JPS5949849A - Regenerating method of poisoned denitration catalyst by rinsing - Google Patents

Abstract

PURPOSE:To activate and regenerate quickly a large amt. of poisoned catalysts in a short time by immersing the poisoned catalysts removed from the fixed bed of a catalytic reaction device by each unit of said catalyst into a tapping water tank and rinsing the catalysts. CONSTITUTION:The denitration catalysts of honeycomb bodies or the like consists of the catalysts produced by coating catalytically active components consisting of >=1 kinds among metallic oxides of Ti, V, W, etc. on the surface of a catalyst carrier consisting of alumina, mullite, etc. or catalyst produced by molding the mixture thereof is regenerated and activated by the following method. If the above-described denitration catalyst installed in the fixed bed of a catalytic reaction device are used for a long-time denitration treatment and have deteriorated catalytic activity owing to sticking of dust, etc., such poisoned catalyst is removed by each unit body from the fixed bed. The dust is removed from the catalyst preferably by compressed air or vacuum suction for every unit. The units are then immersed in a rising tank and water is run through the through-holes of the catalyst to rinse and remove the dust-components. Such units are immersed in the 2nd tapping water tank and the poisoning components such as alkali metal deposited or impregnated on or in the catalysts are dissolved out and the catalyst is thus activated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides: (1) When the denitrification catalyst packed in a fixed-time catalytic reaction apparatus has a low catalytic activity due to long-term use, the catalytic activity of the poisoned catalyst can be quickly reactivated and regenerated. This paper relates to a water washing regeneration method for poisoned denitrification catalysts.

Fixed-bed dry exhaust fan denitrification systems using honeycomb-shaped or lattice-shaped catalysts have been gaining popularity in recent years because they have a spacer structure, are less likely to be clogged by dust, and can achieve high denitrification rates. The waste field in the combustion exhaust gas discharged from many Confucian furnaces such as large power boilers and various leaf boilers!
It is used as a white 614 device.

Among them, the denitrification equipment section used for the Ichiichi Rikigawa large-scale boiler, etc., which removes especially large amounts of exhaust gas, is reassuringly equipped with a catalyst bed of several white I11, and in order to make it easier to handle, the denitrification equipment section is By storing the a medium in a frame to form a unit body, and thereby eliminating the single-stream element,
It has become especially popular recently.

However, such a dry process 1;
Due to long-term use, the dust contained in the exhaust gas decreases by 1.
Then, the alkali gold contained in the tasto combines with the poisoning component or catalyst component of 3K 4p, and
The IR medium activity may decrease and the safe operation of boilers, etc. may be compromised. The low level of oiliness of this denitrification catalyst is due to chemical reaction bonds, so methods such as simply blowing off the adhering dust on the surface of the catalyst with a compressed Tsumugi Tsurunkiji will not fully restore the activity. It is something that cannot be obtained.Therefore,
When it was discovered that the activity decreased due to poisoning, measures were taken to replace the catalyst with a new one, but since denitrification catalysts are extremely expensive, it is not possible to replace them with new ones every few years. 1il (There are major problems such as increased private expenses and disposal of deteriorated catalysts.

For this reason, various methods for regenerating poisoned denitrification catalysts have recently been studied and many proposals have been made. Among them, it has been proposed to wash the poisoned Hypothesis 61i catalyst in an aqueous solution of H, So, HOl, or the like.

However, as mentioned above, in the denitration (+11) system used in large power boilers of several g mB, the denitrification catalyst, which is normally housed in a unit, is disassembled into a single catalyst body. It takes an extremely large amount of man-hours and labor costs to perform the water-washing reactivation treatment, then repack the unit into a unit, and install it on a fixed bed. It is practically impossible to carry out such water washing regeneration treatment, and as a result, it is necessary to have a spare catalyst, which has been an important point for many years in practical use.

The present invention solves these drawbacks and problems of the conventional methods, enables rapid and short-term handling of large batches, and a poisoning theory (inspired by the water-washing regeneration method for iF4 catalysts) that enables activation and regeneration of catalysts. This is a water washing regeneration method for class 'JL denitrification catalysts, in which the poisoned catalyst units removed from the fixed bed of the catalyst reactor are placed in a running water tank and each poisoned catalyst unit is washed with water. .

The structure of the present invention will not be explained in more detail.
i, V, W, No, Or, Ni
, Fe.

