JP7047488B2 - Exhaust gas treatment equipment and exhaust gas treatment method - Google Patents

Description

The present invention relates to an exhaust gas treatment device and an exhaust gas treatment method containing mercury emitted from various factories such as a waste incinerator, a cement manufacturing factory, a thermal power plant, and a non-ferrous metal smelting factory.

Emissions emitted from cement kiln furnaces and non-ferrous metal smelting furnaces and wastes containing mercury may be contained in the exhaust gas emitted by incinerators in waste incinerators, and are released to the atmosphere as they are. It causes air pollution and becomes a problem. Therefore, it is required to remove mercury in the exhaust gas.

Furthermore, the "Minamata Convention on Mercury" was adopted in 2013, and movements to strengthen mercury management worldwide are underway. After the entry into force of this treaty, measures to curb mercury emissions have been considered for facilities subject to mercury emission restrictions. Facilities subject to mercury emission control include coal-fired power plants, coal-fired boilers, non-ferrous metal smelting facilities, waste incinerator facilities, and cement manufacturing facilities. Under such circumstances, there is an increasing demand for a treatment method for efficiently removing mercury in the exhaust gas discharged from these facilities.

For example, as a general method for removing mercury in exhaust gas discharged from a waste incinerator or a boiler furnace, a bag filter for removing dust in the exhaust gas, a bag filter for guiding the exhaust gas to an electrostatic precipitator, etc. On the other hand, Patent Document 1 knows a method in which powdered and granular activated carbon is blown at an upstream position, mercury is adsorbed on the activated carbon, and the activated carbon adsorbing the mercury is collected together with dust by a bag filter or the like and removed from the exhaust gas. ing.

In addition, a mixed powder in which activated carbon is mixed in advance with slaked lime to neutralize and remove the acid gas in the exhaust gas is prepared, and this mixed powder is blown into the exhaust gas in the duct on the upstream side of the bag filter to combine with the acid gas. A method of collecting and treating the reaction product of acid gas and activated carbon adsorbed with mercury together with dust with a bag filter or the like may be used. Thus, mercury in the exhaust gas is adsorbed by activated carbon and then collected and removed by a bag filter or the like.

JP 2010-221085

Depending on the type of waste incinerated in the incinerator and the type of raw material smelted in the cement kiln furnace and non-ferrous metal smelting furnace, the mercury concentration in the exhaust gas may fluctuate to temporarily increase. There is. Even in this case, in order to keep the concentration of mercury in the exhaust gas discharged from the chimney low, it is necessary to constantly inject a large amount of activated carbon to be blown into the duct, or a mixed powder in which slaked lime and activated carbon are mixed in advance is used. When supplying into the duct, it is necessary to constantly blow a large amount of the mixed powder.

In this way, if a large amount of activated carbon or mixed powder is constantly supplied into the duct assuming a temporarily high mercury concentration, the activated carbon and mixed powder will be excessively supplied in many time zones other than the above-mentioned temporary time zone. As a result of the supply, the amount of activated carbon and mixed powder used becomes large, which causes a problem that the exhaust gas treatment cost increases, and the amount of collected dust and the like becomes large, which causes a problem that the dust removal treatment cost increases.

Further, mercury contained in the exhaust gas discharged from the waste incinerator, the cement kiln furnace, and the non-ferrous metal smelting furnace mainly has two types, mercury chloride and metallic mercury. The adsorption performance of activated carbon on mercury varies depending on the form of mercury in the exhaust gas and the components in the exhaust gas. Oxygen and hydrogen chloride are examples of components in the exhaust gas that affect the mercury adsorption performance of activated carbon.

In view of such circumstances, the present invention can reliably adsorb and remove mercury in exhaust gas, and can supply activated carbon with an appropriate amount of activated carbon even if the concentration of mercury in exhaust gas fluctuates, and also exhaust gas. It is an object of the present invention to provide an exhaust gas treatment apparatus and an exhaust gas treatment method capable of appropriately performing adsorption removal treatment with activated carbon in response to fluctuations in oxygen concentration and hydrogen chloride in the medium.

According to the present invention, the above-mentioned problems are solved by the following exhaust gas treatment device and further by the method thereof.

[Exhaust gas treatment equipment]
The exhaust gas treatment device in the present invention is configured as the following first invention, second invention and third invention, and the above-mentioned problems are solved by any of them. Here, the amount of activated carbon supplied (mg / Nm ³ ) is determined as the weight of activated carbon blown with respect to the flow rate of the treated exhaust gas.

<First invention>
In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
On the downstream side of the furnace and on the upstream side of the dust collector, an oxygen concentration meter that measures the oxygen concentration in the exhaust gas, a hydrogen chloride concentration meter that measures the hydrogen chloride concentration in the exhaust gas, and the activated charcoal supply amount of the activated charcoal supply device. Equipped with a control device to control
The control device sets the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector to the set value or less based on the oxygen concentration measurement value by the oxygen concentration meter and the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter. , An exhaust gas treatment device characterized in that the activated charcoal supply amount is controlled based on a predetermined correspondence relationship between the oxygen concentration measured value and the hydrogen chloride concentration measured value and the activated charcoal supply amount.

<Second invention>
In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration meter that measures the oxygen concentration in the exhaust gas, a hydrogen chloride concentration meter that measures the hydrogen chloride concentration in the exhaust gas, and an upstream mercury concentration in the exhaust gas on the downstream side of the furnace and on the upstream side of the dust collector. Equipped with an upstream mercury concentration meter to measure and a control device to control the amount of activated charcoal supplied by the activated charcoal supply device.
The control device is in the exhaust gas on the downstream side of the dust collector based on the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, and the upstream mercury concentration measurement value by the upstream mercury concentration meter. An exhaust gas treatment device characterized in that the amount of activated charcoal supplied is controlled so that the mercury concentration on the downstream side of the water is set to a set value or less.

<Third invention>
In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration meter that measures the oxygen concentration in the exhaust gas, a hydrogen chloride concentration meter that measures the hydrogen chloride concentration in the exhaust gas, and an upstream mercury concentration in the exhaust gas on the downstream side of the furnace and on the upstream side of the dust collector. It is equipped with an upstream mercury concentration meter to measure, a downstream mercury concentration meter to measure the mercury concentration in the exhaust gas on the downstream side of the dust collector, and a control device to control the activated charcoal supply amount of the activated charcoal supply device.
The control device is the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, the upstream mercury concentration measurement value by the upstream mercury concentration meter, and the downstream mercury concentration measurement value by the downstream mercury concentration meter. Based on the above, an exhaust gas treatment device characterized in that the amount of activated charcoal supplied is controlled so that the concentration of mercury on the downstream side in the exhaust gas on the downstream side of the dust collector is set to a set value or less.

