JP3891789B2 - Granulator dryer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a granulation dryer, and relates to a technique for drying sludges such as general raw materials, sewage sludge, industrial wastewater sludge and the like.
[0002]
[Prior art]
Conventionally, there are various types of general dryers, such as sewage sludge, industrial wastewater sludge and other sludge dryers, disk type dryers that dry sludge by indirect heat transfer by steam, ribbon type vacuum There are indirect steam heating methods such as dryers and centrifugal thin film dryers, and hot air direct heating methods such as sentry flashes and kiln dryers that dry sludge by direct heat transfer with hot air.
[0003]
For example, a kiln dryer supplies hot air and sludge dehydrated cake into the drum from one end of the inclined rotating drum, and moves the sludge into the drum while transferring the sludge to the other end of the drum by the inclined gradient and rotational movement of the drum. The sludge is dried by the hot air that is ventilated, and the dewatered cake is stirred and crushed by the scraping blades and the pulverizing blades arranged inside the drum to make contact with the hot air.
[0004]
[Problems to be solved by the invention]
However, in a rotary dryer such as a kiln dryer, the contact efficiency between the sludge (dehydrated cake) and the carrier gas (hot air) cannot be sufficiently increased only by stirring with a scraping plate. In order to lengthen the time, it is necessary to increase the diameter and axial length of the drum, and the entire dryer becomes larger due to the increase in drum volume. Further, it is necessary to dispose a heat insulating material such as a caster on the drum in order to prevent the outer surface of the drum through which hot air is ventilated from being heated, resulting in an increase in weight.
[0005]
The present invention solves the above-mentioned problems, and can increase the contact efficiency between the granulated product to be dried and the carrier gas without increasing the volume, and does not require a heat insulating material. The purpose is to provide a dryer.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the granulating dryer according to the first aspect of the present invention includes a plurality of tubular cylinders arranged concentrically to form a main body cylinder, and a granulated product to be dried at one end of the main body cylinder. And a carrier gas inlet of the heat source, and a dry granule and a carrier gas outlet connected to the other end, and a flow path is formed in multiple layers by dividing each tubular cylinder in the body cylinder. The flow paths are alternately connected at communication ports formed on one end side or the other end side of each tubular cylinder to form each layer flow path in a single system flow path, and a continuous screw is arranged on the inner surface of each tubular cylinder to provide each laminar flow. The innermost layer is formed inside the innermost tubular cylinder by forming the path spirally and forming a continuous screw arranged on the inner surface of each tubular cylinder in a spiral shape for transferring the granulated material to the upstream side of each layer flow path. Surrounded by a spiral channel and a continuous screw that form the channel with a continuous screw Formed in a linear flow path, connecting the inlet port to the innermost layer channel, constituted by connecting the outlet to the outermost flow path, granules of the downstream side of the flow path by the carrier gas While repeatedly moving and moving upstream by a continuous screw, fluidized drying and airflow drying are repeated while flowing downstream .
[0007]
With the above-described configuration, the granulated material and the carrier gas are supplied from the introduction port to the innermost layer flow path of the main body cylinder in a state where the main body cylinder is rotationally driven around the axis. Part of the carrier gas that flows in the vicinity of the inner peripheral surface of the tubular cylinder hits the continuous screw to become a turbulent flow, or a swirling flow along the continuous screw to cause the granulated material that stays in the lower part of the tubular cylinder to rise, causing a solid-gas mixed phase. The granulated product is fluidized and dried while forming a fluidized bed.
[0008]
The carrier gas flowing through the straight flow path is air-dried while conveying the granulated material soared downstream. The granulated material transported by the carrier gas gradually falls and lands on the tubular body, and is returned to the upstream side of the flow path by the continuous screw.
[0009]
In this way, the granulated material flows through the innermost flow path to the downstream side of the other end of the main body while repeatedly moving the flow path downstream by the carrier gas and moving upstream by the continuous screw. In addition, since it stays in the machine for a long time while repeating fluidized drying and airflow drying, the drying efficiency of the granulated product is increased.
[0010]
The granulated material that has reached the other end of the main body cylinder flows into the adjacent outer flow path through the communication port together with the carrier gas. In this flow path, the granulated material that receives the upstream transport action by the continuous screw and the downstream transport action by the carrier gas passes through the spiral flow path partitioned by the upper and lower tubular cylinders and the continuous screw. It moves to the downstream side while forming a fluidized bed of solid-gas mixed phase and realizes both actions of fluidized bed drying and airflow drying, so the contact efficiency and drying efficiency of carrier gas and granulated product become very high .
