JPS63222005A - Purification of crude liquid sulfur - Google Patents

Abstract

PURPOSE:To efficiently remove H2S and H2Sx contained in crude liquid sulfur, by bringing a sweep gas into contact with liquid sulfur and discharging while passing crude liquid sulfur through a catalytic container and bringing into contact with a solid catalyst. CONSTITUTION:A catalytic container packed with a solid catalyst capable of decomposing polyhydrogen sulfide is set in a liquid sulfur storage tank, crude liquid sulfur containing hydrogen sulfide and polyhydrogen sulfide is introduced to the storage tank, passed through the catalytic container and brought into contact with the solid catalyst. Then sweep gas is sent to the storage tank, brought into contact with liquid sulfur and discharged while bringing the crude liquid sulfur into contact with the solid catalyst to purify the crude liquid sulfur. In introducing the crude liquid sulfur into the storage tank, liquid sulfur having passed through the catalytic container once may be circulated to the catalytic container and repeatedly brought into contact with the solid catalyst. Or the liquid sulfur may be passed through plural catalytic containers.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Purpose of the invention Industrial field of application This invention mainly uses hydrogen sulfide (H2
S) and dioxide! The present invention relates to a method for purifying crude liquid sulfur containing hydrogen sulfide and polyhydrogen sulfide (H2SX: X is a number of 2 or more), which is produced from SO2.

Elemental sulfur from the Claus unit is produced in liquid form and is stored or transported in this form for industrial use.

However, in the liquid sulfur produced by the Claus process, H2S and H2SX are usually dissolved in an amount of 200 to 800 ppm converted to H2S during the production process, and these vaporize and diffuse from the liquid sulfur during storage or transportation. , as well as the effects on the human body, there is a risk of gas explosion, so it is necessary to reduce these.

2. Description of the Related Art Various methods have been developed to remove H2S and H2SX dissolved in liquid sulfur. Mainly methods for physically removing H2S, H2S and H2S
Physicochemical methods for simultaneous removal of 2SX have also been disclosed. The main points of these are listed below.

(2) A method for mainly removing H2S (3) A method of physically removing H2S by colliding liquid sulfur with a jet against an obstacle and dispersing it in a mist (Japanese Patent Publication No. 10308/1983).

■H2S is physically removed by bringing the exhaust gas (tail gas) from the Claus device into countercurrent contact with the produced liquid sulfur (Special Publications Publication No. 5)
No. 6-7966).

Method for simultaneously removing Il, H2S, and H2SX ■ H2S is removed by blowing away the produced liquid sulfur with the final residual gas from the Claus reactor, and then ammonia, amine, etc. are added to the liquid sulfur as nitrogen compounds to remove H2SX. Convert to H2S and remove (#Publication No. 56-52847).

■H2S is converted to S by introducing an oxidizing gas (a small amount of sulfur dioxide is added) into the liquid sulfur produced from the Claus device under slight pressure, and then amines are added as nitrogen compounds to convert H2SX to H2S. Convert and remove (Japanese Patent Publication No. 56-45842).

■ Liquid sulfur from the Claus process is mixed with alumina or cobalt.
H
Remove 2S and H2SX (Special Publication No. 59-40762
issue).

■ H2S and H2 are produced by contacting liquid sulfur with oxygen-containing gas or nitrogen gas in the presence of a Ni-No catalyst.
SX is removed (JP-A No. 61-256904).

In the prior art described in ``2'', ``■-■'' and ``■'' mainly involve the removal of hydrogen sulfide, and H2SX tends to remain.

■-■, ■ is H2SX by adding nitrogen compounds to liquid sulfur.
However, the processing time is long and the additives remain in the sulfur as impurities.

(2)-(2) and (2) are technologies that mainly involve selection of a catalyst and purge gas for decomposing H2SX into H2S and 5x-t.

Normally, H2S dissolved in liquid sulfur can be removed relatively easily by blowing a sweep gas and purging it, but H2SX, which accounts for more than 50% of the total hydrogen sulfide, decomposes into H2S. Since it cannot be purged unless it is in the form of H2S and 5x-t, and its decomposition rate is slow, an appropriate catalyst is used to promote the decomposition into H2S and 5x-t according to the following formula.

