JP6591874B2 - Hydrous sludge drying system - Google Patents

Description

  The present invention relates to a water-containing sludge drying system for drying water-containing sludge such as sewage sludge into fuel.

  In recent years, incineration disposal has been widely adopted as a method for treating sewage sludge such as sewage sludge discharged from a sewage treatment plant due to restrictions on prevention of environmental pollution and problems of depletion of disposal sites. And as an example of the said incineration disposal, performing the said incineration disposal in the dry kiln for cement clinker manufacture is implemented.

  As a method of treating hydrous sludge using such a facility for producing cement clinker, in Patent Document 1 below, oil is mixed in organic sludge and heated while maintaining fluidity to remove moisture in the sludge. An organic sludge treatment method has been proposed in which the dried sludge obtained by evaporation is thrown into the cement clinker firing step.

  However, when the method of drying the sewage sludge prior to incineration is used, particularly during the process of heating the sewage sludge to evaporate the moisture and the process of transporting the dried sludge, bad odor due to ammonia contained in the sewage sludge is present. It may occur and the surrounding environment may be deteriorated.

  Therefore, in the following Patent Document 2, a cement clinker having a preheater for preheating the cement raw material crushed by the raw material mill, and a dry kiln in which the preheater is connected to the kiln bottom part and firing the preheated cement raw material. Is a sewage sludge treatment facility that is attached to the production facility of this type, and includes a sludge tank that stores sewage sludge in a water-containing slurry, a pump that pumps sewage sludge in the sludge tank, and a pump connected to the pump. There has been proposed a water-containing sludge treatment facility characterized by comprising a pipe for directly feeding sewage sludge into a dry kiln and connecting the pipe to a kiln bottom or a calciner.

  According to the treatment of sewage sludge using the water-containing sludge treatment facility, the sewage sludge is directly incinerated with an existing dry kiln without any pretreatment such as drying or addition of additives, or environmental pollution problems. By doing so, the final disposal can be performed efficiently and at low cost, and since the sewage sludge is pumped and directly incinerated, there is an effect that problems such as odor do not occur.

Japanese Patent Laid-Open No. 58-92718 Japanese Patent No. 3246509

  However, in the above processing facility in which the sewage sludge is directly fed into the dry kiln, a part of the fuel for firing the cement raw material is consumed for evaporation of the water of the sewage sludge in the dry kiln. Therefore, it is necessary to increase the supply amount of the fuel. As a result, there is a problem that the amount of heat discarded as exhaust gas from the cement manufacturing facility increases and the overall thermal efficiency decreases.

  The present invention has been made in view of the above circumstances, and it is possible to efficiently dry and incinerate water-containing sludge without reducing thermal efficiency in incineration equipment and without causing problems such as odor. It is an object of the present invention to provide a water-containing sludge drying system.

  In order to solve the above-mentioned problem, the water-containing sludge drying system according to claim 1 includes a first drying device including a heating member that heats the water-containing sludge by indirect heating with a first heat medium to evaporate water. The primary dewatered sludge discharged from the first drying device is pressurized to remove a part of the contained water, and the secondary dewatered sludge discharged from the uniaxial press is used as the first heat. A second drying device provided with a heating member that is heated by indirect heating with a medium to evaporate moisture to form dry sludge; and the first heating medium in the heating member of the first and second drying devices. A first circulation line that circulates and supplies the first heating medium, and a reheating device that is interposed in the first circulation line and reheats the first heat medium discharged from the first and second drying devices. It is characterized by comprising .

  The invention according to claim 2 is the invention according to claim 1, wherein a mixer for adding a dehydrating aid to the primary dewatered sludge and mixing is disposed at the front stage of the uniaxial press. It is characterized by.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the reheating device includes a second circulation line that circulates the second heat medium, and the second circulation line. And a first heat exchanger that heats the first heat medium to a supply temperature to the drying device, and an expansion valve that adiabatically expands the second heat medium discharged from the first heat exchanger. A second heat exchanger that heats the second heat medium that has passed through the expansion valve with steam discharged from the first and / or second drying device, and a second heat exchanger that discharges the second heat medium from the second heat exchanger. The second heating medium is provided with auxiliary heating means for heating to the supply temperature to the first heat exchanger.

