JP5484939B2 - Method for producing decadmium product from marine waste or sludge - Google Patents

Description

  The present invention relates to a method for treating aquatic waste and sludge generated during processing of seafood and the like, and in particular, a large amount of scallops and scallops discarded during processing, or a large amount of starfish captured with fish during fishing operations. The present invention relates to a method for removing cadmium contained in sludge or sludge and obtaining a detoxified product.

  Japanese Patent No. 3990644 (Patent Document 1) has already been proposed as a method for removing cadmium from marine waste. This invention introduces aquatic waste from a raw material supply part provided in the middle part of the processing cylinder main body, and suction and centrifugation provided hot air from a hot air inlet provided in the bottom part of the processing cylinder main body rotatably on the bottom part. Supplying to the blades, aquatic waste by dropping the aquatic waste, forced suction of hot air by suction and centrifugal blades, collision pulverization caused by tangential scattering of the pulverized waste and fluidized drying of the pulverized waste by hot air This is a method for removing cadmium remaining in a product.

Japanese Patent No. 3990644

    However, the invention of Patent Document 1 does not clearly indicate the state of the moisture content of the raw material for treating marine waste, and depending on the water content of the raw material for treatment, fluid pulverization drying in the treatment cylinder is not possible. As a result, the resulting dry powder product may vary, and sufficient cadmium removal may not be possible. In addition, since the hot air inlet faces the entire suction and centrifugal blade, the hot air speed supplied to the suction and centrifugal blade may not be sufficiently increased, and the hot air further accelerates the wear of the central blade portion. It required frequent maintenance.

  An object of the method of the present invention is to obtain a homogeneous dry powder product from which almost no cadmium has been removed, to suppress hot air wear at the central blade portion, and to supply hot air having a high wind speed to the drying tower.

In order to achieve the above object, the present invention has the following features.
That is, a predetermined amount of a dry powder product that has already been commercialized is added as a return amount to an aquatic residue raw material or sludge that has been processed into paste by a cutter in advance and measured to a predetermined amount, and stirred. A step of generating a return amount addition raw material, and a return amount addition raw material is provided at the lower part of the drying tower, and a hot air supply port is opened on both sides of the bottom of the drying tower. In the bottom portion, a centrifugal blade for collision that scatters the falling return added material in a tangential direction by high-speed rotation is opposed to the hot air supply port on both sides at the center of the rotating shaft that is rotatably supported by the side wall. The suction coarse granule accelerating blade that sucks the hot air and collects the return amount added raw material in the central part is put into a fluidized drying pulverizer fixed coaxially. With splashes in the direction And the step of vaporizing cadmium in the return amount additional raw material by drying by fluid hot air drying of the return amount additional raw material by the suction hot air of the suction coarse grain acceleration blade, and at least through these steps, the residual amount of cadmium A method for producing a cadmium product from aquatic waste or sludge, characterized in that a dry powder product removed is obtained.

  The return added material that is agitated and adjusted according to the moisture content of the treated raw material is charged into the fluidized drying pulverizer. In the fluidized drying pulverizer, hot air suction by the suction coarse particle accelerating blade and high speed of the centrifugal blade for collision with fluidized hot air are performed. Since the crushed return-added raw material is completely dried by the coarsening by repeated collision pulverization of the return-added raw material by rotation, most of the cadmium in the return-added raw material is vaporized by the flowing hot air per second. A homogeneous dry powder product can be obtained which is almost removed. In addition, since the hot air supply port faces only the suction coarse particle acceleration blade, hot air with high wind speed can be supplied to the drying tower, and the hot air does not directly hit the central impingement centrifugal blade. Hot air wear of the blade is suppressed.

  It is a system flow figure which implement | achieves the manufacturing method of the decadmium product by the marine-system waste or sludge which is this invention.   It is a cross-sectional view of the vicinity of the bottom of the drying tower of the fluidized drying pulverizer used in the method of the present invention.   It is a longitudinal cross-sectional view of FIG.

    The raw material to be treated by the method of the present invention is scallop urchin, squid goro, fish bones and internal organs discarded during processing, or aquatic waste such as starfish captured with fish during fishery operations or sludge. These processing raw materials are previously processed into a paste by a cutter. The fixed-quantity feeder 10 measures and supplies the processing raw material processed into the paste form to a predetermined amount according to the supply status. Then, the weighed processing raw materials are sent to the mixer 11 by a conveyor or the like (not shown).

