KR100762715B1 - Desulfurization and catalyst regeneration apparatus and method thereof - Google Patents

Abstract

A method and an apparatus for desulfurizing digested gas and reproducing catalysts are provided to decrease the consumption amount of catalysts, by continuously reproducing oxidizing catalysts used in a desulfurizing process. A sulfur compound receiving process is performed by receiving in a first reactor from an anaerobic digestion bath(S10). A pretreating process is performed by previously desulfurizing the received sulfur compound(S20). A reactive gas receiving process is performed by receiving the desulfurized reactive gas in a second reactor(S30). A desulfurizing process is performed by removing the sulfur compound from the received reactive gas through catalysts(S40). Desulfurizing catalysts used in the pretreating process and the desulfurizing process are collected(S50). The desulfurized catalysts are reacted with oxidizing agents consisting of at least one of air, oxygen, ozone, and peroxide so that the desulfurized catalysts are reproduced(S60). A desulfurizing catalyst recirculating process is performed so that the reproduced catalysts are transferred and supplied for the pretreating process and the desulfurizing process(S70).

Description

Exhaust gas desulfurization and catalytic regeneration device and method thereof {DESULFURIZATION AND CATALYST REGENERATION APPARATUS AND METHOD THEREOF}

The present invention relates to a digestion gas desulfurization method and apparatus, and a catalyst regeneration method and apparatus, and more particularly, to a desulfurization method and apparatus for efficiently removing sulfur compounds in an anaerobic digestion tank by using a liquid oxidation catalyst. A catalyst regeneration method and apparatus for reducing catalyst consumption by continuously regenerating an oxidation catalyst used in the present invention.

Desulfurization methods to remove sulfur compounds in the anaerobic digester which are generally used are divided into dry absorption method and wet absorption method.

The dry absorption method removes sulfur compounds by contact with solid adsorbents such as iron oxide (Fe ₂ O ₃ ) and activated carbon, which is excellent in adsorption at low temperatures and low humidity, but generates excessive heat when processing high concentrations of materials. If the temperature is high, the adsorption performance is remarkably reduced, and when the gas is treated with high humidity, the adsorption efficiency is drastically reduced due to the adsorption disturbance or channeling phenomenon due to moisture.

In the wet absorption method, a gas and a liquid (absorbent) come into contact with each other in countercurrent or cocurrent flow through a washing apparatus to remove sulfur compounds, and a caustic soda method and a liquid oxidation method exist as commercialization technologies. The caustic soda method is the oldest technology, and it is one of the most popular technologies in the past because it is easy to operate and has excellent performance. However, the cost of disposal of spent caustic soda after use is high and the excess of caustic soda Due to the excessive operation cost and excessive alkali alkali pegasic soda generation, it is classified as an unfriendly environment, and the supply of technology is stopped in the developed countries.

Therefore, there is a need for a desulfurization means that can environmentally remove sulfur compounds in the anaerobic digester and increase the removal efficiency, and the desulfurization cost for removing sulfur compounds is considerable, which hinders commercialization.

The present invention is to solve the above problems by removing the sulfur compounds of the anaerobic digestion tank by the liquid oxidation reaction catalyst to activate the oxidation catalyst action of sulfur compounds contained in the first reactor and then harmless sulfur compounds by the oxidation catalyst in the secondary reactor It is an object of the present invention to provide a method and apparatus for desulfurization of a digestive gas which is converted to odorless sulfur to reduce sulfur compounds.

In addition, the desulfurization catalyst used in the first or the secondary reactor is recovered to the regeneration process unit to provide a continuous regeneration reaction to the oxidant and then recycled to the first and second reactors to provide a catalyst regeneration method and apparatus for recycling. Is in.

