JP2007070138A - Apparatus for thermal regenerative treatment of waste gypsum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for thermal regenerative treatment of waste gypsum which can change even a gypsum captured by a dust collector into a hemihydrate gypsum in a good yield together with a gypsum discharged from a rotary kiln, at the time of thermal regenerative treatment of a waste gypsum in the state of a gypsum dihydrate. <P>SOLUTION: This apparatus thermally regenerates the waste gypsum in the state of gypsum dihydrate by adopting a parallel flow heating rotary kiln 1. Also, the apparatus is provided with a temperature sensor 17 for detecting the temperature of exhaust gas at an exhaust gas duct 6, and a burner combustion controller for controlling the combustion amount of a burner 4 based on the exhaust gas temperature detected by the temperature sensor 17. The burner combustion amount is controlled so that the exhaust gas temperature is at a temperature at which the gypsum dihydrate is changed to a hemihydrate gypsum, and also the waste gypsum entrained by the exhaust gas is changed to a hemihydrate gypsum by flash drying to be captured and recovered by a dry cyclone 7 and a bag filter 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a waste gypsum heat regeneration processing apparatus that heats and recycles waste gypsum in the form of dihydrate gypsum obtained by crushing and separating waste gypsum board that is building waste.

  Conventionally, most of the waste gypsum board that is generated in large quantities due to the dismantling of buildings has been disposed of by landfill, etc., but the waste gypsum board is managed from stable industrial waste by the revision of the Waste Disposal Law. From the viewpoint of soaring processing costs associated with the shift to industrial waste and effective utilization of resources, it is desired to separate and recover gypsum from waste gypsum board.

By the way, gypsum is roughly classified into three types, dihydrate gypsum (CaSO ₄ · 2H ₂ O), hemihydrate gypsum (CaSO ₄ · 1 / 2H ₂ O), and anhydrous gypsum (CaSO ₄ ) depending on the difference in crystal water. When dihydrate gypsum is heated to about 130 ° C. or higher, it is rearranged to hemihydrate gypsum, and when heated to about 180 ° C. or higher, it is transferred to type II anhydrous gypsum via type III anhydrous gypsum. In addition, when hydration treatment is performed on hemihydrate gypsum, the hydration reaction proceeds rapidly and rearranges to dihydrate gypsum and hardens in a short time. Does not advance. It has been found that type III anhydrous gypsum absorbs moisture in the atmosphere strongly, so that it can be easily converted to hemihydrate gypsum if it is allowed to stand naturally.

  Gypsum such as gypsum board is in the form of dihydrate gypsum, and even if it is treated with water, it does not hydrate and does not harden. It can be cured in a short time, and can be effectively reused as, for example, a soil solidifying material.

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-122645), waste gypsum board or the like is heated to a predetermined temperature under atmospheric pressure or under pressure to form a half-water gypsum, and this half-water gypsum is used as a raw material for soil solidifying material. It describes what is effectively used. Patent Document 1 does not describe a specific device as a heating means. However, for example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-269299) and Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-136206) disclose a large number of documents. As shown, as a heat treatment apparatus for waste gypsum board, a rotary kiln having excellent heating efficiency is often used.

And as said rotary kiln, as also shown in Patent Document 2, the material is flowed from the direction opposite to the direction in which the hot air flows in the drum, and the burner combustion amount is set based on the heating material temperature discharged from the drum. A so-called countercurrent heating type rotary kiln is generally used.
JP 2001-122645 A JP 2004-269299 A JP 2004-136206 A

  However, the waste gypsum in the form of dihydrate gypsum obtained by crushing and separating waste gypsum board is fine powder, and when trying to heat it with a rotary kiln, the amount of waste gypsum covered with hot air is inevitably large. For example, according to experiments conducted by the present inventors, about 20 to 30% of the waste gypsum introduced into the rotary kiln is scattered downstream of the exhaust duct along with the exhaust gas. As a result, it was captured by the dust collector.

