JP3908251B2 - Superheated steam circulation drying system - Google Patents

Description

  The present invention relates to a drying system that dries waste with high water content such as livestock excreta and sludge, and more particularly, a superheated steam circulation type that produces high-quality dry products by circulating superheated steam to sterilize and reduce waste. Relates to the drying system.

  Steam circulation drying and incineration system that reheats and recirculates water vapor evaporated from sludge, and heats and dries it in contact with sludge. "Technology" (Non-Patent Document 1).

In the sludge incineration technology described in the above document, the blower provided at the outlet of the dryer sucks the circulating steam that has fallen in temperature, sends it to the heater, heats it into high-temperature steam, and sends it back to the dryer. Sludge is a type of dryer that is filled with high-temperature steam, contacts with the steam to remove heat, evaporates its own moisture, and dries.
Therefore, the inside of a dryer will be in a weak negative pressure state as a result by an air blower.

  Furthermore, in the above technique, the amount of steam corresponding to the water evaporated from the sludge becomes surplus, enters the secondary combustion chamber of the furnace from the drying system, and the high-temperature combustion gas enters the secondary combustion chamber. It is mixed with steam and heated to deodorize.

  In addition, as prior art regarding the steam circulation type drying system, Japanese Patent No. 3502339 “Waste Treatment Device” (Patent Document 1) related to our rights, and Japanese Patent No. 2998412 “Gas Contact” related to the rights of other companies Type drying apparatus "(Patent Document 2).

Japanese Patent No. 3502339 Japanese Patent No. 2998412 Magazine "Indasuto" VOL9 NO6 1994 p20-p24, Akinori Terai "New sludge incineration technology"

  However, the above-mentioned conventional equipment is large-scale and is operated continuously for several months as used in a sewage treatment plant. However, the equipment is made smaller and the continuous operation period is about one week. Assuming that the existing equipment was downsized and used as it was, the following points were concerned.

  First, since the period of continuous operation is short, it is necessary to start up the equipment in a short time, and for this purpose, the multistage dryer and the circulation circuit are surely replaced with superheated steam at an early stage. Some mechanism is necessary.

  Second, even if the multistage dryer and the circulation circuit can be reliably replaced with superheated steam, a large-capacity refractory material is applied to the inside of the multistage dryer, especially in the multistage dryer, to store the heat inside the machine. A considerable amount of drain water is generated in the process of raising the temperature of the refractory material by condensation heat transfer of superheated steam, particularly until the temperature in the multistage dryer reaches 100 ° C. It was necessary to secure a recipient of the drain water.

Thirdly, rather than simply draining a considerable amount of drain water, efficient utilization is desired.
Further, in the above conventional technology, no special measures are taken against dirt in the dryer and the path, and the operation is stopped and the cleaning is periodically performed. Therefore, it has been desired to improve durability.

Fourthly, the above-mentioned conventional existing equipment incinerates dry sludge together with wood chips in a heat source furnace, and in the subsequent secondary combustion chamber, excess steam containing impurities such as odor corresponding to the water evaporated from the sludge. The system was designed to deodorize by mixing and heating, and the facility was supposed to be an incinerator.
As a result, existing facilities were subject to many administrative regulations.

  The present invention has been made in view of the above circumstances, and in order to shorten the preparation time for operation, a multistage dryer and a once-through boiler (auxiliary boiler) that reliably replaces the inside of the circulation circuit with superheated steam are provided. Equipped with a drainage recovery tank that accepts the generated drain water, and without draining the recovered drain water to the outside, it is effectively consumed by spraying and circulating in the steam circulation circuit. Filled with clean water and sprayed and circulated in the same way, efficiently cleaning the multi-stage dryer and the path to improve durability, and included in the surplus steam at the previous stage supplied to the hot gas generator An object of the present invention is to provide a superheated steam circulation drying system in which a deodorizing device that completely removes odors and dusts is provided, and the equipment can be classified as a combustion device rather than an incinerator.

The present invention relates to a superheated steam circulation type drying system for drying waste material by using superheated steam circulating , a multistage dryer for drying the raw material, a circulation circuit for circulating superheated steam in the multistage dryer, and a circulation circuit The steam circulation fan that circulates the steam inside, the heat from the steam circulation fan in the middle of the circulation circuit, and the heat exchanger for regenerating superheated steam to regenerate superheated steam, and the heat exchanger for regenerating superheated steam A hot gas generator that supplies gas, a deodorizer that deodorizes excess steam in the circulation circuit and supplies it into the hot gas generator, and an auxiliary boiler that feeds steam into the circulation circuit are generated from the auxiliary boiler. A first valve for supplying steam in the middle of the circulation circuit or stopping the supply is provided.

