U.S. patent application number 12/921579 was filed with the patent office on 2011-01-13 for method for removing mercury from hydrocarbon streams.
This patent application is currently assigned to BASF SE. Invention is credited to Michael Bender, Peter Rudolf.
Application Number | 20110005975 12/921579 |
Document ID | / |
Family ID | 40558912 |
Filed Date | 2011-01-13 |
United States Patent
Application |
20110005975 |
Kind Code |
A1 |
Rudolf; Peter ; et
al. |
January 13, 2011 |
METHOD FOR REMOVING MERCURY FROM HYDROCARBON STREAMS
Abstract
Method of removing mercury from a mercury-comprising hydrocarbon
stream, in which the hydrocarbon stream is brought into contact
with an absorbent comprising copper on a support material, wherein
the hydrocarbon stream is brought into contact with the absorbent
in the presence of hydrogen.
Inventors: |
Rudolf; Peter; (Ladenburg,
DE) ; Bender; Michael; (Jersey City, NJ) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ, LLP
P O BOX 2207
WILMINGTON
DE
19899
US
|
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
40558912 |
Appl. No.: |
12/921579 |
Filed: |
March 9, 2009 |
PCT Filed: |
March 9, 2009 |
PCT NO: |
PCT/EP09/52693 |
371 Date: |
September 9, 2010 |
Current U.S.
Class: |
208/253 |
Current CPC
Class: |
B01J 20/041 20130101;
B01J 20/3204 20130101; B01J 20/3234 20130101; B01J 20/3458
20130101; B01J 23/868 20130101; B01J 23/72 20130101; B01J 20/08
20130101; B01J 20/103 20130101; B01J 20/0237 20130101; B01D
2257/602 20130101; B01D 2251/202 20130101; B01D 2253/112 20130101;
C10G 25/003 20130101; C10G 45/02 20130101; B01J 20/3483 20130101;
B01J 20/3236 20130101; B01J 20/06 20130101; B01J 2220/56
20130101 |
Class at
Publication: |
208/253 |
International
Class: |
C10G 29/04 20060101
C10G029/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2008 |
EP |
08152517.2 |
Claims
1.-8. (canceled)
9. A method of removing mercury from a mercury-comprising
hydrocarbon stream, which comprises bringing a hydrocarbon stream
into contact with an absorbent comprising copper on a support
material, wherein the hydrocarbon stream is brought into contact
with the absorbent in the presence of hydrogen, wherein the
absorbent comprises from 10 to 60% by weight of copper oxide, from
0 to 40% by weight of zinc oxide, from 0 to 20% by weight of
aluminum oxide, from 5 to 25% by weight of magnesium oxide, from 10
to 40% by weight of silicon dioxide, from 0 to 5% by weight of
chromium(III) oxide and from 0 to 10% by weight of barium
oxide.
10. The method according to claim 9, wherein copper is present on a
porous oxidic support material.
11. The method according to claim 9, wherein the absorbent
comprises from 10 to 60% by weight of copper.
12. The method according to claim 9, wherein the hydrocarbon stream
is present in liquid form.
13. The method according to claim 9, wherein the absorbent is
present as a fixed bed.
14. The method according to claim 13, wherein the hydrocarbon
stream is brought into contact with the absorbent in the upflow
mode or the downflow mode.
15. The method according to claim 12, wherein the absorbent is
present in suspension in the hydrocarbon stream.
Description
[0001] The invention relates to a method of removing mercury and/or
arsenic from a mercury-comprising hydrocarbon stream.
[0002] Mercury is present as impurity in numerous streams of
materials which are obtained or processed in the chemical or
petrochemical industry. These are often streams which are obtained
in the processing or thermal utilization of fossil raw materials
such as petroleum, natural gas or coal and in the utilization of
wastes, since these raw materials or wastes comprise traces of
mercury in elemental form or in chemically bound form. Streams
comprising mercury as impurity are also obtained in processes in
which mercury or mercury-comprising substances are used as reagent
or catalyst. An example which may be mentioned is the electrolysis
hydrogen obtained in the production of chlorine by the amalgam
process. Because of the high toxicity of mercury, it is in most
cases necessary to separate off this metal or compounds comprising
this metal from the streams obtained in the processes concerned.
