JPS63151650A - Method of burning cement clinker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cement clinker firing method that uses waste such as municipal garbage as part or all of the fuel for cement clinker firing.

<Prior art and its problems> FIG. 2 is a flowchart for explaining a typical example of a conventional cement clinker firing device, in which arrows indicate gas flows. The firing device basically includes a preheating device 1, a rotary kiln 2, and a clinker cooler 3.

In this configuration, the raw material input into the preheating device 1 is preheated, sent to the kiln 2 to be fired, and dropped into the cooler 3, where it is cooled by the cooling air introduced there and becomes a product clinker. A part of the cooling air is recovered as secondary air for combustion in the kiln 2, and the exhaust gas from the kiln 2 is discharged from the equipment after preheating the raw material in the preheating device 1.

In the case of equipment in which the preheating device 1 is equipped with a raw material calciner 1a, another part of the cooling air bypasses the kiln 2, passes through the secondary air duct 4, and is used for combustion in the calciner 1a. It is directly recovered to the preheating device 1 as secondary air/gas.

The exhaust gas discharged from the preheating device 1 is sucked from the exhaust gas duct 5 by the exhaust gas duct 6, and is further passed through the dust collector 7,
It is discharged into the atmosphere from the chimney 8 through the dust collector exhaust fan 7a. Cooling air other than that recovered as secondary air for combustion in a kiln or the like is discharged from the cooler 3 as surplus high-temperature air, and is passed through the exhaust duct 9 to the dust collector 10 and the exhaust fan 11.
It is then released into the atmosphere from the chimney 12. The exhaust gas discharged from the preheating device 1 is normally at a high temperature of about 350°C, so in order to utilize the residual heat, it is introduced into the drying device 13 to dry raw materials etc. before entering the dust collector 1. The waste heat is introduced into the waste heat boiler 14 to generate steam and generate electricity. Since power generation by the waste heat boiler 14 is more efficient as the inlet gas temperature increases, depending on the case, it may be installed at a position 14a in the middle of the exhaust gas duct 5 or at a position 14b parallel to the preheating device 1.

However, regarding the excess air discharged from cooler 3,
Even in normal conditions, the temperature changes within a range of about 150 to 250°C, and the amount also varies greatly, so it is relatively unstable and difficult to use residual heat. nevertheless,
Although it is sometimes used as an auxiliary drying heat source, the amount used is not very large and the surplus is released into the atmosphere after dust collection, but the dust contained here is difficult to compare. Moreover, it often causes problems because it easily adheres to and hardens on nearby objects. Also, recently,
Since energy conservation has become a strong priority, even such heat sources have been used for waste heat power generation, but introducing relatively low temperature gas means that equipment It also reduces efficiency and means that a sufficient effect cannot be expected from a large investment.

On the other hand, various problems have been raised regarding the treatment of waste such as municipal garbage. Landfill sites for various types of waste are becoming fewer and fewer, and the expansion of treatment facilities for these wastes has become an urgent issue.

These wastes are usually incinerated, and the waste heat generated is sometimes used to generate electricity to supplement electricity for equipment or contribute to local welfare in ways such as hot water supply. Not a few.

However, in either case, not only does the construction and operation and maintenance of these treatment facilities require a huge amount of money, but the construction of the facilities itself is difficult for the local community due to the problems of odor and environmental pollution caused by sewage. The reality is that the expansion of facilities is not progressing as expected, as the consent of residents has not been obtained.

<Purpose of the Invention> The present invention has been made in view of the above points, and aims to save energy, prevent environmental pollution, and reduce construction costs by organically combining cement tarinka firing equipment and waste processing equipment. It is an object of the present invention to provide a cement tarinka firing method that can achieve even the highest possible results.

Means for Solving the Problems In order to achieve the above object, the cement clinker firing method of the present invention stores waste such as municipal garbage in a drying device, and supplies part of the high-temperature air from a clinker cooler to the drying device. Introducing the
The exhaust gas is returned to the clinker cooler, and the high-temperature air from the clinker cooler mixed with the exhaust air from the drying device is used as combustion air for the rotary kiln or calciner.

