JPH11116212A - Process for recovering sulfur from acidic gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for stably recovering a high quality sulfur at a high yield by treating an acidic gas containing a large quantity of carbon dioxide, the low concentration hydrogen sulfide and containing large quantity of a hydrocarbon compound. SOLUTION: The process comprises a combustion reaction step, a Claus reaction step, a reduction step and a direct oxidation step. In a combustion reaction furnace, a reaction gas containing sulfur by burning the acidic gas at >=1350 deg.C by supplying the quantity of hydrocarbon compd. in the acid gas, the quantity of hydrogen sulfide in a specified ratio of hydrogen sulfide in the acidic gas and the quantity of air necessary for burning the whole quantity of the hydrocarbon compound and the sulfur compound, and a reduction gas containing sulfur dioxide generated by the reaction of hydrogen sulfide with carbon dioxide, are produced and next, the produced sulfur is separated. In the Claus reaction step, a remaining gas after sulfur is separated is supplied to a Claus reaction catalytic layer to react and the produced sulfur is separated. In the reduction step, the remaining gas after sulfur is separated is supplied to a reduction catalytic layer to reduce sulfur dioxide in the gas to hydrogen sulfide. In the direct oxidation step, air is supplied to the gas passed through the reduction step and these gases are fed to the direct oxidation catalytic layer to produce sulfur, and sulfur is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering sulfur from an acid gas, and more particularly to a method for recovering sulfur from an acid gas having a high carbon dioxide concentration and therefore a low hydrogen sulfide concentration and a high hydrocarbon compound content. It relates to the method of collection.

[0002]

2. Description of the Related Art Raw natural gas collected from gas fields contains various sulfur compounds such as hydrogen sulfide in addition to light hydrocarbons. Therefore, in general, the raw material natural gas is transported to a consuming area as a purified natural gas after sulfur compounds are removed at the producing area. Further, when the raw natural gas contains carbon dioxide, it is necessary to remove the carbon dioxide and transport it to the consuming area. On the other hand, the removed sulfur compounds are recovered as sulfur in order to prevent environmental pollution. In order to recover sulfur from raw natural gas and purify sulfur-free natural gas, first use an absorption method such as the sulfinol method to convert acidic gas containing sulfur compounds such as hydrogen sulfide into raw natural gas. And then a sulfur recovery step of recovering sulfur from the acid gas by the Claus reaction method. As sulfur compounds contained in natural gas, besides hydrogen sulfide, for example, mercaptan, CO
S, sulfur dioxide, thiophene and the like can be mentioned.
In this specification, the acidic gas refers to a gas containing hydrogen sulfide as an acidic gas, and the non-hydrogen sulfide-based sulfur compound refers to a sulfur compound other than hydrogen sulfide, such as mercaptan, COS, sulfur dioxide, and thiophene.

[0003] The Claus method comprises a hydrogen sulfide oxidation step in a first-stage reaction furnace and a sulfur production reaction step in a second-stage reaction tank. In the reaction furnace, as shown in reaction formula 1, hydrogen sulfide is burned with oxygen to generate sulfur dioxide, and as shown in reaction formula 2, hydrogen sulfide and sulfur dioxide are reacted to generate sulfur. Two reactions with the reaction proceed. In the sulfur production reaction step, hydrogen sulfide and sulfur dioxide are mixed in a volume ratio of 2: 1 and sent to the reaction tank, where the reaction tank is under a non-catalyst (high-temperature reaction zone) and under a catalyst (low-temperature reaction). Region), the reactions shown in Reaction Formulas 2 to 4 proceed. The reaction formulas (2) to (4) are reversible reactions. H ₂ S + 3/2 O ₂ → SO ₂ + 2 H ₂ O + 123,938 kcal / g-mol-H ₂ S (1) 2 H ₂ S + SO ₂ → 3/2 S ₂ + 2 H ₂ O −5,737 kcal / g-mol -H ₂ S (2) 2 S ₂ → S ₆ +65.28 kcal / g-mol-S ₆ (3) 4 S ₂ → S ₈ +65.28 kcal / g-mol-S ₈ (4)

