JP6523007B2 - Fluidized bed incinerator - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a fluidized bed incineration apparatus which fluidizes and incinerates an object to be treated by flowing air supplied to a fluidized bed incinerator.

  As such a fluidized bed incineration facility, for example, Patent Document 1 discloses a fluidized bed furnace which burns an object to be treated such as sewage sludge while flowing it with flowing air, combustion exhaust gas discharged from the fluidized bed furnace and a flow An air preheater that exchanges heat with the air, a dust collector that removes dust from the combustion exhaust gas discharged from the air preheater, and a turbocharger that generates compressed air from the combustion exhaust gas that is dusted by the dust collector ( A pressurized flow furnace installation with a turbocharger) is described. The compressed air generated by the supercharger is supplied as fluidizing air to the fluidized bed furnace through the air preheater.

JP 2014-190572 A

  By the way, in such a fluidized bed incineration facility, the waste heat of the combustion exhaust gas discharged from the fluidized bed furnace and the combustion exhaust gas discharged from the air preheater is recovered by the waste heat boiler, and the combustion exhaust gas removed of dust is externally removed. Heat is recovered from the circulating water of the flue gas treatment tower that carries out treatment to discharge the

  However, especially when the material to be treated is sewage sludge, when the water content of the dewatered sludge decreases due to the improvement of the capacity of the dewatering facility, self-combustion operation is possible in the fluid bed furnace without the need for auxiliary fuel. The temperature may become too high and the amount of heat that can be recovered from the flue gas may increase. Thus, when the amount of heat of the flue gas increases, the temperature of the fluidizing air preheated in the air preheater also rises, which results in a further rise in the combustion temperature of the fluidized bed furnace.

  Here, as means for coping with such an increase in the amount of incineration heat, for example, it is conceivable to suppress the combustion temperature by spraying water in a fluidized bed furnace, but the amount of combustion exhaust gas is increased by the evaporated spray water. Therefore, the exhaust gas processing equipment such as the dust collector must be upsized. In addition, there is a means to lower the temperature of the fluidizing air that is preheated in the air preheater, but it is difficult to control the operation stably, and the means to increase heat recovery with the boiler structure in the fluidized bed furnace becomes complicated equipment And increase costs.

  Furthermore, sewage sludge is increasingly treated intensively, and fluctuations in the properties of sludge such as moisture content and calorific value are greater than ever before, and stable operation of fluidized bed incineration equipment can be achieved. It is getting difficult. And these problems become more remarkable especially in the above-mentioned pressurized fluidized bed furnace supply which supplies compressed air generated by combustion exhaust gas to a fluidized bed furnace as flowing air.

  The present invention has been made under such a background, and stable and easy operation control can be performed even if the property of the object to be treated changes, without increasing the size, complexity, and cost of the facility. Aims to provide a fluid bed incinerator capable of

In order to solve the above problems and achieve such an object, the present invention comprises a fluidized bed incinerator that burns an object while flowing with flowing air, and the combustion discharged from the fluidized bed incinerator. And an air preheater for exchanging heat between the exhaust gas and the flow air, and a preheating air duct for supplying the flow air, which has been heat-exchanged in the air preheater, to the fluidized bed incinerator, A plurality of Stirling engine generators are spaced in the air duct in the flow direction of the flow air in the preheating air duct, and the Stirling engine generators adjacent to each other in the flow direction of the flow air are the preheats. It is characterized in that it is helically disposed and attached so as to be at different positions in the circumferential direction of the air duct .

  As is well known, a Stirling engine generator, for example, connects a displacer piston housed in a cylinder and a power piston to a crankshaft, makes one end of this cylinder a heater (heating unit) and the other end a cooling unit As a result, the crankshaft is rotated by the volume change of the gas in the cylinder due to the temperature difference, power is generated by the generator connected to the crankshaft, and the start-up time is short.