Embodiment> An embodiment embodying the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart of an apparatus embodying the method of the invention. In Fig. 1, 1 is a preheating device, 1
a is a calcining furnace, 2 is a rotary kiln, 3 is a clinker cooler, 4 is a secondary air duct, 5 is an exhaust gas duct, 6 is an exhaust fan, 7 is a dust collector, 7a is an exhaust fan for the dust collector, 8 is a chimney ,
9 is an exhaust duct, 9a is a branch exhaust duct, 10 is a dust collector, 11 is an exhaust fan for the dust collector, 12 is a chimney, 13 is a drying device, 14 is a waste heat boiler, 15 is a waste dryer, 16
17 is a dust collector, 17 is an exhaust fan, and 18 is an exhaust duct.

Figure 1 shows the conventional cement clinker firing equipment shown in Figure 2 with a waste dryer 15 added, and other parts are the same as Figure 2, so the same parts are designated by the same reference numerals. The newly added parts in FIG. 1 will be explained below, and the explanation will be omitted.

The waste dryer 15 is of a type such as a rotary set or a grade type, and it dries wet waste by bringing the waste into direct contact with hot air. The exhaust fan 17 sucks the hot air used for drying the waste and returns it to the clinker cooler 3 through the exhaust duct 18. The dust collector 16 is an exhaust
It is provided to prevent foreign matter from entering l17.

The action will be explained below.

With the above configuration, a part of the excess high temperature air of the cooler 3 flows into the dryer 15 from the branch duct 9a and is used for drying the waste. Since the exhaust gas after drying the waste has a strong odor, it is necessary to deodorize it. This exhaust gas can be deodorized by heating it to about 700°C or higher. Therefore, this air is recovered and used as combustion air for the kiln 2, etc., to deodorize it. However, normally, this exhaust temperature (100 to 150°C) is too low to directly introduce it into the kiln 2, etc., so the dust collector 16,
Cooler 3 via exhaust fan 17 and exhaust duct 18
is introduced as cooling air. Room-temperature air is usually introduced as cooling air, so in that sense the temperature is high, but even with conventional methods, surplus exhaust gas at a similar temperature can be circulated and used to improve heat recovery efficiency. There are some cases where people are trying to do so, so this is not a particular problem. Roughly speaking, the amount of excess exhaust gas is usually about 1:1 to 1.2 (although it may be about 1.5 times the amount of combustion air), so almost all of it is recovered and used. can do.

Incidentally, the dried waste discharged from the dryer 15 is used as fuel for the kiln 2 and the calciner 1a in the preheating device 1 after separating incombustible materials as necessary and pulverizing it appropriately. Ru.

The method of recovering the exhaust gas from the dryer 15 is not limited to the above, and for example, it can be used as temporary air for the kiln 2 or mixed into the secondary air of the calciner. Additionally, if the waste contains a lot of water and the excess air does not have enough heat, there are other methods such as using preheater exhaust gas or auxiliary combustion. Incidentally, if it is necessary to prevent the generation of odor when the equipment is not in operation, a deodorizing material or the like may be provided in the exhaust duct 18 for use in evacuation.

<Effects of the Invention> The effects of the present invention described above can be summarized as follows.

(1) A double energy-saving effect can be obtained by drying waste by utilizing the surplus heat that was conventionally dissipated into the atmosphere and reusing the recovered resources as fuel.

■ Remaining heat can be recovered without using complicated equipment that requires legal inspection, unlike waste heat boilers.

■ The environment in which deodorization and dust collection can be carried out relatively easily is technically in place.

(4) Construction costs can be drastically reduced because cement firing equipment and waste treatment facilities complement each other and double investment is avoided.

■ If there is idle equipment in a cement plant due to rationalization or production adjustment, most of that equipment can be effectively recycled and used, which can further reduce construction costs, but it is not enough to do so alone. In addition, it is expected that it will be possible to easily solve problems related to the location of waste treatment facilities.

(ω) Since redundant deployment of personnel and equipment is avoided, personnel costs and operation and maintenance costs such as equipment maintenance and inspection can be significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a flowchart 1 of an embodiment of the present invention, and Fig. 2 is a flowchart of a conventional cement tarinka firing apparatus...Preheating device 2...Rotary kiln 3・・・・・・Clinker cooler

Claims (1)

[Claims] Waste such as municipal garbage is stored in a drying device, a part of the high-temperature air from the clinker cooler is introduced into the drying device, and the exhaust air is returned to the clinker cooler, and the clinker cooler mixed with the exhaust air from the drying device is A clinker cooler firing method characterized in that high-temperature air is used as combustion air in a rotary kiln or calciner.