JPH0369570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to equipment for treating exhaust gases containing acid gases, nitrogen oxides, and soot.

Conventional treatment equipment for exhaust gas containing acid gases (e.g., HCl, SOx, etc.), nitrogen oxides (e.g., NOx, etc.), soot, etc. from incinerators for municipal waste, industrial waste, etc. is shown in Figure 1. As shown in the figure, the devices for soot and dust collection, acid gas removal, and nitrogen oxide removal are located independently within the entire plant and are controlled independently, making operations complicated and processing performance depending on each device. Conditional fluctuations influence each other. Further, the auxiliary equipment is also complicated because the reaction products after treatment are discharged from each equipment. In Figure 1, 1 is an incinerator, 2 is a denitrification agent injection device, 3 is a gas cooling device,
4 is an electrostatic precipitator, 5 is an acid gas removal device, 6
indicates the ventilation device. Therefore, if the exhaust gas treatment equipment could be implemented in a single facility, the entire incineration plant would be extremely simple and easy to maintain and manage.

The present invention has been completed to meet such requirements. That is, an object of the present invention is to provide a treatment facility for exhaust gas containing acid gases, nitrogen oxides, and soot.
A superfilter, a primary superlayer formed by coating a nitrogen oxide reduction catalyst on the superfilter, and a secondary superlayer formed by collecting an acidic gas absorbent on the primary superlayer. , a contact type exhaust gas treatment device that passes the exhaust gas in the reverse order of the above, and a chemical injection device that injects a nitrogen compound such as ammonia and an acid gas absorbent such as slaked lime into the exhaust gas duct on the upstream side of the treatment device. An object of the present invention is to provide processing equipment for exhaust gas containing acid gases, nitrogen oxides, and soot, which is characterized by: According to the present invention, the exhaust from the incinerator is discharged from the contact type exhaust gas treatment device in a completely dry manner, so that the ancillary equipment can be greatly simplified.

Next, the equipment of the present invention will be explained with reference to the drawings.

FIG. 2 is a system diagram incorporating the equipment of the present invention. The exhaust gas emitted from the incinerator 11 is guided to the gas cooling device 12 and cooled to a temperature suitable for exhaust gas treatment, and then treated with chemicals from the chemical injection device 13, that is,
Contact type exhaust gas treatment device 14 together with nitrogen compounds such as ammonia and acidic gas absorbents such as slaked lime
I can lead you to. The exhaust gas treated by the exhaust gas treatment device 14 is led to the exhaust device 15 and then discharged into the air. The contact type exhaust gas treatment device 14 has a passing mechanism as shown in FIG. That is, the filter mechanism includes a filter filter 21, a primary filter layer 22 formed by coating the filter with a nitrogen oxide reduction catalyst, and a primary filter layer 22 formed by collecting an acidic gas absorbent on the primary filter layer. secondary superlayer 2
It consists of 3. Then, the exhaust gas whose temperature has been lowered to an appropriate temperature by the gas cooling device 12 is transferred to the chemical injection device 13.
It is introduced into the exhaust gas treatment device 14 from the secondary filter layer 23 side together with chemicals (for example, slaked lime and ammonia) from the filter, and is discharged from the filter filter 21 side.

The overfilter collects soot and chemicals in the exhaust gas, and forms an overcake layer against the exhaust gas. Acidic gases such as sulfur dioxide and hydrogen chloride are absorbed by absorbents such as slaked lime in chemicals, and nitrogen oxides such as NOx are reduced and rendered harmless by the reduction catalyst coated on the superfilter and nitrogen compounds such as ammonia in the chemicals. It is structured to be
The overfilter is provided to hold the overlayer, and can be selected as appropriate depending on the operating temperature.For example, heat-resistant nylon, glass fiber, etc. can be used in the form of woven fabric or felt according to its characteristics. can. A known reduction catalyst can be applied on a superfilter in advance, but by feeding a fine powder of reducing catalyst onto the superfilter in the form of a mixture with air and collecting it, and repeating this process, the primary superlayer can be applied. can also be formed. In this primary overlayer, nitrogen compounds such as ammonia supplied by the chemical injection device are adsorbed, efficiently react with nitrogen oxides in the exhaust gas, and are reduced to harmless nitrogen gas. On the other hand, if the catalyst loses its activity,
A primary overlayer is formed by cleaning and precoating again.

Furthermore, in order to remove acidic gases, an absorbent such as slaked lime supplied by a chemical injection device is collected on the primary overlayer to form a filter cake layer of the absorbent, that is, a secondary overlayer. . In the secondary overlayer, the absorbent and the acidic gas are efficiently reacted and absorbed. Furthermore, soot and dust in the exhaust gas is also passed through this secondary layer. The secondary overlayer becomes impossible for gas to pass through due to an increase in pressure loss, but it can be regenerated by back air cleaning or the like when the pressure loss reaches a certain level.

As described above, according to the equipment of the present invention, exhaust gas containing acid gases, nitrogen oxides, soot, etc. is first absorbed in the secondary overlayer, and then nitrogen oxides are absorbed in the primary overlayer. is converted into harmless nitrogen gas and water vapor. Therefore, it is an industrially extremely advantageous facility because exhaust gas can be treated with a single facility.

[Brief explanation of drawings]

FIG. 1 is a system diagram of conventional exhaust gas treatment, and FIG. 2 is a system diagram of exhaust gas treatment according to the present invention.
FIG. 3 is a diagram showing the exhaust mechanism of the exhaust gas treatment apparatus of the present invention.

Claims (1)

[Claims] 1. In equipment for treating exhaust gas containing acid gases, nitrogen oxides, and soot, a superfilter, a primary superlayer formed by coating the superfilter with a nitrogen oxide reduction catalyst, and a A contact type exhaust gas treatment device has a secondary layer formed by collecting an acidic gas absorbent, and passes the exhaust gas in the reverse order of the above, and a contact type exhaust gas treatment device has a secondary layer formed by collecting an acidic gas absorbent, and a contact type exhaust gas treatment device that has a secondary layer formed by collecting an acidic gas absorbent and passes the exhaust gas in the reverse order of the above, and a A treatment facility for exhaust gas containing acid gases, nitrogen oxides, and soot, comprising a chemical injection device that injects an acid gas absorbent such as a nitrogen compound and slaked lime.