Furthermore, mercury has the property of attacking apparatuses
comprising aluminum by amalgam formation with destruction of the
oxide layer on the surface of the aluminum, so that streams which
pass through apparatuses or vessels made of aluminum have to be
virtually mercury-free. In addition, catalysts comprising noble
metals, as are used, for example, in petrochemical processes, are
poisoned by traces of mercury.
[0003] In Fuel Processing Technology 82 (2003), pp. 89-165, J. H.
Pavlish et al. give an overview of methods of removing mercury from
the offgas streams obtained in coal-fired power stations. In
Hydrocarbon Processing, 1999, p. 61 ff., S. M. Wilhelm gives an
overview of methods of removing mercury from liquid hydrocarbon
streams. An overview of the removal of mercury in olefin plants is
given by Steve Coleman et al.: Feedstock Contaminants in Ethylene
Plants, 2005 Spring National Meeting Atlanta, Ga., Apr. 10-14,
2005.
[0004] If metallic mercury is present in liquid form in streams of
materials, the mercury is frequently removed by mechanical measures
which exploit the high surface tension or the high specific gravity
of mercury by decantation, by means of coalescence filters,
activated carbon coated filters or the like. EP-A 0 761 830
discloses a simple, purely mechanical method in which finely
divided mercury is collected by coalescence to form larger droplets
of mercury which are easy to separate off. WO 2004/048624 describes
a method of removing mercury by filtration through
electrographite.
[0005] The removal of mercury is often also carried out using
methods in which the mercury is bound to an adsorbent. Thus, DE-A
26 43 478 describes the separation of mercury from liquids by
adsorption on activated carbon having a specific surface area of at
least 250 m.sup.2/g. Carbon-based adsorbents are used, inter alia,
for the removal of mercury from streams of materials, as described
in U.S. Pat. No. 3,755,989. U.S. Pat. No. 4,500,327 describes
sulfur-impregnated activated carbon for removing mercury from
gaseous streams, while JP 52-53793 describes the use of
iodide-comprising activated carbon for removing mercury from liquid
streams. U.S. Pat. No. 4,909,926 and U.S. Pat. No. 4,094,777
describe the use of active compositions comprising CuS or CuO or
Ag.sub.2S on support materials such as aluminum oxide for removing
mercury from streams of materials. EP-A 0 385 742 describes a
process for removing mercury from liquid hydrocarbon streams
comprising hydrocarbons having up to 8 carbon atoms by bringing the
streams into contact with metallic copper or copper compounds
present on a support.
[0006] The formation of solid amalgams is also often used for the
removal of mercury. The most suitable metals for this purpose are
the metals of group XI of the Periodic Table (Cu, Ag, Au), which
are usually used in the form of an absorption composition in which
the metal is finely distributed on a support. Thus, DE-A 21 02 039
discloses a process for removing mercury from gases, in which the
mercury-comprising gases are brought into contact with a
composition comprising copper on a porous aluminum oxide support.
U.S. Pat. No. 4,230,486 discloses a process for removing mercury
from liquids by passing the liquids over an absorbent comprising
metallic silver on a porous support such as activated carbon or a
ceramic support. DE-A 42 21 207 teaches a process for removing
mercury from alkaline metal hydroxide solution or alkaline metal
alkoxide solution by passing the solutions over silver-coated
fibers. DE-A 41 16 890 discloses absorbents for removing mercury,
which comprise, in particular, Cu, Ag, Fe and Bi, or else Au, Sn,
Zn and Pd and also mixtures of the metals mentioned in metallic or
oxidic or sulfidic form on an activated carbon support having a BET
surface area of from 300 to 1000 m.sup.2/g.
