JP6575396B2 - Wet desulfurization method from hydrogen sulfide containing gas - Google Patents

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, a standard redox potential E0 is mainly used for naphthalene having two aromatic rings, anthracene having three aromatic rings, quinones having a phenanthrene skeleton, hydroquinones, or salts thereof. = 0.45 to 0.7 V 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. Although it has been carried out, all have activity equivalent to that of 1,4-naphthoquinone-2-sulfonate, which is a catalyst of the existing Takahax method.

  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

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

  In both the Takahax method and the Fumax method, a part of the desulfurization catalyst solution being recycled is extracted out of the system as a desulfurization catalyst solution in which a salt containing sulfur or ions containing sulfur is dissolved. In order to maintain the concentration of the desulfurization catalyst, it is necessary to replenish at any time. Therefore, a desulfurization catalyst is more active and a catalyst capable of exhibiting an effect even in a small amount is desired. By using a highly active desulfurization catalyst, the amount of desulfurization catalyst required to obtain sufficient activity is reduced, so the amount of replenishment can be reduced and the cost can be reduced, and the desulfurization catalyst inventory is stored. This is because the equipment and the equipment for supplying the desulfurization catalyst can be reduced in size.

  Furthermore, since both the Takahax method and the Fmax method are aqueous solutions in the form of storing and transporting the desulfurization catalyst, there is a problem that the capacity is increased and costs are incurred when storing and transporting. Had. 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.

  Although 1,2,4-trihydroxybenzene and 4-methylcatechol as discussed in Non-Patent Document 1 are sold in a solid state, the activity is comparable to that of an existing Takahax catalyst.

  In view of the above problems, the present invention provides a wet desulfurization method using a desulfurization catalyst that can be handled in a solid state, has no safety problems such as explosive properties, and has a higher desulfurization performance than a conventional desulfurization catalyst. For the purpose.

  In view of the above problems, the inventors have intensively studied a solid catalyst having no explosive properties. As a result, in the wet desulfurization method, when one or both of dimethylhydroquinone and dimethylbenzoquinone are used as the desulfurization catalyst, the desulfurization ability is already present. It was found to be higher than the Takahax catalyst.

  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 and the like, has the same activity as that of an existing Takahax catalyst, When examination was conducted with pyrogallol having only different functional group positions, it was found that sufficient activity could not be obtained. Further, it was found that sufficient activity could not be obtained even with 2,5-dihydroxy-1,4-benzoquinone in which one hydroxy group was further added to 1,2,4-trihydroxybenzene. Therefore, it was clarified that not only simple functional groups but also their positional relationship and the number of substitutions should be considered.

As a result of examining compounds having only one aromatic ring, it was found that dimethylhydroquinone or dimethylbenzoquinone has higher activity than existing Takahax catalysts. Dimethylhydroquinone or dimethylbenzoquinone has three isomers depending on the relative positional relationship of the methyl group as shown in FIG. 2, and 2,3-dimethylhydroquinone 10 or 2,5-dimethylhydroquinone 16 or 2,6-dimethyl, respectively. It is called hydroquinone 18 or 2,3-dimethylbenzoquinone 9 or 2,5-dimethylbenzoquinone 15 or 2,6-dimethylbenzoquinone 17. Any isomer has higher activity than the existing Takahax catalyst, and 2,3-dimethylhydroquinone or 2,3-dimethylbenzoquinone is particularly preferable because of its high 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 considered that the dimethylbenzoquinone 9, 15, and 17 of the oxidized form and the dimethylhydroquinone 10, 16, and 18 of the reduced form are changed.

  Therefore, even if only one of dimethylbenzoquinone and dimethylhydroquinone is used in the reaction system, the quinone group of the catalyst is repeatedly oxidized and reduced, and the oxidant and the reductant are moved back and forth. Both are present in the system, and desulfurization is considered to proceed.

