JPS60114338A - Carbons and carbon molecular sieves as mercury adsorbent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Mercury vapor has been removed from gas streams by a variety of adsorbents. For example, potassium triiodide (potassi
U.S. Patent No. 3,194,629 describes activated carbon impregnated with sulfuric acid or sulfur; U.S. Patent No. 3,876,393 describes activated carbon impregnated with silver or copper salts No. 3,193,987; and US Pat. No. 4,101,631 which describes zeolites containing elemental sulfur. Generally, these adsorbents are effective only when relatively high concentrations of mercury are present, and each adsorbent has a lower limit below which mercury vapor is either poorly adsorbed or completely unadsorbed. Either.

Sulfur-impregnated nut shell carbons and carbon molecular sieves have been found to be effective against very low concentrations of mercury vapor. It has also been discovered that molecular sieves are less adversely affected by water and temperature than prior art adsorbents.

The present invention uses nut shell carbon impregnated with about 0005 to about 15 weight percent sulfur and 2600 x 104 cr
! /second, with a nitrogen diffusion coefficient of less than about 0.005 to about 15.0%. Preferably, the present invention relates to a carbon molecular sieve impregnated with mercury-reactive material in an amount of 0.001 to 10, and most preferably 3 to 7 percent by weight.

The present invention also provides a process for removing mercury vapor from a gas stream comprising contacting the mercury vapor-containing gas stream with nut shell carbon impregnated with about 0,005 to about 15 weight percent sulfur; flow, 2600
Relating to a process for removing mercury vapor from a gas stream comprising contacting a carbon molecular sieve impregnated with about 0.005 to about 15 weight percent mercury reactant having a nitrogen diffusion coefficient of less than 10-8 crl/sec. It is.

Nut shell carbons impregnated with 0.005 to 15 weight percent, preferably at least 0.01 weight percent, and most preferably at least 3 weight percent sulfur, are capable of absorbing sulfur from the gas stream at low mercury vapor concentrations. These carbons are useful adsorbents for removing mercury vapor.
)XPs, preferably p<(i xlo-')xp s
(where Ps is the saturated vapor pressure of mercury at the specified pressure and temperature) are particularly effective adsorbents in the range of mercury vapor concentrations. Similarly 0.005 to 15
Carbon molecular sieves impregnated with a mercury-reactive substance, preferably 0.01 to 10 weight percent, and most preferably 3 to 7 weight percent, remove mercury vapor from a gas stream at low mercury vapor concentrations. These carbons are useful for removing P ((4X 1
．． 0' ) X P s, preferably P((I
O''' ) XP s, where Ps is the saturated vapor pressure of mercury at the given pressure and temperature.

Carbon molecular sieves have open-network structures with controlled molecular dimensions.
ure ), which can be used to separate mixtures of small molecules from larger molecules based on differences in molecular size or differences in diffusion rates. U.S. Pat. No. 3,884,830 describes the production of activated carbon molecular sieves.

Carbon molecular sieves are manufactured from a variety of substrates by a variety of processes. Examples include anthracite (U.S. Pat. No. 3,222,412); coke or coco shell, high temperature and pore blockage due to carbon precipitation (U.S. Pat. No. 3,801,513); chloride
Nylidene copolymers (U.S. Pat. No. 4.046.709)
and bituminous coal or coco palm shell, high temperature and an inert atmosphere (U.S. Pat. No. 2,556,859). Preferred substrates are coal and nut shells. In addition, in the present invention, the carbon molecular sieve is heated to 2600 ml before impregnation.
x 10'''8 d/sec, preferably I x 10
-7/sec to 2600 x 10-8 d/sec, more preferably 10 x 10 Ad/sec to 2600 x 1 O-8 d/sec
seconds, and most preferably 10×1O-8CI7L
It has a nitrogen diffusion coefficient of 300×10 −8 crl/sec to 300×10 −8 crl/sec.

Removal of mercury vapor from the gas stream by impregnated nutshell carbons or by impregnated carbon molecular sieves can be accomplished by any method available to the skilled person.

