Reactor system and method thereof for degassing sulfur

Abstract

A system may include a contactor column that includes a first inlet for receiving a first stream. The first stream may include a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof. The contactor column may also include a second inlet for receiving a second stream. The second stream may include a stripping medium. A partial pressure of oxygen within the contactor column may be at least about 7 psia (47 kPa absolute). The contactor column may also include a packing disposed within the contactor column.

Description

REACTOR SYSTEM AND METHOD THEREOF FOR DEGASSING SULFURCROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority7to U.S. Provisional Patent Application No. 63 / 593.470 filed on October 26, 2023 and entitled REACTOR SYSTEM AND METHOD THEREOF FOR DEGASSING SULFUR”, which is incorporated herein by reference in its entirety7.TECHNICAL FIELD

[0002] The present disclosure relates to a reactor system and method thereof for degassing sulfur.BACKGROUND

[0003] Removal of hazardous hydrogen sulfide (H2S) from various waste gases, such as those gases produced during refinement of petroleum products may be accomplished via the Claus process, which may be generally characterized according to the following net reaction:H2S + * / 2O2 -MUO+S

[0004] However, the liquid sulfur produced by plants using the Claus process can be extremely difficult to handle. More particularly, hydrogen sulfide gas may either dissolve in the liquid sulfur product or may result from the gradual decomposition of poly sulfides (H2SX) present in the liquid sulfur during the Claus conversion and recovery process. That is, the polysulfides can degrade to toxic, odorous, and highly flammable hydrogen sulfide. The dissolved hydrogen sulfide may pass into the gas phase by physical desorption. Liquid sulfur degassing or “degasification” can remove a dissolved hydrogen sulfide and polysulfides from a recovered liquified sulfur. Consequently, degasification systems and process must not only remove hydrogen sulfide, but must also remove polysulfides in order to prevent the subsequent generation and accumulation of additional hydrogen sulfide.

[0005] Nonetheless, improvements in degasification processes are needed.SUMMARY

[0006] A system may comprise a contactor column. The contactor column may comprise a first inlet for receiving a first stream. The first stream may comprise a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof. The contactor column may also comprise a second inlet for receiving a second stream, the second stream comprising a stripping medium, wherein a partial pressure of oxygen within the contactor column is at least about 7 psia (47 kPa absolute). The contactor column may also comprise a packing disposed within the contactor column.

[0007] A method of degassing hydrogen sulfide in a liquid sulfur may comprise providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof. The method may also comprise providing through a second inlet of the contactor column an oxygen-enriched stripping medium. A partial pressure of oxygen within the contactor column may be at least about 7 psia (47 kPa absolute).

[0008] A system may comprise a contactor column. The contactor column may comprise a first inlet for receiving a first stream, the first stream comprising a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof. The contactor column may also comprise a second inlet for receiving a second stream, the second stream comprising a stripping medium. The contactor column may also comprise a liquid / vapor catalyst disposed within the contactor column. The contactor column may also comprise a packing disposed within the contactor column.

[0009] A method of degassing hydrogen sulfide in a liquid sulfur may comprise providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof. The first stream may include the liquid sulfur is in contact with a liquid / vapor catalyst within the contactor column. The method may also comprise providing through a second inlet of the contactor column a stripping medium.

[0010] These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following figures illustrate embodiments of the subject matter disclosed herein. The claimed subject matter may be understood by reference to the following description taken in conjunction with the accompanying figures, in which:

[0012] FIG. 1 illustrates a system, an apparatus, and a method or process for liquid sulfur degassing according to one or more embodiments disclosed herein; and

[0013] FIG. 2 illustrates a system, an apparatus, and a method or process for liquid sulfur degassing according to one or more embodiments disclosed herein.DESCRIPTION

[0014] It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed process and apparatus may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, andtechniques illustrated hereinbelow, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents. Thus, while multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, some embodiments, as disclosed herein, are capable of modifications in various aspects without departing from the spirit and scope of the claims as presented herein. Accordingly, the detailed description hereinbelow is to be regarded as illustrative in nature and not restrictive.

[0015] In plants having sulfur degasification systems and processes, the degasification systems and processes may remove polysulfides by conversion of the polysulfides to hydrogen sulfide, which may be subsequently removed and processed in downstream units. The converted hydrogen sulfides, which may be dissolved in the liquid sulfur, may be removed from the liquid sulfur by a stripping medium. However, the conversion of polysulfides to hydrogen sulfides is the rate-limiting step with respect to the removal of polysulfides. Disclosed herein are embodiments of systems, apparatuses, compositions, and methods effective for improving the conversion of polysulfide to hydrogen sulfide. For example, in some embodiments, the systems, apparatuses, compositions, and methods disclosed herein increase the conversion rate of polysulfide to hydrogen sulfide by the use of catalysts exhibiting improved catalysis of conversion of polysulfide to hydrogen sulfide. This can allow for smaller equipment such as stripping columns to be used in new systems and / or higher throughputs to be achieved with existing equipment.

