JP6647566B2 - Organic matter pyrolysis or gasification system and method, and product gas purification system and method - Google Patents

Description

  One embodiment of the present invention relates to the use of organic waste and biomass as an energy source.

  In recent years, organic wastes such as sludge and waste plastics, and biomass have been actively used as energy sources for effective use of resources and conservation of the global environment. Organic waste and biomass contain organic matter, and when this is thermally decomposed or gasified, combustible gases such as hydrogen, carbon monoxide, methane, and ethane are extracted. These gases are used in vehicles, combustion equipment, power generation devices, hydrogen production devices, and the like. Thermal decomposition or gasification of organic substances is performed by heating in an environment having a low oxygen concentration. As a method for removing tar produced as a by-product at this time, purification (scrubbing) using vegetable oil has been proposed (see Non-Patent Document 1).

"Bioresource Technology", (Netherlands), January 2011, Volume 102, Issue 2, p543-549

  An object of the present invention is to provide a system and a method for efficiently and at low cost purifying a combustible gas obtained by pyrolysis or gasification of organic waste or biomass. Alternatively, one of the objects of the present invention is to provide a system and a method for regenerating an absorbent used in purifying a gas. Alternatively, one of the objects of the present invention is to provide a bubble generating device that can be used in conjunction with the above system and method.

  One of the embodiments of the present invention is a gasifier that generates a combustible gas by heating an organic substance, a scrubber that purifies the combustible gas using an absorbent, and a centrifuge or a filter that absorbs the absorbent. A pyrolysis or gasification system with a regenerator for purification.

  The pyrolysis / gasification system may further include a power generation device that generates power using the combustible gas purified by the scrubber. The pyrolysis or gasification system may further include a pump for circulating the absorbent between the scrubber and the regenerator. The absorbent may be a vegetable oil.

  The scrubber may have a bubble generator that generates bubbles of combustible gas in the absorbent. The scrubber may further include a tank for holding the absorbent and a pump for circulating the absorbent between the tank and the bubble generator. The bubble generator may be configured to generate bubbles having an average diameter of 150 μm or more and 350 μm or less.

  The bubble generator has a tube having an inlet, an outlet, and a throat between the inlet and the outlet of the absorbent, and a gas inlet connected to the throat, and a cross-sectional area of the inlet, an outlet. May be larger than the cross-sectional area of the throat. The tube may have a first portion and a second portion between the inlet and the throat, the first portion including the inlet, the second portion in contact with the throat, and a break in the first portion. The area may be constant in a direction from the inlet to the second portion. The inner wall of the second portion may be inclined with respect to the above direction. The inclination of the inner wall may be constant in the second part.

  One of the embodiments of the present invention is to generate a combustible gas by thermally decomposing or gasifying an organic substance, purify the combustible gas with an absorbent, and centrifuge the absorbent used for purifying the combustible gas. Or a pyrolysis or gasification process involving regeneration by filtration.

  The pyrolysis or gasification method may further include generating power using the purified combustible gas. The pyrolysis or gasification process may further include circulating the regenerated sorbent and purifying the combustible gas with the regenerated sorbent. The absorbent may be a vegetable oil.

  Purifying the combustible gas with the absorbent may include generating bubbles of the combustible gas in the absorbent. The bubbles may be generated such that the average diameter is 150 μm or more and 350 μm or less.

  In the pyrolysis or gasification system and method described above, filtration may be performed by passing the absorbent through a column in which a plurality of alternating first layers and a plurality of second layers are stacked. The first layer may include a material selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, zeolite, and the second layer may include a material selected from polyester, polypropylene, polyurethane. .

1 is a flowchart of a pyrolysis or gasification system according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram of the pyrolysis or gasification system of one Embodiment of this invention. 1 is a schematic view of a gasification furnace of a thermal decomposition or gasification system according to an embodiment of the present invention. 1 is a schematic view of a scrubber and a bubble generator of a thermal decomposition or gasification system according to an embodiment of the present invention. The schematic diagram of the centrifugal separator of the regenerator of the pyrolysis or gasification system of one embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram of the filtration apparatus of the regeneration apparatus of a pyrolysis or gasification system of one Embodiment of this invention. FIG. 2 is a configuration diagram of an experimental device in an example. Schematic diagram and photograph of a centrifuge tube used for centrifugation of an absorbent. A plot of the combustible gas purification time versus the combustible gas tar concentration without regeneration of the absorbent. FIG. 9 is a plot of the flammable gas purification time versus the flammable gas tar concentration when the sorbent is regenerated by centrifugation. FIG. 9 is a plot of the concentration of tar in combustible gas versus the time of combustible gas purification when the regeneration of the absorbent is performed by filtration. Removal efficiency of each light tar component when the regeneration of the absorbent is performed by filtration. Removal efficiency of each light tar component when the regeneration of the absorbent is performed by filtration. Removal efficiency of each light tar component when absorbent is regenerated by centrifugation. Removal efficiency of each light tar component when absorbent is regenerated by centrifugation. FIG. 2 is a schematic diagram of a scrubber using a bubble generator. Photograph of microbubbles generated by a bubble generator. Relationship between the average diameter of microbubbles generated by the bubble generator and the tar removal rate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. However, the present invention can be carried out in various modes without departing from the gist of the present invention, and is not to be construed as being limited to the description of the embodiments exemplified below.

