TWI756135B - Sludge dryer capable of dehumidifying circulating air in stages - Google Patents

Abstract

A sludge dryer capable of dehumidifying circulating air in stages comprises a sludge drying box, a heater, a rear-stage condensation dehumidifier and an ice water machine. The sludge drying box stores the water-containing sludge to be dried. The heater and the sludge drying box are connected by an air inlet pipe. The rear-stage condensation dehumidifier and the sludge drying box are connected by an exhaust pipe, and the rear-stage condensation dehumidifier and the heater are connected by a cold air pipe. The cold air pipe, the air inlet pipe and the exhaust pipe form a closed air circulation loop. The ice water produced by the ice water machine will flow into the rear-stage condensation dehumidifier to exchange heat with moist air entering the rear-stage condensation dehumidifier. It is characterized in that a front-stage condensation dehumidifier is arranged on the exhaust pipe and located between the rear-stage condensation dehumidifier and the sludge drying box, and the front-stage condensation dehumidifier is connected to a normal temperature cold water source. The moist air discharged from the sludge drying box will exchange heat with the cold water of the normal temperature cold water source before entering the rear-stage condensation dehumidifier to achieve the effect of staged condensation and dehumidification.

Description

Sludge dryer with staged dehumidification of circulating air

The present invention relates to a sludge dryer, in particular to a sludge dryer with dehumidification and/or heating in stages of circulating air.

The wastewater treatment plant of the factory usually uses a sludge dryer to further dry the sludge produced by the dewatering machine to achieve the purpose of sludge reduction and resource utilization or stabilization. In places where there is waste heat in the factory, if the waste heat is used to heat the air of the drying medium and then use ice water to condense and dehumidify the moisture brought out by the drying medium through the sludge drying bed, the purpose of closed air circulation sludge drying can be achieved. Invention patent I458926 discloses a closed air circulation sludge dryer, which includes a sludge drying box, a condenser, a heat exchange device, a closed air circulation loop, a waste heat heat source and an ice water machine. The closed air circulation The circuit connects the sludge drying box, the condenser and the heat exchange device, the waste heat heat source supplies heat energy to the heat exchange device, and the ice water machine is used for removing the heat energy generated by the condenser. The closed air circulation sludge dryer can use the low-level waste heat in the factory as a heat source for heating air, and has the effects of saving energy and cooling the waste heat. However, the ice water machine needs a lot of energy in the process of making ice water. Therefore, the closed air circulation sludge dryer uses ice water below 17°C as the only condensed water source for circulating air, which will have another shortage of energy consumption. . In addition, in the use of waste heat in the closed air circulation sludge dryer, the use of a single heat exchanger to heat the circulating air also limits the selection of waste heat sources, especially the selection of low-level waste heat sources.

Therefore, the main purpose of the present invention is to provide a sludge dryer with staged dehumidification of circulating air, which allows staged dehumidification and/or staged heating of circulating air in a closed air circulation loop, so as to be more efficient. The use of recycled cold water and/or waste heat sources to achieve energy saving effect.

The sludge dryer for dehumidification by stage of circulating air of the present invention comprises a sludge drying box, a heater, a rear-stage condensation dehumidifier, and an ice water machine. The sludge drying box provides storage of aqueous sludge to be dried, and the sludge will generate moist air when heated. The heater and the sludge drying box are connected by an air inlet pipeline. The rear condensing dehumidifier and the sludge drying box are connected by an exhaust pipeline, and the rear condensation dehumidifier and the heater are connected by a cold air pipeline. The cold air pipeline, the intake pipeline and the The exhaust pipeline forms a closed air circulation loop, and the humid air generated by the sludge will be discharged from the exhaust pipeline to flow in the air circulation loop and sequentially pass through the condensing dehumidifier at the rear stage to cool down and dehumidify and the Heater heats up. The chiller is connected to the rear condensing dehumidifier, and the ice water generated by the chiller will flow into the rear condensation dehumidifier to exchange heat with the humid air entering the rear condensation dehumidifier to condense and dehumidify the humid air. . It is characterized in that a front-stage condensing dehumidifier is arranged on the exhaust pipeline and between the rear-stage condensing dehumidifier and the sludge drying box, the front-stage condensing dehumidifier is connected to a normal temperature cold water source, and the normal temperature cold water source produces The cold water temperature is greater than the ice water temperature of the chiller. The humid air discharged from the sludge drying box will flow through the front-stage condensing dehumidifier before entering the rear-stage condensing dehumidifier, and conduct heat exchange with normal temperature cold water to achieve the effect of staged condensation and dehumidification in a closed air circulation loop.

