TW202246189A - 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 invention relates to a sludge dryer, in particular to a sludge dryer with segmental dehumidification and/or segmental heating of circulating air.

The wastewater treatment plant of the factory usually uses a sludge dryer to further dry the sludge produced by the dehydrator, so as to achieve the purpose of sludge reduction and resource recovery or stabilization. In the place 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, including a sludge drying box, a condenser, a heat exchange device, a closed air circulation loop, a waste heat source and a chiller, the closed air circulation The loop connects the sludge drying box, the condenser and the heat exchange device, the waste heat source supplies heat energy to the heat exchange device, and the chiller is used to remove the heat energy generated by the condenser. The closed air circulation sludge dryer can use the low-order waste heat in the factory as the heat source for heating the air, which has the effect 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 source of condensed water for circulating air, which will have another disadvantage of consuming a lot of energy. . In addition, in terms of the use of waste heat in the closed air circulation sludge dryer, the use of a single heat exchanger to heat the circulating air will also limit the selection of waste heat sources, especially the selection of low-order waste heat sources.

Therefore, the main purpose of the present invention is to provide a sludge dryer with staged dehumidification of circulating air. The utilization of recycled cold water and/or waste heat source achieves the effect of energy saving.

The sludge dryer with dehumidification by circulating air in sections of the present invention comprises a sludge drying box, a heater, a post-stage condensing dehumidifier, and a chiller. The sludge drying box provides the storage of the water-containing sludge to be dried, and the sludge will generate humid air after being heated. The heater is connected with the sludge drying box by an air inlet pipeline. The back stage condensing dehumidifier is connected to the sludge drying box with an exhaust pipeline, and the back stage condensing dehumidifier is connected to the heater with a cold air pipeline. The cold air pipeline, the air intake line and The exhaust pipeline forms a closed air circulation loop. The humid air produced by the sludge will be discharged from the exhaust pipeline and flow in the air circulation loop, and will be cooled and dehumidified by the subsequent condensing dehumidifier and the The heater heats up. The ice water machine is connected to the back-stage condensing dehumidifier, and the ice water produced by the ice water machine will flow into the back-stage condensing dehumidifier to exchange heat with the humid air entering the back-stage condensing dehumidifier, so that the humid air is condensed and dehumidified . 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 produces The cold water temperature is higher than the ice water temperature of the ice water machine. The humid air discharged from the sludge drying box will flow through the front-stage condensation dehumidifier before entering the rear-stage condensation dehumidifier, and exchange heat with normal temperature cold water to achieve the effect of staged condensation dehumidification in the closed air circulation loop.

In one embodiment, the temperature of the ice water in the chiller is between 5°C and 17°C, and the temperature of the cold water in the normal temperature cold water source is between 17°C and 35°C.

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 arranged on the cold air pipeline between the rear condensing dehumidifier and the heater, so that the air flowing out of the rear condensing dehumidifier will flow through the heater before entering the heater. The pre-heater 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, 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 recovers the waste heat from the first waste heat source.

Other objectives, 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 will only be an example but not in order to limit the specific embodiment, and with reference to the accompanying drawings, the content of the preferred structure of the present invention is described as follows:

Referring to Fig. 1 and Fig. 2, it shows a sludge dryer 10 according to an embodiment of the present invention with circulating air staged dehumidification, the sludge dryer 10 includes a sludge drying box 12, a heater 14, a rear stage condensation dehumidification Device 16, and a chiller 18. The sludge drying box 12 provides storage of the water-containing sludge 20 to be dried. The heater 14 is connected with the sludge drying box 12 with an air intake pipeline 22, so that the high-temperature dry air heated by the heater 14 can enter the sludge drying box 12 through the air intake pipeline 22 to Take away the moisture of the sludge 20. In this embodiment, the heat energy of the heater 14 is supplied by a waste heat source 24. The waste heat source 24 can be, for example, compressed air discharged from an air compressor or waste heat gas such as high-temperature water vapor, but it can also be other waste heat. energy.

The latter condensing dehumidifier 16 is connected to the sludge drying box 12 with an exhaust pipeline 26 . When the water-containing sludge 20 in the sludge drying box 12 is heated, the high-temperature humid air will be discharged through the exhaust pipeline 26 and then enter the subsequent condensing dehumidifier 16 for condensation. In this embodiment, one end of the exhaust pipeline 26 is connected to the top of the sludge drying box 12 , and one end of the air inlet pipeline 22 is connected to the bottom of the sludge drying box 12 . Furthermore, a cold air pipeline 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 pipeline 28 Warm up on medium heat. The cold air pipeline 28, the air intake pipeline 22 and the exhaust pipeline 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 The latter condensation dehumidifier 16 lowers the temperature and dehumidifies, and the heater 14 heats up the temperature. 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 back-stage condensing dehumidifier 16 to provide condensed water for the back-stage condensing dehumidifier 16 . In a specific embodiment, the ice water machine 18 can produce ice water at 5-17 degrees Celsius, and the ice water will flow through the rear-stage condensing dehumidifier 16 to be separated from the humid air entering the rear-stage condensing dehumidifier 16. Heat exchange, cooling and dehumidifying the humid air into dry low-temperature air.

