United States Patent [19]
Kenney et al.
[11] Patent Number:
[45] Date of Patent:
4,582,613
Apr. 15, 1986
[54] USE OF COPPER (II) OXIDE AS SOURCE OF
OXYGEN FOR OXIDATION REACTIONS
[75] Inventors: Charlie W. Kenney, Littleton; Laura
A. Uchida, Lakewood, both of Colo.
[73] Assignee: Resource Technology Associates,
Boulder, Colo.
[21] Appl. No.: 653,344
[22] Filed: Sep. 24, 1984
[51] Int. C1.4 C02F 1/72
[52] U.S. Ct 210/761; 210/758;
210/904; 210/909;423/42; 75/117
[58] Field of Search 210/758, 761, 762, 763,
210/721,909,711,904; 75/117; 423/42, 35,
604; 568/724
[56] References Cited
U.S. PATENT DOCUMENTS
1,925,367 9/1953 Booth 568/747
2,944,396 7/1960 Barton et al. 2101763
3,606,999 9/1971 Lawless 210/761
3,853,759 12/1974 Titmas 210/761
4,195,189 3/1980 Earley 5681730
FOREIGN PATENT DOCUMENTS
2534458 2/1976 Fed. Rep. of Germany 210/904
50-106862 8/1975 Japan 210/761
51-24575 2/1976 Japan 210/761
785202 12/1980 U.S.S.R 210/763
Primary Examiner-Benoit Castel
Attorney, Agent, or Firm-Sheridan, Ross & McIntosh
[57] ABSTRACT
This invention comprises a wet oxidation process utilizing
copper (II) oxide as the sole oxygen source. In particular
the destruction and detoxification by oxidation
of toxic materials such as cyanide, hydrocarbons, halogenated
hydrocarbons, and dioxins contained in typically
aqueous streams by using copper (II) oxide is
contemplated. The preferred embodiment involves adding
the copper (II) oxide to the feed stream containing
the toxic materials and reacting the stream under elevated
pressure and elevated temperature conditions to
substantially oxidize the toxic materials to less toxic or
innocuous compounds. The oxidation process can be
accomplished in a vertical tube reactor system, wherein
the necessary pressure for the wet oxidation is achieved
by hydrostatic head pressure inherent in the system.
26 Claims, No Drawings
4,582,613
This invention provides processes for the oxidation
treatment ofliquid feed streams containing toxic materials,
such as cyanides, and including hydrocarbons such
as phenols, halogenated hydrocarbons, such as pentachlorophenol,
and dioxins. Such feed streams are typically,
but not necessarily, aqueous. The feed stream
containing the toxic material is mixed with copper (II)
oxide and this mixture is subjected to conditions of
elevated temperature and elevated pressures for a time
sufficient such that the toxic materials are detoxified
and destroyed by oxidation. The treated feed stream is
substantially free of the toxic materials and is typically
suitable after treatment for acceptable disposal. The
only external source of oxygen is the copper (II) oxide,
and no external additional source of oxygen is required.
The copper (II) oxide provides the oxygen necessary
for the oxidation reaction, with a concomitant reduction
of the copper (II) oxide to copper (I) oxide or
elemental copper.
In another embodiment of the invention, the process
steps are conducted in a vertical tube reactor system,
wherein the necessary pressure is achieved by hydrostatic
head pressure inherent in the system.
In other embodiments, the reduced copper is recovered
from the oxidized streams and regenerated and
2
temperatures and pressures and moving reaction components.
A vertical tube reactor configuration was considered
as an economic means for achieving desired
reaction conditions. U.S. Pat. No. 4,272,383 to
5 McGrew, along with the various references cited
therein, disclose such reactor configurations, along with
particular processing conditions for treatment of particular
wastes. Deep well reactors have been used to accomplish
wet oxidation, and a vertical tube subsurface
10 reactor environment useful for controlled chemical
oxidation reactions was disclosed in U.S. Pat. No.
