TW202309444A - Sludge incineration system and sludge incineration method - Google Patents

Abstract

A problem is to provide a sludge incineration system and a sludge incineration method in which a flow path of a heat exchanger is less likely to be clogged or eroded. The problem is solved by a sludge incineration system including circulating gas flowing in a circulation path, a dryer that dries a first dehydrated sludge with the heat of the circulating gas to obtain dried sludge, a separator that separates the dried sludge and the circulating gas, an air preheater that exchanges heat between the air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating the sludge to obtain preheated air, and a circulating gas heater that heats the circulating gas by heat exchange with the preheated air to obtain high-temperature circulating gas, the sludge incineration system being characterized in that the circulating gas is circulated by being discharged from the dryer together with the dried sludge, passing through the separator, reaching the circulating gas heater to be heated therein, and being resupplied to the dryer, and the dryer dries and pulverizes the first dehydrated sludge into powdery dry sludge. The problem is also solved by the corresponding sludge incineration method.

Description

Sludge incineration system and sludge incineration method

The sewage treatment method usually implemented in the sewage industry adopts the method of concentrating the sewage generated by people's lives or in the workplace into the sewer, and treating it with activated sludge in the sewage terminal treatment plant. In this method, since sewage sludge such as waste sludge and excess sludge is generated, incineration facilities are installed to treat this sewage sludge. In incineration facilities, sewage sludge is treated by various incineration systems and incineration methods.

Patent Document 1 discloses a technology related to a sludge incineration system. The problem to be solved is to suppress dry discharge caused by adhesion of tar in a supply means for supplying dry exhaust gas after removal means to other equipment The supply of gas is stagnant, and this removal means is a means of removing predetermined substances from gas generated during drying of sludge. Patent Document 1 discloses, as one element of its solution, a dryer that obtains its heat source from a drying heat exchanger, and the heat source is based on incineration exhaust gas generated in an incinerator.

[Prior Art Literature] (patent documents) Patent Document 1: Japanese Patent Laid-Open No. 2014-074538

[Problem to be solved by the invention] However, in the form of this heat exchanger, the incineration exhaust gas passes through the flow path in the heat exchanger, so dust and tar contained in the incineration exhaust gas cause problems. If dust and tar adhere to and accumulate in the flow path in the heat exchanger, clogging and corrosion may occur.

Therefore, the problem to be solved by the present invention is to provide a sludge incineration system and a sludge incineration method, which are less likely to cause blockage and erosion of the flow path of the heat exchanger.

[Technical means to solve the problem] One aspect of means for solving the above-mentioned problems is as follows. (first form) A sludge incineration system is a sludge incineration system for incinerating sludge, which is characterized in that it has: recycle gas, which circulates in the recycle path; a dryer for drying the first dewatered sludge by utilizing the heat of the aforementioned circulating gas to generate dried sludge; a separator, which separates the aforementioned dried sludge from the aforementioned circulating gas; an air preheater that exchanges heat between air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating the aforementioned sludge to generate preheated air; and, A circulating gas heater, which exchanges heat between the aforementioned circulating gas and the aforementioned preheated air to heat and generate high-temperature circulating gas; Wherein, the aforementioned circulating gas is discharged from the aforementioned dryer together with the aforementioned dried sludge, reaches the aforementioned circulating gas heater through the aforementioned separator, is heated, and is supplied to the aforementioned dryer again for circulation; The dryer pulverizes the first dewatered sludge while drying it, so that the dried sludge in the form of powder is produced.

In the conventional sludge incineration system disclosed in Patent Document 1, the circulating gas supplied to the dryer obtains its heat source by exchanging heat with the incineration exhaust gas. On the other hand, in an aspect of the present invention, the circulating gas obtains its heat source from the circulating gas heater. The circulating gas heater has a flow path for the circulation of clean (clean) preheated air and a flow path for the circulation of the circulating gas, and heat exchange is performed between these flow paths, and dust and tar will not flow into the supply The flow path through which air is preheated makes it less prone to clogging and erosion of the flow path due to dust and tar.

In addition, preheated air is supplied from the outside, and the heat source used for preheating is obtained from the air preheater through which the incineration exhaust gas circulates. Therefore, by adding a configuration that can increase or decrease the supply of external air, it can respond to sludge The operating conditions of the incineration system are used to flexibly adjust the temperature and flow of the circulating gas.

(second form) The sludge incineration system of the first aspect, wherein, the aforementioned dryer has: a pipe extending in an annular shape; a sludge introduction part for introducing the first dewatered sludge into the pipe; a gas supply part for supplying the high-temperature circulating gas into the pipe; and a gas discharge part for Discharging the aforementioned circulating gas containing the aforementioned dried sludge from the aforementioned pipe; And the said high-temperature circulating gas supplied from the said gas supply part circulates at high speed in the said pipe, and it is comprised so that it may collide with the said 1st dewatered sludge introduced from the said sludge introduction part.

As a treatment method of the 1st dewatered sludge, the method of reducing the water content to the density|concentration which can put into an incinerator is mentioned as an example, and thereafter incinerates it in an incinerator. The drying machine of this aspect circulates the high-temperature circulating gas in the pipe at high speed and continuously collides with the first dewatered sludge, so the first dewatered sludge is crushed and becomes powdery dry sludge, and the powdery dry sludge Sludge is included in the circulating gas and discharged together from the gas discharge part.

(third state) The sludge incineration system of the 1st aspect in which the said dry sludge produced|generated by the said dryer is sent to the said separator together with the said circulation gas.

Considering that there are various ways to transport the dried sludge to the incinerator, in this embodiment, the dried sludge is transported together with the circulating gas, so there is no need to install equipment and equipment for transporting the sludge separately, and the sludge can be dried easily. delivery.

(fourth aspect) The sludge incineration system of the first form has: A white smoke prevention preheater that exchanges heat between the intake gas supplied from the white smoke prevention fan and the aforementioned incineration exhaust gas that has passed through the aforementioned air preheater to generate high-temperature intake gas; and, An extraction gas heater, which exchanges heat between the extraction gas extracted from the aforementioned circulating gas and the aforementioned high-temperature intake gas to generate high-temperature extraction gas; In addition, the aforementioned extraction gas is obtained by extracting and dehumidifying the circulation path formed by connecting the aforementioned separator and the aforementioned circulating gas heater; The high-temperature extraction gas is supplied to an incinerator for incinerating the sludge.

Evacuation of a part of the cycle gas is procedurally necessary, but conventionally it has been accompanied by difficulties in its treatment (specifically, removal of odor and tar). In this form, the dehumidified exhaust gas is exchanged with high-temperature intake gas to generate high-temperature exhaust gas, thereby suppressing adhesion and solidification of tar toward the exhaust gas pipeline. Moreover, it is comprised so that an extraction gas may be supplied to an incinerator, and by this, reduction of the sludge odor in a circulation path can be aimed at.

