JPS59232174A - Method for purifying coke oven gas - Google Patents

Abstract

PURPOSE:To purify coke oven gas efficiently, by bringing coke oven gas contg. a tar oil component and gum as impurities into contact with a porous material to adsorb and remove the impurities. CONSTITUTION:Coke oven gas contg. a tar oil component and gum as impurities at a space velocity of 100-10,000h<-1> is introduced into an adsorption tower 2, where the gas is brought into contact with a porous material (e.g. alumina) having a BET suface area of 10m<2>/g or above and a pore volume of 0.1ml/g or above to adsorb and remove the impurities. The coke oven gas 1 is then introduced into a hydrogenation tower 3 and is directly hydrogenated in the presence of 1-25wt% Ni and/or Co-supported or 2-15wt% Ni and/or Co and 3-40wt% Mo-supported catalyst at 50-450 deg.C and a space velocity of 500- 50,000h<-1> under a pressure of 2-100atm to hydrogenate the impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for purifying coke oven gas containing at least tar oil and gum substances as impurities.
In particular, the present invention relates to a method for purifying coke oven gas that includes an adsorption step for adsorbing and removing the tar oil and gum substances.

[Background of the invention]

Conventional coke oven gas purification methods include, for example, hydrogenation of dienes, oxygen, olefins, and sulfur compounds through a hydrodesulfurization process using a catalyst system containing nickel and/or cobalt and molybdenum. It has been known. However, these conventional methods have a problem in that tar oil and gum substances contained in the coke oven gas cover the active sites of the catalyst, significantly reducing the catalyst activity.

Furthermore, the dienes in the coke oven gas polymerize and the gas
This method has the drawback of producing a mucus-like substance, resulting in a decrease in catalyst activity and clogging of the catalyst layer.

[Purpose of the invention]

An object of the present invention is to provide a method for efficiently purifying coke oven gas without the above-mentioned drawbacks of the prior art.

[Summary of the invention]

To summarize the invention, the present invention provides a method for purifying coke oven gas containing at least impurities tar oil and gum material by contacting the coke oven gas with a porous material to produce the tar oil and gum material. The present invention relates to a coke oven gas purification method characterized by including an adsorption step for adsorbing and removing substances.

The coke oven gas from which tar oil and gum substances have been removed can be used as various raw material gases, etc., but the coke oven gas obtained from the adsorption process as described above is further catalytically hydrogenated to remove impurities with hydrogen. It is also useful to further purify the coke oven gas by treating it with a hydrogenation step.

The invention therefore relates to a method for purifying coke oven gas by combining said adsorption step and a hydrogenation step.

Therefore, one embodiment of the present invention is a coke oven gas purification method using a combination of the above steps, in which a part of the purified gas is recycled before or after the adsorption step, and a part of the purified gas is recycled before or after the hydrogenation step. It is characterized by adjusting the temperature so that it does not exceed 450C. This method is useful for maintaining the activity of the hydrogenation catalyst.

Examples of porous materials (hereinafter abbreviated as adsorbents) used in the adsorption process of the present invention include alumina, silica, zeolite, iron oxide (Fe203), titania, magnesia, diatomaceous earth, calcium oxide, selected from the group consisting of carbonia, activated carbon and mixtures thereof. Particularly preferred are alumina, silica, and activated carbon.

The adsorbent has a BET surface area of iom'/g or more, preferably in the range of 20 m' to 1000 m'/g.

The pore volume has a pore volume of 0.10 mt/g or more, preferably 0.
．． It is in the range of 15 to 0.60 mt/g. The adsorbent has high hygroscopicity and adsorbs moisture in the air, reducing its adsorption performance. Therefore, the adsorbent should be kept at an appropriate temperature, preferably 300 to 400C, before use.
It is preferable to dry at a temperature of . The temperature of adsorption performed using an adsorbent is in the range of room temperature to 300C, preferably in the range of room temperature to 200C. When the temperature exceeds 300C, the adsorption performance decreases. The feed rate of coke oven gas to this adsorbent is preferably 100 to 10,000 h"' in terms of space velocity. If the space velocity is less than 100 h-1, the amount of adsorption used becomes large, which is uneconomical;
If it exceeds this, the adsorption capacity will decrease. The pressure for adsorption is 2~
The pressure may be 100 atm, but is not particularly limited.

The conditions of the hydrogenation step vary depending on the catalyst used. Examples of catalysts used include catalysts supported on nickel and/or cobalt, catalysts supported on nickel and/or cobalt and molybdenum, or catalysts supported on platinum group metals. Examples of these supports are alumina, titania or magnesia.