  In the superheated steam circulation type drying system, the present invention provides a drainage recovery tank for recovering drain water generated in the multistage dryer and / or the circulation circuit, and draining the drain water in the drainage recovery tank by opening the second valve. And a sprayer for spraying in a dryer.

  The present invention is characterized in that in the superheated steam circulation drying system, the drain water sprayed in the multistage dryer is heated by a heater by the exhaust heat of the hot gas generator.

  According to the present invention, in the superheated steam circulation type drying system, the third valve for flowing drain water generated in the multistage dryer or / and the circulation circuit into the waste water recovery tank, and the temperature in the multistage dryer reach a specific temperature. Is provided with a control unit that opens the third valve so as to collect drain water generated in the multi-stage dryer or / and the circulation circuit in the waste water collection tank.

  In the superheated steam circulation drying system, the present invention closes the third valve when the temperature in the multi-stage dryer reaches a specific temperature before charging the raw materials, and thereafter the outlet-side steam temperature of the multi-stage dryer is a set value. The drain water in the waste water recovery tank is controlled to be sprayed into the multi-stage dryer using the sprayer without passing through the heater only when exceeding the above.

  In the superheated steam circulation drying system, the present invention is provided with an adjustment valve that controls the amount of surplus steam introduced into the deodorizing device, and a flow rate control unit that predefines the flow rate of the superheated steam in the circulation circuit. The amount of surplus steam supplied to the hot gas generator via the deodorizing device is controlled by an adjustment valve linked with the control valve.

  In the superheated steam circulation drying system according to the present invention, after stopping the charging of raw materials, the first valve is opened, the steam from the auxiliary boiler is supplied to the circulation circuit, and the second valve is opened together. It is characterized in that the water in the waste water recovery tank can be sprayed into the multistage dryer using a sprayer after passing through a heater.

According to the present invention, a multi-stage dryer for drying raw materials, a circulation circuit for circulating superheated steam to the multi-stage dryer, a steam circulation fan for circulating steam in the circulation circuit, and a steam circulation fan in the middle of the circulation circuit A heat exchanger for regenerating superheated steam that heats steam from the steam, a hot gas generator for supplying hot gas to the heat exchanger for regenerating superheated steam, and heat by deodorizing surplus steam in the circulation circuit A deodorizing device for supplying gas into the gas generator and an auxiliary boiler for sending steam in the middle of the circulation circuit, and supplying the steam generated from the auxiliary boiler to the middle of the circulation circuit or stopping the supply since the over-heat steam circulating drying system provided with, by reliably replaced in a short time a multistage dryer and the circulation circuit in superheated steam, it is possible to in a short time operation preparation, further, deodorizer According Since the removal of odors fraction and dust such excess steam, facilities can be a classification of the combustion apparatus rather than an incinerator, the effect can be adjusted to supply the steam from the auxiliary boiler to the circulation circuit.

  According to the present invention, a drainage recovery tank that collects drain water generated in the multistage dryer or / and the circulation circuit, and a sprayer that sprays drain water in the drainage recovery tank in the multistage dryer by opening the second valve. Therefore, the drain water can be recovered and the drain water can be consumed on another occasion.

  According to the present invention, the drain water sprayed into the multi-stage dryer is the above-mentioned superheated steam circulation drying system that is heated by the heater by the exhaust heat of the hot gas generator, and thus can contribute to steam generation. There is an effect that preparation for driving can be shortened.

  According to the present invention, the third valve for flowing drain water generated in the multistage dryer or / and the circulation circuit into the wastewater recovery tank, and the multistage dryer or / or until the temperature in the multistage dryer reaches a specific temperature. And the above-mentioned superheated steam circulation drying system provided with a control unit that opens the third valve so as to collect the drain water generated in the circulation circuit in the waste water collection tank. Until the specific temperature is reached, there is an effect that the generated drain water can be recovered.

  According to the present invention, the control unit closes the third valve when the temperature in the multi-stage dryer reaches a specific temperature before charging the raw materials, and thereafter the outlet-side steam temperature of the multi-stage dryer exceeds the set value. Only in the case of the above-mentioned superheated steam circulation drying system that controls the spraying of drain water in the wastewater recovery tank into the multistage dryer using a sprayer without passing through a heater, the temperature becomes a specific temperature and the multistage drying is performed. When the steam temperature at the outlet side of the machine exceeds the set value, drain water that does not pass through the heater can be sprayed, and the inside of the multistage dryer and the inside of the circulation circuit can be adjusted to an appropriate temperature.

  According to the present invention, the adjustment valve for controlling the amount of surplus steam introduced into the deodorization device and the flow rate control unit for predefining the flow rate of the superheated steam in the circulation circuit are provided, and the deodorization is performed by the adjustment valve linked to the flow rate control unit. Since the superheated steam circulation drying system that controls the amount of surplus steam supplied to the hot gas generator via the device is used, there is an effect that surplus steam can be converted into hot gas by the flow rate in the circulation circuit.

