Tar removal filter and filter device

Abstract

To reduce cleaning frequency of a turbo of a gas engine and a booster fan more than before by using a filter filling material better in performance of removal of gaseous tar than sawdust to increase power generation efficiency of a biomass power generation system more than before.SOLUTION: A tar removal filter comprises: a flat tube-shaped frame body which has an open upper surface and a lower surface; a filling material with which an inner part of the frame body is filled; an upper wire net which is provided on an open part of the upper surface of the frame body; and a lower wire net which is provided on an open part of the lower surface of the frame body and which has a mesh which is at least finer in size than the filling material. The filling material is one of hydrated lime, activated carbon, or smoked charcoal.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a tar removal filter that removes tar contained in combustible gas generated by heating wood biomass at high temperatures. and Filter Equipment Place Regarding. [Background technology]

[0002] Biomass, a reusable organic energy resource derived from plants and animals, has been attracting attention as a potential contribution to the prevention of global warming through CO2 reduction and the creation of a recycling-oriented society. In recent years, research and development into the effective use of biomass, particularly woody biomass, as energy sources has been actively pursued.

[0003] Examples of woody biomass include waste materials such as thinned wood and sawmill scraps, sawdust from pruning and trimming in parks and botanical gardens, and wood from house demolition. Such woody biomass is a renewable resource and an excellent resource in terms of protecting the global environment. Therefore, the use of woody biomass reduces the use of fossil fuels and at the same time reduces carbon dioxide and curbs global warming.

[0004] An example of a biomass power generation system using woody biomass is a system (direct combustion system) in which woody biomass is directly burned in a boiler or the like, and high-pressure steam generated by the heat of combustion is used to rotate a turbine to generate power.Another example of a biomass power generation system is a system (gasification system) in which combustible gas (fuel gas) generated by thermal decomposition of woody biomass in a gasification furnace is used as fuel to drive an engine to generate power.

[0005] As described above, a direct combustion power generation system is a system that rotates a turbine using high-pressure steam generated by heat generated when woody biomass is burned. For this reason, the direct combustion power generation system has a drawback in that the smaller the overall system, the greater the impact of heat radiation, resulting in poor power generation efficiency. On the other hand, a gasification power generation system can control the power generation output according to the amount of combustible gas generated by thermal decomposition, allowing stable engine operation. Therefore, for example, a gasification power generation system such as an updraft gasifier is more efficient than a direct combustion power generation system, and allows the entire system to be made smaller.

[0006] In the above-mentioned gasification power generation system, the combustible gas generated by the thermal decomposition of woody biomass contains tar, which is a high molecular weight hydrocarbon. Tar is gaseous at high temperatures, but has the property of coagulating at low temperatures. Therefore, the tar contained in the combustible gas adheres to the inside of the piping, the fan, etc., during the process of being fed into the gas engine. For example, if there is a large amount of tar adhesion, the rotation of the fan may stop, so the generation of tar reduces the power generation performance of the entire power generation system. Furthermore, in a gasification power generation system (gasification power generation equipment), the tar in the combustible gas (generated gas) also has a negative effect on stable operation. In particular, when cleaning the booster fan or the gas engine, the power generation output is suppressed due to the shutdown of the equipment, so if the cleaning frequency is high, the desired power generation amount cannot be obtained.

[0007] Therefore, for example, in gasification power generation systems, in addition to gas coolers and wet electrostatic precipitators, HEPA filters (High Efficiency Particulate Air Filters) are used to remove tar contained in exhaust gases and flammable gases (see, for example, Patent Document 1).

[0008] The applicant also developed a sawdust filter filled with sawdust, and by using this sawdust filter, the applicant succeeded in significantly reducing the cleaning frequency of the booster fan. Furthermore, when the applicant used a sawdust filter filled with sawdust, a significant change was observed that reduced the cleaning frequency of the turbocharger of the gas engine (see, for example, Figure 10). Note that sawdust means sawdust. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2001-90510 A Summary of the Invention [Problem to be solved by the invention]

[0010] However, there is a demand to further reduce the frequency of cleaning, avoid equipment downtime, and increase the power generation efficiency in biomass power generation systems.

[0011] Therefore, the present disclosure aims to reduce the frequency of cleaning the turbo and booster fan of a gas engine and improve the power generation efficiency of a biomass power generation system by using a filter filler that has better gaseous tar removal performance than sawdust. [Means for solving the problem]

[0012] A tar removal filter according to one embodiment includes a flat cylindrical frame having an open upper and lower surface, a filler packed inside the frame, an upper wire mesh provided in the open portion of the upper surface of the frame, and a lower wire mesh provided in the open portion of the lower surface of the frame and having a mesh size finer than the size of the filler. The filler is made of slaked lime. ,also Hakun With charcoal It is characterized by the fact that

[0013] In the tar removal filter according to one embodiment, the filler may be removed from the wire mesh after the tar contained in the gas adheres to and solidifies, and then may be thrown into a gasification furnace together with wood chips.

[0014] A filter device according to one embodiment comprises a flat cylindrical frame body with open top and bottom surfaces, a filler packed inside the frame body, a tar removal filter having an upper wire mesh provided at the opening part of the top surface of the frame body, and a lower wire mesh provided at the opening part of the bottom surface of the frame body and having a mesh size at least finer than the size of the filler material, and a filter mounting frame in which the tar removal filter is removably held and which has a plurality of shelves arranged parallel to the gas flow direction and at predetermined intervals, and a straightening plate which separates two adjacent shelves at an angle with respect to the gas flow direction, and the filler material is any one of slaked lime, activated carbon, or smoked charcoal.

[0015] In addition, in one embodiment of the filter device, the device body may further include a filter mounting frame therein, and the shelves may be arranged in a vertical direction at a predetermined interval, and the baffle plate may be disposed between two adjacent upper and lower shelves and incline downward toward the downstream side of the gas sent into the device body to separate the two adjacent upper and lower shelves.

