JP2017222735A - System and method for pyrolysis or gasification of organic matter, and system and method for purification of generated gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method for efficiently purifying combustible gas at a low cost, the gas being obtained by pyrolysis or gasification of organic matter such as organic waste and biomass.SOLUTION: A pyrolysis or gasification system is provided that comprises: a gasification furnace generating combustible gas by heating organic matter; a scrubber for purifying the combustible gas using an absorbent; and a regeneration device purifying the adsorbent by centrifugation or filtration. The pyrolysis or gasification system may further comprise a power generation device that generates electricity by using the combustible gas purified by the scrubber. The pyrolysis or gasification system may further comprise a pump which circulates the adsorbent between the scrubber and regeneration device. The adsorbent may be a vegetable oil.SELECTED DRAWING: Figure 2

Description

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

  In recent years, organic waste such as sludge and waste plastic, or biomass has been actively used as an energy source for effective use of resources and preservation of the global environment. Organic waste and biomass contain organic matter, and when this is pyrolyzed 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 with a low oxygen concentration. As a method for removing the by-product tar at this time, refinement (scrubbing) using vegetable oil has been proposed (see Non-Patent Document 1).

"Bioresources Technology", (Netherlands), January 2011, Vol. 102, No. 2, p543-549

  One of the objects of the present invention is to provide a system and method for purifying combustible gas obtained by thermal decomposition or gasification of organic waste or biomass efficiently and at low cost. Alternatively, one of the objects of the present invention is to provide a system and method for regenerating an absorbent used for gas purification. 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 includes a gasification furnace that generates a combustible gas by heating organic matter, a scrubber that purifies the combustible gas using an absorbent, and the absorbent by centrifugation or filtration. A pyrolysis or gasification system having a regenerator for purification.

  The pyrolysis / gasification system may further include a power generation device that generates power using a combustible gas purified by a scrubber. The pyrolysis or gasification system may further comprise 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 generating device that generates bubbles of combustible gas in the absorbent. The scrubber may further include a tank that holds the absorbent and a pump that circulates the absorbent between the tank and the bubble generating device. The bubble generating device may be configured to generate bubbles having an average diameter of 150 μm or more and 350 μm or less.

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

  In one embodiment of the present invention, combustible gas is generated by pyrolyzing or gasifying an organic substance, the combustible gas is purified with an absorbent, and the absorbent used for purification of the combustible gas is centrifuged. Or a pyrolysis or gasification process involving regeneration by filtration.

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

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

  In the above pyrolysis or gasification system and method, filtration may be performed by passing an absorbent through a column in which a plurality of alternating first and 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. .

The flowchart of the thermal decomposition or gasification system of one Embodiment of this invention. The schematic diagram of the thermal decomposition or gasification system of one Embodiment of this invention. The schematic diagram of the gasification furnace of the thermal decomposition or gasification system of one Embodiment of this invention. The schematic diagram of the scrubber of the thermal decomposition or gasification system of one Embodiment of this invention, and a bubble generator. The schematic diagram of the centrifuge of the reproducing | regenerating apparatus of the thermal decomposition or gasification system of one Embodiment of this invention. The schematic diagram of the filtration apparatus of the reproducing | regenerating apparatus of the thermal decomposition or gasification system of one Embodiment of this invention. The block diagram of the experimental apparatus in an Example. Schematic diagram and photograph of a centrifuge tube used for centrifugal separation of absorbent. Plot of tar concentration in combustible gas versus combustible gas purification time without absorbent regeneration. Plot of tar concentration in combustible gas against combustible gas purification time when absorbent regeneration is performed by centrifugation. Plot of tar concentration in combustible gas versus combustible gas purification time when absorbent regeneration is performed by filtration. Removal efficiency of each light tar component when absorbent is regenerated by filtration. Removal efficiency of each light tar component when absorbent is regenerated 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. The schematic diagram of the scrubber using a bubble generator. A photograph of microbubbles generated by a bubble generator. The relationship between the average diameter of microbubbles generated by a bubble generator and the tar removal rate.

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

  In order to make the explanation clearer, the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part as compared to the actual embodiment, but are merely examples and limit the interpretation of the present invention. Not what you want. In this specification and each drawing, elements having the same functions as those described with reference to the previous drawings may be denoted by the same reference numerals, and redundant description may be omitted.

