JPWO2018207726A1 - Hydrogen sulfide removal apparatus and hydrogen sulfide removal method - Google Patents

Abstract

A hydrogen sulfide removing section 30 for removing a hydrogen sulfide by bringing a first raw material containing a hydrocarbon and hydrogen sulfide into contact with an oil-soluble hydrogen sulfide absorbent, and containing a high-boiling hydrocarbon having a boiling point equal to or higher than the boiling point of propane A mixing section 40 for mixing a second raw material to be mixed with a hydrogen sulfide absorbent having the hydrogen sulfide absorbed in the hydrogen sulfide absorbent. It is preferable that a first separation unit 20 that separates the high-boiling-point hydrocarbon from the first raw material is further provided upstream of the hydrogen sulfide removal unit 30.

Description

The present invention relates to a hydrogen sulfide removing device and a hydrogen sulfide removing method.
This application claims priority based on Japanese Patent Application No. 2017-095944 for which it applied to Japan on May 12, 2017, and uses the content here.

  Oil-associated gas and natural gas produced during oil production include water, nitrogen gas, carbon dioxide, hydrogen sulfide, etc. along with methane and other hydrocarbons, which are the main components. ) Are included. Among them, hydrogen sulfide causes toxicity and odor, and also causes corrosion of pipelines. Therefore, it is required that the concentration be as low as possible (for example, less than 20 ppm).

  As a method of removing hydrogen sulfide contained in natural gas, a method of adsorbing and removing hydrogen sulfide by an adsorbent and a method of absorbing and removing hydrogen sulfide by a liquid absorbent are known. Examples of the adsorbent include iron oxide and zinc oxide, and examples of the absorbent include an amine-based solution and a dialdehyde having aldehyde groups at both ends of a long-chain alkane as disclosed in Patent Document 1. Among these, the amine absorption method of absorbing hydrogen sulfide into an amine-based solution has been widely adopted because carbon dioxide can be simultaneously removed.

WO 2015/141535

However, the method for removing hydrogen sulfide using an adsorbent such as iron oxide generates a large amount of waste and has a large environmental load.
In addition, the amine absorption method requires a regeneration step of heating and regenerating an absorbing solution that has absorbed carbon dioxide and hydrogen sulfide, and a process of separating and removing hydrogen sulfide generated in the regeneration step. For this reason, the scale of the plant becomes large, and it is not profitable in terms of processing costs and the like.
In Patent Document 1, no consideration is given to the treatment of an absorbent (also referred to as an absorbent) that has absorbed hydrogen sulfide.
For this reason, in the conventional technology, the treatment of the absorbed agent or the like is complicated, and hydrogen sulfide cannot be efficiently removed.

  Therefore, an object of the present invention is to provide a hydrogen sulfide removing apparatus and a hydrogen sulfide removing method capable of efficiently removing hydrogen sulfide contained in natural gas and the like.

The present invention has the following aspects.
[1] A hydrogen sulfide removing section for removing a hydrogen sulfide by bringing a first raw material containing a hydrocarbon and hydrogen sulfide into contact with an oil-soluble hydrogen sulfide absorbent, and a high-boiling carbon having a boiling point equal to or higher than that of propane. A hydrogen sulfide removing device, comprising: a mixing unit that mixes a second raw material containing hydrogen and a hydrogen sulfide absorbent that has the hydrogen sulfide absorbed into the hydrogen sulfide absorbent.
[2] The hydrogen sulfide removing device according to [1], further including a first separation unit that separates the high-boiling hydrocarbon from the first raw material before the hydrogen sulfide removing unit. .
[3] A second separation unit for separating the high-boiling-point hydrocarbon from the first raw material treated in the hydrogen sulfide removal unit is further provided downstream of the hydrogen sulfide removal unit, [1]. Or the hydrogen sulfide removing device according to [2].
[4] The apparatus further comprises an introduction section for introducing a mixture of the high-boiling-point hydrocarbon and the hydrogen sulfide absorbent obtained in the first separation section into the hydrogen sulfide removal section, [2] The hydrogen sulfide removing device according to 1.

Further, the present invention has the following aspects.
[5] A hydrogen sulfide removing step of removing the hydrogen sulfide by bringing a first raw material containing a hydrocarbon and hydrogen sulfide into contact with an oil-soluble hydrogen sulfide absorbent, and a high-boiling carbon having a boiling point equal to or higher than that of propane. A mixing step of mixing a hydrogen-containing second raw material and a hydrogen sulfide absorbent having the hydrogen sulfide absorbed in the hydrogen sulfide absorbent, and removing the hydrogen sulfide from the first raw material A method for removing hydrogen sulfide.
[6] The method for removing hydrogen sulfide according to [5], further comprising a first separation step of separating the high-boiling hydrocarbon from the first raw material before the hydrogen sulfide removing step. .
[7] The method according to [5], further comprising, after the hydrogen sulfide removing step, a second separating step of separating the high-boiling hydrocarbon from the first raw material treated in the hydrogen sulfide removing step. Or the method for removing hydrogen sulfide according to [6].
[8] A premixing step of mixing the high-boiling-point hydrocarbon obtained in the first separation step with the hydrogen sulfide absorbent, wherein the hydrogen sulfide removing step includes mixing the first raw material with the premixed hydrogen. The method for removing hydrogen sulfide according to [6], wherein the method comprises bringing the mixture obtained in the step into contact with the mixture.
[9] In the mixing step, the second raw material and the hydrogen sulfide-absorbing agent are mixed under the condition that the high-boiling-point hydrocarbon is in a pressurized and liquefied state, [5] to [5]. 8] The method for removing hydrogen sulfide according to any one of [1] to [8].
[10] The method for removing hydrogen sulfide according to any of [5] to [8], wherein the high-boiling hydrocarbon is a liquid at room temperature.

  ADVANTAGE OF THE INVENTION According to the hydrogen sulfide removal apparatus and the hydrogen sulfide removal method of this invention, hydrogen sulfide contained in natural gas etc. can be removed efficiently.