[0016] In addition, in the filter device according to one embodiment, the filler may be removed from the wire mesh after the tar contained in the gas adheres to and solidifies, and then may be thrown into a gasification furnace together with wood chips. Effect of the Invention

[0023] According to the present disclosure, by using a filter filler that has better gaseous tar removal performance than sawdust, it is possible to reduce the frequency of cleaning the turbo and booster fan of a gas engine compared to conventional methods, and to improve the power generation efficiency of a biomass power generation system compared to conventional methods. [Brief description of the drawings]

[0024] [Figure 1]FIG. 1 is a diagram illustrating an embodiment of a gasification power generation system, which is one of biomass power generation systems. [Diagram 2] FIG. 2 is a diagram illustrating an example of a filter device illustrated in FIG. [Diagram 3] FIG. 3 is a diagram showing an example of the tar removal filter shown in FIG. 2. [Figure 4] FIG. 4 is a diagram showing an outline of a performance test of a filler to be filled in the tar removal filter shown in FIGS. 1 to 3. [Diagram 5] FIG. 5 is a diagram showing an outline of the filler used in the performance test shown in FIG. 4. [Figure 6] FIG. 5 is a diagram showing the results of the performance test shown in FIG. [Figure 7] FIG. 6 is a diagram showing the state of the packing material (tray) shown in FIG. 5 before and after testing. [Figure 8] FIG. 13 is a diagram showing an outline of performance confirmation in a comparative example in which sawdust is used as a filler to be filled in a tar removal filter. [Figure 9] FIG. 9 is a diagram showing the results (1) of the performance confirmation shown in FIG. [Figure 10] FIG. 9 is a diagram showing the results (2) of the performance confirmation shown in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, embodiments of the tar removal filter, the filter device, and the biomass power generation system disclosed herein will be described with reference to the drawings.

[0026] <One embodiment> FIG. 1 is a diagram that illustrates a schematic diagram of an embodiment of a gasification power generation system (hereinafter, referred to as a "gasification power generation system") 1, which is one of biomass power generation systems.

[0027] As shown in Fig. 1, the gasification power generation system 1 of this embodiment is a system that generates combustible gas (fuel gas) 24 by heating woody biomass fed into a gasification furnace 12 to a high temperature, and generates power by driving a gas engine 18 using the generated combustible gas 24 as fuel. Note that the woody biomass fed into the gasification furnace 12 may be wood chips 21 (including pellets). The wood chips 21 are produced by crushing thinned wood, scraps and waste wood after sawing, wood chips generated by pruning and trimming from parks and botanical gardens, wood from house demolition work, etc., in a crushing building (not shown).

[0028] 1, the gasification power generation system 1 includes a hopper 11, a gasification furnace 12, a product gas cooler 13, and a wet electrostatic precipitator 14. The gasification power generation system 1 also includes a filter device 15, a booster fan 16, a HEPA filter 17, a gas engine 18, a heat exchanger 19, and an exhaust tower 20.

[0029] The hopper 11 is a device that stores wood chips 21 to be fed into the gasification furnace 12. The wood chips 21 stored inside the hopper 11 are transported toward the gasification furnace 12 by a conveyor device 11a and fed into the gasification furnace 12 from above the gasification furnace 12.

[0030] The gasifier 12 is maintained in such a way that the temperature inside the furnace (in other words, the gasification temperature) is within a predetermined temperature range. The gasifier 12 may have a furnace type such as a fixed bed, a moving bed, a fluidized bed, or an entrained bed, or a heating method such as direct heating (direct gasification method) or indirect heating (indirect gasification method). Therefore, the gasifier 12 used may have a combination of furnace type and heating method based on the conditions of use.

[0031] The gasification furnace 12 receives wood chips 21 from above, while sending a gasifying agent 23 into the furnace from an inlet provided at the bottom. The gasifying agent 23 is, for example, a mixture of air, oxygen, steam, etc. The gasifying agent 23 is sent to the gasification furnace 12 after being preheated with hot water 28.

[0032] In the gasification furnace 12, wood chips 21 fed from the top of the furnace and gasifying agent 23 fed from the bottom of the furnace undergo a thermal reaction (pyrolysis) to generate combustible gases (carbon monoxide, carbon dioxide, hydrogen, methane, etc.) 24 and char (ash). The combustible gas 24 generated inside the gasification furnace 12 is accompanied by a large amount of tar and carbon particles. This combustible gas 24 is sent from the top of the gasification furnace 12 to the generated gas cooler 13.

[0033] The produced gas cooler 13 cools the combustible gas 24 sent out from the gasification furnace 12 using two produced gas coolers 13a, 13b. In the process of cooling the combustible gas 24, moisture and tar 25 (wood tar and wood vinegar) are removed from the combustible gas 24. Here, the temperature of the combustible gas 24 sent out from the gasification furnace 12 to the produced gas cooler 13 is, for example, 75°C. In the first produced gas cooler 13a included in the produced gas cooler 13, the combustible gas 24 is cooled to, for example, 55°C, and in the second produced gas cooler 13b, it is further cooled to, for example, 35°C.

[0034] The wet electrostatic precipitator 14 is a device that collects tar 25 and moisture remaining in the combustible gas 24 cooled in the product gas cooler 13 .

[0035] The filter device 15 removes tar 25 contained in the flammable gas 24. The filter device 15 will be described in detail later.

[0036] The booster fan 16 (hereinafter also referred to as "fan 16") draws in the combustible gas 24 from the wet electrostatic precipitator 14 and sends it out towards the HEPA filter 17. The combustible gas 24 sent out to the rear stage by the fan 16 is pressurized in the process of being sent out by the fan 16. As a result, the temperature of the combustible gas 24 drawn in from the wet electrostatic precipitator 14 by the fan 16 is, for example, 35°C, but the temperature of the combustible gas 24 sent out from the fan 16 is heated to, for example, 65°C by the pressurization by the fan 16.

