JP4636048B2 - Method and apparatus for removing tar from gasification gas - Google Patents

Description

  The present invention relates to a method for removing tar from a gasification gas, which can effectively remove tar generated when a high-quality gasification gas is produced, for example, by gasifying a low-quality raw material with simple equipment. And the apparatus.

  In recent years, techniques for producing high-grade gasification gas by gasifying various low-grade raw materials such as heavy oil, waste oil, petro-coke, biomass, synthetic resin, and rubber have been proposed. Yes.

  FIG. 5 shows an example of a gasification facility for gasifying the raw material. The gasification furnace 1 is maintained at a temperature of, for example, 800 ° C. or higher to gasify the raw material 2 and generate gasified gas 3 generated by gasification. Is introduced into the cyclone 4 to separate the solid content, and then the tar in the gasification gas is removed by various devices at the subsequent stage to purify the gasification gas 3. That is, the gasified gas 3 from which the solid content has been separated by the cyclone 4 is cooled by the double tube cooler 5 and then sprayed with water by the spray tower 6 (scrubber) to remove tar, and then heat exchange. After being cooled by the mold cooler 7, it is supplied to the electrostatic precipitator 9 through the suction fan 8 and water is sprayed (intermittently) to remove tar, and then tar is further removed by the adsorption tower 10 made of activated carbon or the like. The gasified gas 3 that has been refined and purified is supplied to the utilization device 11 as a heating fuel for power generation facilities or as a raw material for a chemical synthesis process.

  The waste water containing a large amount of tar consisting of the mixed water of the spray water and the condensed water from the spray tower 6, the condensed water from the heat exchange type cooler 7, and the spray water from the electric dust collector 9 is a water treatment device. 12 for water treatment such as tar removal.

  However, the apparatus for removing tar from the gasification gas described above has a large number of devices installed, there is a problem that the apparatus is large and complicated, and the amount of wastewater treated by the water treatment apparatus 12 is very large. For this reason, there is a problem that the burden of the processing cost becomes large.

For this reason, as a combustion method in which tar is not generated in the gasification gas, the raw material is combusted in a fluidized bed using a catalyst made of limestone or dolomite, and the generation of tar is prevented by the action of the catalyst. There are some (for example, Patent Document 1).
JP 2005-147517 A

  However, as shown in Patent Document 1, in the method of performing combustion using a catalyst made of limestone or dolomite, it is necessary to continue supplying limestone or dolomite in order to maintain the function of the catalyst. There is a problem that the operating cost due to catalyst consumption increases because it is not so inexpensive. Patent Document 1 is intended for application to a combustion process and is not related to a gasification method.

  In addition, in the gasification method, a method of installing a reforming furnace that decomposes tar by mixing oxygen in the gasification gas and raising the temperature, or installing a high-temperature filter to remove tar from the gasification gas. A method for removing the surface has been proposed, but each method has a problem that the cost is high and it is difficult to actually apply the method.

  The present invention has been made in view of the above-described conventional problems, and a method and apparatus for removing tar from gasification gas that can effectively remove tar generated when gasifying a raw material with simple equipment. The purpose is to provide.

The method for removing tar from gasified gas according to the present invention is to separate the gasified gas produced in the gasification facility by contacting the particles with the particles in the tar adsorption tower so that the tar in the gasified gas adheres to the particles due to temperature drop. A particle supply device for supplying particles to the tar adsorption tower, a particle extraction device for extracting particles in the tar adsorption tower, a temperature detector for detecting the temperature of the gasification gas at the tar adsorption tower outlet, The temperature in the tar adsorption tower is adjusted by an adjustment process using a temperature control device that adjusts the supply of particles by the particle supply device and the extraction of particles by the particle extraction device so that the detection temperature from the temperature detector becomes the set temperature. The amount of particles in the tar adsorption tower is adjusted so as to reach a set temperature.

  In the method for removing tar from the gasification gas, the gasification gas from the gasification facility which is a two-column gasification furnace may be brought into contact with the particles.

