JP2015003291A - Biological desulfurization method, and biological desulfurization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological desulfurization method and a biological desulfurization apparatus in which desulfurization efficiency is not deteriorated even if water in which hydrogen sulfide is dissolved is used.SOLUTION: Water in which hydrogen sulfide is dissolved is sprinkled on a carrier packed layer 26 in a desulfurization tower 25 having the carrier packed layer 26 packed with a large number of carriers to which microorganism that oxidizes hydrogen sulfide is attached, the hydrogen sulfide gas is vaporized, and the sprinkled water is oxidized by the microorganism, a gas body containing hydrogen sulfide is introduced into the desulfurization tower 25, and the gas body is allowed to pass through the carrier packed layer 26, by which hydrogen sulfide contained in the gas body is oxidized by the microorganism. By supplying treated water after the oxidation treatment to a hydrogen sulfide removing part 30 that is provided for a route of the gas body after passing through the carrier packed layer 26, hydrogen sulfide which is vaporized due to sprinkling onto the carrier packed layer 26 and mixed with the gas body is removed.

Description

  Embodiments described herein relate generally to a biodesulfurization method and a biodesulfurization apparatus that desulfurize a gas body containing hydrogen sulfide by oxidation treatment using microorganisms.

  As a device for desulfurizing a gas body containing hydrogen sulfide, a desulfurization tower having a carrier packed bed packed with a carrier to which microorganisms are attached is used, and the gas body to be treated is introduced into the desulfurization tower, thereby Biological desulfurization apparatuses that desulfurize by oxidation treatment are known. In this biodesulfurization apparatus, in order to maintain the microorganisms attached to the carrier, water necessary for the organism must be sprinkled on the carrier packed bed.

  By the way, hydrogen sulfide to be treated is contained in biogas generated in a water treatment process in which organic matter is subjected to methane fermentation. When desulfurizing biogas containing hydrogen sulfide using the above-described biological desulfurization apparatus, this methane fermentation treatment is used to utilize the methane fermentation treated water treated in the above-described water treatment process as the moisture supplied to the microorganisms. Often water is used.

JP 2009-191166 A JP 2011-235234 A

  Thus, when performing biological desulfurization in which desulfurization is performed by oxidation treatment by microorganisms from a gas body containing hydrogen sulfide, if methane fermentation treated water is used as water to be supplied to microorganisms, hydrogen sulfide dissolved in methane fermentation treated water is not dissolved. There is a problem that it volatilizes in the upper part of the biological desulfurization tower and the desulfurization efficiency deteriorates.

  The problem to be solved by the present invention is to provide a biodesulfurization method and a biodesulfurization apparatus in which desulfurization efficiency does not deteriorate even when water in which hydrogen sulfide is dissolved is used.

  In the biological desulfurization method according to the embodiment of the present invention, hydrogen sulfide is dissolved in the carrier packed bed in the desulfurization tower having a carrier packed bed packed with a large number of carriers to which microorganisms that oxidize hydrogen sulfide are attached. Water is sprinkled to volatilize the hydrogen sulfide, the sprinkled water is oxidized by the microorganisms, a gas body containing hydrogen sulfide is introduced into the desulfurization tower, and the gas body passes through the support packed bed. By oxidizing the hydrogen sulfide contained in the gas body by the microorganism, the hydrogen sulfide removal section provided in the path of the gas body after passing through the support packed bed is subjected to the oxidation treatment by the microorganism. By supplying water, hydrogen sulfide volatilized by water spraying to the carrier packed bed and mixed with the gas body is removed.

  The biological desulfurization apparatus according to the embodiment of the present invention includes a desulfurization tower having a carrier packed bed packed with a large number of carriers to which microorganisms that oxidize hydrogen sulfide are attached, and hydrogen sulfide is dissolved in the carrier packed bed. A watering device for sprinkling water, a gas body containing hydrogen sulfide is introduced below the carrier packed bed in the desulfurization tower, and the gas body is passed upwardly through the carrier packed bed; Water that has been oxidized through the carrier packed bed is provided in the rising path of the gas body that has been oxidized with hydrogen sulfide, sprinkled by the watering device, descends through the carrier packed bed, A hydrogen sulfide removal section that is circulated, and the carrier packed bed oxidizes the water sprayed by the microorganisms and also oxidizes hydrogen sulfide contained in the gas body to remove the hydrogen sulfide. Part , And removing the hydrogen sulfide rises volatilized to together with the gas body than watering to the carrier filling layer.