[0037] The HEPA filter 17 is a type of air filter used for the purpose of removing dirt, dust, etc. from the air to make the air clean. The HEPA filter 17 is mainly made of glass fibers having a diameter of 1 to 10 μm or less. Here, the HEPA filter 17 is generally vulnerable to water, and therefore cannot be arranged upstream of the fan 16 where the temperature of the flammable gas 24 is low. On the other hand, downstream of the fan 16, the temperature of the flammable gas 24 is, for example, 65° C. due to the adiabatic compression effect, so the temperature of the flammable gas 24 is higher and the relative humidity is lower than that upstream of the fan 16, and therefore the HEPA filter 17 can be arranged there. For this reason, in this embodiment, the filter device 15 is arranged upstream of the fan 16, and the HEPA filter 17 is arranged downstream of the fan 16.

[0038] The gas engine 18 is a device that generates electricity by being driven by the combustible gas 24 from which tar 25 has been removed by the filter device 15 and the HEPA filter 17 as fuel.

[0039] The heat exchanger 19 is a device that exchanges heat between exhaust gas 27 from the gas engine 18 and circulated hot water 28.

[0040] The exhaust stack 20 is a chimney that discharges exhaust gases 27 from the gas engine 18 .

[0041] The combustible gas 24 is a gas generated in the gasification furnace 12 using wood chips 21, which are an example of wood biomass, and a gasifying agent 23. Here, the combustible gas 24 flows as shown by the arrows labeled with the symbol 24 in FIG. 1. The combustible gas 24 is hot immediately after generation and contains a large amount of tar 25 and moisture. The combustible gas 24 is cooled by passing through the generated gas cooler 13 and the wet electrostatic precipitator 14, and tar-containing water 26 containing tar 25 and moisture is removed. The combustible gas 24 sent out from the wet electrostatic precipitator 14 passes through the filter device 15 and reaches the HEPA filter 17 in a pressurized state by the fan 16. When the combustible gas 24 passes through the filter device 15 and the HEPA filter 17, the tar 25 is removed. The combustible gas 24 that has passed through the filter device 15 and the HEPA filter 17 becomes a clean gas and is sent to the gas engine 18.

[0042] Tar 25 contains hydrocarbons, phenols, acetic acid, etc., and is a viscous, black to brown, oily liquid obtained by the thermal decomposition of organic substances.

[0043] The tar-containing water 26 is mainly composed of moisture contained in the wood chips 21, humidified water supplied for steam reforming, and tar 25. The tar-containing water 26 is obtained by condensing the moisture contained in the wood chips 21 and the steam not used for steam reforming in the generated gas cooler 13 and the wet electrostatic precipitator 14, separating it from the combustible gas 24, and discharging it together with the tar 25. The discharged tar-containing water 26 is gravity separated into heavy tar and light tar, and the heavy tar is burned and incinerated by a heavy tar burner of a tar combustion device (not shown), and the light tar is heat exchanged or the like and then burned and incinerated in a tar combustion device (not shown).

[0044] The exhaust gas 27 is exhausted from the gas engine 18. The exhaust gas 27 is subjected to heat exchange by the heat exchanger 19 and then exhausted from the exhaust tower 20.

[0045] The hot water 28 has been subjected to heat exchange with the exhaust gas 27 from the gas engine 18, and is utilized as the residual heat of the gasifying agent 23 used in the gasification furnace 12, the residual heat of the air in a tar combustion device (not shown), etc.

[0046] Next, the filter device 15 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the filter device 15 shown in Fig. 1.

[0047] As shown in FIG. 2, the filter device 15 includes a device body 31, a filter installation frame 33, a door , and a plurality of tar removal filters .

[0048] The device body 31 is, for example, rectangular, and has an inlet 36 through which the flammable gas 24 flows in and an outlet 37 through which the flammable gas 24 is sent out on the upper surface. Here, since tar 25 accumulates in the lower portion of the device body 31 of the filter device 15, if the inlet 36 and the outlet 37 are provided on the lower surface, the tar 25 will flow down the inlet 36 and the outlet 37, and maintenance of the equipment below will be required. For this reason, the inlet 36 and the outlet 37 are provided on the upper portion of the device body 31. However, the positions at which the inlet 36 and the outlet 37 are provided do not need to be limited to the upper portion of the device body 31, as long as they are not affected by the tar 25 that accumulates on the lower portion. In addition, the device body 31 has a filter installation frame 33 in which multiple tar removal filters 35 are installed, and has work spaces on the upstream and downstream sides of the filter installation frame 33 for cleaning the inside of the device body 31 or replacing the multiple tar removal filters 35.

[0049] The filter installation frame 33 is installed in the area between the inlet 36 and the outlet 37 inside the device body 31. That is, the above-mentioned working space is provided below the inlet 36 or the outlet 37 inside the device body 31. This working space becomes a space through which the combustible gas 24 flows during the process of removing tar 25 from the combustible gas 24 by the filter device 15. By providing this space, the combustible gas 24 flowing into the device body 31 is evenly distributed to the tar removal filter 35 held on the shelf 41 of the filter installation frame 33. Note that the device body 31 may have a configuration in which the working space is omitted and the combustible gas 24 flowing in from the inlet 36 is directly guided to the tar removal filter 35 held on the shelf 41 of the filter installation frame 33.

[0050] The filter mounting frame 33 holds a plurality of tar removal filters 35 at predetermined intervals in the vertical direction. In this embodiment, six stages of the tar removal filters 35 are held in the filter mounting frame. The filter mounting frame 33 has an upper surface and left and right side surfaces in the figure that are open. The filter mounting frame 33 has a plurality of shelves 41 and a baffle plate 42 that is arranged between the upper and lower two shelves 41.

[0051] The shelves 41 detachably hold the tar removal filters 35. That is, the tar removal filters 35 held on the respective shelves 41 are replaceable.