  Further, in the above tar removal method from the gasification gas, it is possible to separate tars having different components by bringing the gasification gas separated into contact with particles into contact with another type of particles to separate the tar. It may be.

  In the method for removing tar from the gasification gas, the tar may be supplied to a gasification facility so that the tar is used as a gasification heat source.

  In the method for removing tar from the gasification gas, the particles may be at least one of sand, ash, alumina, and ore.

  In the method for removing tar from the gasification gas, the particles may be ore, and the ore to which tar is attached may be used as a reducing agent in the reduction furnace.

  An apparatus for removing tar from a gasification gas according to the present invention includes a gasification facility, a tar adsorption tower for bringing the gasification gas generated in the gasification facility into contact with particles and attaching the tar to the particles, and the tar adsorption tower A particle supply device for supplying particles to the particle, a particle extraction device for extracting particles in the tar adsorption tower, a temperature detector for detecting the temperature of the gasification gas at the outlet of the tar adsorption tower, and a detection temperature from the temperature detector And a temperature control device for controlling the temperature in the tar adsorption tower by adjusting the supply of particles by the particle supply device and the extraction of particles by the particle extraction device so that the temperature becomes a set temperature.

  In the above tar removal device from gasified gas, the gasification facility separates the fluidized bed combustion furnace, the separator for separating the combustion exhaust gas derived from the fluidized bed combustion furnace into the fluidized medium and the exhaust gas, and the separator. A two-column gasification furnace in which the fluidized medium is supplied together with the raw material, the raw material is gasified by the fluidized bed to extract the gasified gas, and the fluidized medium is supplied to the fluidized bed combustion furnace and circulated may be used.

Moreover, in the tar removal apparatus from the gasification gas, the particles extracted from the tar adsorption tower may be supplied to the fluidized bed combustion furnace.

  Moreover, the tar removal apparatus from the gasified gas may have a plurality of tar adsorption towers for bringing the gasified gas into contact with the particles.

  According to the method and apparatus for removing tar from gasified gas according to the present invention, the gasified gas generated in the gasification facility is brought into contact with the particles so that the tar in the gasified gas adheres to the particles due to the temperature drop and is separated. Since it did in this way, the outstanding effect that the tar in gasification gas can be isolate | separated effectively by simple structure can be show | played.

  By separating the tar with different types of particles by contacting the gasified gas that has been separated from the tar by contacting with the particles, the tars having different components are separated. .

  Since the amount of particles in contact with the gasification gas is adjusted, there is an effect that tar separation can be enhanced by changing the amount of particles in contact with the gasification gas and adjusting the temperature of the gasification gas.

  Since the tar-attached particles are supplied to the combustion furnace to burn the tar, the tar can be used as fuel.

  Since the tar-attached particles are supplied to the gasification facility and the tar is used as a gasification heat source, there is an effect that the heat source for gasification can be reduced.

  The sand used as particles can be the one used or used in the gasification furnace, and the ash used as particles is separated from the exhaust gas, so that the particles can be supplied at low cost. it can. Moreover, when ore is used for the particles, the particles to which tar adheres have an effect of being used as a raw material for a reduction furnace or a blast furnace.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows an example of a gasification facility for carrying out the present invention. This gasification facility 50 is a two-column gasification furnace. The gasification facility 50 includes a fluidized bed combustion furnace 51 that burns char to heat a fluidized medium (sand, etc.) to a temperature of, for example, 800 ° C. or more, and a combustion exhaust gas 52 that is derived from the fluidized bed combustion furnace 51. 53, a separator 55 that separates into an exhaust gas 54, a fluidized medium 53 separated by the separator 55, a raw material 56, and a gasifying agent 57 such as water vapor, air, and carbon dioxide. A fluidized bed gasification furnace 59 in which a fluidized bed 58 is formed. The raw material 56 supplied to the fluidized bed gasification furnace 59 is fluidized and stirred by the fluidized bed 58 of the gasifying agent 57 together with the high temperature fluidized medium 53 to be gasified, and the gasified gas 60 is taken out. On the other hand, the char generated when the raw material is gasified in the fluidized bed gasification furnace 59 is supplied to the lower part of the fluidized bed combustion furnace 51 together with the fluidized medium 53 and circulates, and the char burns in the fluidized bed combustion furnace 51. To heat the fluidized medium 53.