  Thus, in the wet desulfurization method, it discovered that the subject of this invention could be solved by using one or both of dimethylhydroquinone or dimethylbenzoquinone 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, dimethylhydroquinone or A wet desulfurization method from a hydrogen sulfide-containing gas, wherein one or both of dimethylbenzoquinone is used.
(2) The method for wet desulfurization from a hydrogen sulfide-containing gas according to (1), wherein the dimethylhydroquinone or dimethylbenzoquinone is 2,3-dimethylhydroquinone or 2,3-dimethylbenzoquinone.
(3) The desulfurization catalyst contains at least either 2,3-dimethylhydroquinone or 2,3-dimethylbenzoquinone, and 2,3-dimethylhydroquinone, 2,3-dimethylbenzoquinone, 2,5-dimethylhydroquinone, 2 , 5-dimethylbenzoquinone, 2,6-dimethylhydroquinone, 2,6-dimethylbenzoquinone, a wet desulfurization method from a hydrogen sulfide-containing gas according to (1), which is a mixture of two or more.
(4) The wet desulfurization method from a hydrogen sulfide-containing gas according to any one of (1) to (3), wherein ammonia is used as an alkali source of the alkali solution.
(5) The desulfurization catalyst solution is produced by charging one or both of the dimethylhydroquinone and dimethylbenzoquinone into an alkaline solution in a solid state and dissolving the same. (1) to (4) The wet desulfurization method from the hydrogen sulfide containing gas of any one of Claims 1.
(6) One of or both of the dimethylhydroquinone and dimethylbenzoquinone is charged into the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst, and any one of (1) to (5) A wet desulfurization method from the hydrogen sulfide-containing gas according to item 1.
(7) 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 (6), 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.
(8) One or both of dimethylhydroquinone and dimethylbenzoquinone is added to the desulfurization catalyst solution in a solid state in the regeneration tower to replenish the desulfurization catalyst, and contains hydrogen sulfide as described in (7) Wet desulfurization method from gas.

  According to the present invention, by using one or both of dimethylhydroquinone and dimethylbenzoquinone as a desulfurization catalyst, it can be handled in a solid state, has no safety problem such as explosive properties, and has a higher desulfurization performance than a conventional desulfurization catalyst. The wet desulfurization method using the desulfurization catalyst which has this 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 a presumed reaction formula of dimethyl hydroquinone and dimethyl benzoquinone, and 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 1-8 and Comparative Examples 1-8. 1 is a schematic diagram of a desulfurization test apparatus used in Examples 9 to 11 and Comparative Examples 9 and 10. FIG.

  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 can include hydrogen, methane, carbon monoxide, carbon dioxide, 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 for bringing hydrogen sulfide into contact with a hydrogen sulfide-containing gas is obtained by dissolving one or both of dimethylhydroquinone and dimethylbenzoquinone 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 dimethylhydroquinone or dimethylbenzoquinone in water is not large, the upper limit is preferably 10 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 dimethylhydroquinone and dimethylbenzoquinone as a desulfurization catalyst, for example, 1,4-naphthoquinone compared to the case of using sodium 1,4-naphthoquinone-2-sulfonate which is a desulfurization catalyst of Takahax method The existing sales form of sodium-2-sulfonate (1 mol / L sodium salt aqueous solution) contains approximately 1 mol of sodium 1,4-naphthoquinone-2-sulfonate per kg, whereas dimethylhydroquinone powder has 7 mol per kg. Since each of the desulfurization catalyst molecules contains one active site for each molecule, the dimethylhydroquinone powder is generally available for active sites per unit weight. -Naphthoquinone-2-sulfonic acid sodium Becomes 7 times or more with respect to an anhydrous solution, it can be reduced cost of storage and transportation. From this point of view, those having a small number of rings are preferable, and dimethylhydroquinone or dimethylbenzoquinone used in the present invention has one aromatic ring, which is effective in 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 dimethylhydroquinone and dimethylbenzoquinone, which are desulfurization catalysts, do not contain alkali metal, the desulfurization catalyst solution that does not contain alkali metal exhibits the effect of desulfurization by using ammonia as the alkali source. can do. 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 24 into the desulfurization catalyst solution 5 that has absorbed hydrogen sulfide, and 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 23. The oxygen-containing gas is necessary for oxidizing dimethylhydroquinone to dimethylbenzoquinone, and air, oxygen, oxygen-enriched air, or the like can be used.

  The role of dimethylbenzoquinone, which is an oxidant of the desulfurization catalyst, and dimethylhydroquinone, which is a reductant, in the desulfurization catalyst solution will be described. When hydrogen sulfide is dissolved in an alkaline solution containing a desulfurization catalyst in the absorption tower, dimethylbenzoquinone in the desulfurization catalyst solution reacts with hydrogen sulfide to become dimethylhydroquinone. 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 is dimethylhydroquinone, 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, dimethylhydroquinone reacts with oxygen in the oxygen-containing gas to become dimethylbenzoquinone, 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 dimethylhydroquinone. 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, dimethylbenzoquinone cannot react with hydrogen sulfide, while oxygen is supplied at any time and only the reaction in which dimethylhydroquinone becomes dimethylbenzoquinone proceeds. In the desulfurization catalyst, the proportion of dimethylbenzoquinone increases. The desulfurization catalyst solution in which the proportion of dimethylbenzoquinone 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 dimethylhydroquinone or dimethylbenzoquinone, 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.

