JP4728984B2 - Gasification gas purification method and purification device - Google Patents

Description

  The present invention relates to a purification method and purification device for gasification gas obtained by pyrolyzing organic waste such as waste plastic and biomass or solid organic matter such as coal, and in particular, the purification of gasification gas using an activated carbon packed tower. The present invention relates to a purification method and a purification device.

  In recent years, effective use of energy has been attracting attention as part of global environmental conservation, especially prevention of global warming. Organic waste is a method for effectively using energy of organic waste such as waste plastic and biomass. So-called gasification, which obtains a combustible gas by pyrolyzing the gas, is attracting attention.

  However, combustible gas obtained by gasification, that is, gasification gas contains dioxin due to chlorine contained in organic waste, so it is necessary to remove dioxin when using gasification gas It is. In addition to dioxins, organic waste gasification gases include high-boiling hydrocarbon compounds that are liquid or solid at normal temperature and pressure, such as tar and light oil (in the present specification, simply “high-boiling hydrocarbon compounds”). Here, the boiling point of the “high-boiling hydrocarbon compound” is approximately 60 ° C. or higher). These high boiling hydrocarbon compounds have a high vapor pressure even at temperatures below the boiling point and are difficult to remove by cooling, etc., and the high boiling hydrocarbon compounds remaining in the gas condense when the temperature of the gasification gas decreases. In addition, it may cause equipment trouble by adhering to the gas piping and its ancillary equipment. Therefore, it is necessary to remove from gasification gas with dioxin.

  Conventionally, as a technique for removing dioxins in a gas, Patent Document 1 discloses a technique in which dioxins are decomposed by a catalyst layer and the remaining dioxins are adsorbed by an activated carbon layer. However, the technique of this patent document 1 is mainly intended for treating the combustion exhaust gas after burning a combustible substance, and when the technique of patent document 1 is applied to the treatment of gasification gas of organic waste. In the catalyst layer, hydrocarbon gases other than dioxins are also decomposed and soot is generated. Moreover, in the activated carbon layer, the above-described high boiling point hydrocarbon compound is adsorbed in addition to dioxin, and the activity of the activated carbon cannot be maintained. In order to sustain it, it is necessary to always use new activated carbon, which increases operating costs.

  In Patent Document 2, a dust collector such as a bag filter is provided, and powdered activated carbon is blown upstream thereof to form an activated carbon layer on the filter cloth surface of the bag filter, and dioxins are adsorbed on the activated carbon. This technique is disclosed. However, even in the technique of this Patent Document 2, when this is applied to the treatment of gasification gas of organic waste, troubles such as clogging occur due to the above-mentioned high boiling point hydrocarbon compound contained in the gasification gas, Stable operation cannot be continued.

  On the other hand, Patent Document 3 and Patent Document 4 disclose a purification technique using activated carbon to remove hydrocarbons such as solvents and light oil in exhaust gas. However, when the light oil contained in the gasification gas of organic waste is removed by activated carbon, it is difficult to control gas purification because the raw material of the gas is waste and the properties of the raw material are not stable. Since the gasified gas contains not only light oil but also tar, if the gas containing tar is purified by activated carbon, the tar is not easily separated from the activated carbon, and the life of the activated carbon is shortened.

  Patent Documents 5 and 6 disclose a technique for purifying biomass gas (gasification gas) obtained by pyrolyzing biomass using activated carbon. However, with this technology, it is possible to adsorb and remove tar components having a high gas treatment temperature and a high molecular weight and a high boiling point, but they have a low molecular weight, a relatively low boiling point, a high volatility, and a normal temperature. It is impossible to adsorb and remove liquid hydrocarbon compounds, so-called light oil components, under pressure. Light oil is cooled in the piping and drained when using gas. Since this drain is a highly volatile flammable oil, it is difficult to handle. In addition, in the case of gasification gas using raw materials other than biomass with uniform properties, the generation amount and properties of tar may change, the activated carbon adsorption layer may be clogged, and light oil may flow to the gas utilization facility, causing problems. There is sex. In particular, when fossil fuels such as waste plastics and coal, or solid organic substances made from fossil fuels are gasified, the amount of tar and light oil is large, and the above-mentioned technique cannot perform sufficient purification. .

  As described above, various techniques for purifying gas using activated carbon have been proposed in the past. However, when purifying gasification gas containing a high boiling point hydrocarbon compound, particularly tar and light oil, the above-mentioned problems are required. However, gasification gas purification technology using activated carbon has not been established.