  The drawings may be schematically illustrated in terms of width, thickness, shape, and the like of each portion as compared with actual embodiments in order to make the description clearer, but are merely examples, and the interpretation of the present invention is limited. It does not do. In the present specification and each drawing, elements having the same functions as those described in relation to the already described drawings are denoted by the same reference numerals, and redundant description may be omitted.

  Hereinafter, in this specification and claims, organic waste and biomass are collectively referred to as organic matter. In addition, pyrolysis or gasification is generally referred to as gasification.

(1st Embodiment)
In the present embodiment, a system in which a generator is added to a gasification system will be described as an example of a system that uses organic matter as an energy source.

[1. System flow]
FIG. 1 shows a flowchart of the gasification system. The gasification system includes a step 100 of gasifying organic matter. Specifically, the organic substance is heated at a temperature of about 400 ° C. to 1000 ° C. in the absence of oxygen or in the presence of low-concentration oxygen. The supply amount of oxygen may be about 5% to 50% of the supply amount of oxygen for completely burning the organic matter. By this treatment, a combustible gas containing mainly carbon monoxide and hydrogen (hereinafter, also referred to as synthesis gas) can be obtained.

  The organic matter used is not limited, and includes, for example, thinned wood, pruned waste wood, construction waste wood, agricultural waste, or residues generated during food processing, agricultural waste, textile waste, plastic materials, and the like. Alternatively, it may be rubble including wood, which is generated during a disaster.

  The synthesis gas is a gas at a high temperature, but contains a liquid or solid organic substance as a tar at a normal temperature as tar, which causes blockage of a power generation device and other downstream devices. Therefore, syn gas is purified (scrubbing) to remove tar (step 102). As will be described in detail later, tar is absorbed by the absorbent by a method such as bubbling the synthetic gas to the absorbent or spraying the absorbent on the synthetic gas. When performing bubbling, fine bubbles (microbubbles, microbubbles) of the synthesis gas may be bubbled through the absorbent. The absorbent is preferably a liquid at room temperature and contains an ester of an unsaturated fatty acid and a glycol. Examples of unsaturated fatty acids include erucic acid, oleic acid, ricinoleic acid, linoleic acid and the like. Examples of such absorbents include vegetable oils, and canola oil, castor oil, corn oil, soybean oil, sesame oil, safflower oil and the like can also be used.

  The purified synthesis gas is supplied to a power generator, burned, and the obtained thermal energy is converted into electric power (step 104).

  Further, in the present system, the absorbent used in the purification of the synthesis gas (Step 102) may be recovered and regenerated (Step 106). Although the details will be described later, the tar and the absorbent are separated by centrifugation using the difference in specific gravity between the absorbed tar and the absorbent, and the absorbent is regenerated and reused. Alternatively, the absorbent is regenerated and reused by filtration. This makes it possible to purify the synthesis gas at low cost.

[2. Gasification]
FIG. 2 schematically shows the configuration of the gasification system of the present embodiment. The gasification system uses a gasifier 200 for gasifying organic substances, a purifier (scrubber) 300 for syngas generated by gasification, a regenerator 400 for an absorbent used in the scrubber 300, and a purified syngas. Power generation device 600 that generates electric power by using the power generation device.

  The gasification apparatus 200 has a gasification furnace 206, and the organic matter input from the hopper 202 is sent to the gasification furnace 206 by the feeder 204. Further, air is supplied to the gasification furnace from the inlet 208. Although the gasification furnace 206 shown in FIG. 2 is a downdraft type gasification furnace, an updraft type gasification furnace may be used. The organic matter introduced from the upper part of the gasification furnace 206 is heated in the presence of a low concentration of oxygen to give a flammable synthesis gas and ash or carbide. The synthesis gas taken out from the gas outlet 218 is introduced into the scrubber 300 via the valve 214 and the gas pipe 216. On the other hand, ash or carbide is taken out of the gasification furnace 206 by the discharge conveyor 210 and discharged to the carry-out box 212.

  FIG. 3 shows a schematic diagram of the gasification furnace 206. Organic matter is introduced from the upper opening of the gasification furnace 206, and the organic matter is heated at a temperature of about 400 ° C to 1000 ° C. Energy obtained by burning biomass may be used for heating. Air can be introduced into the gasifier 206 from the inlet 208. The amount of oxygen contained in the supplied air may be about 5% or more and 50% or less with respect to the amount of oxygen required for complete combustion of organic matter.