In one embodiment, the temperature of the ice water of the ice water machine is between 5-17 degrees Celsius, and the temperature of the cold water of the normal temperature cold water source is between 17-35 degrees Celsius.

In one embodiment, a fan is provided on the air circulation circuit to provide power for circulating air to flow in the air circulation circuit.

In one embodiment, a pre-heater is provided on the cold air pipeline and between the rear condensing dehumidifier and the heater, so that the air flowing out from the rear condensing dehumidifier will flow through the heater before entering the heater. The preheater heats up.

In one embodiment, the heat energy of the heater is supplied by a first waste heat source, the heat energy of the pre-heater is supplied by a second waste heat source, and the temperature of the second waste heat source is lower than the temperature of the first waste heat source .

In one embodiment, the second waste heat source recycles waste heat from the first waste heat source.

Other objects, advantages and features of the present invention will be understood from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

Now it is only an example but not a specific embodiment for limitation, and with reference to the accompanying drawings, the preferred structural content of the present invention is described as follows:

Referring to FIG. 1 and FIG. 2, a sludge dryer 10 for dehumidifying circulating air in stages according to an embodiment of the present invention is shown. The sludge dryer 10 includes a sludge drying box 12, a heater 14, and a rear-stage condensation dehumidification 16, and an ice water machine 18. The sludge drying box 12 provides storage of the aqueous sludge 20 to be dried. The heater 14 and the sludge drying box 12 are connected by an air intake line 22 , so that the high temperature drying air heated by the heater 14 will enter the sludge drying box 12 through the air intake line 22 to The moisture of the sludge 20 is taken away. In this embodiment, the heat energy of the heater 14 is supplied by a waste heat source 24. The waste heat source 24 may be, for example, compressed air discharged from an air compressor or waste heat gas such as high-temperature water vapor, but may also be other waste heat energy.

The rear-stage condensing dehumidifier 16 and the sludge drying box 12 are connected by an exhaust pipe 26 . When the water-containing sludge 20 in the sludge drying box 12 is heated, the high-temperature humid air is discharged through the exhaust pipe 26 and enters the condensing dehumidifier 16 at the rear stage to be condensed. In this embodiment, one end of the exhaust line 26 is connected to the top of the sludge drying box 12 , and one end of the air intake line 22 is connected to the bottom of the sludge drying box 12 . Furthermore, a cold air line 28 is connected between the rear-stage condensing dehumidifier 16 and the heater 14 , so that the low-temperature dry air cooled and dehumidified by the rear-stage condensing dehumidifier 16 will enter the heater 14 through the cold air line 28 . Heat up in heating. The cold air line 28 , the intake line 22 and the exhaust line 26 form a closed air circulation loop 30 , so that the humid air generated by the sludge 20 can flow in the air circulation loop 30 and pass through the air circulation loop 30 in sequence. The rear-stage condensing dehumidifier 16 cools and dehumidifies and the heater 14 heats up. In addition, a fan 32 is provided in the air circulation circuit 30 to provide power for the air to flow and circulate in the air circulation circuit 30 . In this embodiment, the fan 32 is provided on the exhaust pipe 26 .

The chiller 18 is connected to the rear condensing dehumidifier 16 to provide condensing water for the rear condensing dehumidifier 16 . In a specific embodiment, the ice water machine 18 can generate ice water at a temperature of 5-17 degrees Celsius, and the ice water will flow through the rear-stage condensing dehumidifier 16 and interact with the humid air entering the rear-stage condensing and dehumidifier 16. The heat exchange makes the humid air cool and dehumidify into dry low temperature air.

