JPH11276841A - Device for submerged regeneration in wet desulfurizing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for submerged regeneration in wet desulfurizing equipment, which has high air use efficiency, can be easily installed and maintained, and is inexpensive in the equipment and operation costs, and to provide a simple method for installing the device for the submerged regeneration without stopping the operation of the desulfurizing equipment. SOLUTION: This device for submerged regeneration in wet desulfurizing is formed by installing a plurality of perforated nozzles for injecting an oxygen-containing gas on the bottom side wall of a regeneration tower 6 in wet desulfurizing equipment in which a hydrogen sulfide-containing gas is brought into contact with a redox system catalyst-containing absorption liquid in an absorption tower 2 to absorb and remove the hydrogen sulfide, this hydrogen sulfide-containing absorption liquid is brought into contact with the oxygen-containing gas in the regeneration tower 6 to be oxidized and liberate sulfur to regenerate the redox system catalyst, and the regenerated absorption liquid circulates to the absorption tower 2. In this method for installing the device for submerged regeneration, after punching a plurality of installation holes onto the bottom side wall of the regeneration tower 6 by an incessant hole drilling method, the perforated nozzles for injecting the oxygen-containing gas, connected to valves adjusting the injection amount of the oxygen-containing gas, are attached to these installation holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for absorbing and removing acidic impurities such as hydrogen sulfide and hydrogen cyanide contained in a fuel gas such as a coke oven gas by contact with an absorbing solution.
The present invention relates to an in-liquid regenerator for wet desulfurization in which an oxygen-containing gas is blown into the absorbent to oxidize and regenerate the absorbent, particularly to an existing wet desulfurization facility equipped with an air regenerator with low air utilization efficiency. It is suitable for remodeling to a submerged regenerating device with high density.

[0002]

2. Description of the Related Art Coke oven gas, petroleum cracked gas, natural gas, and various industrial waste gases contain hydrogen sulfide and the like, and if these are used as fuel gas as they are, sulfur oxides are generated during combustion to produce atmospheric air. If it is used as a raw material gas as it is, the reaction equipment and the like are corroded, the catalyst is deteriorated, and the product is contaminated. Accordingly, hydrogen sulfide-containing gas such as coke oven gas is used for various purposes after desulfurization. As a conventional desulfurization technique, in addition to a dry desulfurization method in which hydrogen sulfide is reacted with metallic iron and fixed, a wet desulfurization method using a so-called redox catalyst is known. This wet desulfurization method is suitable for desulfurizing a large amount of gas, and typical wet desulfurization methods include the Fumax method using picric acid, the Stredford method using anthraquinone sulfonate, and naphthoquinone sulfonate. The Takahax method to be used is exemplified. In each of these methods, a hydrogen sulfide-containing gas is brought into contact with an alkaline solution containing a redox catalyst to absorb and separate hydrogen sulfide, and the absorbing solution that has absorbed hydrogen sulfide is regenerated with an oxygen-containing gas, and the regenerated solution is again used. This is a method in which hydrogen sulfide is recovered as sulfur or a sulfur compound by circulating it as an absorbing solution.

The desulfurization reaction mechanism is as follows when desulfurizing a coke oven gas by the Humax method, for example. First, in the absorption tower, coke oven gas includes ammonia (NH ₃ ), hydrogen sulfide (H ₂ S) and hydrogen cyanide.
(HCN) is absorbed in the absorbing solution as ammonium bisulfide (NH ₄ HS) and ammonium cyanide (NH ₄ CN), and the ammonium bisulfide is oxidized by picric acid in the absorbing solution to separate sulfur (S). This sulfur is consumed as a sulfur source of ammonium polysulfide ((NH ₄ ) ₂ S _{X + 1} ) generated in the absorption tower and reacts with ammonium cyanide to form ammonium rhodate (NH ₄ SCN). At this time, the NO ₂ group of picric acid is reduced to NHO
When the amount of picric acid relative to hydrogen sulfide is small, the NHOH group is further reduced to an NH ₂ group.