  According to a fourth aspect of the present invention, in the invention according to the third aspect, the auxiliary heating means is an electric motor that adiabatically compresses the second heat medium discharged from the second heat exchanger to raise the temperature. It is characterized by being a compressor.

  The invention according to claim 5 is the invention according to claim 3 or 4, characterized in that the first heat medium is steam and the second heat medium is flon. .

  According to the invention according to any one of claims 1 to 5, the hydrated sludge can be dried by the drying system, and the obtained dried sludge can be incinerated in the incineration facility. Compared with the case of directly injecting into the incineration facility, the amount of heat discharged from the incineration facility and discarded can be reduced as much as possible, and thus the overall thermal efficiency can be improved.

  At this time, according to a verification experiment by the present inventors, when the water-containing sludge containing about 80% by weight of water such as sewage sludge is dried, the water is evaporated and the amount of water is 40% by weight. It was found that the fluidity of the water-containing sludge was the lowest when it was reduced to around% and hindered smooth movement in the drying apparatus.

  Therefore, in the present invention, the primary dewatered sludge whose water content has been reduced by the evaporation of water in the first drying device is once extracted from the first drying device, and a part of the water is removed by a uniaxial press. After the secondary dewatered sludge having improved fluidity is obtained, this is further supplied to the second drying device to obtain the dried sludge. For this reason, in the said 1st drying apparatus, after adjusting and extracting so that the moisture content of the said primary dewatered sludge may be about 40 weight%, after removing water further with a uniaxial pressing machine, it was set as the secondary dehydrated sludge. Then, by supplying again to the second drying device and drying, it becomes possible to make the hydrated sludge smoothly into dry sludge.

  Moreover, when it is applied to sewage sludge as hydrated sludge, the chlorine content (NaCl) contained in the sewage sludge can be removed together with moisture when part of the contained moisture is removed by the uniaxial press. Therefore, even when the dried sludge as the final product is put into the dry kiln and used as a part of the fuel, harmful effects such as blocking of the preheater occur due to the chlorine content brought into the dry kiln. Can be deterred.

  In addition, conventionally, when water-containing sludge such as sewage sludge is dried, it is directly dried by a combustion flame or the like. As a result, combustion gas is added to the vapor evaporated from the water-containing sludge and the amount of exhaust gas is increased. For this reason, when the exhaust gas is drained by a condenser and subjected to purification treatment and then drained into a river, the heat contained in the exhaust gas has been wasted.

  On the other hand, in the present invention, in the first and second drying apparatuses, the moisture in the hydrated sludge and the secondary dewatered sludge is evaporated by indirect heating. The exhaust gas extracted from the apparatus is only the vapor evaporated from the hydrous sludge and the secondary dewatered sludge. In addition, as described above, the second drying apparatus is supplied with the secondary dewatered sludge from which part of the contained moisture has been further removed from the primary dewatered sludge in the uniaxial press.

  For this reason, when the exhaust gas is drained and purified, the amount of drain generated can be reduced, thus facilitating the purification process, and particularly when the hydrated sludge is sewage sludge. In addition to facilitating countermeasures against the odor of the exhaust gas, it is possible to separate the ammonia component from the exhaust gas and use it separately.

  Incidentally, sewage sludge is generally transported after being dehydrated in advance at a sewage treatment plant by a dehydration device such as a high-pressure filter press or screw press. However, depending on the dehydration device, the water content is reduced to 80% or less. It was difficult to reduce. This is presumed to be because activated sludge such as sewage sludge has a gel-like surface when pressurized and dehydrated, and as a result, further water drainage is sealed.

  In contrast, in the present invention, the primary dewatered sludge once extracted from the first drying device is uniaxially pressed with a much higher surface pressure than other dewatering devices such as the filter press and screw press. Therefore, the moisture contained in the primary dewatered sludge can be further removed.

  In addition, as in the invention described in claim 2, if a mixer for adding a dehydrating aid to primary dewatered sludge and mixing is disposed in the previous stage of the uniaxial press, in the mixer, the primary By thoroughly mixing the dewatered sludge and the dewatering aid, the gel shape on the surface of the primary dewatered sludge is broken to form a water drainage path inside, thereby enhancing the dewatering effect by the uniaxial press. . For example, air can be used as the dehydration aid.