H2SX: H2S+5X-1(1)] Since the reaction is an equilibrium reaction, decomposition will not proceed unless the generated H2S is discharged out of the system.

Conventionally, in order to immediately purge the H2S decomposed in the presence of a catalyst, all contactors were specially installed outside and sweep gas was blown in at the same time. Since it is required to operate under the restricted conditions of °C, sufficient attention must be paid to temperature control during operation, and there are disadvantages in terms of catalyst replacement, installation location, equipment cost, thermal economy, etc.

Problems to be Solved by the Invention The purpose of the present invention is to provide a method for purifying liquid sulfur, which solves the drawbacks of conventional methods and efficiently removes H2S and H2SX contained in crude liquid sulfur. do.

Means for Solving the Constituent Problems of the Invention The inventors believe that when refining is carried out in a storage tank of liquid sulfur, the decomposition of H2SX into H2S and 5X-1 by catalytic action and the contact with the sweep gas occur. It has been found that this process can be carried out separately from the removal of H2S, and that it is not only easier to operate while preventing catalyst dancing, but also efficient in terms of catalyst exchange, space utilization, equipment costs, heat economy, etc. The invention has been completed.

The method for purifying crude liquid sulfur containing hydrogen sulfide and polyhydrogen sulfide according to the present invention includes a r
A catalyst container in which a Lii-form catalyst is sold is placed in a liquid sulfur storage tank, and crude liquid sulfur is introduced into the storage tank and passed through the catalyst container to contact with the solid catalyst, while a sweep gas is fed into the storage tank. It is characterized by being discharged after contact with liquid sulfur.

At this time, the liquid sulfur that has once passed through the catalyst container may be circulated through the catalyst container and brought into contact with the solid catalyst repeatedly. Alternatively, the catalyst may be passed through a plurality of catalyst containers.

The contact between the sweep gas and the liquid sulfur may be such that the sweep gas passes through the surface -I- of the liquid sulfur, if the surface area of the liquid sulfur in the storage tank is sufficiently large and the contact with the sweep gas is good. Preferably, the liquid M yellow in the reservoir is sprayed into the gas phase of the reservoir or the sweep gas is bubbled into the liquid sulfur to achieve intimate contact between the sweep gas and the liquid sulfur. Of course, both may be used.

The sweep gas used is air, steam, nitrogen, or a gas having an H2S content of 1.5% or less, such as off-gas from Claus apparatus tail gas treatment (for example, Scott method) or Claus apparatus incinerator off-gas.

The catalyst container installed in the storage tank may have any shape such as cylindrical or square, and a net-shaped container can also be selected and used as appropriate.

The composition of the catalyst used here is not particularly limited, and N
Any solid catalyst other than the i-Mo catalyst can be used.

Regarding the shape, since the reaction is always in liquid sulfur, a spherical shape is preferable to avoid wear, and the diameter is 1 to 15 m.
It is preferable to have a diameter of about m.

It is important to maintain the reaction temperature in the catalyst layer, that is, the storage tank temperature, in the range of 120 to 160° C. due to the characteristics of liquid sulfur. It is most economical to use the liquid sulfur temporary storage tank at the outlet of the sulfur condenser of the Claus apparatus as the storage tank used in the present invention from the viewpoint of equipment savings and heat. The reaction pressure and force are usually normal pressure to slightly increased pressure.

The method of the present invention will be explained in detail below with reference to the accompanying drawings, but the present invention is not limited to the illustrated examples.

FIG. 1 is a diagram for explaining an example of an embodiment of the method of the present invention. A catalyst container 3 filled with a solid catalyst 2 such as a Ni-Mo system is installed in a semi-underground insulated storage tank l for storing liquid sulfur, and the crude liquid sulfur from the Claus device is transferred from a supply pipe 4 to the catalyst container 3. The liquid sulfur is supplied and passed through the catalyst container to contact the solid catalyst 2, and the liquid sulfur in the storage tank is further circulated to the catalyst container 3 by the circulation pump 5 and brought into contact with the solid catalyst 2 repeatedly. A sweep gas inlet pipe 6 is connected to the four-part side wall of the storage tank I, and a sweep gas discharge pipe 7 is connected to the opposite side wall. A part of the storage tank is roughly partitioned by a weir plate 8 to form a purified liquid sulfur storage chamber 9, in which a pump 10 for discharging purified liquid sulfur is installed.

