KR102643341B1 - Sludge drying apparatus with waste heat recovery type foe odor removal and energy saving - Google Patents

Abstract

The present invention relates to a waste heat recovery type sludge drying device which reduces the use of fossil fuels by thermally decomposing generation gas and exhaust gas generated in a process of drying organic waste and then recycling them in drying the organic waste, thereby reducing carbon dioxide and reduces environmental pollution by removing odor and water vapor before discharging. In particular, the present invention relates to a waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy which supplies circulated generation gas and exhaust gas to a low-temperature plasma device when the heater is in operation to remove tar components and odorous substances contained in the generation gas, thereby preventing the heater from being polluted and stops the burner and operates only the heater to save energy and minimize the generation of greenhouse gases.

Description

Waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy {SLUDGE DRYING APPARATUS WITH WASTE HEAT RECOVERY TYPE FOE ODOR REMOVAL AND ENERGY SAVING}

The present invention relates to a drying device for drying organic waste. More specifically, the present invention relates to a drying device for drying organic waste. More specifically, the gas generated in the process of drying organic waste is pyrolyzed and recycled to dry the organic waste, thereby reducing the use of fossil fuels and reducing carbon dioxide. This relates to a waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy by reducing environmental pollution by removing odor and water vapor and then discharging it.

Generally, in sewage treatment processes such as the activated sludge process, raw sludge in the initial settling tank and waste sludge in the final settling basin are generated, and some of the excess sludge is used to maintain an appropriate microbial concentration in biological reactors such as aeration tanks. It is used to return for.

In addition, when a chemical phosphorus removal process is introduced for advanced treatment, coagulation and sedimentation sludge containing coagulant components such as aluminum salts is generated. In addition, impurities on the screen, soil and sediment deposited in the silt basin, and scum accumulated on the water surface of the aeration tank are also included in sewage sludge in a broad sense.

Even sewage sludge generated through the dehydration process at a sewage treatment plant contains about 80% water on average. Therefore, since there is no economical way to remove this water, it is mainly dumped in the ocean. If ocean dumping is banned in the future, it will become difficult to treat sewage sludge, or landfill or incineration will have to be done, but even in this case, it costs more than ocean dumping and securing a landfill site is difficult. Also, in the case of landfill or incineration, problems such as increased treatment volume, leachate, and increased incineration costs due to moisture evaporation occur due to the approximately 89% moisture contained in sewage sludge. Therefore, in order to utilize sewage sludge, removing moisture at a low cost becomes the most important technology.

Accordingly, the use of sludge drying equipment to dry sludge to reduce its water content and then manufacture it into organic fertilizer has been increasing.

Conventional sludge drying equipment uses fossil fuels such as oil or gas to drive a burner to dry sludge. Then, the sludge moved along the drying pipe, and the burner dried the sludge by directly or indirectly applying heat to the inside of the drying pipe. At this time, the heat required for drying the sludge is 150 to 200°C, but the heat applied by the burner maintains a high temperature of 300 to 400°C inside the drying tube.

In addition, the heat and high-temperature dry gas generated during the sludge drying process are disposed of outside after undergoing dust collection treatment. Accordingly, the conventional sludge drying device had the disadvantage of wasting fuel for sludge drying. In addition, since a large amount of bad odor is generated from the drying gas generated during the drying of the sludge, there was a problem in that civil complaints due to bad odor were generated in the surrounding area.

Republic of Korea Patent No. 10-1857596 (Announcement Date: May 14, 2018) Republic of Korea Patent No. 10-2057682 (Announcement Date: January 22, 2020)

The present invention is intended to solve the problems of the prior art, and the main purpose of the present invention is to remove odorous substances contained in the generated gas and exhaust gas generated during the drying of organic waste (sludge) and recycle the waste heat to dry the sludge. A waste heat recovery type sludge drying device to reduce odor and greenhouse gases and save energy by reducing carbon dioxide by reducing the use of fossil fuels and removing odor and water vapor before discharging it to the outside to reduce environmental pollution. It's about.

The above objects and various advantages of the present invention will become more apparent to those skilled in the art from preferred embodiments of the present invention.

