JPS6034743A - Regeneration of used denitration catalyst - Google Patents

Abstract

PURPOSE:To obtain regenerated denitration catalyst having high performance by a simple process wherein used denitration catalyst is washed in a solution contg. component having catalytic activity. CONSTITUTION:Used denitration catalyst is washed with a soln. contg. components having catalytic activity instead of washing with water. Such components having catalytic activity are compd. contg. at least one among V, Fe, Ni, Mo, Co, Cu, Cr, Sn, W, U. These compds. are usually available in the form of oxides, however, it is preferred to use solution of these metallic compds. in water or in mineral acid such as H2SO4. By the washing in accordance with this invention, satisfactory regeneration effect of catalytic activity is recognized in regenerated catalyst, and same degree of catalytic performance as high as fresh catalyst is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating a used denitrification catalyst, and more particularly to a simple method for regenerating a spent catalyst used in a flue gas denitrification device using ammonia catalytic reduction.

Conventionally, N has been used to remove nitrogen oxides (NOx) contained in exhaust gas, particularly from boilers.

A known method is to add ammonia to exhaust gas containing X and bring it into contact with a metal oxide catalyst to catalytically reduce NOx contained in the exhaust gas, reducing it to nitrogen that is harmless to the human body. The metal oxide catalyst body used in this method consists of, for example, an active metal oxide catalyst adhered to a carrier formed into a cylinder, honeycomb, plate, or the like.

Conventionally, a method of washing with water was proposed as a simple reprocessing method after using such a catalyst body.
This method has problems such as incomplete recovery of activity and, depending on the properties of the exhaust gas during use, almost no recovery of activity may be observed.

An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a method for obtaining a high-performance regenerated denitrification catalyst through simple processing.

In short, in the present invention, instead of washing a used denitrification catalyst with water, it is washed with a solution containing active ingredients such as vanadium and iron.

In the present invention, the catalytically active components include vanadium,
Examples include compounds containing one or more of iron, nickel, molybdenum, cobalt, copper, chromium, tungsten, tin, and uranium. These compounds are generally obtained in the form of oxides, but in the cleaning of the present invention, solutions in which these metal compounds are dissolved in water (including hot water) or mineral acids such as sulfuric acid are preferably used.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Examples 1 to 12 A used plate-shaped catalyst body that was used for exhaust gas denitration of Ichiura-fired boiler exhaust gas and had lost its required performance was cleaned under the conditions shown in Table 1, and then placed in a constant temperature dryer. and dried at 180° C. for 2 hours. In order to confirm the regeneration effect, Table 1 shows a comparative example in which cleaning was performed with only water. The catalytic activity of the regenerated catalyst thus obtained was measured under the conditions shown below.

Catalytic activity measurement conditions AV: 15m/h.

Temperature: 350°C Gas composition: NOx = 200ppm, SO2 = 500ppm
m, 02 = 3%, CO2- 12%, H20 = 12%, N2 = remainder (NH3)/(NOX): 1.2 The results are shown in Table 2, and compared with the conventional technology shown in the comparative example. However, it was found that the regenerated catalyst according to this example had a good regeneration effect, and the same performance as a new catalyst could be obtained.

The following is a blank space: Table 1: Ratio of Asa n Lucidity to Responsibility Table 2: Examples 13 to 17 The same used plate-shaped catalyst body as that used in Examples 1 to 12 was After washing under the conditions shown in the table, it was dried in a constant temperature dryer at 180"C for 2 hours.The denitrification performance of the regenerated catalyst thus obtained was measured by the method described above. The results shown in the table were obtained, and it was confirmed that the performance of the regenerated catalyst according to this example was equivalent to that of a new catalyst.

Table 4 Example 18 The same used plate catalyst as used in Examples 1 to 12 was heated at 15°C, 149g VO, which is 10 times the catalyst capacity.
After washing with a solution of 3O4/11 HzO by spraying, it was dried at 180°C for 2 hours. The performance of the thus obtained regenerated catalyst was measured under the conditions described above and was found to be 97%, which was equivalent to a new catalyst.

As described above, according to the present invention, the incompleteness of activity recovery, which was a problem with conventional regeneration techniques, is removed and reduced, and a regenerated catalyst having the same performance as a new catalyst can be obtained by a simple method. .

Agent: Patent Attorney Kawakita Takecho

Claims (1)

[Scope of Claims] (1) A method for regenerating a used denitrification catalyst, which comprises washing the used denitrification catalyst in a solution of a catalytically active component. (2. Claim 1, characterized in that the catalytic active component is a compound of one or more of vanadium, iron, nickel, molybdenum, cobalt, copper, chromium, tungsten, tin, and uranium. (3) The used denitrification catalyst according to claim 1, characterized in that the spent catalyst is washed one or more times with water or an acid solution before treatment. Media playback processing methods.