KR100851948B1 - Apparatus and method for drying organic sludge - Google Patents

Abstract

An apparatus and a method for drying organic sludge are provided to dry the organic sludge economically and efficiently by mixing the organic sludge with dry sludge and drying the sludge mixture, and to cope with various needs of users by recycling the organic sludge into various products. An apparatus for drying organic sludge comprises: a sludge supply part(10) for supplying organic sludge; a mixer(20) for mixing the organic sludge with dry sludge to form a sludge mixture; a rotary dryer(30) for drying the sludge mixture; a dust collector(40) for separating dry sludge and flue gas from the dried sludge mixture; a sorter(50) for sorting the separated dry sludge per particle diameter; and a product storage tank(60) for storing the sorted dry sludge, wherein the apparatus further comprises: a flue gas treater(80) into which the flue gas separated from the dust collector flows to remove impurities of the flue gas and enable the treated flue gas to be reused in a heat source facility(90) of the rotary dryer; and a circulation fan(70) installed between the dust collector and the flue gas treater to blow the flue gas forcibly.

Description

Apparatus and method for drying organic sludge

The present invention relates to an organic sludge drying apparatus and a drying method, and more particularly, organic sludges such as sewage sludge and purified water sludge are dried and pelletized, and these pelletized products are used as recycled fuels such as auxiliary fuels or cover materials. It relates to an organic sludge drying apparatus and a drying method that can be recycled.

In general, organic sludge is a microbial residue generated during the treatment of water, industrial water, industrial wastewater, sewage, and manure, and most of these components contain organic materials. Interest is on the rise.

Such organic sludge occurs about 7 million tons per year, of which sewage sludge corresponds to 3 million tons per year, 70% of which is treated with ocean dumping, and the recycling rate is very low, around 10%.

In addition, from 2011, the London Convention will prohibit the organic dumping of organic sludge, and the sludge that has been treated with marine dumping should be treated on land. Currently, the sludge recycling rate of organic sludge, which is about 10%, will be 70 until 2011. Policies are attempting to increase the percentage by up to about%.

To this end, various recycling laws are being financed, and the representative law is the Renewable Portfolio Standards (RPS) system, which is a mandatory use of renewable energy, which is a percentage of the total generation or sales volume of electricity generating companies or distributors. Is mandatory to cover renewable energy with renewable energy.

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. .

General conventional sludge treatment and recycling methods include solidification method, simple drying, composting, carbonization, and light weight aggregate method. The solidification method is a method of applying a large amount of solidifying agent to a landfill material after curing for several days. However, this method has a problem that the curing period is long and efficient replacement of odor occurrence is difficult, and the composting method has a lot of regulations to be resolved in the fertilizer management law, and it is difficult to create a demand source.

In addition, the carbonization method or lightweight aggregate method has a problem of very low economic efficiency. The conventional solidification treatment method has a disadvantage in that excessive treatment time is required when treating sludge and a large installation site is required.

The present invention has been made in order to solve the above-mentioned conventional problems, by mixing the organic sludge with dry sludge to dry, it is possible to economically and efficiently dry the sludge, and also to meet the various needs of the consumer The product can be recycled in various ways, and the produced dry sludge has little dust and odor, so it is easy to handle and transport, and it can be used as renewable fuel for thermal power plant auxiliary fuel, cement kiln auxiliary fuel, etc. It is an object of the present invention to provide an organic sludge drying apparatus and a drying method that can be recycled as a landfill daily soil material, soil improver, etc. by adding additional additives.

The present invention for achieving the above object, the sludge supply unit for supplying organic sludge; A mixer for mixing the organic sludge and the dry sludge to form a mixed sludge; A rotary dryer for drying the mixed sludge; A dust collector separating the dried sludge and the exhaust gas from the dried mixed sludge; A sorter for sorting the separated dry sludge by particle diameter; And a product storage tank for storing the sorted dry sludge.

In addition, the present invention further includes an exhaust gas processor for introducing the exhaust gas separated from the dust collector to treat impurities in the exhaust gas and reusing the treated exhaust gas in a heat source facility of the rotary dryer.

Between the dust collector and the exhaust gas treatment system of the present invention, a circulation fan for forcibly delivering exhaust gas is installed.

The exhaust gas treatment device of the present invention includes a heat exchanger for recovering a heat source of the exhaust gas, a wet cleaner for treating impurities in the exhaust gas, and a bag filter.

The mixer of the present invention constantly mixes the organic sludge supplied from the sludge supply unit with the dry sludge conveyed from the sorter at a ratio of 1: 3 to 1: 4 to form a mixed sludge having a water content of 20 to 30%.

