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    • 专利摘要:
    PROCESS FOR THE SEPARATION OF MERCAPTAN COMPOUNDS FROM A CURRENT RICH IN CAUSTICS, AND, SINGLE TOWER TO TREAT A CURRENT RICH IN CAUSTIC CONTAINING MERCAPTANO COMPOUNDS. A separation process to separate two or more immiscible liquids using contacts using fibers in vertical suspension with a high surface area is described, this separation process is especially usable in separating the disulfide oil formed during the oxidation of the caustic solution used to remove contaminants sulfur content of light hydrocarbons.
    公开号:BR112013001954B1
    申请号:R112013001954-9
    申请日:2011-07-27
    公开日:2020-11-03
    发明作者:Tiejun Zhang；V. Keith Turner
    申请人:Merichem Company；
    IPC主号:
    专利说明:

    CROSS REFERENCE FOR RELATED ORDERS
    [1] This application claims the benefit of U.S. Patent Application No. 12 / 849,408, filed on August 3, 2010, which is incorporated herein as a reference in its entirety. FIELD OF THE INVENTION
    [2] Applicants' invention typically relates to a new separation technology that uses the high surface area and coalescence properties of fibers in vertical suspension with a high surface area to achieve rapid separation of two immiscible liquids. A specific application of the applicants' invention relates to an improved separation process that is conducted in a single vessel where a mixture of disulfides and caustic solution created during a process to remove sulfur and other contaminants from hydrocarbons, including liquid petroleum gas ( "LPG"), is separated into an aqueous caustic stream for recycling and an organic stream containing the disulfides. Applicants' invention significantly reduces separation residence times, thereby reducing equipment costs and improving overall process efficiency. BACKGROUND
    [3] The separation of two immiscible liquids into two separate liquid layers for the recovery of each is well known in the art. However, most separation devices rely primarily on large vessels that use gravity and long residence times to achieve phase separation or the formation of distinct layers. Alternatively, the forced physical separation of the two liquids is carried out using complex mechanical devices, such as centrifuges, which also require a large energy input, or using membranes with selective permeability characteristics. With pressing needs for more economical processes that are also more compact to save space, smaller, more efficient separation is required.
    [4] The American Clean Air Act of 1990 reached its zenith in North America with the gasoline pool being required to contain less than 10 ppmp of sulfur. This means from a practical point of view that the refinery produces a pool of gasoline containing less than 5-ppmp to allow contamination of the pipelines with sulfur residues "adhered" to the wall of previous shipments and the accuracy of the test method dictated by the Clean Air Law.
    [5] Another consequence of the Clean Air Act of 1990 was the closure of small inefficient refineries that went from more than 330 refineries in 1980 to less than 175 refineries in 2007. No new refineries have been built in the past 25 years, but Refinery expansions and imports have satisfied America's gasoline demand.
    [6] Existing refineries have also undergone more stringent operations at the Fuido Catalytic Cracking Unit to reduce the amount of fuel in the burner while producing higher octane rating gasoline and increased olefin production. These olefins are propane / propylene and butane / isobutane / isobutylene. These are the feed charges for the next processing step which is an alkylation unit. Some refineries alkylate amylenes (pentene) depending on their economic models.
    [7] Most refineries use either HF (hydrofluoric acid) or a sulfuric acid alkylation unit to alkylate mixed butylenes or mixed propylenes and butylenes. Alkylation is a process where isobutane reacts with olefin to produce branched-chain paraffin. Since sulfur is detrimental to the alkylation process, a caustic treatment system is in place at most refineries to extract the easily extracted methyl and ethyl mercaptans and the most difficult propyl mercaptans present in the liquid petroleum gas stream (" GPL ") mixed olefinic.
