JPS5857381B2 - Cement firing equipment including calcining furnace for cement raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cement firing apparatus including a calcination furnace for cement raw materials.

The rotary kiln with a raw material preheater has been improved, and a calcination furnace with an independent heat source has been installed between the raw material preheater and the rotary kiln, and the raw material that requires the most amount of heat can be calcined using the rotary kiln with a raw material preheater. Cement firing equipment, which uses a calcining furnace with high heat transfer efficiency instead of a rotary kiln with low heat transfer efficiency to reduce the size of the equipment and various basic units, is widely known and has already become very effective. Many inventions have been made.

Some of these devices have already been put into practical use.

The preheater used in such cement firing equipment may be a cyclone only, or a so-called co-current preheater or counter-current preheater that combines several stages of cyclones and vortex chambers, but cement using the former Most of the equipment is baking equipment.

In addition, various kinds of cement firing apparatuses are characterized by the type of calcining furnace, and these calcining furnaces can be classified according to the type of airflow used and their structure.

That is, they are divided into those that utilize swirling flow, those that utilize a spouted bed, those that utilize a spouted bed and swirling flow, and those that utilize a fluidized bed.

Cement firing using these cement firing devices can be expected to have at least the benefits of using a kiln with a raw material preheater, but furthermore, as rotary kilns are smaller and the heat load inside the kiln is reduced, equipment costs can be reduced. Reduction of firebrick basic unit, pollution component nitrogen oxide (NO)
Various benefits such as a reduction in the amount of X) generated can also be expected.

However, the following various drawbacks are still found in these cement firing devices or the raw material preheaters or calcining furnaces that constitute them.

(r) In general, in calciners, especially in calciners other than the fluidized bed type, the residence time of the raw fuel is short, so the fuel does not burn completely in the furnace. Combustion continues in the second or higher cyclones counting from the lowest stage, causing coaching trouble in those cyclones or in the conduit between the cyclones, or increasing the temperature of the gas discharged from the top cyclone. It increases the heat removed from the exhaust heat gas of the cement firing equipment.

The amount of increase in heat removed is equal to or may be greater than the amount of reduction in heat consumption due to kiln miniaturization using this method.

Such problems are particularly serious when using solid fuels such as coal, and often make the use of solid fuels almost impossible.

This is because the combustion time of solid fuel is longer than that of liquid fuel.

(2) These cement firing devices usually include a rotary kiln, a so-called co-current preheater that combines several stages of cyclones or vortex chambers, and a calciner that suspends raw materials in an air stream and performs calcining using the heat of fuel combustion. and a cyclone that separates the raw material from the calciner exhaust gas accompanied by the calcined raw material.

Therefore, the pressure loss of the entire cement firing device is the sum of the pressure losses of these individual devices.

Preheaters require fairly high pressure drops.

In addition, many calcining furnaces are of the type that disperses the raw material in an upward air current and calcinates it while lifting it. The gas flow rate must be increased considerably, which not only reduces the calcination time and fuel combustion time in the calcination furnace, but also increases the pressure drop, as described above.

In addition, the pressure loss of the cyclone for separating the calcined raw materials is added, and the overall pressure loss becomes quite high.

In addition, in many of these cement firing devices, the same induction fan is used to induce the kiln exhaust gas and the clinker cooler bleed gas for combustion in the calciner, and in this case, the pressure of both gases cannot be balanced. One or both of these are usually adjusted using dampers, apertures, etc.

However, using a damper or throttle to balance the pressure ends up increasing the pressure loss.

Therefore, the pressure drop in the cement kiln is further increased, and therefore the power used in the exhaust gas induction fan is considerably higher, and the overall power consumption of the kiln is reduced, despite the benefits of reducing drive power by downsizing the kiln. It is not necessarily less than a kiln with a raw material preheater.

Note that when a fluidized bed furnace is used as the calcining furnace, the pressure loss is particularly high, and the amount of electricity used is also increased.

Furthermore, even in the case of the most commonly used type of calciner, which combines a spouted bed and a vortex chamber, the introduction of swirling flow gas into the inverted conical part used to form the spouted bed causes unnecessary Aggregation of raw material particles and stagnation phenomena are observed, resulting in a decrease in air density, combustibility, and heat transfer in that area, as well as an increase in pressure loss.

