KR100485222B1 - Equipment system for forming superlight-weight aggregate from sewage and wastewater sludge - Google Patents

Abstract

The present invention relates to a system for recycling sewage and wastewater sludge into ultra-light aggregates having micropores, and more particularly, the present invention has a cohesiveness of the sludge in treating sludge generated in a sewage terminal treatment plant or a wastewater treatment plant. Mixed with clay and foamed incineration ash, dried to 25 to 40% water content in the sludge, mixed homogeneously in the mixer, and then compressed to the mixed sludge to remove the pores inside the sludge to a certain strength Palletized into a sphere having a (pellet), using a counter-current rotary kiln firing to 950 ~ 1300 ℃ to provide a system for producing a super lightweight aggregate having a large number of micropores. The ultra-light aggregate produced in this way can be widely used as raw materials for civil engineering and building materials because it has economical efficiency as well as excellent quality with low specific gravity, insulation effect and high hardness. Therefore, the system according to the present invention is a useful invention that is environmentally friendly and more economical because it makes it possible to practically mass-process sludge, which is very difficult to treat conventionally, and manufacture building materials by utilizing sludge which is the cause of environmental pollution.

Description

EQUIPMENT SYSTEM FOR FORMING SUPERLIGHT-WEIGHT AGGREGATE FROM SEWAGE AND WASTEWATER SLUDGE}

The present invention relates to a system for recycling sewage and wastewater sludge into ultra-light aggregates, and more particularly, to treating sludge generated in a sewage terminal treatment plant or a wastewater treatment plant, the sludge has clays in the dryer and After mixing with an incineration material having effervescent properties, the water content of the sludge is dried to 25 to 40%, homogeneously mixed and compressed in a mixer to remove pores inside the mixed sludge, and then pelletized into a sphere. The present invention relates to a system for producing an ultralight aggregate having a large number of micropores by firing to 950-1300 ° C. using a rotary kiln.

Conventional sewage sludge has been mostly treated depending on ocean dumping and landfill, but there is a problem of causing secondary environmental pollution such as marine pollution, odor, leachate generation. In addition, the method of treating the raw material of cement after drying the sewage sludge also has a problem of lack of economic feasibility due to high secondary pollution and treatment cost during transportation and treatment of the dry sludge.

On the other hand, the system for incineration after drying, which is recently increasing for the treatment of sludge has problems such as civil complaints and high facilities and operating costs due to the problem of disposal of incineration ash and odors remaining as minerals.

In order to solve these problems, US Patent US RE34,775 proposes a method of recycling sewage sludge by mixing sewage sludge with fly ash to be fired at high temperature to prevent the discharge of harmful substances such as heavy metals, and producing it as aggregate. However, even in this case, in the installation process, the problem of odor generation of sewage and wastewater sludge and the aggregate size produced by the mixing of sludge and fly ash are uneven, the pores formed are irregular, and the strength of the aggregate is remarkably decreased, resulting in poor quality as aggregate. There is an inefficiency problem and it has not been put to practical use.

In addition, Korean Patent Publication No. 2001-47461 proposes a system for recycling a sludge into lightweight aggregate, and its configuration includes sludge drying unit, metering unit, particle size adjusting unit, drying unit, sintering unit, cooling discharge unit, and gas. Although it consists of a purification section, this patent has the following drawbacks and is not put to practical use.

First, in the sludge drying process, sludge and hot gas are directly contacted in the pre-dryer and the incinerator, and this method forms a dead zone by drying only the outer surface of the sludge and moisture inside. Since it is difficult to transport and has partial drying, it is impossible to form uniform pores when forming the pallet, so it is difficult to have suitable strength and quality as aggregate, and also three stages such as pre-drying step and first and second incineration step. There is an uneconomical problem due to the process.

Secondly, in the weighing process, the mixing ratio of sludge and additives is 2 to 3% by weight of sludge, 6 to 7% by weight of ocher, and 1% by weight of feldspar. Due to the inability to use the combustion heat of the organic material of the sludge itself, it is uneconomical to use a lot of auxiliary fuel, and there is a problem in that the strength of the produced pallet is weakened due to irregular pores generated during mixing.

Third, in the particle size adjusting process, there are various problems such as the size of the manufactured pallet, the complexity of the sorting, crushing and re-transfer process, the loss of raw materials, and the generation of dust.