According to a main feature of the present invention, the sludge dryer 10 further includes a front-stage condensing dehumidifier 34, and the front-stage condensing dehumidifier 34 is arranged on the exhaust line 26 and located between the rear-stage condensing and dehumidifier 16 and the Between the sludge drying boxes 12 and the front-stage condensing dehumidifier 34 is connected to a normal temperature cold water source 36 to provide condensing water for the front-stage condensing and dehumidifier 34 . In a specific embodiment, the normal temperature cold water source 36 is, for example, recycled water or runoff water of a general factory or business unit. The temperature of the normal temperature cold water provided by the normal temperature cold water source 36 varies with seasons, and is generally between 17-35 degrees Celsius. The cold water at room temperature will flow through the front-stage condensing dehumidifier 34 to exchange heat with the humid air entering the front-stage condensing and dehumidifier 34, thereby cooling and dehumidifying the humid air. Accordingly, when the humid air discharged from the sludge drying box 12 flows through the front-stage condensing dehumidifier 34 and the rear-stage condensing dehumidifier 16 in sequence, the normal temperature cold water of the normal temperature cold water source 36 will remove the dew point of the front stage. The high moisture content of the circulating air, and the ice water of the ice water machine 18 can remove the moisture of the circulating air with a lower dew point temperature in the rear section, further reducing the absolute humidity of the circulating air, and achieving the effect of staged condensation and dehumidification to save energy consumption .

In the implementation of the sludge dryer 10 according to the first embodiment of the present invention, as shown by the arrows in FIG. 2 , the waste heat source 24 is used to provide heat energy to the heater 14 , and the circulating air flowing through the heater 14 will be heated to contain The high-temperature dry air with low water volume will enter the sludge drying box 12 through the intake line 22 to take away the moisture of the sludge 20, and become medium-temperature humid air and be discharged from the intake line 22 Then, the humid air at this middle temperature will flow into the front section condensing dehumidifier 34 to exchange heat with the normal temperature cold water of the normal temperature cold water source 36 and be condensed and dehumidified and part of the humid air will condense to form water droplets; then, from the front section condensation dehumidifier The air flowing out of 34 will flow into the rear condensing dehumidifier 16 to exchange heat with the ice water of the ice water machine 18 and be condensed and dehumidified to become low-temperature dry air; The cold air pipeline 28 flows into the heater 14 and is heated to become high-temperature dry air, and then sent into the sludge drying box 12 for recycling.

The sludge dryer 10 according to the present invention is designed with a front-stage condensing dehumidifier 34 using a normal temperature cold water source 36 as the condensed water in the closed air circulation loop 30, which can effectively save the traditional use of ice water machines in the closed air circulation loop. energy as a single condensate. Specifically, according to the actual test of the sludge dryer 10 of the present invention, in an embodiment where the condensed water of the water-containing sludge 20 is 200 kg, the water condensed by the front-stage condensation dehumidifier 34 is about 92 kg, The water condensed by the rear-stage condensing dehumidifier 16 is about 108 kg. Since the normal temperature cold water of the normal temperature cold water source 36 does not require energy consumption, the sludge dryer 10 of the present invention can save about half of the energy used for condensation and dehumidification compared with the conventional sludge dryer using an ice water machine as a single condensate.

3 and 4 show the sludge dryer 10 for dehumidifying the circulating air in stages according to the second embodiment of the present invention. In this embodiment, the sludge dryer 10 further includes a pre-heater 38, and the pre-heater 38 is provided with The cold air pipeline 28 is located between the rear condensing dehumidifier 16 and the heater 14 , so that the air flowing out from the rear condensing dehumidifier 16 will flow through the preheater 38 to be heated and heated before entering the heater 14 . The thermal energy of the pre-heater 38 is supplied by a waste heat source 40, which may be low-level waste heat at a relatively low temperature. In one embodiment, the temperature of the waste heat source of the heater 14 is set between 50 and 99 degrees Celsius, and the temperature of the waste heat source of the pre-heater 38 is set between 30 and 95 degrees Celsius. Furthermore, in a possible embodiment, the waste heat source 40 of the pre-heater 38 can recycle the waste heat of the waste heat source 24 of the heater 14 . According to this embodiment, the sludge dryer 10 can use one or more waste heat sources, wherein the waste heat source with a lower temperature is used as the heat energy of the preheater 38 to preheat the circulating air, and the waste heat source with a higher temperature is used as the heat energy for preheating the circulating air. The heat energy of the heater 14 is used to reheat the circulating air, so as to fully utilize the low-level waste heat of the factory.