  In the mixer 11, for example, a plurality of stirring blades are attached to two rotating shafts that rotate in opposite directions so that the angle can be adjusted, and the processing raw materials and the like that have been added are stirred and gradually fed to the feed screw 12. ing. In such a mixer 11, a predetermined amount of the dry powder product DP that has already been commercialized is added as a return amount to the weighed processing raw material.

例えば、処理原料１０００ｋｇで含水率７０％、固形分率３０％としたとき、これに乾燥粉体生成物ＤＰ（水分量７％）を加えて戻り量付加原料の見掛水分率を２５％に調整する分量としては、

となり、これを混合機１１内の処理原料１０００ｋｇ／ｈに加え撹拌した３５００ｋｇ／ｈが戻り量付加原料となる。
そして、混合機１１で撹拌されたこの戻り量付加原料が、フィードスクリュー１２を経て流動乾燥粉砕機１３に送られる。The return amount of the dry powder product DP to the mixer 11 is calculated by the following equation.

For example, when the moisture content is 70% and the solid content is 30% with a treated raw material of 1000 kg, the dry powder product DP (water content 7%) is added thereto, and the apparent moisture content of the return amount added material is 25%. As the amount to be adjusted,

This is added to the treated raw material 1000 kg / h in the mixer 11 and agitated 3500 kg / h becomes the return amount additional raw material.
Then, the return added material stirred by the mixer 11 is sent to the fluidized drying pulverizer 13 via the feed screw 12.

  The fluidized dry pulverizer 13 is provided with a return amount addition raw material inlet 15 at a lower portion of the drying tower 14, and the feed screw 12 protrudes into the drying tower 14 at the feed screw 12. It is arranged in the state. The feed screw 12 is connected to the mixer 11 on the other side, and transfers the return amount added raw material from the mixer 11 to the drying tower 14. By projecting the feed screw 12 in this way, the return amount additional raw material can be dropped to the center of the drying tower 14.

  Hot air supply ports 16 are individually opened on both sides of the bottom of the drying tower 14, and bifurcated hot air ducts 17 are connected to these hot air supply ports 16. A rotating shaft 18 is rotatably supported on the bottom side wall of the drying tower 14 via a bearing (not shown), and two impingement centrifugal blades 19 are end plates at the center of the rotating shaft 18. 20 are fixed back to back. Further, suction coarse particle acceleration blades 21 are fixed coaxially to the collision centrifugal blades 19 on both sides of the rotating shaft 18 and are simultaneously rotated counterclockwise. The collision centrifugal blades 19 function to coarsen the falling return added raw material by high-speed rotation and scatter in the tangential direction, and the suction coarse particle acceleration blades 21 are arranged on the respective blades facing each other with the collision centrifugal blades 19 in between. A twist of a predetermined reverse angle with respect to the axis is applied, and the rotation of the twist blades sucks hot air inward and collects the return-added raw material or coarse particles thereof at the center of the rotary shaft 18. Further, the end plate 20 functions to dam the return amount additional raw materials collected by the respective suction coarse particle acceleration blades 21 or coarse particles thereof and to create an upward air flow with hot air. The hot air supply port 16 is opened at a position facing the suction coarse particle acceleration blade 21. Thereby, hot air is blown only by the suction coarse grain acceleration blades 21 on both sides. Therefore, since hot air is not blown directly into the collision centrifugal blade 19, it is possible to prevent the wear and damage thereof, and further, the wind speed of the hot air can be accelerated even when the same wind pressure as that of the previous device is applied. .

  It is preferable that the inlet temperature of the hot air blown out from each hot air supply port 16 is set between 300 ° C and 430 ° C. The hot air speed is preferably about 25 m / s at the hot air supply port 16 and 6 to 9 m / s near the outlet of the drying tower 14.

  The method of the present invention is realized by the following steps. The processing amount of the aquatic waste material or sludge that has been previously processed into a paste by a cutter is measured by the quantitative feeder 10 as a processing material, and a predetermined amount is sent to the mixer 11. In the mixer 11, a predetermined amount of the dry powder product DP that has already been commercialized is added as a return amount to the processing raw material and stirred. In addition, the return amount added to the mixer 11 is calculated by the above-described calculation formula.

