SETR- SUPER ENHANCED TAIL GAS RECOVERY; A TAIL GAS PROCESS WITH ADSORBENT REACTORS FOR ZERO EMISSIONS

Abstract

SETR tail gas treating process refers to an innovative process consist of the adsorbent and regeneration reactors. The SETR reactor stands for Super Enhanced Tail gas Recovery switching between adsorption and regeneration mode and the STER reactors are located after the tail gas incineration before the stack replacing any type of the caustic scrubber system. The SETR innovative process is not a sub dew point process where the bed become saturated with sulfur, instead, the SETR process are fixed bed reactors that requires heat up and cool down for the SO2 adsorption-based Claus tail gas process. The adsorption mode operates at cold temperature to adsorb the SO2. The regenerator mode operates at hot temperature to regenerate the SO2 by adding a slip stream of the H2S and air from the SRU to the SETR reactor that contains adsorbed SO2 to promote the Claus reaction. In the SETR reactors H2S to react with the adsorbed SO2 in the bed with oxygen the outlet of the hot reactor is recycled to the SRU thermal or catalytic section. The gas stream from the adsorbed cold reactor flows to the stack and it is SO2 free and zero emission is achieved.

Claims

1. A tail gas treating process for recovering the sulfur compounds and recycling back to the sulfur recovery plant located after the tail gas incineration and before the stack, it is not a sub dew point process where the bed become saturated with sulfur, instead, the SETR process are fixed bed reactors that requires heat up and cool down for the SO2 adsorption-based Claus tail gas process; The SETR reactors do not use any chemical agent or solvent and do not produce any chemical or spent waste stream. The process comprising the following 7 steps: A-step 1) The process comprises two reactors as the adsorbent and regeneration reactors operates in two cycles cold and hot mode; B-step 2) The process comprises at least the Claus catalysts containing Alumina and Titanium catalysts to initiate and to perform the Claus reaction in regeneration mode; C-step 3) The adsorbent cold reactor receives the incineration outlet combusted gas stream through a cooler to adsorb sulfur compounds as SO2, D-step 4) The regeneration hot reactor receives a slip stream of amine acid gas feed stream to the SRU and a slip stream of air from the combustion air blower to regenerate adsorbed SO2 and to initiate the Claus reaction, mode of operation switches between hot and cold at least once a day; E-step 5) The process comprises motor operating switching valves to control these reactors for switching between hot and cold mode of operation on five inlet and outlet streams; F-step 6) The outlet gas stream from the adsorbent cold reactor flows to the stack as the sulfur free stream and the outlet gas stream from the regeneration hot reactor is recycled back to the sulfur plant; G-step 7) The process comprises the incineration system replacing any type of the Caustic scrubber system to achieve SO2 emission of less than 50 ppmv, preferably less than 10 ppmv respectively.

2. The process of claim 1, wherein, the acid gas streams consist of at least one member selected from the group consisting of H2S, NH3, HCN, H2, CO, CO2, O2 COS, N2, CS2, hydrocarbons, mercaptans, sulfur vapors and steam water.

3. The process of claim 1, wherein, in any type of the sulfur plants, the SETR tail gas treating can be added after the incineration and before the stack to increase overall recovery and to reduce the SO2 emission, in such the sulfur plants can be the conventional Claus, any sub dew point processes, Claus stage plus direct oxidation and direct reduction stages, the conventional tail gas and amine treating units unit, partial enrichment tail gas treating unit, and for acid gases with low H2S concentration known as lean acid gas where direct oxidation catalyst types Selectox, Titanium or similar are used.

4. The process of claim 1, wherein the step 1 reaction furnace of the sulfur plant is equipped with one or more checker wall or choke ring or VECTORWALL.

5. The process of claim 1, wherein the cold adsorbent reactor operates at 125 C to 130 C to maximize the SO2 adsorption and the SETR regeneration reactor operates at 320 C to 400 C to maximize the SO2 regeneration and to promote the Claus reaction.

6. The process of claim 1, wherein the recycle gas from the SETR tail gas treating is injected to the reaction furnace or downstream of the first condenser.

7. The process of claim 1, wherein, the catalytic stages of the sulfur plants and the SETR reactors consists of one or more Claus catalysts including alumina catalysts, activated alumina catalysts alumina/titania catalysts, and/or titania catalysts, Iron with Zinc, Iron with Nickel, Cr, CO/MO, Mo, Mn, Co, Mg with promoter on Alumina and with any other combination or any other catalyst systems which are employed in the Claus process. The catalysts having a range of surface area, pore volume, shapes. The Claus processes within converter and subsequent converters, such as converter may be carried out at conventional reaction temperatures, ranging from about 200 C. to about 1300 C., and from about 240 C. to about 600 C., as well as over temperature ranges between these ranges, including from about 210 C. to about 480 C., and from about 950 C. to about 1250 C.

