JPS5932922A - Adsorbing bed for purifying gas containing sulfur compound - Google Patents

Abstract

PURPOSE:To attain to remove pollution impurities such as a sulfur compound and benzene in high efficiency, by a method wherein a water supply pipe is provided to the almost intermediate part of a tower body filled with activated carbon or coalite as an adsorbent and the lower part thereof is formed into a wet adsorbent layer while the upper part thereof is formed into a dry adsorbent layer. CONSTITUTION:Water is supplied to a tower body 1 from a water supply conduit 3 and, among the adsorbent 2 such as activated carbon or coalite filling the tower body 1, the adsorbent filling the part of said tower body 1 lower than the conduit 3 is used as a wet adsorbent 2a and the adsorbent fillng the upper part as a dry adsorbent 2b. In this case, the moisture content of the wet adsorbent 2a is adjusted to about 20-80wt% on the basis of the wt. of the adsorbent. A compressed gas containing a sulfur compound such as hydrogen sulfide and pollution impurities such as benzene, toluene or tar mist is introduced into the adsorbing bed A through a valve 8. A small amount of H2S and the greater part of pollution impurities are removed by the adsorbent 2b and the greater part of H2S is subsequently removed by the adsorbent 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to gas adsorption purification that effectively removes sulfur compounds from gases containing other impurities in addition to sulfur compounds such as hydrogen sulfide and carbonyl sulfide, and simultaneously removes other impurities. This relates to adsorption beds for use in industrial applications.

For example, coke oven exhaust gas (hereinafter referred to as COG)
Since it contains a large amount (50-60%) of hydrogen, attempts are being made to recover hydrogen from this COG. However, this COG contains contaminants such as sulfur compounds such as hydrogen sulfide, tar-like substances, water, benzene, toluene, and xylene, as well as light hydrocarbons represented by CmHn, carbon monoxide, carbon dioxide gas, nitrogen, and oxygen. include. For this reason, after the above-mentioned contaminating impurities are removed in advance, carbon monoxide, light hydrocarbons, nitrogen, oxygen, etc. are removed by a cryogenic separation method or adsorption separation method, and the target hydrogen is recovered. By the way, the above-mentioned contaminant impurities are generally removed by an absorption method using an alkaline solution or by an adsorption device called a guard bed, which is composed of an adsorption bed filled with an adsorbent such as activated carbon or semi-formed coke. If the above-mentioned contaminant impurities are not completely removed by the absorption liquid or the guard bed suction bed, they will be sent to the next step, the cryogenic separation device or the adsorption separation device, and the device will be clogged with these contaminant impurities or the adsorbent will deteriorate. This is undesirable because it causes problems in operation and also causes contaminant impurities to be mixed into the hydrogen product. Therefore, in order to remove these contaminant impurities more completely with the adsorption bed of the guard bed, multiple adsorption beds each filled with an adsorbent suitable for each contaminant impurity component are provided, and the raw material gas is sequentially passed through these beds to remove the contaminant impurities. The reality is that the . However, in this method, the effect of adsorption and removal of sulfur compounds in particular is poor, and desorption regeneration for reusing the adsorption bed after adsorption is difficult. Inconveniences arise, such as an increase in scale and a complicated operation.

On the other hand, when sulfur compounds such as hydrogen sulfide coexist with water,
It has been well known that the adsorption capacity of adsorbents such as activated carbon and semi-formed coke increases.

The present invention was made in view of the above-mentioned current situation, and its purpose is to remove contaminant impurities of the same type from COG, which contains sulfur compounds such as hydrogen sulfide, and contaminant impurities such as benzene, toluene, xylene, and tar mist. By using an adsorption bed using only activated carbon or semi-formed coke to reduce equipment costs,
This aims to simplify the operation and improve the effectiveness of adsorption and removal of sulfur compounds.The tower is filled with activated carbon or semi-formed coke as an adsorbent, and a water tank is installed in the tower that opens approximately in the middle of the tower. An adsorption bed characterized in that a supply conduit is provided to moisten an adsorbent such as activated carbon or semi-formed coke in the lower part of the tower with water, and gas inlets and outlets are provided at the top or bottom of the tower, respectively. be. Another variation is an adsorption bed located above the water supply conduit, partially filled with a desiccant such as silica gel or alumina gel, and interposed in layers with the activated carbon or semi-coarse layer. The adsorption bed of the present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the adsorption bed A of the first invention, in which 1 is a hollow closed column body, and 2 is an adsorbent such as activated carbon or semi-formed coke filled in the column body 1. . Reference numeral 3 denotes a water supply conduit, the end of which extends into the tower body by passing through the wall of the tower body in an airtight manner, and a plurality of suitable small holes are opened inside the tower body 1.