3,606,999 to Lawless, but this patent does not teach
detoxification ofhazardous waste. Use of a vertical tube
reactor system could provide the necessary pressure by
hydrostatic head pressure inherent in the system, but
such reactors do not allow for agitation or mixing of the
reaction components as they provide only "plug" or
laminar flow. Since detoxification of many of the waste
materials involves decomposition of molecules or complexes
which are difficult to break, and thought to require
agitation of the reaction mixture in order to
achieve reasonably complete oxidation, the usefulness
of a vertical tube reactor for this purpose was by no
means certain. Surprisingly, however, the vertical tube
reactor was found to be effective in achieving substantially
complete detoxifying even on such stubborn materials
as copper and silver complexes with cyanide.
However, one disadvantage of the subsurface vertical
tube reactor system is the introduction of an oxygencontaining
gas at these depths. It would be advantageous
to have a system where the oxygen source is
contacted with the waste feed stream prior to downflowing
the waste stream into the vertical tube reactor
system.
Thus, an object of one embodiment of this invention
is to provide an oxidation process for the detoxification
of hazardous organic and inorganic waste contained in
feed streams by using a vertical tube reactor system in
which the only external oxygen source is non-gaseous
copper (II) oxide.
SUMMARY OF THE INVENTION
1
USE OF COPPER (II) OXIDE AS SOURCE OF
OXYGEN FOR OXIDATION REACTIONS
FIELD OF INVENTION
This invention relates to the detoxification of toxic
substances by oxidation utilizing copper (II) oxide as the
single oxygen source for the oxidation reactions.
BACKGROUND OF THE INVENTION
Wet oxidation is a series of oxidative and hydrolysis
reactions which occur at elevated temperatures and
pressures, typically in an aqueous environment. Wet
oxidation is a well-known process for use in purifying
waste waters, such as sewage sludge and manufacturing 15
waste process waters. Further, it is known that wet
oxidation can be accomplished by use of a catalyst with
an oxygen-containing gas at elevated temperatures and
pressures. U.S. Pat. No. 4,141,828 to Okada et aI.,
teaches a process of wet oxidation of ammonia-contain- 20
ing waste water by contacting the waste water with an
oxygen-containing gas and a catalyst and subjecting the
mixture to the elevated temperatures and pressures.
U.S. Pat. No. 4,072,608 to Farha, Jr. et al., teaches a
process for the purification of water polluted by organ- 25
ics and oxygen-containing compounds. This process
comprises contacting the waste water and an oxygencontaining
gas with an iron group metal promoted by a
solid copper-magnesium-oxygen spinel structure catalyst
at elevated temperatures and pressures. U.S. Pat. 30
No. 4,062,772 to Box, Jr. et aI. also relates to a process
for the purification of organically polluted waters by
contacting the waste waters with a solid copper-magnesium-
oxygen catalyst promoted with bismuth and an
oxygen-containing gas at elevated temperatures and 35
pressures. U.S. Pat. No. 4,268,399 to Box, Jr. et aI.,
relates to a process for oxidizing organically polluted
waters by contacting the polluted waters with an oxygen-
containing gas and a catalyst consisting of zinc,
titanium, and oxygen. 40
None of these references teach a process of wet oxidation
using copper (II) oxide (CuO) as the single oxygen
source for the oxidizing reactions.
Accordingly, it is an object of this invention to provide
a wet oxidation process, particularly for the detoxi- 45
fication of waste streams, utilizing copper (II) oxide as
the single oxygen source for the reactions.
As a result of major environmental problems occurring
today, inorganic and organic waste material that·
are generally carried in aqueous streams must be detoxi- 50
fied before disposal. Waste compounds that pose environmental
disposal problems include cyanide-bearing
solutions; halogenated hydrocarbons, such as pentachlorophenols
prevalent in wood processing waste;
hydrocarbon wastes from petrochemical plants and 55
refineries, such as phenolic compounds; and dioxins.