  Therefore, when a conventional countercurrent heating type rotary kiln is used, the gypsum discharged from the kiln can be transferred to hemihydrate gypsum in order to perform heating control based on the gypsum temperature at the kiln outlet, but the exhaust gas temperature Therefore, if the exhaust gas temperature is low, the waste gypsum that accompanies the exhaust gas cannot be transferred to hemihydrate gypsum, and if the exhaust gas temperature is high, part of the waste gypsum is difficult to proceed through the hemihydrate gypsum. It may be rearranged to type II anhydrous gypsum, and it is sufficiently predicted that gypsum captured by the dust collector cannot be translocated to hemihydrate gypsum with good yield.

  In view of the above points, the present invention is a waste gypsum that can displace gypsum captured by a dust collector together with gypsum discharged from a rotary kiln together with gypsum discharged from a rotary kiln with good yield when heating and regenerating waste gypsum in dihydrate gypsum. It is an object of the present invention to provide a heat regeneration processing apparatus.

  In order to solve the above-mentioned problems, the waste gypsum heat regeneration treatment apparatus according to claim 1 according to the present invention heat treats waste gypsum in the state of dihydrate gypsum obtained by crushing and separating waste gypsum board. A waste gypsum heat regeneration processing apparatus that regenerates as hemihydrate gypsum, having a co-current heating type rotary kiln equipped with a hot air supply burner on the gypsum supply side of a cylindrical drum that is rotatably supported in an inclined manner. A dust collector that captures the gypsum that is scattered is disposed downstream of the exhaust duct of the rotary kiln, and the exhaust duct is provided with a temperature sensor for detecting the exhaust gas temperature, and based on the exhaust gas temperature detected by the temperature sensor. There is also a burner combustion controller that controls the combustion amount of the burner, and gypsum that is captured by a dust collector by controlling the burner combustion amount so that the exhaust gas temperature becomes the temperature at which dihydrate gypsum is transferred to hemihydrate gypsum. It has to be recovered by rearrangement to gypsum are characterized.

  The waste gypsum heat regeneration treatment apparatus according to claim 2 is characterized in that the exhaust gas temperature of the rotary kiln is controlled to be 100 to 200 ° C, preferably 130 to 180 ° C.

  According to the waste gypsum heat regeneration treatment apparatus according to claim 1 of the present invention, the waste gypsum in the state of dihydrate gypsum obtained by crushing and separating the waste gypsum board is heat treated as a half-water gypsum. An apparatus for heating and regenerating waste gypsum to be regenerated, comprising a co-current heating type rotary kiln having a hot air supply burner on a gypsum supply side of a cylindrical drum rotatably supported by an inclination, and an exhaust duct of the rotary kiln A dust collector that captures the scattered gypsum is installed downstream of the exhaust duct, and the exhaust duct is provided with a temperature sensor for detecting the exhaust gas temperature, and the burner combustion amount is controlled based on the exhaust gas temperature detected by the temperature sensor. Burner combustion controller that controls the amount of burner burn so that the exhaust gas temperature becomes the temperature at which dihydrate gypsum is transferred to half-water gypsum, and the gypsum captured by the dust collector is also transferred to half-water gypsum. Since the gypsum discharged from the rotary kiln and the gypsum captured by the dust collector can be recovered by transferring the gypsum to the half-water gypsum in a high yield, most of the waste gypsum can be recycled to the half-water gypsum without waste. It can be used effectively for soil solidifying materials.

  Further, according to the waste gypsum heat regeneration treatment apparatus according to claim 2 of the present invention, since the exhaust gas temperature of the rotary kiln is controlled to be 100 to 200 ° C, preferably 130 to 180 ° C, it is discharged from the rotary kiln. Gypsum can be rearranged to hemihydrate gypsum, and waste gypsum scattered with exhaust gas from the rotary kiln can be rearranged to hemihydrate gypsum by airflow drying.

  The waste gypsum heat regeneration processing apparatus of the present invention employs a co-current heating type rotary kiln having a hot air supply burner on the gypsum supply side of a cylindrical drum rotatably supported by tilting. The exhaust duct of the rotary kiln is provided with a temperature sensor for detecting the exhaust gas temperature, takes in the exhaust gas temperature detected by the temperature sensor, and compares it with a preset exhaust gas temperature set value to determine the burner based on the difference value. A burner combustion controller is provided for controlling the amount of combustion.