In addition, a heater (not shown) for maintaining the temperature of the liquid sulfur in the storage tank is provided at an appropriate location.

The liquid sulfur in the storage tank 1, which is circulated by the pump 5, is sprayed above the catalyst container 3 and repeatedly contacts the solid catalyst 2 in the catalyst container. At that time, (7) H2SX in liquid sulfur
is decomposed into H2S and 5X-1.

The H2S produced by the decomposition is then vaporized when sprayed and removed by the sweep gas stream.

Through such circulation, H2S and H2SX in liquid sulfur
decreases significantly.

In this way, H2S in the liquid sulfur is released and discharged from the discharge pipe 7 together with the square sweep gas, and is treated with an incinerator or the like.

Purified liquid sulfur in an amount commensurate with the crude liquid sulfur from the Claus device sent from the supply pipe 4 overflows the weir plate 8 and moves to the purified liquid sulfur storage chamber 9, where it is transferred to the discharge pump 10.
is transferred to the outside of the tank.

The pump 5 for circulating liquid sulfur and the pump 10 for discharging purified liquid sulfur may be installed outside the storage tank or inside the storage tank, but
From the viewpoint of temperature control of the liquid sulfur, it is preferable to install a submersible pump in the storage tank.

FIG. 2 is a diagram for explaining another example of the embodiment of the method of the present invention. Sweep gas gas inlet pipe 6 is stored 461
The apparatus is substantially similar to the apparatus shown in FIG. 1, except that the sweep gas is introduced into the bottom of the liquid sulfur through a nozzle 61 to bubble the sweep gas into the liquid sulfur. In this way, H2
S purge efficiency increases.

At this time, if the sweep gas is introduced from below the catalyst container, the catalyst tends to dance, and if it is attempted to introduce gas from above the catalyst container to prevent this, a special pressurizing and sealing device is required.

FIG. 3 shows another embodiment, in which a catalyst container 3 is installed around a hollow cylinder 11, and when sweep gas is bubbled into liquid sulfur from a nozzle 61 provided at the bottom of the hollow cylinder 11, the liquid m yellow The gas rises in the hollow cylinder accompanied by air bubbles, overflows the upper edge of the hollow cylinder, and enters the catalyst container 3. This eliminates the need for a pump to circulate liquid sulfur.

The number of catalyst containers installed in the liquid sulfur storage tank is not limited to one, and may be two or more.

In the case of FIG. 4, the catalyst vessel 31.3 has a net-like side wall.
2 and 33 are placed side by side at intervals so as to partition the storage tank 1, and the crude liquid sulfur from the supply pipe 4 is fed into the catalyst containers 31, 32, .
33 in sequence. Sweep gas nozzles 61 are arranged before and after the catalyst container. In this case too, a pump for circulating liquid sulfur is not required.

Figure 5 is a view of the storage tank 1 seen from the -L direction, with catalyst containers 31, 32, and 33 installed adjacent to each other in the storage tank 1, and crude liquid sulfur from the supply pipe 4 alternately moving each catalyst container in reverse. A passage is provided for passage in the same direction, and a nozzle 61 for the sweep gas is arranged in the passage for the crude liquid sulfur.

[Example] Ni-Mo based 3 mmΦ spherical solid catalyst layer (filling amount 50
200 tons of liquid sulfur at 150° C. was poured from a Claus apparatus into an experimental apparatus as shown in FIG. 2, which had a catalyst container inside it.

The total H2S in this liquid sulfur is 320 ppm, of which H2S
X was 210 ppm. Next, liquid sulfur was circulated in contact with the catalyst layer at a ratio of 501/Hr using a liquid di pump, and 1000 Nl of air was used as a sweep gas.
/Hr was supplied.