  On the other hand, a gasification gas purification technique that does not use activated carbon has also been proposed. For example, Patent Document 7 discloses a technology for reducing tar content and light oil content in gasified gas by gasification of organic waste, reaction with oxygen and water vapor, and reforming reaction at a high temperature of about 1100 ° C. Proposed. However, gas purification technology using such a reforming reaction requires partial combustion of the gasified gas in order to obtain a heat source required for the reforming reaction. There is a problem of lowering. In addition, the production of oxygen used for the reforming reaction requires a lot of energy, and the total energy required for waste treatment becomes too large.

  As another gas cleaning technology, as seen in coke oven gas purification technology, there is a technology in which gas is cleaned with oil at a low temperature to remove tar content and light oil content in the gas. However, with this technique, energy is required to obtain a cold heat source for cleaning at low temperatures. Moreover, advanced treatment is required for the waste water after washing, and further, a step of regenerating oil and the like is required, and facilities such as treatment of gas generated at the time of regeneration tend to be complicated. Further, dioxins cannot be removed by gas cleaning.

  Thus, in order to purify the gas by simultaneously removing high-boiling hydrocarbon compounds such as dioxin, tar, and light oil in the gas, it is useful and simple to dry-process using activated carbon. Establishing gasification gas purification technology using methane is desired.

On the other hand, when an organic substance is thermally decomposed to obtain a combustible gasification gas, it is desirable to keep hydrocarbon gas such as methane and keep gas calorie high when using the gasification gas. In this case, however, tar and light oil are by-produced and hinder gas utilization. Therefore, establishment of the purification technology which removes the tar content and light oil content in gasification gas also from this point is desired.
Japanese Patent Laid-Open No. 2003-112012 JP-A-11-230529 JP-A-9-215908 JP 2005-66503 A JP 2006-16469 A JP 2006-16470 A JP 2004-238535 A

  The problem to be solved by the present invention is to establish a purification technology for gasification gas using activated carbon and obtain a usable high calorie gas.

  Specifically, even if the adsorption capacity of the activated carbon is reduced due to the adsorption of the high-boiling hydrocarbon compound in the gasification gas, the adsorption capacity can be efficiently recovered and the gas purification capacity of the apparatus can be maintained. An object of the present invention is to provide a purification method and a purification device for gasification gas.

In the present invention, gasification gas obtained by pyrolyzing organic waste or solid organic matter such as coal is passed through an activated carbon type adsorption device comprising a plurality of activated carbon adsorption towers, and activated carbon is subjected to high boiling point carbonization in the gasification gas. In the gasification gas purification method for adsorbing a hydrogen compound, the activated carbon adsorption tower whose adsorption capacity is reduced by adsorption of the high boiling point hydrocarbon compound is blocked by passing the gasification gas and adsorbed by passing steam. The high boiling point hydrocarbon compound is released and discharged to the vapor side as waste vapor to recover the adsorption capacity. After that, the gasification gas is restarted, and the high boiling point hydrocarbon compound discharged from the activated carbon adsorption tower is included. Waste steam or waste drain condensed with waste steam is blown into a gasification furnace that thermally decomposes organic waste or solid organic matter such as coal into gasification, or a combustion furnace that supplies heat to the gasification furnace. Characterized in that the write heat source.

  In the present invention, waste plastic is typically gasified as organic waste, or coal is gasified as solid organic matter.

  The organic waste or solid organic gasification gas contains dioxin and a high-boiling hydrocarbon compound. High boiling point hydrocarbon compounds include tar components such as naphthalene and anthracene (polymer hydrocarbon compounds having 10 or more carbon atoms) and light oil components such as benzene, toluene and xylene (low carbon number of less than 10). Molecular hydrocarbon compounds). These dioxins and high-boiling hydrocarbon compounds need to be removed for effective use of gasification gas. In the present invention, as described above, the activated carbon-type adsorption device composed of a plurality of activated carbon adsorption towers is used for organic disposal. Dioxins and high-boiling hydrocarbon compounds contained together with combustible gas in the gasification gas of the product or solid organic matter are removed.

  That is, the activated carbon packed in the activated carbon adsorption tower has innumerable pores on the surface, and dioxin and polymer hydrocarbon compound molecules enter the pores to be adsorbed and removed from the gasification gas. .

  And among the plurality of activated carbon adsorption towers constituting the activated carbon adsorption apparatus, for the activated carbon adsorption tower whose adsorption capacity is reduced by adsorption of the high boiling point hydrocarbon compound, the gasification gas passage is shut off and the vapor is allowed to pass. The high boiling point hydrocarbon compound adsorbed on the pores of the activated carbon can be vaporized and released, the pores of the activated carbon can be restored, and the adsorption ability can be restored.

  Thereafter, the gasification gas passing through the activated carbon adsorption tower whose adsorption capacity has been restored is restarted. By repeating this operation, the gas purification capacity of the apparatus can be maintained.