[0016] In some embodiments, the partial pressure of oxygen may be increased in the degasification system to increase the conversion rate of polysulfides. Not intending to be bound by theory’, oxygen may be effective to catalyze and / or promote the conversion of dissolved polysulfide to hydrogen sulfide. For example, in various embodiments, the partial pressure of oxygen may be increased by increasing the overall operating pressure of the degasification system and / or by increasing the concentration of oxygen in the stripping medium that is used to remove dissolved hydrogen sulfides from the liquid sulfur.

[0017] Additionally, or alternatively, in some embodiments a liquid / vapor catalyst that is effective to enhance conversion of dissolved polysulfide to hydrogen sulfide may be used. For example, in various embodiments, the liquid / vapor catalyst may be an amine-containing catalyst such as morpholine, ammonia, urea, quinoline, or alkanolamine. Not intending to be bound by theory, the conversion of dissolved polysulfide to hydrogen sulfide is mass transfer dependent, meaning that conversion of dissolved polysulfide to hydrogen sulfide is dependent upon thesurface area providing contact between the liquid vapor catalyst and the polysulfide. Also, not intending to be bound by theory, a liquid / vapor catalyst as disclosed herein may exhibit improved conversion of polysulfide to hydrogen sulfide. In various embodiments, the liquid / vapor catalyst may be injected at various points in the degassing system.

[0018] Referring to FIG. 1, an embodiment of a degasification system 100 for the enhanced conversion and removal of poly sulfides is illustrated. In the embodiment of Figure 1, the degasification system 100 generally includes a contactor 20, a liquid sulfur source 30, and a sulfur recovery unit (SRU) 40. In the embodiment of FIG. 1, the degasification system 100 is generally configured to increase the partial pressure of oxygen used in the degasification system, for example, the partial pressure of oxygen within the contactor 20. As will be disclosed herein, the increase in the partial pressure of oxygen, as disclosed herein, may be effective to improve the conversion of dissolved polysulfide to hydrogen sulfide.

[0019] The SRU 40 may be a Claus SRU. For example, the SRU 40 may generally be configured to utilize a thermal stage, for example, at least one reaction furnace and a catalytic stage such as at least one Claus reactor, to convert gases (e.g., sulfur dioxide (SO2) and H2S) received as an acid gas stream from various sources to elemental sulfur (in gaseous phase) and water. The reaction product, for example, a mixture of gaseous sulfur and water, can be cooled (e.g., via one or more heat exchangers) to recover liquid elemental sulfur, for example, as recovered a liquid sulfur stream 44. Other components may remain in a gaseous phase and may be emitted from the SRU 40 as a tail gas stream. For example, the tail gas stream may predominantly include H2, H2S, SO2, H2O, CO2, Nz and small amounts of other sulfur-containing species (e.g., sulfur (S), carbon disulfide (CS2), carbonyl sulfide (COS)).

[0020] Although the embodiment of Figure 1 discusses the SRU 40 (e.g., a Claus SRU) as producing the liquid sulfur stream 44, in alternative embodiments, the liquid sulfur stream 44 may be produced or derived from any other process that likewise yields a liquid sulfur stream 44. For example, while the degasification system 100 in the embodiment of FIG. 1 is discussed as comprising a Claus SRU, for example, which may be disposed at a refinery' or gas processing plant, a liquid sulfur stream like the liquid sulfur stream of FIG. 1 may result from processes in various other settings.

[0021] Also, in the embodiment of FIG. 1, the liquid sulfurs stream 44 is directed to the liquid sulfur source 30. In some embodiments, the liquid sulfur source 30 comprises a sulfur pit, for example, which accumulates the liquid sulfur stream 44 from the SRU 40. A low pressure sweep gas 46 may be circulated through the liquid sulfur source 30. for example, to remove hydrogen sulfide gas 48 from a vapor space above the liquid sulfur. Additionally, in someembodiments, the liquid sulfur source 30 may include a liquid sulfur pump 60, for example, suitable for fluidly communicating the liquid sulfur out of the sulfur source (e.g., to the contactor 20).

[0022] The contactor 20 can include a contactor column 22 having a first inlet 24, a second inlet 26, and an optional packing 28 (e.g., a structured packing, unstructured packing, trays, etc.). In some aspects, the contactor column 22 can serve as a degassing contactor. The contactor column 22 can be made of any suitable material (for example, carbon steel or other materials inert to oxidizing gases, liquid sulfur, and / or moist hydrogen sulfide gas).

