JP5376164B2 - Cement manufacturing apparatus and plastic volume reduction method using the same - Google Patents

Description

  The present invention relates to a cement manufacturing apparatus and a plastic volume reducing method using the same.

  Conventionally, a technology for reducing the volume of plastic by using exhaust gas heat of a boiler has been disclosed (for example, see Patent Document 1).

JP-A-7-214556

  However, in the above prior art, since the non-combustible dust is contained in the boiler exhaust gas, when dust is mixed into the waste plastic after volume reduction, and when the waste plastic after volume reduction is used as fuel, per unit volume There was a problem that the calorific value of was reduced. In addition, in cement production equipment, waste plastic may be supplied via a burner or nozzle that protrudes into the rotary kiln. In that case, the burner or nozzle is worn by nonflammable dust contained in the reduced waste plastic. There is also a problem.

  The present invention has been made paying attention to the above-mentioned problem, and its object is to reduce the volume of waste plastic without mixing incombustible dust of exhaust gas.

  In order to achieve the above object, in the present invention, a cement manufacturing apparatus provided with a rotary kiln is provided with plastic introduction means for introducing plastic to the outer peripheral side of the rotary kiln, and the temperature in the plastic introduction means is the softening of the plastic. More than the above, the plastic introduction means is a conveyor having a heat-resistant structure that is spaced apart from the outer surface of the rotary kiln and provided vertically below the rotary kiln.

  Since the volume of the plastic is reduced by using the kiln radiant heat, the incombustible dust can be prevented from being mixed into the plastic after the volume reduction, and the decrease in the heat generation amount and the wear of the apparatus can be avoided. Further, by reducing the volume and resolidifying by drying and softening, the crushability and the combustibility can be improved.

It is a schematic diagram of the cement manufacturing apparatus of this invention. 2 is a schematic diagram showing volume reduction / condensation of waste plastic in Embodiment 1. FIG. It is a schematic diagram which shows volume reduction and condensation of the waste plastic in Embodiment 1, Comprising: It is a schematic diagram which shows sectional drawing.

Hereinafter, preferred embodiments of the present invention will be described.
[Outline of cement production equipment]
FIG. 1 is a schematic view of the cement production apparatus of the present invention. The cement manufacturing apparatus includes a rotary kiln 1, a calciner 2, a burner 3, a hopper 5, a volume reduction conveyor 6, a crusher 7, a suspension preheater 8, and a clinker cooler 11.

  The cement raw material is put into the suspension preheater 8 and preheated, and is supplied to the rotary kiln 1 through the calcining furnace 2 provided at the kiln bottom 12 of the rotary kiln 1. The burner 3 extends from the front 13 of the rotary kiln 1 into the rotary kiln 1 and injects fuel into the rotary kiln 1. By burning the fuel injected from the burner 3, the cement raw material is fired and discharged as a clinker.

  Waste plastic is composed of various plastic waste materials such as food containers, daily necessities, plastics used in automobiles and home appliances, and is carried in by the truck 4 in a state of being roughly crushed in advance (the longest side is about 30 cm or less). In addition, waste plastics may be loaded on the volume reduction conveyor 6 by bulk loading, or may be loaded on the volume reduction conveyor 6 in a state of packing a certain amount. When a certain amount is packed, the volume reducing conveyor 6 may be omitted, and the packed waste plastic may be arranged as it is on the vertical lower side of the rotary kiln 1.

[Heating room]
Heating chambers 62 formed of heat insulating walls are provided on four vertical surfaces of the rotary kiln 1 that are vertically below, and prevent diffusion of radiant heat. The outer surface temperature of the rotary kiln 1 is 200 to 250 ° C., and the temperature in the heating chamber 62 is the Vicat softening point of waste plastic (JISK6740-1, JISK6740-2, JISK6900, JISK6921-1, JISK6922-1, JISK6924-1, JISK6924 -2, JISK7314-2: See Table 1) above, and about 200 ° C. Generally, waste plastic is mainly composed of thermoplastic general-purpose plastic. Since the softening point varies depending on the degree of polymerization, Table 1 shows typical examples.

  On the vertically lower side of the rotary kiln 1, a volume reducing conveyor 6 for conveying waste plastic is provided. The volume reducing conveyor 6 is a space between the rotary kiln 1 and the ground, is in the same direction as the axis of the rotary kiln 1, and extends in the heating chamber 62. Waste plastic is carried into the cement factory by the truck 4, stored in the hopper 5, and then transported from the kiln bottom 12 side to the kiln front 13 side by the volume reducing conveyor 6. The transported waste plastic is crushed by a crusher 7 provided on the front side 13 of the kiln and supplied as fuel into the rotary kiln 1 through the burner 3 together with other fuel such as coal.

