Liquid sulfur degassing

Abstract

A method and system for degassing liquid sulfur is disclosed. The method and system generally involve degassing liquid sulfur in a degassing vessel, and the level of liquid sulfur in the degassing vessel is controlled in the degassing vessel by determining the liquid sulfur level in the degassing vessel.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 819051, entitled “Liquid Sulfur Degassing,” filed on March 15, 2019, U.S. Provisional Patent Application No. 62 / 829332, entitled “Liquid Sulfur Degassing,” filed on April 4, 2019, and U.S. Patent Application No. 16 / 816484, entitled “Liquid Sulfur Degassing,” filed on March 12, 2020, all of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to systems and methods for degassing liquid sulfur. Background Art

[0004] Liquid sulfur degassing involves contacting liquid sulfur with a stripping gas to remove impurities contained in the liquid sulfur. Impurities may be transferred to the stripping gas, and the process produces a gaseous stream containing impurities and stripping gas and degassed liquid sulfur with a reduced amount of impurities. Techniques for degassing liquid sulfur are described in U.S. Patents Nos. 5,632,967, 8,663,595, and 10,059,588, each of which is incorporated by reference in its entirety. Control of the liquid sulfur level inside the degassing vessel where impurity stripping occurs is a continuing challenge for degassing liquid sulfur. Summary of the invention

[0005] A liquid sulfur degassing system comprises: a degassing vessel configured to receive liquid sulfur and a stripping gas therein, and configured to contact the liquid sulfur with the stripping gas so as to produce a bottom stream comprising degassed liquid sulfur and a top stream comprising the stripping gas enriched in hydrogen sulfide; and a liquid level controller directly or indirectly connected to the degassing vessel and configured to: determine a level of liquid sulfur in the degassing vessel; and control the level of liquid sulfur in the degassing vessel based on the level of liquid sulfur determined for the degassing vessel.

[0006] A liquid sulfur degassing system comprises: a degassing vessel configured to receive liquid sulfur and a stripping gas therein, and to contact the liquid sulfur with the stripping gas so as to produce a bottom stream comprising degassed liquid sulfur and a top stream comprising the stripping gas enriched in hydrogen sulfide; a bridle fluidly connected to the degassing vessel; and a liquid level controller connected to the bridle and configured to: measure a first level of liquid sulfur in the bridle; and control the level of liquid sulfur in the degassing vessel based on the first level measured for the bridle.

[0007] A method of treating liquid sulfur containing polysulfides and hydrogen sulfide includes: contacting the liquid sulfur with a stripping gas in a contacting zone of a degassing vessel; determining a level of the liquid sulfur in the degassing vessel; and controlling the level of the liquid sulfur in the degassing vessel based on the determining step.

[0008] A method for treating liquid sulfur containing polysulfides and hydrogen sulfide, comprising: contacting the liquid sulfur with a stripping gas in a contacting area of ​​a degassing vessel; and measuring a first level of the liquid sulfur in a level suppressor, the level suppressor being fluidly connected to the degassing vessel and configured to indicate a second liquid level of the liquid sulfur in the degassing vessel; and controlling the second level of the liquid sulfur in the degassing vessel based on the measuring step.

[0009] A method for retrofitting a decomposition zone to an existing degassing vessel includes one or more of the following steps: disconnecting a liquid sulfur supply stream from an inlet of the degassing vessel; attaching an outlet of a vessel structure configured to hold a decomposition catalyst to the inlet of the degassing vessel; attaching the inlet of the vessel structure to the liquid sulfur supply stream; placing a decomposition catalyst in the vessel structure; disconnecting an existing liquid level controller from the degassing vessel; attaching a level suppressor of the construction disclosed herein to the degassing vessel; and attaching the level suppressor to the existing liquid level controller or a second liquid level controller.

[0010] A method for retrofitting a decomposition zone to an existing degassing vessel comprises one or more of the following steps: disconnecting a liquid sulfur supply stream from an inlet of the degassing vessel; attaching a first end of a hydrogen sulfide-rich stream to the inlet of the degassing vessel; attaching a second end of the hydrogen sulfide-rich stream to a vessel structure; attaching the inlet of the vessel structure to the liquid sulfur supply stream; disconnecting an existing liquid level controller from the degassing vessel; attaching a level suppressor of the construction disclosed herein to the degassing vessel; and attaching the level suppressor to the existing liquid level controller or a second liquid level controller.

[0011] Although 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 can be modified in many ways without departing from the spirit and scope of the claims as set forth herein. Therefore, the detailed description hereinafter will be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following drawings 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 drawings, in which:

[0013] Figure 1 A process flow diagram of a degassing vessel configured for degassing liquid sulfur is shown.

[0014] Figure 2 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0015] Figure 3 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0016] Figure 4 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0017] Figure 5 , Figure 6 and Figure 7 Respectively illustrated and Figure 1 , Figure 3 and Figure 4 The liquid sulfur degassing configuration and operation are similar to the liquid sulfur degassing configuration and operation, except that no liquid distributor is used and the level controller is directly connected to the degassing vessel.

[0018] Figure 8 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0019] Fig. 9 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0020] Fig.10 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0021] Fig.11 Another process flow diagram of a degassing vessel configured for degassing liquid sulfur is illustrated.

[0022] Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention. DETAILED DESCRIPTION

[0023] It should be understood at the outset that, although illustrative implementations of one or more embodiments are provided below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or existing. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims together with the full scope of their equivalents. Therefore, although multiple embodiments are disclosed, some 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 can be modified in many ways without departing from the spirit and scope of the claims as set forth herein. Therefore, the detailed description hereinafter will be regarded as illustrative and non-restrictive in nature.

[0024] Although the following terms are believed to be well understood by those of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the presently disclosed subject matter belongs.

[0025] As utilized herein, the "upper portion" of a contact area or vessel refers to the top 1 / 3 of the height of that area or vessel.

[0026] As utilized herein, the "middle portion" of a contact area or vessel is the middle 1 / 3 of the height of that area or vessel.

[0027] As utilized herein, the "lower portion" of a contact area or vessel refers to the lower 1 / 3 of the height of that area or vessel.

[0028] As utilized herein, "flow" includes a composition flowing within a physical structure of a pipe, a conduit, or both. Pipe, tube, and conduit are terms that may be used interchangeably.

[0029] In general, a stream comprising liquid sulfur as used herein also comprises impurities (e.g., polysulfides and hydrogen sulfide). The main technology for removing hydrogen sulfide (i.e., degassing the liquid sulfur) involves contacting the liquid sulfur in a degassing vessel with a stripping gas, wherein the liquid sulfur and the stripping gas undergo a countercurrent flow in the degassing vessel. It has been found that the stripping gas causes a layer of foam to form on the surface of the liquid sulfur, and the foam can affect the liquid level measurement of some devices, and therefore can affect the control of the liquid level in the degassing vessel. When foaming caused by the stripping gas occurs, there is a need to address the liquid level control.