[0023] The degasification system 100 may be configured such that the first inlet 24 receives a first stream 32 including liquid sulfur comprising polysulfide, dissolved hydrogen sulfide, or combinations thereof taken from the liquid sulfur source. In various embodiments, the first stream 32 may be pumped into the contactor column 22 from any suitable source of liquid sulfur. For example, in the embodiment of FIG. 1, the first stream 32 is illustrated as being pumped, for example, via the liquid sulfur pump 60, from the liquid sulfur source 30, which is illustrated as a sulfur pit used to accumulate liquid sulfur from the SRU 40. The first stream 32 may be heated or cooled to a temperature range from about 250°F (120°C) to about 295°F (150°C), or a range of about 265°F (130°C) to about 285°F (140°C) prior to being pumped into the contactor column 22. In some embodiments, a cooler 50 is provided to cool the first stream to a desired temperature. For example, in the embodiment of FIG. 1, the cooler 50 is illustrated as a heat exchanger that is configured to cool the first stream via heat exchange with a boiler feed water stream 42 taken from and supplied to the SRU 40, although in additional or alternative embodiments a first stream may be air-cooled. In various embodiments, the temperature of the first stream 32 may be selected so as to maintain the liquid sulfur at a desired viscosity. In some aspects, the first stream 32 may include dissolved hydrogen sulfide and polysulfide, for example, in an amount up to about 600 ppmw, 400 ppmw, or 350 ppmw, for example, from about 300 to about 350 ppmw of dissolved hydrogen sulfide and polysulide.

[0024] The degasification system 100 may be configured such that the second inlet 26 receives a second stream 34. In some embodiments, for example, as illustrated in the embodiment of Figure 1. the second stream 34 may generally comprise an oxy gen-containing stripping medium, such as an oxygen-enriched stripping medium. For example, as illustrated, the second stream 34 is formed by mixing an oxygen-enrichment stream 36 and a stripping medium 38.

[0025] In some embodiments, the stripping medium 38 may be air, for example, air derived as an off-gas from one or more other processes associated with the plant at which thedegasification system 100 is disposed. For example, in some embodiments, the stripping medium 38 may comprise all or a portion of a tail gas derived from a Claus sulfur converter process (such as the SRU 40), for example, which may comprise one or more inert gasses as disclosed herein. Additionally, or alternatively, the stripping medium 38 comprise suitable inert gas, for example, one or more of gaseous elements, such as nitrogen, helium, neon, argon, krypton, xenon, or radon. In some embodiments, an inert gas can also include carbon dioxide, although carbon dioxide may be chemically reactive when exposed to moisture or high heat. In some embodiments, the stripping medium 38 may include less than 1.0% water vapor, by weight, additionally or alternatively, less than 0.5% water vapor, by weight, additionally or alternatively, less than 0.1% water vapor, by weight, additionally or alternatively, less than 0.05% water vapor, by weight, additionally or alternatively, less than 0.01% water vapor, by weight, additionally or alternatively, less than 0.005% water vapor, by weight, additionally or alternatively, less than 0.001% water vapor, by weight, additionally or alternatively, less than 0.0005% water vapor, by weight, additionally or alternatively, less than 0.0001% water vapor, by weight, additionally or alternatively, less than 0.00005% water vapor, by weight, additionally or alternatively, less than 0.00001% water vapor, by weight.

[0026] The oxygen-enrichment stream 36 may, generally, comprise oxygen in an amount greater than the amount of oxygen in ambient, for example, greater than about 21% by volume. For example, the oxygen-enrichment stream 36 may comprise oxygen in an amount of at least more than 21% by volume, or at least about 25% by volume, or at least about 30% by volume, or at least about 35% by volume, or at least about 40% by volume, or at least about 45% by volume, or at least about 50% by volume, or at least about 55% by volume, or at least about 60% by volume, or at least about 65% by volume, or at least about 70% by volume, or at least about 75% by volume, or at least about 80% by volume, or at least about 85% by volume, or at least about 90% by volume, or at least about 95% by volume, or at least about 97% by volume, or at least about 98% by volume, or at least about 99% by volume, or at least about 99.5% by volume, or at least about 99.9% by volume, or about 100% by volume. In various embodiments, the oxygen-enrichment stream 36 may be provided by any suitable source of oxy gen-containing gas. For example, the oxygen-enrichment stream 36 can obtain oxygen at a desired purity from an oxygen storage tank, or via a process known in the art, for example, the separation of air into nitrogen and oxygen, such as pressure swing adsorption (PSA), vacuum swing adsorption (V SA), or cry ogenic separation techniques.

[0027] The contactor column 22 can be operated under any suitable conditions, for example, under a suitable pressure, to increase oxygen partial pressure. In some embodiments, the oxygen-enrichment stream 36 may be mixed with the stripping medium 38 to form the second stream 34 in amounts sufficient that, when the second stream 34 is introduced into the contactor column 22, the partial pressure of oxygen in the contactor column 22 is increased relative to conventional columns. For example, the partial pressure of oxygen in the contactor column 22 may be at least more than 7 pounds per square inch absolute (psia) (47 kilopascal (kPa) absolute), additionally or alternatively, at least 20 psia (140 kPa absolute) additionally or alternatively, at least 30 psia (210 kPa absolute), additionally or alternatively, at least about 40 psia (280 kPa absolute), additionally or alternatively, at least about 50 psia (340 kPa absolute), additionally or alternatively, at least about 60 psia (410 kPa absolute), additionally or alternatively, at least about 70 psia (480 kPa absolute), additionally or alternatively, at least about 80 psia (550 kPa absolute), additionally or alternatively, at least about 90 psia (620 kPa absolute), additionally or alternatively, at least about 100 psia (690 kPa absolute), for example, from about 30 psia (210 kPa absolute) to about 150 psia (1030 kPa absolute), additionally or alternatively, from about 40 psia (280 kPa absolute) to about 120 psia (830 kPa absolute).

