JP2018001127A - Carbonization treatment facility of sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbonization treatment facility of sludge hardly generating clog even when an oil component is contained in a dust generated during a dry treatment of the sludge, capable of conducting dust collection at high efficiency and achieving load reduction of maintenance works.SOLUTION: There is provided a carbonization treatment facility 1 of sludge having (a) a dryer 16 for dryness treatment of organic material-containing sludge to a prescribed moisture state, (b) a hot wind generation furnace 50 for generating hot wind for drying in the dryer 16 and (c) a circulation pathway 51 for supplying hot wind generated in the hot wind generation furnace 50 to the dryer 16 and returning exhaust gas discharged from the dryer 16 to the hot wind generation furnace 50. A dust collection machine 52 arranged on the circulation pathway 51 has a filter through which exhaust gas introduced inside of the dust collection machine 52 passes when moving to an exhaust port 75 of the dust collection machine 52, is constituted by a filter by laminating a plurality of meshed metal sheets having a plurality of through holes bored in same inclined direction as a sheet surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to sludge carbonization equipment, and more particularly, to sludge carbonization equipment equipped with a dust collector that collects dust generated during sludge drying.

Wastewater containing organic matter discharged from homes and the like is generally treated with sewage treatment equipment.
Organic sludge is generated along with this wastewater treatment, but the amount of organic sludge generated increases year by year as the amount of wastewater treatment increases, and its treatment and disposal become a major problem.

When disposing of organic sludge, organic sludge contains about 99.9% of water and cannot be disposed as it is, where it can be concentrated and dehydrated for weight reduction, or further incinerated or melted. Various processes are currently being performed.
However, if sludge is incinerated or melted, a large amount of energy is consumed, resulting in high processing costs.

Therefore, as one method for reducing the amount of organic sludge that consumes less energy, it has been proposed to carbonize the sludge by dry distillation.
In this carbonization treatment, the sludge contains about 45% by mass of carbon in the substrate. Therefore, the carbon content in the sludge is not consumed like incineration and melting treatment, but the sludge is oxygen-free or low. By pyrolysis (carbonization) in an oxygen state, the carbon content remains, and is produced as a carbide (carbonized product) having a new composition.

  When carbonizing sludge by dry distillation treatment, dehydrated sludge (water-containing sludge) dehydrated to a water content of about 80% is first dried to a predetermined water content, for example, a water content of about 40%, and the water content is reduced. Thereafter, the dried sludge that has been dried is conveyed to a carbonization furnace where the sludge is carbonized by dry distillation. Carbonization equipment used for such treatment is disclosed in, for example, Patent Literature 1 and Patent Literature 2 below.

  By the way, in this carbonization equipment, in the process until the dewatered sludge is exposed to the hot air for drying and dried to become the dried sludge, a part of it becomes dust and flows into the exhaust gas passage, and the circulation fan in the subsequent stage As a result, the exhaust gas (hot air) that has passed through the dryer passes through the dust collector, where the dust in the exhaust gas is separated and removed.

As a dust collector, a bag filter with a high dust removal efficiency of 90% or more is generally used. However, the nature of organic sludge generated in sewage treatment facilities varies depending on the region, and the sludge contains a large amount of oil. In this case, the filter cloth of the bug filter is clogged at an early stage and cannot be used continuously. In such a case, conventionally, a cyclone capable of continuously removing dust even when dust containing oil is used, although the dust removal efficiency is inferior to that of the bag filter.
However, since the dust removal efficiency of the cyclone is about 70%, the proportion of dust that has moved to the latter stage of the dust collector has increased, and the frequency of maintenance has increased due to the dust adhering to the latter stage equipment. For example, if dust adheres to the impeller of the circulation fan, the vibration of the fan increases, so the impeller must be removed and cleaned. Such an increase in maintenance work is not only a burden on the workers, but also during that time, the equipment is stopped and the equipment operation rate is reduced.

Japanese Patent Laid-Open No. 11-33599 JP-A-11-37644

  The present invention is based on the above circumstances, and even when oil is contained in the dust generated during the sludge drying process, clogging is unlikely to occur, and dust can be collected efficiently, and maintenance work can be performed. The object of the present invention is to provide a sludge carbonization facility capable of reducing the load.