  Therefore, in a fluidized bed incinerator of the above configuration in which a plurality of such Stirling engine generators are attached to the preheating air duct that supplies the fluidizing air heat-exchanged in the air preheater to the fluidized bed incinerator, When the heat of combustion exhaust gas increases and the heat quantity of the combustion exhaust gas increases, the fluidizing air is cooled by starting the Stirling engine generator to promptly burn the combustion temperature in the fluidized bed incinerator and the exhaust gas temperature of the combustion exhaust gas While being stabilized, surplus heat can be recovered as electric power.

  Further, by adjusting the number of Stirling engine generators to be started according to the combustion temperature, it is possible to cope with the change easily and finely even if the combustion temperature changes due to the fluctuation of the property of the object to be treated. Moreover, since a plurality of Stirling engine generators may be attached to the preheating air duct, a large-scale exhaust gas treatment facility may be required as in the case of spraying water in the fluidized bed incinerator, or the fluidized bed incinerator may have a boiler structure. There are few cases where the equipment becomes complicated as in the case of

  Furthermore, since the Stirling engine generator is attached to the clear fluidizing air preheated by the air preheater, the heater of the Stirling engine generator may be heated by direct exposure to the fluidizing air, for example, combustion may occur. As in the case where heat is recovered by exposing the heating portion to the exhaust gas, damage such as abrasion does not occur due to the particulate component in the combustion exhaust gas. For this reason, a heating part can be penetrated in a preheating air duct, a Stirling engine generator can be attached, and it becomes possible to aim at heat recovery by efficient power generation.

  Also, by mounting multiple Stirling engine generators spaced apart in the flow direction of the flow air in the preheating air duct, Stirling engine power generation in the preheating air duct as described above when the inner diameter of the preheating air duct is small Even when the heating part of the machine is penetrated and attached, it is possible to prevent heat parts from interfering with each other to perform more efficient heat recovery, and also to prevent the flow of flowing air in the preheating air duct. Absent.

  Furthermore, when a plurality of Stirling engine generators are attached at intervals in the flow air supply direction as described above, the Stirling engine generators adjacent to each other in the flow air supply direction are arranged in the circumferential direction of the preheating air duct. By mounting at different positions, it is possible to prevent the heating by the flow air to the Stirling engine generator located on the supply direction side from being hindered and to further stabilize the flow of the flow air in the preheating air duct . In addition, when a plurality of Stirling engine generators are attached at intervals in the flow direction of the flow air, the Stirling engine generator located closest to the air preheater among the plurality of Stirling engine generators is also used. By providing control means for sequentially starting the Stirling engine generator in the flow direction of the flow air toward the incinerator side, heat can be recovered from the flow air at a higher temperature, which is efficient. When the Stirling engine generator is additionally started, the amount of heat of the fluidizing air supplied to the already-started Stirling engine generator does not fluctuate, so stable power generation can be performed.

  Thus, in particular, the above-described arrangement according to the invention is as described in US Pat. No. 5,956,015, in which the flow air is supplied to the air preheater via a turbocharger driven by the flue gas discharged from the air preheater. It is effective because the combustion temperature in the fluidized bed incinerator tends to be high when applied to pressurized fluidized bed furnace equipment.

  In the present invention, although it is essential that a plurality of Stirling engine generators be attached to the preheating air duct, this does not prevent attaching the Stirling engine generators to other places. For example, in addition to the preheating air duct, another Stirling engine generator is attached to the fluidized bed incinerator, and the temperature of the combustion exhaust gas is low depending on the properties of the object to be treated although the temperature of the preheated fluidizing air is low. If so, other Stirling engine generators may be activated to recover heat.

  As described above, according to the present invention, it is possible to cope with the change of the combustion temperature of the fluidized bed incinerator easily and promptly due to the change of the property of the object to be treated without increasing the size and complexity of the equipment. It is possible to perform stable operation control of the fluidized bed incinerator.

FIG. 1 is a schematic view of a fluidized bed incinerator showing an embodiment of the present invention. It is an (a) top view of the preheating air duct in an embodiment shown in Drawing 1, and (b) a side view.