On the other hand, in the regeneration tower, ammonium hydrosulfide in the absorbing solution is oxidized by the oxygen-containing gas to form ammonium thiocyanate, and picric acid in a reduced state is oxidized by the oxygen-containing gas in the regeneration tower to recover the original acid. Regenerated into picric acid. The reaction of picric acid in wet desulfurization is as follows.

Embedded image

[0005] The amount of oxygen consumed in the regeneration step needs to be about 0.7 mole times the amount of hydrogen sulfide to be treated. For example, in a desulfurization facility with a coke oven gas treatment capacity of 100,000 Nm ³ / hr, the amount of air About 10,000 Nm ³ / hr (in the case of an air use efficiency of 10%). Therefore, the absorbent regenerating device of such a desulfurization facility has a height of 25 m and a diameter of 1 m.
It consists of a huge regeneration tower of 0 m, a huge air blower, an absorption liquid circulating pump, etc., and in addition to huge equipment and power costs, is a facility that treats corrosive gases and liquids, so a large amount of maintenance costs Need.

In a conventional desulfurization facility, a so-called air regeneration (gas phase oxidation) system is adopted in which the regeneration air is charged from the lower part of the regeneration tower, and the absorbent is dropped from the upper part of the tower and brought into countercurrent contact. There were many things. However, this air regeneration system does not have a high liquid dispersion efficiency and a short gas-liquid contact time, so that the air use efficiency is as low as 5 to 10%, requires a huge regeneration device, and requires a large power cost. I had to become something. In the in-liquid regeneration (liquid-phase oxidation) method such as the Takahax method, a premix method in which a gas to be treated and an absorbing solution are preliminarily mixed and charged into a regeneration tower (Japanese Patent Publication No. 58-4)
No. 9,590) and a horizontal gas-liquid mixing method (Japanese Patent Laid-Open No.
2-192,490) and the like.
This submerged regeneration system can be a relatively compact facility, but changing the equipment constructed by the aerial regeneration system to the submerged regeneration system requires significant remodeling of the tower itself, It is necessary to make the discharge pressure of the pump and the blower considerably high, which is almost impossible in terms of economy.

Further, Japanese Patent Application Laid-Open No. 3-42,011 discloses that an absorption tower and a regeneration tower are spontaneously connected at a lower portion thereof, and a regenerated absorbent from the regeneration tower is circulated to the absorption tower via a deaeration tank. A submerged regeneration method has been proposed. In this method, an expensive gas-liquid mixing nozzle described in JP-A-62-192490 is used for blowing the regeneration air, so that the equipment cost increases, and the apparatus of the air regeneration method is modified to this method. In order to achieve this, the desulfurization facility must be shut down for several months, so that there is a problem that it cannot be used in a situation where the operating rate of the coke oven is high.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wet desulfurization facility having a high air utilization efficiency,
An object of the present invention is to provide a submerged regenerating apparatus that can be easily installed and maintained, and has low equipment costs and operating costs. Another object of the present invention is to provide a simple mounting method of such a submerged regenerating apparatus without stopping the operation of a desulfurization facility.

[0009]

That is, the present invention relates to a hydrogen sulfide-containing gas which is brought into contact with a redox catalyst-containing absorbing solution in an absorption tower to absorb and remove hydrogen sulfide, and the hydrogen sulfide-containing absorbing solution is recovered in a regeneration tower. In wet desulfurization in which sulfur is released by contact oxidation with an oxygen-containing gas to release sulfur and regenerate the redox catalyst, and the regenerated absorbent is circulated to the absorption tower, a porous type for jetting the oxygen-containing gas is provided on the bottom side wall of the regeneration tower. This is a submerged regeneration device in wet desulfurization in which a plurality of nozzles are installed.

The present invention also relates to a hydrogen sulfide-containing gas which is brought into contact with a redox catalyst-containing absorbing solution in an absorption tower to absorb and remove hydrogen sulfide, and the hydrogen sulfide-containing absorbing solution is oxidized with an oxygen-containing gas in a regeneration tower. In order to liberate sulfur and regenerate the redox catalyst, and in the wet desulfurization in which the regenerated absorbent is circulated to the absorption tower, a plurality of mounting holes are pierced in the bottom side wall of the regeneration tower by a continuous perforation method. A method for mounting a submerged regenerating apparatus in wet desulfurization, comprising: installing, in each of a plurality of mounting holes, a porous nozzle for discharging an oxygen-containing gas connected to a valve that adjusts a discharge amount of an oxygen-containing gas. .

