JPS6071079A - Treatment of washing waste water - Google Patents

Abstract

PURPOSE:To easily treat washing waste water in a system without discharging the same, by charging washing waste water, generated when an exhaust gas treating packing material is washed with water and regenerated, into the gas treating apparatus of a furnace. CONSTITUTION:When an exhaust gas treating packing material such as a catalyst is washed with water and regenerated while a reactor 12 is packed therewith, washing waste water is generated. When this washing waste water is introduced into a gas treating apparatus such as a boiler, an incinerator 2 or a flue 3, it is directly evaporated without discharging same. As mentioned above, washing waste water can be treated in the system easily without discharging the same out of the system for the purpose of treatment and post-treatment is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention regenerates various catalysts that are packed for exhaust gas treatment and whose performance has deteriorated by washing with water.

The present invention relates to a wastewater treatment method in which generated cleaning wastewater is treated within the system.

Urban and industrial waste 1 A denitrification reaction in which exhaust gas from burning coal, oil, etc. is passed through a catalyst to reduce and detoxify nitrogen oxides in the exhaust gas.

- Alkali or alkaline earth metals contained in dust in combustion exhaust gas accumulate in various catalysts applied to reactions that oxidize and burn carbon oxides or hydrocarbons, and their performance deteriorates. Alkali metals such as potassium (Ka), sodium (Na), and magnesium (Mg) can be used as denitrification catalysts,
In catalytic reactions targeting combustion exhaust gas such as combustion catalysts.

It is a poisonous substance that inhibits catalyst activity, and it is desirable to reduce its content as much as possible.

Unlike catalysts used in synthesis reactions, the main purpose of catalysts for exhaust gas treatment is environmental improvement, and no consideration is given to pre-treating the exhaust gas to protect catalyst activity and life. Recently, due to worsening fuel conditions, dust has increasingly become a source of exhaust gas that has an adverse effect on catalysts in terms of dust amount and dust composition, and the catalysts used there are required to be resistant to dust poisoning.

The most suitable denitrification catalyst was developed to reduce and remove the nitrogen oxides contained in the above exhaust gas using ammonia, and the catalyst composition was developed to correspond to each exhaust gas source.

We provide highly active and long-lasting denitrification equipment with different shapes and manufacturing methods, and many practical equipment are already in smooth operation in boilers at thermal power plants and various chemical factories.

In this case, it has SOx resistance and dust blockage resistance for dirty gas containing dust and SOx, such as garbage incinerators, single fuel oil-fired boilers, and coal-fired boilers.

It is necessary to select the optimal catalyst specifications taking into account dust abrasion resistance, etc., and by using TiO2 as a carrier, SOx resistance
Since the properties are sufficient, V2O5°WO3 is added to TiO2.
A catalyst supporting an active component such as 1Fe 2031 Mo03 is used. In addition, as catalyst shapes that do not become clogged with dust, the above-mentioned catalysts shaped into granules, cylinders, elliptical rods, etc. are used in a moving bed, plate shapes, pipe shapes, etc.
Methods of using a fixed bed of catalyst structures such as non-nicum or lattice structures to allow exhaust gas to pass through in parallel have been compared, and now non-nicum catalysts and lattice-shaped catalysts are mainstream because they are economical and easy to maintain. It has become.

The only way to prevent dust components from entering the catalyst and reducing catalyst performance is to soften the effect as much as possible by creating a catalyst composition that allows dust to pass through the catalyst. However, it is important to select active ingredients that can withstand alkali or alkaline earth metals such as Na and Mg, which have a particularly negative effect on performance. have provided. However, the Na content of heavy oil 1 coal depends on where it is extracted.

The Mg content is very high, and the dust in the exhaust gas from waste incinerators contains a considerable amount of these alkaline components. When the denitration equipment no longer exhibits the expected performance, it is necessary to restore the catalyst performance. When dust mainly composed of earth metals accumulates inside the catalyst, its water solubility is used to thoroughly wash it with water. A method is provided.