As a means to achieve the purpose of the present invention, the waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy according to the present invention,
A sludge drying pipe (130) that is open at both ends and through which the sludge is moved and dried;
a front cap 120 coupled to one end of the sludge drying pipe 130 in communication;
a rear cap 140 coupled to the other end of the sludge drying pipe 130 in communication;
a sludge supply unit 110 that supplies sludge to the front cap 120;
A drying pipe outer cylinder (161) provided to surround the outside of the sludge drying pipe (130);
A burner 163 provided at the lower part of the drying pipe outer cylinder 161 and supplying flame by burning fossil fuel;
a mixed combustion chamber 162 into which the generated gas C) generated from the sludge drying pipe 130 is injected;
A pyrolysis chamber (162a) connected to the mixed combustion chamber (162) and in which the odor contained in the generated gas (C) is thermally decomposed at high temperature;
A hot air supply unit 160 that is coupled to the rear end of the thermal decomposition chamber 162a and includes a catalyst 164 that removes odor contained in the generated gas C and supplies high temperature hot air to the drying pipe outer cylinder 161; ;
A heater 180 installed inside the pyrolysis chamber 162a of the hot air supply unit 160 and consisting of a plurality of heater rods that generate heat when external power is applied;
a low-temperature plasma device 171 installed to be connected to the mixed combustion chamber 162 and generating arc plasma;
A generated gas transfer pipe connects the rear cap 140 and the low-temperature plasma device 171 and moves the generated gas (C) generated when the sludge is dried inside the sludge drying pipe 130 to the low-temperature plasma device 171. (143) and;
An exhaust gas movement pipe 147 connects the drying pipe outer cylinder 161 and the generated gas moving pipe 143 and moves the exhaust gas (D) generated in the drying pipe outer cylinder (161) to be mixed with the generated gas (C). class;
a temperature sensor 137 that measures the temperature inside the sludge drying pipe 130;
It includes a control unit 200 that controls whether the burner 163 and the heater 180 are driven based on the internal temperature detected by the temperature sensor 137,
When operating the heater 180, the exhaust gas (D) moving through the exhaust gas transfer pipe 147 is mixed with the generated gas (C) moving through the generated gas transfer pipe 143 at a certain ratio to generate pollution. After diluting the material, the contaminants contained in the generated gas (C) are first removed using the arc plasma generated in the low-temperature plasma device 171, and the heater 180 installed in the pyrolysis chamber 162a The contaminants contained in the generated gas (C) undergo secondary high-temperature pyrolysis by heating while passing through, and then pass through the catalyst 164 installed at the rear end of the pyrolysis chamber 152a, whereby the contaminants are thirdly treated and then dried. By being supplied to the outer tube 161, it is possible to prevent the generation of bad odors, minimize the generation of greenhouse gases, and save energy consumption.

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According to the present invention, the use of fossil fuels is reduced by removing odorous substances contained in gases and exhaust gases generated during the drying of organic waste (sludge), recycling the waste heat to dry the sludge, and then discharging it to the outside. By reducing carbon dioxide and removing odor and water vapor before discharging it, environmental pollution can be reduced, odor and greenhouse gases can be reduced, and energy can be saved.

1 is a schematic diagram schematically showing the configuration of a waste heat recovery type sludge drying plant for reducing odor and greenhouse gases and saving energy according to the present invention;
Figure 2 is a schematic diagram schematically showing the sludge drying process of the waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy according to the present invention;
Figure 3 is a detailed view of the hot air supply unit according to the present invention shown in Figure 2;
4 is a configuration diagram showing an example of a low-temperature plasma device according to the present invention;
Figure 5 is a configuration diagram showing an example of a control unit according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when adding reference signs to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Additionally, when describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. When a component is described as being “connected,” “coupled,” or “connected” to another component, that component may be directly connected or connected to that other component, but there is another component between each component. It will be understood that elements may be “connected,” “combined,” or “connected.”

Figure 1 is a schematic diagram schematically showing the configuration of a waste heat recovery type sludge drying device 100 for reducing odor and greenhouse gases and saving energy according to the present invention, and Figure 2 is a schematic diagram showing the configuration of a waste heat recovery type sludge drying device 100 for reducing odor and greenhouse gases and saving energy. This is a schematic diagram schematically showing the sludge (A) drying process of the recovery-type sludge drying apparatus 100.
As shown, the waste heat recovery type sludge drying device 100 (hereinafter referred to as 'waste heat recovery type sludge drying device') for reducing odor and greenhouse gases and saving energy according to the present invention is open at both ends and moves the sludge. A sludge drying pipe 130 to be dried, a front cap 120 coupled in communication with one end of the sludge drying pipe 130, and a rear cap 140 coupled in communication with the other end of the sludge drying pipe 130. and a sludge supply unit 110 that supplies sludge to the front cap 120, a drying pipe outer cylinder 161 installed to surround the outside of the sludge drying pipe 130, and a lower portion of the drying pipe outer cylinder 161. It is connected to a burner 163 that supplies flame by burning fossil fuel, a mixed combustion chamber 162 into which the generated gas (C) generated from the sludge drying pipe 130 is injected, and the mixed combustion chamber 162. A pyrolysis chamber (162a) in which the odor contained in the generated gas (C) is thermally decomposed at high temperature, a catalyst 164 installed at the rear of the pyrolysis chamber (162a) to remove the odor contained in the generated gas (C), and a drying tube outside. It includes a hot air supply unit 160 including a hot air supply pipe 161a that supplies high temperature hot air to the barrel 161, and a control unit 200 that controls the overall device.
The sludge drying pipe 130 is installed to be able to rotate as a cylinder of a certain size. A front cap 120 is installed at the front end of the sludge drying pipe 130, and a rear cap 140 is installed at the rear end of the sludge drying pipe 130. At this time, the front cap 120 and the rear cap 140 support the sludge drying pipe 130 so that it can rotate. And the sludge drying pipe 130 is provided with a drying pipe rotation drive unit 150 that provides driving force to rotate the sludge drying pipe 130.

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And a sludge supply unit 110 into which sludge (A) is supplied is installed in front of the front cap 120, and a hopper 111 into which sludge (A) is supplied is installed at the top of the sludge supply unit 110. Here, sludge (A) includes various organic wastes and contains various moisture. And a dry sludge collection unit 147 is installed at the lower part of the rear cap 140 to collect the dried sludge B while passing through the sludge drying pipe 130.

Preferably, the sludge supply unit 110 is connected to a vent 112 into which the sludge (A) is input, a hopper 111 connected to the vent 112, and a lower part of the hopper 111 so that the sludge (A) falls from the hopper 111. A sludge transfer pipe 113 moves the sludge (A) to the front cap 120, and is provided across the sludge transfer pipe 113 and the front cap 120 to rotate and transfer the sludge (A) to the sludge drying pipe 130. It includes a transfer screw 115 that forcibly transfers the transfer screw 115, and a screw driver 117 that provides driving force to rotate the transfer screw 115. However, the sludge supply unit 110 is not limited to this.