[0004] If the concentration of carbon dioxide in the acid gas flowing out of the acid gas separation step is not very high, for example, if the concentration of hydrogen sulfide is 60% by volume or more, conventionally, in the sulfur recovery step, the Claus feed reaction of the total supply method has been used. Sulfur is recovered from acid gas by the method. Fig. 3 (a)
As shown in the figure, the entire amount of the acid gas is sent to the reactor, and the ratio of hydrogen sulfide: sulfur dioxide is adjusted to be 2: 1.
Hydrogen sulfide is partially burned in a reactor to generate sulfur, and the generated sulfur is recovered. Then, the remaining gas is produced by a non-catalytic Claus reaction in a high-temperature reaction zone and further by a catalytic Claus reaction in a low-temperature reaction zone to generate sulfur, and the generated sulfur is recovered by condensation and separation by a condenser. It is.

On the other hand, in the case where an acidic gas having a carbon dioxide concentration of 40% or more, that is, an acidic gas contains 30 to 60% by volume of hydrogen sulfide, if the sulfur is recovered by a full-amount supply method, the combustion temperature in the reaction furnace is reduced. Conventionally, in the sulfur recovery process, because the flame stability decreases and the sulfur recovery rate decreases.
The sulfur is recovered from the acid gas by the Claus reaction method of the partial supply system. In the partial supply method, as shown in FIG. 3B, a part of the acidic gas is bypassed to the reaction furnace, and the bypassed acid gas is mixed with the reaction furnace outlet gas downstream of the reaction furnace. In this method, the ratio of hydrogen sulfide to sulfur dioxide is 2: 1. Bypassing part of the acid gas
This is to maintain the thermal efficiency of the process. That is, when the concentration of hydrogen sulfide is low, it is necessary to make the reaction temperature as high as the reaction temperature of the non-catalytic Claus reaction in the high-temperature reaction zone in the high-temperature reaction zone. This is because, when the entire amount of the acidic gas is fed into the furnace, the thermal efficiency of the process decreases. Hereinafter, in the same manner as in the whole amount supply method, the non-catalytic Claus reaction in the high-temperature reaction zone and the catalytic Claus reaction in the low-temperature reaction zone respectively generate sulfur, and the generated sulfur is condensed and separated by the condenser. It is a method of collecting.

[0006]

By the way, as natural gas mining progresses with an increase in demand, natural gas is mined not only from good natural gas sources but also from bad natural gas sources. ing. Therefore, the acid gas separated from the natural gas contains, for example, at least about 70% by volume of carbon dioxide as shown in Table 3, and therefore has a low hydrogen sulfide concentration, and furthermore has a hydrocarbon compound, especially a carbon number of 3 or more. It is necessary to treat an acidic gas containing a large amount of a hydrocarbon compound.

[Table 5] If sulfur is to be recovered from such an acidic gas containing a large amount of hydrocarbon compounds by the Claus reaction method, soot is generated due to unburned hydrocarbon compounds in the reaction furnace into which the acidic gas has been introduced, and the subsequent Claus reaction catalyst There was a problem that the layer was clogged by the soot.

Therefore, in order to prevent clogging in the subsequent Claus reaction catalyst layer, it is necessary to raise the flame temperature and air ratio in the reaction furnace to completely burn the hydrocarbon compounds and to prevent the generation of soot. is there. Therefore, when trying to recover sulfur from the above-mentioned low-quality acid gas by the above-mentioned total amount supply method, a temperature of 1300 ° C. or more is set as the flame temperature of the reactor, and the air ratio of the air supplied to the reactor is reduced. 70%
It is necessary to set above. As a result, the optimal conditions for sulfur recovery, ie, H _{2 in the} gas leaving the reactor
It becomes impossible to set the amount of air to be fed into the reactor so that the S / SO ₂ ratio becomes H ₂ S / SO ₂ = 2, and the sulfur recovery rate decreases. Here, the air ratio is a ratio defined by the following equation. Air ratio = A / B A = Actual amount of air supplied (Nm ³ / hr) B = Theoretical air amount (Nm ³ / hr) necessary for complete combustion of acid gas

