Note: Descriptions are shown in the official language in which they were submitted.
87029318
TITLE
ABSORBENT AND METHOD FOR PREPARING THE SAME
CROSS REFERENCE TO RELATED APPLICATIONS
100011 This Application claims priority of Taiwan Patent Application No.
108147339,
filed on December 24, 2019.
TECHNICAL FIELD
[0002] The disclosure relates to an absorbent, and in particular it relates
to an
absorbent prepared from metal-smelting by-products.
BACKGROUND
[0003] Hydrogen sulfide (H2S) gas is a colorless gas with the smell of
rotten eggs. It
has high toxicity, corrosivity and flammability. When the concentration
reaches 5ppm, it
causes irritation to the eyes, nose, and throat, and when the concentration
exceeds
1,000ppm, it can be fatal. Hydrogen sulfide (H2S) gas exists in various
hydrocarbon sources,
such as natural gas, biogas, syngas, and even landfills. Depending on the end
use, there are
strict limits on the content of hydrogen sulfide (H2S) gas in feed gas.
[0004] Based on the cost, efficiency and toxicity of the absorbent, metal
oxides such as
zinc oxide (Zn0), calcium oxide (CaO) and iron oxide (Fe2O3) are the most
commonly
used absorbents. However, in a high-temperature (greater than 600 C) reducing
atmosphere,
zinc oxide (ZnO) is easily reduced to metallic zinc (Zn), which escapes in the
form of high-
temperature gaseous metal smoke, resulting in a loss of absorbent.
[0005] Therefore, development of an absorbent that has a high absorption
rate for
hydrogen sulfide (H2S) gas and that can take thermal stability into account is
expected.
SUMMARY
[0006] In order to effectively increase the absorption rate for hydrogen
sulfide (H2S)
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gas of absorbents, the disclosure provides an absorbent, by a co-precipitation
method, the
industrial by-product raw materials are recombined to form zinc ferrite
(ZnFe204) and
calcium ferrite (CaFe204) with a spine! structure to increase the specific
surface area and
pore volume of the absorbent.
[0007] In accordance with one embodiment of the disclosure, an absorbent is
provided.
The absorbent includes: calcium ferrite (CaFe204), zinc ferrite (ZnFe204), or
a combination
thereof, wherein the molar ratio of calcium to iron in the absorbent is
between 0.1:1 and 1:1,
and the molar ratio of zinc to iron in the absorbent is between 0.1:1 and 1:1.
[0008] In accordance with one embodiment of the disclosure, a method for
preparing
an absorbent is provided. The method includes: mixing a metal-smelting by-
product with
an acidic solvent to form a first solution, wherein the metal-smelting by-
product includes
iron, calcium, zinc, or a combination thereof; adding an iron-containing
solution to the first
solution to adjust the molar ratio of calcium to iron or zinc to iron in the
first solution,
wherein the molar ratio of calcium to iron in the first solution is between
0.1:1 and 1:1, and
the molar ratio of zinc to iron in the first solution is between 0.1:1 and
1:1; adding an
alkaline solvent to the first solution to perform a co-precipitation process
to form a salt
solution; performing a filtration process on the salt solution to obtain a
solid filter; and
performing a calcination process on the solid filter to prepare an absorbent,
wherein the
absorbent includes calcium ferrite (CaFe204), zinc ferrite (ZnFe204), or a
combination
thereof
[0009]
[0010] A detailed description is given in the following embodiments with
reference to
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure can be more fully understood by reading the subsequent detailed
description
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87209318
and examples with references made to the accompanying drawings, wherein:
[0011] FIG. 1 shows an SEM photograph (magnification of 5,000 times) of an
absorbent (converted from slag) in accordance with one embodiment of the
disclosure;
[0012] FIG. 2 shows an SEM photograph (magnification of 5,000 times) of an
absorbent (converted from dust) in accordance with one embodiment of the
disclosure;
[0013] FIG. 3 shows an SEM photograph (magnification of 5,000 times) of a
slag
absorbent;
[0014] FIG. 4 shows an SEM photograph (magnification of 5,000 times) of a
dust
absorbent;
[0015] FIG. 5 shows the absorption effect of an absorbent on hydrogen
sulfide (H2S)
gas in accordance with one embodiment of the disclosure;
[0016] FIG. 6 shows a thermogravimetric analysis chart of an absorbent
(converted
from slag) in accordance with one embodiment of the disclosure;
[0017] FIG. 7 shows a thermogravimetric analysis chart of an absorbent
(converted
from dust) in accordance with one embodiment of the disclosure;
[0018] FIG. 8 shows a thermogravimetric analysis chart of a slag absorbent;
and
[0019] FIG. 9 shows a thermogravimetric analysis chart of a dust absorbent.
