JP2011111480A - Carbonization system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbonization system which controls the temperature of a drying gas to be supplied to a drying machine by utilizing a heat exchanger. <P>SOLUTION: The carbonization system includes a drying machine 1 for drying a water-containing raw material with a drying gas, a carbonization furnace 2 for carbonizing the raw material dried by the drying machine 1, a secondary combustion furnace 3 for subjecting the exhaust gas discharged from the carbonization furnace 2 to combustion treatment, a cooling tower 4 for cooling the high-temperature combustion exhaust gas discharged from the secondary combustion furnace 3, and a heat exchanger 5 for heating a drying gas to circulate between the heat exchanger 5 and the drying machine 1 with the combustion exhaust gas after being cooled by the cooling tower 4 and has an exhaust section temperature detection means T1 to detect the temperature of the drying gas discharged from the drying machine 1 and a controller 30 for controlling the cooling tower 4, the controller 30 controlling the cooling tower 4 so as for the temperature detected by the exhaust section temperature detection means T1 to come to be nearly constant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a carbonization processing system that generates a carbide by heating a raw material that is an organic waste, and relates to a carbonization processing system that controls the temperature of a drying gas (hot air) for drying the raw material supplied to a carbonization furnace. .

  Organic wastes such as livestock manure discharged from barns are considered to be carbonized in order to effectively use them, and various carbonization processing systems have been proposed in recent years. FIG. 3 is a block diagram showing a carbonization processing system described in Patent Document 1 below. This carbonization treatment system 100 is provided with a carbonization furnace 101 for carbonizing sewage sludge (raw material) generated during sewage treatment at a sewage treatment plant to produce activated carbide, A gas turbine generator 102 in which a generator is connected to a gas turbine is combined. In the carbonization furnace 101, the raw material carried out from the dryer 103 is carbonized by heating in the carbonization furnace 101.

  The raw material sent to the carbonization furnace 101 is dehydrated by a centrifuge or the like to become a dehydrated cake, which is input as a raw material via the dryer 103. In the dryer 103, the dehydrated cake is dried with heated air (drying gas). This drying gas is heated by the heat of the carbonized exhaust gas in the heat exchanger 105, and the dryer 103 is supplied via the supply pipe 111. Sent to. The drying gas sent to the dryer 103 is returned to the heat exchanger 105 by the return pipe 112 and circulated. The supply pipe 111 is provided with a flow rate adjustment valve 121, and the flow rate is adjusted according to the temperature of the drying gas flowing through the return pipe 112. Further, a circulation pipe 114 branched from the exhaust pipe 113 is connected to the carbonization furnace 101, and the flow rate of the exhaust gas returned to the carbonization furnace 101 is adjusted by the flow rate control valve 122 according to the temperature of the exhaust gas flowing through the exhaust pipe 113.

JP 2005-125265 A

  In such a conventional carbonization processing system, a heat exchanger 105 is provided, and a drying heat source used in the dryer 103 is obtained from the carbonized exhaust gas by heat exchange. The temperature of the drying gas for recovering heat by the heat exchanger 105 is as follows. Not stable depending on usage conditions. On the other hand, although the moisture content of the raw material varies depending on the season and the like, it is desirable to supply the carbonized furnace 101 with a raw material having a stable dry state. Conventionally, the temperature of the drying gas is controlled by adjusting the heating power of the burner in the dryer 103. For this reason, the amount of fuel used for the burner is increased for a raw material with a large amount of water, which causes a problem in terms of cost.

  On the other hand, in order to reduce the fuel consumption of the burner, it is conceivable that the heating power of the burner is made constant and the raw material input amount to the dryer 103 is adjusted according to the temperature of the drying gas recovered from the heat exchanger 105. If the moisture content of the raw material is small, the drying gas heated by the heat exchanger 105 can be sufficiently dried. However, since the drying is fast, the amount of raw material discharged from the dryer 103 increases. In such a case, since the carbonization furnace 101 is operated at a constant processing speed, if the raw material discharged from the dryer 103 increases, the raw material will be excessively supplied. Therefore, in order to supply the raw material after drying in accordance with the processing speed of the carbonization furnace 101, there is a problem of increasing capital investment and complicated work such as providing a buffer tank for temporarily storing the raw material or removing the raw material from the line once. Occurs.