  And when the waste gypsum in the state of dihydrate gypsum is heat-treated to make half water gypsum, first, the temperature at which the exhaust gas temperature setting value of the burner combustion controller is suitably transferred to the half water gypsum, For example, the temperature is set to 100 to 200 ° C., preferably 130 to 180 ° C. When waste gypsum is supplied while supplying hot air from the burner into the rotary kiln, a large amount of waste gypsum flows from the rotary kiln to the exhaust duct along with the exhaust gas. Because it is controlled by the temperature at which it is rearranged into hemihydrate gypsum, the waste gypsum accompanying the exhaust gas is heated to the temperature at which it is translocated to hemihydrate gypsum by airflow drying, and can be reused in downstream dust collectors. Is captured and recovered.

  In the rotary kiln of the co-current heating method, there is a correlation between the heating temperature of the gypsum discharged from the kiln and the exhaust gas temperature, and by controlling the exhaust gas temperature, the gypsum heating temperature can also be controlled without time lag. The temperature can be precisely controlled, thereby improving the yield of hemihydrate gypsum.

  In this way, if a parallel kiln rotary kiln is adopted and burner combustion amount control is performed based on the exhaust gas temperature, the heating temperature of the gypsum discharged from the rotary kiln can be controlled, and a large amount of air is scattered accompanying the exhaust gas. Waste gypsum can also be heated preferably by airflow drying, and it can be recovered by transferring the gypsum to hemihydrate gypsum with good yield. The waste gypsum can be effectively regenerated and used as a soil solidifying material.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the figure, reference numeral 1 denotes a rotary kiln of a co-current heating system that heats and recycles waste gypsum, and supports a cylindrical drum 2 having a large number of scraping blades (not shown) on its inner peripheral wall so that it can rotate freely. The hot hopper 3 on the side of the waste gypsum supply side of the drum 2 is provided with a burner 4 for supplying hot air, while the gypsum discharge of the drum 2 is driven by a drive motor (not shown). An exhaust duct 6 for exhaust gas exhaust is connected to the cold hopper 5 side, and a dust collector of a dry cyclone 7 and a bag filter 8, an exhaust fan 9, and a chimney 10 are disposed downstream of the exhaust duct 6. .

  A storage hopper 11 capable of supplying a fixed amount of waste gypsum is disposed on the hot hopper side 3 of the drum 1 so that a fixed amount of waste gypsum can be discharged and supplied into the drum 2 via a belt conveyor 12. On the cold hopper 5 side of the drum 2, a stock bin 13 for storing heated gypsum and a bucket elevator 14 for conveyance are disposed.

  Then, while supplying hot air from the burner 4 into the drum 2, the exhaust gas is sucked by the exhaust fan 9 at the end of the exhaust duct 6, and the high-temperature gas flow passing through the drum 2 is maintained, and the quantity is determined from the storage hopper 11. Waste gypsum that has been dispensed one by one is fed into the drum 2 by the belt conveyor 12, heated to a desired temperature while rolling down in the drum 2 while being scraped up by a scraping blade, discharged from the cold hopper 5 side, and bucket bucket elevator 14 to be stored in the stock bin 13. The exhaust gas from the drum 2 passes through the dry cyclone 7 and the bag filter 8 and captures gypsum accompanying the exhaust gas, and then releases the cleaned exhaust gas from the chimney 10 to the atmosphere.

  The gypsum captured by the dry cyclone 7 is discharged by the rotary valve 15 and stored in the stock bin 13 by an appropriate transfer means, and the gypsum captured by the bag filter 8 is also discharged by the screw feeder 16 as appropriate. Are stored in the stock bin 13 by the transfer means. In addition, the collected gypsum is not stored in the stock bottle 13 together, but the fine particles captured by the dry cyclone 7 and the fine particles captured by the bag filter 8 are managed for each particle size and reused. You can also.

  Further, the exhaust duct 6 is provided with a temperature sensor 17 for detecting the temperature of the exhaust gas derived from the drum 2, and the exhaust gas temperature detected by the temperature sensor 17 is captured and compared with a preset exhaust gas temperature set value. And the burner combustion controller 18 which controls the combustion amount of the burner 4 based on the difference value amount is provided. Then, the burner combustion amount is controlled by setting the exhaust gas temperature to a temperature at which dihydrate gypsum is transferred to hemihydrate gypsum, that is, about 100 to 200 ° C., preferably about 130 to 180 ° C.

