JPS5893781A - Controlling discharge of lump coke in dry cooling tower - Google Patents

Abstract

PURPOSE:To adjust discharge speed of lump coke and accomplish uniform cooling, by calculating time for taking out lump coke through a discharge valve by means of a computer which receives discharge frequency and temperature signal inputs and thereby controlling the action of discharge valve. CONSTITUTION:A predetermined value of discharge speed is set in a speed fixing device 24 and intervals of lump coke discharge through discharge valves 8a, 8b for discharge orifices 3a, 3b at the bottom of a cooling tower 1 are calculated by means of a computer 23. When lack of uniformity in cooling takes place, the computer calculates the temperature difference based on temp. signals sent from 1st thermosensor 15, 16 at the discharge orifice 3a, 3b and 2nd thermosensor 22 at the top pf a cooling gas blower 21 located at the center of the bottom of tower. The computer then calculates 1st discharge speed at the discharge orifice 8a, 8b based on discharge frequency signals from frequency sensor 13, 14, 2nd discharge speed at the discharge orifices 8a, 8b and lump coke discharge internals from the ratio of the 1st to the 2nd discharge speeds.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting control method that enables uniform cooling of grain agglomerates in a dry cooling tower for grain agglomerates.

In the fields of steelmaking and chemical industry, cooling of high-temperature agglomerates is carried out by various methods. Among them, there is a dry cooling method for the purpose of recovering waste heat from granules. This involves putting high-temperature agglomerates into the tower body, circulating cooling gas to recover the sensible heat of the agglomerates, and
This is a method of converting energy into steam in a boiler, and is used in red-hot coke extinguishing equipment.

To give an example of a conventional coke dry cooling tower, as shown in Fig. 1, 1 is a tower body with an inlet 2 at the top for injecting high-temperature coke, and an exhaust at the bottom for discharging cooled coke. An exit 3 is provided. 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 tower body 1 and the lower part of the tower body 1 are connected to a connecting pipe 7 with a fan 6 interposed therebetween.
The cooling gas (inert gas, etc.) can be circulated by driving the fan 6. Vent,
3 is a cut-off valve 8 that cuts out coke in small batches.
is installed so that a downward moving layer of coke can be formed in the column body 1 by operating the cutoff valve 8. 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 the energy saving effect can be improved. In addition, 9 is an upper bunker, and an upper gate 10
is attached so that it can be opened and closed, and 11 is a lower bunker, and a lower gate 12 is attached so that it can be opened and closed.

Such dry cooling towers have a problem in that the coke is not cooled uniformly. If the nonuniformity became significant, 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, in the past, multiple temperature detection ends were placed on the circumferential wall of the column body 1 to operationally monitor the non-uniform cooling of coke, and when a large difference occurred in the temperature distribution of the circumferential wall soil. To,
Judging from the approximation and correlation to non-uniform cooling, the cutoff valve 8 was closed to stop coke discharge. However, stopping the discharge of coke is undesirable because it limits production capacity. In order to deal with the non-uniform cooling of coke without stopping the discharge of coke, it is conceivable to assume in advance the non-uniform flow of cooling gas and coke and to design the shape of the column body 1 to match this. However, in this case, there is a margin in the cooling capacity, and the shape of the tower body 1 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, at the outlet of the cooling gas, the outlet is divided and the amount of each gas discharged is appropriately restricted.
There are also methods to make 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 changed to the two wall surfaces 1a as shown in FIG.

Even if the velocity is slower at the center 1C than at the center 1b, by increasing the amount of gas supplied to the center 1C, the velocity distribution can be made uniform and the coke can be cooled uniformly.

However, inside the tower body 1, there is a moving layer of coke.
When the rate of descent of coke is high, there are limits to how the amount of cooling gas supplied can be changed. In other words, as shown in FIG.
When the speed is slowest at the center and fastest between the center 1C and both wall surfaces ia and 1b, and the difference between the maximum and minimum values is large, if you use the conventional method to cool the coke uniformly, , it is necessary to send a large amount of cooling gas to ensure that sufficient cooling gas is distributed even to areas where the descent speed is high.
For this purpose, the size of the fan 6 must be increased and the airtightness of the tower body 1 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 the cutting of agglomerates in a dry cooling tower, which can uniformly cool the agglomerates without stopping the discharge of the agglomerates, and can improve the economic efficiency of the equipment. be.