3) Cement raw materials contain some alkali and chlorine, but these components volatilize and condense in the circulating dust between the kiln and the calciner or between the calciner and the co-current preheater. It is concentrated by the action of

When these components increase, the melting point of the dust decreases, and the dust adheres to the dust between the kiln and the calcination furnace or between the cyclone of the preheater, causing coaching problems and lowering the draft, resulting in inoperability. It may become.

Therefore, the content of alkali and chlorine in the raw materials used is limited.

4) When a countercurrent preheater is used as a raw material preheater for such a cement firing device, various benefits such as improved heat transfer efficiency, reduced pressure loss, and elimination of coating troubles can be expected.

However, in conventional countercurrent preheaters, the dispersibility of raw materials is not always good, and ideal heat exchange is not always performed.

For example, high-temperature gas is introduced from the bottom as a swirling flow and raised, the raw material is introduced from the top using a dispersion cone, and the raw material is dispersed in the gas by the action of the dispersion cone and the rising swirling flow, and the gas and raw material are separated. An upright cylinder counterflow preheater is known that exchanges heat in a countercurrent manner, but even in this case, ideal material dispersion is not always achieved, and the swirling flow of high-temperature gas from the bottom reaches the top. There is a risk that the upper part will simply be an updraft, and the center in particular will be in a state where high-temperature gas blows through, reducing the chance of contact between the raw material and the gas.
Furthermore, when feeding raw materials to the top of an upright cylinder, using only a dispersion cone may result in poor dispersion of the raw materials, and the raw materials within the upright cylinder may become temporarily uneven and may fall instead of being dispersed, which is not always ideal. Countercurrent heat exchange is not taking place.

Improving the dispersion of the raw material within this upright cylinder is necessary in order to improve the heat transfer characteristics of the countercurrent preheater and to make it possible to manufacture and operate a larger countercurrent preheater.

This invention relates to a cement firing device that improves the drawbacks of the prior art in the upper part. An upper chamber and a lower chamber are provided by a throttle, and kiln exhaust gas and high temperature air extracted from a clinker cooler are tangentially directed into each chamber. The two-stage cyclone type calcining furnace to be introduced is combined with an upright cylinder counterflow type preheater that swirls the calciner exhaust gas upward from the bottom and feeds raw materials from the top. In addition, in order to improve the dispersion of raw materials, a relatively small amount of calciner exhaust heat gas or clinker cooler bleed air is introduced in a swirling manner into the central part, not only when liquid fuel is used, but also when solid fuel is used. The fuel is completely combusted in the calcination furnace and the lower part of the countercurrent preheater, and ideal countercurrent heat exchange is performed, which lowers the temperature of the gas discharged from the preheater and improves the calcination rate of raw sashimi entering the rotary kiln. almost 10001
0, reducing fuel consumption, the overall pressure loss is very low, the pressures of the rotary kiln exhaust gas system and clinker cooler extraction system are balanced, and the nitrogen oxide emissions are very low. The purpose of this project is to provide a cement firing device that can perform

Next, a cement firing apparatus including a cement raw material calcining furnace of the present invention will be described with reference to drawings showing embodiments.

Reference numeral 1 is an exhaust fan for all exhaust gas flow, 2 is a cyclone, 3 is an exhaust gas conduit, 4 is a countercurrent preheater, 9 is a calciner, 15 is a rock kiln, and 17 is a clinker cooler.

The countercurrent preheater 4 includes a cylindrical, rigid main body 4a, and an inverted conical raw material discharge chamber 4b formed at the bottom of the main body 4a.

The lower part of the main body 4a is connected to the calciner 9 via the calciner exhaust gas conduit 7.
It communicates with the upper chamber (described next).

As shown in FIG. 2, the calciner exhaust gas conduit 7 is connected tangentially to the main body 4a.

Further, the raw material discharge chamber 4b is communicated with a kiln exhaust gas supply pipe, which will be described below, via a raw material discharge pipe 18.