  Thus, the present invention provides (a) a dryer for drying the organic substance-containing sludge to a predetermined moisture state, (b) a hot air generating furnace for generating hot air for drying in the dryer, and (c) the hot air A circulation path for supplying hot air generated in a generator to the dryer and returning exhaust gas discharged from the dryer to the hot air generator, and a carbonization treatment facility for sludge, on the circulation path Is provided with a dust collector for separating and removing dust in the exhaust gas, and the dust collector has the same filter as the plate surface through which the exhaust gas introduced into the dust collector passes when it goes to the discharge port of the dust collector. It is characterized by comprising a filter in which a plurality of mesh-like metal plates provided with a plurality of through holes drilled in an inclined direction are laminated.

  According to a second aspect of the present invention, in the first aspect, the dust collector has a baffle plate provided to face an inlet for introducing the exhaust gas into the dust collector, and the filter is provided on the baffle plate. It is characterized by.

  According to a third aspect of the present invention, in any one of the first and second aspects, the dust collector is provided with a spraying means for spraying water toward the exhaust gas flowing through the dust collector and the filter. And

  According to a fourth aspect of the present invention, in the third aspect, the treated water purified by the sewage treatment facility is supplied to the spraying means, and the treated water discharged from the dust collector is returned to the sewage treatment facility. It is characterized by that.

  As described above, the present invention is provided with a plurality of through holes formed in the same inclined direction with respect to the plate surface of the filter of the dust collector for separating and removing dust in the exhaust gas discharged from the dryer for drying sludge. In addition, the filter is formed by a filter in which a plurality of mesh-like metal plates are stacked. In the present invention, dust in the exhaust gas is collected in the filter according to the principle of inertial dust removal and collision separation, so dust can be collected even if the size of the through-hole through which the exhaust gas passes is sufficiently larger than that of the bag filter. Thus, it is possible to prevent early clogging due to dust containing oil.

  In the present invention, a baffle plate can be provided facing the inlet for introducing exhaust gas into the dust collector, and the filter can be provided on the baffle plate. The baffle plate is effective for separating and removing a part of the dust in the exhaust gas by colliding the exhaust gas introduced inside. Further, according to the second aspect, by providing the filter on the baffle plate, a dedicated member for attaching and supporting the filter can be made unnecessary, and the structure inside the dust collector can be simplified.

In the present invention, spray means for spraying water toward the exhaust gas and the filter that circulates inside the dust collector can be provided inside the dust collector (claim 3).
According to the third aspect, when the dust in the exhaust gas comes into contact with the sprayed water droplets, they are adsorbed and removed by the water droplets. Also, dust collected in the filter when passing through the filter is adsorbed by the water droplets and discharged together with the water droplets. For this reason, the filter can be washed well.

The exhaust gas introduced into the dust collector is a high-temperature gas of about 180 ° C. containing water vapor, but when cooled to below the dew point by water spray, the water vapor contained in the exhaust gas becomes water, and the outside of the system To be discharged.
In the carbonization treatment facility of the present invention, the amount of exhaust gas flowing through the circulation path can be reduced by performing the water spray. Accordingly, the waste heat released to the outside through the chimney is reduced, so that the amount of fuel used in the hot air generating furnace can be reduced, and the operating cost can be reduced.

Here, as the water used for the spraying means, the treated water purified by the sewage treatment facility can be supplied, and the treated water discharged from the dust collector can be returned to the sewage treatment facility (Claim 4). .
During sewage treatment, sludge is generated, while a large amount of sewage sewage is purified, and the purified treated water is discharged into rivers, lakes, or the sea. In this example, the operation cost can be reduced by using a part of the treated water discharged in large quantities as the supply water for the spraying means.

  According to the present invention as described above, even when the dust generated during the sludge drying process contains oil, clogging is unlikely to occur in the dust collector, and dust collection can be performed efficiently. It is possible to provide a sludge carbonization facility capable of reducing the load.

It is the figure which showed the whole structure of the carbonization processing equipment of the sludge of one Embodiment of this invention. It is the figure which showed the structure of the dryer in FIG. It is the figure which showed the structure of the carbonization furnace in FIG. It is the figure which showed the structure of the dust collector in FIG. It is the figure which showed the structure of the filter of FIG. 4 typically. It is the figure which showed the flow of the sewage treatment equipment, and the water supply / drainage path | route used by the dust collector.