It is a system diagram showing composition of a hydrogen sulfide removal device concerning a first embodiment of the present invention. It is a system diagram showing composition of a hydrogen sulfide removal device concerning a second embodiment of the present invention. It is a system diagram showing composition of a hydrogen sulfide removal device concerning a third embodiment of the present invention.

The hydrogen sulfide removing device of the present invention includes a hydrogen sulfide removing unit and a mixing unit.
The hydrogen sulfide removing device of the present invention can be applied, for example, as a hydrocarbon refining device (a device for producing a purified hydrocarbon). In particular, it is suitable as an LNG (Liquid Natural Gas) liquefied natural gas (LNG) production apparatus.
The hydrogen sulfide removing method of the present invention has a hydrogen sulfide removing step and a mixing step.
The hydrogen sulfide removal method of the present invention can be applied, for example, as a hydrocarbon purification method (a method of producing a purified hydrocarbon). In particular, it is suitable as an LNG manufacturing method.

[First embodiment]
Hereinafter, a hydrogen sulfide removing device according to a first embodiment of the present invention and a hydrogen sulfide removing method using the device will be described in detail with reference to the drawings.
The hydrogen sulfide removing device of the present invention is a device that removes hydrogen sulfide from a first raw material containing a hydrocarbon (alkane) and hydrogen sulfide, and takes out purified hydrocarbon as a target gas.
In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios and the like of the respective components are not necessarily the same as the actual ones. Absent.

<Hydrogen sulfide removal device>
FIG. 1 is a system diagram showing a configuration of the hydrogen sulfide removing device according to the first embodiment of the present invention. As shown in FIG. 1, the hydrogen sulfide removing apparatus 1 includes a separator 12, a first separating unit 20, a hydrogen sulfide removing unit 30, a mixing unit 40, an absorbent supply source 50, an LPG (Liquidified Petroleum Gas). , Liquefied petroleum gas) tank 60, and pipes L1 to L8.

A separator 12 is provided downstream of the raw material supply source 10, and the raw material supply source 10 and the separator 12 are connected by a pipe L1.
A first separation unit 20 is provided downstream of the separator 12, and the separator 12 and the first separation unit 20 are connected by a pipe L1.
A hydrogen sulfide removing unit 30 and a mixing unit 40 are provided downstream of the first separating unit 20. The first separating section 20 and the hydrogen sulfide removing section 30 are connected by a pipe L2. The first separation section 20 and the mixing section 40 are connected by a pipe L3. The pipe L3 is provided with a compressor 90. A pipe L5 is connected to the hydrogen sulfide removing unit 30. A mixing section 40 is provided downstream of the hydrogen sulfide removing section 30, and the hydrogen sulfide removing section 30 and the mixing section 40 are connected by a pipe L4. The pipe L4 is provided with a branch 101 and a pump 71.
An LPG tank 60 is provided downstream of the mixing section 40, and the mixing section 40 and the LPG tank 60 are connected by a pipe L8. The pipe L <b> 6 branches from the branch 101 and is connected to the introduction section 80 provided in the hydrogen sulfide removing section 30. The pipe L6 is provided with a pump 70 and a branch 102. The pipe L7 branches off from the branch 102 and is connected to the absorbent supply source 50.

(Raw material supply source)
The raw material supply source 10 is a supply source (supply unit) that supplies the first raw material containing hydrocarbons and hydrogen sulfide to the hydrogen sulfide removing device 1.
The first raw material may contain hydrocarbons and hydrogen sulfide, for example, mined natural gas, liquefied petroleum gas obtained when refining petroleum, and gas associated with oil fields produced with oil production. And coal bed methane (CBM) that can be collected from a coal seam, and coke oven gas obtained when coal is carbonized in a coke oven. The first raw material may contain gases such as carbon dioxide, nitrogen, and helium in addition to hydrocarbons and hydrogen sulfide.
The first raw material may be a gas or a liquid, a mixture of a gas and a liquid, or a mixture of a gas, a liquid, and a solid.

  The raw material supply source 10 only needs to be able to supply the first raw material, and it is necessary to supply the ground equipment of the oil and gas field, a pipeline connected thereto, a tank capable of temporarily storing the first raw material, and a movable tank. Loading vehicles and the like. Further, the raw material supply source 10 is applicable to an LNG plant, a biogas plant, and the like.

  Examples of the pipe L1 include metal or resin pipes, but are not limited to these pipes. Further, the material of the pipe L1 may be the same as the material of the other pipe L2 or the like, or may be different. Hereinafter, the same applies to the types and materials of piping in this specification.

(Separator)
The separator 12 is a device that removes moisture, sludge, and the like contained in the first raw material.
As the separator 12, a known device that removes moisture, sludge, and the like from natural gas, crude oil, and the like may be used. Examples of the separator 12 include a device that removes moisture, sludge, and the like in the first raw material using a coalescer or a hydrophilic filter made of lipophilic fiber or the like.
In the present embodiment, hydrocarbons having 5 or more carbon atoms are removed as sludge or the like by the separator 12, and hydrocarbons having 4 or less carbon atoms (methane, ethane, propane, butane) are supplied to the first separation section 20. Etc. are supplied.

(First separation unit)
The first separation unit 20 is a device that separates a high-boiling hydrocarbon having a boiling point equal to or higher than the boiling point of propane (hereinafter, also simply referred to as “high-boiling hydrocarbon”) from the first raw material. Here, the “propane boiling point” is −42 ° C. The high-boiling hydrocarbons are propane and hydrocarbons (alkanes) having 4 or more carbon atoms. The separator 12 is provided as described above, and the hydrocarbons (alkanes) having 5 or more carbon atoms are substantially removed. Is preferred. That is, the high boiling point hydrocarbon is preferably mainly composed of propane or butane, or both.
In the first separation section 20, a second raw material containing a high-boiling hydrocarbon is separated from the first raw material.
In the present embodiment, the first separation unit 20 separates a second raw material containing a high-boiling hydrocarbon (propane, butane, or the like) from the first raw material.