8. The process of claim 1, wherein, the SETR reactors consist of Titanium catalyst is located at the top due to oxygen presence and the alumina at the bottom, where the air stream flows to the top of the reactor.

9. The process of claim 1, wherein, the recycle gas from the SETR regeneration reactor has enough driving force or adequate pressure because the slip stream of the amine acid gas and air from the combustion air blower provides sufficient pressure to the recycle the regenerated gas stream.

10. The process of claim 1, wherein, the switching valves are 2-ways, or 3-ways type located at least on 5 streams, 3 inlet gas stream to the reactors and 2 outlet gas stream from the reactors.

11. The process of claim 1, wherein, the tail gas is further processed in the amine tail gas unit to absorb the H2S and in the regeneration section the recovered acid gas is recycled to the sulfur recovery into the reaction furnace, the absorber overhead is routed to the incineration followed by the SETR reactors.

12. The process of claim 1, wherein, the step 5 where the tail gas is sent to the conventional thermal incineration replacing any type of the caustic scrubber with the SETR reactors for achieving SO2 emission of less than 50 ppmv preferably less than 10 ppmv respectively which is equivalent to 99.99+% sulfur recovery.

13. The process of claim 1, wherein, the rate of the air, enriched air or oxygen enrichment stream is adjusted such that the mole ratio of hydrogen sulfide to sulfur dioxide in the gaseous-mixture reaction stream ranges from 1.5:1 to 10:1 in any type of sulfur recovery unit.

14. The process of claim 1, wherein, the last condenser is at least one heat exchanger or multiple heat exchangers, dual condensers or combination of thermoplate, water coolers and air coolers to achieve maximum sulfur condensation and sulfur recoveries.

15. The process of claim 1, wherein, in the reaction furnace, the hydrocarbon containing gas stream comprises one or more hydrocarbons selected from the group consisting of alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, and mixtures thereof.

16. The process of claim 1, wherein, the slip stream of the amine acid gas and slip stream of air is adequate to establish the proper reaction temperature and to promote the Claus reaction and to regenerate the maximum adsorbed SO2.

17. The process of claim 1, wherein, the combusted gas from the incineration contains SO2, N2, CO2, H2S where will be adsorbed by the catalytic bed in form of O2, SO2, S2O3 and SO4.sup.. During the regeneration SO2 and S2O3.sup. are desorbed and H2S and air is added the reactions are resulted in the Claus Equilibrium for the system.

18. The process of claim 1, wherein, the regeneration procedure accomplishes a number of chemical transformations. Most importantly, SO2 is displaced by the hot gas and sulphate and thiosulphate which they are present on the surface of the adsorbent and after an uptake cycle are reduced by H2S in the regeneration stream of the amine acid gas, in addition any oxygen which is adsorbed in the uptake cycle will be removed by reaction with H2S.

19. The process of claim 1, wherein, the SETR reactors can be added to the scheme of the patented process, May 5, 2015 (U.S. Pat. No. 9,023,309 B1) by M. Rameshni; as known as SMAX and SMAXB to achieve zero SO2 emission.

20. The process of claim 1, wherein, the SETR reactors can be added to the scheme of the patent pending of the application filed regard to SUPERSULF process (application Ser. No. 14/826,198, Aug. 14, 2015) the zero SO2 emission is achieved.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The following figures are part of the present disclosure and are included to further illustrate certain aspects of the present invention. Aspects of the invention may be understood by reference to one or more figures in combination with the detailed written description of specific embodiments presented herein. FIG. 1c represents the innovative SETR process where it can be employed to variety type of Claus as several schemes as are discussed below.

[0065] FIG. 1 consists of drawings, 1-1a, 1-1b and 1-1c and illustrates a schematic diagram embodiment of the present disclosure consisting of (1a) Claus section which includes the thermal section and 2 OR 3 catalytic stages, (1b) the incineration system that receives the tail gas stream from the last condenser directly, (1c) the innovative SETR scheme that receives the gas stream from the incineration outlet.