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an overall configuration of a sludge carbonization treatment facility 1 according to an embodiment of the present invention. In the carbonization treatment facility 1, a large amount of organic sludge generated along with the wastewater treatment is continuously treated to produce a carbonized product.
In the figure, reference numeral 10 denotes a receiving hopper (dehydrated sludge storage tank). Dehydrated sludge obtained by dewatering sewage sludge containing organic matter to a moisture content of about 70 to 85% (usually about 80%) is first received by the receiving hopper 10. It is done.
The dewatered sludge accepted here is sent to the dryer 16 through the intermediate storage tank 12 by the fixed supply device 14 and the transport device 15, where the moisture content is about 35 to 45% (usually about 40%). Is done.

  The dryer 16 has a stirring shaft 20 inside the rotary drum 18 as shown in FIG. Here, the stirring shaft 20 is provided at a position eccentric from the center of the rotary drum 18. A plurality of stirring blades 22 extend radially from the stirring shaft 20.

On the other hand, a plurality of plate-like lifters 24 are provided on the inner peripheral surface of the rotary drum 18 at a predetermined interval in the circumferential direction so as to rotate integrally with the rotary drum 18.
As a result, the sludge (dehydrated sludge) inside the rotary drum 18 is lifted upward from the bottom by the lifter 24 as the rotary drum 18 rotates, and falls by its own weight near the top. The sludge that has fallen is finely pulverized by the high-speed rotation of the stirring blade 22 located on the lower side, and falls to the bottom side of the rotary drum 18.

The sludge inside the rotary drum 18 is subjected to such a stirring action, is exposed to the hot air for drying introduced into the rotary drum 18 and is dried, and the moisture gradually decreases. At this time, the water contained in the sludge becomes water vapor and moves to the exhaust gas side.
In the dryer 16, sludge is gradually sent in the axial direction inside the rotary drum 18 by the pulverization by the stirring blade 22 and the scattering action at that time.

  The dried sludge that has been dried in the dryer 16 in this way is then conveyed by the conveying device 26 to the carbonizing furnace 32 via the carbonizing furnace charging device 28, where the sludge is carbonized by dry distillation.

  This carbonization furnace 32 is a furnace that dehydrates and pyrolyzes dry sludge in an oxygen-free or low-oxygen atmosphere, and as shown in FIG. ) 36 is provided, and the dried sludge dried by the preceding dryer 16 is put into the rotary drum 36.

  The supplied dried sludge is first heated by the atmosphere heating inside the external heat chamber 40 by the auxiliary combustion burner (burner for external heat chamber) 38 disposed inside the furnace body 34. Then, the combustible gas contained in the dried sludge escapes into the atmosphere of the external heat chamber 40 through the ejection pipe 42 provided in the rotary drum 36, and this combustible gas is ignited. Thereafter, the combustible gas is burned. Thus, the sludge inside the rotary drum 36 is heated. At this stage, the auxiliary burner 38 is stopped from burning.

  As shown in FIG. 3, an exhaust gas treatment chamber 44 separated from the external heat chamber 40 is provided inside the furnace body 34, and the exhaust gas from the external heat chamber 40 is guided here. The exhaust gas treatment chamber 44 is provided with an exhaust gas treatment chamber burner 46, and unburned gas in the exhaust gas introduced into the exhaust gas treatment chamber 44 is subjected to secondary combustion in the exhaust gas treatment chamber burner 46. .

  The sludge in the rotary drum 36 gradually moves to the right in the figure from the left end in the figure along with the rotation of the rotary drum 36 (the rotary drum 36 has a slight gradient), and finally the carbonization residue (carbonization residue) Product) is discharged from the right end outlet 48 of the rotary drum 36, that is, from the carbonization furnace 32. By such a carbonization operation, the dried sludge is converted to a carbonized product having pores, which is composed of about 30 to 50% of carbon and the rest of which is inorganic.

  Then, since the carbonized product that has been completely carbonized and discharged from the carbonization furnace 32 is heated to a high temperature, as shown in FIG. It is conveyed upward by the conveyor 71. In order to suppress self-heating, humidification (water spraying) for adjusting the amount of water is performed in the humidifier 100, and then the carbonized product is stored in the carbonized product storage hopper 102.

