JP2005254055A - Method for drying and deodorizing organic sludge and system therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a safe and stable drying operation and realize energy saving in exhaust gas deodorizing treatment by using high-temperature air generated in a cement plant as a heat source. <P>SOLUTION: Dehydrated cakes are mixed in the surface of a large amount of dried sludge produced beforehand, and dry exhaust gas after drying the mixed sludge is induced by a drying fan 10. A part of the induced dry exhaust gas (a primary dry exhaust gas) is mixed with the high-temperature air through a first duct 11A to be used to dry the mixed sludge. The remainder of the dry exhaust gas (a secondary dry exhaust gas) is introduced into a combustion furnace 24 through a second duct 11B, thereby the dry exhaust gas is deodorized to generate exhaust gas. The secondary dry exhaust gas is passed through a heat exchanger 12 before being introduced into the combustion furnace 24, thereby heat is exchanged between the dry exhaust gas and the combustion exhaust gas from the combustion furnace 2 to reduce the temperature of the combustion exhaust gas. A part of the secondary dry exhaust gas heat-exchanged in the heat exchanger 12 is recovered, and mixed with the primary dry exhaust gas mixed with the high-temperature air. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and system for drying and deodorizing organic sludge.

  A conventional organic sludge drying and deodorizing treatment system 1 ′ is configured as shown in FIG. 2, for example. That is, the dewatered cake thrown in through the cake hopper 2 is supplied by the cake supply pump 3 to the dried sludge supply device 4 (the sludge cake inlet 4a). A dehydrated cake (dehydrated cake of organic sludge such as sewage sludge and industrial waste sludge) fed through the cake hopper 2 is transported by a vehicle or the like and is put into the cake hopper 2.

  In the dry sludge supply apparatus 4, the supplied dewatered cake is mixed with the surface of the granular dry sludge manufactured beforehand. The mixed sludge from the dry sludge supply device 4 is supplied to the crusher 6 through the chute 5 and pulverized together with a drying gas which is a hot air flow of 400 ° C. or less in which high-temperature gas and dry exhaust gas (primary dry exhaust gas) are mixed. Is done.

  The powder crushed in the crusher 6 is sent to a dust collector 8 through a drying duct 7 extending in a substantially vertical direction for airflow drying. The dust collector 8 is composed of first and second cyclones 8A and 8B.

  The upper part of the dust collector 8 (second cyclone 8B) is connected to a drying fan 10 through an exhaust gas duct 9. The duct on the downstream side of the drying fan 10 is branched into two. The first duct 11A is connected to the inlet of the crusher 6, and the second duct 11B is connected to the inlet of the heat exchanger 12. Thereby, the dry exhaust gas after drying mixed sludge is divided into the primary dry exhaust gas which flows through the 1st duct 11A, and the secondary dry exhaust gas which flows through the 2nd duct 11B. 11 A of 1st ducts have the adjustment valve 13 which adjusts the flow volume of the primary dry exhaust gas which flows through 11 A of 1st ducts in the downstream of the branch point with the 2nd duct 11B, and the branch point vicinity. The control valve 13 receives a signal from a current sensor 14 that detects a current value flowing through the drying fan 10 and adjusts the opening of the control valve 13 so that the current value detected by the current sensor 14 is constant. Is done. Thus, the flow rate of the primary dry exhaust gas flowing toward the crusher 6 is adjusted by the control valve 13.

  The second duct 11B is provided with a regulating valve 15 that regulates the flow rate of the secondary dry exhaust gas flowing through the second duct 11B. The control valve 15 receives a signal from the pressure sensor 16 that detects the pressure of the primary dry exhaust gas flowing through the first duct 11 </ b> A downstream of the control valve 13, the opening degree is adjusted, and the primary drying that flows toward the crusher 6. The flow rate of the secondary dry exhaust gas to the heat exchanger 12 is adjusted so that the pressure of the exhaust gas becomes constant.