In the first separation section 20, a separation membrane capable of separating hydrocarbons according to the difference in molecular weight and size of hydrocarbons is used.
In the present embodiment, the separation membrane refers to a gas-permeable permeable member having a structure with a difference in transmittance depending on the type of gas due to fine through holes and the like. Examples of the mechanism include a mechanism for controlling the transmittance based on the relationship between the size of the through hole and the molecule, and a mechanism using the mean free path based on the molecular weight of the gas. Based on various mechanisms, there are various materials such as ceramics such as zeolite, polyimides, and organic compounds such as cellulose, silicone, and fluorine-based polymers. Examples of the form of the separation device using the separation membrane include a form provided as various separation membrane modules such as a cylindrical, hollow fiber, flat plate, or bag-shaped separation membrane wound into a cylindrical shape. These separation membranes can be selected according to the price of natural gas as the first raw material, the price of hydrocarbon gas such as methane as the product gas, and the like.

  The first separation unit 20 is not limited to a separation device using a separation membrane as long as it can separate the second raw material from the first raw material, and a known device for separating hydrocarbons is used. Is also good. Examples of the first separation unit 20 include a normal-pressure distillation apparatus such as a slag catcher, a topper, and a naphtha splitter.

(Hydrogen sulfide removal section)
The hydrogen sulfide removing unit 30 is a device that removes hydrogen sulfide by bringing the first raw material into contact with an oil-soluble hydrogen sulfide absorbent (hereinafter, also simply referred to as “absorbent”).
The hydrogen sulfide removing unit 30 is formed of, for example, a reactor such as an absorption tower, and an introduction unit 80 for supplying an absorbent is provided inside the absorption tower.
The hydrogen sulfide removing unit 30 is a device that sprays the absorbent into the interior of the absorption tower from the introduction unit 80 and makes the absorbent come into contact with the first raw material.
The hydrogen sulfide removing unit 30 is not limited to the device that sprays the absorbent, and may be a device that removes hydrogen sulfide by bubbling the first raw material into a liquid in which the absorbent is stored at the bottom of the absorption tower.

Examples of the oil-soluble hydrogen sulfide absorbent include a dialdehyde having an aldehyde group near both ends of a long-chain alkane skeleton. Examples of the dialdehyde include 1,9-nonanedial having low toxicity, excellent heat resistance, and storage stability, and 2-methyl-1,8-octanedial (2- methyl-1,8-octanedial) and the like.
The absorbent is preferably used in the form of a solution. For example, as the absorbent, kerosene, naphtha, low molecular weight polyethylene glycol (molecular weight: 200 to 1000) of 1,9-nonandial, 2-methyl-1,8-octanedial, etc. is 2 to 10 times (by volume). A solvent dissolved in a solvent such as the above is preferably used. Here, kerosene means a fraction having a flash point of 40 ° C. or higher and a 95% by volume distillation temperature of 300 ° C. or lower. The flash point refers to a value measured according to JIS K2265. Naphtha is a fraction having a 10% by volume distillation temperature of 50 ° C. or more and a 90% by volume distillation temperature of 150 ° C. or less, and a fraction containing a fraction having a boiling point range of 30 to 150 ° C. means.
In the present specification, the term “oil-soluble” refers to a compound which does not phase-separate by mixing a compound and kerosene in the range of 2: 8 to 8: 2 with kerosene No. 1 specified in JIS K2203: 2009. It has the property to have.

(Mixing section)
The mixing section 40 is a device that mixes the second raw material containing a high-boiling hydrocarbon with the hydrogen sulfide-absorbed agent.
Examples of the mixing unit 40 include a batch type mixing device and an in-line type mixing device.

(Absorbent supply source)
The absorbent supply source 50 is a supply source that supplies the hydrogen sulfide absorbent to the hydrogen sulfide removing unit 30.
The absorbent supply source 50 only needs to be able to supply the absorbent, and examples thereof include an installed tank capable of temporarily storing the absorbent, a movable tank-mounted vehicle, and the like.

(LPG tank)
The LPG tank 60 is a tank for temporarily storing a mixture of the absorbent and the second raw material.
The LPG tank 60 only needs to be able to temporarily store the mixture of the absorbed agent and the second raw material, and examples thereof include an equipped tank capable of temporarily storing the mixture, and a movable tank loaded vehicle.

<Hydrogen sulfide removal method>
Next, a method for removing hydrogen sulfide from the first raw material using the hydrogen sulfide removing device 1 will be described.
This embodiment includes a hydrogen sulfide removing step and a mixing step, and further includes a first separation step of separating a high-boiling-point hydrocarbon from the first raw material before the hydrogen sulfide removing step.

The first raw material containing hydrocarbons and hydrogen sulfide is supplied from the raw material supply source 10 to the separator 12 via the pipe L1.
The hydrocarbon in the first raw material contains methane, ethane, and high-boiling hydrocarbons having a boiling point equal to or higher than that of propane, such as propane and butane.
The first raw material contains water, sludge, and the like in addition to hydrocarbons and hydrogen sulfide.
If moisture, sludge, or the like is contained in the first raw material, a high-purity target gas or high-quality LPG cannot be obtained. Therefore, it is preferable to remove impurities such as moisture and sludge in the first raw material.
By removing moisture, sludge, and the like in the first raw material, a high-purity target gas and high-quality LPG can be obtained.

The first raw material processed by the separator 12 is supplied with water, sludge, etc., to the first separation unit 20 via the pipe L1.
In the first separation section 20, a second raw material containing a high-boiling hydrocarbon is separated from the first raw material (first separation step).
In this embodiment, the high-boiling hydrocarbons are propane and butane, which are separated as gases at room temperature.
In this specification, room temperature means 1 to 30 ° C.