[0052] The straightening plate 42 is a plate material that slopes downward from the front side (left end in FIG. 2) of the upper shelf 41 of the two upper and lower shelves 41 to the rear side (right end in FIG. 2) of the lower shelf 41. Therefore, when the tar removal filter 35 is installed on each shelf 41 of the filter installation frame 33, the flammable gas 24 flowing in from the inlet 36 of the device body 31 is straightened by each straightening plate 42 of the filter installation frame 33. As a result, the flammable gas 24 passes from top to bottom through the tar removal filter 35 held on the shelf 41. In the process, the tar 25 contained in the flammable gas 24 is removed. The width, height, and depth of the filter installation frame 33 are, for example, width x height x depth = 610 mm x 610 mm x 300 mm. The weight of the filter installation frame 33 is, for example, about 35 kg.

[0053] The door 34 is opened and closed when an operator cleans the inside of the apparatus main body 31 or replaces the multiple tar removal filters 35.

[0054] Next, the configuration of the tar removal filter 35 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the tar removal filter 35 shown in Fig. 2.

[0055] 3, the tar removal filter 35 has a rectangular parallelepiped shape (tray shape) that is flat in the horizontal direction. Note that the shape of the tar removal filter 35 is not limited to a rectangular parallelepiped shape, and may be other shapes depending on the condition of the installation location as long as the shape is flat in the horizontal direction.

[0056] The tar removal filter 35 has a frame 51, an upper wire mesh 52, a lower wire mesh 53, and a filler 54.

[0057] The frame 51 has a frame shape (flat cylinder shape) with the top and bottom open. The width, height, and depth of the frame 51 are, for example, width×height×depth=610 mm×40 mm×300 mm. The frame 51 has a gripping portion 52a on one side. The gripping portion 52a is gripped when the tar removal filter 35 is pulled out from the shelf 41.

[0058] Upper wire mesh 52 is disposed in the opening portion on the top surface of frame body 51. Upper wire mesh 52 is a crimped wire mesh with a mesh size of, for example, 10 mm × 10 mm. Upper wire mesh 52 may have one end pivotally supported horizontally relative to frame body 51 and the other end held so as to be openable and closable in the vertical direction, or may be detachable from frame body 51.

[0059] The lower wire mesh 53 is disposed in the opening portion of the lower surface of the frame body 51. The lower wire mesh 53 has a crimped wire mesh 53a having a mesh size of, for example, 20 mm x 20 mm, and a 20-mesh wire mesh 53b. The material of the 20-mesh wire mesh 53b is, for example, stainless steel. The lower wire mesh 53 is disposed in the opening portion of the lower surface of the frame body 51, for example, in a state in which the crimped wire mesh 53a and the wire mesh 53b are layered in this order from below. The lower wire mesh 53 may be integrally molded with the frame body 51, or may be detachable from the frame body 51.

[0060] As described below, the filler 54 is made of limestone 61, slaked lime 62, activated carbon 63, and smoked charcoal 64. The filler 54 is packed evenly inside the frame 51 holding the lower wire mesh 53. The height of the filler 54 packed inside the frame 51 is, for example, 40 mm, which is the height of the frame 51, or less. Conventionally, when sawdust 65 was used as the filler 54, the height of the frame 51 was 20 mm. This time, by setting the height of the frame 51 to 40 mm, more filler 54 can be packed than when the height of the frame 51 is 20 mm, and therefore more gaseous tar 25 can be removed.

[0061] As described above, the lower wire net 53 is a wire net 53b of 20 mesh laminated on the upper side of the crimped wire net 53a. On the other hand, the filler 54 is, for example, about 2 mm square or larger, which is the size of the part left on a 10-mesh sieve. In general, the mesh (opening) of a 20-mesh wire net is about 1 mm x 1 mm at most, so the filler 54 packed inside the frame 51 is larger than the mesh of the lower wire net 53 and will not fall from the lower wire net 53. Note that, since the size of the filler 54 is at least larger than the mesh size of the lower wire net 53, if the size of the filler 54 is obviously larger than the mesh size of the lower wire net 53, the filler 54 does not need to be sieved before filling. In addition, the lower wire net 53 is not limited to a laminate of two wire nets, and may be a single wire net or a laminate of three or more wire nets.

[0062] The tar removal filter 35 thus configured is in the shape of a flat tray. Therefore, the area of ​​contact with the flammable gas 24 passing through the filter device 15 is sufficiently secured. In addition, by using the above-mentioned filler 54 as the tar removal filter 35, the tar contained in the flammable gas 24 adheres to the filler 54 when passing through the tar removal filter 35, and the tar 25 is removed from the flammable gas 24 after passing through the filter. Note that by making the tar removal filter 35 in the shape of a flat tray, pressure loss can be suppressed even if the tar 25 adheres to the filler 54.

[0063] <Performance test> Next, a performance test using the tar removal filter 35 of this embodiment will be described.

[0064] Fig. 4 is a diagram showing an outline of a performance test of the filler 54 filled in the tar removal filter 35 shown in Fig. 1 to Fig. 3. In the following description of the performance test, the same components as those shown in Fig. 1 to Fig. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0065] The applicant conducted a performance test of the filler 54 using the filter device 15 shown in Fig. 2. The filter device 15 used in the performance test has the same configuration as that shown in Fig. 2, and has six shelves 41. A tar removal filter 35 was arranged on each shelf 41, resulting in six shelves of tar removal filters 35. The tar removal filter 35 used in the performance test has the same configuration as that shown in Fig. 3, and an upper wire mesh 52 and a lower wire mesh 53 are arranged on a frame 51 having a width x height x depth of 610 mm x 40 mm x 300 mm. That is, the height of the frame 51 is 40 mm, and the volume in which the filler 54 can be packed is approximately 43.2 L.