  In addition, an introduction path 17 for introducing high-temperature gas (for example, combustion exhaust gas having a temperature of about 650 ° C. and a low oxygen concentration) is downstream of the detection position of the control valve 13 and the pressure sensor 16 in the second duct 11A. It is connected. The primary dry exhaust gas is mixed with the introduced high-temperature gas to obtain a drying gas. The introduction path 17 is provided with a control valve 18 that adjusts the flow rate of the hot gas in the introduction path 17, and the control valve 18 detects the temperature downstream of the drying fan 10 (upstream from the branch point). Receiving the signal from the temperature sensor 19 and adjusting the amount of the high-temperature gas (combustion exhaust gas) introduced through the introduction path 17 so that the temperature of the drying gas supplied toward the crusher 6 does not become too high. Has been.

  That is, the dehydrated cake is mixed with the surface of a large amount of dry sludge produced in advance, and the primary dry exhaust gas that is part of the dry exhaust gas after drying this mixed sludge is mixed with the high-temperature gas, and the gas temperature is adjusted. The temperature is lowered to 400 ° C. or lower and led to the crusher 6. This is because if a high-temperature gas of about 650 ° C. is used as it is as a heat source for drying, the organic sludge may ignite and burn.

  On the other hand, a dry sludge hopper 22 is connected to lower portions of the first and second cyclones 8A and 8B constituting the dust collector 8 via dischargers 21A and 21B, and a dry sludge discharge device is provided in the dry sludge hopper 22. 23 is arranged.

  A dry sludge supply device 4 that circulates a portion of the dry powder is provided below the dry sludge discharge device 23, and the dry sludge supply device 4 mixes the sludge cake and a portion of the dry powder that has been air-flow dried. Functions as a mixing unit.

  The heat exchanger 12 includes first and second heat exchanger units 12A and 12B. The secondary dry exhaust gas sent through the second duct 11B sequentially passes through the first and second heat exchanger sections 12A and 12B, and is heat-exchanged with the combustion exhaust gas from the combustion furnace 24.

  The gas exiting the second heat exchanger section 12B is sent to the combustion furnace 24, where it is deodorized by combustion. At this time, the LPG gas 25 is supplied to the combustion furnace 24 and the fuel is adjusted from the fuel tank 27 by the control valve 28 by the first and second fuel pumps 26A and 26B provided in parallel. , Sent with air. A combustion blower 29 supplies air for assisting combustion.

  As described above, the combustion exhaust gas from the combustion furnace 24 is sent to the heat exchanger 12 through the duct 30 for heat exchange. Then, the induction fan 31 is attracted through the duct 32 and discharged. The duct 32 is provided with a regulating valve 33 that regulates the flow rate of the combustion exhaust gas flowing through the duct 32.

  The combustion furnace 24 is provided with a pressure sensor 34 that detects internal pressure and a temperature sensor 35 that detects internal temperature. In accordance with the signal from the pressure sensor 34, the opening degree of the control valve 33 is adjusted, the amount of exhaust gas flowing through the induction fan 31 is controlled, and the internal pressure of the combustion furnace 24 becomes constant. Further, in response to a signal from the temperature sensor 35, the opening degree of the control valve 28 is adjusted, the amount of fuel supplied to the combustion furnace 24 is controlled, and the temperature inside the combustion furnace 24 is made constant. .

  By the way, most of the organic sludge such as sewage sludge and industrial waste sludge has been dehydrated and dried and then disposed of by incineration of organic matter in sludge in a fluidized bed furnace or rotary kiln. By putting it into a firing device and incinerating with a rotary kiln, the combustion heat of sludge is effectively utilized and the incinerated ash is recovered as part of the cement raw material.

  In addition, there is a need for a technique that efficiently uses high-temperature air generated in a cement factory (high-temperature air generated from a high-temperature clinker cooling process, temperature of about 800 ° C.) as a heat source for drying organic sludge.

