JP2017057293A - Wet desulfurization method from hydrogen sulfide-containing gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet desulfurization method with a desulfurization catalyst treatable in a solid state, free from safety problems such as explosibility, easily gettable at a low cost, and having desulfurization performance equal to that of the conventional desulfurization catalyst.SOLUTION: Provided is a wet desulfurization method where a desulfurization catalyst solution obtained by dissolving a desulfurization catalyst into an alkali solution is contacted with a hydrogen sulfide-containing gas to perform the desulfurization of the hydrogen sulfide-containing gas, in which, as the decarburization catalyst, either or both of methyl hydroquinone and toluquinone are used. Preferably, as the alkali source of the alkali solution, ammonia is used.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wet desulfurization method from a hydrogen sulfide-containing gas in which hydrogen sulfide is removed from the hydrogen sulfide-containing gas by a wet method, and the removed hydrogen sulfide is recovered as sulfur or a salt containing sulfur using a desulfurization catalyst.

  As a main method for removing hydrogen sulfide from a hydrogen sulfide-containing gas such as coke oven gas by a wet method, there are a Takahax method and a Fumax method. In any method, many facilities include an absorption tower 1 and a regeneration tower 2 as shown in FIG. In the absorption tower 1, the hydrogen sulfide-containing gas 3 is brought into contact with a desulfurization catalyst solution 5 in which the desulfurization catalyst is dissolved in an alkaline solution. In the regeneration tower 2, the oxygen-containing gas 6 and the desulfurization catalyst solution 5 are brought into contact with each other.

  In the absorption tower 1, by bringing the hydrogen sulfide-containing gas 3 into contact with the desulfurization catalyst solution 5, the hydrogen sulfide contained in the hydrogen sulfide-containing gas 3 is dissolved in the desulfurization catalyst solution 5, and the hydrogen sulfide is removed from the hydrogen sulfide-containing gas 3. And purified gas 4. The dissolved hydrogen sulfide is oxidized by reacting with the desulfurization catalyst dissolved in the desulfurization catalyst solution, and becomes solid sulfur or a salt containing sulfur or an ion containing sulfur. At this time, the desulfurization catalyst itself is reduced and changes from an oxidant to a reductant.

  Further, in the regeneration tower 2, the oxygen-containing gas 6 and the desulfurization catalyst solution 5 in which hydrogen sulfide is dissolved are brought into contact with each other, so that oxygen contained in the contacted oxygen-containing gas 6 is dissolved in the desulfurization catalyst solution 5 and dissolved. After the oxygen reacts with the hydrogen sulfide contained in the desulfurization catalyst solution, it reacts with the desulfurization catalyst of the reductant, returns the desulfurization catalyst to an oxidant, and regenerates the form that can react with the hydrogen sulfide dissolved in the desulfurization catalyst solution again.

  The desulfurization catalyst reacts alternately with hydrogen sulfide and oxygen dissolved in the desulfurization catalyst solution, so that the reductant and the oxidant go back and forth and are used repeatedly. The desulfurization catalyst solution 5 is repeatedly used while circulating through the absorption tower 1 and the regeneration tower 2. The generated sulfur or sulfur-containing salt or sulfur-containing ions are dissolved out of the system.

In the Takahax method described in Patent Document 1, naphthalene having two aromatic rings, anthracene having three aromatic rings, quinones having a phenanthrene skeleton, hydroquinones or salts thereof, and a standard redox potential E _A substance showing ₀ = 0.45 to 0.7V is used as a desulfurization catalyst. At this time, since the solubility in water decreases because there are two or more aromatic rings in the molecule, substances that have increased solubility in water by introducing acidic groups such as sulfonic acid and carboxylic acid Is used as a desulfurization catalyst.

  Conventionally, in the Takahax method, 1,4-naphthoquinone-2-sulfonate or a reduced form thereof is generally used as a catalyst. By repeating oxidation and reduction of the quinone group of the catalyst compound in the aqueous solution and moving back and forth between sodium 1,4-naphthoquinone-2-sulfonate and its reduced form, or ammonium 1,4-naphthoquinone-2-sulfonate The hydrogen sulfide dissolved in the desulfurization catalyst solution is made into an aqueous solution containing solid sulfur or a salt or ion containing sulfur.

  At the time when Patent Document 1 was invented, it was mainly intended for recovery with solid sulfur. However, in response to fluctuations in the market value of solid sulfur, it has recently been recovered as an aqueous solution containing salts or ions containing sulfur. Technology is becoming universal. In Non-Patent Document 1, a catalyst for facilitating recovery as an aqueous solution has been developed, and studies on 1,2,4-trihydroxybenzene having only one aromatic ring and 4-methylcatechol have been made. Has been done. 1,2,4-Trihydroxybenzene exhibits good desulfurization activity in the steady state, but is expensive and has practical problems. On the other hand, 4-methylcatechol is not only expensive but also decomposes in the air, so that it needs to be preserved in an inert gas atmosphere, which increases costs for storage and transportation.