The sludge drying pipe 130 is a cylindrical pipe of a certain diameter that is open at both ends, and provides an internal space through which sludge is moved and dried. One end of the sludge drying pipe 130 is provided with a sludge input hole 131 that is inserted into the front cap 120 and receives sludge (A), and the other end is inserted into the rear cap 140. A dry sludge transfer hole 133 is provided that is coupled to supply dry sludge (B) to the rear cap 140.

Preferably, the sludge drying pipe 130 is made of a metal material so that external heat can be easily transferred to the inside. The inner wall of the sludge drying pipe 130 may be provided with a plurality of protruding agitating protrusions so that the sludge can be agitated and moved.

The hot air supply unit 160 is for supplying hot air to the inside of the drying pipe outer cylinder 161, and is provided at the lower part of the drying pipe outer cylinder 161. The burner 163 generates a flame by burning fossil fuel, It supplies the heat energy required for drying the sludge (A). The hot air supply pipe (161a) is installed between the hot air supply unit (160) and the drying tube outer tube (161) and directs the hot air generated in the hot air supply unit (160) to the drying tube outer tube ( 161).

The mixed combustion chamber 162 is a space into which the flame created by the burner 163 flows and where the generated gas (C) moving from the sludge drying pipe 130 is mixed with the flame. The thermal decomposition chamber 162a is a space where the flame and generated gas C flowing from the mixed combustion chamber 162 pass through and the odor contained in the generated gas C is thermally decomposed. And the catalyst 164 is installed at the rear end of the thermal decomposition chamber 162a to remove bad odors that could not be removed by thermal decomposition. Only odor reduction hot air (G2) with reduced odor is supplied to the drying pipe outer cylinder (161) through the hot air supply pipe (161a).

The outer drying pipe 161 is made of a cylinder with a larger diameter than the sludge drying pipe 130, and forms a space of a certain size therein. The odor-reducing hot air (G2) supplied from the hot air supply unit 160 from which the odor has been removed is supplied to the inner space of the drying pipe outer cylinder 161 through the hot air supply pipe 161a.

Therefore, when raw sludge (A) containing moisture is supplied to the sludge supply unit 110, the sludge (A) is transferred to the sludge drying pipe 130 through the sludge transfer pipe 113 and the front cap 120. And while rotating the sludge drying pipe 130 by the action of the drying pipe rotation drive unit 150, hot air generated by the burner 163 of the hot air supply unit 160 is supplied to the drying pipe outer cylinder 161, and the sludge drying pipe ( 130) As the internal sludge (A) dries, the moisture contained in the sludge (A) evaporates, generating gas (C) containing a foul odor and water vapor. And in the drying pipe outer cylinder 161, the sludge drying pipe 130 is heated and the remaining exhaust gas (D) is generated.

Meanwhile, the method of drying sludge with hot air generated in the hot air supply unit 160 is divided into a direct supply method and an indirect supply method. The direct supply type supplies hot air generated in the hot air supply unit 160 to the inside of the sludge drying pipe 130 so that the hot air comes into direct contact with the sludge. The indirect supply type supplies hot air generated in the hot air supply unit 160 to the sludge drying pipe 130. (130) is supplied to the outer drying pipe surrounding the hot air to heat the sludge drying pipe and prevent direct contact with the sludge.

In the direct supply type, hot air is in direct contact with the sludge, so hot air of 200~250℃ can be used, but in the indirect supply type, heat is transferred indirectly through the drying tube outer tube, so the temperature of the hot air supplied to the drying tube outer tube is at least 300~400℃. must be maintained Therefore, the direct supply method is advantageous in terms of thermal efficiency. However, when hot air is supplied into the sludge drying pipe, the amount of generated gas (C) discharged from the sludge drying pipe increases. On the other hand, in the indirect supply type, hot air is supplied to the outer drying pipe, so the amount of generated gas (C) discharged from the sludge drying pipe is reduced, but additional exhaust gas is discharged from the outer drying pipe.

In general, generated gas (C) may contain various types of water vapor, volatile substances such as hydrogen sulfide, mercaptans (thiols), amines, and substances such as tar. Exhaust gas (D) may include combustion residues such as carbon dioxide, carbon monoxide, hydrocarbons, sulfur oxides, hydrogen sulfide, nitrogen oxides, ammonia, ozone, etc.

The temperature required for drying the sludge (A) is 150 to 200°C, and the temperature of the hot air supplied to the drying pipe outer cylinder 161 is 300 to 400°C. Therefore, the temperature of the generated gas (C) discharged from the sludge drying pipe 130 is 120 to 150°C, but the temperature of the exhaust gas (D) discharged from the outer drying pipe 161 is 250 to 300°C. In other words, compared to the generated gas (C), the exhaust gas (D) not only has less odor and is dryer, but also contains a large amount of waste heat.

If the generated gas (C) and exhaust gas (D) discharged from the sludge drying device are discharged as is, bad odor and white smoke are generated. Bad odors and white smoke are causes of complaints. In addition, large quantities of greenhouse gases are emitted, promoting weather crises such as global warming. In addition, there was a problem of low energy efficiency because the waste heat of the generated gas (C) and exhaust gas (D) was discarded as is.