  In FIG. 1, reference numeral 50 denotes a hot air generating furnace which is supplied with heavy oil for heating burner and combustion air and heats the gas to a predetermined temperature to generate hot air for drying. The hot air generated here is supplied to the dryer 16. The hot air supplied to the dryer 16 is discharged from the dryer 16 after being used for sludge drying treatment. Thereafter, the gas passes through a dust collector 52 provided on the hot air circulation path 51, and is further circulated by the circulation fan 54 to the hot air generator 50 through the carbonization furnace exhaust gas heat exchanger 56 and the hot air furnace exhaust gas heat exchanger 58. The circulation fan 54 is configured such that the fan motor that drives the fan includes an inverter, and the fan rotation speed can be changed by inverter control. The circulation fan 54 circulates in the hot air circulation path 51 by changing the fan rotation speed. The gas (hot air) flow rate can be adjusted.

In this circulation system, leak air enters the hot air circulating in the dryer 16.
On the other hand, a constant amount of combustion air is supplied to the hot air generating furnace 50, and therefore, a part of the hot air is extracted here through the branch path 60 extending from the hot air generating furnace 50, and the hot air passes through the hot air furnace exhaust gas heat exchanger 58. It is discharged from the chimney 64 by the furnace exhaust gas fan 62. That is, a part of the exhaust gas discharged from the dryer 16 is burned and deodorized in the hot air generating furnace 50 and then released to the outside through the chimney 64.
On the other hand, an exhaust passage 66 extends from the carbonization furnace 32, and exhaust gas from the carbonization furnace 32 is discharged from the chimney 64 through the carbonization furnace exhaust gas heat exchanger 56 through the exhaust passage 66 through the carbonization furnace exhaust gas heat exchanger 56. The

FIG. 4 shows the internal structure of the dust collector 52 provided in the subsequent stage of the dryer 16. In addition, about the internal structure of the dust collector 52 described below, a design change is possible suitably using a well-known technique.
In the figure, reference numeral 72 denotes a vertically long rectangular casing, which is provided with an introduction port 74 for introducing hot air (exhaust gas of the dryer 16) into the inside and a hot air discharge port 75 at the upper side. A hopper 73 is integrally provided below the casing 72. A discharge valve 77 for discharging dust is attached to the lower part of the hopper 73.

  A baffle plate 76 whose periphery is bent toward the side wall (72a) of the casing 72 is vertically attached to the inside of the casing 72 and in the vicinity of the introduction port 74 so as to face the introduction port 74. The interior is partitioned into a front chamber 79 and a dust collection chamber 80. The exhaust gas introduced into the front chamber 79 from the introduction port 74 collides with the baffle plate 76 to adjust the flow.

A filter 78a is attached to the main surface portion of the baffle plate 76 that is substantially parallel to the side wall 72a of the casing 72 in two vertical directions, and most of the exhaust gas introduced into the front chamber 79 is the filter 78a. And flows into the dust collecting chamber 80. At this time, a part of the dust in the exhaust gas is separated and removed by the filter 78a. FIG. 4C illustrates the filter 78a located below in the plan view among the filters 78a attached in two places in the vertical direction. As shown in the figure, a filter 78a is attached over substantially the entire width in the width direction of the main surface portion of the baffle plate 76 that is substantially parallel to the side wall 72a.
In addition, a gap is provided between the side wall 72a on the side and the lower side of the baffle plate 76 attached to face the side wall 72a, and a part of the exhaust gas flows into the dust collecting chamber 80 through the gap. . A part of the dust colliding with the baffle plate 76 falls into the hopper 73 through this gap.

  The exhaust gas flowing into the dust collection chamber 80 then flows upward toward the upper discharge port 75. A plurality of filters 78b connected in the horizontal direction orthogonal to the traveling direction of the exhaust gas are installed on the flow path, and the exhaust gas is allowed to pass through the filter 78b, whereby dust is separated and removed. The filters 78a and 78b have the same configuration, and are referred to as the filter 78 when collectively referred to.