  Further, the Fmax method of Patent Document 2 is a wet desulfurization method from a hydrogen sulfide-containing gas as shown in FIG. 1 using an aromatic polynitro compound or an aromatic polyoxy compound as a catalyst, and the desulfurization catalyst is usually picric acid. In many cases, the sulfur is recovered as an aqueous solution in which not only solid sulfur but also a salt or ion containing sulfur is dissolved.

Japanese Examined Patent Publication No. 39-001015 Japanese Patent Publication No.33-007084 JP-A-8-059600 JP 2012-25900 A

Uchida Hiroshi, Tsuru Yoshimichi, Kawada Tatsuya, Terasaki Tajiro, Kojima Yuki, Izutsu Kazuichiro, “Wet Oxidation Desulfurization with 2-Nitroso-1-naphthol-4-sulfonic acid”, Fuel Association Journal, Vol. 60, 1981, p. 58-64

  Both the Takahax method and the Fumax method had a problem in that the desulfurization catalyst was stored and transported in an aqueous solution, so that the capacity was large and the storage and transport were expensive. . Therefore, there has been a demand for a desulfurization catalyst that becomes a solid, not a desulfurization catalyst that becomes an aqueous solution when stored or transported.

  However, since picric acid, which is a desulfurization catalyst for the Fmax method, is explosive when dried and solidified, when storing and transporting a large amount of picric acid, it can be handled only in an aqueous solution for safety reasons.

  On the other hand, in the Takahax method, there is a possibility of solidification as described in Patent Document 3, but this is a method of crystallizing a solution once produced as an aqueous solution, causing a complicated process and a problem in cost. It is not manufactured at present and is difficult to obtain.

  Further, 1,2,4-trihydroxybenzene as discussed in Non-Patent Document 1 is sold in a solid state but is expensive and has a problem in practical use. 4-Methylcatechol is also expensive and decomposes in the air, so that it needs to be stored in an inert gas atmosphere, which increases costs for storage and transportation.

  In view of the above problems, the present invention provides a desulfurization catalyst that can be handled in a solid state, has no safety problems such as explosive properties, is easily available at low cost, and has a desulfurization performance equivalent to that of a conventional desulfurization catalyst. It aims at providing the used wet desulfurization method.

  In view of the above problems, the inventors have intensively studied a solid catalyst with low explosiveness. As a result, in the wet desulfurization method, when one or both of methylhydroquinone and toluquinone are used as the desulfurization catalyst, it is confirmed that the desulfurization ability is high. I found it.

  The inventors proceeded with studies on compounds that can be handled in a solid state and have few aromatic rings from the viewpoint of storage and transportation costs. In Patent Document 1, it is essential to introduce an acidic group in order to ensure water solubility. However, if the compound has only one aromatic ring in the molecule, the acidic group is particularly introduced. It turned out that it can be made into an aqueous solution without this. In addition, 1,2,4-trihydroxybenzene, which has already been confirmed to be active in Non-Patent Document 1, etc., is expensive and difficult to put into practical use from the viewpoint of cost. When examination was conducted with pyrogallol having only different group positions, it was found that sufficient activity could not be obtained. Therefore, it was clarified that not only simple functional groups but also their positional relationships should be considered.

  A compound in which one methyl group is substituted on hydroquinone or catechol can be handled in a solid state, like 1,2,4-trihydroxybenzene, and is excellent from the viewpoint of storage and transportation costs. I can say that. In Non-Patent Document 1, 4-methylcatechol has been studied, but 4-methylcatechol is an anxious compound and decomposes in the air, so that it must be stored in an inert gas atmosphere. The cost for storage and transportation increases.

Therefore, methylhydroquinone, which is a compound in which one methyl group is substituted for other hydroquinone or catechol, was examined. As a result, it was found that methylhydroquinone has sufficient activity. As shown in FIG. 2, the reaction mechanism is similar to that of the conventional Takahax catalyst. In the quinone group, reduction by dissolved hydrogen sulfide (H ₂ S) 11 and oxidation by oxygen (O ₂ ) 13 occur. It is thought that it changed into the oxidized form toluquinone 9 and the reduced form methylhydroquinone 10.

  Therefore, even if only one of toluquinone and methylhydroquinone is used in the reaction system, the quinone group of the catalyst is repeatedly oxidized and reduced, and the oxidized form and the reduced form are moved back and forth. It was also found that both existed and desulfurization proceeded.

  Moreover, methylhydroquinone is generally marketed as a solid powder and is very easy to obtain. Conventional applications include polymer raw materials, polymerization inhibitors, polymerization inhibitors, stabilizers, etc., so that market value is ensured and a relatively stable supply can be expected. Mass production is also possible, and it can be obtained at a low price at a price of 1/10 or less of 1,2,4-trihydroxybenzene and a quarter of 4-methylcatechol. In addition, toluquinone, which is an oxidized form of methylhydroquinone, can be used as a polymerization inhibitor and an oxidizing agent and is generally available, so it is also possible to obtain a desulfurization catalyst as an oxidant, making it easier to obtain a desulfurization catalyst. It is supposed to be.