In order to achieve the above object, the present invention provides a plurality of exhaust ports at the bottom of the column, based on the knowledge that non-uniform cooling of grain agglomerates is mainly caused by non-uniform falling speed of grain agglomerates, and A cut-off valve is installed at the outlet, and a cut-off frequency sensor is installed on each cut-off valve to detect the number of times the granules are discharged.Multiple temperature sensors are attached to the wall of the tower body corresponding to each outlet. A temperature sensor is also attached to the top of the cooling gas blowing part located in the center of the bottom.
The agglomerate cutting time interval of each cut-out valve is calculated by a calculator that inputs the number of cuttings and the temperature signal, and by controlling the operation of each cut-out valve, the descending speed of the agglomerates is adjusted and the particles are removed. We have discovered a cutting control method that uniformizes the cooling of the lump.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 4, 1 is a column body, and an outlet 3 is provided at the bottom of the column body for discharging the cooled granules (hereinafter referred to as coke). As shown in FIG. 5 or 6, a plurality of discharge ports 3 are provided, and each discharge port 3a, 3b, 3
Coke can be discharged from c and 3d.

As shown in FIG. 4 again, each discharge port 3 is provided with a cutoff valve 8, and the discharge ports 3a and 3b are opened and closed by the operation of the cutoff valves 9a and 8b. Each cut-off valve 8
A, 8b are provided with cutting number sensors 13, 14 6- for detecting the number of times the grain agglomerates are cut out.

First temperature sensors 15 and 16 are attached to the inner wall of the column body 1 in correspondence with the respective discharge ports 3a and 3b, and as shown in FIG. 5 or 6 again, the respective discharge ports 3a.

A plurality of first temperature sensors 15, 16, 17, 18, 19, and 20 are arranged at positions facing 3b, 3c, and 3d. A second temperature sensor 22 is attached to the top of the cooling gas blowing section 21 located at the center of the inner bottom of the tower body 1 . The first temperature sensor 15.16, the second temperature sensor 22, and the cutting number sensors 13, 14 are electrically connected to the calculator 23 as shown in FIG. The number signal is input to the calculator 23. Arithmetic unit 23
A coke cutting speed setting device 24 is connected to the coke cutting speed setting device 24, and a coke cutting speed setting value is inputted to the arithmetic unit 23. The output side of the calculator 23 is each cut-off valve 8a.

8b, and controls the operation of each cutoff valve 3a, 9b by issuing an operation command signal 25. 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.

To explain the functions of the calculator 23, first, the first cutting speed is calculated from the cutting number signal. That is, the first coke cutting speed v1 in normal conditions is calculated by the following equation.

Here, t is the elapsed time, and 2 is the number of seconds within the elapsed time.
The number of times the coke is cut out [times], and Q is the amount of coke cut out per time [tons/time].

On the other hand, the first coke cutting speed V'l during the transient period is calculated by the following equation.

Here, vo is the coke cutting speed setting value [tons/hour-]
, to and t', to=Q/v.

[hour 7 times], t'=t/c [hour 7 times], C is the integrated value of the number of coke cuttings [times]. The period corresponding to the transition period is the start of coke cutting and the set value of coke cutting speed v.
6 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 computing unit 23 calculates the temperature difference Δθ of the coke near the wall with respect to the center of the column body 1 from the first temperature signal and the second temperature signal.
Calculate. The relational expression for the temperature difference Δθ is as follows.

Δθ=1θ−θol['c) (3) Here, θ is the temperature detection value at each of the first temperature sensors 15 and 16, and θ0 is the temperature detection value at the second temperature sensor 22.

Thirdly, the calculator 23 calculates the temperature difference Δθ and the first cutting speed vt,
A regression line of the coke cutting speeds Ml and V'l with respect to the temperature difference Δθ is calculated from the correlation with v't. The equation of the regression line is shown below. Note that X is the temperature difference ΔQ1y and the coke cutting speed v1. Corresponds to v'1.

y=ax-1-b...(4) Here, the number of Ny first temperature sensors 15, 16, xl is i
th first temperature sensor 15, 16 and second temperature sensor 22
The temperature difference, yl, is the cutoff valve 8 a p 8 b of the outlet 3 a , 3 b corresponding to the first temperature sensor 15 , 16 .
is the first cutting speed at .

