JPH0126400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting control method that enables uniform cooling of powder or granular material in a dry cooling device for powder or granular material.

In the fields of steelmaking and chemical industry, high-temperature powder and granular materials are cooled by various methods. Among them, there is a dry cooling method that aims to recover waste heat from powder and granular materials. This is a method in which high-temperature powder and granules are put into a tower, cooling gas is circulated to recover the sensible heat of the powder and granules, and then converted into steam energy in a boiler. It is also used in red-hot coke extinguishing equipment. ing.

As an example, in the case of coke dry extinguishing equipment, as shown in Figure 1, 1 is the cooling tower body,
An input port 2 for charging high-temperature coke is provided at the top, and a discharge port 3 for discharging cooled coke is provided at the bottom. The upper part of this tower body 1 is connected to the upper part of a boiler 5 via a communication pipe 4.
The bottom of the cooling tower body 1 is connected to the lower part of the cooling tower body 1 by a connecting pipe 7 with a fan 6 interposed therebetween, so that cooling gas such as an inert gas can be circulated by driving the fan 6. A cutoff valve 8 is installed at the discharge port 3 to cut out coke in small batches.
By this operation, a downwardly moving bed of coke can be formed in the column body 1. Therefore, the moving bed of coke flows countercurrently to the cooling gas, and the coke is cooled and extinguished, while the cooling gas is heated to a high temperature. According to this, the coke can be extinguished and the boiler 5 can be heated by the sensible heat of the coke via the cooling gas, so that an energy saving effect can be achieved.
Note that 9 is an upper bunker to which an upper gate 10 is attached so as to be openable and closable, and 11 is a lower bunker to which a lower gate 12 is attached to be openable and closable.

Such dry cooling towers have a problem in that the coke is not cooled uniformly. If the nonuniformity became noticeable, high temperature coke would be mixed in the coke cut out from the discharge port 3 by the cutoff valve 8, which was dangerous. For this reason, conventionally, a plurality of temperature detection ends were placed on the circumferential wall of the cooling tower 1 to monitor uneven cooling of coke during operation, and when a large difference occurred in the temperature distribution on the circumferential wall, Based on the approximation and correlation with non-uniform cooling, the cutoff valve 8 was closed to stop coke discharge.
However, stopping the discharge of coke is undesirable because it limits the production capacity. In order to deal with the non-uniform cooling of coke without stopping the coke discharge, it is conceivable to assume in advance the non-uniform flow of cooling gas and coke and to determine the volume of the cooling tower body 1 that corresponds to the non-uniform flow. However, in this case, there will be a margin in the cooling capacity, and the tower body 1
The shape of the coke becomes large, which impairs economic efficiency as a facility for recovering the sensible heat of coke.
On the other hand, in order to deal with non-uniform cooling of coke, a method can be considered in which the supply amount of cooling gas is changed in response to the non-uniform cooling. That is, the cooling gas supply equipment is divided and provided, and the supply amount is increased to the under-cooled section and the supply amount is decreased to the over-cooled section, thereby uniformly cooling the coke. Furthermore, there is also a method of dividing the outlet of the cooling gas and appropriately limiting the amount of each gas discharged, thereby making coke cooling more uniform. There is also a method of increasing the amount of cooling gas supplied as a whole in order to supply the minimum amount of cooling gas required for cooling to the non-uniform cooling section. According to these methods of changing the supply amount of cooling gas, due to the unevenness of the particle size distribution of coke in the column body 1, the rising speed distribution of the cooling gas is compared to both wall surfaces 1a and 1b as shown in FIG. Even if the velocity is slow at the center 1c, by increasing the amount of gas supplied to the center 1c, the velocity distribution can be made uniform and the coke can be uniformly cooled. However, the tower body 1
Inside is a moving bed of coke, and if the coke descends at a high rate, there are limits to how the amount of cooling gas supplied can be changed. In other words, as shown in FIG. 3, the coke descending velocity distribution within the column body 1 is slowest at the center 1c, fastest between the center 1c and both wall surfaces 1a and 1b, and has a maximum value. If the conventional method is used to cool coke uniformly when the difference in the minimum value is large, it is necessary to send a large amount of cooling gas to ensure that sufficient cooling gas is distributed even to areas where the falling speed is high. However, in order to do so, the size of the fan 6 and the diameter of the gas passage must be increased, resulting in an increase in the scale of the equipment, which has the disadvantage of impairing economic efficiency.

