JPS614522A - Method for removing hydrogen sulfide contained in gas - Google Patents

Abstract

PURPOSE:To accelerate the regenerating reaction of an absorbing soln. in the inside of a regeneration tower, to diminish the consumed amount of air and to make an apparatus small-sized in the Takahax process by by oxidizing and regenerating the absorbing soln. with a bubble tower type regeneration tower provided with a rotary atomizer. CONSTITUTION:The gas contg. H2S is brought into contact with the absorbing soln. contg. 1,4-naphthoquinone-2-sulfonate catalyst in an absorption tower to absorb and remove H2S. Then, the absorbing soln. is fed to a regeneration tower. A rotary atomizer is provided to the lower part of the regeneration tower and air is fed from an air feeding port 3 of the inside of cup by rotating a cup- shaped rotator 2 at high velocity and dispersed into the soln. as fine bubbles. The regenerating reaction is allowed to proceed quickly by making the dispersion diameter of air fed by the rotary atomizer small and increasing the gas- liquid contacting area.

Description

[Detailed Description of the Invention] [Industrial Application Field] The method of the present invention relates to a method for removing hydrogen sulfide from gas,
In particular, it relates to improvements in the wet gas purification method using the Takahax method.

[Conventional technology]

Traditionally, quinones have been made water-soluble by introducing oxidizing groups.

The Takahax method is a wet gas purification method that uses an alkaline aqueous solution of hydroquinones or their metal salts to oxidize the remaining liquid in the gas to be purified to precipitate sulfur, then separate the sulfur and recirculate the absorbed liquid. It is known as
3-1284.

In the process used in this method, sodium 1,4-naphthoquinone-2-sulfonate is added as a catalyst, and an absorption liquid containing sodium hydroxide, sodium carbonate, sodium bicarbonate, etc. as an alkali source is added to an absorption tower. The liquid is brought into contact with a gas containing hydrogen sulfide flowing down from the top and introduced from the bottom of the tower 7, and after absorbing the contained hydrogen sulfide, the liquid is transferred to the bottom of a regeneration tower having a porous gas dispersion tube, etc. At the same time, compressed air is injected from the bottom of the column, and the action of the oxygen dissolved in the liquid and the catalyst in the absorption liquid oxidizes the absorbed hydrogen sulfide to precipitate sulfur, and the liquid is absorbed. This method regenerates it as a liquid and circulates it back to the absorption tower.

However, in the conventional method, a bubble column (having a dispersion plate or a dispersion tube) is usually used to regenerate the absorption liquid, which has the disadvantage that the residence time of the absorption liquid in the regeneration tower is long and the equipment becomes large. There was a problem that the amount of air used was large and the pressure loss of the distribution plate was large, resulting in an increase in power.

In view of the above circumstances, the present invention has been made to solve the above problems, and by adopting a rotary atomizer-type bubble column with high gas-liquid contact efficiency, an absorption liquid containing a large amount of hydrogen sulfide can be used. It used to promote oxidation regeneration, reduce liquid residence time, and reduce air usage.
The purpose of the present invention is to provide an improved oxidation regeneration technology that improves the hydrogen sulfide treatment capacity per circulating amount of absorption liquid, downsizes the device, and removes hydrogen sulfide-containing liquid with high efficiency.

[Means to solve problems]

d The present invention uses exhaust gas containing hydrogen sulfide,
1. After removing the hydrogen sulfide by bringing it into contact with an absorption liquid made of an alkaline aqueous solution containing a 4-naphthoquinone-2-sulfonate catalyst, the absorption liquid is transferred to a bubble column type regeneration tower having a rotary atomizer for oxidation and regeneration. The above object is achieved by a method for removing hydrogen sulfide from gas, which is characterized by the following.

[For production]

Hereinafter, one embodiment of the method of the present invention will be explained based on the drawings,
At the same time, reactions between each component will be explained in detail.