[0028] Additionally or alternatively, in some embodiments, the contactor column 22 may be operated at a total pressure (e.g., a system operating pressure) up to about 250 pounds per square inch gauge (psig) (1720 (kPa(g)), additionally or alternatively, at least about 21 psig (140 kPa(g)), additionally or alternatively, from about 25 psig (170 kPa(g)) to about 200 psig (1380 kPa(g)), additionally or alternatively, from about 40 psig (280 kPa(g)) to about 180 psig (1240 kPa(g)), additionally or alternatively, from about 50 psig (340 kPa(g)) to about 150 psig (1030 kPa(g)).In some embodiments, the operating pressure range may be established based upon the partial pressure of oxygen in the contactor column.

[0029] In some embodiments, the second stream 34 can be heated from about 150°F (66°C) to about 200°F (93°C) prior to being introduced into the contactor column 22. Additionally, for example, in some embodiments the second stream 34 may be compressed, such as via a blower or any other suitable device, and provided to second inlet 26. In some embodiments, the flow rate of the second stream 34 at the second inlet 26 may be established based upon factors including the flow rate of the first stream 32, the concentration of oxygen in the second stream 34. the total pressure in the contactor column 22 (e.g., system operating pressure), or combinations of these. While the ratio of the first stream 32 and the second stream 34 may be supplied to the contactor column 22 at any suitable ratio, in some embodiments the molar ratio will range from about 10: 1 to about 60:1 or, additionally or alternatively, from about 20: 1 to about 50:1.

[0030] Generally, the first stream 32 (e.g., the liquid sulfur) may be introduced into the contactor column 22 at a location at or above the location where the second stream 34 (e.g., the oxygen-enriched stripping medium) is introduced. For example, in some embodiments, the first inlet 24, via which the first stream 32 may be introduced, may be disposed in an upper portion of the contactor column 22, for example, an upper half, upper one-third, upper one-quarter, or upper one-fifth of the contactor column 22. Additionally, or alternatively, in some embodiments, the second inlet 26, via which the second stream 34 may be introduced, may be disposed in a lower portion of the contactor column 22, for example, a lower half, lower one-third, lower one-quarter, or lower one-fifth of the contactor column 22.

[0031] Additionally, in some embodiments, the packing 28, which can be optional in some embodiments, can be positioned between the first inlet 24 and the second inlet 26. In some embodiments, the packing 28 may further include a material such as corrugated sheeting and / or a structured packing coated with a solid catalyst. The solid catalyst can be selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof. Moreover, the solid catalyst can be promoted with an iron oxide or an alkaline metal oxide. Positioning the solid catalyst in the packing 28 for contacting the first stream 32 and the second stream 34 can permit the combined polysulfides and hydrogen sulfide levels to be lower (for example, less than about 10 ppmw, less than about 5 ppmw, or less than 1 ppmw).

[0032] In some embodiments, the flow of the first stream 32 through the first inlet 24 can be controlled to provide a preselected residence time in the contactor column 22, to achieve a desired level of polysulfides conversion to hydrogen sulfide from the first stream 32, and to achieve a desired level of hydrogen sulfide gas removal from the first stream 32. For example, in some embodiments, the contactor may comprise a control system. The control system may, in various embodiments, can comprise or otherwise be in touch with various sensors and / or actuatable components effective to control the operation of the contactor 20. For example, in the embodiment of FIG. 1, a first control valve 62, a second control valve 64, and a third control valve 66 can be used to control the flow rates of the first stream 32, the oxy gen-enrichment stream 36. and the stripping medium 38, respectively, as well as the ratio of the oxygen-enrichment stream 36 to the stripping medium 38 and the overall flow rate of the second stream 34. Also, in the embodiment of the FIG. 1, a level controller 72 can control the level of fluids in the contactor column 22, for example, so as to maintain the packing 28 submerged by regulating the flow a sulfur product 80 out of the contactor column 22. The sulfur product 80 may be characterized as having less than about 10 ppmw, or less than 5 ppmw; or less than 1 ppmw hydrogen sulfide.The sulfur product 80 may be directed to storage as a product stream 84 via a fourth manual or control valve 76, or retumed / recycled to the liquid sulfur source 30 (e.g.. a sulfur pit) as a sulfur recycle stream 82 via a fifth manual or control valve 74. Also, a sixth control valve 68 (e.g., a pressure controller) can control the flow of an off-gas stream 86 from the contactor column 22 which, in the embodiment of FIG. 1, may be optionally directed to the SRU 40. For example, the off-gas stream 86 can contain the hydrogen sulfide, SO2, N2, CO2, and trace amounts of elemental sulfur formed in the contactor column 22, and can be sent to the SRU burner in the SRU 40, to an incinerator, or to a treatment process.