DETAILED DESCRIPTION
[0020] The following description is of the best-contemplated mode of
carrying out the
disclosure. This description is made for the purpose of illustrating the
general principles of
the disclosure and should not be taken in a limiting sense.
[0021] In accordance with one embodiment of the disclosure, an absorbent is
provided.
The absorbent includes calcium ferrite (CaFe204), zinc ferrite (ZnFe204), or a
combination
thereof The molar ratio of calcium to iron in the absorbent is between about
0.1:1 and
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about 1:1. The molar ratio of zinc to iron in the absorbent is between about
0.1:1 and about
1:1.
[0022] In one embodiment, the calcium ferrite (CaFe204) and the zinc
ferrite (ZnFe204)
may include a spinel structure.
[0023] In one embodiment, the absorbent further includes, for example,
magnesium
oxide (MgO), aluminum oxide (Al2O3), silicon oxide (SiO2), sulfur oxide (SO3),
calcium
oxide (CaO), manganese oxide (MnO), iron oxide (Fe2O3), zinc oxide (Zn0), or a
combination thereof In one embodiment, the magnesium oxide (MgO) is about 0-5
parts
by weight, the aluminum oxide (A1203) is about 0-4 parts by weight, the
silicon oxide (SiO2)
is about 0-20 parts by weight, the sulfur oxide (SO3) is about 0-3 parts by
weight, the
calcium oxide (CaO) is about 1-25 parts by weight, the manganese oxide (MnO)
is about I-
parts by weight, the iron oxide (Fe2O3) is about 25-75 parts by weight, and
the zinc oxide
(ZnO) is about 1-40 parts by weight, based on 100 parts by weight of the
absorbent.
[0024] In one embodiment, the calcium ferrite (CaFe204) has a
characteristic peak
value of 20=33.64 , 33.57 and 61.41 . In one embodiment, the zinc ferrite
(ZnFe204) has a
characteristic peak value of 20=29.92 , 36.92 and 62.24 .
[0025] In one embodiment, the absorbent has a specific surface area of
about 1-80m2/g.
In one embodiment, the absorbent has a pore volume of about 0.01-0.5cm3/g.
[0026] In accordance with one embodiment of the disclosure, the composition
of the
metal-smelting by-products meets the following condition (S-0) or condition (D-
0).
[0027] Slag (S-0): 0.1wt% to 3wt% of magnesium oxide, 1 wt% to 6wt% of
aluminum
oxide, 12wt% to 25wt% of silicon oxide, 0.1wt% to 3wt% of sulfur oxide, 15wt%
to
25wt% of calcium oxide, lwt% to 6wt% of manganese oxide, 25wt% to 50wt% of
iron
oxide, and 2wt% to 8wt% of zinc oxide, based on the total weight of the
absorbent; and
dust (D-0): 0.1wt% to 3wt% of magnesium oxide, 0.1wt% to 3wt% of aluminum
oxide,
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lwt% to lOwt% of silicon oxide, 0.1wt% to 4wt% of sulfur oxide, lwt% to 15wt%
of
calcium oxide, lwt% to 5wt% of manganese oxide, 35wt% to 60wt% of iron oxide,
and
20wt% to 40wt% of zinc oxide, based on the total weight of the absorbent.
