JPH0735512B2 - Dust control device for gas circulation system in coke dry fire extinguishing system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for suppressing coke dust in a circulating gas system line in a coke dry fire extinguishing facility.

(Prior Art) As is well known, coke dry fire extinguishing equipment is installed mainly for the purpose of recovering sensible heat of red hot coke extruded from a coke oven, that is, waste heat recovery. It is configured as a closed system consisting of a high temperature gas flow path having a primary dust catcher, an exhaust heat recovery boiler, and a circulating gas flow path for low temperature gas supply having a secondary dust catcher. A problem with such equipment is the management of coke dust in the circulating gas. That is, the coke dust, which has a strong wear force, may abrade the heat transfer tube of the boiler, sometimes damage the heat transfer tube, and cause steam ejection troubles. As measures against this, the coke concentration in the gas is reduced to improve the collection efficiency of the dust catcher, the uneven flow of the gas in the boiler, and the increase in the thickness of the entire heat transfer tube to prevent local wear due to segregation. As disclosed in Japanese Patent Publication No. 57-139177, there is a method of connecting two or more cyclones in parallel or series to increase dust removal efficiency.

(Problems to be Solved by the Invention) The concentration of dust contained in the circulating gas changes depending on the following operating conditions. That is, the lower the coke strength input, the higher the dust concentration.

Further, the dust concentration is higher as the gas blanket velocity in the cooling chamber is higher. Furthermore, the dust concentration increases when the red hot coke is charged and when the cooling coke is discharged. On the other hand, in order to quantitatively understand the coke dust concentration in the gas, a method is generally used in which a sampling hole is provided in the gas circulation duct and the gas is sucked at a constant velocity to measure the dust concentration. Yes It is difficult to obtain representative sampling. In addition, the measurement load is high and continuous implementation is not possible. Further, there is a problem that a large error occurs due to the measurement timing at which the dust concentration becomes high when the red hot coke is charged and when the cooling coke is discharged. Therefore, the dust concentration in the gas is hardly controlled, and the actual condition is that the wear heat of the boiler heat transfer tube or blower impeller is only checked once a year.

(Means for Solving the Problem) In view of the above-mentioned circumstances, the present invention provides a device for suppressing the coke dust concentration in the circulating gas, which is characterized in that the projector is orthogonal to the circulating gas passage. And the light receiver are installed to face each other, the light transmittance is continuously measured, and the dust concentration in the gas is detected from the light transmittance, and the signal is used to detect the rotation speed of the gas circulation blower or the cooling gas circulation amount by the damper. Is to suppress and control.

The light transmittance is equivalent to the gas concentration as physical information, as can be seen from the Lamber-Beer law shown below.

μ = I / Io = e ^- kcl (1) where μ: Light transmittance Io: Incident light amount from the projector I: Transmitted light amount to the light receiver K: Constant C: Gas concentration l: Optical path length Concentration meter installation As for the place, it may be installed in the front and rear ducts of the device for abrasion resistance etc. From the point of heat resistance of the measuring equipment, the gas temperature between the primary dust catcher and the boiler inlet is as high as about 800 ° C. Boiler exit and 2
It is preferably installed between the next dust catchers.

As a dust suppression control method, it is difficult to control by the instantaneous value because the dust concentration fluctuates greatly when charging and discharging red hot coke as described above. -It is preferable to perform predictive control by limiting the rotation speed of the blower or the damper when discharging.

In addition, if the gas circulation amount is reduced too much in order to reduce the dust amount too much, the cooling efficiency will decrease too much, so it must be noted. According to the experiment of the present inventor,
If it is reduced by 50%, the cooling efficiency will be reduced by about 10%.

(Operation) By controlling the blowing amount of the cooling gas, it is possible to reduce the above-mentioned empty velocity of the gas in the cooling chamber, and it is possible to reduce the dust concentration that increases when the red hot coke is charged and discharged. Also, since the gas velocity flowing through the circulation duct becomes slower, the efficiency of the primary dust catcher improves,
Furthermore, since the impact force of the coke dust on the boiler heat transfer tube is also reduced, various troubles due to the coke dust are reduced.