The upper end of the countercurrent step heater 4 is connected via the exhaust gas conduit 3 to the inlet pipes 3a of a plurality of cyclones 2 installed around the exhaust gas conduit 3.

The lower end of the cyclone 2 is connected to a countercurrent preheater 4 via a conduit 2a.
It communicates with the upper part of the main body 4a.

The upper end of the cyclone 2 is connected to the suction side of the exhaust fan 1 via an exhaust gas discharge pipe 19.

5 is a dispersion cone for uniformly dispersing the raw material within the main body 4a, and 6 is a raw material supply pipe.

The calcining furnace 9 is composed of two chambers, upper and lower.
a. The lower part is defined as a lower chamber 9b, and a constricted part 9c is provided between the upper chamber 9a and the lower chamber 9b.

A combustion air introduction pipe 12 connects the clinker cooler and the calciner 9, and is connected to the upper chamber 9a by an upper branch pipe 12a and to the lower chamber 9b by a lower branch pipe 12b.

Upper and lower branch pipes 12a of the combustion air introduction pipe 12.

12b is the upper chamber 9a as shown in FIGS. 3 and 4.
Alternatively, they are each tangentially communicated with the lower chamber 9b.

21 and 22 are dampers provided in the upper branch chamber 12a or the lower branch chamber 12b of the combustion air introduction pipe 12.

13 is the exhaust gas discharge side of the rotary kiln 15 and the calcining furnace 9
The upper chamber 9a is connected to the upper branch pipe 13a, and the lower chamber 9b is connected to the lower branch pipe 13b.

Upper and lower branch pipes 13a of the kiln exhaust gas supply pipe 13.

13b is tangentially connected to the upper chamber 9a or the lower chamber 9b, respectively, as shown in FIGS. 3 and 4.

23.24 is the upper branch chamber 13 of the kiln exhaust gas supply pipe 13
af is a damper provided in the lower branch chamber 13b.

Reference numeral 18 denotes a raw material feed pipe for feeding cement raw material into the kiln exhaust gas supply pipe 13 from the lower end of the raw material discharge chamber 4b of the countercurrent preheater 4.

Reference numeral 25 denotes a raw material introduction pipe for introducing cement raw material from the lower end of the lower chamber 9b of the calcining furnace 9 to the raw material receiving side of the rotary kiln 15.

Reference numeral 26 denotes a raw material dispersion airflow introduction pipe that communicates the upper branch pipe 12a of the combustion air introduction pipe 12 with the upper part of the main body 4a of the countercurrent preheater 4.

Moreover, 27 is a raw material dispersion airflow branch pipe that connects the raw material dispersion airflow introduction pipe 26 and the calciner exhaust gas conduit 7.

28 is a damper provided on the raw material dispersion air flow introduction pipe 26, and 29 is a damper provided on the raw material dispersion air flow branch pipe 27.

10a is a burner provided in the upper chamber 9a of the calcining furnace 9;
0b is a burner provided in the lower chamber 9b of the calcining furnace 9, and 16 is a burner provided in the rotary kiln 15.

Since the cement firing apparatus of the present invention is configured as described above, the following operations can be performed.

A part or all of the cement raw material is supplied from a feeder (not shown) into the exhaust gas conduit 3 through a raw material supply pipe 6.

The cement raw material dispersed in the exhaust gas conduit 3 is heated (cocurrent heat exchange) by the exhaust gas discharged from the countercurrent preheater 4, and is passed through the inlet pipe 3a together with the exhaust gas by the exhaust fan 1. After that, it is sucked into the cyclone 2.

The waste heat gas containing the cement raw material is separated into the cement raw material and the waste heat gas in the cyclone 2, and the separated cement raw material is supplied to the upper part of the countercurrent preheater 4 through the conduit 2a.

During this time, in order to disperse the raw materials in the counter-current preheater 4, an air purge air introduction hole 8 is provided at the lower part of the cone of the cyclone 2 through which atmospheric air for air purge, clinker cooler bleed air, or auxiliary combustion exhaust gas can be introduced. .

