JP2005114327A - Drying method and drying equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, where the destruction of a film requires heat treatment in an autoclave as a cell membrane needs to be destroyed for dewatering since, although high-water-content wastes typified by sewage sludge are mechanically dewatered to a normal cake state and are apparently in a dried-out state, 75-85% moisture is still contained in the membrane. <P>SOLUTION: This drying method comprises a process for dropping a drying object into a catch pan for rotating the drying object in an airtightly sealed space against the atmosphere, integrally rotating the drying object deposited on the catch pan with the catch pan for scattering to the periphery, and allowing the drying object to collide against a wall and adhere to it surrounding the catch pan; and a process for spraying the mixed gas of superheated steam and combustion exhaust gas to the scattered drying object and for swelling and drying the drying object adhering to the wall and scraping off the drying object adhering to the wall by a bowl type scraper arranged below the catch pan, and dropping the scraped drying object downward from a hole provided at the bottom of the scraper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for drying a mud, and more particularly, to a method and apparatus for drying a mud containing a lot of moisture such as industrial wastewater and sewage sludge.

High water content waste represented by sewage sludge is usually mechanically dehydrated to the cake state and apparently appears to be papasa, with a seemingly low moisture content, but it actually contains 75-85% moisture. Yes.
The water structure of organic sludge can be classified into water outside the cell membrane particle and water inside the particle, and the water outside the cell membrane particle can be easily dehydrated by mechanical pressure, but the water inside the membrane can be easily removed by mechanical pressure. First, 75 to 85% of the water is the water in the membrane.
In order to dry and divert a high moisture content cake-like organic matter such as sewage sludge to a useful application, it is necessary to break down the cell membrane and create a situation in which the water in the membrane is easily diffused.
The invention of Patent Document 1 is disclosed as a method for dehydrating a cell membrane.
This method has a drawback that it is necessary to heat-treat in an autoclave, so that the processing cost is high, and it is difficult to continuously process in large quantities.

JP-A-6-246297

  The present invention has been made in view of such problems, and an object of the present invention is to provide a new drying method and a drying apparatus that can continuously process a large amount without using an autoclave.

The inventor has conducted extensive research on the above problems and found that the problems can be solved by the following means (1) to (10).
That is,
(1) A step of dropping the object to be dried in a rotating tray in a space kept confidential with respect to the outside air; and the object to be dried that has accumulated in the tray is rotated integrally with the tray and scattered around. A step of impacting and adhering to a barrier surrounding the tray, a step of blowing a mixed gas of superheated steam and combustion exhaust gas to the scattered dry matter and a dry matter adhering to the barrier, and expanding and drying the dry matter; Scraping dry matter adhering to the barrier with a scribber-type scraper disposed under the tray, and dropping the scraped dry matter from a hole provided at the bottom of the scraper. A method for drying mud.
(2) The method for drying a mud according to (1) above, wherein the tray and the sliver-type scraper are installed in multiple stages in the upper and lower directions, and the material to be dried dropped from each stage is sequentially and repeatedly dried. .
(3) A step of generating a reduced pressure space by rotating an impeller in a horizontally installed and fixed inner cylinder, and a mixture of an object to be dried and superheated steam and combustion exhaust gas is blown into the reduced pressure space, A step of expanding and drying the material to be dried while swirling the material to be dried in the inner cylinder, and discharging the material to be dried lightened by drying by rotation of the impeller. A method for drying mud.
(4) The outer cylinder which rotates to the to-be-dried object exit side of the said inner cylinder is connected, and the to-be-dried object discharged | emitted from the inner cylinder part is dried in two steps, Said (3) characterized by the above-mentioned. A method for drying mud.
(5) A housing that is kept secret from the outside air, a rotary shaft that is erected in the housing, a tray and a scraper that are integrally attached to the shaft, and a barrier that surrounds the tray and the scraper; A mechanism for injecting a mixed gas of superheated steam and combustion exhaust gas into the housing, a supply mechanism for supplying mud-like dry matter into the housing, and gas diffused by drying of the mud A drying apparatus for a mud, comprising a duct for discharging to the outside and a discharge port for discharging to-be-dried objects dropped from the bottom hole of the scraper located at the lowest position of the rotating shaft, And a plurality of scrapers are arranged in a plurality of stages on the rotating shaft, and the scrapers have a sliver-like shape with a bottom cut out, and are disposed under the tray so that the gap with the barrier is adjustable. Mud characterized by Of the drying apparatus.
(6) A horizontally disposed inner cylinder that is kept secret from the outside air, a rotating shaft that is horizontally disposed in the inner cylinder, an impeller that is integrally attached to the shaft, and an inner cylinder A mechanism for blowing a mixed gas of superheated steam and combustion exhaust gas into the inner cylinder, a mechanism for supplying a muddy object to be dried into the inner cylinder, and a rotating outer cylinder secretly connected to the object to be dried outlet side of the inner cylinder And a duct for discharging the gas diffused by drying of the muddy material to the outside of the housing and a discharge port for discharging the solid content at the end of the outer cylinder. .
(7) The mud according to any one of (5) to (6), wherein the mixer groove of the superheated steam and the combustion exhaust gas is a mechanism for sucking and mixing the combustion exhaust gas by injecting the superheated steam with an ejector. Equipment for drying the product.
(8) The mud drying apparatus according to any one of (5) to (7), wherein the combustion exhaust gas is an exhaust gas of a boiler that generates the superheated steam.
(9) The mud drying apparatus according to any one of (5) to (8) above, wherein the temperature inside the housing is adjusted by blowing exhaust gas from a boiler that generates the superheated steam into the housing. .
(10) The mud drying apparatus according to any one of (5) to (9), wherein the drying target supply mechanism is preheated with an exhaust gas from a boiler that generates the superheated steam.

