U.S. patent application number 11/463182 was filed with the patent office on 2008-02-14 for process for improving the conversion of oxazolidones to alkanolamines.
This patent application is currently assigned to MPR Services, Inc.. Invention is credited to Arthur Lee Cummings, Robert Lee Horan, Michael L.H. Turoff, Scott William Waite.
Application Number | 20080039659 11/463182 |
Document ID | / |
Family ID | 38626442 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080039659 |
Kind Code |
A1 |
Turoff; Michael L.H. ; et
al. |
February 14, 2008 |
PROCESS FOR IMPROVING THE CONVERSION OF OXAZOLIDONES TO
ALKANOLAMINES
Abstract
There is provided a regeneration process for converting
oxazolidones such as hydroxypropyloxazolidone (HPOZD) to
alkanolamines such as di-isopropanolamine (DIPA) and CO.sub.2. An
amine stream containing HPOZD joins a stream that includes a
caustic solution. The combined stream is passed to a tank where the
caustic reacts with HPOZD to convert it to DIPA and CO.sub.2. The
conversion of HPOZD to DIPA and CO.sub.2 requires a ratio of at
least 2 moles of hydroxide for each mole of HPOZD in the solution.
The conversion reaction is carried out in a reaction vessel at a
temperature above 60.degree. C. The reaction mixture is held in a
feed tank for approximately 2 hours while being constantly mixed.
After the reaction is completed, the mixture is allowed to settle
which results in the virtually complete separation of the amine
phase (containing DIPA, and water) from the caustic phase. After an
appropriate settling interval, a portion of the caustic phase is
drawn from the reaction mixture as a waste/neutralization stream
while the other portion of the caustic phase and a very small
portion of the amine phase may be sent to a recycle tank for use in
subsequent reaction steps. The majority of the amine phase is
treated using ion exchange resins to remove excess cations from the
amine and clean amine is returned to the amine system.
Inventors: |
Turoff; Michael L.H.;
(League City, TX) ; Cummings; Arthur Lee; (League
City, TX) ; Waite; Scott William; (Reno, NV) ;
Horan; Robert Lee; (Houston, TX) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA, 101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Assignee: |
MPR Services, Inc.
|
Family ID: |
38626442 |
Appl. No.: |
11/463182 |
Filed: |
August 8, 2006 |
Current U.S.
Class: |
564/497 |
Current CPC
Class: |
C07C 213/02 20130101;
C07C 213/10 20130101; C07C 213/02 20130101; C07C 213/10 20130101;
C07C 215/12 20130101; C07C 215/12 20130101 |
Class at
Publication: |
564/497 |
International
Class: |
C07C 209/62 20060101
C07C209/62 |
Claims
1. A process for recovering alkanolamines comprising: reacting a
solution containing an alkanolamine such as di-isopropanolamine,
water, carbon dioxide and hydroxypropyloxazolidone, with a caustic
solution providing hydroxide ions in a ratio of 2.0 moles per mole
of hydroxypropyloxazolidone at a temperature between about
60.degree. C. and about 120.degree. C. to hydrolyze/convert the
hydroxypropyloxazolidone to di-isopropanolamine and carbonates
and/or bicarbonates, producing a caustic phase containing the
majority of the carbonates and/or bicarbonates and an amine phase
containing substantially all of the di-isopropanolamine.
2. The process according to claim 1 wherein at least a portion of
said caustic phase of said reacting step is recycled and used in
subsequent reaction steps as a source of some of the needed
hydroxide.
3. The process according to claim 1 wherein said ratio of hydroxide
ions to hydroxypropyloxazolidone is at least 2.2 moles of hydroxide
for each mole of hydroxypropyloxazolidone.
4. The process according to claim 1 wherein said temperature is
between about 80.degree. C. and about 100.degree. C.
5. The process according to claim 1 wherein said caustic solution
is potassium hydroxide but is not limited to that specific
caustic.
6. The process according to claim 1 wherein said alkanolamine is a
primary or secondary alkanolamines such as monoethanolamine,
diethanolamine, methyl monoethanolamine, or
di-isopropanolamine.