The cement raw material supplied into the countercurrent preheater 4 is heated to the main body by the action of the dispersion cone 5, the gas swirl flow supplied from the raw material dispersion air flow introduction pipe 26, and the ascending gas swirl flow supplied from the calciner exhaust gas conduit 7. It is uniformly distributed throughout 4a.

Then, when the cement raw material descends through the main body 4a of the countercurrent preheater 4, it is heated countercurrently with the exhaust heat gas that is induced to rise inside the main body 4a through the calciner exhaust gas conduit 7, and is heated to the extent that a portion of the cement raw material is calcined. undergo heat treatment.

Thereafter, the cement raw material is separated from the exhaust gas by centrifugal force, discharged from the raw material discharge chamber 4b through the raw material discharge pipe 18, and supplied into the kiln exhaust gas supply pipe 13.

The cement raw material supplied to the kiln exhaust gas supply pipe 13 is
It is dispersed in the exhaust gas stream discharged from the rotary kiln 15, and immediately absorbs the heat of the high temperature exhaust gas to increase the calcining rate of the raw material and lower the exhaust gas temperature by soo°c'i. Together with the exhaust gas, it becomes a swirling flow, and one part flows into the lower chamber 9b of the calciner 9 through the lower branch pipe 13b, and the remaining part flows into the upper chamber 9a through the upper branch pipe 13a.

On the other hand, high-temperature air for combustion is also introduced into the upper chamber 9a and lower chamber 9b of the calciner 9 as a swirling flow from the clinker cooler 17 via the upper branch pipe 12a and the lower branch pipe 12b of the combustion air introduction pipe 12. , these gases form a vortex layer.

Burners 10a and 10b burn fuel within this swirl bed, and the main part of the calcination of the cement raw material is distantly performed.

In the upper chamber 9a of the calciner 9, fuel combustion is carried out by high-temperature air introduced as a swirling flow from the clinker cooler 17 in the cone section and the connection section with the lower chamber 9b, where the raw material has a high density. It is heated, decarboxylated, and collected by the cyclone effect.

Furthermore, the cement raw material falls into the lower chamber 9b of the calcining furnace 9,
Together with the kiln exhaust heat gas and the cement raw material introduced into the lower chamber 9b, the cone is rotated down by the cyclone effect.

During this time, fuel combustion is carried out by the high temperature air bled from the clinker cooler 17, as in the upper chamber 9a, and the decarboxylation action progresses.

The cement raw material calcined by approximately 10% in the calciner 9 is supplied to the rotary kiln 15 via the raw material introduction pipe 25, and the final clinker firing is performed by burning fuel in the burner 16.

The clinker fired in the rotary kiln 15 is taken out, cooled in a clinker cooler 17, and sent to the next process.

On the other hand, to describe the flow of combustion gas, part of the kiln exhaust heat gas accompanied by cement raw materials and the clinker cooler 17
A part of the more extracted high-temperature air is introduced into the lower chamber 9b of the calciner 9 as a swirling flow through the lower branch 13b of the kiln exhaust gas supply pipe 13 and the lower branch 12b of the combustion air introduction pipe 12, respectively. , the fuel is combusted by a burner 10b provided there.

The combustion gas generated in the lower chamber 9b is supplied to the upper chamber via the throttle part 9c, and the remainder of the kiln exhaust gas accompanied by the cement raw material and a portion of the high temperature air are further stored in the upper chamber.
The kiln exhaust gas supply pipe 13 and the upper branches 13a and 12a of the combustion air introduction pipe 12 introduce the swirling flow, and a burner is provided to combust the fuel.

Note that the amount of kiln exhaust heat gas or high temperature air supplied to the upper chamber 9a and lower chamber 9b is determined by the damper 21, 22, 23.
, 24 can be adjusted.

By reducing the amount of high-temperature air introduced into the lower chamber 9b by operating the damper, the fuel is incompletely combusted and cyclic substances are generated, and while the combustion gas containing them moves to the upper chamber 9a, the kiln is heated. Nitrogen oxides in exhaust gas can be decomposed into ring elements.

