JP2006111753A - Organic material-containing gas-treating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic material-containing gas-treating system which can remove tar odor in waste water. <P>SOLUTION: The system is equipped with a dust-removing apparatus 201 for removing dust in a formed gas 66, which is the organic material-containing gas, by a water jet scrubber 4, a strainer 17 which is a floating-separation apparatus for removing a fine particle component from the waste water 201a having cleared dust by means of the water jet scrubber 4 in the dust-removing apparatus 201, and a stripping column 211 for removing a tar component in the waste water taken out from a part of a circulating water 201b having cleared the fine particle component by the strainer 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic substance-containing gas processing system that processes gas gasified using, for example, biomass, and more particularly to a technique that can remove a tar odor in waste water.

For example, various systems have been developed that produce steam gas by using a combustible material such as biomass to produce liquid fuel such as methanol. An example is shown in FIG.
As shown in FIG. 4, an example of a methanol synthesis system using biomass, which is a typical example of organic fuel, is shown.

  Biomass generally refers to organisms that can be used as energy sources or industrial raw materials (for example, agricultural products or by-products, wood, plants, etc.), and are produced by the action of solar energy, air, water, soil, etc. So it can be played indefinitely.

By using the biomass, it is possible to produce a clean energy source such as fuel gas and methanol. Since it treating biomass as waste, along with also help clean environment, since biomass is produced newly it is also grown by fixation of CO ₂ by photosynthesis, no increase of CO ₂ atmosphere, CO ₂ This is a preferable technique because it leads to suppression of the problem.

  As shown in FIG. 5, the liquid fuel production system includes a biomass supply means 62 for supplying biomass 60 into a gasification furnace 61, and a combustion oxidant 63 made of oxygen or a mixture of oxygen and water vapor. A biomass gasification furnace 65 provided with an oxidant supply means 64 for supplying inside, a cyclone 67 for removing dust in the product gas 66 gasified by the biomass gasification furnace 65, and the cyclone 67 of 3 μm or more A dust removing device 11 for removing dust with a relatively large particle size from the dust removed with higher accuracy, a gas purification device 68 for purifying the gas removed with high accuracy, and methanol using the purified gas. And a methanol synthesizer 71 equipped with a distillation device that separates the exhaust gas 69 and the methanol 70 into methanol, which is a liquid fuel from biomass. It is to be formed.

  Here, as the biomass 60 to be supplied, it is preferable to supply pulverized and dried biomass produced or discarded. Biomass referred to in the present invention refers to biological resources (for example, agricultural products or by-products, wood, plants, etc.) that can be used as an energy source or industrial raw material. For example, sweet sorghum, napiergrass, spirulina, etc. are used. It has been.

  Since the gas generated from the biomass contains fine particles, tar components, hydrogen sulfide, chlorine, cyan, heavy metal compounds, etc., as it is, it can be used as a liquid fuel using a synthetic catalyst or as an energy source for fuel cells. Not suitable for gas for synthesis. Therefore, conventionally, trace components such as the fine particles, tar components, hydrogen sulfide, and chlorine are efficiently removed using the dust removing device 11 using a water jet water droplet jet.

  In the liquid fuel production system, the generated gas contains fine dust-like dust components. When these gases are used as a raw material gas for synthesizing liquid fuel, it is necessary to carry out a process for removing dust in the gas with high accuracy.

  As the above-described gas dust removing device, a device using a water jet water droplet jet as a removal medium has been known (Patent Document 1), and various improvements have been proposed depending on the processing target. Among them, a representative example is shown in FIG.

  As shown in FIG. 6, the dust removing device 11 using the water jet water droplet jet sucks a gas 101 that requires dust removal processing to form a water jet water droplet jet 102 in the vertical axis direction, and the drive nozzle. The water jet water droplet jet 102 and the gas 101 are gas-liquid mixed by being received so as to cover the water jet water droplet jet 102 discharged from the driving nozzle 103, and dust particles in the gas are attached to the water droplet. The cylindrical scrubber unit 104 for removing dust from the gas 101 and the water jet water droplet jet water stored as circulating water and the gas 101 from which the fine particle component and the water-soluble component are separated in the scrubber unit 104 are stored. A circulating water tank 105 having a discharge port 105a to be sent to the next processing step, and storage in the circulating water tank 105 An agitating means 106 for agitating the circulating water tank 105, a discharge pipe 108 forcibly discharging the circulating water in the circulating water tank 105 by the circulation pump 107, and an interposition in the exhaust pipe 108. The strainer 109 is provided.

