KR100812707B1 - Apparatus and method for drying sludge - Google Patents

Abstract

An apparatus for drying sludge is provided to secure various utilizations by manufacturing articles from sludge mixtures produced according to types of additives, and reduce the drying time of sludge by efficiently drying sludge with 80% of a water content into a sludge mixture with not more than 10% of a water content within a short time, and a method for drying sludge using the apparatus for drying sludge is provided. An apparatus for drying sludge includes: a mixer(130) for forming pellets from a sludge mixture in which sludge and additives are mixed; a drying equipment(140) for drying the sludge mixture that has been formed into the pellets in the mixer; a condensing equipment(150) connected to the drying equipment to condense water contained in the air by cooling wet air in the drying equipment; a transfer equipment for transferring the sludge mixture dried in the drying equipment; and a product storage tank(210) for storing the dried sludge mixture conveyed by the transfer equipment, wherein the condensing equipment is at least one of a direct condensing equipment using a water spray and an indirect condensing equipment using a cooling pipe, and the apparatus for drying sludge additionally includes a sorter for sorting the dried sludge mixture in the drying equipment according to the size of the dried sludge mixture.

Description

Apparatus and method for drying sludge

The present invention is a sludge drying process consisting of a sludge storage tank, an additive storage tank, a mixer, a drying device, a sorting distributor, a conveying device, a product storage tank, a heat exchanger, a condenser, and a conveying device, and pellets mixed sludge having a water content of 30 to 45% ( It is to provide a sludge drying apparatus for producing a dry sludge having a moisture content of about 10% by pelletizing, that is, baked at a high temperature to harden.

In general, sludge referred to in the present invention refers to microbial residues generated during the treatment of water, industrial water, industrial wastewater, sewage, and manure. The main components of these sludges contain organic substances, and most of them are disposed of in recent years. People's perceptions are changing from recyclable materials to recyclable materials.

Most of the sludge is generated in the form of a dehydrated cake having a water content of 75 to 85%, the organic material of the sludge except the water is usually 40 to 80% in a variety of ranges, resulting in a calorific value It ranges from 2,500 kcal / kg up to 4,500 kcal / kg.

For example, as of 2005, sludge is generated at 6.9 million tons per year in Korea, most of which is being dumped or incinerated. Therefore, by causing various social problems such as environmental pollution, the government is making efforts to increase the recycling rate of organic sludge on land by 70% by creating a ban on ocean dumping of organic sludge by 2011.

In general, the generation of household sewage and industrial wastewater has also increased greatly for various reasons such as economic development, population growth, and improved living standards. Accordingly, in order to prevent water pollution of major rivers and rivers, the facilities of sewage and wastewater treatment facilities, which are the basic facilities for water quality improvement, are also inevitably increasing, and the amount of sewage and wastewater sludge, which is a secondary by-product of incidental water, is gradually increasing. .

Most of the sewage sludge produced is treated by landfill and dumping at sea. However, in the case of simple landfill, from July 2003, direct reclamation of sewage treatment plant sludge with a capacity of more than 10,000 tons / day has been prohibited due to the revision of the Waste Management Act Enforcement Rule.

Accordingly, the proportion of marine dumping is increasing, but in this case, there is a concern that it may cause pollution of the marine ecosystem, such as eutrophication due to excessive organic substances, algae growth and oxygen depletion due to red tide occurrence in which a large amount of vegetable nutrients are introduced. Korea entered into the London Convention, the international convention on the prohibition of waste dumping on December 21, 1993, and has been in effect since January 19, 1994. The government has tightened marine dumping by tightening regulations such as changing the law.

In addition, incineration, which is considered as a sludge treatment method, has a problem of air pollution due to generation of secondary environmental pollutants as well as high incineration facility construction and operation costs. As a result, many civil complaints of neighboring residents have occurred, which is very difficult to apply.