[0028] In accordance with one embodiment of the disclosure, before
adjusting
composition, the metal-smelting by-product (slag (S-0)) has a specific surface
area between
0.1m2/g and 5m2/g and a pore volume between 0.01cm3/g and 0.2cm3/g; the metal-
smelting
by-product (dust (D-0)) has a specific surface area between 0.1m2/g and 5m2/g
and a pore
volume between 0.01cm3/g and 0.2cm3/g.
[0029] In accordance with one embodiment of the disclosure, the composition
of the
metal-smelting by-product meets the condition(slag (S-0)), and the weight
ratio of the iron
ions in the iron-containing compound (such as ferric chloride) to the metal-
smelting by-
product is 1:10 to 1:5 (for example, 1:9, 1:8, 1:7 or 1:6). In addition, the
composition of the
metal-smelting by-product meets the condition (dust (D-0)), and the weight
ratio of the
iron ions in the iron-containing compound to the metal-smelting by-product is
1:20 to 1:10
(for example, 1:19, 1:18, 1:17, 1:16, 1:15, 1:14, 1:13, 1:12 or 1:11).
[0030] In accordance with one embodiment of the disclosure, a method for
preparing
an absorbent is provided. The method includes the following steps. First, a
metal-smelting
by-product and an acidic solvent are mixed to form a first solution. The metal-
smelting by-
product includes iron, calcium, zinc, or a combination thereof In one
embodiment, the first
solution is weakly acidic, and its pH value is, for example, 5-6.
[0031] Next, an iron-containing solution is added to the first solution to
adjust the
molar ratio of calcium to iron or zinc to iron in the first solution. Since
the main
components and ratios of metal-smelting by-products generally obtained are
diverse (the
ratio of calcium to iron or zinc to iron is different), the disclosure adjusts
the molar ratio of
calcium to iron or zinc to iron in the first solution by adding the iron-
containing solution to
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fall within the applicable range of the disclosure. In one embodiment, the
molar ratio of
calcium to iron in the first solution is between about 0.1:1 and about 1:1. In
one
embodiment, the molar ratio of zinc to iron in the first solution is between
about 0.1:1 and
about 1:1. Next, an alkaline solvent is added to the first solution to perform
a co-
precipitation process to form a salt solution. In one embodiment, the salt
solution is weakly
alkaline, and its pH value is, for example, greater than or equal to 7.
[0032] Next, a filtration process is performed on the salt solution to
obtain a solid filter.
Next, a calcination process is performed on the solid filter to prepare an
absorbent. The
absorbent includes calcium ferrite (CaFe204), zinc ferrite (ZnFe204), or a
combination
thereof The calcium ferrite (CaFe204) has a characteristic peak value of
20=33.64 , 33.57
and 61.41 . The zinc ferrite (ZnFe204) has a characteristic peak value of
20=29.92 , 36.92
and 62.24 .
[0033] In one embodiment, the metal-smelting by-product may include slag or
dust. In
one embodiment, the iron in the iron-containing solution may include ferric
chloride, ferric
sulfate, ferric nitrate, ferric phosphate, ferric citrate, ferric oxalate, or
ferric carbonate. In
one embodiment, the acidic solvent may include hydrochloric acid, sulfuric
acid, nitric acid,
phosphoric acid, citric acid, oxalic acid, or carbonic acid. In one
embodiment, the alkaline
solvent may include sodium hydroxide, potassium hydroxide, sodium carbonate,
potassium
carbonate, or ammonia. In one embodiment, the calcination process has an
operation
temperature that is lower than about 300 C.
[0034] The absorbent of the present disclosure can be applied to reduce the
concentration of hydrogen sulfide (H2S) gas in the syngas to avoid the sulfur-
containing
substances in the syngas causing corrosion of the delivery pipeline/equipment
and
poisoning of the downstream catalyst bed. The syngas may include, for example,
gas
produced by gasification of coal, waste, or biomass.