In order to carry out this gasification gas purification method, in the purification apparatus of the present invention, a plurality of dioxins and high-boiling hydrocarbon compounds in the gasification gas obtained by pyrolyzing organic waste or solid organic matter are adsorbed. In the gasification gas purification apparatus having an activated carbon type adsorption device that is an activated carbon adsorption tower, an open / close valve is provided on the gas introduction side and the discharge side of each activated carbon adsorption tower, and the activated carbon is regenerated in each activated carbon adsorption tower. The waste steam containing the high boiling point hydrocarbon compound discharged from the activated carbon adsorption tower or the waste drain condensed with the waste steam is converted into organic waste or solid organic matter such as coal. A pipe for returning to a gasification furnace for pyrolyzing the gas to a gasification furnace or a combustion furnace for supplying heat to the gasification furnace is provided .

  That is, for activated carbon adsorption towers that have reduced adsorption capacity due to adsorption of high-boiling hydrocarbon compounds, the on-off valves provided on the gas introduction side and the discharge side are closed to shut off the gasification gas and allow the vapor to pass. To restore the adsorption capacity. Thereafter, the on-off valve is opened to restart the gasification gas flow.

Further, in the present invention, a gasification furnace that gasifies waste waste containing high boiling point hydrocarbon compounds discharged from an activated carbon adsorption tower or waste drain condensed with waste steam, by thermally decomposing organic waste or solid organic matter. Alternatively, the heat source is blown into a combustion furnace that supplies heat to the gasification furnace . The recovered waste steam or drainage often contains high-boiling hydrocarbon compounds and organic chlorine compounds such as dioxins. In particular, organic chlorine compounds are often highly toxic and difficult to handle. is there. Therefore, as described above, the recovered waste steam or waste drain is blown into an adjacent gasification furnace or combustion furnace, so that it can be incinerated and made harmless and dissipated.

  That is, according to this method, waste steam or waste drain generated in the recovery process of the activated carbon adsorption tower can be efficiently rendered harmless without newly providing a harmless treatment device such as a waste water treatment device.

  As a method of blowing into the gasification furnace or combustion furnace, a method of blowing the waste steam as it is, a method of draining the waste steam into waste drain, separating it into water and oil using an oil-water separator, and blowing the oil are adopted. be able to. In the case of waste draining, the oil and the separated water can be discharged out of the system after incineration or waste water treatment. As a method of waste draining, a method of cooling by providing a condenser or the like at the exhaust port of the waste steam can be employed.

  Further, in the present invention, before passing the gasification gas through the activated carbon-type adsorption device, mist-like moisture contained in the gasification gas, tar content in the high-boiling hydrocarbon compound, and solid dust are removed, and then The gasification gas can be passed through an activated carbon adsorption device. The gasification gas of organic waste or solid organic matter contains tar as well as light oil as a high-boiling hydrocarbon compound. The tar content is a relatively high molecular weight hydrocarbon compound of high boiling point, and when adsorbed on activated carbon, it becomes difficult to detach and may significantly shorten the life of the activated carbon. For this reason, in this invention, it is preferable to remove a tar content before letting gasification gas pass an activated carbon type adsorption apparatus.

The tar content of the gasification gas on the inlet side of the activated carbon adsorption device is preferably 1 g / Nm ³ or less. Thus, by removing the tar content in advance, the activated carbon can be protected and its activity can be maintained for a long time. It is also preferable to remove mist-like moisture and solid dust together with the tar content.

  When the relative humidity of the gasification gas passing through the activated carbon adsorption tower is close to 100%, the activated carbon in the activated carbon adsorption tower adsorbs the mist-like water contained in the gasification gas and cannot obtain the required activity. . Therefore, it is preferable to remove the mist-like water and solid dust together with the tar content in advance. As means for removing tar content, mist-like moisture, and solid dust, a dust collector such as an electric dust collector or a cyclone can be provided upstream of the activated carbon adsorption device.

  Further, in the present invention, the gas temperature is cooled to 60 ° C. or lower before the gasified gas is passed through the activated carbon-type adsorption device, and the mist-like moisture contained in the gasified gas after cooling, The tar content and solid soot can be removed, and then the gasification gas can be heated and passed through an activated carbon adsorption device.

  Thus, by cooling the gas temperature of the gasification gas to 60 ° C. or less, preferably 40 ° C. or less, the mist formation of the tar content and moisture in the gasification gas is promoted, and the gasification gas is introduced into the activated carbon adsorption device. Tar, moisture and solid soot can be reliably removed before passing.

  And after removing the tar content, moisture and solid dust, heating the gasification gas, and then passing through the activated carbon adsorption device, it is possible to suppress the draining of the gasification gas in the activated carbon adsorption device, The activity of the activated carbon can be maintained for a long time.