Generally, this gas stream is contacted with nutshell carbons impregnated with a high amount of sulfur or carbon molecular sieves impregnated with a mercury-reactive material. This can be accomplished by one or more beds of adsorbent, through which the mercury vapor carrier gas is passed.
Mercury adsorbents such as the carbons described in No. 629 may also be used. These adsorbents are manufactured by Union Carbide.
Corporation) and Calgon Carbon Corporation.
) can be obtained commercially.

In a preferred embodiment of the invention, the mercury vapor-enriched gas stream is made of activated coal-based carbon impregnated with a mercury-reactive material.
carbon) or a zeolite molecular sieve, and the mercury stream is then passed through a nutshell carbon or carbon molecular sieve impregnated with a mercury-reactive material. Examples of mercury-reactive materials that can be used include oxidizing agents and amalgamating metals. Examples of oxidizing agents include S; Feα3:CuS,
Sulfides such as A g S; KI,; KIO3;
NaOα; MnO2 and PbCl2; examples of metals include gold, silver, tin and copper.

Gas streams contemplated within the scope of this invention include natural gas streams, hydrogen gas from chlor-alkali plants, mercury-contaminated industrial gases such as furnace stack gases, and storm battery incinerator gases. etc.; Hydrogen purification gas, etc.; Air, hydrocarbon gases, carbon dioxide, etc.
- Carbon oxides, oxygen, nitrogen, etc.

Any nut shell char can be used, but preferred is coco coconut shell char or babassu coconut shell char. This char may or may not be activated. An example of a commercially available activated coco char char is GRC-II, and an example of a non-activated coco char (carbon molecular sieve) is CMX-1, both manufactured by Carbon Carbon. be. Any nut shell char can be used in the present invention. This nut shell char is produced simply by heating the nut shells to a temperature sufficient to carbonize them. Low oxygen conditions are required to prevent complete combustion. This carbonized shell is generally crushed and sieved to the required mesh size.

The size of the mesh is not an important factor. 3×6 to 50
A US sieve of X100 can be used. The char is optionally activated in the presence of water vapor, carbon dioxide or oxidizing agents. Carbonization and activation are described in US Pat. No. 3,884,830.

Any carbon molecular sieve can be used. For example, CMX-1 manufactured by Carbon Carbon Co., Ltd.
, GRC-II and MSC-V. CMX-1
is a non-activated carbon molecular sieve, GRC
-II and MSC-V are slightly activated carbon molecular sieves.

The carbons or molecular sieves can be impregnated with sulfur by any method. For example, elemental sulfur and particulate carbon may be mixed and heated to about 150°C.

Additional heating to about 150° C. or higher for 10 to 90 minutes will accomplish complete impregnation of the sulfur into the pores of the sieve (molecular sieve). Alternatively, the sulfur may be dissolved in a solvent such as carbon disulfide and this solution contacted with the carbon. Typical methods include spraying, dipping,
and so on. Excess solution is removed by decantation or sieve and the sieve is dried. Drying can be accomplished at room temperature or at elevated temperatures. Direct air may be used to aid in solvent removal.

Table 1 shows the carbons used in Examples 1 to 11.

Table 1 Hg vapor removal limit (μ, 9/rn') 20-25°C Carbon Atmospheric pressure B P L ” 0.071 CMX” 0.0016 GRC-I Ia O, 0018 Babasu coconut shell 0.0040 ” Comparison Approximately 13.6 # (30 pounds) of coco palm charcoal manufactured by Lugon Carbon Co., Ltd.
s) in an enclosed moving belt furnace (enclosed drive)
e-belt furnace).

The furnace temperature was 982°C (1800'F) and the furnace residence time was 30 minutes. A constant nitrogen purge countercurrent to the feed flow at approximately 0.71 standard cubic meters/min (25S
CFM).

(13) 20 The atmosphere was maintained such that oxygen was less than 500 ppm.