[0066] In the performance test, the filler 54 was filled into each of the six stages of the tar removal filter 35 shown in Fig. 4, and the concentration of gaseous tar 25 (also referred to as "gaseous tar 25") at the inlet and the concentration of gaseous tar 25 at the outlet were measured. Then, for each filler 54, the percentage of gaseous tar removed was measured from the difference between the concentration of gaseous tar 25 at the inlet and the concentration of gaseous tar 25 at the outlet. The measurements were performed 2 hours, 5 hours, and 24 hours after filling with the filler 54.

[0067] Fig. 5 is a diagram showing an outline of the filler 54 used in the performance test shown in Fig. 4. In the performance test, limestone 61, slaked lime 62, activated carbon 63, and charcoal 64 were used as the filler 54. Note that sawdust 65 (not shown) was also used as a comparative example.

[0068] Limestone 61 is the name of mineral calcite or aragonite, or rock limestone or crystalline limestone (marble), when it is treated as a resource. Limestone 61 is a calcium carbonate salt represented by calcium carbonate CaCO3. According to FIG. 5, the particle size of limestone 61 is 5 to 13 mm, and the amount required for one use, in other words, the amount required for one filling of one filter device 15, is 56 kg, and the reference price for the amount required for one use is 3,100 yen.

[0069] Slaked lime 62 was originally made from limestone, which was crushed and burned in a furnace, then hydrated and aged. Slaked lime 62 is a calcium hydroxide expressed as calcium hydroxide Ca(OH)2. According to Figure 5, the grain size of slaked lime 62 is 2-5 mm, the amount required for one use is 43 kg, and the reference price for one required amount is 1,500 yen.

[0070] Activated carbon 63 is a substance whose main component is porous carbon that has been subjected to chemical or physical treatment (activation, activation) to increase its adsorption efficiency. Activated carbon 63 is a porous substance that is mostly carbon, as well as oxygen, hydrogen, calcium, etc., and because it is porous, it has a large surface area compared to its volume, so it has the property of adsorbing many substances. For this reason, activated carbon 63 is used for deodorization, water purification, and the adsorption and removal of harmful substances. According to Figure 5, activated carbon 63 has a particle size of 8 mm, the amount needed for one use is 22 kg, and the reference price for the amount needed for one use was 28,000 yen.

[0071] Smoked charcoal 64 is made by steaming and carbonizing rice husks and wood chips. It is porous and breathable, and is used as a soil conditioner. Smoked charcoal 64 can be produced at low cost because it uses rice husks that are produced when rice is polished and would otherwise be discarded. Smoked charcoal 64 is often sold at agricultural cooperatives, home improvement stores, and stores that handle agricultural supplies. Rice husks (rice husks) are the outermost skin of rice grains (hulled rice). According to Figure 5, smoked charcoal 64 has a particle size of 1.7 mm or more, the amount needed for one use is 4 kg, and the reference price for the amount needed for one use is 1,200 yen.

[0072] The sawdust 65, not shown, is generated when wood chips 21 are manufactured from wood such as thinned wood in a chip crushing building, not shown. The sawdust 65 is known to have the property of adsorbing hydrocarbons contained in tar 25, such as naphthalene and phenanthrene. For example, sawdust 65 having a size of about 2 mm square that is left after passing through a 10-mesh sieve is used. Since the sawdust 65 is essentially waste generated during the manufacture of the wood chips 21, no cost is incurred for the sawdust 65.

[0073] Fig. 6 is a diagram showing the results of the performance test shown in Fig. 4. Fig. 6 shows the removal ratio of gaseous tar 25 of the fillers 54 shown in Fig. 5 and sawdust 65 (not shown) after two hours. In Fig. 6, the vertical axis shows the removal ratio of gaseous tar 25, and the horizontal axis shows each filler. Fig. 6 shows the removal ratio of each filler 54 when the amount of gaseous tar 25 removed from sawdust 65 after two hours has elapsed since each filler 54 shown in Fig. 5 was filled is set to 1.

[0074] As shown in FIG. 6, if the amount of gaseous tar 25 removed by sawdust 65 after two hours is set to 1, limestone 61 also has a value of 1, and the amount of gaseous tar 25 removed was almost the same as that of sawdust 65. On the other hand, slaked lime 62 had a value of about 1.5, which means that as a filler 54, it performed 1.5 times better than sawdust 65. Activated carbon 63, which is generally considered to have a good removal rate, had a value of about 1.9, which means that as a filler 54, it performed about twice better than sawdust 65. Smoked charcoal 64 had a value of about 3.3, which means that as a filler 54, it performed more than three times better than sawdust 65, and it performed remarkably well among the fillers 54 used in the performance test.

[0075] Fig. 7 is a diagram showing the state of the filler (tray) shown in Fig. 5 before and after the test. From the left in Fig. 7, the states of limestone 61, slaked lime 62, activated carbon 63, and charcoal 64 before and after the test are shown, with the upper row showing the state of the filler 54 before the test. The middle row shows the state of the tray after the test (the upper surface of the lower wire mesh 53 of the tar removal filter 35 after the upper wire mesh 52 has been removed and the filler 54 has been removed), and the lower row shows the pressure loss (and the pressure loss after 24 hours). Note that sawdust 65 used as a comparative example is not shown.

[0076] As shown in Fig. 7, the tray of the tar removal filter 35 using limestone 61 as the filler 54 was considerably dirty after the test. This is thought to be because, although limestone 61 has the same removal performance of sawdust 65 and gaseous tar 25 as other fillers 54, limestone 61 removed less gaseous and particulate tar 25 than other fillers 54, as shown in Fig. 6. As a result, it is thought that tar 25 stuck to the tray frame 51 and lower wire mesh 53, as shown in Fig. 7. The pressure loss of limestone 61 was 130 to 150 Pa, and was 150 Pa even after 24 hours, so the pressure loss was almost unchanged.