In the present invention, in order to achieve the above object, the digestion gas desulfurization method removes sulfur compounds of an anaerobic digestion tank using a liquid oxidation reaction catalyst, but in the main reactor (secondary reactor), sulfur compounds introduced into the anaerobic digestion tank in a pretreatment step. It is characterized in that the reaction gas is pre-reacted with the used oxidation catalyst and then the reaction gas is transferred to the main desulfurization step, and the main desulfurization step allows the pre-reacted reaction gas to finally remove the sulfur compound by the oxidation catalyst.

In addition, in the digestion gas desulfurization apparatus according to the present invention, in order to pre-react the reaction gas flowing into the anaerobic digestion tank, an oxidation catalyst used and regenerated in the main reactor (secondary reactor) is introduced and the reaction gas is secondary. A primary reactor composed of a configuration for transferring to the reactor; A secondary reactor comprising desulfurization by removing the sulfur compound by an oxidation catalyst supplied from the catalyst supply unit by the reaction gas introduced from the primary reactor and discharging the desulfurized gas into the gas discharge unit; It consists of; a catalyst supply unit for supplying a total solvent mixture of the catalyst and water.

In addition, the catalyst regeneration method and apparatus using the digestive gas desulfurization apparatus, by the reaction of the oxidizing catalyst recovered from the primary or secondary reactor by the oxidizing agent is regenerated and recycled to the first and second reactors to recycle It consists of a reproducing method and apparatus to make it happen.

In the present invention, the sulfur compound of the anaerobic digestion tank is desulfurized by using a catalyst previously used in the first reactor, and then the sulfur compound is converted into harmless and odorless sulfur by an oxidation catalyst in the second reactor to reduce the sulfur compound. It will be possible to maximize the desulfurization efficiency.

In addition, since the desulfurization catalyst used in the primary or secondary reactors is regenerated by the oxidizing agent and then recycled to the primary and secondary reactors, it can be recycled, thereby reducing the catalyst consumption.

Exhaust gas desulfurization method using the liquid oxidation catalyst in the present invention to efficiently remove the sulfur compounds in the anaerobic digestion tank is as follows.

The present invention is a sulfur compound receiving step (S10) for receiving the sulfur compound introduced into the anaerobic digester in the primary reactor (10), and a pre-treatment step for the prior desulfurization reaction using the catalyst used in the secondary main reactor (S20); Reaction gas receiving step (S30) for receiving the pretreated reaction gas in the secondary reactor (30); Desulfurization step (S40) for removing the sulfur compound by the oxidation catalyst in the accommodated reaction gas; characterized in that to be able to remove the sulfur compound.

In the pretreatment step (S20), sulfur compounds such as hydrogen sulfide (H ₂ S) and mercaptan (R-SH) introduced into the anaerobic digester gas are first desulfurized using an oxidation catalyst used in the main reactor, followed by a main desulfurization step. Reaction gas transfer is carried out in the main desulfurization step (S40) to remove the sulfur compound as desired by the oxidation catalyst to the pretreated reaction gas.

Liquid phase oxidation catalysts used in the first and second reactors 20 and 30 are solid alkaline earth metal oxides such as magnesium oxide (MgO), calcium oxide (CaO), tin oxide (SrO) and barium oxide (BaO). In which at least one component selected from the group consisting of transition metals iron, zinc, molybdenum, manganese, copper and oxides thereof is supported on the support, in the group consisting of alkali metal hydroxides and iron chelates At least one shall be included.

The supported amount of the transition metal or its oxide is used in the range of 0.1 to 50% by weight based on the total solid catalyst.

The desulfurization catalyst according to the present invention is referred to as C, and the reaction between the desulfurization catalyst in water and the sulfur compound in the digester gas is as follows.

As in the reaction, a desulfurization catalyst is used to convert sulfur compounds such as hydrogen sulfide and mercaptan into harmless elemental sulfur.

In the above reaction, since oxygen is used to regenerate the catalyst, it is applied to a catalyst regeneration device for supplying oxidants such as oxygen, air, ozone, and hydrogen peroxide to the desulfurization catalyst slurry, thereby improving the performance and lifetime of the catalyst by sulfur compounds.

