JP2005125265A - Treating method and treating system of organic waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treating method capable of effectively utilizing an organic waste since the efficiency of a gas turbine can be improved and an active carbide is manufactured by carbonizing the organic waste. <P>SOLUTION: The treating method of the organic waste that the gas turbine generator 2 is put side by side with a charring (activation) furnace 3, a dehydrated cake of the organic waste is dried and is supplied to the furnace 3 to perform a carbonizing treatment while supplying electric power to the furnace 3 and others, wherein a turbine exhaust gas G exhausted from the gas turbine is supplied to the turbine 3 and is burned with a firework fuel J, the dried dehydrated cake S is thermally decomposed and carbonized in a reductive atmosphere, an active carbide C is recovered, the potential heat of the carbide exhaust gas H from the furnace 3 is thermally recovered through a heat exchanger 5 and is used to dry the dehydrated cake S, is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and a treatment system for carbonizing organic waste containing carbon, particularly sludge generated from sewage treatment plants, water purification plants, and other food waste, and more specifically, a gas turbine power generation system. This is based on the premise that a high oxygen concentration exhaust gas is effectively used for carbonization with the addition of a machine.

  Since the above gas turbine alone has poor heat efficiency and low power generation efficiency, improvement in power generation efficiency is regarded as a demand.

  In recent years, research on effective use of organic waste has been actively conducted, and various technologies such as biogasification, composting, and carbonization are being established.

  In this type of prior art, for example, as an apparatus for producing activated carbide from a carbonized raw material, a carbonization tube having a screw conveyor provided therein is installed in the combustion furnace to constitute a carbonization furnace, and the carbonized raw material is carbonized by a supply device. It is supplied into the pipe and subjected to indirect heat treatment, the carbonized raw material is dried at the front stage of the carbonization pipe to generate water vapor, carbonized at the middle stage to generate water vapor and pyrolysis gas, and the carbide at the rear stage by steam and pyrolysis gas. The thing of the structure which activates and activates and manufactures activated carbide is proposed (for example, refer to patent documents 1).

  In addition, it consists of a sludge drying and firing facility that dries and calcines sludge containing high moisture, and a gas turbine generator that supplies power to this sludge drying and firing facility and related equipment, and high-temperature exhaust gas from the gas turbine generator. A sludge resource recycling method has been proposed in which at least a part of the sludge is supplied to a hot air dryer / high temperature calciner of a sludge drying and firing facility to dry and burn the sludge (see, for example, Patent Document 2).

In addition, it has been proposed to use digestion gas obtained by subjecting organic matter to methane fermentation for fuel cell power generation (see, for example, Patent Document 3).
JP 2001-322809 A (paragraph numbers 0008, 0009, 0019) JP-A-8-61646 (Claim 1, paragraph numbers 0008, 0017) Japanese Patent Laid-Open No. 2001-23677 (paragraph numbers 0020 to 0022, FIG. 1)

  In the sludge resource recycling method described above, a gas turbine is provided in the sludge drying and firing facility, and the exhaust gas from the gas turbine is supplied to a hot air dryer and a high-temperature calciner to be used for drying and firing the sludge. In this method, the sludge is dried or baked, and thus cannot be effectively used. In addition, although the amount of exhaust gas varies depending on the operating condition of the gas turbine, in the sludge drying and firing facility, it is necessary to increase or decrease the combustion amount in accordance with the change in the amount of exhaust gas, and the control is complicated. The air supplied to the gas turbine generator has an oxygen concentration of about 21%. However, the gas turbine hardly consumes oxygen, and exhaust gas with an oxygen concentration of 17 to 19% is discharged. Since it has heat, it should be used effectively.

  In the present invention, by combining a gas turbine generator with a carbonization furnace, ideal combustion can be achieved by both, the efficiency of the gas turbine can be improved, and organic waste is carbonized to produce activated carbide for effective use. It aims at providing the processing method and processing system of organic waste which can be planned.

In order to achieve the above object, the organic waste processing method according to the present invention includes a gas turbine generator in a carbonization furnace (carbonization activation furnace), and supplies organic power while supplying power to the carbonization furnace and others. An organic waste treatment method for drying a dehydrated cake of waste and supplying it to the carbonization furnace for carbonization,
Combustion exhaust gas discharged from the gas turbine is supplied to the carbonization furnace and combusted with auxiliary fuel, and the dried dehydrated cake is pyrolyzed and carbonized in a reducing atmosphere to collect carbides, and from the carbonization furnace. The retained heat of the exhaust gas is recovered through a heat exchange means and used for drying the dehydrated cake.