Hereinafter, the present invention will be described in detail. In the submerged liquid regeneration apparatus of the present invention, a porous nozzle having a simple structure and a low production cost is used as a nozzle for ejecting the oxygen-containing gas of the regeneration tower in place of a conventional gas-liquid mixing nozzle having a complicated and high production cost. It is used. This multi-hole nozzle has a structure in which a large number of through holes are provided on the front surface of the nozzle, and the through holes communicate with the air chamber. The air chamber is connected to an oxygen-containing gas pipe such as air. It is preferable that these through holes are regularly arranged on the center of the nozzle and on the concentric circumference thereof. Further, in order to efficiently disperse the oxygen-containing gas in the liquid, it is preferable that the center of the nozzle protrudes from the peripheral edge rather than the flat front face of the nozzle. The nozzle hole diameter and the number of holes may be determined as appropriate according to the liquid depth of the regeneration tower and the discharge pressure of the oxygen-containing gas in consideration of the utilization efficiency of the oxygen-containing gas.

The porous nozzle used in the present invention is not particularly limited as long as it has the above-mentioned structure, but as shown in FIG. 5, the porous nozzle 35, the storage box 36, the steady rest 37, the stuff-in nozzle It is preferable to install the nozzle set 34 including the box 38, the ejection amount adjustment valve 39, the gland packing 40, and the like. In addition, if a cleaning steam pipe (not shown) is connected between the multi-hole nozzle 35 and the ejection amount adjusting valve 39, steam cleaning of the nozzle can be performed at any time without stopping the regenerating device. .

Further, in the submerged regenerating apparatus of the present invention, a plurality of perforated nozzles are installed according to the capacity of the desulfurization facility. In order to increase the gas-liquid contact efficiency, the installation location should be regularly installed on the side wall of the tower as close to the bottom as possible. The plurality of nozzles may be installed so that the distance from the tower side wall is constant, but it is preferable to alternately install short nozzles and long nozzles in order to uniformly disperse bubbles in the liquid.

Although the submerged regeneration apparatus of the present invention may be installed in a newly installed wet desulfurization facility, it is particularly suitable for converting an existing air regeneration type desulfurization facility to a submerged regeneration system. If necessary, the submerged regeneration apparatus of the present invention can be additionally installed in addition to the existing air regeneration system. In this case, since the regeneration capacity of the absorbing solution is increased, it is effective to enhance the processing capacity of the existing wet desulfurization equipment.

In order to convert an existing air regeneration type desulfurization system to a submerged regeneration system or to additionally install a submerged regeneration device,
Usually, the operation of the desulfurization facility will be stopped during the construction period of several months. Therefore, the coke must be prepared and stored in advance, the operation rate of the coke oven must be reduced, and during this time the remodeling work has to be carried out in accordance with the coke production plan.

In the present invention, by adopting the improved continuous nozzle insertion method, the remodeling work of the equipment can be performed safely and reliably without stopping the operation of the desulfurization equipment. First, a plurality of mounting holes are drilled on the side wall of the regeneration tower by a continuous drilling method, and a porous nozzle for jetting the oxygen-containing gas is installed in each of these mounting holes. Connect the adjustment valve. After the adjustment valve is closed and attached to the valve for continuous perforation, the valve for continuous perforation is opened and the spray nozzle of the porous nozzle is inserted into the tower. Finally, by connecting the oxygen-containing gas pipe to the regulating valve,
Installation work is completed. During this time, the existing aerial regeneration device may be operated, the regeneration operation of the absorbent is continued, and there is no need to stop the desulfurization equipment. The submerged regenerating apparatus thus installed can start operation by opening the ejection amount adjusting valve and sending oxygen-containing gas (air) to the porous nozzle. The improved continuous nozzle insertion method can be widely applied to not only the remodeling work of the regeneration tower but also the remodeling work of the absorption tower, as well as the remodeling and renovation work of various chemical plants.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing the concept of a wet desulfurization facility, FIGS. 2 and 3 are side sectional views and an elevation view showing an example of a porous nozzle used in the present invention, and FIG. It is a bottom sectional view of a regeneration tower showing an example of a regeneration device. FIG. 5 is an assembly sectional view showing a method of installing the multi-hole nozzle of the present invention in the regeneration tower by a continuous nozzle insertion method.