The first raw material processed in the first separation unit 20 is supplied to the hydrogen sulfide removal unit 30 via the pipe L2. The high-boiling hydrocarbon is removed from the first raw material supplied to the hydrogen sulfide removing unit 30. Therefore, hydrocarbons (alkanes) in the first raw material supplied to the hydrogen sulfide removing unit 30 are methane and ethane.
The separated second raw material is supplied to the mixing section 40 via the pipe L3.
In the present embodiment, since the high-boiling hydrocarbon is separated as a gas at room temperature, the high-boiling hydrocarbon is compressed by the compressor 90, moves as a liquid (LPG) at room temperature in the pipe L3, and is mixed. Is supplied to the section 40.

The absorbent is supplied from the absorbent supply source 50 to the introduction section 80 via the pipe L7, the branch 102, and the pipe L6. The absorbent supplied to the introduction section 80 is sprayed in an absorption tower in the hydrogen sulfide removing section 30, and an absorbing operation for absorbing hydrogen sulfide is performed (hydrogen sulfide removing step). The sprayed absorbent absorbs hydrogen sulfide and is collected at the bottom of the absorption tower as a hydrogen sulfide absorbent (hereinafter also simply referred to as “absorbed”), and a part thereof is pressurized by the pump 70 from the branch 101, Circulate through the pipe L6.
In the hydrogen sulfide removing section 30, the first raw material is brought into contact with the mixture of the absorbent and the absorbent so that the hydrogen sulfide in the first raw material is transferred to the absorbent in the mixture.
The hydrogen sulfide-absorbed agent in which hydrogen sulfide has been absorbed by the absorbent is pressurized by the pump 71 in the pipe L4, and then supplied to the mixing unit 40 through the pipe L4.

In the hydrogen sulfide removing section 30, the first raw material from which hydrogen sulfide has been removed is sent to the pipe L5 as a target gas. The target gas is separated into an inert gas such as nitrogen and helium and an LNG such as methane and ethane and shipped as a product in an LNG manufacturing process or the like as necessary.
The temperature in the hydrogen sulfide removing section 30 in the hydrogen sulfide removing step is preferably −30 to 150 ° C., and more preferably 0 to 130 ° C. The pressure in the hydrogen sulfide removing section 30 in the hydrogen sulfide removing step is preferably -0.1 to 10 MPa, more preferably 0 to 1.0 MPa.
The concentration of hydrogen sulfide in the target gas is preferably 100 ppm (by volume) or less, more preferably 30 ppm or less, still more preferably 10 ppm or less, and particularly preferably 4 ppm or less. When the concentration of hydrogen sulfide in the target gas is 100 ppm or less, there is an advantage that the influence on the sense of smell can be suppressed even when the target gas is leaked due to a leak accident or the like. In addition, there is an advantage that the influence on airway irritation and conjunctivitis can be suppressed, and when it is 4 ppm or less, there is an advantage that it can be shipped as a raw material gas for a gas pipeline in addition to the above advantages.
The hydrogen sulfide-containing concentration is most preferably 0 ppm, but if it is less than the above upper limit, the above-mentioned advantages can be secured. There may be.

In the mixing section 40, the second raw material supplied through the pipe L3 and the absorbed agent supplied through the pipe L4 are mixed (mixing step). Since the absorbent is oil-soluble, the absorbent that has absorbed hydrogen sulfide is also oil-soluble. For this reason, the absorbent and the high boiling point hydrocarbon in the second raw material have compatibility, and the absorbent and the second raw material can be mixed. At this time, both the absorbing agent and the second raw material are supplied to the mixing unit 40 in a liquid state, so that the compatibility between the two is further improved.
Therefore, in the mixing section 40, it is preferable that the second raw material and the absorbent are mixed under the condition that the high-boiling hydrocarbon is in a pressurized and liquefied state. Further, in the mixing section 40, it is preferable that the high-boiling hydrocarbon is liquid at room temperature. The mixing section 40 may include a stirrer for better mixing the second raw material and the absorbent.
In the mixing section 40, the absorbent mixed with the second raw material is an impurity of the second raw material. For this reason, the mass of the absorbent mixed with the second raw material is preferably 10% by mass or less, more preferably 1% by mass or less with respect to 100% by mass of the second raw material, and the existing LPG equipment is used. In this case, the content is more preferably 0.1% by mass or less.
If kerosene or naphtha is used as the solvent of the absorbent, the vapor pressure of the second raw material may be reduced by setting the solvent of the absorbent to 100% by mass or more with respect to 100% by mass of the second raw material. it can. When the vapor pressure of the second raw material is reduced, the compressor 90, the pipe L3, the pipe L8, the LPG tank 60, and the like can be simplified. For this reason, the mass of the solvent of the absorbing agent is preferably 100% by mass or more based on 100% by mass of the second raw material.

The mixture of the absorbent and the second raw material mixed in the mixing section 40 is supplied to the LPG tank 60 via the pipe L8.
In the present embodiment, since hydrocarbons having 5 or more carbon atoms are removed from the first raw material by the separator 12, the high-boiling hydrocarbon in the second raw material is propane or butane, or both. Therefore, the mixture of the absorbent and the second raw material mixed in the mixing section 40 is supplied to the mixing section 40 as LPG whose main component is propane, butane, or the like.
Since the absorbent containing hydrogen sulfide is diluted with a large amount of LPG, the concentration of hydrogen sulfide in the mixture of the absorbent and the second raw material can be reduced. The concentration of hydrogen sulfide in the mixture of the absorbent and the second raw material is preferably 50 to 100 ppm by mass, and more preferably 50 to 70 ppm by mass. If the concentration of hydrogen sulfide in the mixture of the absorbent and the second raw material is 100 ppm by mass or less, the product is shipped as an LPG product without going through the process of removing hydrogen sulfide again to comply with LPG shipping standards. It becomes possible. When the concentration of hydrogen sulfide in the mixture of the absorbent and the second raw material is 50 ppm by mass or more, the effect of the present invention can be more easily obtained.

After the mixture of the absorbent and the second raw material is temporarily stored in the LPG tank 60, it can be carried out to the outside by means such as a tank lorry.
The mixture of the discharged absorbent and the second raw material may be mixed with a separately produced crude oil and processed in a hydrodesulfurization facility of an existing petroleum refining facility. Hydrogen sulfide absorbed by the absorbent is separated in the hydrodesulfurization facility, and can be commercialized as single sulfur in a sulfur recovery device of another facility.