[0007] U.S. Pat. No. 4,911,825 describes the removal of mercury and
arsenic from hydrocarbon streams by bringing these into contact
with a catalyst comprising nickel and palladium on aluminum oxide
in the presence of hydrogen in a first step and into contact with
an absorbent comprising sulfur or a metal sulfide, preferably
copper sulfide or a combination of copper sulfide and silver
sulfide, on a support in a second step. The process can also be
carried out in a single stage over a mixture of the catalyst and
the absorbent. FR-A 2 310 795 describes the removal of mercury from
a gaseous natural gas stream using an absorbent comprising metallic
gold, silver, copper or nickel on a support composed of silicon
dioxide, aluminum oxide or an aluminosilicate having a BET surface
area of from 40 to 250 m.sup.2/g. WO 91/15559 discloses a method of
removing mercury from liquid hydrocarbon streams by bringing them
into contact with an absorbent produced by mixing of a pulverulent
oxide, preferably an oxide selected from among nickel oxide, copper
oxide and cobalt oxide, with a porous support material such as
aluminum oxide, silicon dioxide, zeolites or clays and subsequent
reduction.
[0008] It is an object of the invention to provide an improved
method of removing mercury from a mercury-comprising hydrocarbon
stream.
[0009] This object is achieved by a method of removing mercury from
a mercury-comprising hydrocarbon stream, in which the hydrocarbon
stream is brought into contact with an absorbent comprising copper
on a porous oxidic support material, wherein the hydrocarbon stream
is brought into contact with the absorbent in the presence of
hydrogen.
[0010] It has been found that a very much better removal of mercury
from the hydrocarbon streams is achieved in the presence of
hydrogen using copper-comprising absorbents which comprise copper
on a support and are effective as hydrogenation catalysts than in
the absence of hydrogen.
[0011] The absorbent used according to the invention comprises
copper, preferably in reduced form, on a porous support material.
The absorbent used according to the invention is effective as
hydrogenation catalyst. Suitable porous support materials are
amorphous and crystalline aluminosilicates, aluminum oxide, silicon
dioxide, clays and metal oxides. Suitable clays are, for example,
attapulgite, kaolin, bentonite, Fuller's earth. Suitable metal
oxides are, for example, aluminum oxides and silicon dioxide and
also magnesium oxide, zirconium dioxide, titanium dioxide, zinc
oxide, chromium(III) oxide, barium oxide and mixtures thereof. A
preferred aluminum oxide is .gamma.-aluminum oxide.
[0012] It is possible to use all customary copper-comprising
hydrogenation catalysts in activated (reduced) form in the method
of the invention.
[0013] The copper comprising hydrogenation-active absorbents used
according to the invention can be obtained by mixing of copper
oxide with a support material and subsequent conversion of copper
into the metallic form by reduction, preferably in a stream of
hydrogen. The absorbents used according to the invention can also
be produced by impregnation of the support material with an aqueous
solution of a copper salt, drying, if appropriate calcination and
conversion of the copper into the metallic form by reduction,
preferably by means of a hydrogen-comprising gas stream, although
it is also possible to use a reducing agent such as hydrazine.
[0014] In the absorbent used according to the invention, copper is
generally present in reduced, i.e. metallic (elemental), form
finely dispersed on the support material. In general, the
absorbents used according to the invention comprise from 10 to 50%
by weight of copper on an oxidic support material. Examples of
suitable compositions on the basis of which the absorbents used
according to the invention are obtained are compositions comprising
copper oxide, zinc oxide and aluminum oxide or compositions
comprising copper oxide, magnesium oxide, barium oxide,
chromium(III) oxide, zinc oxide and silicon dioxide. Particular
preference is given to a mixture of from 10 to 60% by weight of
copper oxide, from 0 to 40% by weight of zinc oxide, from 0 to 20%
by weight of aluminum oxide, from 5 to 25% by weight of magnesium
oxide, from 10 to 40% by weight of silicon dioxide, from 0 to 5% by
weight of chromium(III) oxide and from 0 to 10% by weight of barium
oxide.