[0033] In some embodiments, the increased partial pressure of oxygen employed in the degasification system 100 of FIG. 1, more particularly, within the contactor 20. may be effective to increase the conversion of polysulfide to hydrogen sulfide. For example, and not intending to be bound by theory, the provision of oxygen within the contactor 20 at the partial pressures as disclosed herein may be effective to catalyze and / or enhance the conversion of dissolved polysulfide to hydrogen sulfide, which can be stripped from the liquid sulfur in the contactor via the stripping medium.

[0034] Referring to FIG. 2. an additional or alternative embodiment of a degasification system 200 for the enhanced conversion and removal of polysulfides is illustrated. In the embodiment of Figure 2 the degasification system 200 generally includes a contactor 20, a liquid sulfur source 30, and a sulfur recovery unit (SRU) 40, as similarly disclosed with respect to FIG.1. The similar elements as shown in FIG. 2 can be the same or similar to those described with respect to FIG. 1 . For example, the contactor, the liquid sulfur source 30, and the SRU 40 are configured as disclosed with respect to FIG. 1, except as further disclosed. Other like components will not be redescribed in the interest of brevity. In the embodiment of FIG. 2, the degasification system 200 is generally configured to utilize a liquid / vapor catalyst, for example, within the contactor 20. As will be disclosed herein, the use of a liquid / vapor catalyst, as disclosed herein, may be effective to improve the conversion of dissolved polysulfide to hydrogen sulfide.

[0035] As shown in FIG. 2, the degasification system 200 is generally configured to contact liquid sulfur with a liquid / vapor catalyst 236. In some embodiments, the liquid / vapor catalyst 236 may generally be configured to catalyze the conversion of dissolved polysulfide to hydrogen sulfide. In some embodiments, the liquid / vapor catalyst 236 may comprise an amine-containing catalyst. For example, in various embodiments the liquid / vapor catalyst 236 (e.g., an amine- containing catalyst) may comprise morpholine, ammonia, urea, quinoline, alkanolamine, or combinations thereof.

[0036] In various embodiments, the liquid / vapor catalyst may be contacted with the liquid sulfur at various points within the degasification system 200. As shown in FIG. 2, in some embodiments the introduction of the liquid / vapor catalyst 236 may be controlled, for example, via the controller and one or more control valves 264. For example, in the embodiment of FIG. 2, the liquid / vapor catalyst is illustrated as being introduced into the liquid sulfur source 30 so as to be contacted with the liquid sulfur, for example, into the liquid sulfur. Also, in the embodiment of FIG. 2, the liquid / vapor catalyst 236 is also illustrated as being introduced into the contactor column 22, at various locations. For example, in various embodiments, the liquid / vapor catalyst 236 may be introduced into the contactor column 22 in a relatively lower portion thereof (e.g., proximate the second inlet 26), in an intermediate portion thereof, and / or in a relatively upper portion thereof (e.g., proximate the first inlet 24). Also, for example, the liquid / vapor catalyst 236 may be introduced into the second stream 34, for example, such that the liquid / vapor catalyst 236 is introduced into the contactor column along with the second stream 34. While FIG. 2 illustrates the liquid / vapor catalyst 236 being contacted with liquid sulfur in various locations, in various embodiments the liquid / vapor catalyst 236 may be contacted with the liquid sulfur in any one of these locations or in any suitable combination of these.

[0037] In some embodiments, the use of the liquid / vapor catalyst employed in the degasification system 200 of FIG. 2 may be effective to increase the conversion of polysulfide to hydrogen sulfide. For example, and not intending to be bound by theory, the provision of a catalyst in a liquid and / or vapor phase as disclosed herein may be effective to catalyze and / or enhance the conversion of dissolved polysulfide to hydrogen sulfide, which can be stripped from the liquid sulfur in the contactor via the stripping medium. In some embodiments, a liquid catalyst may be injected relative to the inlet sulfur flow at a rate from 5 to 50 ppmw, or at a rate from 50 ppmw to 200 ppmw. Additionally, a vapor catalyst may be injected at a rate relative to inlet sulfur flow or by concentration of catalyst and may be from 5 ppmv to 10 vol%, or may be from 10 vol% to 40 vol%.

[0038] In some embodiments, the liquid / vapor catalyst 236 may be used in place of a conventional catalyst, for example, a solid catalyst fixed within the contactor column 22 as disclosed with respect to FIG. 1; alternatively, in some embodiments, the liquid / vapor catalyst 236 may be used in addition to a solid catalyst fixed within the contactor column 22. Also, in some embodiments, the liquid / vapor catalyst 236 may be used together with a stripping gas such as air or with an oxygen-enriched stripping medium as was disclosed with respect to FIG. 1.

[0039] In some embodiments, the systems and methods disclosed herein, for example, with respect to FIG. 1 and / or FIG. 2, may be applicable to degassing liquid sulfur where the liquidsulfur can be formed and available; often these systems and methods can be implemented in the liquid sulfur produced from sulfur recovery units in refining, gas processing, and chemical manufacturing facilities. In some embodiments, end users can realize significant savings in both capital investment cost and operaring cost associated with degasification. For example, by improving the conversion of dissolved polysulfide to hydrogen sulfide, for example, according to the systems and methods disclosed with respect to FIG 1 and / or FIG 2, the disclosed systems and methods may be effective to decrease the residence time within the contactor 20 as necessary to attain a sulfur product having a desired residual amount of hydrogen sulfide, for example, less than about 10 ppmw, or less than 5 ppmw, or less than 1 ppmw hydrogen sulfide. The decreases in residence time (such as by decreased contactor column diameter or by increased sulfur flow through an existing degassing column) or by decreases in operating pressure may decrease both capital and operating costs associated with degasification systems and methods.