FIG. 1 is a system diagram of an embodiment of the present invention, in which hydrogen sulfide is contained in the gas to be purified, and the gas is introduced into the absorption tower 1 through a conduit 15, and the gas is introduced into the absorption tower 1 from the top of the tower. Liquid spray tube 15
The gas, which has been brought into countercurrent contact with the absorbing liquid sprayed from the pipe and from which hydrogen sulfide has been removed, is discharged from the conduit 14. In the absorption tower, hydrogen sulfide and, for example, sodium carbonate in the absorption liquid react as shown in equation (1) below to produce sodium hydrogen sulfide.

H! S + N al C03-chi N a HEI
+N a HCo, (1) The absorption liquid flowing out from the absorption tower 1 passes through the conduit 6 and is collected in the tank 5, but during this time, sodium 1,4-naphthoquinone-2-sulfonate and Na1S dissolved in the absorption liquid are reacts as shown in the following equation (2).

That is, the quinone type catalyst reacts with hydrogen sulfide, the hydrogen sulfide is mainly converted into sulfur, and the quinone type catalyst becomes a hydroquinone type catalyst.

The absorption liquid is then sprayed from the top spray pipe 16 of the regeneration tower 2 via the conduit 21 by the pump 7', brought into countercurrent or cocurrent contact with the air or oxygen-containing gas fed in from the compressor 19, and then Oxidative regeneration of the catalyst is carried out as shown in Eq.

OHO The absorbent thus sufficiently regenerated is collected in the tank 4 through the conduit 22 and circulated by the pump 7 to the absorption tower 1 via the conduit 1B.

Also, a part of the absorption liquid is press-fitted into the filter breath 12,
Precipitated sulfur suspended in the liquid is collected by filtration.

Here, the present invention uses a bubble column using a rotary atomizer with high gas-liquid contact efficiency in place of the conventional bubble column for oxidation regeneration of the absorption liquid with air or oxygen-containing gas.
Excellent in processing absorbent liquids.

Figure 2 shows a case in which a conventional bubble column is used to bring air into contact with an alkaline aqueous solution containing sodium t4-naphthoquinone-2-sulfonate that produces hydrosulfide, and a case in which a rotary atomizer according to the present invention is used. This is a graph showing a comparison of how the hydrogen sulfide ion concentration decreases over time when using a bubble column. In the 0 part of the figure, the hydrosulfide ions in the aqueous solution decrease in a short time, and in the 0 part they decrease with a gentle slope, so both follow almost the same trend, but it is clearly seen that there is a significant difference between the two. . In FIG. 2, 0 parts indicates that it is a diffusion-limited reaction that is related to the rate of supplying oxygen into the liquid film. Therefore, it can be seen that by adopting a regeneration method that increases the oxygen concentration and increases the contact efficiency between the absorption liquid and oxygen, it is possible to rapidly advance the regeneration reaction.

In order to efficiently advance the above-mentioned diffusion-limited reaction, the method of the present invention installs a rotary atomizer at the bottom of the reactor to reduce the dispersion diameter of the supplied air or oxygen-containing gas and to reduce the gas-liquid surface area. It is characterized by the adoption of a regeneration tower that increases contact efficiency.

FIG. 6 shows an example of a rotary atomizer used in the method of the present invention. In the figure, 1 is a liquid containing H and s, 2 is a cup-shaped rotating body (rotor), 3 is an air supply port, 4 is a shaft sealing device, and 5 is a driving device.

As shown in Fig. 3, the rotary atomizer produces -liquid 1 and a bulge-like shape. . Roll 4. Turn over -C0, and continuously feed air into the inside of the cup through the air supply port 3, causing the gas to overflow from the bottom end of the cup, and the overflowing gas is due to the difference in specific gravity between the gas and the liquid. A gas layer is formed on the surface of the rotating body 20 due to the centrifugal force effect. Since there is a relative velocity between this gas layer and the liquid around the rotating body, the gas layer is torn off by the friction between them, forming fine bubbles and dispersing them in the liquid.

A drive device 5 is required to rotate the rotating body 2 at high speed, but because the rotating body has no protrusions and the atmosphere around the rotating body is close to gas, its power consumption is comparable to that of a normal stirring blade. It has the advantage of being very small compared to .

In addition, the fluid that comes into contact with the shaft seal 4 is only gas, and even if the liquid contains solid matter such as sulfur particles, the liquid does not come into contact with the shaft seal 4. There is no fear of damage, it is a perforated plate.