  Thus, in the wet desulfurization method, it discovered that the subject of this invention could be solved by using one or both of methylhydroquinone or toluquinone as a desulfurization catalyst, and came to make invention.

(1) In the wet desulfurization method for desulfurizing the hydrogen sulfide-containing gas by bringing the hydrogen sulfide-containing gas into contact with a desulfurization catalyst solution in which the desulfurization catalyst is dissolved in an alkaline solution, methylhydroquinone or A wet desulfurization method from a hydrogen sulfide-containing gas, wherein one or both of tolquinone is used.
(2) The wet desulfurization method from a hydrogen sulfide-containing gas according to (1), wherein ammonia is used as an alkali source of the alkali solution.
(3) The desulfurization catalyst solution is produced by adding one or both of the methylhydroquinone and tolquinone into an alkaline solution in a solid state and dissolving the same, according to (1) or (2) Wet desulfurization method from hydrogen sulfide-containing gas.
(4) One or both of the methylhydroquinone and tolquinone are charged into the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst, and any one of (1) to (3) A wet desulfurization method from the hydrogen sulfide-containing gas according to Item.
(5) Using an absorption tower and a regeneration tower,
The wet desulfurization method from a hydrogen sulfide-containing gas according to any one of (1) to (4), wherein desulfurization is performed while circulating the desulfurization catalyst solution between the absorption tower and the regeneration tower. ,
In the absorption tower, by bringing the hydrogen sulfide-containing gas into contact with the desulfurization catalyst solution, the hydrogen sulfide in the hydrogen sulfide-containing gas is dissolved in the desulfurization catalyst solution, and the hydrogen sulfide-containing gas is Remove hydrogen sulfide to make purified gas,
The desulfurization catalyst solution in which the hydrogen sulfide is dissolved is circulated from the absorption tower to the regeneration tower, and in the regeneration tower, an oxygen-containing gas is brought into contact with the desulfurization catalyst solution to obtain sulfur, a salt containing sulfur, or A hydrogen sulfide-containing gas characterized by producing ions containing sulfur, recovering the sulfur, the salt containing sulfur, or the ions containing sulfur, and then circulating the desulfurization catalyst solution to the absorption tower. Wet desulfurization method from.
(6) The hydrogen sulfide-containing gas according to (5), wherein one or both of methylhydroquinone and tolquinone is charged into the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst. Wet desulfurization method from.

  According to the present invention, by using one or both of methylhydroquinone and toluquinone as a desulfurization catalyst, it can be handled in a solid state, there is no safety problem such as explosiveness, and it is easy to obtain at low cost. A wet desulfurization method using a desulfurization catalyst having desulfurization performance equivalent to that of the desulfurization catalyst can be provided.

It is a schematic block diagram of the wet desulfurization method from the hydrogen sulfide containing gas using a general desulfurization catalyst. It is an estimated reaction formula of methylhydroquinone and tolquinone with hydrogen sulfide (H ₂ S) and oxygen (O ₂ ). It is a schematic diagram of the desulfurization equipment which has a regeneration tower in which the inlet of the solid desulfurization catalyst was provided in the regeneration tower. It is a schematic diagram of the desulfurization equipment which has the function of an absorption tower and a regeneration tower. It is a schematic diagram of the desulfurization catalyst activity evaluation test apparatus used for Examples 1, 2 and Comparative Examples 1-7. It is a schematic diagram of the desulfurization test apparatus used for Examples 3-5 and Comparative Examples 8 and 9.

  Hereinafter, embodiments of the present invention will be described. As shown in FIG. 1, the wet desulfurization method of the present invention is composed of two major steps, an absorption step and a regeneration step, as in the conventional wet desulfurization method.

  The first absorption step is a step in which hydrogen sulfide contained in the hydrogen sulfide-containing gas 3 is brought into contact with the alkaline desulfurization catalyst solution 5 to dissolve the hydrogen sulfide in the desulfurization catalyst solution. Often.

  The hydrogen sulfide-containing gas 3 is an exhaust gas mainly discharged from various dry distillation furnaces, heating furnaces, power plants, etc., and is a gas containing about 10 ppm to 10000 ppm of hydrogen sulfide. Dissolution of hydrogen sulfide in an alkaline solution Because of the problem of equilibrium, a gas containing hydrogen sulfide having a somewhat high concentration can realize a higher hydrogen sulfide removal rate, and therefore, a gas containing hydrogen sulfide of 1000 ppm or more and 10000 ppm or less is more preferable. The hydrogen sulfide-containing gas may include hydrogen, methane, carbon monoxide, carbon dicarbon, nitrogen, ammonia, hydrogen cyanide, and the like in addition to hydrogen sulfide. The coke oven gas discharged from the coke oven generally contains the above-mentioned degree of hydrogen sulfide, and is a good example of a hydrogen sulfide-containing gas to which the present invention is applied.

