 5
Use as Cetane Index Enhancer
[0138] In the case of a refinery having 10,000 barrels of diesel
fuel with a cetane index at 38, adding 1,000 barrels of the new
stabilized oil, with a 60 cetane index, obtained in previous
example 4, will bring the combined 11,0000 barrels to the specified
40 cetane index for road diesel in North America.
Example 6
Use in a Drilling Mud Base Oil or Component
[0139] The new stabilized oil obtained in previous example 3 is
mechanically incorporated in a drilling fluid according to the
protocol described in U.S. Pat. No. 2,994,660, where diesel oil is
mixed with an aqueous phase containing a variety of chemicals. The
ratio of oil phase to water phase ranges from 80/20 to 35/65
preferably about 50/50 resulting in a new invert emulsion drilling
fluid.
Example 7
Use in as Flotation Oil Component
[0140] In order to get the floatation oil a refinery's catalytic
cracker fractionators bottom oil (CCFB) is mixed with the new
stabilized oil obtained in previous example 4. The ratio of
stabilized oil to CCFB can vary between 1/0.5 and 1/5 depending on
the type of ore entering the floatation cell. In the present
example the ratio of stabilized oil to CCFB is of 1/5 and the ore
is of the potash type. The temperature in the flotation cell is
about 15.degree. C.
[0141] The resulting flotation composition is advantageously used
in Canada.
Advantages of the Invention
[0142] The extraction process described in this patent stabilizes,
dries and neutralizes wide range diesel, while removing most of the
sulphur, chlorine, and water. As in other extraction processes
researched, complete regeneration of the solvent is difficult
because DMF or other solvents having a dipole moment greater than 2
disintegrate around 350.degree. C. (or at other temperatures
depending upon the selected solvent). Usually azeotropic
distillation is used, with water as the third component. However,
in this case, complete regeneration of the DMF is not necessary, or
even desirable, since the extraction process is more effective when
reaction products from previous passes are present in the
solvent.
[0143] This invention is a simple and low cost process to
stabilize, desulphurize, neutralize and dry unstable oils,
containing free radicals, such as those oils produced by thermal or
catalytic cracking of heavier oils. It can be used as a product oil
finishing process in a used oil plant, to debottleneck a
hydrotreating unit in a refinery or as a diesel oil finishing step
in a refinery. The extraction is performed at ambient temperatures
and pressures. The solvent can be regenerated with a simple vacuum
distillation or centrifuge. It does not require an azeotropic
distillation to achieve near complete regeneration, since complete
regeneration is not desired. Oxidation of the mercaptans, thiols,
and nitrogen compounds prior to their extraction from the oil is
not required. In the case of used oil plants, a gasoil meeting all
European heating oil specifications can be produced without
hydrotreating.
[0144] Although the present invention has been described with the
aid of specific embodiments, it should be understood that several
variations and modifications may be grafted onto the embodiments
and that the present invention encompasses such modifications,
usages or adaptations of the present invention that will become
known or conventional within the field of activity to which the
present invention pertains, and which may be applied to the
essential elements mentioned above.
* * * * *