(Example) As shown in Fig. 1, the coke dry fire extinguishing equipment is loaded with red hot coke in a bucket 2 lifted by a crane and cooled by a charging hopper 3 through a charging port 4 and a pre-chamber 5a. It is put into the chamber 6.
On the other hand, the inert gas for cooling the red hot coke is pumped by the blower 7, blown from the lower part of the cooling chamber 6 and discharged from the circular chamber 5b and circulated. The discharge gas temperature at this time was 700 to 800 ° C. Coarse coke dust in the gas is collected by the primary dust catcher 9 in the duct 8 of the circulating gas system path and guided to the boiler 10.
After heat exchange in the boiler 10, the gas temperature becomes about 150 ° C., then fine dust is collected by the secondary dust catcher 11 and sucked into the blower 7.

The dust concentration meter 12 was installed between the outlet of the boiler 10 and the secondary dust catcher 11 and in the duct 8. As shown in FIG. 2, the mounting structure is such that a hole is formed in the circulating gas duct 8 and a light projector 12a for generating a light beam and a light receiver 12b having a light receiving element are installed to face each other. A light beam (visible light in this embodiment) is continuously generated from the projector 12a, and its light transmittance is measured by the light receiver 12b.
It was continuously detected at and converted into an electric quantity (concentration when light reaches 100% is 0, and when light reaches 0%, concentration is 10).

In addition, 12c and 12d are blowing ports of purge air for preventing lens contamination of the light projector 12a and the light receiver 12b.

The electric signal of the gas dust concentration thus detected is input to the controller 13, and the controller 13 calculates the average concentration value of 1 hour as 2.
It was set to 0, and the suction damper 14 of the blower 7 was operated to control the cooling gas circulation amount. As shown in FIG. 3, the result shows that the dust concentration can be significantly reduced and controlled in the present embodiment as compared with the dust concentration in the comparative example, which is focused on only the conventional cooling efficiency.

By the way, the dust concentration at this time was 1.7 on average for 3.2 hours.
However, the cooling efficiency was 93.5% due to the reduction of the cooling gas circulation amount.

(Effect of the invention) As described above, according to the present invention, the concentration of the circulating gas for cooling can be continuously measured, and the dust concentration in the circulating gas can be suppressed and controlled by the measurement, so that the heat transfer tube of the boiler or the blower This has the effect of extending the life of the impeller due to wear, improving the collection efficiency of the dust catcher, and enabling stable operation.

[Brief description of drawings]

FIG. 1 is a schematic view showing a coke dry-type fire extinguishing facility and a circulating gas dust concentration control device of the present invention in an embodiment, FIG.
FIG. 3 is a circulating gas dust measuring device in the example, and FIG. 3 is a change diagram of the circulating gas dust concentration in the example. 6 ... Cooling chamber, 7 ... Blower 8 ... Duct, 9 ... Primary dust catcher 10 ... Boiler, 11 ... Secondary dust catcher 12 ... Dust concentration meter, 12a ... Emitter 12b ... Receiver , 13 …… Controller 14 …… Inhalation damper.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 49-5688 (JP, A) Japanese Patent Laid-Open No. 50-97509 (JP, A) Actually published 59-76538 (JP, U)

Claims (1)

[Claims] 1. A closed system comprising a cooling tower main body, a high temperature gas passage having a primary dust catcher, a heat recovery boiler, and a circulating gas passage for supplying a low temperature gas having a secondary dust catcher. In the coke dry fire extinguishing equipment, a device for measuring the light transmittance with the light transmitter and the light receiver facing each other orthogonally to the circulating gas flow path, and a gas of the gas circulation blower rotation speed or a damper depending on the signal of the measuring device. A dust control device for the gas circulation system in a coke dry fire extinguisher system consisting of a device that regulates the amount of circulation.