(fifth form) The sludge incineration system of the first form has: an incinerator for incinerating the aforementioned sludge; and, A sludge feeding machine, which puts the aforementioned sludge into the aforementioned incinerator; And, the above-mentioned dry sludge separated by the above-mentioned separator is discharged to the above-mentioned sludge feeding machine; The said sludge input machine inject|throws the said dry sludge and the said 1st dewatered sludge into the said incinerator.

If only the first dewatered sludge is put into the incinerator, the sludge combustion in the furnace will become unstable depending on the moisture content and input amount of the first dewatered sludge. According to this aspect, since dried sludge is put into an incinerator in addition to the 1st dewatered sludge, the moisture content of the whole sludge to be incinerated will fall, and stabilization of sludge combustion will be aimed at.

(sixth aspect) In the sludge incineration system of the fifth aspect, the second dewatered sludge is further put into the aforementioned incinerator.

If the first dewatered sludge and the dried sludge are charged into the incinerator from a single input line, dust explosion may be caused in the furnace. In this aspect, since the second dewatered sludge is additionally charged into the incinerator, dust explosion can be suppressed.

(seventh form) The sludge incineration system of the first aspect includes an incinerator for incinerating the aforementioned sludge; In addition, a part of the preheated air is supplied to the incinerator through the circulating gas heater, and the remaining part is supplied to the incinerator without passing through the circulating gas heater.

The flow rate of the circulating gas flowing through the circulation path is changed according to the operating conditions of the incinerator and the sludge incineration facility including the incinerator. When the flow rate of the circulating gas is low, the circulating gas heater continuously circulates a certain amount of preheated air through the flow path, so-called dry burning state, which may cause wear and tear. According to this aspect, since the remaining part of the circulating gas does not flow into the circulating gas heater, the circulating gas heater is less likely to be in a dry state.

(eighth aspect) The sludge incineration system of the first aspect is provided with a control device which obtains a measured temperature by measuring the temperature of the circulating gas supplied to the dryer, and calculates a target of the circulating gas supplied to the dryer based on the measured temperature. temperature, and to control the increase and decrease of the flow rate of the air supplied from the outside so that the temperature of the circulating gas approaches the target temperature.

With the control device of this aspect, the temperature of the circulating gas supplied to the dryer is converged to a predetermined temperature, and it is difficult to cause initial wear of each device, and the running cost can be suppressed to be low.

(ninth form) The sludge incineration system of the 2nd aspect which does not introduce the said dried sludge into the said dryer.

When drying the first dewatered sludge, depending on the concentration of organic components and water content, it may not be easy to dry or it may take a long time to dry in the case of the previous dryer, so it is necessary to mix the dried sludge to the first The dewatered sludge is dried as a mixture. On the other hand, the inventors have found that in the dryer of the second aspect, even if the first dewatered sludge is not mixed with the first dewatered sludge, only the first dewatered sludge is introduced into the dryer alone, and it can be easily implemented. Dry and granulate. The mechanism is not yet clear, but it is considered to be caused by the continuous and high-speed impact of the high-temperature circulating gas on the first dewatered sludge to be processed.

(tenth aspect) A sludge incineration method is a sludge incineration method for incinerating sludge, which is characterized in that it has: a circulation step which circulates the circulation gas in the circulation path; a drying step of drying the first dewatered sludge in a dryer using the heat of the aforementioned circulating gas to generate dried sludge; a separation step, which separates the aforementioned dried sludge from the aforementioned circulating gas in a separator; A preheated air obtaining step of exchanging heat in an air preheater between air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating the aforementioned sludge to generate preheated air; and, A step of obtaining high-temperature circulating gas, which exchanges heat between the aforementioned circulating gas and the aforementioned preheated air in the circulating gas heater to heat and generate high-temperature circulating gas; Wherein, the aforementioned circulating gas is discharged together with the aforementioned dried sludge from the aforementioned dryer, reaches the aforementioned circulating gas heater through the aforementioned separator, is heated, and is supplied to the aforementioned dryer again for circulation; In the drying step, the first dewatered sludge is pulverized while being dried to produce the dried sludge in the form of powder.

The same effect as that of the first aspect can be expected.

[Effect of the invention] According to the present invention, it becomes a sludge incineration system and a sludge incineration method that are less likely to cause clogging and erosion of the flow path of the heat exchanger.

＜First Embodiment＞ Next, the mode for carrying out the invention will be described. In addition, the aspect of this embodiment is an example of this invention. The scope of the present invention is not limited to the scope of the form of this embodiment.

The sludge incineration system of this form is characterized in that it includes: a circulating gas that circulates in the circulating path (G1, G2, G3, G4, G5); a dryer 100 that uses the heat of the circulating gas to dry the first dehydrated sewage Sludge 5 is dried to generate dry sludge; separator 10, which separates the dried sludge from circulating gas; The gas is heat-exchanged to generate preheated air; and, the circulating gas heater 30 is used to exchange heat between the circulating gas and the aforementioned preheated air to heat and generate high-temperature circulating gas; wherein the aforementioned circulating gas is obtained from the aforementioned drying The dryer 100 is discharged together with the dried sludge, reaches the aforementioned circulating gas heater 30 through the aforementioned separator 10 to be heated, and is supplied to the aforementioned dryer 100 again for circulation; the aforementioned dryer 100, while treating the first dewatered sludge It is pulverized while being dried to produce powdery dry sludge. Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 .

In addition, the dampers V1 to V7 shown below each have an opening and closing function to increase or decrease the flow rate of gas or air flowing through the piping in which the respective dampers V1 to V7 are installed.

The first dewatered sludge 5 brought in from the outside of the system is fed into the quantitative feeder 80, and an appropriate amount of the first dewatered sludge 5 is circulated through the sludge pipe 6, introduced into the sludge feeder 19, and Put into the incinerator 20. Moreover, even if the sludge piping 6 is not provided especially, you may be comprised so that the 1st dewatered sludge may be directly introduced into the sludge feeding machine 19 (or the incinerator 20). The quantitative feeder 80 can be illustrated as having two discharge parts, the first discharge part is connected to the sludge pipe 6 extending toward the sludge feeding machine 19, and the second discharge part is connected to the sludge pipe 6 extending toward the feed hopper 90. Piping 7. From the quantitative feeder 80 , the first dewatered sludge 5 is individually introduced into the incinerator 20 and the dryer 100 . In addition, the first dewatered sludge 5 is not particularly limited. For example, it is formed by dehydrating a mixture of waste sludge and excess sludge generated in a sewage treatment plant, and has a water content of 40 to 85%.

It may also be constructed such that a flow sensor F1 is provided in the sludge piping 6 described in detail later to measure the flow rate of the first dewatered sludge circulating in the sludge piping 6, and the computing device 110 receives the flow sensor F1. Data on the measured value of F1.