By supplying water through the pipe 3, among the adsorbents 2 such as activated carbon or semi-formed coke filled in the column body 1, the adsorbents located below the water supply conduit 3 become wet adsorbents 2.
a, and the adsorbent located above is the dry adsorbent 2b.
It is placed as. The moisture content of the wet adsorbent 2a should be 20 to 80% by weight based on the weight of the adsorbent to maintain the adsorption and removal effect of sulfur compounds and the adsorption capacity of the adsorbent 2 for a long period of time. preferable. If the water content is less than 20%, the adsorption capacity is the same as in a dry state, and if it is more than 80%, the adsorption capacity is lowered due to too much water and the desired effect cannot be obtained. 4 and 5 are openings provided at the top and bottom of the tower, respectively.
Pipes 6 and 7 are connected to the opening 5 and the opening 5, respectively. Reference numerals 8 and 9 are valves connected to the pipes 6 and 7, respectively.

Next, the operation of the adsorption bed A was carried out at 200 p.p. of hydrogen sulfide. p
．． m. , oxygen 3,000 ppm, benzene 1000 p.
p. m. , nitrogen gas containing 10Nm/hr. A case will be explained by exemplifying a case where the gas is purified using as a raw material gas.

Type of adsorbent 2 filled in adsorption bed A and ■: activated carbon 400
g.

Amount of activated carbon adsorbent 2a positioned below the water supply conduit 3 and moistened: 350 g; Amount of water supplied to the moistened absorbent 2a: 200 g; Activated carbon adsorbent positioned above the water supply conduit 3 and dried. Amount of 2b: 5
0g, first valve 8 is opened and the above raw material gas is 10Nm/hr. 10
It is compressed to kg/cm2G and introduced into the adsorption bed A from the top of the column through the opening 4 through the pipe 6. While the feed gas introduced into the adsorption bed A passes through the dry activated carbon adsorbent (2b), a smaller amount of hydrogen sulfide is adsorbed, but most of the benzene, which is more easily adsorbed, is adsorbed and removed, leaving the wet activated carbon. Adsorbent (2a)
flow into the layer of

While passing through the moistened activated carbon adsorbent (2a), most of the hydrogen sulfide contained in the raw material gas is removed by the wet activated carbon adsorbent (2a) and passes through the bottom opening 5 to the pipe 7. It is led out from valve 9 as purified gas.

When the purified gas thus obtained was analyzed, impurities such as hydrogen sulfide and benzene contained in the raw material gas were all found to be 1p. p. It was less than m. As a result of continuing this adsorption removal operation for 4 hours, the impurities in the purified gas were reduced to 1p. p. m or less. After that, the adsorption removal operation was stopped, and the inside of the adsorption bed A was returned to normal pressure.
High-purity nitrogen gas is heated to 200°C or higher, passed through the tube 6 into the adsorption bed A, and exhausted through the tube 7 for desorption and regeneration. After the regeneration process of cooling it to room temperature, the adsorption and removal operation is performed again for regeneration. Even after repeating the adsorption removal process 10 times, the above performance was maintained.

For comparison, when all the adsorption beds were filled with dry activated carbon and the same raw material gas was purified under the same conditions, hydrogen sulfide flowed out after 1 hour of adsorption and removal, and sufficient adsorption and removal could not be achieved. Ta.