The anaerobic digester gas contains siloxane (Siloxanc) and various volatile organic compounds (Volatile Organic Compounds) in addition to the sulfur component to accelerate the catalyst deactivation by the phenomenon that they cover the catalytic active surface. Electron microscopy observed that a polymeric material, such as siloxane, covered the surface of the catalyst. Therefore, by regenerating the catalyst in the main reactor after the regeneration, the catalyst of the part discharged to the waste catalyst is sent to the first pretreatment process to delay the catalyst deactivation by polymer foreign substances such as siloxane and to a certain amount (about 30 to 50). By removing the sulfur compound of%), it increases the reaction efficiency in the main reactor and maximizes the utilization of catalyst, which can drastically reduce the amount of catalyst used.

In addition, the digestion gas desulfurization apparatus according to the present invention is connected to the anaerobic digestion tank (10), the sulfur compound inlet pipe (21) for receiving and desulfurizing sulfur compounds in the anaerobic digestion tank (10), the catalyst for the injection of the oxidation catalyst is made An injection tube 22 and a gas transfer pipe 23 for transferring the first desulfurized reaction gas to the secondary reactor 30 to extend the overall reaction efficiency and catalyst life, and ; The primary reactor 20 receives the reaction gas introduced through the gas transfer pipe 23, the catalyst injection pipe 31 for removing the sulfur compound by the injection of an oxidation catalyst, and the discharge of the gas from which the sulfur compound is removed. A secondary reactor 30 provided with a gas discharge pipe 32 for this purpose to remove sulfur compounds by an oxidation catalyst; It is connected to the secondary reactor 30 and the catalyst transfer pipe 41, the catalyst supply unit 40 for supplying a catalyst solution in the liquid state mixed with the catalyst and water;

One side of the upper primary reactor 20 is connected to the filter transfer pipe 61 is provided with an on-off valve is connected to the filter 60 to separate the waste water and the catalyst filtered through the filter 60 separately.

The primary reactor 20 and the secondary reactor 30 in the above are selected and used among scrubbers, slurry reactors, packed columns, or sieve plate type reactors.

In the desulfurization apparatus having the above-described configuration, the desulfurization reaction is performed by utilizing the catalyst used in the primary reactor 20 in advance to maximize the removal of sulfur compounds by the oxidation catalyst in the secondary reactor 30. It becomes possible.

And digestive gas catalyst regeneration method of the present invention, sulfur compound receiving step (S10) and; A pretreatment step (S20) of the prior desulfurization reaction; Receiving the pretreated reaction gas (S30); The received reaction gas desulfurization step (S40) and; Recovering the liquid / solid desulfurization catalyst used in the pretreatment and desulfurization step (S50); A desulfurization catalyst regeneration oxidation step (S60) for reacting the desulfurization catalyst with an oxidizing agent to perform regeneration; Recycling of the catalyst is achieved; a recirculation supply step (S70) for transporting the regenerated desulfurization catalyst to the pretreatment step and the desulfurization step.

The oxidizing agent used above corresponds to air, oxygen, ozone, hydrogen peroxide and the like.

The desulfurization catalyst slurry is a mixture of the desulfurization catalyst and water, the desulfurization catalyst slurry can be operated with a variety of catalyst content depending on the concentration of the sulfur compound to be treated, and is generally operated with a catalyst content of 0.2 ~ 0.5%. The operating conditions are basically room temperature and atmospheric pressure, and the reaction and regeneration efficiency increase only when the solubility of the gas is high.

Extinguishing gas catalyst regeneration device, the first reactor 20 and the same as the desulfurization device; Secondary reactor 30 and: the catalyst supply unit 40 is made of the same components, but the regeneration recovery pipe 51 for allowing the desulfurization catalyst used in the primary 20 or secondary reactor 30 is recovered and accommodated ), An oxidant supply pipe 52 for supplying an oxidant, and a recycle supply pipe 53 for supplying the regenerated desulfurization catalyst to the primary and secondary reactors 20 and 30 are provided to recycle the desulfurization catalyst. Regeneration process unit 50; consists of.