  According to the present invention, after the material charging is stopped, the first valve is opened, the steam from the auxiliary boiler is supplied to the circulation circuit, and the second valve is opened at the same time. Since the superheated steam circulation type drying system is configured such that it can be sprayed into the multistage dryer using a sprayer after passing through the heater, there is an effect that the multistage dryer and the inside of the circulation circuit can be efficiently cleaned.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of Embodiment of the Present Invention]
The superheated steam circulation type drying system according to the embodiment of the present invention includes a multistage dryer and a once-through boiler (auxiliary boiler) that replaces the inside of the circulation circuit with superheated steam at an early stage, and waste water that receives a considerable amount of drain water. A recovery tank, and a sprayer and a steam circulation fan that sprays and circulates the recovered drain water to the steam circulation circuit, fills the water in the wastewater recovery tank when operation is stopped, and sprays and circulates in the same way A deodorizing device that completely removes odors and dusts contained in surplus steam in the previous stage supplied to the hot gas generator is provided.
This makes it possible to replace the multi-stage dryer and the circulation circuit with superheated steam at an early stage, recover a considerable amount of drain, spray and recirculate it to the steam circulation circuit, and stop operation. Sometimes the multi-stage dryer and the route are efficiently cleaned to improve durability and the equipment can be classified as a combustion device rather than an incinerator.

[Superheated steam drying]
In the superheated steam circulation drying system according to the embodiment of the present invention, an object to be dried is dried using superheated steam.
Superheated steam is steam obtained by adding heat to saturated steam (steam generated by evaporation or boiling at saturation pressure and temperature), and is steam having a temperature higher than 100 ° C. at atmospheric pressure.
Superheated steam has more heat than hot air or saturated steam, and has a better drying capacity. Further, superheated steam can be recirculated, has high thermal efficiency, and saves energy. This means that only the steam generated from the material to be dried is burned by the hot gas generator as surplus steam.
In addition, drying with superheated steam means drying in a low oxygen atmosphere, so there is almost no risk of fire.

[System Overview]
A superheated steam circulation drying system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a superheated steam circulation drying system according to an embodiment of the present invention.
As shown in FIG. 1, the superheated steam circulation drying system (this system) according to the embodiment of the present invention includes a multistage dryer 1, a wastewater recovery tank 2, a dust collector 3, and a steam circulation fan 4. The auxiliary boiler 5, the deodorizing device 6, the fueling device 7, the hot gas generator 8, the heat exchanger 9 for regenerating superheated steam, the cooling tower 10, the exhaust gas purifying device 11, the exhaust fan 12, The exhaust tube 13, the fifth valve 14, the first valve 18, the second valve 20, and the fourth valve 21 are basically provided.
In addition to the valves shown in FIG. 1, this system includes many valves, and further necessary valves will be described with reference to FIG.

[Each part]
Hereinafter, each part of this system is demonstrated concretely.
[Multi-stage dryer]
The multi-stage dryer 1 is provided with a supply unit for drying objects such as sludge at the top, a plurality of drying floor surfaces are provided in the internal chamber, and a plurality of rakes for transferring the drying objects to the drying floor surfaces. Is provided.
That is, the material to be dried carried in from the supply unit is rotated along the rake, sent out, transferred, dropped downward from the carry-out end on the other end side of the dry floor surface, and dried from the lowermost discharge port. The processed raw material is discharged.

  Furthermore, a large-capacity refractory material is pasted inside the multi-stage dryer 1 in order to store heat inside the machine. The refractory material generates a considerable amount of drain water in the process of raising the temperature due to the condensation heat transfer of superheated steam, particularly until the temperature in the multistage dryer reaches 100 ° C.

The multi-stage dryer 1 includes a plurality of sprayers 1a inside.
The sprayer 1a sprays the water in the drainage frequency tank 2 into the multistage dryer 1 by specific control. Specific control will be described later.

In addition, the multistage dryer 1 is formed with an introduction part for introducing superheated steam into the room and a lead-out part for deriving superheated steam from the room.
The superheated steam introduced from the introduction part flows from the carry-in side of the dry floor surface to the carry-out side and flows out from the lead-out part. A path is formed.

[Drainage collection tank]
The drainage recovery tank 2 is a tank for recovering a considerable amount of drain water generated before the temperature in the multistage dryer 1 and the path rises to 100 ° C., and the temperature in the multistage dryer 1 and the path is 100 ° C. The drain water in the tank is sprayed and consumed in the multi-stage dryer 1 by the sprayer 1a in the process of exceeding the high temperature superheated steam atmosphere.
In FIG. 1, the drain water in the waste water recovery tank 2 is heated by a heater provided between the superheated steam regeneration exchanger 9 and the cooling tower 10 and then sprayed by the sprayer 1 a in the multistage dryer 1. Thus, steam generation can be promoted in the multistage dryer 1.
In addition, in a heater, the pipe which flows drain water is provided and the drain water is indirectly heated by heating the said pipe with exhaust heat.