It is a block diagram which shows schematic structure of the water treatment process which carries out the methane fermentation process of the organic substance to which the biological desulfurization apparatus which concerns on one Embodiment of this invention is applied. It is an internal block diagram which shows the biological desulfurization apparatus which concerns on the 1st Embodiment of this invention. It is an internal block diagram which shows the biological desulfurization apparatus which concerns on the 2nd Embodiment of this invention. It is an internal block diagram which shows the biological desulfurization apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a water treatment process in which a biological desulfurization apparatus 11 is applied and methane fermentation treatment of organic matter.

  In FIG. 1, a water treatment process for methane fermentation treatment is a process in which organic matter contained in water to be treated is subjected to methane fermentation treatment by a methane fermentation reactor 12 to generate biogas and treated water. Since this biogas contains hydrogen sulfide, it is introduced into the biological desulfurization apparatus 11 through the pipeline 14 together with the air pressurized by the air pump 13. And after desulfurization here, it is derived | led-out to the predetermined | prescribed post process which is not shown in figure as biogas desulfurized by the pipe line 15. FIG.

  The treated water subjected to the methane fermentation treatment is sent from the methane fermentation reactor 12 to the treated water tank 18 through the pipe line 17 and stored. A part of the treated water stored in the treated water tank 18 is supplied to the biological desulfurization apparatus 11 through the pump 19 and the pipe 20 and used as moisture to be supplied to the microorganisms as described later. Further, the remaining portion of the treated water stored in the treated water tank 18 is sent to a subsequent treatment facility (not shown) via the pump 21 and the conduit 22. Further, the drain water from the biological desulfurization apparatus 11 is introduced into the treated water tank 18 via a pipe line 23.

  Next, the configuration of the biological desulfurization apparatus 11 according to the first embodiment will be described with reference to FIG. The biological desulfurization apparatus 11 has a desulfurization tower 25 serving as a base, and a carrier packed layer 26 is provided at a lower intermediate portion in the desulfurization tower 25. The carrier packed layer 26 is filled with a number of carriers to which microorganisms that oxidize hydrogen sulfide are attached.

  A water spray mechanism 27 for sprinkling water to the carrier packed bed 26 is provided at the intermediate portion in the height direction of the desulfurization tower 25, and water is supplied to the microorganisms attached to a number of carriers constituting the carrier packed bed 26. The sprinkling mechanism 27 is connected to the pipe line 20 shown in FIG. 1, and treated water stored in the treated water tank 18 is supplied and sprinkled. This treated water is treated water from the methane fermentation reactor 12, in which hydrogen sulfide is dissolved.

  A gas introduction facility 28 is provided in the space below the carrier packed bed 26 in the desulfurization tower 25. This gas introduction facility 28 is connected to the pipe line 14 shown in FIG. 1 and introduces a gas body containing hydrogen sulfide to be treated, that is, a biogas generated from the methane fermentation reactor 12. The gas body introduced into the desulfurization tower 25 below the carrier packed bed 26 (in this embodiment, the biogas described above) passes through the carrier packed bed 26 in an upward flow and rises.

  The biogas passes through the carrier packed bed 26 in an upward flow, so that hydrogen sulfide is oxidized by microorganisms and becomes a gas body that does not contain hydrogen sulfide or has a very small amount of hydrogen sulfide. To rise. However, the water sprayed to the carrier packed bed 26 is treated water from the methane fermentation reactor 12 (hereinafter, described as treated water) in this embodiment, and hydrogen sulfide is dissolved as described above. Hydrogen sulfide is volatilized by a physical impact when the formed water comes into contact with the carrier packed layer 26. The volatilized hydrogen sulfide is mixed with the gas body that has passed through the carrier packed bed 26, diluted, and then moved up in the desulfurization tower. Further, the treated water sprayed is subjected to oxidation treatment of hydrogen sulfide dissolved by passing through the carrier packed bed 26, and is desulfurized as water containing no hydrogen sulfide or having a very small amount of hydrogen sulfide reduced. It stays in the lower part of the tower 25.