Accordingly, a technology was developed by supplying the generated gas (C) discharged from the sludge drying pipe 130 to the hot air supply unit 160, pyrolyzing it with a flame, and then recycling it as a heat source for sludge drying. However, in the past, the method of thermally decomposing the generated gas (C) using a flame generated by a burner using fossil fuels had the problem of generating greenhouse gases and reducing thermal efficiency.

That is, conventionally, the burner is operated until the internal temperature of the sludge drying pipe 130 reaches 150-200°C, and when the internal temperature of the sludge drying pipe 130 rises above 150-200°C, the burner is stopped, and the sludge The generated gas (C) discharged from the drying pipe 130 is circulated to the sludge drying pipe 130 to maintain the temperature inside the sludge drying pipe 130 at 150 to 200°C. However, in the case of the indirect supply method that supplies hot air to the inside of the drying pipe outer cylinder, when generated gas (C) containing a large amount of volatile substances and tar is supplied to the drying pipe outer cylinder, the tar sticks to the inner surface of the drying pipe outer cylinder. , it can lead to problems such as volatile substances exploding in the dryer tube.

Accordingly, when the generated gas (C) is circulated through the drying tube external cylinder, the burner is operated to remove volatile substances and tar components contained in the generated gas (C) with a flame, and the temperature of the hot air is raised to 300~400℃ and supplied. is using . Therefore, the indirect supply method has the advantage of reducing odor compared to the direct supply method, but it has the disadvantage of increasing the operating time of the burner, which wastes energy and increases the generation of greenhouse gases.

In order to solve this problem, the present invention further includes a heater that uses electricity separately from the burner that uses fossil fuel, and mixes generated gas (C) and exhaust gas (D) at a certain ratio to produce generated gas (C). The concentration of contaminants such as odor and tar contained in the gas is lowered, and the temperature of the generated gas (C) is raised. It is heated by passing it through a heater, and hot air of 300-400℃ is produced and supplied to the dryer tube, thereby reducing odor. At the same time, the operating time of the burner is reduced to reduce greenhouse gas emissions and increase energy efficiency.

Specifically, the hot air supply unit 160 further includes a heater 180. The heater 180 is installed in a position where it can heat the generated gas (C) when the burner 162 is not operated. Preferably, the heater 180 may include a plurality of heater rods equipped with heating wires to which electricity is applied, and power may be supplied to the heater 180 from a power supply unit. For example, the heater 180 may be installed at the front end of the pyrolysis chamber 162a. Therefore, the generated gas (C) passing through the thermal decomposition chamber (162a) can be heated through the mixed combustion chamber (162).

And the generated gas transfer pipe 143 for supplying the generated gas (C) discharged from the sludge drying pipe 130 to the mixed combustion chamber 162 of the hot air supply unit 160, and the exhaust gas discharged from the drying pipe outer cylinder 161. An exhaust gas transfer pipe 147 is provided to supply (D) to the mixed combustion chamber 162 of the hot air supply unit 160.
In addition, it further includes a low-temperature plasma device 171 for thermally decomposing contaminants contained in the generated gas (C). That is, when generated gas C containing contaminants such as tar is supplied to the heater 180, the tar, which has strong adhesiveness, may stick to the heater rod and cause the heater to lose its function. Therefore, the low-temperature plasma device 171 prevents the heater 180 from being contaminated by thermally decomposing volatile substances or tar substances contained in the generated gas (C).

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In addition, an electrolyzer 173 that electrolyzes water so that the generated gas C can contain oxygen, hydrogen, and radical ions may be further included. The electrolyzer 173 has a plurality of electrodes installed inside and can generate hydroxyl gas by electrolyzing water. Hydroxide gas has strong oxidizing power, so it oxidizes and decomposes pollutants contained in the generated gas (C).

To this end, the electrolyzer 173 may further include a water storage tank that supplies water into the interior of the electrolyzer 173 and a power supply unit (173b) that supplies direct current power to the electrodes. In addition, a blowing fan 175 for moving the hydroxyl gas generated in the electrolyzer 173 to the low-temperature plasma device 171 may be further included.

Therefore, the odorous substances and tar contained in the generated gas (C) supplied to the heater 180 are removed by the oxidation reaction of hydroxyl gas and the thermal decomposition of arc plasma, thereby preventing the heater's performance from being deteriorated.

More specifically, the sludge supply unit 110 supplies sludge (A) to the sludge drying pipe 130. The sludge supply unit 110 is connected to a vent 112 into which the sludge (A) is input, a hopper 111 connected to the vent 112, and a lower part of the hopper 111 to collect sludge ( A sludge transfer pipe 113 moves A) to the front cap 120, and is provided across the sludge transfer pipe 113 and the front cap 120 to rotate and forcibly transfer the sludge (A) to the sludge drying pipe 130. It includes a transfer screw 115 and a screw driver 117 that provides driving force to rotate the transfer screw 115.

Sludge (A) is raw sludge containing moisture. The vent 112 discharges the air contained in the raw sludge to the outside and causes only the sludge (A) to fall into the hopper 111. The sludge transfer pipe 113 is arranged horizontally at a certain length and is coupled to the lower end of the hopper 111 to receive sludge (A). Inside the sludge transfer pipe 113, a transfer screw 115 is provided to be rotated by the screw drive unit 117. The transfer screw 115 rotates and supplies sludge (A) to the sludge drying pipe 130.