[0066] FIG. 2 consists of 2-2a, 1-1b, and 1-1c where illustrates a schematic diagram of an alternate embodiment of the present disclosure consisting (1a) where the thermal section in FIG. 1-1a can be replaced with a direct oxidation catalytic stage for lean gas application. Upon the emission requirements SETR is added to improve the sulfur recovery as necessary stage followed by 2 or 3 Claus stages, (1b) illustrates the incineration system that receives the tail gas stream from the last condenser directly, (1c) the innovative SETR scheme that receives the gas stream from the incineration outlet.

[0067] FIG. 3 consists of 3-3a, 1-1b, and 1-1c, where illustrates diagram of an alternate embodiment of the present disclosure illustrates the scheme from the patented process, May 5, 2015 (U.S. Pat. No. 9,023,309 B1) by M. Rameshni; as known as SMAX and SMAXB the zero SO2 emission is achieved by using the caustic scrubber system after the incineration where the caustic section is replaced by the SETR innovative process.

[0068] FIG. 4 consists of 4-4a, 1-1b, and 1-1c, where illustrates diagram of an alternate embodiment of the present disclosure illustrates the scheme from the patent pending of the application filed regard to SUPERSULF process (application Ser. No. 14/826,198, Aug. 14, 2015) the zero SO2 emission is achieved by using the caustic scrubber system after the incineration where the caustic section is replaced by the SETR innovative process.

[0069] FIG. 5 consists of 1-1a, 5-5a, 1-1b, 1-1c where illustrates diagram of an alternate embodiment of the present disclosure illustrates the feed gas stream to the incinerator comes from the tail gas absorber overhead in the tail gas treating system.

[0070] FIG. 6 consists of 6-6a, 6-6b, 1-1b and 1-1c where illustrates diagram of an alternate embodiment of the present disclosure illustrates the feed gas stream to the incinerator comes from the special design of the SRU and tail gas absorber as known as RICH-SMAX where the tail gas absorber performs as the partial acid gas enrichment and the tail gas recycle is routed to the second zone of the reactor furnace.

[0071] While the inventions disclosed herein are susceptible to various modifications and alternative forms, only a few specific embodiments have been shown by way of example in the drawings and are described in detail below. The figures and detailed descriptions of these specific embodiments are not intended to limit the breadth or the scope of the inventive concepts or the appended claims in any manner. Rather, the figures and detailed written descriptions are provided to illustrate the inventive concepts to a person of ordinary skill in the art and enable such person to make and use the inventive concepts.

DETAILED DESCRIPTION OF THE INVENTION

[0072] One or more illustrative embodiments incorporating the invention disclosed herein are presented below. Not all features of an actual implementation are described or shown in this application for the sake of clarity. It is understood that in the development of an actual embodiment incorporating the present invention, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government related and other constraints, which vary by implementation and from time to time. While a developer's efforts might be complex and time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill the art having benefit of this disclosure.

[0073] In general terms, Applicant has created new processes for the conversion of sulfur compounds to elemental sulfur using SETR reactors replaces the tail gas treating unit with less equipment while achieving 100% recovery without any waste stream or chemicals.

[0074] The present invention relates to processes for recovering sulfur for onshore and offshore applications; refineries, gas plants, IGCC, gasification, coke oven gas, mining and minerals sour gas field developments and flue gas desulfurization onshore and offshore wherein sulfur recovery unit is required for new units or revamps.

[0075] In accordance to aspects of this invention; the SETR reactor operates as the adsorbent and regenerator where the cycles are (cold, hot) and (hot, cold) to achieve higher recovery. In addition, the combination of adsorbent and regenerator operation are controlled by using 2-way or 3-way switching valves.

[0076] In accordance with aspects of the present invention, it is an object of the present disclosure to provide a process for producing elemental sulfur economically acceptable for, present day industrial operations and higher safety standard.

[0077] Another object is to provide such a process which can tolerate variances in operating conditions within a given range without major equipment adaptations. A further object is to provide a process which can be utilized in co-acting phases to provide, at acceptable economics, the capacity required in present-day industrial operations, easy to operate and more reliable and robust operation.

[0078] In the discussion of the Figures, the same or similar numbers will be used throughout to refer to the same or similar components. Not all valves and the like necessary for the performance of the process have been shown in the interest of conciseness. Additionally, it will be recognized that alternative methods of temperature control, heating and cooling of the process streams are known to those of skill in the art, and may be employed in the processes of the present invention, without deviating from the disclosed inventions.

[0079] In the reaction furnace, the hydrocarbon containing gas stream comprises one or more hydrocarbons selected from the group consisting of alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, and mixtures thereof.