In the first to third inventions, it is preferable that the control device is controlled so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. By such control, the adsorption layer of activated carbon is always formed on the bag filter of the dust collector. Therefore, the adsorption removal action by the above-mentioned adsorption layer formed in advance and the adsorption removal action by the activated carbon blown at that time. As a result, mercury can be quickly and surely adsorbed and removed, and the mercury concentration of the exhaust gas after dust collection can be made sufficiently low. Further, in the second or third invention, when the mercury concentration in the exhaust gas is lower than a predetermined value, it is preferable to control the amount of activated carbon supply so as to keep it at a predetermined minimum value. The activated carbon adsorption layer is always formed on the bag filter of the dust collector, and even when the exhaust gas containing mercury having a concentration higher than the predetermined value is discharged, the adsorption layer is adsorbed by the preformed adsorption layer. The removal action and the adsorption removal action by the activated carbon blown at that time can quickly and surely adsorb and remove mercury, and the mercury concentration of the exhaust gas after dust collection can be made sufficiently low.

Further, in the second or third invention, the control device is activated when the measured value of the upstream mercury concentration by the upstream mercury concentration meter or the measured value of the downstream mercury concentration by the downstream mercury concentration meter is equal to or higher than the predetermined mercury concentration. It is preferable to control the supply amount so as to keep it at a predetermined maximum value. When the mercury concentration rises temporarily and suddenly even though the mercury concentration is not so high as an hourly average, if a large amount of activated carbon is supplied in accordance with this high mercury concentration, the activated carbon will be excessively generated over the subsequent time. The result is that it will be supplied. Such an excessive supply can be prevented by controlling the amount of the activated carbon supply to be maintained at a predetermined maximum value.

Further, in the second or third invention, regarding the increase from the minimum value to the maximum value of the activated carbon supply amount, the control device starts from the value where the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the predetermined minimum value of the activated charcoal supply amount, and after the measured mercury concentration reaches the first predetermined mercury concentration, the mercury As the concentration measurement value increases, the activated charcoal supply amount is linearly increased from the predetermined minimum value, and when the mercury concentration measurement value reaches the second predetermined mercury concentration, the activated charcoal supply amount is supplied to the predetermined maximum value. After the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal can be kept constant at the predetermined maximum value with respect to the increase in the measured mercury concentration.

Further, in the second or third invention, regarding the increase from the minimum value to the maximum value of the activated charcoal supply amount, the control device starts from the value where the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the activated charcoal supply amount which is the first supply amount at the predetermined minimum value, and the measured mercury concentration is the first predetermined mercury. When the concentration is reached, the activated charcoal supply amount is increased stepwise to the predetermined second supply amount, and the activated charcoal supply amount is increased within the range until the measured mercury concentration reaches the second predetermined mercury concentration. The mercury concentration measurement value is kept constant at the second supply amount, and further, when the mercury concentration measurement value reaches the second predetermined mercury concentration, the activated carbon supply amount is increased to the predetermined third supply amount. The amount of activated charcoal supply is repeatedly increased stepwise as the amount of water is increased, and after the amount of activated charcoal supply is increased to a predetermined maximum value, the activated charcoal is increased at the predetermined maximum value with respect to the increase in the measured mercury concentration value. It is also possible to keep the supply constant.

As described above, by increasing the amount of activated carbon supply from the minimum value to the maximum value based on the measured value of mercury concentration in the exhaust gas, the activated carbon supply without any trouble for the supply amount adjustment mechanism of the activated carbon supply device. The amount can be controlled smoothly.

[Exhaust gas treatment method]
The exhaust gas treatment method in the present invention is configured as the following fourth invention, fifth invention and sixth invention, and the above-mentioned problems are solved by any of them.

<Fourth invention>
In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. It is equipped with a hydrogen chloride measurement step that measures the amount of hydrogen chloride with a hydrogen chloride concentration meter and a control step that controls the amount of activated charcoal supply of the activated charcoal supply device with a control device.
In the control process, the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector should be set to the set value or less based on the oxygen concentration measured value by the oxygen concentration meter and the hydrogen chloride concentration measured value by the hydrogen chloride concentration meter. , An exhaust gas treatment method characterized by controlling the amount of activated carbon supply.

<Fifth invention>
In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. Hydrogen chloride concentration measurement step that measures the upstream mercury concentration in the exhaust gas on the downstream side of the furnace and upstream side of the dust collector, and the upstream mercury concentration measurement step that measures the upstream mercury concentration in the exhaust gas with the upstream mercury concentration meter. And, it is equipped with a control process that controls the amount of activated charcoal supplied by the activated charcoal supply device with a control device.
In the exhaust gas on the downstream side of the dust collector, based on the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, and the upstream mercury concentration measurement value by the upstream mercury concentration meter in the control step. An exhaust gas treatment method characterized in that the amount of activated carbon supplied is controlled so that the mercury concentration on the downstream side of the water is set to a set value or less.

<Sixth invention>
In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. The hydrogen chloride concentration measurement step that measures the mercury concentration in the exhaust gas on the downstream side of the furnace and the upstream side of the dust collector, and the upstream mercury concentration measurement step that measures the mercury concentration in the exhaust gas with the upstream mercury concentration meter. It is equipped with a downstream mercury concentration measuring step that measures the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector with a downstream mercury concentration meter, and a control step that controls the activated charcoal supply amount of the activated charcoal supply device with the control device.
In the control process, the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, the upstream mercury concentration measurement value by the upstream mercury concentration meter, and the downstream mercury concentration measurement value by the downstream mercury concentration meter Based on this, an exhaust gas treatment method characterized in that the amount of activated charcoal supplied is controlled so that the concentration of mercury on the downstream side in the exhaust gas on the downstream side of the dust collector is set to a set value or less.

In the fourth to sixth inventions, in the control step, it is preferable to control the amount of activated carbon supply so as to be maintained at a predetermined minimum value or more. By such control, the adsorption layer of activated carbon is always formed on the bag filter of the dust collector. Therefore, the adsorption removal action by the above-mentioned adsorption layer formed in advance and the adsorption removal action by the activated carbon blown at that time. As a result, mercury can be quickly and surely adsorbed and removed, and the mercury concentration of the exhaust gas after dust collection can be made sufficiently low. Further, in the fifth or sixth invention, when the mercury concentration in the exhaust gas is lower than the predetermined value, it is preferable to control the amount of activated carbon supply to be maintained at the predetermined minimum value. The activated carbon adsorption layer is always formed on the bag filter of the dust collector, and even when the exhaust gas containing mercury having a concentration higher than the predetermined value is discharged, the adsorption layer is adsorbed by the preformed adsorption layer. The removal action and the adsorption removal action by the activated carbon blown at that time can quickly and surely adsorb and remove mercury, and the mercury concentration of the exhaust gas after dust collection can be made sufficiently low.