  The gasification gas 60 generated in the fluidized bed gasification furnace 59 is introduced into the tar adsorption tower 61.

  Inside the tar adsorption tower 61, there is provided a screen floor 64 that divides the interior into an upper chamber 62 and a lower chamber 63 and allows gas to flow. A particle supply device 65 that supplies particles to the upper chamber 62. Is provided to form a particle layer 66 having a required thickness on the screen floor 64, and the gasified gas 60 from the fluidized bed gasification furnace 59 is supplied to the upper chamber 62, and the inside of the particle layer 66 is formed. The fixed bed type adsorbing device 73 is configured such that tar is attached to the particles and guided to the lower chamber 63 during the circulation.

  Further, a particle extraction device 67 is provided at a position near the screen floor 64 of the upper chamber 62 so as to extract particles of the particle layer 66 to which tar has adhered.

  A gasified gas 60 circulated in the particle layer 66 is taken out from the lower chamber 63 of the tar adsorption tower 61, and the gasified gas 60 taken out from the tar adsorption tower 61 is used as a fuel for heating power generation equipment or a chemical synthesis process. It is made to supply to the utilization apparatus 68 as a raw material of this. In addition, you may make it provide the minimum tar removal apparatus 69 which consists of an electrostatic precipitator etc. in the upstream of the utilization apparatus 68 as needed.

  The tar adsorption tower 61 is provided with a temperature detector 70 for detecting the outlet temperature of the gasification gas 60. Based on the temperature detected by the temperature detector 70, the supply of particles and the removal of particles by the particle supply device 65 are provided. A temperature control device 71 is provided that controls the temperature in the tar adsorption tower 61 by adjusting the extraction of particles by the extraction device 67.

  As particles to be supplied to the tar adsorption tower 61, sand, ash, alumina, ore and the like can be used. As the sand, sand before being supplied to the gasification facility 50 is used, or a mixture of sand and ash that is accumulated by combustion in the fluidized bed combustion furnace 51 and taken out to the outside is used. Moreover, what was isolate | separated from the waste gas 54 can be utilized for ash.

  Further, in FIG. 1, particles attached with tar extracted from the particle layer 66 of the tar adsorption tower 61 by the particle extraction device 67 are supplied to the fluidized bed combustion furnace 51 using a required supply device as indicated by a supply line 72. I try to burn it. The particles extracted from the particle bed 66 may be supplied to a combustion furnace other than the fluidized bed combustion furnace 51 for combustion, or may be supplied to a reduction furnace or a blast furnace.

  The operation of the above embodiment will be described below.

  The gasified gas 60 from the fluidized bed gasification furnace 59 of the gasification facility 50 is supplied to the upper chamber 62 of the tar adsorption tower 61 and is contained by being cooled while circulating in the particle layer 66. Are removed by adhering to the particles, becoming a clean gasified gas 60 and being guided to the lower chamber 63. At this time, the temperature (particle layer temperature) in the tar adsorption tower 61 can be controlled by adjusting the amount of particles supplied by the particle supply device 65 and the amount of particles extracted by the particle extraction device 67. That is, based on the detected temperature from the temperature detector 70 that detects the temperature of the gasification gas 60 taken out from the lower chamber 63, the temperature control device 71 is set so that the temperature in the tar adsorption tower 61 becomes the set temperature. Controls the supply of particles by the particle supply device 65 and the extraction of particles by the particle extraction device 67.

  FIG. 4 shows the relationship between gasification gas temperature and tar yield when biomass is gasified. Here, the tar yield indicates the tar removal weight per unit weight gasification gas. As shown in FIG. 4, the tar contains a plurality of components that are removed by the condensation temperatures indicated by A, B, and C. When the temperature of the gasification gas is cooled to about 570 ° C. or less, most of the tar components Can be seen to condense.