The present invention has the following effects.
(1) Water in the cell membrane of organic sludge can be dehydrated and carbonized.
(2) A large amount of continuous processing can be performed economically and economically.

The present invention will be described with reference to the drawings.
There are basically two methods and devices in the present invention.
FIG. 1 is an explanatory view of a standing type method and apparatus.
FIG. 2 is an explanatory diagram of a horizontal type method and apparatus.
FIG. 1 is an explanatory diagram in the case of drying a muddy object to be dehydrated into a cake by a filter press or the like.
The cake is finely crushed by the crusher 1 and sent to the screw feeder 2. The screw feeder 2 is preheated with the combustion exhaust gas from the superheated steam generator 3, and the crushed cake sent to the screw feeder 2 is preheated to about 80 to 90 ° C. and supplied into the housing 4 of this apparatus. Falls into the saucer 5.
The tray 5 and the scraper 6 below the tray 5 are integrally attached to the rotating shaft 7 and are rotated integrally with the shaft. A plurality of the trays and scrapers are attached to the rotating shaft in multiple upper and lower stages.
The cake of the material to be dried that has fallen on the saucer collides with and adheres to the barrier 8 attached to the inner wall of the housing, which is given centrifugal force by the rotational force of the saucer and surrounds the saucer.
The number of rotations of the rotating shaft 7 is appropriately adjusted according to the moisture content, viscosity, etc. of the material to be dried.

  A mixed gas of superheated steam and high-temperature combustion exhaust gas is blown into the housing 4, and collides with a cake that is being dropped or attached to the barrier 8. The cake is swollen by this hot gas and the moisture in the cells begins to dry. For the expansion, it is preferable that the temperature of the mixed gas is higher. However, if the temperature is increased, the apparatus is seriously damaged and the running cost is increased. A range of approximately 200 to 1000 ° C. is preferred.

  The cake adhering to the barrier 8 is peeled off by the scraper 6 and falls down, falls again onto the lower tray, is given centrifugal force, and collides with the barrier again. The cake collides with the barrier, peeled off, dropped, and collided. While repeating such a process, the cake was evaporated, dried and lightened, and finally discharged together with the exhaust gas from the duct 9.