  Furthermore, in the invention described in claim 3, the moisture contained in the water-containing sludge or the secondary dewatered sludge by indirect heating using the first heat medium circulated in the first and second drying apparatuses. In the second heat exchanger of the reheating device, and the exhaust gas (steam) discharged from the first and / or second drying device also reheats the first heat medium. Therefore, the thermal efficiency in drying the hydrous sludge can be further increased.

  Note that the first heating medium discharged by exchanging heat with sewage sludge or secondary dewatered sludge in the first and second drying devices is required in the first and second drying devices in the reheating device. In order to raise the temperature to the required temperature, the amount of heat is insufficient with only the vapor evaporated from the sewage sludge or the secondary dewatered sludge, and therefore an auxiliary heating means for compensating for the shortage is necessary.

  As the auxiliary heating means, it is possible to use a part of the exhaust gas discharged from the auxiliary boiler or the incineration facility. For example, as in the invention according to claim 4, it is discharged from the second heat exchanger. By using an electric compressor that adiabatically compresses and heats up the second heat medium that has been used, the entire facility becomes compact and the thermal efficiency can be further improved without requiring a large facility for the auxiliary boiler. . In addition, it is possible to easily control the temperature of the first heat medium by controlling the rotation speed of the electric motor.

It is a schematic structure figure showing one embodiment of the present invention. It is a schematic block diagram which shows the auxiliary | assistant heating means of FIG.

1 and 2 show an embodiment of a water-containing sludge drying system according to the present invention. Reference numeral 4 in the figure denotes sewage sludge which has been transported by a transport vehicle such as a dump truck and has a water content of about 80% by weight. A hopper into which (hydrous sludge) is charged.
A transport unit 21 that transports sewage sludge discharged from the hopper 4 is provided below the hopper 4, and the drying device 1 is disposed upstream of the transport unit 21.

  In this drying apparatus 1, a heating member 2 is rotatably provided by an electric motor (not shown) in a cylindrical main body 1 a whose both end faces are closed. The heating member 2 has a plurality of disk-type stirring blades (hereinafter abbreviated as disks) 2b fixed to the main shaft 2a at equal intervals in the axial direction. In addition, a stirring blade is attached for the purpose of scooping and transferring the processed material (sewage sludge in the present embodiment).

  The heating member 2 is formed so that both the main shaft 2a and the disk 2b are hollow, and steam is connected to both ends of the main shaft 2a extending outward from the main body 1a of the drying apparatus 1 via rotary joints. The supply side 3a and the discharge side 3b in the circulation line (first circulation line) 3 of the (first heat medium) are connected.

  In addition, a raw material charging port 5a for supplying sewage sludge from the discharge part of the uniaxial press 22 to the inside of the drying apparatus 1 is provided at the upper part of the main body 1a to which the steam discharge side 3b is connected. ing. Further, the interior of the dryer 1 is divided into a first drying chamber (first drying device) 23 and a second drying chamber (second drying device) 24 by a partition wall 22.

  A chute 6 a for discharging the primary dewatered sludge dried in the first drying chamber 23 is provided on the most downstream side surface of the first drying chamber 23. A chute 6b for discharging the dried sludge dried in the second drying chamber 24 is provided on the downstream side. These chutes 6a and 6b are for discharging the primary dewatered sludge or dried sludge sent to the downstream side by the disk 2b to the outside by the side overflow method.

  A transport means 25 for transporting the primary dewatered sludge to the mixer 26 is provided at the discharge port of the chute 6 a of the first drying chamber 23. This mixer 26 mixes and stirs and mixes air (drying aid) with primary dewatered sludge, and a uniaxial press 27 is provided on the downstream side of the mixer 26.

  The uniaxial pressing machine 27 is generally composed of a solid wire net on which the primary dewatered sludge is placed and an electric or hydraulically driven cylinder that presses the primary dewatered sludge on the wire net. Then, the secondary dewatered sludge discharged from the uniaxial compressor 27 is introduced into the second drying chamber 24 from the charging port 5b provided adjacent to the partition wall 22 of the drying device 1. .

  Further, an exhaust pipe 7a for discharging steam generated from sewage sludge by being heated by the heating member 2 in the first drying chamber 23 is provided at the upper end portion of the main body 1a of the drying apparatus 1; An exhaust pipe 7b for discharging steam generated from the secondary dewatered sludge by being heated in the drying chamber 24 is connected.