7. The process according to claim 1 wherein said amine solution
contains
8. The process according to claim 1 wherein said amine phase is
further treated by passing said amine phase through at least one
cation exchange resin bed to remove excess cations.
9. A process for regenerating an alkanolamine solution from an
amine recirculating system comprising: reacting a solution
containing an alkanolamine, water, carbon dioxide and
hydroxypropyloxazolidone and possibly a physical solvent such as
tetramethylene sulfone, with a caustic solution providing hydroxide
ions in a ratio of at least 2.2 moles of hydroxide ion for each
mole of hydroxypropyloxazolidone at a temperature between about
80.degree. C. and about 100.degree. C. to hydrolyze/convert the
hydroxypropyloxazolidone to di-isopropanolamine and carbonates
and/or bicarbonates producing an amine phase containing
di-isopropanolamine and a caustic phase containing carbonates
and/or bicarbonates; recycling at least a portion of said caustic
phase for a subsequent reaction step; passing said amine phase
through at least one cation exchange resin bed to remove excess
cations; and recovering said amine.
10. The process according to claim 9 wherein said caustic solution
is potassium hydroxide.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention provides a process for recovering
alkanolamines. More specifically, the present invention is an
improved process for converting an oxazolidone such as
hydroxypropyloxazolidone (HPOZD;
[3-(2-hydroxypropyl)-5-methyl-2-oxazolidinone]) to
di-isopropanolamine (DIPA).
[0003] 2. Description of Related Art
[0004] In the processing of gas and liquid streams, acid gas
impurities (typically hydrogen sulfide and carbon dioxide) are
removed by contact with an alkanolamine solution containing an
alkanolamines such as DIPA. Alkanolamine solutions are used because
of their relatively high absorption capacity of acid gases, and the
relative ease with which acid gases can be stripped from the
amine-containing solution.
[0005] One such process yields HPOZD, an impurity reaction product
of the DIPA and carbon dioxide (CO.sub.2). The reaction forming the
HPOZD molecule occurs with the simultaneous dehydration of one
water molecule (H.sub.2O) from the DIPA molecule. Other such
processes yield analogous oxazolidones using other
alkanolamines.
[0006] An existing process for converting this impurity (the HPOZD)
requires several lengthy stepwise heating and processing cycles at
dilute caustic (with corresponding cation) concentrations. This
process is tailored to convert the oxazolidone back to DIPA,
releasing CO.sub.2 into the amine solution to form carbonates
and/or bicarbonates, subsequently removing the majority of the
cations from the entire reaction solution using ion exchange
resins. Because of the concern of the capacity to remove cations
from the reaction solution, the concentration of the caustic
reactant is kept low, resulting in a process that has a typical
HPOZD to DIPA conversion efficiency of about 20% to 25% per
reaction process step. The entire reaction mixture including all
cations from the added caustic is processed through the ion
exchange resins. The overall process including rinsing and
regenerating the cation exchange resins adds considerable amounts
of water to the amine-containing solution which must be removed by
a distillation procedure.
[0007] This existing process treats a quantity of an
amine-containing solution obtained from an acid gas stripper column
used for acid gas removal. The amine-containing solution may be
composed of an alkanolamine such as DIPA, a physical solvent such
as tetramethylene sulfone, water, CO.sub.2 and the degradation
product identified as HPOZD. This solution is treated with a dilute
caustic solution, such as but not limited to potassium hydroxide
(KOH), at elevated temperatures at atmospheric pressure to
hydrolyze (add one molecule of H.sub.2O) to the HPOZD molecule and
simultaneously cleave the CO.sub.2 molecule out of the HPOZD
molecule, resulting in the production of free DIPA as well as
carbonates and/or bicarbonates. The DIPA generated by this process
is a benefit to the user in that it is a primary active ingredient
of the amine-containing solution used for acid gas removal. The
reduction of the HPOZD content of the amine-containing solution
used for acid gas removal by this process is a benefit in that the
HPOZD decreases the efficiency of the amine-containing solution to
perform its function of scrubbing acid gas from gas and/or liquid
process streams.
