JP2008195584A - Cement calcination apparatus and method of drying highly hydrous organic waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more efficiently dry highly hydrous organic waste without risk of explosion of a drying apparatus or the like and without deterioration of thermal efficiency of a cement kiln. <P>SOLUTION: A cement calcination apparatus 1 is equipped with a crushing flash dryer 7 to which a combustion gas G drawn from a flue gas flow channel extending from the outlet duct of a prefiring furnace 4 of a cement kiln 2 to the outlet duct of a preheater 3 is supplied and which dries highly hydrous organic waste W such as highly hydrous organic sludge containing moisture in an amount of ≥40 mass%. The combustion gas G is brought into direct contact with the highly hydrous organic waste W and at the same time, the highly hydrous organic waste W is dried while being crushed. Thereby, drying efficiency can be improved by the increase of the specific surface area of the highly hydrous organic waste W and crushing efficiency can be improved by drying of the surface of the highly hydrous organic waste W. Accordingly, the total drying efficiency can be drastically improved. As the crushing flash dryer 7, a cage mill-type, chain percussion-type or revolving type crushing flash dryer can be used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cement baking apparatus capable of safely and efficiently drying high water content organic waste such as high water content organic sludge, and a method for drying high water content organic waste using the same device.

  Conventionally, various apparatuses and methods have been proposed in treating waste such as municipal waste with a cement baking apparatus. For example, in Patent Document 1, a part of the high temperature air of the clinker cooler is introduced into a drying device for drying waste such as municipal waste, and the exhaust from the drying device is returned to the clinker cooler again. A technique of using high-temperature air of a clinker cooler mixed with slag as combustion air for a cement kiln or a calciner is disclosed.

  Further, Patent Document 2 discloses that when combustible waste is incinerated with a cement baking apparatus, combustible waste is incinerated using a part of high-temperature air of a clinker cooler, and exhaust gas generated during the incineration process of waste. Has been described in which a preheater for heating the cement raw material is vented and slag generated during the incineration process of the waste is drawn out.

JP 63-151650 A Special table 2003-506299 gazette

  However, as described in the above-mentioned patent document, there is no problem when high-temperature air extracted from the clinker cooler is used for waste such as municipal waste or drying of combustible waste. When the above-mentioned high-temperature air is used for drying a highly water-containing organic waste, such as high-temperature air, the high-temperature air has a high oxygen concentration.

  Moreover, even if it is going to utilize the combustion exhaust gas after the preheater exit of a cement baking apparatus, since the temperature of the combustion exhaust gas of this area | region is about 450 degrees C or less, it is not suitable for drying of a high water content sludge.

  Furthermore, the extraction gas from the kiln bottom of the cement kiln is suitable for drying high water content organic waste because of its low oxygen concentration and high temperature of about 1000 ° C., but when the combustion gas is extracted from the kiln bottom, There was a problem that the thermal efficiency of the cement kiln deteriorated.

  Moreover, since the dry exhaust gas generated after drying organic sludge etc. contains a considerable amount of odor components, it is necessary to exhaust it after the deodorization treatment. In order to perform a deodorizing process, it is preferable to make the gas containing an odor component into 800 degreeC or more, and the method of deodorizing by introducing gas into combustion areas, such as a calcining furnace, is common. However, when cement kiln exhaust gas is used for drying organic sludge, etc., the dry exhaust gas has a low oxygen concentration. Therefore, if the dry exhaust gas is treated in the combustion region as described above, the combustion state deteriorates and the thermal efficiency of the cement kiln decreases. Therefore, there was a problem that it was not suitable.

  In addition to the above, the high water content organic sludge has a problem that it is difficult to efficiently dry the high water content organic sludge because it is a lump like clay containing 40% by mass or more of water and has a small specific surface area. It was.

  Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and there is no risk of the drying apparatus or the like exploding, the thermal efficiency of the cement kiln is not deteriorated, and the water content of the organic water is more efficiently increased. It is an object of the present invention to provide a cement baking apparatus capable of drying waste and a method for drying high water content organic waste.

  In order to achieve the above object, the present invention is a cement baking apparatus, wherein the combustion gas extracted from the exhaust gas flow path from the exit duct of the cement kiln calcining furnace to the exit duct of the preheater has a water content of 40% by mass or more. It is supplied so that it may be in direct contact with the high water content organic waste containing, and is equipped with the crushing airflow dryer which dries while crushing this high water content organic waste.

  The combustion gas extracted from the exhaust gas flow path from the exit duct of the cement kiln calcining furnace to the exit duct of the preheater has a low oxygen concentration of 2 to 8%. Since the temperature is 450 to 900 ° C., the high water content organic waste can be sufficiently dried. Further, since the combustion gas is not extracted from the kiln bottom of the cement kiln, the thermal efficiency of the cement kiln is not deteriorated. In addition, the combustion gas and high water content organic waste are brought into direct contact with each other, and at the same time, the high water content organic waste is dried while being crushed, thereby improving the drying efficiency by increasing the specific surface area of the high water content organic waste and increasing the water content. Combined with the improvement of crushing efficiency by surface drying of organic waste, the overall drying efficiency can be dramatically improved.