    [8] Typically, liquid-liquid contactors are employed for the treatment of caustics and in some cases FIBER FILM® contactors, which are marketed and sold by Merichem Company (Houston, TX) and as described in U.S. Patent Nos. 3,758,404; 3,977,829 and 3,992,156, all of which are incorporated herein by reference. To save caustic, a caustic regenerator is almost always employed. A typical process flow scheme for treating LPG involves a first caustic treatment using a liquid-liquid contactor to extract sulfur contaminants, typically mercaptans, from the LPG supply, which generates a "used" caustic solution that is rich in mercaptan or so called rich in caustics, separate the LPG in the contactor, oxidize the rich caustic to convert mercaptans to disulfides (typically referred to as disulfide oil ("DSO")) which generates an "oxidized" caustic solution, and then use a gravity separator to separate the DSO from the oxidized caustic solution. In some instances, a granular coal bed is used in conjunction with the gravity sedimentation device as a coalescer to further assist the separation of the DSO from the oxidized caustic. Once the DSO is removed, the regenerated caustic can then be recycled and mixed with the new topping caustic and used in liquid-liquid contactors to treat the LPG feed.
    [9] As mentioned, the use of gravity sedimentation devices in prior art processes is plagued by the requirement for long residence times, especially when applied to separate DSO from an oxidized caustic solution. These long residence times have a negative impact on the economy of the caustic treatment process. In addition, prior art gravity sedimenters are relatively large pieces of equipment. Likewise, forced separation devices, such as centrifuges, are complex mechanical devices that require a large input of energy to operate. Applicants' invention now solves the problems encountered in the prior art separation equipment when two immiscible liquids require separation and particularly when applied for the separation of DSO from caustic solutions. In particular, the applicants' invention performs the entire process in a single column. Applicants' invention also uses two new improvements that can be used separately or in combination. The first involves the use of FIBER FILM® technology, which is found only typically in liquid-liquid contact applications, and the second involves the use of solvent injection before oxidation of the used caustic solution. The claimant's process may also use one or more polishing steps after separation of the DSO to further remove residual DSO from the oxidized caustic solution. The greatly reduced residence times and the reduced size of the equipment translate into an extremely economical method of removing sulfur compounds from the LPG, and consequently, minimizing capital and operating costs. These and other advantages will become apparent from the following more detailed description of the invention. SUMMARY
    [10] As mentioned, applicants' invention relates to an improved separation process to separate a mixture of at least two immiscible liquids in a single tower, column, or vessel using FIBER FILM® technology and finds specific application in the separation of DSO and other hydrocarbons from a caustic solution. Applicants' invention achieves separation residence times many times faster than conventional gravity sedimenters whether or not such conventional sedimenters use a coal bed as a coalescer. In addition, the applicants found that the use of a small amount of solvent added before the oxidation step further improves the separation performance compared to conventional gravity settler technology.
    [11] Although the use of FIBER FILM® technology is well known in applications with the co-current liquid-liquid contactor in which two immiscible liquids come into contact with each other for increased mass transfer of certain compounds, the technique recognized that FIBER FILM® technology is able to perform a real separation of two immiscible liquids fed as a mixture in a single current and that two or more stages in the contactor, each containing multiple fibers in vertical suspension, can be configured in a countercurrent model to achieve even greater separation without multiplying solvent consumption. This is despite the fact that FIBER FILM® technology has been on the market for over 35 years although the need for an improved and efficient separation process has been around for a long time. Likewise, applicants are not aware of the use of FIBER FILM® technology for separation because the fibers do not provide the selectivity resulting from the physical size restriction as in membrane technology, nor do they force the physical separation by large energy input such as in centrifuge technology. Instead, applicants' invention uses fibers with large surface areas to form thin liquid films within which a coalescing effect is achieved due to a drastically restricted path length.
    [12] In prior art processes, such as those taught in Pat. U.S. Nos. 5,017,294 (Derrieu) and 5,480,547 (Williamson), the processes are designed to separate aqueous droplets (where the aqueous phase is discontinuous) from organic hydrocarbon (which is continuous). When fibers are used, the water droplets moisten the surface of the fiber and coalesce to coat the fibers and run along the fibers. However, it was not known or obvious whether such FIBER FILM® technology could be used to separate organic droplets from the continuous aqueous phase when the fibers are wetted by the aqueous phase. Likewise, it was not known to applicants what level of separation of organic hydrocarbons could be achieved by such technology. Applicants have surprisingly found that separating dissolved organic or organic droplets from the aqueous caustic solution is in fact possible using FIBER FILM® technology. In the invention of the applicants, the fibers are still moisturized by the aqueous phase, however, the droplets of dissolved organic and organic hydrocarbons coalesce, not due to their contact with the fibers, but due to the limit imposed on them by the short way that they can move around the inside of the thin film of the aqueous phase that forms around the fiber. A closer look at the prior art processes mentioned above indicates that those processes are aimed at removing aqueous droplets or so-called free "water" and are not effective for removing dissolved water from the organic phase. In applicants' invention, applicants remove free organic droplets as well as dissolved organic droplets (solvent + DSO).