  In addition, even when multiple types of dimethylhydroquinone or dimethylbenzoquinone coexist, it is considered that each of them independently causes the reaction shown in FIG. I do not care.

  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 separately formed. As shown in FIG. 4, the hydrogen sulfide-containing gas 28 and the oxygen-containing gas 34 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 31 installed in the tower functions as an absorption tower, and the absorption process is carried out at the upper part, and the lower part of the partition wall 31 functions as a regeneration tower and the regeneration process is carried out. Above the partition wall 31, the hydrogen sulfide-containing gas 28 is blown from a position close to the partition wall 31, and the desulfurization catalyst solutions 32 and 35 in which the desulfurization catalyst being recycled is dissolved are sprayed from above, so that the hydrogen sulfide-containing gas The hydrogen sulfide in the hydrogen sulfide-containing gas 28 is absorbed by the desulfurization catalyst solutions 32 and 35, and the hydrogen sulfide-containing gas 28 from which the hydrogen sulfide has been removed is recovered as a purified gas 29 from the vicinity of the top of the column. At this time, in order to increase the contact area between the hydrogen sulfide-containing gas 28 and the desulfurization catalyst solutions 32 and 35, a filler layer is provided between the introduction portion of the hydrogen sulfide-containing gas 28 and the outlet portion of the purified gas 29 at the top of the tower. 30 may be provided. The desulfurization catalyst solutions 32 and 35 that have absorbed hydrogen sulfide are connected to the partition wall 31 via the seal pot 33, and the desulfurization catalyst solution 32 overflowing from the seal pot 33 is stored in the lower part of the tower. The oxygen-containing gas 34 is blown into the desulfurization catalyst solution 32 stored in the lower part of the tower, and the desulfurization catalyst is regenerated. The oxygen-containing gas 34 passes through the desulfurization catalyst solution 32 and is then discharged as exhaust gas 37. The desulfurization catalyst solutions 32 and 35 stored in the lower part of the tower are extracted from the lower part of the tower, and the resulting sulfur or sulfur-containing salt or sulfur-containing ions are appropriately separated and recovered, and then sent from the upper part of the tower by the liquid feed pump 36. By being introduced, it is recycled. The partition wall 31 and the seal pot 33 prevent the hydrogen sulfide-containing gas 28 and the oxygen-containing gas 34 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 24 into the stored desulfurization catalyst solution is performed, it is preferable to provide an input port 25 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 23 is the majority of the desulfurization catalyst solution circulating in the facility, and the oxygen-containing gas 24 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 39 is put into a 500 mL beaker 38, and air is blown through the cylindrical gas injection tube 41 at a rate of 0.3 L / min while stirring the solution using a magnetic stirrer 40. Carried out. The composition of the simulated reaction liquid 39 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 by the desulfurization catalyst constant, the temperature of the reaction solution was kept constant at 30 ° C. using a hot water bath 44. 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 2,3-dimethylhydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. 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 3.62 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that 2,3-dimethylhydroquinone can have a hydrogen sulfide ion treatment capacity more than twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[Example 2]
An experiment similar to Comparative Example 1 was carried out by adding solid 2,3-dimethylbenzoquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. 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 3.25 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that 2,3-dimethylbenzoquinone can have a hydrogen sulfide ion treatment capacity more than twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

Example 3
An experiment similar to Comparative Example 1 was carried out by adding solid 2,5-dimethylhydroquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. 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 3.05 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that 2,5-dimethylhydroquinone can have a hydrogen sulfide ion treatment capacity approximately twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

Example 4
An experiment similar to Comparative Example 1 was carried out by adding solid 2,5-dimethylbenzoquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. The concentration, alkali source, and reaction temperature are all the same as in Comparative Example 1. At that time, a reduction rate of 2.74 mmol·L ⁻¹ · hr ⁻¹ of hydrogen sulfide ions was obtained. This indicates that 2,5-dimethylbenzoquinone can have a hydrogen sulfide ion treatment capacity approximately twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