  Then, this invention aims at providing the carbonization processing system which adjusts the temperature of the gas for drying supplied to a dryer using a heat exchanger in order to solve this subject.

  The carbonization treatment system of the present invention includes a dryer for drying a moisture-containing raw material with a drying gas, a carbonization furnace for carbonizing the raw material dried by the dryer, and a combustion treatment of exhaust gas discharged from the carbonization furnace. Secondary combustion furnace, a cooling tower that cools high-temperature combustion exhaust gas discharged from the secondary combustion furnace, and a drying gas that circulates between the dryer and the combustion exhaust gas after cooling by the cooling tower A heat exchanger for heating, comprising: a discharge portion temperature detecting means for detecting the temperature of the drying gas discharged from the dryer; and a controller for controlling the cooling tower, the controller Is characterized in that the cooling tower is controlled so that the temperature detected by the discharge part temperature detecting means becomes substantially constant.

The carbonization processing system of the present invention has supply part temperature detection means for detecting the temperature of the drying gas supplied from the heat exchanger to the dryer, and the controller is detected by the discharge part temperature detection means. It is preferable that the cooling tower is controlled so that the temperature detected by the supply unit temperature detecting means is a predetermined temperature so that the temperature is substantially constant.
The carbonization processing system of the present invention has a pre-heat exchanger temperature detection means for detecting the temperature of the flue gas sent to the heat exchanger, and the controller detects the temperature detected by the discharge part temperature detection means is substantially the same. It is preferable that the cooling tower is controlled so that the temperature detected by the pre-heat exchanger temperature detecting means becomes a predetermined temperature so as to be constant.

The carbonization processing system of the present invention is configured so that the controller detects the cooling tower so that the temperature detected by the pre-heat exchanger temperature detection means does not exceed a set temperature determined for protecting the heat exchanger. It is preferable to control them.
The carbonization processing system of the present invention is such that when the controller confirms that the set temperature has been exceeded based on detection by the temperature pre-heat exchanger detection means, the warning means is operated. Is preferred.

  In the present invention, the controller controls the cooling tower so that the temperature of the drying gas discharged from the dryer has a substantially constant value. As a result, the temperature of the combustion exhaust gas sent to the heat exchanger is adjusted, and the temperature of the drying gas heated by the heat exchange with the combustion exhaust gas in the heat exchanger is set to the moisture content of the raw material charged into the dryer. Can be adjusted accordingly. Thus, since the temperature of the drying gas with respect to the moisture change of the raw material is not adjusted by the burner but by adjustment by heating in the heat exchanger, fuel consumption can be suppressed. In addition, a constant amount of raw material with a constant dry state can be stably supplied to the carbonization furnace by adjusting the temperature of the drying gas, preventing excessive drying, and eliminating cumbersome operations such as temporarily removing buffer tanks and raw materials Do not need.

It is a block diagram showing the carbonization processing system of an embodiment. It is a block diagram which shows the temperature management part of the gas for drying which comprises the carbonization processing system of FIG. It is a block diagram which shows the conventional carbonization processing system.

Next, an embodiment of the carbonization processing system according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a carbonization processing system.
A carbonization treatment system 10 according to the present invention includes a dryer 1 that dries a raw material containing moisture with a drying gas, and a carbonization furnace 2 that carbonizes the raw material dried by the dryer 1 as illustrated. Is provided. The carbonization furnace 2 is connected to a secondary combustion furnace 3 that combusts exhaust gas discharged from the carbonization furnace 2.

