JPS61141924A - Stock powder preheating apparatus with waste heat utilizing equipment - Google Patents

Abstract

PURPOSE:To efficiently recover the sensible heat of exhaust gas, by arranging a shortcircuit gas conduit opened not only to the duct of a lower stage or the inlet end of a combustion furnace at one end thereof but also to the exhaust gas duct reaching the waste heat utilizing equipment of an exhaust system at the other end thereof. CONSTITUTION:Because the hot gas extracted from a gas duct 7a is not used in the heat exchange with the stock powder in the downstream side of the gas extraction part and retains high temp., said hot gas is allowed to meet with the exhaust gas in a gas duct 15 to raise the temp. of the exhaust gas finally introduced into a boiler 16. Therefore, the heat recovered in the boiler 16 increases to a large extent and, at the same time, the temp. and pressure of generated steam become high and, therefore, the power generation efficiency in a turbine is markedly improved. When a flow controller 20 is provided to the proper place of a shortcircuit gas duct 19 and a shortcircuit hot gas amount is controlled, the temp. of the exhaust gas introduced into waste heat utilizing equipment can be enhanced to arbitrary temp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a raw material powder child heating device installed in an apparatus for firing powdered raw materials such as cement raw materials and aluminum hydroxide, such as a cyclone type multistage preheating device. This relates to a device that can efficiently recover and utilize exhaust gas sensible heat. Figure 1 shows an example of a device used to preheat and fire cement raw materials. This device is mainly used to collect raw material powder. From a preheating device 1, a firing furnace 3, and a clinker cooler 4, which are vertically arranged cyclones C1 to C3 as containers, a separation cyclone C4, and a calcining furnace 2 with a combustion device constituting the lowest heat exchange stage. In these operations, the raw material powder A is sent from the feeder 5 into the duct 7a, heated by the hot gas rising inside the duct 7a, separated from the hot residue by the cyclone C1, and sent to the raw material chute. It enters the next gas duct 7b through 8a and is heated sequentially through the same process.Finally, it is calcined in a calcining furnace 2 equipped with a burner 6a, enters a separation cyclone C4, and then passes through a raw material chute 8d. It is introduced into the firing furnace 3 through the firing furnace artificial wheel 12.

High-temperature air from the cooler 4 and firing fuel from the burner 6b are introduced into the firing furnace 3, and the clinker that has been fired at high temperature enters the clinker cooler 4 and is cooled, and is further transferred to the tallinker conveyor. 11. Reference numeral 9 indicates a surplus air ventilation fan, 10 a forced air blower, 13 an air bleed duct, 14 an exhaust gas induction fan, and 15 an exhaust gas duct.

The temperature of the exhaust gas discharged from the uppermost cyclone C1 of the preheating device 1 in such a baking device is usually around 350 to 400°C, although it depends on the heat exchange method and the number of stages in the preheating device 1, and it still consumes a considerable amount of thermal energy. or left behind. Therefore, in order to utilize this exhaust gas sensible heat more effectively, exhaust heat utilization equipment such as a boiler 16 is installed in the middle of the exhaust gas duct 15 as shown in Fig. 1, and steam is generated by heat exchange with the high temperature exhaust gas. By using this for power generation, etc., we aim to improve thermal economy. In addition, in order to cope with the case where the wood pipe of the boiler 16 is damaged, a bypass tact 17 is provided to bypass the boiler 16, and a tamper 18 is installed on the wood pipe 15 of the duct.
a. A damper 18b is provided in the bypass duct I/17, and the operation of the firing apparatus can be continued by opening and closing these dampers.

However, in such conventional exhaust heat utilization equipment, the temperature of the exhaust gas in the exhaust gas duct 15 is not that high, so the boiler 1
6, the temperature and pressure of the generated steam do not decrease sufficiently, resulting in low power generation efficiency in the turbine. Moreover, since the exhaust gas from the preheating device 1 is generally used as a heat source for drying raw materials, only the surplus can be used for heating in the boiler 16, and as a result, there is a shortage of available gas sensible heat, which is used for power generation. Turbine efficiency is not high enough.

As a way to compensate for this lack of heat, exhaust gas duct 15
It is conceivable to install a combustion chamber in an appropriate location and supply fuel and combustion air to raise the exhaust gas temperature, but providing a combustion section other than a calciner or calcination furnace is difficult both in terms of equipment and operation. That's not a good thing. Moreover, when cheap coal is used as fuel, it becomes difficult to dispose of combustion residual ash generated in the combustion chamber.

The present inventor focused on the above-mentioned fundamental circumstances and conducted research in order to increase the sensible heat of exhaust gas and improve the heat utilization efficiency of exhaust heat utilization equipment such as boilers for power generation turbines. The present invention was completed as a result of such research, and its configuration consists of vertically arranging multiple stages of raw material powder collectors above the inlet end layer of the firing furnace, as shown in FIG. A raw material powder container comprising an exhaust heat utilization equipment attached to an exhaust gas system of a preheating device which connects the raw material powder collectors and between the lowest raw material powder collector and the inlet end cover by gas ducts, respectively. In thermal equipment,
In order to increase the temperature of the exhaust gas introduced into the exhaust heat utilization equipment and increase its heat utilization efficiency, one end is opened to the lower stage gas duct or the inlet cover of the firing furnace, and the other end is opened to the exhaust gas system exhaust heat utilization. The gist is that a short-circuit gas conduit is provided that opens into the exhaust gas duct leading to the equipment, and a dust collector is provided in the middle of the short-circuit gas conduit.