The front cap 120 is coupled to the front of the sludge drying pipe 130 to seal the sludge drying pipe 130 and supplies the sludge (A) transferred through the sludge transfer pipe 113 to the sludge drying pipe 130. In addition, the front cap 120 is coupled with the generated gas recycling pipe 167 to supply a portion of the generated gas (C) together with the sludge (A) to the sludge drying pipe (130).
The front cap 120 is provided in the form of a cylindrical tube with a larger outer diameter than the sludge drying tube 130. One end of the front cap 120 is coupled with the sludge transfer pipe 113, and the other end is coupled with the sludge drying pipe 130. Although not shown in the drawing, a sealing member is coupled to the coupling area between the front cap 120 and the sludge transfer pipe 113 and the sludge drying pipe 130 to prevent airtightness from leaking. A transfer screw 115 is disposed inside the front cap 120 to transfer the sludge (A) to the sludge drying pipe 130.

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The sludge drying pipe 130 is provided as a cylindrical pipe with both ends open, and provides a space where the sludge is moved and dried. One end of the sludge drying pipe 130 is provided with a sludge input hole 131 that is inserted into the front cap 120 and receives sludge (A), and the other end is inserted into the rear cap 140. A dry sludge transfer hole 133 is provided that is coupled to supply dry sludge (B) to the rear cap 140.

The sludge drying pipe 130 is preferably made of a metal material so that the heat applied from the hot air supply unit 160 can be transferred to the inside. The inner wall of the sludge drying pipe 130 may be provided with a plurality of protruding agitating protrusions that allow the sludge to be stirred and moved.

The drying pipe outer cylinder 161 is installed to surround the sludge drying pipe 130, and a certain air gap is formed between them. In addition, a bearing 135 is provided in the joint area between the sludge drying pipe 130 and the drying pipe outer cylinder 161, so that only the sludge drying pipe 130 rotates while the drying pipe outer cylinder 161 is fixed. Preferably, the outer peripheral surface of the drying pipe outer cylinder 161 is covered with an insulating material to prevent heat from leaking.

The drying pipe rotation drive unit 150 provides driving force to the sludge drying pipe 130 so that only the sludge drying pipe 130 rotates while the drying pipe outer cylinder 161 is fixed. Preferably, the drying pipe rotation drive unit 150 includes a driving motor 151, a driving roller 153 externally disposed on the outside of the sludge drying pipe 130, and the rotational force of the driving motor 151 is applied to the driving roller 153. ) includes a power belt (155) that transmits to.

The rotation of the drive motor 151 is transmitted to the drive roller 153 by the transmission belt 155, and the sludge drying pipe 130 is in circumscribed contact with the drive roller 153 in the rotation direction of the drive roller 153. It rotates. The drying pipe rotating drive unit 150 is provided only on one side of the sludge drying pipe 130, but may be provided on both sides if the sludge drying pipe 130 is long.

As the sludge drying pipe 130 rotates in this way, the sludge (A) moves from the sludge input hole 131 to the dry sludge transfer hole 133, and the drying process progresses by receiving heat from the hot air inside the drying pipe outer cylinder 161. .

A temperature sensor 137 is provided inside the sludge drying pipe 130. The temperature sensor 137 detects the temperature inside the sludge drying pipe 130 in real time and transmits it to the control unit 200. The control unit 200 controls whether the burner 163 and the heater 180 of the hot air supply unit 160 are driven based on the internal temperature detected by the temperature sensor 137.

Meanwhile, the method of supplying hot air generated in the hot air supply unit 160 to dry sludge is divided into a direct supply method and an indirect supply method. The direct supply type is a method of supplying hot air generated from the hot air supply unit 160 directly into the inside of the sludge drying pipe 130 to dry the hot air by contacting the sludge, and the indirect supply type is a method of drying the sludge using hot air generated from the hot air supply unit 160. This is a method in which hot air is supplied to the drying pipe outer cylinder 161 surrounding the pipe 130, heats the sludge drying pipe 130, and conducts the sludge to the heated sludge drying pipe 130.

The direct supply type has excellent thermal efficiency by using hot air of 200 to 250°C because the hot air is in direct contact with the sludge. However, if the hot air generated in the burner 163 of the hot air supply unit 160 is supplied directly to the inside of the sludge drying pipe 130, There is a disadvantage in that the amount of generated gas (C) increases as the sludge (A) inside the sludge drying pipe 130 is dried, and the generated gas (C) contains a large amount of water vapor and odorous substances. On the other hand, the indirect supply method transfers heat to the sludge indirectly by heating the drying pipe outer cylinder, so the temperature of the hot air must be high at 300-400°C, so it has the disadvantage of low thermal efficiency, but the hot air generated in the burner 163 of the hot air supply unit 160 Since it is not directly supplied into the sludge drying pipe 130, the amount of generated gas (C) is reduced. And in the drying pipe outer cylinder to which hot air is supplied, the exhaust gas (D) remaining after heating the sludge drying pipe (131) (131) is generated.

In general, generated gas (C) may contain volatile substances such as hydrogen sulfide, mercaptans (thiols), amines, and substances such as tar along with water vapor. Exhaust gas (D) may include combustion residues such as carbon dioxide, carbon monoxide, hydrocarbons, sulfur oxides, hydrogen sulfide, nitrogen oxides, ammonia, ozone, etc. And compared to the generated gas (C), the exhaust gas (D) has a lower content of pollutants and a higher temperature.