  Since the combustion-treated high-temperature combustion exhaust gas cannot be supplied to the heat exchanger 5 as it is, it is connected to the heat exchanger 5 through the cooling tower 4 provided on the downstream side of the secondary combustion furnace 3. Further, on the downstream side of the heat exchanger 5, an outside air preheater 6 that heats the outside air with the heat of the combustion exhaust gas and a final cooling tower 7 that cools the combustion exhaust gas that has passed through the outside air preheater 6 are sequentially provided.

In the carbonization processing system 10 of the present embodiment, livestock droppings or the like is used as a raw material for generating carbide, but the livestock droppings contain a lot of water. Therefore, drying is performed in the dryer 1 before being charged into the carbonization furnace 2. In the dryer 1, for example, about 65% of moisture contained in livestock droppings is dried to about 10%. The drying gas of the dryer 1 is heated by heat exchange with the combustion exhaust gas that passes through the heat exchanger 5, and therefore, the dryer 1 and the heat exchanger 5 are on the forward path through which the drying gas after the drying process flows. The piping 11 is connected by a return-side piping 12 through which the drying gas before the drying process flows, and the drying gas circulates between the two.
In addition, although the piping 17 for supplying a part of drying gas used with the dryer 1 to the carbonization furnace 2 is provided in the outward side piping 11, if this is unnecessary on a system, this will be It may be omitted. A pipe 18 for supplying a part of the drying gas heated by the heat exchanger 5 and dried (a quantity corresponding to the gas generated by drying the raw material) to the secondary combustion furnace 3 is provided in the return side pipe 12. Is provided.

  The raw material dried through the dryer 1 is sent to the carbonization furnace 2 by a conveyor. Examples of the carbonizing furnace 2 include a multi-stage screw carbonizing furnace proposed by the present applicant. In a multi-stage screw carbonization furnace, a plurality of screw conveyors are heated in the furnace body, and the raw material charged from the hopper is conveyed through the screw conveyor at a constant speed. And a carbide | carbonized_material is produced | generated when a raw material is heated and thermally decomposed within a screw conveyor.

Next, the carbonization furnace 2 is connected to a secondary combustion furnace 3 for burning the exhaust gas discharged. This is because it is necessary to remove dioxins contained in the exhaust gas and remove odors contained in the dry exhaust gas. Therefore, the secondary combustion furnace 3 is provided with a burner for burning the exhaust gas, and is configured to burn the exhaust gas at a temperature of 800 ° C. or higher.
The secondary combustion furnace 3 is connected to a cooling tower 4 that cools the combustion exhaust gas that has been subjected to the combustion treatment to a predetermined temperature. The predetermined temperature for cooling is preferably 750 ° C. or lower, preferably 700 ° C. or lower, considering the heat resistance of the heat exchanger 5 arranged on the downstream side and the prevention of flying ash adhesion.

  The cooling tower 4 is provided with a water spray cooling device that sprays cooling water onto a pipe through which combustion exhaust gas flows. The cooling tower 4 is connected with a reflux pipe 15 for adding the low-temperature combustion exhaust gas cooled through the outdoor air preheater 6 located further downstream to the high-temperature combustion exhaust gas. In the cooling tower 4, the flow rate of the low-temperature combustion exhaust gas sent through the recirculation pipe 15 is basically constant, and the temperature of the combustion exhaust gas is adjusted by controlling a water spray cooling device based on a temperature sensor described later. Yes.

  By the way, the supply of the low-temperature combustion exhaust gas through the recirculation pipe 15 has a cooling effect of the combustion exhaust gas and contributes to the reduction of the spray amount, and also increases the flow rate of the combustion exhaust gas fed to the heat exchanger 5. This is because a predetermined amount of drying gas is required to increase the drying effect in the dryer 1, and in order to efficiently perform heat exchange between the low-temperature drying gas and the high-temperature combustion exhaust gas, This is because it is effective to balance the flow rates of the two flowing through the heat exchanger 5. Therefore, the flow rate of the low-temperature combustion exhaust gas sent to the cooling tower 4 is set according to the flow rate of the drying gas flowing through the heat exchanger 5.