    [13] As used herein, disulfide oil or DSO means to include a mixture of possible disulfides, including dimethyl disulfide, diethyl disulfide, methyl ethyl disulfide and higher disulfides. Likewise, the term mercaptan includes any of a class of organo-sulfur compounds that are similar to alcohol and phenol, but containing a sulfur atom in place of the oxygen atom. Compounds containing -SH as the main group directly attached to carbon are called "thiols".
    [14] One aspect of applicants' invention involves using only a single piece of equipment (ie, a single tower) to oxidize an organic stream to convert contaminants followed by a separation of at least two immiscible liquids, such as, but not limited to, a mixture of water, or an aqueous solution, and hydrocarbons. This mixture is fed as a single stream to a separation device where the single stream contacts a bundle of fibers with a high surface area. As the mixture comes into contact and travels through the numerous individual fibers, a thin film of liquid is formed around each fiber and a coalescing effect is achieved due to the drastically restricted path length within the liquid film. In conjunction with the exceptionally high surface area of the fiber films, the two liquids separate quickly from each other and form two separate layers in a collection zone at the bottom of the separation device. The two distinct layers of liquids, a lower layer comprising the higher density liquid and an upper layer comprising the lower density liquid allows each to be removed separately from the separation device. Examples of mixtures that benefit from the applicants' new separation process of the invention include, but are not limited to, hydrocarbon mixtures, such as propane, butanes, pentanes, condensate, natural gas, molecular sieve regeneration gas, diesel, kerosene, gasoline, lubricating oils, light crude, edible oil, biofuel, biodiesel, products from the reaction of biodiesel, and any products from the reaction of a petrochemical plant such as polyols, POSM, and vinyl chloride and water, with water or a solution aqueous, including acidic, neutral or basic solutions that may contain dissolved salts and other organic or inorganic constituents. As a result of using FIBER FILM® technology, applicants have found that residence times are greatly reduced by an order of magnitude compared to conventional gravity sedimentation equipment. Applicants believe that this is caused by the increased interfacial surface area compared to a conventional gravity separator (CGS), even in circumstances where the CGS uses a coal bed as a coalescer.
    [15] Applicants' invention also finds specific application in processes to remove sulfur contaminants from LPG and other hydrocarbon streams where the caustic-rich stream containing mercaptan compounds is fed to an oxidizer. In the oxidation of mercaptan compounds to form DSO with a conversion level of 90% or greater in the presence of an oxygen-containing gas, which results in the formation of a mixture of DSO, caustic and gas; feeding this mixture as a single stream to a separation device where the mixture comes in with a bundle of fibers in vertical suspension; separating the DSO from the caustic within the separation device forming two distinct layers in a collection zone at the bottom of the separation device, where the lower layer comprises a caustic phase and the upper layer comprises DSO; and removing the DSO from the separating device by removing a portion of the upper layer and removing the caustic from the separating device by removing a portion of the lower layer.
    [16] Although the technique has recognized that gravity sedimentation can be used to separate water (or an aqueous solution) from hydrocarbons, those separation techniques from the prior art require the use of one or more liquid-liquid contactors downstream from the CGS where a solvent stream is used to wash the separate oxidized caustic solution to extract residual DSO to acceptable levels so that the caustic is suitable to be recycled back to the first section of the liquid-liquid contactor where the contaminated hydrocarbons, like LPG, are fed. Applicants' invention replaces both CGS and liquid-liquid contactors downstream with a single process vessel containing the oxidizer and one or more stages of separation using fibers in vertical suspension. This clearly saves capital and operating costs, but it also saves valuable real assets because your energy expenditure is much less than the combination of CGS and liquid-liquid contactors. As mentioned, the use of FIBER FILM® technology is well known in applications with liquid-liquid contactors; however, applicants are not aware of any FIBER FILM® technology that performs the separation of two immiscible liquids, such as a caustic and hydrocarbon rich in DSO. Applicants' invention also does not require any addition of solvent to effect the separation of the DSO from the oxidized caustic solution. Applicants unique in the invention is the requirement for only a single stream containing a mixture of immiscible liquids being fed to the separator device containing the bundle of fibers. No additional process current is required to effect the separation. In a specific application of the applicants' process they were able to separate DSO from the oxidized caustic solution to below 5 ppm in the caustic. Applicants' invention will also find use in reverse process applications where an acidic aqueous solution is used to extract basic compounds from a liquid, such as a hydrocarbon-based liquid. The only important factor is that only a single vessel is used and at least two immiscible liquids leaving the oxidant section are fed as a mixture in a single stream to at least one separator using fibers in suspension.
