JPS6087834A - Dry desulfurization process - Google Patents

Abstract

PURPOSE:To reduce abrasion of absorbing agent and apparatus and to improve contact efficiency of the absorbing agent with gas to be treated by performing absorption of H2S using an absorbing agent comprising a metal oxide and regeneration of the absorbing agent on a moving bed moved in the form of a thin layer. CONSTITUTION:An absorbing agent such as ZnO is introduced into an absorption tower 1 from a hopper 4 and moved downward slowly in the form of a thin layer continuously or intermittently to form a moving bed 6 of the absorbing agent. The gas 7 to be treated contg. H2S such as coal gasification gas is introduced into an absorption tower 1 from an inlet 8 of the gas and is allowed to contact at right angle with the moving bed 6 to absorb and remove H2S. The desulfurized gas is discharged from an outlet 9. An H2S absorbing agent is introduced into a regenerating tower 2 from an outlet 10 through a passage 11, and is allowed to move downward slowly in the form of a thin layer to form the moving bed 13 of the H2S absorbing agent. O2-contg. gas is introduced from an inlet 15 of regenerating gas into a regenerating tower 2 and is allowed to contact with the moving bed 13 to contact at right angle to liberate SO2, and the absorbing agent is regenerated simultaneously. SO2 is sent to a reducing tower 3 together with the regenerating gas and is transformed to a single substance sulfur.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry desulfurization method for removing HIS (hydrogen sulfide) from coal, C1 oil gasification gas, etc. In addition to reducing wear on the absorbent and equipment, dry desorption (straight direction) can reduce the installation area of the equipment by increasing the contact efficiency between the absorbent and the gas to be treated. Regarding six.

Generally, the gasified gas of coal and oil contains t1+S (hydrogen sulfide) gas as an impurity, so the above tl+s is added during the refining process to prevent air pollution and damage to various equipment. has been removed.

Conventional I-hS removal methods include wet and dry desulfurization methods, but the wet method not only requires 1C water using an alkaline absorption liquid, but also has lower thermal efficiency. Furthermore, there were concerns about secondary pollution caused by wastewater treatment.

For this reason, the dry method, which does not have the above-mentioned problems, is mainly adopted, but when using the so-called fixed bed desulfurization method, in which the absorbent is fixed and covered, continuous stable operation is not possible, and there is a risk of adhesion of the absorbent. Furthermore, there is a problem that the playback rate is extremely high.

In order to solve this problem, the so-called fluidized bed method, in which the absorbent is fluidized and the gas to be treated comes into contact with it, has been adopted, but in this case, Not only is the absorbent and equipment severely damaged, but the installation area is increased due to the need for a free board, and furthermore, the contact between the absorbent and the gas to be treated is distorted. Therefore, there is a problem of reducing the contact effectiveness key, and the current situation is that a sufficient desulfurization method V has not yet been provided.

The present invention has been devised to effectively solve the above-mentioned problems.

The purpose of the present invention is to adopt a so-called cross-flow moving bed system, and to provide an absorbent and equipment. The purpose of the present invention is to provide a dry de-M1 method that can reduce the installation area of the apparatus by reducing the contact effects between the absorbent and the gas to be treated (while also reducing wastage).

The present invention provides a method for treating a gas containing HaS, such as coal or petroleum gasification gas, with a metal oxide using IB2 sulfur.
Dry type 11f+ with 1 aS/ζ sulfide 1 extracting agent liquefied and regenerated! Ili! + 17'5 method, the absorbent was moved in a thin layer to form a moving bed, and then Mt was removed by avoiding contact of the gas to be treated with this moving layer, and then ThS was absorbed in 1ift. The above objective is achieved by moving the oxidized absorbent in a thin layer to form a moving bed and oxidizing it by contacting it with an oxygen-containing gas. The method of the present invention will be explained in detail below based on the accompanying drawings.

FIG. 1 is an IS process diagram illustrating the method of the present invention.

As shown in the figure, the Hadachibana apparatus N which actually carries out the method of the present invention brings the gas to be treated into contact with the absorbent! '-c Absorption tower 1 subjected to desulfurization treatment and absorption tower 1) The discharged sulfurized absorbent is brought into contact with an oxygen-containing gas and re-injected into 'L'? Juru play tower 2
It is mainly composed of an SO+ reducing group 3 which reduces SO+ (sulfur dioxide) recovered in the regeneration tower 2 and recovers a simple substance.

First, the absorbent zn oTj flowing down from the hopper 4 is introduced into the absorption tower 1 through the absorbent inlet 5, and is gradually moved downward continuously or intermittently in a thin layer to form a moving bed of absorbent. Form 6.