  A hydrogen sulfide removing unit 30 is provided in an upper intermediate portion in the desulfurization tower 25, that is, in a rising path of a gas body containing volatilized hydrogen sulfide. To this hydrogen sulfide removing unit 30, treated water that descends through the carrier packed bed 26 and stays in the lower part of the desulfurization tower 25 is circulated and supplied through a circulation pipe 32 having a circulation pump 31. The water to be circulated is water that does not contain hydrogen sulfide or has a very small amount of hydrogen sulfide as a result of having passed through the carrier packed bed 26 as described above.

  In this embodiment, a carrier packed bed 301 (referred to as a second carrier packed bed in this embodiment) 301 to which microorganisms that oxidize hydrogen sulfide are attached is used as the hydrogen sulfide removing unit 30, and microorganisms are formed on the upper part. A watering mechanism (referred to as a second watering mechanism in this embodiment) 302 for supplying moisture is provided. This second watering mechanism is connected to the circulation pipe 32, and the treated water staying in the lower part of the desulfurization tower 25, containing no hydrogen sulfide, or having a very small amount of hydrogen sulfide reduced to the second carrier packed bed. 301 is supplied.

  Here, the thickness of the second carrier packed layer 301 is as thin as about 10 to 50% of the thickness of the carrier packed layer (hereinafter referred to as the first carrier packed layer) 26 provided below. can do. That is, the gas body passing through the second carrier filling layer 301 functioning as the hydrogen sulfide removing unit 30 is oxidized by the first carrier filling layer 26, and the gas body almost free of hydrogen sulfide and the first carrier filling layer It is a mixture of a small amount of hydrogen sulfide sprinkled from the watering mechanism (referred to as the first watering mechanism in this embodiment) 27 for the layer 26 and volatilized from the first carrier filling tank 26. For this reason, the hydrogen sulfide concentration is significantly lower than the hydrogen sulfide concentration of the biogas introduced by the gas introduction facility 28. For this reason, as described above, the thickness of the second carrier filling layer 301 can be reduced to about 10 to 50% of the thickness of the first carrier filling layer 26.

  A pipe line 23 shown in FIG. 1 is connected to the lower part of the desulfurization tower 25 as a drain pipe. When the treated water staying in the lower part of the desulfurization tower 25 reaches a set level or higher, this excess is discharged to the drain pipe. The water is drained to the treated water tank 18 as drain water.

  Further, a processing gas pipe (processing gas pipe) 15 after biological desulfurization in the desulfurization tower 25 is connected to the upper portion of the desulfurization tower 25. A hydrogen sulfide concentration meter 35 that measures the concentration of hydrogen sulfide discharged from the desulfurization tower 25 is disposed in the processing gas pipe 15.

  In the biogas biodesulfurization apparatus having such a configuration, the hydrogen sulfide contained in the biogas introduced into the lower portion of the desulfurization tower 25 by the gas introduction facility 28 is filled with the first carrier packed bed filled in the desulfurization tower 25. By passing through 26 in an upward flow, it is oxidized by microorganisms attached to the carrier. Methane fermentation treated water is supplied from the first watering mechanism 27 to the first carrier packed bed 26. Since hydrogen sulfide is dissolved in the methane fermentation treated water, hydrogen sulfide volatilizes from the treated water. This hydrogen sulfide is oxidized in the first support packed bed 26 to remove the hydrogen sulfide, or is a second hydrogen sulfide removing device 30 disposed at the upper part in the desulfurization tower 25 together with the gas body that is greatly reduced. It flows into the carrier packed bed 301 and is oxidized by microorganisms attached to the carrier. At this time, the water sprayed from the second water sprinkling mechanism 302 contains almost no hydrogen sulfide, so that hydrogen sulfide does not volatilize due to the water sprinkling.

  As described above, by disposing the second carrier packed bed 301 on the upper part of the first watering mechanism 27, hydrogen sulfide volatilized from the methane fermentation treated water can be oxidized, so that the desulfurization efficiency in the desulfurization tower 25 is improved. To do. Further, the thickness of the second carrier packed bed 301 can be 10 to 50% of the thickness of the first carrier packed bed 26, and the initial cost can be reduced as compared with the conventional biological desulfurization apparatus. Is possible. In addition, the thickness of the 2nd support | carrier packed bed 301 shall be suitably determined according to the hydrogen sulfide density | concentration contained in methane fermentation treated water.

  Since the hydrogen sulfide concentration meter 35 is connected to the upper part of the desulfurization tower 25, the hydrogen sulfide concentration in the inflowing biogas is reduced by controlling the rotation speed of the circulation pump 31 according to the hydrogen sulfide concentration measured thereby. In this case, unnecessary power costs can be reduced.