[0080] The figures illustrate steam reheaters that heats up the gas by using steam, however, any suitable heat exchanger, using different heating media, or fired reheaters using natural gas or acid gas, and hot gas bypass maybe employed in this service.

[0081] The figure illustrates a waste heat boiler that produces steam, however, any suitable heat exchanger, such as a water heater, steam superheater or feed effluent exchanger may be employed in this service.

[0082] The reaction furnace is equipped with one or more checker wall or choke ring or vector wall to create the turbulent velocity of gas for a better mixing and to prevent cold spot and condensation. In addition the checker wall near the tube sheet of the waste heat boiler to protect the tube sheet from the heat radiation from the burner.

[0083] In accordance to this invention; the rate of the air, enriched air or oxygen enrichment stream is adjusted such that the mole ratio of hydrogen sulfide to sulfur dioxide in the gaseous-mixture reaction stream ranges from 1.5:1 to 10:1.

[0084] The innovative SETR process comprises at least one Claus catalyst, consisting of alumina, promoted alumina, and titania, but not limited to Iron with Zinc, Iron with Nickel, Cr, Mo, Mn, Co, Mg with promoter on Alumina and with any other combination or any other catalyst systems which are employed in the Claus process.

[0085] The converters in the Claus conversion step of this present process disclosure, employ one or more Claus catalysts including alumina catalysts, activated alumina catalysts, alumina/titania catalysts, and/or titania catalysts, Iron with Zinc, Iron with Nickel, Cr, Mo, Mn, Co, Mg with promoter on Alumina and with any other combination or any other catalyst systems which are employed in the Claus process, the catalysts having a range of surface area, pore volume, shapes (e.g., star shaped, beads, or powders), and percent catalyst content (in non-limiting example, from about 50 wt. % to about 95 wt. % Al2O3, having a purity up to about 99+%), without any limitations. The Claus processes within converter and subsequent converters, such as converter may be carried out at conventional reaction temperatures, ranging from about 200 C. to about 1300 C., and more preferably from about 240 C. to about 600 C., as well as over temperature ranges between these ranges, including from about 210 C. to about 480 C., and from about 950 C. to about 1250 C., without limitation.

[0086] The number of Claus conversion steps employed, which may range from one stage to more than ten, depends on the particular application and the amount of sulfur recovery required or desired. In accordance with certain non-limiting aspects of the present disclosure, the number and placement of multiple converters/reactors, and the associated condenser systems, may be adjusted without affecting the overall thermal reduction process described herein.

[0087] The process is typically able to achieve an overall sulfur recovery efficiency of greater than about 99.8%, and preferably greater than 99.99%, based on the theoretical amount of recoverable sulfur.

[0088] With continued reference to the invention, the tail gas stream upon exiting the last reaction stage may optionally be conveyed to any typical tail gas absorption process, BSR, SCOTT, ARCO, and RICH-SMAX or similar and any type of incineration process to increase sulfur recovery efficiency to about 100%.

[0089] Accordance to the present invention the detailed description of the figures are in 4 steps: Step 1Conventional Claus thermal stage with high intensity burner; step 2at least two Claus catalyst containing alumina titanium catalyst to hydrolyze COS and CS2 from the reaction furnace and to perform Claus reaction; step 3tail gas SETR reactors consisting of adsorption and regeneration mode of operation coordinated by 2 way or 3 way switching valves located on the tail gas feed, slip of air, slip of amine acid gas and the flue gas of each SETR reactor.

[0090] The last condenser is at least one heat exchanger or multiple heat exchangers, dual condensers or combination of water coolers and air coolers to achieve maximum sulfur condensation and sulfur recoveries.

[0091] The recovering process from catalytic zones of the catalytic stages comprises cooling the product gas stream in one or more sulfur condensers to condense and recover elemental sulfur from the product gas stream.

[0092] In the reaction furnace, the hydrocarbon containing gas stream comprises one or more hydrocarbons selected from the group consisting of alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, and mixtures thereof.

[0093] The new invention comprises that the SETR reactor operates as an adsorbent process and the mode of operation are cold and hot and switches to hot and cold by switching valves.

[0094] The new invention comprises that the sulfur recovery of up to 99.99% or less than 10 ppmv of SO2 in the stack is achieved.

[0095] All the heat exchangers defined in this process can be of any type of commercial exchangers such as but not limited to fired heaters, shell and tube, plate and frame, air cooler, water cooler, boiler type, or any suitable exchangers.