  The input organic matter forms a raw material layer 220 at the upper part of the gasification furnace 206. Thereafter, the organic substance gradually moves downward by its own weight, and moisture is removed by the high temperature in the gasification furnace 206. This phenomenon mainly occurs in the dry layer 222. Thereafter, the organic matter is thermally decomposed to generate volatile components such as combustible gas and tar. Part of the tar is burned and decomposed at a temperature of about 800 ° C. This phenomenon mainly occurs in the pyrolysis / combustion layer 224. In the lowermost reduction layer 226, a reduction reaction occurs to generate carbon monoxide, hydrogen, methane, or the like as a synthesis gas, and the organic matter becomes ash or carbide. Gasifier 206 has a V-shaped bottom 228 from which ash or carbide is removed from opening 230. On the other hand, the synthesis gas is taken out from a gas outlet 218 provided on the side of the gasification furnace 206 or the like.

[3. Scrubbing]
Syngas contains trace amounts of tar. Tar mainly contains organic compounds that exist as gases at high temperatures, but as liquids or solids at room temperature. The synthesis gas is introduced into the scrubber 300 via a valve 214, a gas pipe 216, etc., and tar is removed in the scrubber 300 (FIG. 2). FIG. 4A is a schematic view of the scrubber 300. As shown in FIG. 4A, the scrubber 300 includes a tank 304, a nozzle 306, a bubble generator 308, a pump 310, a flow meter 312, a pressure gauge 314, and the like.

  The tank 304 has a function of holding the absorbent 302. The tank 304 can include materials such as acrylic resin, polypropylene, polystyrene, and the like. A composite material obtained by mixing these polymer materials and glass fibers may be used. As described above, the absorbent 302 is preferably a liquid that is liquid at normal temperature and contains an ester of an unsaturated fatty acid and a glycol, such as vegetable oil.

  The pump 310 has a function of sucking the absorbent 302 from the tank 304 and transporting it to the bubble generator 308, and further circulating the absorbent 302 to the tank 304 through the nozzle 306. The flow rate of the absorbent 302 is measured by the flow meter 312, and the load on the pump 310 can be estimated by the pressure gauge 314.

  The bubble generator 308 has a function of generating microbubbles of the synthesis gas generated in the gasification furnace 206 in the absorbent 302. The generated microbubbles are transported to the nozzle 306 together with the absorbent 302 and diffused into the absorbent 302. Although not shown, the scrubber 300 may further include a stirring device for stirring the absorbent 302, a temperature control device for keeping the temperature of the absorbent 302 constant, and the like. The synthesis gas may be bubbled into the absorbent 302 in the tank 304 without installing the bubble generator 308 and the pump 310.

  FIG. 4B schematically shows the structure of the bubble generator 308. The bubble generator 308 includes a tube having an inlet 320 and an outlet 322 for the absorbent 302, and a throat 324 between the inlet 320 and the outlet 322. The inner diameter D2 of the throat 324 is smaller than the inner diameter D1 of the outlet 322 and the inner diameter D3 of the inlet 320. The cross-sectional area of the throat 324 is smaller than the cross-sectional areas of the outlet 322 and the inlet 320. The gas inlet 326 is connected to the throat 324. Absorbent 302 transported by pump 310 is supplied to inlet 320. A first part 328 and a second part 330 are provided between the inlet 320 and the throat 324. First portion 328 includes inlet 320 and second portion 330 contacts throat 324. The inner diameter D1 or the cross-sectional area of the first portion 328 can be constant in the direction from the inlet 320 to the second portion 330. On the other hand, the inner wall of the second part 330 is inclined with respect to the direction from the inlet 320 toward the second part 330. Further, the inclination may be constant.

  Due to such a structure of the bubble generating device 308, a minute convection 340 is generated in and around the second portion 330. This convection 340 is transported to the throat 324 together with the absorbent 302.

  At the same time, since a negative pressure is generated in the throat 324, the synthesis gas is sucked from the gas inlet 326 and mixed with the absorbent 302 in the throat 324. The supplied synthesis gas is destroyed by the convection 340 as well as the shear flow of the absorbent 302, giving a large amount of microbubbles 342. The microbubbles 342 are transported to the outlet 322.

  A third portion 332 and a fourth portion 334 are provided between the outlet 322 and the throat 324. Third portion 332 includes outlet 322 and fourth portion 334 contacts throat 324. The inner diameter D3 or the cross-sectional area of the third portion 332 can be constant in the direction from the outlet 322 to the fourth portion 334. On the other hand, the inner wall of the fourth portion 334 is inclined with respect to the direction from the outlet 322 to the fourth portion 334. Further, the inclination may be constant.