  Next, a second embodiment shown in FIG. 3 will be described. However, the same members as those in FIG. 2 are denoted by the same reference numerals and the description thereof is omitted, and only the main parts are described. In the second embodiment, a mesh layer 303 is provided as the hydrogen sulfide removing unit 30 to form a thin film with the treated water after the oxidation treatment that is circulated. That is, as shown in FIG. 3, a mesh layer 303 is provided between the second watering mechanism 302 and the first watering mechanism 27 in the desulfurization tower 25.

  In the biogas biodesulfurization apparatus of FIG. 3, the mesh layer 303 located above the first watering mechanism 27 is supplied with water from the second watering mechanism 302 installed above the mesh layer 303 so that the thin water A film can be made.

  As described above, the hydrogen sulfide volatilized from the methane fermentation treated water supplied from the first sprinkling mechanism 27 is mixed with the gas body oxidized by the microorganisms attached to the carrier packed bed 26, so that the hydrogen sulfide concentration is increased. Low. Therefore, in some cases, the hydrogen sulfide removing unit 30 only needs to process dilute hydrogen sulfide. As in the first embodiment of FIG. 2, the installation of the second carrier packed layer 301 has an excessive processing capacity. May be secured.

  In such a case, as in the second embodiment, the mesh layer 303 can be installed as the hydrogen sulfide removing unit 30 in place of the second carrier packed layer 301 described above. The mesh layer 303 serves as a gas-liquid contact surface and captures dilute hydrogen sulfide volatilized from the methane fermentation treated water. Moisture supplemented with hydrogen sulfide falls onto the surface of the carrier packed layer 26 and is oxidized by microorganisms.

  As described above, in the second embodiment shown in FIG. 3, the mesh layer 302 is provided in place of the second carrier packed layer 301, so that an excessive processing capacity is not secured and the desulfurization in the desulfurization tower 25 is performed. Efficiency can be improved.

    Next, a third embodiment shown in FIG. 4 will be described. However, the same members as those in FIGS. 2 and 3 are given the same reference numerals, and the description thereof is omitted, and only the main parts will be described. In the third embodiment, a mist sprinkling mechanism 304 is provided as the hydrogen sulfide removing unit 30 to supply the treated water after the oxidation treatment that is circulated as mist-like moisture. That is, as shown in FIG. 4, a mist water spray mechanism 304 is provided above the water spray mechanism 27 in the desulfurization tower 25.

  The biogas biodesulfurization apparatus 11 in FIG. 4 makes it easy to capture hydrogen sulfide in moisture by supplying mist-like moisture, and the carrier packed layer 301 and the mesh layer described in the first and second embodiments. It is characterized by not providing the layer which becomes a gas-liquid contact surface like 303. That is, the third embodiment captures hydrogen sulfide volatilized from the methane fermentation treated water supplied from the sprinkling mechanism 27 by sprinkling mist-like water, and the hydrogen sulfide trapped in the mist-like water is supported by the carrier. The filling layer 26 is subjected to oxidation treatment. For this reason, initial cost and running cost can be reduced, and desulfurization efficiency in the desulfurization tower 25 can be improved.

  According to the above embodiments, the desulfurization efficiency in the biological desulfurization tower is improved, and the concentration of hydrogen sulfide discharged from the biological desulfurization tower can be reduced. Moreover, the initial cost can be reduced as compared with the conventional biological desulfurization apparatus. Furthermore, if the rotation speed of the pump is controlled according to the hydrogen sulfide concentration measured by a hydrogen sulfide concentration meter connected to the upper part of the desulfurization tower, the running cost can be suppressed.

  That is, conventionally, the hydrogen sulfide dissolved in the methane fermentation treated water is volatilized and discharged from the biological desulfurization tower when the methane fermentation treated water is sprayed from the nozzle (watering mechanism) and comes into contact with the surface of the carrier packed bed. Therefore, the desulfurization efficiency was low. In the embodiment of the present invention, a gas-liquid contact surface such as a carrier packed layer and a mesh layer and a watering mechanism are provided above the nozzle where the methane fermentation treated water is sprinkled, or water is arranged in a mist form. Since the volatilized hydrogen sulfide is dissolved in water, the hydrogen sulfide removal efficiency in the biological desulfurization tower is improved. In addition, since the water sprayed from the watering mechanism installed in the upper stage circulates the water after desulfurization, hydrogen sulfide does not volatilize from circulating water.