All or most of the exhaust gas discharged from the upper chamber 9a of the calciner 9 is introduced into the lower part of the main body 4a of the countercurrent preheater 4 as a swirling flow via the calciner exhaust gas conduit 7. is,
It swirls upward within the main body 4a while exchanging heat countercurrently with the cement raw material.

Note that the unburned fuel in the calciner is completely combusted in the lower part of the main body 4a.

In addition, a relatively small amount of clinker cooler bleed air, calciner exhaust gas, or a mixture thereof is swirled and introduced into the upper part of the main body 4a of the countercurrent preheater 4 via the raw material dispersion air flow introduction pipes 26 and 27. The dispersion effect of raw materials is enhanced.

The exhaust gas that has swirled up the main body 4a of the countercurrent preheater 4 and the raw material dispersion gas are mixed, and are then heated from the top of the countercurrent preheater 4.
Via the exhaust gas pipe 3, the cyclone 2. and is discharged outside the system by the exhaust fan 1.

Since the cement firing apparatus including the cement raw material calcining furnace of the present invention is constructed as described above and operated as described above, it is possible to achieve the following effects.

(1) The calcining furnace 9 of the cement firing apparatus of the present invention has a two-stage cyclone type having an upper chamber 9a and a lower chamber 9b. The gas and the high-temperature air extracted from the clinker cooler 17 are introduced separately in the tangential direction, and burners 10a and 10b are installed near the high-temperature air inlet of the compartment to burn the fuel, so that the fuel is not supplied to the upper chamber 9a. While being calcined, the raw material swirls down the cone part due to the cyclone effect, passes through the intermediate constriction part 9c, enters the lower chamber 9b, and enters the lower chamber 9.
Together with the raw material supplied to b, the raw material is rotated down the cone part while being subjected to the calcination action again, and is separated.

On the other hand, the kiln exhaust heat gas and high-temperature air supplied to the lower chamber 9b swirl and rise while burning fuel, enter the upper chamber 9a through the intermediate constriction section 9c, rise through the cone section, and rise in the upper chamber 9a. The fuel is mixed with the kiln exhaust heat gas and high temperature air supplied to the kiln, and the reheated fuel is combusted.

Therefore, the cone portion of the upper chamber 9a and the intermediate constriction portion 9
Countercurrent heat exchange takes place where the raw material c is dense,
As heat exchange progresses under ideal conditions, the lower chamber 9
Efficient heat exchange also takes place in b.

Furthermore, the calciner 9 is composed of an upper chamber 9a and a lower chamber 9b, and the incompletely burned fuel in the lower chamber 9b can be re-burned in the upper chamber 9a by high-temperature air supplied there. Because there is no need for the gas flow to lift the material, as is the case with many calciners, gas and material velocities can be lower;
The heat exchange volume can be made sufficiently large, so the residence time of raw materials and gas can be reduced to 2 to 5 times compared to many conventional calciners.
Not only can the fuel be almost completely combusted in the calcination furnace, but also the heat exchange efficiency can be further increased, and the calcination rate of the kiln-large raw material can be increased to approximately 10%.

(2) The countercurrent preheater 4 used as a raw material preheater in the cement firing apparatus of this invention has a dispersion cone 5 at the top.
is provided, and the calciner waste heat is introduced from the lower part as a swirling flow to disperse the raw material, but furthermore, the upward swirling flow from the lower part of the middle or upper part of the countercurrent preheater main body 4a disappears or decreases. Since cooler bleed air or calciner waste heat is introduced tangentially into the preheater, excellent material dispersion not seen in conventional countercurrent preheaters is ensured.

Also, when feeding the raw material separated by the cyclone 2 into the upper part of the countercurrent preheater 4, air purge can be performed by introducing atmospheric air or cooler exhaust into the upper end of the raw material chute 2a (directly below the cone of the cyclone 2). The raw material becomes suspended with air and is supplied to the countercurrent preheater 4a, further improving the dispersibility of the raw material.

Therefore, countercurrent heat exchange between the gas and the raw material takes place under ideal conditions.

In addition, this preheater 4 is of a countercurrent type and has excellent dispersion of raw materials, so the gas velocity and raw material velocity can be lowered, and the heat exchange volume is large, so the residence time of raw materials and gas is considerably long. can do.