  The exhaust pipes 7a and 7b are provided with a dust collector 8 for collecting dust accompanying the steam. As this dust collector 8, a bag filter or a sinter lamellar filter (registered trademark of Nippon Steel Mining Co., Ltd.) is suitable. The dust collector 8 is provided with a return pipe 9 for returning the collected dust to the drying device 1 again.

The steam circulation line 3 is provided with a reheating device 10 for reheating steam including drain discharged from the main body 1a.
As shown in FIG. 2, the reheating device 10 includes a circulation line (second circulation line) 11 that circulates chlorofluorocarbon (second heat medium), and the circulation line 11. A condenser (first heat exchanger) 12 that heats the steam to the supply temperature to the drying device 1, an expansion valve 13 that adiabatically expands the chlorofluorocarbon discharged from the condenser 12, and chlorofluorocarbons that have passed through the expansion valve 13 The evaporator (second heat exchanger) 14 is heated by steam supplied from the dust collector 8 through the collective exhaust pipe 7, and the flon discharged from the evaporator 14 is adiabatically compressed to condense the condenser 12. And a compressor (auxiliary heating means) 15 for heating up to the supply temperature. Reference numeral 16 in the figure denotes an electric motor for driving the compressor 15 to rotate.

  Moreover, the vapor | steam which heated the fluorocarbon in the evaporator 14 becomes a drain, and is introduce | transduced into the drain tank 17 from the discharge pipe 7c. In the drain tank 17, the air containing the accompanying ammonia is separated and taken out from the upper exhaust pipe 18.

  On the other hand, the drain from which the gas component is separated in the drain tank 17 is supplied as industrial water after passing through the separation membrane 20 from the drain pipe 19 as shown in FIGS. . The separation membrane 20 is preferably a nanofiltration membrane or a reverse osmosis membrane that can prevent mixing of sodium chloride.

  In order to dry the sewage sludge by the water-containing sludge drying system having the above-described configuration, about 80% by weight of the sewage sludge having been put into the hopper 4 by a transport vehicle such as a dump truck is extracted and dried by the transport means 21. The material is supplied into the first drying chamber 23 from the raw material inlet 5 a of the apparatus 1.

  Then, in the first drying chamber 23, the sewage sludge is sequentially sent toward the partition wall 22 side with the rotation of the disk 2b, and indirectly heated by the heating member 2 in the process, and is included in the sewage sludge. Moisture is evaporated. Then, it is dried to a predetermined moisture (about 40% by weight) that eventually deteriorates in fluidity, becomes primary dewatered sludge, overflows the gate provided on the chute 6a, and is discharged downward from the chute 6a. go.

  Next, the primary dewatered sludge discharged from the chute 6a is sent from the conveying means 25 to the mixer 26, and is stirred and mixed with air (drying aid) and then supplied to the uniaxial press 27. And in this uniaxial pressing machine 27, the primary dewatered sludge on the wire mesh mixed with air is pressed and compressed by a cylinder.

  Then, the uniaxial pressing machine 27 has a much higher surface pressure than other dewatering devices such as a filter press and a screw press, and the primary dewatered sludge is mixed with air, thereby flowing down the internal moisture. Since a flow path for forming the water is formed, a part of the water contained in the primary dewatered sludge is further dropped and removed from the wire mesh, so that the water content is less than 40% by weight. Becomes a secondary dewatered sludge.

  Then, next, the secondary dewatered sludge discharged from the primary press 27 is supplied into the second drying chamber 24 in the drying device 1 from the charging port 5b, and at the same time, the reheating device 10 performs about Steam heated to 165 ° C. is supplied into the heating member 2 from the supply side 3 a of the circulation line 3. As a result, the secondary dewatered sludge is sequentially sent to the downstream side along with the rotation of the disk 2b, and indirectly heated by the heating member 2 in the process, so that the water contained in the secondary dewatered sludge evaporates. To do. Then, it is finally dried to a predetermined moisture (about 10% by weight), becomes dry sludge, overflows the gate provided on the chute 6b, and is discharged downward.

  A part of the dried sludge discharged from the chute 6b in this way is put into a dry kiln of a cement manufacturing facility and used as a part of fuel. Further, the vapors evaporated from the sewage sludge or the secondary dewatered sludge in the first drying chamber 23 and the second drying chamber 24 of the drying device 1 are sent to the dust collector 8 from the exhaust pipes 7a and 7b, respectively, and are separated from the dust. Is collected as a heat source from the collecting exhaust pipe 7 to the evaporator 14 of the reheating device 10.