  Regarding the reduction of the initial cost, when the second carrier packed layer is provided on the upper stage side as the hydrogen sulfide removing section, the initial cost can be reduced by making it thinner than the first carrier packed layer on the lower stage side. This is because the role of the carrier packed bed installed on the lower side is different from that of the carrier packed bed installed on the upper side. That is, the lower carrier packed bed is intended for hydrogen sulfide generated when anaerobic fermentation of organic waste. On the other hand, the upper carrier packed bed is intended for hydrogen sulfide contained in the treated water. That is, since the hydrogen sulfide concentration passing through the upper carrier packed bed is lower than the hydrogen sulfide concentration passing through the lower carrier packed bed, the upper carrier packed layer needs to be as thick as the lower carrier packed layer. Instead, reducing the thickness of the layer leads to a reduction in initial cost.

  Furthermore, it is possible to realize further initial cost reduction by using a mesh tank or mist-like moisture in the hydrogen sulfide removing portion according to the hydrogen sulfide concentration of the gas body to be processed.

  Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Biological desulfurization apparatus 25 ... Desulfurization tower 26 ... Carrier packed bed 27 ... Water spray mechanism 30 ... Hydrogen sulfide removal part 31 ... Circulation pump 32 ... Circulation piping 301 ... Second carrier packed bed 302 ... Second water spray mechanism 303 ... Mesh Layer 304 ... Mist watering mechanism 35 ... Hydrogen sulfide concentration meter

Claims (6)

Water in which hydrogen sulfide is dissolved is sprinkled on the carrier packed bed in the desulfurization tower having a carrier packed bed packed with a large number of carriers to which microorganisms that oxidize hydrogen sulfide are attached, and the hydrogen sulfide is volatilized. Sprinkled water is oxidized by the microorganisms,
Introducing a gas body containing hydrogen sulfide into the desulfurization tower, and passing the gas body through the support packed bed, oxidizing hydrogen sulfide contained in the gas body by the microorganisms,
By supplying water after oxidation treatment by the microorganisms to the hydrogen sulfide removal section provided in the path of the gas body after passing through the carrier packed bed, the gas is volatilized by sprinkling water into the carrier packed bed. Remove hydrogen sulfide mixed with the body,
A biodesulfurization method characterized by the above. A desulfurization tower having a carrier packed bed packed with a number of carriers to which microorganisms for oxidizing hydrogen sulfide are attached;
A watering device for sprinkling water in which hydrogen sulfide is dissolved in the carrier packed bed,
A gas introduction facility for introducing a gas body containing hydrogen sulfide below the support packed bed in the desulfurization tower, and allowing the gas body to pass through the support packed bed in an upward flow;
Water that is provided in the rising path of the gas body oxidized with hydrogen sulfide by passing through the carrier packed bed, sprinkled by the sprinkler, descends through the carrier packed bed, and oxidized with hydrogen sulfide. And a hydrogen sulfide removal section that is circulated and supplied,
The carrier packed bed oxidizes the sprinkled water by the microorganisms and oxidizes hydrogen sulfide contained in the gas body, and the hydrogen sulfide removing unit volatilizes from the water sprayed onto the carrier packed bed. And removing hydrogen sulfide rising together with the gas body,
A biological desulfurization apparatus characterized by that.   The biological desulfurization apparatus according to claim 2, wherein a second carrier packed bed to which microorganisms that oxidize hydrogen sulfide are attached is used as the hydrogen sulfide removal unit.   The biodesulfurization apparatus according to claim 2, wherein a mesh layer for forming a thin film is provided as the hydrogen sulfide removing section with water after the oxidation treatment that is circulated.   The biological desulfurization apparatus according to claim 2, wherein the hydrogen sulfide removing unit uses a mist spraying mechanism that sprays the water after the oxidation treatment that is circulated and supplied in a mist form.   A hydrogen sulfide concentration meter that measures the hydrogen sulfide concentration of the gas body desulfurized by the desulfurization tower is provided, and after the oxidation treatment that is circulated and supplied to the hydrogen sulfide removal unit according to the measurement value of the hydrogen sulfide concentration meter The biological desulfurization apparatus according to any one of claims 2 to 5, wherein the flow rate of water is adjusted.

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