[0096] All required control systems in the sulfur recovery tail gas treating and incineration are defined based on the latest commercial control systems including but not limited to local panel, DCS control room, burner management systems in the sulfur plant, switching valves sequencer control systems, reactors, condensers, columns incineration and all necessary equipment in this innovation.

[0097] The sequence runs fully automatically without requiring any operator action. With the switch-over procedure finished, the zones changed their positions in the process and a new cycle starts.

[0098] Turning now to the FIG. 1 consists of the FIG. 1-1a, 1-1b and 1-1c. in the FIG. 1-1a, in the reaction furnace (1) the acid gas streams, streams 20, 21 are partially oxidized with air, enriched air or oxygen, stream 22 in the reaction furnace combustion chamber zones; (no. 2 and no. 4) according to the basic chemistry of the Claus process. The acid gas stream is split into two streams where stream 21 is combined with the ammonia acid gas and the remaining of the amine acid gas stream 23 flows to the second zone of the reaction furnace (4) to provide enough flexibility to the operators by adjusting the split flow to achieve the required combustion temperature for destruction of ammonia and hydrocarbons. The choke ring or checker wall or vector wall located inside of the reaction furnace is shown (5). The sulfur is formed as a vapor, and other forms of elemental sulfur are formed in the gas. Combustibles in the gas will burn along with the H2S, and sulfur compounds are formed with their combustion products. Also, H2S will dissociate at high temperature forming hydrogen and elemental sulfur. The regenerator gas recycle from the SETR tail gas unit (95) is added to the reaction furnace stream (100) or it is added to the outlet of the waste heat boiler stream (24). The location of the SETR recycle gas depends on the feed compositions that come from the SETR regeneration reactor and the necessary adequate temperature to process the gas.

[0099] In accordance to the invention SETR reactor, a slip stream of the amine acid gas stream (85) and a slip stream of the air or air enriched stream (90) is sent to SETR tail gas unit regeneration reactor to recover the sulfur compounds and recycled back to the Claus unit. Adding H2S will promote the Claus reaction where oxygen is present from the air stream.

[0100] Sulfur is formed thermally in the reaction furnace and the products from the exothermic reactions stream 25 are cooled in the Waste Heat Boiler (10) by generating high or medium pressure steam and then stream 26 further cooled in the No. 1 condenser (11) which generates low pressure steam.

[0101] The reaction furnace consists of a refractory checker wall near to the waste heat boiler to protect the tube sheet of the waste heat boiler from the heat radiation from the burner.

[0102] In the No. 1 Condenser (11) the liquid sulfur is separated and flows to the sulfur pit as stream (50) and the gas stream (28) flows to the No. 1 Claus repeater (12) prior entering to the No. 1 Claus reactor (13), with inlet stream of 30 and the outlet stream of 31.

[0103] The outlet of the first Claus reactor stream 31 flows to the No. 2 condenser (14) where the outlet stream of liquid sulfur (55) flows the sulfur pit and the cooled gas stream (33) flows to the No.2 Claus reheater (18) prior entering the No. 2 Claus reactor (19) with the inlet stream of (37) and the outlet stream of (38).

[0104] The outlet of the second Claus reactor stream (38) flows to the No. 3 condenser (20) where the outlet stream of liquid sulfur (65) flows the sulfur pit and the cooled gas stream (39) flows to the No.3 Claus reheater (20) prior entering the No. 3 Claus reactor (22) with the inlet stream of (40) and the outlet stream of (41).

[0105] The outlet of the third Claus reactor stream (41) flows to the No. 4 condenser (23) where the outlet stream of liquid sulfur (70) flows to the sulfur pit and the cooled gas stream (75) tail gas stream flows to the incineration.

[0106] The outlet gas from the No. 1 condenser (11) stream 28 is heated indirectly in the No. 1 reheater (12) by high pressure steam and then stream 30 enters the No. 1 converter (13) which the converter contains mostly Titanium catalyst to hydrolyze the COS and CS2 formed from the thermal section of this invention (1) plus contains Claus catalyst types such as alumina and promoted alumina catalyst to perform the Claus reaction; as the results Sulfur is formed by an exothermic reaction, which creates a temperature rise across the catalyst bed.

[0107] In the FIG. 1-1b, the incineration section the feed stream SRU tail gas stream (91) and the pit vent from the sulfur pit degassing vent stream (94) plus the fuel gas stream (93) flows to the incineration.

[0108] The incineration consists of a forced draft incinerator (30) and the air blower (31) and with the heat recovery (32). When heat is recovered then as part of energy saving, the additional steam is exported to the facility utility header. The combusted gas from the incinerator (30) is routed to the SETR tail gas treating reactor through the waste heat boiler (32).

[0109] In the FIG. 1-1c is shown SETR-SUPER ENHANCED TAIL GAS RECOVERY; A TAIL GAS PROCESS WITH ADSORBENT REACTORS and illustrates the heart of this invention by receiving the gas stream from the incineration system through a waste heat boiler or cooler where the combusted gas stream consisting the sulfur compounds in the form of SO2 (13) cools off further by the cooler (50) and stream (16) enters the SETR adsorbent reactor (10) where it operates at 125 C to 130 C to maximize the SO2 adsorption. In practice lower temperature will increase the adsorption capacity of SO2 but it is important to avoid the water dew point. In addition since the rate of the SO2 adsorption is limited larger residence time than Claus reactor may be needed.

[0110] The SETR reactors contain titanium catalyst as the top bed due to oxygen presence from the incinerator and alumina at the bottom where these catalysts have important role during the regeneration process. The adsorbent must be able to tolerate some oxygen and must also have capability to promote the Claus reaction in the regeneration mode therefore, titanium catalyst shall be provided in these SETR reactors.

[0111] Turning to FIG. 1-1C, the slip stream of the amine acid gas (15) and slip stream of air stream (14) from the combustion air blower flows to the SETR reactors during the regeneration mode establishing a Claus reaction and higher temperature due to exothermic reaction and the adsorbed SO2 will be regenerated faster. The SETR regeneration reactor operates at 320 C to 400 C to maximize the SO2 regeneration to promote the Claus reaction.

[0112] According to this innovation scheme, the regeneration procedure accomplishes a number of chemical transformations. Most importantly, SO2 is displaced by the hot gas and sulphate and thiosulphate which they are present on the surface of the adsorbent and after an uptake cycle are reduced by H2S in the regeneration stream of the amine acid gas, in addition any oxygen which is adsorbed in the uptake cycle will be removed by reaction with H2S.

[0113] The combusted gas from the incineration contains SO2, N2, CO2, H2S where will be adsorbed by the catalytic bed in form of O2, SO2, S2O3.sup. and SO4.sup.. During the regeneration SO2 and S2O3.sup. are desorbed and H2S and air is added the reactions are resulted in the Claus Equilibrium for the system.

H2S+3/2 O2.fwdarw.H2O+SO2

SO2+2H2S.fwdarw.2H2O+3S

SO4.sup./S2O3.sup.+H2S.fwdarw.H2O, S, SO2, H2S

[0114] The SETR innovative process is not a sub dew point process where the bed become saturated with sulfur, instead, the SETR process are fixed bed reactors that requires heat up and cool down for the SO2 adsorption-based Claus tail gas process.

[0115] The slip stream of the amine acid gas and the air from the combustion air blower will provide the adequate pressure or driving force to recycle the regenerated gas to the Claus unit. The recycle is added to the reaction furnace or to the outlet of the waste heat boiler.

[0116] During the adsorption mode of operation the outlet from the adsorbent reactor (7) flows to the stack (20) which is sulfur free. During the regeneration mode of operation the outlet from the regeneration reactor (6) flows back to the Claus unit.

[0117] The cold and hot are the two mode of operation where the two SETR reactors switch by using the switching valves automated control system. The switching valves are 2-way or 3way valves steam jacketed to prevent any plugging. FIG. 1-1c represents 5 switching valves as the 3-way switching valves (25, 30, 35, 40 and 45) located on 5 major lines to and from SETR reactors.

[0118] According to the new innovation SETR process the reactors are switching between 2 mode of operation cold and hot, where each cycle take around 24 hours.

[0119] The switching valves are located on (1) combusted gas from the incinerator to the cold bed adsorbent stream (1 and 8), (2) air stream to hot bed regeneration stream (2 and 9), (3) amine acid gas to hot bed regeneration stream (3 and 10), (4) the outlet gas from the hot bed regeneration stream that is recycled back to the Claus unit stream 6 from (4 and 11), (5) the outlet gas from the cold bed adsorbent gas stream to the stack stream 7 from (5 and 12).

[0120] The incinerator stack (20) receives the gas stream from the cold bed which is sulfur free, and the stack is equipped with the necessary analyzer monitoring system.

[0121] In order to achieve the maximum adsorption and regeneration the streams 13, 14 and 15 temperatures are controlled by adding the proper cooling or heating exchangers.

[0122] The SETR tail gas treating system replaces any type of Caustic scrubber system such as DYNAWAVE or any similar system.