On the other hand, when attempting to recover sulfur from the above-mentioned low-quality acidic gas by the above-mentioned partial supply method, since the acidic gas is partially bypassed to the reactor, the acidic gas is almost completely removed by the reactor. Although it can be burned,
Hydrocarbon compounds entrained in the acid gas that has been bypassed rapidly lower the activity of the subsequent Claus reaction catalyst layer, and thus shorten the period until catalyst regeneration and increase operating costs. In addition, there is also a problem that the hydrocarbon compound is mixed with the product sulfur to cause coloring.

As described above, if sulfur is to be recovered from a low-quality acid gas by the conventional method, problems such as a reduction in the sulfur recovery rate, a reduction in the activity of the catalyst, and a coloring of the product sulfur occur.
It was difficult to stably recover high-quality sulfur. Therefore, an object of the present invention is to treat acidic gas containing a large amount of carbon dioxide and thus having a low concentration of hydrogen sulfide and a large amount of a hydrocarbon compound, particularly a hydrocarbon compound having a carbon number of 3 or more, to obtain a good quality gas. An object of the present invention is to provide a method for stably recovering sulfur at a high recovery rate.

[0010]

In order to achieve the above object, a method for recovering sulfur from an acid gas according to the present invention comprises hydrogen sulfide, mercaptan other than hydrogen sulfide, COS,
In addition to non-hydrogen sulfide-based sulfur compounds consisting of sulfur compounds such as sulfur dioxide, hydrocarbon compounds, and a method of recovering sulfur from acid gas having carbon dioxide more than the content of hydrogen sulfide and non-hydrogen sulfide-based sulfur compounds Then, air is supplied in an amount necessary to burn a predetermined ratio of hydrogen sulfide in the acid gas and a total amount of hydrocarbon compounds and non-hydrogen sulfide sulfur compounds in the acid gas. Reacting at a temperature of 1350 ° C. or higher while burning the acidic gas while generating a reactive gas containing sulfur and a reducing gas containing sulfur dioxide by a reaction between hydrogen sulfide and carbon dioxide;
Next, a combustion reaction step of separating the generated sulfur, a reaction of the remaining gas from which the sulfur was separated by the Claus reaction, a Claus reaction step of separating the generated sulfur, and, following the Claus reaction step, the remaining sulfur separated A step of introducing gas into the reduction catalyst layer to reduce sulfur dioxide in the gas to hydrogen sulfide, and a step of mixing the gas that has passed through the reduction step with air and directly sending it to the oxidation catalyst layer to generate sulfur And characterized in that:

Preferably, in the combustion reaction step, 5 to 40% by volume of the hydrogen sulfide in the acid gas is combusted with the total amount of the hydrocarbon compound and the non-hydrogen sulfide sulfur compound in the acid gas. The acid gas is burned while supplying the necessary amount of air. The reason is that at a hydrogen sulfide concentration of 25% or more, the sulfur recovery rate can be maintained at a somewhat high level even in a usual full-supply system. The present invention also relates to a method for producing a low-quality acid gas, particularly a sulfide gas, in which the content of a hydrocarbon compound in the acid gas is 2.0% by volume or more and the content of carbon dioxide is 60% by volume or more. Hydrogen concentration is 20% by volume
Optimum for sulfur recovery from the following acid gases: The method of the present invention can be economically applied even when the concentration of hydrogen sulfide is as low as 5 to 10% by volume.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described specifically and in detail. In the method of the present invention, first, the entire amount of the supplied low-quality acid gas is preheated in a combustion furnace,
The combustion reaction step is carried out by feeding the reactor into a reactor in which the reactor temperature is maintained at 1350 ° C. or higher. The combustion furnace is used to burn a predetermined ratio of hydrogen sulfide in the acid gas, for example, 1/3 of the amount of hydrogen sulfide and the total amount of the hydrocarbon compound and the sulfur compound in the acid gas. Supply the required amount of air. In the combustion reaction step, the temperature of the combustion furnace was set to 135.
In order to maintain the temperature at 0 ° C. or higher, an auxiliary fuel such as a fuel gas may be used as a burner fuel of the combustion furnace as needed. Under this condition, hydrogen sulfide is converted into the above-mentioned reaction formulas (1) and (2).
, Sulfur compounds are converted to sulfur dioxide, sulfur and water, the hydrocarbon compounds are entirely burned and converted to carbon dioxide and water, and the sulfur compounds are converted to sulfur dioxide, carbon dioxide and water by an oxidation reaction. Therefore, no soot is generated as in the conventional method, and the activity of the subsequent Claus reaction catalyst is not reduced due to poisoning by the unburned hydrocarbon compound. On the other hand, simultaneously with the progress of the reaction according to the reaction formulas (1) and (2), a part of the large amount of carbon dioxide, which had diluted the acidic gas, reacts with hydrogen sulfide to obtain CO 2 by the following formula (5). ₂ + H ₂ S → H ₂ + CO + SO ₂ (5) Converted to a reducing gas composed of hydrogen, carbon monoxide and sulfur dioxide. The reaction gas and the reducing gas containing sulfur generated in the reaction furnace are introduced into the condenser, where the sulfur is condensed and separated.

In the Claus reaction step, the remaining gas is preheated and sent to a reaction tank having a Claus reaction catalyst layer. In the reaction tank, sulfur is generated by a non-catalytic Claus reaction in a high-temperature reaction zone and then by a catalytic Claus reaction in a low-temperature reaction zone, and the generated sulfur is separated by a condenser. In the reduction step, the remaining gas is preheated to, for example, Co
/ Mo catalyst is fed to a reduction tank having a reduction catalyst layer filled with the catalyst to reduce sulfur dioxide to hydrogen sulfide. The conditions for the reduction step are, for example, a normal pressure, a reaction temperature in the range of 240 to 300 ° C., and a reaction temperature of 2000 to 2000 in the presence of a reduction catalyst composed of a Co / Mo catalyst.
Superficial velocity in the range of 3000 / hr. In the direct oxidation step, air is mixed with the gas that has undergone the reduction step, and is fed to a direct oxidation tank having a direct oxidation catalyst layer filled with, for example, a silica-alumina catalyst, to convert hydrogen sulfide under known direct oxidation conditions. Oxidized to sulfur and recovered. After the generated sulfur is separated by the condenser, the remaining gas discharged from the condenser is sent to a waste gas treatment device or a tail gas treatment device, as necessary, for secondary treatment.

As described above, since all the hydrocarbon compounds are decomposed in the reactor in the combustion reaction step, it is possible to avoid clogging of the Claus reaction catalyst layer by unburned carbon and coloring of product sulfur. Also, emission of hydrocarbon compounds into the atmosphere can be avoided. This improves the sulfur recovery and eliminates the need for a separate reducing gas generation facility.