To calculate diffusion coefficient values for test gases (e.g. oxygen, nitrogen, etc.), the dead volume of a sample cell containing approximately 10 grams of carbon sieve was
ume ) was measured by helium expansion. Test gas was expanded from the 1 liter control cell into the sample cell, which was again emptied. Since the dead volume was known, any adsorption (loading) of the test gas was monitored by pressure changes in the system. Combining these values with the equilibrium load value calculated for the sieve sample after 1 hour at standard temperature and pressure (STP) yields the specific load value (L,/Le). L, is the test gas loading value of the sieve sample at equilibrium. The gas diffusion coefficient value (D) of the sieve sample was calculated for the test gas by solving the simplified equation for diffusion into the sphere (14).

where D - gas diffusion coefficient t = time expressed in seconds Ro - = average particle size of carbon sieve (0,05125c
m) Reference: Ra L. Dedriek and R.I.B. Beckmann, “Adsorption Mechanism by Activated Carbon from Dilute Aqueous Solutions (K
inetics of advertising by
Activated Carbon from Dilu
te Aqueous 5 solution)”.

LIINllCanjar
) and J-Ae Kosteckii (J-Ae Ko
Stecki), Volume 63, American Institute of Chemical Engineers (Amer.
ican In5titude of Chemica
Engineers), New York (New V
orK ) (1967); Walker, Jr.
, ).

L.G. Austin (L Fist G * Auatin)
) and s-p Nandi
), “Activated Diffusion of Gas in Molecular Sieve Materials”
a5es in Molecular 5ieve M
aterialg)”, written by Ocher, G.R.
Volume 2, Marcel Dekk
er Inc.), New York (1966) and J. Crank, “The Mathematics of Diffusion.”
9, 2nd edition, Clarendon Press, Oxford (1975).

Once the oxygen and nitrogen diffusion coefficient values are obtained, the oxygen/nitrogen selectivity ratio (oxygen/nitrogenselec
tivity ratio): S = D02 /
DN2 can be calculated.

A carbon sieve with the following physical properties was manufactured.

fA) Oxygen diffusion coefficient X 1O-8crl/5ec69
3 (B) Oxygen/nitrogen selectivity ratio 7.19 (C) Oxygen equilibrium volume STP gas gas/g carbon 6.7 (D) Oxygen equilibrium volume STP gas gas c/cc carbon bed volume 4.3
(E) Apparent density 0.64 Example 2 5% (weight/weight) of the carbon of Example 1 ((
The mixture was mixed at 150°C with sufficient sublimated elemental sulfur to give a sulfur loading of W/W)) until the mixture was homogeneous.

This mixture was then heated at 150°C for 90 minutes.

A stream of dry air with an inlet mercury concentration of 17,900 μg/rr1' was passed through the column containing the sulfur-impregnated CMX-1 at a linear velocity of about 23 ft/m4n. The column and inlet air flow were maintained at a temperature of 42° C. and atmospheric pressure.

A contact time of 8 seconds reduces this mercury vapor concentration to 0.005μ,
This was sufficient to reduce the ratio to 9/[11'. The results are shown in Figure 1.

Example 3 The carbon of Example 1 was mixed with sublimated elemental sulfur in an amount sufficient to provide a 5 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was then heated at 150°C for 45 minutes and at 170°C for an additional 4 minutes.
Heated for 5 minutes.

A stream of dry air with an inlet mercury concentration of 30.800 μg/rn' was passed through the column containing the sulfur-impregnated CMX-1 described above at a linear velocity of about 23 ft/min. The column and inlet air flow were maintained at a temperature of 46° C. and atmospheric pressure. A contact time of 8 seconds was sufficient to reduce the mercury vapor concentration to 0.012 μg/rn'. The results are shown in Figure 1.

Example 4 The carbon of Example 1 was mixed with sublimated elemental sulfur in an amount sufficient to provide a 10 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was then heated at 150°C for 90 minutes.

