JPH0538416A - Method for operation controlling desulfurization equipment for incinerator at optimum desulfurization efficiency - Google Patents

Abstract

PURPOSE:To provide a method for controlling the amount of sodium hydroxide to be added at the optimum value in desulfurization equipment for removing SOx in an exhaust gas from an incinerator. CONSTITUTION:The amount of sodium hydroxide to be added is controlled at the value determined by the regression curve indicating the relation between the SOx concentration in an exhaust gas after desulfurization and the amount of sodium hydroxide to be added into injected water to attain the desulfurization ratio at 70%. In this way, the amount of sodium hydroxide to be added can be regulated at the optimum value by continuous controlling, so that a sharp increase in SOx in the exhaust gas can be avoided to contribute the saving of sodium hydroxide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to optimum desulfurization work in a desulfurization device for removing SO _X in exhaust gas from an incinerator.

[0002]

2. Description of the Related Art SO in incinerator exhaust gas_XDesulfurization to remove
When performing work, regarding the situation in conventional technology,
The description in Japanese Patent Application Laid-Open No. 3-52621 by the applicant
is there. That is, a gas cooler equipped with a cooling water spray device, a dry
Equipped with a dust collector, heat recovery device, etc.
In the storage, add caustic soda to remove SO
_XIt is a system for removing.

[0003]

However, according to the system described above, the relationship between the amount of NaOH to be added and the optimum desulfurization efficiency cannot be grasped, and it is difficult to improve the desulfurization rate by increasing the amount of NaOH added. However, it was unavoidable to unnecessarily increase the amount of NaOH added.

Exhaust gas is SO _x before cooling desulfurization.
Concentration measurement was dusty, making accurate continuous measurement difficult.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for maintaining an optimum desulfurization efficiency by adding an appropriate amount of NaOH.

[0006]

The operation management method of the optimum desulfurization efficiency in the incinerator desulfurization apparatus according to the present invention is applied to the water to be injected into the exhaust gas cooling apparatus of the waste incinerator in which the SO _X concentration in the exhaust gas changes. In the work of performing desulfurization by adding NaOH, the desulfurization rate is set to 65 in accordance with a regression curve showing a previously investigated and confirmed relationship between the SO _X concentration in the exhaust gas after desulfurization and the amount of NaOH added to the water to be injected. % -75% of the chemical equivalent is added to the water to be injected into the exhaust gas cooling device.
Is added.

[0007]

[Function] There is a certain strong correlation between the concentration of SO _{X in} the exhaust gas after desulfurization and the amount of NaOH added to the water to be injected, and when the desulfurization rate exceeds 70%, the amount of addition of NaOH increases. Since it was confirmed that it was wasted even if the above procedure was performed, the concentration of SO _{x in} the exhaust gas was detected and the desulfurization rate became 70%.
The amount of OH added is determined.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an operation management method for optimum desulfurization efficiency in an incinerator desulfurization apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a flow chart of an apparatus and the like relating to the operation management method according to the present invention. In the figure, 1 is an SO _X concentration meter, which continuously measures the concentration of SO _{X in} the exhaust gas sucked from the exhaust gas flue 4 by the sampling pump 15. The caustic soda pump 3 sucks the above-mentioned exhaust gas, sucks the caustic soda solution from the caustic soda tank 2, and adds it to the cooling water. The cooling water is sucked from the water tank 7 by the cooling water pump 8 and injected into the gas cooler 9 through the cooling water flow rate control adjusting injector 10. Exhaust gas from the incinerator at about 600 ° C. to 800 ° C. is sent to the gas cooler 9 through the exhaust gas duct 11. The exhaust gas is cooled to about 300 ° C. to 400 ° C. in the gas cooler 9 and is desulfurized by the caustic soda added to the cooling water, so that the concentration of SO _X is reduced to about 30%.