However, effective detoxification and destruction of
the toxic waste materials require costly chemicals and/
or elevated pressures which make such a system quite
expensive. 60
The high pressures required for wet oxidation reactions
have been previously achieved in autoclave-type
reaction vessels which allow for agitation and mixing of
the reaction components. However, such systems require
large amounts of energy to achieve the required 65
temperatures and pressures and to pump reaction components
into the pressurized vessels. It was desirable to
find a more economical way of achieving the required
(i)
(ii)
4,582,613
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS
C6CIsOH+HZO+9CuO-.6COZ+5HCI+9Cu'
3
recycled as copper (II) oxide for use in the process steps
of the invention.
4
Dioxin compounds, such as 2,3,7,8-tetrachlorodibenzo-
p-dioxin(2,3,7,8-TCDD) found in the discontinued
herbicide 2,4,5-trichlorophenoxyacetic acid; 2-
chlorodibenzo-dioxin (2-CDD); 1,2,3,4-tetra-
5 chlorodibenzo-dioxin (1,2,3,4-TCDD); and 2,7-
Typical feed material for the processes of the present dichloro-dibenzo-dioxin (2,7-DCDD) are also effecinvention
are toxic organic and inorganic compounds tively detoxified.
capable of being destroyed or beneficially altered by In addition, cyanide-containing solutions may also be
oxidation, such as cyanides, including free cyanide, beneficially treated according to the processes of this
metal-cyanide complexes, thiocyanates, and thiosul- 10 invention to less toxic-substances.
fates; halogenated hydrocarbons, such as pentachloro- Although the process of this invention is described
phenol (PCP); petrochemical plants and refinery waste, with respect to the above specific toxic substances, it is
such as phenolic compounds; and dioxins. The toxic not limited thereto and may be advantageously used to
organic and inorganic compounds used as feed material oxidize all substances which may be beneficiated by
are chemically oxidizable substances that convert dur- 15 conventional wet oxidation procedures.
ing the oxidation reaction to less toxic or innocuous Typically, the oxidation process is conducted at a
products. By oxidation, as used herein, is meant a reac- temperature offrom about 70· C. to about 370· C., more
tion in which oxygen reacts with the toxic material to preferably from about 200· C. to about 350· C., and
form less toxic or innocuous compounds. When the most preferably at a temperature of from about 290· C.
toxic material is contained in an aqueous medium, hy- 20 to about 350· C. The pressures are typically in the range
drolysis reactions also take place. As used herein, mate- of from about 400psi to about 3200 psi, more preferably
rials defined as toxic andlor hazardous can include from about 1000 psi to about 2400 psi. As will be underchemical
compounds or groups of compounds that are stood by those skilled in the art, the time may be adgenerally
regarded as having toxic properties, either justed based on considerations of process variables,
when ingested, inhaled, or absorbed via the skin. Ex- 25 such as the amount of CuO added, the percent of toxic
eluded from this list would be radioactive substances. materials present, and the temperatures and pressures
For purposes of this invention innocuous or harmless chosen as operating conditions. Generally, at higher
means not toxic. The feed material is typically con- temperatures and pressures, less time is required for the
tained in an aqueous stream, usually a waste aqueous process.
stream derived from a manufacturing or ore treatment 30 The pH of the feed streams will typically be from
process. Typical. amounts of toxic material in the stream about 2 to about 12, dependent upon the type and conare
from about I ppm to about 15 gil, although streams centration of feed material contained in the stream.
containing more or less toxic materials may be treated In the preferred embodiment, the copper (II) oxide,
according to the processes of this invention. which has been reduced to copper (I) oxide or elemen-
In the initial step, the toxic material-containing 35 tal copper from the oxidation process, is recovered and
stream, typically aqueous, is mixed with a slurry of separated from the oxidized stream. The reduced copcopper
(II) oxide in water or other liquids. The amount per can be treated by means known in the art to regenerof
copper (II) oxide added to the waste stream depends ate copper (II) oxide, which is then suitable for recyupon
the amount of toxic material to be oxidized. Typi- cling to the steps of this process.