  The scrubber portion 104 is an integrally structured tubular member, and has a chamber portion 104a having a relatively large diameter, followed by a funnel-shaped suction portion 104b, a reduced diameter straight tubular throat portion 104c, and a diffuser that gradually increases in diameter. It is comprised from the part 104d and the wide outlet straight pipe | tube exit pipe | tube part 104e which has the opening 104. FIG. The drive nozzle 103 is disposed in the center of the chamber portion 104 a, and the jet nozzle of the drive nozzle 103 is located at the center line of the scrubber portion 104. An inlet 104f for the gas 101 is formed on the side of the chamber portion 104a, and the gas 101 is set to be entrained in the water jet water droplet jet 102. The water jet water droplet jet 102 and the gas 101 merge at the suction portion 104b, and gas-liquid mixing is performed at a high flow velocity in the reduced diameter straight tubular throat portion 104c, thereby promoting adhesion and coalescence of dust particles to the water droplets. Thereafter, the water droplet jet is guided to the diffuser portion 104d, which gradually expands in diameter, and the flow velocity decreases, and the high flow velocity energy is changed to pressure energy to reduce the pressure loss of the scrubber. The water droplet flow in which the fine particle component and the water-soluble component are absorbed from the gas 101 flows into the circulating water tank 105 at a low speed from the outlet pipe portion 104e having a widened straight tube, and the gas 101 washed with water is supplied to the circulating water tank 105. The gas is discharged from the gas discharge port 105a to the next processing step via the upper space.

  Dust and tar components separated from the gas 101 by the water jet water droplet jet 102 and attached to the water droplets are temporarily submerged in the water by dropping together with the water droplets in the circulating water tank 105, but are hydrophobic and lightweight. Because there is, it rises to the surface of the water immediately. Even when the water droplet jet water continues to flow strongly, the fine particle component cannot be uniformly distributed in the circulating liquid. Therefore, even if the circulating fluid is sucked from the discharge pipe disposed below the circulating water tank 105, the floating fine particle component can hardly be recovered. Therefore, in this apparatus, a stirring means 106 that stirs the water in the circulating water tank 105 is provided. By driving the stirring means 106, the water staying in the water is prolonged by the water flowing down vigorously as described above, and the circulation pump 107 is connected to the water through the discharge pipe 108 together with the circulating water. And then separated and recovered by the strainer 109. The water from which the fine particle component is separated by the strainer 109 is sent from the circulation pump 107 to the drive nozzle 103 by the circulation line 110, and a part of the water is discharged as drainage 100 to the outside.

  The circulation line 110 is provided with a heat exchange type cooler 111 and an on-off valve 112 and a flow meter 113. Further, a bypass pipe 114 is connected to the downstream side of the cooler 111 in the circulation line 110 so as to send a part of the circulating water directly into the circulating water tank 105. An open / close valve 115 and a flow meter 116 are also attached to the bypass pipe 114.

Japanese Patent Laid-Open No. 10-63644

  The conventional dust removing device can remove water-soluble substances in the gas and condensable dust such as tar by contact with a water jet water droplet jet, but the water after gas cleaning stored in the circulation tank 105 is removed. The increased amount of the supplied water vapor is discharged after passing through the strainer 109. However, even when the drainage 100 has a drainage regulation value, there is a problem that it has a tar odor and cannot be discharged as it is. .

  Further, the water after gas cleaning may contain cyan recovered from the gas 101, and the amount may slightly exceed the drainage regulation value.

  This invention is made | formed in view of the said conventional situation, It aims at providing the organic substance containing gas processing system which can eliminate the said conventional trouble and can remove the tar odor in waste_water | drain. Is.