Therefore, in the future, the sludge treatment method is urgently required to actively recycle beyond the simple treatment stage such as landfill, ocean dumping, incineration. Therefore, as a method of recycling sludge, there is a method of using it as a raw material of fertilizer, fuel, and cement by using the solidification method, simple drying, composting, carbonization, and light weight aggregate method, but the above-mentioned methods have many problems. .

More specifically, the solidification method is a method of injecting a large amount of solidifying agent to be used as a landfill material after a curing process for several days, this method has a long curing period and odor occurs, it is difficult to cope efficiently Was hugging.

In addition, the composting method has a lot of regulations to be resolved in the fertilizer management law, there was a problem that it is difficult to create a demand source. And, the carbonization method or lightweight aggregate method had a problem of very low economic efficiency.

In addition, when the sludge is treated by a conventional solidification treatment method, it takes a long time to process and a lot of sites are required.

In addition, in order to efficiently dry the sludge as described above, there is a problem that the development of a drying apparatus that can dry the sludge more effectively must precede.

The present invention has been made in order to solve the above-mentioned conventional problems, to provide a sludge drying apparatus that can secure a variety of applications by securing economic efficiency and commercialized mixed sludge produced according to the type of additives There is this.

In addition, sludge storage tank, additive storage tank, mixer, drying device, sorting distributor, conveying device, product storage tank, conveying device, etc., through which the sludge of 80% moisture content and dried mixed sludge having a water content of 10% or less in a short time It is an object of the present invention to provide a sludge drying apparatus capable of shortening the drying time of sludge and producing a product in accordance with various demands of the customer by providing an efficient sludge drying apparatus.

The present invention for achieving the above object, the mixer for pelletizing the mixed sludge mixed with the sludge, the drying device for drying the mixed sludge pelletized in the mixer, and the drying device connected to the drying device A condenser for condensing moisture contained in the air by cooling the humid air therein; a conveying device for conveying the dried mixed sludge in the drying device; and a product storage tank for storing the dried mixed sludge transported by the conveying device. It is characterized by including.

More preferably, the condenser uses at least one of a direct condenser using a water spray, and an indirect condenser using a cooling tube.

More preferably, it further comprises a sorting distributor for classifying the dried mixed sludge in the drying apparatus according to the size.

More preferably, it further comprises a conveying device for conveying a portion of the mixed sludge selected by the sorting distributor to the mixer.

More preferably, characterized in that it further comprises a discharge chute for discharging a portion of the mixed sludge selected by the sorting distributor to the outside.

More preferably, characterized in that it further comprises a blower for forced circulation of the air from which water is removed by the condenser.

More preferably, it further comprises a heat exchanger for supplying to the drying apparatus by raising the temperature of the air from which water is removed by the condenser.

More preferably, the sludge drying method comprises the steps of: (a) mixing the sludge and the additive in a mixer to pelletize; (b) transferring the pelletized mixed sludge to a drying apparatus; (c) cooling the humid air in the drying apparatus to condense and dry moisture contained in the air; (d) conveying the dried mixed sludge in the drying apparatus; (e) storing the dried mixed sludge conveyed by the conveying apparatus.

More preferably, the step (c) by supplying heat to the air condensed water, characterized in that it further comprises the step of heat exchange to reduce the relative humidity.

More preferably, after the step (c) further comprises the step of sorting the mixed sludge according to the size, the step (d) is to transfer only if the size of the sorted mixed sludge sorted within the preset range It is characterized by.

More preferably, the mixed sludge is returned to the mixer when the size of the mixed sludge is less than the lower limit of the preset range, and discharged to the outside when the mixed sludge exceeds the upper limit.

More preferably, the size of the mixed sludge is 2 to 8mm.

More preferably, the water content of the sludge mixed with the additive of step (a) is characterized in that 75 to 85%.

More preferably, the mixed sludge moisture content of the mixer outlet in step (a) is 30 to 45%.

More preferably, the mixed sludge moisture content of the drying apparatus outlet in step (c) is 10 to 15%.

