JP2004292200A - Combustion improving method of inflammable fuel in burning process of cement clinker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion improving method of an inflammable fuel in the burning process of a cement clinker that suppresses elevation, lowering or variance of the combustion gas temperature and further prevents the damage of a kiln brick when inflammable wastes such as woods or plastics are used as an auxiliary fuel in place of pulverized coal. <P>SOLUTION: The inflammable fuel uses the pulverized coal as a main fuel and uses a wood crushed material and a plastic crushed material as auxiliary fuels wherein the net calorific value of the pulverized coal is 5,000-8,000 kcal/kg, the net calorific value of the wood crushed material is 2,500-5,000 kcal/kg and the net calorific value of the plastic crushed material is 5,000-13,000 kcal/kg. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
The present invention relates to the pulverized coal as a main fuel, it relates to a combustion improving method of combustible fuel in the cement clinker burning step of using wood pulverized material and plastic pulverized product as a supplemental fuel.
[0002]
In recent years, due to various regulations on waste has been reinforced, plastic, for respect to the combustible waste such as wood and the like dioxin problem, the process of a general incinerator is becoming difficult there. Under such circumstances, in order to shift to a recycling society, the opportunity to use these combustible wastes as cement clinker production for fuel has increased.
A method of using plastic waste as clinker firing fuel as an alternative to the pulverized coal is generally used as a cement clinker manufacturing fuel, various techniques have been disclosed.
For example, Patent Document 1, blow plastic waste from a nozzle provided in front kiln kiln, ultimately oxidized clinker burning step by land burned on clinker allowed to reach kiln inlet part as possible in the kiln to perform in an atmosphere, a method of manufacturing so as not to impair the quality of the clinker is disclosed.
Further, Patent Documents 2 and 3, the plastic waste is pulverized, then the air combustion by adjusting the rate discharged from the kiln kiln before the nozzle, clinker method to not be fired in a reducing atmosphere is disclosed.
[0003]
[Patent Document 1]
Japanese Patent No. 2905689 (claim 1, Fig. 1)
[Patent Document 2]
JP 2000-169197 JP (claim 1)
[Patent Document 3]
JP 2001-206746 JP (claim 1)
[0004]
[Problems that the Invention is to Solve
Patent Documents 1 to 3 mentioned above, although description about the plastic waste, is not mentioned in connection with specific combustion method of the wood waste. For example, the present inventors have, wood waste was ground to a particle size of Patent Document 3, when the blow clinker fired in large quantities as an auxiliary fuel before kiln kiln, the combustion gas temperature compared to when using pulverized coal alone There was lowered, a problem that firing of the clinker can not be performed sufficiently occurs.
On the other hand, for the plastic waste, triturated with granularity of Patent Document 3, when the blow clinker fired in large quantities as an auxiliary fuel before kiln kiln, different concerns than wood waste is generated. That is, compared with the case of firing in pulverized coal alone, the combustion gas temperature rises and therefore, damage to the Kirunrenga occurs. Further, since the quality variation due to lots of plastic waste difference is large, a problem that it is difficult to control the sintering temperature becomes large fluctuation of the combustion gas temperature occurs.
The present invention, the problems in place of the pulverized coal occur when using a flammable waste such as wood or plastics as an auxiliary fuel, i.e., increase the combustion gas temperature, a decrease or fluctuation suppressing, furthermore, Kirunrenga damage to an object of the invention to provide a preventing combustion improving methods.
[0005]
Means for Solving the Problems The present inventors found that a method of using a combination of those located within a certain range net calorific value of the main fuel and auxiliary fuel, a method which solves the problems the heading and have completed the present invention.
Namely, the present invention is the true calorific value of the pulverized coal 5000~8000kcal / kg as the main fuel, the true calorific value of wood pulverized and net calorific value of 2500~5000kcal / kg of 5000~13000kcal / kg plastic pulverized product was used as an auxiliary fuel, the fine coal, wood pulverized product per unit time of the plastic pulverized fuel consumption respectively X, when the Y and Z (either tons / hours), each of relationship, Y + Z ≦ X and characterized in that it is a 0.7 ≦ Y / Z ≦ 2.2, it relates to a combustion improving method of combustible fuel.
[0007]
DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail below. Incidentally, this embodiment is intended to explain the purpose of the invention better specifically in order to understand, unless otherwise specified, it is not intended to specify the invention contents.
[0008] In the present invention, a pulverized coal main fuel, firing the cement raw material formulation in a rotary kiln wood pulverized material and plastic pulverized product as a supplemental fuel, to obtain cement clinker.
Pulverized coal is the main fuel is not particularly limited as long as it generally coal pulverized material used for cement clinker firing.
Crushed wood was used for the auxiliary fuel, and timber of forests, wood processing chips generated by wood processing companies, wood chips, and wood crushed with such a grinding wood chips generated at a building site, if wood, its types of cedar, cypress, pine, beech, red cedar, Douglas fir, hemlock, lauan, Ezo pine, such as sea lions pine, may be any of those.
Further, the plastic ground material is crushed such as polyethylene, polypropylene, polystyrene, regardless raw material species if pulverized solid resin.
[0009] net calorific value of the fuel is intended to be measured in accordance with JIS M 8814 "calorific value measuring method of the coal and coke", in general, also referred to as lower heating value or lower heating value.
For example, pulverized coal is the main fuel is the calorific value uses those 5000~8000kcal / kg, preferably using those of 6000~7000kcal / kg. Crushed wood material is the heat value to use those 2500~5000kcal / kg, preferably using those of 3000~4000kcal / kg. Furthermore, the plastic ground material is the amount of heat generated using those 5000~13000kcal / kg, preferably using those of 7000~12000kcal / kg.
When the heat generation amount exceeds the range of net calorific value, for the pulverized coal, because it is the main fuel combustion gas temperature, they have a tremendous negative effect on the ignitability, wood pulverized product, with respect to the plastic ground material, the combustion gas temperature, adversely affect the combustion stability.
[0010] The amount of these fuels, each of the fuel consumption per unit time, the pulverized coal X (tonnes / hour), a crushed wood product Y (tons / hour), the plastic ground material Z ( If the tons / hour), each relationship, Y + Z ≦ X, and is preferably 0.7 ≦ Y / Z ≦ 2.2. These relationships are based on experimental data, showing the division of the proper area in approximation.
X <In the region of Y + Z, the frame forming a combustion gas compared with the case of pulverized coal alone is insufficient. Moreover, the larger variation in combustion gas temperature.
Further, the Y / Z <0.7, too combustion gas temperature rises, the 2.2 <Y / Z, the combustion gas temperature is too low reversed.
These expressions reasons associated with the combustion gas temperature is not clear is presumed to be due to the following reasons.
That is, when the combustion rate of the fuel is assumed to equal, when compared with the true calorific value, it is in the timber <pulverized coal <plastic relation, also, a comparison of amount of gas generated during combustion, wood <pulverized coal < relation that plastic, furthermore, the generated gas amount per net calorific value has been speculated that it is due to the fact that a relationship of plastic <pulverized coal <wood. That combustion, the amount of gas generated per net calorific value, determines the actual combustion gas maximum temperature approximately is, smaller the value, considered to combustion gas temperature becomes higher, therefore, by combining different fuels of these characteristics well it is the main object of the present invention to improve the properties.
[0011] The shape of crushed wood material and plastic pulverized product, it is necessary that the pulverized coal and the burning rate is adjusted to be the same. The shape of pulverized material, length, width, but is specified by three length of the thickness, and especially the length in the thickness direction indicating the minimum length affects the combustion speed. Specifically, it is preferable that the average length in the thickness direction is the shortest direction of pulverized material is 0.2 to 2.0 mm. When the average length in the thickness direction is more than 2.0 mm, the combustion speed is slower, there is a possibility that unburnt matter occurs. Further, it is less than 0.2 mm, compared with the case of pulverized coal alone combustion, not only burn rate too fast, it is necessary to excessive energy milling.
The measurement of the average length in the thickness direction, when the pulverized product was sieved with standard mesh sieve of 9.52mm specified in JIS Z 8801, a sieve passage component when the sieve passing fraction was ground to 90% It was a measurement sample of which measures the length of the thickness direction of about arbitrarily extracted sample 100 points, determined by simple average.
[0012] In the following, a specific example with respect to the combustion process of combustible fuel in the cement clinker production process, a more detailed description of the present invention.
Figure 1 is an example of a cement kiln which is generally used, first with reference to this figure, illustrating the cement clinker burning step.
Cement material is fed from the uppermost entrance 3a of the cyclone 3b of the suspension preheater, while gas and heat exchange is discharged from the lower stage calcining furnace 3c, and supplied to the kiln 1 through the inlet hood 3e. Cement raw materials, to move inside the kiln from the kiln inlet 5 to the kiln before 4, sintering proceeds while further subjected to heat exchange. Calcined clinker is quenched with 2 of clinker cooler.