Accordingly, the present invention was created in order to solve the limitations and problems of the prior art described above, and the conveying mixture for avoiding the dead zone of sludge by indirect heating drying method during sludge drying and conveying a part of the dry sludge to dry in multiple stages The drying efficiency was increased by mixing the sludge in the dryer with the cohesive clay and the foaming incinerator at 80 to 90% by weight, 5 to 15% by weight, and 1 to 5% by weight, respectively. It is possible to produce aggregates with high strength by processing and using the thermal energy from combustion of organic matter in sludge to drastically reduce the amount of auxiliary fuel used and removing irregular pores in the mixed sludge through the compression process after mixing. Through a ball molding machine to remove spherical pellets of constant size It aims to resource sewage and wastewater sludge into ultra-light aggregates with many micropores in an efficient and economic way.

In addition, the purpose is to provide ultra-light aggregates with a large number of micropores produced as raw materials such as auxiliary base material of civil engineering, environmental water treatment media, horticulture analysis, building sound insulation or fireproof materials.

BEST MODE Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a process diagram showing a system process for recycling sewage and wastewater sludge according to the present invention into ultra-light aggregates having a large number of micropores, and FIG. 2 is an installation state diagram showing a recycling system of sewage and wastewater sludge according to the present invention. 2a and 2b are side views, and 2c is a top view.

As shown in the accompanying drawings, the system for recycling the sewage and wastewater sludge according to the present invention into ultra-light aggregates having a large number of micropores includes a storage hopper 10 capable of storing and automatically transporting the sludge; A reservoir 14 for storing and supplying clay or incineration ash; A sludge dryer 20 configured to dry by mixing the sludge supplied from the storage hopper 10 and the clay and the incineration ash supplied from the storage tank; A first quantitative feeder 28 for supplying quantitatively the sludge dried in the dryer and clay and incineration ash; A mixer 40 for evenly mixing the dried sludge supplied from the first metering feeder 28 with clay and incineration ash; A second quantitative feeder (42) for quantitatively supplying sludge mixed from the mixer; A continuous kneader 44 for compressing the mixed sludge supplied from the second metering feeder 42; A refiner 46 for pelletizing the mixed sludge compressed from the continuous kneader 44; A ball molding machine 48 for giving a ball shape of a sphere to the pallet transferred from the refining machine 46; A surface dryer (50) for preliminarily drying the pellets transferred from the ball molding machine (48); It is composed of a rotary kiln 52 for sintering the pellets transferred from the surface dryer 50 to have a plurality of micropores.

In addition, a dust collector 30 for removing dust generated from the sludge dryer 20 and an exhaust gas dehumidification tower 32 for purifying malodors and harmful gases are separately installed, and high temperature exhaust gas from the rotary kiln 52 is provided. The waste heat boiler 60 and the air preheater 62 to cool the filter and the filter dust collector 70 and the wet scrubber 72 to purify and discharge the odor and harmful gases discharged from the air preheater.

This will be described in more detail as follows.

The sludge supply apparatus includes a storage hopper 10 for storing sewage and wastewater sludge, a transfer pump 12 for automatically transferring sludge to a dryer, a storage tank 14 for storing clay and incineration ash, and a sludge dryer for the clay and incineration ash. It is composed of a conveyor 16 for conveying up to (20).

The sludge dryer 20 mixes the sludge supplied from the storage hopper 10 with the clay and the incineration material supplied from the storage tank 14 to dry and transfer the dry sludge to the discharge conveyor 22 and the upward conveyor 24. It consists of a conveying conveyor (26) for re-injecting a part of the dry sludge back to the dryer (20).

The sludge dryer 20 has a plurality of disks therein, and includes a driving device for rotating the disk and advancing the sludge, a scraper for removing the sludge attached to the disk surface, and an inlet for steam, which is a heat source for drying. have. The disk rotation speed of the sludge dryer 20 is 6 to 10 RPM, the steam pressure is 7kg / ㎠G, the residence time is 20 to 30 minutes and the dryer internal pressure is preferably maintained at -10 to -20 mmAq. Do.