  In the cement baking apparatus, there are various methods such as a cage mill type, a chain blow type, or a swivel type as the crushing airflow dryer, but any type of dryer that performs crushing and airflow drying at the same time can be used. can do.

  The cement baking apparatus further includes a second exhaust gas flow path for returning the exhaust gas from the crushing air flow dryer to an exhaust gas flow path from an outlet duct of the cement kiln calcining furnace to an outlet duct of a preheater. it can. This eliminates the need for deodorizing the dried exhaust gas having a low oxygen concentration containing an odor component to a combustion region such as a calcining furnace, so that the thermal efficiency of the kiln is not deteriorated.

  In the cement baking apparatus, the high water content organic waste may be high water content organic sludge, and papermaking sludge, sewage sludge, bill pit sludge, food sludge and the like can be dried.

  The present invention also relates to a method for drying a high water content organic waste, wherein a part of the combustion gas is extracted from an exhaust gas passage from an outlet duct of a cement kiln calcining furnace to an outlet duct of a preheater, A part of the burned combustion gas is directly brought into contact with a high water content organic waste containing water of 40% by mass or more, and the high water content organic waste is dried while being crushed. According to the present invention, as described above, there is no possibility that the drying apparatus or the like will explode, the thermal efficiency of the cement kiln is not deteriorated, and the high water content organic waste is dried while being crushed more safely and efficiently. Can do.

  In the method of drying the high water content organic waste, the combustion gas after drying the high water content organic waste is returned to the exhaust gas flow path from the cement kiln calcining furnace outlet duct to the preheater outlet duct. Can do. Thereby, as described above, dry exhaust gas having an odor component can be treated without causing deterioration of the thermal efficiency of the kiln.

  In the drying method of the high water content organic waste, the high water content organic waste can be a high water content organic sludge such as papermaking sludge, sewage sludge, bill pit sludge, food sludge and the like.

  As described above, according to the present invention, there is no possibility that the drying apparatus or the like will explode, the thermal efficiency of the cement kiln is not deteriorated, and the cement baking apparatus capable of drying the high water content organic waste more efficiently. A method for drying high water content organic waste can be provided.

  FIG. 1 shows an embodiment of a cement baking apparatus according to the present invention. This cement baking apparatus 1 includes a cement kiln 2, a preheater 3, a calcining furnace 4, a cement raw material recovery cyclone 6, and a crushed airflow. A dryer 7, a high water content organic waste storage tank (hereinafter referred to as “waste storage tank”) 8, a dry organic waste recovery cyclone (hereinafter referred to as “dry matter recovery cyclone”) 11, and the like. The cement kiln 2, the preheater 3, and the calcining furnace 4 have the same functions as those of a conventional cement baking apparatus, and thus detailed description thereof is omitted.

  The cement raw material recovery cyclone 6 is provided in the front stage of the crushing air dryer 7, removes dust contained in the combustion gas G extracted from the exhaust gas flow path of the preheater 3, and removes the dust from the combustion gas G. 7 is provided for feeding.

  The crushing air dryer 7 supplies from the cement raw material recovery cyclone 6 while crushing high water content organic waste such as high water content organic sludge (hereinafter referred to as “waste”) W supplied from the waste storage tank 8. It is provided for drying by the combustion gas G. This crushing air dryer 7 has a supply port for the waste W at the upper part and a supply port for the combustion gas G from the cement raw material recovery cyclone 6 at the lower part, and makes the waste W and the combustion gas G contact in countercurrent. . In addition, a rotating shaft 7a and a striking chain 7b that is fixed to the rotating shaft 7a, extends in the horizontal direction by centrifugal force and rotates with the rotation of the rotating shaft 7a, and crushes the waste W are provided inside.

  The waste storage tank 8 is provided for temporarily storing high water content organic waste, and the high water content organic waste may be high water content organic sludge, such as papermaking sludge, sewage sludge, bill pit sludge, food Sludge etc. may be used.

  The blower 9 is provided for transporting the waste W crushed and dried by the crushed airflow dryer 7 to the preheater 3, and a roots blower or the like is used. The fan 12 is provided to return the dry exhaust gas G ′ discharged from the crushed airflow dryer 7 to the preheater 3 through the circulation duct 10.

  Next, operation | movement of the cement baking apparatus 1 which has the said structure is demonstrated, referring drawings.

  The cement raw material R is supplied to the preheater 3 of the cement firing device 1, preheated by the preheater 3, calcined in the calcining furnace 4, and fired by the cement kiln 2. On the other hand, the received waste W is temporarily stored in the waste storage tank 8.