By the way, by combining an air dryer with a cement firing device, providing an exhaust gas heating unit at the high temperature part of the cement firing device, and providing a heat exchanger part for preheating the exhaust gas dryer exhaust gas, the heat consumption of the cement firing device can be reduced. 2. Description of the Related Art A sludge treatment method and apparatus are known in which a large amount of sludge can be introduced without deteriorating as much as possible, and airflow dryer exhaust gas can be released without being brominated, and released into the atmosphere (see, for example, Patent Documents 1 and 2).
JP 2002-273480 A (paragraph 0009 and FIG. 1) JP 2002-273492 A (paragraph 0010 and FIG. 1)

  In the drying of organic sludge, when the above-described high-temperature air of about 800 ° C. is used as a heat source for drying, the temperature is higher than that of the conventional system. Therefore, in the conventional system, the primary dry exhaust gas circulated through the first duct 11A is mixed. Thus, the temperature of the drying gas supplied to the crusher 6 cannot be sufficiently lowered, the dried organic sludge is easily ignited, and the stable drying operation itself is difficult. On the other hand, as the heat source for drying, the higher the temperature, the higher the heat utilization efficiency.

  In addition, the dry exhaust gas of organic sludge has a strong odor, and as described above, the deodorization treatment is performed by burning the secondary dry exhaust gas in the combustion furnace, and this deodorization treatment requires a large amount of fuel. Since it is also necessary to supply combustion air corresponding to the fuel, the running cost is increased. In addition, since a large amount of combustion air is supplied in the combustion furnace, the combustion exhaust gas increases, the heat recovery rate in the heat exchanger decreases, and the combustion furnace becomes larger.

  The present invention can perform a safe and stable drying operation using, for example, high-temperature air of about 800 ° C. generated in a cement factory as a heat source for drying, and at the same time can save energy in the deodorization treatment of the dried exhaust gas. An object is to provide a method and system for drying and deodorizing organic sludge.

  In the invention of claim 1, a dehydrated cake is mixed with the surface of a large amount of dry sludge produced in advance, and a primary dry exhaust gas that is a part of the dry exhaust gas after drying this mixed sludge is mixed with a high-temperature gas. In addition, while being used for drying the mixed sludge, the secondary dry exhaust gas that is the remainder of the dry exhaust gas is introduced into a combustion furnace and burned to form a deodorized combustion exhaust gas. In the organic sludge drying and deodorizing treatment method, the secondary dry exhaust gas is heat-exchanged with the combustion exhaust gas from the combustion furnace and the temperature of the combustion exhaust gas is lowered before being introduced into the combustion furnace. The heat-exchanged secondary dry exhaust gas is partially recovered and mixed with the high-temperature gas or primary dry exhaust gas.

  In this way, the temperature of the drying gas used for drying the mixed sludge is appropriately adjusted by mixing a part of the heat-exchanged secondary dry exhaust gas with the primary dry exhaust gas mixed with high-temperature air. Can be efficiently reduced to a low temperature. In this case, the temperature of the heat-exchanged secondary dry exhaust gas is higher than that of the dried exhaust gas after drying the mixed sludge (primary dry exhaust gas). Therefore, the dried exhaust gas after drying the mixed sludge (primary drying) It is more efficient than increasing the amount of exhaust gas).

  Part of the heat-exchanged secondary dry exhaust gas can be recovered and the amount of dry exhaust gas combusted in the combustion furnace can be reduced, so the amount of fuel used for combustion can be reduced and the combustion furnace can be downsized. . In addition, since high-temperature air is used instead of high-temperature gas (combustion exhaust gas), oxygen contained in the dry exhaust gas can be used for combustion in the combustion furnace, so that combustion can be performed without using conventionally required combustion air. can do.

  As described in claim 2, it is desirable that the high-temperature gas or the primary dry exhaust gas is mixed with a part of the secondary dry exhaust gas before the heat exchange is completed.

  In this way, the secondary dry exhaust gas before heat exchange is completed is collected and mixed with the primary dry exhaust gas mixed with the high-temperature air, so the temperature of the dry exhaust gas (secondary dry exhaust gas) to be mixed This is advantageous in that it improves the heat recovery efficiency.

  A system for carrying out the inventions of the first and second aspects can be configured as described in the third to seventh aspects.

