Patent Application
20240060411
The disclosure relates to systems and methods to photolytically cleave hydrogen sulfide (H2S) present in a gas mixture produced by a hydrocarbon producing well and/or a gas treatment unit, thereby converting the hydrogen sulfide to hydrogen gas (H2) and a sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds). This reduces the amount of hydrogen sulfide present in the gas mixture. The systems and methods can be implemented in a component of a hydrocarbon producing well (e.g., a wellhead, a flow line, a production casing, a production tubing), a component used to transport the gas mixture produced by the well (e.g., a transportation pipeline, an inlet to a gas-oil separation plant), and/or a gas treatment unit (e.g., a tail gas treatment unit). The gas mixture is disposed in an annular space of the component(s), and an ultraviolet (UV) light source delivers UV light to the gas mixture to photolytically cleave the hydrogen sulfide.
It is common for a well to produce a gas mixture containing hydrocarbons (e.g., methane, ethane, butane, propane), as well as one or more additional constituents, such as hydrogen sulfide. The hydrogen sulfide can cause corrosion of one or more components of the well or one or more components used to transport the hydrocarbon-containing gas mixture. Therefore, it is generally desirable to reduce the amount of hydrogen sulfide in the gas mixture. Catalysts have been used to try to achieve this goal.
The disclosure relates to systems and methods to photolytically cleave hydrogen sulfide (H2S) present in a gas mixture produced by a hydrocarbon producing well and/or a gas treatment unit, thereby converting hydrogen sulfide to hydrogen gas (H2) and a sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds). This reduces the amount of hydrogen sulfide present in the gas mixture. The systems and methods can be implemented in a component of a hydrocarbon producing well (e.g., a wellhead, a flow line, a production casing, a production tubing), a component used to transport the gas mixture produced by the well (e.g., a transportation pipeline, an inlet to a gas-oil separation plant), and/or a gas treatment unit (e.g., a tail gas treatment unit). The gas mixture is disposed in an annular space of the component(s), and an ultraviolet (UV) light source delivers UV light to the gas mixture to photolytically cleave the hydrogen sulfide.
In certain known methods, catalysts (e.g., photocatalysts) are disposed in the hydrocarbon producing well to remove hydrogen sulfide. However, in such methods, the catalyst can degrade over time (e.g., due to photobleaching) and lose its efficiency. As a result, these methods can involve interventions to replace the catalyst. Such interventions can pose significant costs and/or safety hazards. In contrast, the systems and methods of the disclosure can be implemented with relatively few (if any) well interventions. In some embodiments, the systems and methods of the disclosure can be implemented without using a catalyst (e.g., a photocatalyst).
More generally, the systems and methods of the disclosure can be implemented with relatively small modifications to existing infrastructure, can increase the lifetime of materials, reduce component maintenance, reduce costs and/or risks related to maintenance and/or damage associated with corrosion due to hydrogen sulfide, reduce (e.g., avoid) well interventions relative to certain other methods for addressing hydrogen sulfide reduction, and/or reduce (e.g., avoid) costs and/or safety risks associated with a well intervention.
The systems and methods of the disclosure can remove hydrogen sulfide with little (if any) precipitation and/or deposition of the reaction products. As an example, the systems and methods of the disclosure can generate hydrogen gas and a sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) upon the photocleavage of hydrogen sulfide, for example, in mildly sour wells (relatively low hydrogen sulfide concentration in the hydrocarbon-containing gas mixture). In a mildly sour well, the concentration of the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) may be sufficiently low such that it is soluble in a component of the produced hydrocarbon-containing gas mixture (e.g., methane, carbon dioxide and/or hydrogen sulfide). Under such conditions, a sulfur purge can be avoided. At higher hydrogen sulfide concentrations, one or more sulfur purge systems can be used to remove the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) from the produced hydrocarbon-containing gas mixture to reduce (e.g., avoid) precipitation and/or deposition of sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) within the well and/or related systems. Because the solubility of the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) in the components of the hydrocarbon-containing gas mixture generally increases with temperature, the sulfur purge system(s) can contain one or more heating devices. Further, the recombination of hydrogen gas and sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) has disfavored kinetics under typical temperature and pressure conditions of the hydrocarbon-containing gas mixture. This can enable a flow line and/or component to transport the hydrocarbon-containing gas mixture with little (if any) recombination of the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) and hydrogen gas.
In a first aspect, the disclosure provides a system, including at least one component of a hydrocarbon producing well, at least one component configured to transport a hydrocarbon produced by a hydrocarbon producing well and/or a gas treatment unit, the member includes an interior space, a gas mixture including hydrogen sulfide disposed in the interior space of the member, and an ultraviolet (UV) light source configured to deliver ultraviolet (UV) light to the gas mixture to photolytically cleave the hydrogen sulfide.
In some embodiments, the member includes a wellhead, a flow line, a production casing, a production tubing, a transportation pipeline, an inlet to a gas-oil separation plant and/or a tail gas treatment unit.
In some embodiments, the ultraviolet light source is configured to deliver the UV light perpendicular to a direction of flow of the gas mixture within the interior space.
In some embodiments, the interior space includes an annular region.
In some embodiments, the system includes a reflective material configured to reflect the UV light after it has traversed at least a portion of the gas mixture causing it to traverse at least a portion of the gas mixture a second time.
In some embodiments, the system includes a sulfur purge configured to remove a sulfur-containing product of the hydrogen sulfide photolysis from the system.
In some embodiments, the UV light source includes a window having anti-reflectivity, transmissibility, self-cleaning, photonic resonance, plasmonic resonance and/or catalytic properties.
In some embodiments, the UV light source includes a window, the window includes a self-cleaning coating, and the self-cleaning coating includes diamond, silica, sulfides, PVDF, nitrides, carbides, fluoride and/or titanate nanofilms.
In a second aspect, the disclosure provides a system, including a first photolytic reactor tube including a first gas inlet, a first gas outlet in fluid communication with the first gas inlet, and an ultraviolet (UV) light source configured to generate ultraviolet (UV) light and a sulfur purge unit, including a sulfur inlet, a heat source, and a sulfur outlet. The UV light source is configured to expose a gas including hydrogen sulfide in the first photolytic reactor tube to UV light generated by the UV light source so that the UV light cleaves the hydrogen sulfide to produce hydrogen gas and a sulfur-containing product. The sulfur purge unit is in fluid communication with the first gas outlet and the sulfur purge unit is configured to remove the sulfur-containing product from the system.
In certain embodiments, the sulfur purge unit is configured so that, during use of the sulfur purge unit, the sulfur-containing product enters the sulfur purge unit via the sulfur inlet, is heated by the heat source to at least partially liquefy the sulfur-containing product, and the sulfur-containing product leaves the system through the sulfur outlet.
In certain embodiments, the first gas inlet is configured to be in fluid communication with a hydrocarbon-containing gas mixture produced by a well, the first gas outlet is in fluid communication with at least one component configured to transport the gas mixture, and when the gas mixture contains hydrogen sulfide, the UV light hydrolyzes the hydrogen sulfide to remove hydrogen sulfide from the gas mixture.
In certain embodiments, the first photolytic reactor tube includes a plurality of UV light sources.
In certain embodiments, the system includes a second photolytic reactor tube including a second gas inlet, a second gas outlet in fluid communication with the second gas inlet, and a second UV light source configured to generate UV light, wherein the second UV light source is configured to expose a hydrogen sulfide-containing gas in the second photolytic reactor tube to UV light generated by the second UV light source so that the UV light cleaves the hydrogen sulfide to produce hydrogen gas and the sulfur-containing product.
In certain embodiments, the system includes a second sulfur purge unit in fluid communication with the second gas outlet, wherein the second sulfur purge unit is configured to remove the sulfur-containing product produced in the second photolytic reactor tube from the system.
In certain embodiments, the gas inlet is in fluid communication with at least one component of a hydrocarbon producing well.
In certain embodiments, the gas outlet is in fluid communication with a component to transport a hydrocarbon.
In a third aspect, the disclosure provides a method, including using ultraviolet (UV) light to hydrolyze hydrogen sulfide in a first gas mixture produced by a hydrocarbon producing well while the first gas mixture is disposed in an interior space of at least one component of a hydrocarbon producing well, at least one component configured to transport a hydrocarbon produced by a hydrocarbon producing well, and/or a gas treatment unit, thereby photolytically cleaving the hydrogen sulfide to remove at least some of the hydrogen sulfide from the first gas mixture to produce a second gas mixture. The first gas mixture includes a hydrocarbon and/or carbon dioxide
In some embodiments, the member includes a wellhead, a flow line, a production casing, a production tubing, a transportation pipeline, an inlet to a gas-oil separation plant, and/or a tail gas treatment unit.
In some embodiments, the photolytic cleavage of the hydrogen sulfide produces a sulfur-containing product, and the method further includes removing the sulfur-containing product from the member.
In some embodiments, the method includes transporting the second gas mixture to a downstream system.
Generally, the positioning, alignment and number of the UV light source 1300 may be selected as appropriate to photolytically cleave the hydrogen sulfide in the region 1400. Thus, while
In some embodiments, the wavelength of the UV light source is at least 100 (e.g., at least 125, at least 280) nanometers (nm) and at most 380 (e.g., at most 315, at most 280) nm. In some embodiments, the wavelength does not cause methane photolysis. Generally, the power is determined by the concentration of hydrogen sulfide and the gas flow rate. In some embodiments, the UV light source has an intensity of at least 1 milliwatt (e.g. at least 1 watt, at least 1 kilowatt) and at most 1 megawatt (e.g. at most 1 kilowatt, at most 1 watt).
In general, the UV light source can be used with any appropriate optical components. As an example, the UV light source 1300 can be used in combination with lenses, optical fibers (e.g. solid-core optical fibers, hollow-core optical fibers), electromagnetic waveguides, mirror and/or meta-surfaces. In certain embodiments, the UV light source 1300 can be used in combination with lenses and/or metasurfaces to create non-Gaussian self-healing beams with low angular spreading (e.g., Bessel or Airy beams). In certain embodiments, the optical elements are placed external to a component of a hydrocarbon producing well (e.g., a wellhead, a flow line, a production casing, a production tubing), a component used to transport the gas mixture produced by the well (e.g., a transportation pipeline, an inlet to a gas-oil separation plant), and/or a gas treatment unit (e.g., a tail gas treatment unit) to reduce (e.g., prevent) the need for a well intervention.
In some embodiments, the UV light source 1300 can be used with a UV window. In some embodiments, the UV window contains a self-cleaning element or property. In some embodiments, the self-cleaning element is hydrophobic material, a super hydrophobic material, an oleophobic material, a super oleophobic material, an omniphobic material and/or a super omniphobic material. In some embodiments, the self-cleaning element contains diamond, silica, sulfides, polyvinylidene fluoride (PVDF), nitride, carbide, fluoride and/or titanate nanofilms. In certain embodiments, the UV window is modified to provide one or more desirable properties. In certain embodiments, the desirable property is anti-reflectivity, transmissibility, self-cleaning, photonic resonance, plasmonic resonance and/or catalytic properties. In certain embodiments, the modification involves adding at least one layer to the UV window.
Without wishing to be bound by theory, it is believed that at relatively high concentrations of hydrogen sulfide, the solubility of sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) generated from the photolytic cleavage of hydrogen sulfide can potentially become so large that the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) formed may not undergo complete dissolution in the hydrocarbon-containing gas mixture, thereby potentially resulting in precipitation and/or deposition of the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) within the well and/or components used to transport the hydrocarbon-containing gas mixture. The system 2000 is configured so that the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) that is not soluble in the hydrocarbon-containing gas mixture collects in the sulfur purges 2300. In some embodiments, traces of methane and/or other light hydrocarbons may also collect in the sulfur purges 2300. The sulfur purges contain a heat source 2310, a first actuator valve 2320, a second actuator valve 2330, and a sulfur outlet 2340. The first actuator valve 2320 can open to allow precipitated sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) to flow to a region adjacent the heater 2310. When adjacent the heater 2310, the precipitated sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) is converted to a liquid and/or semi-liquid. The second actuator valve 2330 can open to allow the liquid and/or semi-liquid sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) to exit the system 2000 by flowing through the outlet 2340. The hydrocarbon-containing gas mixture exits the system 2000 via the outlet 2400. A three-way valve 2390 connects the gas outlet 2400 and the photolytic reactor tubes 2200. In some embodiments, the liquid and/or semi-liquid sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) are removed from the system 2000 without gas leakage. In some embodiments, the first actuator valve 2320 is closed when the second actuator valve 2330 is opened. In some embodiments, when the second actuator valve 2330 is opened, the three way valves 2110 and 2390 are used to divert flow to the other flow path.
In general, the various components of the system 2000 can be oriented as appropriate. As shown in
In certain embodiments, the system 1000 and/or the system 2000 can further include one or more UV reflecting surfaces. In some embodiments, the UV reflecting surfaces contain polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), aluminum and/or stainless steel. Without wishing to be bound by theory, it is believed that the UV reflecting surfaces can be used to increase the path length of the UV light and increase the contact time of the UV light with the gas mixture thereby increasing the amount of photolytic cleavage of hydrogen sulfide relative to the absence of the UV reflecting surfaces. For example, in some embodiments, it is believed that the UV reflecting surface(s) can allow the UV light to pass through the gas mixture multiple times. In some embodiments, the UV reflecting surfaces can create a resonating cavity lengthwise or through the entire body of the system 2000. Additional parallelization and/or miniaturization within the photolytic reactor tubes 2200 is possible.
In general, the heat source 2310 is configured to heat the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) so that it becomes a liquid and/or semi-liquid. In some embodiments, the heat source 2310 heats the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) to a temperature of at least 110 (e.g. at least 115, at least 120) ° C. and at most 450 (e.g. at most 444, at most 440) ° C.
In some embodiments, the system 2000 can further include one or more sensors to monitor one or more parameters of interest, such as, for example, the sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) level of the sulfur purge 2300. As an example, such sensors could be used to determine when to switch between different sulfur purges (e.g., left sulfur purge or right sulfur purge as depicted in
In certain embodiments, the sulfur outlet 2340 has a “U” shaped trap. Without wishing to be bound by theory, it is believed that the “U” shaped trap can reduce (e.g., prevent) gas discharges into subsequent containers, such as, for example, those present in a gas-oil separation plant. In certain embodiments, the sulfur outlet 2340 is connected to a sulfur pit.
Further sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) separation techniques may be employed. As an example, such techniques can be employed to provide laminar flow and/or reduce recombination rates of the hydrogen gas and sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) to reform hydrogen sulfide.
A UV light source can be configured (e.g., as discussed above) to deliver UV light to the interior of the portion 3110 (e.g., a wellhead), the interior of the portion 3120 (e.g., the casing 3122, a production tubing), and/or the interior of the pipe 3400, so that the UV light photolytically cleaves hydrogen sulfide present in the hydrocarbon-containing gas mixture, generating sulfur species (e.g., elemental sulfur, polysulfides, and/or organosulfur compounds) and hydrogen gas, thereby reducing the amount of hydrogen sulfide contained in the hydrocarbon-containing gas mixture.
While certain embodiments have been disclosed above, the disclosure is not limited to such embodiments.
As an example, while embodiments have been disclosed that include systems and methods related to hydrocarbon production, the disclosure is not limited to such embodiments. In some embodiments, the systems and methods of the disclosure can be used in sewage and/or metallurgy applications.
As another example, while
As an additional example, while embodiments have been disclosed in which a system and/or method does not use a catalyst (e.g., a photocatalyst), the disclosure is not limited to such embodiments. Rather, in some embodiments, the systems and methods of the disclosure can further include a catalyst (e.g. a photocatalyst) to assist in the cleavage of H2S.
As a further example, while embodiments have been described involving a hydrocarbon gas, in some embodiments, the gas mixture can contain carbon dioxide in addition to, or instead of, hydrocarbon gas.