  The heat exchanger 5 exchanges heat between the high-temperature combustion exhaust gas and the dry air from the dryer 1, heats the drying gas that has fallen after the drying treatment to a predetermined temperature, and again dries the dryer 1. It is for sending in. An outside air preheater 6 is connected to the downstream side of the heat exchanger 5. The outside air preheater 6 performs heat exchange between the taken outside air and the combustion exhaust gas from the heat exchanger 5. A pipe 13 is connected to the outside air preheater 6 to the carbonization furnace 2 and the secondary combustion furnace 3 so that the outside air heated to about 120 ° C. can be supplied as combustion air to the carbonization furnace 2 and the secondary combustion furnace 3. It has become.

  In addition, a final cooling tower 7 is connected to the outside air preheater 6, and a pipe connecting the both branches to form a reflux pipe 15. The final cooling tower 7 is cooled to approximately 200 ° C. or less by cooling water sprayed with combustion exhaust gas. The gas burned, cooled, and collected through a bag filter (not shown) on the downstream side of the final cooling tower 7 is exhausted from the chimney.

  Next, FIG. 2 is a block diagram showing a temperature management unit for the drying gas constituting the carbonization processing system of FIG. The temperature management unit 20 is configured so that the drying gas circulated between the dryer 1 and the heat exchanger 5 has a substantially constant temperature at the outlet of the dryer 1. That is, the drying gas circulated between the heat exchanger 5 and the dryer 1 is dried into the raw material in the dryer 1 and sent to the heat exchanger 5 again in a state containing water vapor. The temperature of the drying gas discharged from the dryer 1 is made substantially constant.

  In the dryer 1, drying is performed so that the moisture of the raw material is about 10% and sent to the carbonization furnace 2. However, if the moisture content is large, the amount of heat of the drying gas is increased accordingly, When the amount of water is small, it is necessary to reduce the amount of heat of the drying gas. And the drying state of the raw material discharged | emitted from the dryer 1 can be stabilized by sending the drying gas which performed heat quantity adjustment appropriately to the dryer 1, and the drying discharged | emitted from the dryer 1 in that case This is because the temperature of the working gas becomes substantially stable as is the case with the raw material that is the object to be dried.

  The drying gas of the dryer 1 exchanges heat with the combustion exhaust gas by the heat exchanger 5, receives a predetermined amount of heat, and is sent to the dryer 1. In the temperature management unit 20, the temperature of the drying gas discharged from the dryer 1 (hereinafter referred to as “dryer discharge temperature”) (T1 ° C.) is supplied to the dryer 1 so as to be constant. The temperature of the drying gas (hereinafter referred to as “dryer supply temperature”) (T2 ° C.) is adjusted. Therefore, by controlling the temperature of the combustion exhaust gas flowing into the heat exchanger 5, the dryer supply temperature (T2 ° C.) of the drying gas subjected to heat exchange is set to an appropriate temperature.

  The temperature management unit 20 is provided with a controller 30 that controls the water spray cooling device 41 based on temperature detection by the temperature sensor T1 or the like. The controller 30 controls the entire carbonization processing system 10 shown in FIG. 1, but may be provided as a dedicated controller for the temperature management unit 20. The temperature management unit 20 includes a temperature sensor T1 that detects the dryer discharge temperature (T1 ° C.) and the dryer supply temperature (T2 ° C.) of the drying gas in the forward side piping 11 and the return side piping 12 of the dryer 1. T2 is provided. Furthermore, temperature sensors T3, T4, T5 for detecting the temperature of the flue gas after passing through the secondary combustion furnace 3 are provided. The temperature sensor T3 is the temperature sent to the cooling tower 4, and the temperature sensor T4 is heat exchange. The temperature supplied to the vessel 5, T 5, detects the temperature that has passed through the outside air preheater 6.