  FIG. 4B is a plan view of the filter 78b. A shielding plate 82 is provided around the filter 78b to prevent the exhaust gas from flowing. The exhaust gas flowing upward is always filtered. It is configured to pass through 78b. Reference numeral 85 denotes a frame that supports the filter 78b.

Reference numeral 83 denotes a water supply pipe provided through the side wall of the casing 72 inward and outward, and a plurality of nozzles 84 are attached to the tip thereof. The water guided to the dust collection chamber 80 by the water supply pipe 83 is sprayed downward from the nozzle 84 or laterally toward the filter 78a. In this example, the water supply pipe 83 and the nozzle 84 constitute the spraying means.
According to this example, when the dust in the exhaust gas comes into contact with the sprayed water droplets, they are adsorbed and removed by the water droplets. Also, dust collected by the filters 78 a and 78 b when passing through the filters 78 a and 78 b is also adsorbed by the water droplets, and these water droplets and dust fall into the hopper 73.

The exhaust gas (hot air) introduced into the dust collection chamber 80 is a high-temperature gas of about 180 ° C. including water vapor generated in the dryer 16. When this exhaust gas is cooled below the dew point by water spray from the nozzle 84, the water vapor contained in the exhaust gas becomes water and is discharged to the outside from the lower discharge valve 77. Thus, the exhaust gas is discharged from the discharge port 75 in a dry gas state in which the total amount is reduced and the water vapor concentration is reduced.
A demister 86 is provided above the dust collection chamber 80 and in the vicinity of the discharge port 75. Mist in the exhaust gas comes into contact with the demister 86 and is removed.

  FIG. 5 is a diagram showing the configuration of the filter 78. This filter 78 is formed by laminating a plurality of stainless steel metal plates 88 having a plurality of through holes formed in a mesh shape in the thickness direction, and each of the metal plates 88 has a plurality of through holes 90. It is perforated in the same inclination direction with respect to the surface (in a state inclined by an angle α in FIG. 5B). When the plurality of metal plates 88 are laminated, the inclination angles of the through holes 90 are sequentially shifted by 90 ° in the plane direction between the adjacent metal plates 88.

For this reason, whenever it passes through these through-holes 90, the exhaust gas collides with the metal plate 88 forming the through-holes 90, and the direction of the flow is changed to the inclined direction of the through-holes 90. The collected dust is collected in the filter 78 by the principle of inertial dust removal and collision separation. Since each through-hole 90 is sufficiently larger than the bag filter, clogging does not occur at an early stage even with dust containing oil. The number of metal plates 88 stacked in the plate thickness direction can be changed as appropriate in accordance with the target dust removal efficiency.
For example, a commercially available pyro screen (manufactured by Nunobiki Seisakusho Co., Ltd.) can be used as the filter configured as described above.

  FIG. 6 is a diagram showing a flow of the sewage treatment facility. In the figure, the raw water of the sewage is separated from the first settling sludge in the first settling basin 93 after large dust is removed in the settling basin 92. Next, the supernatant water of the first sedimentation basin 93 flows into the aeration tank 94 and is subjected to aerobic treatment by aeration. Next, the liquid in the aeration tank 94 is introduced into the final sedimentation basin 95 and separated into sedimentation sludge and supernatant water, and the supernatant water is subjected to pH adjustment 96 and then discharged into the river and the sea as treated water.

  On the other hand, the sludge separated in each pond or tank is sent to the sludge concentration tank 97 and concentrated, and then the water is removed by the dehydrator 98. The sludge dehydrated to a water content of about 80% is fed into the carbonization equipment 1 as a dehydrated cake (dehydrated sludge).

In such a sewage treatment facility, a large amount of purified treated water, for example, 10,000 m ³ / day is generated. In this example, a part of this treated water is transferred to the casing 72 of the dust collector 52 by the transport pump 99 and the water supply pipe 83. Supply inside. Then, the treated water sprayed with water in the dust collector 52 flows through the dust collecting chamber 80 and is discharged from the discharge valve 77, and then returned to the sand basin 92 through the drain pipe 104.

