阅读说明：本技术 硫化氢的制造方法及硫的回收方法 (Method for producing hydrogen sulfide and method for recovering sulfur ) 是由 仲田佳广 于 2018-12-21 设计创作，主要内容包括：本发明的目的在于提供能高效地回收硫的硫化氢的制造方法。该制造方法是由硫及氢制造硫化氢的方法,其包括下述工序：(1)反应工序,使硫及氢反应,得到粗制硫化氢气体；(2)纯化工序,使前述粗制硫化氢气体、与脂肪族低级醇在填充塔内接触,使该粗制硫化氢气体中包含的硫析出,从而将该粗制硫化氢气体纯化；(3)排出工序,将前述纯化工序中得到的硫的脂肪族低级醇悬浮液从前述填充塔内排出；和(4)过滤工序,用过滤器对前述硫的脂肪族低级醇悬浮液进行过滤,从而得到硫的滤饼,其中,前述过滤器20为旋转过滤器22或叶片过滤器。(The purpose of the present invention is to provide a method for producing hydrogen sulfide, which enables efficient recovery of sulfur. The production method is a method for producing hydrogen sulfide from sulfur and hydrogen, and comprises the following steps: (1) a reaction step of reacting sulfur and hydrogen to obtain a crude hydrogen sulfide gas; (2) a purification step of contacting the crude hydrogen sulfide gas with an aliphatic lower alcohol in a packed column to precipitate sulfur contained in the crude hydrogen sulfide gas, thereby purifying the crude hydrogen sulfide gas; (3) a discharge step of discharging the aliphatic lower alcohol suspension of sulfur obtained in the purification step from the packed column; and (4) a filtration step of filtering the sulfur-containing aliphatic lower alcohol suspension with a filter to obtain a sulfur cake, wherein the filter 20 is a rotary filter 22 or a vane filter.)

1. A method for producing hydrogen sulfide from sulfur and hydrogen, comprising the steps of:

a reaction step of reacting sulfur and hydrogen to obtain a crude hydrogen sulfide gas;

a purification step of contacting the crude hydrogen sulfide gas with an aliphatic lower alcohol in a packed column to precipitate sulfur contained in the crude hydrogen sulfide gas, thereby purifying the crude hydrogen sulfide gas;

a discharging step of discharging the aliphatic lower alcohol suspension of sulfur obtained in the purification step from the packed column; and

a filtration step of filtering the aliphatic lower alcohol suspension of sulfur with a filter to obtain a sulfur cake,

wherein the filter is a rotary filter or a vane filter.

2. The method of claim 1, wherein the filter is the rotary filter.

3. A method for recovering sulfur from a crude hydrogen sulfide gas containing the sulfur, comprising the steps of:

a purification step of contacting the crude hydrogen sulfide gas with an aliphatic lower alcohol in a packed column to precipitate sulfur contained in the crude hydrogen sulfide gas, thereby purifying the crude hydrogen sulfide gas;

a discharging step of discharging the aliphatic lower alcohol suspension of sulfur obtained in the purification step from the packed column; and

a filtration step of filtering the aliphatic lower alcohol suspension of sulfur with a filter to obtain a sulfur cake,

wherein the filter is a rotary filter or a vane filter.

Technical Field

The present invention relates to a method for producing hydrogen sulfide and a method for recovering sulfur.

Background

Hydrogen sulfide is used for production of organic sulfur compounds such as methyl mercaptan and thioglycolic acid. Hydrogen sulfide is in a liquid or vapor phase and is produced by reacting sulfur with hydrogen.

The crude hydrogen sulfide gas obtained by this reaction may contain impurities such as sulfur as a raw material in addition to hydrogen sulfide. Therefore, in order to remove impurities from the crude hydrogen sulfide gas and use the hydrogen sulfide for the above-described production, a method of purifying the crude hydrogen sulfide gas has been studied (for example, patent document 1).