An object of the present invention is to provide a method for controlling cutting in a dry cooling device for powder and granular material, which can uniformly cool powder and granular material without stopping the discharge of the powder and granular material, and which can improve the economical efficiency of the equipment. The goal is to provide the following.

In order to achieve the above object, the configuration of the present invention is as follows:
A radiation temperature sensor is installed to detect the temperature of the powder and granular material cut out from the cutting port at the bottom of the cooling tower. A granule cutting number detector is provided, and its signal is input to a computing unit to calculate the cutting speed from the amount of granular material cut out within a unit time.At the same time, the signal from the temperature sensor and the granular material The correlation with the cut-out speed is determined, and a regression analysis of the powder temperature against the powder cut-out speed is performed using a calculator, and the temperature of the powder cut out from each cut-out valve is set to a certain constant temperature. It is characterized by changing the cut-off speed of the cut-off valve, thereby uniformly cooling the powder and granular material in the cooling tower.

An embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 4, reference numeral 1 denotes a cooling tower body, and a discharge port 3 is provided at the bottom of the cooling tower body for discharging cooled granular material, that is, coke in this embodiment. A plurality of discharge ports 3 are provided, and each discharge port 3a,
Coke can be discharged from 3b. A cutoff valve 8a, 8b is installed at each outlet 3a, 3b, and each outlet 3a, 3b is opened or closed by the operation of each outlet valve 8a, 8b. Each cutting valve 8a, 8b is provided with cutting number sensors 13a, 13b for detecting the number of coke cuttings. Further, 15 is coke discharged from the lower gate 12, and 16 is a belt conveyor for conveying the coke. Reference numeral 17 denotes a radiation temperature sensor, which detects the coke 15 being placed on the conveyor 16 and moving.
Measure the temperature. This one temperature sensor 17 and the plurality of cutting number sensors 13a and 13b are electrically connected to a computing unit 18, and input a temperature signal and a cutting number signal to the computing unit 18. A coke cutting speed setting device 19 is connected to the computing unit 18 , and a coke cutting speed set value is input to the computing unit 18 .
The output side of the calculator 18 is connected to each cut-off valve 8a, 8b, and each cut-off valve 8 is activated by issuing an operation command signal 20.
Controls the operations of a and 8b.

To explain the function of the arithmetic unit 18, the first
Next, the first cutting speed is calculated from the cutting number signal.
That is, the first coke cutting speed v ₁ under normal conditions is calculated by the following equation.

v ₁ = Z x Q/t [tons/hour] ...(1) Here, t is the elapsed time [hours], Z is the number of times the coke is cut out within the elapsed time [times], and Q is the coke per time. Cutting amount [tons/number of times].

On the other hand, the first coke cutting speed during the transient period
v ₁ ′ is calculated using the following formula.

v ₁ ′=v ₀ ×t ₀ /t′ [tons/hour] …(2) Here, v ₀ is the coke cutting speed setting value [tons/hour]
], t ₀ and t', t ₀ = Q/v ₀ [hours/times]
, t'=t/c [hours/times], c is the integrated value of the number of times the coke is cut out [times]. The periods corresponding to transient periods include the start of coke cutting and the set value of coke cutting speed v ₀
This refers to the period from when the coke removal rate is changed until a predetermined period of time has elapsed, and is the period until the change in coke cutting rate stabilizes at the minimum necessary level.

Second, the calculator 18 receives the temperature signal and the first cutting speed.
From the correlation with v ₁ and v ₁ ′, a regression equation of coke cutting speed v ₁ and v ₁ ′ with respect to coke temperature θ is calculated. The regression equation for each cut-out valve is shown below. Note that x corresponds to the coke temperature detected by the temperature sensor 17, and y corresponds to the coke cutting speeds v ₁ and v ₁ '.

y=a _k x ^k +a _k-1 x ^k-1 +...a ₁ x+b...(3) (k is a positive integer) The above equation (3) is the k-order equation Z _ij = x ^j _i (i=1, …,n)(j=1,…,k) Calculate the sum of products for the values obtained by subtracting the average value from Z _ij and y _ij .