[0008] After processing the amine solution through the cation
exchange resins, it is returned as "clean amine" to the amine
circulation system where excess water and CO.sub.2 (from carbonates
and/or bicarbonates) are stripped from the solution.
BRIEF SUMMARY OF THE INVENTION
[0009] It is therefore the general object of the present invention
to provide a more efficient process for treating an
amine-containing solution that contains the HPOZD impurity,
converting the solution to a "clean amine" solution that can be
returned to the customer for reuse.
[0010] There is provided a reaction process for converting HPOZD to
DIPA and CO.sub.2. A rich (acid gas laden) amine stream is
introduced into an amine regenerator/stripper column. Steam is
generated by boiling the amine solution in the regenerator
reboiler. The steam generated from the reboiled amine is introduced
near the bottom of the amine stripper and passes upward through the
amine solution and the stripping vapor sweeps the acid gases away
from the amine solution and out of the top of the stripper. The
acid gasses are thereby stripped from the amine solution, producing
a "lean amine" solution. The hot lean amine stream exits the bottom
of amine stripper and is routed back to the absorber where it
absorbs additional acid gasses, becoming "rich" again, and
recirculates back to the regenerator/stripper column where it is
once again made "lean." Over the course of time, HPOZD is
accumulated in the amine solution due to a side reaction of
CO.sub.2 with DIPA.
[0011] To convert HPOZD back to DIPA, a portion of the lean amine
containing the HPOZD impurity is transferred into a reaction
container (feed tank) where it is mixed with a solution that
includes a caustic solution (typically but not limited to KOH) from
either a caustic supply vessel and/or a "recycle caustic" tank. The
combined streams are then aggressively mixed at prescribed
temperatures (see below) in the feed tank where the caustic reacts
with HPOZD to convert it to DIPA and CO.sub.2.
[0012] The conversion of HPOZD to DIPA and CO.sub.2
stoichiometrically requires two moles of hydroxide (OH.sup.-) for
each mole of HPOZD present in the solution to ensure a reasonably
complete conversion of the HPOZD. However, it has been found that
using that exact ratio does not provide sufficient driving force to
cause the reaction to go to completion. Achieving complete
conversion of the HPOZD back to DIPA requires a ratio of at least
2.0 but preferably more than 2.2 moles of hydroxide for each mole
of HPOZD in the solution and one mole of hydroxide for each mole of
"bound amine" (a protonated amine=an H.sup.+ bound to the amine)
present in the solution. More specifically, to have some residual
recoverable caustic value in the caustic phase of the reaction
mixture, a ratio of 2.5 moles of hydroxide for each mole of HPOZD
present and at least one mole of hydroxide for each mole of "bound
amine" present in the solution is desirable. (Note: A hydroxide
molecule reacts with a bound amine molecule to free the amine
molecule and yield one H.sub.2O molecule.)
[0013] The conversion reaction is carried out in a reaction vessel
at a temperature above 60.degree. C., preferably between 60.degree.
C. and 120.degree. C., and most preferably from 80.degree. C. to
100.degree. C. The reaction mixture is held in a feed tank at the
reaction temperature for approximately 2 hours while being
constantly mixed to maximize the contact between the caustic phase
and the lean amine solution. (It has been observed that the
concentrated caustic solution will virtually completely phase
separate from the amine solution without constant agitation,
therefore necessitating this aggressive mixing process in order to
ensure the reaction efficiency being achieved.) After the reaction
is completed, the mixture is allowed to settle which results in the
virtually complete separation of the amine phase (containing DIPA,
water, and other components of the amine-containing solution but
substantially free of HPOZD) from the caustic phase. After an
appropriate settling interval, approximately 1/2 of the caustic
phase is drawn off the bottom of the reaction mixture and placed in
a "waste/neutralization tank." The remaining portion of the caustic
phase and a very small portion of the amine phase are drawn off to
a "recycle tank" for use in a subsequent reaction cycle or sent to
the waste tank. The majority of the amine phase is passed through a
heat exchanger and then treated in ion exchange resin beds. The
resin beds use cation exchange resins to remove excess cations from
the amine and cleaned amine is returned to the amine system.