  By bringing the hydrogen sulfide-containing gas into contact with the desulfurization catalyst solution, the hydrogen sulfide contained in the hydrogen sulfide-containing gas is dissolved in the desulfurization catalyst solution. At this time, other hydrogen cyanide contained in the hydrogen sulfide-containing gas is dissolved. The acid gas may be dissolved in the desulfurization catalyst solution, and there is no problem particularly for the purpose of simultaneously removing hydrogen cyanide.

  The desulfurization catalyst solution 5 in which hydrogen sulfide is dissolved by contacting with a hydrogen sulfide-containing gas is obtained by dissolving one or both of methylhydroquinone and tolquinone in an alkaline solution as a desulfurization catalyst. At this time, the concentration of the desulfurization catalyst is preferably 0.01 mmol / L or more in order to obtain sufficient activity. Further, since the solubility of toluquinone in water is not large, the upper limit is preferably 100 mmol / L or less.

  Furthermore, in order to absorb hydrogen sulfide from the hydrogen sulfide-containing gas, it is necessary to keep the pH of the desulfurization catalyst solution 5 alkaline. However, if the alkali is too high, the activity of the desulfurization catalyst is reduced. The pH is preferably maintained in the range of 7.5 to 11.0.

  By using one or both of methylhydroquinone and toluquinone as a desulfurization catalyst, for example, 1,4-naphthoquinone- is compared with a case where sodium 1,4-naphthoquinone-2-sulfonate, which is a desulfurization catalyst of Takahax method, is used. The existing form of sodium 2-sulfonate (1 mol / L aqueous sodium salt solution) contains approximately 1 mol sodium 1,4-naphthoquinone-2-sulfonate per kg, whereas methylhydroquinone powder contains 8 mol per kg. Since methylhydroquinone is included and each desulfurization catalyst molecule has one active site per molecule, the active site per unit weight is generally 1,4-naphthoquinone, which is generally available from methylhydroquinone powder. 2-fold sodium sulfonate aqueous solution Now, it is possible to reduce the cost of storage and transport. From this point of view, it is preferable that the number of rings is small and the number of substituents is small. One or both of methylhydroquinone and tolquinone used in the present invention has one aromatic ring, and the substituent is only one methyl group. It is effective for reducing storage and transportation costs.

  Sodium hydroxide, sodium carbonate, ammonia or the like is used as the alkali source of the alkaline solution constituting the desulfurization catalyst solution. In the present invention, since one or both of methylhydroquinone and tolquinone which are desulfurization catalysts do not contain an alkali metal, the desulfurization catalyst solution which does not contain an alkali metal exhibits its desulfurization effect by using ammonia as an alkali source. be able to. This means that, after this process, in the step of recovering sulfate ions or salts thereof from the desulfurization catalyst solution or the step of treating the desulfurization catalyst solution as a waste liquid, it is not necessary to consider the damage of the facilities due to alkali metals. It is preferable to use ammonia as the alkali source because it is advantageous because it eases operational restrictions.

  The contact method between the desulfurization catalyst solution and the hydrogen sulfide-containing gas may be a method in which a hydrogen sulfide-containing gas is inserted from the lower part of the absorption tower and the desulfurization catalyst solution is sprayed from the upper part of the absorption tower so that the desulfurization catalyst solution absorbs hydrogen sulfide. The desulfurization catalyst solution may be stored in an absorption tower, and a hydrogen sulfide-containing gas may be blown into the stored desulfurization catalyst solution, or other methods may be used. In the case of inserting the hydrogen sulfide-containing gas from the bottom of the absorption tower and spraying the desulfurization catalyst solution from the top of the absorption tower, a filler is used to increase the contact area between the hydrogen sulfide-containing gas and the desulfurization catalyst solution. It doesn't matter.

  Further, the regeneration step regenerates the desulfurization catalyst by blowing the oxygen-containing gas 20 into the desulfurization catalyst solution 5 that has absorbed hydrogen sulfide, and at the same time, the hydrogen sulfide dissolved in the solution contains sulfur or a salt containing sulfur or sulfur. This is a process of ionization, and is often performed in the regeneration tower 19. The oxygen-containing gas is necessary for oxidizing methylhydroquinone to tolquinone, and air, oxygen, oxygen-enriched air, or the like can be used.