[0011]
Thereafter, the granulated material and the carrier gas sequentially flow into the outer channel, and are dried by fluidized bed drying and airflow drying while flowing in the direction opposite to the flow of the lower layer channel, and the outermost layer channel. Flows out of the body through the discharge port.
[0012]
Therefore, by increasing the retention time of the granulated material in the machine by the upstream conveying action by the continuous screw and realizing high contact efficiency and drying efficiency by both the fluidized bed drying and the airflow drying, To reduce the size of the dryer. Also, in the main body cylinder, the granulated product is transported to the downstream side only by the transport action by the carrier gas in a state in which the granulated product is transported to the upstream side by the continuous screw. Since sludge having low properties is not discharged outside the machine until the weight is reduced by sufficient drying, the weight and particle size of the dried granulated product are almost equal.
[0013]
Since the main body has a multi-layered flow path, the structure itself has heat insulation, and the carrier gas that flows from the innermost flow path to the outer flow path and flows out of the outermost flow path is granulated. Since the heat is deprived by heating the object and the temperature gradually decreases, the temperature in the outermost tubular body becomes lower, eliminating the need to install heat insulating materials such as casters as in the past, and reducing the weight of the device Can be planned.
[0014]
The granulation dryer of the present invention according to claim 2 is one in which linear fried plates along the axial direction are arranged at a plurality of locations on the inner surface of the innermost tubular cylinder.
With the configuration described above, the granulated material in which the scraping plate stays in the lower part of the tubular body is lifted and stirred to promote the formation of a fluidized bed by the carrier gas, and the contact efficiency and the drying efficiency can be improved.
[0015]
The granulation dryer of the present invention according to claim 3 is formed by only a spiral flow path in which an inner cylinder is inserted into an innermost tubular cylinder and an innermost flow path is formed by a continuous screw. .
[0016]
With the configuration described above, the entire flow path in the main body becomes a spiral flow path, and the granulated material forms a fluidized layer of solid-gas mixed phase with the carrier gas, realizing both fluidized bed drying and airflow drying. While moving downstream.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Although the granulation dryer according to the present invention can be used as a dryer for general raw materials, the present embodiment will describe a case where sludge such as sewage sludge and industrial wastewater sludge is dried.
[0018]
In FIG. 1, a dehydrated cake (water content 35% to 85%) 1 is supplied to a mixer 3 by a cake charging pump 2 and mixed with a return product of a dry granulated sludge described later in a mixer 3 to form a granulated sludge ( Granulated to a moisture content of 35% to 50%) 4 and then put into the dryer 5.
[0019]
The operation and structure of the dryer 5 will be described in detail later. A circulation gas 6 is supplied to the dryer 5 as a carrier gas (heating medium) together with the granulated sludge 4. The circulating gas 6 is heated by the heat exchanger 9 using the exhaust gas 8 generated in the hot stove 7 as a heating medium. The exhaust gas discharged from the heat exchanger 9 is discharged from the chimney 11 to the atmosphere through the exhaust gas system 10. The circulating gas 6 containing the dried granulated sludge 12 dried in the dryer 5 is supplied to the cyclone 13 and separated into solid and gas, and the circulating gas 6 is returned to the heat exchanger 9 by the circulating fan 15 via the dehumidifier 14, The gas is supplied to the hot stove 7 by the extraction fan 16.
[0020]
The dried granulated sludge 12 collected by the cyclone 13 is supplied to the classifier 17 and classified, and the medium-sized dried granulated sludge 12 having an appropriate particle size is conveyed to the bunker 19 by the conveyor 18 and conveyed from the bunker 19. The truck 20 is loaded.
[0021]
The large-sized dry granulated sludge 12 having an inappropriate particle size is crushed to an appropriate particle size by a crusher 21 and then supplied to the hopper 22. The small-sized dry granulated sludge 12 is directly supplied to the hopper 22, The product is supplied from the hopper 22 to the mixer 3 by the return conveyor 23 as a returned product.
[0022]
As shown in FIG. 2, in the dryer 5, the main body cylinder 31 has an inner-layer tubular cylinder 32, an intermediate-layer tubular cylinder 33, and an outer-layer tubular cylinder 34 arranged concentrically. The sludge 4 and the introduction port 35 for the circulation gas (carrier gas) 6 of the heat source are connected, and the other end is connected to the discharge port 36 for the dry granulated sludge 12 and the circulation gas 6. Is connected to a fixed pipe (not shown) through a sealant or the like, and a drive device (not shown) is provided that meshes with a gear 31a provided at one end of the main body 31.