  The temperature of the gasification gas before removing the tar content, moisture and solid dust is better when the tar content and moisture are misted. However, at 20 ° C. or less, the running cost is large for the effect of mist formation. Therefore, it is not preferable.

  The temperature of the gasification gas after removing tar, moisture and solid dust is controlled so that the relative humidity is 60% or less. Thus, in order to cool the gasified gas before passing it through the activated carbon type adsorption device, to remove tar, moisture and solid dust, and then to heat it, the purification device of the present invention uses the activated carbon type adsorption device. A gas cooling device, a dust collector, and a gas heating device can be provided in this order on the upstream side.

  Moreover, in this invention, the temperature of the vapor | steam passed through an activated carbon adsorption tower can be made into the range of 80-300 degreeC. When the temperature of the vapor passing through the activated carbon adsorption tower is a low temperature of about 80 to 150 ° C., among the high boiling point hydrocarbon compounds adsorbed on the activated carbon in the activated carbon adsorption tower, benzene, toluene, having a low molecular weight and a relatively low boiling point, Light oil such as xylene can be removed. When the steam temperature is 80 to 150 ° C., it is difficult to remove tar components such as naphthalene and anthracene having a molecular weight of 100 or more and a high boiling point.

  Therefore, by using steam at a temperature equal to or higher than the boiling point of the tar content, specifically, steam in the range of 80 to 300 ° C., the tar content can be separated from the activated carbon, and the adsorption ability of the activated carbon is reliably recovered. be able to.

  Further, in the present invention, the activated carbon type adsorption apparatus comprising two or more activated carbon adsorption towers is installed in two stages in series in the gasification gas flow direction, and the adsorption capacity of the activated carbon adsorption tower is recovered in the first activated carbon type adsorption apparatus. The temperature of the steam that is passed for the purpose can be made higher than the temperature of the steam that is passed to recover the adsorption capacity of the activated carbon adsorption tower in the second stage activated carbon type adsorption apparatus.

  When only one stage of the activated carbon adsorption device is installed, both the light oil component having a small molecular weight and the tar component having a large molecular weight are adsorbed by one activated carbon adsorption tower. Then, in order to completely recover the adsorption capacity of the activated carbon adsorption tower, high-temperature steam is required as described above, and the running cost becomes high.

  The tar content in the gasification gas can be removed in advance as described above, but since it is difficult to completely remove the tar content, the tar content is adsorbed by the activated carbon adsorption tower even though the amount is small. High temperature steam is required to restore the adsorption capacity of the activated carbon adsorption tower. On the other hand, when the activated carbon type adsorption device is installed in two stages in series in the gasification gas flow direction, the first stage activated carbon type adsorption device adsorbs the polymer hydrocarbon compound such as tar and the like. In the activated carbon type adsorption apparatus, the remaining low-molecular hydrocarbon compounds such as light oil are adsorbed.

  Therefore, the temperature of the steam used to recover the adsorption capacity of the activated carbon adsorption tower in the second stage activated carbon adsorption device can be lower than that in the first stage activated carbon adsorption device, and the running cost can be reduced. Can do. Furthermore, if the tar content is removed by a dust collector on the upstream side of the first stage activated carbon type adsorption device, the amount of the tar content adsorbed by the first stage activated carbon type adsorption device is reduced, The frequency of the adsorption capacity recovery operation using high-temperature steam that requires energy for production can be reduced, and the running cost can be further reduced.

  Also, the activated carbon used in the first and second stage activated carbon adsorption devices can be used for polymer adsorption by changing the size of the pores. Can be used.

As the component range of the gasification gas purification treatment in the present invention, for _{example, H 2 = 5~60vol% (dry} ), CO = 5~50vol% (dry), CO 2 = 3~30vol% (dry) CH ₄ = 0.1 to 30 vol% (dry), and the dioxin concentration is 0.1 ng / Nm ³ or more. Examples of other components are H ₂ = 5 to 60 vol% (dry), CO = 5 to 50 vol% (dry), CO ₂ = 3 to 30 vol% (dry), CH ₄ = 0.1 to 30 vol% (dry) And the total concentration of benzene, toluene and xylene is 1 g / Nm ³ (dry) or more and 50 g / Nm ³ (dry) or less.

In these component examples, the concentration of tar, which is a high-boiling hydrocarbon compound having 7 or more carbon atoms, is 10 mg / Nm ³ (dry) or more. In these component examples, the saturation temperature of water contained in the gas is 20 ° C. or higher and 100 ° C. or lower.

  According to the present invention, even if the adsorption capacity of one of the plurality of activated carbon adsorption towers is reduced due to the adsorption of the high-boiling hydrocarbon compound in the gasification gas, by passing steam through the activated carbon adsorption tower having the reduced adsorption capacity. Since the adsorption capacity is efficiently recovered, the gas purification capacity of the apparatus can be maintained.