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[0035] The present disclosure recombines iron oxide (Fe2O3) and zinc oxide
(ZnO) in
industrial by-products (i.e. metal-smelting by-products, such as slag or dust)
by a co-
precipitation method to form zinc ferrite (ZnFe204) with a spinel structure,
and recombines
iron oxide (Fe2O3) and calcium oxide (CaO) to form calcium ferrite (CaFe204)
with a spinel
structure. In addition to enhancing the thermal stability and mechanical
properties of the
absorbent, the recombined compound also has a higher specific surface area and
pore
volume than the raw material, which contributes to increase the contact area
of the
absorbent with hydrogen sulfide (H2S) gas, and increase the absorption rate of
the
absorbent for hydrogen sulfide (H2S) gas and the utilization rate of the
absorbent. The
present disclosure can be applied to the field of gas purification technology,
enhance the
application value of such industrial by-products, achieve the purpose of new
energy
development and resource reuse, and construct a complete circular economy
system.
[0036] Examples/Comparative Examples
[0037] Example 1
[0038] Preparation of the absorbent (converted from slag)
[0039] First, 100g of slag (a metal-smelting by-product, provided or
manufactured by
Taiwan Steel Union Co., Ltd.) and 180g of 36% hydrochloric acid (an acidic
solvent) were
mixed and stirred. After filtration, a filtrate was obtained. The main
components of the slag
included 39.6 parts by weight of iron oxide (Fe2O3), 19.4 parts by weight of
calcium oxide
(CaO), and 19.3 parts by weight of silicon oxide (SiO2) (based on 100 parts by
weight of
the slag). After that, 100g of 35% ferric chloride aqueous solution was added
to the filtrate
to adjust the molar ratio of calcium to iron in the filtrate to about 1:2.
Next, 200g of 35%
sodium hydroxide aqueous solution (an alkaline solvent) (a precipitating
agent) was added
to the filtrate to perform a co-precipitation process to form a salt solution.
After that, a
filtration process was performed on the salt solution to obtain 75g of solid
filtrate. Next, a
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calcination process with a temperature of about 300 C was performed on the
solid filter for
about 8 hours, and the absorbent (S-1) of this embodiment was prepared. After
that, the
chemical composition and physicochemical properties (such as specific surface
area and
pore volume) of the absorbent were analyzed. The analysis results are shown in
Table 1
below. The prepared absorbent was photographed by SEM (magnification was 5,000
times),
as shown in FIG. 1, to observe the microstructure of the absorbent. In
accordance with the
X-ray diffraction spectrum of the absorber in this embodiment, its main
component was
calcium ferrite (CaFe204), and the characteristic peak value thereof was
20=33.64 , 33.57
and 61.41 . It can be seen that through the process described in Example 1,
the slag has
been recombined to form a spinel structure, and the mechanical properties of
the absorbent
have also been improved.
[0040] Example 2
[0041] Preparation of the absorbent (converted from dust)
[0042] First, 100g of dust (a metal-smelting by-product) and 150g of 35%
hydrochloric
acid (an acidic solvent) were mixed and stirred. After filtration, a filtrate
was obtained. The
main components of the dust included 53.0 parts by weight of iron oxide
(Fe2O3) and 32.1
parts by weight of zinc oxide (ZnO) (based on 100 parts by weight of the
dust). After that,
65g of 35% ferric chloride aqueous solution was added to the filtrate to
adjust the molar
ratio of zinc to iron in the filtrate to about 1:2. Next, 75g of 35% sodium
hydroxide aqueous
solution (an alkaline solvent) (a precipitating agent) was added to the
filtrate to perform a
co-precipitation process to form a salt solution. After that, a filtration
process was
performed on the salt solution to obtain 95g of solid filtrate. Next, a
calcination process
with a temperature of about 300 C was performed on the solid filter for about
8 hours, and
the absorbent (D-1) of this embodiment was prepared. After that, the chemical
composition
and physicochemical properties (such as specific surface area and pore volume)
of the
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absorbent were analyzed. The analysis results are shown in Table 1 below. The
prepared
absorbent was photographed by SEM (magnification was 5,000 times), as shown in
FIG. 2,
to observe the microstructure of the absorbent. In accordance with the X-ray
diffraction
spectrum of the absorber in this embodiment, its main component was zinc
ferrite
(ZnFe204), and the characteristic peak value thereof was 20=29.92 , 36.92 and
62.24 . It
can be seen that through the process described in Example 2, the dust has been
recombined
to form a spinel structure, and the mechanical properties of the absorbent
have also been
improved.