The composition of the catalyst supporting nickel and/or cobalt is:
It is preferable to contain nickel and/or cobalt in a proportion of 1 to 25% by weight and the carrier in a proportion of 99 to 75% by weight. Almost completely hydrogenated.

The composition of the catalyst supporting nickel and/or cobalt and molybdenum is 2 to 15% of nickel and/or cobalt.
It is preferable to contain molybdenum in a proportion of 3 to 40% by weight and the balance as a carrier, and these catalysts efficiently hydrogenate olefins and sulfur compounds, which are impurities in coke oven gas.

Further, the composition of the catalyst supporting the platinum group metal is preferably such that the platinum group metal is contained in a proportion of 0.01 to 5% by weight and the carrier is contained in a proportion of 99.99 to 95°O by weight. Impurities in the furnace gas, such as dienes, oxygen, olefins, and sulfur compounds, are completely hydrogenated.

Each of the above catalysts except platinum group metal catalysts should be
Since the metal catalyst component is in the form of an oxide, it is usually reduced before use. The reduction temperature is usually 250 to 500
It is C. After this reduction, the metal catalyst component is sulfurized before use, which is suitable for suppressing methanation reaction and improving hydrogenation activity.

The reaction temperature in the above hydrogenation step varies slightly depending on the catalyst, but is generally 50 to 450C.

Coke oven gas contains 0.1 to 2.0 volume of oxygen, and when 1.0 volume of oxygen reacts, 150C
There is a temperature rise. Further, coke oven gas contains 3.0 to 5.0 volumes of olefins, but when olefins react with 1.0 volumes, the temperature rises by 30C.

When the temperature of the hydrogenation catalyst layer exceeds 500C, -carbon oxide,
Runaway methanation reaction of carbon dioxide, carbon precipitation due to thermal decomposition of olefins, deactivation of the catalyst due to half-melting phenomenon, and damage to the reactor occur.

In order to suppress this reaction heat, it is sufficient to monitor the temperature rise of the catalyst layer and recirculate a portion of the purified gas to dilute the oxygen and olefin concentrations at the inlet.

The feed rate of coke oven gas in the hydrogenation tower is preferably 500 to 50,000 h''1 in terms of space velocity.
If it is less than 000 h", the amount of catalyst used becomes large and becomes uneconomical. If it exceeds 50000 h, the hydrogenation activity will not be sufficient. The pressure for carrying out the hydrogenation reaction may be 2 to 100 atm, but is not particularly limited. .

When hydrogen sulfide is produced by hydrogenation of a sulfur compound, it is preferably removed by a known adsorption removal method. Examples of such adsorbents include Z ” O* Fes Os and Cu
There are O, etc.

Next, a process for carrying out the present invention will be specifically explained with reference to the drawings. That is, FIG. 1 is a process diagram showing one embodiment of the present invention, where 1 means coke oven gas, 2 means adsorption tower, 3 means hydrogenation tower, and 5 means purified gas. Furthermore, FIG. 2 is a process diagram showing an embodiment of the present invention in which a part of the purified gas is recirculated to the inlet of the adsorption process, and 1 to 3 and 5 have the same meanings as in FIG. 1. Ashi, 4 means circulation line. Note that a part of the purified gas may be recirculated to the latter stage of the adsorption tower as shown by the arrow. The drawings include only the main parts (9) necessary for understanding the present invention, and other devices such as a heating furnace, a pump, a cooler, a measuring device, a control device, and other devices are omitted.

[Embodiments of the invention]

Next, the present invention will be further explained using Examples, but the present invention is not limited thereto.

Example 1 In FIG. 1, the coke oven gas 1 is about 150 to 200
It is heated to a temperature of C and introduced into the adsorption tower 2. This adsorption tower 2 has a BET surface area of 320rr? /gs is filled with alumina having an average pore volume of 0.18 mt/g.

The composition of the main components of coke oven gas is Ht: 53.72
%, Co 5.83%, Cow 2.181, CHa 30.37%, C*H4 1581, C5Ha Ka1.
58%, 02 is 0.5 (1,04H11 is 0.101,
The sulfur compound was 0.01%, the N2 was 4.13%, and the tar oil and gum substances were 10 mg 7Nm''. Alumina adsorbs and removes the tar oil and gum substances in the coke oven gas. At the outlet of the adsorption tower The amount of tar oil and gum substances in the gas is 0.1 mg/Nml (10
) and more than 99 inches of tar oil and gum substances were adsorbed and removed.

Example 2 This example shows the results of investigating the adsorption and removal performance of tar oil and gum substances when using adsorbents other than alumina. The adsorption temperature was 180C and the space velocity was 2000h-1. The results obtained are shown in Table 1.