    [17] These and other objects have become more apparent from the detailed description of the preferred embodiments contained below. BRIEF DESCRIPTION OF THE FIGURES
    [18] Figure 1 schematically illustrates a possible embodiment of the process of the applicants' invention using FIBER FILM® technology to separate caustic DSO, where a small solvent stream is added before the oxidation step; Figure 2 is a graphical representation showing the effectiveness of the applicants' invention compared to a conventional gravity separator; Figure 3 shows another possible embodiment of the invention of the applicants having a design with a single tower with the oxidizer on top and two FIBER FILM® (FFS) separators in series below the oxidizer; and Figure 4 shows a schematic representation of the design of a single tower of the applicants' invention with the oxidant on top and four FIBER FILM® (FFS) separators in series below the oxidizer. DETAILED DESCRIPTION
    [19] As specified, applicants' invention relates to a new process for separating at least two immiscible liquids into a mixture using FIBER FILM® technology. A specific application of the inventors' invention relates to the treatment of hydrocarbon caustic, such as LPG to remove contaminants, such as sulfur compounds, which are detrimental to downstream processes. In particular, the inventors' invention replaces conventional sedimentators with gravity or forced separation technology, such as centrifuges, with a separation vessel employing fibers with a high surface area to separate oxidized sulfur contaminants from the caustic solution. This new use of fibers in vertical suspension with a high surface area dramatically reduces the residence time typically required for separation by an order of magnitude. In addition, applicants have found that the addition of a small solvent stream in or upstream of the oxidizer further improves the performance of the downstream separation when using FIBER FILM® technology.
    [20] Figure 1 illustrates an embodiment of the applicants' invention where a LPG feed, contaminated with mercaptan compounds, for example, ethyl mercaptide, is fed via line 1 to a caustic treatment section 3. The specific design of the caustic treatment section is not critical to the applicants' invention; however, a preferred design includes staged contactors operating in a countercurrent configuration, with a more preferred contactor configuration using fibers suspended in liquid-liquid contactors. These as well as other contactor configurations are well known to those skilled in the art. Poor caustic is fed via line 5 into the treatment section of contactor 3 where it mixes with LPG introduced via line 1. The caustic used in the applicants invention can be any type of sweetening hydrocarbons known in the art, including solutions comprising NaOH, KOH , Ca (OH) 2, Na2CÜ3, ammonia, extraction of organic acids, or mixtures thereof. Preferably, the caustic comprises aqueous potassium hydroxide solutions and aqueous sodium hydroxide solutions having a concentration of about 1% to about 50%, more preferably about 3% to about 25%, even more preferably about from 5% to about 20%, by weight of alkaline hydroxide.
    [21] Substantially sulfur-free LPG is removed from the contactor section 3 via line 7 and is used in subsequent processes, for example, in the alkylation unit. By substantially sulfur-free applicants mean that LPG has a level of <150 ppm total sulfur, preferably <20 ppm total sulfur and more preferably <10 ppm total sulfur. The caustic solution in the contactor section 3 is a caustic-rich solution that is removed via line 9. The rich caustic contains mercaptans and other sulfur contaminants extracted from the LPG feed.