  On the other hand, the steam in the heating member 2 cooled by heating the sewage sludge in the first drying chamber 23 becomes steam of about 120 ° C. containing drain and is sent out from the discharge side 3b to the circulation line 3 to be reused. It is introduced into the condenser 12 of the heating device 10. In this condenser 12, the temperature is raised again to the supply temperature (about 165 ° C.) to the heating member 2 by the chlorofluorocarbon in the circulation line 11, and then from the supply side 3 a of the circulation line 3 to the heating member 2 of the drying device 1. Go supplied.

  On the other hand, the chlorofluorocarbon, which has been cooled by heating the steam in the condenser 12, is adiabatically expanded in the expansion valve 13 interposed in the circulation line 11, and is further cooled to be sent to the evaporator 14. It exchanges heat with the steam supplied from the pipe 7 and is heated to evaporate. The evaporated chlorofluorocarbon is heated to a temperature to be supplied to the condenser 12 by adiabatic compression by the compressor 15. In this way, the chlorofluorocarbon is circulated through the circulation line 11 in the reheating device 10.

  Moreover, the vapor | steam which heated the chlorofluorocarbon in the evaporator 14 falls, becomes a drain, and is introduce | transduced into the drain tank 17 from the discharge pipe 7c. In the drain tank 17, the air containing the accompanying ammonia is separated and taken out from the upper exhaust pipe 18. The drain from which the ammonia content has been removed in this way is passed through the separation membrane 20 from the drain pipe 19 of the drain tank 17, and after the residue is removed, it is supplied separately as industrial water.

  As described above, according to the water-containing sludge drying system having the above-described configuration, the sewage sludge is dried by the drying system, and the obtained dried sludge is put into a dry kiln of a cement manufacturing facility, so that a part of the fuel is obtained. Because it can be incinerated after being used as a wastewater, the amount of heat discharged from the incinerator is discarded as much as possible compared to the case where it is directly put into the incinerator without drying. Thus, the overall thermal efficiency can be improved.

  In addition, in the first and second drying chambers 23 and 24, the water contained in the water-containing sludge and the secondary dewatered sludge is evaporated by indirect heating using the steam circulated from the circulation line 3, and reheating is performed. In the evaporator 14 of the apparatus 10, the steam discharged from the first and second drying chambers 23, 24 is also used as a part of a heat source for reheating the steam in the circulation line 3. The thermal efficiency in drying sewage sludge can be further increased.

  Further, when the sewage sludge having a water content of about 80% by weight is dried to finally form a dry sludge having a water content of about 10% by weight, when the water content is reduced to about 40% by weight, Whereas the fluidity becomes the lowest and hinders the smooth movement in the drying apparatus 1, according to this drying system, the moisture is evaporated in the first drying chamber 23 and the fluidity is lowered. After the secondary dewatered sludge is once extracted from the first drying chamber 23 and further removed into a secondary dewatered sludge whose fluidity has been improved by removing a part of the moisture by the uniaxial press 27, this is treated as the second drying chamber. Since it supplies to 24 and it is set as dry sludge, it becomes possible to make the said sewage sludge into dry sludge smoothly.

  At this time, by adding air to the primary dewatered sludge in the mixer 26 before the uniaxial compressor 27 and mixing it sufficiently, the gel form on the surface of the primary dewatered sludge is destroyed and the internal water drainage channel. Therefore, coupled with the high surface pressure during pressing by the uniaxial press 27, it is possible to effectively remove moisture from the primary dewatered sludge to obtain secondary dewatered sludge.

  Moreover, when a part of the water contained in the primary dewatered sludge is removed by the uniaxial press 27, the chlorine content (NaCl) contained in the primary dewatered sludge can also be removed together with the water. Even when the dried sludge as a product is put into the dry kiln and used as part of the fuel, the occurrence of harmful effects such as blocking of the preheater due to the chlorine content brought into the dry kiln is suppressed. be able to.