As described above, the present invention is applied to the drying of the sludge, not only can the sludge dry more economically and efficiently, but also differently added additives to be able to quickly respond to the requirements of the demand of the product demand By efficiently drying the organic sludge, which is currently mostly dumped at sea, it is possible to commercialize pelletized mixed sludge to produce various places such as auxiliary fuel of thermal power plant, auxiliary fuel of cement kiln, landfill agent and soil improver. It provides an effect that can be utilized in.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a block diagram showing a sludge drying apparatus of the present invention.

As shown in FIG. 1, the sludge drying apparatus of the present invention is composed of a sludge storage tank, an additive storage tank, a mixer, a drying apparatus, a sorting distributor, a conveying apparatus, a product storage tank, a condensing apparatus, and a conveying apparatus.

The sludge storage tank 110 is a device for storing sludge with a water content of 75% to 85% of the lower limit, and is composed of a sludge discharger 111, a sludge conveying screw 112, and a sludge conveying pump 113.

In detail, the sludge discharger 111 is a device for driving the sludge to the left and right so that the sludge is smoothly discharged from the sludge storage tank 110, the sludge conveying screw 112 transfers the discharged sludge to the sludge conveying pump 113, The sludge conveying pump 113 is a device for transferring the sludge to the mixer (130). On the other hand, the sludge transfer pump 113 is typically used a mono pump as applied to the present invention.

The additive storage tank 120 is a device for storing the additive and injecting the additive into the mixer to be mixed with the sludge, and may use different additives according to the type and demand of the produced product, and the lower portion of the rotary valve 121 It is provided, it is possible to control the amount of the additive to be added by controlling the rate at which the additive is added. In some cases, the sludge is dried in a drying apparatus without adding an additive.

In this case, the type of the additive to be added to the additive storage tank 120 is not limited to a specific one, and is mixed with the sludge and finally delivered to the workplace and used in the workplace, for example, supplied to the thermal power plant as an auxiliary fuel In the case of use, slaked lime is used as an additive to increase calorific value, and when used as a soil improver or cover material of landfill, organic materials such as sawdust or rice bran may be used as an additive to fertilize soil.

The mixer 130 is a place where the sludge with a water content transferred from the sludge storage tank 110 is a lower limit of 75% to an upper limit of 85% and an additive transferred from the additive storage tank 120 is mixed. At this time, while the mixing process is performed in the mixer 130, the water content of the mixed sludge is adjusted to the lower limit 30% to the upper limit 45%. Then, the mixed sludge is formed in the form of pellets (pellets) in the mixer 130 while undergoing a reprocessing process in the transfer process is introduced into the drying apparatus 140.

The drying apparatus 140 is a device for drying the mixed sludge having a water content of 30% to a 45% upper limit of the final moisture content to a lower limit of 10% to 15% of the upper limit of the final product. Weighing device 141, a rotary valve 142 and a conveying conveyor 143 for transporting the dry matter discharged by a predetermined amount.

Then, the condenser 150 is installed outside to be connected to the drying device 140 to condense the moisture contained in the air by cooling the humid air inside the drying device 140, and the condenser 150. It is connected to and forced circulation by the blower 160, the air from which moisture is removed by the condenser 150.

Then, the temperature of the air from which the moisture is removed by the condenser 150 is increased by the heat exchanger 170 which recycles the moisture and the odor-removed air to increase the temperature, and reduces the relative humidity. Supply to the drying device (140).

The condenser 150 is a device that is connected to the drying device 140 to remove moisture and odorous substances coming out of the drying process, and when the humid air of about 35 ° C. generated during the drying process is cooled to 25 ° C., the dew point may be increased. It is lowered to condense and remove moisture contained in the air.

Here, the condenser 150 may use at least one of a direct condenser using a water spray and an indirect condenser using a cooling tube.

In addition, the air from which the water is removed is circulated in the heat exchanger 170 to increase the temperature to reduce the relative humidity in the air, and consists of a system for circulating again in the drying process. At this time, the hot air circulation uses a forced circulation device, and can control the wind speed and the air volume by using a control button such as a switch.