  The first invention of the present invention for solving the above-mentioned problems is a dust removing device that removes dust in an organic substance-containing gas by a water jet scrubber, and in a wastewater that dust is removed by a water jet scrubber of the dust removing device. An organic substance-containing gas treatment system comprising: a flotation separation device that removes a fine particle component; and a stripping tower that removes a tar component in waste water from which the fine particle component has been removed by the flotation separation device.

  A second invention is the organic substance-containing gas treatment system according to the first invention, wherein the temperature of the stripping tower is 40 ° C. or higher.

  According to a third aspect of the present invention, there is provided the organic substance-containing gas treatment system according to the first aspect, wherein the pH of the waste water supplied to the stripping tower is 8 or more.

  According to a fourth aspect of the present invention, there is provided the organic substance-containing gas treatment system according to the first aspect of the invention, wherein the stripping tower is a two-column type.

  According to a fifth aspect of the present invention, in the fourth aspect, the pH of the wastewater supplied to the front-side diffusion tower of the series two-column type is 9 to 14, and the pH of the wastewater supplied to the latter-side diffusion tower is 1 to 4 is an organic substance-containing gas processing system.

  A sixth invention is an organic substance-containing gas processing system according to any one of the first to fifth inventions, wherein the organic substance-containing gas is a biomass gasification gas obtained by gasifying biomass.

  Further, as a liquid fuel production system to which the organic substance-containing gas processing system is applied, for example, a gasification fuel is supplied and gasified with an oxidizing agent containing water vapor, and a generated gas generated in the gasification furnace A dust removal device that removes dust from a dust by a water jet scrubber, a gas purification device that purifies the dust-removed gas, a liquid fuel synthesis device that synthesizes liquid fuel using the purified gas, and a water jet of the dust removal device Providing a system characterized by comprising a strainer that removes particulate components in wastewater from which dust has been removed by a scrubber, and a stripping tower that removes tar components in wastewater from which particulate components have been removed by the strainer. it can.

  ADVANTAGE OF THE INVENTION According to this invention, harmful components, such as a tar content, ammonia content, and cyan content, in the waste_water | drain discharged | emitted from the dust removal apparatus which refine | purifies the gas containing organic substance can be removed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A system for processing an organic substance-containing gas according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram illustrating an organic substance-containing gas processing system according to a first embodiment.
As shown in FIG. 1, the organic substance-containing gas processing system according to the present embodiment includes a dust removing device 201 that removes dust in a generated gas 66 that is an organic substance-containing gas by a water jet scrubber 4, and water in the dust removing device 201. Strainer 17 which is a floating separation device that removes fine particles from discharged water 201a from which dust is removed by jet scrubber 4, and tar components in drainage extracted from a part of circulating water 201b from which fine particles are removed by strainer 17. And a stripping tower 211 for removing water. Examples of the organic substance-containing gas include a product gas obtained by gasifying a biological resource or a fossil resource, and particularly a biomass gasification gas obtained by gasifying a biomass resource such as wood.

The temperature of the stripping tower 211 is preferably 40 ° C. or higher, more preferably 80 ° C. or higher. This is because the volatile component moves to the gas phase side by raising the temperature.
Thereby, the tar in the waste water 100 is removed, and as a result, the tar odor is removed.
Moreover, since the waste water from which the volatile components have been removed by the diffusion tower 211 becomes equal to or less than the waste water reference value, the water can be discharged 213.
The diffusion tower 211 may be one having a plurality of known diffusion shelves.

Moreover, it is good to adjust pH of the waste_water | drain 100 supplied to the said stripping tower to 8 or more.
This is because the ammonia component is removed by using the alkali side. The pH is preferably 9 to 14. The removed ammonia can be used, for example, for ammonium sulfate synthesis.