Fourth, the calculator 23 calculates the average value M of the temperature differences Δθ. It is calculated according to the following formula.

M=, Σ1θi−θ. 1 [℃] ・Song・(5) Here,
θ1 is the temperature detection value at the i-th first temperature sensor 15, 16.

Fifth, the computing unit 23 calculates the average value M of the temperature difference using the regression line.
The second cutting speeds Vt and V'fi for the second cutting speeds v2. v'2 and the first cutting speed vl, v'l
The coke cutting time intervals T and T' in each cutting valve 8a and 8b are calculated from the ratio. That is, the normal coke cutting time interval T is calculated by the following equation.

On the other hand, the interval T' of the coke cutting time during the transient period is calculated by the following equation.

In addition, as shown in FIG. 5, the first temperature sensor 15.19
, 16, 17, 20, 18 are the discharge ports 3a, 3b, 3
If the number is different from the number of c and 3ct, please prepare the discharge port 3
A plurality of first temperature sensors 15, 19.16°1? correspond to each of b + 3 c t 3 d. .
4-2) Used in formula.

Next, the operation of the present invention will be described.

In FIG. 4, the cutting speed set value Vll is set in the cutting speed setting device 24, and each cutting valve 8 a is set via the calculator 23.
#8 Interval T of coke cutting time of b,
Adjust T'. At this time, each cut-off valve 8a.

Cutting speed v at 8b 1. v/! changes, and the descending speed of coke within the column body 1 changes.

When non-uniform cooling of coke occurs during normal times, the temperature signal from each of the first temperature sensors 15 and 16 and the temperature signal from the second temperature sensor 22 are subtracted by the calculator 23 to calculate the temperature difference Δθ. In addition, each first temperature sensor 15,1
The discharge ports 3a corresponding to 6, 3. b cut-off valve 8a, -8
The first cutting speed vl at b is measured by each cutting number sensor 13,
It is calculated by the calculator 23 from the cutting number signal from 14. From the correlation between the temperature difference Δθ and the first cutting speed vl, the computing unit 23 calculates a regression line of the coke cutting speed with respect to the temperature difference. The average value M of the temperature difference Δθ is calculated by the calculator 23, and each cut-off valve 8a, 8b is calculated so that the average value M of the temperature difference Δθ is calculated.
The cutting speed (second cutting speed) v! is calculated by a regression line, and further, the ratio of the first cutting speed vl to the second cutting speed v2 for each cutting valve ga and 8b (v, /v, '
), and from the ratio (v, /v, ) above (6)
Specifically, the interval T of coke cutting time at each cutting valve 8a, 9b is calculated as shown in the formula. Therefore, the cut-off valves F3a and 8b corresponding to the locations where the first temperature sensors 15 and 16 detect that the coke temperature is high are controlled by the calculator 23 so that the interval T thereof becomes longer, and the cut-off speed v1 decreases, slowing down the coke fall rate. As a result, the cooling effect due to the countercurrent cooling gas is improved, and the coke can be cooled uniformly. Conversely, the cutting valves 8a and 8b corresponding to the locations where the first temperature sensors 15 and 16 detect that the coke temperature is low are controlled by the calculator 23 so that the interval T thereof is shortened, and the cutting speed is V
l increases, increasing the coke fall rate. the 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 temperature difference Δθ error first cutting speed v'1 is calculated by the calculator 2 as described above.
3 to calculate the regression line. Further, the average value M of the temperature difference Δθ is calculated by the calculator 23, and the cutting speed (second cutting speed) v' of each cutting valve ga, 8b is adjusted so that the average value M of the temperature difference Δθ becomes this value M.
2 is calculated by the regression line, and further, each cut-off valve 8a,
Second cutting speed v' every 8b! The first cutting speed V'
Calculate the weight ratio (V'l/V'yi) and calculate the ratio (v/
, /vz, ), the interval T' of the coke cutting time at each cutting valve 8a, 8b is calculated as shown in the above equation (1). The interval T calculated in this way
By operating the respective cut-off valves 8a and 8b at ', it is possible to prevent uneven cooling of coke even during a transient period.