    [22] The rich caustic from the caustic treatment section is then fed to oxidizer 10. As with liquid-liquid contactors, the exact design of the oxidizer is not critical to the inventors' invention and any number of oxidant designs can be used, such as bubbling oxidants, and solid catalyst technology and non-catalytic solid filling. A preferred oxidizer is one that contains a solid bed of catalyst, preferably a catalyst containing an active metal, such as cobalt, impregnated on a solid support, for example, activated carbon. A more preferred catalyst is one sold commercially by Merichem Company under the trademark ARI ™ -120L. In an alternative embodiment of the inventors' invention a small volume stream of solvent 11 is introduced into the oxidizer 10 along with the caustic-rich stream. This solvent stream can be mixed with the rich caustic before entering the oxidizer or injected as a separate stream into the oxidizer. The solvent can be any light hydrocarbon that will assist in the separation downstream of the DSO from the caustic solution after oxidation. Any relatively light hydrocarbon or mixture of such hydrocarbons can be used as a solvent in the inventors' invention, however, preferred solvents include naphtha and kerosene. Although the exact mechanism of how the solvent improves DSO separation from oxidized caustic is not specifically known, one theory is that the solvent has a much higher DSO solubility than caustic, with its solubility differentials providing an extractive drive force . This effect is further amplified by carrying out the process on a FIBER FILM® device that provides a higher interfacial surface area. The amount of solvent, based on the percentage of the caustic-rich feed, injected into the oxidant, or with the rich caustic or separately, is not particularly critical to the inventors' invention since the minimum amount is used in order to improve performance separation of the downstream stream. As mentioned, only a small volume of solvent is required, with a preferred minimum solvent injection range of about 0.1% by volume to about 10.0% by volume, preferably about 0.5% by volume. about 5.0% in volume, of rich caustic feed via line 9.
    [23] In addition to the rich caustic and solvent feeds for the oxidant, air or other oxygen-containing gas (s) is introduced into the oxidizer via line 12. The amount of oxygen-containing gas added to the oxidant is sufficient to reach 95% + oxidation of the mercaptan compounds originally present in the LPG to disulfide compounds, more preferably 99% + oxidation. A preferred range of operating conditions for the oxidizer includes a temperature of about 75 ° F (297 K) to about 200 ° F (367 K) and a caustic flow rate as high as 10 LHSV, but preferably about 100 ° F (311 K) to about 150 ° F (339 K) and less than 5 LHSV. The operational pressure of the applicants' process is not critical as it keeps the process currents in a liquid state.
    [24] The effluent from oxidant 10, or oxidized caustic, which is a mixture of caustic and DSO, is removed via line 13 from oxidant 10 and passed to separator 14 where the DSO is separated from the caustic using fibers in vertical suspension. The separator 14 can be any device that uses a column of fibers firmly filled and that provides a large surface area. As mentioned, such fiber film technology has been used in the past in liquid-liquid contactors to facilitate the mass transfer of chemical compounds from one liquid to another liquid, but with the applicants' knowledge it has never been applied alone for the purpose of separating a mixture of two or more immiscible liquids. The design of these fiber film liquid-liquid contactors has been described in several references, for example, in Pat. U.S. Nos. 3,758,404, 3,992,156, 4,666,689, 4,675,100 and 4,753,722, all of which are incorporated herein by reference for all purposes. Applicants' invention is the first to use fiber film technology in a separation application. Applicants are not using it as a liquid-liquid contactor for mass transfer. Consequently, only a single feed stream needs to be fed to the fiber bundles with a high surface area. In the specific application illustrated in Fig. 1, the mixture comprises DSO containing oxidized caustic and waste gases. The mixture is fed via the single line 13 to the separator 14. The caustic oxidized with DSO and gases enter the top of the fiber bundle 20 which comprises substantially elongated fibers mounted on a blanket and contained within a conduit. This conduit is provided with an inlet flange and a fluid distribution means for distributing the oxidized caustic with DSO from line 13 on the fibers. The fibers in the separator 14 are selected from the group consisting of, but not limited to, metal fibers, glass fibers, polymer fibers, graphite fibers and carbon fibers to satisfy two criteria: (1) the fiber material must preferably be moistened by mixing at least two immiscible liquids; and (2) the fibers must be of a material that will not contaminate the process or will be destroyed by it, such as by corrosion.