  In the present embodiment, the concentration of hydrogen sulfide in the target gas can be reduced, so the hydrogen sulfide removing device of the present embodiment is suitable as an LNG manufacturing device.

[Second embodiment]
Next, a hydrogen sulfide removing device according to a second embodiment of the present invention and a hydrogen sulfide removing method using the device will be described. Hereinafter, FIG. 2 will be described focusing on portions different from the first embodiment described above. FIG. 2 is a system diagram showing a configuration of the hydrogen sulfide removing device according to the second embodiment of the present invention. As shown in FIG. 2, the hydrogen sulfide removing device 2 includes a separator 12, a heavy metal removing unit 14, a first hydrogen sulfide removing unit 32, a second hydrogen sulfide removing unit 34, an absorbent supply source 52, , A second separating section 22, a mixing section 42, an LPG tank 60, pipes L1 ′ to L8 ′, and pipes L9 to L11.

A separator 12 is provided downstream of the raw material supply source 10, and the raw material supply source 10 and the separator 12 are connected by a pipe L1 '.
The heavy metal removing unit 14 is provided at the subsequent stage of the separator 12, and the separator 12 and the heavy metal removing unit 14 are connected by a pipe L1 '. A first hydrogen sulfide removing unit 32 is provided downstream of the heavy metal removing unit 14, and the heavy metal removing unit 14 and the first hydrogen sulfide removing unit 32 are connected by a pipe L1 '.
A second hydrogen sulfide removing unit 34 and a mixing unit 42 are provided downstream of the first hydrogen sulfide removing unit 32. The first hydrogen sulfide removing unit 32 and the second hydrogen sulfide removing unit 34 are connected by a pipe L2 '. The first hydrogen sulfide removing section 32 and the mixing section 42 are connected by a pipe L3 '. A pump 74 is provided in the pipe L3 '.
The second separation unit 22 is provided downstream of the second hydrogen sulfide removal unit 34, and the second hydrogen sulfide removal unit 34 and the second separation unit 22 are connected by a pipe L5 '. A mixing section 42 is provided downstream of the second separation section 22, and the second separation section 22 and the mixing section 42 are connected by a pipe L10. The pipe L10 is provided with a compressor 92. The pipe L11 is connected to the second separation section 22.
The pipe L9 branches from the branch 103 provided in the pipe L3 'and is connected to the introduction section 82 provided in the first hydrogen sulfide removing section 32. The pipe L9 is provided with a pump 72 and a branch 104.
The pipe L4 ′ branches from the branch 104 of the pipe L9 and is connected to the second hydrogen sulfide removing unit. A branch 105 is provided in the pipe L4 '.
The pipe L6 ′ branches from the branch 105 of the pipe L4 ′ and is connected to an introduction section 84 provided in the second hydrogen sulfide removing section. The pipe L6 ′ is provided with a pump 73 and a branch.
The pipe L7 'branches from the branch 106 of the pipe L6', and is connected to the absorbent supply source 52.
An LPG tank 60 is provided downstream of the mixing section 42, and the mixing section 42 and the LPG tank 60 are connected by a pipe L8 '.

(Heavy metal removal section)
The heavy metal removing unit 14 is a device for removing heavy metal components such as mercury vapor from the first raw material.
The heavy metal removing unit 14 is not particularly limited, and a known device that removes heavy metals can be used. Examples of the heavy metal removing unit 14 include an adsorbent in which silica gel or alumina supports a metal sulfide, and a mercury removal device in which activated carbon is filled with an adsorbent in which a metal sulfide is supported.

(First hydrogen sulfide removal unit)
The first hydrogen sulfide removing unit 32 is a device that removes hydrogen sulfide by bringing the first raw material into contact with an oil-soluble hydrogen sulfide absorbent similarly to the hydrogen sulfide removing unit 30 in the above-described first embodiment. .

(Second hydrogen sulfide removal unit)
The second hydrogen sulfide removing unit 34 is a device that removes hydrogen sulfide by bringing the first raw material into contact with an oil-soluble hydrogen sulfide absorbent, similarly to the hydrogen sulfide removing unit 30 in the above-described first embodiment. .

In the present embodiment, the first separation unit 20 in the first embodiment described above is not provided in a stage preceding the first hydrogen sulfide removing unit 32. Therefore, the first raw material supplied to the first hydrogen sulfide removing unit 32 contains a high-boiling hydrocarbon. In the first hydrogen sulfide removing section 32, part of the high-boiling hydrocarbons is absorbed by the absorbent together with hydrogen sulfide. For this reason, the first hydrogen sulfide removing unit 32 has a function as a first separating unit that separates high boiling hydrocarbons from the first raw material. The same applies to the second hydrogen sulfide removing unit 34.
The first hydrogen sulfide removing section 32 and the second hydrogen sulfide removing section 34 may be the same or different.

(Second separation unit)
The second separation unit 22 is a device that separates high-boiling hydrocarbons having a boiling point equal to or higher than the boiling point of propane from the first raw material, similarly to the first separation unit 20 in the first embodiment described above.
The second separation unit 22 may be the same as or different from the first separation unit 20 in the first embodiment described above.

(Mixing section)
The mixing unit 42 is a device that mixes the second raw material containing a high-boiling-point hydrocarbon and the hydrogen sulfide-absorbed agent, similarly to the mixing unit 40 in the above-described first embodiment.
Examples of the mixing unit 42 include a batch type mixing device and an in-line type mixing device.
The mixing section 42 may be the same as or different from the mixing section 40.

The absorbent supply source 52 may be the same as or different from the absorbent supply source 50 in the above-described first embodiment.
The pumps 72 to 74 may be the same as or different from the pumps 70 to 71 in the first embodiment described above.
The compressor 92 may be the same as or different from the compressor 90 in the first embodiment described above.