  The role of toluquinone, which is an oxidant of the desulfurization catalyst in the desulfurization catalyst solution, and methylhydroquinone, which is a reductant, will be described. When hydrogen sulfide is dissolved in an alkaline solution containing a desulfurization catalyst in the absorption tower, toluquinone in the desulfurization catalyst solution reacts with hydrogen sulfide to become methylhydroquinone. Since the amount of hydrogen sulfide dissolved in the alkaline solution in the absorption tower is higher than the concentration of the desulfurization catalyst, most of the desulfurization catalyst in the desulfurization catalyst solution taken out from the absorption tower becomes methylhydroquinone, and the entire amount of hydrogen sulfide is treated. The liquid is sent to the regeneration tower without completing. In the regeneration tower, as described above, by blowing in the oxygen-containing gas, methylhydroquinone reacts with oxygen in the oxygen-containing gas to become tolquinone, so that it can react with hydrogen sulfide again.

  As described above, most of the desulfurization catalyst in the desulfurization catalyst solution fed from the absorption tower and introduced into the regeneration tower is methylhydroquinone. However, in the regeneration tower, the reaction with oxygen and the reaction with hydrogen sulfide are repeated to perform desulfurization. As the amount of hydrogen sulfide in the catalyst solution decreases, while toluquinone cannot react with hydrogen sulfide, oxygen is supplied at any time and only the reaction in which methylhydroquinone becomes tolquinone proceeds, so the desulfurization catalyst in the desulfurization catalyst solution The ratio of tolquinone increases in The desulfurization catalyst solution in which the proportion of tolquinone is increased is sent from the regeneration tower to the absorption tower and reused. Therefore, a part of the hydrogen sulfide in the desulfurization catalyst solution is oxidized in the absorption tower, but most of it is oxidized in the regeneration tower and becomes sulfur or a salt containing sulfur or an ion containing sulfur.

  In addition, since the mechanism is as described above, the desulfurization catalyst dissolved in the desulfurization catalyst solution may be either methylhydroquinone or tolquinone, or both. This is because, due to the reaction, each of the absorption tower and the regeneration tower settles into the above-described existence form.

  The contact method of the desulfurization catalyst solution and the oxygen-containing gas may be a method of storing the desulfurization catalyst solution in the regeneration tower and blowing the oxygen-containing gas into the stored desulfurization catalyst solution, or inserting the oxygen-containing gas from the lower part of the regeneration tower. Other methods such as a method of spraying the desulfurization catalyst solution from the upper part of the regeneration tower and absorbing the hydrogen sulfide in the desulfurization catalyst solution may be used.

  As described above, as the equipment having the absorption process and the regeneration process, the absorption tower and the regeneration tower may be formed separately. As shown in FIG. 4, the hydrogen sulfide-containing gas 24 and the oxygen-containing gas 30 to be blown are injected. If it is considered not to mix, it may be carried out with one facility having the functions of a regeneration tower and an absorption tower (see, for example, Patent Document 4).

  In FIG. 4, the upper part of the partition wall 27 installed in the tower functions as an absorption tower, and the absorption process is performed on the upper part. The lower part of the partition wall 27 functions as a regeneration tower and the regeneration process is performed. Above the partition wall 27, the hydrogen sulfide-containing gas 24 is blown from a position close to the partition wall 27, and the desulfurization catalyst solutions 28 and 31 in which the circulating desulfurization catalyst is dissolved are sprinkled from above to form the hydrogen sulfide-containing gas. 24, the hydrogen sulfide in the hydrogen sulfide-containing gas 24 is absorbed by the desulfurization catalyst solutions 28 and 31, and the hydrogen sulfide-containing gas 24 from which the hydrogen sulfide has been removed is recovered as a purified gas 25 from the vicinity of the tower top. At this time, in order to increase the contact area between the hydrogen sulfide-containing gas 24 and the desulfurization catalyst solutions 28 and 31, a filler layer is provided between the introduction portion of the hydrogen sulfide-containing gas 24 and the outlet portion of the purified gas 25 at the top of the tower. 26 may be provided. The desulfurization catalyst solutions 28 and 31 that have absorbed hydrogen sulfide are stored in the lower part of the tower via the seal pot 29 that connects the partition wall 27. The oxygen-containing gas 30 is blown into the desulfurization catalyst solution 28 stored in the lower part of the tower, and the desulfurization catalyst is regenerated. The oxygen-containing gas 30 passes through the desulfurization catalyst solution 28 and is then discharged as exhaust gas 33. The desulfurization catalyst solutions 28 and 31 stored in the lower part of the tower are extracted from the lower part of the tower and introduced from the upper part of the tower by the liquid feed pump 32, thereby being recycled. The partition wall 27 and the seal pot 29 prevent the hydrogen sulfide-containing gas 24 and the oxygen-containing gas 30 from being mixed.

  When the solid desulfurization catalyst according to the present invention is charged into the desulfurization catalyst solution in the facility, it may be dissolved in water or an alkali solution in advance to form an aqueous solution and then charged into the desulfurization catalyst solution in the facility. The solid desulfurization catalyst may be put into the desulfurization catalyst solution in the equipment as it is. When the solid desulfurization catalyst is directly added to the desulfurization catalyst solution in the facility, it is not necessary to make the solid desulfurization catalyst into an aqueous solution, which is preferable because the process can be prevented from becoming complicated.