    [25] During the operation of the separator 14 two layers are formed at the bottom of the collection vessel 21; a lower layer 23 comprising the regenerated caustic solution and an upper layer 22 comprising the separate DSO. Fig. 1 also illustrates an alternative embodiment where a small stream of solvent is added upstream of oxidizer 10. When this alternative is used, the added solvent is removed along with the DSO in the top layer 22. Outlet gases are removed from the top of the collection vessel 21 vis line 15. The fiber bundle blanket and fibers extend within the confines of the separator 14, with the position of the downstream end of the fiber bundle within the collection vessel 21 being such that the downstream end ends inside the lower layer 23. The more solvent DSO in the upper layer 22 is removed from the separator vessel 14 via line 16 and sent for further storage or processing.
    [26] The residence time within the separator 14 is selected to achieve maximum removal of DSO from the caustic phase, with the target concentration being 5 ppm or less. Surprisingly, applicants have found that the use of fibers in vertical suspension, with and without the added solvent, greatly decreases the residence time required by an order of magnitude compared to a conventional gravity sedimentation device. As explained more fully in the examples below, the use of fibers in suspension reduces the residence time from approximately 90 minutes for a gravity settler to less than 5 minutes for a separator of the inventors' invention using fibers in vertical suspension. The addition of solvent as explained above further improves the separation performance as shown by the graph described in the following examples.
    [27] The rate of removal of the caustic solution in the lower layer 23 via line 17 is adjusted to maintain the correct residence time required to achieve DSO levels in this layer of 5 ppm or less measured as sulfur. The caustic solution separated in stream 17 can be further purified in a polishing unit 24, to ensure that its DSO content is less than 5 ppm. Various polishing procedures are well known in the art, most of which involve liquid-liquid contact technology. The final purified caustic is then removed from vessel 24 as poor caustic and recycled via line 5 to the caustic treatment section 3.
    [28] Figure 3 illustrates the process of the applicants' invention conducted in a single vessel where rich or used caustic 100 enters the top of the oxidizer 160 section, together with air 200 and solvent 500. The currents are combined and introduced at the top of the solid catalyst bed 350 through distributor 150. The oxidation of mercaptides to disulfide oil (DSO) occurs within catalyst bed 350, which results in a mixture consisting of continuous phase caustic, organic phase droplets (solvent + DSO) batch dispersed in the caustic phase, and gas (nitrogen and unreacted oxygen from the air). The mixture exiting oxidizer 160 enters the first blanket containing a bundle of fibers in vertical suspension with a distributor at inlet 210, which is located in section 170. Oxidant 160 gas separates from the liquid stream at the outlet of the bundle of fibers and it exits through a mist eliminator 340 as outlet gas 330. The two immiscible liquids, as a single stream, flow downwardly along the vertical fibers during which organic hydrocarbon droplets coalesce and form an organic top layer 250 , while the aqueous caustic adheres to the fibers and still flows downwards to form a caustic bottom layer 260.
    [29] A used solvent stream containing DSO 400 is removed from the organic top layer 250 within separation section 170. A caustic stream 800, with substantially reduced amount of DSO, is removed from the caustic bottom layer 260. The stream caustic 800 is further mixed with new solvent 300 to form the stream 900, and enter the second separation section 180 containing a vertical fiber bundle with a distributor at the inlet 220. The liquid stream flows downwardly along the vertical fibers during the that the remaining organic droplets coalesce and form an organic top layer 270, while the aqueous caustic adheres to the fibers and still flows downwards to form a caustic bottom layer 280. A stream of recycle solvent that contains a low content of DSO 500 is removed from the organic top layer 270 inside the separation section 180 and is recycled to the top of the oxidizer 160 vessel. Ustico 140, with a very low DSO content, is removed from the caustic bottom layer 280 inside the second separation section 180.