In the secondary reactor 30, the desulfurization catalyst is transferred to the primary reactor 20 and the regeneration process unit 50 through the branch pipe 33, respectively.

By the above configuration, since the desulfurization catalyst is regenerated and recycled, the catalyst usage can be greatly reduced.

 Hereinafter, the present invention will be described in more detail with reference to the following Examples.

< Comparative Example  1>

In Comparative Example 1, hydrogen sulfide (H ₂ S) desulfurization performance using only a secondary reactor using a powder-shaped 6% iron / manganese oxide (Fe / MgO) catalyst, and hydrogen sulfide using a secondary reactor and a regeneration process Desulfurization performance is compared. The total flow rate of gas (N ₂ ) was 35 L / min and the hydrogen sulfide concentration was 1000 ppm. The amount of catalyst used was 0.3%, and a batch was used to measure hydrogen sulfide desulfurization performance and catalyst life.

The hydrogen sulfide desulfurization performance using only the secondary reactor was only 2.3 hours when the desulfurization efficiency was maintained above 90%, but the desulfurization performance using the secondary reactor and the regeneration process was 14 hr. At this time, the oxidant used in the regeneration process was air. The catalyst life was also found to be 6.2 times better for the process consisting of the secondary reactor and the regeneration process. The results are shown in FIG. 4 and Table 1 below.

( Table 1). Using secondary reactor, secondary reactor and regeneration process

        Desulfurization Performance and Catalyst Consumption Comparison

Item Secondary reactor (Exclusive) Reactor / Regeneration Process (Oxidizer: Air ) H ₂ S Desulfurization Performance  2.3hr  14hr Catalyst consumption  6.2  1 (standard)

* Based on 90% removal rate

< Comparative Example  2>

In Comparative Example 2, the H ₂ S desulfurization performance and the catalyst consumption were compared when the secondary reactor and the primary and secondary reactors (FIG. 3) were used simultaneously. The reaction conditions used for the two experimental groups are the same as in Comparative Example 1. This experiment is to transfer the regenerated (partially discharged) catalyst from the secondary reactor of the primary and secondary reactor process to the primary reactor to maximize the catalytically active components. The results are shown in Table 2 below. As shown in Table 2, the desulfurization performance of 2.5 hours after the start of the reaction increased the removal rate up to 98% when the first pretreatment reactor was used and the catalyst life increased about 50%.

Table 2. Comparison of Desulfurization Performance and Catalyst Consumption Using Secondary Reactor and Primary and Secondary Reactor

Item Secondary reactor (Exclusive) One· Secondary reactor Primary reactor Secondary reactor H2S Desulfurization Performance (2. 5 hours later  88%  50%  Final 98% Catalyst consumption (2. 5 hours later )  1.5  1 (standard)

< Comparative Example  3>

In Comparative Example 3, the hydrogen sulfide desulfurization performance in the digester gas was compared by using a secondary reactor and a primary and secondary reactor (continuous type) installed in the field. The treated gas flow rate was 100 m ³ / hr or more and the hydrogen sulfide injection concentration was 800 ppm. However, because there was no regeneration process in the field, the catalyst used in the secondary reactor was not regenerated and injected directly into the primary pretreatment reactor, and the results are shown in Table 3. As shown in the table, the performance of the primary and secondary reactors was 15% higher than that of the secondary reactor alone. The catalyst life was also about 20% better than the simultaneous use of primary and secondary reactors.