The configuration and effects of the present invention will be explained below based on drawings showing embodiments. In addition to the above, it is within the technical scope of the present invention to appropriately modify and implement the specific configuration of the exhaust heat utilization equipment.

FIG. 2 is a schematic explanatory diagram showing an embodiment of the present invention, and the overall configuration can be understood based on the example in FIG. 1. The characteristic parts of this example are the exhaust gas duct 15 from the preheating device 1 to the exhaust heat utilization equipment such as the boiler 16, and the preheating device 1.
The hot gas extracted from the gas duct 7a by short-circuiting the uppermost cyclone C1 is combined with the exhaust gas discharged from the cyclone C1 and guided to the boiler 16. It's in a similar location. That is, the hot gas extracted from the gas duct 7a is not used for heat exchange with the raw material powder on the downstream side (downstream side as seen in the gas flow direction, the same applies hereinafter) of the oil gas section, and maintains a high temperature. Therefore, if this is combined with the exhaust gas in the exhaust gas duct 15, it will eventually flow into the boiler 1.
The temperature of the exhaust gas introduced into 6 increases. Therefore, the heat recovered by the boiler 16 increases by a large amount, and at the same time, the temperature and pressure of the generated steam increase, so that the power generation efficiency of the turbine is significantly improved. The hot gas bleed positions are not limited to the illustrated example, but include gaskets 1 to 7b and 7c.

7d, or directly from the inlet end cover 12 of the calcination furnace 2 or firing furnace 3, or from a plurality of locations if necessary.

At this time, since the temperature of the hot gas flowing from upstream is high, the amount of oil needed to raise the exhaust gas temperature to a constant level is small. On the other hand, the exhaust gas temperature changes depending on the amount of oil in the hot waste, and as this increases, the exhaust gas temperature rises. Therefore, as shown in FIG. By adjusting the amount of short-circuit hot gas using the flow rate regulator 20 according to the temperature required to efficiently operate the utilization equipment, the temperature of the exhaust gas introduced into the exhaust heat utilization equipment can be increased to an arbitrary temperature.

Furthermore, as shown, a short-circuit gas conduit 1 to an exhaust gas duct 15 is provided.
A temperature detector 21 is disposed downstream of the junction of No. 9, an opening regulator 22 is connected to the flow regulator 20, and the detector 21 and regulator 22 are connected to a control device 23.
By controlling the amount of short-circuit gas so that the exhaust gas temperature detected by the detector 21 is at a predetermined value, the temperature of the exhaust gas introduced into the exhaust heat utilization equipment can be kept as constant as possible even if the operating status of the firing equipment changes. can be maintained. As a result, the amount of heat supplied to the exhaust heat utilization equipment becomes constant, its operating state becomes stable, and in the case of a power generator, a constant amount of power can be obtained at all times. Further, the setting of the amount of power generation can be adjusted as necessary, and furthermore, an increase in the amount of fuel used in the firing apparatus due to short-circuiting a part of the high-temperature gas can be minimized.

At this time, in order to prevent the raw material powder from being discharged from the preheating device to the exhaust gas system along with the short-circuit gas, it is necessary to install a dust collector 24 in the middle of the short-circuit gas conduit 19 as shown in the figure. The fine powder discharged together with the dust collector 24 may be captured by the dust collector 24 and returned through the chute 25 to, for example, the lower heat exchange stage or the entrance mold 12 of the calcination furnace 2 or firing furnace 3.

FIG. 3 shows another embodiment of the present invention, in which the preheating device 1 does not include a calcining furnace, and the lowermost cyclone C4 is directly connected to the artificial end type 12 of the calcining furnace through a gas duct 7d.
The configuration is the same as the example shown in Fig. 2, except that the oil position of the hot gas and the return position of the fine powder captured by the precipitator 24 have been changed, but since there are many short-circuited heat exchange stages, the short-circuited gas conduit 19
The cross-sectional area and dust collector can be small, and multiple stages of dust collectors can be installed if necessary.

As described above, in the present invention, a part of the high-temperature gas in the preheating device 1 is short-circuited to the exhaust gas duct without performing heat exchange with the raw material powder, and the efficiency of preheating the raw material powder in the preheating device 1 is slightly increased. It increases the exhaust gas temperature at the expense of
Accordingly, it becomes necessary to increase the amount of fuel used in the calcining furnace 2 or the firing furnace 3. However, this increased amount of heat can be fully recovered through the effective use of the exhaust heat utilization equipment by increasing the exhaust gas temperature, and the overall energy economy is considerably improved over the conventional example. Moreover, since the amount of fuel originally used in the calciner 2 and the calciner 3 is only increased, there is no risk of an increase in equipment and operational burden compared to the case where fuel is supplied to the exhaust gas system. In addition, even when solid fuel such as pulverized coal is used as fuel, the ash produced by combustion is consumed as part of the cement raw material in the calcination device, so no special ash processing equipment is required.