Further, the drainage recovery tank 2 is controlled so as to always maintain a certain amount of water level, and purified water is stored during continuous operation.
Furthermore, after the purified water in the waste water recovery tank 2 is heated with a heater during idle operation after the supply of the raw material is stopped, the multistage dryer 1 and the cleaning in the path are sprayed into the multistage dryer 1 with the sprayer 1a. Is to do.
The drain water spray control will be described later.

[Dust collector]
The dust collector 3 is a device that collects dust scattered in the closed circuit in a sealed state.
Specifically, the dust collector 3 includes an introduction unit that introduces circulating steam derived from the deriving unit of the multistage dryer 1, and includes a deriving unit that derives the steam circulation fan 4.

[Steam circulation fan]
The steam circulation fan 4 is a fan that circulates steam in a certain direction in the pipe.
Specifically, the steam circulation fan 4 transfers the steam led out from the dust collector 3 to the superheated steam regeneration heat exchanger 9.
A part of the steam transferred to the heat exchanger 9 for regenerating superheated steam is introduced into the deodorizing device 6 through the fifth valve 14 as surplus steam.
Therefore, the operation of the steam circulation fan 4 results in a negative pressure inside the multistage dryer 1.

[Auxiliary boiler]
The auxiliary boiler (through-flow boiler) 5 supplies new steam to the superheated steam circulation path through piping to a part of the low-temperature side steam sent from the multistage dryer 1 to the heat exchanger 9 for regenerating superheated steam.
In particular, the auxiliary boiler 5 contributes to the realization of a superheated steam atmosphere at an early stage by replacing the air in the multistage dryer 1 with steam at the start of operation.
The exhaust from the auxiliary boiler 5 is exhausted through the exhaust cylinder 13.

[Deodorization equipment]
A part of the low-temperature side steam sent from the multi-stage dryer 1 to the heat exchanger 9 for regenerating superheated steam is discharged as surplus steam to the hot gas generator 8, but the deodorizer 6 is placed upstream of the hot gas generator 8. Is provided.

The deodorization apparatus 6 decomposes and removes impurities contained in excess steam and odor components such as hydrogen sulfide (H ₂ S) and ammonia (NH ₃ ) using, for example, an oxidation catalyst.
A specific configuration of the deodorizing device 6 will be described later.

[Fueling device]
The fueling device 7 stabilizes the dried product discharged from the multi-stage dryer 1 and mixes it with wood chips to make it the main fuel, and then supplies it to the hot gas generator 8.

[Hot gas generator]
The hot gas generator 8 generates the hot gas by completely burning the main fuel supplied from the fuelizer 7.
It should be noted that heavy oil or the like is used as auxiliary fuel only during start-up and stop.
Furthermore, the hot gas generator 8 introduces and burns surplus steam deodorized from the deodorizer 6 and converts it into hot gas.

[Heat exchanger for regenerating superheated steam]
The heat exchanger 9 for regenerating superheated steam heats the circulating steam using the hot gas generated by the hot gas generator 8 as a heat source.

[cooling tower]
The cooling tower 10 is a cooling device for cooling the exhaust gas discharged from the superheated steam regeneration exchanger 9.
[Exhaust gas purification equipment]
The exhaust gas purification device 11 is a device for purifying exhaust gas.
[Exhaust fan]
The exhaust fan 12 ensures an appropriate negative pressure in the hot gas generator 8, and sucks the exhaust from the exhaust gas purification device 11 and discharges it to the exhaust cylinder 13.
[Exhaust pipe]
The exhaust cylinder 13 is a cylinder that exhausts exhaust from the exhaust fan 12 and the auxiliary boiler 5.

[Fifth valve (CV-05)]
The fifth valve (CV-05) 14 adjusts the amount of steam that flows from the steam circulation fan 4 to the pipe of the heat exchanger 9 for regenerating superheated steam as a surplus steam and flows into the deodorizer 6. It is a regulating valve.
Control of the fifth valve (CV-05) 14 will be described later.

[Specific configuration of deodorization device]
Next, a specific configuration of the deodorizing apparatus 6 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram of the deodorizing apparatus.
As shown in FIG. 2, the deodorizing device 6 is provided with an air inlet 61 at the upper portion of the device main body 60, an exhaust port connected to the fan 66 at the lower portion of the main body 60, and a multistage inside the main body 60. A filter medium (for example, a sintered porous filter medium) is disposed, and a nozzle 62 for spraying a deodorizing liquid on the filter medium is installed.