Next, a method for removing hydrogen sulfide from the first raw material using the hydrogen sulfide removing device 2 will be described.
This embodiment has a hydrogen sulfide removing step and a mixing step, and a second step of separating a high-boiling hydrocarbon from the first raw material treated in the hydrogen sulfide removing step after the hydrogen sulfide removing step. The method further includes a separation step.

From the first raw material, moisture and sludge are removed by the separator 12, and thereafter, heavy metals such as mercury vapor are removed by the heavy metal removing unit 14. The first raw material from which heavy metals such as moisture and sludge have been removed is supplied to the first hydrogen sulfide removing unit 32 via the pipe L1 '.
The absorbent is supplied from the absorbent supply source 52 to the introduction part 82 via the pipe L7 ′, the branch 106, and the pipe L6 ′. The absorbent supplied to the introduction section 82 is sprayed in an absorption tower in the second hydrogen sulfide removing section 34, and an absorption operation for absorbing hydrogen sulfide is performed (hydrogen sulfide removing step).
The sprayed absorbent absorbs hydrogen sulfide and is collected as an absorbent at the bottom of the absorption tower. A part of the spray is pressurized by the pump 73 from the branch 105 and circulates through the pipe L6 '. The absorbent that has overflowed from the pipe L6 ′ is supplied to the introduction section 84 via the pipe L4 ′, the branch 104, and the pipe L9. The absorbed agent supplied to the introduction section 84 is sprayed in an absorption tower in the first hydrogen sulfide removal section 32, and an absorption operation for absorbing hydrogen sulfide is performed. The sprayed absorbent further absorbs hydrogen sulfide and is collected at the bottom of the absorption tower, and a part thereof is pressurized by the pump 72 from the branch 103 and circulates in the pipe L9.
Further, the absorbed agent that has absorbed the hydrogen sulfide is pressurized by the pump 74 in the pipe L3 ′, and is supplied as a liquid at room temperature to the mixing section 42 via the pipe L3 ′.

On the other hand, the first raw material from which hydrogen sulfide and a part of the high-boiling-point hydrocarbon have been removed in the first hydrogen sulfide removing section 32 is supplied to the second hydrogen sulfide removing section 34 via the pipe L2 '. .
The first raw material from which hydrogen sulfide and some of the high-boiling hydrocarbons have been further removed in the second hydrogen sulfide removing section 34 is supplied to the second separating section 22 via a pipe L5 '.
In the second separation section 22, hydrogen sulfide has been removed from the supplied first raw material (second separation step). Therefore, the gas from which the high-boiling hydrocarbons have been separated in the second separation section 22 can be carried out to the outside via the pipe L11 as the target gas.

On the other hand, the second raw material containing a high-boiling-point hydrocarbon is compressed by the compressor 92 and supplied to the mixing section 42 as a liquid at room temperature via the pipe L10.
In the mixing section 42, the absorbed agent supplied from the pipe L3 'and the second raw material supplied from the pipe L10 are mixed (mixing step). The mixture of the absorbent and the second raw material mixed in the mixing section 42 is supplied to the LPG tank 60 via the pipe L8 'as a liquid containing hydrogen sulfide.

In this embodiment, the absorbed agent mixed with LPG can easily remove the LPG component by reducing the pressure. The absorbed agent from which the LPG component has been removed can be regenerated by a regenerating process as needed to be used as an absorbent. The hydrogen sulfide removed in the regeneration process can be processed by existing hydrogen sulfide processing equipment. In this case, the solvent (diluting solvent) of the absorbent is preferably kerosene, toluene or the like.
The present embodiment is particularly effective when the scale is small and the LPG component is small (for example, the concentration is less than 1% by volume), and the efficiency is high in that a large-scale facility such as a slag catcher is not required.
In addition, since the LPG component can be absorbed and transported by the absorbent, the equipment can be simplified.

[Third embodiment]
Next, a hydrogen sulfide removing device according to a third embodiment of the present invention and a hydrogen sulfide removing method using the device will be described. Hereinafter, FIG. 3 will be described focusing on portions different from the first embodiment and the second embodiment described above. FIG. 3 is a system diagram showing a configuration of the hydrogen sulfide removing device according to the third embodiment of the present invention. As shown in FIG. 3, the hydrogen sulfide removing device 3 includes an absorbent supply source 54, a first separating unit 24, a hydrogen sulfide removing unit 36, a heavy metal removing unit 14, a moisture removing unit 16, , A mixing section 44, and pipes L12 to L24.

A first separation unit 24 is provided downstream of the raw material supply source 10, and the raw material supply source 10 and the first separation unit 24 are connected by a pipe L12. A hydrogen sulfide removing unit 36 is provided downstream of the first separating unit 24, and the first separating unit 24 and the hydrogen sulfide removing unit 36 are connected by a pipe L13. A pipe L <b> 14 is connected to a stage subsequent to the first separation unit 24.
A pipe L15 is connected to the subsequent stage of the raw material supply source 18, and is connected to a branch 109 provided in the pipe L17. The pipe L15 merges with the pipe L14 at the branch 107, merges with the pipe L16 at the branch 108, and merges with the pipe L17 at the branch 109.
A pipe L16 is connected to a stage subsequent to the absorbent supply source 54, and merges with the pipe L15 at a branch 108.
The heavy metal removing unit 14 and the mixing unit 44 are provided downstream of the hydrogen sulfide removing unit 36. The hydrogen sulfide removing unit 36 and the heavy metal removing unit 14 are connected by a pipe L18. The hydrogen sulfide removing unit 36 and the mixing unit 44 are connected by a pipe L19. The pipe L19 is provided with a branch 110. The pipe L17 branches off at a branch 110 and is connected to an introduction section 86 provided in the hydrogen sulfide removing section 36. The pipe L17 is provided with a pump 75.
A moisture removing section 16 is provided at a stage subsequent to the heavy metal removing section 14, and the heavy metal removing section 14 and the moisture removing section 16 are connected by a pipe L18. A second separation unit 26 is provided downstream of the water removal unit 16, and the water removal unit 16 and the second separation unit 26 are connected by a pipe L18. The pipes L20 to L22 are connected to the second separation section 26.
A mixing section 44 is provided downstream of the second separation section 26, and the second separation section 26 and the mixing section 44 are connected by a pipe L23.
A pipe L24 is connected to a stage subsequent to the mixing section 44.

