JP5171531B2 - Asphalt pavement waste recycling dryer - Google Patents

Description

  The present invention relates to a dryer for regenerating asphalt pavement waste that heats and regenerates road pavement waste.

  Asphalt pavement waste material (hereinafter referred to as “waste material”) dug and raised by road construction or the like is heated and regenerated using a dryer for regenerating asphalt pavement material as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 9-59913). The This regeneration dryer includes a cylindrical drum that is rotatably and tiltably supported. A burner is disposed at a front end of the drum on the waste material input side through a combustion chamber having a predetermined length, and a drum inner peripheral wall is provided. Scattering blades for scraping up waste materials are provided around almost the entire area. While scraping the waste materials thrown into the drum while rolling down with the scraping blades, contact with hot air sent from the burner. Waste materials are regenerated by heating to a predetermined temperature.

  As described above, the conventional asphalt pavement waste material recycling dryer has a combustion chamber between the drum and the burner, and the mainstream is that the scraping blades are provided around the entire inner peripheral wall of the drum. Care is taken to prevent thermal degradation of the asphalt in the waste as much as possible by supplying hot air of a predetermined temperature into the drum while forming a flame so as not to heat the waste.

  By the way, the problem in heating the waste material is that the asphalt content in the waste material melts and becomes sticky and adheres to and accumulates on the drum inner wall and blades. In particular, the vicinity of the waste material input part of the drum is a temperature region where adhesion is most likely to occur, and a large amount of waste material adheres and accumulates in this region. Further, since the waste material with a fine particle size contains a large amount of asphalt, during the heating and regeneration of this waste material, the waste material adhering in the vicinity of the waste material input portion of the drum is intense and the adhesion to the blades in the latter half of the drum also increases. If the adhesion to the drum inner wall and the blades increases, the scraping function of the blades will be impaired, and if the lump of adhering material is peeled off and mixed into the product, the quality of the product will be adversely affected.

As a measure for preventing the waste material from adhering to the drum inner wall and blades, the present applicant has proposed a dryer for asphalt pavement waste material recycling as disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 2006-45845). This regenerative dryer eliminates the combustion chamber, which has been required in the past, and attaches the inner cylinder in the drum to form a burner flame in the inner cylinder. By heating with the radiant heat from the heat source, the heat efficiency is increased to save energy, and heat absorption to the waste material is accelerated to prevent the waste material from adhering to the drum inner wall. As a result of the actual machine operation, it was also confirmed that the waste material adhesion in the drum tends to be reduced as compared with the conventional case when the inside of the drum is in a high temperature atmosphere of direct fire.
Japanese Patent Laid-Open No. 9-59913 JP 2006-45845 A

  However, it has been confirmed that the inner cylinder covering the flame of the regeneration dryer is exposed to a high temperature and deformed, and if the inner cylinder is eliminated, there is a concern about thermal deterioration due to overheating of the waste material.

  In view of the above points, an object of the present invention is to provide an asphalt pavement waste material recycling dryer that can prevent thermal degradation due to overheating of the waste material as much as possible even if the waste material is directly heated by forming a flame in the drum.

In order to solve the above-described problems, in the asphalt pavement waste material recycling dryer according to claim 1 according to the present invention, a burner is disposed at one end of a drum that is rotatably supported so as to be supplied to the drum. In an asphalt pavement waste material recycling dryer in which a waste material conveyor is disposed below the burner and hot air and waste material flow in the same direction in the drum to heat and recycle the waste material, the hot air supply burner is connected to one end of the drum without going through the combustion chamber. The waste material is heated by forming a burner flame in the drum, and a circulation flue for circulating a part of the exhaust gas in the drum is connected to the exhaust flue downstream of the drum. flue bifurcated on the way, and inserts the tip into the drum at a position where the lower sides of the burner, flows down the exhaust gas to be circulated is introduced into the flame and the drum of the burner waste It is characterized by being configured to blow between.

According to the asphalt pavement waste material recycling dryer according to claim 1 of the present invention, the burner for supplying hot air is disposed not at the combustion chamber but at one end of the drum to form a burner flame in the drum to heat the waste material. The circulation flue for circulating a part of the exhaust gas in the drum is connected to the exhaust flue downstream of the drum, and the circulation flue branches in the middle, and the tip of the circulation flue is located below the burner. Since the exhaust gas to be circulated is inserted between the flame of the burner and the waste material that flows into the drum and flows down, the waste material caused by the burner flame is reduced by the exhaust gas whose temperature has decreased. Overheating can be suppressed and thermal degradation of waste materials can be prevented as much as possible. Also, by branching the circulation flue, the diameter of the circulation flue at the connecting portion with the drum becomes small, and it is easy to arrange in the empty space on the lower side of the burner.

  The asphalt pavement waste material recycling dryer of the present invention employs a co-current heating type dryer that allows hot air and waste material to flow in the same direction in a drum that is rotatably supported in an inclined manner. The burner for supplying hot air is arranged at one end of the drum without passing through the combustion chamber so that a burner flame is formed in the drum. Further, the drum in a range where the burner flame is formed is an area having no scraping blades.

  A circulation flue that circulates a part of the exhaust gas into the drum is connected to the exhaust flue downstream of the drum, while the other end of the circulation flue is connected to a position lower than the burner at the drum end for circulation. The exhaust gas is blown between the burner flame and the waste material flowing down the drum. In addition, the circulation flue is bifurcated in the middle to have a small diameter, and it is preferable that exhaust gas can be blown in a wide range between the flame of the burner and the waste material flowing down in the drum when connected to both lower sides of the burner. .

  When the waste material is recycled using the asphalt pavement waste material recycling dryer, if the waste material is put into the drum, the thrown-down waste material flows down so as to slide downstream along the drum inclination in an area where there is no scraping blade. On the other hand, a burner flame is formed in the drum, and the waste material does not directly touch the burner flame, but is directly exposed to the high heat of the burner flame.