  In the invention of claim 3, a dehydrated cake is mixed on the surface of a large amount of dry sludge produced in advance, and the dried exhaust gas after drying this mixed sludge is attracted by a drying fan, and A part of the primary dry exhaust gas is mixed with high-temperature gas through the first duct and used for drying the mixed sludge, while the secondary dry exhaust gas as the remainder of the dry exhaust gas is introduced into the combustion furnace through the second duct. It is configured to deodorize by burning and become a combustion exhaust gas, and before introducing the secondary dry exhaust gas into the combustion furnace, the secondary dry exhaust gas is passed through a heat exchanger to pass from the combustion furnace. In the organic sludge drying and deodorizing treatment system that exchanges heat with combustion exhaust gas and lowers the temperature of the combustion exhaust gas, using high-temperature air as the high-temperature gas, between the first duct and the heat exchanger, Characterized in that a gas recovery mixing means to recover a part of the secondary drying gas which is heat-exchanged in serial heat exchanger are mixed to the hot gas or the primary drying gas.

  In this way, a part of the secondary dry exhaust gas heat-exchanged by the heat exchanger is mixed with the primary dry exhaust gas mixed with high-temperature air (high-temperature gas), thereby drying the mixed sludge. The temperature (for example, 400 degrees C or less) of service gas can be reduced efficiently. And like invention of Claim 1, since a part of secondary dry exhaust gas heat-exchanged is collect | recovered, the quantity of the dry exhaust gas combusted in a combustion furnace can be decreased, the usage-amount of the fuel for combustion can be suppressed, The combustion furnace can be downsized. Therefore, it can combust without requiring combustion air.

  Also, by effectively using the heat-exchanged secondary dry exhaust gas, the ratio of the dry exhaust gas to the amount of high-temperature air in the drying gas increases, and the water vapor concentration in the drying gas increases due to the water vapor generated in the drying operation. Since the oxygen concentration is reduced and supplied to the mixed sludge (of the crusher), it becomes difficult to ignite.

  The heat exchanger includes primary and secondary heat exchanger parts, and the gas recovery and mixing unit connects the primary heat exchanger part and the secondary heat exchanger part. A connecting duct, a first control valve that is provided in the connecting duct and adjusts a flow rate of gas flowing through the connecting duct, an upstream side of the first adjusting valve of the connecting duct, and the first duct, A communication duct that communicates with a portion upstream from the portion where the gas is introduced, and a part of the dry exhaust gas supplied from the primary heat exchanger section to the secondary heat exchanger section is recovered through the communication duct. Thus, it can be used for mixing with a part of the dry exhaust gas mixed with the high-temperature gas.

  In this way, by separating the primary heat exchanger part and the secondary heat exchanger part, the heat transfer area is increased, and when exchanging heat between the combustion exhaust gas and the secondary dry exhaust gas, efficient combustion is achieved. While reducing the temperature of the exhaust gas, the temperature of the secondary dry exhaust gas can be increased to facilitate combustion in the combustion furnace. Therefore, the heat recovery efficiency can be increased and the amount of fuel used can be suppressed.

  The primary dry exhaust gas that flows downstream from a connection portion between the temperature sensor that detects the temperature of the dry exhaust gas that flows downstream of the drying fan and the communication duct of the first duct, according to claim 5. A pressure sensor for detecting the pressure of the gas, and controlling the first control valve based on a signal from the temperature sensor and the pressure sensor to adjust the amount of recovered gas of the heat-exchanged secondary dry exhaust gas. It is desirable to have a control circuit for controlling the amount of hot gas introduced into the first duct.

  In this way, by controlling the first control valve, the flow rate of the primary dry exhaust gas flowing through the first duct is adjusted, and the introduction amount of high-temperature air in the first duct is controlled according to the gas amount. can do.

  According to a sixth aspect of the present invention, the second duct is provided with a second regulating valve that regulates the flow rate of gas flowing through the second duct, and the second regulating valve introduces the second regulating valve into the heat exchanger. The temperature of the dry exhaust gas on the downstream side of the drying fan can be controlled while adjusting the amount of the secondary dry exhaust gas.

  In this way, the temperature of the dry exhaust gas on the downstream side of the drying fan is controlled by adjusting the amount of the secondary dry exhaust gas introduced into the heat exchanger with the second control valve.