[0014] A major difference between the present invention and the
prior art is that the caustic phase is separated from the amine
phase prior to passing the amine solution through the ion exchange
resins. This separation is possible because a much higher caustic
concentration is being used than was used in the prior art
technique. This higher caustic concentration drives the conversion
reaction to a higher conversion efficiency, typically converting
95% to 100% of the HPOZD to DIPA, necessitating less reprocessing
of the amine-containing solution to eliminate HPOZD. An additional
benefit of this change is that the amine phase contains only a
small portion of the cations introduced into the reaction mixture
(thus the caustic phase contains the majority of the cations
introduced into the reaction mixture), therefore consuming much
less ion exchange capacity per processed amine volume. This results
in less rinse water returned to the amine system, less regeneration
acid consumption by the resin beds and less waste per processed
amine volume. Another side benefit of this present invention is
that carbonates and/or bicarbonates are concentrated in the caustic
phase which means that the majority of those species are not
returned to the amine system. When neutralization of the caustic
phase is performed, these carbonates and/or bicarbonates are
reacted with the neutralizing acid and CO.sub.2 is evolved from
this neutralization process which is vented harmlessly to the
atmosphere.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0015] Other object features and advantages of the present
invention will become apparent from the following detailed
description taken in conjunction with the drawings in which:
[0016] FIG. 1 is a schematic flow diagram which illustrates an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the inventions are shown. Indeed,
these inventions may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
[0018] Referring to FIG. 1, there is shown a schematic diagram of a
regeneration process for converting hydroxypropyloxazolidone
(HPOZD) molecule to di-isopropanolamine (DIPA) and CO.sub.2. A rich
amine stream (an amine containing considerable acid gasses
entrained) from an absorber (not shown) is introduced to amine
regenerator stripper column A through line 1. Internal stripping
steam is generated by reboiling the amine solution in the stripper
boiler (heat exchanger G) with a suitable heat medium 2. The lean
amine (amine with minimal acid gasses entrained) stream 3
containing HPOZD exits the stripper at a temperature from about
105.degree. C. to about 138.degree. C. depending upon the
concentration of the amine and the pressure in the stripper. The
steam generated from the stripper boiler G is introduced near the
bottom of the amine stripper column A through line 4 and passes
upward through the amine solution as a stripping vapor to sweep the
acid gasses away from the amine solution and out of the top of the
stripper A. The mixture of steam, hydrogen sulfide, and carbon
dioxide exits the stripper overhead through line 5.
[0019] The hot lean amine stream exits the bottom of amine stripper
A and a major portion of it passes through line 3 back to the amine
absorber (not shown). The remaining lean amine containing the HPOZD
impurity passes through line 6 where it may be blended with a
caustic solution either from a concentrated caustic supply
(additive trailer, line 19) and/or from a "recycle caustic tank"
(recycle tank C, line 16) which is then fed into the reaction tank
(feed tank B) through line 8 for subsequent processing according to
this invention where the caustic reacts with HPOZD to convert it to
DIPA and CO.sub.2.
[0020] The conversion of HPOZD to DIPA and CO.sub.2
stoichiometrically requires two moles of hydroxide (OH.sup.-) for
each mole of HPOZD present in the solution to ensure a reasonably
complete conversion of the HPOZD. However, it has been found that
using that exact ratio does not provide sufficient driving force to
cause the reaction to go to completion. Achieving complete
conversion of the HPOZD back to DIPA requires a ratio of at least 2
but preferably more than 2.2 moles of hydroxide for each mole of
HPOZD in the solution and one mole of hydroxide for each mole of
"bound amine" (a protonated amine=an H.sup.+ bound to the amine)
present in the solution. More specifically, to have some residual
recoverable caustic value in the caustic phase of the reaction
mixture, a ratio of 2.5 moles of hydroxide for each mole of HPOZD
present and at least one mole of hydroxide for each mole of "bound
amine" present in the solution is desirable. (Note: A hydroxide
molecule reacts with a bound amine molecule to free the amine
molecule and yield one H.sub.2O molecule.)