Therefore, in the calciner 9, even if the fuel is incompletely combusted, it is completely combusted in the lower part of the main body 4a of the preheater 4, and then the exhaust gas is transferred to the preheater main body while exchanging ideal countercurrent heat with the raw material. The temperature of the gas that rises inside 4a and is finally discharged from the cement firing apparatus is sufficiently lowered, and the heat consumption of the entire firing apparatus can be lower than that of a kiln with a preheater.

(3) The cement firing apparatus of the present invention is particularly suitable when solid fuel is used as the calcining fuel for the reasons shown in (1) and (2) above.

Even if a solid fuel such as coal, which has a slow combustion rate, is used in the calciner 9, the residence time in the furnace will be long and the combustion will be almost complete. Complete combustion occurs in the lower part of the main body 4a of the preheater 4.

Therefore, solid fuel can be used without causing inconveniences such as coaching troubles and increased heat consumption due to a decrease in the combustion rate of fuel in the calciner, as seen in conventional devices of this type.

Further, according to the firing apparatus of the present invention, the ro-kuri kiln 15
It is also possible to make all the fuel used in the calcining furnace 9 100% solid fuel, and furthermore, low-quality coal, bottons, a part of industrial waste, etc. can also be used as the calcining fuel.

(4) In the cement firing apparatus of the present invention, the main part of raw material preheating is performed using a countercurrent preheater 4 with low pressure loss, and a double cyclone type calcining furnace is used for raw material calcination. No. 9 has a lower gas velocity and lower pressure drop than conventional calciners, and furthermore, the calciner itself separates the raw materials and does not require a separation cyclone.

Therefore, the pressure loss of the entire device can be considerably reduced.For example, while the pressure loss of a conventional cement firing device of this type is about 70011L11LAq, it is about 50QmmAq in the same scale of the present invention.

The calcining furnace 9 of the cement firing apparatus of the present invention is provided with an upper chamber 9a and a lower chamber 9b, into which the kiln exhaust gas containing raw materials and the cooler bleed air are introduced, respectively.

Therefore, by adjusting the amount of raw material supplied to the compartment and the amount of kiln exhaust gas or cooler bleed air, it is possible to balance the pressures of the kiln exhaust gas system and the cooler bleed air system.

For example, if the pressure loss in the kiln exhaust gas system is increased in order to balance the pressures in both systems, more of the raw material from the preheater 4 will fall into the lower branch 18b than the upper branch 18a of the raw material introduction pipe 1P. It is better to supply more kiln exhaust heat gas to the lower chamber 9b of the calciner 9. Conversely, if you want to increase the pressure loss in the cooler bleed system, it is better to The more you supply, the better.
In either case, the pressure can be balanced while transferring heat due to the cyclone effect and the countercurrent contact effect between the raw material and the gas at the throttle section.

Therefore, like the conventional cement firing equipment of this type,
In order to balance the pressure, a restrictor or damper is installed in both systems, without causing any unnecessary structural pressure loss.
It is possible to balance pressure while effectively transferring heat.

(5) The cement firing apparatus of the present invention does not require the use of a preheater cyclone, a calciner, or a complicated and narrow structural part of a duct between them, as seen in conventional cement firing equipment of this type. No coaching problems will occur.

In other words, the countercurrent preheater 4 and calciner 9 have extremely low gas flow rates compared to conventional types, are structurally sufficiently large compared to conventional types, and are capable of isothermal fuel combustion and raw material combustion. Calcination is performed, there is no local heating, and coaching problems can be almost completely prevented.

Furthermore, coating formation at the kiln exhaust gas introduction section is prevented by the temperature drop caused by the supply of raw materials from the countercurrent preheater 4.
)can do.

It is therefore possible to use significantly higher amounts of chlorine- or alkali-containing feedstock than in conventional devices.

(6) In the cement firing apparatus of the present invention, the fuel is burned in the calciner at a low temperature, so no nitrogen oxides are generated.