[0023]
The main body cylinder 31 is internally partitioned by tubular cylinders 32, 33, and 34 to form an inner layer flow path 37, an intermediate layer flow path 38, and an outer layer flow path 39 in a multilayer shape. The intermediate layer channel 38 and the outer layer channel 39 are connected by a communication port 41 formed on one end side of the middle layer tubular body 33, and the respective layer channels are connected to each other. It is formed in the flow path of the system.
[0024]
Continuous screws 42, 43, 44 are arranged on the inner surfaces of the tubular cylinders 32, 33, 34 to form the respective layer flow paths 37, 38, 39 in a spiral shape. It is formed in a spiral shape for transferring the granulated sludge 4 to the upstream side of the flow paths 37, 38, 39. That is, as shown in FIG. 4, the continuous screw 42 arranged in the inner layer flow path 37 and the continuous screw 44 arranged in the outer layer flow path 39 are formed in a spiral shape turning in the same direction, and arranged in the middle layer flow path 38. The continuous screw 43 is formed in a spiral shape that turns in the opposite direction.
[0025]
The inner layer flow path 37 of the inner layer tubular cylinder 32 includes a spiral flow path 37 a formed by the continuous screw 42 and a linear flow path 37 b surrounded by the continuous screw 42. Are arranged at a plurality of locations, the introduction port 35 is connected to the inner layer flow path 37, and the discharge port 36 is connected to the outer layer flow path 39.
[0026]
The operation of the dryer 5 will be described below. In a state where the main body cylinder 31 is rotationally driven around the axis, the granulated sludge 4 and the circulating gas 6 are supplied from the inlet 35 to the inner layer flow path 37 of the main body cylinder 31. A part of the circulating gas 6 flowing in the vicinity of the inner peripheral surface of the inner layer tubular cylinder 32 hits the continuous screw 42 to become a turbulent flow, or flows along the spiral channel 37a along the continuous screw 42 as a swirling flow. The granulated sludge 4 staying in the lower part of 32 is soared and the granulated sludge 4 is fluidized and dried while forming a fluidized layer of solid-gas mixed phase. In addition, the scraping plate 32a lifts and agitates the granulated sludge 4 staying in the lower part of the inner tubular cylinder 32 to promote formation of a fluidized bed by the circulating gas 6, thereby improving contact efficiency and drying efficiency. .
[0027]
The circulating gas 6 flowing through the linear flow path 37b is air-dried while conveying the granulated sludge 4 soared to the downstream side. The granulated sludge 4 transported by the circulating gas 6 gradually falls to land on the inner layer tubular body 32 and is returned to the upstream side of the inner layer channel 37 by the continuous screw 42.
[0028]
In this way, the granulated sludge 4 repeatedly moves the inner layer flow path 37 to the main body cylinder 31 while repeatedly repeating the movement of the inner layer flow path 37 to the downstream side by the circulating gas 6 and the movement to the upstream side by the continuous screw 42. Since it flows to the downstream side of the end and stays in the machine for a long time while repeating fluidized drying and airflow drying, the drying efficiency of the granulated sludge 4 is increased.
[0029]
The granulated sludge 4 that has reached the other end of the main body cylinder 31 flows into the adjacent middle layer flow path 38 through the communication port 40 together with the circulating gas 6. The granulated sludge 4 that receives the upstream conveying action by the continuous screw 43 and the downstream conveying action by the circulating gas 6 in the middle layer flow path 38 is divided into the upper and lower inner tubular cylinders 32, the middle tubular cylinder 33, and the continuous screw 43. Since the flow path formed in a spiral shape is moved to the downstream side while forming a fluidized bed of a solid-gas mixed phase with the circulating gas 6 and realizes both fluidized bed drying and airflow drying, the circulating gas 6 And the contact efficiency and drying efficiency of granulated sludge become very high.
[0030]
Next, the granulated sludge 4 and the circulating gas flow into the outer layer flow path 39 through the communication port 41, and fluidized bed drying and air flow drying while flowing in the outer layer flow path 39 in a direction opposite to the flow of the middle layer flow path 38. , And flows out from the outer layer passage 39 to the outside of the main body drum 31 through the discharge port 36.
[0031]
Therefore, the residence time of the granulated sludge 4 is increased by the upstream conveying action of the continuous screws 42, 43, and 44, and high contact efficiency and drying efficiency are realized by the actions of both fluidized bed drying and airflow drying. Thus, the volume of the main body drum 31 can be reduced and the dryer 5 can be downsized.