The sludge input machine 19 is a device for inputting the sludge introduced into the sludge input machine 19 into the sludge input part 21 of the incinerator 20, for example, the sludge is transported by using a natural flow, a conveyor belt, a quantitative feeder, etc. to the sludge input part 21. As the sludge to be conveyed, the first dewatered sludge 5, dried sludge, and the like can be illustrated.

(Incinerator) The sludge conveyed by the sludge feeding machine 19 is thrown into the incinerator 20 from the sludge feeding part 21 . The incinerator 20 is a facility for incinerating the inputted sludge. The incinerator 20 is not particularly limited, and can be exemplified as a flow incinerator, a circulating flow incinerator, a stoker type incinerator, etc., and a turbocharged type flow incinerator is particularly preferable. Turbocharged flow incinerator, for example, sludge is supplied to a pressurized flow hearth and burned, and the turbocharger is rotated by the incineration exhaust gas discharged from the flow incinerator to generate compressed air, and the compressed air is compressed Air is supplied to the flow incinerator to facilitate combustion. Also, the fluid incinerator is an incinerator that fills the lower part of the furnace with solid particles such as flowing sand. The solid particles have a predetermined particle size as a fluid medium, and the flow is maintained by the combustion air supplied to the furnace. The sludge injected from the sludge input unit 21 and the auxiliary fuel supplied according to the need are burned while maintaining the flow state of the layer. In the lower part of the side wall, an auxiliary fuel combustion device (not shown) is arranged to heat the flowing sand with a particle size of about 400-600 μm filled in the fluid incinerator; at the position near the upper side of the auxiliary fuel combustion device, A start-up burner (not shown) is arranged to heat fluidized sand during start-up; and a sludge input part 21 is provided above the start-up burner. In addition, an air supply pipe 22 is provided below the fluidized incinerator to supply preheated air that imparts oxygen necessary for combustion and kinetic energy for maintaining the fluid state of the fluidized bed in the furnace. As the air supply pipe 22, a dispersing pipe and a dispersing plate can be used. The dispersing pipe is formed by arranging a plurality of pipes having a plurality of openings. become. Further, the high-temperature extraction gas that has passed through the extraction gas heater 70 may be supplied from the air supply pipe 22 into the furnace. At this time, for example, the high-temperature extraction gas is supplied into the furnace through the extraction gas piping G8 connecting the extraction gas heater 70 and the air supply pipe 22 . In addition, the incineration exhaust gas refers to a combustion gas generated when sludge is burned, or a gas composed of a mixture of combustion gas and water vapor.

(Air preheater) The incineration exhaust gas generated in the incinerator 20 is discharged from the incinerator 20 at 800 to 900° C., flows through the incineration exhaust gas piping 39 , and flows into the air preheater 40 . The incineration exhaust gas piping 39 is connected to the exhaust gas of the incinerator 20 Exhaust and air preheater 40. The air preheater 40 has a flow path through which incineration exhaust gas flows and a flow path through which air supplied from the outside flows, and indirectly performs heat exchange between the two flow paths. The method of heat exchange used as the air preheater 40 is not particularly limited, but is preferably a tube type, for example, a two-layer tube type, a shell-and-tube type, and a spiral type can be used. The air supplied from the outside is supplied with the outside air at room temperature or outside air temperature by the blower B2, so as to circulate through the air pipe A1 and flow into the air preheater 40. The air pipe A1 is connected to the blower B2 and the air preheater. The proximal end of the flow path through which air supplied from the outside in the device 40 flows. The air piping A1 may be provided with a damper V2 for adjusting the supply amount of air. The air supplied from the outside is preheated in the air preheater 40 to become preheated air at 80 to 700° C., flows out from the air preheater 40, flows through the air pipe A2, and flows into the circulating gas heater 30. The air pipe A2 The circulating gas heater 30 and the air preheater 40 are connected.

(white smoke prevention preheater) The combustion exhaust gas at 550-700°C discharged from the air preheater 40 flows through the combustion exhaust gas piping 49 and flows into the white smoke prevention preheater 50. The combustion exhaust gas piping 49 is connected to the white smoke prevention preheater 50 and Air preheater 40. The white smoke preventing preheater 50 prevents condensation and visualization of water vapor contained in the combustion exhaust gas generated during the diffusion of the combustion exhaust gas discharged from the chimney of the combustion processing facility in the atmosphere. The white smoke prevention preheater 50 is a heat exchanger having a flow path through which intake gas of air supplied from the outside flows into the white smoke prevention preheater 50 and a flow path through which combustion exhaust gas flows. It is formed by indirect heat exchange between flow paths. The method of heat exchange used as the white smoke prevention preheater 50 is not particularly limited, but is preferably a tube type, for example, a two-layer tube type, a shell-and-tube type, and a spiral type can be used. Intake air is circulated through the air pipe A7 by a fan (also referred to as "white smoke prevention fan B3") that sends outside air at room temperature or outside air temperature toward the white smoke prevention preheater 50. It flows into the white smoke prevention preheater 50 , and the air pipe A7 connects the white smoke prevention fan B3 and the base end of the flow path in the white smoke prevention preheater 50 through which the intake air flows. The intake gas passes through the white smoke prevention preheater 50 and exchanges heat with the incineration exhaust gas to obtain heat to become high-temperature intake gas of 200-400° C. and flows out from the white smoke prevention preheater 50 . The high-temperature intake gas flows into the extracted gas heater 70 through the air pipe A8 that connects the white smoke preventing preheater 50 and the extracted gas heater 70 .

On the other hand, the incineration exhaust gas passed through the white smoke prevention preheater 50 and cooled (cooled) to 200 to 600° C. flows through the incineration exhaust gas piping 59 and flows into the incineration exhaust gas treatment facility 120 .

(extraction gas heater) The high-temperature intake gas passing through the white smoke preventing preheater 50 flows into the extracted gas heater 70 through the air pipe A8 , and the air pipe A8 connects the extracted gas heater 70 and the white smoke preventing preheater 50 . The extraction gas heater 70 exchanges heat between the extraction gas drawn from the circulation path and the high-temperature intake gas to obtain high-temperature extraction gas. A damper V6 can be provided to adjust the flow rate of the high-temperature intake air flowing through the air pipe A8 to the extraction gas heater 70 . The extraction gas heater 70 has a flow path through which the high-temperature intake gas flows and a flow path through which the extraction gas flows, and heat is exchanged indirectly between the two flow paths. In addition, the pumping gas is a part of the circulating gas and is drawn from the circulating path.

The circulating gas flowing through the circulating path contains tar and odor, and part of the circulating gas may be pumped for the purpose of removing the tar and odor. The extracted gas is guided toward the incinerator 20 and incinerated, so it is preferable to incinerate the extracted gas with reduced water content (that is, the dehumidified extracted gas). In addition, the extraction gas is preferably heated after the extraction gas heater 70 exchanges heat with the high-temperature intake air, so it may also be in the circulation path from the separator 10 to the circulation gas heater. The range between 30 is pumped. If the circulating gas in this section can be pumped, the advantage is that the pumping gas is suitable for removing dry sludge and relatively low temperature.