[0030] Figure 1-11An embodiment of a degassing vessel 100 configured for degassing of liquid sulfur is illustrated. In general, arrow A indicates the direction of liquid flow in the degassing vessel 100 , and arrow B indicates the direction of gas flow in the degassing vessel 100 .

[0031] Now refer to Figure 1 Degassing vessel 100 is described; however, it is contemplated that Figure 2-11 Like numbers in FIG. 1 represent like features for the degassing vessel 100 in those figures, unless otherwise specified herein.

[0032] The degassing vessel 100 may be made of any suitable material, such as carbon steel or other material that is inert to the stripping gas, liquid sulfur, polysulfides, hydrogen sulfide gas, or combinations thereof.

[0033] The degassing vessel 100 is fluidly connected to a first conduit 102 and a second conduit 104. The degassing vessel 100 is configured to receive a first stream (e.g., a liquid sulfur supply stream) via the first conduit 102 and a second stream (e.g., a stripping gas supply stream) via the second conduit 104. The first stream in the first conduit 102 may contain liquid sulfur, polysulfides, and hydrogen sulfide, and the second stream in the second conduit 104 may contain stripping gas. The degassing vessel 100 includes a contacting area 106, which is configured to contact the first stream received via the conduit 102 and the second stream received via the conduit 104. The degassing vessel 100 is also configured to produce a top stream in a conduit 108 containing stripping gas and hydrogen sulfide, and a bottom stream in a conduit 110 containing degassed liquid sulfur. The degassing vessel 100 may also include a liquid level control system 120, which is configured to control the liquid sulfur level in the degassing vessel 100.

[0034] As discussed above, a first stream comprising liquid sulfur (comprising polysulfides and hydrogen sulfide) may flow into the degassing vessel 100 via conduit 102. The liquid may flow downward in the degassing vessel 100 in the direction of arrow A (optionally through a liquid distributor 103) to a contacting zone 106. A stripping gas may flow into the degassing vessel 100 via conduit 104. The gas may flow through a gas distributor 105 and flow upward in the degassing vessel 100 in the direction of arrow B to the contacting zone 106. In the contacting zone 106, the stripping gas flows upward in the direction of arrow B, and the liquid sulfur flows downward in the direction of arrow A (i.e., countercurrent flow of the liquid and gas in the degassing vessel 100), so that the liquid and gas contact each other. The contacting zone 106 may include structured packing to increase the contact time and / or contact surface area between the liquid and the gas, so as to increase the degassing efficiency. Examples of structured packing are described in U.S. Patent No. 8,663,596, which is incorporated herein by reference in its entirety.

[0035] Polysulfides and hydrogen sulfide dissolved in the liquid sulfur can be removed from the liquid by contacting the liquid with a stripping gas in the degassing vessel 100. That is, the contact of the liquid and the stripping gas under the conditions contemplated herein converts the polysulfides into hydrogen sulfide, and the converted hydrogen sulfide is transferred from the liquid sulfur to the stripping gas together with the hydrogen sulfide originally present in the liquid sulfur. Without being limited by theory, it has been demonstrated that the oxygen-containing stripping gas can oxidize the polysulfides and hydrogen sulfide present in the first stream to form SO2 and / or elemental sulfur and strip the dissolved hydrogen sulfide from the liquid sulfur. The stripping gas containing the removed hydrogen sulfide can flow upward from the contact area 106 through the degassing vessel 100 in the direction of arrow B and leave the degassing vessel 100 via the top stream contained in the conduit 108. The degassed liquid sulfur containing reduced amounts of polysulfides and hydrogen sulfide flows downward from the contact area 106 through the degassing vessel 100 and leaves the degassing vessel 100 via the bottom stream contained in the conduit 110. The bottoms stream comprising degassed liquid sulfur may include less than about 10 parts per million by weight (ppmw) combined polysulfide and dissolved hydrogen sulfide gases, based on the total weight of the components in the bottoms stream.

[0036] A supply conduit 102 containing a first stream of liquid sulfur (containing polysulfides and dissolved hydrogen sulfide) may be positioned at the top of the degassing vessel 100; however, alternative positioning of the conduit 102 may be used, as long as the location of the conduit 102 is located at a height above the top of the contacting area 106 on the degassing vessel 100. The first stream may be pumped into the degassing vessel 100 through the conduit 102 from any suitable source of liquid sulfur. For example, the first stream may be obtained from a Claus sulfur recovery plant, such as from a sulfur tank 700 in a Claus plant. The first stream may be heated or cooled to a temperature range of from about 121° C. to about 146.2° C. (about 250° F. to about 295° F.), or about 129.4° C. to about 140.6° C. (about 265° F. to about 285° F.) prior to introduction into the degassing vessel 100. The flow of the first stream in the conduit 102 may be controlled using a liquid level controller 601 to maintain the liquid sulfur level in the sulfur tank 700.

[0037] The stripping gas conduit 104 containing the second stream of stripping gas can be positioned at the bottom of the degassing vessel 100; however, alternative positioning of the conduit 104 can be used, as long as the position of the conduit 104 is located at a height below the bottom of the contact area 106 on the degassing vessel 100. The stripping gas in the second stream can be an oxygen-containing gas, such as air, oxygen-enriched air, oxygen mixed with any suitable inert gas (e.g., nitrogen and / or carbon dioxide), nitrogen, carbon dioxide, steam, natural gas, Claus tail gas, or a combination thereof. In one aspect, the air does not need to be dried before being used as a stripping gas. In one aspect, the stripping gas can have a low concentration of hydrogen sulfide, for example, less than 100 ppmv of hydrogen sulfide based on the total volume of the stripping gas. In general, the stripping gas can be provided by any suitable source. In one aspect, the stripping gas can be compressed using a blower or any other suitable device. In one aspect, the stripping gas can include from about 15% (by volume) to about 28% (by volume) oxygen; alternatively, from about 21% (by volume) to about 28% (by volume) oxygen. In one aspect, the stripping gas in the second stream is heated to a temperature in the range of about 65.5° C. to about 148.9° C. (about 150° F. to about 300° F.) prior to being introduced into the deaeration vessel 100 via conduit 104.

[0038] The flow rate of the second stream in conduit 104 can be established based on a fixed desired rate, the flow rate of the first stream in conduit 102, the oxygen concentration in the second stream in conduit 104, or a combination thereof. Although any suitable molar ratio of the first stream to the second stream can be used, typically the ratio will range from about 10 to about 60, preferably from about 20 to about 50.