  According to the treatment method of the present invention having the above configuration, the combustion exhaust gas discharged from the gas turbine can be effectively used as a heat source necessary for carbonization of organic waste, and the exhaust gas after being used for carbonization is also heated. Heat can be recovered by the exchange means and used as a heat source for drying the dehydrated cake. In this way, oxygen in the air with an oxygen concentration of about 21% introduced into the gas turbine generator is consumed in stages, and finally exhausted as an exhaust gas with an oxygen concentration of 9% or less (preferably around 6%). The thermal efficiency can be improved. In addition, activated carbon can be produced from organic waste and used as a dioxin adsorbent or deodorant.

  As described in claim 2, water is heated by the exhaust gas from the carbonization furnace to generate water vapor, a part of the water vapor is used for drying the dewatered cake, and a part of the water vapor is supplied to the gas turbine. The water vapor can be introduced into the chain cycle and used for air cooling for cooling air for introducing the remainder of the water vapor into the gas turbine.

  According to the processing method of claim 2, since the combustion exhaust gas discharged from the gas turbine is used for carbonization of the organic waste, it is converted into water vapor and heat is recovered, so that it can only be used as a heat source for drying the dehydrated cake. For example, a chain cycle system in which steam is blown into the gas turbine can be adopted, or air can be cooled with a cooler using steam as a heat source and blown into the gas turbine to lower the intake air temperature. It can be greatly improved.

  As described in claim 3, by using heat recovery through the heat exchange means, heated air or superheated steam at 200 ° C. or higher (preferably 450 to 650 ° C.) is used for drying the dehydrated cake, and The supply amount of auxiliary fuel is controlled so that the temperature of the carbonization furnace is maintained at 900 ° C. or higher (preferably 950 ° C.), and the oxygen concentration of the exhaust gas that has passed through the heat exchange means is 9% or lower (preferably 6%). The power generation amount of the gas turbine can be controlled so as to be maintained.

  According to the processing method of the third aspect, the activated carbide can be produced from the organic waste with high efficiency, and the thermal efficiency of the entire processing system is improved.

In order to achieve the above object, a processing system according to claim 4, wherein a gas turbine generator is provided in the carbonization furnace, and the dehydration cake of organic waste is dried while supplying power to the carbonization furnace and others. An organic waste treatment system for carbonization by supplying to a carbonization furnace,
A heat exchanger for recovering the heat of the exhaust gas discharged from the carbonization furnace to generate superheated steam or heated air, and drying the dehydrated cake with the superheated steam or heated air supplied from the heat exchanger, And a drier for supplying to the carbonization furnace.

  According to the organic waste processing system, the processing method according to the first aspect can be reliably implemented.

  6. The exhaust gas exhaust pipe exhausted from the heat exchanger is equipped with an exhaust gas temperature sensor and an oxygen concentration sensor, respectively, and one end of the branch circulation pipe branched from the exhaust pipe is connected to the carbonization furnace. The circulation flow control valve is automatically opened according to the temperature of the exhaust gas measured by the temperature sensor by providing a circulation flow control valve in the branch circulation pipe. A fuel injection amount adjustment mechanism that adjusts and controls the fuel injection amount in accordance with the oxygen concentration value of the exhaust gas may be provided.

In this way, the load (power generation amount) of the gas turbine can be controlled so that the oxygen (O ₂₎ concentration of the exhaust gas is maintained at 9% or less (preferably 6%). That is, if the oxygen concentration increases, control is performed to reduce the power generation load so that the amount of gas turbine combustion exhaust gas, which is carbonization combustion air, decreases. Conversely, if the oxygen concentration of the exhaust gas decreases, the combustion exhaust gas from the gas turbine Control is performed so as to increase the power load so as to increase the amount of the heat, and the thermal efficiency of the entire processing system can be improved. In addition, since the circulation air volume of the exhaust gas discharged from the heat exchanger and circulated to the carbonization furnace can be controlled by automatically adjusting the opening of the circulation flow rate control valve according to the temperature of the exhaust gas, the exhaust gas discharged from the heat exchanger The outlet temperature can be maintained at 200 ° C., for example.

In order to achieve the above object, a processing system according to claim 6, wherein a gas turbine generator is provided in the carbonization furnace, and the dehydration cake of organic waste is dried while supplying electric power to the carbonization furnace and others. An organic waste treatment system for carbonization by supplying to a carbonization furnace,
A waste heat boiler for recovering the heat of exhaust gas discharged from the carbonization furnace to generate superheated steam, a water supply device for supplying water to the waste heat boiler and for supplementing the amount consumed by the waste heat boiler, A dryer for drying the dehydrated cake with the superheated steam supplied from the waste heat boiler and supplying it to the carbonization furnace, and cooling the air with the superheated steam supplied from the waste heat boiler and introducing it into the gas turbine And a supply passage for supplying superheated steam from the waste heat boiler to the gas turbine.