  Since the desulfurization catalyst deteriorates or is gradually lost by extracting part of the desulfurization catalyst solution in the process of recovering sulfur or a salt containing sulfur or ions containing sulfur, It is preferable to replenish intermittently. In replenishment, the amount and timing of desulfurization catalyst addition should be determined appropriately in consideration of the amount of desulfurization catalyst solution being circulated, the components of the extracted solution, the redox potential of the desulfurization catalyst solution being circulated, etc. That's fine.

  In addition, when the solid desulfurization catalyst is charged as it is, it is necessary to provide a charging port in the facility. However, the regeneration tower and the absorption tower are formed as separate facilities. In the case of FIG. 3 in which the method of injecting the oxygen-containing gas 20 into the stored desulfurization catalyst solution is performed, it is preferable to provide an input port 21 for directly supplying the solid desulfurization catalyst to the upper part of the regeneration tower. Since the desulfurization catalyst solution stored in the regeneration tower 19 is the majority of the desulfurization catalyst solution circulating in the facility, and the oxygen-containing gas 20 is blown in, the stirring is promoted. The desulfurization catalyst can be dissolved and diffused well into the desulfurization catalyst solution.

  In addition, when the solid desulfurization catalyst according to the present invention is charged into the desulfurization catalyst solution in the facility, another catalyst may be contained in the desulfurization catalyst solution. For example, when the method of the present invention is carried out using an existing wet desulfurization apparatus, 1,4-naphthoquinone-2-sulfone, which is a desulfurization catalyst used in the conventional Takahax method, is already added to the desulfurization catalyst solution. Although an acid salt and a reduced form thereof are contained, the solution may be implemented so that the solid desulfurization catalyst according to the present invention is added to the solution.

[Comparative Example 1]
As shown in FIG. 5, 400 mL of the simulated reaction solution 35 is placed in a 500 mL beaker 34 and air is blown through the cylindrical gas injection tube 37 at a rate of 0.3 L / min while stirring the solution using a magnetic stirrer 36. Carried out. The composition of the simulated reaction solution 35 is such that NaSH has a concentration of 10 mmol / L instead of dissolved hydrogen sulfide, and 1,4-naphthoquinone-2-sulfonate sodium, which is a desulfurization catalyst of Takahax method, has a concentration of 0.2 mmol / L. It was. Since hydrogen sulfide becomes hydrogen sulfide ions when dissolved in an alkaline solution, NaSH that ionizes into sodium ions and hydrogen sulfide ions when used in an aqueous solution was used as an alternative to hydrogen sulfide. Due to the alkalinity of NaSH, the pH at the time of adjusting the simulated reaction solution 35 was in the range of 7.5 to 11.0, so the pH was not adjusted with an alkali source. In order to make the evaluation of the activity of the desulfurization catalyst constant, the temperature of the reaction solution was kept constant at 30 ° C. using a hot water bath 40. In addition, this test was a batch test, and was performed under conditions where the hydrogen sulfide ion concentration in the solution continued to decrease.

The reaction solution was sampled as the reaction time elapsed for 1 hour and 30 minutes, and the hydrogen sulfide ion concentration was measured with a capillary electrophoresis apparatus. The decrease rate of hydrogen sulfide ions was 1.50 mmol·L ^{− 1} · hr ⁻¹ was obtained. The relationship between the hydrogen sulfide ion concentration and the reaction time was approximated linearly by the least square method to determine the magnitude of the negative slope, and obtained when a similar experiment was conducted without using a catalyst from the obtained slope magnitude. The value obtained by subtracting the magnitude of the obtained slope was defined as the hydrogen sulfide ion reduction rate.

[Example 1]
An experiment similar to Comparative Example 1 was carried out by adding solid methylhydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 35. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, a reduction rate of hydrogen sulfide ions of 1.81 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that methylhydroquinone can have a hydrogen sulfide ion treatment capacity equal to or higher than sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[Example 2]
The same experiment as in Comparative Example 1 was carried out by adding tolquinone instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, a reduction rate of hydrogen sulfide ions of 1.63 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that toluquinone, which is an oxidized form of methylhydroquinone, can have a hydrogen sulfide ion treatment capacity equal to or higher than sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. It is shown that it can be used as a desulfurization catalyst even if it is put into the system in any form of a certain methylhydroquinone and an oxidized form of tolquinone.