The dust collector of the present invention removes dust and foreign matter by using a bag filter, and installs a primary partition at an inlet through which dry sludge flows to remove particles of a predetermined size or more.

The present invention supply step of supplying organic sludge; Mixing the organic sludge and the dry sludge to form a mixed sludge; A drying step of drying the mixed sludge; A dust collecting step of separating the dried sludge and the exhaust gas from the dried mixed sludge; Sorting the separated dry sludge by particle size; And a product storage step of storing the selected dry sludge.

In addition, the present invention further includes an exhaust gas treatment step of allowing the exhaust gas separated in the dust collecting step to process impurities in the exhaust gas and reusing the treated exhaust gas in the heat source equipment of the drying step.

In the mixing step of the present invention, the organic sludge having a water content of 70 to 90% and the dry sludge selected as a part thereof are mixed to form a mixed sludge having a water content of 20 to 30% and atomize.

In the drying step of the present invention, the mixed sludge is formed into a dry sludge having a water content of 10% or less using a three-pass drum dryer.

In the drying step of the present invention, a negative pressure (−) is always maintained in the dryer, and the oxygen concentration in the dryer is maintained at 8% or less.

In the sorting step of the present invention, the dry sludge having a particle diameter of 2 to 8 mm is selected and moved to a product storage step.

As described above, the present invention is not only to dry the sludge economically and efficiently by mixing the organic sludge with the dry sludge, but also to cope with the various needs of the consumer to be able to recycle a variety of products Provide effect.

In particular, the dry sludge produced according to the present invention has little dust and odor, so it is easy to handle and transport, and it can be used as renewable fuel for thermal power plant auxiliary fuel, cement kiln auxiliary fuel, etc., and an additive is added in the sludge supply unit. By putting it into the landfill daily cover material, it is effective to be recycled as soil improver.

The use of renewable energy from waste gas such as digestive gas or landfill gas generated during anaerobic digestion of organic sludge makes it possible to dry organic sludge very economically.

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 an organic sludge drying apparatus and a drying method according to an embodiment of the present invention.

As shown in FIG. 1, the organic sludge drying apparatus according to the present embodiment includes a sludge supply unit 10, a mixer 20, a rotary dryer 30, a dust collector 40, a separator 50, and a product storage tank 60. It includes.

The sludge supply unit 10 is composed of a sludge storage tank, a sludge discharger, a sludge conveying conveyor, a sludge feeder, a sludge conveying pump, an additive hopper, and the like, to supply organic sludge such as sewage sludge and purified water sludge to the mixer 20.

The sludge storage tank stores organic sludge having a water content of 70 to 90%, and an opening / closing inlet is installed to facilitate the introduction of organic sludge, and it is possible to adjust the weight and input amount of organic sludge by installing a meter.

The sludge discharger is a device that drives the organic sludge from side to side in order to discharge the sludge smoothly from the sludge reservoir, and is operated at regular intervals. The sludge conveying conveyor serves to transfer the organic sludge discharged from the sludge discharger to the sludge feeder, and the sludge feeder transfers a certain amount of organic sludge to the transfer pump by installing a rotary valve.

The transfer pump is a device for transferring the organic sludge to the mixer, and a mono pump is usually used, but a piston pump may also be used.

Additive hopper is a device for adding an additive to the organic sludge which stores the additive and puts it into the mixer 20 when the purpose of recycling the organic sludge dry matter is a soil improver or daily soil material. By controlling the speed, the amount of additive added is controlled.

The mixer 20 constantly mixes the organic sludge supplied from the sludge supply unit 10 with a part of dry sludge transferred from the sorter 50 at a mixing ratio of 1: 3 to 1: 4 so that the water content is 20. A mixed sludge of ˜30% is formed.

When the mixing ratio of organic sludge and dry sludge is smaller than 1: 3, the amount of organic sludge is increased and the water content of the mixed sludge increases, so that it takes excessive time for drying, and when it is larger than 1: 4, the amount of organic sludge is increased. Since the amount of organic sludge to be dried to decrease is reduced, it is preferable to use a mixing ratio of 1: 3 to 1: 4 because the treatment efficiency is lowered.

In addition, if the water content of the mixed sludge is greater than 30% as in the above, the drying time of the mixed sludge is excessive, and if the water content is less than 20%, the amount of organic sludge to be dried is reduced and the treatment efficiency is lowered. It is desirable to maintain a moisture content of%.