  The temperature of the combustion exhaust gas (hereinafter referred to as “heat radiation temperature”) (T4 ° C.) that exchanges heat with the drying gas in the heat exchanger 5 is adjusted by controlling the cooling tower 4 that cools the combustion exhaust gas upstream of the heat exchanger 5. Is done. A water spray cooling device 41 is installed in the cooling tower 4, and the temperature of the combustion exhaust gas is adjusted by the spray amount Q. As described above, the combustion exhaust gas is also cooled by the low-temperature combustion exhaust gas added through the reflux pipe 15, but since the flow rate of the low-temperature combustion exhaust gas is constant, the heat radiation temperature (T4 ° C) is controlled by water spray cooling. Will be performed by the device 41.

  In this embodiment, it is set to adjust the dryer supply temperature (T2 ° C.) of the drying gas so that the dryer discharge temperature (T1 ° C.) detected by the temperature sensor T1 is stabilized at 200 ° C., for example. . The dryer supply temperature (T2 ° C.) is a temperature at which when a predetermined amount of raw material containing about 65% of water is put into the dryer 1, it can be dried to about 10%. It is set to ℃. Therefore, if the dryer discharge temperature detected at T1 (T1 ° C.) is lower than 200 ° C., the dryer supply temperature (T2 ° C.) of the drying gas is raised and conversely exceeds 200 ° C. Is controlled to lower the dryer supply temperature (T2 ° C.).

  Further, such temperature control is performed by adjusting the heat release temperature (T4 ° C.) of the flue gas detected by the temperature sensor T 4 on the inlet side of the heat exchanger 5, and the heat release temperature (T 4 ° C.) is controlled by the cooling tower 4. It has come to be. That is, when the water spray cooling device 41 of the cooling tower 4 is controlled by the controller 30 and the dryer discharge temperature (T1 ° C.) detected at T1 is lower than 200 ° C., the spray amount Q of the water spray cooling device 41 is decreased. If the drying gas supply temperature (T2 ° C.) of the drying gas is increased and the temperature exceeds 200 ° C., the spray amount Q is increased to decrease the drying gas supply temperature (T 2 ° C.). ing.

  The temperature management unit 20 of the present embodiment controls the dryer supply temperature (T2 ° C.) to a predetermined temperature so that the dryer discharge temperature (T1 ° C.) is substantially constant. Control of the water spray cooling device 41 controls the water spray cooling device 41 based on direct information of the position where temperature control is performed, such as the dryer supply temperature (T2 ° C.) detected by the temperature sensor T2. In addition, it may be controlled based on the heat radiation temperature (T4 ° C.), which is indirect information detected by the temperature sensor T4, so that the dryer supply temperature (T2 ° C.) becomes a predetermined temperature. Furthermore, it is also possible to control the water spray cooling device 41 based on the temperature detected by the temperature sensors T3 and T5.

  By the way, the combustion exhaust gas must be sent to the heat exchanger 5 so that the heat radiation temperature (T4 ° C.) is 750 ° C. or lower (700 ° C. or lower if possible). The controller 30 controls the water spray cooling device 41 so that the heat radiation temperature (T4 ° C.) does not exceed 750 ° C. while keeping the dryer discharge temperature (T 1 ° C.) substantially constant. Note that the temperature detected by the temperature sensors T2 to T5 is about 825 ° C at the location of the temperature sensor T3 if the dryer supply temperature (T2 ° C) of the drying gas is set to 420 ° C. The heat radiation temperature (T4 ° C.) detected by the temperature sensor T4 is 725 ° C., and about 350 ° C. at the location of the temperature sensor T5.

  In the temperature management unit 20, when the heat radiation temperature (T4 ° C.) exceeds 750 ° C. or exceeds a predetermined threshold before 750 ° C., the controller 30 prevents the heat exchanger 5 from being damaged. However, an alarm lamp and an alarm buzzer (not shown) are operated, and the operation of the carbonization processing system 10 is stopped.