cally this amount is the stoichiometric amount, or 40 The process of the invention requires a reactor or
greater, of oxygen necessary to oxidize the toxic materi- other apparatus into which the cupric oxide is added
als. and in which the stream is heated and pressurized. A
The copper (II) oxide-loaded stream is next contacted number of reaction pressure apparatuses known in the
at elevated temperatures and elevated pressures and for art may be used, as for example: a stirred pressure vesa
time sufficient to detoxify the toxic materials con- 45 sel, a pipeline reactor, or a free-flowing pressurized
tained in the stream. The copper (II) oxide supplies the absorption column.
oxygen necessary for the reaction with a concomitant In one embodiment of the invention, the process steps
reduction of the copper (II) oxide to copper (I) oxide or are carried out in a vertical tube reactor system,
elemental copper. After the heat and pressure treat-' wherein the necessary pressure is achieved by hydroment,
the stream, particularly if aqueous, may be suit- 50 static head pressure inherent in the system. The reactor
able for acceptable disposal without further treatment design is typically vertical, with a downcomer portion
as the stream is substantially free of the toxic materials. which is generally a cylindrical pipe, and a riser portion
Phenol is a common constituent of petrochemical and which is also generally a cylindrical pipe. Another conrefinery
hydrocarbon wastes. When phenol is contained figuration for a vertical reactor system is aU-tube
in an aqueous feed stream, the stoichiometric amount of 55 wherein one leg comprises the downcomer and the
copper (II) oxide supplied oxygen required to com- adjacent leg comprises the riser. Another configuration
pletely oxidize phenol is generally about 1.0 to about is an annular tubing arrangement wherein the down-
1.5. The reaction occurs according to the following comer generally comprises an internal cylindrical pipe
equation: and the riser comprises a concentric outside annular
60 ring. Suitably lined deep bore holes or well holes can be
utilized as the process apparatus and the desired pressure
can be achieved by conducting the reaction at a
pre-selected underground depth. It is not necessary that
the reactor configuration be truly vertical, as long as the
feed material is introduced into the reactor system at a
location sufficiently elevated from the primary reactor
zone portion of the system so as to generate sufficient
hydrostatic head pressure. Utilizing the inherent hydro-
When a halogenated hydrocarbon is contained in the
aqueous feed stream such as pentachlorophenol (PCP),
the reaction of the wet oxidation of PCP is as follows: 65
4,582,613
5
static head pressure of the system significantly reduces
the cost of the operations, making the process more
economically feasible.
The dimensions of the downcomer and riser portions
6
mum phenol removal with cupric oxide was achieved at
a temperature of about 3380 C. An insufficient quantity
of gas was available at the end of the runs with cupric
oxide for an analysis of organic vapors.
TABLE I
Wet Oxidation of Phenol
Summary of Test Conditions and Results
Test No. Feed I 2 4
Input 0.74 g phenol 0.74 g phenol 0.76 g phenol 0.74 g phenol 0.87 g phenol
Sample(I*) CuO 11.34 g CuO 11.35 g CuO 11.34 g CuO 11.34 g CuO
Excess 02, no. times stoic for C6HSOH 1.30 1.26 1.30 I.lO
Test Conditions
Preheat, min 145 58 54 87
Temp, 'C. 316-320 242-248 279-280 337-340
Pressure, psig 1550-1610 500-540 875-910 2050-2125
Residence time, min 44 80 70 78
Products
Gas
Volume, ml 261 211 211 211
Pressure, psig 11.22 0.39 0.19 23
% C02(*3) 6.8 (*4) (·4) 40
% 02(*3) 3.4 (*4) (·4) 6.0
Liquor (rinse)
Volume, ml 77(320) 94(375) 88(320) 67(540)
pH 4.6 4.95 5.2 4.4 4.6
Phenol, mgll 6720 2660(60.9) 4090(62.5) 3590(89.1) 712(22.4)
TOC,mgll 5560 2440(69) 3660(119) 3230(90) 845(36)
COD, mgll 17,200 7400(171) 11,060(276) 9730(267) 1940(80)
Cu, mgll 0.02 50.1(1.91) 1.42(0.28) 2.55(0.30) 43.5(3.00)
% reduction of phenol(·2) 66.6 40.9 48.7 92.4
% reduction in TOC(*5) 62.2 31.9 43.7 88.4
% reduction in COD(*6) 63.7 35.3 45.3 91.4
(·])Dissolved in 100 ml deionized water.