  Thus, when waste gypsum in the form of dihydrate gypsum is heated and regenerated as semi-hydrate gypsum by the above apparatus, first, the burner 4 is combusted while the drum 2 of the rotary kiln 1 is driven to rotate, and the inside of the drum 2 is burned. While the hot air is fed into the drum 2, the powdery waste gypsum is discharged from the storage hopper 11 and is sequentially supplied into the drum 2 by the belt conveyor 12, and the waste gypsum is heated by a cocurrent heating system. At this time, the burner combustion controller 18 adjusts the exhaust gas temperature detected by the exhaust duct 6 to a temperature at which dihydrate gypsum is transferred to hemihydrate gypsum, for example, 100 to 200 ° C., preferably 130 to 180 ° C. Control burner combustion.

  In addition, some of the waste gypsum supplied to the rotary kiln 1 is scattered in the exhaust duct 6 along with the exhaust gas during heating in the kiln, but the exhaust gas temperature is the temperature at which dihydrate gypsum is converted to hemihydrate gypsum. Therefore, the waste gypsum is dislocated to hemihydrate gypsum by airflow drying and is captured by the downstream dry cyclone 7 and the bag filter 8.

  On the other hand, since the gypsum discharged from the drum 2 is a co-current heating system, if the exhaust gas temperature is controlled, the heating is controlled without a time lag, so that the heating temperature is stable and can be translocated to the semi-hydrate gypsum with a high yield. The hemihydrate gypsum discharged from the drum 2 and the hemihydrate gypsum captured by the dry cyclone 7 and the bag filter 8 are collected and stored in the stock bin 13 and effectively used as a soil solidifying material. .

  In order to control the burner combustion amount based on the temperature of the heated material discharged from this drum, the waste gypsum adopts a co-current heating type rotary kiln 1 and the exhaust gas temperature is changed to the temperature at which dihydrate gypsum is transferred to hemihydrate gypsum. Since the burner combustion amount is controlled as described above, not only gypsum discharged from the rotary kiln 1 but also gypsum captured by the dry cyclone 7 and the bag filter 8 can be transferred from dihydrate gypsum to hemihydrate gypsum with high yield.

  In the rotary kiln 1 of the cocurrent heating method, since there is a burner 4 on the waste gypsum input side, waste gypsum containing moisture is heated and dried all at once, so that the gypsum hardly adheres to the inner wall of the drum 2 and the countercurrent heating method. There is an advantage that the adhesion of the waste gypsum in the vicinity of the inlet of the drum 2 can be reduced as compared with the one.

It is explanatory drawing which shows the Example of the heat reproduction processing apparatus of the waste gypsum based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotary kiln 2 ... Drum 4 ... Burner 6 ... Exhaust duct 7 ... Dry cyclone (dust collector) 8 ... Bag filter (dust collector)
11 ... Waste gypsum storage hopper 13 ... Stock bottle 17 ... Temperature sensor 18 ... Burner combustion controller

Claims (2)

  A waste gypsum heat regeneration treatment device that recycles waste gypsum in the form of dihydrate gypsum obtained by crushing and separating waste gypsum board to recycle it as semi-water gypsum. A rotary kiln with a co-current heating system equipped with a hot air supply burner on the gypsum supply side of a drum-like drum, and a dust collector that captures the scattered gypsum is arranged downstream of the exhaust duct of the rotary kiln, while the exhaust duct Is equipped with a temperature sensor for detecting the exhaust gas temperature, and a burner combustion controller that controls the burner combustion amount based on the exhaust gas temperature detected by the temperature sensor. The waste gypsum heat regeneration processing apparatus, wherein gypsum captured by a dust collector by controlling the burner combustion amount so as to achieve a temperature can be transferred to hemihydrate gypsum and recovered   2. The waste gypsum heat regeneration treatment apparatus according to claim 1, wherein the exhaust gas temperature of the rotary kiln is controlled to be 100 to 200 ° C., preferably 130 to 180 ° C. 3.

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