  1 and 2 show one embodiment of the fluidized bed incinerator of the present invention. The disclosed technology is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. In FIG. 1, reference numeral 1 denotes a pressurized fluidized bed incinerator which burns while moving an object to be treated, and a fluidized medium is filled in the fluidized bed incinerator 1. Material to be treated such as sewage sludge, human waste sludge, food waste, food waste, municipal waste, etc. supplied to the inside is made to flow with the fluid medium by the high temperature, high pressure fluid air A supplied from the hearth section. It is heated and burned. In the fluidized bed incinerator 1, a state of the combustion temperature, exhaust gas temperature, pressure, etc. in the furnace, which is not shown, is measured, and a thermometer or the like is output to the control means of the incinerator which is not shown. An instrumentation device such as a pressure gauge is provided.

  The high-temperature combustion exhaust gas B generated by burning the material to be treated in the fluidized bed incinerator 1 is supplied to, for example, a shell-and-tube air preheater 2, and is supplied to the fluidized bed incinerator 1 for flowing air A The flow air A is heated to a high temperature by heat exchange therebetween. The flue gas duct connecting the flue gas outlet of the fluidized bed incinerator 1 and the air preheater 2 is provided with a thermometer (not shown) for measuring the flue gas temperature and outputting it to the control means.

  Thus, the flue gas B which has heated the fluidizing air A in the air preheater 2 is supplied to the dust collector 3 and dust and the like contained in the flue gas B are removed. The dust collector 3 is, for example, a bag filter provided with a large number of cylindrical ceramic filters with a bottom, and when the combustion exhaust gas B passes through the ceramic filter having fine pores, dust etc. in the combustion exhaust gas B is trapped. By collecting and removing dust, the flue gas B is cleaned.

  The flue gas B purified by the dust collector 3 is supplied to the turbocharger 4. The supercharger 4 includes a turbine that is supplied with the cleaned flue gas B and is rotated at high speed, and a compressor that is coaxially connected to the turbine and generates high-pressure compressed air by integrally rotating at high speed. It is a well-known, so-called turbocharger equipped. The atmosphere C is drawn into the compressor of the supercharger 4 through a filter or the like and supplied, and the compressed air generated in the compressor is supplied to the air preheater 2 as the flow air A, as described above. Heat is exchanged with the flue gas B.

  In this way, after the flue gas B which generated compressed air in the supercharger 4 is supplied to the white smoke preventing heat exchanger 5 and heat-exchanged with the white smoke preventing air D, the flue gas treating tower 6 By spraying the caustic soda water and water, impurities and the like are removed and the cooling process is performed. Furthermore, the cooled flue gas B is supplied to the chimney 7 and mixed with the white smoke preventing air D heat-exchanged by the white smoke preventing heat exchanger 5 to be heated, thereby preventing the generation of white smoke. It is discharged to the outside.

  A preheating air duct 9 is connected in series to a supply pipe 8 for supplying the fluidizing air A heat-exchanged in the air preheater 2 to the fluidized bed incinerator 1, and the preheating air duct 9 is provided. A plurality of Stirling engine generators 10 are attached. The preheating air duct 9 is attached to the middle of the supply pipe 8 when the pipe diameter of the supply pipe 8 is smaller than the length of the heater portion 10A of the Stirling engine generator 10 or when the pressure loss becomes too large. The central portion is formed in a cylindrical shape having a larger diameter than the supply pipe 8, and both end portions are formed in a tapered truncated cone shape, and are airtightly connected to the supply pipe 8.

  Further, in the Stirling engine generator 10, for example, the displacer piston and the power piston connected to the crankshaft as described above are accommodated in a cylinder, and one end of this cylinder is used as the heater unit (heating unit) 10A. At the same time, the other end is a cooling unit 10B supplied with cooling water to be cooled, and a generator 10D is connected to a case 10C in which a crankshaft is housed. The Stirling engine generator 10 of the present embodiment has the heater 10A penetrating from the outside to the inside of the preheating air duct 9, and the cooling part 10B, the case 10C, and the generator 10D are located outside the preheating air duct 9. It is airtightly attached to the preheating air duct 9.