  As described in the embodiment, vegetable oil is used as the absorbent 302, and microbubbles 342 are bubbled into the absorbent 302 in the tank 304 using the bubble generator 308, so that the contact area between the absorbent 302 and the syngas is reduced. It increases dramatically, and as a result, tar can be efficiently removed. In particular, by generating microbubbles such that the average diameter of the microbubbles is 150 μm or more and 350 μm or less, tar can be removed with high efficiency.

  Tar contained in the synthesis gas is selectively absorbed and removed by the absorbent 302. After that, the synthesis gas diffused in the tank 304 is taken out from the gas outlet 316. The gasification system according to the present embodiment is configured by burning the synthesis gas and using the obtained energy to generate power using the power generation device 600. The synthesis gas can be used for purposes other than power generation, and may be used for fuel for vehicles, fuel cells, heating, and the like. In this case, the present embodiment can be applied as a fuel generation system, a fuel cell system, or a heating system.

[4. Playback]
The absorbent 302 used in the scrubber 300 absorbs tar in the synthesis gas. Therefore, as the use time and the use frequency increase, the tar absorption capacity decreases. In the gasification system of this embodiment, the tar and the absorbent 302 are separated by the regenerating device 400 to recover the absorbing ability of the absorbent 302, so that the absorbent 302 can be recycled and reused.

  More specifically, the absorbent 302 that has absorbed the tar is transported from the outlet 338 provided in the tank 304 to the regenerating apparatus 400 via a pump 402, a valve 404, or the like having an arbitrary configuration (FIG. 2, 4). In the regenerator 400, tar is removed from the absorbent 302 using centrifugation or filtration.

[4-1. Centrifugal separation]
The configuration of the centrifuge for regenerating the absorbent 302 can be arbitrarily selected, and an example is shown in FIG. The centrifuge 406 schematically illustrated in FIG. 5 can include a rotating body 410, a rotating shaft 412, a supply unit 414, a scraper 418, a shutter 420, and the like. The rotating shaft 412 is connected to a motor (not shown), and transmits the rotating force of the motor to the rotating body 410. The rotating body 410 is driven by a motor and rotates about a rotating shaft 412. A supply section 414 is provided near the center of the rotating body 410, and the absorbent 302 that has absorbed the tar is supplied from an outlet 416 provided in the supply section 414 toward the inner wall of the rotating body 410. The rotating body 410 has openings 422 and 424 on the upper surface and the bottom surface, respectively. The opening 424 located on the bottom surface of the rotating body 410 is provided with a shutter 420 for controlling opening and closing thereof. Although not shown, a shutter for controlling opening and closing of the opening 422 may be provided.

  After the absorbent 302 is supplied, the rotating body 410 is rotated. The rotation speed is arbitrary, but may be, for example, from 1,000 rpm to 30,000 rpm, or from 5,000 rpm to 10,000 rpm. Centrifugal force generated by the rotation of the rotating body 410 is applied to the absorbent 302, and the tar and the absorbent 302 are separated due to a difference in specific gravity. Since the specific gravity of the tar is larger than that of the absorbent 302, the tar is deposited on the inner wall of the rotating body 410. On the other hand, the absorbent 302 from which the tar has been removed is discharged from the opening 422, collected, transported to the tank 304 of the scrubber 300 via a pump 430, a valve 432, and the like (FIG. 2), and reused for syngas purification. . Accordingly, the absorbent 302 can be used repeatedly, and tar can be removed from the synthesis gas at low cost.

  On the other hand, the tar deposited on the inner wall of the rotating body 410 is removed by the scraper 418. Specifically, the scraper 418 is moved so as to be in contact with the inner wall of the rotating body 410, and at the same time, the rotating body 410 is rotated at a low speed. As a result, the tar peels off from the inner wall of the rotating body 410 and is collected on the bottom surface of the rotating body 410. Thereafter, the shutter 420 is opened, and the tar is discharged from the opening 424. The absorbent 302 is circulated between the scrubber 300 and the regenerating device 400 by the pump 402 or the pump 430.

  In this manner, centrifugal force is applied to the absorbent 302 by rotating the rotating body 410 holding the absorbent 302, the separated tar is discharged from the bottom surface of the rotating body 410, and the purified absorbent 302 is removed from the rotating body 410. The absorbent 302 can be continuously regenerated by collecting the absorbent 302 from the upper surface. In addition, if the tar deposited on the inner wall does not fall to the bottom surface of the rotating body 410 in a short time even when the rotation of the rotating body 410 is stopped due to the high viscosity of the tar, a separate opening is formed on the bottom surface of the rotating body 410. And the purified absorbent 302 may be recovered therefrom.