According to a main feature of the present invention, the sludge dryer 10 further includes a front-end condensing dehumidifier 34, the front-end condensing dehumidifier 34 is arranged on the exhaust pipeline 26 and is located between the rear-end condensing 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 the condensing water for the front-stage condensing dehumidifier 34 . In a specific embodiment, the normal-temperature cold water source 36 is, for example, recycled water or discharged water of general factories or institutions. The temperature of the normal temperature cold water provided by the normal temperature cold water source 36 will vary with the seasons, generally between 17-35 degrees Celsius. The cold water at normal temperature will flow through the front-stage condensing dehumidifier 34 to exchange heat with the moist air entering the front-stage condensing dehumidifier 34 to cool down and dehumidify the humid air. Accordingly, when the humid air discharged from the sludge drying box 12 flows through the front condensing dehumidifier 34 and the rear condensing dehumidifier 16 in sequence, the normal temperature cold water from the normal temperature cold water source 36 will be removed The moisture in the circulating air is high, and the ice water of the ice water machine 18 can remove the moisture in the circulating air with a lower dew point temperature in the latter stage, further reduce the absolute humidity of the circulating air, and achieve the effect of segmental condensation and dehumidification to save energy .

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

According to the sludge dryer 10 of the present invention, the closed air circulation circuit 30 is designed with a front-stage condensation dehumidifier 34 using a cold water source 36 at normal temperature as the condensed water, which can effectively save the traditional use of ice water machines in the closed air circulation circuit. in as a single source of condensed water. Specifically, according to the actual test of the sludge dryer 10 of the present invention, in an embodiment where the condensed water of the hydrous sludge 20 is 200 kg, the condensed water passing through the front-stage condensing dehumidifier 34 is about 92 kg, And the water condensed by this rear stage condensing dehumidifier 16 is about 108 kilograms. Since the normal temperature cold water from 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 condensed water.

Figure 3 and Figure 4 show the second embodiment of the circulating air dehumidification sludge dryer 10 of the present invention, in this embodiment, the sludge dryer 10 further includes a pre-heater 38, the pre-heater 38 is set On the cold air pipeline 28 and between the rear condensing dehumidifier 16 and the heater 14 , the air flowing out of the rear condensing dehumidifier 16 will flow through the pre-heater 38 to heat up before entering the heater 14 . The thermal energy of the pre-heater 38 is supplied by a waste heat source 40, which may be lower temperature low-order waste heat. In one embodiment, the temperature of the waste heat source of the heater 14 is set between 50°C and 99°C, and the temperature of the waste heat source of the pre-heater 38 is set between 30°C and 95°C. Furthermore, in a feasible embodiment, the waste heat source 40 of the pre-heater 38 can recover 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 pre-heater 38 to preheat the circulating air, and the waste heat source with a higher temperature is used as the heat energy of the preheater 38. The thermal energy of the heater 14 is used for reheating the circulating air, so as to achieve the effect of fully utilizing the low-level waste heat of the factory.

The above descriptions are detailed descriptions and drawings of 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 scope of the following patents. The spirit of the scope of patents and the embodiments of similar changes All structures and similar structures shall be included in the present invention.

10: Sludge dryer V12: sludge drying box

14: heater 16: Rear condensing dehumidifier

18: Chiller 20: Sludge

22: Intake pipeline 24: Waste heat source

26: exhaust pipe 28: Cold air pipeline

30: Air circulation circuit 32: fan

34: front condensing dehumidifier 36: Normal temperature cold water source

38: Preheater 40: Waste heat source

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

Fig. 2 shows a schematic diagram of the sludge dryer in Fig. 1 .

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

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

10: Sludge dryer

12: Sludge drying box

14: heater

16: Rear condensing dehumidifier

18: Chiller

22: Intake pipeline

24: Waste heat source

26: exhaust pipe

28: Cold air pipeline

30: Air circulation circuit

32: fan

34: front condensing dehumidifier

Claims (7)

A sludge dryer with staged dehumidification of circulating air, including: A sludge drying box, which provides storage for the water-containing sludge to be dried, and the sludge will generate humid air after being heated; A heater, which is connected with the sludge drying box by an air intake pipeline; A rear-stage condensing dehumidifier, which is connected to the sludge drying box with an exhaust pipeline, and a cold air pipeline is used between the rear-stage condensing dehumidifier and the heater. The cold air pipeline, the air intake pipe The road 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 pipeline to flow in the air circulation loop and sequentially pass through the post-stage condensing dehumidifier to cool down Dehumidification and heating by the heater; An ice water machine, which is connected to the rear-stage condensing dehumidifier, and the ice water produced by the ice water machine will flow into the rear-stage condensing dehumidifier to exchange heat with the humid air entering the rear-stage condensing dehumidifier to condense the humid air 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 higher than the temperature of the ice water of the ice water machine, and the humid air discharged from the sludge drying box will flow through the front condensation dehumidifier before entering the rear condensation dehumidifier, and the normal temperature of the normal temperature cold water source The cold water performs heat exchange to achieve the effect of segmental condensation and dehumidification in the closed air circulation loop. According to the sludge dryer according to item 1 of the patent application, 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. According to the sludge dryer according to item 1 of the scope of patent application, a fan is provided on the air circulation circuit to provide power for air to flow and circulate in the air circulation circuit. The sludge dryer as described in any one of items 1 to 3 of the patent scope of the application, wherein a pre-heater is arranged on the cold air pipeline and is located between the rear-stage condensing dehumidifier and the heater, so that from the rear-stage Air from the condensing dehumidifier passes through the pre-heater to warm it up before entering the heater. The sludge dryer described in item 4 of the scope of patent application, 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 The temperature is lower than the temperature of the first waste heat source. The sludge dryer as described in item 5 of the patent application, wherein the second waste heat source is to recover the waste heat of the first waste heat source. The sludge dryer as described in item 4 of the scope of patent 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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