Subsequently, according to the carbonization processing system 10 having such a configuration, the following carbonization processing is performed.
At the start of operation, since the drying gas cannot be heated by the heat exchanger 5, the burner of the dryer 1 is used, or the raw material supplied with much moisture is carbonized in the carbonization furnace 2 over time. Thereafter, the combustion exhaust gas flows through the heat exchanger 5 and the operation is stabilized, whereby the drying gas circulated with the dryer 1 is heated by the heat exchanger 5. The drying gas is deprived of heat by the dryer 1 and is sent to the heat exchanger 5 at about 200 ° C. The heat exchanger 5 receives heat from the combustion exhaust gas and is heated to about 420 ° C. The gas is returned to the dryer 1 and the circulation is repeated.

  The raw materials such as livestock droppings put into the dryer 1 are subjected to a drying process with a drying gas heated by the heat exchanger 5. The raw material is fed into the carbonization furnace 2 in a dry state from which moisture is removed, for example, from about 65% to about 10%, although the amount of water varies depending on the season. In the carbonization furnace 2, the raw material is heated and pyrolyzed to become a carbide, and is recovered as a carbonized product through a cooling device (not shown).

  On the other hand, the exhaust gas generated in the carbonization furnace 2 is sent to the secondary combustion furnace 3 where it is burned at a high temperature of 800 ° C. or higher by a burner to detoxify harmful substances such as dioxins and remove odors. After such combustion treatment, the high-temperature combustion exhaust gas is sent to the cooling tower 4, where a certain amount of low-temperature combustion exhaust gas sent through the reflux pipe 15 is added to the combustion exhaust gas to lower the temperature and cooling. Cooling with water spraying is performed. By cooling in the cooling tower 4, the combustion exhaust gas is supplied to the heat exchanger 5, that is, a temperature at which the drying gas fed to the dryer 1 is heated to an appropriate temperature while setting the upper limit to 750 ° C., preferably 700 ° C. Adjusted.

  As described above, the dryer 1 is supplied with a drying gas heated to a dryer supply temperature (T2 ° C.) of about 420 ° C., for example, and dries the raw materials therein, and includes steam generated therein. The drying gas is discharged to the outward piping 11 and flows to the heat exchanger 5. At this time, the dryer discharge temperature (T1 ° C.) of the drying gas is detected by the temperature sensor T1, and the controller 30 performs temperature control based on the detection signal.

  When the moisture content of the raw material charged into the dryer 1 is large, the dryer discharge temperature (T1 ° C.) of the drying gas is lowered, so water spray cooling is performed to increase the dryer supply temperature (T 2 ° C.). The spray amount Q of the device 41 is decreased so that the heat release temperature (T4 ° C.) of the combustion exhaust gas is increased. Therefore, in the heat exchanger 5, the drying gas is heated by heat exchange with the combustion exhaust gas whose temperature has increased, and the drying gas having a heat amount corresponding to the increase in the moisture content is sent to the dryer 1. At this time, if the heat radiation temperature (T4 ° C.) exceeds 750 ° C. or exceeds a predetermined threshold, the controller 30 issues a warning by operating an alarm lamp or the like.

  On the other hand, when the moisture content of the raw material charged into the dryer 1 is small, the dryer discharge temperature (T1 ° C.) of the drying gas rises. The spray amount Q of the spray cooling device 41 is increased so that the heat release temperature (T4 ° C.) of the combustion exhaust gas is lowered. Therefore, in the heat exchanger 5, the drying gas is heated by heat exchange with the combustion exhaust gas whose temperature has dropped, and the drying gas having a heat amount corresponding to the increase in the moisture content is sent to the dryer 1.

  As described above, according to the carbonization processing system 10, the dryer supply temperature (T2 ° C) is adjusted so that the dryer discharge temperature (T1 ° C) of the drying gas becomes substantially constant. Even if the moisture content of the raw material charged into the dryer 1 is changed, the raw material in a stable dry state can be supplied to the carbonization furnace 2. Since the temperature adjustment of the drying gas is realized by controlling the water spray cooling device 41 of the cooling tower 4, the fuel power of the burner is not adjusted with respect to the moisture change of the raw material. It became possible to reduce consumption. In addition, a constant amount of raw material with a constant dry state can be stably supplied to the carbonization furnace 2 by adjusting the temperature of the drying gas, and it is necessary to add equipment using a buffer tank or to remove the raw material once. Could not do.