  Hereinafter, in the present specification and claims, organic waste and biomass are collectively referred to as organic matter. Further, pyrolysis or gasification is generally referred to as gasification.

(First embodiment)
In this embodiment, a system in which a generator is added to a gasification system will be described as an example of a system that uses an organic substance as an energy source.

[1. System flow]
FIG. 1 shows a flowchart of the gasification system. The gasification system includes a step 100 for 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 a low concentration of oxygen. The oxygen supply amount may be a supply amount of about 5% to 50% with respect to the oxygen supply amount for completely burning the organic matter. By this treatment, a combustible gas mainly containing carbon monoxide and hydrogen (hereinafter also referred to as synthesis gas) can be obtained.

  There are no limitations on the organic matter used, and examples include thinned wood, pruning waste, building waste wood, agricultural waste, or residues generated during food processing, agricultural waste, textile waste, plastic materials, and the like. Alternatively, it may be rubble containing wood that is generated at the time of a disaster.

  Syngas contains organic substances that are gases at high temperatures but are liquid or solid at normal temperatures as tars, which can cause clogging of power generation devices and other downstream equipment. Therefore, the synthesis gas is purified (scrubbed) to remove tar (step 102). Although details will be described later, tar is absorbed into the absorbent by a method such as bubbling the synthetic gas to the absorbent or spraying the absorbent with respect to the synthetic gas. When bubbling is performed, fine bubbles (microbubbles, microbubbles) of synthesis gas may be bubbled through the absorbent. As the absorbent, those which are liquid at normal temperature and contain an ester of unsaturated fatty acid and glycol are preferable. Examples of unsaturated fatty acids include erucic acid, oleic acid, ricinoleic acid, linoleic acid, and the like. An example of such an absorbent is vegetable oil, and canola oil, castor oil, corn oil, soybean oil, sesame oil, safflower oil, and the like can also be used.

  The refined synthesis gas is supplied to the 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 synthesis gas purification (step 102) may be recovered and regenerated (step 106). Although details will be described later, utilizing the difference in specific gravity between the absorbed tar and the absorbent, the tar and the absorbent are separated by centrifugation, and the absorbent is regenerated and reused. Alternatively, the absorbent is regenerated and reused by filtration. Thereby, the synthesis gas can be purified at a low cost.

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

  The gasification apparatus 200 includes a gasification furnace 206, and the organic matter charged from the hopper 202 is sent to the gasification furnace 206 by the feeder 204. Air is supplied from the inlet 208 to the gasifier. The gasification furnace 206 shown in FIG. 2 is a downdraft type gasification furnace, but an updraft type gasification furnace may be used. The organic substance introduced from the upper part of the gasification furnace 206 is heated in the presence of a low concentration of oxygen to give combustible synthesis gas and ash or carbide. The synthesis gas taken out from the gas outlet 218 is introduced into the scrubber 300 through the valve 214 and the gas pipe 216. On the other hand, ash or carbide is taken out from 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. An organic substance is introduced through an opening at the top of the gasification furnace 206, and the organic substance is heated at a temperature of about 400 ° C to 1000 ° C. For heating, energy obtained by burning biomass may be used. Air can be introduced into the gasification furnace 206 from the introduction port 208. The amount of oxygen contained in the supplied air may be about 5% to 50% with respect to the amount of oxygen necessary for complete combustion of the organic matter.

  The input organic matter forms a raw material layer 220 in the upper part of the gasification furnace 206. Thereafter, the organic matter gradually moves downward due to 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. A part of the tar is burned and decomposed at a temperature around 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, which is a synthesis gas, and the organic matter becomes ash or carbide. The gasification furnace 206 has a V-shaped bottom portion 228 from which ash or carbide is taken out. On the other hand, the synthesis gas is taken out from a gas outlet 218 provided on the side surface of the gasification furnace 206 or the like.

[3. Scrubbing]
The synthesis gas contains a trace amount of tar. Tar mainly contains an organic compound that exists as a gas at a high temperature but exists as a liquid or a solid at a normal temperature. The synthesis gas is introduced into the scrubber 300 through the valve 214, the gas pipe 216, etc., and tar is removed in the scrubber 300 (FIG. 2). FIG. 4A shows a schematic diagram 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, and polystyrene. You may use the composite material which mixed these polymeric materials and glass fiber. As described above, the absorbent 302 is preferably liquid at room temperature and containing an unsaturated fatty acid and an ester of glycol. An example is vegetable oil.