[0021] The reaction is carried out in feed tank B at a temperature
above 60.degree. C., preferably between 60.degree. C. and
120.degree. C., and most preferably from 80.degree. C. to
100.degree. C. The reaction mixture is held in feed tank B at the
reaction temperature while being constantly mixed so as to maximize
the contact between the caustic phase and the lean amine solution,
preferably for about 2 hours.
[0022] After the reaction is completed, the mixture is allowed to
settle which results in the virtually compete separation of the
amine solution (containing DIPA, water, and other components of the
amine-containing solution but substantially free of HPOZD) from the
caustic phase. After an appropriate settling interval, a portion
(preferably approximately 1/2) of the caustic phase is drawn off
the bottom of the reaction mixture and is pumped by pump 10 through
lines 9, 11, 14, and 13 to the waste tank F for use later in
neutralization of acids processed through cation exchange resins or
to be neutralized by acid from the acid trailer (through a pump and
a line not shown) to create a bio-remedial, non-hazardous waste
stream that can be pumped through pump 17 to a waste treatment
plant as a potassium sulfate and/or potassium carbonate and/or
potassium bicarbonate salt solution. The remaining portion of the
caustic phase and a very small portion of the amine phase are
pumped by pump 10 through lines 9, 11, 14, and 15 to the recycle
tank C where it can be used for subsequent reaction steps or it can
be pumped through lines 16, 14, and 13 to the waste tank F. The
majority of the amine phase is pumped by pump 10 through lines 9
and 12, through the heat exchanger H to cool the mixture, then
through the cation exchange resin vessels D and E which use cation
exchange resins (that may be the same or different) to remove the
majority of the cations from the "clean amine" solution. This clean
amine solution is subsequently returned through line 18 to the
amine system for further use.
[0023] Suitable cation exchange resins include for example strong
acid cation resins in the H.sup.+ form such as Purolite C100, C145,
SGC100, Sybron Ionac.RTM. C-251, CFP-110, Miles Wofatit KPS, Miles
Lewatit S-100, Dowex.RTM. HCR-S/W2, Rohm & Haas Duolite
C20/225, Resin Tech CG8, CG10 and the like.
[0024] Prior to regenerating the resins, the amine containing
solution is rinsed off of the resin beds with water from line 24
and sent to the amine system. Any amine occupying resin exchange
sites may also be removed by a caustic stripping process as
described in U.S. Pat. No. 5,368,818 by drawing caustic from the
additive trailer or some other source.
[0025] The cation exchange resins are regenerated by drawing acid
from the acid trailer through line 23, blending with water from
line 24 as needed, using a pump (not shown in FIG. 1), pumping the
acid solution through line 12 to the resin beds to exchange the
K.sup.+ cations on the resin for H.sup.+ cations. The exchanged
K.sup.+ cations are now in a salt solution which is passed through
line 22 and 13 to waste tank F. After the regeneration process is
completed, the resin beds are rinsed with water from line 24
through resin beds D and E to waste tank F via lines 22 and 13.
[0026] This entire processing cycle may be repeated multiple times,
and for subsequent processing cycles, the material in recycle tank
C is transferred back into feed tank B through use of a pump (not
shown in FIG. 1) where it is combined with additional lean amine
solution laden with HPOZD from the amine stripper and additional
fresh caustic via line 19 from the additive trailer. By knowing the
HPOZD content and the bound amine content of the amine solution
added to the feed tank, the hydroxide requirement to achieve
complete conversion of the HPOZD can be determined.
[0027] It should be understood that the amine regenerator (amine
stripper column A) may be sized to regenerate amines from one to as
many as 20 or so absorbers. The lean amine stream 3 would be used
in all absorbers. The amine-containing solution may come from the
exit of the stripper as shown in FIG. 1 or it may come from the
reboiler circuit or any point in the lean amine circulation system
or a storage vessel where a contaminated amine containing solution
has been collected for processing.
EXAMPLES 1-3
[0028] These three examples illustrate actual laboratory
experimentation on samples from three different locations with the
intention of implementing the current invention's technology to
perform the amine reclamation. Prior to testing, each amine
solution was analyzed for % oxazolidone by gas chromatography,
density, and % bound amine and % DIPA by acid/base titration.