The heat source used in the present invention is not particularly limited, but in general, conventional ones such as LNG, heavy oil, and the like are used, and in some cases, it may be more economical to use waste heat of an incineration plant or an industry.

The mixed sludge dried in the above manner is transferred to and stored in the product storage tank 210 through the sorting distributor 180. At this time, if the size of the mixed sludge sorted by the sorting distributor 180 is less than the lower limit value is transferred back to the mixer 130 by the conveying device 190, the conveying device 200 when the lower limit to the upper limit value. It is transported to the product storage tank 210 by, and when the upper limit value is exceeded is discharged to the outside by the discharge chute 220.

Here, the size of the mixed sludge is 2 to 8mm. However, since the above-mentioned range is only one embodiment to which the present invention is applied, there is no need to limit it to the above-described range, and it may be manufactured to be flexible and adjustable according to where the product is used.

In an embodiment, when the size of the product is set to the sorting distributor 180 to store the pelletized mixed sludge having a size of 2 to 8 mm in the product storage tank 210, pelletizing by the conveying device 190, If the size of one finally dried mixed sludge is smaller than 2 mm, it is re-transmitted to the mixer 130 for reprocessing into pelletized mixed sludge of 2 to 8 mm in size. Then, the small size is remixed to increase the size, and then transferred to the sorting distributor 180 to reselect.

And, if the size is larger than 8mm, it is discharged to the outside by the discharge chute 220.

The reason for specifying the size of the pelletized finally dried mixed sludge to 2 to 8 mm is to maintain optimal moisture in a suitable area when the finally dried mixed sludge is stored in the product storage tank 210. This is because it can be stored and reused in the future increases convenience for use.

In addition, when using the mixed sludge produced as a finished product is only for improving the aesthetic appearance and packaging easily as a product for transport, therefore, there is no need to specifically limit the size as mentioned above.

In addition, when an emergency occurs due to a malfunction of the machine or another cause, all the sludge that has been undergoing a drying process in the machine is discharged to the outside through the emergency outlet 230 while the conveying conveyor is reversely rotated.

Hereinafter, the operation and action of the sludge drying method according to the present invention.

First, the sludge having a water content of 75 to 85% stored in the sludge reservoir and the additive stored in the additive device are pelletized while mixing in the mixer. Then, the moisture content of the mixed sludge at the outlet of the mixer is 30 to 45%.

The pelletized mixed sludge is then transferred to a drying apparatus.

Then, the humid air inside the drying apparatus is cooled to condense and dry moisture contained in the air.

Then, heat is supplied to air condensed with moisture to reduce relative humidity.

Then, the dried mixed sludge inside the drying apparatus is sorted and sorted according to the preset size in the sorting distributor, and then transferred to the conveying apparatus, the discharge chute and the product storage tank, respectively. At this time, the mixed sludge moisture content at the outlet of the drying apparatus is 10 to 15%.

Then, when the size of the sorted mixed sludge is within the preset range, the dried mixed sludge conveyed by the transfer device is stored in the product storage tank.

Here, when the size of the mixed sludge is less than the lower limit of the preset range, the mixed sludge is returned to the mixer through a conveying device, and when the mixed sludge is between the lower limit and the upper limit, it is stored in the product storage tank, and when the upper limit exceeds the upper limit, it is discharged to the outside through the discharge chute. Discharge.

At this time, it is assumed that the size of the mixed sludge is 2 to 8mm. The reason for limiting the size as described above is as mentioned above.

