KR20190031845A - Sludge drying apparatus with electro-dewatering device - Google Patents

Abstract

The present invention relates to a drying apparatus for electrically dewatering sludge and more specifically, to a drying apparatus for electrically dewatering sludge which combines an electrical dewatering unit to conduct direct current electricity in dewatered sludge dewatered by a dewatering unit in a sewage treatment facility or a wastewater treatment facility (hereafter, the sewage treatment plant) to additionally remove water by electrophoresis, and a drying unit and a hot water circulation unit to dry electrically dewatered sludge with hot water produced in an electric dewatering process to cleanly dry dewatered sludge with small energy. The drying apparatus consists of a hot water circulation unit to circulate hot water produced by an electrical dewatering unit and a drying unit capable of quickly heating electrically dewatered sludge with the hot water. Steam and latent heat produced in electrical dewatering and drying processes are collected by a heat pump in front of a deodorizing unit for removing foul odors, and are supplied to the drying unit as drying energy. The dried sludge is made into pellets and dried using the heat pump to be supplied as power plant fuel.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a sludge drying apparatus and an electro-

The present invention relates to a sludge electric dewatering and drying machine, and more particularly, to a sludge electric dewatering and drying machine in which a dewatering sludge dewatered into a dewatering unit is energized in a sewage treatment facility or a wastewater treatment facility The present invention relates to a sludge electric dewatering and drying machine for drying dewatered sludge cleanly with a small energy by combining an electric dewatering unit for removing dewatered water and a drying unit for drying electric dewatering sludge by hot water generated in an electric dewatering process and a hot water circulation unit.

The present invention relates to a drying device comprising a hot water circulating unit for circulating hot water generated in an electric dewatering unit to a drying unit and a drying unit for rapidly heating the hot water electric dewatering sludge, The present invention relates to a sludge electric dewatering and drying machine for supplying latent heat of steam generated in a drying process to a drying unit by supplying a drying energy to a drying unit and drying sludge by pelletizing and drying by using a heat pump.

Dewatered sludge has a moisture content of 80%, which is prohibited from direct landfilling. It is dried or incinerated. In 1,000kg of dehydrated sludge, only 200kg of solid is contained. 800kg of water is contained and more than 100 million fine cells in 1g contain water Since it is difficult to dewater this much water by the machine, it is necessary to heat it with heat energy and dry it. Because it uses more than 1 million kcal dry energy in the process of drying this water, excessive processing cost is incurred. And the treatment facilities cause many complaints.

Electrically dewatering is a technique of dewatering water of dehydrated sludge by electrophoresis in which particles such as protein nucleic acid move from the cathode to the anode by the force of current flow when a direct current flows through the dehydrated sludge, About 500kg of water contained in 1000kg of water is dehydrated, and more than 99% of bacteria that produce odor are killed.

However, in the process of electric dewatering, about 170 kwh or more of electricity is used per 1,000 kg of dewatered sludge, and the electricity used is converted into heat energy to heat the electric drum. When the electric drum is overheated, the electrophoresis is difficult, However, since the heat transfer characteristic of the sludge is poor due to the generation of hot water at 55 ° C, the conventional apparatus can not use the hot water at 55 ° C for drying the sludge, and the hot water is discharged from the sewage treatment plant equipped with the electric dehydrator.

Especially, since most of the hot plates used in conventional dryers use air as a heat transfer medium for drying, the heat transfer of air is significantly lower than the heat transfer of liquid or the heat conduction of solid. Therefore, I can not convey the heat energy properly, so hot water is being abandoned.

However, since the electric dehydrator is expensive and consumes a large amount of electricity, it is incapable of final disposal of the sludge. Therefore, there is a problem of inconvenience and cost inconvenience of carrying the sludge that has been dehydrated electrically to the outside, It is impossible to put it into the existing drying and incineration facilities. Therefore, the electric dehydrator is not used except for the fact that it has no effect other than the 50% reduction in electric dehydration.

Therefore, it is a new hot plate which realizes contact heat conduction which is several tens times faster than the heat transfer of air. By using the drying unit which improved the heat transfer characteristic, it is possible to reduce the energy by drying the electric dewatering sludge by using the hot water of 55 ° C, A sludge drying device that can utilize the sludge as a resource is needed.