[0077] In the tar removal filter 35 using slaked lime 62 as the filler 54, the tray is relatively clean after the test, but the edges are dirty. This is thought to be because the slaked lime 62 removes the gaseous and particulate tar 25, but the tar 25 is not completely removed and adheres to the edges of the tray frame 51 and the lower wire mesh 53. However, the pressure loss of the slaked lime 62 is 310 to 330 Pa, but after 24 hours, it becomes 2210 Pa, which is a very high pressure loss. Here, the slaked lime 62 is alkaline, but the components of the tar 25 are contained in the liquid particles contained in the gas after gasification of the woody biomass together with acid components such as acetic acid. The principle of removing the tar 25 contained in the liquid particles is expected to be a chemical neutralization reaction between the alkaline slaked lime 62 and the acidic liquid particles, so the increased pressure loss is thought to be due to the slaked lime 62 dissolving due to the neutralization reaction and the fillers 54 sticking to each other.

[0078] In the tar removal filter 35 using activated carbon 63 as the filler 54, the tray was quite clean after the test. This is thought to be because the activated carbon 63 removed a significant amount of gaseous and particulate tar 25, and almost no tar 25 adhered to the tray frame 51 or the lower metal mesh 53. The pressure loss of the activated carbon 63 was 190 to 200 Pa, and even after 24 hours it was 200 Pa, so the pressure loss was almost unchanged.

[0079] In the tar removal filter 35 using charcoal 64 as the filler 54, the tray was quite clean after the test. This is thought to be because the charcoal 64 removed a significant amount of gaseous and particulate tar 25, and almost no tar 25 adhered to the tray frame 51 or the lower wire mesh 53. The pressure loss of the charcoal 64 was 290 to 310 Pa, and after 24 hours it was 330 Pa, so although the pressure loss value was slightly higher, there was no significant difference.

[0080] According to the results of the performance test by the applicant described above, in the results of the removal ratio of gaseous tar 25 shown in FIG. 6, when charcoal 64 was packed as the packing material 54, the results were remarkably the best compared to when other packing materials 54 were packed. Moreover, according to the table shown in FIG. 5, charcoal 64 is the lightest and cheapest packing material 54. Moreover, according to the table shown in FIG. 7, there was almost no dirt on the tray and the pressure loss was almost the same. For this reason, it was found that charcoal 64 is the most excellent packing material 54 in the filter device 15 having the tar removal filter 35 of this embodiment.

[0081] In addition, in the results of the removal ratio of gaseous tar 25 shown in FIG. 6, when activated carbon 63 is packed as the packing material 54, the results are better than those of other packing materials 54, although they are not as good as those of charcoal 64. In addition, as shown in the table in FIG. 5, activated carbon 63 is a relatively lightweight packing material 54, although it is expensive. In addition, as shown in the table in FIG. 7, there is almost no dirt on the tray, and the pressure loss is almost the same. Therefore, it was found that in the filter device 15 having the tar removal filter 35 of this embodiment, activated carbon 63 can be sufficiently used as the packing material 54, although it has the drawback of being expensive and not as good as charcoal 64 in performance.

[0082] In addition, in the results of the removal ratio of gaseous tar 25 shown in FIG. 6, when slaked lime 62 is filled as the filler 54, the results are better than those of sawdust 65 and limestone 61. In addition, as shown in the table in FIG. 5, slaked lime 62 is slightly heavy, but is inexpensive. In addition, as shown in the table in FIG. 7, the edges of the tray are only soiled. However, the pressure loss after 24 hours is a very high value. For this reason, it was found that in the filter device 15 having the tar removal filter 35 of this embodiment, although it is slightly heavy and has problems with pressure loss, slaked lime 62 can be used sufficiently as the filler 54 in terms of performance.

[0083] On the other hand, in the results of the removal ratio of gaseous tar 25 shown in FIG. 6, when limestone 61 was filled as the filler 54, the results were almost the same as those when sawdust 65 was filled. Also, as shown in the table in FIG. 5, limestone 61 is slightly expensive and heavy. Also, as shown in the table in FIG. 7, although the pressure loss is almost the same, the tray is quite dirty. For this reason, it was found that it is difficult to use limestone 61 instead of sawdust 65 as the filler 54 in the filter device 15 having the tar removal filter 35 of this embodiment.

[0084] <When using sawdust> Next, as a comparative example, a performance check will be described for a case where sawdust is used as the filler 54 of a tar removal filter.

[0085] 8 is a diagram showing an outline of a comparative example of performance confirmation in which sawdust 65 is used as the filler 54 filled in the tar removal filter 35'. In the following description of the performance test, the same components as those shown in Figs. 1 to 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0086] The applicant used a filter device 15' shown in Fig. 8 to confirm the performance when sawdust 65 was used as the filler 54. As described above, the sawdust 65 generated during the production of wood chips 21 has the property of adsorbing tar 25, so the applicant used sawdust 65 as the filler 54 to confirm the performance. As shown in Fig. 8, the gas containing tar 25 passes through the sawdust 65 and flows to the subsequent stage, so that the tar 25 is adsorbed and removed by the sawdust 65.

[0087] In the filter device 15' shown in Fig. 8, the height of the frame 51 in the tar removal filter 35' is 20 mm. The filter device 15' has seven shelves 41. A tar removal filter 35' is disposed on each shelf 41, resulting in seven shelves of tar removal filters 35'. The tar removal filter 35' used for the performance verification shown in Fig. 8 has an upper wire mesh 52 and a lower wire mesh 53 disposed on a frame 51 having a width x height x depth = 610 mm x 20 mm x 300 mm.

[0088] The applicant installed a filter device 15' shown in Figure 8 at the position indicated by 15 in the gasification power generation system 1 shown in Figure 1, operated the gasification power generation system 1, and confirmed its performance as a tar removal filter 35', as well as changes in cleaning frequency and power generation.