[0015] Hydrocarbon streams from which mercury can be removed
according to the invention are any hydrocarbon streams which can be
contaminated with mercury. These generally comprise aliphatic,
aromatic, alicyclic and/or heterocyclic hydrocarbons having from 1
to 14 carbon atoms. Examples of hydrocarbon mixtures which can be
freed of mercury according to the invention are LNG (liquefied
natural gas), LPG (liquefied petroleum gas), naphtha and kerosene.
Examples of pure hydrocarbons which can be purified according to
the invention are ethylene and propylene and also aliphatic
hydrocarbons.
[0016] The mercury content of the hydrocarbons or hydrocarbon
mixtures before carrying out the method of the invention can be up
to 100 ppm, but is generally up to 1 ppm of Hg. Mercury is
generally present in the form of organomercury compounds.
[0017] The method of the invention can be carried out in the
suspension mode or the fixed-bed mode. If it is carried out in the
fixed-bed mode, it can be carried out in the upflow or downflow
mode. The hydrocarbons or hydrocarbon mixtures comprising mercury
or arsenic can be used in gaseous or liquid form. The hydrocarbons
or hydrocarbon mixtures are preferably used in liquid form.
Hydrogen is introduced together with the gaseous or liquid
hydrocarbon or hydrocarbon mixture into a suitable reaction vessel
and passed, generally in cocurrent, over the particulate absorbent
present in a fixed bed. This can be carried out in the upflow or
downflow mode. However, hydrogen and hydrocarbon or hydrocarbon
mixture can also be passed over the bed of absorbent in
countercurrent. The absorbent can also be present in suspension in
the hydrocarbon or hydrocarbon mixture. In general, the method is
carried out at a temperature of from 30 to 250.degree. C.,
preferably from 60 to 180.degree. C., and a hydrogen pressure of
from 1 to 20 bar. The pressure is preferably selected so that the
hydrocarbon or the hydrocarbon mixture is present as a liquid. The
amount of hydrogen introduced generally corresponds to a space
velocity of from 10 to 650 standard I per kg of absorbent and
hour.
[0018] After the absorbent is exhausted, it can be thermally
regenerated by heating it in a stream of inert gas or a
hydrogen-comprising gas stream, in general at temperatures of from
180 to 400.degree. C., for example from 200 to 220.degree. C., and
condensing out vaporized mercury.
[0019] The invention is illustrated by the following examples.
EXAMPLES
Comparative Example 1
[0020] A solution of diphenylmercury (Ph.sub.2Hg) in 500 ml of
octane, corresponding to 350 ppm of Hg, was heated to 60.degree. C.
in a glass flask. 1.5 standard I/h of hydrogen were passed into
this solution while stirring. 5 g of an unreduced hydrogenation
catalyst comprising 40% by weight of CuO, 40% by weight of ZnO and
20% by weight of Al.sub.2O.sub.3 in the form of 3.times.5 mm
pellets (absorbent A) were added to this solution. Samples were
taken from the solution after 2 h and 24 h and the mercury content
of the samples was determined. The results are shown in table
1.
Comparative Example 2
[0021] A solution of diphenylmercury in 500 ml of octane,
corresponding to 350 ppm of mercury, was heated to 60.degree. C. in
a glass flask. 5 g of the catalyst comprising 40% by weight of CuO,
40% by weight of ZnO and 20% by weight of Al.sub.2O.sub.3 which had
previously been reduced and activated by means of H.sub.2 at
180.degree. C. (absorbent B) in the form of 3.times.5 mm pellets
were added to this solution. Hydrogen was not passed in. The
solution was stirred. Samples were taken after 2 h and 24 h and
their mercury content was determined. The results are shown in
table 1.
Example 1
[0022] The procedure of comparative example 2 was repeated, but 1.5
standard I/h of hydrogen were passed in. Samples were taken at
regular intervals and their mercury content was determined. The
results are shown in table 1.
Example 2
[0023] The procedure of example 1 was repeated, but the reduced
catalyst was added in pulverulent form (absorbent C). Samples were
taken at regular intervals and their mercury content was
determined. The results are shown in table 1.