SUMMARY OF THE INVENTION The object of the present invention is to provide a method and apparatus for drying sludge in a sewage treatment plant, And a sludge electric dewatering dryer.

Another object of the present invention is to provide a clean and quick sludge electric dewatering and drying machine which is capable of conducting electricity dehydration and drying immediately after discharging dehydrated sludge from a sewage treatment plant, thereby preventing the deodorized sludge from being stale and generating odors.

Another object of the present invention is to provide a sludge electric dewatering and drying machine which recovers latent heat of water vapor generated in an electric dewatering and drying process and utilizes it as drying energy.

Another object of the present invention is to provide a sludge electric dewatering and drying machine which can convert sludge into pellets and utilize the dewatered sludge treated with the waste as a resource of the fuel or fertilizer of the power plant.

According to an aspect of the present invention, there is provided a dewatering unit comprising: a dewatering unit for draining dewatered sludge from a sewage treatment plant; An electric dewatering unit for electrolytically dewatering the water of the dewatered sludge by electrophoresis generated when DC electricity is applied to the dewatered sludge to produce an electric dewatered sludge; A drying unit for drying the electric dewatered sludge with a drying sludge; A hot water circulating unit for circulating the hot water between the electric dewatering unit and the drying unit to supply hot water generated in the electric dewatering unit to the drying unit; A transfer unit connecting the sludge discharge port of the electric dewatering unit and the inlet of the drying unit to transfer the electric dewatered sludge; And connected to the dehydrating unit to dehydrate and dry the dehydrated sludge as soon as the dehydrated sludge is produced.

The hot water circulation unit includes: an electric drum connected to the anode of the galvanic cell in the electric dewatering unit and rotated; An electric drum hot water tank installed on an inner surface of the electric drum; A drum warm water passage through which the hot water formed by the electric drum and the electric drum hot water tank moves; An electric drum rotary joint for supplying and discharging hot water to the drum hot water passage connected to the rotary shaft central passage of the electric drum and rotating; Wherein the drying unit comprises: a rotating cylindrical heating plate of the drying unit; A cylindrical hot plate water heater installed on an outer surface of the cylindrical hot plate; A hot plate hot water passage through which the hot water formed by the cylindrical hot plate and the cylindrical hot plate hot water tank moves; A cylindrical rotary plate rotary joint for supplying and discharging hot water from the hot plate hot water passage connected to the rotary shaft central passage of the cylinder and rotating; A wheel supporting the outside of the hot plate water passage so that the cylindrical hot plate rotates; The hot water heated and discharged in the electric dewatering process in the electric drum is directly supplied to the cylindrical hot plate and hot water circulated through which the hot water discharged from the cooling hot plate is supplied to the electric drum .

The electric dewatering sludge is dried in the cylindrical heat plate while the heat transfer material is mixed with the electric dewatering sludge.

A deodorizing unit for removing the odorous substances generated in the electric dewatering unit and the drying unit together; A condensing unit for removing water vapor contained in the air discharged from the electric dewatering unit or the drying unit in front of the deodorizing unit; Wherein the condensing unit includes a heat pump cooler for condensing the steam into condensed water and cooling the air to absorb the latent heat of the steam into the coolant; A heat pump hot water heat radiating latent heat absorbed by the refrigerant to heat the hot water; And supplies the latent heat absorbed while removing the steam to the drying unit.

A molding unit for molding the dried sludge discharged from the drying unit into pellets; A pellet drying unit for drying the pellet; And a heat pump is included in the pellet drying unit to absorb the latent heat of the water vapor discharged in the pellet drying process and is used as drying energy to dry the pellets to a moisture content of 10% or less.

The sludge electric dewatering and drying apparatus according to the present invention improves the heat transfer characteristics of the drying unit by using a rotating cylindrical heating plate and a heat transfer material to make 1,000 kg of dewatered sludge into 220 kg of clean dry pellets And also greatly reduces the processing cost.

The sludge electric dewatering and drying apparatus according to the present invention connects the electric dewatering unit and the drying unit to dry the dewatered sludge immediately after drying to prevent the occurrence of decay and to condense the water vapor and the odor substances discharged together with the air into a cooler using a heat pump, It is advantageous to remove the odorous substances while recovering the latent heat.