A= _o 〓 ^k=1 (Z _ki − _i ) (Z _kj − _j ) B= _o 〓 ^k=1 (Z _ki − _i ) (y _k −) S= _o 〓 ^k=1 (y _k −) ² The following calculation is performed for each m of orders m=1,...,k.

Regression coefficient a _n =A ^-1・B Constant term b=− _n 〓 ^k=1 Z Change due to _i regression R=B′・a Change from _n regression E=S−R F ratio (n−m−1) R/m・E Here, x _i is the i-th temperature detection value of the coke discharged n times from the discharge port 3a or 3b, and y _i is the i-th temperature detection value of the coke discharged n times from the discharge port 3a or 3b. This is the first cutting speed.

Thirdly, the calculator 18 calculates the average value M of the coke temperature θ. It is calculated according to the following formula.

M=1/nΣθ _i …(4) Here, θ _i is the discharge port 3 by the temperature sensor 17
This is the temperature detection value of the i-th coke discharged from a and 3b.

Fourthly, the calculator 18 calculates the second cutting speeds v ₂ and v ₂ ' with respect to the average coke temperature M using a regression equation,
The coke cutting time intervals T and T' in each cutting valve 8a and 8b are calculated from the ratio of the speed and the first cutting speed, that is, v ₁ /v ₂ and v ₁ '/v ₂ '. That is, the normal coke cutting time interval T is calculated by the following equation.

T=t ₀ ×(v ₁ /v ₀ )×(v ₁ /v ₂ ) [hours] (5) On the other hand, the interval T′ of the coke cutting time during the transient period is calculated by the following equation.

T'= _t0 ×( _v1 '/ _v0 )×( _v1 '/ _v2 ') [time]...(6) Next, the operation of the apparatus shown in FIG. 4 will be described.

A cutting speed setting value v ₀ is set in the cutting speed setting device 19, and the intervals T and T' of the coke cutting time of each cutting valve 8a and 8b are adjusted via the computing unit 18. At this time, the cutting speeds v ₁ and v ₁ ' of the cutting valves 8a and 8b change, and the descending speed of coke within the cooling tower body 1 changes.

When non-uniform cooling of coke occurs during normal times, the temperature signal from the radiation temperature sensor 17 and the corresponding cutoff valve 8 at the discharge ports 3a, 3b are detected.
From the correlation with the first cutting speed v ₁ of a and 8b, the computing unit 18 calculates a regression equation of the coke cutting speed v ₁ against the coke temperature θ, and from each temperature signal, the computing unit 18 calculates the average coke temperature. Calculate M. The coke cutting speed (second cutting speed) v ₂ of each cutting valve 8a, 8b that achieves this average coke temperature M is calculated by a regression formula, and further, for each cutting valve 8a, 8b, The ratio (v ₁ /v ₂ ) of the first cutting speed v ₁ to the second cutting speed v ₂ is calculated, and from that ratio (v ₁ /v ₂ ), each cutting valve is Calculate the interval T of coke cutting time in 8a and 8b. Therefore, if the coke temperature θ is higher than the average coke temperature M, the temperature sensor 1
Cutoff valves 8a and 8b corresponding to the locations detected in step 7
is controlled by the calculator 18 so that the interval T of the coke cutting time becomes longer, the cutting speed v ₁ decreases, and the coke descending speed is slowed down. the result,
The cooling effect of the countercurrent cooling gas increases, and coke cooling becomes uniform. Conversely, the cutoff valves 8a and 8b corresponding to the locations where the temperature sensor 17 detects that the coke temperature θ is lower than the average coke temperature M are controlled by the calculator 18 so that the interval T thereof is shortened. The cutting speed v ₁ increases, increasing the coke descent speed. As a result, the cooling effect of the countercurrent cooling gas decreases, and coke cooling becomes more uniform.

In the case of non-uniform cooling of coke during a transient period, the calculation unit 18 calculates a regression equation from the coke temperature θ and the first cutting speed v ₁ , as in the case described above, and calculates the average value of the coke temperature θ. M is also calculated. Each cutoff valve 8 such that the average coke temperature M is achieved.
Coke cutting speed of a and 8b (second cutting speed)
v ₂ ′ is calculated by a regression equation, and _the first
The ratio of the cutting speed v ₁ ′ (v ₁ ′/v ₂ ′) is calculated, and from that ratio (v ₁ ′/v ₂ ′), each cutting valve 8
Calculate the interval T' of the coke cutting time at a and 8b. By operating each cutoff valve 8a, 8b at the interval T' calculated in this way, it is possible to prevent uneven coke cooling even in a transient state.