In the method for purifying hydrogen sulfide gas disclosed in patent document 1, crude hydrogen sulfide gas is brought into contact with alcohol in a packed column. By this contact, sulfur is incorporated into the alcohol in a powder form, and then the sulfur in the powder form is attached to the packed portion of the packed tower, whereby sulfur is removed from the crude hydrogen sulfide gas.

Sulfur is a feedstock for hydrogen sulfide. Therefore, in the purification method disclosed in patent document 1, from the viewpoint of reuse of sulfur, sulfur adhering to the packed section of the packed column is recovered.

Disclosure of Invention

Problems to be solved by the invention

As described above, in the purification method disclosed in patent document 1, sulfur adhering to the packed portion is recovered. However, it is a practical matter that a part of sulfur remains in the alcohol without adhering to the packed portion, and all of the sulfur contained in the crude hydrogen sulfide gas cannot be recovered.

If the alcohol in which sulfur remains is continuously used, the sulfur may block the piping.

Further, when an alcohol containing sulfur is treated as a waste liquid, not only the recovery rate of sulfur cannot be improved, but also the disposal of sulfur may have an adverse effect on the environment.

The sulfur remaining in the alcohol contains sulfur having a small particle size, and the sulfur having a small particle size tends to be suspended in the liquid without settling. Therefore, it is difficult to recover all the sulfur remaining in the alcohol by a solid-liquid separation method such as sedimentation or centrifugal separation.

Patent document 1 describes in detail a technique for recovering sulfur adhering to a filler, but does not mention that sulfur remains in an alcohol. That is, patent document 1 does not disclose a technique for recovering sulfur remaining in alcohol. In a process for producing hydrogen sulfide from sulfur and hydrogen, it is desired to further improve the recovery rate of sulfur.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for producing hydrogen sulfide and a method for recovering sulfur, which can efficiently recover sulfur.

Means for solving the problems

The present inventors have conducted extensive studies on a method for recovering sulfur from an alcohol suspension of sulfur obtained by purifying a crude hydrogen sulfide gas containing sulfur, among methods for producing hydrogen sulfide from sulfur and hydrogen, and as a result, have found that sulfur can be recovered efficiently by filtering an alcohol suspension of sulfur with a specific filter, and have completed the present invention.

That is, the present invention is a method for producing hydrogen sulfide from sulfur and hydrogen, comprising the steps of:

(1) a reaction step of reacting sulfur and hydrogen to obtain a crude hydrogen sulfide gas;

(2) a purification step of contacting the crude hydrogen sulfide gas with an aliphatic lower alcohol in a packed column to precipitate sulfur contained in the crude hydrogen sulfide gas, thereby purifying the crude hydrogen sulfide gas;

(3) a discharge step of discharging the aliphatic lower alcohol suspension of sulfur obtained in the purification step from the packed column; and

(4) a filtration step of obtaining a cake of sulfur (cake) by filtering the aliphatic lower alcohol suspension of sulfur with a filter,

wherein the filter is a rotary filter or a vane filter.

In this method for producing hydrogen sulfide, a sulfur aliphatic lower alcohol suspension obtained by purifying a crude hydrogen sulfide gas using an aliphatic lower alcohol is filtered to obtain a sulfur cake. When the cake of sulfur is subjected to a treatment such as heat drying, sulfur which can be reused as a raw material can be obtained. In particular, since a rotary filter or a vane filter is used as a filter when filtering an aliphatic lower alcohol suspension of sulfur, sulfur having a small particle size, which is difficult to recover by a solid-liquid separation method such as sedimentation or centrifugal separation, can be recovered. The filtrate discharged from the filter contains no sulfur. In this production method, sulfur can be efficiently recovered, and the burden on the environment can be reduced. The filter is preferably the rotary filter from the viewpoint of efficiently recovering sulfur.