  And in such a carbonization processing system 10, when the moisture content of the raw material is small, the drying gas supply temperature (T2 ° C.) of the drying gas is suppressed, so that excessive drying of the raw material can be prevented. In that case, since the heat release temperature (T4 ° C.) of the flue gas sent to the heat exchanger 5 is lowered, the life of the heat exchanger 5 with a reduced high-temperature heat load can be extended. On the other hand, when the moisture content of the raw material is high, the heat release temperature (T4 ° C.) of the combustion exhaust gas becomes high, but the controller 30 warns based on the temperature detected by the temperature sensor T4, or heat exchange is performed by stopping the system operation. It is possible to prevent failure and malfunction of the device 5.

  Further, the low temperature combustion exhaust gas is sent to the cooling tower 4 from the reflux pipe 15, and the flow rate of the combustion exhaust gas flowing through the heat exchanger 5 is increased. Therefore, the flow rate balance with the drying gas that performs heat exchange is achieved, and the efficiency of heat exchange between the combustion exhaust gas on the heat radiation side and the drying gas on the heat receiving side is improved without increasing the size of the heat exchanger 5. And since the temperature of combustion exhaust gas is lowered | hung with the low temperature combustion exhaust gas in the cooling tower 4, the usage-amount of spray water can be reduced significantly. In the cooling of the spray water, the amount of heat consumed for the latent heat of vaporization is not used, and the amount of heat is lost. However, the amount of heat loss can be suppressed by pre-cooling the combustion exhaust gas with the low temperature exhaust gas.

  In addition, although embodiment about the carbonization processing system of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the summary.

DESCRIPTION OF SYMBOLS 1 Dryer 2 Carbonization furnace 3 Secondary combustion furnace 4 Cooling tower 5 Heat exchanger 6 Outside air preheater 7 Final cooling tower 10 Carbonization processing system 20 Temperature control part 11 Outward side piping 12 Return side piping 15 Recirculation piping 30 Controller 41 Water Spray cooling device T1, T2, T3, T4, T5 Temperature sensor

Claims (5)

A dryer for drying the raw material containing moisture with a drying gas, a carbonization furnace for carbonizing the raw material dried by the dryer, a secondary combustion furnace for combusting exhaust gas discharged from the carbonization furnace, A cooling tower that cools the high-temperature combustion exhaust gas discharged from the secondary combustion furnace, and a heat exchanger that heats the drying gas circulated between the dryer and the combustion exhaust gas after being cooled by the cooling tower. In the carbonization system
A discharge section temperature detecting means for detecting the temperature of the drying gas discharged from the dryer; and a controller for controlling the cooling tower, wherein the controller detects the temperature detected by the discharge section temperature detecting means. A carbonization system characterized in that the cooling tower is controlled to be substantially constant. In the carbonization processing system according to claim 1,
Supply unit temperature detection means for detecting the temperature of the drying gas supplied from the heat exchanger to the dryer, and the controller detects the temperature detected by the discharge unit temperature detection means to be substantially constant. In addition, the carbonization processing system is characterized in that the cooling tower is controlled so that the temperature detected by the supply part temperature detecting means becomes a predetermined temperature. In the carbonization processing system according to claim 1,
A pre-heat exchanger temperature detecting means for detecting the temperature of the flue gas sent to the heat exchanger, and the controller is configured to detect the heat so that the temperature detected by the discharge portion temperature detecting means is substantially constant. A carbonization system characterized in that the cooling tower is controlled so that the temperature detected by the pre-exchanger temperature detecting means is a predetermined temperature. In the carbonization processing system according to claim 3,
The controller controls the cooling tower so that a temperature detected by the temperature detection means before the heat exchanger does not exceed a set temperature determined for protecting the heat exchanger. A carbonization system characterized by being. In the carbonization processing system according to claim 4,
The controller is configured to operate a warning unit when it is confirmed that the set temperature has been exceeded based on detection by the temperature detection unit before the heat exchanger.

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