[0040] Having described various systems and methods herein, certain aspects and advantages of the discloses process and apparatus can include:

[0041] In a first aspect, a system comprises a contactor column, comprising a first inlet for receiving a first stream, the first stream comprising a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof, a second inlet for receiving a second stream, the second stream comprising a stripping medium, wherein a partial pressure of oxygen within the contactor column is at least about 7 psia (47 kPa absolute), and a packing disposed within the contactor column.

[0042] A second aspect can include the system of the first aspect, wherein the second stream comprises an oxygen-enriched stripping medium formed from an oxygen-enrichment stream and a stripping medium.

[0043] A third aspect can include the system of the second aspect, wherein the stripping medium comprises air or an inert gas.

[0044] A fourth aspect can include the wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

[0045] A fifth aspect can include the system of any one of the first to fourth aspects, further comprising a controller, wherein the controller is configured to control a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide and polysulfide.

[0046] A sixth aspect can include the system of any one of the first to fifth aspects, wherein the packing is positioned between the first inlet and the second inlet.

[0047] A seventh aspect can include the system of any one of the first to sixth aspects, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

[0048] An eighth aspect can include the system of any one of the first to seventh aspects, further comprising a sulfur recovery unit configured to receive a stream comprising oxygen and a stream comprising an acid gas to produce a stream comprising a liquid sulfur.

[0049] A ninth aspect can include the system of any one of the first to eighth aspects, wherein a system operating pressure is at least 21 psig.

[0050] A tenth aspect can include the system of any one of the first to ninth aspects, wherein a system operating pressure of within the contactor column is up to about 250 psig (1720 kPa(g)).

[0051] In an eleventh aspect, a method of degassing hydrogen sulfide in a liquid sulfur comprises: providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof, and providing through a second inlet of the contactor column an oxygen-enriched stripping medium, wherein a partial pressure of oxygen within the contactor column is at least about 7 psia (47 kPa absolute).

[0052] A twelfth aspect can include the method of the eleventh aspect, further comprising forming the oxygen-enriched stripping medium by contacting an oxygen-enrichment stream and a stripping medium.

[0053] A thirteenth aspect can include the method of the twelfth aspect, wherein the stripping medium comprises air or an inert gas.

[0054] A fourteenth aspect can include the method of the thirteenth aspect, wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

[0055] A fifteenth aspect can include the method of any one of the eleventh to fourteenth aspects, further comprising controlling, via a controller, a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide and polysulfide.

[0056] A sixteenth aspect can include the method of any one of the eleventh to fifteenth aspects, wherein the contactor column comprises packing positioned between the first inlet and the second inlet.

[0057] A seventeenth aspect can include the method of the sixteenth aspect, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

[0058] An eighteenth aspect can include the method of any one of the eleventh to seventeenth aspects, further comprising producing, in a sulfur recovery unit, a stream comprising a liquid sulfur from a stream comprising oxygen and a stream comprising an acid gas.

[0059] A nineteenth aspect can include the method of any one of the eleventh to eighteenth aspects, wherein a system operating pressure is at least 21 psig.

[0060] A twentieth aspect can include the method of any one of the eleventh to nineteenth aspects, wherein a system operating pressure of within the contactor column is up to about 250 psig (1720 kPa(g)).

[0061] In a twenty first aspect, a system comprises a contactor column, comprising a first inlet for receiving a first stream, the first stream comprising a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof, a second inlet for receiving a second stream, the second stream comprising a stripping medium, a liquid / vapor catalyst disposed within the contactor column, and a packing disposed within the contactor column.

[0062] A twenty second aspect can include the system of the twenty first aspect, wherein the second stream is formed from an oxy gen-enrichment stream and a stripping medium.

[0063] A twenty third aspect can include the system of the twenty second aspect, wherein the stripping medium comprises air or an inert gas.

[0064] A twenty fourth aspect can include the system of the twenty third aspect, wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

[0065] A twenty fifth aspect can include the system of any one of the twenty first to twenty fourth aspects, further comprising a controller, wherein the controller is configured to control a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide gas and dissolved polysulfide.

[0066] A twenty sixth aspect can include the system of any one of the twenty first to twenty fifth aspects, wherein the packing is positioned between the first inlet and the second inlet.

[0067] A twenty seventh aspect can include the system of any one of the twenty first to twenty sixth aspects, wherein the packing further comprises a corrugated sheeting coated witha solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

[0068] A twenty eighth aspect can include the system of any one of the twenty first to twenty seventh aspects, further comprising a sulfur recovery unit configured to receive a stream comprising oxygen and a stream comprising an acid gas to produce a stream comprising a liquid sulfur.