Here, the case where it applies to the liquid fuel manufacturing system to which this invention is applied is demonstrated with reference to FIG. FIG. 2 is a conceptual diagram showing a liquid fuel production system according to this example.
As shown in FIG. 2, the liquid fuel production system according to the present embodiment supplies biomass 60 that is gasified fuel by a biomass supply means 62 and an oxidant 63 containing water vapor that is supplied by an oxidant supply means 64. A gasification furnace 61 for gasifying the supplied biomass 60; a dust removing device 201 for removing dust in the generated gas 66 generated in the gasification furnace 61 by a water jet scrubber 4; and purifying the dust-removed gas Gas refiner 68, a liquid fuel synthesizer 73 for synthesizing, for example, methanol 70, which is a liquid fuel using the refined gas, and fine components in the waste water 100 from which dust is removed by the water jet scrubber of the dust remover And a stripping tower 211 for removing the tar component in the waste water 100 from which the fine particle component has been removed by the strainer 17. It is intended to comprise. In the present embodiment, the liquid fuel synthesizing apparatus 73 includes a methanol synthesizing apparatus 71 that synthesizes methanol using a methanol reforming catalyst or the like, and a gas component in the synthesized methanol. Although comprised from the gas-liquid separation apparatus 74 isolate | separated as the waste gas 69, this invention is not limited to this.

  Here, as the dust removing device 201 using the water jet water droplet jet shown in FIG. 1, for example, the generated gas 66 containing dust such as gas generated in a biomass gasification furnace is sucked to make the water jet water droplet jet 2 vertical. A driving nozzle 3 formed in the axial direction, and the water jet water droplet jet 2 and the dust-containing gas 1 communicated with the driving nozzle 3 and received so as to cover the water jet water droplet jet 2 discharged from the driving nozzle 3. A cylindrical scrubber portion 4 for removing dust from the generated gas 66, and a suction pipe 5 for receiving the water jet water droplet jet 2 flowing down from the water jet scrubber 4 and temporarily storing it as circulating water; A level tank 6 communicating with the suction pipe 5 and storing a certain level of water therein, and disposed in the suction pipe 5, and circulating water in the suction pipe 5 is forced by a circulation pump 7. A discharge pipe 8 for output, is forced discharged water from the suction pipe 5 intended to and a circulation line 9 for circulating the driving nozzle 3. In the present embodiment, the drainage tower 211 is treated as the drainage 100 by extracting a part of the circulating water in the circulation line 9. However, the present invention is not limited to this, for example, directly from the strainer 17. It may be introduced into the stripping tower 211.

By applying the organic substance-containing gas treatment system to this liquid fuel production system, when a part of the circulating water from which the fine particle component is separated by the strainer 17 is discharged, the tar component in the waste water is removed. The odor will disappear and the manufacturing environment will be improved.
Moreover, ammonia, a cyan component, etc. will be removed by adjusting pH of the waste_water | drain 100 supplied to the said stripping tower to 8 or more.

  Here, the removed volatile components (ammonia, cyan, tar, etc.) 212 may be thermally decomposed in the gasification furnace 61, for example.

FIG. 3 is a conceptual diagram illustrating a liquid fuel production system to which the organic substance-containing gas processing system according to the second embodiment is applied.
As shown in FIG. 3, the liquid fuel production system according to the present embodiment is the same as the system of the first embodiment. A first stripping tower 211-1 to be treated, and a second stripping tower 211-2 to be treated by adding sulfuric acid to the waste water after leaving the first stripping tower 211-1, so as to be acidified. Is.
This is because the stripping tower may be of a single tower type as in Example 1, but more efficient processing can be performed by using a tower with different processing conditions in a series of two towers.

In this two-column type, the pH of the wastewater supplied to the first diffusion tower 211-1 on the front stage side is adjusted to 9 to 14, and the pH of the wastewater supplied to the second diffusion tower 211-2 on the rear stage side is adjusted. By adjusting to 1 to 4, ammonia can be removed on the front side and cyan can be removed on the rear side.
At this time, the tar odor is further reduced by the treatment of the two-stage stripping tower.

  According to the present invention, when the tar content generated when the biomass which is gasified fuel is converted into steam gas is removed by the water scrubber, the tar odor is transferred to the water side. By using a two-column diffusion tower, tar odor can be further reduced.