The clay and the incineration ash supplied from the storage tank 14 are introduced into the dryer 20 to adjust moisture, and are mixed with dry sludge firstly. At this time, the mixing ratio is preferably 80 to 90% by weight, 5 to 15% by weight of clay, 1 to 5% by weight of incineration ash. When the mixing ratio of the sludge is less than 80% by weight, when the amount of organic matter contained in the sludge is burned due to the low amount of combustion energy, the use of auxiliary fuel is increased, and a large number of micropores can be formed inside the pallet through self-heating. It is desirable to maintain the mixing ratio because no lightweight aggregate is produced.

Clay is a raw material that keeps the cohesiveness so that the sludge and the incineration material adheres well to each other, and the incineration ash is an auxiliary material for forming bubbles to make pores well because it has foamability. The clay is not particularly limited, but for example, Iksan and budget loess are used, and incineration ash is used as a material of pulp ash or fly ash that can form a plurality of fine pores during incineration.

The sludge dryer 20 uses steam as a heat source for drying the sludge, which is made in a waste heat recovery boiler 60 cooling the high-temperature exhaust gas discharged from the rotary kiln 52 and sent to a steam inlet. Steam is transferred into the disc inside the dryer to dry the sludge adhering to the disc surface. For this reason, it is called indirect heating method. As a method for avoiding sludge dead zones when drying sludge, the sludge is dried by indirect heating, and a part of the dried sludge is returned to the dryer 20 to recover water content in the sludge by using a multi-step drying method of 2-3 times. Lower it to 25-40%. In addition, by embedding a large number of disks having a large heat transfer area can be processed in large quantities by maximizing the thermal efficiency by indirect conduction, and is configured to increase the drying efficiency by maintaining the inside of the dryer in a vacuum to maximize the evaporation of water in the sludge.

On the other hand, the auxiliary boiler 80 for generating and supplying the insufficient steam heat source during the initial operation and the tank 82 for storing the refined fuel flow used to make the steam consists of an environmentally friendly system.

The odor and harmful gas generated during the sludge drying are the primary dust collector 30 and the wet dehumidification tower 32 for second purifying the purified noxious gas and the heat exchanger for exchanging hot water heated in the wet dehumidification tower ( 34) and cooling tower 36 to remove dust contained in exhaust gas, to remove odor and dehumidification through dehumidification, and to purify the odor by sending the purified gas to the rotary kiln 52 for combustion. It was.

20 to 30% by weight of the dry sludge and clay and the incineration ash which are not re-injected through the conveying conveyor among the dry sludge are supplied to the mixer 40 through the primary quantitative feeder 28 and homogeneously in the mixer 40. It is stirred. The primary metering feeder 28 is configured to push the sludge forward while the feed screw is rotated by the motor therein.

The mixer 40 receives a predetermined amount of dried sludge, clay and incineration ash, and has a wavy impeller configured therein to be mixed with the water supplied by the metering pump. The mixed sludge mixed in the mixer 40 is transferred to the secondary metering feeder 42 and stirred again to make the mixing sludge a constant mixing ratio. The secondary metering feeder 42 has the same configuration as the primary metering feeder 28, and supplies a constant amount of mixed sludge to the continuous kneader 44.

The continuous kneader 42 is configured such that a kneading screw is operated by a motor to remove pores therein by crushing the supplied mixed sludge, and the rotation speed is 10 to 20 RPM and the internal residence time is 1 to It is desirable to maintain 5 minutes, and if the residue dries inside, an appropriate amount of water supply is required in advance. The mixed sludge compressed in the continuous kneader 42 is supplied to the refining machine 46.

The refining machine 46 is composed of a built-in screw conveyor with a blade having a thick blade, it is preferable to maintain a rotational speed of 10 to 20 RPM, residence time 2 to 5 minutes. In the refining machine 46, the mixed sludge is made in the noodle state, and the mixed sludge in the noodle state is transferred to the ball forming machine 48.

The ball molding machine 48 has a cylindrical cylinder and a rotating body therein, and is configured such that the pellet in the noodle state is formed into a spherical shape while the rotating body is rotated by a motor, and the rotational speed is 200 to 400 RPM. It is preferable to hold time for 30 to 50 seconds. At this time, water can sometimes be supplied to achieve spheronization and dust removal. The ball molding machine 48 is configured as two to eliminate the bottleneck during pallet transfer, to produce a mixed sludge in a spherical shape to have a uniform strength to transfer the spherical pallet to the surface dryer 50 to be described later.