From another aspect, the present invention is a method for recovering sulfur from a crude hydrogen sulfide gas containing the sulfur, comprising the steps of:

(1) a purification step of contacting the crude hydrogen sulfide gas with an aliphatic lower alcohol in a packed column to precipitate sulfur contained in the crude hydrogen sulfide gas, thereby purifying the crude hydrogen sulfide gas;

(2) a discharge step of discharging the aliphatic lower alcohol suspension of sulfur obtained in the purification step from the packed column; and

(3) a filtration step of filtering the aliphatic lower alcohol suspension of sulfur with a filter to obtain a sulfur cake,

wherein the filter is a rotary filter or a vane filter.

In the above-mentioned method for recovering sulfur, similarly to the above-mentioned method for producing hydrogen sulfide, a cake of sulfur is obtained by filtering a suspension of sulfur in aliphatic lower alcohol, which is obtained by bringing a crude hydrogen sulfide gas into contact with aliphatic lower alcohol. When the cake of sulfur is subjected to a treatment such as heat drying, sulfur which can be reused as a raw material can be obtained. In particular, since a rotary filter or a vane filter is used as a filter when filtering an aliphatic lower alcohol suspension of sulfur, sulfur having a small particle size, which is difficult to recover by a solid-liquid separation method such as sedimentation or centrifugal separation, can be recovered. The filtrate discharged from the filter contains no sulfur. The recovery method can not only recover sulfur efficiently, but also reduce the burden on the environment. The filter is preferably the rotary filter from the viewpoint of efficiently recovering sulfur.

ADVANTAGEOUS EFFECTS OF INVENTION

As is apparent from the above description, the method for producing hydrogen sulfide and the method for recovering sulfur according to the present invention can efficiently recover sulfur and reduce the burden on the environment.

Drawings

Fig. 1 is a schematic view showing a packed column used in a method for producing hydrogen sulfide according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a filter for filtering a sulfur aliphatic lower alcohol suspension recovered from the packed column of FIG. 1.

Detailed Description

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings as appropriate.

The method for producing hydrogen sulfide of the present invention includes a reaction step, a purification step, a discharge step, a filtration step, and a drying step. The contents of the respective steps are explained below.

[ reaction Process ]

In the reaction step, sulfur and hydrogen are reacted to produce hydrogen sulfide. In this production method, excess sulfur is used to generate hydrogen sulfide. Therefore, the gas obtained by reacting sulfur and hydrogen contains excess sulfur in addition to hydrogen sulfide. In the present invention, a gas obtained by reacting sulfur and hydrogen and containing sulfur in addition to hydrogen sulfide is referred to as a crude hydrogen sulfide gas. In this reaction step, excess sulfur and hydrogen are reacted to obtain a crude hydrogen sulfide gas containing unreacted sulfur.

In this production method, the crude hydrogen sulfide gas can be obtained by supplying gaseous sulfur and hydrogen gas to a reactor (not shown) filled with a catalyst and reacting them, and in the present invention, the method for producing the crude hydrogen sulfide gas is not particularly limited. In this production method, the molar ratio of sulfur atoms to hydrogen molecules in the raw material gas supplied to the reactor is preferably 1 to 1.5, more preferably 1 to 1.3, from the viewpoint of efficiently producing hydrogen sulfide.

[ purification Process ]

In the purification step, the crude hydrogen sulfide gas obtained in the reaction step is purified. In this production method, the apparatus 2 shown in fig. 1 is used to purify the crude hydrogen sulfide gas.

The apparatus 2 is provided with a packed column 4. The packed column 4 includes a packing section 6. Although not shown, the filling part 6 is filled with raschig rings.

In this purification step, the crude hydrogen sulfide gas is supplied to the packed column 4. The crude hydrogen sulfide gas is introduced into the packed column 4 from the lower part of the packed column 4. Aliphatic lower alcohol is also supplied to the packed column 4. The aliphatic lower alcohol is introduced into the packed column 4 from the lower part of the packed column 4, and then repeatedly circulated in the packed column 4 through the circulation line 10 by the pump 8.

As described above, in this production method, the aliphatic lower alcohol is supplied to the packed column 4.