  Furthermore, in the present embodiment, a plurality of (for example, four as shown in FIG. 2) Stirling engine generators 10 are provided in the supply direction F of the flow air A in the preheating air duct 9 as shown in FIG. It is attached at intervals. The Stirling engine generators 10 adjacent to each other in the supply direction F of the flow air A are attached at different positions in the circumferential direction of the preheating air duct 9.

  Specifically, as shown in FIG. 2, the plurality of Stirling engine generators 10 according to the present embodiment are disposed at equal intervals in the supply direction F, and those adjacent in the supply direction F are preheated air ducts The positions are shifted at equal intervals also in the circumferential direction of 9. Moreover, these Stirling engine generators 10 are arranged so as to shift the position in one circumferential direction (in the present embodiment, clockwise direction when viewed from the supply direction F side) in the supply direction F and make one turn around the preheating air duct 9. Are disposed, ie, arranged in a spiral.

  In such a fluidized bed incinerator, during normal operation, fluidizing air A preheated to a constant preheating temperature (for example, 650 ° C.) from the air preheater 2 flows through the supply pipe 8 and the preheating air duct 9 into a fluidized bed. By being supplied to the incinerator 1 and the material to be treated being burned at a constant combustion temperature, a flue gas B having a constant exhaust gas temperature is also generated. In addition, when the respective temperatures are constant and stable normal operation is performed as a matter of course, the Stirling engine generator 10 is stopped at the start of the fluidized bed incineration facility to reduce the amount of auxiliary fuel used at the start.

  Here, the combustion temperature of the fluidized bed incinerator 1 becomes a temperature (for example, 850 ° C. or higher) higher than the above-mentioned certain combustion temperature due to the fluctuation of the property of the material to be treated supplied. When the temperature (for example, 840 ° C. or higher) becomes higher than the constant exhaust gas temperature, this is detected by the fluid bed incinerator 1 or the thermometer provided in the flue gas duct, and the control means is used. Of the plurality of Stirling engine generators 10, first, one Stirling engine generator 10 on the side closest to the air preheater 2 is activated, power is generated using the flow air A as a heat source, and the temperature of the flow air A is constant Maintain at or below the above constant temperature.

  Furthermore, even if the Stirling engine generator 10 at the side of the air preheater 2 is started up in this way, the combustion temperature or the exhaust gas temperature does not decrease, or the increase of the combustion temperature or the exhaust gas temperature does not stop. When the exhaust gas temperature (eg, 850 ° C. or higher) is reached, start one Stirling engine generator 10 located next to the air preheater 2 next to the Stirling engine generator 10 on the air preheater 2 side. Decrease the temperature of the fluidizing air A. Thus, the Stirling engine generator 10 is sequentially started from the air preheater 2 side according to the combustion temperature of the fluidized bed incinerator 1 and the exhaust gas temperature of the combustion exhaust gas B to lower the temperature of the fluidizing air A, The temperature and exhaust gas temperature are returned to the above-described constant combustion temperature and exhaust gas temperature.

  Such a Stirling engine generator 10 has a short start-up time until the crankshaft stops rotating and starts from a stopped state, and the follow-up ability of temperature control is high, so the fluidized bed incineration facility with the above configuration causes combustion. Even if the temperature or exhaust gas temperature rises, it is possible to respond promptly. Further, since a plurality of Stirling engine generators 10 are attached to the preheating air duct 9, the combustion temperature and the exhaust gas temperature are adjusted by adjusting the number of the Stirling engine generators 10 to be started according to the combustion temperature and the exhaust gas temperature. It can be stabilized easily and finely in response to changes in Furthermore, the excessive heat can be efficiently recovered as electric power without causing the exhaust gas processing facility to be enlarged and the structure of the fluidized bed incinerator 1 to be complicated.