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

  The bubble generator 308 has a function of generating fine bubbles 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 generating device 308 or the pump 310.

  The structure of the bubble generator 308 is schematically shown in FIG. The bubble generating device 308 has a tube having an inlet 320 of the absorbent 302, an outlet 322, 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 discharge port 322 and the inner diameter D3 of the injection port 320. The cross-sectional area of the throat 324 is smaller than the cross-sectional areas of the discharge port 322 and the injection port 320. A gas inlet 326 is connected to the throat 324. The absorbent 302 transported by the pump 310 is supplied to the inlet 320. A first portion 328 and a second portion 330 are provided between the inlet 320 and the throat 324. The first portion 328 includes the inlet 320 and the second portion 330 contacts the throat 324. The inner diameter D <b> 1 or the cross-sectional area of the first portion 328 can be made constant in the direction from the inlet 320 toward the second portion 330. On the other hand, the inner wall of the second portion 330 is inclined with respect to the direction from the inlet 320 toward the second portion 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 the second portion 330 and its periphery. This convection 340 is transported along with the absorbent 302 to the throat 324.

  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 broken 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 discharge port 322.

  A third portion 332 and a fourth portion 334 are provided between the discharge port 322 and the throat 324. The third portion 332 includes a discharge port 322 and the fourth portion 334 contacts the throat 324. The inner diameter D3 or the cross-sectional area of the third portion 332 can be constant in the direction from the discharge port 322 toward 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 discharge port 322 toward the fourth portion 334. Further, the inclination may be constant.

  As will be described in the embodiment, vegetable oil is used as the absorbent 302, and bubbles 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 synthesis gas is increased. As a result, the tar can be efficiently removed. In particular, by generating microbubbles so 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. Thereafter, the synthesis gas diffused in the tank 304 is taken out from the gas outlet 316. The gasification system which is this embodiment is comprised by burning synthetic gas and generating electric power with the electric power generating apparatus 600 using the obtained energy. Syngas 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. Regeneration]
The absorbent 302 used in the scrubber 300 absorbs tar in the synthesis gas. Therefore, as the usage time and usage frequency increase, the tar absorption capacity decreases. In the gasification system of the present embodiment, the absorbent 302 can be regenerated and reused by separating the tar and the absorbent 302 with the regenerator 400 and recovering the absorbent capacity of the absorbent 302.

  More specifically, the absorbent 302 that has absorbed tar is transported from the take-out port 338 provided in the tank 304 to the regenerator 400 via a pump 402, a valve 404, and the like having any configuration (FIG. 2, 4). In the regenerator 400, the tar is removed from the absorbent 302 using centrifugation or filtration.

[4-1. Centrifuge]
The configuration of the centrifuge for regeneration of the absorbent 302 can be arbitrarily selected, and an example thereof 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 rotational force of the motor to the rotating body 410. The rotating body 410 is driven by a motor and rotates about the rotating shaft 412. A supply unit 414 is provided near the center of the rotating body 410, and the absorbent 302 that has absorbed tar is supplied toward the inner wall of the rotating body 410 from the discharge port 416 provided in the supplying unit 414. The rotating body 410 has openings 422 and 424 on the top 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 that controls opening and closing thereof. Although not illustrated, 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 set to, for example, 1000 rpm to 30000 rpm, or 5000 rpm to 10000 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 by the difference in specific gravity. Since tar has a higher specific gravity than 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 tar has been removed is discharged and collected from the opening 422, transported to the tank 304 of the scrubber 300 via the pump 430, the valve 432, and the like (FIG. 2), and used again for the purification of the synthesis gas. . As a result, 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 accumulated on the inner wall of the rotating body 410 is removed by the scraper 418. Specifically, the scraper 418 is moved so as to contact the inner wall of the rotating body 410, and at the same time, the rotating body 410 is rotated at a low speed. Thereby, tar is peeled off from the inner wall of the rotating body 410 and collected on the bottom surface of the rotating body 410. Thereafter, the shutter 420 is opened, and tar is discharged from the opening 424. The absorbent 302 is circulated between the scrubber 300 and the regenerator 400 by the pump 402 or the pump 430.