{·2)Assume 9.29% degradation of initial sample and no phenol in gas phase.
(*3)Orsat Analysis.
(*4)Insufficient sample for analysis.
(*5)Assume initial TOC = 75.1% of initial sample phenol concentration.
(*6)Assume initial COD = 2.324 X initial sample phenol concentration.
EXAMPLE 2
Pentachlorophenol (PCP) Tests
Tests were completed to determine the effects of
temperature, time, pH, and the use of a solid oxygen
carrier on PCP destruction. The tests were run in a
600-ml stainless steel autoclave equipped with a glass
liner and titanium or Hastelloy C wetted parts. A solution
containing I gram per liter ofPCP was used as feed
for the tests. In Test 1, the solution was heated with
mixing under a nitrogen atmosphere to the desired reaction
conditions; then 100 psi of oxygen was added. In
Test 2, the oxygen gas was not added, instead, CuO, the
solid oxygen carrier, was added to the solution. To end
the tests, the reactor was cooled rapidly by removing
the heat source and running water through a cooling
loop. The aqueous solution was removed and the reactor
was rinsed with methanol to recover residual PCP.
Both the aqueous and alcohol solutions were analyzed
for PCP using a gas chromatograph/mass spectrometer.
Test conditions and results are summarized in Table
2.
EXAMPLE I
Tests were run on phenol, C6H50H, a water soluble 50
organic, using CuO as a solid oxygen donor. All tests
were run in a 300-ml stainless steel Parr stirred autoclave.
To start a test, the phenol and deionized water
and copper (II) oxide were placed in the autoclave and
the system was purged with nitrogen. The autoclave 55
was heated to the required temperature. The temperature
was maintained for the allotted time and the autoclave
was cooled by removing the heating mantle and,
in some cases, by using an air blower or water bath.
When the system reached room temperature, a gas 60 TABLE 2
sample was analyzed by either gas chromatography or --------.Su.m:m.ar:y o=f P=CP T:e:st.Re.su:lts.--------
Orsat (gas absorption). After gas samples were taken, pCP
the slurry was filtered and the filtrate analyses included Test Temp Time Removal(*I)
pH, phenol, total organic carbon (TOC), chemical oxy- No. 'C. min % Comments
gen demand (COD), and copper. 65 I 310 60 92.9
Table 1 contains a summary of test conditions and 2 310 60 97.2 CuO oxygen carrier
results. Reduction of phenol, TOC, and COD were (*I)Removal based on PCP recovered in methanol wash solution.
primarily functions of reaction temperature. The maxiof
the reaCtor system are designed so that the feed 35
stream flow rate and reactor residence time are sufficient
to accomplish the oxidative reaction. The reactor
length is primarily a function of the desired reaction
pressure.
Upon exiting the riser portion of the reactor system, 40
the reduced copper exists in precipitated form in the
oxidized aqueous stream. The process aqueous stream is
preferably separated from the copper, and the copper
may then be treated to regenerate copper (II) oxide for
recycle to the process. 45
The following examples are provided by way of illustration
and not by way of limitation.
4,582,613
7
Although the foregoing has been described in some
detail by way ofillustration and example for purposes of
clarity of understanding, it will be obvious that certain
changes and modifications may be practiced within the
scope of the invention, as limited only by the scope of 5
the appended claims.