[0032]
Further, the granulated sludge 4 is transported to the downstream side only by the transport action of the circulating gas 6 in the state in which the granule sludge 4 is transported to the upstream side by the continuous screws 42, 43, 44 inside the main body 31. Therefore, the sludge having a large undried weight and low fluidity is not discharged outside the machine until the weight is reduced by sufficient drying, so that the dry granulated sludge 12 has substantially the same weight and particle size.
[0033]
The main body cylinder 31 has multi-layered flow paths 37, 38, 39, so that the structure itself has heat insulation, and the circulation flows from the inner layer flow path 37 to the middle layer flow path 38 and from the outer layer flow path 39 to the outside. Since the gas 6 is deprived of heat by heating the granulated sludge 4 and the temperature gradually decreases, the temperature in the outer layer tubular body 34 becomes lower, and there is no need to install a heat insulating material such as a caster as in the prior art. The weight of the device can be reduced.
[0034]
As shown in FIG. 3, the inner layer tubular body 32 can be formed only by a spiral channel 37 a in which the inner layer channel 37 is formed by a continuous screw 42 by inserting an inner cylinder 45 therein.
[0035]
In this case, the entire flow path of the main body cylinder 31 is a spiral flow path, and the granulated sludge 4 forms a fluidized bed of a solid-gas mixed phase with the circulating gas 6, and functions of both fluidized bed drying and airflow drying. Move downstream while embodying.
[0036]
【The invention's effect】
As described above, according to the present invention, the granulated product is moved to the downstream side by forming a solid-gas mixed phase fluidized bed by the upstream conveying action by the continuous screw and the downstream conveying action by the carrier gas. Therefore, it is possible to embody the effects of both fluidized bed drying and airflow drying, and the contact efficiency and drying efficiency of the carrier gas and the granulated material become very high, and the volume of the main body is reduced and the dryer is downsized. it can. In addition, the granulated product is transported to the downstream side only by the transport action by the carrier gas, so that the granulated product having a large undried weight and low fluidity is discharged out of the machine until the weight is reduced by sufficient drying. Since this is not done, the weight and particle size of the dried granulation can be made approximately equal. Since the structure itself has a heat insulating property by forming a multi-layer flow path in the main body, it is not necessary to install a heat insulating material such as a caster, and the weight of the apparatus can be reduced. Agitation of the granulated product with a scraping plate promotes formation of a fluidized bed and improves contact efficiency and drying efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a drying facility in an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a dryer in the same embodiment.
FIG. 3 is a cross-sectional view of a dryer according to another embodiment of the present invention.
FIG. 4 is a schematic view showing the shape of a continuous screw in the dryer of the present invention.
[Explanation of symbols]
4 Granulated sludge 5 Dryer 6 Circulating gas 12 Dry granulated sludge 31 Main body cylinder 32 Inner layer tubular cylinder 32a Scrape plate 33 Middle layer tubular cylinder 34 Outer layer tubular cylinder 35 Inlet port 36 Outlet port 37 Inner layer channel 37a Spiral channel 37b Straight channel 38 Middle layer channel 39 Outer layer channel 40, 41 Communication port 42, 43, 44 Continuous screw

Claims (3)

A plurality of tubular cylinders are arranged concentrically to form a main body cylinder, and a granulated product to be dried and a carrier gas inlet of a heat source are connected to one end of the main body cylinder, and a dried granulated product and carrier are connected to the other end. Gas exhaust ports are connected, and each tubular cylinder is divided into main body cylinders to form flow paths in multiple layers, and each layer flow path is connected alternately at communication ports that are formed on one end side or the other end side of each tubular cylinder. Then, each layer channel is formed as a single channel, and a continuous screw is arranged on the inner surface of each tubular cylinder to form each layer channel in a spiral shape. It is formed in a spiral shape that transports the granulated material to the upstream side of the innermost, and the innermost layer flow channel formed inside the innermost tubular cylinder is formed by a continuous screw and a linear shape surrounded by the continuous screw The inlet is connected to the innermost layer channel, and the outermost channel is connected to the outermost channel. Constituted by connecting the outlet to the flow path, while flowing granulated material is to the downstream side while repeating the movement to the upstream side due to the movement and the continuous screw to the downstream side of the flow path by the carrier gas repeatedly, A granulation dryer characterized by repeating fluidized drying and airflow drying .   2. The granulator / dryer according to claim 1, wherein linear scraping plates along the axial direction are arranged at a plurality of locations on the inner surface of the innermost tubular cylinder.   The granulation dryer according to claim 1 or 2, wherein an inner cylinder is inserted into the innermost tubular cylinder and the innermost layer channel is formed only by a spiral channel formed by a continuous screw. .

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