Figure 2 shows an adsorption bed B of the second invention, which is a modification of the above adsorption bed A.
The same symbols as in FIG. 1 indicate the same configuration, and adsorption bed B is the adsorption bed A shown in FIG. agent layer (2a) and a dry activated carbon adsorbent layer (2b) arranged above.
) is provided with a dry adsorbent layer 10 of silica gel, alumina gel, etc. In this case, the raw material gas is introduced into the adsorption bed B through the bottom opening 5 of the column body 1 from the valve 9 pipe 7,
The water is allowed to flow upward in the column body 1, and most of the sulfur compounds such as hydrogen sulfide are first adsorbed and removed by the wet activated carbon adsorbent layer 2a, and then passed through the wet activated carbon adsorbent layer 2a at the desiccant adsorption layer 10. After adsorbing and removing the moisture entrained by the drying, the activated carbon adsorbent layer (2b) flows into the dry activated carbon adsorbent layer (2b). Therefore, the raw material gas flowing into the dry activated carbon adsorbent layer 2b is in a dry state and does not moisten the dry activated carbon adsorbent layer 2a. Therefore, impurities other than sulfur compounds such as hydrogen sulfide, such as benzene, toluene, xylene, ammonia, etc., are efficiently removed by the dry activated carbon adsorbent layer 2b, and then removed from the pipe 6 and valve 8 through the column top opening 4. It is extracted as refined gas.

In this way, when adsorption bed B is used to remove contaminant impurities from COG gas, not only can the same removal effect as adsorption bed A explained in Figure 1 be obtained, but also no moisture is entrained. Dry purified gas is obtained. Note that regeneration of adsorption bed B is performed by heating (200°C
Nitrogen gas, etc. obtained above) flows into the adsorption bed B and
After heating and desorption by discharging from the column, nitrogen gas at room temperature is then passed from the top opening 4 to the bottom opening 5 to cool the adsorption bed B, and thereafter the vapor adsorption purification-desorption regeneration operation is carried out. It can be used continuously by repeating the steps.

In the above embodiments, activated carbon was used as an example of the single adsorbent used, but the present invention is not limited to activated carbon, and semi-formed coke can also be used with the same effect as activated carbon.

As described above, in the present invention, either one of the adsorbents such as activated carbon or semi-formed coke is filled into a column body having openings connected to the tubes at the top and bottom, and approximately at the middle of the column. A water supply conduit was installed at the bottom of the adsorbent column to form a wet adsorbent layer in the lower part of the adsorbent column and a dry adsorbent layer in the upper part, so that sulfur compounds and other contaminant impurities such as benzene, toluene, xylene, ammonia, etc. Not only can sulfur compounds be effectively removed in the same adsorption tower, but also sulfur compounds that could not be desorbed satisfactorily in the past can be desorbed and regenerated, making it possible to use them repeatedly over a long period of time. . In addition, since many contaminants can be removed by using a single adsorbent, there is no need to prepare many adsorbents for each component, making it economical and simplifying equipment specifications. Equipment costs can be reduced and device operation can be simplified. Furthermore, the structure in which a desiccant layer is provided between the dry adsorbent layer and the wet adsorbent layer has many advantages, such as the fact that the gas after adsorption and purification can be obtained in a dry state.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view illustrating an embodiment of the adsorption bed of the first invention, and FIG. 2 is a schematic sectional view illustrating an embodiment of the adsorption bed of the second invention. 1... Tower body, 2... Adsorbent, 3...
... Water supply conduit, 10 ... Desiccant layer. Out [1 @ Nippon Sanso Co., Ltd.

Claims (4)

[Claims] (1) A column body with pipes connected to the top and bottom openings is filled with either activated carbon or semi-formed coke as an adsorbent, and a water supply conduit opens into the column approximately in the middle of the column body. The adsorbent below the position of the water supply conduit is moistened with water to form a wet absorbent layer, while the part above the water supply conduit is formed as a dry adsorbent layer. Adsorption bed for purifying gas containing sulfur compounds. (2) The moisture content of the wet adsorbent layer is 20 to 80% of that of the adsorbent.
The adsorption bed for purifying a gas containing sulfur compounds according to claim 1, characterized in that the sulfur compound is % by weight. (3) A column body with five pipes connected to each of the top and bottom openings is filled with either activated carbon or semi-formed coke as an adsorbent, and an opening is opened into the column approximately in the middle of the column body. A water supply conduit is provided, and a portion of the adsorbent below the location of the water supply conduit is moistened with water to form a wet absorbent layer, while a portion above the water supply conduit is provided with a dry adsorbent layer. An adsorption bed for purifying gas containing sulfur compounds, further comprising a desiccant layer such as silica gel or alumina gel between the wet adsorbent layer and the dry adsorbent layer. (4) The moisture content of the wet adsorbent layer is 20 to 80% of that of the adsorbent.
The adsorption bed for purifying a gas containing sulfur compounds according to claim 3, characterized in that the sulfur compound is % by weight.