A stream of dry air with an inlet mercury concentration of 22.700 μEl/rn' was passed through the column containing the sulfur-impregnated CMX-1 described above at a linear velocity of 23 ft/min. The column and inlet air flow were maintained at a temperature of 44° C. and atmospheric pressure. A contact time of 8 seconds was sufficient to reduce the mercury vapor concentration to 0.014 μg/rn+. The results are shown in Figure 1.

Example 5 The carbon of Example 1 was mixed with sublimated elemental sulfur in an amount sufficient to provide a 10 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was heated at 150°C for 45 minutes and at 165°C.
Heated for an additional 45 minutes at <0>C.

21. A stream of dry air with an inlet mercury concentration of 200μ, 9/m' was passed through a column containing sulfur-impregnated coco palm char at a linear velocity of 23 ft/min. The column and inlet air flow were maintained at a temperature of 44° C. and atmospheric pressure. A contact time of 8 seconds was sufficient to reduce the mercury vapor concentration to 0.008 μg/m'. The results are shown in Figure 1.

Example 6 Dry air with high mercury vapor concentration was impregnated with sulfur (1
Atmospheric pressure and 2
Passage was carried out at temperatures of 0°C and 42°C. A sample was taken from a port along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of air is approximately 7.0 m/min (23 ft/min).
min).

The sulfur-impregnated carbon of Example 1 was replaced with Union Carbide 1.
The above method was repeated at 18° C. and 42° C. with /16 molar sieves (sulfur-impregnated zeolite mercury adsorbent).

The results obtained at 42°C (Fig. 2) show that the mercury vapor removal limit (o, oos μg/m') of the sulfur-impregnated zeolite is lower than that of the sulfur-impregnated carbon of Example 1 (0,003 μg/m').
/m). It should also be noted that the removal limit of carbon molecular sieves does not appear to be strongly dependent on the partial pressure of mercury.

The results obtained at low temperatures (18 and 20°C) (Figure 3) indicate that the union carbide mole sieve is ineffective due to its very low mercury vapor removal mechanism (at 18°C). There is. Sulfur-impregnated coco palm char has O,OO2tt9/rr? at almost the same temperature (20℃). with lower mercury vapor removal limits.

Example 7 Dry air with high mercury vapor concentration was impregnated with sulfur (15
A 7.0 ml min.
) at a linear velocity of The pressure and temperature were atmospheric and room temperature. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent.

The method was repeated replacing the dry air with H20 saturated air. The analysis was carried out after continuing the passage of this H20 saturated air through the column for 16 hours.

The above sulfur-impregnated coco palm ÷ 4 sulfur-impregnated GRC-II [
containing 15% (W/W) sulfur impregnated at 1150°C and subsequently heated at 150°C for 90 minutes]
The above method was repeated with both.

GRC-II I is an activated coco coconut shell based carbon. As expected, the mercury vapor removal limit is the same for both types of dry adsorbent beds (Figure 4).

As can be seen from Figure 4, the mercury vapor removal limit of sulfur-impregnated GRC■ is affected by the absorbed H2O, while that of sulfur-impregnated coco palm char
It is not affected strongly because it is contracted to suppress easy adsorption.

Example 8 The carbon of Example 1 was sprayed with an aqueous solution of ferric chloride.

(]4g Feα3・6H20, 100ml H2O,
700g of CMX-1). The resulting wet carbon was air dried for several days. The impregnated carbon was placed in a column through which mercury-saturated air was passed at 20°C. A sample was taken from a port along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent.

The linear velocity of air is 7.0 m/min (23 ft/min)
Met. The results are shown in Figure 5.

Example 9 Example 10 A carphone was sprayed with an aqueous solution of potassium triiodide. (19,0g of KI, 85g of 12.300c
c of water, 700 g of CMX-1). The resulting wet carbon was air dried for several days. This impregnated carbon was placed in a column and mercury vapor saturated air was passed through the column at 20°C. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air was about 7.0 m/min (23 ft/min). The results are shown in Figure 6.