And fossil fuels and electricity can be used as heat sources to generate hot air for drying sludge. Conventionally, flames generated by burners using fossil fuels were mainly used. Flame has the advantage of superior thermal efficiency compared to electricity. However, as weather crises such as global warming have recently emerged, ways to use electricity that does not emit greenhouse gases are being studied.

On the other hand, if the generated gas (C) discharged from the sludge drying pipe and the exhaust gas (D) discharged from the drying pipe outer cylinder are discharged as is, bad odor and white smoke are generated, which becomes the cause of civil complaints. Accordingly, a technology was developed in which the generated gas (C) discharged from the sludge drying pipe 130 is supplied to the hot air supply unit 160, pyrolyzed by flame, and then recycled as a heat source for sludge drying. However, when installing a plurality of heater rods inside the hot air supply unit 160 to use electricity, the tar component contained in the generated gas (C) attaches and reduces the thermal efficiency of the heater rods, thereby substantially using electricity to remove sludge. There were many problems with drying.

For example, conventionally, a plurality of heater rods are additionally installed inside the hot air supply unit 160, and the burner is operated until the internal temperature of the sludge drying pipe 130 reaches 150 to 200° C. to dry the sludge with a flame. , When the internal temperature of the sludge drying pipe (130) rises above 150-200°C, the operation of the burner is stopped, and power is supplied to the heater rod to heat the generated gas (C) circulating in the sludge drying pipe (130) to dry the sludge. The temperature inside the tube 130 is maintained at 150 to 200°C.

However, there was a problem in which the tar component contained in the generated gas (C) supplied to the hot air supply unit 160 stuck to the heater rod. Tar is generated when organic substances or biomass raw materials are heated and the molecular structure decomposes. Primary tar is a substance produced when cellulose, hemicellulose, and lignin, the main components of biomass, are decomposed, and substances produced as secondary tar are phenolics and olefins. Tertiary tar generates PAH and condensable aromatic compounds, and tertiary tar mostly contains substances with high molecular weight. The above-mentioned secondary tar and tertiary tar originate from primary tar.

Accordingly, the waste heat recovery type sludge drying device 100 according to the present invention further includes a low-temperature plasma device 171 that thermally decomposes the tar component contained in the generated gas (C) supplied to the hot air supply unit 160.

In other words, the gas generated during thermal decomposition and gasification contains tar composed of heavy hydrocarbons. Tar is a factor that causes various problems that must be solved in subsequent processes using generated gas. As a representative example, tar components condense on the inner wall of the hot air supply unit 160 or the outer surface of the heater rod, blocking heat exchange.

Arc plasma can not only effectively reduce tar generated in the sludge pyrolysis/gasification process, but can also be converted into synthesis gas containing H2, CO, and CO2 through an additional reaction with water vapor. The advantages of arc plasma include easy control of the reactor, high conversion rate, high energy efficiency, and environmental friendliness.

Plasma is a state in which when heat is applied to a substance in a gaseous state or electric energy is applied to the gas, violent collisions occur between the gas molecules, and positive ions and electrons are generated inside the gas, and the generated positive ions and electrons move and wander around. This state is defined as the fourth state of matter. Because the overall negative and positive charges are the same, it is electrically neutral, and because it possesses high energy, the degree of charge separation is quite high, generating various active chemical species (electrons, ions, atoms, radicals, various excited molecules) and Because energy can be easily transferred to materials, it has the ability to convert and reform materials that are difficult to decompose chemically and stably when injected into a plasma state.

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This plasma state can be divided into high-temperature plasma and low-temperature plasma considering the temperature of the plasma. In high-temperature plasma, a discharge is formed when the injected power is more than 1KW, and the generated neutrons and electrons are heated to the same temperature of 5000~10000K. maintain. Considering the power consumption, there is a problem with economic feasibility because the energy consumption is very large. Low-temperature plasma has high energy efficiency and induces good chemical reactions, making it suitable for treating low-concentration harmful gases.

As shown in Figures 3 and 4, the low-temperature plasma device 171 largely consists of electrodes 171a and 171b, a power supply device 172 that supplies power to the electrodes, and a generated gas transfer pipe ( 134), and a water vapor supply pipe 174 that supplies water vapor or hydroxyl gas to the inside of the generated gas transfer pipe 134.

In the low-temperature plasma device 171, three blade-shaped electrodes 171a, 171b, and 171c are installed at intervals of 120 degrees based on the center of the inside. The spacing between electrodes was maintained at 3mm and insulated with ceramic. A spray nozzle with a diameter of 1.5 to 2 mm is provided at the tip of the generated gas supply pipe 143. The power supply device 172 is a high voltage power supply with a maximum capacity of 15 kW and applies high voltage to the electrode. The water vapor supply pipe 174 is connected to a water pump, a water tank, and a heater, and the water pump supplies water from the water tank to the heater. The heater heats the water to generate water vapor and supplies it to the water vapor supply pipe 174.

As shown in Figure 4, the arc plasma discharge area can be divided into an initial discharge area (A), an equilibrium stage (B), and a non-equilibrium stage (C). When power is supplied, arc plasma is generated at the shortest point of the electrode. The generated plasma discharge spark follows the flow of gas flowing in from the lower part of the electrode, picks up the electrode, and moves to the upper part of the electrode (area B). The plasma discharge spark that moves to the upper part of the electrode disappears at the end of the electrode (area B). Area C) As soon as the discharge spark disappears, the arc regenerates at the bottom where the electrode spacing is closest, and this phenomenon is repeated, maintaining the art plasma discharge.

