JPS59129320A - Method for blowing soot - Google Patents

Abstract

PURPOSE:To efficiently clean a catalyst in a gas treating unit by a simple way, by intermittently blowing off high pressure gas to solid matter adhered and deposited on the surface of a catalyst. CONSTITUTION:When a catalyst, having a gas permeable hole part and being built in a gas treating unit, is cleaned, high pressure gas is blown off to the catalyst from a soot blow nozzle which is installed opposed to the gas permeable hole part of a catalyst, intermittently within a specified time; 3sec at the interval of 3sec, for example. By forcibly causing turbulence in gas, the deposited solid matter can be removed from the catalyst efficiently. By this method, the injected rate of air and steam can be decreased respectively, in comparison with the conventional continuous method of injection, and the solid matter can be removed without giving any bad effect to the catalyst while this operation is taken place, as the temperature on the surface of a catalyst is scarecely lowered.

Description

[Detailed description of the invention] The present invention relates to a heavy oil boiler, a coal-fired boiler, and an internal combustion engine.

Smoke and dust produced by gas turbines, garbage incinerators, etc.

Relating to a soot blowing method in which solid matter adhering to the catalyst surface of a catalyst layer for denitration, etc. is removed by injection of high-pressure gas in a treatment device for exhaust gas containing solid matter (hereinafter referred to as solid matter). .

Conventionally, the soot blowing method is widely known as one of the means for removing 411 solid matter. However, in the conventional soot blowing method, gas injection is performed at the point when the pressure drop in the catalyst layer starts to rise, or 1 to 93 times/
Gas injection is performed continuously for a certain period of time (5 to 10 minutes) per day. When gas injection is carried out continuously, albeit for a short period of time, the amount of solid matter removed becomes considerable, and the removed solid matter is temporarily released from the tank into the atmosphere. Therefore, there is a risk of secondary pollution.

In addition, when air or the like is used as the high-pressure gas required for injection, if the injection is performed continuously, albeit for a short period of time (5 to 10 minutes), the catalyst surface temperature will drop over time.
There is a risk of catalyst deterioration.

Therefore, recently, heated air, heated steam, etc. are used as the injection gas. In this method, the surface temperature of the catalyst does not drop to the bottom, so it may cause its deterioration.However, this method requires complicated equipment, which causes phlegm build-up.

The present invention attempts to solve these problems, and aims to provide a soot blowing method that enables efficient cleaning of catalysts in power input processing equipment using simple means. purpose.

For this reason, the soot blowing method of the present invention is such that when cleaning the catalyst in a gas processing apparatus incorporating a catalyst having a gas passage hole, from a soot blow nozzle installed opposite to the gas passage hole of the catalyst, Crucible attached to the catalyst surface:
The method is characterized in that the accumulated solids are removed by intermittently injecting high pressure gas onto the solids.

Normal soot blow nozzles include straight nozzles,
Generally, a Venturi type A.5 sl calculation is used, and the injection pressure of the gas cylinder is 5 kg/cm2G + the injection speed at the collision surface (catalyst part) is about 20 to 40 m/s.

In the conventional soot blowing method, gas is continuously injected under certain conditions within a certain period of time, whereas in the suld blowing method of the present invention, gas is injected intermittently within a certain period of time, for example, at 3 second intervals for 3 seconds. In this way, high-pressure gas is injected to forcibly cause gas turbulence while removing attached solid matter.

That is, one condition in which deposits are easily removed is when turbulence occurs in the gas, or in other words, when a temporary shock is applied, the deposits are easily removed. Note that the state of adhesion of solids differs depending on the nature of the exhaust gas, but for example, in the case of exhaust gas from burning asphalt, the state of adhesion of solids is in the form of cracks, and in this case, intermittent injection of high-pressure gas is particularly effective. It is.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In a gas treatment device, a catalyst having a gas passage hole is
The catalyst is exposed to heavy oil-fired exhaust gas for 15,200 hours, thereby causing solid matter to adhere to the catalyst. In this state, continuous injection and intermittent injection of high-pressure gas are performed using a soot blow nozzle installed opposite to the gas passage hole of the catalyst. Table 1 shows the test results after removing solid matter. The test conditions for both injections were an injection pressure of 5 kg/cm2G, a venturi nozzle with an inner diameter of 6 mm, room temperature air as the injection gas, and a collision speed of 30 m/s on the catalyst surface. In the case of intermittent injection, the injection was performed XIO times for 10 seconds at 1-minute intervals, and in the case of continuous injection, the injection was performed continuously for 1 () minutes, and the two were compared.

Table 1 As a result, as shown in Table 1, there was no significant difference in the solid matter removal effect between the two, and the removal rate of both was about 95%, which was a good result.The degree of decrease in catalyst surface temperature was
In the case of continuous injection, the temperature dropped from 380°C to 36 (approximately 1'C), whereas in the case of intermittent injection, the temperature dropped to 2-3
°C, which was only a slight drop.

Table 2 shows the test results for comparing the two when only the injection time was changed in the same way. In this test, continuous injection was performed for 5 minutes in the case of continuous injection, and 1 minute in the case of intermittent injection.
The conditions were set to 5 sand injections x 10 times at minute intervals.

Table 2 As a result, the solid matter removal effect decreased slightly to 90% in the case of continuous injection and 85% in the case of intermittent injection.
Regarding the degree of catalyst surface temperature drop, in the case of continuous injection, 3
The temperature increased from 80°C to 365°C, whereas in the case of intermittent injection, a good result of about 1°C was obtained.

As detailed above, according to the soot blowing method of the present invention, various intermittent injection conditions are combined depending on the exhaust gas conditions to temporarily cause gas turbulence while removing solids attached to the catalyst. Compared to conventional continuous injection methods, the amount of air, steam, etc. injected is reduced, and the drop in catalyst surface temperature is extremely small. It has the advantage of being able to remove solids.

Claims (1)

[Claims] When cleaning the catalyst in a gas treatment device containing a built-in catalyst having gas passage holes, solids deposited on the surface of the catalyst are removed from the soot plow nozzle installed opposite to the gas passage holes of the catalyst. A soot blowing method, characterized in that solid matter is removed by intermittently injecting high-pressure gas onto the material.