[0123] The SETR process is cost competitive solutions and do need any chemicals, and not generate any waste stream, where the caustic scrubber system requires caustic as the chemical agent and spent caustic as the waste stream requires additional treatment to prevent any environmental issues.

[0124] The innovative SETR reactors contain components like SO2,S2O3.sup. and SO4.sup. during the cold mode of operation, as the results the proper materials is chosen to prevent any corrosion.

[0125] Turing to the FIG. 2 consists of the FIG. 2-2a, 1-1b and 1-1c, where the FIG. 2-2a is the same as FIG. 1-1aexcept the burner and reaction furnace is replaced by a catalytic direct oxidation where applies for the lean acid gas application. Acid gas flows to the repeater (1) then through the mixer (3) flows to a direct oxidation reactor (2) where air is added to the reactor to establish the Claus reaction. The remaining description and the scheme is the same as FIG. 1-1a and the tail gas stream flows to the incineration system FIG. 1-1b and then flows to SETR tail gas treating unit FIG. 1-1c. The direct oxidation catalyst types are Selectox, Titanium, or any direct oxidation catalyst suitable for this process.

[0126] Turning to the FIG. 3 consists of the FIG. 3-3a, 1-1b and 1-1c, where the FIG. 3-3a illustrates the scheme from the patented process, May 5, 2015 (U.S. Pat. No. 9,023,309 B1) by M. Rameshni; the zero emission is achieved by using the caustic scrubber system after the incineration where the caustic section is replaced by the SETR tail gas treating innovative process according to this invention.

[0127] In the patented process, May 5,2015 (U.S. Pat. No. 9,023,309 B1) by M. Rameshni, as known as SMAX and SMAXB the catalytic stages consist of the Claus stage one or two, the direct reduction stage and the direct oxidation stage where can achieve up to 99.5% sulfur recovery. The condensed sulfur is separated from the gas in a coalescer section that is integral within each condenser and fitted with a stainless steel wire mesh pad to minimize sulfur entrainment. The tail gas flows to the incineration system the FIG. 1-1b to convert all the sulfur components to SO2. The combusted product are cooled and flows to the SETR tail gas treating process which is illustrated as a new innovative process and it is shown as the FIG. 1-1C where the overall sulfur recovery of near 100% is achieved.

[0128] Turning to FIG. 4 consists of 4-4a, 1-1b, and 1-1c, where illustrates diagram of an alternate embodiment of the present disclosure illustrates the scheme from the patent pending of the application filed regard to SUPERSULF process (application Ser. No. 14/826,198, Aug. 14, 2015) the zero emission is achieved by using the caustic scrubber system after the incineration where the caustic section is replaced by the SETR innovative process.

[0129] In the patent pending process SuperSulf, (application Ser. No. 14/826,198, Aug. 14, 2015) consists of the sub dew point process with internal heating and cooling reactors and the switching valves are located on the utilities line. The process includes the tail gas treating with the amine section to achieve 99.9% sulfur recovery and with the Caustic zero emission is achieved. According to FIG. 4-4a in the sulfur recovery section of this application up to 99.5% sulfur recovery can be achieved. The tail gas stream from the last condenser flows to the incineration system the FIG. 1-1b to convert all the sulfur components to SO2. The combusted product are cooled and flows to the SETR tail gas treating process which is illustrated as a new innovative process and it is shown as the FIG. 1-1C where the overall sulfur recovery of near 100% is achieved. For large capacity sulfur plant the tail gas unit in this application can be kept and the SETR tail gas can be added after the incineration before the stack where the SETR reactors will be smaller due to processing less SO2.

[0130] Turning to FIG. 5 consists of FIG. 1-1a, 5-5a, 1-1b, and 1-1c where illustrates diagram of an alternate embodiment of the present disclosure illustrates the feed gas stream to the incinerator comes from the tail gas absorber overhead in the tail gas treating system. FIG. 5-5a represents a conventional tail gas treating including the hydrogenation reactor, quench system and the amine unit such as BSR, SCOTT, ARCO, RICH-SMAX and any similar scheme such as the tail gas scheme in the patent pending process SuperSulf, (application Ser. No. 14/826,198, Aug. 14, 2015. In FIG. 5, the scheme of the 1-1a, 1-1b and 1-1c is the same as FIG. 1 as described except in the FIG. 1a the acid gas stream recycle from the regeneration stream 110 from the amine regeneration overhead is added. If the sulfur plant includes the conventional tail gas treating with the amine section as shown on the FIG. 5-5a is a conventional tail gas treating where it receives the tail gas stream from the FIG la for further processing to increase more recovery of H2S and the tail gas absorber overhead flows to the incineration into the FIG. 1b and finally the combusted gas flows to the FIG. 1C SETR reactors which is the current innovative process and it is already described under FIG. 1.