  As shown in the figure, the shape of the scraper is a shape with a hole in which the bottom of the mortar is cut out, and the heavy components such as the solid content of the dried residue and some undried cakes are placed in the lower tray from this hole. Then, the same process as in the first stage is repeated again and the drying proceeds. Repeat this process one after another, and the entire drying progresses, the lighter one goes out of the duct, the heavy solids fall down to the lower stage and accumulate in the bottom tray, and fall down from here , It will be discharged outside.

  Since the drying atmosphere of the present invention consists of a mixed gas of superheated steam and heated exhaust gas, it is substantially an oxygen-free atmosphere, and the material to be dried is carbonized without burning.

  The superheated steam forms normal-pressure steam with a boiler, which is heated through the boiler of the superheated steam generator 3 to be superheated steam. Heating uses gas heating, and the exhaust gas is mixed with superheated steam to serve as a heat source for drying in the housing. It is also used as a heat source for preheating the screw feeder.

  The light dry matter discharged together with the exhaust gas from the duct is collected by filtering through a filter. The exhaust gas that has passed through the filter is deodorized and discharged to the atmosphere.

  A part of the remaining hot gas in the housing can be used for heating a Stirling engine or the like installed outside the apparatus of the present invention.

FIG. 2 is a view for explaining the structure of the horizontal drying apparatus of the present invention.
FIG. 3 is a diagram illustrating a cross-sectional structure of the inner cylinder portion of FIG.
The material to be dried which is finely crushed by the crusher 1 and sent to the screw feeder 2 is supplied into a horizontally fixed inner cylinder 22 which is kept secret from the outside air.
In the inner cylinder, an impeller attached to a horizontal rotation shaft rotates, and a negative pressure is generated on the inner surface of the inner cylinder by this rotation.
As shown in FIG. 3, the material to be dried is discharged into the negative pressure space and heated by the mixed gas of superheated steam and high-temperature combustion exhaust gas sprayed in the direction tangential to the inner surface of the inner cylinder 22, and instantly expands. As a result, the cell membrane is destroyed and the intracellular moisture is dried while swirling in the tangential direction of the inner surface of the inner cylinder.
Due to the rotation of the impeller and the generated negative pressure, the object to be dried moves while being swiveled along the inner surface of the inner cylinder while being dried toward the outlet side of the inner cylinder. To be released.

The outer cylinder is rotating, and the inner surface is heated by the exhaust gas from the inner cylinder. The object to be dried discharged to the outer cylinder moves while being further dried toward the outlet while swiveling on the inner surface of the outer cylinder, and the object to be dried lightened by drying is discharged out of the duct together with the exhaust gas. The exhaust gas that has been filtered through the filter and passed through the filter is deodorized and released to the atmosphere.
The solid content of the dry residue falls down from the outlet of the outer cylinder and is discharged outside.

  Also in this example, the drying atmosphere is composed of a mixed gas of superheated steam and heated exhaust gas, so that the material to be dried is carbonized without burning, and is substantially oxygen-free.

  The light dry matter discharged together with the exhaust gas from the duct is collected by filtering through a filter.

  Part of the exhaust gas discharged from the outer cylinder can be diverted to heat the Stirling engine installed outside, and waste heat can be used effectively.

FIG. 4 is a diagram illustrating the structure of an ejector apparatus used for mixing superheated steam and exhaust gas according to the present invention.
Superheated steam is injected from the injection port with a narrowed cross section and injected outside from the discharge port. At this time, combustion exhaust gas is sucked from the suction port, so the mixed gas of superheated steam and combustion exhaust gas is discharged from the discharge port. Will be.

  The device of the present invention is not limited to cakes such as sewage sludge, and can be applied to drying all mud containing water. For example, sewage sludge, high-concentration factory effluent, food residues such as okara, beer and shochu lees.

(1) Suitable for dehydration and drying of water in the cell membrane of organic sludge.
(2) It is effective for drying waste containing a lot of water such as industrial wastewater and sewage sludge.
(3) Effective for drying sticky and poorly breathable materials such as okara and miso.
(4) Since the dried product is completely peeled off, the drying yield is extremely excellent.