[0039] The liquid level control system 600 may be configured to sense and control the flow of liquid sulfur into the degassing vessel 100 via the first stream in the conduit 102 . Figure 1 The liquid level control system 600 shown in Figure 2-7601 is partially reproduced in . The liquid level control system 600 may include a controller 601, a first link 602, and a second link 603. The controller 601 may be embodied as a computer having a processor, a memory, and instructions stored in the memory, the instructions causing the processor to perform one or more of the functions described herein for the controller 601. The controller 601 may be electrically connected to a sensor 604 placed in the sulfur tank 700 via a link 603, and the controller 601 may be configured to measure the liquid level in the sulfur tank 700 using a signal obtained from the sensor 604, for example, via a differential pressure unit / sensor, radar technology, capacitance technology, or a combination thereof. The controller 601 is connected to a control valve 101 (placed in the conduit 102) via a link 602. The controller 601 may be configured to measure the liquid level in the sulfur tank 700, and is configured to send a signal via the link 602 to adjust the control valve 101 so as to adjust the flow of liquid sulfur to the degassing vessel 100. When the liquid level control system 600 indicates that the sensed liquid level in the sulfur tank 700 is above the target liquid level, the flow of the first stream in the conduit 102 may be increased via actuation of the control valve 101. On the other hand, when the liquid level control system 600 indicates that the sensed liquid level in the sulfur tank 700 is below the target level, the flow of the first stream in the conduit 102 may be reduced via actuation of the control valve 101.

[0040] The liquid level control system 120 may be configured to sense and control the level of liquid sulfur in the degassing vessel 100. The liquid level control system 120 may include a level suppressor 201, a first conduit 202, a second conduit 203, and a controller 204. The level suppressor 201 may be embodied as a vessel or riser that is vertically oriented and fluidly connected to the degassing vessel 100 via the first conduit 202 and the second conduit 203. In one aspect, the liquid level in the level suppressor 201 is configured to indicate the liquid level in the degassing vessel 100. The controller 204 is directly connected to the level suppressor 201 via a link 205 (electrical or pneumatic connection) and is configured to measure the liquid level in the level suppressor 201. The controller 204 is not directly connected to the degassing vessel 100.

[0041] In one aspect, the level suppressor 201 is fluidly connected to the interior 112 of the degassing vessel 100 via a first conduit 202 and a second conduit 203. The first conduit 202 is connected to the level suppressor 201 and the degassing vessel 100 and is configured such that liquid (but not foam) from the degassing vessel 100 can flow into and out of the level suppressor 201. The first conduit 202 is fluidly connected to the liquid in the contact area 106 in the degassing vessel 100. Figure 1The first conduit 202 is shown as being fluidly connected to the upper portion of the contact area 106; however, it is also contemplated that the first conduit 202 may be fluidly connected to the middle portion of the lower portion of the contact area 106. It is further contemplated that the first conduit 202 may be fluidly connected to the interior space 116 of the degassing vessel 100, which is below the contact area 106 and above the gas distributor 105. The second conduit 203 is also connected to the horizontal suppressor 201 and the degassing vessel 100. The second conduit 203 may be located on the degassing vessel 100 so that the second conduit is in fluid communication with the vapor in the interior 112 of the degassing vessel 100. The second conduit 203 is fluidly connected to the vapor space 114 in the degassing vessel 100, and the vapor space 114 does not have a liquid. In one aspect, second conduit 203 may be fluidly connected to vapor space 114 of degassing vessel 100 above the top of contacting area 106 and above liquid distributor 103 (ie, for embodiments that include liquid distributor 103).

[0042] The liquid level control system 120 may also include a controller 204 connected to the level suppressor 201. The controller 204 may be embodied as a computer having a processor, a memory, and instructions stored in the memory that cause the processor to perform one or more of the functions described herein for the controller 204. The controller 204 may be electrically coupled to (multiple) sensors 206 placed in the level suppressor 201, and the controller 204 may be configured to measure the liquid level in the level suppressor 201 using signals obtained from the (multiple) sensors 206, for example, via a differential pressure cell / sensor, radar technology, capacitive technology, or a combination thereof. Figure 1-4 and Figure 8-11 , the controller 204 is not configured to directly measure the liquid level in the degassing vessel 100. That is, the liquid level in the degassing vessel 100 is measured indirectly because the level suppressor 201 is configured to indicate the liquid level in the degassing vessel 100, and the controller 204 is configured to read the liquid level in the level suppressor 201 and analyze and calculate the liquid level in the degassing vessel 100 based on the measurement results obtained from the level suppressor 201. Alternatively, the controller 204 may be configured to analyze and calculate the liquid level in the level suppressor 201 based on the measurement results obtained from the level suppressor 201, and the controller 204 may be further configured to calculate the liquid level in the degassing vessel 100 based on relevant data previously received by and stored on the memory of the controller 204.

[0043] The controller 204 may be electrically connected to the control valve 111 located in the conduit 110 via a link 207. The controller 204 may be configured to send a signal to actuate the control valve 111 to allow liquid to flow out of the degassing vessel via the bottom flow in the conduit 110. Actuating the control valve 111 may control the liquid level in the degassing vessel 100 based on the measurements obtained from the level suppressor 201.

[0044] exist Figure 1 , the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is between the first conduit 202 and the second conduit 203 of the liquid level control system 120. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is below the liquid distributor 103. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is above the contacting area 106. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that greater than 50%, 60%, 70%, 80%, 90%, or 100% of the contacting area 106 is submerged in the liquid contained in the degassing vessel 100.

[0045] Figure 2-4 The structure and Figure 1 Same as shown in , except that the polysulfide decomposition catalyst is added in various configurations.

[0046] Figure 2 The polysulfide decomposition catalyst 301 is shown included in a catalyst bed 302 in a polysulfide decomposition zone 300 in the degassing vessel 100. The catalyst bed 302 is generally located within the degassing vessel 100 above the contact zone 106. A first stream of vaporized liquid sulfur enters the degassing vessel 100 via the conduit 102 and first contacts the decomposition catalyst 301 in the annular catalyst bed 302 of the decomposition zone 300, which is configured to decompose (or dissociate) polysulfides into hydrogen sulfide and sulfur. As the liquid sulfur passes downwardly through the catalyst bed 302 in the direction of arrow A, the liquid sulfur is enriched in hydrogen sulfide. The hydrogen sulfide-enriched liquid sulfur then flows into the contact zone 106, which is configured as for Figure 1 As described. Figure 2 In the configuration of FIG. 1 , when in a single degassing vessel 100, the decomposition zone 300 and the contact zone 106 are physically separated, for example, by an inner space 305. Fluidization of the decomposition catalyst 301 in the degassing vessel 100 is avoided due to the central opening 303 in the annular catalyst bed 302, because the stripping gas rich in hydrogen sulfide can preferentially pass through the central opening 303 of the annular catalyst bed 302 in the direction of arrow C.

[0047] exist Figure 2 , it can be seen that the first conduit 202 of the liquid level control system 120 is fluidly connected to the liquid in the contacting area 106 in the degassing vessel 100. Figure 2 The first conduit 202 is shown as being fluidly connected to an upper portion of the contact area 106; however, it is also contemplated that the first conduit 202 may be fluidly connected to a middle portion or a lower portion of the contact area 106. It is further contemplated that the first conduit 202 may be fluidly connected to an interior space 116 of the degassing vessel 100, the interior space 116 being below the contact area 106 and above the gas distributor 105.