In the figure, 5 is a chimney, which discharges the desulfurized exhaust gas into the atmosphere. An exhaust gas suction fan 6 sucks combustion exhaust gas and discharges it into the atmosphere through a chimney. A temperature recording controller 12 measures the inlet temperature of the electrostatic precipitator 13 and issues a command to the cooling water flow rate control adjusting injector 10 so that the gas temperature is cooled to 300 ° C to 400 ° C. 14
Is a waste heat boiler that recovers part of the heat of exhaust gas.

The relationship between the amount of added NaOH and the desulfurization rate at this time has the correlation shown in the graph of FIG. Desulfurization rate The addition of NaOH of equivalent chemical equivalent to twice the chemical equivalent of the street SO _X shown in the graph becomes 70%.
The curve in the graph is the actual value. From the curve of the graph, it can be known that the effect can be obtained by controlling the desulfurization rate in the range of 65% to 75% in consideration of the variation in the actual work.

When the addition amount of the chemical equivalent of NaOH is 1/2 of the chemical equivalent of SO _x , the desulfurization rate becomes 45%. Na
Desulfurization rate in the case the addition amount of equivalents of OH of a chemical reaction is equal to the equivalent of a chemical reaction of SO _X becomes 55%. It has been shown that the effect of improving the desulfurization rate becomes extremely small even if the amount of NaOH added is increased from around the point where the desulfurization rate exceeds 70%. If the amount of the chemical equivalent of NaOH conversely falls below a point corresponding to two times the chemical equivalent of SO _X, since the desulfurization efficiency decreases rapidly, considerable chemical equivalent of NaOH to twice the stoichiometric amount of SO _X Desulfurization rate is 70% when the amount is added
It can be seen that the point where is the optimum amount of NaOH added.

FIG. 3 shows the values obtained in actual operation when the desulfurization rate was 70%. SO in the exhaust gas in the flue on the horizontal axis
The concentration of _X is shown and the amount of NaOH added to the vertical axis is shown. The values obtained in actual operation are along the regression curve in the figure. The mechanism is such that the amount of NaOH added is adjusted according to the regression curve in the figure according to the transition of the concentration of SO _{X in} the exhaust gas in the flue.

As described above, according to the present invention, the desulfurization rate can be controlled to about 70%.

[0014]

According to the present invention, the amount of NaOH to be added can be adjusted so that the SO _{X in} the exhaust gas is always effectively reduced, and since the continuous control is performed, the SO _X in the exhaust gas is controlled. NaOH can be effectively utilized without sudden increase.

[Brief description of drawings]

FIG. 1 is a flowchart of an apparatus and the like related to an operation management method according to the present invention.

FIG. 2 is a graph showing the relationship between the amount of added NaOH and the desulfurization rate according to the present invention.

FIG. 3 shows a desulfurization rate of 70% in the method according to the present invention.
It is explanatory drawing which showed the value obtained by the actual operation in the case of.

[Explanation of symbols]

1 SO _X concentration meter 2 Caustic soda tank 3 Caustic soda pump 4 Exhaust gas flue 5 Chimney 6 Exhaust gas suction fan 7 Water tank 8 Cooling water pump 9 Gas cooler 10 Cooling water flow control adjusting injector 11 Exhaust gas duct 12 Temperature recording controller 13 Electrostatic precipitator 14 Waste heat boiler 15 Sampling pump

Claims (1)

[Claims] 1. In the work of desulfurization by adding NaOH to water to be injected into an exhaust gas cooling device of a waste incinerator where the SO _X concentration in the exhaust gas changes, S in the exhaust gas after desulfurization
According to a regression curve showing the previously investigated and confirmed relationship between the O _X concentration and the amount of NaOH added to the water to be injected, the chemical equivalent to the desulfurization rate of 65% to 75% was applied to the water to be injected into the exhaust gas cooling device. An operation management method for optimum desulfurization efficiency in an incinerator desulfurization device, characterized by adding NaOH.