A pump 65 is connected to the nozzle 62 to supply the deodorizing liquid in the tank 64 to the nozzle 62.
The fan 66 provided at the discharge port of the main body 60 discharges the air in the main body 60 from the exhaust port 67.

[Operation of deodorizing device]
The odorous air flows into the inlet 61 of the deodorizing device 6 through the fifth valve (CV-05) 14, and the filter medium is sprayed with deodorized liquid from the nozzle. It passes and is deodorized.
The deodorized air is exhausted from the exhaust port by the fan 66.
The concentration of the deodorizing liquid and the spraying time are adjusted according to the odor concentration.

  The basic mechanism of deodorization in the deodorization apparatus is oxidative decomposition, which instantly decomposes and deodorizes malodorous substances by oxidation-reduction reaction or strong ion exchange action.

[Control mechanism]
Next, the control mechanism in this system will be described with reference to FIG. FIG. 3 is a configuration block diagram of the control mechanism.
As shown in FIG. 3, the control mechanism is not illustrated, but includes a control unit that performs overall control, a first valve (V-01) 18, a second valve (CV-02) 20, and the like. A fourth valve (CV-04) 21, a fifth valve (CV-05) 14, a sixth valve (V-06) 15, and a first temperature measuring unit (TE-1) 23, , Second temperature measuring unit (TE-2) 24, third temperature measuring unit (TE-3) 19, fourth temperature measuring unit (TE-4) 17, and pressure measuring unit (PX-1 ) 16, a flow rate measuring unit (FX-1) 25, a drainage pump 22, a steam circulation fan 4, an exhaust fan 12, and the like.

[Control unit]
The control unit operates / controls each unit according to the measurement value at each measurement unit, and operates / stops the drain pump 22, operates the steam circulation fan 4 and the exhaust fan 12, and controls the number of rotations thereof. For example, the pressure measured by the first to fourth temperature measuring units is input, and the pressure measured by the pressure measuring unit (PX-1) 16 and the flow rate measuring unit (FX-1) 25 is input. Or the value of flow volume is input and the opening and closing of the 1st-6th valve is controlled according to those values.
The control unit can set (store) a plurality of times, and includes a timer for measuring the times.

Specifically, the control unit is realized by computer processing, and loads a processing program stored in the storage unit into the main memory and executes control processing.
In addition, about the part which controls the flow volume of the superheated steam in a circulation circuit, the flow volume control part is provided separately from the control part, and the flow volume control part is the 5th valve (CV-05) 14 according to the flow rate prescribed | regulated previously. The surplus steam amount supplied to the hot gas generator 8 via the deodorizing device 6 may be controlled.
Details of the processing before the raw material charging and the processing after the raw material charging stop in the control unit will be described later.

[First valve (V-01)]
The first valve (V-01) 18 is controlled to spray the water supplied from the drainage recovery tank 2 by the drainage pump 22 into the multistage dryer 1 via the hot gas exhaust path (heater). It has become a valve.
In particular, when water passes through the hot gas exhaust path, the water sprayed into the multistage dryer 1 is heated and the temperature is high. Therefore, it can contribute to steam generation, and the operation preparation period can be shortened.

[Second valve (CV-02)]
The second valve (CV-02) 20 is a valve for spraying the water transferred from the drainage recovery tank 2 by the drainage pump 22 directly into the multistage dryer 1.
By opening the second valve (CV-02) 20, when the temperature in the multistage dryer 1 becomes too high, it can be cooled.

[Fourth valve (CV-04)]
The fourth valve (CV-04) 21 is a valve provided in the middle of the pipe connecting the discharge port provided on the bottom surface of the multistage dryer 1 and the inlet of the waste water recovery tank 2.
The fourth valve (CV-04) 21 is opened when drain water is generated in the multi-stage dryer 1 and collects the drain water in the drainage recovery tank 2, and superheated steam is circulated. The case is closed.

[Fifth valve (CV-05)]
The fifth valve (CV-05) 14 is a valve for supplying surplus steam in the circulation path to the hot gas generator 8 through the deodorizing device 6.
The degree of opening and closing of the fifth valve (CV-05) 14 is adjusted according to the value of the flow rate measured by the flow rate measurement unit (FX-1) 25.

[Sixth valve (V-06)]
The sixth valve (V-06) 15 is a valve for supplying the steam from the auxiliary boiler 5 to the circulation path.
The sixth valve (V-06) 15 is opened when the auxiliary boiler 5 is started, and is closed when the auxiliary boiler 5 is stopped.

[First temperature measurement unit (TE-1)]
The first temperature measuring unit (TE-1) 23 is a measuring device for measuring the temperature in the multistage dryer 1.
The first temperature measurement unit (TE-1) 23 is desirably set at a place where the average temperature in the multi-stage dryer 1 is measured in relation to the second and third temperature measurement units.