[0029] The following parameters are conditions under which these
experiments were performed for each sample individually: [0030] An
aliquot of the sample was selected and computations were made to
determine the amounts of these listed species in that aliquot. This
aliquot was placed into a 500-mL three necked boiling flask. A
calculation was made to compute what amount of hydroxide (in the
form of a 50% by weight potassium hydroxide solution) would be
needed to present a ratio of 2.5 to 1 of hydroxide ions to
reactable species. The amount of potassium hydroxide thus computed
was added to the aliquot of amine in the boiling flask. A magnetic
stirring bar was added to the flask, then the flask was placed in a
hot water bath on top of a hot-plate stirring motor. A cold water
condenser was placed into the center neck of the flask and a
thermometer placed into one of the side necks of the flask. The
third neck of the flask was capped with a stopcock. The flask's
contents were vigorously stirred to completely mix the amine and
caustic phases. [0031] The flask and the water bath were heated to
approximately 80.degree. C. (plus or minus 3.degree. C.) and held
at that temperature for approximately two hours while the solution
was continuously stirred to ensure complete mixing contact of the
amine and caustic phases. [0032] After the two hour mixing period
was completed, the flask was removed from the heating and
condensing apparatus and the solution was poured from the flask
into a 500-mL separatory funnel. The phases were allowed to
completely separate in the funnel and the bottom (caustic) phase
was drawn off from the solution and segregated for subsequent
analysis.
[0033] The reaction product amine phase was analyzed for residual
oxazolidone by gas chromatography, DIPA by acid/base titration,
residual strong cations (as potassium) and excess hydroxide by
acid/base titration.
[0034] The reaction product caustic phase was analyzed for residual
free hydroxide, carbonates and bicarbonates by acid/base titration
but that information is not reported herein. This free hydroxide
computation is important for the use of this phase as part of the
subsequent batch's hydroxide source material.
[0035] Tabulated results of the analysis of each amine phase are
shown in Table 1.
TABLE-US-00001 TABLE 1 Description/Sample ID Example 1 Example 2
Example 3 Sample Density, g/mL 1.082 1.115 1.080 % Oxazolidone
starting conditions 12.25 18.83 29.78 Oxazolidone starting
conditions, mole/kg 0.657 0.951 1.604 Oxazolidone starting
conditions, mole/L 0.711 1.060 1.732 Bound Amine, starting
conditions, mole/kg 0.044 0.026 0.049 Bound Amine, starting
conditions, mol/L 0.048 0.029 0.053 Total constituents to react
with KOH, mole/L 0.759 1.089 1.785 % DIPA in amine phase prior to
reaction, w/w 49.61 34.86 47.57 DIPA in amine phase prior to
reaction, mol/kg 3.725 2.617 3.572 DIPA in amine phase prior to
reaction, mol/L 4.030 2.919 3.857 Hydroxide Dosage Ratio: Mole:mole
ratio of 2.5 2.5 2.5 OH.sup.- to reactable constituents Reacted
Product's amine phase density, g/mL 1.082 1.110 1.067 Reacted
Product's amine phase, % 0.200 0.590 0.190 Oxazolidone remaining,
w/w Reacted Product's amine phase, Oxazolidone 0.013 0.037 0.012
remaining, mole/kg Reacted Product's amine phase, Oxazolidone 0.014
0.041 0.013 remaining, mole/L % DIPA in Reacted Product's amine
phase, 57.61 50.60 69.05 w/w Reacted Product's amine phase, DIPA,
4.325 3.799 5.184 mole/kg Reacted Product's amine phase, DIPA,
4.679 4.215 5.532 mole/L % Destruction of Oxazolidone 98.09 96.12
99.26 Net increase in DIPA concentration, mole/L 0.65 1.30 1.67 Net
absolute increase in DIPA concentration, % by 8.00 15.74 21.48
wt
[0036] The results show a significant decrease in oxazolidone and a
corresponding increase in DIPA concentration.