By appropriately repeating the above operations, coke can be cooled uniformly both in normal times and in transient times.

Note that the radiation temperature sensor 17 is not installed inside the cooling tower body 1 like a thermocouple, but is installed outside the tower body 1.
The coke is cut out from each cutoff valve 8a, 8b and falls from the lower gate 12 onto the belt conveyor 16, where the temperature of the coke is immediately detected as it is conveyed in a rod shape on the conveyor 16.

In other words, when a thermocouple is installed inside the cooling tower body 1, the thermocouple must be buried inside the tower wall bricks to prevent wear, which makes it impossible to accurately measure the temperature of coke inside the tower body 1. The coke inside the column body 1 is still in the process of being cooled, and cannot be called cooled coke. Furthermore, the thermocouple detects the temperature of the gas within the tower body 1 due to the influence of the gas, and the response is also slow. However, if the radiation temperature sensor 17 is installed outside the tower body 1 as shown in FIG. 4, it is possible to measure the true temperature of the coke after cooling without any disturbance. The installation environment is better than in the case where the valves 8a and 8b are installed, the service life can be expected to be longer, and the maintenance is easier.Moreover, the response is fast, so changes in process values can be quickly detected and the cutoff valves 8a and 8b
Easy to use for control.

Furthermore, since the temperature is not cut out from a plurality of cut-off valves at the same time and the response is fast, even if there are a large number of cut-out valves, the temperature can be measured with one radiation temperature sensor.

As described above, according to the present invention, it is possible to uniformly cool the powder or granular material without stopping the discharge of the powder or granular material, improve the operating rate of the dry cooling device, and By using valves to control the opening and closing operations of each cut-off valve, it is possible to control the descending speed of the powder and granular material within the cooling tower body, and it is possible to reliably uniformize the cooling of the powder and granular material. In addition, with a calculator,
By performing a regression analysis of the powder cutting speed against the powder temperature and controlling the operation of each cutting valve based on this cutting speed, uneven cooling of the powder and granular material can be improved. , it is possible to promote downsizing of equipment and improvement of economic efficiency, and moreover, it is possible to control the cutoff valve during normal and transient times. In particular, since the temperature of the powder cut out from the cutting opening at the bottom of the cooling tower is detected by a radiation temperature sensor, there is no disturbance compared to when thermocouples are installed inside the cooling tower, and the temperature of the coke after cooling is reduced. It detects the true temperature of the material, has a fast response, and achieves uniform cooling of powder and granular materials with high precision.Moreover, it has a good installation environment, can be expected to have a long life, and is easy to maintain.

[Brief explanation of drawings]

Figure 1 is a vertical elevational view showing an example of a conventional coke dry extinguishing system, Figure 2 is an explanatory diagram showing the distribution of the cooling gas rising speed ratio in the cooling tower body of Figure 1, and Figure 3 is the FIG. 4 is an explanatory diagram showing the descending velocity ratio distribution of powder and granular material in the cooling tower body, and FIG. 1...Cooling tower body, 3a, 3b...Discharge port, 8
a, 8b... Cutting valve, 13a, 13b... Cutting number sensor, 15... Powder, 17... Radiation temperature sensor, 18... Computing unit, 19... Cutting speed setting device, 20...Operation command signal.

Claims (1)

[Claims] 1. A radiation temperature sensor is provided to detect the temperature of the powder and granular material cut out from the cutting port at the bottom of the cooling tower, and a plurality of cut-out valves provided in the powder and granular material cutting device at the bottom of the cooling tower are equipped with A powder cutting number detector is provided, and its signal is input to a calculator to calculate the cutting speed from the amount of powder cut out within a unit time.At the same time, the signal from the temperature sensor and the powder The correlation with the powder cutting speed is determined, and a regression analysis of the powder temperature against the powder cutting speed is performed using a calculator, so that the powder and granular material cut out from each cutting valve has a certain temperature. A cutting control method in a dry cooling device for powder and granular material, characterized in that the cutting speed of each cutting valve is changed, thereby uniformly cooling the powder and granular material in a cooling tower.