The sludge electric dewatering and drying apparatus according to the present invention recovers heat energy generated by electric dewatering as dry energy and absorbs the heat of sewage by a heat pump to use as drying energy so that 1,000 kg of dewatered sludge having a water content of 80% The conventional technology uses a drying energy of 1 million kcal or more, whereas the present invention uses 240 kwh of electricity (200,000 kcal or less), which is advantageous in energy efficiency five times or more than the existing technology.

Since the dry sludge dewatering dryer according to the present invention is dried immediately after dewatering, the dry pellet in a clean state without odor is made to have a final water content of 10% or less and supplied as fuel or fertilizer of a power plant. Therefore, dewatered sludge of a sewage treatment plant is utilized as resources There is an advantage.

1 is a configuration diagram of a sludge electric dewatering and drying apparatus according to the present invention.
2 is a cross-sectional view of a cylindrical hot plate rotating inside the drying unit;
Fig. 3 is a configuration diagram of a drying unit in which the cylindrical heat plates are even-numbered.
4 is a configuration diagram of a sludge electric dewatering and drying machine equipped with a condensing unit.
5 is a configuration diagram of the pellet drying unit.
6 is a cross-sectional view illustrating the operation principle of the electric dewatering unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a sludge electric dewatering and drying apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view of a sludge electric dewatering and drying apparatus according to the present invention. Referring to FIG. 1, a dewatering sludge 10 to be introduced into an electric dewatering unit 100 is first dewatered to a dewatering unit at a sewage treatment plant, Is between 70% and 85%, but the water content is assumed to be 80% for the purpose of the present invention.

1,000 kg of dehydrated sludge with a water content of 80% has a solid content of 200 kg and contains 800 kg of water, so that it can be decayed quickly. Since it is no longer removed by mechanical force, it is necessary to evaporate heat by removing heat. Theoretically, The evaporation energy of 540 kcal is needed to evaporate 780 kg of heat energy to make dry sludge having a moisture content of less than 10%. However, actual dehydrated sludge is composed of more than 100 million fine cells per gram, which prevents water migration and evaporation due to numerous cell membranes and osmotic pressure. Therefore, in the actual drying process, drying energy more than twice the theoretical energy of 1 million kcal And a dryer that uses more than 2 million kcal energy.

In addition, when the dehydrated sludge is discharged from the dehydration unit, the deodorization begins. When the dehydrated sludge is discharged at a room temperature for more than 2 hours, the deodorizing sludge starts to be generated. Generally, In the process of storage, transportation and drying, extreme odor is emitted and the drying facility is recognized as a dislike facility and causes many complaints.

In the present invention, the electric dewatering unit 100 and the drying unit 200 are connected to each other so that drying can be performed immediately after the dewatering sludge 10 is discharged from the dewatering unit (not shown) 500 kg of 800 kg of water contained in the dewatered sludge was removed by electrophoresis of the dewatered sludge 10 by electrophoresis of 170 kwh to make 500 kg of the dewatered sludge 20 which was sterilized by 99% To the drying unit (200).

The hot water circulating unit 300 of the present invention is composed of a pump 310 and a connecting pipe as a hot water moving path circulating between the electric dewatering unit 100 and the drying unit 200, The movement of hot water is indicated.

The electric drum 120 is heated to about 100,000 kcal in thermal energy of 140,000 kcal generated by electricity of 170 kwh consumed in the electric dehydration process so that the electric drum 120 is heated in the electric drum 120 Hot water of 45 ° C is supplied to the drum warm water passage 130 formed with the drum warm water tank 135 via the electric drum rotary joint 110 and the drum warm water passage inlet 131, And hot water of 55 ° C is discharged via the drum rotary joint 110 to cool the electric drum 120.

A hot water channel 220 is connected to the outside of the cylindrical hot plate 210 provided inside the drying unit 200 to supply hot water of 55 ° C discharged from the electric dewatering unit 100 to the drying unit 200, The electric water dewatering sludge which is in contact with the cylindrical heating plate in the cylindrical heating plate which heats the cylindrical heating plate 210 by moving hot water is quickly heated and absorbs the vaporization energy while water evaporates into water vapor, The hot water coming out of the electrolytic unit 100 is cooled to 45 ° C and circulated back to the electrolytic dehydration unit 100.