The extraction gas extracted from the circulation path flows into the extraction gas heater 70 through the extraction gas pipes G6 and G7 connecting the extraction gas heater 70 and the circulation path. The extracted gas flowing toward the extracted gas heater 70 is preferably dehumidified, so for example, the condenser 60 may be interposed between the extracted gas pipes G6 and G7 to dehumidify the extracted gas.

The high-temperature extraction gas flows out from the extraction gas heater 70, flows through the extraction gas piping G8 extending from the extraction gas heater 70 to the incinerator 20, and is sent to the incinerator 20 to be used as air fuel together with the sludge incinerate. If the temperature of the high-temperature extraction gas flowing out from the extraction gas heater 70 is low, the tar contained in the extraction gas may liquefy and stick to the piping to cause blockage, so the temperature of the extraction gas is preferably at 350 ℃ or more. Liquefaction of tar can be suppressed by increasing the temperature of the exhaust gas. In addition, the tar and odor of the exhaust gas will cause adverse effects on various equipment, but these adverse effects can be eliminated as much as possible by incineration.

The high-temperature intake gas circulates in the flow path for the high-temperature intake gas and its heat is taken away by the extraction gas, flows out from the extraction gas heater 70 at 150-500°C, flows through the air pipe A9 and is guided toward the chimney 130, the air pipe A9 connects the extraction gas heater 70 and the chimney 130.

When the inflow amount of the extraction gas is small, if the high-temperature intake gas continues to flow into the extraction gas heater 70, it will be overheated and a so-called dry burning state will occur. To avoid this state, bypass air piping A10 for evacuating high-temperature intake gas from air piping A8 toward air piping A9 and a damper V7 provided on bypass air piping A10 can be provided. The bypass air piping A10 may be provided on the upstream side of the damper V6 in the air piping A8. By installing the bypass air pipe A10, a sufficient amount of intake air flowing to the white smoke prevention preheater 50 is ensured, and part of the high-temperature intake air is withdrawn to the air pipe A9 while the remaining part is directed toward the exhaust air. Gas gas heater 70 supply. In this way, the flow rate of the high-temperature intake gas flowing into the extraction gas heater 70 can be adjusted in accordance with the flow rate of the extraction gas flowing into the extraction gas heater 70 .

In addition, evacuation refers to extracting a part of the circulation gas flowing through the circulation path.

(circulating gas heater) The preheated air that has been preheated in the air preheater 40 through heat exchange with the incineration exhaust gas flows out of the air preheater 40 and circulates through the air pipes A2 and A3 at 200-700°C and flows into the circulating gas for heating 30, the air pipes A2, A3 are connected to the circulating gas heater 30 and the air preheater 40. The circulating gas heater 30 has a flow path through which the circulating gas flows and a flow path through which the preheated air flows, and heat is exchanged indirectly between the two flow paths. The way of heat exchange used as the circulating gas heater 30 is not particularly limited, and it is preferably a tube type, for example, a two-layer tube type, a shell-and-tube type, a spiral heat exchanger can be used, and a shell-and-tube heat exchanger is also used. is better. When a shell-and-tube heat exchanger is used, it is preferable that the circulating gas containing dust circulates in the heat pipes where the dust is not easy to accumulate, and the preheated air circulates in the shell. In addition, the air piping A2 and the air piping A3 are integrally connected and constituted so that preheated air continuously flows between the two pipings.

It is also possible to install the damper V1 on the air piping A2, A3. The flow rate of the preheated air can be increased or decreased by the opening and closing operation of the damper V1, and the heat obtained by the circulating gas heater 30 can be adjusted, and the temperature management of the circulating gas can be performed.

Moreover, the air piping A4 branched from the air piping A2 and A3 can be provided so that the preheated air can flow through the air supply pipe 22 of the incinerator 20 . The branching place may be provided on the upstream side of the installation position of the damper V1 in the air pipes A2 and A3. Furthermore, a damper V3 can be provided in the air pipe A4 to adjust the flow rate of preheated air. With this configuration, part of the preheated air passes through the circulating gas heater and is supplied to the aforementioned incinerator, and the remainder of the air is not passed through the circulating gas heater and is supplied to the aforementioned incinerator.

The preheated air flowing out from the circulating gas heater 30 flows into the incinerator 20 through the air pipe A5, and the air pipe A5 is connected to the incinerator 20 (the air supply pipe 22 when the air supply pipe 22 is provided) and the circulation air pipe A5. Gas heater 30.

The circulating gas heater 30 of this embodiment has a flow path through which preheated air of clean air flows and a flow path through which circulating gas flows, and heat exchange is performed indirectly between these flow paths. The preheated air is obtained by preheating the air supplied from the outside of the sludge incineration system, so it is clean without dust and tar. Therefore, dust and tar do not flow into the flow path through which the preheated air flows, so that clogging, erosion, etc. of the flow path due to dust and tar are less likely to occur.

(loop path) The circulation path (G1, G2, G3, G4, G5) is a flow path for circulating gas, and has a flow path G4 connecting the dryer 100 and the separator 10, and a flow path connecting the separator 10 and the circulating gas heater 30 (G5, G1, G2), and the flow path G3 connecting the circulating gas heater 30 and the dryer 100. A blower B1 can be installed in the circulation path to circulate the circulation gas. As the place where the blower B1 is installed, it is preferable to use a flow path where the circulating gas is not high temperature and contains as little dry sludge as possible, for example, the flow path (G5, G1, G2) connecting the separator 10 and the circulating gas heater 30 is preferable. In addition, the flow path G5, the flow path G1, and the flow path G2 are individually connected so that the circulation gas can flow.

The flow rate of the circulating gas may be partially reduced by pumping, and external air may be introduced to make up for the reduced portion. For example, the external air introduction pipe G9 is connected to the upstream side of the location where the blower B1 is installed in the flow paths (G5, G1, G2), and the external air is introduced into the circulation path through the external air introduction pipe G9.

The extraction gas piping G6 can be installed in the flow paths (G5, G1, G2) so that the extracted extraction gas flows toward the extraction gas heater 70. The connection place of the gas pipe G6 is not particularly limited, and may be connected upstream of the external air introduction pipe G9 or may be connected downstream of the blower B1.

A damper V5 can be installed on the extraction gas piping G6. It is preferable to open and close the damper V5 to adjust the flow rate of the extraction gas corresponding to the flow rate of the high-temperature intake gas flowing through the extraction gas heater 70 .