  As described in claim 7, it is desirable that the granular dried sludge produced in advance is 10 times or more the dehydrated cake.

  In this way, a large amount of dried sludge and dehydrated cake are mixed and supplied to the crusher, which is advantageous in preventing the ignition of the material by making the dried sludge surface wet.

  Since constituted as described above, the present invention can perform a safe and stable drying operation when drying organic sludge, for example, using high-temperature air generated in a cement factory as a heat source for drying, In addition, energy saving can be achieved in the deodorization treatment of the exhaust gas.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components as those in the conventional system shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 1 is a schematic explanatory view of an organic sludge drying and deodorizing treatment system according to the present invention.

  In FIG. 1, an organic sludge drying and deodorizing treatment system 1 according to the present invention uses a cake supply pump 3 to feed a dehydrated cake fed through a cake hopper 2 to a dried sludge supply device 4 (its sludge cake inlet 4a). ) Is the same as the conventional one.

  In the dried sludge supply device 4, the supplied dehydrated cake is mixed with the surface of a large amount of granular dried sludge prepared in advance. Thereby, the surface of dry sludge is maintained in a moist state. In addition, the granular dried sludge is 10 times or more the supplied dehydrated cake.

  The wet mixed sludge from the dry sludge supply device 4 is supplied to the crusher 6 and crushed together with the hot air flow (drying gas). Here, dry exhaust gas (primary dry exhaust gas) adjusted so that the current value of the drying fan 10 is constant, and dry exhaust gas (secondary dry exhaust gas) heat-exchanged by the heat exchanger 12 are mixed with high-temperature air. Thus, a hot air flow as a drying gas is formed. This hot air flow is a gas whose temperature is adjusted to 400 ° C. or lower.

  The second duct 11B also has a control valve 15 (second control valve) that adjusts the flow rate of gas flowing through the second duct 11B (flow rate of dry exhaust gas) near the branch point with the first duct 11A. Have. The adjusting valve 15 receives a signal from a temperature sensor 19 that detects the temperature of the dry exhaust gas downstream of the drying fan 10 and its opening degree is adjusted. As a result, the amount of the secondary dry exhaust gas flowing toward the heat exchanger 12 through the second duct 11B is adjusted, and as a result, the flow rate of the primary dry exhaust gas flowing through the first duct 11A is adjusted. In this way, the primary dry exhaust gas and the secondary dry exhaust gas are distributed between the first and second ducts 11A and 11B.

  In the first duct 11A, for example, high-temperature air generated in a cement factory (high-temperature air of about 800 ° C. generated from a cooling process of a high-temperature clinker) is introduced downstream of the detection position of the control valve 13 and the pressure sensor 16. Unlike the conventional system (see FIG. 2), the introduction path 17 is not provided with a regulating valve 18. Therefore, the amount of high-temperature air introduced through the introduction path 17 is determined according to the flow rate of the primary dry exhaust gas flowing toward the crusher 6.

  In the heat exchanger 12, a regulating valve 41 that adjusts the flow rate of gas flowing through the connection duct 42 (first valve) is connected to the connection duct 42 that supplies the secondary dry exhaust gas from the primary heat exchanger section 12 </ b> A to the secondary heat exchanger section 12 </ b> B. A control valve). At the same time, a part of the secondary dry exhaust gas flowing from the primary heat exchanger section 12A to the secondary heat exchanger section 12B is recovered, and the first duct 11A (on the downstream side of the control valve 13 and upstream of the pressure sensor 16). In order to return to the side), a communication duct 43 that connects the connection duct 42 of the heat exchanger 12 and the first duct 11A is provided. In this way, a portion of the secondary dry exhaust gas heat-exchanged by the heat exchanger 12 is recovered between the first duct 11A and the heat exchanger 12, and converted into the primary dry exhaust gas mixed with the high-temperature air. A gas recovery and mixing means for mixing is configured. Note that the temperature of the secondary dry exhaust gas returned to the first duct 11A is higher than that after drying the mixed sludge for heat exchange with the combustion exhaust gas.