[4-2. filtration]
The filtration for regenerating the absorbent 302 can be performed by various methods, one example of which is shown in FIG. The filtering device 450 shown in FIG. 6 has a column 452, and the absorbent 302 containing tar is introduced from the upper part of the column 452. A container 458 for receiving the absorbent 302 after filtration is provided below the column 452. Container 458 may be connected to a vacuum pump or aspirator 462 via valve 460. Accordingly, the pressure in the container 458 can be reduced, and the absorbent 302 can be filtered at a high speed. Although not shown, pressure may be applied to the absorbent 302 from above the column 452 to accelerate the filtration.

  The column 452 can be provided with a plurality of alternating first layers 454 and second layers 456. FIG. 6 illustrates an example in which two first layers 454_1 and 454_2 and two second layers 456_1 and 456_2 are provided. However, the numbers of the first layers 454 and the second layers 456 are not limited. And may be different from each other.

  The first layer 454 can include a sandy material, which can be selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, zeolite, and the like. The average particle size of the material can be from 0.2 mm to 2.0 mm, from 0.5 mm to 1.5 mm, or from 0.7 mm to 0.9 mm. The thickness of the first layer 454 depends on the size of the column 452, but can be 1 cm or more and 5 cm or less, typically about 3 cm. The first layer 454 has a function of preventing clogging of the second layer 456 and maintaining a filtration rate.

  The second layer 456 can include a fibrous material, and the material can be selected from polymeric materials such as polyester, polyurethane, polypropylene, and the like. The thickness of the second layer 456 depends on the size of the column 452, but can be 4 cm or more and 10 cm or less, typically about 7 cm. The second layer 456 has a function of removing insoluble fine particles mixed into the absorbent 302, and has a particularly high effect on removing fine particles having a particle size of 30 μm or more.

  As described above, in the gasification system of the present embodiment, a combustible synthesis gas is extracted by gasifying organic substances including various kinds of materials and having various shapes, for example, contained in rubble. be able to. Furthermore, by using vegetable oil as the absorbent and introducing the syngas into the absorbent as microbubbles, tar in the syngas can be efficiently removed. For this reason, damage to equipment such as a power generator using the synthesis gas can be significantly reduced. Furthermore, the tar can be easily removed by centrifuging or filtering the absorbent that has absorbed the tar. Therefore, the absorbent can be easily regenerated and reused, and the synthesis gas can be purified at low cost.

  In the present embodiment, the form in which energy from organic matter is used for power generation has been described, but energy from organic matter may be used for purposes other than power generation. For example, a fuel cell system using hydrogen contained in gas, a heating system using heat obtained by burning gas as a direct heat source, and the like are also embodiments of the present invention.

  In the present embodiment, a result of evaluating regeneration of the absorbent 302 by centrifugation will be described. The evaluation method will be described with reference to FIGS. FIG. 7 is a schematic diagram of the apparatus used in this embodiment. Japanese cedar chips (size: 0.5 mm to 1 mm), which had been dried at 105 ° C. for 2 hours as an organic substance, were introduced into the heating furnace 504 at a rate of 0.6 g / min using a hopper 500 and a screw feeder 502. The heating furnace 504 is made of stainless steel, has a diameter of 30 mm, and a height of 280 mm. Tables 1 and 2 show the fuel characteristics of the chips used. Table 1 shows the results of elemental analysis, and Table 2 shows the results of industrial analysis based on JIS M8814 standards.

  Nitrogen was supplied from a nitrogen cylinder 506 via a valve 508 at a flow rate of 0.8 L / min as a carrier gas, and the chip was heated at 800 ° C. in a heating furnace 504 to generate a synthesis gas. The temperature of the heating furnace 504 was monitored by a thermocouple 510.

  Using a carrier gas, the synthesis gas was introduced into a three-necked wolf bottle 522 filled with 500 mL of canola oil as the absorbent 302. The introduction of the synthesis gas was performed by bubbling the absorbent 302 with stirring (1000 rpm) using a magnetic stirrer 524. The three-necked wolf bottle 522 was set in a thermostat 520 maintained at a constant temperature (30 ° C.) using a thermometer 530 and a temperature controller 528. The valve 532 switches the synthesis gas, whereby the synthesis gas before scrubbing and the synthesis gas after scrubbing are introduced into the sampling unit 540, respectively. The amount of tar absorbed by the absorbent 302 was estimated from the difference in the amount of tar contained in these gases. Heavy tar and light tar were measured by a wet method and a dry method, respectively. The details of the measurement method are described in Non-Patent Document 1 and the documents cited therein, and are therefore omitted.

  After scrubbing the synthesis gas, the absorbent 302 and tar were separated using a centrifuge 526. Specifically, as shown in FIG. 8A, 80 mL of an absorbent was added to a centrifuge tube, and centrifugation was performed at a rotation speed of 10,000 rpm for 30 minutes. As a result, as schematically shown in FIG. 8 (B), it was confirmed that tar was deposited on the bottom of the centrifuge tube and separated from the supernatant absorbent 302. A photograph of the centrifuge tube at this time is shown in FIG. As shown by the dotted line in FIG. 8 (C), it can be seen that tar is deposited on the bottom of the centrifuge tube.