[0048] exist Figure 2 It can also be seen in FIG. 1 that the second conduit 203 is fluidly connected to the vapor space 304 of the degassing vessel 100 , which is above the catalyst bed 302 and above the liquid distributor 103 .

[0049] exist Figure 2 , the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is between the first conduit 202 and the second conduit 203 of the liquid level control system 120. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is below the liquid distributor 103. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is above the contacting area 106 and above the decomposition catalyst 301 in the catalyst bed 302. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that greater than 50%, 60%, 70%, 80%, 90%, or 100% of the catalyst bed 302 is submerged in the liquid.

[0050] Figure 3 The polysulfide decomposition catalyst 301 is shown included in a catalyst bed 302 in a polysulfide decomposition region 400 attached to the side 130 of the degassing vessel 100. The decomposition region 400 may be embodied as a vessel structure 401 having the decomposition catalyst 301 disposed therein. The vessel structure 401 may be made of the same material as the degassing vessel 100 and attached to the side 130 of the degassing vessel 100 by means known in the art, such as welding. The internal volume of the vessel structure 401 may be less than 50%, 40%, 30%, 20%, 10%, or 5% (by volume) of the total internal volume of the degassing vessel 100. Instead of directly supplying the degassing vessel 100 (as for Figure 1 and Figure 21 ), a conduit 102 containing a first stream is connected to a vessel structure 401 and is configured to flow liquid sulfur, polysulfides, and hydrogen sulfide to a decomposition region 400 contained in the vessel structure 401. The decomposition region 400 (and the vessel structure 401) may be located on an upper portion of the degassing vessel 100 such that liquid sulfur rich in hydrogen sulfide exiting the decomposition region 400 flows into the degassing vessel 100 via an outlet 402 of the vessel structure 401 at a location on the side 130 of the degassing vessel 100 above the liquid distributor 103. The liquid sulfur rich in hydrogen sulfide then flows downwardly in the direction of arrow A into a contact region 106, which is configured as for Figure 1 Just as described.

[0051] exist Figure 3 , it can be seen that the first conduit 202 of the liquid level control system 120 is fluidly connected to the liquid in the contacting area 106 in the degassing vessel 100. Figure 3 The first conduit 202 is shown as being fluidly connected to an upper portion of the contact area 106; however, it is also contemplated that the first conduit 202 may be fluidly connected to a middle portion or a lower portion of the contact area 106. It is further contemplated that the first conduit 202 may be fluidly connected to an interior space 116 of the degassing vessel 100, the interior space 116 being below the contact area 106 and above the gas distributor 105.

[0052] exist Figure 3 It can also be seen that the second conduit 203 is fluidly connected to the vapor space 306 of the deaerator vessel 100, which is above the liquid distributor 103, above the contact area 106, at a height above the catalyst bed 302, above the liquid level of liquid sulfur in the deaerator vessel 100, or a combination thereof.

[0053] exist Figure 3, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is between the first conduit 202 and the second conduit 203 of the liquid level control system 120. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the level control system 120 such that the liquid level is below the liquid distributor 103. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is above the contact area 106. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that greater than 50%, 60%, 70%, 80%, 90% or 100% of the contact area 106 is immersed in liquid. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level in the degassing vessel 100 is below the outlet 402 of the vessel structure 401 of the decomposition zone 400. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is above the outlet 402 of the vessel structure 401. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is at a height in the degassing vessel that is above the height of the catalyst bed 302 (as measured relative to the degassing vessel 100).

[0054] Figure 4 The polysulfide decomposition catalyst 301 is shown included in a catalyst bed 302 in a polysulfide decomposition zone 510, which is contained in a vessel structure 500, which is separate from and upstream of the degassing vessel 100. A conduit 102 is connected to the vessel structure 500. A first stream containing liquid sulfur, polysulfides, and hydrogen sulfide flows into the vessel structure 500 via the conduit 102. The catalyst bed 302 in the vessel structure 500 can be a fixed bed of decomposition catalyst 301. The conduit 501 is connected to the vessel structure 500, and liquid sulfur rich in hydrogen sulfide flows from the vessel structure 500 in the conduit 501. The conduit 501 is connected to the degassing vessel 100 and is configured to introduce liquid sulfur rich in hydrogen sulfide into the interior 112 of the degassing vessel 100 at a point above the liquid distributor 103. The conduit 501 may extend into the interior 112 of the degassing vessel and be configured to be directly connected to the liquid distributor 103. The angle and profile of the conduit 501 in the interior 112 of the degassing vessel 100 may be any angle or profile suitable for extending outside the degassing vessel 100 such that one end 501a of the conduit 501 is connected to the vessel structure 500 located outside the degassing vessel 100 and the opposite end 501b is connected to the liquid distributor 103 in the interior 112 of the degassing vessel 100.

[0055] exist Figure 4 , it can be seen that the first conduit 202 of the liquid level control system 120 is fluidly connected to the liquid in the contacting area 106 in the degassing vessel 100. Figure 4 The first conduit 202 is shown as being fluidly connected to an upper portion of the contact area 106; however, it is also contemplated that the first conduit 202 may be fluidly connected to a middle portion or a lower portion of the contact area 106. It is further contemplated that the first conduit 202 may be fluidly connected to an interior space 116 of the degassing vessel 100, the interior space 116 being below the contact area 106 and above the gas distributor 105.

[0056] exist Figure 4 It can also be seen in FIG. 2 that the second conduit 203 is fluidly connected to the vapor space 306 of the degassing vessel 100 , at a height above the liquid distributor 103 , above the contacting area 106 , above the liquid level of the liquid sulfur in the degassing vessel 100 .

[0057] exist Figure 4 501. In the embodiment of the present invention, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 so that the liquid level is between the first conduit 202 and the second conduit 203 of the liquid level control system 120. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 so that the liquid level is below the liquid distributor 103. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 so that the liquid level is above the contact area 106. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 so that greater than 50%, 60%, 70%, 80%, 90% or 100% of the contact area 106 is immersed in liquid. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 so that the liquid level is below the conduit 501. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the liquid level control system 120 such that the liquid level is above the conduit 501 .

[0058] Figure 5 , Figure 6 and Figure 7 Respectively illustrated and Figure 1 , Figure 3 and Figure 4 The liquid sulfur degassing configuration and operation are similar to the liquid sulfur degassing configuration and operation, except that no liquid distributor is used and the liquid level controller 204 is directly connected to the degassing vessel 100. Figure 5 , Figure 6 and Figure 7In one aspect, the controller 204 can be configured to measure the liquid level in the degassing vessel 100 using signals obtained from the sensor(s) 206 via capacitive technology. In one aspect, the sensor(s) 206 can be placed in a manner directed to Figure 5 , Figure 6 and Figure 7 In the top head of the degassing vessel 100.