  Further, in the fluidized bed incineration plant having the above configuration, such a Stirling engine generator 10 is provided in the discharge passage of the combustion exhaust gas B from the fluidized bed incinerator 1 to the air preheater 2 to lower the exhaust gas temperature. Is attached to the preheating air duct 9 provided in the supply pipe 8 of the flow air A from the air preheater 2 to the fluidized bed incinerator 1 instead of lowering the preheating temperature of the flow air A by combustion. The former clear air for flow A is used as a heat source.

  Therefore, even if the heater portion 10A is penetrated into the preheating air duct 9 and exposed directly to the combustion air A as in the present embodiment, the particle component in the combustion exhaust gas B as in the case of exposure to the combustion exhaust gas B It is possible to achieve stable control of the combustion temperature and the exhaust gas temperature over a long period of time without causing the heater portion 10A to be worn and damaged. In addition, since the heater unit 10A can be directly exposed to the combustion air A to perform power generation, efficient heat recovery can also be promoted.

  In particular, as in the present embodiment, in the pressurized flow furnace facility in which the flow air A is supplied to the air preheater 2 via the supercharger 4 driven by the combustion exhaust gas B discharged from the air preheater 2 Since the fluidizing air A pressurized by the supercharger 4 is supplied to the fluid bed incinerator 1, the combustion temperature in the fluid bed incinerator 1 and the exhaust gas temperature of the flue gas B tend to be high, and fluctuations also occur large. For this reason, it is effective to achieve the stabilization of the combustion temperature and the exhaust gas temperature by applying the above-described configuration to such a pressurized flow furnace facility.

  On the other hand, in the present embodiment, the plurality of Stirling engine generators 10 are attached at intervals in the supply direction F of the flow air A in the preheating air duct 9 and the Stirling is performed when the inner diameter of the preheating air duct 9 is small. Even when the heater unit 10A of the engine generator 10 is penetrated and attached, the heater units 10A of the Stirling engine generator 10 adjacent in the supply direction F can be prevented from interfering with each other.

  Therefore, as shown in FIG. 2 (a) in particular, even when the heater portion 10A penetrates so as to project beyond the center of the preheating air duct 9, a plurality of Stirling engine generators 10 do not generate interference. To ensure reliable heat recovery. In addition, it is possible to prevent the stable flow of the flowing air A in the preheating air duct 9 from being disturbed as in the case where the heater portion 10A protrudes to the same position in the supply direction F. Furthermore, higher temperature can be achieved by controlling the Stirling engine generator 10 thus spaced in the supply direction F by the control means to start up from the Stirling engine generator 10 closest to the air preheater 2 as described above. This is efficient because heat can be recovered from the flowing air A. In addition, the Stirling engine generator 10 was additionally started by sequentially starting the Stirling engine generator 10 positioned from the Stirling engine generator 10 located closest to the air preheater 2 toward the fluid bed incinerator 1 side In this case, the amount of heat of the fluidizing air A supplied to the Stirling engine generator 10 that has already been started does not fluctuate, so stable power generation can be performed.

  Further, in the present embodiment, in addition to the plurality of Stirling engine generators 10 being attached at intervals in the supply direction F of the flow air A in this way, the Stirling engine generators 10 adjacent to the supply direction F are also provided. They are attached at different positions in the circumferential direction of the preheating air duct 9 as well. Therefore, the heater portion 10A of the Stirling engine generator 10 adjacent to the supply direction F side (fluid bed incinerator 1 side) by the heater portion 10A of the Stirling engine generator 10 on the near side (air preheater 2 side) of the supply direction F It is possible to prevent heat from being disturbed by the fluidizing air A, and to achieve more reliable heat recovery. Further, the flow of the flow air A in the preheating air duct 9 can be further stabilized.