[Second temperature measurement unit (TE-2)]
The second temperature measuring unit (TE-2) 24 is a temperature measuring device provided on the inlet side of the multistage dryer 1 in the circulation path, and is used for measuring the temperature of the superheated steam on the high temperature side.

[Third temperature measurement unit (TE-3)]
The third temperature measuring unit (TE-3) 19 is a temperature measuring device provided on the outlet side of the multistage dryer 1 in the circulation path, and is used for measuring the temperature of the superheated steam on the low temperature side.

[Fourth temperature measurement unit (TE-4)]
The fourth temperature measuring unit (TE-4) 17 is a temperature measuring device that measures the temperature on the outlet side of the hot gas generator 8. Since the temperature on the outlet side of the hot gas generator 8 is a high temperature of 700 to 800 ° C., the fourth temperature measuring unit (TE-4) 17 needs to be a temperature measuring device capable of measuring a high temperature.

[Pressure measurement unit (PX-1)]
The pressure measuring unit (PX-1) 16 is for measuring the pressure in the multi-stage dryer 1, and is particularly for measuring whether or not the inside of the multi-stage dryer 1 is a negative pressure.
[Flow measurement unit (FX-1)]
The flow rate measuring unit (FX-1) 25 measures the flow rate in the circulation path.

[Drainage pump]
The drainage pump 22 pushes up the water in the drainage recovery tank 2 and supplies it to the sprayer 1a in the multistage dryer 1 via the first valve (V-01) 18 or the second valve (CV-02) 20. To do.
Further, the drainage recovery tank 2 is provided with a mechanism for keeping the amount of water constant, and when the amount of water falls below a certain amount, purified water is replenished.

[Process until raw material input]
Next, a process until the raw material is charged into the multistage dryer 1 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the first half of the process until the raw material is charged in the control unit, and FIG. 5 is a flowchart showing the latter half of the process until the raw material is charged in the control unit. Note that (A) in FIG. 4 is connected to (A) in FIG.

  As shown in FIG. 4, when the system is started, the control unit first opens the fourth valve (CV-04) 21 that supplies drain water generated in the multistage dryer 1 to the drainage recovery tank 2. (S1). Then, the auxiliary boiler 5 is activated (S2), and the sixth valve (V-06) 15 is opened (S3). Subsequently, the steam circulation fan 4 is activated (S4).

Thereafter, two processes are performed. In one process, the control unit inputs the pressure value measured by the first pressure measuring unit (PX-1) 16 in the multistage dryer 1 (S5). Next, it is determined whether or not the inside of the multi-stage dryer 1 has a negative pressure based on the input value (S6).
If the inside of the multistage dryer 1 is negative pressure (in the case of Yes), the determination process S6 is repeated. If the inside of the multistage dryer 1 is not negative pressure (in the case of No), the rotation speed of the steam circulation fan 4 is increased (S7), the inside of the multistage dryer 1 is made negative pressure, and the process returns to the determination process S6.

In the other process following the process S4, the exhaust fan 12 is activated (S8), and then the hot gas generator 8 is activated (S9). The control unit is the fourth temperature measurement unit (TE-4). The value of the temperature at the outlet of the hot gas generator 8 measured in 17 is input (S10).
It is determined whether or not the input value of the outlet temperature of the hot gas generator 8 is 780 ° C. or higher (hot gas outlet temperature of the hot gas generator ≧ 780 ° C.) (S11).

  If the outlet temperature of the hot gas generator is less than 780 ° C. (in the case of No), the determination process S11 is repeated. If the outlet temperature of the hot gas generator is 780 ° C. or higher (in the case of Yes), the drain pump 22 is activated (S12), and the water in the drain collection tank 2 is transferred. Then, the first valve (V-01) 1 is opened (S13), and water heated by exhaust heat can be supplied into the multistage dryer 1.

  Next, as shown in FIG. 5, the control unit inputs the temperature value measured by the first temperature measurement unit (TE-1) 23 that measures the temperature in the multistage dryer 1 (S14), It is determined whether the temperature in the multi-stage dryer 1 has reached 100 ° C. or more (multi-stage dryer internal temperature ≧ 100 ° C.) (S15), and if the temperature in the multi-stage dryer 1 is less than 100 ° C. (No The determination process S15 is repeated.

  If the internal temperature of the multi-stage dryer 1 reaches 100 ° C. or higher in the determination process S15 (in the case of Yes), the timer is operated for a specific time (S16), and after the specific time has elapsed, the fourth valve (CV− 04) Close 21 (S17). The specific time is about 30 minutes.