In addition, in the present invention, it has been explained that it can be used as an apparatus without the calcining furnace 2 as shown in FIG. It is preferable to connect a calcining furnace 2 equipped with a combustion device to the lower castaf and absorb temperature changes caused by hot gas and oil in the preheating device 1 by adjusting operating conditions of the calcining furnace 2. Furthermore, in order to increase the heat utilization efficiency of the exhaust heat utilization equipment, the present invention increases the exhaust gas temperature at the expense of preheating efficiency as described above. Therefore, when the exhaust heat utilization equipment is not operated, the second , 3, the flow rate regulator 20 in FIG. 3 is fully closed, the hot gas is not short-circuited, and the preheating device 1 is used so as to exhibit the highest thermal efficiency.

The plan view shows an example in which one series of preheating devices is combined for one firing furnace 3, but two sets of preheating devices are combined for one firing furnace 3.
At least one of the preheating devices installed in the series or above
It is also possible to apply the technology of the present invention to the series and to combine the exhaust gas from multiple series and guide it to the exhaust heat utilization equipment. In addition to the boiler for power generation Tahin as shown in the figure, exhaust heat utilization equipment includes various types of firing equipment, such as raw material drying equipment such as rotary dryers, and raw material drying and simultaneous crushing equipment using roller mills, ball mills, etc. Examples include band equipment and various nearby heat demand facilities.

The present invention is generally configured as described above, but the key point is that a part of the heat waste on the second flow side is short-circuited to the exhaust gas tough 1- by skipping at least one heat exchange stage. It was possible to raise the exhaust gas temperature, thereby increasing the amount of heat supplied to the exhaust heat utilization equipment and significantly increasing its heat utilization efficiency. This increase in recovered energy {circle over (2)} more than compensated for the increase in fuel used in the firing furnace, etc., and the energy economy of the entire preheating, firing, and waste heat utilization equipment was significantly improved.

At this time, since a dust collector is disposed in the middle of the short-circuited waste conduit, it is necessary to prevent the raw material powder from escaping from the preheating device to the exhaust gas tough as much as possible.

The device of the present invention has an extremely simple configuration and can be easily applied to existing equipment equipped with exhaust heat utilization equipment. Furthermore, the pressure drop in the preheating device is reduced due to the reduction in the amount of gas passing through the short-circuit heat exchange stage of the preheating device, or the circulation and accumulation of harmful components such as alkaline content in the combustion gas due to the short-circuiting gas is reduced. There are also side effects.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a known raw material powder child heat/calcination and waste heat utilization equipment, Fig. 2 is an explanatory diagram showing an embodiment of the present invention, and Fig. 3 is an explanatory diagram showing another embodiment of the present invention. FIG. 1... Preheating device 2... Calcining furnace 01-C4・
... Raw material powder collector 3 ... Calcining furnace 4 ... Tarin car cooler 7
...Gas duct 15...Exhaust gas duct 16.
...Exhaust heat utilization equipment 19...Short-circuit gas conduit 20...
・Flow rate regulator

Claims (4)

[Claims] (1) A plurality of stages of raw material powder collectors are arranged vertically above the inlet end cover of the firing furnace, and between the raw material powder collectors and between the raw material powder collector at the lowest stage and the inlet end cover. In a raw material powder child heating device in which exhaust heat utilization equipment is attached to the exhaust gas system of a preheating device, each of which is connected by a gas duct, in order to increase the temperature of the exhaust gas introduced from the preheating device to the exhaust heat utilization equipment, A short-circuiting gas conduit that short-circuits a portion of the hot gas is installed from the lower stage gas duct or the inlet cover of the kiln to the exhaust gas duct up to the waste heat utilization equipment of the exhaust gas system, and the short-circuited gas conduit is A raw material powder child heating device with exhaust heat utilization equipment characterized by having a dust collector installed in the middle. (2) A raw material preheating device according to claim 1, in which a powder discharge port of a dust collector disposed in the middle of a short-circuit gas conduit is connected to a suitable location of a preheating device or to an inlet end cover of a firing furnace. (3) In claim 1 or 2, the raw material powder is obtained by connecting a calcination furnace equipped with a combustion device to a gas duct that connects the lowest stage raw material powder collector and the inlet end cover of the calcination furnace. Child heat device. (4) In any one of claims 1 to 3,
A temperature detector is installed in the exhaust gas duct leading to the exhaust heat utilization equipment, and a flow rate regulator for the passing gas and an opening regulator for the regulator are installed in the short-circuit gas pipe, and the temperature detected by the temperature detector is A raw material powder apparatus comprising: a control device that operates the opening degree adjuster according to a signal from the detector so that the temperature of the raw material powder becomes a predetermined value.