  Therefore, the temperature control device 71 adjusts the supply of particles by the particle supply device 65 and the extraction of particles by the particle extraction device 67 to control the temperature (particle layer temperature) in the tar adsorption tower 61 to about 570 ° C. or less. Then, the tar in the gasification gas 60 is condensed and adheres to the surface of the particles while passing through the particle layer 66, so that most of the tar in the gasification gas 60 can be removed.

  Thus, since the tar adsorption tower 61 is provided and the tar in the gasification gas 60 is removed, the tar in the gasification gas 60 can be effectively removed with a simple configuration. Further, when it is required to further increase the tar removal rate, a tar removal device 69 including an electric dust collector or the like may be provided upstream of the utilization device 68. In this case, the installation of the tar removing device 69 can be minimized, and therefore, the amount of waste water can be significantly reduced as compared with the conventional case, so that water treatment is facilitated.

  On the other hand, as described above, the particles in the particle layer 66 to which tar is attached are extracted by the particle extracting device 67 and supplied to the fluidized bed combustion furnace 51 by the supply line 72, and used as a gasification heat source by burning the tar. be able to. The particles may be sand before being supplied to the gasification facility 50, or may be a mixture of sand and ash that is deposited by combustion in the fluidized bed combustion furnace 51 and taken out to the outside. Since ash separated from the exhaust gas 54 can be used, these discarded ones can be effectively used as tar removal particles at low cost. Moreover, when alumina is used for the particles, the removal effect of tar can be enhanced because it is porous and has a large surface area. In addition, when ore (iron ore) is used for the particles, the ore with tar attached can be supplied as a raw material to a reduction furnace or blast furnace, and the combustion heat of tar can be used. It can be used as a part of the reducing agent.

  FIG. 2 shows another example of the tar adsorption tower 61. In the configuration in which particles are supplied to the upper chamber 62 by the particle supply device 65 and the particles are extracted from the particle layer 66 by the particle extraction device 67, gasification is performed. The case of the fixed bed type adsorption device 73 in which the gas 60 is supplied from the lower chamber 63 to the particle layer 66 and the gasified gas 60 is taken out from the upper chamber 62 above the particle layer 66 is shown. Here, the fluidized bed type adsorption device 74 can be formed by increasing the flow rate of the gasified gas 60 that is supplied to the lower chamber 63 and moves through the particle layer 66 to form the fluidized bed 66 ′.

  FIG. 3 shows another embodiment of the present invention in which the tar adsorption tower 61 for bringing the gasified gas 60 and particles into contact is configured in multiple stages. In this embodiment, an upper fixed bed type adsorbing device 73a and a lower fixed bed are used. The case where the type | formula adsorption | suction apparatus 73b is provided integrally is shown. The fixed bed type adsorption devices 73a and 73b are provided with particle supply devices 65a and 65b and particle extraction devices 67a and 67b, respectively, and further equipped with temperature control devices 71a and 71b, and are provided in the fixed bed type adsorption devices 73a and 73b. The temperature can be controlled separately. Therefore, based on FIG. 4, when the temperature in the fixed bed type adsorption device 73a is set to 690 ° C. or less and the temperature in the fixed bed type adsorption device 73b is set to 570 ° C. or less, the fixed bed type adsorption device 73a has components. B + C is separated, and the component A can be separated by the fixed bed adsorber 73b.

  In addition, when the fixed bed type adsorption device is provided in three stages and the temperature in each fixed bed type adsorption device is set to 790 ° C. or less, 690 ° C. or less and 570 ° C. or less, component A, component B and component C are separately provided. Can be separated. The tar separated for each component in this way can also be used for a desired purpose of use. In addition, when the tar adsorption tower 61 is configured in multiple stages as described above, a plurality of tar adsorption towers 61 may be separately installed in addition to the method of integrally configuring the tar adsorption tower 61 vertically.

  Note that the present invention is not limited to the above-described embodiment. The present invention is applicable to gasification of various raw materials, various particles can be used as particles supplied to the tar adsorption tower, and other aspects of the present invention. Of course, various changes can be made without departing from the scope of the invention.