Example 5
An experiment similar to Comparative Example 1 was carried out by adding solid 2,6-dimethylhydroquinone in place of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. 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 3.01 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that 2,6-dimethylhydroquinone can have a hydrogen sulfide ion treatment capacity about twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

Example 6
An experiment similar to Comparative Example 1 was carried out by adding solid 2,6-dimethylbenzoquinone instead of sodium 1,4-naphthoquinone-2-sulfonate and dissolving it in the simulated reaction solution 39. 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 2.65 mmol·L ⁻¹ · hr ⁻¹ was obtained. This indicates that 2,6-dimethylbenzoquinone can have a hydrogen sulfide ion treatment capacity approximately twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

Example 7
In the same experiment as Comparative Example 1, both solid 2,3-dimethylhydroquinone and 2,3-dimethylbenzoquinone were added in place of sodium 1,4-naphthoquinone-2-sulfonate and dissolved in the simulated reaction solution 39. Carried out. The concentrations of 2,3-dimethylhydroquinone and 2,3-dimethylbenzoquinone were each 0.1 mmol / L, and the combined catalyst concentration was 0.2 mmol / L. The NaSH 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 3.40 mmol·L ⁻¹ · hr ⁻¹ was obtained. Even when both reduced dimethylhydroquinone and oxidized dimethylbenzoquinone are used at the same time, the hydrogen sulfide ion treatment capacity is more than twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. It can be demonstrated.

Example 8
In the same experiment as in Comparative Example 1, both solid 2,3-dimethylhydroquinone and 2,6-dimethylbenzoquinone were added in place of sodium 1,4-naphthoquinone-2-sulfonate and dissolved in the simulated reaction solution 39. Carried out. The concentrations of 2,3-dimethylhydroquinone and 2,6-dimethylbenzoquinone were 0.05 mmol / L and 0.15 mmol / L, respectively, and the combined catalyst concentration was 0.2 mmol / L. The NaSH 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 3.12 mmol·L ⁻¹ · hr ⁻¹ was obtained. Similarly, the concentrations of 2,3-dimethylhydroquinone and 2,6-dimethylbenzoquinone were 0.1 mmol / L and 0.1 mmol / L, respectively, and the combined catalyst concentration was 0.2 mmol / L. At that time, a hydrogen sulfide ion reduction rate of 3.34 mmol·L ⁻¹ · hr ⁻¹ was obtained. Similarly, the concentrations of 2,3-dimethylhydroquinone and 2,6-dimethylbenzoquinone were 0.15 mmol / L and 0.05 mmol / L, respectively, and the combined catalyst concentration was 0.2 mmol / L. At that time, a hydrogen sulfide ion reduction rate of 3.45 mmol·L ⁻¹ · hr ⁻¹ was obtained. Even when a mixture of a plurality of dimethylhydroquinones or dimethylbenzoquinones is used, an activity according to the concentration ratio is obtained, which is more than twice that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst. It shows that hydrogen sulfide ion processing capability can be demonstrated.

[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 indicates that sodium 1,2-naphthoquinone-4-sulfonate can only have a hydrogen sulfide ion treatment capacity equivalent to sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[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 only have a hydrogen sulfide ion treatment capacity equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[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 only have a hydrogen sulfide ion treatment capacity equivalent to that of sodium 1,4-naphthoquinone-2-sulfonate, which is a conventional Takahax catalyst.

[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]
An experiment similar to that of Comparative Example 1 was conducted by adding 2,5-dihydroxy-1,4-benzoquinone 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 0.50 mmol·L ⁻¹ · hr ⁻¹ . This indicates that 2,5-dihydroxy-1,4-benzoquinone cannot achieve the same performance as 1,4-naphthoquinone-2-sulfonate sodium, which is a conventional Takahax catalyst. -Compared with the result of trihydroxybenzene, even if it has the same functional group, it shows that there is a difference in hydrogen sulfide ion treatment ability depending on the number.

[Comparative Example 9]
The experimental apparatus is shown in FIG. The absorption tower 46 is a packed tower in which a 10 mmφ rahicilling 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, the regeneration tower 52 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 49.

The composition of the simulated gas 45 was nitrogen gas containing 10000 ppm of ammonia and 5000 ppm of hydrogen sulfide, and was blown from the bottom of the absorption tower 46 at 0.8 Nm ³ / hr. The amount of air 53 blown from the lower part of the regeneration tower 52 was 50 NL / hr. The simulated reaction solution 50 was circulated in the system by a liquid feed pump 51 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 45, and no other pH adjustment is performed.