  Thus, by rotating the rotating body 410 that holds the absorbent 302, centrifugal force is applied to the absorbent 302, the separated tar is discharged from the bottom surface of the rotating body 410, and the purified absorbent 302 is supplied to the rotating body 410. The absorbent 302 can be continuously regenerated by collecting from the upper surface of the material. Note that if the tar viscosity is high and the tar accumulated on the inner wall does not fall on the bottom surface of the rotating body 410 in a short time even when the rotation of the rotating body 410 is stopped, a separate opening is provided 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, an example of which is shown in FIG. The filtration device 450 shown in FIG. 6 has a column 452, and the absorbent 302 containing tar is introduced from the top of the column 452. A container 458 for receiving the filtered absorbent 302 is provided under the column 452. Container 458 may be connected to vacuum pump or aspirator 462 via valve 460. Thereby, the inside of the container 458 can be depressurized, and the absorbent 302 can be filtered at a high speed. Although not shown, filtration may be accelerated by applying pressure to the absorbent 302 from above the column 452.

  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 number of the first layers 454 and the second layers 456 is 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 the 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 in the absorbent 302, and has a particularly high effect for removing fine particles having a particle diameter of 30 μm or more.

  As described above, in the gasification system according to the present embodiment, combustible synthesis gas is extracted by gasifying organic substances having various shapes including various materials such as those contained in rubble. be able to. Furthermore, tar in the synthesis gas can be efficiently removed by using vegetable oil as the absorbent and introducing the synthesis gas into the absorbent as fine bubbles. For this reason, damage to facilities, such as a power generator using syngas, can be reduced significantly. Further, 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 a low cost.

  In this embodiment, although the form which utilizes the energy from organic substance for electric power generation was described, you may utilize the energy of organic substance for uses other than electric power generation. For example, a fuel cell system that uses hydrogen contained in a gas, a heating system that uses heat obtained by burning gas as a direct heat source, and the like are also embodiments of the present invention.

  In this example, the results of evaluating the 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 example. Japanese cedar chips (size: 0.5 mm to 1 mm) that had been dried at 105 ° C. for 2 hours in advance as an organic substance were put into a 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, and 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 elemental analysis results, and Table 2 shows the industrial analysis results based on the standard of JIS M 8814.

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

  The carrier gas was used to introduce the synthesis gas into the three-necked wolf bottle 522 filled with 500 mL of canola oil as the absorbent 302. The synthesis gas was introduced by bubbling the absorbent 302 using a magnetic stirrer 524 while stirring (1000 rpm). The three-neck wolf bottle 522 was installed in a thermostatic bath 520 maintained at a constant temperature (30 ° C.) using a thermometer 530 and a temperature controller 528. The valve 532 switches the synthesis gas, and thereby, the synthesis gas before scrubbing and the synthesis gas after scrubbing were 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 wet method and dry method, respectively. Details of the measurement method are described in Non-Patent Document 1 and the literature cited therein, and are therefore omitted.

  After scrubbing the synthesis gas, the absorbent 302 and the tar were separated using a centrifuge 526. Specifically, as shown in FIG. 8 (A), 80 mL of absorbent was added to the centrifuge tube, and centrifugation was performed at a rotational speed of 10,000 rpm for 30 minutes. As a result, as schematically shown in FIG. 8B, 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. 8C, it can be seen that tar is deposited at 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. Thereafter, the regeneration of the absorbent 302 and the measurement of the tar concentration of the scrubbed synthesis gas were repeated in the same manner. For comparison, the tar concentration in the synthesis gas was also measured when scrubbing was performed continuously for 10 hours without performing the regeneration operation. The results are shown in FIGS.

FIG. 9 shows experimental results when the absorbent 302 is not regenerated. A curve 550 in FIG. 9 shows the tar concentration measurement result of the synthesis gas not subjected to scrubbing. From this, it can be seen that the synthesis gas contains tar at a concentration of about 30 g / m ³ . A curve 552 is the tar concentration contained in the synthesis gas after scrubbing, and a bar graph shows the tar removal rate, that is, the ratio of tar removed by scrubbing among the tars contained in the synthesis gas. It can be seen from the curve 552 and the bar graph that almost all of the tar is removed immediately after scrubbing. However, it was found that the tar removal rate decreased with time, saturated at about 30% after 7 hours, and the tar removal ability of the absorbent 302 did not change greatly thereafter. When the absorbent 302 was not regenerated, it was confirmed that the amount of tar that can be absorbed by 1 L of the absorbent 302 remains at 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 is the tar concentration contained in the synthesis gas after scrubbing, and the bar graph shows the tar removal rate. Similar to FIG. 9, as shown by a curve 560, it is understood that the synthesis gas contains tar at a constant concentration of about 30 g / m ³ . 100 minutes after the start of scrubbing, the tar removal rate decreased 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 arrow in the figure). Thereafter, regeneration was carried out three times, and it was found that all 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 absorbent 302.