FIG. 1 is an explanatory view (stand-up type) of the device of the present invention. FIG. 2 is an explanatory view (horizontal type) of the apparatus of the present invention. FIG. 3 is an explanatory diagram of the cross-sectional structure of FIG. FIG. 4 is an explanatory diagram of an ejector that mixes superheated steam and exhaust gas.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crusher 2 Screw feeder 3 Superheated steam generator 4 Housing 5 Receptacle 6 Scraper 7 Rotating shaft 8 Barrier 9 Exhaust gas duct 10 Receptacle 11 Receptacle 22 Inner cylinder

Claims (10)

  The step of dropping the object to be dried in a rotating tray in a space kept secret from the outside air, and the object to be dried accumulated in the tray are rotated integrally with the tray and scattered around the tray, A step of impacting and adhering to the surrounding barrier, a step of blowing a mixed gas of superheated steam and combustion exhaust gas to the scattered dry matter and the dry matter adhering to the barrier, and expanding and drying the dry matter; and attaching to the barrier A mud characterized in that it comprises a step of scraping the dried product with a scribber-type scraper disposed under the tray, and dropping the scraped dry product through a hole provided at the bottom of the scraper. Method of drying the product.   2. The method for drying a mud according to claim 1, wherein the tray and the sliver type scraper are installed in multiple stages up and down, and the object to be dried dropped from each stage is sequentially and repeatedly dried.   A step of rotating an impeller in a horizontally installed and fixed inner cylinder to generate a reduced pressure space; dropping an object to be dried into the reduced pressure space; and blowing a mixed gas of superheated steam and combustion exhaust gas; A step of expanding and drying the material to be dried while swirling the material to be dried around the inner periphery of the inner cylinder, and a step of discharging the material to be dried lightened by the drying to the outlet side by rotation of the impeller. A method for drying mud, characterized in that   The drying of the mud according to claim 3, wherein the outer cylinder rotating on the outlet side of the inner cylinder is connected to dry the substance to be dried discharged from the inner cylinder in two stages. Method.   A housing that is kept secret from the outside air, a rotary shaft that is erected in the housing, a tray and a scraper that are integrally attached to the shaft, a barrier that surrounds the tray and the scraper, A machine groove for injecting a mixed gas of superheated steam and combustion exhaust gas into the inside, a mechanism for supplying a muddy object to be dried into the housing, and a gas diffused by drying the muddy substance is discharged out of the housing. A muddy material drying device comprising a duct and a discharge port for discharging the material to be dried dropped from the bottom hole of the scraper located at the lowest position of the rotating shaft, wherein the tray and the scraper are The scraper is arranged in a plurality of stages on the rotating shaft, and the scraper has a sliver-like shape with a notch at the bottom, and is disposed under the tray so that the gap with the barrier is adjustable. Mud drying equipment .   A horizontal inner cylinder that is kept secret from the outside air, a rotary shaft that is horizontally installed in the inner cylinder, an impeller that is integrally attached to the shaft, and superheated steam in the inner cylinder And a mechanism for blowing a mixed gas of combustion exhaust gas, a mechanism for supplying a muddy object to be dried into the inner cylinder, a rotating outer cylinder secretly connected to the object to be dried outlet side of the inner cylinder, An apparatus for drying a muddy material, comprising a duct for discharging gas diffused by drying of the muddy material to the outside of the housing and a discharge port for discharging solid content at an end of the outer cylinder.   The mud drying apparatus according to any one of claims 5 to 6, wherein the mixing mechanism of the superheated steam and the combustion exhaust gas is a mechanism for sucking and mixing the combustion exhaust gas by injecting the superheated steam with an ejector.   The mud drying apparatus according to any one of claims 5 to 7, wherein the combustion exhaust gas is an exhaust gas of a boiler that generates the superheated steam.   The apparatus for drying a mud according to any one of claims 5 to 8, wherein the exhaust gas of the boiler that generates the superheated steam is blown into the housing to adjust the temperature inside the housing.   The mud drying apparatus according to any one of claims 5 to 9, wherein the drying object supply mechanism is preheated with an exhaust gas from a boiler that generates the superheated steam.