  And the opening degree of the control valve 41 is controlled by the control circuit 44 based on the signals from the temperature sensor 19 and the pressure sensor 16, and the amount of gas introduced from the primary heat exchanger section 12A to the secondary heat exchanger section 12B. Is adjusted. As a result, the flow rate of the secondary dry exhaust gas collected through the communication duct 43 and mixed with the primary dry exhaust gas is adjusted, and as a result, the amount of high-temperature air introduced into the first duct 11A is controlled.

  That is, the control circuit 44 determines how much the measured pressure is deviated from the set value by the first determining unit that determines how much the measured temperature deviates from the set value by the signal from the temperature sensor 19 and the signal from the pressure sensor 16. Based on the determination result (signals from both determination units), a second determination unit that determines whether or not there is a deviation, and a control unit that controls to be close to the set value based on a signal with a larger deviation. As a result, the amount of recovered gas is adjusted by controlling the amount of secondary dry exhaust gas introduced from the primary heat exchanger section 12A to the secondary heat exchanger section 12B based on the signal having the larger deviation from the set value. Finally, the amount of high-temperature air introduced through the introduction path 17 is controlled. Further, based on the determination result, for example, it is possible to control based on a map in which the opening degree of the control valve 41 can be determined by the measured value by the temperature sensor 19 and the measured value by the pressure sensor 16.

  If it does in this way, with the heat exchanger 12, it heat-exchanges with respect to the primary dry waste gas (about 120 degreeC) mixed with high temperature air (for example, about 800 degreeC high temperature air generated in a cement factory) in the 1st duct 11A. By mixing a part of the secondary dry exhaust gas having a relatively high temperature, the temperature of the drying exhaust gas supplied to the crusher 6 becomes an appropriate drying temperature, that is, the dried organic sludge is difficult to ignite. It can be lowered without difficulty to a temperature of 400 ° C. or lower.

  In addition, in the drying gas, the proportion of dry exhaust gas (primary dry exhaust gas, secondary dry exhaust gas) with respect to the amount of high-temperature air is higher than before, so the water vapor concentration in the drying gas with water vapor generated in the drying operation Becomes higher. As a result, the oxygen concentration decreases. Therefore, since the drying gas having a high water vapor concentration and a low oxygen concentration is supplied to the crusher 6, the dried organic sludge is difficult to ignite. In addition, since a water vapor | steam density | concentration becomes high and the wet state is maintained on the surface of dry sludge, it becomes difficult to ignite.

  When heat recovery is performed by exchanging heat between the combustion furnace exhaust gas and the dried exhaust gas by the heat exchanger 12, the heat exchanger 12 is divided into a primary heat exchanger portion 12A and a secondary exchanger 12B, and the primary heat exchanger portion. Since a part of the secondary dry exhaust gas is collected before passing into the secondary heat exchanger section 12B after passing through 12A, the amount of the secondary dry exhaust gas passing through the secondary heat exchanger section 12B is reduced, The capacity of the heat exchanger section 12B can be reduced. Moreover, since the dry exhaust gas sent to the combustion furnace 24 decreases, the usage-amount of the fuel for burning it can be suppressed. Unlike conventional high-temperature gas (combustion exhaust gas having a temperature of about 650 ° C. and low oxygen concentration), since high-temperature air of about 800 ° C. is used, the oxygen concentration in the secondary dry exhaust gas (part of the drying gas) Since the oxygen can be used as combustion oxygen in a combustion furnace, it can be burned without the need for burner combustion air. Moreover, since the amount of combustion exhaust gas in the combustion furnace 24 can be reduced, an increase in exhaust gas temperature after heat recovery can be suppressed, the exhaust gas temperature after heat recovery can be efficiently reduced, and heat recovery efficiency can be increased.