  According to this organic waste processing system, although the number of equipment is increased as compared with the processing system according to claim 4, it is possible to perform a turbine chain cycle and to lower the intake air temperature for introducing the turbine. Power generation efficiency is greatly improved (about 20 to 30%). In other words, the processing method according to claim 2 can be reliably performed.

  The temperature sensor and oxygen concentration sensor of the exhaust gas are respectively attached to the exhaust pipe of the exhaust gas discharged from the heat exchanger, and one end of the branch circulation pipe branched from the exhaust pipe is connected to the carbonization furnace. Connected to the vicinity of the combustion exhaust gas inlet, and a circulation flow rate adjustment valve is provided in the branch circulation pipe to automatically open the circulation flow rate adjustment valve according to the temperature of the exhaust gas measured by this temperature sensor. The oxygen concentration sensor and the in-furnace temperature sensor provided in the carbonization furnace are connected to a flow rate adjusting valve for adjusting the amount of auxiliary fuel supplied to the carbonization furnace, respectively, and the carbonization furnace temperature and exhaust gas oxygen are connected. The auxiliary fuel supply amount can be controlled in accordance with a change in concentration.

  In this way, the temperature of the carbonization furnace can be maintained at 900 ° C. or higher, preferably 950 ° C. by controlling the auxiliary fuel supply amount. That is, the amount of auxiliary fuel supplied to the carbonization furnace is basically controlled by the carbonization temperature, and the control based on the oxygen concentration of the exhaust gas discharged from the heat exchanger is + or -Change command is given. This changes the amount of carbonized exhaust gas and the amount of surplus steam from the waste heat boiler.For example, when the oxygen concentration of the exhaust gas is high, the amount of auxiliary fuel increases, the amount of steam from the waste heat boiler increases, and the gas turbine chain cycle and Gas turbine inlet air temperature cooling capacity is increased. Further, the outlet temperature of the exhaust gas discharged from the waste heat boiler can be maintained at 200 ° C., for example, by controlling the circulation air volume of the exhaust gas circulated to the carbonization furnace by the opening degree of the circulation valve. Furthermore, the load (power generation amount) of the gas turbine can be controlled so that the oxygen concentration of the exhaust gas is maintained at 9% or less (preferably 6%), and the thermal efficiency of the entire processing system can be improved. Furthermore, when the surplus steam from the waste heat boiler is increased by the above control of the carbonization system, the chain cycle and the inlet air are cooled, and the amount of turbine power generation is increased.

  According to the organic waste processing method or processing system of the present invention, ideal combustion can be achieved by combining a gas turbine generator with a carbonization furnace, the efficiency of the gas turbine can be improved, and organic waste can be improved. Since the activated carbon is produced by carbonizing the product, the organic waste can be effectively used.

  In the processing method according to the first aspect of the present invention and the processing system according to the fourth aspect of the present invention, the amount of gas turbine power generation that brings about the best thermal efficiency can be obtained according to the scale of carbonization.

  In the processing method of claim 2 and the processing system of claim 5, organic waste processing such as sewage sludge and power generation can be performed with thermal efficiency close to the best according to the scale of turbine power generation and carbonization and their balance. Further, the processing system according to claim 5 increases the number of equipment and makes the structure somewhat complicated. However, since heat recovery is performed with steam, a turbine chain cycle can be performed. This increases power generation efficiency by about 20%. Further, the power generation efficiency is increased by about 10% by lowering the intake air temperature when the turbine is introduced.

(Example 1)
FIG. 1 is a flow diagram schematically showing an embodiment in which the treatment system of the present invention is applied to the treatment of sewage sludge. As shown in FIG. 1, the treatment system 1 of this example includes a carbonization (activation) furnace 3 for producing activated carbide C by carbonizing and activating sewage sludge generated in the sewage treatment plant. It is installed in combination with a gas turbine generator 2 in which a generator is connected to a gas turbine. The gas turbine generator 2 and the carbonization (activation) furnace 3 are known, and the carbonization (activation) furnace 3 having the following structure described in, for example, Japanese Patent No. 2975011 is used.

  As shown in FIG. 2, the carbonization (activation) furnace 3 is provided with a metal cylindrical carbonization pipe 33 in which a screw conveyor 34 is housed in a furnace body 31, and is discharged from the gas turbine of the gas turbine generator 2. The turbine exhaust gas G is supplied from the inlet 32 into the furnace body 31. In the furnace main body 31, the turbine exhaust gas G supplied from the introduction port 32 is combusted by a burner (not shown) together with the auxiliary fuel J, which will be described later, and this combustion gas G ′ rises from below along the longitudinal direction of the carbonization tube 33. To the exhaust port 35 and discharged. On the other hand, the dried sludge T carried out from the dryer 4 is supplied into the carbonization pipe 33 from an inlet 33a provided at one end of the carbonization pipe 33, and indirectly through the carbonization exhaust gas H flowing in the furnace body 31. Heated. Then, carbonization is performed while the reducing atmosphere in the carbonizing pipe 33 is sequentially conveyed downstream by the screw conveyor 34. Further, the moisture contained in the dried sludge T is generated as water vapor in the carbonized pipe 33 and is used for the activation process together with the pyrolysis gas generated during the carbonization process of the dried sludge T in the downstream carbonized pipe 33. . The water vapor and pyrolysis gas filled in the carbonization pipe 33 are discharged into the furnace body 31 from the exhaust port 33b near the downstream end of the carbonization pipe 33, mixed with the turbine exhaust gas G, and burned. Further, the end portion is constituted by a cooling pipe 36, a water cooling mechanism 37 is mounted around the cooling pipe 36, and is connected to the carbonizing pipe 33 via a rotary valve 38. Then, the activated carbide C generated in the carbonizing pipe 33 is cooled while being conveyed in the cooling pipe 36 by the screw conveyor 34, and is taken out from the outlet 36a opened downward at the end.

  In this way, the dried sludge T supplied into the carbonization pipe 33 of the carbonization (activation) furnace 3 is carbonized in the carbonization pipe 33, and then activated and extracted as activated carbide C.

  In addition, heat exchange for recovering the heat of the carbonized exhaust gas H from the dryer 4 and the carbonization (activation) furnace 3 for drying the dewatered cake S obtained by dewatering the sewage sludge with a centrifuge etc. A vessel 5 is provided. In the main body 31 of the carbonization (activation) furnace 3, auxiliary fuel J, in this example heavy oil, is supplied to the vicinity of the introduction port 32 through the oil supply pipe 6 together with the turbine exhaust gas G. The fuel supply pipe 6 is provided with an auxiliary fuel injection pump 24 and an auxiliary fuel injection amount adjustment valve 7, and the auxiliary fuel injection amount is determined according to the furnace temperature measured by the furnace temperature sensor 18 mounted on the furnace body 31. The opening degree of the regulating valve 7 is automatically adjusted, and the supply amount of heavy oil is automatically adjusted.

  The dewatered cake S is fed to the dryer 4 through a feed pipe 8 provided with a feed pump 9 from a storage site (not shown). In the dryer 4, the dehydrated cake S is dried with heated air (or superheated steam). This heated air is heated by the heat of the carbonized exhaust gas H in the heat exchanger 5 and is sent to the dryer 4 through the supply pipe 10. It is done. The heated air is preferably 200 ° C. or higher, preferably 450 to 650 ° C. The heated air sent to the dryer 4 is returned to the heat exchanger 5 through the return pipe 12 and circulated. A flow rate adjusting valve 11 is provided in the middle of the supply pipe 10, and the opening degree of the flow rate adjusting valve 11 is automatically adjusted according to the temperature measured by the air temperature sensor 22 mounted on the return pipe 12.

  Exhaust gas I exhausted from the heat exchanger 5 is released from the exhaust pipe 13 into the atmosphere through a chimney (not shown) or the like, and the exhaust pipe 13 is provided with a temperature sensor 14 and an oxygen concentration sensor 15 for the exhaust gas I, respectively. Has been. Further, the exhaust pipe 13 is branched, and one end of the branch circulation pipe 16 is connected to the vicinity of the inlet 32 of the turbine exhaust gas G of the carbonization (activation) furnace 3. A circulation flow rate adjustment valve 17 is provided in the branch circulation pipe 16, and the opening degree of the circulation flow rate adjustment valve 17 is automatically adjusted according to the temperature of the exhaust gas I measured by the temperature sensor 14. Further, the oxygen concentration sensor 15 is connected to the fuel injection pump 23 of the gas turbine generator 2, and the fuel injection amount is controlled according to the oxygen concentration value of the exhaust gas I. Furthermore, the oxygen concentration sensor 15 and the pump 9 are connected, the rotational speed of the pump 9 is automatically controlled according to the oxygen concentration value of the exhaust gas I, and the supply amount of the dehydrated cake S fed to the dryer 4 is automatically set. Adjusted.

  The processing system 1 according to the present embodiment is configured as described above. Hereinafter, the control of the processing system 1 according to the present embodiment will be described in detail together with the processing method.

In the processing system 1 of FIG.
a) Drying system: The dewatered cake S of sewage sludge is put into the dryer 4. At this time, heated air of 200 ° C. or higher, preferably 450 to 650 ° C. is simultaneously introduced from the heat exchanger 5.

  On the other hand, in the dryer 4, the amount of the dehydrated cake S and the amount of heated air introduced are adjusted so that the exhaust temperature is maintained at 90 to 120 ° C.

  b) Carbonization system: The supply amount of heavy oil as auxiliary fuel J is adjusted so that the temperature in the furnace body 31 of the carbonization (activation) furnace 3 is maintained at 900 ° C. or higher, preferably 950 ° C.

  On the other hand, the circulation air volume of the exhaust gas I circulated to the carbonization (activation) furnace 3 is controlled by the opening degree of the circulation flow control valve 17 so that the outlet temperature of the exhaust gas I discharged from the heat exchanger 5 is maintained at 200 ° C. Is done. That is, when the heat source for drying the dewatering cake S increases, the outlet temperature of the exhaust gas I decreases, so the opening degree of the circulation flow rate control valve 17 increases and the amount of the exhausted gas to be circulated increases. As a result, the amount of carbonized exhaust gas H from the carbonization (activation) furnace 3 passing through the heat exchanger 5 increases.

  In order to improve the thermal efficiency of the entire processing system 1, the load (power generation amount) of the gas turbine is controlled so that the oxygen concentration of the exhaust gas I is maintained at 9% or less (preferably 6%). In other words, if the oxygen concentration increases, control is performed to reduce the power generation load so that the turbine exhaust gas amount G, which is carbonization combustion air, decreases.

  c) Gas turbine power generation system: The gas turbine itself performs fuel control according to fluctuations in the power load. And if the oxygen concentration of exhaust gas I falls, an electric power load will be raised so that the quantity of the combustion exhaust gas H from a gas turbine may be increased.

  In this way, the amount of power generation that brings about the best thermal efficiency according to the carbonization scale of the sewage sludge can be obtained. For example, the following cases 1 and 2 can be considered.

◎ Case 1: When the moisture content of the dehydrated cake S is large It is necessary to increase the amount of heat for drying the dehydrated cake S, and the circulation amount of the exhaust gas I to the carbonization (activation) furnace 3 is increased accordingly. Activation) The temperature of the furnace 3 decreases. Therefore, the supply amount of the auxiliary fuel J increases, the oxygen concentration of the exhaust gas I decreases, and the gas turbine power generation amount increases. In other words, when the power demand is high, the coagulant addition amount that determines the moisture content of the dewatered cake S is reduced, and the cost required for dewatering is reduced.

◎ Case 2: When power demand is low Increase the moisture content of the dehydrated cake S (increase the amount of flocculant added) and increase the amount of auxiliary fuel supplied.

  Table 1 below shows the relationship between the amount of power generation and the moisture content of the dehydrated cake (however, in the case of a treatment system equipped with a carbonization (activation) furnace for 100 ton / day of dehydrated cake).

(Example 2)
FIG. 3 is a flow diagram schematically showing another embodiment in which the treatment system of the present invention is applied to the treatment of sewage sludge. As shown in FIG. 3, the processing system 1 ′ of the present example is different from the first embodiment in the following configuration. That is, instead of the heat recovery heat exchanger 5, a waste heat boiler 19 is used, and a water supply device 20 for generating superheated steam is provided. Pure water is supplied from the water supply apparatus 20 to the waste heat boiler 19 through a water supply pipe 20a. Further, the oxygen concentration sensor 15 of the exhaust gas I and the in-furnace temperature sensor 18 of the carbonization (activation) furnace 3 are respectively connected to the auxiliary fuel injection amount adjusting valve 7 for adjusting the supply amount of auxiliary fuel, and the oxygen of the exhaust gas I Even in response to the change in concentration, the opening degree of the auxiliary fuel injection amount adjusting valve 7 is controlled so that the amount of auxiliary fuel supplied can be adjusted.

  Further, not only the superheated steam generated in the waste heat boiler 19 is supplied to the dryer 4 through the supply pipe 26 provided with the steam injection amount adjusting valve 27, but also supplied to the gas turbine via the steam injection amount adjusting valve 29. It is made available for a so-called chain cycle in which the output is increased by supplying and injecting with a pipe 28. The superheated steam is also used as a heat source for refrigerant regeneration of the cooler 21 for producing cooling air for increasing the efficiency of the gas turbine generator 2. That is, a part of the superheated steam is supplied to the cooler 21 for cooling the air to produce cooling air through the supply pipe 28a. In addition, pure water from the water supply device 20 is also supplied to the cooler 21. Other configurations are the same as those of the processing system 1 of the first embodiment, and therefore, common components are denoted by the same reference numerals and description thereof is omitted.

  The processing system 1 ′ according to the second embodiment is configured as described above. Hereinafter, the control of the processing system 1 ′ according to the present example will be described in detail together with a processing method.

In the processing system 1 ′ of FIG.
a) Drying system: The dewatered cake S of sewage sludge is put into the dryer 4. At this time, superheated steam at 200 ° C. or higher, desirably 450 to 650 ° C. is simultaneously introduced into the dryer 4 from the waste heat boiler 19. On the other hand, in the dryer 4, the introduction amount of superheated steam is adjusted so that the exhaust temperature is maintained at 90 to 120 ° C.

  Moreover, dry sludge is maintained so that a moisture content may be in the range of 10 to 30%.

  b) Carbonization system: The supply amount of heavy oil as auxiliary fuel is adjusted so that the temperature in the furnace body of the carbonization (activation) furnace 3 is maintained at 900 ° C. or higher, preferably 950 ° C. On the other hand, the circulation air volume of the exhaust gas I circulated to the carbonization (activation) furnace 3 is controlled by the opening degree of the circulation flow control valve 17 so that the outlet temperature of the exhaust gas I discharged from the waste heat boiler 19 is maintained at 200 ° C. Is done. That is, when the heat source for drying the dehydrated cake S increases, the outlet temperature of the exhaust gas I decreases, so the opening degree of the circulation flow rate control valve 17 increases, and the amount of exhaust gas to be circulated increases, so that it passes through the waste heat boiler 19. The amount of carbonized exhaust gas H from the carbonization (activation) furnace 3 increases. Further, in order to improve the thermal efficiency of the entire processing system 1 ′, the load (power generation amount) of the gas turbine is controlled so that the oxygen concentration of the exhaust gas I is maintained at 9% or less (preferably 6%).

  The auxiliary fuel for the carbonization (activation) furnace 3 is basically controlled by the carbonization temperature as described above, and the control by the oxygen concentration of the exhaust gas I changes + or-with respect to the control result defined by the carbonization temperature. Give a directive. As a result, the amount of carbonized exhaust gas H and the amount of surplus steam from the waste heat boiler 19 change. That is, when the oxygen concentration of the exhaust gas I is high, the amount of auxiliary fuel increases, the amount of steam from the waste heat boiler 19 increases, and the gas turbine chain cycle and the gas turbine inlet air temperature cooling capacity increase.

  c) Gas turbine power generation system: Gas turbines are fuel-controlled so that the amount of power generation is constant. The adoption of a chain cycle system that blows steam into the gas turbine improves power generation efficiency. Moreover, power generation efficiency can be improved by blowing cooling air and lowering the intake temperature of the gas turbine. Furthermore, if the surplus steam from the waste heat boiler 19 increases due to the control of the carbonization system, the chain cycle and the inlet air are cooled, and the amount of turbine power generation increases.

  In this manner, sewage sludge treatment and power generation are performed with thermal efficiency close to the best according to the scale of the gas turbine generator 2 and the carbonization (activation) furnace 3 and their balance.

  Here, the control loop with respect to the fluctuation | variation of the moisture content of the dewatering cake S which has a big influence on the amount of auxiliary fuel consumption in a sewage sludge process is demonstrated. For example, the following cases 1 and 2 can be considered.

◎ Case 1: When the moisture content of the dehydrated cake S is increased The moisture of the dehydrated cake S to be dried increases, and the exhaust gas temperature from the dryer 4 decreases. By controlling the exhaust gas temperature, the amount of steam from the waste heat boiler 19 increases. As a result, the outlet temperature of the exhaust gas I from the waste heat boiler 19 decreases, and the circulation amount of the exhaust gas I to the carbonization (activation) furnace 3 increases. When the circulation amount increases, the temperature of the carbonization (activation) furnace 3 increases. The auxiliary fuel supply amount increases and the oxygen concentration of the exhaust gas I decreases. On the other hand, since the amount of steam sent to the dryer 4 increases, the chain cycle to the gas turbine and the amount of steam supplied to the cooler 21 are insufficient, and the power generation efficiency of the gas turbine is reduced. Then, the fuel supply amount to the gas turbine increases and the turbine exhaust gas amount also increases. As a result, the oxygen concentration of the carbonized exhaust gas H in the carbonization (activation) furnace 3 is increased and recovered.

  When the treatment system 1 ′ is viewed as a whole, the power generation efficiency is reduced and the heat recovery rate of the exhaust gas H is increased, thereby controlling the increase of the heat source for drying the dewatered cake S of the sewage sludge.

Case 2: When the moisture content of the dewatered cake S is low The amount of steam used as a heat source for drying is reduced, and the amount of steam used in the gas turbine chain cycle and the cooler 21 for cooling air is increased. The power generation efficiency increases, the gas turbine introduction fuel decreases, the amount of combustion exhaust gas decreases, the oxygen concentration in the carbonization (activation) furnace 3 increases, and the auxiliary fuel in the carbonization (activation) furnace 3 decreases.

  If processing system 1 'is seen as a whole, it will be nothing but reducing the fuel consumption by the side of gas turbine generator 2 by using the steam for the amount of heat used for drying sludge for the improvement of power generation efficiency.

  The processing system 1 ′ according to the second embodiment is a system that maintains the gas turbine generator 2 at a constant output and generates steam with the heat of the carbonized exhaust gas H (in the form of steam) for recovery. Compared with a system that controls fluctuations in the sewage sludge treatment amount of the treatment system 1 with the load (power generation amount) of the turbine generator 2, the number of devices increases, but there are the following merits.

  ・ By performing the turbine chain cycle, power generation efficiency is increased by about 20%.

  -Power generation efficiency increases by about 10% due to a decrease in the intake air temperature when the turbine is introduced.

Regarding the balance of scale when combining sludge carbonization equipment (mainly carbonization (activation) furnace 3) and power generation equipment (mainly gas turbine generator 2), the amount of dewatered cake of sludge is 100 t / d. :
In the processing system 1 ′ according to the second embodiment, the gas turbine power generation amount of 400 to 1000 kW is in the proper range, while in the processing system 1 of the first embodiment, the gas turbine power generation amount of 200 to 500 kW is in the proper range. The reason for this is that the processing system 1 can be used to improve the power generation efficiency, whereas the use of the recovered heat is limited to drying sludge.

(Example 3)
FIG. 4 is a flowchart showing a processing system according to still another embodiment of the present invention. As shown in FIG. 4, the treatment system 1 ″ of this example generates methane gas from the first settling sludge generated at the sewage treatment plant and the collected food waste and uses it as fuel for the gas turbine generator 2 to produce sewage. This is a system for producing activated carbide by carbonizing surplus sludge from a treatment plant, which differs from the above two treatment systems 1 and 1 'in that it has a digestion tank 25, and this digestion tank 25 is used for initial sedimentation sludge. V and food waste Y are digested with microorganisms to generate digested gas M containing methane, which is used as fuel for gas turbine generator 2. On the other hand, digested sludge W is generated at this time, which is landfilled. Buried in the ground, etc. Methane gas M is used as fuel for the gas turbine generator 2 to generate electricity, while the turbine exhaust gas G discharged from the gas turbine generator 2 is supplied to the carbonization (activation) furnace 3 for surplus. While using for the carbonization of the excess sludge Z, the digester tank 25 is heated using the heat | fever collect | recovered via the heat exchanger 5, or it uses for the pretreatment (drying) of the excess sludge Z.

  The processing system 1 ″ of this example basically uses the processing system 1 of Example 1. Although not shown in FIG. 4, a dryer for drying the dewatered cake of excess sludge Z ( 1) and the heated air generated by recovering the heat of the exhaust gas H from the carbonization (activation) furnace 3 through the heat exchanger 5 is used in the dryer 4. Also, in the carbonization (activation) furnace 3 The activated carbide C to be produced is the same as in Examples 1 and 2 above, but is used as a dioxin adsorbent and a deodorizing agent outside the system system, and is used as a dewatering aid for excess sludge Z inside the system system. In this example, it can also be used as a biological carrier for adsorbing and holding microorganisms in the digestion tank 25.

  In addition, in the treatment systems 1 to 1 ″ of each of the above embodiments, dried organic waste such as sewage sludge can be used as auxiliary fuel J necessary for carbonization, whereby conventional fossil fuels such as heavy oil can be used. In addition to sewage sludge and food waste, as long as it contains carbon, various organic wastes can be made into carbides and used effectively.

It is a flowchart which shows the Example which applied the processing system of this invention to the process of the sewage sludge systematically. It is a schematic sectional drawing which shows an example of the carbonization (activation) furnace used for the processing system of this invention. It is a flowchart which shows another Example which applied the processing system of this invention to the process of sewage sludge systematically. It is a flowchart which shows the processing system which concerns on another Example of this invention.

Explanation of symbols

1, 1 ', 1 "treatment system 2 Gas turbine generator 3 Carbonization (activation) furnace 4 Dryer 5 Heat exchanger 6 Oil supply pipe 7 Auxiliary fuel injection amount adjustment valve 8 Feed pipe 9 Feed pump 10 Supply pipe 11 Flow rate Adjustment valve 12 Return pipe 13 Exhaust pipe 14 Temperature sensor 15 Oxygen concentration sensor 16 Branch circulation pipe 17 Circulation flow rate control valve 18 Furnace temperature sensor 19 Waste heat boiler 20 Water supply device 21 Cooler 22 Air temperature sensor 23 Fuel injection pump 24 Auxiliary fuel Injection pump 25 Digestion tank 27/29 Steam injection amount adjustment valve 31 Furnace body 32 Inlet 33 Carbonization pipe 34 Screw conveyor 36 Cooling pipe 37 Water cooling mechanism 38 Rotary valve S Dehydrated cake T Dry sludge G Turbine exhaust gas H Carbonized exhaust gas I Exhaust gas

Claims (7)

An organic waste treatment method in which a gas turbine generator is installed in a carbonization furnace, and power is supplied to the carbonization furnace and others, and a dehydrated cake of organic waste is dried and supplied to the carbonization furnace and carbonized. There,
The combustion exhaust gas discharged from the gas turbine is supplied to the carbonization furnace and burned with auxiliary fuel, and the dried dehydrated cake is pyrolyzed and carbonized in a reducing atmosphere to recover the carbide,
A method for treating organic waste, wherein the retained heat of the exhaust gas from the carbonization furnace is recovered through heat exchange means and used for drying the dehydrated cake. Water is heated by the exhaust gas of the carbonization furnace to generate steam, a part of the steam is introduced into the dehydrated cake, and the remaining part of the steam is introduced into the gas turbine to enter the chain cycle. The organic waste processing method according to claim 1, wherein the remainder is used for cooling air for cooling air introduced into the gas turbine. By recovering heat through the heat exchange means, heated air of 200 ° C. or higher or superheated steam is used for drying the dehydrated cake, and the temperature of the carbonization furnace is maintained at 900 ° C. or higher. The organic waste processing method according to claim 1 or 2, wherein the amount of power generated by the gas turbine is controlled so that the oxygen concentration of the exhaust gas that has passed through the heat exchange means is maintained at 9% or less after controlling the supply amount. . A system for treating organic waste in which a gas turbine generator is installed in a carbonization furnace, and the dehydration cake of organic waste is dried and supplied to the carbonization furnace and carbonized while supplying power to the carbonization furnace and others. There,
A heat exchanger for recovering the heat of the exhaust gas discharged from the carbonization furnace to generate superheated steam or heated air, and drying the dehydrated cake with the superheated steam or heated air supplied from the heat exchanger, An organic waste treatment system comprising a dryer for supplying to a carbonization furnace. A temperature sensor and an oxygen concentration sensor of the exhaust gas are respectively attached to the exhaust pipe of the exhaust gas discharged from the heat exchanger, and one end of the branch circulation pipe branched from the exhaust pipe is connected to the vicinity of the combustion exhaust gas inlet of the carbonization furnace In addition, a circulation flow rate control valve is provided in the branch circulation pipe, and the opening degree of the circulation flow rate control valve is automatically adjusted according to the temperature of the exhaust gas measured by the temperature sensor. The organic waste processing system according to claim 3, further comprising a fuel injection amount adjusting mechanism that controls the fuel injection amount in accordance with the fuel injection amount. A system for treating organic waste in which a gas turbine generator is installed in a carbonization furnace, and the dehydration cake of organic waste is dried and supplied to the carbonization furnace and carbonized while supplying power to the carbonization furnace and others. There,
A waste heat boiler for recovering heat of exhaust gas discharged from the carbonization furnace to generate superheated steam, a water supply device for supplying water to the waste heat boiler and the following cooler, and supply from the waste heat boiler A dryer for drying the dehydrated cake with superheated steam and supplying it to the carbonization furnace; and a cooler for cooling the air with superheated steam supplied from the waste heat boiler and introducing it into the gas turbine; And a supply path for supplying superheated steam from the waste heat boiler to the gas turbine. A temperature sensor and an oxygen concentration sensor of the exhaust gas are respectively attached to the exhaust pipe of the exhaust gas discharged from the heat exchanger, and one end of the branch circulation pipe branched from the exhaust pipe is connected to the vicinity of the combustion exhaust gas inlet of the carbonization furnace In addition, a circulation flow rate adjustment valve is provided in the branch circulation pipe, and the opening degree of the circulation flow rate adjustment valve is automatically adjusted according to the temperature of the exhaust gas measured by the temperature sensor, and the oxygen concentration sensor The auxiliary temperature sensor provided in the carbonization furnace is connected to a flow rate adjustment valve for adjusting the amount of auxiliary fuel supplied to the carbonization furnace, and the auxiliary fuel is changed according to changes in the temperature in the carbonization furnace and the oxygen concentration of the exhaust gas. The organic waste treatment system according to claim 6, wherein the supply amount can be controlled.

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