Further, in the fifth or sixth invention, in the control step, when the mercury concentration measured by the upstream mercury concentration meter or the downstream mercury concentration meter is equal to or higher than the predetermined mercury concentration, the activated charcoal supply amount is maintained at the predetermined maximum value. It is preferable to control such a method. When the mercury concentration rises temporarily and suddenly even though the mercury concentration is not so high as an hourly average, if a large amount of activated carbon is supplied in accordance with this high mercury concentration, the activated carbon will be excessively generated over the subsequent time. The result is that it will be supplied. Such an excessive supply can be prevented by controlling the amount of the activated carbon supply to be maintained at a predetermined maximum value.

Further, in the fifth or sixth invention, regarding the increase from the minimum value to the maximum value of the activated carbon supply amount, the control step starts from the value where the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the predetermined minimum value of the activated charcoal supply amount, and after the measured mercury concentration reaches the first predetermined mercury concentration, the mercury As the concentration measurement value increases, the activated charcoal supply amount is linearly increased from the predetermined minimum value, and when the mercury concentration measurement value reaches the second predetermined mercury concentration, the activated charcoal supply amount is supplied to the predetermined maximum value. After the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal can be kept constant at the predetermined maximum value with respect to the increase in the measured mercury concentration.

Further, in the fifth or sixth invention, regarding the increase from the minimum value to the maximum value of the activated carbon supply amount, the control step starts from the value where the measured mercury concentration of the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the activated charcoal supply amount which is the first supply amount at the predetermined minimum value, and the measured mercury concentration is the first predetermined mercury concentration. When it reaches, the amount of activated charcoal supply is increased stepwise to the predetermined second supply amount, and the amount of activated charcoal supply is increased to the range until the measured mercury concentration reaches the second predetermined mercury concentration. In addition, when the measured mercury concentration reaches the second predetermined mercury concentration, the activated carbon supply is increased to the predetermined third supply. The amount of activated charcoal supplied is repeatedly increased in a stepwise manner as the amount increases, and after the amount of activated charcoal supply is increased to a predetermined maximum value, the activated charcoal is supplied at the predetermined maximum value with respect to the increase in the measured mercury concentration value. You can also try to keep the amount constant.

As described above, by increasing the activated carbon supply amount from the minimum value to the maximum value based on the measured value of the mercury concentration of the exhaust gas, the activated carbon supply amount does not cause a problem for the supply amount adjustment mechanism of the activated carbon supply device. Can be controlled smoothly.

According to the present invention as described above, in the first invention and the fourth invention, the oxygen concentration in the exhaust gas is measured by an oxygen concentration meter on the downstream side of the furnace and on the upstream side of the dust collector, and the hydrogen chloride concentration is measured by hydrogen chloride. By measuring with a densitometer and adjusting the amount of activated charcoal supply based on the measured oxygen concentration and hydrogen chloride concentration, the oxygen concentration in the exhaust gas and the hydrogen chloride concentration in the exhaust gas are adjusted according to the situation. By grasping the removal performance of mercury and adjusting the amount of activated carbon supply in just proportion, the concentration of mercury in the exhaust gas on the downstream side of the dust collector can be kept below the allowable set value.

In the second and fifth inventions, the oxygen concentration in the exhaust gas is measured with an oxygen concentration meter and the hydrogen chloride concentration is measured with a hydrogen chloride concentration meter on the downstream side of the furnace and upstream of the dust collector, and the upstream side. The side mercury concentration is measured with an upstream mercury concentration meter, and the amount of activated charcoal supplied is adjusted based on the measured value so that the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector is below the allowable set value. When the oxygen concentration and hydrogen chloride concentration in the exhaust gas from the furnace fluctuate, the performance of removing mercury in the exhaust gas by activated charcoal is grasped based on the oxygen concentration measurement value and the hydrogen chloride concentration measurement value, and the mercury concentration in the exhaust gas is further increased. If it fluctuates, the upstream mercury concentration can be measured before the exhaust gas flows into the dust collector, and the amount of activated carbon supply can be quickly adjusted to an appropriate amount based on the measured value. The mercury concentration in the exhaust gas discharged from the chimney can be surely set to the allowable set value or less without causing a delay.

Further, in the third invention and the sixth invention, the oxygen concentration in the exhaust gas is measured by an oxygen concentration meter and the hydrogen chloride concentration is measured by a hydrogen chloride concentration meter on the downstream side of the furnace and upstream of the dust collector. In addition to measuring the side mercury concentration with the upstream mercury densitometer, the downstream mercury concentration is also measured with the downstream mercury densitometer on the downstream side of the dust collector, and the amount of activated charcoal supplied is adjusted based on these four measured values. The downstream mercury concentration on the downstream side of the dust collector shall be less than or equal to the allowable set value. When the oxygen concentration and hydrogen chloride concentration in the exhaust gas from the furnace fluctuate, the performance of removing mercury in the exhaust gas by activated charcoal is grasped based on the oxygen concentration measurement value and the hydrogen chloride concentration measurement value, and further downstream from the furnace. The amount of activated charcoal supplied is controlled based on the measured value of the mercury concentration on the upstream side on the upstream side of the dust collector and the measured value of the mercury concentration on the downstream side on the downstream side of the dust collector. By doing so, it is possible to more reliably reduce the mercury concentration in the exhaust gas discharged from the chimney to the allowable set value or less without delaying the fluctuation of the oxygen concentration and the hydrogen chloride concentration and the fluctuation of the mercury concentration. ..

In the first invention and the fourth invention, the mercury concentration in the exhaust gas from the furnace is controlled by grasping the removal performance of mercury in the exhaust gas by the activated carbon based on the measured oxygen concentration and the measured hydrogen chloride concentration. When it fluctuates, there may be a delay in adjusting the amount of activated carbon supply due to the fluctuation. On the other hand, in the second invention and the fifth invention, since the mercury concentration on the upstream side is measured on the upstream side of the dust collector, the above fluctuation can be quickly dealt with. Further, in the third invention and the sixth invention, the mercury concentration on the upstream side is measured on the upstream side of the dust collector, and the mercury concentration on the downstream side is measured on the downstream side of the dust collector. By adjusting the amount of activated charcoal supplied based on this, the mercury concentration in the exhaust gas discharged from the chimney can be more reliably reduced to the allowable set value or less without delaying the fluctuation of the mercury concentration in the exhaust gas.

Thus, according to the present invention, the oxygen concentration and the hydrogen chloride concentration in the exhaust gas are measured at the position on the upstream side of the dust collector, or the oxygen concentration and the hydrogen chloride concentration are measured on the upstream side of the dust collector and upstream. Oxygen is also measured by measuring the side mercury concentration, or measuring the oxygen concentration and hydrogen chloride concentration on the upstream side of the dust collector, and measuring the upstream mercury concentration on the upstream side of the dust collector and the downstream mercury concentration on the downstream side. Based on the temperature measurement value and the hydrogen chloride concentration measurement value, the performance of removing mercury in the exhaust gas by the activated charcoal is grasped, and the supply amount of the activated charcoal to be blown in is adjusted, so that the mercury concentration in the exhaust gas discharged from the chimney is surely tolerated. The value will be less than the set value, and the activated charcoal will be supplied in just proportion, so that the amount of activated charcoal used can be suppressed and the exhaust gas treatment cost can be reduced.

Further, according to the present invention, the hydrogen chloride concentration and the upstream mercury concentration as the oxygen concentration and the hydrogen chloride concentration in the exhaust gas or the oxygen concentration in the exhaust gas are measured on the upstream side of the dust collector, and the activated carbon is blown based on the measured values. Even if the oxygen concentration and hydrogen chloride concentration in the exhaust gas are low and the mercury adsorption efficiency by the activated charcoal is lowered, the amount of activated charcoal blown in is controlled to be discharged from the chimney. The mercury concentration in the exhaust gas can be reduced to a predetermined value or less. Further, when the measured mercury concentration is equal to or higher than the predetermined mercury concentration, the activated carbon is supplied without excess or deficiency by controlling the amount of activated carbon supply to be maintained at the predetermined maximum value, so that the amount of activated carbon used can be adjusted appropriately. At the same time, it is possible to reduce the exhaust gas treatment cost.

The first embodiment apparatus of this invention is shown, (A) is the schematic block diagram, (B) is the schematic block diagram of the activated carbon supply apparatus. It is a schematic block diagram of the 2nd Embodiment apparatus of this invention. It is a schematic block diagram of the 3rd Embodiment apparatus of this invention. (A) to (H) show various patterns that can be adopted as the relationship between the mercury concentration in the exhaust gas and the amount of activated carbon supplied. It is a figure which shows the relationship between the oxygen concentration, the hydrogen chloride concentration, and the amount of activated carbon supply.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the present embodiment, an incinerator that incinerates waste is described as a furnace that discharges exhaust gas containing mercury, but the present invention is not limited to this, and various types such as a cement kiln furnace and a non-ferrous metal smelting furnace are described. It can be used as a treatment device and a treatment method for exhaust gas containing mercury discharged from a furnace.

By blowing activated carbon into the exhaust gas flow path at the upstream position of the bag filter installed for dust collection for the exhaust gas from the incinerator that incinerates the waste, the activated carbon adsorbs the mercury floating in the exhaust gas flow path. At the same time, an activated carbon layer is created on the surface of the filter material of the bag filter, and mercury is adsorbed by the activated carbon layer to adsorb and remove the mercury in the exhaust gas to suppress the mercury concentration on the downstream side of the bag filter to a low concentration level. However, in the past, due to fluctuations in the type and amount of waste, the morphology and mercury concentration in the exhaust gas from the incinerator fluctuated, and the mercury concentration temporarily increased on the downstream side of the bag filter. In preparation for the case, it is necessary to inject a large amount of activated carbon at all times, which increases the cost of treating exhaust gas.

Therefore, in the present embodiment, an oxygen concentration meter, a hydrogen chloride concentration meter or an oxygen concentration meter, a hydrogen chloride concentration meter, and a mercury concentration meter are installed on the upstream side from the position where the activated charcoal is blown in the exhaust gas flow path on the upstream side of the bag filter. Oxygen concentration and hydrogen chloride concentration or oxygen concentration and hydrogen chloride concentration and mercury concentration are measured, and the amount of activated carbon to be blown is controlled based on the measured oxygen concentration and hydrogen chloride concentration or oxygen concentration and hydrogen chloride concentration and mercury concentration. It is blowing into the exhaust gas flow path. Oxygen densitometers and hydrogen chloride densitometers and mercury densitometers are preferably in the form of continuous measurement.

<First Embodiment>
In FIG. 1A showing an outline configuration of the apparatus of the present embodiment, a boiler 2 is arranged from the upstream side and a bag filter 3 as a dust collecting device in the exhaust gas flow path A that guides the exhaust gas from the incinerator 1 to the chimney 4. An activated carbon supply device 5 for blowing activated carbon for adsorbing and removing mercury in the exhaust gas and a control device 6 for controlling the activated carbon are provided in the exhaust gas flow path A at the upstream position of the bag filter 3. An oxygen concentration meter 7 that measures the oxygen concentration in the exhaust gas at a position upstream of the activated carbon blowing position by the activated carbon supply device 5 on the upstream side of 3 and hydrogen chloride that measures the hydrogen chloride concentration immediately downstream thereof. The oxygen concentration meter 7 and the hydrogen chloride concentration meter 8 are provided with the densitometer 8 so that the measured values of the oxygen concentration meter 7 and the hydrogen chloride concentration meter 8 are sent to the control device 6 as an output signal. It is connected to the.

The measured value of the oxygen concentration meter 7 and the measured value of the hydrogen chloride concentration meter 8 are sent to the control device 6, and the activated carbon supply device 5 is controlled based on the measured value.

The control device 6 stores a predetermined correspondence relationship between the oxygen concentration measured value by the oxygen concentration meter 7 and the hydrogen chloride concentration measured value by the hydrogen chloride concentration meter 8 and the amount of activated charcoal supplied, and based on this correspondence relationship, the activated charcoal is used. The supply amount may be controlled.

Specifically, as shown in FIG. 1B, the activated carbon supply device 5 includes a hopper 5A for accommodating activated carbon, a rotary type cutting member 5B provided at a lower outlet of the hopper 5A, and further. It has a valve or damper 5C provided below it. In the activated carbon supply device 5, at least one of the rotation speed of the rotary of the cutting member 5B, the opening degree of the valve, and the opening degree of the damper 5C is adjusted in response to the command signal from the control device 6, and the amount of activated carbon supplied is adjusted. It is supplied to the exhaust gas flow path A.

<Explanation of the correspondence between the measured oxygen concentration and the measured hydrogen chloride concentration and the amount of activated carbon supplied>
The procedure for determining the correspondence between the measured oxygen concentration and the measured hydrogen chloride concentration and the amount of activated carbon supplied is shown below.

An experiment was conducted in which mercury in the exhaust gas was adsorbed and removed with activated carbon using the exhaust gas treatment device shown in FIG. The upstream mercury concentration in the exhaust gas in the exhaust gas flow path A on the upstream side of the bag filter 3 is almost constant at about 200 μg / Nm ³ , and the oxygen concentration is 4 vol% or less, 4 to 8 vol%, and 8 vol% or more. The hydrogen chloride concentration in the exhaust gas is changed in the range of 50 to 400 ppm, and the above three types of oxygen concentration are in the exhaust gas in the chimney 4 on the downstream side of the bag filter 3 in the case of various hydrogen chloride concentrations. The amount of activated charcoal supply required to keep the concentration of mercury on the downstream side of the slag below 50 μg / Nm ³ or less on average for one hour was obtained, and the preferable correspondence between the oxygen concentration in the exhaust gas, the hydrogen chloride concentration, and the activated charcoal supply amount is shown in FIG. It was decided as shown in.

As shown in FIG. 5, when the oxygen concentration is as high as 8 vol% or more, the mercury removal performance of the activated carbon is high and mercury is sufficiently adsorbed and removed. Therefore, the amount of activated carbon supplied is 4 to 8 vol%. Compared with the case of 4 vol% or less, mercury can be sufficiently removed with a smaller supply amount, and the mercury concentration in the exhaust gas can be sufficiently set to be less than the allowable set value. On the other hand, when the oxygen concentration is low, the ability of activated carbon to adsorb and remove mercury in the exhaust gas is low, so a large amount of activated carbon supply is required, and the amount of activated carbon supply is increased to allow the mercury concentration in the exhaust gas. Try to be less than or equal to the value. That is, the lower the oxygen concentration, the larger the required amount of activated carbon supplied.

Further, as shown in FIG. 5, in any of the above three oxygen concentrations, when the hydrogen chloride concentration is high, the performance of adsorbing and removing mercury in the exhaust gas by activated carbon is high, and the activated carbon sufficiently adsorbs and removes mercury. Will be done. For example, when the oxygen concentration is 8 vol% or more and the hydrogen chloride concentration is 300 ppm or more, the performance of adsorbing and removing mercury in the exhaust gas by the activated carbon is high, and the activated carbon sufficiently adsorbs and removes the mercury. Mercury can be sufficiently removed at about / ^Nm3 , and the mercury concentration in the exhaust gas can be set to a sufficiently acceptable set value or less. On the other hand, when the hydrogen chloride concentration is lower than 300 ppm, the performance of adsorbing and removing mercury in the exhaust gas by activated carbon is low, so a large amount of activated carbon supply is required, and the amount of activated carbon supply is increased to allow the mercury concentration in the exhaust gas. It should be less than or equal to the set value to be set. That is, the lower the hydrogen chloride concentration, the larger the required amount of activated carbon supply.

Even when the mercury concentration in the exhaust gas is different, the measured oxygen concentration and the hydrogen chloride concentration in the exhaust gas have a favorable correspondence between the measured oxygen concentration and the hydrogen chloride concentration, and the measured oxygen concentration and the hydrogen chloride concentration are measured. The amount of activated charcoal supplied by the activated charcoal supply device is controlled based on the measured values.

<Second embodiment>
The second embodiment shown in FIG. 2 has a position upstream of the activated carbon blowing position by the activated carbon supply device 5 in addition to the oxygen densitometer 7 and the hydrogen chloride densitometer 8 as compared with the first embodiment described above. It is the same as the case of FIG. 1 except that the upstream mercury densitometer 9 is installed in. Therefore, in FIG. 2, the same reference numerals are given to the parts common to the parts in the first embodiment of FIG. 1, and the description thereof will be omitted.

In the present embodiment, as seen in FIG. 2, the upstream mercury concentration meter 9 is on the downstream side of the incinerator 1 and on the upstream side of the bag filter 3, and is upstream of the activated carbon blowing position by the activated carbon supply device 5. It is arranged so as to measure the mercury concentration on the upstream side in the exhaust gas at the position on the side. In the present embodiment, the relationship between the oxygen concentration and the hydrogen chloride concentration at the measurement position, the upstream mercury concentration and the activated charcoal supply amount, and the downstream mercury concentration at the downstream position from the bag filter 3 is accumulated based on the accumulated data. It is grasped. Therefore, the oxygen concentration, the hydrogen chloride concentration, and the upstream mercury concentration measured on the upstream side of the activated charcoal blowing position are measured, and the oxygen measured value, the hydrogen chloride concentration measured value, the upstream mercury concentration measured value, and the upstream mercury concentration measured value are supplied at that time. The downstream mercury concentration downstream of the bag filter 3 can be estimated from the amount of activated charcoal supplied. That is, the control device 6 estimates the downstream mercury concentration on the downstream side of the bag filter 3 based on the oxygen concentration, the hydrogen chloride concentration, and the upstream mercury concentration measured value on the upstream side of the activated carbon blowing position. The amount of activated carbon supplied to keep the estimated downstream mercury concentration below the set value can be obtained, and the amount of activated carbon supplied by the activated carbon supply device 5 is controlled. As a result, the downstream mercury concentration on the downstream side of the bug filter 3 is set to be equal to or less than the set value. The control device 6 is supplied at the time of controlling the oxygen concentration measured value by the oxygen concentration meter 7, the hydrogen chloride concentration measured value by the hydrogen chloride concentration meter 8, and the upstream mercury concentration measured value by the upstream mercury concentration meter 9. The amount of activated carbon supply may be controlled based on a predetermined correspondence with the amount of activated carbon supply.

In the present embodiment, when there is a change in the oxygen concentration, the hydrogen chloride concentration, or the mercury concentration in the exhaust gas from the incinerator 1, the change in the oxygen concentration, the hydrogen chloride concentration, or the mercury concentration is transferred to the downstream side of the incinerator 1. The oxygen concentration meter 7, the hydrogen chloride concentration meter 8 and the upstream mercury concentration meter 9 measure and detect at a position upstream of the activated charcoal injection position by the activated charcoal supply device 5, and promptly adjust the activated charcoal supply amount. Therefore, there is no time lag, and the mercury concentration in the exhaust gas on the downstream side of the bag filter 3 can be reliably maintained below the set value. In the example shown in FIG. 2, the measurement position of the oxygen concentration and the hydrogen chloride concentration by the oxygen concentration meter 7 and the hydrogen chloride concentration meter 8 and the measurement position of the upstream mercury concentration by the upstream mercury concentration meter 9 are the activated carbon blowing positions. It is on the upstream side, but is not limited to this, and may be on the upstream side of the bag filter 3 and on the downstream side of the activated carbon blowing position.