  Subsequently, the control unit inputs the temperature measured by the third temperature measuring device (TE-3) 19 that measures the temperature in the circulation path on the outlet side of the multistage dryer 1, and the outlet temperature of the circulating superheated steam is It is determined whether it is 150 ° C. or higher (the outlet temperature of the circulating superheated steam ≧ 150 ° C.) (S19). If the outlet temperature of the circulating superheated steam is lower than 150 ° C. (in the case of No), the determination process S19 is repeated. .

  When the outlet temperature of the circulating superheated steam reaches 150 ° C. or higher (in the case of Yes), the following two processes are performed. In one of the processes, the opening and closing of the second valve (CV-02) 20 is adjusted so that the third temperature measuring unit (TE-3) 19 has a constant temperature of 150 ° C. (S20). When the second valve (CV-02) 20 is opened, the water in the drainage recovery tank 2 is sprayed by the sprayer 1a, so that the multistage dryer 1 and the outlet side of the circulation circuit can be cooled.

  In the other process, the controller inputs the temperature measured by the second temperature measuring device (TE-2) 24 that measures the temperature in the circulation path on the inlet side of the multi-stage dryer 1, and the circulating superheated steam It is determined whether or not the inlet temperature of the circulating superheated steam is 400 ° C. or more (inlet temperature of the circulating superheated steam ≧ 400 ° C.) (S21), and if the inlet temperature of the circulating superheated steam is less than 400 ° C. (in the case of No), it is determined. The process S21 is repeated.

When the inlet temperature of the circulating superheated steam reaches 400 ° C. or more (in the case of Yes), the first valve (V-01) 18 is closed (S23), the auxiliary boiler 5 is stopped (S24), and the sixth valve ( V-06) 15 is closed (S25).
By performing the above processing, it is possible to start the raw material charging.

Next, the processing after stopping the material charging will be described with reference to FIG. FIG. 6 is a flowchart showing a process after the material charging is stopped.
As shown in FIG. 6, when the raw material charging is stopped, the control unit operates the timer for a specific time (S31), and activates the auxiliary boiler 5 after the specific time has elapsed (S32). The specific time is about 2 to 3 hours.

  Next, the sixth valve (V-06) 15 is opened (S33), the timer is operated for a specified time (S34), and the multistage dryer 1 is stopped after the specified time has elapsed (S35). Then, the drainage pump 22 is activated and the first valve (V-01) 18 is opened (S37).

  Then, the timer is operated for a specified time (S38), and after the specified time has elapsed, the first valve (V-01) 18 is closed (S39), the drainage pump is stopped (S40), and the auxiliary boiler 5 is stopped (S41). ), The sixth valve (V-06) 15 is closed (S42). The specific time is a time for cleaning by spraying clean water stored in the waste water recovery tank 2 into the multistage dryer 1.

Next, the hot gas generator 8 is stopped (S43), the timer is operated for a specified time (S44), the exhaust fan 12 is stopped after the specified time has elapsed (S45), and then the steam circulation fan 4 is stopped. (S46). The specific time is a time for exhausting the hot gas remaining in the exhaust pipe after the hot gas generator 8 is stopped.
As described above, the processing after stopping the material charging is performed.

[Effect of the embodiment]
According to this system, by providing the deodorizing device 6 using an oxidation catalyst before the surplus steam is sent to the hot gas generator 8, impurities and odor components contained in the surplus steam are decomposed and removed, There is an effect that pure steam can be combusted in the gas generator 8. Accordingly, the hot gas generator 8 is fed with surplus superheated steam containing only H ₂ O, and this steam reacts in the same way as air when mixed with the hot gas generated by the combustion of the solid fuel. Since it only brings about the result of an increase in the amount of gas when combined with the descent, it is not incinerated and does not correspond to an incinerator.

  According to this system, the auxiliary boiler 5 is provided so that the steam generated by the auxiliary boiler 5 is supplied to the superheated steam circulation path, so that the air in the superheated steam circulation path is replaced with steam and circulated. Then, the hot gas generator 8 is operated and the steam is heated by the heat exchanger 9 for regenerating the superheated steam, so that the inside of the superheated steam circulation path becomes a predetermined superheated steam atmosphere in a short time, and the preparation for operation is made in a short time. There is an effect that can be terminated.

  According to this system, by providing the sprayer 1a in the waste water recovery tank 2 and the multi-stage dryer 1, the drain water generated in the multi-stage dryer 1 is recovered, and the temperature is higher than 100 ° C in the path. In the process of reaching the superheated steam atmosphere, drain water can be supplied and consumed in the multistage dryer 1 by the sprayer 1a, and when the temperature on the outlet side of the multistage dryer 1 in the circulation path becomes too high, The drain water can be supplied and cooled to keep the temperature constant. Further, the purified water is sprayed and supplied into the multistage dryer 1 during the idle operation after the raw material supply is stopped. As a result, the multi-stage dryer 1 and the inside of the path can be cleaned, and the life of the equipment can be extended.