Meanwhile, the waste heat recovery type sludge drying apparatus 100 according to the present invention is equipped with a heater 180 using electricity along with a burner using fossil fuel inside the hot air supply unit 160. The heater 180 may be installed on a path through which the generated gas (C) passes, and includes a heater rod that generates heat when electricity is applied. Additionally, a power supply device that applies power to the heater rod is provided. For example, the heater 180 may be installed at the tip of the thermal decomposition chamber 162a of the hot air supply unit 16. Therefore, the generated gas (C) passing through the thermal decomposition chamber (162a) can be heated.

In addition, the waste heat recovery type sludge drying device 100 according to the present invention includes a generated gas transfer pipe (C) for transferring the generated gas (C) generated in the sludge drying pipe 130 to the mixed combustion chamber 162 of the hot air supply unit 160 143) is provided. The generated gas transfer pipe 143 is installed to connect the rear cap 140 and the low-temperature plasma device 171. And the generated gas (C) that has passed through the low-temperature plasma device 171 is connected to be introduced into the mixed combustion chamber 162 of the hot air supply unit 160. A first valve 143a and an exhaust fan 145 that are opened and closed under the control of the control unit 200 are installed in the generated gas transfer pipe 143.
In addition, the waste heat recovery type sludge drying device 100 according to the present invention includes an exhaust gas transfer pipe 147 that moves the exhaust gas D discharged from the drying pipe outer cylinder 161 to the mixed combustion chamber 162 of the hot air supply unit 160. ) is installed. The exhaust gas movement pipe 147 may be installed to connect the top of the drying pipe outer cylinder 161 and the low-temperature plasma device 171, or may be installed to connect to the middle of the generated gas movement pipe 143. For example, it may be connected to the rear of the exhaust fan 145. In addition, the exhaust gas transfer pipe 147 is provided with a second valve 147a that is opened and closed under the control of the control unit 200, and the exhaust gas transfer pipe 147 is provided to prevent the generated gas C from flowing back toward the exhaust gas transfer pipe 147. A check valve (147b) is installed.

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Therefore, the generated gas (C) moving through the generated gas movement pipe 143 and the exhaust gas (D) moving through the exhaust gas moving pipe 147 are injected between the electrodes of the low-temperature plasma device 171 or are combined with the generated gas (C). After mixing the exhaust gas D, it can be sprayed between the electrodes of the low-temperature plasma device 171.

For example, after the exhaust gas (D) and the generated gas (C) are mixed at a certain ratio, they pass through the low-temperature plasma device 171, and the generated gas (C) discharged from the low-temperature plasma device 171 is sent to the hot air supply unit ( It is supplied to the mixed combustion chamber 162 of 160). In this way, by mixing the generated gas (C), which contains a large amount of water vapor and pollutants, with the high-temperature dry exhaust gas (D), the concentration of pollutants contained in the generated gas (C) can be lowered and the temperature can be adjusted to an appropriate range. . And the generated gas (C) sprayed into the low-temperature plasma device 171 along the generated gas transfer pipe 143 is in contact with the arc plasma, and the tar component consisting of carbon (C), hydrogen (H), and oxygen (O) is formed. Molecular links are broken and thermal decomposition occurs. That is, the generated gas (C) moving along the generated gas transfer pipe 143 passes through the low-temperature plasma device 171 and then is injected into the mixed combustion chamber 162 of the hot air supply unit 160. And, it can be heated to an appropriate temperature while passing through the heater 180 installed in the thermal decomposition chamber 162a.

In this way, the present invention mixes the generated gas (C) and the exhaust gas (D) at a certain ratio, lowers the concentration of pollutants contained in the generated gas (C), and increases the temperature of the generated gas (C) to a static range. After removing contaminants by spraying them into the low-temperature plasma device 171, they are heated by passing through the heater 180, and hot air of 300 to 400°C is generated and supplied to the drying pipe outer cylinder 161, thereby reducing odor and at the same time reducing the burner's temperature. By reducing operating time, greenhouse gases can be reduced and energy efficiency can be improved.

In addition, the hydroxide gas and water vapor generated in the electrolyzer 173 and containing oxygen, hydrogen, and radical ions are mixed with the generated gas (C) and sprayed into the low-temperature plasma device 171 to improve the thermal decomposition ability of pollutants. You can.

For this purpose, as shown in FIG. 3, a power supply device that supplies direct current power to the water storage tank and electrodes that supply water into the electrolyzer 173, and a low-temperature plasma device 171 that supplies hydroxyl gas generated in the electrolyzer 173. It may further include a blowing fan moving to. Additionally, a pump may be further provided to pump water in the water storage tank to the electrolyzer 173.

As shown in FIG. 5, the control unit 200 is electrically connected to and controls multiple power supplies, multiple driving motors, and multiple valves. The control unit 200 regulates the opening and closing of the first valve 143a, the second valve 165a, and the third valve 167a. Additionally, the control unit 200 controls whether the burner 163 and the heater 180 are driven based on the internal temperature of the sludge drying pipe 130 transmitted from the temperature sensor 137.

For example, when the temperature sensor 137 transmits the internal temperature of the sludge drying pipe 130 to the control unit 200, the control unit 200 turns on the burner if the internal temperature is lower than the set reference temperature (e.g., 150°C). Power is supplied to (163), and if the temperature is higher than the standard temperature, power is cut off to the burner (163) and power is supplied to the heater (180).