Various forms can be applied as a correspondence relationship in which the amount of activated carbon supplied corresponds to a change in the measured value of mercury concentration.

If the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value or lower than the predetermined value, the activated charcoal is not supplied and the mercury concentration in the exhaust gas is zero or the measurable limit minimum value. Alternatively, if the value is higher than a predetermined value, the amount of activated charcoal may be gradually increased as the mercury concentration in the exhaust gas increases (form 1). Further, in addition to the above-mentioned form 1, the amount of activated charcoal supplied is increased as the mercury concentration increases until the measured value of the mercury concentration reaches a predetermined mercury concentration, and the measured value of the mercury concentration is the predetermined mercury. When the concentration is equal to or higher than the concentration, the activated carbon supply amount may be a predetermined maximum value supply amount and may be a form of correspondence (form 2) in which the supply amount is constant. Further, in the first form or the second form, when the amount of activated carbon supplied is increased as the mercury concentration increases, it may be increased linearly or stepwise.

In addition, as a correspondence relationship in which the amount of activated charcoal supplied corresponds to the change in the measured value of mercury concentration, when the measured value of mercury concentration is equal to or less than the predetermined mercury concentration, the amount of activated charcoal supplied is set to the predetermined minimum value, and the measured value of mercury concentration is set. When the mercury concentration is higher than the predetermined mercury concentration, the amount of activated charcoal supplied is gradually increased from the predetermined minimum value as the measured mercury concentration increases, and when the measured mercury concentration is higher than the predetermined mercury concentration, the activated charcoal is supplied. It may be in the form of a correspondence relationship (form 3) in which the amount is maintained at a predetermined maximum value. As the minimum value of the amount of activated carbon supplied, even if the concentration of mercury in the exhaust gas is extremely low during operation when the exhaust gas is discharged from the incinerator 1, by constantly injecting activated carbon with this minimum amount of supply. , Determine the value of the amount of activated carbon supplied to ensure that the concentration of mercury in the exhaust gas in the chimney is maintained below the set value. By gradually increasing the amount of activated carbon supplied from a predetermined minimum value as the measured value of mercury concentration increases, it is possible to supply an appropriate amount of activated carbon with respect to the concentration of mercury in the exhaust gas. When the amount of activated carbon supply is gradually increased from a predetermined minimum value, it may be increased linearly, or it may be divided into a plurality of steps and increased in steps, and various forms of correspondence are adopted. can.

As a means for adjusting the supply amount of activated carbon, the rotation speed of the rotary of the rotary type cutting member of the activated carbon supply device, the opening degree of the valve, the opening degree of the damper, etc. are adjusted individually or in combination. It is preferable to adopt a form of correspondence suitable for the adjustment range of the mechanism and the characteristics of adjustment (for example, the supply amount can be continuously increased or decreased, or can be gradually increased or decreased).

FIG. 4 shows examples of various application forms for Form 3 among the forms of the correspondence between the measured mercury concentration value and the amount of activated carbon supplied.

In the application mode shown in FIG. 4A, the measured value of the mercury concentration in the exhaust gas is zero or a value less than the measurable limit minimum value, and the predetermined minimum value of the activated carbon is in the range from the predetermined mercury concentration to the predetermined value. Activated charcoal is supplied based on the supply amount, and when the measured value of mercury concentration reaches the predetermined mercury concentration, the amount of activated charcoal supply is increased stepwise to the predetermined maximum value, and the mercury concentration in the exhaust gas is further increased. It is a form in which the amount of activated carbon supplied is kept constant at a predetermined maximum value with respect to the increase in the amount of mercury. When the measured value of the mercury concentration is lower than the predetermined mercury concentration, the activated carbon supply amount is set to the predetermined minimum value, and when the measured value is higher than the predetermined mercury concentration, the activated carbon supply amount is set to the predetermined maximum value. The amount of activated carbon supplied can be controlled by a flexible control mechanism.

In the application mode shown in FIG. 4B, the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value, and the range from reaching the first predetermined mercury concentration is a predetermined minimum. Activated charcoal is supplied based on the value of the activated charcoal supply amount (first supply amount), and when the measured value of the mercury concentration reaches the above-mentioned first predetermined mercury concentration, the activated charcoal supply amount is determined in a stepwise manner. It was increased to the second supply amount, the activated charcoal supply amount was kept constant at the second supply amount against the increase of the mercury concentration in the exhaust gas, and the measured value of the mercury concentration reached the second predetermined mercury concentration. Occasionally, in order to increase the amount of activated charcoal supply to a predetermined third supply amount, the amount of activated charcoal supply is repeatedly increased in fine steps as the mercury concentration in the exhaust gas increases, and the amount of activated charcoal supply is predetermined. After increasing to the maximum value of, the activated carbon supply amount is kept constant at the predetermined maximum value against the increase of the mercury concentration in the exhaust gas. By increasing the amount of activated carbon supply from a predetermined minimum value to a predetermined maximum value in a stepwise manner as the mercury concentration in the exhaust gas increases, the amount of activated carbon supplied is more appropriate for the mercury concentration in the exhaust gas. It can be controlled to supply.

The application form shown in FIG. 4C is a form in which the amount of activated carbon supplied is linearly increased from a predetermined minimum value as the mercury concentration in the exhaust gas increases. Further, in the application mode shown in FIG. 4 (D), in the range until the measured value of the mercury concentration in the exhaust gas reaches the predetermined mercury concentration, as the mercury concentration in the exhaust gas increases, the value is linear from the predetermined minimum value. When the measured value of mercury concentration reaches the mercury concentration in the above-mentioned predetermined exhaust gas, the activated charcoal supply amount is set to the predetermined maximum value and the activated charcoal supply amount is set to the predetermined maximum value. After increasing to, the amount of activated charcoal supplied is kept constant at a predetermined maximum value against an increase in the concentration of mercury in the exhaust gas. In the application embodiments shown in FIGS. 4C and 4D, the amount of activated carbon supplied is continuously increased from a predetermined minimum value as the mercury concentration in the exhaust gas increases, so that the mercury concentration in the exhaust gas is increased. It is possible to finely control the supply of activated carbon in an appropriate amount.

In the application mode shown in FIG. 4 (E), the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value, and the range from reaching the first predetermined mercury concentration is a predetermined minimum. After the activated charcoal is supplied based on the value of the activated charcoal supply amount and the measured value of the mercury concentration reaches the above-mentioned first predetermined mercury concentration, as the mercury concentration in the exhaust gas increases, the activated charcoal is linearly applied from the predetermined minimum value. When the measured value of the mercury concentration reaches the second predetermined mercury concentration by increasing the activated charcoal supply amount, the activated charcoal supply amount is set to the predetermined maximum value supply amount and the activated charcoal supply amount is increased to the predetermined maximum value. After that, the amount of activated charcoal supplied is kept constant at a predetermined maximum value against an increase in the concentration of mercury in the exhaust gas. The application form shown in FIG. 4 (E) is a combination of the application forms shown in FIGS. 4 (A) and 4 (C), and has the characteristics and effects of each form.

In the application mode shown in FIG. 4 (F), the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value, and the range from reaching the first predetermined mercury concentration is a predetermined minimum. Activated charcoal is supplied based on the value of the activated charcoal supply amount (first supply amount), and after the measured value of the mercury concentration reaches the above-mentioned first predetermined mercury concentration, as the mercury concentration in the exhaust gas increases, the first The amount of activated carbon supply is increased linearly from one supply amount to a second supply amount corresponding to the second predetermined mercury concentration, and then the activated charcoal supply amount is increased in response to the increase in the mercury concentration in the exhaust gas. The third supply amount is kept constant, and when the third predetermined mercury concentration is reached, the activated carbon supply amount is linearly increased from the second supply amount to correspond to the fourth predetermined mercury concentration. After that, the amount of activated charcoal supply is kept constant at the third supply amount in response to the increase in the mercury concentration in the exhaust gas, and the amount of activated charcoal supply is increased in response to such an increase in the mercury concentration in the exhaust gas. After increasing the amount of activated charcoal supply to a predetermined maximum value by repeating keeping it constant and increasing it, the amount of activated charcoal supply is kept constant at the predetermined maximum value against an increase in the mercury concentration in the exhaust gas. It is a form. The application form shown in FIG. 4F is a combination of the application forms shown in FIGS. 4B and 4D, and has the characteristics and effects of each form.

In the application mode shown in FIG. 4 (G), the amount of activated charcoal supplied linearly from a predetermined minimum value as the mercury concentration in the exhaust gas increases until the measured value of the mercury concentration in the exhaust gas reaches the predetermined mercury concentration. When the measured value of the mercury concentration reaches the above-mentioned predetermined mercury concentration, the activated charcoal supply amount is increased to the predetermined maximum value in a stepwise manner, and the activated charcoal supply amount is increased to the predetermined maximum value. Is a form in which the amount of activated charcoal supplied is kept constant at a predetermined maximum value with respect to an increase in the concentration of mercury in the exhaust gas. When the measured value of the mercury concentration in the exhaust gas is lower than the predetermined value, which is relatively medium, the amount of activated charcoal supplied is continuously increased from the predetermined minimum value as the mercury concentration in the exhaust gas increases. It is possible to finely control the supply of activated charcoal in an appropriate amount with respect to the medium mercury concentration, and if the measured value of the mercury concentration in the exhaust gas is higher than the relatively medium predetermined mercury concentration, the activated charcoal supply amount is adjusted. It is a correspondence relationship in which a predetermined maximum value is set, and the activated charcoal supply amount can be controlled by an appropriate amount by effectively utilizing a plurality of means for adjusting the activated charcoal supply amount.

In the application mode shown in FIG. 4 (H), until the measured value of the mercury concentration in the exhaust gas reaches the first predetermined mercury concentration, as the mercury concentration in the exhaust gas increases, the measured value linearly from the predetermined minimum value. When the activated charcoal supply amount is increased and the measured value of the mercury concentration reaches the first predetermined mercury concentration, the activated charcoal supply amount is set as the predetermined first supply amount, and the measured value of the mercury concentration is the second predetermined mercury. Until the concentration is reached, the activated charcoal supply amount is kept constant at the predetermined first supply amount, and when the measured value of the mercury concentration reaches the second predetermined mercury concentration, the activated charcoal supply amount is predetermined in a stepwise manner. After increasing to the maximum value of and increasing the amount of activated charcoal supply to a predetermined maximum value, the activated charcoal supply amount is kept constant at the predetermined maximum value against an increase in the mercury concentration in the exhaust gas. .. The application form shown in FIG. 4 (H) has a predetermined range (from the first predetermined mercury concentration to the second) in which the measured value of the mercury concentration in the exhaust gas is relatively medium in the application form shown in FIG. 4 (G). In the range up to the predetermined silver concentration), the activated carbon supply amount is kept constant at the first predetermined supply amount, and the supply of the activated carbon can be controlled to be supplied in a more appropriate amount.

<Third embodiment>
Compared to the second embodiment described above, the third embodiment shown in FIG. 3 has an oxygen densitometer 7, a mercury densitometer 8, and a hydrogen densitometer 8 arranged on the upstream side of the activated charcoal blowing position by the activated charcoal supply device 5. In addition to the first mercury densitometer (upstream mercury densitometer) 9A, the second mercury densitometer (downstream mercury) that measures the mercury concentration in the exhaust gas at the outlet or chimney 4 of the bag filter 3 on the downstream side of the bag filter 3. Densitometer) 9B is also provided, which is a feature. Other than this point, it is the same as the second embodiment. The measured value of the second mercury densitometer 9B is sent to the control device 6 as an output signal together with the measured values of the oxygen densitometer 7, the hydrogen chloride densitometer 8, and the first mercury densitometer 9A. In FIG. 3, the same reference numerals are given to the parts common to the parts in the second embodiment of FIG. 2, and the description thereof will be omitted.

In this embodiment, as seen in FIG. 3, as described above, as a mercury densitometer, the first is arranged on the upstream side of the activated charcoal blowing position by the activated charcoal supply device 5 of the second embodiment described above. In addition to the mercury densitometer 9A (upstream mercury densitometer), a second mercury densitometer 9B (downstream mercury densitometer) is provided at the outlet of the bag filter 3 or the chimney 4. Similar to the second embodiment, the oxygen concentration by the oxygen concentration meter 7 and the hydrogen chloride concentration by the hydrogen chloride concentration meter 8 and the upstream mercury concentration by the first mercury concentration meter 9A on the upstream side of the activated charcoal blowing position by the activated charcoal supply device 5. The amount of activated charcoal supplied is controlled based on the measured value, and the oxygen concentration by the oxygen concentration meter 7 and the chloride by the hydrogen chloride concentration meter 8 are based on the downstream mercury concentration measurement value by the secondary mercury concentration meter 9B at the outlet of the bag filter 3. The amount of activated charcoal supplied is controlled to be increased or decreased by complementing the control based on the hydrogen concentration and the measured value of the upstream mercury concentration by the first mercury concentration meter 9A.