In the present invention, the aliphatic lower alcohol means an aliphatic alcohol having 5 or less carbon atoms. Examples of the aliphatic lower alcohol include methanol, ethanol, and propanol. From the viewpoint of easy handling, methanol is preferred as the aliphatic lower alcohol. In particular, methanol may be used for the production of methyl mercaptan. Therefore, when hydrogen sulfide is used as a raw material of methyl mercaptan, methanol is preferable as the aliphatic lower alcohol.

In this production method, an aliphatic lower alcohol (hereinafter, may be referred to as an alcohol) may be used in admixture with water, if necessary. In this case, examples of water that can be used in combination with alcohol include pure water, ion-exchanged water, tap water, and industrial water. When methanol is used as the alcohol, the ratio of the amount of methanol to the total amount of the mixed liquid of methanol and water is set to 30% by mass or more.

In this purification step, the crude hydrogen sulfide gas is brought into contact with an alcohol in the packed column 4. By this contact, sulfur contained in the crude hydrogen sulfide gas is precipitated in a crystalline form. In the purification step, the crude hydrogen sulfide gas is brought into contact with the alcohol at a temperature in the range of normal temperature to 40 ℃.

In the purification step, the crystallized sulfur is taken into alcohol to obtain an alcohol suspension of the crystallized sulfur suspended in alcohol, that is, an alcohol suspension of sulfur. Thereby, sulfur can be removed from the crude hydrogen sulfide gas.

In this production method, the crude hydrogen sulfide gas may contain hydrogen polysulfide in addition to hydrogen sulfide and sulfur. Hydrogen polysulfide decomposes into hydrogen sulfide and sulfur upon contact with an alcohol. Therefore, when hydrogen polysulfide is contained in the crude hydrogen sulfide gas, sulfur derived from the hydrogen polysulfide gas is contained in the alcohol suspension of sulfur obtained in the purification step.

In this purification step, the crude hydrogen sulfide gas from which sulfur has been removed (hereinafter, sometimes referred to as "quasi-purified hydrogen sulfide gas") is discharged from the upper part of the packed column 4. As described above, the crude hydrogen sulfide gas is contacted with an alcohol. Therefore, the hydrogen sulfide gas to be purified contains a vapor pressure amount of alcohol.

In this production method, the quasi-purified hydrogen sulfide gas is cooled in the condenser 12 whose temperature has been adjusted to the range of-5 ℃ to 5 ℃, and the alcohol having the vapor pressure amount contained in the quasi-purified hydrogen sulfide gas is condensed. Thereby, the alcohol is removed from the quasi-purified hydrogen sulfide gas, and the hydrogen sulfide is discharged as a purified hydrogen sulfide gas from the condenser 12.

In this purification step, the crude hydrogen sulfide gas is purified by bringing the crude hydrogen sulfide gas into contact with an alcohol in the packed column 4 to precipitate sulfur contained in the crude hydrogen sulfide gas.

As described above, in the purification step, an alcohol suspension of sulfur (hereinafter, sometimes referred to as a suspension) is obtained. In this purification step, the suspension passes through the packing section 6. By this passage, the crystallized sulfur contained in the suspension adheres to the filling portion 6. In this facility 2, the suspension is repeatedly circulated through the packed column 4 via the circulation line 10, and therefore sulfur is accumulated in the packed section 6. Therefore, in this facility 2, the sulfur adhering to the packed section 6 can be appropriately recovered in consideration of the operation condition of the packed column 4 and the like. In this production method, the suspension repeatedly circulated in the packed column 4 is discharged from the packed column 4 in order to recover the sulfur adhering to the packed section 6.

[ discharging step ]

In the discharging step, the supply of the crude hydrogen sulfide gas and the alcohol, and the circulation of the alcohol and/or the suspension are stopped. After the stop, the suspension was discharged from the packed column 4. In this production method, after the suspension is discharged, water is charged into the packed column 4, and the inside of the packed column 4 is washed. After washing, the water used for washing (hereinafter, sometimes referred to as "washing water") is discharged from the packed tower 4. A part or all of the discharged washing water is mixed with the suspension.