Table 3. Using the Secondary Reactor and the First and Secondary Reactors at the Digester Site

      Desulfurization Performance and Catalyst Consumption Comparison

Item Secondary reactor (Exclusive) Primary and Secondary Reactors H ₂ S Desulfurization Performance  75% ~ 80%  93% ~ 95% Catalyst consumption  1.2  1 (standard)

< Comparative Example  4>

 In Comparative Example 4, the case where the secondary reactor was treated alone was compared with the case where the primary and secondary reactors and the regeneration process were used, and the results are shown in Table 4. Gas, catalyst injection, and other conditions are the same as in Comparative Example 1. When only the secondary reactor was used as in Comparative Example 1, the performance was maintained at 90% or more, only 2.3 hours, and the catalyst consumption was also large. The performance was much better than the operation of the secondary reactor alone, so the removal time of more than 90% was recorded for more than 22 hours. It can be seen that the catalyst life is also increased more than nine times.

Table 4 . Comparison of Removal Performance and Catalyst Consumption Using Secondary Reactor, Primary and Secondary Reactors, and Regeneration Process

Item Secondary reactor (Exclusive) Reactor / Regeneration Process Figure 2 ) Air  20L / min H ₂ S Desulfurization Performance  2.3hr  22hr Catalyst consumption  9.1  1 (standard)

In the above, the present invention has been described with reference to the above embodiment, but various modifications can be made within the technical scope of the present invention.

1 is a block diagram showing a desulfurization and catalyst regeneration apparatus according to the present invention

2 is a block diagram of a catalyst regeneration apparatus in which the present invention is not equipped with a primary reactor

3 is a block diagram of a desulfurization apparatus not provided with the catalyst regeneration apparatus of the present invention

4 is a performance comparison graph according to Comparative Example 1 of the present invention

5 is a performance comparison graph according to Comparative Example 4 of the present invention

Figure 6 is a block diagram showing a desulfurization process of the present invention

7 is a block diagram showing a catalyst regeneration process of the present invention.

* Explanation of symbols for main parts of the drawings

10: digester 20: primary reactor

30: secondary reactor 40: catalyst supply unit

50: Regeneration Process

Claims (9)

delete delete delete delete delete Sulfur compound receiving step (S10) for receiving the sulfur compound introduced into the anaerobic digester in the first reactor;  A pretreatment step (S20) of preliminary desulfurization of the sulfur compound received; A reaction gas accommodating step of receiving the pretreated reaction gas in a secondary reactor (S30); Desulfurization step (S40) for removing the sulfur compound by the oxidation catalyst to the received reaction gas; Recovering the liquid / solid desulfurization catalyst used in the pretreatment and desulfurization step (S50); A desulfurization catalyst regeneration oxidation step (S60) of reacting the desulfurization catalyst with an oxidizing agent consisting of at least one of air, oxygen, ozone, and hydrogen peroxide to perform regeneration; The desulfurization catalyst recycling and supplying step (S70) to transfer the regenerated desulfurization catalyst to the pretreatment step and the desulfurization step (S70) . delete delete A sulfur compound inlet tube 21 for receiving and desulfurizing sulfur compounds in the anaerobic digester 10 connected to the anaerobic digester 10, a catalyst inlet tube 22 for injecting an oxidation catalyst, and preliminary desulfurization A primary reactor 20 having a gas transfer pipe 23 for transferring the reacted reaction gas to the secondary reactor 30; The primary reactor is configured to receive the reaction gas introduced through the gas transfer pipe 23, the catalyst injection pipe 31 for removing the sulfur compound by the injection of the oxidation catalyst, and the discharge of the gas from which the sulfur compound is removed A secondary reactor 30 provided with a gas discharge pipe 32 for removing sulfur compounds by an oxidation catalyst; A catalyst supply unit 40 connected to the secondary reactor 30 and the catalyst transfer pipe 41 to supply a catalyst solution in a liquid state in which a catalyst and water are mixed; The regeneration recovery pipe 51 for allowing the desulfurization catalyst used in the primary 20 or the secondary reactor 30 to be recovered and received, the oxidant supply pipe 52 for supplying the oxidant, and the regenerated desulfurization catalyst Digestion gas desulfurization and catalyst regeneration, characterized in that consisting of; regeneration process unit 50 is provided with a recirculation supply pipe 53 for supplying to the primary and secondary reactors 20, 30; Device.

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