  In the present invention, the inside of the multi-stage dryer and the circulation circuit can be surely replaced with superheated steam at an early stage, and a considerable amount of drain can be recovered and sprayed and recirculated to the steam circulation circuit for reuse. It is suitable for a superheated steam circulation drying system in which the multi-stage dryer and the route in the passage are efficiently cleaned during the period to improve durability and the equipment can be classified as a combustion apparatus instead of an incinerator.

It is a schematic block diagram of the superheated steam circulation type drying system which concerns on embodiment of this invention. It is a schematic block diagram of a deodorizing apparatus. It is a block diagram of the configuration of the control mechanism. It is a flowchart which shows the process of the first half until the raw material injection | throwing-in in a control part. It is a flowchart which shows the process of the latter half until the raw material injection | throwing-in in a control part. It is a flowchart which shows the process after a raw material addition stop.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Multi-stage dryer, 2 ... Waste water collection tank, 3 ... Dust collector, 4 ... Steam circulation fan, 5 ... Auxiliary boiler, 6 ... Deodorizing device, 7 ... Fuel conversion device, 8 ... Hot gas generator, 9 ... Overheating Steam regeneration heat exchanger, 10 ... Cooling tower, 11 ... Exhaust gas purification device, 12 ... Exhaust fan, 13 ... Exhaust tube, 14 ... Fifth valve (CV-05), 15 ... Sixth valve (V-06 ), 16 ... Pressure measuring part (PX-1), 17 ... Fourth temperature measuring part (TE-4), 18 ... First valve (V-01), 19 ... Third temperature measuring part (TE- 3), 20 ... second valve (CV-02), 21 ... fourth valve (CV-04), 22 ... drainage pump, 23 ... first temperature measuring unit (TE-1), 24 ... second Temperature measurement unit (TE-2), 25 ... flow rate measurement unit (FX-1), 60 ... main body, 61 ... intake port, 62 ... nozzle, 63 ... filter medium, 64 ... tank, 6 ... pump, 66 ... fan, 67 ... exhaust port

Claims (7)

A superheated steam circulation drying system for drying waste materials by circulating superheated steam,
A multi-stage dryer for drying the raw materials;
A circulation circuit for circulating superheated steam to the multistage dryer;
A steam circulation fan for circulating steam in the circulation circuit;
A heat exchanger for regenerating superheated steam that regenerates superheated steam by heating steam from a steam circulation fan in the middle of the circulation circuit,
A hot gas generator for supplying hot gas to the heat exchanger for regenerating superheated steam;
A deodorizing device for deodorizing surplus steam in the circulation circuit and supplying it into the hot gas generator;
With an auxiliary boiler that sends steam in the middle of the circulation circuit ,
A superheated steam circulation drying system characterized in that a first valve for supplying or stopping supply of steam generated from an auxiliary boiler is provided in the middle of a circulation circuit . A drainage recovery tank for recovering drain water generated in the multistage dryer or / and in the circulation circuit;
Superheated steam circulating drying system according to claim 1, further comprising a drain water by opening the second valve and a sprayer for spraying a multistage dryer waste water recovery tank. The superheated steam circulation drying system according to claim 2 , wherein the drain water sprayed into the multistage dryer is heated by a heater by exhaust heat of the hot gas generator. A third valve for flowing drain water generated in the multistage dryer or / and the circulation circuit into the waste water recovery tank;
A controller that opens the third valve so as to collect the drain water generated in the multi-stage dryer or / and the circulation circuit in the waste water recovery tank until the temperature in the multi-stage dryer reaches a specific temperature. The superheated steam circulation type drying system according to claim 2 or 3 . When the temperature in the multi-stage dryer reaches a specific temperature before the raw material is charged, the third valve is closed, and after that, the drain in the wastewater collection tank is discharged only when the outlet steam temperature of the multi-stage dryer exceeds the set value. The superheated steam circulation drying system according to claim 4 , wherein water is controlled to be sprayed into the multistage dryer using a sprayer without passing through a heater. An adjustment valve that controls the amount of excess steam introduced into the deodorization device;
A flow control unit for predefining the flow rate of superheated steam in the circulation circuit;
The superheated steam circulation drying system according to any one of claims 1 to 5 , wherein the amount of surplus steam supplied to the hot gas generator through the deodorizing device is controlled by an adjustment valve linked to the flow rate control unit. After stopping the material charging, the first valve is opened, the steam from the auxiliary boiler is supplied to the circulation circuit, the second valve is opened, and the water in the drainage recovery tank is passed through the heater. 4. The superheated steam circulation type drying system according to claim 3, wherein the drying system is adapted to be sprayed into a multi-stage dryer using a sprayer.

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