In this production method, the suspension discharged from the packed column 4 contains sulfur that has not adhered to the packed section 6. The sulfur content in the suspension discharged from the packed column 4 is usually in the range of 0.1 mass% to 7.5 mass%. In the present invention, the sulfur content can be obtained by a heat reduction method.

In this production method, after the suspension is discharged from the packed column 4, steam is supplied to a jacket 14 provided outside the packed section 6 to heat the packed section 6. Further, steam is supplied into the packed column 4 to melt the sulfur adhering to the inside of the packed column 4. The molten sulfur flows down and is recovered in a tank 18 heated by supplying steam to the jacket 16. In this production method, the sulfur adhering to the inside of the packed column 4 is recovered by the operation as described above. In this production method, the temperature of the steam supplied to the jacket 14 of the packed section 6, the steam supplied to the inside of the packed column 4, and the steam supplied to the jacket 16 of the tank 18 is preferably set in the range of 130 to 160 ℃.

As described above, in this production method, the timing of recovering sulfur can be appropriately determined in consideration of the operation of the packed column 4 and the like. Specifically, the pressure difference between the bottom and top of the packed column 4 is monitored, and the timing of sulfur recovery is determined in consideration of the clogging.

As described above, in the discharge step, the suspension obtained in the purification step is discharged from the packed column 4. In the manufacturing method, the suspension is filtered using a filter.

[ filtration Process ]

In the filtration step, the filter 20 shown in fig. 2 is used to filter the suspension recovered from the packed tower 4. Hereinafter, the filter 20 will be described.

In this manufacturing method, the rotary filter 22 is used as the filter 20. The rotary filter 22 includes a cylindrical drum (drum)24, a stirring section 26, and a plurality of filter plates 28 (5 in the drawing). In the rotary filter 22, a space between the stirring portion 26 and the filter plate 28 inside the drum 24 is referred to as a filter chamber 30.

In the rotary filter 22, the stirring section 26 is provided in the drum 24. The stirring section 26 includes a plurality of stirring plates 32 (6 in the drawing) and a drive shaft 34. The plurality of agitating plates 32 are fixed to a drive shaft 34. The agitating plates 32 are disposed at intervals along the drive shaft 34. The rotary filter 22 is configured to rotate the agitating plate 32 by rotating the drive shaft 34 with a motor (not shown).

In the rotary filter 22, a plurality of filter plates 28 protrude inward from the inner surface of the drum 24. The filter plate 28 is arranged in such a way that it is located between 2 stirring plates 32. Although not shown, the filter plate 28 has a structure in which filter materials are attached to both sides of a support plate fixed to the inner surface of the drum 24 via filter material reinforcing plates such as metal meshes.

In this manufacturing method, the normal temperature suspension is supplied under pressure from the supply port 36. The suspension moves through the filter plates 28, within the filter chamber 30, towards the discharge opening 38 while being agitated by the agitating plate 32. During this movement, the suspension is filtered by the filter plates 28 and the cake of sulphur, as a concentrate, is discharged from the discharge 38. Moreover, the filtrate obtained by filtering the suspension is discharged through the support plate of the filter plate 28. Since the filter medium capable of capturing sulfur having a small particle size contained in the suspension is used as the filter medium, the filtrate obtained by filtering the suspension does not contain sulfur. In the production method, the filtrate is treated as wastewater.

The operating conditions of the rotary filter in the production method are, for example, 0.10 to 50.0m in the filtration area²The rotary filter 22 in the range of (1) above, wherein the supply pressure of the suspension is set in the range of 0.1 to 1.0 MPaG. Every 1m²The amount of the filter area is 0.5 to 50.0 m/hr³Is set within the range of (1). The temperature in the filtering chamber 30 is usually set within the range of 0 to 40 ℃. The torque of the stirring section 26 is set within the range of 0.5 to 100.0 kW. The filter medium can be suitably selected from corrosion-resistant materials, and examples of the material include synthetic fibers such as polypropylene and polyester, and metals such as stainless steel. When a synthetic fiber filter cloth is used, it is preferable to use a filter cloth having an air permeability of 0.03 to 1.0cm³/cm²S filter cloth. When the metal mesh is used, it is preferable to use a metal mesh of about 40 to 400 mesh.