  The regeneration effect of the absorbent 302 using the centrifuge 526 was evaluated by the following method. First, the tar concentration of the scrubbed synthesis gas was monitored for 135 minutes. Thereafter, the absorbent 302 was centrifuged to remove tar, and the absorbent 302 was regenerated. Subsequently, the tar concentration of the synthesis gas scrubbed using the regenerated absorbent 302 was monitored for 135 minutes. Hereinafter, similarly, the regeneration of the absorbent 302 and the measurement of the tar concentration of the scrubbed synthesis gas were repeated. For comparison, the tar concentration in the synthesis gas when scrubbing was performed for 10 hours continuously without performing the regeneration operation was also measured. The results are shown in FIGS.

FIG. 9 shows an experimental result when the regeneration operation of the absorbent 302 is not performed. The curve 550 in FIG. 9 is the result of measuring the tar concentration of the syngas that has not been scrubbed, which shows that the syngas contains tar at a concentration of about 30 g / m ³ . Curve 552 shows the concentration of tar contained in the synthesis gas after scrubbing, and the bar graph shows the tar removal rate, that is, the ratio of the tar removed by scrubbing to the tar contained in the synthesis gas. It can be seen from the curve 552 and the bar graph that almost all of the tar has been removed immediately after the start of scrubbing. However, it was found that the tar removal rate decreased with the passage of time, was saturated at about 30% after 7 hours, and the tar removal ability of the absorbent 302 did not change significantly thereafter. When the absorbent 302 was not regenerated, it was confirmed that the amount of tar that could be absorbed by 1 L of the absorbent 302 remained under 16.6 g under this condition.

In contrast, FIG. 10 shows the results when the absorbent 302 was purified and regenerated by centrifugation every 135 minutes. Curve 562 shows the concentration of tar contained in the synthesis gas after scrubbing, and the bar graph shows the tar removal rate. Similar to FIG. 9, it can be seen that the synthesis gas contains tar at a constant concentration of about 30 g / m ³ , as shown by the curve 560. 100 minutes after the start of scrubbing, the tar removal rate dropped to 76% (see bar graph). However, it was found that when the absorbent 302 was regenerated, the tar removal rate recovered to 96% as shown by the bar graph and the curve 562 (see the arrow in the figure). Thereafter, regeneration was performed three times, and it was found that each of the regenerations showed a tar removal rate comparable to the initial tar removal rate (98% to 93%) after the regeneration. In this series of experiments, it was confirmed that 28.8 g of tar was absorbed by 1 L of the absorbent 302.

  In this embodiment, the result of evaluating the regeneration of the absorbent 302 by filtration will be described. The evaluation method was the same as in Example 1. The tar concentration of the scrubbed synthesis gas was monitored for 135 minutes, and then the absorbent 302 was filtered to remove the tar and the absorbent 302 was regenerated. The filtration was performed using the filtration device 450 shown in FIG. Here, in the column 452 (6.5 cm in diameter), a second layer 456 (thickness 7 cm) containing polyester and a first layer 454 (thickness 3 cm) containing silica gel are two layers in order from the top. The layers were alternately laminated. Subsequently, the tar concentration of the synthesis gas scrubbed using the regenerated absorbent 302 was monitored for 135 minutes. Hereinafter, similarly, the regeneration of the absorbent 302 and the measurement of the tar concentration of the scrubbed synthesis gas were repeated. The results are shown in FIG.

As shown by the curve 570, it can be seen that the synthesis gas contains tar at a constant concentration of about 30 g / m ³ . Further, similarly to the result shown in FIG. 9, the tar removal rate decreased to 73% 100 minutes after the start of scrubbing (see the bar graph). However, it was found that when the absorbent 302 was regenerated, the tar removal rate recovered to 96% as shown by the bar graph and the curve 572 (see the arrow in the figure). Thereafter, regeneration was performed three times, and it was found that all of them showed tar removal rates comparable to the initial tar removal rates (96% to 91%) after the regeneration. In this series of experiments, it was confirmed that 26.8 g of tar was absorbed by 1 L of the absorbent 302.

  The results of Examples 1 and 2 indicate that the tar absorbed by the absorbent 302 can be removed by centrifugation or filtration, and that the absorbent 302 regenerated by removing the tar almost completely has the initial absorption capacity. It has been confirmed that it will recover. Therefore, it can be said that the gasification system disclosed in the embodiment of the present invention can efficiently and at low cost remove tar from synthesis gas.