It is a schematic side view which shows an example of the gasification installation which implements this invention. It is a schematic side view which shows the other example of a tar adsorption tower. It is a schematic side view which shows the example which provided the tar adsorption tower in multiple stages. It is a diagram which shows the relationship between gasification gas temperature and a tar yield. It is a schematic side view which shows an example of the conventional gasification installation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 Gasification equipment 51 Fluidized bed combustion furnace 52 Combustion exhaust gas 53 Fluid medium 54 Exhaust gas 55 Separator 56 Raw material 58 Fluidized bed 59 Fluidized bed gasification furnace 60 Gasification gas 61 Tar adsorption tower 65 Particle supply apparatus 65a, 65b Particle supply apparatus 66 Particle bed 66 'Fluidized bed 67 Particle extraction device 67a, 67b Particle extraction device 70 Temperature detector 71 Temperature control device 71a, 71b Temperature control device 73 Fixed bed type adsorption device 73a, 73b Fixed bed type adsorption device 74 Fluidized bed type Adsorption device

Claims (10)

Particles that supply particles to the tar adsorption tower when the gasified gas generated in the gasification facility is brought into contact with the particles in the tar adsorption tower and the tar in the gasification gas is attached to the particles due to temperature drop and separated. A supply device, a particle extraction device for extracting particles in the tar adsorption tower, a temperature detector for detecting the temperature of the gasification gas at the outlet of the tar adsorption tower, and a temperature detected from the temperature detector to be a set temperature. The amount of particles in the tar adsorption tower is adjusted so that the temperature in the tar adsorption tower becomes the set temperature by the adjustment process using the temperature controller that regulates the supply of particles by the particle feeder and the extraction of particles by the particle extraction equipment. A method for removing tar from a gasification gas characterized by adjusting the amount of gas.   The method for removing tar from gasification gas according to claim 1, wherein the gasification gas from a gasification facility which is a two-column gasification furnace is brought into contact with particles.   The gas according to claim 1 or 2, wherein the tar having different components is separated by bringing the gasified gas separated from the tar by contacting with the particles into contact with another kind of particles to separate the tar. Method for removing tar from chemical gas.   The method for removing tar from a gasification gas according to any one of claims 1 to 3, wherein the tar-attached particles are supplied to a gasification facility and the tar is used as a gasification heat source.   The method for removing tar from gasification gas according to any one of claims 1 to 4, wherein the particles are at least one of sand, ash, alumina, and ore.   6. The method for removing tar from gasified gas according to claim 5, wherein the ore having particles is ore and the ore to which tar is attached is used as a reducing agent in the reduction furnace.   A gasification facility, a tar adsorption tower for bringing the gasified gas generated in the gasification facility into contact with particles and attaching tar to the particles, a particle supply device for supplying particles to the tar adsorption tower, and a tar adsorption tower A particle extraction device for extracting particles inside, a temperature detector for detecting the temperature of the gasification gas at the exit of the tar adsorption tower, and a particle supply device for detecting the temperature of the particles by the particle supply device so that the detected temperature from the temperature detector becomes a set temperature. An apparatus for removing tar from gasification gas, comprising: a temperature control device for controlling the temperature in the tar adsorption tower by adjusting supply and particle extraction by the particle extraction device.   A gasification facility includes a fluidized bed combustion furnace, a separator that separates combustion exhaust gas derived from the fluidized bed combustion furnace into a fluidized medium and an exhaust gas, and a fluidized medium separated by the separator is supplied together with the raw material to a fluidized bed. The gasification gas from the gasification gas according to claim 7, wherein the gasification gas is extracted from the gasification gas according to claim 7, wherein the gasification gas is extracted from the gasification gas, and the fluidized medium is supplied to the fluidized bed combustion furnace and circulated. Tar removal device. The apparatus for removing tar from gasification gas according to claim 8, wherein particles extracted from the tar adsorption tower are supplied to the fluidized bed combustion furnace.   The apparatus for removing tar from gasification gas according to any one of claims 7 to 9, comprising a plurality of tar adsorption towers for bringing the gasification gas into contact with particles.

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