The Rotary Filter 22 is a pressure-type Rotary Filter, the Rotary Filter 22 is a pressure-type Filter, and when the suspension is supplied to the Rotary Filter 22, a sulfur cake is continuously obtained, the Rotary Filter 22 is a pressure-type continuous Filter, and such a Rotary Filter 22 may be, for example, a "Rotary Filter (Rotary Filter)" manufactured by Hiroshima Metal & Machinery co., L td..

As a pressure type filter that can be industrially used, there is a vane filter in addition to the rotary filter 22. In this manufacturing method, the vane filter can be used as the filter 20.

In the vane Filter, the suspension supplied under pressure is filtered through the Filter plates, and a cake of sulfur as a concentrate is deposited on the Filter plates, and the filtrate is discharged through the shaft, the supply of the suspension is stopped at a point of time when the cake of sulfur is deposited to a certain extent, and the shaft is rotated, whereby the cake of sulfur deposited on the Filter plates is scattered from the Filter plates by a centrifugal force, and the cake of sulfur is collected.

[ drying Process ]

In this production method, the cake of sulfur obtained in the filtration step is supplied to the heating drum 40. In the heated drum 40, the cake of sulfur is dried.

Outside the heating drum 40, a jacket 42 is provided. Although not shown, a spiral pipe is provided inside the heating drum 40. Steam is supplied to the jacket 42 and the spiral pipe, respectively. Thereby, the heating drum 40 is heated. In this manufacturing method, the temperature of the steam supplied to the jacket 42 and the temperature of the steam supplied to the spiral pipe are preferably set within a range of 130 to 160 ℃.

In this manufacturing method, a cake of sulfur is heated in a heating drum 40. Thereby, the cake of sulfur was dried to obtain sulfur. This sulfur is reused as a raw material of hydrogen sulfide together with the sulfur recovered from the packed column 4. In this production method, the heating time for drying is set within a range of 10 hours to 100 hours.

In this production method, a suspension discharged after purification of crude hydrogen sulfide is filtered to obtain a sulfur cake. When the cake of sulfur is subjected to a treatment such as heat drying, sulfur which can be reused as a raw material can be obtained. In particular, since the rotary filter 22 or the vane filter is used as the filter 20 when filtering the suspension, sulfur having a small particle size, which is difficult to recover by a solid-liquid separation method such as sedimentation or centrifugal separation, can be recovered. The filtrate discharged from the filter 20 contains no sulfur. In this production method, sulfur can be efficiently recovered, and the burden on the environment can be reduced. From the viewpoint of efficiently recovering sulfur, the filter 20 is preferably a rotary filter 22 which is a pressurized and continuous filter.

In this production method, if the sulfur content in the cake is too low, the amount of steam used in the drying step increases. From this viewpoint, the sulfur content in the cake is preferably 10% by mass or more, and more preferably 20% by mass or more. If the sulfur content in the filter cake is too high, the filter cake hardens, and the discharge of the filter cake may become difficult. From this viewpoint, the sulfur content in the cake is preferably 60% by mass or less, and more preferably 50% by mass or less.

The aforementioned method for producing hydrogen sulfide includes a method for recovering sulfur from a crude hydrogen sulfide gas containing sulfur. That is, from another viewpoint, the present invention is a method for recovering sulfur from a crude hydrogen sulfide gas containing the sulfur. The method for recovering sulfur of the present invention includes the aforementioned purification step, discharge step, and filtration step. The method for recovering sulfur of the present invention is suitable as the method for recovering sulfur in the method for producing hydrogen sulfide of the present invention as described above, but the scope of application thereof is not limited thereto.

As is clear from the above description, in the method for producing hydrogen sulfide and the method for recovering sulfur of the present invention, sulfur can be efficiently recovered.