[0043] Comparative Example 1
[0044] Analysis of the chemical composition and physicochemical properties
of
the slag absorbent
[0045] The chemical composition and physicochemical properties (such as
specific
surface area and pore volume) of the provided slag absorbent (S-0) were
analyzed. The
analysis results are shown in Table 1 below. The slag absorbent was
photographed by SEM
(magnification was 5,000 times), as shown in FIG. 3, to observe the
microstructure of the
slag absorbent.
[0046] Comparative Example 2
[0047] Analysis of the chemical composition and physicochemical properties
of
the dust absorbent
[0048] The chemical composition and physicochemical properties (such as
specific
surface area and pore volume) of the provided dust absorbent (D-0) were
analyzed. The
analysis results are shown in Table 1 below. The dust absorbent was
photographed by SEM
(magnification was 5,000 times), as shown in FIG. 4, to observe the
microstructure of the
dust absorbent.
Table 1
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Examples/ Comparative Example 1 Comparative Example 2
Comparative Example 1 (S-1) Example 2 (D-1)
Examples (S-0) (D-0)
(Absorbent code)
Composition analysis (parts by weight)
MgO 0.7 0.5 1.0 0.6
A1203 3.2 0.8 0.4 0
5i02 19.3 0 3.5 0
SO3 2.3 0.5 2.2 0.4
CaO 19.4 23.8 3.6 1.0
MnO 3.8 2.1 2.2 1.6
Fe2O3 39.6 70.2 53.0 64.7
ZnO 6.7 2.1 32.1 31.7
Analysis of physicochemical properties
Specific surface 1.7 14.65 2.7 34.19
area (m2/g)
Pore volume 0.01 0.09 0.016 0.19
(cm3/g)
[0049] In Comparative Example 1, the main components of the slag absorbent
(No.: S-
O) were 39.6 parts by weight of iron oxide (Fe2O3), 19.4 parts by weight of
calcium oxide
(CaO), and 19.3 parts by weight of silicon oxide (SiO2). In Comparative
Example 2, the
main components of the dust absorbent (No.: D-0) were 53.0 parts by weight of
iron oxide
(Fe2O3) and 32.1 parts by weight of zinc oxide (Zn0). According to the
analysis results of
the physicochemical properties in Table 1, whether it is the slag absorbent (S-
0) of
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Comparative Example 1 or the dust absorbent (D-0) of Comparative Example 2, it
is a
material with low specific surface area and non-porous. In Example 1, the
molar ratio of
calcium to iron in the absorbent (S-1) converted from slag was about 0.48,
which was close
to 0.5. In Example 2, the molar ratio of zinc to iron in the absorbent (D-1)
converted from
dust was about 0.475, which was also close to 0.5, so it can be seen that the
products
prepared in Examples 1 and 2 were in line with the target products of calcium
ferrite
(CaFe204) and zinc ferrite (ZnFe204). Furthermore, according to the analysis
results of the
physicochemical properties of Table 1, the specific surface area and pore
volume of the
calcium ferrite (CaFe204) absorbent (S-1) of Example 1 and the zinc ferrite
(ZnFe204)
absorbent (D-1) of Example 2 are significantly higher than their raw materials
(slag or dust),
which indicates that the surface properties of the absorbent prepared by the
methods of
Examples 1 and 2 can thus be effectively improved, beneficial to improvement
of
absorption efficiency.