Tables 1 to 3 below show the sludge drying experiment data according to the hot air temperature of the sludge drying apparatus using the sludge drying apparatus of the present invention.

time Dryer Inlet Temperature Condenser Inlet Temperature Condenser Outlet Temperature Inlet humidity Condenser Inlet Humidity Condenser Outlet Humidity Condenser Inlet Speed Condenser Outlet Speed Effluent Temperature Influent Temperature Outside humidity Outside temperature weight Water content min ℃ ℃ ℃ % % % m / s m / s ℃ ℃ % ℃ kg % 0 64.12 39.8 37.2 19.68 100 100 14.88 8.04 22.1 22.2 43.86 26.16 88.9 30.0 60 75.69 41.2 37.5 17.05 100 100 13.84 9.67 27.9 23.5 44.29 25.48 86.8 28.3 120 77.99 42 38 15.43 100 100 14.43 9.21 28.6 23.5 47.81 23.93 83.8 25.7 180 76.71 42.2 37.2 16.35 100 100 14.6 10.12 27.5 22.7 48.7 23.77 80.6 22.8 240 76.29 44.2 38 17.66 100 100 14.64 9.92 27.3 22.6 49.46 22.79 77.6 19.8 300 74.89 46.3 38.1 17.95 100 100 14.6 10.2 25.5 22.1 59.54 21 75 17.0 360 74.3 48.5 38.6 17.93 77.4 97.2 14.4 9.87 25.8 21.8 69.23 18.94 72.7 14.4 420 74.79 50.8 39.1 16.87 74.4 89.0 15.17 10.55 25 21 81.33 16.79 70.7 12.0

Table 1 shows a sludge drying experiment using a direct condenser at a hot air temperature of 75 ° C., and mixed sludge prepared at an initial water content of 30% with a drying device to prepare a dry sludge having a water content of about 10%. At this time, the time required is about 7 hours, and the amount of water evaporation per hour can be known by calculating the reduced weight per hour. That is, (88.9-70.7) / 7 = 2.6kg / hr, considering the error range is 2.67-2.95 kg / hr range.

time Dryer Inlet Temperature Condenser Inlet Temperature Condenser Outlet Temperature Inlet humidity Condenser Inlet Humidity Condenser Outlet Humidity Condenser Inlet Speed Condenser Outlet Speed Effluent Temperature Influent Temperature Outside humidity Outside temperature weight Water content min ℃ ℃ ℃ % % % m / s m / s ℃ ℃ % ℃ kg % 0 73.9 34.33 26.96 10.86 100 100 13.09 14.34 25.4 22 54.97 21.64 89.1 30.0 60 76.5 27.03 28.36 10.64 100 100 12.9 14.25 26.7 20.9 60.69 19.03 86.2 27.6 120 74.87 24.21 25.16 11.15 100 100 14.17 13.54 25 20.6 81.08 16.46 82.9 24.8 180 74.29 27.93 24.83 10.65 100 100 13.33 13.65 25.1 20.7 78.06 17.42 79.8 21.8 240 73.5 32.35 24.06 12.76 100 100 14.62 15.73 25 20.6 84.09 16.08 76.8 18.8 300 75.48 40.61 22.76 12.35 75.95 97.35 13.79 11.54 25.5 20.7 85.02 16.14 74.4 16.2 360 74.39 43.22 22.55 13.44 65.45 95.46 14.24 11.95 25.4 20.6 91.2 14.67 72.2 13.6 420 75.02 45.76 21.97 12.52 62.83 93.21 13.56 12.84 24.7 20.5 87.43 13.86 70.3 11.3

Table 2 shows a sludge drying experiment using an indirect condenser at a hot air temperature of 75 ° C., and mixed sludge prepared at an initial water content of 30% with a drying device to prepare dry sludge having a water content of about 10%. At this time, the time required is about 7 hours, by the same method as the calculation method of Table 1 the amount of water evaporation per hour is 2.54-2.95kg / hr.

time Dryer Inlet Temperature Condenser Inlet Temperature Condenser Outlet Temperature Inlet humidity Condenser Inlet Humidity Condenser Outlet Humidity Condenser Inlet Speed Condenser Outlet Speed Effluent Temperature Influent Temperature Outside humidity Outside temperature weight Water content min ℃ ℃ ℃ % % % m / s m / s ℃ ℃ % ℃ kg % 0 120 46.8 37.3 14.76 100 100 12.38 7.34 29.2 23.7 81.61 25.25 65.2 32.3 60 120 53.1 40.1 13.85 100 100 11.89 6.72 36.4 25.3 75.17 26.96 60.8 27.4 120 120 59.7 40.9 12.25 100 100 11.6 6.67 37.8 25.6 52.27 35.63 56.2 21.4 180 120 66.4 40.3 10.46 100 100 11.66 6.75 38.2 26.2 51.05 34.84 52.3 15.6 240 120 70.2 40.1 10.55 100 100 11.52 6.76 38.2 26 56.54 31.75 49.1 10.1