  Moreover, since the tar content and light oil content in the gasification gas can be stably removed, an operation with the gasification temperature and the reforming temperature lowered can be performed, and a high calorie gasification gas can be stably obtained. In addition, it is possible to reduce the energy, oxygen amount, and the like necessary for increasing the gas temperature, and it is possible to obtain a high calorie gasified gas at a lower cost.

  Furthermore, the recovered tar content and light oil content can be used as a heat source for thermal decomposition, and the thermal efficiency of the system can be increased.

Embodiments of the present invention will be described below based on examples and reference examples shown in the drawings.

FIG. 1 is an apparatus configuration diagram showing a first reference example of the present invention.

  In FIG. 1, the activated carbon adsorption device 1 includes three activated carbon adsorption towers 1 a to 1 c. The gasification gas obtained in the gasification furnace 2 for gasifying organic waste passes through the gasification gas supply main 3, and then gasification gas supply branches 3a to 3c leading to the activated carbon adsorption towers 1a to 1c, respectively. And is introduced into the activated carbon adsorption towers 1a to 1c from below.

  When the gasification gas is introduced into the activated carbon adsorption towers 1a to 1c, dioxins and high-boiling hydrocarbon compounds in the gasification gas are adsorbed on the activated carbon in the activated carbon adsorption towers 1a to 1c, and then the gasification gas is activated carbon. The gas is discharged from the gasification gas discharge branch pipes 4 a to 4 c connected to the upper portions of the adsorption towers 1 a to 1 c, joins the gasification gas discharge main pipe 4, and is conveyed to the gas utilization facility 5. Specific uses of gasified gas include fuel for industrial furnaces such as heating furnaces and coke ovens, fuel for gas engines and gas turbines, boiler fuel, fuel for hot stove furnaces, and the like.

  The gasification gas supply branch pipes 3a to 3c and the gasification gas discharge branch pipes 4a to 4c are provided with on-off valves 3d to 3f and on-off valves 4d to 4f, respectively. Further, each of the activated carbon adsorption towers 1a to 1c is connected to steam supply branch pipes 6a to 6c branched from the steam supply main pipe 6 at the upper part and to waste steam discharge branch pipes 7a to 7c at the lower part. The steam supply branch pipes 6a to 6c and the waste steam discharge branch pipes 7a to 7c are provided with on-off valves 6d to 6f and on-off valves 7d to 7f, respectively.

  In addition, as the gasification furnace 2, various furnaces, such as a shaft furnace, a rotary kiln furnace, a fluidized bed furnace, a fixed bed furnace, a jet-flow furnace, can be used. Further, the heating method of the gasification furnace 2 may be either a partial combustion method in which the generated gasified gas is partially burned to be a heat source, or an external heat method using an external heat source.

  In the above configuration, during operation, among the three activated carbon adsorption towers 1a to 1c, gasification gas is passed through two towers to purify the gasification gas, and gasification gas is passed through the remaining one tower. Without passing the vapor, the adsorbed high boiling point hydrocarbon compound is released and discharged to the vapor side as waste vapor to recover the adsorption capacity.

  For example, when passing the gasification gas to the activated carbon adsorption towers 1a and 1b, the on-off valves 3d and 3e of the gasification gas supply branch pipes 3a and 3b for supplying the gasification gas to the activated carbon adsorption towers 1a and 1b are opened. At the same time, the on-off valves 4d and 4e of the gasification gas discharge branches 4a and 4b for discharging the gasification gas from the activated carbon adsorption towers 1a and 1b are opened. And on-off valves 6d, 6e of steam supply branch pipes 6a, 6b for introducing steam into activated carbon adsorption towers 1a, 1b and on-off valves 7d of waste steam discharge branch pipes 7a, 7b for discharging waste steam from activated carbon adsorption towers 1a, 1b, 7e is closed. As a result, the gasification gas is passed through the activated carbon adsorption towers 1a and 1b, and the dioxins and high-boiling hydrocarbon compounds in the gasification gas are adsorbed and removed.

  For the remaining activated carbon adsorption tower 1c, the on-off valve 3f of the gasification gas supply branch 3c and the on-off valve 4f of the gasification gas discharge branch 4c are closed, and the on-off valve 6f of the steam supply branch 6c and waste steam discharge are closed. The on-off valve 7f of the branch pipe 7c is opened.