[0015]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Example of Sulfur Recovery Apparatus for Carrying Out the Method of the Present Invention This embodiment is an example of a sulfur recovery apparatus for carrying out the method of the present invention, and FIG. 1 is a flow sheet showing the configuration of the sulfur recovery apparatus of this embodiment. The sulfur recovery device 40 of the present embodiment (hereinafter, referred to as
As shown in FIG. 1, as shown in FIG. 1, in order to perform a combustion reaction process, a combustion gas 2 is burned with a burner using a fuel as a fuel, and a gas obtained by adding air 3 to an acid gas 1 is converted into a gas 135.
The above-mentioned reaction formulas (1), (2) and (5) in a combustion furnace 4 for heating to a high temperature of 0 ° C. or higher and a high temperature atmosphere of 1350 ° C. or higher.
Is provided with a reaction furnace 5 for allowing the reaction to proceed. The combustion furnace 4 and the reaction furnace 5 are configured as an integrated furnace. continue,
The apparatus 40 comprises a first condenser 7 for cooling the gas 6 discharged from the reactor 5 to condense and separate the sulfur 8 to carry out the Claus reaction step, and a remaining gas discharged from the first condenser 7. A first reheating device 10 for reheating the reactor 9, a Claus reactor 12 having a Claus reaction catalyst layer and performing a Claus reaction of the heated gas 11, and a gas 13 exiting from the Claus reactor 12.
And a second condenser 14 for condensing and separating sulfur 15 by cooling the sulfur. Further, the apparatus 40 includes a second reheating device 17 for reheating the remaining gas 16 exiting from the second condenser 14 in order to perform the reduction step, and a reduction catalyst layer for reducing the heated gas 18. Reduction reactor 19 and reduction reactor 19
And a third condenser 21 for condensing and separating sulfur 22 by cooling the gas 13 discharged from. Further, the apparatus 40 includes a third reheating device 24 for reheating the remaining gas 23 exiting from the third condenser 21 and an oxidation catalyst layer to perform the direct oxidation step. Gas 3 with air 30
It comprises a direct oxidation reactor 32 for directly oxidizing 1 and a final condenser 34 for cooling gas 33 discharged from the direct oxidation reactor 32 to condense and separate sulfur 35.

Further, the apparatus 40 includes the combustion furnace 4 and the first,
An air supply system and a fuel gas supply system for supplying air and fuel gas to the second and third reheating devices 10, 17 and 24, respectively, and first, second, third and final condensers 7, 14, Ancillary devices such as a boiler water supply system for supplying boiler water (BFW) as cooling water are provided at 21 and 34. First, second, third and final condensers 7, 1
Nos. 4, 21, and 34 are for evaporating BFW by the latent heat of the generated sulfur vapor to produce steam, thereby condensing the generated sulfur vapor and taking it out of the system.
The first, second and third reheating devices 10, 17 and 24
The gas whose temperature has been reduced is heated by a condenser and then heated again to a temperature required for the progress of the reaction. Usually, a line burner is used. The Claus reactor 12 is a reactor provided with a catalyst layer using a sulfur-producing catalyst, for example, an Al ₂ O ₃ or TiO ₂ carrier as a catalyst, in which the above-mentioned reaction formulas (2) to (4) respectively proceed. In the present embodiment, the reduction tank 19 is a type 124 of a KETJENFINE 124 series hydrogen treatment catalyst manufactured by KETJEN.
-3P is used. The direct oxidation tank 32 uses a silica-alumina catalyst (Super Claus catalyst manufactured by Comprimo) as an oxidation catalyst.

Embodiment of the Method of the Present Invention This embodiment is an example of implementing the method of the present invention using the above-described apparatus 40. The method of the present embodiment will be described below. First, the acidic gas 1 is fed into the combustion furnace 4 and then into the reaction furnace 5 to perform a combustion reaction step. At this time, the acid gas 1 is mixed with 1/3 of the amount of hydrogen sulfide in the acid gas 1 and air 3 in an amount necessary to burn the entire amount of the hydrocarbon compound and the sulfur compound in the acid gas 1. In the combustion furnace 4 and the reaction furnace 5, the reactions of the above-mentioned reaction formulas (1) and (2) progress, a part of the hydrogen sulfide is oxidized to sulfur dioxide, and the hydrogen sulfide reacts with the sulfur dioxide to form sulfur. Is generated. In addition, all of the hydrocarbon compounds are burned and converted to carbon dioxide and water, and the sulfur compounds are converted to sulfur dioxide, carbon dioxide and water by an oxidation reaction. Therefore, no soot is generated as in the conventional method, and the activity of the subsequent Claus reaction catalyst is not reduced due to poisoning by the unburned hydrocarbon compound. On the other hand, simultaneously with the progress of the reaction according to the reaction formulas (1) and (2), a part of a large amount of carbon dioxide is
It reacts with hydrogen sulfide and is converted into a reducing gas composed of CO ₂ + H ₂ S → H ₂ + CO + SO ₂ hydrogen, carbon monoxide and sulfur dioxide according to the following equation (5). Next, the sulfur vapor generated in the combustion reaction step is condensed in the first condenser 7 and taken out of the system as product sulfur 8.