[0059] exist Figure 5-7 , the controller 204 is configured to measure the liquid sulfur level in the degassing vessel 100 based on a signal obtained from the sensor 206 via the link 205. The controller 204 may then determine the liquid sulfur level in the degassing vessel 100 based on the measurement results and send a signal via the link 207 to adjust the control valve 111 in the conduit 110 if necessary so as to adjust the liquid level in the degassing vessel 100.

[0060] exist Figure 5-7 In the embodiment of the present invention, the liquid sulfur level in the degassing vessel 100 may be controlled by the controller 204 so that the liquid level is below the point at which the liquid sulfur is introduced into the degassing vessel 100. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the controller 204 so that the liquid level is above the contacting area 106. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 may be controlled by the controller 204 so that the liquid level is above the point at which the liquid sulfur is introduced into the degassing vessel 100. Additionally or alternatively, in Figure 7 In the embodiment of the present invention, the liquid sulfur level in the degassing vessel 100 can be controlled by the controller 204 so that the liquid level is below the conduit 501. Additionally or alternatively, the liquid sulfur level in the degassing vessel 100 can be controlled by the controller 204 so that the liquid level is above the point where the liquid sulfur conduit 501 is introduced into the degassing vessel 100.

[0061] exist Figure 7 In the embodiment, end 501a of conduit 501 is connected to vessel structure 500; however, opposite end 501b is not connected to the liquid distributor because Figure 7 The construction in does not include a liquid distributor. Figure 7 Aspects include configurations of the conduit 501 wherein the opposite end 501 b is directly connected to the side 130 of the degassing vessel 100 , or wherein the opposite end 501 b extends into the interior 112 of the degassing vessel 100 .

[0062] It is contemplated that embodiments within the scope of the present disclosure may include Figure 1-4 The liquid level control system 120 may not have Figure 5-7 It is also contemplated that embodiments may include the following: Figure 1-4 The liquid distributor 103 shown in FIG. Figure 5-7Controller 204 is shown connected directly to degassing vessel 100 (ie, without using level suppressor 201).

[0063] Figure 8-11 The diagram is similar to Figure 1-4 The manner of the degassing vessel illustrated in FIG. 1 is an additional embodiment of a degassing vessel configured for degassing liquid sulfur.

[0064] exist Figure 8-11 1, a control valve 101 disposed in the conduit 102 is also connected to the controller 204 and is part of the liquid level control system 120. The flow of the first stream in the conduit 102 can be controlled using the liquid level control system 120 to maintain the contact area 106 in a submerged configuration. When the liquid level control system 120 indicates that the contact area 106 is in or near a configuration that is not fully submerged, the flow of the first stream in the conduit 102 can be increased. The flow is also controlled to provide a preselected residence time in the degassing vessel 100 to achieve a desired level of polysulfide removal from the first stream, and / or to achieve a desired level of hydrogen sulfide gas removal from the first stream. The controller 204 can be electrically connected to the first control valve 101 via a link 208, and / or electrically connected to the second control valve 111 via a link 207. The controller 204 may be configured to send a signal to actuate the control valve 101 via the link 208 and / or the control valve 111 via the link 207 to allow liquid to flow into the degassing vessel via the conduit 102 or to allow liquid to flow out of the degassing vessel via the conduit 110. Actuating the control valve 101 and / or the control valve 111 may control the liquid level in the degassing vessel 100 based on the measurement results obtained from the level suppressor 201.

[0065] Figure 8-11 Other aspects of degassing vessels in Figure 1-4 Same as described.

[0066] Retrofitting to the decomposition region of an existing degassing vessel 100 is also contemplated within the present disclosure. Figure 1 as well as Figure 3 , Figure 6 or Fig.10, modifying the degassing vessel 100 to include a decomposition zone may include: disconnecting the first conduit 102 from the inlet of the degassing vessel 100; attaching the outlet of a vessel structure 401 configured to hold a decomposition catalyst to the inlet of the degassing vessel 100; and attaching the inlet of the vessel structure 401 to the first conduit 102. Modifications in this aspect do not change the configuration of the degassing vessel 100. The modification may further include placing a decomposition catalyst 301 in the vessel structure 401. The decomposition catalyst 301 may be an embodiment and aspect described herein, and the decomposition catalyst 301 may be in a catalyst bed 302, the catalyst bed 302 may be configured to hold the decomposition catalyst 301 in place to minimize mechanical damage to the catalyst particles, or the vessel structure 401 may be configured to hold the decomposition catalyst 301 in place to minimize mechanical damage to the catalyst particles. Retrofitting may also include detaching the existing liquid level controller 204 from the degassing vessel 100, attaching a level suppressor 201 of the construction disclosed herein to the degassing vessel 100 (eg, via conduits 202 and 203), and attaching the level suppressor 201 to the existing liquid level controller 204 or a second liquid level controller.

[0067] Retrofitting to the decomposition region of an existing degassing vessel 100 is also contemplated within the present disclosure. Figure 1 as well as Figure 4 , Figure 7 or Fig.11 , modifying the degassing vessel 100 to include a decomposition zone may include: disconnecting the first conduit 102 from the inlet of the degassing vessel 100; attaching the first end of the hydrogen sulfide-rich conduit 501 to the inlet of the degassing vessel 100; attaching the second end of the hydrogen sulfide-rich conduit 501 to the vessel structure 500; and attaching the inlet of the vessel structure 500 to the first conduit 102. Modifications in this aspect do not change the configuration of the degassing vessel 100.

[0068] The modification may further include placing the decomposition catalyst 301 in the vessel structure 500. The decomposition catalyst 301 may be an embodiment and aspect described herein, and the decomposition catalyst 301 may be in a catalyst bed 302, the catalyst bed 302 is configured to hold the decomposition catalyst 301 in place to minimize mechanical damage to the catalyst particles, or the vessel structure 500 may be configured to hold the decomposition catalyst 301 in place to minimize mechanical damage to the catalyst particles. The modification may also include disconnecting the existing liquid level controller 204 from the degassing vessel 100, attaching the level suppressor 201 of the construction disclosed herein to the degassing vessel 100 (e.g., via conduits 202 and 203), and attaching the level suppressor 201 to the existing liquid level controller 204 or a second liquid level controller.

[0069] Figure 1-11Each of the configurations in solves the problem of inaccurate liquid level control when foam is present in the degassing vessel 100 .

[0070] for Figure 2-4 , Figure 6-7 and Figure 9-11 For purposes of the present invention, any catalyst configured to catalyze the decomposition of polysulfides in liquid sulfur to hydrogen sulfide may be used as the decomposition catalyst. Suitable catalysts include particulate Claus or Claus-type catalyst materials, and especially porous alumina or metal oxides supported on alumina, unpromoted or promoted activated alumina and titania catalysts as well as alumina-titania composites, all of which may be structured or coated onto a metal or ceramic support to enhance the decomposition of polysulfides to hydrogen sulfide and to allow hydrogen sulfide to be stripped from the sulfur using a stripping gas at typically low to moderate pressures.

[0071] Figure 2-4 , Figure 6-7 and Figure 9-11 Each of the configurations utilizes a decomposition catalyst that can dissociate polysulfides into hydrogen sulfide and sulfur, which are more easily removed from the liquid sulfur using a stripping gas.

[0072] Figure 2-4 , Figure 6-7 and Figure 9-11 Each of the configurations in requires lower stripping gas flows, thus saving operating costs. This is because the catalytic decomposition of polysulfides into hydrogen sulfide and sulfur allows for lower operating pressures, which results in stripping being the primary mode of hydrogen sulfide removal rather than oxidation (oxidation as a means for hydrogen sulfide removal is supported by higher pressures than stripping).

[0073] Figure 2-4 , Figure 6-7 and Figure 9-11 Each of the configurations in can catalytically decompose polysulfides into hydrogen sulfide and sulfur without mechanical damage to the catalyst.

[0074] Figure 1-11The degassing vessel 100 in the can be operated under any suitable conditions. In one aspect, the degassing vessel 100 can be operated at a pressure range of about 0.03 Mpag to about 1.38 Mpag (about 5 psig to about 200 psig); the pressure range is alternatively about 0.03 Mpag to about 0.35 Mpag (about 5 psig to about 50 psig); alternatively about 0.20 Mpag to about 0.83 Mpag (about 30 psig to about 120 psig); alternatively about 0.27 Mpag to about 0.55 Mpag (about 40 psig to about 80 psig). The pressure of the degassing vessel 100 can be controlled by adjusting the flow rate of the top flow in the conduit 108 via a flow control system having a controller for the hardware described for other controllers 204 and 601 herein. In one aspect, the deaeration vessel 100 is operable such that the residence time of the liquid sulfur is in the range of 1 second to 2 hours.

[0075] Figure 1 , Figure 5 and Figure 8 Conditions in the degassing vessel 100 may also include elevated pressure (eg, about 0.20 MPag to about 1.38 MPag (about 30 psig to about 200 psig)) which promotes liquid phase oxidation of polysulfides and hydrogen sulfide by oxygen provided by the stripping gas and dissolved in the sulfur.

[0076] Figure 2-4 , Figure 6-7 and Figure 9-11 The conditions in the degassing vessel 100 include a lower operating pressure (e.g., about 0.03 MPa to about 0.20 MPa (about 5 psig to about 30 psig)) because the catalytic decomposition of polysulfides to hydrogen sulfide allows for a lower operating pressure at which the hydrogen sulfide can be stripped from the hydrogen sulfide-rich liquid sulfur. The lower operating pressure reduces the potential for corrosion of the degassing equipment by lowering the water dew point temperature.

[0077] The catalytic decomposition of polysulfides may also allow shorter residence times and smaller degassing equipment.

[0078] Although various embodiments have been shown and described, modifications thereof may be made by those skilled in the art without departing from the spirit and teachings of the present disclosure. The embodiments described herein are exemplary only and are not intended to be limiting. Many variations and modifications of the subject matter disclosed herein are possible and are within the scope of the present disclosure. Where numerical ranges or limitations are explicitly stated, such explicit ranges or limitations should be understood to include iterative ranges or limitations of similar magnitudes falling within the explicitly stated ranges or limitations (e.g., from about 1 to about 10 includes 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a lower limit R is disclosed, L and upper limit R U When a numerical range is specified, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R = R L +k*(R U -R L ), wherein k is a variable that increases by 1% in the range from 1% to 100%, that is, k is 1%, 2%, 3%, 4%, 5%, ... 50%, 51%, 52%, 90%, 95%, 96%, 97%, 98%, 99% or 100%. In addition, any numerical range defined by two R numbers (as defined above) is also specifically disclosed. The use of the term "optionally" with respect to any element of the claim is intended to mean that the subject element is required, or alternatively, is not required. Both alternatives are intended to be within the scope of the claim. The use of broader terms (such as including, comprising, having, etc.) should be understood to provide support for narrower terms (such as consisting of, substantially consisting of, roughly consisting of, etc.).

[0079] Therefore, the scope of protection is not limited by the description set out above, but only by the following claims, which scope includes all equivalents of the subject matter of the claims. Each claim is incorporated into the specification as an embodiment of the present disclosure. Therefore, the claims are further descriptions and are supplementary to the embodiments of the present disclosure. The discussion of references is not an admission that they are prior art to the present disclosure, especially any references that may have a publication date after the priority date of this application. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference to the extent that they provide exemplary, procedural or other details that supplement the contents set forth herein.

[0080] Additional description

[0081] The specific embodiments disclosed above are illustrative only, as the present disclosure can be modified and practiced in different but equivalent ways that are obvious to those skilled in the art who benefit from the teachings herein. In addition, it is not intended to limit the details of construction or design shown herein, except as described in the claims below. Therefore, it is obvious that the specific illustrative embodiments disclosed above can be changed or modified, and all such changes are considered to be within the scope and spirit of the present disclosure. Alternative embodiments resulting from the combination, integration and / or omission of the features of (multiple) embodiments are also within the scope of the present disclosure. Although systems and methods are described in broader terms of "having", "comprising", "containing" or "including" a variety of components or steps, compositions and methods may also be "essentially composed of a variety of components and steps" or "composed of a variety of components and steps". The use of the term "optionally" with respect to any element of a claim means that the element is required, or alternatively, the element is not required, and both alternatives are within the scope of the claim.

[0082] The above disclosed numbers and ranges can vary by a certain amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, each range of values ​​disclosed herein (in the form of "from about a to about b", or equivalently "from approximately a to b", or equivalently, "from approximately ab") will be understood to be each number and range contained in a wider range of values. In addition, unless the patentee clearly and clearly defines otherwise, the terms in the claims have their ordinary, common meanings. In addition, the indefinite article "one" or "an" used in the claims is defined herein as meaning one or more than one of the elements it introduces. If there is any conflict in the use of a word or term in this specification and one or more patents or other documents, the definition consistent with this specification should be adopted.

[0083] Various systems and processes have been described herein, and specific embodiments or aspects may include, but are not limited to:

[0084] Embodiments disclosed herein include:

[0085] A: A liquid sulfur degassing system, comprising: a degassing vessel, the degassing vessel being configured to receive liquid sulfur and a stripping gas therein, and being configured to contact the liquid sulfur with the stripping gas so as to produce a bottom stream comprising degassed liquid sulfur and a top stream comprising the stripping gas enriched in hydrogen sulfide; and a liquid level controller, the liquid level controller being directly or indirectly connected to the degassing vessel and configured to: determine the level of liquid sulfur in the degassing vessel; and control the level of liquid sulfur in the degassing vessel based on the level of liquid sulfur determined for the degassing vessel.

[0086] B. A liquid sulfur degassing system comprising: a degassing vessel configured to receive liquid sulfur and a stripping gas therein, and configured to contact the liquid sulfur with the stripping gas so as to produce a bottom stream comprising degassed liquid sulfur and a top stream comprising a stripping gas enriched in hydrogen sulfide; a level suppressor fluidly connected to the degassing vessel; and a liquid level controller connected to the level suppressor and configured to: measure a first level of liquid sulfur in the level suppressor; and control the level of liquid sulfur in the degassing vessel based on the first level measured for the level suppressor.