Comparison of Prior Art and the Present Invention
[0037] Samples of contaminated amine from various locations were
obtained to compare the reduction of oxazolidone concentration in
their process streams using the prior art and the new invention.
These next two examples (example 4 in table 2 and example 5 in
table 3) illustrate the contrast between the prior art and the
predicted results using the present invention. The sixth example
(table 4) contrasts expectations per the prior art and the actual
observations during the commercial scale trial of the present
invention.
EXAMPLE 4
[0038] System Size: 49,100 gallons
[0039] Starting Oxazolidone level: 20.4%;
[0040] Targeted end value Oxazolidone level: 8.0%
[0041] Oxazolidone incursion rate: 1 lbmol/day
TABLE-US-00002 TABLE 2 Prior Art, Actual Values (Commercial Current
Invention, Description Scale) Predicted Values Cycles to perform
job to specified parameters 56 17 Days to perform job to specified
parameters 23 7 Fresh 50% KOH required for reacting with 4,000
5,900 oxazolidone to convert it to amine, gallons Fresh 50% KOH
required for neutralization of 4,872 0 resin regenerant waste,
gallons Fresh 50% KOH for stripping amine off of 1,120 340 resin
prior to regeneration, gallons Recycled KOH made available by
process for 0 1,475 neutralization of acid waste, gallons Recycled
KOH required for neutralization of 0 1,037 resin regenerant waste,
gallons Fresh 50% KOH total usage, gallons 9,992 6,240 50% KOH
predicted in brine solution, gallons 0 438 (what does not get
neutralized by the regenerant waste) 93% H.sub.2SO.sub.4 needed for
regeneration of resin, 3,920 1,071 gallons 93% H.sub.2SO.sub.4
needed for neutralization of waste KOH 0 169 stream, gallons 93%
H.sub.2SO.sub.4 total usage, gallons 3,920 1,240 Effluent brine
generated by process, gallons 295,000 94,000 Water introduced to
amine system, gallons 47,264 14,348
[0042] The results show the predicted dramatic reduction in water
usage, caustic usage, acid usage, effluent brine production, and
reaction cycles, and processing time, when practicing the method of
the present invention.
EXAMPLE 5
[0043] System Size: 73,600 gallons
[0044] Existing Oxazolidone level: 23 wt %;
[0045] Targeted end value Oxazolidone level: 8 wt %
[0046] Oxazolidone incursion rate: 3 lbmol/day
TABLE-US-00003 TABLE 3 Prior Art Actual Current Values Invention
(Commercial Predicted Description Scale) Values Cycles to perform
job to 52 35 specified parameters Days predicted to perform job to
specified 28 12 parameters Fresh 50% KOH total usage, gallons
24,700 15,700 93% H.sub.2SO.sub.4 total usage, gallons 6,240 3,243
Effluent brine generated by 509,824 269,863 process, gallons Water
introduced to amine system, gallons 295,008 64,125
[0047] The results show the predicted dramatic reduction in water
usage, caustic usage, acid usage, effluent brine production, and
reaction cycles, and processing time, when practicing the method of
the present invention.
EXAMPLE 6
[0048] System Size: 13,200 gallons
[0049] Starting Oxazolidone level: 37 wt %;
[0050] Targeted end value Oxazolidone level: 4.4 wt %
[0051] Oxazolidone incursion rate: 0.8 lbmol/day
TABLE-US-00004 TABLE 4 Current Invention, Prior Art, Actual Data
Description Predicted Values (Commercial Scale) Cycles to perform
job to specified parameters 66 17 Days predicted to perform job to
specified 27 11 parameters Fresh 50% KOH total usage, m.sup.3 38 28
93% H.sub.2SO.sub.4 total, m.sup.3 18 8 Effluent brine generated by
process, m.sup.3 1,300 180 Water introduced to amine system,
m.sup.3 280 72 Water usage total, m.sup.3 1,850 126
[0052] The results show the actual dramatic reduction in water
usage, caustic usage, acid usage, effluent brine production, and
reaction cycles, and processing time, when practicing the method of
the present invention.
[0053] Many modifications and other embodiments of the inventions
set forth herein will come to mind to one skilled in the art to
which these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are
not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *