JPS60203A - Method of utilizing solid fuel in powdery dust firing apparatus - Google Patents

Abstract

PURPOSE:To efficiently utilize the fuel and to improve the dust collection efficiency by preliminarily burning the soild fuel containing volatile components in order to remove the volatile components in such a preliminary burning. CONSTITUTION:The powdery solid fuel containing volatile components is blown into a boiler 15 to be burnt by a burner 14 therein, an the volatile components contained in the solid fuel are completely burnt in this stage. The calorie of the preliminary burning of the solid fuel is effectively utilized in that it is used for the operation of a turbine generator 16. Then, an electrical dust collector 11 collects a mixture of the unburnt solid fuel introduced from the boiler 15 and scattering dust introduced from a rotary kiln 7. The unburnt solid fuel contained in such dust mixture is completely burnt in a raw material pre-heater 8 and the rotary kiln 7 in which the burning takes place by a burner 12. In this manner, the fuel is effectively utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for firing powder or granular materials such as a cement firing kiln or a quicklime firing kiln.

After pre-combusting the solid fuel containing volatile matter to burn off the volatile matter, it is collected by mixing with the dust discharged from the powder and granular material kiln, and mixed with the raw materials to be fired and sent to the powder and granule material kiln. The present invention relates to a method of using fuel in a powder and granular material sintering apparatus, which is characterized by complete combustion.

Generally, various methods have been devised to reduce energy consumption in apparatuses for firing granular materials, such as cement firing kilns and quicklime firing kilns.

One method is to mix flammable substances into the raw materials to be fired and use the combustion heat of the combustible substances in the firing process to reduce fuel consumption and stabilize the firing reaction. It is being said. However, if the combustible substances mixed into the raw material contain volatile matter, most of the volatile matter will volatilize during the preheating and temperature raising process of the raw material, and will not be effectively utilized and will go out of the system. It will be wasted.

Therefore, an object of the present invention is to eliminate such conventional waste of fuel and to plan for effective utilization of the fuel by pre-combusting a solid fuel containing volatile matter to remove the volatile matter and then using a granular material sintering apparatus. It is an object of the present invention to provide a method for using solid fuel in a powder or granular material sintering apparatus, which is characterized in that solid fuel is introduced into the raw material to be sintered and completely combusted.

Other objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

First, FIG. 1 of the drawings schematically shows an example of the process of a conventional cement kiln. In such a conventional cement firing kiln, the raw material supplied from the feeder is mixed with flammable substances supplied from the feeder, and the mixture passes through the weighing machine 6 and then goes to the left of another weighing machine. The collected dust that has passed through is mixed and sent to the upper part of the raw material preheater. Next, such raw materials undergo preheating and decarboxylation processes and are fired in the rotary kiln 7 to become tarinka, which is discharged from the end of the rotary kiln 7. Combustible substances mixed in the raw materials exchange heat with the hot gas discharged from the kiln in the raw material preheater zone in a countercurrent manner, raise the temperature, and finally burn to heat the raw materials and contribute to the firing reaction. However, when the volatile substances contained in the combustible substances are sent to the raw material preheater S, they come into contact with the hot gas of 3kOC-1100c, and after that, the temperature gradually increases while flowing down the raw material preheater G. It evaporates with the exhaust gas and is passed through a ventilator9. The heat is introduced into the electrostatic precipitator // via the raw material dryer 10 and is discharged from the stack 13 to the outside of the system, so that its amount of heat is not used effectively. The mixed dust collected by the electrostatic precipitator/l is stored in a dust silo by a transporter 3, and then sent to a raw material preheater g via a weigher 3.

An example of implementing the method of the present invention for solving the above-mentioned problems in the conventional method is shown in FIG. 2 for a cement firing kiln.