  In particular, in the present embodiment, as described above, the Stirling engine generator 10 is spirally disposed in the preheating air duct 9, and until the spiral makes a round, the Stirling engine generator 10 on the supply direction F side is The heater portion 10A of the next Stirling engine generator 10 does not protrude in the opposite direction to the supply direction F of FIG. For this reason, on at least the other end side of the cylinder of the Stirling engine generator 10, the heater unit 10A can be exposed to the high temperature flowing air A, and heat can be recovered more efficiently.

  In the present embodiment, a plurality of preheating air ducts 9 larger in diameter than the supply pipe 8 are connected in the middle of the supply pipe 8 for supplying the fluidizing air A from the air preheater 2 to the fluidized bed incinerator 1. However, if the supply pipe 8 has a sufficiently large diameter, the supply pipe 8 itself may be used as a plurality of preheated air ducts without connecting such a preheated air duct 9 separately. A Stirling engine generator 10 may be attached.

Furthermore, although the preheating air ducts 9 extend in the vertical direction in FIGS. 1 and 2, a plurality of Stirling engine generators 10 may be attached to the horizontally extending preheating air ducts 9.

  Further, in connection with attaching a plurality of Stirling engine generators 10 to the preheating air duct 9 for supplying the fluidizing air A heat-exchanged in the air preheater 2 to the fluid bed incinerator 1, reference numeral in FIG. Another Stirling engine generator may be attached to the fluidized bed incinerator 1 as indicated at 11.

  For example, if another Stirling engine generator 11 is attached near the discharge portion of the flue gas B at the top of the fluidized bed incinerator 1 as shown in the drawing, the temperature of the preheated fluidizing air A is low, When the temperature of the combustion exhaust gas B is high due to the properties of the object to be treated, the temperature of the combustion exhaust gas B is reduced without lowering the temperature of the flow air A more than necessary by activating the other Stirling engine generator 11 Heat recovery can be done together with

  In the present embodiment, although the starting condition of the Stirling engine generator 10 is the combustion temperature of the fluidized bed incinerator 1 or the exhaust gas temperature in the flue gas duct, the fluid flows through the preheating air duct 9 and the supply pipe 8. A thermometer may be provided to measure the temperature of the air A, and the temperature of the flowing air A may be set as a start condition.

DESCRIPTION OF SYMBOLS 1 fluid bed incinerator 2 air preheater 3 dust collector 4 supercharger 5 white smoke prevention heat exchanger 6 smoke exhaust processing tower 7 chimney 8 supply pipe of flow air A 9 preheating air duct 10 Stirling engine generator 10A heater part 10B Cooling part 10C Case 10D generator 11 Other Stirling engine generator A Flowing air B Combustion exhaust gas C Air D White smoke prevention air F Supply direction

Claims (4)

A fluidized bed incinerator which burns an object to be treated by flowing air while flowing an object, an air preheater which exchanges heat between the flue gas discharged from the fluidized bed incinerator and the flowing air, and the air And a preheated air duct for supplying the fluidizing air heat-exchanged in the preheater to the fluidised bed incinerator, the plurality of Stirling engine generators in the preheated air duct, the fluidizing air in the preheated air duct The Stirling engine generators adjacent to each other in the flow direction of the flow air are arranged in a spiral so that they are at different positions in the circumferential direction of the preheating air duct. A fluidized bed incinerator characterized by Among the plurality of Stirling engine generators, the Stirling engine generator is sequentially activated in the flow direction of the fluidizing air from the Stirling engine generator located closest to the air preheater toward the fluid bed incinerator side. The fluidized bed incineration system according to claim 1 , characterized in that the control means is provided. The fluidizing air is set forth in claim 1 or claim 2, characterized in that it is supplied to the air preheater through a supercharger driven by the combustion exhaust gas discharged from the air preheater Fluid bed incinerator. The fluidized bed incinerator according to any one of claims 1 to 3 , wherein another Stirling engine generator is attached to the fluidized bed incinerator.

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