[0069] A twenty ninth aspect can include the system of any one of the twenty first to twenty eighth aspects, wherein the liquid / vapor catalyst comprises an amine-containing catalyst.

[0070] A thirtieth aspect can include the system of any one of the twenty first to twenty ninth aspects, wherein the liquid / vapor catalyst comprises morpholine, ammonia, urea, quinoline, alkanolamine, or combinations thereof.

[0071] In a thirty first aspect, a method of degassing hydrogen sulfide in a liquid sulfur comprises providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof, wherein the first stream including the liquid sulfur is in contact with a liquid / vapor catalyst within the contactor column, and providing through a second inlet of the contactor column a stripping medium.

[0072] A thirty second aspect can include the method of the thirty first aspect, further comprising, before providing the stripping medium through the second inlet, enriching the stripping medium with oxygen by contacting an oxygen-enrichment stream and the stripping medium.

[0073] A thirty third aspect can include the method of the thirty second aspect, wherein the stripping medium comprises air or an inert gas.

[0074] A thirty fourth aspect can include the method of the thirty third aspect, wherein the inert gas comprises a tail gas from a Claus sulfur recovery' unit.

[0075] A thirty fifth aspect can include the method of any one of the thirty7first to thirty fourth aspects, further comprising controlling, via a controller, a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide gas and dissolved polysulfide.

[0076] A thirty7sixth aspect can include the method of any one of the thirty first to thirty fifth aspects, wherein the contactor column comprises packing positioned between the first inlet and the second inlet.

[0077] A thirty seventh aspect can include the method of the thirty sixth aspect, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

[0078] A thirty eighth aspect can include the method of any one of the thirty first to thirty seventh aspects, further comprising producing, in a sulfur recovery unit, a stream comprising a liquid sulfur from a stream comprising oxygen and a stream comprising an acid gas.

[0079] A thirty ninth aspect can include the method of any one of the thirty first to thirty eighth aspects, wherein the liquid / vapor catalyst comprises an amine-containing catalyst.

[0080] A fortieth aspect can include the method of any one of the thirty first to thirty ninth aspects, wherein the liquid / vapor catalyst comprises morpholine, ammonia, urea, quinoline, alkanolamine, or combinations thereof.

[0081] The recitation of ranges of values herein is merely intended to sen e as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All processes described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., ‘‘such as’') provided with respect to certain embodiments herein is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosed subject matter otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the disclosed subject matter.

[0082] Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.

[0083] The following discussion provides many exemplary embodiments of the disclosed subject matter. Although each embodiment may represent a single combination of disclosed elements, the disclosed subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a secondembodiment comprises elements B and D, then the disclosed subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

[0084] While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs.

[0085] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0086] As used herein, the terms “comprise,” “comprises,” “comprising,” or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or subsystems or elements or structures preceded by “comprises [...] a” does not. without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or additional devices or additional sub-systems or additional elements or additional structures.

[0087] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection wi th the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrase “in one embodiment,” “in an embodiment,” and similar language throughout this detailed description may, but do not necessarily, all refer to the same embodiment.

[0088] As used herein, the term “zone” can refer to an area including one or more equipment items and / or one or more sub-zones. Equipment items can include one or more reactors or reactor vessels, heaters, exchangers, pipes, pumps, compressors, and controllers. Additionally, an equipment item, such as a reactor, dryer, or vessel, can further include one or more zones or subzones.

[0089] As used herein, the term “essentially no” can refer to a stream having no more than about 10 parts per million, by weight, (ppmw) or by volume (ppmv) of a substance, no more than about 1 ppmw / ppmv of a substance, or even no detectable amounts of a substance, such as nitrogen.

[0090] As used herein, the term ‘‘acid gas'’ can refer to a gas including one or more sulfur- containing compounds and carbon dioxide.

[0091] As used herein, the term “sulfur-containing compound” can refer to a chemical compound that has at least one sulfur atom.

[0092] As used herein, the term “downstream” can refer to at least a portion of material flowing to the subject may operatively flow from the object with which it communicates.

[0093] As used herein, “upstream communication” can refer to at least a portion of the material flowing from the subj ect may operatively flow to the obj ect with which it communicates .

[0094] As used here, the term “structured packing” refers to a static physical arrangement of structures or features that facilitates or enhances liquid to gas contact during countercurrent flow and / or concurrent flow.

[0095] As used herein, the term “and / or” can mean one, some, or all elements depicted in a list. As an example, “A and / or B” can mean A, B, or a combination of A and B.

[0096] While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, some embodiments, as disclosed herein, are capable of modifications in various aspects without departing from the spirit and scope of the claims as presented herein. Accordingly, the detailed description herein below7is to be regarded as illustrative in nature and not restrictive.

Claims

CLAIMSWhat is claimed is:

1. A system, comprising: a contactor column, comprising: a first inlet for receiving a first stream, the first stream comprising a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof; a second inlet for receiving a second stream, the second stream comprising a stripping medium, wherein a partial pressure of oxygen within the contactor column is at least about 7 psia (47 kPa absolute); and a packing disposed within the contactor column.