[Volume reduction conveyor]
2 and 3 are views showing the volume reducing conveyor 6. The volume-reducing conveyor 6 is a heat-resistant conveyor that conveys waste plastic while being exposed to the outside. The volume reducing conveyor 6 is provided close to the rotary kiln 1, and among the plastic waste transported, the thermoplastic plastic is reduced by the radiant heat of the rotary kiln 1 while being transported by the volume reducing conveyor 6. In order to effectively reduce the volume of waste plastic, the distance between the volume reducing conveyor 6 and the rotary kiln 1 is set to a distance close to a temperature at which the volume of waste plastic can be reduced. For example, if the diameter of the rotary kiln 1 is D and the distance between the volume reducing conveyor 6 and the rotary kiln 1 is d, d ≦ D / 2.
The waste plastic is gradually heated as it moves from the kiln bottom 12 side to the kiln front 13 side on the volume reducing conveyor 6, and is dried, softened and reduced in volume, adheres to each other, and condenses into a lump.

  Waste plastic has a large volume per unit weight. Therefore, if the size of the waste plastic is excessive when blowing from the burner 3, the amount of air for transporting the waste plastic will increase. Therefore, the air for transportation is reduced by finely crushing the waste plastic by the crusher 7. Further, since the waste plastic is soft and bulky, it is assumed that the waste plastic is softened in advance in the volume reduction container 6 and reduced in volume and re-solidified and then crushed by the crusher 7.

  Thus, the volume is reduced and solidified by reducing and condensing in the volume reducing conveyor 6, thereby reducing the volume and making it hard enough to be pulverized by the crusher 7, together with fine coal powder, from the burner 3 into the rotary kiln 1. The fuel is easy to supply and easy to burn.

  The surface of the volume reducing conveyor 6 that contacts the waste plastic may be provided with irregularities. Concavities and convexities are also formed on the surface of the waste plastic reduced by the concavities and convexities, and crushing is facilitated when the solidified waste plastic is crushed by the crusher 7. At the same time, it is possible to reduce the adherence of waste plastic to the volume reduction conveyor 6, and the waste plastic reduced in volume and solidified can be easily discharged from the volume reduction conveyor 6.

[effect]
(1) (4) A cement manufacturing apparatus provided with a rotary kiln 1,
A plastic introduction means (volume reduction conveyor 6) for introducing plastic is provided on the outer peripheral side of the rotary kiln 1, and the temperature in the plastic introduction means (volume reduction conveyor 6) is equal to or higher than the temperature at which the plastic is softened. The means (volume-reducing conveyor 6) is a volume-reducing conveyor 6 having a heat-resistant structure provided at a distance from the outer surface of the rotary kiln 1 and provided vertically below the rotary kiln 1.
Thereby, the plastic can be dried and / or reduced in volume by using the radiant heat of the rotary kiln 1, and the properties suitable for crushability and combustibility can be obtained. Since incombustible dust does not enter the plastic after volume reduction, problems such as a decrease in the amount of heat generated by the dust and wear of the apparatus can be avoided. Further, the plastic introduction means can be provided with a simple configuration using a conveyor.
(2) The plastic is waste plastic. Waste plastics are inexpensive, but may have difficulties during crushing due to their various forms. By reducing the volume of the plastic beforehand by the radiant heat of the rotary kiln 1, it can be easily crushed.
(3) A crusher that crushes the plastic that has passed through the plastic introduction means (volume reduction conveyor 6) and a burner 3 that throws the plastic into the rotary kiln 1 are further provided. Through the rotary kiln 1 as fuel.
Thereby, waste plastic can be made into the fuel suitable for cement baking. The burner 3 may be connected to the calcining furnace 2 and the crushed plastic may be put into the calcining furnace 2.

DESCRIPTION OF SYMBOLS 1 Rotary kiln 2 Calciner 3 Burner 4 Truck 5 Hopper 6 Volume reduction conveyor 7 Crusher 8 Suspension preheater 11 Clinker cooler 12 Kiln bottom 13 In front of kiln 62 Heating chamber

Claims (4)

A cement manufacturing apparatus equipped with a rotary kiln,
A plastic introduction means for introducing plastic to the outer peripheral side of the rotary kiln is provided,
The temperature in the plastic introduction means is not less than the softening point of the plastic,
The cement manufacturing apparatus, wherein the plastic introduction means is a conveyor having a heat-resistant structure that is spaced apart from the outer surface of the rotary kiln and provided vertically below the rotary kiln. In the cement manufacturing apparatus according to claim 1,
The cement manufacturing apparatus, wherein the plastic is waste plastic. In the cement manufacturing apparatus according to claim 1 or 2,
A crusher for crushing the plastic that has passed through the plastic introduction means;
A burner for charging the plastic into the calcining furnace of the rotary kiln or the cement manufacturing apparatus,
The plastics crushed by the crusher are fed as fuel into the rotary kiln or the calciner through the burner. A rotary kiln installed in the cement production equipment;
A plastic introduction means for introducing plastic to the outer peripheral side of the rotary kiln;
The plastic introduction means introduces the plastic while being separated from the outer surface of the rotary kiln,
Due to the radiant heat of the rotary kiln, the plastic introduced to the outer peripheral side of the rotary kiln is dried, softened, reduced in volume and resolidified,
The plastic introduction method is a heat-resistant conveyor provided vertically below the rotary kiln. A plastic volume reduction method using a cement manufacturing apparatus.

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