First, powdered solid fuel containing volatile matter is transferred to a boiler i! by a burner/ll. The solid fuel is blown into the solid fuel and combusted, and all volatile components contained in the solid fuel are burned out at this stage. The amount of heat generated by this pre-combustion of solid fuel is, for example, a turbine generator/6
It is used for driving and is put to effective use. Next, a part of the combustible solid content and ash of the solid fuel are transferred to boiler/3 as unburned content.
It is also discharged and introduced into an electrostatic precipitator. Since the unburned solid fuel discharged from the boiler 13 is mainly composed of carbon, its specific electrical resistance is less than 104 Ω, which causes a re-scattering phenomenon in the electrostatic precipitator, and only this is collected. If it gets dusty, the dust collection effect will be reduced. However, combustion gas containing scattered dust discharged from the cement kiln, that is, the rotary kiln 7 and the raw material preheater by the ventilator, is introduced into the electrostatic precipitator via the raw material dryer 10. The unburned solid fuel introduced into the rotary kiln 7 and the scattered dust introduced from the rotary kiln 7 are collected in a mixed state.

In this way, by collecting a mixture of high electrical resistance cement firing kiln dust and low resistance boiler dust, the specific resistance of the mixed dust is 105 to 10, which is suitable for electrostatic precipitation.
'. Since it is within the range of Ω-On&, there is no need to strictly control the exhaust gas temperature introduced from the rotary kiln 7 for cement formation to the electrostatic precipitator //, and the dust collection rate is improved, so the dust collection is It is possible to increase the amount of processing gas per liter per machine.

The mixed dust collected by the electrostatic precipitator // is then stored in the dust siloder by the transporter 3, mixed with the raw material at a fixed ratio via the weigher j, and sent to the raw material preheater g. be done.

Since the unburned solid fuel contained in this mixed dust does not contain any volatile matter, it is completely combusted in the raw material preheater g and the rotary kiln 7, where combustion is performed by the burner 2, and is effectively utilized for the calcination reaction. As mentioned above, the volatile content of the solid fuel is completely combusted in the boiler/S, and the unburned solids are transferred to the rotary kiln 7 for firing cement.
Since the solid fuel is used effectively, there is no wastage of fuel, and the amount of unburned content in the boiler is not a problem for the entire plant.In fact, the fineness of the solid fuel is made slightly coarser and a large amount of unburned content is recovered to be used for cement firing. By supplying the powder to the rotary kiln 7 together with the raw material powder, the amount of fuel used in the cement firing system is reduced, and the stable operation of the firing process is ensured, which is advantageous for the system as a whole.

Table 1 below shows an example of the properties of oil coke used as boiler-injected solid fuel. An example is shown in the table below.

As explained above, the present invention is to provide a combustion device such as a boiler that pre-combusts solid fuel containing volatile matter in a firing device for granular materials such as cement to remove volatile matter in advance by combustion. This is extremely effective in making effective use of fuel and improving the dust collection rate. Of course, such a volatile combustion system may be a heat utilization device other than a boiler, and the cement kiln may have an auxiliary combustion furnace in the raw material preheating mechanism, or it may be a cement kiln method that does not have a preheating mechanism. Alternatively, a quicklime kiln or other powder kiln may be used.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the steps of a conventional cement firing kiln, and FIG. 2 is a schematic diagram showing the steps of a cement firing kiln implementing the method of the present invention. In the figure, /, Coni feeder, 3: Transport machine, q: Dust silo, S, t,: Weighing machine, 7: Rotary kiln, g: Raw material preheater, 9 = Ventilator, IO = Raw material dryer, l/: Electric collector Dust machine, /2. /'1: burner, 13: boiler, 11
．． : Turbine generator. Patent applicant Onoda Cement Co., Ltd.

Claims (1)

[Claims] A powder characterized in that after pre-combusting solid fuel containing volatile matter to remove volatile matter, the powder is introduced into a granular material sintering device, mixed with raw materials to be sintered, and completely combusted in the granular material sintering device. Method of using solid fuel in granular firing equipment.