  As described above, in the present embodiment, the filter 78 of the dust collector 52 is configured by a filter in which a plurality of mesh-like metal plates 88 each having a plurality of through holes 90 drilled in the same inclination direction with respect to the plate surface are stacked. According to this embodiment, the dust in the exhaust gas is collected in the filter 78 by the principle of inertia dust removal and collision separation, so the size of the through hole 90 through which the exhaust gas passes is larger than that of the bag filter. Even if it is sufficiently large, dust can be collected, and early clogging due to dust containing oil can be prevented.

  In this embodiment, since the filter 78a is provided on the baffle plate 76 provided to face the introduction port 74 of the dust collector 52, a dedicated part for attaching and supporting the filter 78a can be made unnecessary, and the inside of the dust collector 52 The structure can be simplified.

  In the present embodiment, the dust collector 52 is provided with a water supply pipe 83 and a nozzle 84 as spraying means for spraying water toward the exhaust gas and the filters 78a and 78b flowing through the dust collector 52, and dust in the exhaust gas is sprayed. When it comes into contact with the formed water droplet, it is adsorbed and removed by the water droplet. When passing through the filters 78a and 78b, the dust collected in the filters 78a and 78b is also adsorbed by the water droplets and discharged together with the water droplets. Therefore, the filters 78a and 78b can be cleaned well.

The exhaust gas introduced into the dust collector 52 is a high-temperature gas of about 180 ° C. containing water vapor, but when cooled to below the dew point by water spray, the water vapor contained in the exhaust gas becomes water, and the outside of the system It is possible to reduce the amount of exhaust gas discharged to the hot air circulation path 51.
In the carbonization treatment facility 1 of the present embodiment, the exhaust gas (hot air) discharged from the dryer 16 is returned to the hot air generating furnace 50 for combustion deodorization. A part of the exhaust gas heated (combusted and deodorized) in the hot air generating furnace 50 is supplied to the dryer 16 as hot air gas for drying, while the remaining exhaust gas is discharged to the outside through the chimney 64. In the present embodiment, as the amount of exhaust gas flowing through the hot air circulation path 51 decreases, the amount of fuel used in the hot air generator 50 can be reduced by reducing waste heat released to the outside through the chimney 64, The operating cost can be reduced.

  In the present embodiment, the treated water purified by the sewage treatment facility is supplied as water used for water spraying, and the treated water discharged from the dust collector 52 is returned to the sewage treatment facility. Thus, in this example, the operation cost can be reduced by using a part of the treated water discharged in a large amount during the sewage treatment as the supply water for water spray.

  Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the present invention, water spraying is performed in the dust collection chamber, but in some cases, it is also possible to perform dry dust collection without water spraying (in this case, the collected dust is removed. The present invention can be implemented in variously modified forms within a range not departing from the gist of the present invention. For example, the filters 78a and 78b must be provided with a vibration device for dropping and collecting them.

1 Carbonization equipment 16 Dryer 50 Hot air generator 51 Hot air circulation path (circulation path)
52 Dust collector 74 Inlet port 75 Outlet port 76 Baffle plate 78, 78a, 78b Filter 83 Water supply pipe (spraying means)
84 nozzle (spraying means)
88 Metal plate 90 Through hole

Claims (4)

(A) a dryer for drying the organic substance-containing sludge to a predetermined moisture state;
(B) a hot air generating furnace for generating hot air for drying in the dryer;
(C) a circulation path for supplying hot air generated in the hot air generator to the dryer and returning exhaust gas discharged from the dryer to the hot air generator;
A sludge carbonization facility equipped with a dust collector for separating and removing dust in the exhaust gas on the circulation path,
The dust collector has a mesh-like shape having a plurality of through holes formed in the same inclination direction with respect to a plate surface through a filter through which exhaust gas introduced into the dust collector passes toward the discharge port of the dust collector. A sludge carbonization facility comprising a filter in which a plurality of metal plates are laminated.   The said dust collector has a baffle board provided facing the inlet which introduces the said waste gas into the inside of the said dust collector, The said filter is provided in this baffle board. Sludge carbonization equipment.   The sludge carbonization treatment according to claim 1, wherein spraying means for spraying water toward the exhaust gas and the filter that circulates in the dust collector is provided inside the dust collector. Facility.   The treated water purified by a sewage treatment facility is supplied to the spraying means, and the treated water discharged from the dust collector is returned to the sewage treatment facility. Sludge carbonization equipment.

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