  The return amount added raw material thus agitated is gradually charged into the drying tower 14 of the fluidized drying pulverizer 13 through the feed screw 12. The returned additional material added falls in the drying tower 14. At the bottom of the drying tower 14, the coaxial collision centrifugal blade 19 and the suction coarse particle acceleration blade 21 rotate at high speed, and the hot air supply port 16 The hot air of around 400 ° C. is blown toward the suction coarse particle acceleration blade 21 only at a wind speed of around 25 m / s. The return amount added raw material falling in the drying tower 14 is coarsened by the high-speed rotation of the collision centrifugal blade 19 and scattered in the tangential direction, and repeatedly collides with the return amount additional raw material falling one after another. Repeat grinding and coarsening. At the same time, the return added material that has been crushed and dropped is collected at the central portion by the suction coarse grain acceleration blade 21 that sucks hot air efficiently, and falls on the rising airflow created by the end plate 20 one after another. Repeated collisions with coarsened return added material. As a result, the drying tower 14 is fluidized and pulverized at a high temperature and a high speed, and the return amount added raw material pulverized into fine dust is dried to a moisture content of 7% or less. Most of the cadmium in the return amount added raw material is at this second speed. It is vaporized by the flowing hot air and separated and scattered in the drying tower 14. In addition, since the front-end | tip part of the feed screw 12 is protrudingly arrange | positioned in the drying tower 14, a return amount addition raw material falls in the center part of the drying tower 14, and fluid drying can be performed reliably.

  After the product is collected from the upper part of the drying tower 14 by the cyclone 22 outside the tower, the cadmium-containing gas is separated and removed by passing through a bag filter or an electrostatic precipitator 24. In addition, the pulverized and dried powdery product is sent to the outside of the tower on the wind speed (4 m / s to 7 m / s) near the outlet of the drying tower 14 and separated into powder and gas by the cyclone 22. The dried powder product DP passes through the lock valve and the branch damper 23. Therefore, almost all of the cadmium is removed from the obtained dry powder product DP, and the amount of water and the particle shape are stabilized and uniform by controlling the inlet temperature based on the outlet temperature and the quantitative supply amount. The dry powder product DP is divided into a product and a return powder.

    A starfish was processed into a paste with a cutter and weighed to 500 kg with a quantitative feeder, and used as a processing raw material. It was 43.8 ppm when the cadmium content value of this processing raw material was measured by the atomic absorption photometry method. This treated raw material was charged into a mixer, and the amount of return of the mixer was added and stirred to obtain a return amount additional raw material. The mixer return amount was calculated by the above formula. The calculation conditions are as follows: the moisture content of the treated raw material 500 kg is 70%, and the dry powder product (water content 7%) that has been commercialized is added to adjust the apparent moisture content of the return added raw material to 25%. did. Thereby, the mixer return amount becomes 1250 kg / h, and the return amount additional raw material becomes 1750 kg / h. This return amount additional raw material was processed with the above-mentioned fluidized dry pulverizer, and the cadmium residual value of the obtained dry powder product was measured by atomic absorption spectrophotometry to be 0.1 ppm, which is a dry powder with almost no cadmium remaining. The product could be obtained.

  Since the dry powder product obtained by the method of the present invention is a safe product from which cadmium has been removed, by utilizing this as an agricultural fertilizer, the growth of agricultural products is greatly promoted and the yield is increased. Can contribute to the increase of

DESCRIPTION OF SYMBOLS 10 Fixed supply machine 11 Mixer 12 Feed screw 13 Fluidized drying pulverizer 14 Drying tower 15 Raw material input port 16 Hot air supply port 17 Forked hot air duct 18 Rotating shaft 19 Centrifugal blade 20 End plate 21 Suction coarse grain acceleration blade 22 Cyclone 23 Lock valve and branch damper 24 Bag filter or electrostatic precipitator

Claims (1)

Add a predetermined amount of dry powder product that has already been commercialized as a return amount to the aquatic residue raw material or sludge, which has been processed into paste by a cutter in advance and weighed to a predetermined amount. The step of generating the additional raw material, and the return amount of the additional raw material are provided at the lower portion of the drying tower, and the inlet of the additional amount of the additional raw material is provided, and hot air supply ports are opened on both sides of the bottom of the drying tower. In the center of the rotating shaft supported on its side wall, the colliding centrifugal blades that scatter the return amount added raw material falling in a tangential direction by high-speed rotation are arranged on both sides of the hot air so as to face the hot air supply port. The suction coarse grain accelerating blade collecting the return amount added raw material in the central part is fed into the fluidized drying pulverizer fixed coaxially, and the return amount added raw material is dropped and tangentially formed by the collision centrifugal blade. Collisions caused by splashes And the step of vaporizing the cadmium in the return amount additional raw material by the flow hot air drying of the return amount additional raw material by the suction hot air of the suction coarse-grain acceleration blade, and the residual amount of cadmium is removed through at least these steps. A method for producing a cadmium product from marine waste or sludge, characterized in that a dry powder product is obtained.

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