In FIG. 1, a coke oven gas (COG) 1 containing hydrogen sulfide, hydrogen cyanide and the like is charged into an absorption tower 2 provided with an absorption liquid spray nozzle and a filler, and a regeneration tower 6 is provided.
In countercurrent contact with the circulating absorbent from
It is sent to the next process as 3. The absorbing liquid 4 that has absorbed hydrogen sulfide and the like is withdrawn from the liquid reservoir of the absorption tower 2 and is pumped.
At the regeneration tower 6. The oxygen-containing gas (air) 7 for regeneration is pressurized by an air blower 8 and then ejected from a perforated nozzle 9 into a liquid reservoir of a regeneration tower 6. Here, the catalyst is regenerated and oxidation of the sulfur compound and the like is performed. The regenerated absorbent 10 is circulated to the absorption tower 2 by a circulation pump 11, and the air for regeneration is discharged as waste gas 12.

In the present invention, one example of a multi-hole nozzle used for jetting the air for regeneration has a large number of jet holes 21 on the front surface of the nozzle as shown in FIGS. 2 and 3, and the jet holes 21 are provided inside the nozzle. It penetrates into the air chamber 22. In order to enhance the air dispersion efficiency, the nozzle front surface has a shape in which the center protrudes from the peripheral edge. Jet hole 21 shown in FIG.
Are arranged on the nozzle center and two concentric circles,
This concentric circle may be more.

Further, as shown in FIG. 4, the porous nozzle A in the submerged regenerating apparatus is provided on a side wall near the bottom of the regenerating tower.
When a plurality of short and long ones are alternately arranged, bubbles are more uniformly dispersed in the liquid. If the cleaning steam pipe B is connected to the air pipe of the multi-hole nozzle A, steam cleaning of the nozzle can be performed at any time without stopping the regenerating device. These multi-hole nozzles A
It is preferable to install in a circle pipe C for air supply arranged near the bottom of the regeneration tower and along the peripheral wall of the tower.

Next, an example of a construction method using the continuous nozzle insertion method will be described with reference to FIG. (1) The nozzle 32 for continuous drilling is welded to the side plate 31 of the regeneration tower. (2) The perforated valve 33 is mounted in a closed state. (3) Continuous drilling machine (not shown) for valve 33 for continuous drilling
Attach. (4) The valve 33 for continuous perforation is opened, and the tower side plate 31 is perforated. (5) After completing the continuous perforation, the valve 33 for continuous perforation is closed. (6) Remove the continuous drilling machine. (7) The nozzle set 34 (such as the multi-hole nozzle 35, the storage box 36, the steady rest 37, the stuff-in box 38, and the ejection amount adjusting valve 39) that has been assembled in advance is attached to the flange of the valve 33 for continuous drilling. (8) Open the valve 33 for continuous perforation and open the perforated nozzle 35
Insert At this time, the ejection amount adjustment valve 39 is closed,
The valve for continuous perforation 33 is kept open. At this time, the gland packing 40 of the stuff-in box 38 is tightened by the gland packing presser 41 to prevent gas-liquid leakage in the tower. (9) An air pipe (not shown) for blowing is connected to the upstream side of the ejection amount adjusting valve 39. (10) The ejection amount adjustment valve 39 is opened, air is blown into the tower, and the use of the submerged regeneration device is started.