The hot water circulating unit 300 requires 10,000 liters of hot water to transfer 100,000 kcal using a temperature difference of 10 DEG C. The electric drum rotary joint 110 and the cylindrical hot plate rotary joint 250, a pump 310 and a pipe are installed to circulate hot water between the electric dewatering unit 100 and the drying unit 200.

When the electric dewatering sludge 20 is immediately put into the drying unit 200 and dried using the heat of 100,000 kcal transmitted from the electric dewatering unit 100, 150 kg of water can be dried, And 350 kg of the dried sludge 30 is discharged into the tank 31.

Since the dried sludge is dried immediately after dehydration and drying, it is not corroded at all and it does not cause bad odor. Therefore, it can be used as resources such as fertilizer instead of waste, and the amount of external transportation is greatly reduced from 1000 kg to 350 kg.

Particularly, in order to make it possible to dry using the 55 ° C hot water, the heat transfer ability of the drying unit 200 must be ensured. In the conventional heat plate, the heat plate conveys heat to the air, Air heat transfer is required, but air heat transfer is too low to use 55 ° C hot water.

In order to solve this problem, a new heating plate is developed in order to realize heat conduction due to contact between solids which is several tens of times higher than the heat transfer of air, so that the electric dewatering sludge and the heating plate are in direct contact with each other in the rotating cylindrical heating plate 210 And the heat transfer material 201 made of a metal is added together with the electric dewatering sludge to increase the heat transfer rate by adding contact heat conduction.

FIG. 2 shows a structure for enhancing the heat transfer capability of the cylindrical heat plate 210 so that the cylindrical heat plate 210 can rapidly heat the electric dewatered sludge. The inner heat exchanger 240 has a plurality of inner bases 240 and a plurality of screw plates 241 The electric dewatered sludge 20 which is in contact with the rotating cylindrical heating plate 210 when the electric dewatered sludge 20 is put into the cylindrical heating plate 210 is returned to the inner base 240 of the rotating cylindrical heating plate 210, And is moved upward by the screw plate 241 from the inlet of the cylindrical heating plate 210 to the outlet of the cylindrical heating plate 210 to be contacted with the cylindrical heating plate 210 to be rapidly heated and dried.

In this process, the heat transfer material 201 having a thermal conductivity tens of times higher than that of the electric dewatering sludge 20 is heated much faster while being in contact with the cylindrical heat plate 210, so that the heated heat transfer material 201 is mixed with the electric dewatered sludge 20 The contact area is greatly increased and the electric dewatering sludge 20 is heated and dried quickly.

The shape of the heat transfer material 201 is formed into a cylindrical or spherical shape so as to be in contact with the inner surface while rolling inside the rotating cylindrical heat plate 210. When the apparent specific gravity of the heat transfer material 201 is made similar to that of the electric dewatered sludge, The material 201 and the electric dewatering sludge 20 are made to contact each other without being separated.

Since the electric dewatering sludge 20 and the heat transfer material 201 are continuously rotated and contacted with each other while rolling in the cylindrical heating plate 210 rotating in this manner, the fixed temperature of the electric dewatering sludge 20 A discontinuity surface or an air insulating layer is not formed, and no deformation that interferes with heat transfer is generated, so that drying is performed quickly.

A cylindrical hot plate water warming tank 230 for forming a cylindrical hot water passage 220 on the outer side of the cylindrical hot plate 210 to heat the rotating cylindrical hot plate 210 with hot water is provided and the hot water passage inlet 221, And the hot water passage outlet 222 are connected to the rotating part of the cylindrical rotary joint 250 and the fixed hot water supply pipe 251 and the hot water discharge pipe 252 connected to the outside are connected to the fixed part of the rotary rotary joint 250 The hot water supplied from the electric dewatering unit 100 supplies dry energy to the cylindrical hot plate 210 through the cylindrical hot water passage 220 of the rotating cylindrical hot plate 210.