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

As is clear from the above description, the present invention provides the following effects.

(1) Since the grain agglomerates can be uniformly cooled without stopping the discharge of the grain agglomerates, the operating rate of the dry cooling tower is improved.

(2) By using multiple cut-off valves and controlling the opening and closing operations of each cut-off valve, it is possible to control the descending speed of the agglomerates within the tower body, ensuring uniform cooling of the agglomerates. be able to.

(3) Attach multiple temperature sensors to the wall of the tower body, determine the temperature difference between the temperature sensor and the temperature sensor installed at the center of the tower body, and set the number of disconnections to the multiple disconnection valves corresponding to each temperature sensor. By attaching a plate and determining the cutting speed of the agglomerates, it is possible to calculate the regression line between the temperature difference and the cutting speed, and based on this, it is possible to find the cutting speed that will give the average value of the temperature difference. can. If the actual cutting speed is larger than this cutting speed, the operation of the cutting valve can be adjusted by that proportion to lower the cutting speed. This can solve the problem of insufficient cooling of the agglomerates caused by the high cutting speed. The same applies to the opposite case. Therefore, by controlling the operation of each cut-off valve, uneven cooling of the granules can be effectively improved.

(4) Since the temperature detection value of the temperature sensor attached to the top of the cooling gas injection part located at the center of the bottom of the tower body is used as a reference for determining the temperature difference, more accurate control is possible.

(5) By treating temperature as a temperature difference, arithmetic processing in the arithmetic unit becomes quick and easy.

(6) Since the regression line is once determined in the computing unit, each cutoff valve and its operation are adjusted, so that the control of the cutoff valves becomes stable and reliable.

(7) Since uneven cooling of the granules can be prevented by controlling each cut-off valve, it is possible to promote downsizing of equipment and improvement of economic efficiency.

(8) Since the cut-off valve can be controlled during normal and transient times using a computing unit, excellent effects such as uniform cooling of the granules can be achieved with higher precision.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing an example of a dry cooling tower for granules, Tate 2.
The figure is a graph showing the rising velocity ratio distribution of the cooling gas in the cooling tower of Fig. 1, the graph showing the descending velocity ratio distribution of the agglomerates in the cooling tower of Fig. 1, and Fig. 4 is the graph of the present invention. FIG. 5 is a connection diagram showing an embodiment of a device used in a method for controlling the cutting of granules in a dry cooling tower according to the present invention; FIG. Cross-sectional view, FIG. 6 is a cross-sectional view of a main part showing another embodiment of a dry cooling tower used in the cutting control method according to the present invention. In the figure, 1 is the tower body, 3 is the outlet, 8 is the cutoff valve, 13.14
is the cutting number sensor, 15, 16.17゜18.19.2
0 is a first temperature sensor, 21 is a cooling gas blowing section, 22 is a second temperature sensor, and 23 is a computing unit. Patent Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinuya Figure 1

Claims (1)

[Claims] By injecting high-temperature granules from the top of the column and gradually cutting them out from the bottom, a downward moving layer of granules is formed within the column, and cooling gas is blown from the bottom of the column to remove the moving layer. In a dry cooling method in which the granules are cooled and discharged by countercurrent flow, a plurality of discharge ports are provided at the bottom of the tower body for discharging the cooled granules, and a cut-off valve is installed at each discharge port, Each cut-off valve is equipped with a cut-out number sensor that detects the number of times the agglomerate is cut out, and a plurality of first and third temperature sensors are attached to the wall of the column body corresponding to each outlet, and A second temperature sensor is attached to the top of the cooling gas blowing section located, and the cutting number sensor and temperature sensor are electrically connected to the calculator, and the temperature is measured within a certain period of time from the cutting number signal. The first cutting speed is calculated by calculating the amount of agglomerates cut out at , and the temperature difference of the agglomerates near the wall with respect to the center of the tower is calculated from the first temperature signal and the second temperature signal. A regression line of the agglomerate cutting speed with respect to the temperature difference is calculated from the correlation between 1. A method for controlling the cutting of grain in a dry cooling tower for grain agglomerates, characterized in that the interval of operation of each cut-off valve is changed according to the ratio of two cutting speeds, so that the grain agglomerates are cooled to a uniform temperature.