Calcined babassu palm char (10x30 mesh, 950℃
(calcined at ) was mixed with enough sublimed elemental sulfur to give a sulfur loading of 5 percent (W/W) until the mixture was homogeneous. This mixture was then heated at 150°C for 90 minutes.

Dry air with a high mercury vapor concentration was passed through this sulfur-impregnated calcined babassu palm char at 20° C. and atmospheric pressure. Samples were taken from ports along the length of the column and the concentration of mercury vapor in the air was measured after a known contact time with the adsorbent. The linear velocity of this air was 7.0 ml/min (23 ft/min). The mercury vapor removal limit of this sulfur-impregnated MSC-V is 0.004μ
, 9/rn'' (Fig. 7).

Dry air with high mercury vapor concentration is
BPL (15% (W) based) activated carbon
/W) sulfur-impregnated and manufactured by Carbon Carbon Co., Pittsburgh, Pennsylvania.
5ylvania) at 24° C. and atmospheric pressure. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air was 7.0 m1 min (23 ft/m1 n).

The mercury vapor removal limit of this BPL is 0 under these conditions.
．． The result (FIG. 8) was 0.071 μg/In'.

Carbons used in Examples 12 to 24 are shown in Table 2.

Table 2 Hg vapor removal limit (μg/mash) 20-25℃ Nitrogen diffusion coefficient Carbon Atmospheric pressure (×1 second) B P L
” 0.071 2786 Belbubara 0.025 2
．． 14 (Bergbau) CM -1aO, 001659,:3 M5C-VaO, 0042527 GRC-I I aO, 00182200 Babassu coconut shell 0.0040 170 7 For comparison (not molecular sieve) 8 Power b Bell Keba manufactured by Rugon Carbon Co. 9 Bergbau Forshung
) Preparation Example 12 Production of CMX-1 Coco palm char was made at a rate of about 13.6 # (30 pou) per hour.
nds) in a closed moving belt furnace [belt width is 0.55
m (221nch)] Hefeeded. The furnace temperature was 982°C (1800°F) and the furnace residence time was 30 minutes. A constant nitrogen purge was maintained at about 0.71 standard cubic meters per minute (25 SCFM) in a countercurrent direction to the feed flow. The atmosphere was maintained at less than 500 ppm oxygen.

To calculate diffusion coefficient values for test gases (e.g. oxygen, nitrogen, etc.), the dead volume of a sample cell containing approximately 10 grams of carbon sieve was
ume ) was measured by helium expansion. Test gas was expanded from a 1 liter control cell to a per-nitrided sample cell. Since the dead volume was known, any test gas adsorption (loading) was monitored by pressure changes in the system.

These values are combined with the equilibrium load value calculated for the sieve sample after 1 hour at standard temperature and pressure (STP) to obtain the specific load value (Lt/L, ). L
t is the test gas loading value of the sieve sample at a predetermined time, for example 30 seconds, and L is the test gas loading value of the sieve sample at equilibrium. Gas diffusion coefficient values (D) for the sieve samples were calculated for the test gas by solving a simplified equation for diffusion into the sphere.

In the formula, D = time in which the gas dispersion coefficient value is expressed in - seconds Ro - average particle size of the carbon sieve (0,05125 = m
)Reference: R-L-Dedr
ick) and R.P. Beckman (RaB
Kinetics of Adsorption by Activated Carbon from 6 Dilute Aqueous Solutions of M Beckmann)
sorption by Activated Car
bon from Dilute Aqueous 5o
lution )”, Physical adsorption campaigner (L-N
@Canjar and J.A. Kostecki, Volume 63, American Institute of Chemical Engineers.
chemical Engineers), New York (
New York ) (1967); P#L-WalkerS Jr.
), L*G-Aust
in) and Nis P. Chindi (S-P@Nand
1) Activated Diffusion of Gas in Molecular Sieve Material
Ga5esin Mo1ecular 5ieve
Materials)”, Carbocar, GRA,
Author, Volume 2, Marcel De
Kker Inc. ), New York (1966)
and J Crank,
”The Mathematics of Diffusion
Diffusion”, 2nd edition, Clarendon Press, Oxford (1975).