What is claimed is:
1. A process for treating a liquid feed stream containing
toxic materials said process comprising contacting
said stream with copper (II) oxide as the only external 10
source of oxygen at a temperature of from'hbout 70· C.
to about 370· C. and a pressure offrom about 400 psi to
about 3200 psi and for a time sufficient to substantially
destructively oxidize and detoxify said materials.
2. A process according to claim 1 wherein said toxic 15
materials are cyanides.
3. A process according to claim 1 wherein said toxic
materials are hydrocarbons.
4. A process according to claim 3 wherein said toxic 20
materials are phenolic compounds.
5. A process according to claim 3 wherein said toxic
materials are halogenated hydrocarbons.
6. A process according to claim 5 wherein said halogenated
hydrocarbon is pentachlorophenol. 25
7. A process according to claim 3 wherein said toxic
materials are dioxins.
8. A process according to claim 1 wherein said feed
stream is aqueous.
9. A process according to claim 1 wherein said feed 30
stream is non-aqueous.
10. A process according to claim 1 wherein said CuO
is in at least a stoichiometric amount necessary to oxidize
the materials.
11. A process according to claim 1 wherein said tem- 35
perature is from to about 290· C. to about 350· C.
12. A process according to claim 1 wherein said pressure
is from about 1000 psi to about 2400 psi.
13. A process according to claim 1 further comprising
regenerating copper reduced in the process to copper 40
(II) oxide and recycling said copper (II) oxide.
8
14. A process for treating a liquid feed stream containing
toxic materials comprising:
(a) contacting said feed stream with copper (II) oxide
as the only external source of oxygen; and
(b) flowing said copper (II) oxide-loaded stream into
the downcomer portion of a vertical tube reactor
system at a temperature of from about 70· C. to
about 370· C. and a pressure of from about 400 psi
to about 3200 psi, wherein said pressure is produced
by the hydrostatic head pressure inherent
from the downflowing mixture and for a time sufficient
to substantially detoxify said toxic materials
such that said feed stream is substantially free of
said toxic materials.
15. A process according to claim 14 wherein said
toxic materials are cyanides.
16. A process according to claim 14 wherein said
toxic materials are hydrocarbons.
17. A process according to claim 14 wherein said
toxic materials are halogenated hydrocarbons.
18. A process according to claim 17 wherein said
hydorcarbon is pentachlorophenol.
19. A process according to claim 14 wherein said
toxic materials are phenolic compounds.
20. A process according to claim 14 wherein said
toxic materials are dioxins.
21. A process according to claim 14 wherein said feed
stream is aqueous.
22. A process according to claim 14 wherein said feed
stream is non-aqueous.
23. A process according to claim 15 wherein said
copper (II) oxide is in at least a stoichiometric amount
necessary to oxidize said toxic materials.
24. A process according to claim 14 wherein said
temperature is from about 290· C. to about 350· C.
25. A process according to claim 14 wherein said
pressure is from 1000 psi to about 2400 psi.
26. A process according to claim 14 further comprising
regenerating copper reduced in the process to copper
(II) oxide and recycling said copper (II) oxide.
* * * * *
45
50
55
60
65
UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
PATENT NO.
DATED
INVENTOR(S)
4,582,613
April 15, 1986
Kenney et ale
It is certified that error appears in the above-identified patent and that said Letters Patent
is hereby corrected as shown below:
At Column 3, formula (i), line 61, that portion of the
formula reading "6C020 + 3H2" should read -- 6C02 + 3H20 --.
At Column 7, Claim 11, line 36, the word "to" after the
word "from" should be deleted.
At Column 8, Claim 18, line 22, the word "hydorcarbon"
should read -- halogenated hydrocarbon --.
Signed and Sealed this
Fourteenth Day of October, 1986
[SEAL]
Attest:
DONALD J. QUIGG
Attesting Officer CommissiOIler of Patents and Trademarks