  As a result, the gasification gas passing through the activated carbon adsorption tower 1c is blocked and steam is passed instead. The high boiling point hydrocarbon compound adsorbed on the activated carbon adsorption tower 1 is released by this vapor and discharged to the vapor side as waste vapor, so that the adsorption capacity of the activated carbon adsorption tower 1 is restored. The waste steam is discharged from the lower part of the activated carbon adsorption tower 1 through the waste steam discharge branch pipe 7c, and after joining the steam discharge main pipe 7, is transported to a predetermined place.

  Thereafter, when the adsorption capacity of any one of the activated carbon adsorption towers 1a and 1b in the gasification gas is reduced or when a predetermined time has elapsed from the gasification gas passage, the operation of the on-off valve as described above is performed. Then, the gasification gas flow to any one of the activated carbon adsorption towers having reduced adsorption capacity is shut off. Instead, the gasification gas is passed through the activated carbon adsorption tower 1c whose adsorption capacity has been recovered.

Thus, in this reference example , among the three activated carbon adsorption towers 1a to 1c, gasification gas is passed through two towers, and the remaining one tower is subjected to an operation for recovering the adsorption capacity to recover the adsorption capacity. By sequentially switching the activated carbon adsorption tower that performs the operation, the purification process of the gasification gas can be performed continuously while maintaining the adsorption capacity.

  In addition, as operation conditions, it is preferable that the gas temperature of the gasification gas introduce | transduced into activated carbon adsorption tower 1a-1c shall be 100 degrees C or less. If the gas temperature exceeds 100 ° C., the vapor pressure of the high-boiling hydrocarbon compound in the gasification gas becomes high, the volatility becomes higher than the adsorption power by the activated carbon, and sufficient adsorption capacity cannot be secured. The gas temperature is preferably 60 ° C. or lower. However, if the gas temperature is set to 40 ° C. or lower, for example, the temperature of the cooling water necessary for cooling the gasification gas cannot be obtained by general equipment such as a cooling tower, and a refrigerator is required. Use of a refrigerator is not preferable because it imposes a heavy burden on equipment costs and running costs. Moreover, the temperature of the vapor | steam introduce | transduced for the adsorption capacity recovery | restoration of an activated carbon adsorption tower shall be 80-300 degreeC.

FIG. 2 is an apparatus configuration diagram showing a first embodiment of the present invention. In this embodiment, the activated carbon adsorption device 1 includes two activated carbon adsorption towers 1a and 1b. At the start of operation, gasification gas is passed through both activated carbon adsorption towers 1a and 1b, and after that, if the adsorption capacity of any activated carbon adsorption tower decreases, or if a predetermined time elapses from the gasification gas passage. Then, the gasification gas flow to any one of the activated carbon adsorption towers having reduced adsorption capacity is shut off.

  For example, when shutting off gas flow to the activated carbon adsorption tower 1a, the on-off valve 3d of the gasification gas supply branch 3a and the on-off valve 4d of the gasification gas discharge branch 4a are closed. Then, the on-off valve 6d of the steam supply branch 6a and the on-off valve 7d of the waste steam discharge branch 7a are opened, and steam is passed through the activated carbon adsorption tower 1 to restore the adsorption capacity. When the adsorption capacity is restored, the on-off valve 6d of the steam supply branch 6a and the on-off valve 7d of the waste steam discharge branch 7a are closed, and the on-off valve 3d of the gasification gas supply branch 3a and the on-off valve of the gasification gas discharge branch 4a 4d is opened and gasification gas passage is resumed.

  After that, when the adsorption capacity of the other activated carbon adsorption tower 1b is reduced, the gasification gas is shut off and then the adsorption capacity is recovered through steam, as in the case of the activated carbon adsorption tower 1a. Restart the gas flow. In this embodiment, by repeating such an operation, it is possible to continuously purify the gasification gas while maintaining the adsorption capacity.

  Further, in this embodiment, the combustion for supplying heat to the gasification furnace 2 through the waste steam discharge main 7 from the waste steam discharged when the adsorption capacity of the activated carbon adsorption tower is recovered or the waste drain condensed. Blow into furnace 2a. As a result, the high boiling point hydrocarbon compound contained in the waste steam or waste drain can be effectively used as part of the fuel in the combustion furnace 2a, and the harmful substances such as the organic chlorine compound contained in the waste steam or waste drain are incinerated. It can be detoxified and released.

FIG. 3 is an apparatus configuration diagram showing a second embodiment of the present invention. This embodiment is a modification of the first embodiment described above, and waste steam discharged when the adsorption capacity of the activated carbon adsorption tower is recovered or waste drain condensed with the waste steam is directly blown into the gasification furnace 2 for partial combustion. It is what I did.

FIG. 4 is an apparatus configuration diagram showing a third embodiment of the present invention. In this embodiment, in the apparatus configuration of the first embodiment shown in FIG. 2, on the upstream side of the activated carbon type adsorption apparatus 1, the mist-like moisture contained in the gasification gas, the tar content of the high-boiling hydrocarbons, In addition, an electrostatic precipitator 8 is provided as a dust collector for removing solid dust.

