JPH0555186B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for regenerating a used catalyst used in the treatment of deodorizing malodorous gas using ozone in the presence of a catalyst.

<Prior art and its problems> It is known that the deodorizing method using ozone is based on the strong oxidizing ability of ozone. When this deodorizing method is carried out catalytically using a catalyst, its effectiveness is dramatically increased.
Manganese, iron, cobalt,
Examples include nickel, zinc, silver, platinum, palladium, and rhodium, but manganese is better in terms of performance and durability.

However, even with manganese catalysts, the catalytic activity decreases after long-term use. Therefore, there is a need for a method for regenerating a catalyst whose catalytic activity has deteriorated. Such a regeneration method involves washing with an ammonia aqueous solution, washing with water, drying, and then heating at 200 to 300°C.
A method of firing in an inert gas atmosphere is known (JP-A-58-219942). However, this method contaminates the working environment with ammonia, which has a strong odor, and requires many steps, so it cannot be called an easy method.

<Problems to be Solved by the Invention> An object of the present invention is to provide a simple and sufficient method for regenerating a spent catalyst containing manganese as the main active ingredient, which was used in a catalytic deodorization method using ozone. be.

<Means for solving the problem> As a result of intensive research in line with the above objectives, the present inventors have found that when using a catalyst containing manganese as the main active ingredient, it can be easily removed from the air without washing with aqueous ammonia or the like. Alternatively, the inventors discovered that catalytic activity could be sufficiently recovered by simply calcining in oxygen, and as a result of further studies, the present invention was completed. That is, the present invention
This is a catalyst regeneration method in which a spent catalyst containing manganese as the main active ingredient, which was used in a catalytic deodorization method using ozone, is calcined at 100 to 500°C in air or oxygen.

In the present invention, the catalyst is regenerated by firing in air or oxygen at 100 to 500°C, preferably 200 to 450°C. Possible causes of decreased catalyst activity in deodorizing methods using ozone include reaction products adhering to the catalyst and becoming poisonous substances, and ozone oxidizing the catalyst surface and producing manganese peroxide, which accumulates. It will be done. It is also thought that one of the causes is the adhesion of dust, moisture, and mist contained in the processing gas to the catalyst surface. 100 to 150℃ when the degree of catalyst activity deterioration is small, such as due to simple moisture adsorption.
It is sufficient to dry it to a certain degree, but in normal cases
It is best to bake at 200-500℃. Calcining at a temperature exceeding 500°C does not increase the catalyst regeneration effect and is disadvantageous in that the equipment becomes bulky and additional energy is required. Usually baking time 1-5
This is done using a firing furnace in about an hour.

By regenerating according to the method of the present invention, treatment with a chemical solution is not required, the process and equipment can be simplified, and the regeneration process can be performed easily.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited only to the Examples.

<Example> As an ozone decomposition catalyst, a catalyst consisting of a composite oxide of titanium-silicon and manganese dioxide and having a composition of 85:15 in weight ratio of each was used. Air containing 10 ppm of methyl sulfide and 20 ppm of ozone was passed through the catalyst at a space velocity of 50,000 hr ^-1 at room temperature,
The air was deodorized. After starting the process
When the methyl sulfide removal rate and ozone decomposition efficiency were measured after 4000 hours, they were 63% and 71%, respectively. The catalyst was taken out, placed in an electrically heated calcining furnace, heated, and calcined at 400°C for 3 hours to regenerate the catalyst.

The regenerated catalyst was used for ozone decomposition treatment under the same conditions as before. Immediately after the start of treatment, the methyl sulfide removal rate and ozone decomposition efficiency were 96% and 99%, respectively, indicating that the catalyst activity had been sufficiently recovered.

Claims (1)

[Claims] 1. A catalyst regeneration method characterized by calcining a spent catalyst containing manganese as a main active ingredient, which was used in a catalytic deodorization method using ozone, at 100 to 500°C in air or oxygen.