(Moisture removal section)
The moisture removing unit 16 is a device that removes moisture such as water vapor from the first raw material.
As the moisture removing unit 16, a known device that removes moisture from natural gas, crude oil, or the like may be used. Examples of the water removing unit 16 include a device that removes water in the first raw material using a hydrophilic filter.

The second separation unit 26 is a device that separates a high-boiling hydrocarbon having a boiling point equal to or higher than the boiling point of propane from the first raw material, similarly to the first separation unit 20 in the first embodiment described above.
The second separation unit 26 may be the same as or different from the first separation unit 20 in the above-described first embodiment.

The hydrogen sulfide removing unit 36 is a device that removes hydrogen sulfide by bringing the first raw material into contact with an oil-soluble hydrogen sulfide absorbing agent, similarly to the hydrogen sulfide removing unit 30 in the above-described first embodiment.
The hydrogen sulfide removing unit 36 may be the same as or different from the hydrogen sulfide removing unit 30 in the above-described first embodiment.

The mixing unit 44 is a device that mixes the second raw material containing a high-boiling-point hydrocarbon and the hydrogen sulfide-absorbed agent, similarly to the mixing unit 40 in the above-described first embodiment.
Examples of the mixing unit 44 include a batch type mixing device and an in-line type mixing device.
The mixing section 44 may be the same as or different from the mixing section 40.

The raw material supply source 18 may be the same as or different from the raw material supply source 10 in the above-described first embodiment.
The absorbent supply source 54 may be the same as or different from the absorbent supply source 50 in the above-described first embodiment.
The pump 75 may be the same as or different from the pumps 70 to 71 in the first embodiment described above.

Next, a method for removing hydrogen sulfide from the first raw material using the hydrogen sulfide removing device 3 will be described.
This embodiment is a preferred embodiment when the high boiling point hydrocarbon in the first raw material is relatively large.
This embodiment includes a first separation step, a hydrogen sulfide removal step, and a mixing step, and a pre-mixing step of mixing the high-boiling hydrocarbon and the hydrogen sulfide absorbent obtained in the first separation step. Have more. In the hydrogen sulfide removing step, the first raw material is brought into contact with the mixture obtained in the premixing step.

  The first raw material is supplied from the raw material supply source 10 to the first separation unit 24 via the pipe L12. In the first separation section 24, a second raw material containing a high boiling point hydrocarbon is separated from the first raw material (first separation step). The first separation unit 24 may be the same as the above-described separation unit, or may be different. In the present embodiment, the first separation unit 24 also functions as a separator and a slag catcher. The second raw material separated in the first separation unit 24 is a so-called condensate oil containing an alkane having 3 to 4 carbon atoms and mainly containing an alkane having 5 to 10 carbon atoms. Condensate oil is a hydrocarbon that is liquid at normal temperature and pressure obtained during the process of collecting and refining natural gas from natural gas fields.It is extremely light and more naphtha than general crude oil obtained from oil fields. It is a close property. The condensate oil merges with naphtha, kerosene, and the like supplied from the raw material supply source 18 at a branch 107 provided in the pipe L15 via the pipe L14.

  The absorbent is supplied from the absorbent supply source 54 to the branch 108 via the pipe L16, and merges with a mixture of condensate oil, naphtha, kerosene, and the like. In the branch 108, the condensate oil, naphtha, kerosene and the like are mixed with the absorbent (preliminary mixing step), and the mixture is supplied to the branch 109 provided in the pipe L17 via the pipe L15. The mixture in the pipe L17 is supplied to the introduction unit 86 by the pump 75. The mixture of the absorbent and the high-boiling hydrocarbon supplied to the introduction unit 86 is sprayed in an absorption tower in the hydrogen sulfide removing unit 36, and an absorption operation for absorbing hydrogen sulfide is performed (hydrogen sulfide removing step). The mixture of the sprayed absorbent and the high-boiling-point hydrocarbon is recovered as an absorbent at the bottom of the absorption tower, and a part thereof is pressurized by the pump 75 from the branch 110 and circulates in the pipe L17.

  In the present embodiment, the introduction unit 86 introduces a mixture of condensate oil, high-boiling hydrocarbons such as naphtha and kerosene, and an absorbent into the hydrogen sulfide removal unit 36. In the point that the absorbent introduced into the hydrogen sulfide removing unit 36 has already been mixed with the high boiling point hydrocarbon, the introducing unit 86 of the present embodiment is different from the introducing unit 80 of the first embodiment described above and the second embodiment. Are different from the introduction unit 82 and the introduction unit 84 in FIG.

The mixture of the absorbent that has absorbed hydrogen sulfide and the high-boiling hydrocarbon is supplied to the mixing section 44 via the pipe L19 as a liquid absorbent.
In the present embodiment, since the absorbed agent moves as a liquid at room temperature in the pipe L19, a compressor is not required in the pipe L19.

  On the other hand, the first raw material from which hydrogen sulfide has been removed is supplied to the second separation unit 26 via the pipe L18. In the first raw material, heavy metals such as mercury vapor are removed by a heavy metal removing unit 14, and then moisture such as water vapor is removed by a moisture removing unit 16. The first raw material from which heavy metals and moisture have been removed is supplied to the second separation unit 26 via the pipe L18.

In the second separation section 26, the first raw material from which hydrogen sulfide, heavy metal components, and moisture have been removed is separated into an inert gas component such as carbon dioxide, an LNG component, an LPG component, and a condensate oil component. You. The separated inert gas component is discharged to the outside via a pipe L20, and the LNG component is shipped as a product via a pipe L21. The separated LPG component is shipped as a product via a pipe L22, and the condensate oil component is supplied to a mixing unit 44 via a pipe L23.
In the mixing section 44, the absorbed agent and the condensate oil component are mixed (mixing step) and supplied to an external petroleum refining facility or the like via a pipe L24.