  The fan 12 is operated, the combustion gas G of the cement kiln 2 is introduced into the cement raw material recovery cyclone 6, and the dust contained in the combustion gas G is recovered. The collected dust is returned to the pre-heater 3, and the combustion gas G after the dust is collected is supplied to the crushing air dryer 7.

  The waste W from the waste storage tank 8 is supplied to the upper part of the crushing air dryer 7 and the combustion gas G from the cement raw material recovery cyclone 6 is introduced from the lower part of the crushing air dryer 7. Since the temperature of this combustion gas G is about 800-900 degreeC, a high water content organic waste can fully be dried. Further, in the crushing air dryer 7, the waste W and the combustion gas G are in direct contact with each other in a counter flow, and the waste W is dried while being crushed by the striking chain 7b provided in the crushing air dryer 7. Therefore, the waste W is dried from the surface while increasing its specific surface area. Therefore, in addition to the improvement of the drying efficiency by increasing the specific surface area, the crushing efficiency is also improved by the surface drying of the waste W, and the overall drying efficiency is dramatically improved as compared with the conventional case. Moreover, since the combustion gas G introduced into the crushing air dryer 7 has a low oxygen concentration of about 2 to 8%, there is no possibility that the crushing air dryer 7 etc. will explode.

  Here, when the outlet gas temperature of the crushing air dryer 7 is too high, such as when the supply amount of the waste W to the crushing air dryer 7 is temporarily reduced, the front stage of the crushing air dryer 7 The cooling air C can be introduced.

  Next, the waste W that has been crushed and dried by the crushing airflow dryer 7 is collected by the dry matter collecting cyclone 11 and returned to the preheater 3 through the blower 9. Note that the collected waste W can be transported to a device other than the cement firing device 1 via the blower 9 for processing.

  On the other hand, the dry exhaust gas G ′ discharged from the crushing air dryer 7 is returned to the exhaust gas flow path from the lowermost cyclone 3 </ b> A to the second cyclone 3 </ b> B via the circulation duct 10 by the fan 12. Thereby, the deodorizing process of the odor component contained in the dry exhaust gas G ′ generated after drying the organic sludge or the like can be performed.

  In the above embodiment, the combustion gas G extracted from the exhaust gas flow path from the lowermost cyclone 3A to the second cyclone 3B is supplied to the crushed airflow dryer 7, but the second upstream of the preheater 3 Exhaust gas flow path from the cyclone 3B to the third cyclone 3C (combustion gas temperature is about 700 to 800 ° C.) or exhaust gas flow path from the third cyclone 3C to the fourth cyclone 3D (combustion gas temperature is 550 ° C. to 650 ° C. It is also possible to extract the combustion gas from the degree and supply it to the crushed airflow dryer 7.

  Further, the dry exhaust gas G ′ from the crushing air dryer 7 is not limited to returning to the exhaust gas flow path from the lowermost cyclone 3A to the second cyclone 3B, and is the same region as when the combustion gas G is extracted. Can be returned to.

It is the schematic which shows the whole structure of one Embodiment of the cement baking apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cement baking apparatus 2 Cement kiln 3 Preheater 3A Bottom cyclone 3B 2nd cyclone 3C 3rd cyclone 3D 4th cyclone 4 Calciner 5 Kiln bottom 6 Cement raw material recovery cyclone 7 Fracture air dryer 7a Rotary shaft 7b Stroke chain 8 Waste storage tank 9 Blower 10 Circulating duct 11 Dry matter recovery cyclone 12 Fan C Cooling air G Combustion gas G 'Dry exhaust gas R Cement raw material W Waste

Claims (6)

  Combustion gas extracted from the exhaust gas flow path from the outlet duct of the cement kiln calcining furnace to the outlet duct of the preheater is supplied so as to be in direct contact with the high water content organic waste containing water of 40% by mass or more. A cement baking apparatus comprising a crushing air dryer for crushing water-containing organic waste while crushing.   The exhaust gas from the crushing air dryer is provided with a second exhaust gas flow path for returning the exhaust gas from the exit duct of the cement kiln calcining furnace to the exit duct of the preheater. Or the cement baking apparatus of 2.   3. The cement baking apparatus according to claim 1, wherein the high water content organic waste is high water content organic sludge. A part of the combustion gas is extracted from the exhaust gas flow path from the exit duct of the cement kiln calcining furnace to the exit duct of the preheater,
A high water content organic waste characterized in that a part of the extracted combustion gas is brought into direct contact with a high water content organic waste containing water of 40% by mass or more and dried while crushing the high water content organic waste. How to dry things.   5. The high water content according to claim 4, wherein the gas after drying the high water content organic waste is returned to the exhaust gas flow path from the exit duct of the calcining furnace of the cement kiln to the exit duct of the preheater. How to dry organic waste.   6. The method for drying high water content organic waste according to claim 4, wherein the high water content organic waste is high water content organic sludge.

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