Furthermore, by supplying a smaller amount of air than the air required for fuel combustion to the lower chamber 9b of the calciner 9 and causing incomplete combustion of the fuel, various reducing substances can be generated, and these substances can be , the upper chamber 9a and the lower chamber 9b of the calcining furnace 9? Nitrogen oxides in the supplied kiln exhaust gas can be immediately decomposed using the raw material as a catalyst and converted into harmless nitrogen gas.

Therefore, the amount of nitrogen oxides in the gas finally discharged from the cement firing equipment is extremely low, which brings good results in terms of pollution control.

(7) The cement firing apparatus of the present invention performs preheating, calcination, and raw material separation using a raw material preheater mainly consisting of an upright cylindrical countercurrent heater and a double cyclone type calciner, and is different from conventional equipment. The structure is simpler than that of the conventional refractory brick, which reduces construction costs and extends the life of the refractory brick lining.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a cement firing apparatus including a calcining furnace for cement raw materials according to the present invention, and FIG. 2 is a sectional view taken along line A-A in FIG. 1.
Figure 3 is a sectional view taken along line B-B in Figure 1, and Figure 4 is a cross-sectional view taken along line C-- in Figure 1.
C sectional view and FIG. 5 are DD sectional views of FIG. 1. 1 is an exhaust fan, 2 is a cyclone, 3 is an exhaust gas conduit, 4 is a countercurrent preheater, 4a is the main body of the countercurrent preheater, 4b is a raw material discharge chamber of the countercurrent preheater, 5 is a countercurrent preheater vessel dispersion cone,
6 is a raw material supply pipe, 7 is a calciner exhaust gas conduit, 8 is an air introduction hole for air purging, 9 is a calciner, 9a is an upper chamber of the calciner, 9b is a lower chamber of the calciner, and 9c is a calciner. Squeezed part of kiln, 10
a is a burner installed in the upper chamber of the calciner, 10b is a burner installed in the lower chamber of the calciner, 12 is a combustion air introduction pipe, 13 is a kiln exhaust gas supply pipe, 15 is a rotary kiln, and 16 is a burner of the rotary kiln. , 17 is a clinker cooler, 18 is a raw material discharge pipe, 19 is an exhaust gas discharge pipe, 20 is a raw material feed pipe, 2
1 and 22 are dampers for combustion air introduction pipes, 23 and 24 are dampers for kiln exhaust gas supply pipes, 25 are raw material introduction pipes, and 26
27 is a raw material dispersion air flow introduction pipe, 27 is a raw material dispersion air flow branch pipe, 2
8 is a damper provided on the raw material dispersion air flow introduction pipe; 29 is a damper for the raw material dispersion air flow branch pipe.

Claims (1)

[Claims] 1. A calcining furnace with an independent heat source is installed between the rotary kiln and a countercurrent preheater that preheats the raw materials, and the upper end of the main body of the countercurrent preheater is connected to a cyclone via an exhaust gas pipe, and the lower end is connected to a cyclone through an exhaust gas pipe. In a cement firing device that communicates with the calciner through a calciner exhaust gas pipe connected tangentially to the main body, the calciner is divided into an upper chamber and a lower chamber by a throttle, and the exhaust heat from the rotary kiln is divided into an upper chamber and a lower chamber. The gas discharge end and the upper and lower chambers of the calciner are connected in parallel and tangentially to the upper and lower chambers by the kiln exhaust gas supply pipe, and the clinker cooler and the upper and lower chambers of the calciner are connected in parallel and tangentially to the upper and lower chambers. The upper chamber and the lower chamber are connected in parallel and tangentially to the upper chamber and the lower chamber by a combustion air introduction pipe, and the upper or middle part of the main body of the countercurrent preheater is connected to the combustion air introduction pipe and the calciner exhaust gas pipe. are connected tangentially to the main body through a raw material dispersion airflow introduction pipe, and the raw material discharge chamber of the counterflow type preheater and the kiln exhaust gas supply pipe are communicated through a raw material discharge pipe, and the raw material is calcined in a calcining furnace. A calcining furnace for cement raw materials, characterized in that a raw material inlet pipe for supplying separated raw materials is provided between a raw material outlet at the lower end of a lower chamber of the calciner and a raw material inlet end of a rotary kiln. Including cement firing equipment.