Next, the process proceeds to the Claus reaction step. In the Claus reaction step, the remaining acidic gas 9 is heated by the first reheating device 10 and flows into the first Claus reactor 12, where the reactions of the reaction formulas (2) to (4) are advanced to remove sulfur. Generate. The generated sulfur vapor is condensed by the second condenser 14 and taken out of the system as product sulfur 15.

Subsequently, the process proceeds to a reduction step. In the reduction step, the remaining acidic gas 16 having passed through the Claus reaction step is converted into a second gas.
It is heated by the reheating device 17, flows into the reduction tank 19, and reduces sulfur dioxide to hydrogen sulfide or sulfur. The generated sulfur vapor is condensed by the third condenser 21 and taken out of the system as product sulfur 22.

Subsequently, the process proceeds to a direct oxidation step. In the direct oxidation step, the remaining acidic gas 23 after the reduction step is converted into the second gas.
Heat is performed by the reheating device 24. Next, the air 30 is mixed with the heated gas and directly flows into the oxidation tank 32 to oxidize hydrogen sulfide to generate sulfur. The generated sulfur vapor is
It is condensed by the condenser 34 and taken out of the system as product sulfur 35. The tail gas 36 coming out of the third condenser 34 includes:
Since almost no hydrogen sulfide is contained, it is released from the tail gas treatment device (not shown) to the atmosphere.

Example of Experiment by Example Method Using a device having the same configuration as the device 40 shown in FIG. 1, a simulation operation was performed according to the example method, and the results shown in Tables 1 and 2 were obtained. As shown in Table 1, the acid gas used as the source gas in the simulation calculation is as follows.
It contains 81.6% by volume of carbon dioxide, 9.0% by volume of hydrogen sulfide and 4.4% by volume of hydrocarbon compounds.
According to the method of this example, the sulfur recovery was 92.4%.

[Table 1]

[Table 2] Note that the stream numbers in Table 1 and the following Table 2 correspond to the stream numbers shown in FIGS. 1 and 2, respectively.

Comparative Example Using Conventional Total Supply Method As a comparative example to the method of the present invention, a simulation calculation for recovering sulfur from the same acidic gas as in the above experimental example was performed by the conventional sulfur recovery method using the full supply method. And the results shown in Table 4 were obtained.

[Table 3]

[Table 4]

In this comparative example, a sulfur recovery apparatus 50 as shown in FIG. 2 was configured as an apparatus for performing the conventional sulfur recovery method using the full amount supply method. Sulfur recovery device 5 of comparative example
0 is the reduction tank 19 of the apparatus 40 of FIG. 1 as shown in FIG.
1 except that a second Claus reaction tank 52 is provided. Also,
The operating conditions of the device 50 are such that in the combustion furnace 4 and the reaction furnace 5, hydrogen sulfide and sulfur dioxide in the gas exiting the reaction furnace 5 are burned by introducing air so that the volume ratio becomes 2: 1, Second
The Claus reaction tank 52 is the same as the experiment example except that the Claus reaction proceeds. According to the comparative example method, the sulfur recovery was 89.3%.

[0024]

According to the method of the present invention, the amount of hydrogen sulfide in a predetermined ratio of the hydrogen sulfide in the acid gas and the total amount of the hydrocarbon compound and the sulfur compound in the acid gas are burned. The acid gas is burned at a temperature of 1350 ° C. or more while supplying air to generate a reaction gas containing sulfur and a reducing gas containing sulfur dioxide from a reaction between hydrogen sulfide and carbon dioxide, and a reduction reaction in the latter stage To reduce the reducing gas to recover sulfur. This makes it possible to remove high-quality sulfur from an acidic gas containing carbon dioxide of 70% by volume or more, that is, an acid gas having a hydrogen sulfide concentration of 30% by volume or less and containing a large amount of a hydrocarbon compound. It can be recovered stably at a high recovery rate. Further, hydrocarbon compounds and sulfur compounds contained in the acid gas are not discharged to the atmosphere without burning. Further, the activity of the Claus reaction catalyst layer in the subsequent low-temperature reaction zone is not reduced or clogged.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a configuration of a sulfur recovery apparatus for performing a sulfur recovery method according to the present invention.

FIG. 2 is a flow sheet showing a configuration of a sulfur recovery apparatus that implements a conventional full-supply-type sulfur recovery method.

FIGS. 3 (a) and 3 (b) are block diagrams showing the configuration of a conventional sulfur recovery apparatus that implements a conventional full-supply and partial-supply sulfur recovery method, respectively.

[Explanation of symbols]

40 An example of a sulfur recovery apparatus for performing the sulfur recovery method according to the present invention 4 Combustion furnace 5 Reactor 7 First condenser 10 First reheater 12 First reactor 14 Second condenser 17 Second reheater 19 Reduction reactor 21 Third condenser 24 Third reheating device 32 Direct oxidation reactor 34 Final condenser 50 Sulfur recovery device that implements the conventional full-supply-type sulfur recovery method 52 Second Claus reaction tank

Claims (4)

[Claims] 1. In addition to hydrogen sulfide and non-hydrogen sulfide sulfur compounds other than hydrogen sulfide, such as mercaptan, COS, and sulfur dioxide, hydrocarbon compounds, hydrogen sulfide and non-hydrogen sulfide sulfur A method for recovering sulfur from an acidic gas having carbon dioxide that is more than the content of a compound, comprising a predetermined ratio of hydrogen sulfide in the acidic gas, a hydrocarbon compound and a non-hydrogen sulfide in the acidic gas The reaction between sulfur-containing reaction gas, hydrogen sulfide and carbon dioxide is carried out at a temperature of 1350 ° C. or more while burning the acidic gas while supplying air in an amount necessary to burn all the sulfur compounds. And a combustion reaction step of separating the generated sulfur, and the remaining gas from which the sulfur has been separated is reacted by the Claus reaction to produce a reducing gas containing sulfur dioxide. A Claus reaction step of separating the separated sulfur; a reduction step of sending the remaining gas from which the sulfur has been separated to the reduction catalyst layer to reduce the sulfur dioxide in the gas to hydrogen sulfide, following the Claus reaction step; Mixing air with the gas that has passed through and sending the mixture directly to the oxidation catalyst layer to generate sulfur. 2. In the combustion reaction step, 5 to 40% by volume of hydrogen sulfide of the hydrogen sulfide in the acid gas and the total amount of the hydrocarbon compound and the non-hydrogen sulfide sulfur compound in the acid gas are burned. The sulfur recovery method according to claim 1, wherein the acidic gas is burned while supplying a necessary amount of air. 3. The reduction catalyst step is carried out under the conditions of normal pressure, a reaction temperature in the range of 240 to 300 ° C., and a superficial velocity in the range of 2000 to 3000 / hr under a reduction catalyst comprising a Co / Mo catalyst. The method for recovering sulfur according to claim 1 or 2, wherein: 4. The acidic gas has a hydrocarbon compound content of 2.0% by volume or more and a carbon dioxide content of 6% by volume or more.
The method for recovering sulfur according to any one of claims 1 to 3, wherein the amount is 0% by volume or more.