  The concentration of hydrogen sulfide in the purified gas 47 after the treatment coming out from the upper part of the absorption tower 46 is measured by a gas chromatograph 48 with a flame photometric detector at regular intervals, 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 9
An experiment similar to that of Comparative Example 9 was performed by adding 2,3-dimethylhydroquinone 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 9. At that time, hydrogen sulfide removal rates of 100.0% and 99.4% were obtained 5 hours and 15 hours after the start of the test, respectively. This indicates that 2,3-dimethylhydroquinone 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 10]
An experiment similar to that in Comparative Example 9 was performed 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 9. 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 10
In the same experiment as in Example 9, 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 99.4. %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 11
In the same experiment as Example 9, 5 hours after the start of the test, once the simulated gas flow and 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, 553 mg of 2,3-dimethylhydroquinone was charged into the solution stored in the regeneration tower as a solid powder from the solid desulfurization catalyst inlet 54 at the top of 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 99.3% 2 hours after the restart. This indicates that the desulfurization performance is not affected even when the solid powder is added.

1, 20, 46: absorption tower, 2, 23, 52: regeneration tower, 3, 19, 28: hydrogen sulfide-containing gas, 4, 21, 29, 47: purified gas, 5, 32, 35: desulfurization catalyst solution, 6, 24, 34: oxygen-containing gas, 7, 27: desulfurization catalyst solution in which sulfur or a salt containing sulfur or an ion containing sulfur is dissolved, 8, 26, 37, 55: exhaust gas, 9: 2,3-dimethylbenzoquinone (Oxidized substance), 10: 2,3-dimethylhydroquinone (reduced form), 11: hydrogen sulfide, 12: sulfur, 13: oxygen, 14: water, 15: 2,5-dimethylbenzoquinone (oxidized form), 16: 2,5-dimethylhydroquinone (reduced form), 17: 2,6-dimethylbenzoquinone (oxidized form), 18: 2,6-dimethylhydroquinone (reduced form), 22, 36, 51: liquid feed pump, 25, 54 : Throwing of solid desulfurization catalyst Mouth, 30: filler layer, 31: partition wall, 33: seal pot, 38: 500 mL beaker, 39, 50: simulated reaction liquid, 40: magnetic stirrer, 41: cylindrical gas injection tube, 42: pH / ORP meter, 43: dissolved oxygen meter, 44: hot water bath, 45: gas containing hydrogen sulfide (simulated gas), 48: gas chromatograph with flame photometric detector, 49: circulating liquid tank, 53: air.

Claims (8)

  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, dimethylhydroquinone or dimethylbenzoquinone is used as the desulfurization catalyst. A wet desulfurization method from a hydrogen sulfide-containing gas, wherein one or both are used.   2. The wet desulfurization method from a hydrogen sulfide-containing gas according to claim 1, wherein the dimethylhydroquinone or dimethylbenzoquinone is 2,3-dimethylhydroquinone or 2,3-dimethylbenzoquinone.   The desulfurization catalyst contains at least either 2,3-dimethylhydroquinone or 2,3-dimethylbenzoquinone, and includes 2,3-dimethylhydroquinone, 2,3-dimethylbenzoquinone, 2,5-dimethylhydroquinone, 2,5- The method for wet desulfurization from a hydrogen sulfide-containing gas according to claim 1, wherein the method is a mixture of two or more of dimethylbenzoquinone, 2,6-dimethylhydroquinone and 2,6-dimethylbenzoquinone.   The wet desulfurization method from a hydrogen sulfide-containing gas according to any one of claims 1 to 3, wherein ammonia is used as an alkali source of the alkali solution.   5. The desulfurization catalyst solution according to claim 1, wherein one or both of the dimethylhydroquinone and dimethylbenzoquinone are produced by charging them into an alkaline solution and dissolving them in a solid state. A wet desulfurization method from the hydrogen sulfide-containing gas described.   6. The desulfurization catalyst is replenished by charging one or both of the dimethylhydroquinone and dimethylbenzoquinone into the desulfurization catalyst solution in a solid state. Wet desulfurization method from hydrogen sulfide-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 6, 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.   8. The hydrogen sulfide-containing gas according to claim 7, wherein one or both of dimethylhydroquinone and dimethylbenzoquinone are charged into the desulfurization catalyst solution in a solid state to replenish the desulfurization catalyst. Wet desulfurization method.

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