Once the oxygen and nitrogen diffusion coefficient values are obtained, the oxygen/nitrogen selectivity ratio (Oxygen/nitrogenselec
tivity ratio): S = DO2/
DN2 can be calculated.

A carbon sieve with the following physical properties was manufactured.

(A) Oxygen diffusion coefficient X 10-ffl/sec 6
93 (B) Oxygen/nitrogen selectivity ratio 7.19 (C) Oxygen equilibrium volume STP gas gas/g carbon 67 (D) Oxygen equilibrium volume STP gas gas/cc carbon bed volume 43 (E) Apparent density 0.64 Example 13 The carbon molecular sieve of Example 1 was mixed with sufficient sublimated elemental sulfur to give a 5 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was then heated at 150°C for 90 minutes.

A stream of dry air with an inlet mercury concentration of 17.900 μ97 m′ was passed through the column containing the sulfur-impregnated CMX-1 at a linear velocity of about 70 m/min (23 f t/m 1 n). The column and inlet air flow were maintained at a temperature of 42° C. and atmospheric pressure.

A contact time of 8 seconds reduces this mercury vapor concentration to 0.005μ,
This was sufficient to reduce the amount to 9/rn'. The results are shown in Figure 9.

The carbon molecular sieve of Example 1 was mixed with sufficient sublimated elemental sulfur to provide a 5 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was then heated at 150°C for 45 minutes and 1
Heated at 70°C for an additional 45 minutes.

A stream of dry air with an inlet mercury concentration of 30,800 ttji/m' was passed through the column containing the sulfur-impregnated CMX-1 described above at a linear velocity of about 7.0 ml min (23 ft/min). Column and inlet air flow at 46°C
temperature and atmospheric pressure. A contact time of 8 seconds was sufficient to reduce the mercury vapor concentration to 0.012 μg/m'. The results are shown in Figure 9.

The carbon molecular sieve of Example 1 was mixed at 150°C with sufficient sublimated elemental sulfur to provide a 10 percent (W/W) sulfur loading until the mixture was homogeneous.

This mixture was then heated at 150°C for 90 minutes.

A stream of dry air with an inlet mercury concentration of 22.700 μg/m was passed through the column containing the sulfur-impregnated CMX-1 described above at a linear velocity of about 23 ft/min. The column and inlet air flow were maintained at a temperature of 44° C. and atmospheric pressure. A contact time of 8 seconds was sufficient to reduce the mercury vapor concentration to 0.014 μg/m'. The results are shown in Figure 9.

The carbon molecular sieve of Example 1 was mixed with sufficient sublimated elemental sulfur to provide a 10 percent (W/W) sulfur loading at 150° C. until the mixture was homogeneous. This mixture was heated at 150°C for 45 minutes and at 165°C.
Heated for an additional 45 minutes at <0>C.

21. A stream of dry air with an inlet mercury concentration of 200 μg/rr1' was passed through a column containing sulfur-impregnated coco palm char at a linear velocity of 7.0 m/min (23 ft/min). The column and inlet air flow were maintained at a temperature of 44° C. and atmospheric pressure.

A contact time of 8 seconds reduces this mercury vapor concentration to 0008μ9/
This was sufficient to reduce the temperature to m'. The results are shown in Figure 9.

Example 17 Dry air with a mercury vapor concentration was impregnated with sulfur (15
It was passed through the carbon molecular sieve of Example 1 (with 5% sulfur loading) impregnated with a heating time of 90 minutes at 0°C at atmospheric pressure and temperatures of 20°C and 42°C.

Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of air is approximately 70 m/
minute (23ft/min).

The sulfur-impregnated carbon of Example 1 was replaced with Union Carbide 1.
The above method was repeated at 18° C. and 42° C. with /16 molar sieves (sulfur-impregnated zeolite mercury adsorbent).