    [30] Figure 4 shows another embodiment of the applicants' invention where two additional FIBER FILM® (FFS) separation sections are added in a single tower to achieve even greater caustic purification. This embodiment has four stages of FFS, that is, FFS1, FFS2, FFS3 and FF4, that is, 170, 180, 190, and 200, where the solvent and caustic streams are at first countercurrent. The countercurrent flow configuration is performed by removing solvent from the FFS (n) and fed to FFS (n-l), while the caustic current flows from FFS (n-l) to FFS (n). Here n = 2, 3, 4, refers to FFS2, FFS3, and FFS4. A used solvent stream containing DSO 400 is removed from the organic top layer 250 inside section FFS1 170. The caustic stream 800 is mixed with the recycling solvent 600 from the third separation section 190 to form the stream 900, and enters in the second separation section 180 containing a vertical fiber bundle with a distributor at the entrance 220. The third separation section 190 contains a vertical fiber bundle with a distributor at the entrance 230 and has an organic top layer 290 inside the FFS3 and a caustic bottom layer 300. A stream of recycle solvent with a low DSO 500 content is removed from the organic top layer 270 inside section FFS2 180 and is recycled to the top of the oxidizer vessel 160. The caustic stream 120 it is mixed with new solvent 3000 to form the stream 130, and enters the fourth separation section 200 containing a vertical fiber bundle with a distributor at the inlet 240. A stream regenerated or low in caustic 14 0, with little or no DSO, is removed from the caustic bottom layer 320 within the FFS4 section 200. EXAMPLE
    [31] To demonstrate the surprising and unexpected performance of the applicants 'invention, laboratory tests were performed to compare a conventional gravity sedimenter (CGS) with the high surface area fiber separator of the applicants' invention. A 2.54 cm (1 in) diameter oxidizer charged with the solid catalyst ARI-120L was used to oxidize a caustic-rich solution containing about 7000 ppm of ethyl mercaptide sulfur to a conversion level of 99% + at a temperature of about 125 ° F (325 K), 4.0 LHSV and manometric back pressure of 1.75 kg / cm2 (17,375 N / m2 or 25 psig). Air was injected at about 300 ml / min. In separate tests, kerosene was injected into the oxidant at a rate of 1.5 ml / min.
    [32] The oxidant effluent containing about 7000 ppm of sulfur in the DSO as diethyl disulfide was first fed into a 7.62 cm (3 in) diameter CGS and left to sediment by gravity. After 5 and 90 minutes of residence time, the level of DSO in the caustic dropped to about 76 and 6 ppm, respectively (Figure 2).
    [33] The CGS was then replaced by a FIBER FIEM® separator, with the fibers providing an extremely large surface area. The FIBER FIEM® separator contained 150 metal fibers in a blanket placed within a 3/8 inch (9.5 mm) conduit. The same adjustment was used when the solvent injection into the oxidant was performed.
    [34] The graph shown in Figs. 2 shows the comparison of the FIBER FILM® separator with CGS. With CGS, the caustic contained 76 ppm DSO with a residence time of 5 minutes. Surprisingly, the FIBER FILM® separator of the inventors' invention produced a DSO content of only 12 ppm with the same residence time of 5 minutes.
    [35] The effect of adding 5% by volume of solvent (such as kerosene) to the oxidant is also shown in Fig. 2. The solvent injection combined with the FIBER FILM® separation reduced the DSO content to 4 ppm with a residence time of 5 minutes.
    [36] The foregoing description of specific embodiments will reveal so completely the general nature of the invention that others can, by applying current knowledge, quickly modify and / or adapt such forms of specific achievements for various applications without deviating from the generic concept, and for this reason, such adaptations and modifications are planned to be understood within the meaning and range of equivalents of the forms of realization. It should be understood that the phraseology and terminology here are for the purpose of description and not limitation.
    [37] The means, materials, and steps for carrying out the various functions described can take a variety of alternative forms without deviating from the invention. Thus, the expressions "means of ..." and "means for ...", or any language of the method step in the application above or in the claims below, followed by a functional specification, are designed to define and cover any structure or electrical, chemical, physical or structural element, or any stage of the method, which may exist now or in the future that performs the aforementioned function, whether or not precisely equivalent to the embodiment or embodiments described in the application above, that is, other means or steps to perform the same function can be used; and it is planned that such expressions will be given their broadest interpretation within the terms of the following claims.