[0089] Fig. 9 is a diagram showing the result (1) of the performance confirmation shown in Fig. 8. Fig. 9 shows the result of confirming the performance of the tar removal filter 35' when sawdust 65 is used as the filler 54.

[0090] 9, from the left, the tar adhesion state, color difference (ΔE), amount of tar adhesion (g-tar / g-sawdust), and pressure loss (Pa) of sawdust 65 are shown before use, after 2 days, and after 4 days, from the top. Note that color difference ΔE is the distance between two points on the color space (the difference between a sample specimen and a blank sheet of paper), and for reference, the pressure loss of a HEPA filter is 270 Pa. In the following descriptions, some units are omitted.

[0091] The sawdust 65 before use had a beautiful wood color without any tar 25. The color difference of the sawdust 65 before use was 61, and the pressure loss was 120.

[0092] The sawdust 65 after two days was dark brown due to the adhesion of a small amount of tar 25. The color difference of the sawdust 65 after two days was 76, the amount of tar adhesion was 0.47g-tar / g-sawdust, and the pressure loss was 120.

[0093] The sawdust 65 after 4 days had turned black due to the adhesion of a large amount of tar 25. The color difference of the sawdust 65 after 4 days was 84, the amount of tar adhesion was 0.91 g-tar / g-sawdust, and the pressure loss was 130.

[0094] From the above performance verification results, it was confirmed that the color difference and amount of tar adsorption increased as the days passed, and that tar adsorption was confirmed. In addition, it was confirmed that the pressure loss was stable at 120-130 Pa, which is lower than the HEPA filter, while the initial pressure loss of the HEPA filter was 270 Pa. From these results, it was found that the tar removal filter 35' using sawdust 65 as the filler 54 can remove tar 25, and is superior to the HEPA filter in terms of pressure loss.

[0095] Fig. 10 is a diagram showing the results (2) of the performance verification shown in Fig. 8. The left side of Fig. 10 shows the cleaning frequency (upper row) and the power generation amount (lower row) before the filter device 15' shown in Fig. 8 is installed at the position indicated by 15 in the gasification power generation system 1 shown in Fig. 1. The right side of Fig. 10 shows the cleaning frequency (upper row) and the power generation amount (lower row) after the filter device 15' shown in Fig. 8 is installed at the position indicated by 15 in the gasification power generation system 1 shown in Fig. 1.

[0096] In the table in the upper part of FIG. 10, the days on which the tar 25 was cleaned are indicated by circles. On the left side, which shows the cleaning frequency before the installation of the filter device 15', the gas engine 18 was cleaned every week, and the booster fan 16 was cleaned once every four weeks. On the other hand, on the right side, which shows the cleaning frequency after the installation of the filter device 15', the gas engine 18 was cleaned approximately once every two weeks, and the booster fan 16 was cleaned approximately once every 12 weeks. Therefore, it was confirmed that the installation of the filter device 15' in which the tar removal filter 35' using sawdust 65 as the filler 54 was arranged reduced the cleaning frequency of both the gas engine 18 and the booster fan 16.

[0097] The graph in the lower part of FIG. 10 shows the amount of power generated in one day. The vertical axis indicates the amount of power generated per day, and the horizontal axis indicates the date. The higher the graph, the more power generated on that day. For example, the maximum value in the graph indicates that the gasification power generation system 1 was fully operational and generated the maximum amount of power. In other words, the larger the area occupied by the graph, the more power generated. The more power generated, the more income there is, so improving power generation efficiency is an important issue for the plant. In this regard, it was confirmed that the installation of the filter device 15' in which the tar removal filter 35' using sawdust 65 as the filler 54 was arranged reduced the frequency of cleaning the gasification power generation system 1 and extended the time of full operation, thereby increasing the amount of power generated. The reason why the amount of power generated near the center of both the left and right graphs in the lower part is low is because the gasification power generation system 1 was stopped for several days due to maintenance of equipment unrelated to the present invention.

[0098] <Effects of one embodiment> As described above, according to the embodiment shown in Figures 1 to 7, by using slaked lime 62, activated carbon 63, or charcoal 64 as the filler 54 of the tar removal filter 35, it is possible to remove more gaseous tar 25 than if these are not used.

[0099] 8 to 10, it was found that by using the tar removal filter 35' using sawdust 65 as the filler 54, it was possible to remove more tar 25 than when not using the tar removal filter 35'. It was also found that this reduces the frequency of cleaning the gasification power generation system 1 and increases the amount of power generation.

[0100] On the other hand, from the results of the performance tests shown in Figures 4 to 7, it was found that the slaked lime 62, activated carbon 63, and charcoal 64 used as the filler 54 in the embodiment described in Figures 1 to 7 have better performance in removing gaseous tar 25 than sawdust 65. For this reason, if slaked lime 62, activated carbon 63, or charcoal 64 is used instead of sawdust 65 as the filler 54 of the tar removal filter 35, it is possible to remove gaseous tar 25 more effectively than the results shown in Figures 8 to 10 above.

[0101] 1 to 7, by using the filter filler 54 having better performance of removing gaseous tar 25 than sawdust 65, the cleaning frequency of the turbo and booster fan 16 of the gas engine 18 can be reduced compared to the conventional method. This makes it possible to improve the power generation efficiency in the gasification power generation system 1 compared to the conventional method. In other words, if slaked lime 62, activated carbon 63, or smoked charcoal 64 is used as the filler 54 of the tar removal filter 35, the cleaning frequency of the gasification power generation system 1 can be reduced compared to when sawdust 65 is used as the filler 54, and the power generation efficiency can be improved.

[0102] <Supplementary information for the embodiment> 1 to 7, the filter device 15 is provided upstream of the fan 16. However, a filter device 15 may also be provided downstream of the fan 16 in place of the HEPA filter 17 or in combination with the HEPA filter 17. Also, a plurality of filter devices 15 may be provided in series or in parallel. This further reduces the frequency of maintenance such as cleaning of the fan 16, the HEPA filter 17, and the gas engine 18, and further improves power generation efficiency.