Table 1 (11) Example 3 In this example, using alumina with a BgT surface area of 320 g, the relationship between adsorption temperature and adsorption removal performance of tar oil and gum substances was investigated at a space velocity of 5000 h-1. The results are shown in the second element.

Table 2 Example 4 The raw material coke oven gas having the composition described in Example 1 was
At a temperature of 50-200C, BET surface area 300 m/g
It is introduced into an adsorption tower filled with an alumina adsorbent having a pore volume of 0.15 mt/H. Tar oil and gum substances are almost completely adsorbed and removed.

The gas composition at the outlet of the adsorption tower is H! is 53.25 inches, CO is 5.89 inches, CO2 is 2.20 inches, CH4 is 30.67 inches.
Chi, C2H4 is 1.60 chi, C3H6 is 1.60 chi, 0
□(12) is 0.50%, C4H6 is 0.10%, and sulfur compound is 0.
01chi, N2 is 4.18chi. The gas leaving the adsorption tower is introduced into the hydrogenation tower 3 at a temperature of about 150-200C.

The catalyst for the hydrogenation tower is an alumina carrier with approximately 23% by weight of nickel supported thereon. In this treatment, dienes and oxygen in the coke oven gas are almost completely hydrogenated and removed. The purified coke oven gas leaves the hydrogenation column 3 at a temperature of 250-300C.

The composition of the main components of the purified gas 5 thus purified is H
2 is 53.52 cm, CO is 5.92% (Cot is 2.2
1 chi, C) T4 is 30.82 chi, C, H, is 1.61 chi, C5Hs is 1.61%, C4H16 is 0.101,
Sulfur compound 0.01%, N! becomes 4.20chi.

In addition, using the process shown in FIG. 2 (however, the process shown by the solid line), the amount of circulating gas is 100'j for the amount of raw coke oven gas! ! By circulating, the oxygen at the inlet of the adsorption tower was diluted, and the hydrogenation tower temperature was adjusted to a temperature of 200 to 250C.

Furthermore, by providing an adsorption tower according to the present invention, the life of the hydrogenation catalyst was dramatically improved. For example, if an adsorption tower was not installed (13), the catalyst would become unusable after about 1000 hours, but in the case of the example of the present invention, it was possible to operate without trouble for more than 4000 hours.

Example 5 The same coke oven gas as in Example 4 was treated under the same conditions and the gas exiting the adsorption tower was introduced into the hydrogenation tower at a temperature of about 150-200C. This gas uses alumina as a carrier,
It is hydrogenated using a catalyst carrying about 0.5% by weight of palladium, and impurities such as dienes, oxygen, olefins and sulfur compounds are completely hydrogenated. The composition of the main components at the hydrogenation tower outlet is 53.52% H2, 5.92% CO, 121% CO2, and 30.82% CH4.
%, CxHs 1.61%, C3H8 1.611,
C4H16 is 0.101, H2S is 0.01ch, N2
was 4.20 cm. The above generated gas is 270 to 35
It leaves the hydrogenation column at a temperature of 0C. The gas leaving the hydrogenation tower is approximately 35
The coke oven gas is introduced into a hydrogen sulfide removal column at a temperature of 0C, and hydrogen sulfide in the coke oven gas is absorbed and removed. The composition of the main components of the purified gas thus purified is H2φ! 53.53'f
i, 4) CO is 5.92%, CO2 is 2.21%, C)-I4 is 30.82%, C2H6 is 1,611%, C3l-T,
is 1.61 cm, C4Hso is 0.10%, and N2 is 4.
20%.

Example 6 The composition of the main components is 53.58 Hz and 5.9 CO.
2 yen, C02 for 2.21, CH4 for 30.86, C
Coke oven gas containing 1.60 g of 2H4, 1.60 g of C3H6, 0.01 g of sulfur compounds, 4.23 g of N2, and 10 mg/Nm of tar oil and gum matter was heated to about 150 g. Introduced into the adsorption tower at a temperature of ~200 C. In the adsorption tower, BET surface area 300 m?/gs side pore volume o
, x5 mA/g alumina adsorbent, tar oil and gum substances in the gas are almost completely adsorbed and removed.

The gas leaving the adsorption tower is heated to a temperature of about 250 to 350C in a heating furnace and then introduced into the hydrogenation tower. Olefins in the coke oven gas are converted to paraffins and sulfur compounds to hydrogen sulfide by a catalyst made of alumina as a carrier, on which about 3% by weight of cobalt and about 14% by weight of molybdenum are supported.