(cycle gas) The specific flow of the cycle gas will be described below. In addition, the temperature of the circulating gas shown below is an example. The external air introduced from the external air introduction pipe G9 flows through the flow paths (G5, G1, G2) as circulating gas, is heated by the circulating gas heater 30, and flows out from the circulating gas heater 30 at 300-500°C. The circulating gas (high-temperature circulating gas) that has flowed out flows through the flow path G3 and flows into the dryer 100 .

The circulation gas containing the dried sludge generated in the dryer 100 flows out from the dryer 100 at 100 to 400° C., flows out in the flow path G4 , and flows into the separator 10 .

The circulating gas that has flowed into the separator 10 is separated from the dried sludge in the separator 10, and the remaining part flows out at 100 to 400°C, reaches the flow paths (G5, G1, G2) again, and circulates.

The flow rate of the circulating gas can be adjusted by the blower B1 provided in the circulation path, and it is sufficient to circulate at least at a flow rate that does not accumulate dry sludge on the circulation path.

A damper V4 can be provided in the flow path G2 to adjust the flow rate of the circulating gas.

(dryer) The dryer 100 contacts the first dewatered sludge fed from the feed hopper 90 with the high-temperature circulating gas flowing in from the circulation path, and pulverizes the first dewatered sludge while drying it, so as to produce dry sludge in the form of powder. sludge.

Examples of the dryer 100 include: (1) spray dryers, airflow dryers, fluidized bed dryers, rotary dryers, etc., in which the first dewatered sludge is dispersed and dried in a high-temperature circulating gas. (2) breathable belt dryer, tunnel dryer (co-current belt dryer), spray dryer, etc., directly transfer the first dewatered sludge in a static state, and in In the transfer process, the high-temperature circulating gas is brought into contact with the first dewatered sludge and dried; and (3) a stirring dryer, etc., such that the high-temperature circulating gas is brought into contact with the first dewatered sludge while mechanically stirring the first dewatered sludge. The first form of dewatered sludge and dried.

There are various kinds of the above-mentioned airflow dryer, and it is also possible to use an airflow dryer without a pulverizer, and it is possible to use the first dewatered sludge that has not been pulverized.

As the dryer 100 in FIGS. 1 and 2, it is shown as an airflow dryer. This air flow dryer is equipped with: a pipe 100B extending in a circular shape; a sludge introduction part 100E which introduces the first dewatered sludge into the pipe 100B; a gas supply part 100A which supplies high-temperature circulating gas to the pipe 100B; and, the gas discharge part 100F, which discharges the circulating gas containing dried sludge from the aforementioned pipe 100B; wherein, the high-temperature circulating gas supplied from the aforementioned gas supply part 100A circulates at a high speed in the aforementioned pipe 100B , and collides with the first dewatered sludge introduced from the sludge introduction part 100E. This pipe 100B is composed of a pipe portion 100Ba extending horizontally connected to the gas supply unit 100A, a pipe portion 100Bb bent upward from the pipe portion 100Ba and extending from the pipe portion 100Bb, and a pipe portion 100Bb from the pipe portion 100Bb in a turning direction (parallel to the pipe portion 100Ba). direction) and a pipe portion 100Bc that bends and extends downward, and a pipe portion 100Bd that bends and extends downward from the pipe portion 100Bc. Also, the pipe portion 100Bd is provided with a front end portion 100C joined to the front end portion 100D of the gas supply portion 100A so as to receive supply of high-temperature circulating gas flowing through the gas supply portion 100A. Moreover, although the sludge introduction part 100E and the gas discharge part 100F are separately provided in the pipe 100B, it is especially preferable that this sludge introduction part 100E is provided in the pipe part 100Ba.

The high-temperature circulating gas is supplied to the gas supply unit 100A through the flow path G3. The first dewatered sludge introduced into the pipe 100B from the sludge introduction part 100E through the sludge pipe 4 is introduced into the high-temperature circulating gas circulating in the pipe part 100Ba, continuously collides with the high-temperature circulating gas, and passes through the pipe 100B. The inside is blown away, dispersed and dried, and becomes powdery dry sludge. At this time, the larger sludge particles of the first dewatered sludge are split into a plurality of smaller sludge particles by colliding with the high-temperature and high-speed circulating gas, and the moisture contained therein evaporates rapidly.

Powdery sludge particles that have been dispersed and dried to a particle size below a certain level are discharged from the gas discharge unit 100F to the outside of the airflow dryer as dry sludge while being included in the circulating gas that circulates. On the other hand, relatively large sludge particles that are not sufficiently dispersed and dried are not discharged from the gas discharge unit 100F, but are repeatedly circulated in the pipe 100B until they are sufficiently dispersed and dried. Therefore, the airflow dryer mainly discharges the powdery dry sludge that has been fully dispersed and dried. Specifically, the high-temperature circulating gas is supplied from the gas supply unit 100A to the pipe 100B, and circulates through the pipe portion 100Ba, the pipe portion 100Bb, the pipe portion 100Bc, the pipe portion 100Bd, and the pipe portion 100Ba together with the sludge particles. One side is discharged toward the outside of the dryer 100 from the gas discharge part 100F. On the other hand, the high-temperature circulating gas that has not been exhausted merges and mixes with the high-temperature circulating gas newly sent from the gas supply unit 100A, and flows through the pipe portion 100Ba, the pipe portion 100Bb, the pipe portion 100Bc, and the pipe portion 100Bd. A part is discharged toward the outside of the dryer 100 from the gas discharge part 100F. As described above, part of the high-temperature circulating gas is discharged from the gas discharge unit 100F, and the remaining part of the high-temperature circulating gas circulates in the pipe 100B. In this way, the first dewatered sludge newly introduced and the first dewatered sludge circulated in the pipe 100B are mixed in the pipe and circulated to be dried and pulverized.

During the operation of the gas dryer, it is preferable that the flow velocity of the high-temperature circulating gas flowing through the gas supply part 100A of the airflow dryer be set to 20 m/s or more and 60 m/s or less, and the flow velocity in the pipe 100B be set to 15 m/s. /s or more and 45m/s or less. When the flow velocity in the gas supply part 100A and the pipe 100B is lower than the above-mentioned value, the sludge particles are not easy to circulate in the air flow dryer, and may hinder drying treatment or discharge to the outside of the circulator. Moreover, it is more preferable to set the flow velocity in the said pipe 100B to 15 m/s or more so that sludge particle|grains may circulate smoothly.

It is particularly preferable to set the flow velocity in the gas supply part 100A to be faster than the flow velocity in the tube 100B. Since there is a speed difference, the circulating sludge continuously collides with the newly supplied high-temperature circulating gas, so that the dispersion of sludge particles can be promoted.

Moreover, it may be high temperature circulating gas which circulates in the dryer 100, Preferably it is 300-500 degreeC, More preferably, it is 350-450 degreeC, More preferably, it is 400 degreeC. If the temperature of the high-temperature circulating gas is lower than this range, it will take a lot of time to dry. On the other hand, setting the temperature higher than this range has few advantages, and conversely, a large amount of energy is required to set the temperature to a high temperature, which has the disadvantage of lowering the cost performance of facility operation.