3 shows an embodiment in which two cylindrical heat plates 210 are installed in an even number in the drying unit 200. In the case of constituting an even number of cylindrical heat plates 210 and an odd number of cylindrical heat plates 210, (30) can be arranged differently depending on the site conditions. Also, the outer surface of the cylindrical hot-plate hot-water tank 230 is rotated by supporting the outer surface of the cylindrical hot-plate hot-water tank 230 by means of the wheel 260. Various devices for supporting the rotating cylindrical hot-

FIG. 4 shows a condensing unit 400 added to the embodiment of FIG. 1, wherein water vapor and odorous substances generated in the electric dewatering unit 100 and the drying unit 200 are mixed with air and mixed before being discharged into the deodorizing unit. It is composed of a heat pump that uses the heat pump to remove the latent heat of the steam and make hot water to remove the odor and supply the drying energy. The refrigerant movement (hollow triangle), water vapor movement (black arrow) and hot water movement Empty arrow).

When the refrigerant in the heat pump is compressed by the compressor 410, the refrigerant gas of high temperature and high pressure is discharged from the refrigerant condenser 420 at a high temperature to be converted into a liquid of low temperature and high pressure, The refrigerant absorbs energy at a low temperature in the refrigerant evaporator 440, changes into a low-temperature and low-pressure gas, and then returns to the compressor 410 to circulate.

The water vapor is mixed with the odorous substance and mixed with the air so that the water vapor discharged from the dewatering exhaust port 190 of the electric dewatering unit 100 and the dry exhaust port 290 of the drying unit 200 flows through the cooling inlet port 462 of the cooler 460 The condensed water is condensed into condensed water while most of the odorous substances are removed together and the air that is discharged to the condensed water discharge port 463 is discharged to the outside of the cool outlet 461 through the cooling outlet 461, (Not shown) to remove the material.

The hot water movement in the condensing unit 400 absorbs the latent heat and compresses the gas refrigerant into the compressor 410 and discharges the latent heat in the refrigerant condenser 420 of the hot water heater 450, The hot water is heated to 55 ° C and discharged to the hot water outlet 451 to supply the hot water to the cylindrical hot water passage 220 of the drying unit 100 and circulate the hot water using the condensing unit pump 470.

The condensing unit 400 recovers the latent heat of the steam and supplies it as dry energy to further dry 70 kg of water. Since the heat efficiency of the heat pump is 3 times higher than that of the heat pump, when the electricity of about 30 kwh is used, 720 kg of water is dried in 1000 kg of dehydrated sludge with a total of 200 kwh of electric power consumed and 280 kg of dried sludge having a moisture content of 28.6% is obtained when only 80 kg of water remains in the dried sludge and contains 200 kg of solid content.

The water content of about 30% which is suitable for molding into pellets which can be used as a fuel or fertilizer of a power plant is suitable for molding, and a molding unit (not shown) for molding pellets can be easily purchased in the market, .

5 shows a pellet drying unit 500. The pellet drying unit 500 is a combination of the drying unit 200 and the condensing unit 400 described above. The pellet is charged into the drying unit 200 instead of the electric dehydrating sludge Except for the difference that the dry pellets are discharged in place of the dry sludge, the same device is not described in detail.

Since the pellet generates heat in the molding process, the moisture content of the pellet is about 30%, and the moisture content of the pellet is about 20%. Therefore, in order to make the water content of the fuel in the pellet less than 10% 25 kg of water is removed by drying. Because the pellet molding and drying requires about 40 kwh of electricity, a total of 240 kwh of electricity is required to make 1,000 kg of dewatered sludge into 220 kg of dry pellets, which greatly reduces energy compared to conventional dryers.

6 is a sectional view showing the operation principle of the electric dewatering unit. Briefly, the electric dewatering unit 100 includes a rotating electric drum 120 and a caterpillar 140 rotating along at least a part of the outer circumferential surface of the electric drum. A moving belt 160 for moving the sludge 10 between the electric drum and the caterpillar and a power applying unit 180 for applying electricity to the electric drum 120 and electricity to the caterpillar 140 And a slip ring 181 for transferring electricity to the electric drum 120. The electric motor 140 rotates the caterpillar supporting roller 150 by a motor (not shown) while supplying DC electricity to the rotating electric drum and the caterpillar, When the dewatered sludge 10 is injected between the cathode 120 and the caterpillar 140, electrons move from the cathode to the anode and electrophoresis moves the protein particles to collect particles in the cathode drum, The water remained in Caterpillar done dehydration.