TABLE-US-00001 TABLE 1 Comp. Ex. 1 Comp. Ex. 2 Example 1 Example 2
Time [h] Hg [ppm] Hg [ppm] Hg [ppm] Hg [ppm] 0 350 350 350 350 1 --
270 250 205 2 310 -- 150 115 3 -- -- 120 75 4 -- -- -- 60 5 -- --
72 45 6 -- 145 51 15 7 -- -- 37 -- 8 -- -- 28 -- 21 0.3 22 0.3 24
135 47 0.8 0.3
Example 3
[0024] The procedure of example 1 was repeated, but the solution
was maintained at 25.degree. C. Samples were taken at regular
intervals and their mercury content was determined. The results are
shown in table 2.
Example 4
[0025] The procedure of example 1 was repeated. The temperature was
thus 60.degree. C. Samples were taken at regular intervals and
their mercury content was determined. The results are shown in
table 2.
Example 5
[0026] The procedure of example 1 was repeated, but the solution
was heated to 100.degree. C. Samples were taken at regular
intervals and their mercury content was determined. The results are
shown in table 2.
TABLE-US-00002 TABLE 2 Example 3 Example 4 Example 5 (25.degree.
C.) (60.degree. C.) (100.degree. C.) Time [h] Hg [ppm] Hg [ppm] Hg
[ppm] 0 350 350 350 1 300 250 90 2 290 150 -- 3 250 120 30 4 240 --
-- 5 220 72 -- 6 205 51 2.3 7 -- 37 -- 8 -- 28 -- 22 80 -- -- 24 75
0.8 0.14 93 4.6 -- --
Example 6
[0027] The experiments were carried out in a monoline reactor
having an internal diameter of 6 mm and a total length of 5 m. The
reactor comprised 4 segments connected to one another by means of a
capillary. The reactor was operated in the downflow mode. The
reactor segments were maintained at 60.degree. C. The liquid
hydrocarbon feed was mixed with hydrogen before the reactor inlet.
The reactor output was cooled by means of a low-temperature
condenser and the gas phase was separated from the liquid phase.
The liquid phase was employed for determining the mercury content
and the gas phase was disposed of via a mercury guard bed.
[0028] 80 g of a catalyst comprising 45% by weight of CuO, 16% by
weight of MgO, 35% by weight of SiO.sub.2, 0.9% by weight of
Cr.sub.2O.sub.3, 1.1% by weight of BaO and 0.6% by weight of ZnO in
the form of 3.times.5 mm pellets were present in the reactor. A
glass sphere having a diameter of 2 mm was present between each of
the individual pellets. The catalyst was firstly activated in a
stream of hydrogen at from 180 to 220.degree. C. The reactor was
subsequently cooled to 60.degree. C. in a stream of hydrogen. The
reactor was operated at atmospheric pressure.
[0029] Octane which had been saturated over an organomercury
compound was used as feed. In part of the experiments,
phenylmercury acetate PhHgOAc was used as organomercury compound,
and in another part of the experiments mercury acetate
Hg(OAc).sub.2 was used as organomercury compound. A number of
batches having different mercury concentrations were used in each
case. 100 standard I/h of the mercury-comprising octane and 2
standard I/h of hydrogen were metered in. The results of the
experiments are summarized in table 3.
TABLE-US-00003 TABLE 3 Experiment Hg compound Hg concentration Hg
concentration in the No. added in the feed [ppm] output [ppm] 1
PhHgOAc 80 0.004 2 PhHgOAc 90 0.002 3 PhHgOAc 80 0.004 4 PhHgOAc 60
0.001 5 Hg(OAc).sub.2 6 0.001 6 Hg(OAc).sub.2 1.4 0.001 7
Hg(OAc).sub.2 0.6 0.001 8 Hg(OAc).sub.2 2.8 0.001 9 Hg(OAc).sub.2
1.2 0.001 10 PhHgOAc 90 0.001 11 PhHgOAc 120 0.003 12 PhHgOAc 75
0.004
* * * * *