  In this example, the results of evaluating the regeneration of the absorbent 302 by filtration will be described. The evaluation method was the same as in Example 1, and the tar concentration of the scrubbed synthesis gas was monitored for 135 minutes. Thereafter, the absorbent 302 was filtered to remove the tar, and the absorbent 302 was regenerated. For the filtration, the filtration device 450 shown in FIG. 6 was used. Here, in the column 452 (diameter 6.5 cm), two layers each including a second layer 456 (thickness 7 cm) containing polyester and a first layer 454 (thickness 3 cm) containing silica gel in order from the top. Alternatingly stacked. Subsequently, the tar concentration of the synthesis gas scrubbed using the regenerated absorbent 302 was monitored for 135 minutes. Thereafter, the regeneration of the absorbent 302 and the measurement of the tar concentration of the scrubbed synthesis gas were repeated in the same manner. The results are shown in FIG.

As shown by curve 570, it can be seen that the synthesis gas contains tar at a constant concentration of about 30 g / m ³ . Similarly to the results shown in FIG. 9, the tar removal rate decreased to 73% after 100 minutes from the start of scrubbing (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 572 (see arrow in the figure). Thereafter, regeneration was performed three times, and it was found that all showed a tar removal rate comparable to the initial tar removal rate (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 absorbent 302.

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

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

  The results when filtration is performed as a regeneration method are shown in FIGS. In these drawings, the temporal change in the concentration of each component of the light tar in the synthesis gas before purification and in the synthesis gas after scrubbing is shown.

  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 as shown in FIGS. Although a high tar removal rate was shown in the initial stage, it was found that the removal rate hardly recovered even by a regeneration operation every 135 minutes, and that the removal rate gradually decreased with the scrubbing time.

  On the other hand, polycyclic hydrocarbons such as indene and polycyclic aromatic compounds such as naphthalene have higher removal efficiency than benzene, toluene, or phenol. For example, in the case of naphthalene, at least the second regeneration. Previously, it was found to be almost completely removable.

  The results when centrifugation is performed as a regeneration method are shown in FIGS. In the case of benzene, toluene, and phenol, as in regeneration by filtration, as shown in FIGS. 14 (A) to (C), a high tar removal rate is shown at the beginning of scrubbing, but it is also removed by regeneration operation every 135 minutes. The rate did not recover much, and it was found that the removal rate gradually decreased with the scrubbing time.

  On the other hand, it was found that the regeneration effect by centrifugation is great for indene and naphthalene. For example, as shown in FIG. 15 (A), no noticeable decrease in the removal rate of indene was observed between the start of scrubbing and before regeneration, and 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. 15B).

  These results suggest that, among light tar components, tar components having a relatively large molecular weight are effective in removing tar with vegetable oil and regenerating vegetable oil by filtration or centrifugation. Highly volatile substances such as benzene and toluene do not place a heavy burden on equipment such as power generation equipment, but solid or high boiling point substances such as naphthalene and indene can cause equipment blockage. 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 to extend the life of the facilities.

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

A photograph of the microbubbles generated in such an experimental apparatus is shown in FIG. FIG. 17 shows photographs of microbubbles when the bubble generator 308 having R of 0.17, 0.47, and 0.67 is used. Although depending on the flow rate of the absorbent 302 in the throat 324 and the amount of air introduced, it was confirmed that the microbubbles had an average diameter (D _ave ) of about 200 μm to 300 μm.

Here, as shown in FIG. 16, an area of 8 mm × 11 mm in which one side is located at a height of 10 cm from the bottom surface of the tank 304 is observed, and from 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 diameters of the microbubbles were 298 μm, 197 μm, and 263 μm, respectively, when R was 0.17, 0.47, and 0.67.