When the burner 163 generates a flame, the control unit 200 cuts off the power supply to the low-temperature plasma device 171, supplies the generated gas and exhaust gas to the mixed combustion chamber 162 of the hot air supply unit 160, and flames. and the tar component and odorous substances contained in the generated gas (C) are thermally decomposed and removed in the thermal decomposition chamber (162a). And contaminants that cannot be removed by thermal decomposition are oxidized and decomposed through the catalyst 164 installed at the rear end of the thermal decomposition chamber 162a.

Conversely, when the heater 180 is operated, the control unit 200 supplies power to the low-temperature plasma device 171, supplies generated gas and exhaust gas to the low-temperature plasma device 171, and supplies the generated gas (C) to the generated gas (C). The included tar components and odorous substances are thermally decomposed and then supplied to the mixed combustion chamber 162 of the hot air supply unit 160. Then, the generated gas (C) from which the tar component has been removed is heated as it passes through the heater 180 and is thermally decomposed secondarily. And contaminants that cannot be removed by thermal decomposition are oxidized and decomposed through the catalyst 164 installed at the rear end of the thermal decomposition chamber 162a.

When spraying water vapor into the low-temperature plasma device 171, the water increasing supply unit is operated, and when spraying hydroxyl gas into the low-temperature plasma device 171, the hydroxide gas supply unit is operated. And the hot air from which the bad odor has been removed passes through the catalyst 164 and is supplied to the inside of the drying cabinet 161 through the hot air supply pipe 161a. The temperature of the hot air supplied to the drying pipe outer cylinder 161 through the hot air supply pipe 161a is around 300 to 400°C. Hot air is supplied to the drying pipe outer cylinder 161 and then applied heat to the sludge drying pipe 130 to dry the sludge (A) in the sludge drying pipe 130.

And, part of the exhaust gas (D) generated from the drying pipe outer cylinder 161 is circulated and recycled through the exhaust gas transfer pipe 147, and the remainder is discharged to the outside through the exhaust gas discharge pipe. Likewise, part of the generated gas (C) generated in the sludge drying pipe 130 is recycled by circulating through the generated gas transfer pipe 134, and the remainder is discharged to the outside.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. It is considered to be within the scope of the claims of the present invention to the extent that anyone skilled in the art can make modifications without departing from the gist of the invention as claimed in the claims.

110: Sludge supply unit 120: Front cap
130: Sludge drying pipe 140: Rear cap
143: Generated gas transfer pipe 147: Exhaust gas transfer pipe
160: Hot air supply unit 161: Drying pipe outer cylinder
162: Mixed combustion chamber 162a: Pyrolysis chamber
163: burner 164: catalyst
200; Control unit 171: low temperature plasma device
173: electrolyzer 180: heater
200: control unit

Claims (4)

A sludge drying pipe (130) that is open at both ends and through which the sludge is moved and dried;
a front cap 120 coupled to one end of the sludge drying pipe 130 in communication;
a rear cap 140 coupled to the other end of the sludge drying pipe 130 in communication;
a sludge supply unit 110 that supplies sludge to the front cap 120;
a drying pipe outer cylinder (161) provided to surround the outside of the sludge drying pipe (130);
A burner 163 provided at the lower part of the drying pipe outer cylinder 161 and supplying flame by burning fossil fuel;
a mixed combustion chamber 162 into which the generated gas (C) generated from the sludge drying pipe 130 is injected;
A pyrolysis chamber (162a) connected to the mixed combustion chamber (162) and in which the odor contained in the generated gas (C) is thermally decomposed at high temperature;
A hot air supply unit 160 that is coupled to the rear end of the thermal decomposition chamber 162a and includes a catalyst 164 that removes odor contained in the generated gas C and supplies high temperature hot air to the drying pipe outer cylinder 161; ;
A heater 180 installed inside the pyrolysis chamber 162a of the hot air supply unit 160 and consisting of a plurality of heater rods that generate heat when external power is applied;
a low-temperature plasma device 171 installed to be connected to the mixed combustion chamber 162 and generating arc plasma;
A generated gas transfer pipe connects the rear cap 140 and the low-temperature plasma device 171 and moves the generated gas (C) generated when the sludge is dried inside the sludge drying pipe 130 to the low-temperature plasma device 171. (143) and;
An exhaust gas movement pipe 147 connects the drying pipe outer cylinder 161 and the generated gas moving pipe 143 and moves the exhaust gas (D) generated in the drying pipe outer cylinder (161) to be mixed with the generated gas (C). class;
a temperature sensor 137 that measures the temperature inside the sludge drying pipe 130;
It includes a control unit 200 that controls whether the burner 163 and the heater 180 are driven based on the internal temperature detected by the temperature sensor 137,
When operating the heater 180, the exhaust gas (D) moving through the exhaust gas transfer pipe 147 is mixed with the generated gas (C) moving through the generated gas transfer pipe 143 at a certain ratio to generate pollution. After diluting the material, the contaminants contained in the generated gas (C) are first removed using the arc plasma generated in the low-temperature plasma device 171, and the heater 180 installed in the pyrolysis chamber 162a The contaminants contained in the generated gas (C) undergo secondary high-temperature pyrolysis by heating while passing through, and then pass through the catalyst 164 installed at the rear end of the pyrolysis chamber 162a, whereby the contaminants are treated thirdly and then dried. A waste heat recovery type sludge drying device for reducing odor and greenhouse gases and saving energy that prevents the generation of odor, minimizes the generation of greenhouse gases, and saves energy consumption by being supplied to the external tube (161). delete delete delete