FIG. 4 is a conceptual diagram illustrating a liquid fuel manufacturing system to which an organic substance-containing gas processing system according to a third embodiment is applied.
As shown in FIG. 4, the liquid fuel production system according to the present embodiment is a system in which a coagulation sedimentation tank 214 is installed on the upstream side of the stripping tower 211 in the system of the first embodiment.
By collecting the suspended particles contained in the waste water 100 by the coagulation sedimentation tank 214, the COD value can be reduced. In addition to the recovery of the suspended particles, the tar component is also removed along with the suspended particles, so that the tar odor can be reduced. In addition, suspended substances can be separately collected and used as fuel.

[Test example]
Hereinafter, although the test example which shows the effect of this invention is demonstrated, this invention is not limited to this.

Using an apparatus having a two-column type diffusion tower shown in FIG. 2, a test simulating the recovery of particles in the gas from the biomass gasification furnace was conducted 10 times.
The conditions of this test and the results of the test are summarized in “Table 1” and “Table 2” below.

As shown in “Table 1”, in the first tower stripping tower 211-1, the temperature is 80 ° C., the pH is 10, the amount of drainage / gas flow (L / G) is 13 L / m ^3, and the stripping tower of the second tower In 211-2, the test was performed at a temperature of 80 ° C., a pH of 3, a residence time of 30 minutes, and a drainage / gas flow rate (L / G) of 13 L / m ³ .

As shown in “Table 2” showing the test results, the COD before the treatment was 80 to 200 mg O / L, whereas it was reduced to 15 to 40 mg O / L after the treatment. In addition, the oil content was 1-2 mg O / L, but after the treatment, the oil content was reduced to 1 mg O / L or less.
Also, the total nitrogen was reduced to 55 to 70 mg O / L after the treatment, compared to 200 to 700 mg O / L before the treatment. In addition, ammonia was 180 to 650 mgO / L, but was reduced to 40 to 55 mgO / L or less. Further, cyan was 2 to 10 mg O / L, while it was reduced to 0.01 to 0.15 mg O / L or less.
Moreover, tar odor was also reduced. The COD and oil content derived from the tar content are also reduced and below the regulation value, which supports the reduction of the tar odor.

  As described above, the organic substance-containing gas processing system according to the present invention efficiently removes the tar content that has moved to the water phase side when dust is removed from the product gas obtained by steaming gasification fuel such as biomass. And is suitable for use in a system for producing steam gasified fuel.

It is the schematic of the organic substance containing gas processing system concerning Example 1. FIG. 1 is a schematic diagram of a liquid fuel production system to which an organic substance-containing gas treatment system according to Example 1 is applied. It is the schematic of the liquid fuel manufacturing system to which the organic substance containing gas processing system concerning Example 2 is applied. It is the schematic of the liquid fuel manufacturing system to which the organic substance containing gas processing system concerning Example 3 is applied. It is the schematic of the conventional liquid fuel manufacturing system. It is the schematic of the apparatus using a water jet water droplet jet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Waste water 211 Stripping tower 211-1 1st stripping tower 211-2 2nd stripping tower 212 Volatile component 213 Water discharge 104 Coagulation sedimentation tank 60 Biomass 61 Gasification furnace 4 Water jet scrubber

Claims (6)

A dust removing device for removing dust in the organic substance-containing gas with a water jet scrubber;
A flotation separator that removes particulate components in the wastewater from which dust has been removed by the water jet scrubber of the dust remover;
An organic substance-containing gas treatment system comprising: a stripping tower for removing a tar component in waste water from which a fine particle component has been removed by the floating separation device. In claim 1,
An organic substance-containing gas treatment system, wherein the temperature of the stripping tower is 40 ° C or higher. In claim 1,
The organic substance-containing gas treatment system, wherein the pH of the wastewater supplied to the stripping tower is 8 or more. In claim 1,
2. The organic substance-containing gas treatment system, wherein the stripping tower is a two-column type. In claim 4,
The organic substance-containing gas treatment characterized in that the pH of the wastewater supplied to the first-stage diffusion tower of the series two-column type is 9 to 14, and the pH of the wastewater supplied to the latter-side diffusion tower is 1 to 4. system. In any one of Claims 1 thru | or 5,
The organic substance-containing gas processing system, wherein the organic substance-containing gas is a biomass gasification gas obtained by gasifying biomass.

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