In the mixer 20, the rotor blades attached to the dual shaft are alternately rotated to mix organic sludge and dry sludge, and the angles of the rotor blades are formed different from each other to adjust the residence time of the mixed sludge. In particular, such a mixer can be atomized while mixing the organic sludge and the dry sludge to improve the drying efficiency of the mixed sludge introduced into the rotary dryer (30).

The rotary dryer 30 is a rotary drum type dryer, and the mixed sludge having a water content of 20 to 30% formed in the mixer 20 is dried by dry sludge having a water content of 10% or less. If the moisture content of the dry sludge is higher than 10%, the recyclability is degraded as regenerated fuel such as auxiliary fuel.

The driving speed of the rotary dryer 30 is rotated at 12 to 13 rpm per minute to form a circular sludge particle shape, and the inlet side of the rotary dryer 30 is formed in a venturimeter shape, and mixed sludge. It is desirable to increase the instantaneous flow rate at the inlet during the injection process so that the inlet can be inserted without clogging.

In addition, a temperature sensor is installed at the rear end of the rotary dryer 30 to automatically operate the temperature at the rear end at about 95 ° C., and a spray nozzle is installed at the front end of the rotary dryer 30 to provide the rotary dryer ( When the temperature at the rear end of 30) rises by 100 ° C. or more, it is preferable to spray a predetermined amount of water to maintain the temperature at the rear end in a predetermined range. In addition, by installing a pressure gauge at the front end of the rotary dryer (30) to maintain a negative pressure (-) is always formed in the dryer to prevent odor from occurring outside the rotary dryer (30), the oxygen meter is installed in the system It is desirable to ensure that the oxygen concentration of 8% or less is maintained.

The dust collector 40 separates the dried sludge and dry sludge from the dried mixed sludge, removes dust and foreign matter using a bag-filter, and installs a primary partition at an inlet in which the dry sludge is introduced. The above particles are removed.

In addition, it is preferable to install a discharge conveyor and a rotary valve in the dust collector 40 so that the transport amount of the dry sludge is constantly transferred to the sorter 50.

The sorter 50 sorts the dry sludge separated by the dust collector 40 by particle diameter, and is composed of a sorting distributor, a sorting conveying conveyor, an emergency discharge chute and a dry matter conveying conveyor.

The sorting distributor is capable of selecting and distributing dry sludge by dividing it into two or three by varying the size of the mesh by setting the upper limit of 8 mm to the lower limit of 2 mm for the particle size of the dry sludge. A part of the dry sludge having a particle diameter of 2 to 8 mm is transferred to the product storage tank 60 through a dry conveying conveyor, which may be transferred using an air transport hopper and an air circulation blower.

In addition, a portion of the dry sludge having a certain size or less and a dry sludge having a particle size of 2 to 8mm is transferred to the mixer 20 and mixed with organic sludge having a water content of 70 to 90% to prepare a mixed sludge having a water content of 20 to 30%. Conveyed to the mixer 20. At this time, it is preferable to install a damper in the sorter 50 so as to adjust the amount in order to make the mixing ratio constant. It is of course also possible to further configure an emergency discharge chute for carrying out dry sludge having a particle diameter larger than 8 mm and an emergency dry sludge.

Here, the reason for limiting the particle size of the dry sludge to 2 to 8mm is that, in the case of storing the finally dried dry sludge in the product storage tank 60, it can be stored while maintaining the optimum moisture in a suitable area, and can be recycled later This is because the convenience in use is increased. In other words, if the particle diameter is smaller or larger than the particle size, the optimum moisture is maintained or the recyclability is lowered.

The product reservoir 60 stores dry sludge having a particle diameter of 2 to 8 mm selected by the separator 50.

In addition, in the organic sludge drying apparatus of the present embodiment, the exhaust gas separated from the dust collector 40 is introduced to treat impurities in the exhaust gas, and the exhaust gas for reuse of the treated exhaust gas in the heat source facility 90 of the rotary dryer 30. It is preferable to further include a processor (80).

The exhaust gas processor 80 includes a heat exchanger for recovering a heat source of the exhaust gas, a wet cleaner and a bag filter for treating impurities in the exhaust gas.

The exhaust gas of about 95 ° C. introduced into the exhaust gas processor 80 is cooled to about 65 ° C. by the exhaust gas processor 80, and is then heated to a drying gas of about 400 to 450 ° C. through a heat exchanger of the heat source device 90. It will cycle. At this time, a part of the exhaust gas is put into the combustion chamber to be treated at a high temperature, and this high temperature treatment is for removing high concentration of odorous substances generated during sludge drying.