In the present embodiment, since the absorbent that has absorbed hydrogen sulfide is liquid even at room temperature, there is an advantage that a transportable absorbent does not require a pressure-resistant container even at room temperature.
Further, in the present embodiment, instead of LNG of natural gas, GTL (gas to liquids, liquid fuel) or other liquefaction processing can be used.

Although the LPG of the present embodiment contains hydrogen sulfide, the concentration of hydrogen sulfide is reduced by mixing the second raw material and the absorbent, so that LPG can be shipped as a product.
In addition, when storing and transporting in a pressure-resistant container such as LPG, a small amount of hydrogen sulfide released from the absorbed agent can be used as an odorant, and gas leakage can be checked during storage and transport of semi-finished products. There are advantages.

As described above, according to the hydrogen sulfide removing device of the present invention, hydrogen sulfide can be efficiently removed from the first raw material. As a result, high quality LNG can be obtained. In addition, in the hydrogen sulfide removing device of the present invention, since the oil-soluble hydrogen sulfide absorbent is used, the absorbent that has absorbed hydrogen sulfide is also oil-soluble, and the absorbent is mixed with the high-boiling hydrocarbon. Thereby, LPG can be obtained.
Further, according to the hydrogen sulfide removing apparatus of the present invention, not only hydrogen sulfide but also mercaptans having an SH (thiol) bond (generically referred to as hydrogen sulfide) can be removed.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes a design and the like within a range not departing from the gist of the present invention.
For example, the above-described hydrogen sulfide removing device 2 has two hydrogen sulfide removing units, but the number of hydrogen sulfide removing units may be three or four or more. As the number of hydrogen sulfide removing units increases, the scale of the plant increases, but the concentration of hydrogen sulfide contained in the first raw material can be further reduced.
Further, in the present embodiment, the case where LPG is obtained as a high-boiling-point hydrocarbon has been described. However, the LPG and crude oil may be mixed to obtain crude oil, and crude oil may be shipped.

  By using the hydrogen sulfide removing device and the hydrogen sulfide removing method of the present invention, hydrogen sulfide contained in the first raw material can be removed, and a purified target gas can be produced. Further, a high value-added LPG or the like can be obtained without discharging a large amount of waste. Furthermore, compared with the case where hydrogen sulfide is removed by the amine absorption method, a regeneration process is not required, the size of the plant can be reduced, and hydrogen sulfide can be removed efficiently. In addition, even in small-scale oil and gas fields, hydrogen sulfide can be easily removed at the production site, and energy can be saved.

1, 2, 3 hydrogen sulfide removing apparatus 10, 18 raw material supply source 12 separator 14 heavy metal removing section 16 moisture removing section 20, 24 first separating section 22, 26 second separating section 30, 32, 34, 36 hydrogen sulfide Removal unit 40, 42, 44 Mixing unit 50, 52, 54 Absorbent supply source 60 LPG tank 70-75 Pump 80, 82, 84, 86 Introducing unit 90, 92 Compressor 101-110 Branch L1-L24, L1'-L8 ' Piping

Claims (10)

A hydrogen sulfide removing unit that removes the hydrogen sulfide by contacting a first raw material containing a hydrocarbon and hydrogen sulfide with an oil-soluble hydrogen sulfide absorbent,
A mixing section for mixing a second raw material containing a high-boiling hydrocarbon having a boiling point equal to or higher than the boiling point of propane and a hydrogen sulfide-absorbed absorbent obtained by absorbing the hydrogen sulfide into the hydrogen sulfide absorbent,
A hydrogen sulfide removing device, comprising:   2. The hydrogen sulfide removal device according to claim 1, further comprising a first separation unit that separates the high-boiling-point hydrocarbon from the first raw material before the hydrogen sulfide removal unit. 3.   3. The method according to claim 1, further comprising: a second separation unit that separates the high-boiling-point hydrocarbon from the first raw material processed in the hydrogen sulfide removal unit, at a subsequent stage of the hydrogen sulfide removal unit. 4. The hydrogen sulfide removing device according to the above.   The method according to claim 2, further comprising: an introduction unit that introduces a mixture of the high-boiling-point hydrocarbon and the hydrogen sulfide absorbent obtained in the first separation unit into the hydrogen sulfide removal unit. Hydrogen sulfide removal device. A hydrogen sulfide removing step of removing the hydrogen sulfide by contacting a first raw material containing hydrocarbons and hydrogen sulfide with an oil-soluble hydrogen sulfide absorbent,
A mixing step of mixing a second raw material containing a high-boiling hydrocarbon having a boiling point equal to or higher than the boiling point of propane and a hydrogen sulfide-absorbed absorbent obtained by absorbing the hydrogen sulfide into the hydrogen sulfide absorbent,
A method for removing hydrogen sulfide, comprising:   The method for removing hydrogen sulfide according to claim 5, further comprising a first separation step of separating the high-boiling-point hydrocarbon from the first raw material before the hydrogen sulfide removal step.   The method according to claim 5, further comprising, after the hydrogen sulfide removing step, a second separating step of separating the high-boiling hydrocarbon from the first raw material treated in the hydrogen sulfide removing step. The method for removing hydrogen sulfide according to the above.   A premixing step of mixing the high-boiling-point hydrocarbon obtained in the first separation step with the hydrogen sulfide absorbent, wherein the hydrogen sulfide removal step is obtained in the premixing step with the first raw material. The method for removing hydrogen sulfide according to claim 6, wherein the mixture is brought into contact with the mixture.   The said mixing process WHEREIN: The said 2nd raw material and the said hydrogen sulfide absorbing agent are mixed on condition that the said high boiling point hydrocarbon will be in a pressurized liquefied state, The any one of Claims 5-8 characterized by the above-mentioned. The method for removing hydrogen sulfide according to claim 1.   The method for removing hydrogen sulfide according to any one of claims 5 to 8, wherein the high boiling point hydrocarbon is a liquid at room temperature.

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