[0103] In the embodiment shown in Figures 1 to 7, the filter device 15 having a plurality of tar removal filters 35 is used in a biomass power generation system using a gas engine 18, but the present invention is not limited to this. The filter device 15 may also be used in a biomass power generation system using a gas turbine. In this case, the same effects as those of the embodiment shown in Figures 1 to 7 can be achieved.

[0104] 1 to 7, either the slaked lime 62, the activated carbon 63, or the charcoal 64 is used, but two or more of these may be used. Alternatively, a plurality of filter devices 15 may be provided in series or in parallel, and each filter device 15 may use one or two or more different fillers 54 selected from the slaked lime 62, the activated carbon 63, and the charcoal 64.

[0105] 1 to 7, either slaked lime 62, activated carbon 63, or charcoal 64 is used, but sawdust 65 may be used in combination as the filler 54. Alternatively, a filter device 15 using slaked lime 62, activated carbon 63, or charcoal 64 and a filter device 15' using sawdust 65 may be used in combination in series or in parallel.

[0106] Furthermore, since the tar 25 is originally woody biomass and has a calorific value, it adheres to piping and the like and causes problems, so it was removed during regular inspections of the equipment and incinerated. In the tar removal filter 35 shown in Figures 1 to 7, the tar 25 adheres to the filler 54 and is solidified into briquettes. Therefore, the tar 25 solidified into briquettes and the filler 54 can be removed from the tray of the tar removal filter 35 (the lower wire mesh 53 of the tar removal filter 35) and fed into the gasifier 12 together with the wood chips 21 as fuel.

[0107] If the tar 25 does not solidify into briquettes when attached to the filler 54, it may be briquetted by a briquetting machine or the like and fed as fuel to the gasifier 12 together with the wood chips 21. This can ultimately reduce the amount of filler 54, which is waste, and also allows the tar 25 to be reused as fuel for the gasifier 12. As a result, by using the tar removal filter 35 using the filler 54 shown in Figures 1 to 7, the amount of waste can be reduced and power generation efficiency can be improved in a biomass power generation system compared to the conventional system.

[0108] Furthermore, the facility in which the filter device 15 having the tar removal filter 35 is used is not limited to a biomass power generation system such as the gasification power generation system 1. For example, the filter device 15 having the tar removal filter 35 may be used in a carbonization facility in which a gas containing tar 25 is generated together with a carbonized product when organic matter such as garbage, sludge, or wood is pyrolyzed in a carbonization furnace. The filter device 15 may also be used in a facility such as an automobile company's experimental facility in which tar 25 is generated when engine exhaust gas is burned to remove VOCs (volatile organic compounds). In other words, the filter device 15 having the tar removal filter 35 can be used in other facilities and systems as well as biomass power generation systems as long as the facility discharges tar 25.

[0109] The features and advantages of the embodiments will be apparent from the above detailed description. It is intended that the claims cover the features and advantages of the embodiments as described above without departing from the spirit and scope of the claims. In addition, any improvements and modifications can be easily made by a person having ordinary skill in the art. Therefore, it is not intended to limit the scope of the inventive embodiments to the above, and appropriate improvements and equivalents within the scope of the embodiments disclosed can be used. [Explanation of symbols]

[0110] 1...Gasification power generation system; 11...Hopper; 12...Gasification furnace; 13...Produced gas cooler; 14...Wet electrostatic precipitator; 15, 15'...Filter device; 16...Booster fan (fan); 17...HEPA filter; 18...Gas engine; 19...Heat exchanger; 20...Exhaust tower; 21...Wood chips; 23...Gasification agent; 24...Combustible gas (fuel gas); 25...Tar; 26...Tar-containing water; 27 ...Exhaust gas;28...Hot water;31...Main body of device;33...Filter installation frame;34...Door;35, 35'...Tar removal filter;36...Inlet;37...Outlet;41...Shelf;42...Baffle plate;51...Frame;52...Upper wire mesh;52a...Holding part;53...Lower wire mesh;53a...Crimped wire mesh;53b...Wire mesh;54...Filling material;61...Limestone;62...Slaked lime;63...Activated carbon;64...Smoked charcoal;65...Sawdust

Claims

1. A flat cylindrical frame having an open upper surface and a closed lower surface; A filler material filled inside the frame; An upper wire mesh provided at an opening portion of the upper surface of the frame; a lower wire mesh provided at an opening in the lower surface of the frame and having mesh sizes finer than at least the size of the filler; Equipped with The filler is slaked lime or charcoal. A tar removal filter.

2. The tar removal filter according to claim 1, After the tar contained in the gas adheres to the filler and solidifies, the filler is removed from the wire mesh and put into the gasification furnace together with wood chips. A tar removal filter.

3. a tar removal filter including a flat cylindrical frame having an open top and bottom, a filler packed inside the frame, an upper wire mesh provided in the open portion of the top surface of the frame, and a lower wire mesh provided in the open portion of the bottom surface of the frame and having a mesh size at least finer than the size of the filler; a filter installation frame having a plurality of shelves on which the tar removal filter is detachably held and which are arranged parallel to the gas flow direction at predetermined intervals, and a flow straightening plate which divides adjacent two of the shelves at an angle with respect to the gas flow direction; Equipped with The filler is either hydrated lime, activated carbon, or charcoal. A filter device comprising:

4. 4. The filter device according to claim 3, The filter device further includes a main body having the filter installation frame therein, The shelves are arranged vertically at predetermined intervals, The straightening plate is arranged to divide the two adjacent upper and lower shelves by inclining downward toward the downstream side of the gas sent into the inside of the device body. A filter device comprising:

5. The filter device according to claim 3 or 4, After the tar contained in the gas adheres to the filler and solidifies, the filler is removed from the wire mesh and put into the gasification furnace together with wood chips. A filter device comprising:

Images