[Comparative Example 2]
The same experiment as in Comparative Example 1 was carried out by adding hydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the reduction rate of hydrogen sulfide ions was 1.02 mmol·L ⁻¹ · hr ⁻¹ . This indicates that hydroquinone, which is one of the simplest compounds having a quinone group, cannot obtain performance equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[Comparative Example 3]
The same experiment as Comparative Example 1 was carried out by adding catechol instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the reduction rate of hydrogen sulfide ions was 0.87 mmol·L ⁻¹ · hr ⁻¹ . This indicates that catechol, which is one of the simplest compounds having a quinone group, cannot obtain performance equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[Comparative Example 4]
An experiment similar to that of Comparative Example 1 was performed with sodium 1,2-naphthoquinone-4-sulfonate instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the reduction rate of hydrogen sulfide ions was 1.46 mmol·L ⁻¹ · hr ⁻¹ . This shows that sodium 1,2-naphthoquinone-4-sulfonate can have a hydrogen sulfide ion treatment capacity equivalent to sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. However, since the amount of the active site per unit weight is 0.477 times that of methylhydroquinone, the methylhydroquinone used in the present invention can obtain the same activity as the conventional one at a lower weight.

[Comparative Example 5]
An experiment similar to that of Comparative Example 1 was performed by adding 1,2,4-trihydroxybenzene in place of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the reduction rate of hydrogen sulfide ions was 1.53 mmol·L ⁻¹ · hr ⁻¹ . This indicates that 1,2,4-trihydroxybenzene can have a hydrogen sulfide ion treatment capacity equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. However, since it is more expensive than methylhydroquinone, methylhydroquinone used in the present invention can obtain the same activity as the conventional one at a lower cost.

[Comparative Example 6]
An experiment similar to that of Comparative Example 1 was performed by adding 4-methylcatechol instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the decrease rate of hydrogen sulfide ions was 1.72 mmol·L ⁻¹ · hr ⁻¹ . This indicates that 4-methylcatechol can have a hydrogen sulfide ion treatment capacity equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. However, since it is more expensive than methylhydroquinone, methylhydroquinone used in the present invention can obtain the same activity as the conventional one at a lower cost, and 4-methylcatechol is less stable due to stability problems. It is necessary to store under an active gas atmosphere, which increases the storage cost.

[Comparative Example 7]
An experiment similar to that in Comparative Example 1 was conducted by adding pyrogallol instead of sodium 1,4-naphthoquinone-2-sulfonate. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, the decrease rate of hydrogen sulfide ions was 0.03 mmol·L ⁻¹ · hr ⁻¹ . This indicates that pyrogallol does not have the ability to treat hydrogen sulfide ions. Compared with the results of 1,2,4-trihydroxybenzene, even if it has the same functional group, hydrogen sulfide ions depend on its position. It shows that there is a difference in processing capacity.

[Comparative Example 8]
The experimental apparatus is shown in FIG. The absorption tower 42 is a packed tower in which 10 mmφ of laci-siling is put to a height of 750 mm in a glass tower having a tower diameter of 60 mm and a height of 900 mm, and the regeneration tower 48 is a glass bubble tower having a tower diameter of 80 mm and a height of 1300 mm. A cylindrical gas injection pipe was used for the gas inlet, and the effective liquid height was 1000 mm. Further, a 10 L glass bottle was used as the experimental circulating fluid tank 45.

The composition of the simulated gas 41 was nitrogen gas containing 10000 ppm of ammonia and 5000 ppm of hydrogen sulfide, and was blown from the lower part of the absorption tower 42 at 0.8 Nm ³ / hr. The amount of air 49 blown from the lower part of the regeneration tower 48 was 50 NL / hr. The simulated reaction solution 46 was circulated in the system by a liquid feed pump 47 at a flow rate of 45 L / hr. The simulated reaction solution had a sodium 1,4-naphthoquinone-2-sulfonate concentration of 2 mmol / L as a desulfurization catalyst of Takahax method, and the initial pH was adjusted to 9.0 using ammonia water as an alkali source. The alkali source after the start of the test is only ammonia contained in the simulated gas 41, and no other pH adjustment is performed.

  The hydrogen sulfide concentration of the purified gas 43 after the treatment coming out from the upper part of the absorption tower 42 is measured at regular intervals with a gas chromatograph 44 with a flame photometric detector, and the concentration of hydrogen sulfide removed in the introduced hydrogen sulfide is measured. The hydrogen sulfide removal rate as a ratio was determined. As a result, the hydrogen sulfide removal rate was 100.0% after 5 hours from the start of the test, and the hydrogen sulfide removal rate was 99.2% after 15 hours.

Example 3
An experiment similar to that in Comparative Example 8 was carried out by adding methylhydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate. The experimental equipment, concentration, alkali source, and reaction temperature are all the same as in Comparative Example 8. At that time, hydrogen sulfide removal rates of 99.8% and 99.4% were obtained 5 hours and 15 hours after the start of the test, respectively. This indicates that methylhydroquinone has a hydrogen sulfide ion treatment capacity equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[Comparative Example 9]
An experiment similar to that in Comparative Example 8 was carried out by adding hydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate. The experimental equipment, concentration, alkali source, and reaction temperature are all the same as in Comparative Example 8. At that time, hydrogen sulfide removal rates of 87.3% and 62.8% were obtained 5 hours and 15 hours after the start of the test, respectively. This indicates that hydroquinone cannot obtain the same performance as that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. This is probably because hydrogen sulfide dissolved in the alkaline solution, which is a simulated reaction solution, was not sufficiently treated by the catalyst and accumulated in the alkaline solution, and as a result, hydrogen sulfide could not be sufficiently absorbed.