On the other hand, l'llj with oil or coal gasification residue
The gas to be treated 7 containing
? 51, and this gas flow is perpendicular to the moving bed 0! (The contact IJ is made to cross horizontally. By kneading, 1-1ts is absorbed and removed from the gas as shown in the following formula 1, and the 1j; 2 sulfur treatment of the gas to be treated is performed.

l-h 8+Zn 0-)Zll S-1-1-h O
-m And the treated gas that has been desulfurized is gas discharged 1
．． Absorbed from 19”? 1711B <': is transferred to another processing system.

The absorbent used here is a metal oxide,
! For example, crushed iron ore G, carrier + iron oxide, a mixture of fly j' tshu and iron oxide, copper oxide, zinc oxide, etc. are used.

3. The moving speed of the absorbent moving bed 6 is preferably 1 to 20 m/l+r. This is due to the fact that the moving speed of the absorbent is slow.
, the desulfurization rate decreases due to a decrease in the absorption capacity of the absorbent, and if the desulfurization rate is too early, not only will the IJ wear of the absorbent increase,
This is because the energy for heating and transport increases as the amount of processing in the regeneration tower increases, which becomes uneconomical.

Further, the H+S content of the gas to be treated 7 introduced into the absorption tower 1 is maintained at about 460° C. at an average of 3000 ppm (based on the standard).

The gas velocity in the absorption tower 1 is 0.05 to 5 m/'
SOC is preferred.

This is because although the gas velocity is slow, the desulfurization rate is low because of the gas flow only.If the gas velocity is high, the desulfurization rate may not be sufficient due to the reaction rate. Not only will the 8-party M [ratio] fall to 6, but the loss of pressure will increase, making it uneconomical.

The temperature of the reaction mixture in the absorption tower 1 will vary depending on the type of absorbent used, but for example, if iron oxide is used as the absorbent, the temperature will be maintained at approximately 400-550°C. cover This is due to the parallel relationship between iron oxide, which means that as the temperature rises, the reaction rate decreases, and as the humidity decreases, the reaction rate decreases.
This is because the desulfurization rate decreases as well.

Further, it is desirable that the particle size of the absorbent range from about 0.5 to 5 imn+. This is because as the particle size decreases, the pressure drop increases, and as the particle size becomes smaller, the reaction rate decreases. This means that the l rate will decrease.

Next, the sulfurized absorbent that has been sulfurized or reduced in the absorption tower 1 is discharged outside from the U+ outlet 10 at the bottom of the absorption tower 11, and the passage 11
Transfer to CI raw JiS 2 via (). Next, this lIIi! f-absorbent total absorbent? Set at the top of S2 (
Introduction of absorbent [112 Kauko I? S 2 and gradually moved downward in a thin layer, either continuously or intermittently, to form a moving bed 13 of sulfurized absorbent.

On the other hand, oxygen-containing gas such as air or other regeneration gas is 1/1
A regeneration gas is introduced into the column 2 from 115, and this gas flow is brought into contact with the moving bed 13 at right angles.
, cross this horizontally.

As a result, as shown in formula 2 below, the la absorbent becomes about 8
It is oxidized at 00°C to release Sol and is regenerated into the original metal oxide absorbent.

2211 S-130+ -)22+10-l-2SO
+ =-+2+Here, the moving speed of the sulfurized absorbent within the regeneration 162 is approximately 20+n/l]r or less. This is because if the moving speed is high, regeneration will be insufficient, the absorbent will wear out more, and furthermore, the heating energy will increase, which will be uneconomical.

Well, Ic-, the gas velocity in the regeneration tower 2 is about 0.05・5
m/5eIC range. This is because, as mentioned above, when the gas velocity is high, pressure loss increases.

Further, the reaction iQ Im in the regeneration tower 2 ranges from about 550 to 800°C, depending on the type of absorbent used. This is because if the reaction temperature is high, there will be problems such as sintering, whereas if the reaction temperature is low, regeneration may take a long time or may be insufficient.

The absorbent thus regenerated is discharged 171 out of the absorbent discharge port 16 provided at the bottom of the regenerated JM 2 1M. Then, the worn and powdered absorbent is sorted by a sieve 17 and sent out of the system, while most of the remaining absorbent is directed to the absorption tower 1 through a passage 18 (J is transferred). , It is strange for the desulfurization treatment of the gas to be remelted!
It is circulated and introduced into C1.

At this time, the missing amount of absorbent is sequentially supplied from the small brim 4.

On the other hand, Sol generated by oxidizing the sulfurized absorbent in the raw tower 2 is discharged from the regenerated gas outlet 119 to the outside of the tower along with the regenerated gas, and the 'fl 20 to /1. and transferred to SO+reduction jha3. (l] °l', regeneration gas containing sO+ is SO
+Reduction j33 reduction”? 5 gas is introduced into this plant from 21, while a reducing agent made of coal or carbon is introduced into this pit 3 from a hopper 23 via a main contractor 24. A filling layer 25 of reducing agent is formed by filling nine layers.