The above are the detailed descriptions and drawings of the preferred embodiments of the present invention, and are not intended to limit the present invention. The entire scope of the present invention should be based on the following patent scope. and similar structures should be included in the present invention.

10: Sludge dryer 12: Sludge drying box

14: Heater 16: Rear condensing dehumidifier

18: Ice water machine 20: Sludge

22: Intake pipeline 24: Waste heat source

26: Exhaust line 28: cold air pipeline

30: Air circulation loop 32: Fan

34: Front condensing dehumidifier 36: Room temperature cold water source

38: Preheater 40: Waste heat source

FIG. 1 is a block diagram of a sludge dryer for dehumidifying circulating air in stages according to the first embodiment of the present invention.

FIG. 2 shows a schematic diagram of the sludge dryer of FIG. 1 .

FIG. 3 is a block diagram of a sludge dryer for dehumidifying circulating air in stages according to the second embodiment of the present invention.

FIG. 4 shows a schematic diagram of the sludge dryer of FIG. 3 .

10: Sludge dryer

12: Sludge drying box

14: Heater

16: Rear condensing dehumidifier

18: Ice water machine

22: Intake pipeline

24: Waste heat source

26: Exhaust line

28: cold air pipeline

30: Air circulation loop

32: Fan

34: Front condensing dehumidifier

Claims (7)

A sludge dryer with dehumidification in stages by circulating air, comprising: a sludge drying box, which provides storage of water-containing sludge to be dried, and the sludge will generate moist air when heated; a heater, which is connected with the sludge drying box by an air inlet pipeline; A rear-stage condensing dehumidifier is connected with the sludge drying box by an exhaust pipeline, and a cold air pipeline is connected between the rear-stage condensing dehumidifier and the heater. The cold air pipeline, the air intake pipe The air circuit and the exhaust pipeline form a closed air circulation loop, in which the humid air generated by the sludge will be discharged from the exhaust pipe and flow in the air circulation loop and sequentially cool down through the condensing dehumidifier at the rear stage. dehumidification and heating by the heater; An ice water machine, which is connected to the rear condensing dehumidifier, and the ice water generated by the ice water machine will flow into the rear condensation dehumidifier to exchange heat with the humid air entering the rear condensation dehumidifier, so that the humid air condenses dehumidification; It is characterized in that a front-stage condensing dehumidifier is arranged on the exhaust pipeline and is located between the rear-stage condensing dehumidifier and the sludge drying box, and the front-stage condensing dehumidifier is connected to a normal temperature cold water source, and the normal temperature cold water source generates The temperature of the cold water is greater than the temperature of the ice water of the ice water machine, wherein the humid air discharged from the sludge drying box will flow through the front condensing dehumidifier before entering the condensing dehumidifier in the rear section, and is different from the normal temperature of the normal temperature cold water source. The cold water conducts heat exchange to achieve the effect of staged condensation and dehumidification in the closed air circulation loop. According to the sludge dryer of claim 1, the temperature of the ice water of the ice water machine is between 5-17 degrees Celsius, and the temperature of the cold water of the normal temperature cold water source is between 17-35 degrees Celsius. The sludge dryer according to claim 1, wherein a fan is arranged on the air circulation circuit to provide power for air to flow and circulate in the air circulation circuit. The sludge dryer according to any one of claims 1 to 3, wherein a pre-heater is arranged on the cold air pipeline and is located between the condensing dehumidifier and the heater in the rear section, so that from the rear section The air from the condensing dehumidifier will flow through the pre-heater to heat up before entering the heater. The sludge dryer as claimed in claim 4, wherein the heat energy of the heater is supplied by a first waste heat source, the heat energy of the pre-heater is supplied by a second waste heat source, and the second waste heat source is less than the temperature of the first waste heat source. The sludge dryer as described in claim 5, wherein the second waste heat source recycles the waste heat of the first waste heat source. The sludge dryer according to item 4 of the scope of application, wherein the temperature of the waste heat source of the heater is set between 50 and 99 degrees Celsius, and the temperature of the waste heat source of the pre-heater is set between 30 and 95 degrees Celsius. .

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