The surface dryer 50 is configured to dry the water content of 15 ~ 20% of the spherical pellets at an internal temperature of 80 ~ 120 ℃, the residence time is preferably maintained for 10 to 20 minutes. The heat source is configured to be supplied from an air preheater 62 connected to the rotary kiln 52. The spherical pellets discharged from the surface dryer 50 are transferred to the rotary kiln 52.

The rotary kiln 52 is composed of a motor and a kiln for rotating the kiln, and an inlet of a spherical pallet, a calcined pallet outlet, and a hot gas outlet, the rotational speed of 1 to 5 RPM, the slope of 1.9 degrees, and the inside It is preferable that the residence time is 10 to 30 minutes and the internal temperature of the kiln is 950 to 1300 ° C. In the rotary firing furnace 52, the inside of the pallet is foamed to form pores, and the outside is protected by a hard film by melting to make a pallet product having a desired hardness, and maintains uniformity of the product and minimizes product loss. It is configured to apply the method. That is, in the process of raw material pellets being put into product pallets, light oil and refined fuel oil, which are external heat sources, are injected into the inside through a burner to form a high temperature, and the pores are formed for a sufficient residence time while the pallet and the hot gas are in countercurrent. At this time, the firing furnace is configured to form an ultra-light aggregate having a large number of micropores by foaming is promoted by the internal heat of the sludge as the progress of the rotation.

The high-temperature exhaust gas discharged from the rotary kiln 52 is discharged through the waste heat boiler 60 and the air preheater 62, and the discharged harmful gas is filtered dust collector 70 and wet type for dust collection using a Teflon bag. The desulfurization oxide, denitrification oxide, dehydrogen chloride, dust collection, and the like are discharged as a clean gas while passing through the washing tower 72. In addition, by converting from the waste heat boiler to steam and sent to the sludge dryer 20 to achieve a waste heat recovery and eco-friendly system. At this time, the lime dust is added to the filter dust collector 70 to purify the noxious gas, and caustic soda is added to the wet scrubber 72 to collect harmful substances.

Embodiments of the present invention are as follows.

<Example 1>

Sewage sludge (heating amount: 3,000 to 3,400 kcal / kg · DS, ignition loss: 50 to 60% by weight) generated at the sewage terminal treatment plant in Jeonju-si, 90 kg (dry basis) After mixing 8 kg and 2 kg of paper sludge incinerator as a catalyst, the mixed sludge is transferred to a compression kneader to compress the mixed sludge to remove bubbles in the mixed sludge, which is passed through a refining machine to make a noodle state. Cut into a square of about 10 mm with a cutter, transfer it to a ball molding machine, shape it into a sphere of less than 6 mm in diameter, and dry it to 15-20% by weight of water in a surface dryer. This was calcined for about 30 minutes in a rotary kiln at an internal temperature of 1,200 ℃. Physical properties of the resulting fired body are shown in Table 1 below (the same applies)

<Example 2>

5 kg of clay was mixed with 90 kg of sewage sludge of Example 1, and 5 kg of paper sludge incineration ash was mixed with an initiator, and then calcined for 20 minutes at an internal temperature of 1150 ° C. in a kiln after surface drying and spherical molding as in Example 1.

division Apparent specific gravity (g / cm3) Example 1 0.5 ± 0.03 Example 2 0.55 ± 0.03 Natural stone lightweight aggregate 0.65 ± 0.05

 Comparison of ultra-light aggregate quality having a large number of micropores produced by the embodiment of the present invention is no product produced by using sewage sludge inevitably compared to Hortag natural stone lightweight aggregate of Lytag UK.

Comparing the apparent specific gravity with the imported natural light aggregate from England in Table 1, it can be seen that the aggregate produced in Examples 1 and 2 is lower than the imported natural light aggregate from England.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of the claims to be described below.

As described above, the sewage and wastewater sludge recycling system according to the present invention increases the drying efficiency by the conveying mixing method in which the sludge is avoided by the indirect heating drying method and the conveying part of the dry sludge is dried in a multi-step manner. While mixing the sludge in a drier with clay and foamable incineration ash at a ratio of 80 to 90% by weight, 5 to 15% by weight and 1 to 5% by weight, respectively, the water content in the sludge is effectively 25 to 25%. It is possible to produce ultra-light aggregate by lowering up to 40% and mixing it homogeneously in the mixer, and then removing irregular pores inside the mixed sludge through the compression process. Carbide with a large number of micropores in sewage and wastewater sludge in an efficient and economic way It can be used as raw materials for civil engineering, environment, horticulture and construction by producing high quality ultra-light aggregate with low specific gravity and high hardness thermal insulation effect. It is a useful invention.