The results obtained at 42°C (Figure 10) show that the mercury vapor removal limit (o, oosμ, !9/m) of sulfur-impregnated zeolite
' is that of the carbon of Example 1 impregnated with sulfur (0,0
03ttg/rm). The removal limit of carbon molecular sieves is larger than the partial pressure of mercury (
It should also be noted that it does not appear to be dependent.

Results obtained at low temperatures (18 and 20 °C) (11th
Figure) shows that union carbide mole sieves are ineffective due to very low mercury vapor removal mechanisms (at 18°C). Sulfur-impregnated coco palm char has a mercury vapor removal limit lower than O,OO2μji/m' at approximately the same temperature (20°C).

Dry air with high mercury vapor concentration was impregnated with sulfur (15
at a linear velocity of 23 f t/min through a column containing the carbon molecular sieve of Example 1 (with a 5 percent sulfur loading) impregnated at 0° C. and heated for 90 minutes at 150° C. I let it pass.

Pressure and temperature were atmospheric pressure and room temperature.

A sample was taken from a port along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent.

The method was repeated replacing the dry air with H20 saturated air. The analysis was carried out after 16 hours of continuous passage of this H2O-saturated air through the column.

The above method was used instead of the sulfur-impregnated coco palm char with the sulfur-impregnated GRC-■ process [15% (W/W) sulfur-containing product impregnated at 150°C and then heated at 150°C for 90 minutes]. Both were repeated.

cRc-II I is carbon based on coco coconut shell and is activated carbon. As expected, the mercury vapor removal limits were the same for both types of dry adsorbent beds (Figure 12).

As can be seen from Figure 12, the mercury vapor removal limit of the sulfur-impregnated GRC■ is affected by the absorbed H2O;
That of sulfur-impregnated coco palm char has a pore size of H2
It is strongly contracted to suppress the easy adsorption of O (it is not affected by this).

A water bath solution of ferric chloride was sprayed onto the carbon molecular sieve of Example 1. (14I FeCk” 6H20,
100 ml H2O, 700,9 CMX-1). The resulting wet carbon was air dried for several days. This impregnated carbon is put into a column, and mercury-saturated air is passed through it for 20 minutes.
Passed at ℃. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of the air was 7.0 m/min (23 ft/min). The results are shown in FIG.

The carbon molecular sieve of Example 1 was sprayed with an aqueous solution of potassium triiodide.

(19.0.9 KL, 8.59 I2, 300cc water, 700g CMX-1). The resulting wet carbon was air dried for several days. This impregnated carbon was placed in a column, through which mercury vapor saturated air was passed at 20°C.

Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air is approximately 7
．． The speed was 0 m 1 minute (23 ft/min). The results are shown in FIG.

Dry air with high mercury vapor concentration is passed through a coal-based activated carbon, BPL (impregnated with 15 percent (W/W) sulfur, manufactured by Carbon Carbon Co., Pittsburgh, Pennsylvania) at 24°C and atmospheric pressure. I let it happen.

Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air was approximately 7.0 ml/min (23 ft/min). The mercury vapor removal limit of this BPL is 007 under these conditions.
The result (FIG. 15) was 1 μj; l/rn'.

MSC-V (calcium carbon dioxide, Pittsburgh)
A slightly activated coal-based molecular sieve (commercially available from Pennsylvania) was heated at 150°C with sufficient sublimated elemental sulfur to give a 5 percent (W/W) sulfur loading.
The mixture was mixed until the mixture was homogeneous. This mixture was then heated at 150°C for 90 minutes.

This sulfur-impregnated MSC-
Passed through V at 20° C. and atmospheric pressure. The air concentration was measured along the length of the column. The linear velocity of this air was 7.0 m7 minutes (23 ft/min).

The mercury vapor removal limit of this sulfur-impregnated MSC-V is 0.00
The result (Figure 16) was 4 μg/m'.

Calcined babassu palm char (10x30 mesh, 950℃
(calcined at ) was mixed with enough sublimed elemental sulfur to give a sulfur loading of 5 percent (W/W) until the mixture was homogeneous. This mixture was then heated at 150°C for 90 minutes.