2. The system of claim 1, wherein the second stream comprises an oxygen-enriched stripping medium formed from an oxygen-enrichment stream and the stripping medium.

3. The system of claim 2, wherein the stripping medium comprises air or an inert gas.

4. The system of claim 3, wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

5. The system of claim 1. further comprising a controller, wherein the controller is configured to control a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide and polysulfide in a degassed liquid sulfur.

6. The system of claim 1, wherein the packing is positioned between the first inlet and the second inlet.

7. The system of claim 1, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

8. The system of claim 1, further comprising: a sulfur recovery7unit configured to receive a stream comprising oxygen and a stream comprising an acid gas to produce a stream comprising the liquid sulfur.

9. The system of claim 1. wherein a system operating pressure is at least 21 psig.

10. The system of claim 1, wherein a system operating pressure of within the contactor column is up to about 250 psig (1720 kPa).

11. A method of degassing hydrogen sulfide in a liquid sulfur, the method comprising: providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof; and providing through a second inlet of the contactor column an oxy gen-enriched stripping medium, wherein a partial pressure of oxygen within the contactor column is at least about 7 psia (47 kPa absolute).

12. The method of claim 11, further comprising forming the oxy gen-enriched stripping medium by contacting an oxy gen-enrichment stream and a stripping medium.

13. The method of claim 12, wherein the stripping medium comprises air or an inert gas.

14. The method of claim 13, wherein the inert gas comprises a tail gas from a Claus sulfur recovery7unit.

15. The method of claim 11, further comprising controlling, via a controller, a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide and polysulfide.

16. The method of claim 11. wherein the contactor column comprises packing positioned between the first inlet and the second inlet.

17. The method of claim 16, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

18. The method of claim 11 , further comprising: producing, in a sulfur recovery unit, a stream comprising the liquid sulfur from a stream comprising oxygen and a stream comprising an acid gas.

19. The method of claim 11, wherein a system operating pressure is at least 21 psig.

20. The method of claim 11. wherein a system operating pressure of within the contactor column is up to about 250 psig (1720 kPa(g)).

21. A system, comprising: a contactor column, comprising:a first inlet for receiving a first stream, the first stream comprising a liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof; a second inlet for receiving a second stream, the second stream comprising a stripping medium; a liquid / vapor catalyst disposed within the contactor column; and a packing disposed within the contactor column.

22. The system of claim 21, wherein the second stream is formed from an oxy genenrichment stream and the stripping medium.

23. The system of claim 22, wherein the stripping medium comprises air or an inert gas.

24. The system of claim 23, wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

25. The system of claim 21, further comprising a controller, wherein the controller is configured to control a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide gas and dissolved polysulfide.

26. The system of claim 21, wherein the packing is positioned between the first inlet and the second inlet.

27. The system of claim 21, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

28. The system of claim 21, further comprising: a sulfur recovery unit configured to receive a stream comprising oxygen and a stream comprising an acid gas to produce a stream comprising the liquid sulfur.

29. The system of claim 21, wherein the liquid / vapor catalyst comprises an amine- containing catalyst.

30. The system of claim 21, wherein the liquid / vapor catalyst comprises morpholine, ammonia, urea, quinoline, alkanolamine, or combinations thereof.

31. A method of degassing hydrogen sulfide in a liquid sulfur, the method comprising: providing through a first inlet of a contactor column a first stream including the liquid sulfur comprising a dissolved hydrogen sulfide, a polysulfide, or a combination thereof, wherein the first stream including the liquid sulfur is in contact with a liquid / vapor catalyst within the contactor column; andproviding through a second inlet of the contactor column a stripping medium.

32. The method of claim 31, further comprising, before providing the stripping medium through the second inlet, enriching the stripping medium with oxygen by contacting an oxygen-enrichment stream and the stripping medium.

33. The method of claim 32, wherein the stripping medium comprises air or an inert gas.

34. The method of claim 33, wherein the inert gas comprises a tail gas from a Claus sulfur recovery unit.

35. The method of claim 31, further comprising controlling, via a controller, a flow of the first stream through the first inlet to provide a preselected residence time in the contactor column and to achieve a desired level of residual hydrogen sulfide gas and dissolved polysulfide.

36. The method of claim 31, wherein the contactor column comprises packing positioned between the first inlet and the second inlet.

37. The method of claim 36, wherein the packing further comprises a corrugated sheeting coated with a solid catalyst, wherein the solid catalyst is selected from the group consisting of a bauxite, a titania, an alumina, a mixture of a silica with a thermally stable alumina, a mixture of a silica and a titania, and combinations thereof.

38. The method of claim 31, further comprising: producing, in a sulfur recovery unit, a stream comprising the liquid sulfur from a stream comprising oxygen and a stream comprising an acid gas.

39. The method of claim 31 , wherein the liquid / vapor catalyst comprises an amine- containing catalyst.

40. The method of claim 31, wherein the liquid / vapor catalyst comprises morpholine, ammonia, urea, quinoline, alkanolamine, or combinations thereof.

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