It is a schematic explanatory drawing of the drying and deodorizing treatment system of organic sludge concerning the present invention. It is a schematic explanatory drawing of the drying and deodorizing treatment system of the conventional organic sludge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drying and deodorizing treatment system of organic sludge 4 Dry sludge supply apparatus 6 Crusher 10 Drying fan 11A 1st duct 11B 2nd duct 12 Heat exchanger 12A Primary heat exchanger part 12B Secondary heat exchanger part 15 Adjustment Valve (second control valve)
16 Pressure sensor 19 Temperature sensor 24 Combustion furnace 41 Control valve (first control valve)
42 Connection Duct 43 Communication Duct 44 Control Circuit

Claims (7)

The dehydrated cake is mixed with the surface of a large amount of dry sludge produced in advance, and the primary dry exhaust gas that is part of the dry exhaust gas after drying this mixed sludge is mixed with high-temperature gas to dry the mixed sludge. On the other hand, the secondary dry exhaust gas, which is the remainder of the dry exhaust gas, is introduced into the combustion furnace and burned to be deodorized to form a combustion exhaust gas, before the secondary dry exhaust gas is introduced into the combustion furnace. In the method for drying and deodorizing organic sludge, the secondary dry exhaust gas is heat-exchanged with the combustion exhaust gas from the combustion furnace, and the temperature of the combustion exhaust gas is lowered.
Using hot air as the hot gas,
A method for drying and deodorizing organic sludge, wherein a part of the heat-exchanged secondary dry exhaust gas is collected and mixed with the high-temperature gas or primary dry exhaust gas.   The method for drying and deodorizing organic sludge according to claim 1, wherein the high-temperature gas or the primary dry exhaust gas is mixed with a part of the secondary dry exhaust gas before heat exchange is completed. The dehydrated cake is mixed with the surface of a large amount of dry sludge produced in advance, and the dry exhaust gas after drying this mixed sludge is attracted by a drying fan, and the primary dry exhaust gas that is part of this attracted dry exhaust gas Is mixed with high-temperature gas through the first duct and used for drying the mixed sludge, while the secondary dry exhaust gas that is the remainder of the dry exhaust gas is introduced into the combustion furnace through the second duct and burned to deodorize it. It is configured as a combustion exhaust gas, and before introducing the secondary dry exhaust gas into the combustion furnace, heat exchange with the combustion exhaust gas from the combustion furnace by passing the secondary dry exhaust gas through a heat exchanger, In the organic sludge drying and deodorizing treatment system for lowering the temperature of the combustion exhaust gas,
Using hot air as the hot gas,
Gas recovery mixing means for recovering a part of the secondary dry exhaust gas heat-exchanged in the heat exchanger and mixing it with the high-temperature gas or primary dry exhaust gas between the first duct and the heat exchanger. An organic sludge drying and deodorizing system characterized by being provided. The heat exchanger has primary and secondary heat exchanger parts,
The gas recovery and mixing means includes a connection duct that connects the primary heat exchanger part and the secondary heat exchanger part, and a first control valve that is provided in the connection duct and adjusts a gas flow rate that flows through the connection duct; A communication duct that communicates the upstream side of the first control valve of the connection duct and the upstream part of the first duct from the site where the high-temperature gas is introduced,
The part of the secondary dry exhaust gas supplied from the primary heat exchanger unit to the secondary heat exchanger unit is recovered through the communication duct and used for mixing with the high-temperature gas or the primary dry exhaust gas. Organic sludge drying and deodorization treatment system. A temperature sensor for detecting the temperature of the dry exhaust gas flowing downstream of the drying fan;
A pressure sensor for detecting the pressure of the primary dry exhaust gas flowing downstream from the connection portion of the first duct with the communication duct;
The first control valve is controlled based on signals from the temperature sensor and the pressure sensor, and the amount of recovered gas of the heat-exchanged secondary dry exhaust gas is adjusted, whereby the high-temperature gas to the first duct is adjusted. The organic sludge drying and deodorizing treatment system according to claim 4, further comprising: a control circuit that controls the amount of the introduced water. The second duct is provided with a second control valve that adjusts the flow rate of gas flowing through the second duct,
The temperature of the dry exhaust gas on the downstream side of the drying fan is controlled by adjusting the amount of the secondary dry exhaust gas introduced into the heat exchanger by the second control valve. Organic sludge drying and deodorization treatment system.   The organic sludge drying and deodorizing treatment system according to any one of claims 3 to 6, wherein the large amount of granular dried sludge produced in advance is 10 times or more that of the dehydrated cake.

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