Then, the regeneration gas comes into contact with the reducing agent gradually moving lower in the tower, and the Sol contained therein is reduced.
Large 615 minutes will be a single r-oh.

The generated single unit A20 (installed at the top of the reduction tower 3)
The used reducing agent 28 is discharged from the output 127, while the used reducing agent 28 is discharged outside the column from the output 129.

In addition, particularly when a high sulfur yield is desired, a conventional Claus reactor or the like is fitted to the reduction column 3.

In this way, the gas to be treated is passed in contact with the moving bed 6 of the absorbent that is continuously or intermittently moved downward in the absorption tower 1 so as to cover the moving bed 6, thereby carrying out the 1;2 sulfur treatment. As a result, the absorbent is not fluidized as compared to the conventional fluidized bed system, and therefore, wear of the absorbent and type 1 can be avoided as much as possible. This is because a similar moving bed is formed not only in the absorption tower 1 but also in the regeneration tower 2 to perform 1-T raw treatment, so the same effect is achieved, and the synergistic effect of these It can greatly prevent wear on the chemical equipment.

In addition, in both the absorption tower 1 and the regeneration tower 2, the gas flow passes orthogonally through the thin moving bed.
There is no need to fluidize the absorbent with a gas flow (at the same flow rate as in the conventional example), and therefore, it is possible to reduce the pressure loss and also reduce the vibration of the loading body. Preventing it is C.

Furthermore, since the gas flow can be uniformly passed through the entire area of the fluidized bed formed, unlike the conventional fluidized bed type, the gas flow (diversion) is created. By increasing the contact efficiency, the response rate will increase.

In addition, since the gas flow is brought into contact with the moving body formed by moving the absorbent downward continuously or intermittently, unlike the conventional fixed desulfurization method, continuous desulfurization treatment can be performed.
Fusion of the absorbent can be prevented.

Next, the results obtained based on the above method will be shown.

Absorption j3 OJ, and regeneration J? ) is as follows.

(1) Desulfurization conditions (absorption tower) Gas composition l-h S: 30001 IDm.

11+: 13%.

1-h'o: 10%.

CO: 1 (3%.

CO2: 10%.

N+: [3aρ Temperature 460℃ Absorbent hematite, average particle size: 3 rivers Absorbent transfer speed 3m/old +1t211I rate 95% (2) Regeneration conditions (regeneration tower) Gas composition 02: 6%, N+: 13FI Temperature A: 800°C Absorbent transfer speed: 5 m/l+r Regeneration rate: 99% In summary, the method of the present invention can exhibit the following excellent effects.

(1) Crossing the gas flow perpendicularly to the moving bed of absorbent
Since I have done le+ processing and playback processing in one,
Wear of the absorbent and loading materials can be significantly reduced.

(2) Since the gas flow is uniformly passed through the moving bed formed in a thin layer, pressure loss can be significantly reduced.
It is possible to improve the absorption efficiency or the contact efficiency with the gas flow, and the desulfurization or regeneration efficiency can be improved.

(3) Since the free board required in the conventional fluidized bed method can be eliminated, the equipment itself can be made smaller;
The installation area is small (can be covered).

(/I) Since the vibration of the device itself is reduced compared to the fluidized bed method, the structure bar 1 can be easily formed.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing a desulfurization regeneration process to explain Mizumoto Akikata v1. In the figure, 1 is an absorption tower, 2 is a regeneration tower, 3 is an SC2 reduction tower, 6 is a moving bed of LJ absorbent, 7 is a gas to be treated, 13 is a moving bed of sulfurized absorbent, and 14 is an oxygen It's gas. Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Representative Patent Attorney
Group Nobuo Tani

Claims (1)

[Claims] ? 'i The gas to be treated containing 1128 such as carbon dioxide gas,
The 1-hs in the gas to be treated is absorbed and removed by contacting with an absorbent made of metal oxide, and the I-h
Oxidize and regenerate the sulfurized absorbent that has absorbed s.
In the dry desulfurization method described above, the absorbent is moved in a thin layer to form a moving bed of the absorbent, and the gas to be treated is brought into contact with the moving bed to desulfurize the gas to be treated, and then, When the above sulfurized absorbent that has absorbed I-1+S is moved in a thin layer to form a moving body of sulfurized absorbent,
A dry desulfurization method characterized in that the movable bed is brought into contact with an oxygen-containing gas to separate and remove A from the sulfurized absorbent, and this is made into a regenerating vine.