Dry air with a high mercury vapor concentration was passed through this sulfur-impregnated calcined babassu palm char at 20° C. and atmospheric pressure. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air was approximately 7.0 ml/min (23 ft/min). The mercury vapor removal limit of this sulfur-impregnated babassu palm char is 0.
004μ, 9/rn' (Fig. 17).

Berubara Molecular Sieve, a coal-based carbon molecular sieve (manufactured by Berubara), was mixed at 150° C. with sufficient sublimated elemental sulfur to give a 5 percent (W/W) sulfur loading. Add this mixture to 1
Heated at 50°C for 90 minutes.

Dry air with a high mercury vapor concentration was passed through a sulfur-impregnated Berubara molecular sieve at 20° C. and atmospheric pressure. Samples were taken from ports along the length of the column to measure the concentration of mercury vapor in the air after a known contact time with the adsorbent. The linear velocity of this air is 7.
0 m 1 minute (23 ft/min).

The results showed that the mercury vapor removal function of this sulfur-impregnated carbon was extremely low (Figure 18). Mercury vapor removal limits were not reached within this column length. When the inlet mercury vapor concentration decreases (lower line in Figure 18),
This mercury vapor removal function became even more sluggish.

The mercury vapor removal limit is 0.025μ for practical contact times.
It is expected that it will arrive at a value slightly lower than g/rn'.

[Brief explanation of the drawing]

1 to 18 show the relationship between the contact time with the adsorbent and the mercury concentration in the gas in Examples 2 to 11 and Examples 13 to 24, respectively. (43) Continuation of page 1 Priority claim November 3, 2019 [phase] United States (U.S.
)0 Inventor Michael Greenba Amenda -
954B472 United States of America, 15061 Pennsylvania, Monaca, Palain 5010

Claims (1)

Claims: ■ Nut shell carbon impregnated with about 0.005 to about 15 weight percent sulfur. 2. A process for removing mercury vapor from a gas stream comprising passing the mercury vapor-containing gas stream in contact with nut shell carbon impregnated with about 0.005 to about 15 weight percent sulfur. 3. Initial mercury vapor level at a given pressure and temperature, P is P((5,5X10')XPs, where Ps is the saturated vapor pressure of mercury at the given pressure and temperature)
Process according to claim 2, characterized in that the concentration is in the range represented by: 4. comprising sequentially contacting the gas stream with (a) coal-based activated carbon impregnated with a mercury-reactive substance and (b) nut shell carbon impregnated with 0.005 to about 15 weight percent of a mercury-reactive substance; A process that removes mercury vapor from a characterized gas stream. 5. comprising sequentially contacting the gas stream with (a) a zeolite molecular sieve impregnated with a mercury-reactive material and (b) a nut shell carbon impregnated with 0.005 to about 15 weight percent of a mercury-reactive material. A process that removes mercury vapor from a characterized gas stream. 6. A carbon molecular sieve having a nitrogen diffusion coefficient of less than 2600 x 10-crl/sec and impregnated with about 0.005 to about 15 weight percent mercury-reactive material. 7. Gas flow containing mercury vapor is 2600x10=
with a nitrogen diffusion coefficient lower than crl/sec, approximately 0.00
A process for removing mercury vapor from a gas stream comprising passing it in contact with a carbon molecular sieve impregnated with 5 to about 15 weight percent mercury-reactive material. 8. Prior to contacting the gas stream with the carbon molecular sieve impregnated with a mercury-reactive substance, the gas stream is first contacted with carbon impregnated with a mercury-reactive substance. The process described in. 9. Prior to contacting the gas stream with the mercury-reactive impregnated carbon molecular sieve, the gas stream is first contacted with a zeolite molecular sieve impregnated with a mercury-reactive substance. Process described. 10. The initial mercury vapor concentration at a given pressure and temperature, P is in the range P ((5,5XIO') x P s, where Ps is the saturated vapor pressure of mercury at the given pressure and temperature. 8. A process according to claim 7, characterized in that: