Patent Application
20230339753
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This disclosure relate the integration of sulfur recovery to produce hydrogen, SO2, H2SO4, and fertilizer products. The present invention is combination of prior arts for producing SO2 from the acid gases containing H2S is processed in the suitable acid gas burner incineration with the excess air/oxygen and without fuel. The present invention also introduces the new technology to produce large quantity of H2 VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle. Iodine is used to produce the hydrogen.
H2 production, sulfuric acid and SO2 production process refers to an innovative process VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle. The process consist of the acid gas burner to burn all the acid gases with air, enriched air or oxygen and without using any fuel gas to produce SO2.
The present invention objectives are not only to produce hydrogen but also to produce SO2 that is converted to sulfuric acid or fertilizer products or to liquefied SO2 for other SO2 applications.
The other aspects of the present invention is to reduce CO2 emission and de-carbonization compare to prior arts of the commercial sulfur recovery technologies.
The present innovation can be applied to the gas plants, sour gas field developments, refineries, bio-refining, petrochemical plants, IGCC, LNG and any facilities that produce acid gases containing H2S.
In accordance with aspects of the present invention, full streams flow or a portion of one or both gases; amine acid gases and the sour water stripper gases (SWS) are sent to the present innovative technology for processing, which these gas streams are normally processed in the Claus sulfur recovery unit.
In other aspects of this innovation, the SO2 produced in the present invention can also be reacted with the SWS gas to produce ammonium sulfate or ammonium thiosulfate (NH4)2S2O3 as fertilizer products, which reduces the size of the Claus unit and ultimately to reduce or to eliminate SO2 and CO2 emissions.
The prior arts; Sulfur plant operation is a very complicated and challenging job. Acid gas feed to a sulfur plant usually includes wide variation in the volume and concentration of sulfur and other compounds, including a substantial amount of ammonia and amine acid gases in most plants. Theoretically, control of the thermal stage(s) using air, enriched air or oxygen for conversion of H2S to SO2 has permitted some processes to obtain extremely high recovery of sulfur whether for the 2:1 ratio for H2S to SO2 or for H2S-shifted operation. However, the unrecovered gases are sent to the incineration where requires significant fuel to combust the gas and the utility consumption in the tail unit are high and no hydrogen is produced.
In refineries they need to supply hydrogen for hydrotreater, some of tail gas processes and methane is normally used to generate hydrogen for using in their different units, wherein, the new invention the required hydrogen can be produced to supply the need inside of the refineries and to eliminate using methane or other process for this purpose.
Producing hydrogen has been evaluated in different ways, however, economic is the main factor as some described below.
Natural Gas Reforming/Gasification: Synthesis gas a mixture of hydrogen, carbon monoxide, and a small amount of carbon dioxide is produced by reacting natural gas with high-temperature steam. The carbon monoxide is reacted with water to produce additional hydrogen. This method is the cheapest, most efficient, and most common. Natural gas reforming using steam accounts for the majority of hydrogen produced in the United States annually.
A synthesis gas can also be created by reacting coal or biomass with high-temperature steam and oxygen in a pressurized gasifier. This converts the coal or biomass into gaseous components a process called gasification. The resulting synthesis gas contains hydrogen and carbon monoxide, which is reacted with steam to separate the hydrogen.
Electrolysis: An electric current splits water into hydrogen and oxygen. If the electricity is produced by renewable sources, such as solar or wind, the resulting hydrogen will be considered renewable as well, and has numerous emissions benefits. Power-to-hydrogen projects are taking off, using excess renewable electricity, when available, to make hydrogen through electrolysis.
Renewable Liquid Reforming: Renewable liquid fuels, such as ethanol, are reacted with high-temperature steam to produce hydrogen near the point of end use.
Fermentation: Biomass is converted into sugar-rich feed-stocks that can be fermented to produce hydrogen.
High-Temperature Water Splitting: High temperatures generated by solar concentrators or nuclear reactors drive chemical reactions that split water to produce hydrogen.
In the patent (U.S. Pat. No. 11,104,574 B2, dated August 2021) describes HYDROGEN SULFIDE MEDIATED WATERSPLITTING FOR HYDROGEN GAS AN SULFUR DIOXIDE PRODUCTION. Wherein, there is no acid gas burner incineration is used, in addition, in real operation, the acid gas is not pure H2S and contains other components and impurities from upstream units that causes side effects and instability in the process. The other disadvantage of this scheme is that only ⅓ of H2S is converted to sulfur and ⅔ is converted to SO2 and requires significant heat for decomposition and as the results, the hydrogen production is reduced. The chemical reaction represents H2S+2H2O→SO2+3H2.
In additions, U.S. Pat. No. 4,258,026 A, by March 1981 O'Keefe relates to the I2 decompositions and the chemistry and it is not relevant.
Other prior related arts refers to numerous studies have been conducted related to sulfur-Iodine and H2 production in nuclear plants, which the evaluations are based on pure H2S or minor impurities.
All of studies have a common basis and conclusion whereas, refers to a hydrogen economy will need significant new sources of hydrogen. Unless large-scale carbon sequestration can be economically implemented, use of hydrogen reduces greenhouse gases only if the hydrogen is produced with non-fossil energy sources. Nuclear energy is one of the limited options available. One of the promising approaches to produce large quantities of hydrogen from nuclear energy efficiently is the Sulfur-Iodine (S-I) thermochemical water-splitting cycle, driven by high temperature heat from a nuclear reactor.
The study was conducted by Benjamin Russ, Dated June 2009 for the US Department of Energy Nuclear plant, another study was conducted by Kentucky University, L. C. Brown, dated 2003, and the study was conducted by DOE Hydrogen program and Sandia National Labs by P. Pickard, dated May of 2005 using nuclear energy. The present invention refers to the gases are processed in the sulfur recovery units, as known as amine acid gases and sour water stripper gases.
In accordance with the aspects of the present innovation, the acid gas burner is designed to combust all the components in the acid gases and is converted to combusted products that prevent side effects, side reactions, and to establish stable operation based on real data. As the results, higher quantity of H2 is produced.
In accordance with the aspects of the present innovation, full acid gases stream or portion of the gases is processed and the verity of different products is produced.
The present disclosure reduces the energy and fuel consumptions, and the consumptions of other utilities such as cooling water, steam, and refrigeration system are reduced or eliminated.
The present disclosure reduces CO2 emission in addition to sulfur emission while the significant quantity of H2 is also produced.
This disclosure relates generally to Process the acid gases containing H2S and the sulfur compounds that is normally processed in the Claus unit, now to produce SO2, and H2 VIA the sulfur-Iodine the thermochemical cycle process.
The present invention relates to a process for acid gases that are combusted in the acid gas burner with excess air/oxygen to achieve complete combustion.
The burner are suitable to combust both amine acid gases and the sour water stripper gases above 900 C. The burner is selected with the proper material of construction and the proper refractory to handle such high temperature and the adequate residence time.
The acid gas streams that normally flow to the Claus unit at least containing H2S, COS, N2, HCN, phenol, CS2, CO2, H20, hydrocarbons, mercaptans, sulfur vapors and high ammonia content and any other sulfur compounds. Wherein, the sulfur compounds are converted to SO2 and ammonia is converted to nitrogen and water.
In the prior arts wherein, all the tail gas thermal incineration requires fuel gas to establish the stable combustion and to achieve the adequate combustion temperature, while in the present invention H2S with air or oxygen is combusted to produce SO2 without using fuel gas resulting lower CO2 emission.
Therefore, in the present disclosure, a portion of the acid gases or 100% of the acid gas that normally flows to the Claus; known as sulfur recovery process is sent to the new process that represents the innovative art, wherein, the acid gases is processed.
In the description of the present innovation, sometimes relevant part of prior arts are referenced or discussed in this application for comparison and sake of clarity.
In summary, the present invention comprises several steps for producing SO2 and H2 from the acid gases that containing sulfur compounds such as H2S and it is incinerated in the acid gas burner using only air and oxygen. Then the combusted gas is cooled off in two waste heat boilers to recover the heat wherein, in contact with Iodine, HI is converted to I2 and H2. Wherein, H2 and SO2 are separated as products.
step 1) In accordance with first aspects of the present invention, providing an acid gas stream that is normally processed in the Claus unit, into present invention; the acid gas burner incineration unit where H2S and all other sulfur compounds and ammonia, hydrocarbons in the feed reacts with excess air/oxygen to produce SO2, CO2 and other minor products; based on the reaction of H2S+3/2O2→SO2+H2O and 2NH3+3/2 O2→N2+3H2O.
step 2) In accordance with second aspects of the present invention, the combusted gas mixture from step 1 consists of SO2, 02,N2, H20 and SO3 is cooled off in the first waste boiler or H2SO4 Vaporizer and the energy/heat is produced is used in the process to heat up other streams or steam can be produced,
step 3) In accordance with third aspects of the present invention, the combusted gas mixture from step 2 is further cooled off and quenched in the tube side of a exchanger and is sent to a reactor;
step 4) In accordance with forth aspects wherein, in the shell side of the step 3 exchanger, I2, HI and water is added to heat up the mixture and the chemical reaction occurs and H2 and I2 is produced then the mixture is sent to a 3 phase separator to condense H2O which is recycled to step 5, wherein, H2 is separated from I2, and H2 is one of the product from the present innovation;
Step 5) In accordance with fifth aspects of the present invention, wherein, the cooled gas mixture, SO2, O2,N2, H2O and SO3 has two choices;
Step 6) In accordance with sixth aspects of the present invention wherein, the cooled gas from the reactor enters a quench column where N2 and CO2 is separated from the mixture, and is sent to CO2 removal or CO2 liquefaction unit, the bottom of the quench column consists of H2SO4, H2o, IH and HI flows to liquid-liquid contactor to separate H2SO4 from IH and I2 and recycled to step 4;
Step 7) In accordance with seventh aspects of the present invention H2SO4 from step 6, bottom of the liquid-liquid contactor is sent to a sulfuric acid concentration to concentrate the H2SO4 as another product on the present invention by using steam reboiler as desired and the water is removed.
In accordance with the present innovation, the acid gas containing H2S and sulfur compounds that are normally processed in the Claus sulfur recovery unit, is processed in the acid gas incineration burner to produce SO2 and to produce large quantity of hydrogen with the Sulfur-Iodine (S-I) thermochemical cycle.
The type of acid gases are processed in the prior arts of the Claus recovery are varied, sometime the acid gas is rich with H2S and sometimes is lean with H2S. For cases dealing with lean H2S and impurities like mercaptan or heavy hydrocarbons, processing lean gases are very difficult to achieve stable operation, and the overall recovery is low and SO2 and CO2 emissions are high, the present invention, solves this problem and the requirements of the acid gas enrichment is eliminated. The present invention is suitable for any acid gas compositions rich or lean H2S concentration.
According to public data, Sulfuric acid is decomposed at high temperature and hydrogen iodide at lower temperatures. There are significant chemical separations associated with each chemical reaction. Water is the primary solvent in the system and iodine is a very important solvent in the reaction.
Sulfuric acid cannot be separated from hydrogen iodide, by thermal means, without reversing the equilibria. This separation is readily accomplished in, the presence of a large excess of iodine, with the formation of two immiscible liquid phases, a light H2SO4/H20 phase and a heavy HI/I2/H2O phase. Cost effective hydrogen production, using the sulfur-iodine cycle, requires that hydrogen be generated from the heavy phase efficiently and without excessive capital requirements.
The reaction, where SO2 and 12 are added to water to produce H2SO4 and HI, operates with excess water and also with excess iodine to allow separation of the H2SO4 and HI, and includes a boost reaction to increase the concentration of the H2SO4 in water. The H2SO4 decomposition section includes concentration and decomposition to recover the SO2 and produce O2. The HI decomposition section chosen in this study uses reactive distillation of the HI, I2, H2O mixture to recover I2 and produce H2, but has a large recirculation flow back to the reaction section.
The sulfur-iodine thermochemical cycle generates hydrogen through the chemical reactions:
H2S+3/2O2→SO2+H2O 900° C.
2H2O+SO2+I2→H2SO4+2HI 120° C.
2HI→H2+I2 300-450° C.
Overall Reaction:
H2S+3/2O2+H2O→H2+H2SO4
In the present innovation wherein, the sulfur-Iodine (S-I) thermochemical cycle is used to produce hydrogen.
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. These figures present the combinations of the modified, upgraded, and revamped of the prior arts plus the present invention. A block flow diagram is shown as
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.
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.
In general, terms, Applicant has created new processes for the hydrogen production with the integration of the sulfur recovery unit.
The present invention relates to processes to produce hydrogen, SO2 and other relevant products to also reduce SO2 and CO2 emission, the new invention applies to onshore and offshore applications; refineries, gas plants, IGCC, gasification, coke oven gas, mining and smelters sour gas field developments and flue gas desulfurization, wherein, the acid gases contain H2S and sulfur compounds.
In accordance with aspects of the present invention, it is an object of the present disclosure to provide a process to produce hydrogen, and SO2 to reduce SO2 and CO2 emission and economically acceptable for, present day industrial operations and higher safety standard.
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.
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. Finally, the present invention is a polisher to existing arts therefore, the existing arts and their variations scheme of existing arts are discussed where their FEED stream enters the present invention of acid gas burner incineration.
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.
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.
The acid gas burner incineration may have multiple burner to prevent NOx formation during the ammonia burning with intercooling system between the acid gas burners and with mixing devices, 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 maybe added to protect the tube sheet from the heat radiation from the burner.
In accordance to this invention; the prior arts; sulfur recovery units may be modified to improve the operation wherein, the present innovation is integrated.
Once again, since the prior arts provides feed gas stream to the present invention;
The prior arts are upgraded, modified, revamped, and optimized by adding related equipment, adding piping, adding recycle from the present invention, changing the catalysts, adding instrumentation, modified existing equipment to be suitable.
In the prior arts; the last condenser may be modified or replaced as 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.
The new invention comprises that SO2 and CO2 emissions is reduced significantly, while hydrogen is also produced.
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.
All required control systems in the prior and new arts 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, incineration and adsorbers and all necessary equipment in this innovation.
The sequence runs fully automatically without requiring any operator action.
Turning now to the
The unrecovered H2S and the sulfur compounds from the prior arts are sent to the prior art incineration and using significant amount of fuel to convert the sulfur compounds to SO2. While the fuel gas needed due to low H2S concentration and burning fuel gas burning produces significant CO2 that is currently emitted to the atmosphere. If SO2 level is in acceptable range of the local regulations then SO2 and CO2 are both emitted. If SO2 level is not in the acceptable range of the local regulations, then SO2 is absorbed by Caustic, SETR process or others, but the CO2 is still emitted.
In accordance with the present invention, if the acid gases are burned in the acid gas burner first, then since the H2S concentration is high, there is no need to burn the fuel gas, the CO2 emission is reduced and the cost of fuel gas is eliminated. In addition, SO2 emission is reduced and the key advantage is hydrogen is also produced which is another cost saving.
Turning now to the current invention that consists of two pages as
Iodine is used as a solvent to produce H2, H2SO4 and SO2 VIA the sulfur-Iodine thermochemical cycle, wherein, Iodine is regenerated and reused in the process.
The amine acid gases, the sour water stripping gas and any other vent streams that contents the sulfur compounds streams 51,52 and 53 flows to the acid gas burner, 30 and the air stream 54 from the air blower 31, flows to the acid gas burner, 30 as shown on
The acid gas burner consists of the proper material of construction with the refractory inside to protect the metal at high combustion temperature ranging 900 C to 2000 C with 100% stoichiometry and excess oxygen to convert all of the sulfur compounds to SO2. To dissociate NH3, HCN, phenol and the components from the sour water stripping gas to water and nitrogen and the vent stream containing sulfur vapor and H2S to SO2.
The acid gas burner incineration consists of a suitable refractory and mixing devices such as choke ring, checker wall or vector wall to protect the tube sheet of the waste heat boiler from the heat radiation from the burner.
The acid gas burner, 30 can use air, enriched air with oxygen or high level of oxygen to the burner.
The burner is one to ten burner stages and depends on the acid gases to the burner, for cases NH3 is present, the configuration of staged burner or multiple burner is used to prevent NOx formation. High intensity burner operates effectively by using multiple burners and multiple cooling as WHB to achieve less than 20 ppmv of NOx according to the latest air quality regulations.
Due to high H2S concentration of the acid gases to the burner, using fuel to the acid gas burner is eliminated wherein, the present invention reduces CO2 emission.
In accordance to present invention, wherein, the acid gas feed streams to the acid gas burners consists one to 10 streams.
In accordance to present invention, wherein, Iodine is introduced as a solvent to produce H2, H2SO4 and SO2 VIA the sulfur-Iodine thermochemical cycle, wherein, Iodine is regenerated and reused in the process.
In accordance to present invention, wherein, the reaction temperature of HI to produce H2 as the product is preferable at 450 C and from 300 C to 500 C.
In accordance to present invention, wherein, the reaction temperature of SO2 with H2O with I2 present in the reactor is preferable at 120 C from 100 C to 200 C.
In accordance to present invention, wherein, the acid gas feed streams pressure to the acid gas burner is from 0.5 bar to 10 bar.
In accordance to present invention, wherein, the internal of the quench column, and the liquid-liquid contactor is high performance tray or packing.
In accordance to present invention, wherein, the produced H2SO4 is concentrated in the concentration column to achieve high purity of market grade H2SO4.
The combusted products from the acid gas burner 30, flows to the waste heat boiler, WHB 1, 32 to recover the combustion heat by producing HP steam or is used as a sulfuric acid vaporizer to vaporize some H2SO4, stream 67 and to recycle to the acid gas burner.
In accordance to present invention, wherein, a slip stream of produced H2SO4 is recycled to the acid gas burner through H2SO4 vaporizer.
The combusted cooled gas, stream 55 contains SO2, H2O, O2, N2 and H2SO4, enters tube side of WHB 2, 33 to cool the gas further and the outlet of WHB 2, 33 stream 56 enters the reactor.
The shell side of WHB 2, 33 receives H2O, I2 and HI as stream 65, wherein, the chemical reaction of 2HI→H2+I2 at 450 C with 3 phases mixture wherein, enters a 3 phase separator vessel, wherein, H2 is separated as the hydrogen product stream 60. Water is separated as stream 58 as recycle water. I2 is also separated as stream 57 to the reactor.
The hydrogen production is accordance on the present invention VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle.
The produced hydrogen can be used to supply the need within the facilities like hydrotreater units, and to eliminate the import of the external supply and to reduce the operating costs.
A portion of stream 56 can be sent to other units to produce other products like fertilizer products that are used in the agricultural industry or to process SO2 to liquefied SO2.
Streams 56, 57 and 58 flows to the reactor 35, refers to
All the sulfur compounds are converted to SO2, wherein, the SO2 emission is eliminated.
The mixture leaving the reactor stream 61 enters the quench column 36, to cool the mixture using air/water cooler not shown.
CO2 and N2 stream 62 is separated and is sent to CO2 liquefaction system or CO2 removal.
The liquid stream 64, from the bottom of the quench column 36, consists of H20, H2SO4, I2 and IH enters the liquid-liquid contactor 38, to separate H2SO4 from the I2 and IH. The recovered I2 and IH stream 65 is recycled back to WHB 2 as the thermochemical agent.
The sulfuric acid stream 66 flows to the sulfuric acid concentration unit 39, to concentrate the H2SO4 by removing water using reboiler as media.
Stream 70 represents sulfuric acid as another product.
In summary, the present invention, introduces a process to produce H2, produce SO2, produce H2SO4, while CO2 and SO2 emission is reduced or eliminated. The integration of sulfur recovery prior arts with the present invention produces H2 a valuable product, while SO2 and CO2 emissions are lowered or eliminated. The produced SO2 and CO2 is liquefied to use in other industries.
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.