1 is a process chart showing a process of a system for recycling sewage and wastewater sludge into ultralight aggregate according to the present invention.

FIG. 2 is an installation state diagram showing a system for recycling sewage and wastewater sludge into ultra-light aggregates according to the present invention, and FIGS. 2A and 2B are side views, and 2C is a plan view.

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

10: sludge storage hopper 12: sludge conveying pump

14: clay and incinerator reservoir 20: sludge dryer

22: discharge conveyor

24: upward conveyor 26: conveying conveyor

28: Primary Dosing Feeder

30: dust collector 32: exhaust gas dehumidification tower

34: heat exchanger 36: cooling tower

40: Mixer 42: Secondary Metering Feeder

44: continuous kneader 46: reinforcing machine

48: ball forming machine

50: surface dryer 52: rotary kiln

60: waste heat boiler 62: air preheater

70: filter dust collector 72: wet scrubber

80: auxiliary boiler 82: refining oil storage tank

Claims (8)

delete A storage hopper 10 capable of storing and automatically transporting sludge; A storage tank 14 for storing and supplying additional auxiliary materials; A sludge dryer 20 configured to dry the sludge supplied from the storage hopper 10; The sludge dryer 20 further includes a conveying conveyor 26 for recovering a part of the dried sludge and drying it in multiple stages, wherein the dried sludge supplied from the sludge dryer 20 is mixed with an additive adjuvant. Mixer 40; A continuous kneader 44 for compressing the homogeneously stirred mixed sludge from the mixer 40; A refiner 46 for pelletizing the mixed sludge compressed from the continuous kneader 44; A ball molding machine 48 for imparting a spherical ball shape to the pallet from the refining machine 46; A surface dryer (50) for preliminarily drying the spherical pellets formed in the ball molding machine (48); Rotary kiln 52 for sintering the pellets from the surface dryer (50); Odor and harmful gas generated from the filter dust collector 70 and the dryer 20 to purify the odor and harmful gases from the rotary kiln 52 and the dust collector 30 and the wet dehumidification tower (the primary dust collector) ( In the sludge aggregate manufacturing system installed to be treated in (32), The sludge dryer 20 includes a plurality of disks, a drive device for rotating the disk and the sludge, and a steam inlet for drying, and the steam cools the high-temperature exhaust gas discharged from the rotary kiln 52. The waste water recovery boiler 60 is made of a facility system for recycling the sewage and wastewater sludge into ultra-light aggregates, which is characterized in that it is sent to the inside of the disk of the dryer (20). The method of claim 2, In the sludge dryer 20, sludge, clay, and incineration materials are mixed at 80 to 90% by weight, 5 to 15% by weight, and 1 to 5% by weight, respectively. Equipment system. The method of claim 2, The continuous kneader 42 is configured such that a kneading screw is operated by a motor to remove pores therein by crushing the supplied mixed sludge, and the rotation speed is 10 to 20 RPM and the internal residence time is 1 to Facility system for recycling sewage and wastewater sludge to ultra-light aggregates, which is configured to hold 5 minutes. The method of claim 2, The refining machine 46 is composed of a screw conveyor with a blade having a thick blade is built, and the ultra-light aggregate of sewage and wastewater sludge, characterized in that it is configured to maintain a rotational speed of 10 to 20 RPM, residence time 2 to 5 minutes Equipment system to be recycled. The method of claim 2, The ball molding machine 48 is provided with two, each of which is provided with a cylindrical cylinder and a rotating body driven by a motor to form a pellet in a noodle state to be spherical shape, the rotational speed is 200 ~ 400 RPM A facility system for recycling sewage and wastewater sludge to ultra-light aggregates, wherein the wastewater sludge is configured to be held for 30 to 60 seconds. delete The method of claim 2, The system for recycling the sewage and wastewater sludge to ultra-light aggregates, characterized in that configured to send the gas purified by the wet dehumidification tower (32) to the rotary kiln (52) for combustion.