[0013] via the rotary valve 10a pulverized coal main fuel from the main fuel hopper 9a, together with the compressed air in the compressor 11a, it is blown from the main fuel burners 7a, burns to form a frame 8 within kiln 1. Crushed wood product and plastic pulverized product, respectively, hopper 9b, the rotary valve 10b from 9c, via 10c, a compressor 11b, 11c together with the compressed air, is provided over the main fuel burners 7a auxiliary fuel blowing port 7b, blown into the kiln from 7c, burning by exposure to a high temperature atmosphere in the kiln. These auxiliary fuel, rather than forming a distinct frame, or burned in a form that is incorporated into the frame 8 of the main fuel, or ignited every burning particles suspended combustion of the kiln.
Therefore, the auxiliary fuel blowing port 7b, 7c may be provided over the upper portion of the main fuel burners 7a, it may be blown using two blowing port, but the auxiliary fuel blowing port and one, from there, it may be blown mixtures of crushed wood material and plastic pulverized product.
[0014] Wood pulverized and plastic pulverized pulverized coal and the auxiliary fuel of the main fuel, autosampler 12a, 12b, periodically withdrawn at 12c, to measure the net calorific value. Further, the combustion gas temperature in the kiln is measured in the far thermometer 13 provided in the auxiliary fuel burner top.
[0015]
EXAMPLES cedar as wood pulverized, as the plastic pulverized product was used after pulverized polypropylene as auxiliary fuel, an example in the case of performing calcination of the cement clinker.
Table 1 shows the characteristics of the pulverized coal and wood pulverized and plastic ground material used in the main fuel and auxiliary fuel. These properties, JIS M 8812 "coals and coke industry analysis", JIS M 8813 "coals and coke elemental analysis", and were analyzed according to JIS M 8814 "coals and coke calorific value measuring method" it is the result.
Using these fuels, it was fired cement clinker in the manner described above. The results are shown in Table 2. Incidentally, the combustion gas temperature measurements in the kiln was used far thermometer (Yokogawa M & C (KK) PM173).
[0016]
As described above, according to the present invention, according to the present invention, when firing the cement material in the rotary kiln, a pulverized coal as a main fuel, using a wood pulverized material and plastic pulverized product as a supplemental fuel, their determine the amount per unit time, the combustion characteristics of the kiln was improved by skillfully combining different fuels of these burn characteristics, increase the combustion gas temperature, decrease, or prevent variation, also prevent damage to the Kirunrenga, more it is possible to produce a stable clinker quality.
[0017]
[Table 1]
[0018]
[Table 2]

BRIEF DESCRIPTION OF THE DRAWINGS
1 is a diagram showing a structure of a cement clinker sintering apparatus in which the method is implemented in the present invention.
DESCRIPTION OF SYMBOLS
1 kiln 2 cooler 3 suspension preheater 3a SP fan uppermost inlet 3b cyclone 3c calciner 3d rising duct 3e inlet Hood 4 kiln before 5 kiln inlet 6 SP fan 7a main fuel burners 7b, the 7c auxiliary fuel blowing port 8 main fuel burner frame 9a main fuel hopper 9b, 9c auxiliary fuel hopper 10a main fuel for rotary valves 10b, 10c auxiliary fuel for rotary valves 11a main fuel compressors 11b, 11c auxiliary fuel compressors 12a main fuel autosampler 12b, 12c auxiliary autosampler for fuel

Claims (3)

1. Net calorific value is a pulverized coal 5000~8000kcal / kg as the main fuel, wood pulverized and net calorific value of the true calorific value 2500~5000kcal / kg is used plastic pulverized 5000~13000kcal / kg as auxiliary fuel , fine coal, wood pulverized product, when the fuel consumption per unit of plastic ground material time each X, and Y and Z (either tons / hours), each relationship, Y + Z ≦ X and, characterized in that it is a 0.7 ≦ Y / Z ≦ 2.2, combustion improving method of combustible fuel in the cement clinker burning step.
2. Wherein the average length in the thickness direction of the wood crushed product and the plastic granulated material is 0.2 to 2.0 mm, a combustion improving method of the combustible fuel in cement clinker firing process according to claim 1.
3. An auxiliary fuel inlet tube provided in the upper portion of the pulverized coal combustion burner, and supplying the crushed wood material and plastic pulverized product, the combustion of the combustible fuel in cement clinker firing process according to claim 1 or 2 sex improved method.

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