  In this example, vegetable oil is used as an absorbent, and the performance of removing light tar components with respect to absorption and regeneration of synthesis gas is described. The experiment was performed by using the system described in Example 1 and monitoring the concentrations of benzene, toluene, phenol, indene, and naphthalene in the synthesis gas before and after scrubbing, respectively. The structural formulas of these compounds are shown below. As in the case of Examples 1 and 2, canola oil was used as the vegetable oil. The regeneration treatment was performed by filtration or centrifugation every 135 minutes, as in Examples 1 and 2.

  FIGS. 12 and 13 show the results when filtration was performed as a regeneration method. These figures show the change over time in the concentration of each component of light tar in the synthesis gas before purification and in the synthesis gas after scrubbing.

  For example, in the case of an aromatic hydrocarbon having only one benzene ring such as benzene or toluene, or a compound having a polar group (hydroxyl group) such as phenol, scrubbing is performed as shown in FIGS. Although a high tar removal rate was exhibited at the initial stage, the removal rate hardly recovered even by the regeneration operation every 135 minutes, and it was found that the removal rate gradually decreased with the time for scrubbing.

  On the other hand, in the case of a polycyclic hydrocarbon such as indene or a polycyclic aromatic compound such as naphthalene, the removal efficiency is higher than that of benzene, toluene, or phenol.For example, in the case of naphthalene, at least the second regeneration Previously, it was found that it could be almost completely removed.

  FIGS. 14 and 15 show the results when centrifugation was performed as a regeneration method. In the case of benzene, toluene, and phenol, as in the case of the regeneration by filtration, as shown in FIGS. The rate did not recover much, and it was found that the removal rate gradually decreased with the time of scrubbing.

  On the other hand, it was found that the indene and naphthalene had a large regeneration effect by centrifugation. For example, as shown in FIG. 15A, no noticeable decrease in the indene removal rate was observed from the start of scrubbing to before the regeneration, and almost the initial removal rate was restored by each regeneration operation. In the case of naphthalene, it was found that almost the entire amount could be removed over an experiment time of 10 hours (FIG. 15 (B)).

  These results suggest that the removal of tar by vegetable oil and the regeneration of vegetable oil by filtration or centrifugation are effective for tar components having relatively high molecular weight among light tar components. Highly volatile substances such as benzene and toluene do not place a heavy burden on equipment such as power generation equipment, but solids at room temperature or high-boiling substances such as naphthalene and indene can cause blockage of equipment. Absent. Therefore, by applying the gasification system and the gasification method of the embodiment of the present invention, it is possible to reduce the blockage load on various facilities for burning the synthesis gas, and it is possible to extend the life of the facilities.

  In this embodiment, the effect of microbubbles on scrubbing will be described. The experiment was performed using the apparatus shown in FIG. Specifically, canola oil was filled in an acrylic tank 304 as an absorbent 302. The absorbent 302 in the tank 304 was suctioned using the pump 310, transported to the bubble generator 308, and circulated to the tank 304 again. At the same time, air was introduced into the bubble generator 308 via the valve 318, and the air was diffused as fine bubbles from the nozzle 306 in the tank 304 into the absorbent 302. The flow rate of the absorbent 302 was measured by the flow meter 312, and the load applied to the pump 310 was estimated by the pressure gauge 314. In the experiment, three types of bubble generators 308 having different inner diameters D2 (R = D2 / D1) of the throat 324 with respect to the inner diameter D1 of the inlet 320 were used (see FIG. 4B).

FIG. 17 shows a photograph of microbubbles generated in such an experimental apparatus. FIG. 17 shows a photograph of microbubbles when the bubble generator 308 having R of 0.17, 0.47, and 0.67 is used. The microbubbles were found to have an average diameter (D _ave ) of about 200 μm to 300 μm, depending on the flow rate of the absorbent 302 in the throat 324 as well as the amount of air introduced.

Here, as shown in FIG. 16, an area of 8 mm × 11 mm where one side is located at a height of 10 cm from the bottom of the tank 304 was observed, and the area of the microbubbles occupied in this area (88 mm ² ) The average diameter of the microbubbles was calculated. As a result, it was found that the average diameter of the microbubbles was 298 μm, 197 μm, and 263 μm when R was 0.17, 0.47, and 0.67, respectively.

  Using the apparatus of this example, synthesis gas was introduced instead of air, and the dependence of the average diameter of the microbubbles on the tar removal rate was evaluated. The results are shown in FIG. The comparative example of FIG. 18 shows the result when the synthesis gas is bubbled in the absorbent 302 without using the bubble generator 308 under the same conditions. As can be seen from FIG. 18, it was confirmed that the tar removal rate was significantly improved by bubbling the synthesis gas as microbubbles using the bubble generator 308. Further, it was found that the tar removal rate increased as the average diameter of the microbubbles became smaller, and the tar removal rate reached 97.7% when the average diameter was 197 μm. Therefore, as shown in this example, it can be said that by setting various conditions so that the average diameter of the microbubbles becomes small, it is possible to achieve highly efficient tar removal.