Table 3 shows a sludge drying experiment using a drying apparatus at a hot air temperature of 120 ° C. to dry mixed sludge produced at an initial water content of 30% with a drying device to prepare dry sludge having a water content of about 10%. At this time, the time required is about 4 hours, the amount of water evaporation per hour by the same method as the calculation method of Table 1 is 4.0-4.3kg / hr. At this time, the condenser is an indirect condenser.

However, the condenser may optionally use any one of an indirect condenser or a direct condenser.

The present invention described above can be embodied in many other forms without departing from the spirit or main features thereof. Therefore, the above embodiments are merely examples in all respects and should not be interpreted limitedly.

1 is a block diagram showing a sludge drying apparatus of the present invention.

<Description of the symbols for the main parts of the drawings>

110: sludge storage tank 120: additive storage tank

130: mixer 140: drying device

180: sorting distributor 190: conveying device

200: transfer device 210: product storage tank

220: discharge chute

Claims (15)

delete delete A mixer for pelletizing the mixed sludge in which the sludge and the additive are mixed; A drying apparatus for drying the mixed sludge pelletized in the mixer; A condenser connected to the drying device to condense the moisture contained in the air by cooling the humid air in the drying device; A conveying apparatus for conveying the dried mixed sludge in the drying apparatus; And A product storage tank for storing the dried mixed sludge transferred by the transfer device; Including, The condenser uses at least one of a direct condenser using a water spray and an indirect condenser using a cooling tube, A sorting distributor for classifying the dried mixed sludge in the drying apparatus according to the size; Sludge drying apparatus further comprises a. The method of claim 3, wherein A conveying apparatus for conveying a part of the mixed sludge sorted by the sorting distributor to the mixer; Sludge drying apparatus further comprises a. The method of claim 3, wherein A discharge chute for discharging a portion of the mixed sludge selected by the sorting distributor to the outside; Sludge drying apparatus further comprises a. The method of claim 3, wherein A blower forcibly circulating air from which moisture is removed by the condenser; Sludge drying apparatus further comprises a. The method of claim 3, wherein A heat exchanger which raises a temperature of air from which moisture is removed by the condenser and supplies it to the drying apparatus; Sludge drying apparatus further comprises a. delete (a) mixing the sludge and the additive in a mixer to pelletize; (b) transferring the pelletized mixed sludge to a drying apparatus; (c) cooling the humid air in the drying apparatus to condense and dry moisture contained in the air; (d) conveying the dried mixed sludge in the drying apparatus; (e) storing the dried mixed sludge conveyed by the conveying apparatus; Supplying heat to air condensed with moisture in step (c), thereby reducing heat exchange rate; Sludge drying method characterized in that it further comprises. The method of claim 9, After the step (c) further comprises the step of sorting the mixed sludge according to the size, the step (d) is characterized in that the sludge is transported only if the size of the sorted mixed sludge within the predetermined range Drying method. The method of claim 10, If the size of the mixed sludge is less than the lower limit of the predetermined range, the sludge drying method characterized in that it is returned to the mixer, if the upper limit exceeds the upper limit. The method of claim 11, Sludge drying method characterized in that the size of the mixed sludge is 2 to 8mm. The method of claim 9, Sludge drying method characterized in that the water content of the sludge mixed with the additive in the step (a) is 75 to 85%. The method of claim 9, Sludge drying method characterized in that the mixed sludge moisture content of the mixer outlet in step (a) is 30 to 45%. The method of claim 9, Sludge drying method characterized in that the mixed sludge moisture content of the drying apparatus outlet in step (c) is 10 to 15%.

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