Since there are no pores like in a porous dispersion cylinder, problems such as clogging of holes can be completely avoided.

← Reduce the bubble diameter of the rotary atomizer and
1i Due to the effect of increasing the liquid contact area, H in the unit liquid,
It has become possible to significantly reduce the amount of air required per s amount.

FIG. 4 is a graph comparing the reaction rate of a regeneration tower using a conventional type dispersion plate or dispersion cylinder for bubble dispersion and the reaction rate when using the rotary atomizer of the present invention.

The horizontal axis of the graph in Fig. 4 shows the superficial velocity, and the vertical axis shows the reaction rate ratio. The absolute value of the first-order reaction rate constant in units of /h) is expressed as a ratio to the lower limit of the reaction rate of a rotary atomizer with a superficial velocity of 2.9 twy' days as 100.

The shaded area shows the operating conditions, such as the concentration of hydrogen sulfide ions in the feed liquid, the air utilization rate, and the concentration of hydrogen sulfide ions in the treated liquid.

It shows the range of the reaction rate ratio that varies depending on the catalyst concentration, the stirring conditions of the rotary atomizer, etc. That is, it can be seen from FIG. 4 that the superficial velocity to obtain the same reaction rate is, for example, 2.9 cm/.theta. in the conventional method, whereas in the present invention, it may be about 15 cm/.theta. However, the higher the reaction rate is required, the more this ratio tends to approach 100%. Therefore, in the present invention, the superficial velocity is taken into consideration so as not to exceed the superficial velocity of the conventional dispersion plate. Preferably, the range is from 0.5σ/θ to U-1.

Although the optimum value of the superficial velocity varies slightly, it is within the necessary and sufficient operating range for treating hydrogen sulfide-containing liquids.

Furthermore, in the regeneration tower equipped with the rotary atomizer of the present invention, in addition to being able to reduce the superficial velocity, that is, the amount of air, the regeneration reaction of the absorption liquid takes place quickly in the regeneration tower, so the volume of the regeneration tower can be reduced. It is possible to reduce the size of the device.

〔Example〕

Actual liquid (Takahax liquid; Na1O031-5X, NaHCOa 1-5
%.

Na2820210~30 X HNaps 1~10
mot/nl + catalyst 1~1 o mat/rl
) was inserted. While blowing a predetermined amount of air shown in Table 1 below through the air inlet of the rotary atomizer, sample the liquid at fixed time intervals (0, 5, and 10 minutes) to determine the concentration of hydrosulfide ions in the Takahax liquid ( H8-) was actually measured. Each condition and test result is summarized in Table 1.

Table 1 [Effects of the invention] It is clear from the detailed explanation above and the examples that 4
In other words, the method of the present invention uses a rotary atomizer type bubble column with high gas-liquid contact effect, which reduces the amount of air, speeds up the absorption liquid regeneration reaction in the regeneration column, and improves the hydrogen sulfide treatment capacity. Since the equipment can be made smaller and the hydrogen sulfide removed efficiently. Furthermore, the use of a rotary atomizer has the great advantage of not only significantly reducing power consumption, but also eliminating problems such as clogging, which occur with conventional perforated plates and porous dispersion tubes.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing the concentration of hydrosulfide ions (rrtnot/l
), Figure 5 is an explanatory diagram of the rotary atomizer attached to the lower part of the regenerator, and Figure 4 is a graph showing the conventional bubble column (using 9 dispersion plates) and the rotary atomizer of the present invention. FIG. 2 is a diagram showing a comparison of reaction rates of bubble columns. Sub-Agent 1) Akira T・1 Sub-Agent Ryo Hagiwara - Figure 3 Figure 4

Claims (1)

[Claims] Exhaust gas containing hydrogen sulfide is treated with 1,4-naphthoquinone-2-
A method for removing hydrogen sulfide by contacting an absorption liquid made of an alkaline aqueous solution containing a sulfonate catalyst, and then oxidizing and regenerating the absorption liquid using a bubble column type regeneration tower having a rotary atomizer. Hydrogen sulfide removal method.