(15) The composition of the main components in the gas at the hydrogenation tower outlet is 53.
58%, CO 5.92%, CO2 2.21%, CH
4 is 30.86 chi, C2H6 is 1.60 chi, C5Hs is 1.60 well, I (28 is 0.01%, I'lh is 4.2
It became 2%. The gas exiting the hydrogenation tower is introduced into the hydrogen sulfide removal tower while maintaining the gas temperature at the hydrogenation tower outlet. In the tower, hydrogen sulfide in the gas is absorbed and removed. The composition of the main components of the purified gas thus purified is Hz.
．． 59%, CCl 3.92%, CO2 2.21%, C
H4 is 30.86 inches, C goose H6 is 1.60 inches, C3H8
is 1.60chi, N! became 4.22 inches.

By the process shown in Figure 2 (however, the process shown by the solid line),
By circulating the circulating gas at a rate of 100 times the amount of raw material coke oven gas, the olefins at the entrance of the adsorption tower are diluted, and the hydrogenation tower temperature is adjusted to a temperature of 300 to 400C.

According to this example, the catalyst could be used for more than 4,000 hours without any problems, but if the tar oil and gum substances were not removed using an adsorption tower, the catalyst became unusable after about 1,000 hours.

(16) [Effects of the Invention] As described above in detail, according to the present invention, tar oil and gum substances in coke oven gas are efficiently removed. When combined with a hydrogenation step using hydrogenation, the life of the hydrogenation catalyst can be greatly extended, and impurities can be efficiently removed under very mild conditions. Therefore, a remarkable effect is achieved in that each generated gas can be advantageously used for the corresponding purpose.

FIG. 1 is a process diagram showing one embodiment of the present invention, and FIG. 2 is a process diagram showing an embodiment in which a part of the purified gas is recirculated to the inlet of the adsorption process in the present invention. .

1... Coke oven gas, 2... Adsorption tower, 3... Hydrogenation tower, 4... Circulation line, 5... Purified gas.

Agent: Patent Attorney Hiroshi Nakamoto (17) Figure 1, No. 7121, 3-1-1 Saiwai-cho, Hitachi City, Hitachi Research Institute, Hitachi, Ltd. Author: Omihira Matsuda, 3-1-1 Saiwai-cho, Hitachi City Stock % Formula % No. 6 Hitachi, Ltd. (Publicant: Hitachi Ltd., Marunouchi-5-chome-1, Chiyoda-ku, Tokyo, 1-1, Procedural Amendment (Method) % Formula % Indication of Case 1981 Patent Application No. 106613Z
Title of the invention Relationship with the Coke Oven Gas Refining Method 5/Amendment Case Patent Applicant Address 2-16 Yaesu-chome, Chuo-ku, Tokyo Name Tokyo Gas Co., Ltd. Representative Hiroshi Watanabe (and one other person) 2. Amend "Method for refining coke oven gas" in the title column of the description of the amendment to "Method for refining coke oven gas."

Claims (1)

[Claims] 1. A method for purifying coke oven gas containing at least tar oil and gum substances as impurities, in which the coke oven gas is brought into contact with a porous material to adsorb and remove the tar oil and gum substances. A method for purifying coke oven gas, comprising an adsorption step. 2. The purification method includes the steps of the adsorption step and the hydrogenation step of hydrogenating impurities by catalytic hydrogenation of the coke oven gas after the adsorption step. A method for purifying coke oven gas as described in . 3. The coke according to claim 2, wherein a part of the purified gas from the hydrogenation step is recycled to the previous stage of the adsorption step, and the temperature of the hydrogenation step is adjusted so as not to exceed 450C. Furnace gas purification method. 4. The coke according to claim 2, wherein a part of the purified gas from the hydrogenation step is recycled to the latter stage of the adsorption step, and the temperature of the hydrogenation step is adjusted so as not to exceed 450C. Furnace gas purification method. 5. The coke oven gas according to any one of claims 1 to 4, wherein the porous material has a BET surface area of 10-/g or more and a pore volume of 0.10 mt/g or more. Purification method. 6. The method for purifying coke oven gas according to any one of claims 1 to 5, wherein the temperature of the adsorption step is adjusted within the range of room temperature to aooC. 7. The method for purifying coke oven gas according to any one of claims 1 to 6, wherein the porous material is selected from the group consisting of alumina, silica, activated carbon, and mixtures thereof. 8. The catalyst used in the hydrogenation step is a catalyst supporting nickel and/or cobalt, a catalyst supporting nickel and/or cobalt and molybdenum, or a catalyst supporting a platinum group metal. The method for purifying coke oven gas according to any one of items 2 to 7.