[0022]

EXAMPLES Example 1 Wet desulfurization equipment equipped with an in-air regeneration device (processing capacity 17.5
Ten thousand Nm ³ / hr, air for regeneration amount 13,000Nm ³ / h
r) was modified so that the porous nozzle shown in FIGS. 2 and 3 was attached as shown in FIG. The underwater regeneration device has a pore diameter of 5.3m.
m, a total of 12 perforated nozzles having 24 holes were installed by the above-described continuous nozzle insertion method. When COG was desulfurized using this desulfurization equipment, the COG treatment amount was 195,000 Nm ³ / hr, and the absorbent to be regenerated was 3000 Nm ³ / h.
r, regenerating tower liquid depth 6.0m, regenerating air in liquid 1,000N
The absorption liquid was able to be regenerated to the target value at m ³ / hr and air regenerated air of 13,000 Nm ³ / hr. With this remodeling,
The COG throughput increased from 175,000 Nm ³ / hr (in-air regeneration method) to 1950 Nm ³ / hr. In addition, the operation could be continued without stopping the desulfurization equipment during the remodeling work.

Example 2 In the wet desulfurization facility modified in Example 1, the ventilation to the aerial regeneration nozzle was completely stopped, and the absorption liquid was regenerated only by the in-liquid regeneration method. Coke oven gas throughput 1
At 70,000 Nm ³ / hr, the absorbing liquid to be regenerated 3000
Nm ³ / hr, a regenerator of liquid depth 6.0 m, the absorption liquid in the liquid in the regeneration air 4,000 nm ³ / hr could play the target value. As a result, the amount of regeneration air is reduced from 13,000 Nm ³ / hr of the conventional air regeneration method to 4,000 Nm ³ / hr.
The air use efficiency was significantly improved from 5% to 20%. This makes it possible to replace the air blower with a smaller one, and the power cost can be significantly reduced.

[0024]

In the wet desulfurization equipment, the submerged regenerator equipped with the perforated nozzle of the present invention requires a smaller amount of air than the in-air regenerator, and regenerates in liquid using a conventional gas-liquid mixing type nozzle. The remodeling cost was about 1/10 of that of the equipment, and the maintenance cost was reduced. In addition, the adoption of the improved continuous nozzle insertion method enabled safe and reliable remodeling while operating the desulfurization equipment.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the concept of a wet desulfurization facility.

FIG. 2 is a side sectional view showing an example of a multi-hole nozzle.

FIG. 3 is a front view showing an example of a multi-hole nozzle.

FIG. 4 is a bottom sectional view of a regeneration tower showing an example of the submerged regeneration device of the present invention.

FIG. 5 is an assembly sectional view showing a method of installing a perforated nozzle in a regeneration tower by a continuous nozzle insertion method.

[Explanation of symbols]

 1: COG 2: Absorption tower 3: Purified COG 4: Absorption liquid 6: Regeneration tower 8: Air blower 9, A, 35: Perforated nozzle 11: Circulation pump 21: Spout 22: Air chamber 32: Nozzle for continuous perforation 33: Permanent drilling valve 34: Nozzle set 39: Ejection amount adjustment valve

Claims (2)

[Claims] 1. A hydrogen sulfide-containing gas is brought into contact with a redox catalyst-containing absorption solution in an absorption tower to absorb and remove hydrogen sulfide, and the hydrogen sulfide-containing absorption solution is contact-oxidized with an oxygen-containing gas in a regeneration tower to remove sulfur. In the wet desulfurization in which the redox catalyst is released and regenerated and the regenerated absorbent is circulated to the absorption tower, wet desulfurization is provided by installing a plurality of porous nozzles for jetting oxygen-containing gas on the bottom side wall of the regeneration tower. Submerged regenerating device. 2. A hydrogen sulfide-containing gas is brought into contact with a redox catalyst-containing absorption solution in an absorption tower to absorb and remove hydrogen sulfide, and the hydrogen sulfide-containing absorption solution is contact-oxidized with an oxygen-containing gas in a regeneration tower to remove sulfur. In wet desulfurization in which the redox catalyst is regenerated and the regenerated absorbent is circulated to the absorption tower, a plurality of mounting holes are formed in a bottom side wall of the regenerator by a continuous perforation method, and then each of the plurality of mounting holes is removed. A method for mounting a submerged regenerating apparatus in wet desulfurization, wherein a perforated nozzle for jetting oxygen-containing gas is connected to a valve for adjusting the jetting amount of oxygen-containing gas in the hole.