[0131] Turing to the FIG. 6 that consists of FIG. 6-6a, 6-6b, 1-1b and 1-1c where illustrates diagram of an alternate embodiment of the present disclosure illustrates the feed gas stream to the incinerator comes from the special design of the SRU and tail gas absorber as known as RICH-SMAX where the tail gas absorber performs as the partial acid gas enrichment and the tail gas recycle is routed to the second zone of the reactor furnace.

[0132] The acid gas is split the acid gas from the amine unit where up to 75% of the amine gas entered the first zone of the reaction furnace and the SETR reactors and up to 25% of the acid gas is routed to the tail gas absorber stream (200) in addition to the quench overhead that flows to the tail gas absorber. The tail gas amine unit is designed with the much higher amine loading similar to the amine unit, so in Summary the FIG. 6-6a and 6-6b are similar to FIG. 1-1a and FIG. 5-5a accordingly except as noted.

(a) 25% of the amine acid gas is sent to the tail gas absorber known as RICH-SMAX Absorber stream 200 on FIG. 6-6a and shown on FIG. 6-6b as acid gas stream (300) from the SRU;
(b) The tail gas absorber overhead stream 64 flows to the incineration and then flows to SETR reactors;
(c) Up to 75% of the amine acid gas is sent to the FIRST ZONE OF THE REACTION FURNACE and the SETR reactors;
(d) The tail gas absorber operates at higher rich loading (0.2-0.3 mol/mol);
(e) The tail gas recycle from the tail gas regeneration unit is recycled to the SRU but not to the first zone, as stream (210) instead:
The acid gas from the tail gas regeneration column, which is hydrocarbon/mercaptan free, is recycled back to the SRU. It is preheated and flows to the second zone of the reaction furnace. The combusted gas from the zone 1 reaction furnace flows to the second zone through choke ring where the temperature is above ignition temperature, and burn the acid gas in the second zone and the combusted;
(f) The tail gas absorber shall be designed with 0.2 to 0.3 mol/mol loading. The acid gas loading in the tail gas absorber is normally 0.1 mol/mol maximum, and the acid gas loading for the amine absorber is normally 0.3 mol/mol, it means there is significant free amine in the tail gas absorber to process the portion of the acid gas. The tail gas absorber acts not only as a tail gas absorber but also as an enriched absorber without adding significant cost to the project. This scheme also removes the hydrocarbons/mercaptans, which cause problems in the second zone of the reaction furnace. As H2S concentration increases the 25% slipstream from the SRU feed to the tail gas absorber may be reduced as long the combustion temperature of 1100 C-1150 C. in the first zone of the reaction furnace is achieved.

[0133] The FIG. 1-1b and 1-1c will remain the same where the RICH-SMAX tail gas absorber overhead flows to the incineration system and the cooled combusted gas flows to the SETR reactors FIG. 1-1c and the same operation take place to achieve near zero emission.

[0134] In summary, the SETR innovative process is a tail gas treating system that can be added after the incineration to any type of sulfur recovery and the tail gas treating technology from the conventional Claus ranging up to 98% sulfur recovery, to any sub dew point processes like CBA, MCRC, Smartsulf, Sulfreen, and SuperSulf or similar ranging up to 99.9% sulfur recovery, to any direct reduction and direct oxidation, like SuperClaus, EuroClaus, SMAX, and SMXB or similar ranging up to 99.9% sulfur recovery, and to any tail gas treating like BSR, ARCO RICH-SMAX and SCOTT or similar ranging up to 99.9% sulfur recovery, and catalytic incineration or similar which by adding the SETR reactors results free sulfur emission in the stack near to 100% sulfur recovery.

[0135] The size of the SETR reactors are based on the SO2 needs to be processed in the adsorbent and regeneration stage and the duration of each cycle is the function of the SO2 adsorbent.

[0136] All of the compositions, methods, processes and/or apparatus disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions, methods, processes and/or apparatus and in the steps or sequence of steps of the methods described herein without departing from the concept and scope of the invention. Additionally, it will be apparent that certain agents which are both chemically and functionally related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes or modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicant, but rather, in conformity with the patent laws, Applicants intends to protect all such modifications and improvements to the full extent that such falls within the scope or range of equivalents.