Table 1 shows the results of analyzing the total H2S and H2SX in the liquid sulfur 1 hour, 5 hours, and 10 hours after the reaction.

[Comparative Example 1 200 ml of liquid sulfur at 150°C was charged from a Claus apparatus into the same experimental apparatus as used in Example 1, except that 50 pieces of spherical glass beads having a diameter of 3 mm were filled in the catalyst container.

The total H2S in this liquid sulfur is 310 ppm, of which H2S
X was 200PPm. Next, liquid sulfur was circulated in contact with the glass beads layer in the catalyst container at a rate of 50 cubic meters/hour using a submerged pump, and 1 liter of air was added as a sweep gas.
00ON saw/Hr was supplied.

Table 1 shows the results of analyzing the total H2S and H2SX in the liquid sulfur 1 hour, 5 hours, and 10 hours after the reaction.

(Left below) Table 1 From the results shown in Table 1, it is clear that when the liquid sulfur in the storage tank is brought into contact with the solid f', and the sweep gas is brought into contact with the liquid sulfur while the liquid sulfur is brought into contact with the catalyst, Compared to the case where sulfur is not brought into contact with the solid catalyst, the decomposition of polyhydrogen sulfide and the decrease in total H2S are remarkable.

m months In the method of the present invention, saturated with H2S and H2SX
A crude liquid 'ti, yellow, containing also H2S, is present in the storage tank and is diluted with a large amount of liquid sulfur, which has become less dissolved H2S as the purification progresses, and H2 produced by the decomposition of H2SX.
Since S is easily removed from the catalyst surface, the equilibrium of H2SX ヰ H2S + 5X-1 (1) tends to shift to the right side, and in this case, the reaction rate of H2SX production due to the reverse reaction is temperature dependent. Its formation can be suppressed if the temperature inside the storage tank is high and normal. Therefore, sweep gas is sent into the storage tank and brought into contact with liquid sulfur to produce H2S.
It is thought that H2SX can also be efficiently decomposed and removed by purging.

C9 Effects of the invention (1) Since the catalyst layer is installed inside the liquid sulfur storage tank, operation management and catalyst replacement are easy, and the site area of the equipment is reduced, equipment costs, heat loss, etc. are reduced. It is measured.

(2) By separately performing the decomposition of hydrogen sulfide using a catalyst in the liquid sulfur storage tank and the removal of the hydrogen sulfide produced by the decomposition using a sweep gas, it is easy to feed the sweep gas into the storage tank. Any gas can be used as long as it has a hydrogen sulfide content of 1.5% or more, which causes almost no wear due to catalyst movement, and is subject to restrictions on the sweep gas for the catalyst.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 3, FIG. 4, and FIG. 5 are all diagrams for explaining embodiments of the present invention. ■ = Liquid sulfur storage tank 2: Solid catalyst 3. 31, 32, 33: Catalyst container 4; Crude liquid sulfur supply v 5: Circulation pump 6: Sweep gas inlet pipe 61: Same nozzle 7: Sweep gas discharge pipe 8: Weir Plate 9: Purified liquid sulfur storage chamber

Claims (1)

[Claims] 1. A catalyst container filled with a solid catalyst capable of decomposing polyhydrogen sulfide is installed in a liquid sulfur storage tank, and crude liquid sulfur is introduced into the storage tank and passed through the catalyst container to contact the solid catalyst. In addition, a method for purifying crude liquid sulfur containing hydrogen sulfide and polyhydrogen sulfide, characterized in that a sweep gas is introduced into a storage tank, brought into contact with liquid sulfur, and then discharged. 2. The method for purifying crude liquid sulfur according to claim 1, wherein the liquid sulfur in the storage tank is circulated to the catalyst container and brought into repeated contact with the solid catalyst. 3. The method for purifying crude liquid sulfur according to claim 1 or 2, in which the liquid sulfur in the storage tank is sprayed into the gas phase of the storage tank to bring the sweep gas into close contact with the liquid sulfur. 4. The method for purifying crude liquid sulfur according to claim 1 or 2, in which the sweep gas is bubbled into the liquid sulfur in the storage tank to bring the sweep gas into close contact with the liquid sulfur.