Zr, Mn, Sn, Zn, Tju, Co
'! The catalyst shape is honeycomb-like, lattice-like, pipe-like, plate-like, preferably honeycomb-like. A denitrification catalyst consisting of various shapes is housed in a frame and formed into a unit body of about 1 to 8 m in length, and a large number of such unit bodies are stacked on a fixed bed of a catalyst anti-shallow equipment for long periods of time at IMJ. When 1ift nitrile treatment is used and the catalyst activity decreases due to adhesion of dust, etc., the poisoned catalyst is removed from the fixed bed in each unit and preferably compressed air or vacuum suction is applied to each unit. Remove adhering dust. Thereafter, the unit body is washed with water or preferably immersed in a first water washing tank, and water is made to flow through the through holes of the catalyst to wash off the dust. In this case, the washing time in the first water tank may be about 80 seconds to 30 minutes.

After removing the dust in this manner, remove water droplets adhering to the catalyst with air blow or clean water, and place the unit into a second running water tank. The catalyst is soaked in water to remove poisonous components such as alkali gold M attached to the catalyst. In this case, the flow direction of the water and the flow direction of the waste in the unit body are made to be parallel to each other, and for example, in the case of a honeycomb-shaped catalyst, water is caused to flow through the through holes. Also, the flow rate of the flowing water is 0-0
11117s or more is fine, but preferably o, os
m/ or more, the effect of elution of poisonous substances on the catalyst surface is excellent, and the regeneration effect is also crystallized.

Further, the water washing time is 30 minutes to 120 minutes, and the time between water washings 111 is changed depending on the degree of deterioration of the catalyst to be washed.

Furthermore, the water used for washing is 100% H, So.

He/ , ) L, O, etc. may be included, but as a poisoning component, alkali metal ions such as Na are added to U, 5
Must not contain more than Vt. And after washing with water J+Z
Use air or hot air to remove any buildup and dry it.

Next, the effect of the present invention will be explained based on an example of 4%.

M5 a) Touch gt1 (on the body:, Ti02-V2o5-
The cross-sectional shape of the through-hole in a single catalyst body made of a honeycomb-shaped catalyst supporting an active substance made of Wo8 is square, and the size of the through-hole is 5#I@ and the outer 11 dimensions are l 5 Q
＃＋l A poisoned catalyst with low catalytic activity was prepared after being used for one year.

After removing dust from each unit of this poisoned copper removal catalyst using a vacuum cleaner, the ratio of catalyst capacity to water washing and water sprinkling is 1.
= 4 il water tank for 10 minutes to remove adhering dust, and then put each unit into a second tank,
Water washing was performed for 60 minutes under the conditions of water washing, water quality, and flow rate listed in Table 1. For comparison, the unit body was disassembled and each single catalyst body was washed with water in the same manner.

The denitrification properties of these water-washed catalysts were comparatively measured by flowing exhaust gas at 880°C in the presence of ammonia. The gas composition at the time of measurement was NOx i, 20
ppm z NHB 120'ppm, 02
4 vo1%, 00211 vo1%, H2O10VO
I%, the balance was N2. The results are shown in Table 1.

The time required for this regeneration process (total time per person) is also compared and listed in Table 1.

As is clear from the results in Table 1, according to the method of the present invention, the time required to regenerate the poisoned catalyst is less than half of the conventional method, and the regeneration process can be easily performed to a high denitrification rate quickly and inexpensively. .

As described above, according to the present invention, it is possible to regenerate a poisoned catalyst without dismantling the catalyst unit installed in a fixed bed type catalytic reaction device, and in particular, it is possible to regenerate a poisoned catalyst without dismantling the catalyst unit installed in a fixed bed type catalytic reaction device. Denitration 71J11! It is possible to activate and regenerate a large quantity of poisoned catalysts, such as those used in medium equipment, which can be as large as hundreds of m8, in a very short time and at low cost, and is a useful method for regenerating denitrification catalysts in the production canal.

Patent applicant: Nippon Insulator Co., Ltd. Same applicant: Mitsubishi Heavy Industries, Ltd. 280-

Claims (1)

[Claims] L. Poisoning characterized by immersing the poisoned catalyst unit removed from the fixed bed of the catalyst anti-Jii5 device in a running water tank and washing each poisoned catalyst unit with water. Water washing regeneration method for denitrification catalyst. & The poisoned denitrification catalyst according to claim '4R'L M11, paragraph 1, wherein the poisoned catalyst is a honeycomb catalyst having a honeycomb structure, and water is washed by flowing water into the through holes of the honeycomb catalyst. Water washing regeneration method.