[0050] In
addition, according to the SEM microstructure photos (magnification of
5,000 times) of FIGS. 1 to 4 (the absorbents S-1, D-1, S-0 and D-0), it can be
seen from the
appearance that the surface of the slag absorbent (S-0) (as shown in FIG. 3)
and the dust
absorbent (D-0) (as shown in FIG. 4) are smooth and free of pores. However,
the surface of
the absorbent (S-1) converted from slag (as shown in FIG. 1) of Example 1 is
composed of
a large number of spherical particles with a particle diameter of less than
100nm, and there
are pores. In Example 2, the absorbent (D-1) converted from dust (as shown in
FIG. 2) is
composed of a foil-like substance, and the appearance is very different from
the dust raw
material. According to the comparison of the SEM microstructure photos in
FIGS. 1 to 4,
the analysis results shown in Table 1 that the specific surface area and pore
volume of the
absorbent of the present disclosure are significantly improved compared to the
surface
properties of its raw materials can be verified.
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[0051] Example 3
[0052] Test of absorption effect of the absorbent on hydrogen sulfide (H2S)
gas
[0053] The calcium ferrite (CaFe204) absorbent (S-1) prepared in Example 1,
the zinc
ferrite (ZnFe204) absorbent (D-1) prepared in Example 2, the slag absorbent (S-
0) provided
in Comparative Example 1 and the dust absorbent (D-0) provided in Comparative
Example
2 were selected for the test of the absorption effect of the absorbents on
hydrogen sulfide
(H25) gas. At 400 C, the inlet concentration of hydrogen sulfide (H25) gas was
set at 1,000
ppm, and the process was continuously performed for 30 hours. During the
period, the
reacted gas was collected according to the set time (sampling every 30
minutes, and 6
minutes per sampling), and the outlet concentration of hydrogen sulfide (H25)
gas was
detected using a hydrogen sulfide (H25) gas detection tube (Gastec Piston
Pump). The
relationship between the outlet concentration of hydrogen sulfide (H2S) gas
over time is
shown in FIG. 5.
[0054] It can be seen from FIG. 5 that after the calcium ferrite (CaFe204)
absorbent (S-
1) prepared in Example 1 and the zinc ferrite (ZnFe204) absorbent (D-1)
prepared in
Example 2 were operated for 7 hours, the measured outlet concentration of
hydrogen
sulfide (H2S) gas approached zero (less than 2ppm). At this time, the
absorption effect of
the absorbent (S-1) and the absorbent (D-1) on hydrogen sulfide (H25) gas is
obviously the
same as that of the slag absorbent (S-0) of Comparative Example 1 and the dust
absorbent
(D-0) of Comparative Example 2 on hydrogen sulfide (H25) gas. However, when
the
absorbent (S-1) and the absorbent (D-1) were continuously operated for 21
hours, the
measured outlet concentration of hydrogen sulfide (H25) gas was merely 200 ppm
and 120
ppm respectively, which is much lower than the results (about 1,000 ppm) of
the slag
absorbent (S-0) and the dust absorbent (D-0) after they were continuously
operated for 20
hours.
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[0055] It can be seen from the test results in FIG. 5 that the absorption
capacity (or
removal rate) for hydrogen sulfide (H2S) gas of the absorbent (S-1) and the
absorbent (D-1)
of the present disclosure is far superior to that of the slag absorbent (S-0)
and the dust
absorbent (D-0). After the reaction, the absorbent (S-1) and the absorbent (D-
1) were
collected and the sulfur content thereof was analyzed, it can be known that
the absorption
capacity (or removal rate) for hydrogen sulfide (H25) gas of the absorbent (S-
1) and the
absorbent (D-1) was 0.25g hydrogen sulfide/g absorbent and 0.31g hydrogen
sulfide/g
absorbent respectively, which is far superior to that of the slag absorbent (S-
0) and the dust
absorbent (D-0) for hydrogen sulfide (H25) gas (i.e. 0.14g hydrogen sulfide/g
absorbent and
0.18g hydrogen sulfide/g absorbent, respectively). This test result shows that
the absorbents
prepared by the methods of Example 1 and Example 2 have a specific surface
area superior
to that of its raw material, so the effective contact area between the active
material in the
absorbent and hydrogen sulfide (H25) gas is increased. In addition, the
reduction in the size
of the particles in the absorbent or the formation of a foil structure are
conducive to
improving the efficiency of the absorbent, and its ability to absorb hydrogen
sulfide (H25)
gas is significantly improved.