Also, in addition to the air flow dryer shown above, using an air flow dryer with a pulverizer as a dryer can also obtain the same effect as the above-mentioned air flow dryer, but the capacity of the auxiliary equipment will become larger and become Regular maintenance and exchange of shredders are required.

The heat of the circulation gas containing the dried sludge flowing out of the dryer 100 is deprived by drying of the first dewatered sludge in the dryer 100, and the temperature is 100 to 400°C. The dried sludge generated in the dryer 100 is sent to the separator 10. For example, if it is sent to the separator 10 together with the circulating gas, it is not necessary to have a separate device for sending it, so it is more preferable. The circulating gas including the dried sludge is supplied to the separator 10 through the flow path G4 connecting the gas discharge part 100F of the dryer 100 and the inflow part of the circulating gas in the separator 10 .

The dried sludge discharged from the dryer 100 has a water content of 1 to 40%.

(Splitter) The separator 10 performs gas-solid separation of the circulating gas containing dried sludge supplied from the flow path G4, removes the dried sludge, and discharges the remainder to the flow path G5. The separator 10 is provided with: a sludge supply part which receives the supply of circulating gas containing dried sludge; a sludge discharge part 11 which discharges the separated dry sludge; and a gas discharge part which discharges the circulating gas The remaining part of the dried sludge after being separated is discharged to the flow path G5. The separated dry sludge is discharged from the separator 10, for example, to the sludge feeding machine 19. The separated dry sludge can also freely fall from the sludge discharge part 11 and be supplied to the sludge feeding machine 19; it is also possible to provide a sludge piping 3 and supply it to the sludge feeding machine 19 through the sludge piping 3, The sludge piping 3 connects the sludge discharge unit 11 and the sludge charging machine 19 .

Examples of the separator 10 include: a gravity settling chamber that collects dust by gravity, a mist separator that collects dust by inertia, a cyclone separator that collects dust by centrifugal force, and a cyclone separator that collects dust by centrifugal force. Venturi scrubber for dust collection by net, bag filter for dust collection by filter cloth, mobile particle layer air filter for dust collection by filling layer, dust collection by electricity Electrostatic dust collector, etc.

The separator 10 can be installed directly above the sludge input machine 19 to discharge the separated dry sludge from the sludge discharge part 11 of the separator 10 to the aforementioned sludge input machine 19 . Dried sludge is light in weight and has a strong sludge odor, so if it is transported over a long distance, it will scatter and cause the sludge odor to float around. Therefore, if the dried sludge is discharged from the sludge discharge part 11 of the separator 10 to the sludge input machine directly below, it can be quickly thrown into the incinerator, so it is possible to suppress the scattering of the dried sludge and other problems as much as possible. Emanation of bad smell.

(first dewatered sludge) The first dewatered sludge 5 is temporarily stored in the quantitative feeder 80, and an appropriate amount is circulated through the sludge pipe 7, which flows into and stored in the feed hopper 90, and the sludge pipe 7 is connected to the feed hopper 90 and the quantitative feeder 80. . The sludge stored in the feed hopper 90 flows through the sludge pipe 4 , and is introduced toward the dryer 100 . The sludge pipe 4 connects the sludge introduction part 100E of the dryer 100 and the feed hopper 90 .

The feed hopper 90 may also receive the dried sludge separated by the separator 10 in addition to the first dewatered sludge. The dried sludge separated by the separator 10 can also be manually transported and dropped into the feed hopper 90; the sludge piping 9 can also be set so that the sludge can be circulated in the sludge piping 9 and dropped into the feed hopper 90, and the sludge piping can 9 connects the feed hopper 90 and the separator 10. Thereby, the first dewatered sludge and the dried sludge are mixed in the feed hopper 90 . Depending on the organic component concentration and water content, the first dewatered sludge may not be easily dried or may take a long time until it is dried. By introducing the mixture of the first dewatered sludge and the dried sludge into the dryer 100, the mixture can be dried and easily crushed.

(control) In order to control the operation of the sludge incineration system of this embodiment, a control device can be provided, and the computing device 110 is used for this control device. In order to implement this control, temperature sensors and flow sensors are installed in various parts of the sludge incineration system. The details are described below.

For the temperature sensor, as an example, a temperature sensor T1 for measuring the temperature of the incineration exhaust gas flowing through the incineration exhaust gas piping 39, a temperature sensor T2 for measuring the temperature inside the incinerator 20, and The temperature sensor T3 for measuring the temperature of the circulating gas flowing in the flow path G1 and G2, the temperature sensor T4 for measuring the temperature of the circulating gas flowing in the flow path G4, and the temperature sensor T4 for measuring the temperature of the circulating gas flowing in the flow path G3 Temperature sensor T5.

For the flow sensor, as an example, it is possible to individually install: a flow sensor F1 for measuring the flow rate of the first dewatered sludge flowing through the sludge piping 6 described later, and a flow sensor F1 for measuring the flow rate of the first dewatered sludge flowing through the sludge piping 7 . The flow sensor F2 of the flow rate, and the flow sensor F3 of measuring the flow rate of the circulating gas flowing in the flow paths G1 and G2.

The temperature data measured individually by the temperature sensors T1 - T5 and the flow rate data individually measured by the flow sensors F1 - F3 are transmitted to the computing device 110 in a wired or wireless manner. The arithmetic unit 110 calculates the output values of the individual openings of the dampers V1 to V7 based on the received input values of the data of the measured temperature and the data of the measured flow rate, using a prepared arithmetic formula. The computing device 110 sends the output value to the dampers V1 to V7. The dampers V1 to V7 operate individually provided actuators to change the flow rate by opening or closing the valves so that the opening degree so far becomes the received output value. The calculation formula is not particularly limited, and can be based on past measured temperature data, flow rate data, and opening data, such as least squares control, PI (proportional-integral) control, PID (proportional-integral-derivative) control, Neural network control, and manual input methods to build.

As a control device, for example, it can measure the temperature of the circulating gas supplied to the dryer 100 to obtain the measured temperature, calculate the target temperature of the circulating gas supplied to the dryer 100 based on the measured temperature, and set the temperature of the circulating gas to The increase and decrease of the flow rate of the air supplied from the outside are controlled so as to approach the target temperature. Here, the control of the increase or decrease of the flow rate of the air supplied from the outside means, for example, when the sludge incineration system is operated with the damper V2 at a specific opening degree (actual opening degree), the above-mentioned measured temperature is used as an input. value, input the preliminary calculation formula and obtain the target opening of the damper V2 as the output value, and make the actual opening of the damper V2 close to the obtained target opening as the output value, thereby implementing the air supplied from the outside Control of flow increase or decrease. By this control, the flow rate of the preheated air to flow into the circulating gas heater 30 is increased or decreased, and the temperature of the circulating gas subjected to heat exchange is raised or lowered.