The electric drum 120 is rotated by the caterpillar 140 and the moving belt 160 serving as a dehydrating filter cloth travels in an endless track between the electric drum 120 and the caterpillar 140 while the electric drum 120 and the caterpillar 140 The rotation of the moving belt 160 is guided by the guide rollers 170 while the dewatering sludge 10 is introduced and moved and dewatered and the electric dewatering sludge 20 is discharged.

As described above, the present invention is not limited to the above-described specific preferred embodiments, and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention as claimed in the claims. And such variations are within the scope of the present invention.

10: dehydrated sludge 20: electric dehydrated sludge
30: Drying sludge 60: Heat transfer material
100: electric dewatering unit 110: electric drum rotary joint
120: electric drum 130: drum hot water passage
200: drying unit 210: cylindrical heating plate
220: cylindrical hot water passage 250: cylindrical hot plate rotary joint
300: hot water circulation unit 310: pump
400: condensing unit 450: hot water heating
460: cooler 470: condensing unit pump
500: pellet drying unit

Claims (5)

A dewatering unit for draining the dewatered sludge from the sewage treatment plant;
An electric dewatering unit for electrolytically dewatering the water of the dewatered sludge by electrophoresis generated when DC electricity is applied to the dewatered sludge to produce an electric dewatered sludge;
A drying unit for drying the electric dewatered sludge with a drying sludge;
A hot water circulating unit for circulating the hot water between the electric dewatering unit and the drying unit to supply hot water generated in the electric dewatering unit to the drying unit;
A transfer unit connecting the sludge discharge port of the electric dewatering unit and the inlet of the drying unit to transfer the electric dewatered sludge; Consist of
And a dewatering unit connected to the dewatering unit to dehydrate and dry the dewatered sludge as soon as it is generated. The method according to claim 1,
The hot water circulation unit
An electric drum connected to the anode of the direct current in the electric dewatering unit and rotated;
An electric drum hot water tank installed on an inner surface of the electric drum;
A drum warm water passage through which the hot water formed by the electric drum and the electric drum hot water tank moves;
An electric drum rotary joint for supplying and discharging hot water to the drum hot water passage connected to the rotary shaft central passage of the electric drum and rotating; Made of
The drying unit
A rotating cylindrical heating plate of the drying unit;
A cylindrical hot plate water heater installed on an outer surface of the cylindrical hot plate;
A hot plate hot water passage through which the hot water formed by the cylindrical hot plate and the cylindrical hot plate hot water tank moves;
A cylindrical rotary plate rotary joint for supplying and discharging hot water from the hot plate hot water passage connected to the rotary shaft central passage of the cylinder and rotating;
A wheel supporting the outside of the hot plate water passage so that the cylindrical hot plate rotates; It consists
Wherein the hot water heated and discharged in the electric dewatering process is supplied to the cylindrical hot plate and hot water circulated through which the hot water discharged from the cooling hot plate is supplied to the electric drum is transferred through the cylindrical hot plate Sludge electric dehydrator dryer. 3. The method of claim 2,
And a heat transfer material is mixed with the electric dewatering sludge while the electric dewatering sludge is dried in the inside of the cylindrical heat plate. The method according to claim 1,
A deodorizing unit for removing the odorous substances generated in the electric dewatering unit and the drying unit together;
A condensing unit for removing water vapor contained in the air discharged from the electric dewatering unit or the drying unit in front of the deodorizing unit; Is installed
The condensing unit
A heat pump cooler for condensing the steam into condensed water and cooling the air to absorb the latent heat of the steam into the coolant;
A heat pump hot water heat radiating latent heat absorbed by the refrigerant to heat the hot water; It consists
And the latent heat absorbed while removing the steam is supplied to the drying unit. The method according to any one of claims 1 to 4,
A molding unit for molding the dried sludge discharged from the drying unit into pellets;
A pellet drying unit for drying the pellet; And install
Wherein a heat pump is included in the pellet drying unit to absorb the latent heat of the water vapor discharged in the pellet drying process and to use the pellet as drying energy to dry the pellet to a moisture content of 10% or less.

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