Washing with water is the most effective method for regenerating a deteriorated catalyst due to the accumulation of poisonous substances, but it contains dust components and eluted catalyst components, and the amount of washing wastewater is several times the amount of catalyst. .

The problem is how to handle it.

The present invention relates to wastewater treatment that solves the above-mentioned problems.The present invention relates to wastewater treatment that solves the above-mentioned problems. It is characterized by a method for treating cleaning wastewater that is introduced into the flue of the furnace or into at least one of the gas treatment devices attached to the above-mentioned furnace, and is made non-drainage within the system, and its purpose is to discharge the cleaning waste liquid to the outside of the system. The point is that wastewater treatment is carried out within the plant system without any waste.

The present invention will now be described in detail with reference to the accompanying drawings. Figure 1 shows the case when applied to the exhaust gas denitrification equipment of a garbage incinerator.
This is an example.

During normal operation, garbage introduced from a hopper 1 is burned in an incinerator 2, and its exhaust gas passes through a flue 3 and is cooled by a gas cooling device 4.

After dust removal in the dust collector 6, the NOx in the exhaust gas and the ammonia gas 11 supplied as a reducing agent are reacted in the reaction zone 7vc in the denitrification catalyst layer, decomposing them into harmless nitrogen and water. The subsequent exhaust gas 8 is further passed into the wake. In the case of exhaust gas from a garbage incinerator, the concentration of fcHct produced by the combustion of vinyl chloride in the garbage is high. It is generally provided on the downstream side of the device (Figure 1 shows the case where it is provided on the upstream side).

If the performance of the catalyst deteriorates due to some reason during plant operation, such as accumulation of alkaline components in exhaust gas dust, cleaning water is introduced into the soot blowing device 13 from the outside.

The catalyst is washed with water through the entire cleaning nozzle 12 and regenerated.

Washing wastewater containing catalyst poisoning components and eluted active components 9
through the washing waste water outlet hopper 10.

It is introduced to each location within the plant system by a feed pump 14. These locations include an incinerator, a gas cooling device constituting a gas treatment device, a dehydrochlorination treatment tower, etc., and this introduction method may be carried out at three locations simultaneously or individually. The wastewater introduced into the incinerator evaporates immediately, and gas cooling equipment usually uses a cooling method that sprays water, and the wastewater is used as part of this cooling water, and this cooling water is recycled. Therefore, it is not discharged outside the system, making it possible to perform wastewater-free treatment. On the other hand, in dehydrochlorination treatment towers, a slurry solution of slaked lime or calcium carbonate is sprayed to replace HCl in the exhaust gas with chloride and remove it. can be processed. Even if washing wastewater is used, the function of deHC1 itself will not deteriorate in any way.

Can be processed effectively.

FIG. 2 shows an example of application to a boiler exhaust gas denitrification device, and is a simplified illustration of FIG. 1. In this case as well, the washing wastewater generated by the water washing regeneration is thrown into the boiler 15 and/or the flue 3, and is then disposed of therein. The other details are the same as those in FIG. 1, so the explanation will be omitted.

The washing water in this embodiment may also be an aqueous solution containing additive chemicals, and is not limited to water alone.

As explained above, the present invention enables the catalyst to be poisoned by alkaline dust in the exhaust gas, making it impossible for the denitrification equipment to perform at its initial level, and when the denitrification equipment is regenerated by water washing, without treating the washing waste liquid outside the system. It can easily be made waste-free within the system, and is very useful in practice.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment applied to a denitration device for exhaust gas of a garbage incinerator, and FIG. 2 is a flowchart showing an embodiment applied to a denitrification device for boiler exhaust gas. 2... Incinerator, 3... Flue, 4... Gas cooling device. 5...Dehydrochlorination treatment tower. (9)

Claims (1)

[Claims] The cleaning waste water generated when the exhaust gas treatment filler is washed and regenerated in the state of filling the reactor with water is collected in a boiler, a furnace such as an incinerator, the flue downstream of it, or at least one of the gas treatment equipment attached to the above-mentioned furnace. A method for treating cleaning wastewater, which is characterized by inputting it into a system and making it non-drainage within the system.