Also, as another control device, for example, it is possible to measure the flow rate of the circulating gas flowing through the flow path G2 to obtain the measured flow rate, calculate the target flow rate of the circulating gas flowing through the flow path G2 based on the measured flow rate, and make the aforementioned cycle The flow rate of the gas is close to the target flow rate, thereby controlling the increase and decrease of the flow rate of the circulating gas. Here, the control of the increase and decrease of the flow rate of the circulating gas means, for example, that when the sludge incineration system is operated with the damper V5 at a specific opening (actual opening), the above-mentioned measured flow rate is used as an input value to input Prepare the calculation formula and obtain the target opening degree of the damper V5 as the output value, and make the actual opening degree of the damper V5 close to the obtained target opening degree as the output value, so as to control the increase and decrease of the flow rate of the circulating gas . By this control, the flow rate of the circulating gas passing through the circulating gas heater 30 is increased or decreased, and the temperature of the circulating gas flowing into the dryer 100 is raised or lowered.

Furthermore, as the control device in the quantitative feeder 80, it is possible to calculate the flow rate toward the dryer 100 based on the temperature data measured individually by the temperature sensors T1-T5 and the flow rate data measured individually by the flow sensors F1-F3. The target introduction amount of the first dewatered sludge and the target input amount of the first dewatered sludge to the incinerator 20 are controlled, and the discharge amount of the dewatered sludge is controlled to be the target introduction amount and the target input amount.

<Second Embodiment> The embodiment of the present invention has been described above, and it is also preferable to use this embodiment as the basis and add the following features as the sludge incineration system of the second embodiment shown in FIG. 3 . Specifically, it does not include The characteristics of drying sludge into the aforementioned dryer. Fig. 3 is a system diagram of the sludge piping 9 not provided in Fig. 1 . In the conventional dryer, the dried sludge is introduced together with the first dewatered sludge, but the characteristic dryer of this embodiment is configured so that even if the dried sludge is not actively introduced, the high-temperature circulating gas can flow through the dryer. Internal circulation to make the first dewatered sludge easy to dry. Therefore, there is no need to provide piping for guiding the dried sludge to the dryer, and there is an advantage that the overall form of the sludge incineration system is compact.

<Third Embodiment> Moreover, the sludge incineration system of the 3rd embodiment shown in FIG. 4 is also preferable. Specifically, the incinerator 20 included in this sludge incineration system further incinerates sludge, and the second dewatered sludge is further introduced into the incinerator 20 in addition to the first dewatered sludge.

The second dewatered sludge 1 imported from outside the system is put into the sludge feed hopper 140 . The sludge discharge part is provided in the sludge feed hopper 140, and the sludge discharge part and the sludge charging machine 19 are connected by the sludge piping 2. The second dewatered sludge 1 discharged from the sludge discharge unit flows into the sludge feeding machine 19 through the sludge pipe 2 .

In this aspect, the first dewatered sludge 5 , the second dewatered sludge, and the dried sludge can be illustrated as the sludge conveyed by the sludge feeding machine 19 . Both the second dewatered sludge 1 and the first dewatered sludge 5 are dewatered sludge, and are charged into the incinerator 20 individually. The entire amount of the second dewatered sludge 1 is thrown into the incinerator 20 . In the incineration of only the first dewatered sludge 5, depending on the nature and state, organic component concentration, and moisture content of the first dewatered sludge 5, spontaneous combustion in the incinerator 20 may be unstable, except for dried sludge In addition, by introducing the second dewatered sludge 1, the incinerator 20 continues to perform stable combustion.

Based on the 1st - 3rd embodiment shown above, the form of the sludge incineration system of the following aspect is also preferable. For example, a sludge incineration system may be provided with a white smoke prevention preheater 50 for exchanging heat between the intake gas supplied by the white smoke prevention fan B3 and the incineration exhaust gas that has passed through the air preheater 40 , to generate high-temperature intake gas; and, an extraction gas heater 70, which exchanges heat between the extraction gas extracted from the circulating gas and the high-temperature intake gas to generate high-temperature extraction gas. The aforementioned extraction gas is obtained by extracting and dehumidifying the circulation path (G5, G1, G2) connected to the aforementioned separator 10 and the circulating gas heater 30; wherein, the aforementioned high-temperature extraction gas is supplied to the incineration sludge The incinerator 20. Such a sludge incineration system is preferable because it can suppress the adhesion and solidification of tar toward the exhaust gas piping. Moreover, it is comprised so that the extraction gas may be supplied to the incinerator 20, and by this, the reduction of the sludge odor in a circulation path can be aimed at.

Moreover, as a sludge incineration method implemented using the embodiment shown above, the following can be illustrated. The sludge incineration method for incinerating sludge is characterized in that it has: (1) A circulation step that circulates the circulation gas in the circulation paths (G1, G2, G3, G4, G5); (2) a drying step, which uses the heat of the circulating gas in the dryer 100 to dry the first dewatered sludge 5 to generate dried sludge; (3) a separation step, which separates the dried sludge from the circulating gas in the separator 10; (4) A preheated air obtaining step of performing heat exchange in the air preheater 40 with air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating sludge to generate preheated air; and, (5) High-temperature circulating gas acquisition step, which performs heat exchange between the circulating gas and the aforementioned preheated air in the circulating gas heater 30 to heat and generate high-temperature circulating gas; Wherein, the aforementioned circulating gas is discharged from the aforementioned dryer 100 together with the dried sludge, reaches the aforementioned circulating gas heater 30 through the aforementioned separator 10 to be heated, and is supplied to the aforementioned dryer 100 again for circulation; the aforementioned drying step , pulverizing the first dewatered sludge while drying to generate powdery dried sludge.

(other) Granular dry sludge is difficult to define strictly, but for example, when air at a flow velocity of 20 m/sec flows through piping, it is dry sludge having a size that smoothly flows along with the flow of the air. For the main lines described in the figure, they are individually indicated as: the piping for circulating gas and extraction gas indicated by solid lines, the piping for incineration exhaust gas indicated by thick solid lines, and the piping indicated by chain lines for supply Piping for the circulation of the first dewatered sludge, dried sludge, and second dewatered sludge, piping for the circulation of externally supplied air, preheated air, intake air, and high-temperature intake air indicated by dotted lines, and pipes indicated by dotted lines The transmission and reception network of the temperature sensor, flow sensor, damper and calculation device shown.

[industrial availability] The invention can be used as a sludge incineration system and a sludge incineration method.