  At this time, a part of the relatively low temperature exhaust gas discharged from the drum is blown between the burner flame and the waste material flowing down in the drum through the circulation flue, and the waste material is exposed to the high heat of the burner flame as much as possible. Suppresses and prevents thermal degradation due to overheating.

  Then, when the waste material reaches the substantially central portion of the drum, the waste material rolls down to the downstream side of the drum while being scraped up by the scraping blades, and is heated to a desired temperature by being exposed to hot air from the burner. .

  In this way, by blowing a part of the relatively low temperature exhaust gas between the burner flame and the waste material flowing down in the drum, overheating of the waste material exposed to the high heat of the burner flame is suppressed, and thermal degradation of the waste material is suppressed. It can prevent as much as possible.

  Embodiments of the present invention will be described below with reference to the drawings.

  Reference numeral 1 in the figure denotes an asphalt pavement waste material recycling dryer that heats and recycles waste material, and a cylindrical drum 2 is rotatably supported by a support roller 4 on a machine base 3 and is driven by a drive device (not shown). It is driven to rotate at a predetermined speed. The front end of the drum 2 is provided with a waste material conveyor 5 for supplying waste material into the drum 2, and a burner 6 for supplying hot air is provided without using a combustion chamber as provided in a conventional regeneration dryer. Then, the tip of the burner 6 faces the drum 2, a burner flame having a predetermined length is formed inside the drum 2, and the waste material is directly heated.

  Further, at least a range in which the burner flame is formed, for example, a range of about 1/5 to 1/3 of the drum length from the front end of the drum 2 is an area having no scraping blades in the drum 2. In order to prevent spillage of waste material from the front end portion of the drum 2, a check blade having no scraping effect may be attached. Also, a plurality of appropriately shaped scraping blades 7 for scraping the waste material are provided around the inner peripheral wall of the latter half of the drum 2.

  Reference numeral 8 denotes an exhaust flue that guides exhaust gas discharged from the drum 2 to a dust collector, an exhaust fan, and a chimney (not shown) downstream. A part of the exhaust gas is transferred to the front end of the drum 2 in the exhaust flue 8. One end of the circulating flue 9 to be circulated is connected, an exhaust fan 10 is interposed in the middle of the circulating flue 9, and the other end is lower than the burner 6 at the front end of the drum 2, and A relatively low temperature exhaust gas circulated from the circulation flue 9 by connecting and inserting to the upper part of the waste material conveyor 5 so that the opening of the circulation flue 9 faces the drum 2 is indicated by an arrow in FIG. The burner 6 is blown between the flame of the burner 6 and the waste material flowing down the bottom of the drum 2. In the illustrated example, the circulation flue 9 downstream of the exhaust fan 10 is bifurcated to have a small diameter, and the distal ends of the small diameter circulation flue branch pipes 9a and 9b are arranged on both lower sides of the burner 6, as shown in FIG. Is inserted into the drum 2.

  Then, when the asphalt pavement waste material regenerating dryer 1 is operated and the waste material is thrown into the drum 2 by the waste material conveyor 5, the thrown waste material flows down so as to slide on the bottom of the drum 2 in an area having no scraping blades. I will do it. At this time, the waste material is exposed to the high heat of the burner flame, but a part of the exhaust gas having a relatively low temperature is led to the front end portion of the drum 2 by the circulation flue 9, and the circulation flue branch pipes 9a and 9b are introduced. By blowing between the flame of the burner 6 and the waste material flowing down in the drum 2 from the front end opening, the overheating of the waste material is suppressed. When the waste material reaches the substantially middle part of the drum 2, the waste material rolls down to the downstream of the drum while being scraped up by the scraping blades 7, and is exposed to the hot air from the burner 6 during that time, and is exposed to a desired temperature. Until heated.

  Thus, the conventional combustion chamber and inner cylinder are eliminated, the flame of the burner 6 is formed in the drum 2, and the inside of the drum 2 is maintained in a high temperature atmosphere to improve heating efficiency and reduce waste material adhesion. A part of the relatively low temperature exhaust gas is circulated through the circulation flue 9 to the front end of the drum 2 and blown between the flame of the burner 6 and the waste material flowing down in the drum 2 to increase the heat of the burner flame. It is possible to suppress overheating of the waste material in the first half of the drum 2 exposed to the heat and to prevent thermal degradation of the waste material as much as possible.

It is a partially notched schematic block diagram which shows one Example of the dryer for asphalt pavement waste material reproduction | regeneration based on this invention. FIG. 2 is an enlarged view of the right side of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dryer for asphalt pavement waste recycling 2 ... Drum 5 ... Waste conveyor 6 ... Burner 7 ... Scraping blade 8 ... Exhaust flue 9 ... Circulation flue 9a, 9b ... Circulation flue branch pipe 10 ... Exhaust

Claims (1)

A burner is installed at one end of the drum that is rotatably supported and tilted, while a waste conveyor that supplies waste into the drum is installed at the lower part of the drum, and the waste is heated by flowing hot air and waste in the same direction in the drum. In the reclaimed asphalt pavement waste material recycling dryer, the burner for supplying hot air is arranged at one end of the drum without going through the combustion chamber to form a burner flame in the drum to heat the waste material, and at the downstream of the drum The exhaust flue is connected to a circulation flue that circulates a part of the exhaust gas in the drum, while the circulation flue branches in the middle, and the leading end of the exhaust flue enters the drum at the lower side of the burner. An asphalt pavement waste material recycling dryer characterized in that the exhaust gas to be inserted and circulated is blown between the burner flame and the waste material flowing into the drum and flowing down.

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