The set value of the mercury concentration in the exhaust gas at the outlet of the bag filter 3 or the chimney 4 is set in advance, and when the measured value of the mercury concentration on the downstream side by the secondary mercury concentration meter 9B exceeds the set value, the amount of activated carbon supplied is determined. It may be controlled so as to further increase.

By incorporating this control, the mercury concentration at the outlet of the bug filter 3 or the chimney 4 can be controlled to a set value or less more reliably than in the second embodiment.

1 furnace (incinerator)
2 Boiler 3 Dust collector (bug filter)
4 Chimney 5 Activated carbon supply device 6 Control device 7 Oxygen densitometer 8 Hydrogen chloride densitometer 9 Mercury densitometer 9A First mercury densitometer (upstream mercury densitometer)
9B Second Mercury Densitometer (Downstream Mercury Densitometer)

Claims (10)

In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration meter that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and on the upstream side of the dust collector,
Equipped with a hydrogen chloride concentration meter that measures the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector, and a control device that controls the amount of activated carbon supplied by the activated carbon supply device.
The control device sets the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector to the set value or less based on the oxygen concentration measurement value by the oxygen concentration meter and the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter. , An exhaust gas treatment device characterized in that the activated charcoal supply amount is controlled based on a predetermined correspondence relationship between the oxygen concentration measured value and the hydrogen chloride concentration measured value and the activated charcoal supply amount. In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration meter that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and on the upstream side of the dust collector, and hydrogen chloride that measures the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and on the upstream side of the dust collector. It is equipped with a densitometer, an upstream mercury densitometer that measures the upstream mercury concentration in the exhaust gas, and a control device that controls the activated charcoal supply amount of the activated charcoal supply device.
The control device is in the exhaust gas on the downstream side of the dust collector based on the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, and the upstream mercury concentration measurement value by the upstream mercury concentration meter. An exhaust gas treatment device characterized in that the amount of activated charcoal supplied is controlled so that the mercury concentration on the downstream side of the water is set to a set value or less. In an exhaust gas treatment device including a dust collector that removes exhaust gas discharged from a furnace and contains mercury, and an activated carbon supply device that blows activated carbon into an exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration meter that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector, and hydrogen chloride that measures the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. A densitometer, an upstream mercury concentration meter that measures the upstream mercury concentration in the exhaust gas, a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector, and the activated charcoal supply amount of the activated charcoal supply device. Equipped with a control device to control
The control device is the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, the upstream mercury concentration measurement value by the upstream mercury concentration meter, and the downstream mercury concentration measurement by the downstream mercury concentration meter. An exhaust gas treatment device characterized in that the amount of activated charcoal supplied is controlled so that the concentration of mercury on the downstream side in the exhaust gas on the downstream side of the dust collector is set to a set value or less based on the value. The exhaust gas treatment device according to claim 1, wherein the control device is controlled so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. The control device keeps the amount of activated charcoal supplied at the specified maximum value when the measured value of the upstream mercury concentration by the upstream mercury concentration meter or the measured value of the downstream mercury concentration by the downstream mercury concentration meter is equal to or higher than the specified mercury concentration. The exhaust gas treatment apparatus according to claim 2 or claim 3, which is to be controlled. In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. It is equipped with a hydrogen chloride measurement step that measures the amount of hydrogen chloride with a hydrogen chloride concentration meter and a control step that controls the amount of activated charcoal supply of the activated charcoal supply device with a control device.
In the control process, the downstream mercury concentration in the exhaust gas on the downstream side of the dust collector should be set to the set value or less based on the oxygen concentration measured value by the oxygen concentration meter and the hydrogen chloride concentration measured value by the hydrogen chloride concentration meter. , An exhaust gas treatment method characterized by controlling the amount of activated carbon supply. In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. The hydrogen chloride concentration measuring step that measures the hydrogen chloride concentration meter, the upstream mercury concentration measuring step that measures the upstream mercury concentration in the exhaust gas with the upstream mercury concentration meter, and the activated charcoal supply amount of the activated charcoal supply device with the control device. Equipped with a control process to control
In the control process, the exhaust gas on the downstream side of the dust collector is based on the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, and the upstream mercury concentration measurement value by the upstream mercury concentration meter. An exhaust gas treatment method characterized in that the amount of activated carbon supplied is controlled so that the concentration of mercury on the downstream side of the inside is set to a set value or less. In the exhaust gas treatment method in which the exhaust gas discharged from the furnace and containing mercury is dust-removed by the dust collector, and the activated carbon is blown from the activated carbon supply device into the exhaust gas flow path that guides the exhaust gas from the furnace to the dust collector.
An oxygen concentration measurement process that measures the oxygen concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector with an oxygen concentration meter, and the hydrogen chloride concentration in the exhaust gas on the downstream side of the furnace and upstream of the dust collector. The hydrogen chloride concentration measuring step that measures the mercury concentration in the exhaust gas with the hydrogen chloride concentration meter, the upstream mercury concentration measuring step that measures the mercury concentration in the exhaust gas with the upstream mercury concentration meter, and the downstream mercury in the exhaust gas on the downstream side of the dust collector. It is equipped with a downstream mercury concentration measuring step that measures the concentration with a downstream mercury concentration meter and a control step that controls the activated charcoal supply amount of the activated charcoal supply device with a control device.
In the control process, the oxygen concentration measurement value by the oxygen concentration meter, the hydrogen chloride concentration measurement value by the hydrogen chloride concentration meter, the upstream mercury concentration measurement value by the upstream mercury concentration meter, and the downstream mercury concentration measurement value by the downstream mercury concentration meter. Based on the above, an exhaust gas treatment method characterized in that the amount of activated charcoal supplied is controlled so that the concentration of mercury on the downstream side in the exhaust gas on the downstream side of the dust collector is set to a set value or less. The exhaust gas treatment method according to claim 6, wherein the control step is controlled so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. In the control step, when the upstream mercury concentration measurement value by the upstream mercury concentration meter or the downstream mercury concentration measurement value by the downstream mercury concentration meter is equal to or higher than the predetermined mercury concentration, the activated carbon supply amount is maintained at the predetermined maximum value. The exhaust gas treatment method according to claim 7 or claim 8, which is to be controlled.

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