1: The second dewatered sludge 2,3,4,6,7,9: Sludge piping 5: The first dewatered sludge 10: Separator 11: Sludge discharge part 19: Sludge input machine 20: Incinerator 21: Sludge Input Department 22: Air supply pipe 30:Circulating gas heater 39, 49, 59: Incineration exhaust gas piping 40: Air preheater 50: White smoke prevention preheater 60: condenser 70: Extraction gas heater 80: Quantitative feeder 90: Feed hopper 100: Dryer 100A: Gas supply part 100B: tube 100Ba, 100Bb, 100Bc, 100Bd: tube part 100C: front end 100D: the front end of the gas supply part 100E: Sludge introduction department 100F: Gas discharge part 110: computing device 120: Processing equipment 130: chimney 140: sludge feed hopper A1, A2, A3, A4, A5, A7, A8, A9: Air piping A10: Bypass air piping B1, B2: blower B3: Fan for preventing white smoke F1, F2, F3: flow sensor G1, G2, G3, G4, G5: circulation path (flow path) G6, G7, G8: Extraction gas piping G9: Outer air introduction tube T1, T2, T3, T4, T5: temperature sensor V1, V2, V3, V4, V5, V6, V7: Throttle

Fig. 1 is a diagram showing an embodiment of the present invention. Fig. 2 is a diagram showing details of the dryer. Fig. 3 is a diagram showing an embodiment of the present invention. Fig. 4 is a diagram showing an embodiment of the present invention.

Domestic deposit information (please note in order of depositor, date, and number) none

Overseas storage information (please note in order of storage country, organization, date, and number) none

1: The second dewatered sludge

2,3,4,6,7,9: Sludge piping

5: The first dewatered sludge

10: Separator

11: Sludge discharge part

19: Sludge input machine

20: Incinerator

21: Sludge Input Department

22: Air supply pipe

30:Circulating gas heater

39, 49, 59: Incineration exhaust gas piping

40: Air preheater

50: White smoke prevention preheater

60: condenser

70: Extraction gas heater

80: Quantitative feeder

90: Feed hopper

100: Dryer

110: computing device

120: Processing equipment

130: chimney

140: sludge feed hopper

A1, A2, A3, A4, A5, A7, A8, A9: Air piping

A10: Bypass air piping

B1, B2: blower

B3: Fan for preventing white smoke

F1, F2, F3: flow sensor

G1, G2, G3, G4, G5: circulation path (flow path)

G6, G7, G8: Extraction gas piping

G9: Outer air introduction pipe

T1, T2, T3, T4, T5: temperature sensor

V1, V2, V3, V4, V5, V6, V7: Throttle

Claims (10)

A sludge incineration system is a sludge incineration system for incinerating sludge, which is characterized in that it has: recycle gas, which circulates in the recycle path; a dryer for drying the first dewatered sludge by utilizing the heat of the aforementioned circulating gas to generate dried sludge; a separator, which separates the aforementioned dried sludge from the aforementioned circulating gas; an air preheater that exchanges heat between air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating the aforementioned sludge to generate preheated air; and, A circulating gas heater, which exchanges heat between the aforementioned circulating gas and the aforementioned preheated air to heat and generate high-temperature circulating gas; Wherein, the aforementioned circulating gas is discharged from the aforementioned dryer together with the aforementioned dried sludge, reaches the aforementioned circulating gas heater through the aforementioned separator, is heated, and is supplied to the aforementioned dryer again for circulation; The dryer pulverizes the first dewatered sludge while drying it, so that the dried sludge in the form of powder is produced. The sludge incineration system as described in claim 1, wherein the aforementioned dryer has: a pipe extending in an annular shape; a sludge introduction part for introducing the first dewatered sludge into the pipe; a gas supply part for supplying the high-temperature circulating gas into the pipe; and a gas discharge part for Discharging the aforementioned circulating gas containing the aforementioned dried sludge from the aforementioned pipe; And the said high-temperature circulating gas supplied from the said gas supply part circulates at high speed in the said pipe, and it is comprised so that it may collide with the said 1st dewatered sludge introduced from the said sludge introduction part. The sludge incineration system according to claim 1, wherein the dried sludge generated in the dryer is sent to the separator together with the circulating gas. The sludge incineration system as described in claim 1 has: A white smoke prevention preheater that exchanges heat between the intake gas supplied from the white smoke prevention fan and the aforementioned incineration exhaust gas that has passed through the aforementioned air preheater to generate high-temperature intake gas; and, An extraction gas heater, which exchanges heat between the extraction gas extracted from the aforementioned circulating gas and the aforementioned high-temperature intake gas to generate high-temperature extraction gas; In addition, the aforementioned extraction gas is obtained by extracting and dehumidifying the circulation path formed by connecting the aforementioned separator and the aforementioned circulating gas heater; The high-temperature extraction gas is supplied to an incinerator for incinerating the sludge. The sludge incineration system as described in claim 1 has: an incinerator for incinerating the aforementioned sludge; and, A sludge feeding machine, which puts the aforementioned sludge into the aforementioned incinerator; And, the above-mentioned dry sludge separated by the above-mentioned separator is discharged to the above-mentioned sludge feeding machine; The said sludge input machine inject|throws the said dry sludge and the said 1st dewatered sludge into the said incinerator. The sludge incineration system according to Claim 5, wherein the second dewatered sludge is further put into the aforementioned incinerator. The sludge incineration system as described in Claim 1 is equipped with an incinerator for incinerating the aforementioned sludge; In addition, a part of the preheated air is supplied to the incinerator through the circulating gas heater, and the remaining part is supplied to the incinerator without passing through the circulating gas heater. The sludge incineration system according to claim 1, which has a control device that measures the temperature of the circulating gas supplied to the dryer to obtain a measured temperature, and calculates the circulating gas supplied to the dryer based on the measured temperature. Control the increase or decrease of the flow rate of the air supplied from the outside in such a manner that the temperature of the circulating gas approaches the target temperature. The sludge incineration system according to claim 2, wherein the dried sludge is not introduced into the dryer. A sludge incineration method is a sludge incineration method for incinerating sludge, which is characterized in that it has: a circulation step which circulates the circulation gas in the circulation path; a drying step of drying the first dewatered sludge in a dryer using the heat of the aforementioned circulating gas to generate dried sludge; a separation step, which separates the aforementioned dried sludge from the aforementioned circulating gas in a separator; A preheated air obtaining step of exchanging heat in an air preheater between air supplied from the outside and high-temperature incineration exhaust gas generated by incinerating the aforementioned sludge to generate preheated air; and, A step of obtaining high-temperature circulating gas, which exchanges heat between the aforementioned circulating gas and the aforementioned preheated air in the circulating gas heater to heat and generate high-temperature circulating gas; Wherein, the aforementioned circulating gas is discharged together with the aforementioned dried sludge from the aforementioned dryer, reaches the aforementioned circulating gas heater through the aforementioned separator, is heated, and is supplied to the aforementioned dryer again for circulation; In the drying step, the first dewatered sludge is pulverized while being dried to produce the dried sludge in the form of powder.

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