[0056] Example 4
[0057] Analysis of thermal stability of the absorbent
[0058] The calcium ferrite (CaFe204) absorbent (S-1) prepared in Example 1
was
selected for thermogravimetric analysis to evaluate its thermal stability.
With a
thermogravimetric analyzer (TGA), the test temperature was set to around 1,000
C, and the
weight loss of the absorbent (S-1) at that temperature was analyzed. The
analysis results are
shown in FIG. 6. It can be seen from the analysis results in FIG. 6 that the
thermogravimetric loss of the calcium ferrite (CaFe204) absorbent (S-1) can be
reduced to
below 4 wt%, which means that the absorbent (S-1) has excellent thermal
stability.
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[0059] Example 5
[0060] Analysis of thermal stability of the absorbent
[0061] The zinc ferrite (ZnFe204) absorbent (D-1) prepared in Example 2 was
selected
for thermogravimetric analysis to evaluate its thermal stability. With a
thermogravimetric
analyzer (TGA), the test temperature was set to about 1,000 C, and the weight
loss of the
absorbent (D-1) at that temperature was analyzed. The analysis results are
shown in FIG. 7.
It can be seen from the analysis results in FIG. 7 that the thermogravimetric
loss of the zinc
ferrite (ZnFe204) absorbent (D-1) can be reduced to below 4 wt%, which means
that the
absorbent (D-1) has excellent thermal stability.
[0062] Comparative Example 3
[0063] Analysis of thermal stability of the absorbent
[0064] The slag absorbent (S-0) provided in Comparative Example 1 was
selected for
thermogravimetric analysis to evaluate its thermal stability. With a
thermogravimetric
analyzer (TGA), the test temperature was set to around 1,000 C, and the weight
loss of the
absorbent (S-0) at that temperature was analyzed. The analysis results are
shown in FIG. 8.
It can be seen from the analysis results in FIG. 8 that the thermogravimetric
loss of the slag
absorbent (S-0) reaches 16 wt%, which means the thermal stability of the
absorbent (S-0) is
poor.
[0065] Comparative Example 4
[0066] Analysis of thermal stability of the absorbent
[0067] The dust absorbent (D-0) provided in Comparative Example 2 was
selected for
thermogravimetric analysis to evaluate its thermal stability. With a
thermogravimetric
analyzer (TGA), the test temperature was set to around 1,000 C, and the weight
loss of the
absorbent (D-0) at that temperature was analyzed. The analysis results are
shown in FIG. 9.
It can be seen from the analysis results in FIG. 9 that the thermogravimetric
loss of the dust
14
Date Recue/Date Received 2020-09-28
Client's Docket No.: P55080032CA
TT's Docket No.: 9044E-A27040CA/fina11david/Dean
absorbent (D-0) reaches 20wt%, which means the thermal stability of the
absorbent (D-0) is
poor.
[0068] While the disclosure has been described by way of example and in
terms of
embodiments, it should be understood that the disclosure is not limited
thereto. On the
contrary, it is intended to cover various modifications and similar
arrangements (as would
be apparent to those skilled in the art). Therefore, the scope of the appended
claims should
be accorded the broadest interpretation so as to encompass all such
modifications and
similar arrangements.
Date Recue/Date Received 2020-09-28