The exhaust gas processor 80 uses a wet cleaner and processes the bag gas using a bag filter and a bag filter to process the exhaust gas generated in each process. Wet cleaners remove water-soluble odors and dusts generated in the drying process to maintain a clean process.

In addition, between the dust collector 40 and the exhaust gas processor 80, a circulation fan 70 for forcibly delivering the exhaust gas is installed, and the dry sludge separated from the dust collector 40 is transferred to the separator 50, and the dust collector ( The exhaust gas separated in 40 is forcibly transferred to the exhaust gas processor 80 by the circulation fan 70 and processed.

In this case, the circulation fan 70 used is a dry sludge dried at a moisture content of 10% or less in the rotary dryer 30, but maintains a flow rate of about 10 to 20 m / sec to be transferred to the dust collector 40, and a damper. And an automatic control motor.

In addition, by installing a separate circulation dry hopper in the front stage of the product storage tank 60 of the organic sludge drying apparatus of the present embodiment by connecting with the secondary sludge drying apparatus (patent application No.:10-2007-89171) filed by the applicant Of course, driving is possible. In this case, more than 20% of the amount of energy used in the drying apparatus of this embodiment can be reduced.

The heat source facility 90 is composed of a combustion air supply fan, a burner, a combustion chamber, and a heat exchanger. The heat source facility 90 is supplied with recycled exhaust gas cooled by approximately 55 to 65 ° C. by the exhaust gas processor 80.

In addition, the burner having a small capacity may be an integral unit of the combustion air supply fan and the burner, the burner is typically used liquefied natural gas (LNG), but heavy oil, liquefied petroleum gas (LPG) may be used.

In particular, when using renewable energy generated from waste gas such as digested gas or landfill gas generated during anaerobic digestion of organic sludge to reduce operating costs, organic sludge can be dried very economically.

In the combustion chamber, it is preferable that the LNG is completely burned and the high concentration of malodorous substances generated in the drying process is combusted so that no malodors are generated in the process.

The heat exchanger raises the drying air cooled at around 55 to 65 degrees while the combustion chamber air at 650 to 750 degrees Celsius is cooled to 120 to 180 degrees Celsius, and then to the drying air at about 400 to 450 degrees Celsius. Combustion air is discharged to the outside by the combustion air exhaust fan.

At this time, the part of the combustion air discharged is installed in the drying process by installing an automatic control valve in the heat exchanger to maintain the oxygen concentration in the drying process below 8%. The reason why the oxygen concentration in the drying process is kept below 8% is that when the oxygen concentration is higher than 8%, the risk of explosion in the drying process increases.

In addition, the organic sludge drying apparatus of the present embodiment is a utility facility for supplying water and recovering cooling water to a wet cleaner, a dryer, a water spray, and the like, and an air and hydraulic system capable of driving a mixer, a dryer, a dust collector and a separator. It includes utility facilities such as facilities.

Hereinafter, the organic sludge drying method according to a preferred embodiment of the present invention will be described in more detail.

Drying method of the organic sludge according to the present embodiment includes a supply step, mixing step, drying step, dust collection step, screening step and product storage step.

In the supplying step, organic sludge, such as sewage sludge and purified water sludge, is supplied from the sludge supply unit 10 to the mixer 20.

In the mixing step, the organic sludge having a water content of 70 to 90% in the mixer 20 and a part of the dry sludge selected in the sorting step are mixed to form a mixed sludge having a water content of 20 to 30% and atomize.

Drying step, using the 3-pass drum dryer (Patent Application No.:10-2007-140431) filed by the applicant as a rotary dryer (30), the sludge of 20-30% of water content of dry sludge of 10% or less of water content To dry. In addition, the drying step is to maintain the negative pressure (-) is always formed in the dryer, and to maintain the oxygen concentration in the dryer to 8% or less. The reason why the oxygen concentration is kept below 8% is that when the oxygen concentration is higher than 8%, the risk of explosion in the dryer increases.

In the dust collecting step, the mixed sludge dried in the rotary dryer 30 by the exhaust gas treatment device (Patent Application No.:10-2007-126038) filed by the present applicant as the dust collector 40 is separated into dry sludge and exhaust gas.

In the sorting step, the dry sludge separated by the dust collector 40 is sorted by the particle diameter by the sorter 50. The dry sludge having a particle diameter of 2 to 8 mm is sorted and moved to the product storage step. Therefore, the product storage step stores the dry sludge having a particle diameter of 2 to 8 mm selected by the separator 50.