  Furthermore, in the said drying system, in the 1st and 2nd drying chambers 23 and 24 of the drying apparatus 1, since the water | moisture content contained in a sewage sludge or a secondary dewatering sludge is evaporated by indirect heating, it is 1st. The exhaust gas taken out from the second drying chambers 23 and 24 through the exhaust pipes 7a and 7b is only vapor evaporated from the sewage sludge or the secondary dewatered sludge. In addition, as described above, the secondary dewatered sludge supplied to the second drying chamber 24 has a moisture content less than that of the primary dehydrated sludge by removing water in advance in the uniaxial press 27. ing.

  For this reason, when the exhaust gas is drained to be purified, the amount of generated drain can be reduced, and the purification process is facilitated.

The obtained dried sludge, in order to contain a large amount of nitrogen content than fossil fuels such as coal, in the case of incineration in a dry kiln in example cement production facility, but the thermal NO _X occurs during hot combustion In this drying system, in the drain tank 17, the ammonia content contained in the separated drain can be effectively used as a denitration agent in the cement manufacturing facility.

  Furthermore, since the compressor 15 driven by the electric motor 16 is used as the auxiliary heating means in the reheating device 10, the overall equipment becomes compact without requiring large equipment such as an auxiliary boiler, and further thermal efficiency is increased. Can be improved. Moreover, by controlling the rotation speed of the electric motor 16, the temperature of the chlorofluorocarbon can be adjusted, so that the temperature of the steam supplied to the heating member 2 can be easily controlled.

  In addition, in the said embodiment, although demonstrated only about the case where sewage sludge was used as a water-containing sludge, this invention is not limited to this, It can use for the drying of the water-containing sludge of all the characteristics. Further, the dried sludge obtained in this drying system can be used as an incineration process or as a part of fuel in various incineration facilities, regardless of the dry kiln in the above-described cement manufacturing facility.

  Furthermore, in the said embodiment, although the partition 22 was provided in the drying apparatus 1 and the inside of the main body 1a was isolate | separated into the 1st drying chamber 23 and the 2nd drying chamber 24, it demonstrated to this. The same effect can be obtained even when the independent first and second drying apparatuses are arranged in series.

DESCRIPTION OF SYMBOLS 1 Drying device 2 Heating member 3 Steam (1st heat medium) circulation line (1st circulation line)
7a, 7b Steam exhaust pipe 10 Reheating device 11 Freon (second heat medium) circulation line (second circulation line)
12 Condenser (first heat exchanger)
13 Expansion valve 14 Evaporator (second heat exchanger)
15 Compressor (auxiliary heating means)
16 Electric motor 23 1st drying chamber (1st drying apparatus)
24 Second drying chamber (second drying device)
26 Mixer 27 Single screw press

Claims (5)

  A first drying device having a heating member that heats water-containing sludge by indirect heating with a first heat medium to evaporate water, and pressurizes primary dewatered sludge discharged from the first drying device. A uniaxial pressing machine that removes a part of the water, and a heating member that is dried sludge by heating the secondary dewatered sludge discharged from the uniaxial pressing machine by indirect heating with the first heat medium to evaporate the water. A first drying line comprising: a first circulation line that circulates and supplies the first heat medium to the heating members of the first and second drying apparatuses; and And a reheating device for reheating the first heat medium discharged from the first and second drying devices. A drying system for hydrous sludge, comprising:   The water-containing sludge drying system according to claim 1, wherein a mixer for adding a dewatering aid to the primary dewatered sludge and mixing the first dewatered sludge is disposed in a preceding stage of the uniaxial press.   The reheating device includes a second circulation line that circulates a second heat medium, and a second circulation line that is interposed in the second circulation line and heats the first heat medium to a supply temperature to the drying device. 1 heat exchanger, an expansion valve for adiabatically expanding the second heat medium discharged from the first heat exchanger, and the second heat medium passing through the expansion valve as the first and / or the first heat exchanger. A second heat exchanger that is heated by steam discharged from the second drying device, and a supply temperature of the second heat medium discharged from the second heat exchanger to the first heat exchanger The water-containing sludge drying system according to claim 1 or 2, further comprising an auxiliary heating means for heating to a temperature.   The water-containing sludge according to claim 3, wherein the auxiliary heating means is an electric compressor that adiabatically compresses the second heat medium discharged from the second heat exchanger to raise the temperature. Drying system.   5. The water-containing sludge drying system according to claim 3, wherein the first heat medium is steam and the second heat medium is chlorofluorocarbon.

Images