  The embodiments described above as embodiments of the present invention can be implemented in appropriate combinations as long as they do not conflict with each other. Those in which a person skilled in the art appropriately adds, deletes or changes the design based on each embodiment are also included in the scope of the present invention as long as they have the gist of the present invention.

  Naturally, the present invention is not limited to the effects and advantages that are different from the advantages provided by the above-described embodiments and that are obvious from the description of the present specification or can be easily predicted by those skilled in the art. It is understood that it is brought by.

  100: step, 102: step, 104: step, 106: step, 200: gasifier, 202: hopper, 204: feeder, 206: gasifier, 208: inlet, 210: discharge conveyor, 212: carry-out box , 214: Valve, 216: Gas pipe, 218: Gas outlet, 220: Raw material layer, 222: Dry layer, 224: Combustion layer, 226: Reduction layer, 228: Bottom, 230: Opening, 300: Scrubber, 302 : Absorbent, 304: tank, 306: nozzle, 308: bubble generator, 310: pump, 312: flow meter, 314: pressure gauge, 316: gas outlet, 318: valve, 320: inlet, 322: exhaust Outlet, 324: throat, 326: gas inlet, 328: first part, 330: second part, 332: third Part, 334: fourth part, 338: outlet, 340: convection, 342: microbubble, 400: regenerator, 402: pump, 404: valve, 406: centrifuge, 410: rotating body, 412: rotation Shafts, 414: supply unit, 416: discharge port, 418: scraper, 420: shutter, 422: opening, 424: opening, 430: pump, 432: valve, 450: filtration device, 452: column, 454: No. 1st layer, 456: second layer, 458: container, 460: valve, 462: aspirator, 500: hopper, 502: screw feeder, 504: heating furnace, 506: nitrogen cylinder, 508: valve, 510: thermocouple 520: constant temperature bath, 522: three-necked wolf bottle, 524: magnetic stirrer, 526: centrifugal separator, 528: temperature control , 530: Thermometer, 532: Valve, 540: sampling unit, 550: curve 552: curve 560: curve 562: curve 570: curve 572: curve 600: power generator

Claims (13)

A gasifier that generates combustible gas by heating organic matter;
A scrubber for purifying the combustible gas using an absorbent;
Having a regenerating device to purify the absorbent by centrifugation or filtration,
The scrubber has a bubble generator for generating bubbles of the combustible gas having an average diameter of 300 μm or less in the absorbent,
The pyrolysis or gasification system, wherein the absorbent is a vegetable oil.   The pyrolysis or gasification system according to claim 1, further comprising a power generation device that generates power using the combustible gas processed by the scrubber.   2. The pyrolysis or gasification system according to claim 1, further comprising a pump for circulating the absorbent between the scrubber and the regenerator. The pyrolysis or gasification system according to claim 1 , wherein the scrubber further comprises a tank for holding the absorbent and a pump for circulating the absorbent between the tank and the bubble generator. The bubble generator,
A tube having an inlet and an outlet for the absorbent, and a throat between the inlet and the outlet;
Having a gas inlet connected to the throat,
The cross-sectional area of the inlet cross-sectional area of the outlet is larger than the cross-sectional area of the throat, pyrolysis or gasification system of claim 1. The tube has a first portion and a second portion between the inlet and the throat,
The first portion includes the inlet, the second portion contacts the throat,
The pyrolysis or gasification system according to claim 5 , wherein a cross-sectional area of the first part is constant in a direction from the inlet to the second part. 7. The pyrolysis or gasification system according to claim 6 , wherein the inner wall of the second part is inclined with respect to the direction. The pyrolysis or gasification system according to claim 7 , wherein the inclination of the inner wall is constant in the second part. The filtration is performed by passing the absorbent through a column in which a plurality of alternating first layers and a plurality of second layers are stacked,
The first layer includes a material selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, and zeolite;
The pyrolysis or gasification system according to claim 1, wherein the second layer comprises a material selected from polyester, polypropylene, polyurethane. Combustible gas is produced by gasifying organic matter,
Purifying the combustible gas with an absorbent,
Centrifuging the absorbent used for the purification of the combustible gas, or includes regenerating by filtration,
Purification of the combustible gas is performed by generating bubbles of the combustible gas having an average diameter of 300 μm or less in the absorbent.
The thermal decomposition or gasification method, wherein the absorbent is a vegetable oil. The method of claim 10 , further comprising generating electricity using the purified combustible gas. The method according to claim 10 , wherein the regenerated absorbent is circulated, and the combustible gas is purified by the regenerated absorbent. The filtration is performed by passing the absorbent through a column in which a plurality of alternating first layers and a plurality of second layers are stacked,
The first layer includes a material selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, and zeolite;
The method of claim 10 , wherein the second layer comprises a material selected from polyester, polypropylene, and polyurethane.