  The electric dust collector 8 may be either a dry type or a wet type, and the dust collector may be a cyclone, a filtration type or a scrubber type in addition to the electric dust collector 8.

  In this way, the electrostatic precipitator 8 is provided upstream of the activated carbon type adsorption device 1 to remove the tar, moisture and solid dust beforehand, thereby protecting the activated carbon of the activated carbon adsorption tower and maintaining its activity for a long period of time. can do. As shown in FIG. 4, gas treatment such as gas scrubbing with a water scrubber or an oil scrubber may be performed as a pretreatment on the upstream side of the electric dust collector 8.

FIG. 5 is an apparatus configuration diagram showing a fourth embodiment of the present invention. This embodiment is the apparatus configuration of the third embodiment shown in FIG. 4, the gas cooling device for cooling the gasification gas in the upstream side of the electrostatic precipitator 8 is provided with the (cooling tower) 9, under flow of an electric precipitator 8 A gas heating device 10 for heating the gasification gas is provided on the side.

  Thus, by providing the gas cooling device 9 upstream of the electrostatic precipitator 8 and cooling the gas temperature of the gasification gas to 60 ° C. or less, preferably 40 ° C. or less, the content of tar or moisture in the gasification gas is reduced. Mistization is promoted, and tar, moisture, and solid dust can be reliably removed by the electric precipitator 8 before passing the gasification gas through the activated carbon adsorption device 1. Then, after removing the tar content, moisture and solid dust, the gasified gas is heated by the gas heating device 10 and then passed through the activated carbon type adsorption device 1, thereby draining the gasification gas in the activated carbon type adsorption device 1. The activation of activated carbon can be maintained for a long time.

FIG. 6 is an apparatus configuration diagram showing a second reference example of the present invention. In this reference example , an activated carbon type adsorption device comprising two activated carbon adsorption towers is provided in two stages in series in the gasification gas flow direction.

  Thus, when two stages of activated carbon type adsorption apparatuses are provided in series, the first stage activated carbon type adsorption apparatus 1 adsorbs the polymer hydrocarbon compound such as tar, and the second stage activated carbon type adsorption apparatus 11 Low molecular hydrocarbon compounds such as light oil are adsorbed. Therefore, the temperature of the steam used for the recovery of the adsorption capacity of the activated carbon adsorption tower in the second stage activated carbon type adsorption apparatus 11 can be made lower than that in the first stage activated carbon type adsorption apparatus 1, and the running cost can be reduced. Can be suppressed.

  Furthermore, if the tar content is removed with an electrostatic precipitator or the like as described in the previous fourth and fifth embodiments on the upstream side of the first-stage activated carbon adsorption device 1, one-stage The amount of tar content adsorbed by the activated carbon type adsorption device 1 is reduced, the frequency of the adsorption capacity recovery operation using high-temperature steam is reduced, and the running cost can be further suppressed. In this embodiment, as the activated carbon used in the first and second stage activated carbon adsorption devices, the first stage is for polymer adsorption, the second stage is for low molecular weight by changing the size of the pores. The one for adsorption was used.

As described above, in each of the examples and the reference examples , the purification method for gasification gas obtained by pyrolyzing organic waste has been described. However, the purification method for gasification gas according to the present invention pyrolyzes organic waste. In addition to the gasified gas obtained in this manner, the present invention can be applied to a gasified gas obtained by thermally decomposing solid organic matter such as coal, for example, coke oven gas or coal gasified fuel gas.

  Conventionally, in the coke oven gas purification method, light oil is collected using cleaning oil containing naphthalene, etc., the light oil is heated to separate the light oil, and the separated light oil is separated. It was made to collect by cooling and condensing. However, this method complicates the equipment and increases the cost. Moreover, although it is useful when the separated light oil component is used separately, it is necessary to separately process the light oil component when there is no means for using the light oil component alone. Further, since the cleaning oil deteriorates, it is necessary to replace it after a certain period of use, and it is difficult to handle the waste cleaning oil.

On the other hand, in the present invention, the equipment is simple, waste cleaning oil is not generated, and operation management is easy. The present invention is suitable for gas treatment of a medium scale or less with a gas amount of 100,000 Nm ³ / h or less when it is not necessary to recover a light oil component with high purity.

It is an apparatus block diagram which shows the 1st reference example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is an apparatus block diagram which shows 1st Example of this invention. It is an apparatus block diagram which shows 2nd Example of this invention. It is an apparatus block diagram which shows 3rd Example of this invention. It is an apparatus block diagram which shows 4th Example of this invention. It is an apparatus block diagram which shows the 2nd reference example of this invention.