  Using the apparatus in 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 is a result when bubbling synthesis gas 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 greatly improved by bubbling the synthesis gas as microbubbles using the bubble generator 308. It was also found that the tar removal rate increased as the average diameter of the microbubbles decreased, and that the tar removal rate reached 97.7% when the average diameter was 197 μm. Therefore, as shown in the present embodiment, it can be said that high-efficiency tar removal can be achieved by setting various conditions so that the average diameter of the microbubbles is reduced.

  The embodiments described above as the embodiments of the present invention can be implemented in appropriate combination as long as they do not contradict each other. Based on each embodiment, those in which those skilled in the art appropriately added, deleted, or changed the design of components are also included in the scope of the present invention as long as they have the gist of the present invention.

  Of course, other operational effects that are different from the operational effects provided by the above-described embodiments, which are apparent from the description of the present specification or can be easily predicted by those skilled in the art, are naturally included in the present invention. It is understood that

  100: Step, 102: Step, 104: Step, 106: Step, 200: Gasifier, 202: Hopper, 204: Feeder, 206: Gasifier, 208: Inlet, 210: Discharge conveyor, 212: Unload 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 Axis, 414: supply section, 416: discharge port, 418: scraper, 420: shutter, 422: opening, 424: opening, 430: pump, 432: valve, 450: filtration device, 452: column, 454: first 1 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: Thermostatic bath, 522: Three-neck wolf bottle, 524: Magnetic stirrer, 526: Centrifuge, 528: Temperature adjustment , 530: Thermometer, 532: Valve, 540: sampling unit, 550: curve 552: curve 560: curve 562: curve 570: curve 572: curve 600: power generator

Claims (19)

A gasification furnace that generates combustible gas by heating organic matter;
A scrubber for purifying the combustible gas using an absorbent;
A pyrolysis or gasification system having a regenerator for purifying the absorbent by centrifugation or filtration.   The thermal decomposition or gasification system according to claim 1, further comprising a power generation device that generates electric power using the combustible gas treated by the scrubber.   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 absorbent is vegetable oil.   2. The thermal decomposition or gasification system according to claim 1, wherein the scrubber has a bubble generating device that generates bubbles of the combustible gas in the absorbent. 3.   The pyrolysis or gasification system according to claim 5, wherein the scrubber further includes a tank that holds the absorbent and a pump that circulates the absorbent between the tank and the bubble generating device.   The thermal decomposition or gasification system according to claim 5, wherein the bubble generating device generates the bubbles so that an average diameter of the bubbles is 150 μm or more and 350 μm or less. The bubble generator is
A tube having an inlet and an outlet for the absorbent, and a throat between the inlet and the outlet;
A gas inlet connected to the throat;
The thermal decomposition or gasification system according to claim 5, wherein a cross-sectional area of the inlet and a cross-sectional area of the outlet are larger than a cross-sectional area of the throat. 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 8, wherein a cross-sectional area of the first portion is constant in a direction from the inlet to the second portion.   The thermal decomposition or gasification system according to claim 9, wherein an inner wall of the second portion is inclined with respect to the direction.   The thermal decomposition or gasification system according to claim 10, wherein the inclination of the inner wall is constant in the second portion. The filtration is performed by passing the absorbent through a column in which a plurality of alternating first layers and second layers are stacked,
The first layer comprises a material selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, 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,
A pyrolysis or gasification method comprising regenerating the absorbent used for purification of the combustible gas by centrifugation or filtration.   The thermal decomposition or gasification method according to claim 13, further comprising generating electric power using the purified combustible gas.   The thermal decomposition or gasification method according to claim 13, wherein the regenerated absorbent is circulated and the combustible gas is purified by the regenerated absorbent.   The thermal decomposition or gasification method according to claim 13, wherein the absorbent is vegetable oil.   The thermal decomposition or gasification method according to claim 13, wherein the purification of the absorbent includes generating bubbles of the combustible gas in the absorbent.   The thermal decomposition or gasification method according to claim 17, wherein the bubbles are generated so that an average diameter of the bubbles is 150 μm or more and 350 μm or less. The filtration is performed by passing the absorbent through a column in which a plurality of alternating first layers and second layers are stacked,
The first layer comprises a material selected from activated carbon, diatomaceous earth, silica gel, alumina, magnesium silicate, zeolite,
The thermal decomposition or gasification method according to claim 13, wherein the second layer includes a material selected from polyester, polypropylene, and polyurethane.