The reason for limiting the particle size of the dry sludge to 2 to 8 mm is that, when storing the finally dried dry sludge in the product storage tank 60, it can be stored while maintaining the optimum moisture in a suitable area, and when reused later This is because convenience is increased. In other words, if the particle diameter is smaller or larger than the particle size, the optimum moisture is maintained or the recyclability is lowered.

In addition, the exhaust gas separated by the dust collector 40 in the dust collecting step is forcibly delivered by the circulation fan 70 and flows into the exhaust gas processor 80 to recover the latent heat of the exhaust gas, process impurities, and dry the treated exhaust gas. It is preferable to further include an exhaust gas treatment step for reuse in the heat source facility (90) of the step.

In the exhaust gas treatment step, the exhaust gas of about 95 ° C. introduced into the exhaust gas processor 80 from the dust collector 40 is cooled to about 65 ° C. through the exhaust gas treatment device, and is about 400 to 450 ° C. by the heat exchanger of the heat source device 90. It is circulated by heating with a drying gas of. At this time, a part of the exhaust gas is injected into the combustion chamber to be treated at a high temperature. Such high temperature treatment removes a high concentration of odorous substances generated during sludge drying.

Therefore, the dry sludge produced in the apparatus and method of the present embodiment has a calorific value of 3,000 to 4,500 kcal / kg, which is similar to the anthracite calorific value, so that it can be utilized as auxiliary fuel for thermal power plants, and is widely used for renewable fuels such as cement kiln auxiliary fuel.

In addition, when an additive hopper is additionally installed in the sludge supply unit 10 to manufacture a dry sludge by adding a certain amount of additives, it is possible to recycle the soil improver, a landfill daily cover material, and the like.

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 an organic sludge drying apparatus and a drying method according to an embodiment of the present invention.

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

10: sludge supply part 20: mixer

30: rotary dryer 40: dust collector

50: sorter 60: product reservoir

70: circulation fan 80: flue gas handler

90: heat source equipment

Claims (12)

delete delete A sludge supply unit for supplying organic sludge; A mixer for mixing the organic sludge and the dry sludge to form a mixed sludge; A rotary dryer for drying the mixed sludge; A dust collector separating the dried sludge and the exhaust gas from the dried mixed sludge; A sorter for sorting the separated dry sludge by particle diameter; And It includes a product storage tank for storing the sorted dry sludge, The exhaust gas separated from the dust collector is introduced to process the impurities of the exhaust gas, and further comprising an exhaust gas processor to reuse the treated exhaust gas in the heat source equipment of the rotary dryer, Organic sludge drying apparatus, characterized in that the circulation fan for forcing the delivery of exhaust gas is installed between the dust collector and the exhaust gas treatment. The method of claim 3, wherein The exhaust gas treatment device is an organic sludge drying apparatus comprising a heat exchanger for recovering a heat source of the exhaust gas, a wet cleaner and a bag filter for treating impurities in the exhaust gas. The method of claim 3, wherein The mixer is characterized in that to form a mixed sludge having a water content of 20 to 30% by constantly mixing the oil-bearing sludge supplied from the sludge supply unit and the dry sludge conveyed from the sorter at a ratio of 1: 3 to 1: 4. Organic sludge drying apparatus. The method of claim 3, wherein The dust collector is a bag-filter (bag-filter) to remove dust and foreign matter, the organic sludge drying apparatus, characterized in that to remove the particles larger than a predetermined size by installing a primary partition at the inlet through which the dry sludge flows. A supply step of supplying organic sludge; Mixing the organic sludge and the dry sludge to form a mixed sludge; A drying step of drying the mixed sludge; A dust collecting step of separating the dried sludge and the exhaust gas from the dried mixed sludge; Sorting the separated dry sludge by particle size; And A product storage step of storing the selected dry sludge, The mixing step, the organic sludge drying method characterized in that the organic sludge having a water content of 70 to 90% and the selected portion of the dry sludge is mixed to form a mixed sludge having a water content of 20 to 30% by atomization. The method of claim 7, wherein And a flue gas treatment step of treating the impurities in the flue gas by introducing the flue gas separated in the dust collecting step and reusing the treated flue gas in the heat source equipment of the drying step. delete The method according to claim 7 or 8, The drying step, the organic sludge drying method characterized in that to form a dry sludge having a water content of 10% or less using a three-pass drum dryer. The method according to claim 7 or 8, The drying step, the organic sludge drying method characterized in that to maintain the negative pressure (-) is always formed in the dryer, the oxygen concentration in the dryer to be maintained at 8% or less. The method according to claim 7 or 8, The sorting step, the organic sludge drying method, characterized in that for drying the sludge having a particle diameter of 2 to 8mm to move to the product storage step.

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