DESCRIPTION OF SYMBOLS 1,11 Activated carbon type adsorption apparatus 1a-1c, 11a, 11b Activated carbon adsorption tower 2 Gasification furnace 2a Combustion furnace 3 Gasification gas supply main 3a-3c Gasification gas supply branch 3d-3e On-off valve 4 Gasification gas discharge main Pipe 4a-4c Gasification gas discharge branch 4d-4e On-off valve 5 Gas utilization equipment 6 Steam supply main 6a-6c Steam supply branch 6d-6e On-off valve 7 Waste steam discharge main 7a-7c Waste steam discharge branch 7d-7e On-off valve 8 Electric dust collector 9 Gas cooling device 10 Gas heating device

Claims (9)

Gasified gas obtained by pyrolyzing organic waste or solid organic matter such as coal is passed through an activated carbon adsorption device consisting of a plurality of activated carbon adsorption towers, and the activated carbon is dioxin in the gasified gas and liquid at normal temperature and pressure Alternatively, in the gasification gas purification method for adsorbing a high-boiling point hydrocarbon compound that is solid, the activated carbon adsorption tower whose adsorption capacity is reduced by adsorption of the high-boiling point hydrocarbon compound is blocked by passing the gasification gas through, The high-boiling point hydrocarbon compound adsorbed by passing through is released and discharged to the vapor side as waste steam to recover the adsorption capacity, and then the gasification gas is restarted and discharged from the activated carbon adsorption tower. A gasifier that gasifies waste steam containing high-boiling hydrocarbon compounds or waste drain condensed with pyrolysis of organic waste or solid organic matter such as coal. Or purification process of gasification gas, characterized by a blowing heat source in the combustion furnace for supplying heat to the gasifier. Before passing the gasification gas through the activated carbon type adsorption device, mist-like moisture contained in the gasification gas, tar content of the high-boiling hydrocarbon compound, and solid dust are removed, and then the gasification gas is removed. The method for purifying a gasification gas according to claim 1, which is passed through an activated carbon type adsorption device . Before passing the gasification gas through the activated carbon type adsorption device, the gas temperature is cooled to 60 ° C. or less, and the mist-like moisture contained in the gasification gas after cooling, the tar content in the liquid hydrocarbon, and the solid dust are removed. The method for purifying a gasification gas according to claim 1, wherein the gasification gas is heated and then passed through an activated carbon adsorption device . The purification method of the gasification gas in any one of Claims 1-3 which makes the temperature of the vapor | steam passed through an activated carbon adsorption tower into the range of 80-300 degreeC . Two stages of activated carbon adsorbers consisting of two or more activated carbon adsorption towers are installed in series in the direction of gasification gas flow, and the first stage activated carbon adsorption apparatus is used to recover the adsorption capacity of activated carbon adsorption tower The purification method of the gasification gas in any one of Claims 1-4 which makes temperature higher than the temperature of the vapor | steam passed in order to recover | restore the adsorption capacity of an activated carbon adsorption tower in the activated carbon type adsorption | suction apparatus of a 2nd stage . Activated carbon comprising a plurality of activated carbon adsorption towers for adsorbing dioxins in gasification gas obtained by pyrolyzing organic waste or solid organic matter such as coal and high-boiling hydrocarbon compounds that are liquid or solid at normal temperature and pressure Supply device for supplying gas for regenerating activated carbon to each activated carbon adsorption tower while providing on / off valves on the gas introduction side and exhaust side of each activated carbon adsorption tower Piping is provided, and waste steam containing the high-boiling hydrocarbon compounds discharged from the activated carbon adsorption tower or waste drain condensed with waste steam is pyrolyzed into organic waste or solid organic matter such as coal and gasified. An apparatus for purifying gasification gas, comprising: a gasification furnace to be used, or a pipe for returning to a combustion furnace for supplying heat to the gasification furnace. The dust collector which removes the mist-like water | moisture content contained in gasification gas, the tar content among the said high boiling point hydrocarbon compounds, and solid soot in the upstream of the activated carbon type adsorption device is provided. Gasification gas purification equipment. A gas cooling device that cools the gasification gas to 60 ° C. or less on the upstream side of the activated carbon adsorption device, mist-like moisture contained in the gasification gas cooled by the cooling device, and the high-boiling hydrocarbon compound The purification apparatus of the gasification gas of Claim 6 which provided the dust collector which removes a tar content and solid soot, and the gas heating apparatus which heats the gasification gas which came out of the dust collector . The purification apparatus of the gasification gas in any one of Claims 6-8 which provided the activated carbon type adsorption apparatus in two steps | paragraphs in series with the flow direction of gasification gas.

Images