Example 4
In the same experiment as in Example 3, when the composition of the simulated gas was nitrogen gas containing 12000 ppm of ammonia, 4000 ppm of hydrogen sulfide, 1000 ppm of hydrogen cyanide, carbon dioxide, 25000 ppm, and 3000 ppm of methane, the removal rate of hydrogen sulfide after 5 hours was 99.2. %Met. This indicates that hydrogen cyanide and carbon dioxide, which are other acid gases contained in coke oven gas, and methane, which is a hydrocarbon gas contained in coke oven gas, do not affect the desulfurization performance.

Example 5
In the same experiment as in Example 3, 5 hours after the start of the test, once the simulated gas flow, liquid circulation, and air blowing were stopped, 2 L of the simulated reaction liquid was withdrawn from the circulating liquid tank, and the pH was 9.0. 2 L of ammonia water diluted so as to become was added. Further, 497 mg of methylhydroquinone was charged as a solid powder from the solid desulfurization catalyst charging port 50 at the top of the regeneration tower into the solution stored in the regeneration tower. Thereafter, the circulation of simulated gas, the circulation of liquid, and the blowing of air were started again, and the hydrogen sulfide removal rate became 99.5% 2 hours after the restart. This indicates that the desulfurization performance is not affected even when the solid powder is added.

1, 16, 42: absorption tower, 2, 19, 48: regeneration tower, 3, 15, 24: hydrogen sulfide-containing gas, 4, 17, 25, 43: purified gas, 5, 28, 31: desulfurization catalyst solution, 6, 20, 30: oxygen-containing gas, 7, 23: desulfurization catalyst solution in which sulfur or a salt containing sulfur or an ion containing sulfur is dissolved, 8, 22, 33, 51: exhaust gas, 9: tolquinone (oxidant), 10: methyl hydroquinone (reduced form), 11: hydrogen sulfide, 12: sulfur, 13: oxygen, 14: water, 18, 32, 47: liquid feed pump, 21, 50: inlet of solid desulfurization catalyst, 26: Filler, 27: partition wall, 29: seal pot, 34: 500 mL beaker, 35, 46: simulated reaction solution, 36: magnetic stirrer, 37: cylindrical gas injection tube, 38: pH / ORP meter, 39: dissolved oxygen meter , 40: hot water bath, 41: containing hydrogen sulfide Scan (mock gas), 44: a flame photometric detector with a gas chromatograph, 45: circulating liquid tank, 49: air.

Claims (6)

  In the wet desulfurization method of desulfurizing the hydrogen sulfide-containing gas by bringing the hydrogen sulfide-containing gas into contact with a desulfurization catalyst solution in which the desulfurization catalyst is dissolved in an alkaline solution, one of methylhydroquinone and tolquinone is used as the desulfurization catalyst. Alternatively, a wet desulfurization method from a hydrogen sulfide-containing gas, wherein both are used.   The wet desulfurization method from a hydrogen sulfide-containing gas according to claim 1, wherein ammonia is used as an alkali source of the alkali solution.   3. The hydrogen sulfide according to claim 1, wherein the desulfurization catalyst solution is produced by charging one or both of the methylhydroquinone and tolquinone into an alkaline solution in a solid state and dissolving them. Wet desulfurization method from contained gas.   The sulfurization according to any one of claims 1 to 3, wherein one or both of the methylhydroquinone and tolquinone is added to the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst. Wet desulfurization method from hydrogen-containing gas. Using an absorption tower and a regeneration tower,
The wet desulfurization method from a hydrogen sulfide-containing gas according to any one of claims 1 to 4, wherein desulfurization is performed while circulating the desulfurization catalyst solution between the absorption tower and the regeneration tower.
In the absorption tower, by bringing the hydrogen sulfide-containing gas into contact with the desulfurization catalyst solution, the hydrogen sulfide in the hydrogen sulfide-containing gas is dissolved in the desulfurization catalyst solution, and the hydrogen sulfide-containing gas is Remove hydrogen sulfide to make purified gas,
The desulfurization catalyst solution in which the hydrogen sulfide is dissolved is circulated from the absorption tower to the regeneration tower, and in the regeneration tower, an oxygen-containing gas is brought into contact with the desulfurization catalyst solution to obtain sulfur, a salt containing sulfur, or A hydrogen sulfide-containing gas characterized by producing ions containing sulfur, recovering the sulfur, the salt containing sulfur, or the ions containing sulfur, and then circulating the desulfurization catalyst solution to the absorption tower. Wet desulfurization method from.   The wet gas from the hydrogen sulfide-containing gas according to claim 5, wherein one or both of methylhydroquinone and tolquinone is charged into the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst. Desulfurization method.

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