[0087] C: A method of treating liquid sulfur containing polysulfides and hydrogen sulfide, comprising: contacting the liquid sulfur with a stripping gas in a contacting zone of a degassing vessel; determining the level of liquid sulfur in the degassing vessel; and controlling the level of liquid sulfur in the degassing vessel based on the determining step.

[0088] D: A method for treating liquid sulfur containing polysulfides and hydrogen sulfide, comprising: contacting the liquid sulfur with a stripping gas in a contact area of ​​a degassing vessel; and measuring a first level of the liquid sulfur in a level suppressor, which is fluidly connected to the degassing vessel and configured to indicate a second liquid level of the liquid sulfur in the degassing vessel; and controlling the second level of the liquid sulfur in the degassing vessel based on the measuring step.

[0089] E: A method for retrofitting a decomposition zone to an existing degassing vessel comprises one or more of the following steps: disconnecting a liquid sulfur supply conduit from an inlet of the degassing vessel; attaching an outlet of a vessel structure configured to hold a decomposition catalyst to the inlet of the degassing vessel; attaching the inlet of the vessel structure to the liquid sulfur supply conduit; placing a decomposition catalyst in the vessel structure; disconnecting an existing liquid level controller from the degassing vessel; attaching a level suppressor of the construction disclosed herein to the degassing vessel; and attaching the level suppressor to the existing liquid level controller or a second liquid level controller.

[0090] F: A method for retrofitting a decomposition zone to an existing degassing vessel comprises one or more of the following steps: disconnecting a liquid sulfur supply conduit from the inlet of the degassing vessel; attaching a first end of a hydrogen sulfide-rich conduit to the inlet of the degassing vessel; attaching a second end of the hydrogen sulfide-rich conduit to a vessel structure; attaching the inlet of the vessel structure to the liquid sulfur supply conduit; disconnecting an existing liquid level controller from the degassing vessel; attaching a level suppressor of the construction disclosed herein to the degassing vessel; and attaching the level suppressor to the existing liquid level controller or a second liquid level controller.

[0091] G: Each of embodiments A, B, C, D, E, and F may have one or more of the following additional elements: Element 1: wherein controlling the level of liquid sulfur is not affected by foam in the degassing vessel. Element 2: wherein controlling the level includes actuating a control valve located in a second stream comprising degassed liquid sulfur. Element 3: further comprising contacting the liquid sulfur with a decomposition catalyst prior to contacting the liquid sulfur with the stripping gas. Element 4: further comprising contacting the liquid sulfur with a decomposition catalyst prior to contacting the liquid sulfur with the stripping gas. Element 5: wherein the decomposition catalyst is in a catalyst bed. Element 6: wherein the catalyst bed is placed in the degassing vessel and above the contacting area. Element 7: wherein the catalyst bed is an annular catalyst bed. Element 8: wherein the catalyst bed is attached to the upper side of the degassing vessel. Element 9: wherein the catalyst bed is in a second vessel, the method further comprising receiving a liquid sulfur supply stream into the second vessel, and flowing a liquid sulfur stream rich in hydrogen sulfide from the second vessel to the degassing vessel. Element 10: wherein determining the level of liquid sulfur in the degassing vessel comprises measuring a second level of liquid sulfur in a level suppressor fluidly connected to the degassing vessel, and determining the level of liquid sulfur in the degassing vessel based on the second level measured in the level suppressor. Element 11: wherein the level suppressor is fluidly connected to the degassing vessel by a first conduit and a second conduit, wherein the first conduit is in fluid communication with the liquid sulfur in the degassing vessel, and wherein the second conduit is in fluid communication with a vapor space of the degassing vessel.

[0092] H: Each of embodiments A, B, C, D, E, and F may have one or more of the following additional elements: Element 1: wherein controlling the second level of liquid sulfur is not affected by foam in the degassing vessel. Element 2: wherein controlling the second level comprises actuating a first control valve located in a first stream comprising liquid sulfur, polysulfides, and hydrogen sulfide; or actuating a second control valve located in a second stream comprising degassed liquid sulfur. Element 3: further comprising contacting the liquid sulfur with a decomposition catalyst before contacting the liquid sulfur with the stripping gas. Element 4: further comprising contacting the liquid sulfur with a decomposition catalyst before contacting the liquid sulfur with the stripping gas. Element 5: wherein the decomposition catalyst is in a catalyst bed. Element 6: wherein the catalyst bed is placed in the degassing vessel and above the contacting zone. Element 7: wherein the catalyst bed is an annular catalyst bed. Element 8: wherein the catalyst bed is attached to the upper side of the degassing vessel. Element 9: Wherein the catalyst bed is in a second vessel, the method further comprising receiving a liquid sulfur feed stream into the second vessel, and flowing the hydrogen sulfide rich liquid sulfur stream from the second vessel to the degassing vessel.

[0093] I: Each of embodiments A, B, C, D, E, and F may have one or more of the following additional elements: Element 1: further includes a level suppressor fluidly connected to the degassing vessel, wherein the liquid level controller is configured to determine the level of liquid sulfur in the degassing vessel by measuring a second level of liquid sulfur in the level suppressor. Element 2: wherein the determination and control by the liquid level controller are not affected by foam in the degassing vessel. Element 3: further includes: a control valve coupled to the degassing vessel; wherein the liquid level controller is configured to: actuate the control valve to allow the flow of degassed liquid sulfur from the degassing vessel. Element 4: further includes: a first conduit configured to fluidly couple the degassing vessel to the level suppressor; and a second conduit configured to fluidly couple the degassing vessel to the level suppressor, wherein the first conduit is in fluid communication with the liquid sulfur in the degassing vessel, wherein the second conduit is in fluid communication with the vapor space of the degassing vessel. Element 5: further includes a decomposition catalyst placed in the degassing vessel. Element 6: wherein the decomposition catalyst is in a catalyst bed which is placed above the contacting area of ​​the degassing vessel. Element 7: wherein the catalyst bed is an annular catalyst bed. Element 8: wherein the decomposition catalyst is in a catalyst bed which is attached to the upper side of the degassing vessel. Element 9: wherein the decomposition catalyst is in a catalyst bed which is in a second vessel.

[0094] J: Each of embodiments A, B, C, D, E, and F may have one or more of the following additional elements: Element 1: wherein the measurement and control by the liquid level controller is not affected by the foam in the degassing vessel. Element 2: further includes a first control valve, the first control valve is connected to the degassing vessel, and a second control valve, the second control valve is connected to the degassing vessel, wherein the liquid level controller is configured to: actuate the first control valve to allow the flow of liquid sulfur, polysulfides, and hydrogen sulfide to the degassing vessel, or actuate the second control valve to allow the flow of degassed liquid sulfur from the degassing vessel. Element 3: further includes a first conduit, the first conduit is configured to fluidly connect the degassing vessel to the horizontal suppressor; and a second conduit, the second conduit is configured to fluidly connect the degassing vessel to the horizontal suppressor. Element 4: further includes a decomposition catalyst, the decomposition catalyst is placed in the degassing vessel. Element 5: wherein the decomposition catalyst is in a catalyst bed, the catalyst bed is placed above the contact area of ​​the degassing vessel. Element 6: wherein the catalyst bed is an annular catalyst bed. Element 7: wherein the decomposition catalyst is in a catalyst bed, the catalyst bed being attached to the upper side of the degassing vessel. Element 8: wherein the decomposition catalyst is in a catalyst bed, the catalyst bed being in a second vessel.

[0095] Although the preferred embodiments of the present invention have been shown and described, modifications thereof may be made by those skilled in the art without departing from the teachings of the present disclosure. The embodiments described herein are merely exemplary and are not intended to be restrictive. Many variations and modifications of the present invention disclosed herein are possible and are within the scope of the present invention.

[0096] Once the above disclosure is fully understood, many other modifications, equivalents and alternatives will become apparent to those skilled in the art. It is intended that the following claims be interpreted as including all such modifications, equivalents and alternatives where applicable. Therefore, the scope of protection is not limited by the description set out above, but only by the following claims, which include all equivalents of the subject matter of the claims. Each claim is incorporated into the specification as an embodiment of the present invention. Therefore, the claims are further described and are a supplement to the detailed description of the present invention. The disclosures of all patents, patent applications and publications cited herein are hereby incorporated by reference.

Claims

1. A method for treating liquid sulfur containing polysulfides and hydrogen sulfide, comprising: contacting the liquid sulfur with a stripping gas in a contacting zone of a degassing vessel; whereby foam is formed in said degassing vessel and a level of foam is present in said degassing vessel; determining the level of the liquid sulfur in the degassing vessel, wherein determining the level of the liquid sulfur in the degassing vessel comprises: measuring, by a sensor, a second level of the liquid sulfur in a level suppressor fluidly connected to the degassing vessel; and determining the level of the liquid sulfur in the degassing vessel based on the second level measured in the level suppressor; and The level of the liquid sulfur in the degassing vessel is controlled based on the step of determining the level of the liquid sulfur in the degassing vessel.

2. The method according to claim 1, wherein: The level of the liquid sulfur is controlled without being affected by foam in the degassing vessel.

3. The method according to claim 1, wherein: Controlling said levels includes: A control valve is actuated, the control valve being located in a conduit including the degassed liquid sulfur.

4. The method according to claim 1, further comprising: Prior to contacting the liquid sulfur with the stripping gas, the liquid sulfur is contacted with a decomposition catalyst.

5. The method according to claim 4, wherein: The decomposition catalyst is in a catalyst bed.

6. The method according to claim 5, wherein: The catalyst bed is placed in the degassing vessel above the contacting zone.

7. The method according to claim 6, wherein: The catalyst bed is an annular catalyst bed.

8. The method according to claim 5, wherein: The catalyst bed is attached to the upper side of the degassing vessel.

9. The method according to claim 5, wherein: The catalyst bed is in a second vessel, and the method further comprises: receiving a liquid sulfur feed stream into the second vessel; and A liquid sulfur stream rich in hydrogen sulfide is flowed from the second vessel to the degassing vessel.

10. The method according to claim 1, wherein: The horizontal suppressor is fluidly connected to the degassing vessel by a first conduit, wherein the first conduit is in fluid communication with the liquid sulfur in the degassing vessel, and a second conduit, wherein the second conduit is in fluid communication with a vapor space of the degassing vessel.

11. A liquid sulfur degassing system, comprising: a degassing vessel configured to receive liquid sulfur and a stripping gas therein and to contact the liquid sulfur with the stripping gas, thereby forming foam in the degassing vessel such that a level of foam exists in the degassing vessel to produce a bottom stream comprising degassed liquid sulfur and an overhead stream comprising the stripping gas enriched in hydrogen sulfide; a level suppressor fluidly connected to the degassing vessel and comprising a sensor; and A liquid level controller comprising a sensor configured to: measuring, by a sensor, a second level of the liquid sulfur in the level suppressor, wherein the second level is different from a level of foam present on the liquid sulfur in the degassing vessel; determining the level of the liquid sulfur in the degassing vessel; and The level of the liquid sulfur in the degassing vessel is controlled based on the level of the liquid sulfur determined for the degassing vessel.

12. The system according to claim 11, wherein: The determination and control functions performed by the liquid level controller are not affected by foam in the degassing vessel.

13. The system according to claim 11, further comprising: a first conduit configured to fluidly couple the degassing vessel to the horizontal suppressor; as well as a second conduit configured to fluidly couple the degassing vessel to the level suppressor, Wherein the first conduit is in fluid communication with the liquid sulfur in the deaeration vessel, and wherein the second conduit is in fluid communication with a vapor space of the deaeration vessel.

14. The system according to claim 11, further comprising: a control valve coupled to the degassing vessel; Wherein the liquid level controller is configured to actuate the control valve to allow flow of deaerated liquid sulfur from the deaeration vessel.

15. The system according to any of claim 11, further comprising: The decomposition catalyst is placed in the degassing vessel.

16. The system of claim 15, wherein: The decomposition catalyst is in a catalyst bed that is placed above the contacting zone of the degassing vessel.

17. The system of claim 16, wherein: The catalyst bed is an annular catalyst bed.

18. The system of claim 15, wherein: The decomposition catalyst is in a catalyst bed that is attached to the upper side of the degassing vessel.

19. The system of claim 15, wherein: The decomposition catalyst is in a catalyst bed, and the catalyst bed is in a second vessel.

20. A method for retrofitting a decomposition zone to an existing degassing vessel, comprising: disconnecting the liquid sulfur supply conduit from the inlet of the degassing vessel; attaching an outlet of a vessel structure configured to hold a decomposition catalyst to the inlet of the degassing vessel; attaching an inlet of the vessel structure to the liquid sulfur supply conduit; placing the decomposition catalyst in the vessel structure; disconnecting an existing liquid level controller from the degassing vessel; attaching a horizontal suppressor to the degassing vessel; as well as Attach the level suppressor to an existing liquid level controller or a second liquid level controller.

21. A method for retrofitting a decomposition zone to an existing degassing vessel, comprising: disconnecting the liquid sulfur supply conduit from the inlet of the degassing vessel; attaching a first end of a hydrogen sulfide-rich conduit to the inlet of the degassing vessel; attaching a second end of the hydrogen sulfide-enriched conduit to a vessel structure; as well as attaching an inlet of the vessel structure to the liquid sulfur supply conduit; disconnecting an existing liquid level controller from the degassing vessel; attaching a horizontal suppressor to the degassing vessel; as well as Attach the level suppressor to an existing liquid level controller or a second liquid level controller.

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