    权利要求:
    Claims (6)
    [0001]
    1. Process for the oxidation of mercaptan compounds in a caustic-rich stream and separation of disulfide oil from the caustic-rich stream to generate a sulfur-free caustic stream, characterized by the fact that it comprises, in combination, a) feed solvent, an oxygen-containing fluid, and a caustic-rich stream containing mercaptan compounds to a single tower having a top section (160) containing an oxidizer and a bottom section containing at least two contactors (170, 180) comprising fibers in series below the oxidant, in which the caustic-rich stream is obtained from a separation process that separated hydrocarbons from the caustic-rich stream and the mercaptan compounds in the caustic-rich stream were extracted from the hydrocarbons; b) contact the current from step a) with a catalyst in the oxidizer to oxidize the mercaptan compounds to disulfide oil (DSO) with a conversion level of 90% or greater in the presence of oxygen and form a mixture comprising DSO, solvent, and caustic; c) directing the mixture formed in step b) from the oxidizer as a single stream to a first separation section (170) within the single tower where the mixture comes into contact with a bundle of fibers in vertical suspension; d) separating the DSO and the caustic solvent within the first separation section by allowing the mixture to flow through the fiber bundle to form two distinct liquid layers, a first lower layer (260) comprising a caustic phase and a first upper layer (250) comprising a DSO / solvent phase, in a first collection zone; e) continuously removing a portion of the DSO / solvent phase (400) from the first separation zone; f) continuously remove a portion of the caustic phase (800) and mix with new solvent (300) to form a second separation feed (900) which is fed to a second separation section (180) within the single tower where it enters in contact with a second bundle of fibers in vertical suspension; g) separating any remaining DSO and caustic solvent within the second separation section by allowing the second separation feed to flow through the fiber bundle in the second separation section to form two distinct liquid layers, a second lower layer (280) comprising a phase caustic and a second top layer (270) comprising a DSO / solvent phase, in a second collection zone; h) continuously removing a portion of the DSO / solvent phase (500) from the second separation zone and recycling it as the solvent from step a); and i) continuously removing a caustic-poor stream (140) from the second lower layer.
    [0002]
    Process according to claim 1, characterized in that the caustic-rich stream containing mercaptan compounds is oxidized by bringing the stream into contact with a solid bed (350) containing a metal supported catalyst.
    [0003]
    Process according to claim 1, characterized by the fact that residual gas is removed as the outlet gas (330) in the first separation section.
    [0004]
    4. Unique tower to treat a caustic-rich stream containing mercaptan compounds, characterized by the fact that it comprises, a) an upper section (160) comprising an oxidizer; and b) a lower section comprising at least two separation sections (170, 180) of series flow, where each separation section contains a fiber mat in vertical suspension and a liquid collection zone. 2> π
    [0005]
    5. Countercurrent process to oxidize mercaptan compounds in a caustic-rich stream and separate disulphide oil from the caustic-rich stream to generate a sulfur-free caustic stream, characterized by the fact that it comprises, in combination, a) solvent feed, an oxygen-containing fluid, and a caustic-rich stream containing mercaptan compounds for a single tower having a top section (160) containing an oxidizer and a bottom section containing at least three separation sections (170, 180, 190) containing contactors comprising fibers in series below the top section, in which the caustic-rich stream is obtained from a separation process that separated hydrocarbons from the caustic-rich stream and the mercaptan compounds in the caustic-rich stream were extracted from the hydrocarbons; b) contact the current of step a) with a catalyst in the oxidizer to oxidize the mercaptan compounds to disulfide oil (DSO) with a conversion level of 90% or greater in the presence of oxygen and form a mixture comprising DSO, solvent , and caustic; c) directing the mixture formed in step b) from the oxidizer as a single stream to a first separation section (170) within the single tower where the mixture comes into contact with a bundle of fibers in vertical suspension; d) separating the DSO and the caustic solvent within the first separation section by allowing the mixture to flow through the fiber bundle to form two distinct liquid layers, a first lower layer (260) comprising a caustic phase and a first upper layer (250) comprising a DSO / solvent phase, in a first collection zone; e) continuously removing a portion of the DSO / solvent phase (400) from the first separation section; f) continuously removing a portion of the caustic phase (800) and mixing with a DSO / solvent stream (600) removed from a third separation section (190) to form a second separation feed which is fed to a second separation section (180) inside the single tower where it comes in contact with a second bundle of fibers in vertical suspension; g) separating any remaining DSO and caustic solvent within the second separation section by allowing the second separation feed to flow through the fiber bundle in the second separation section to form two distinct liquid layers, a second lower layer (280) comprising a phase caustic and a second top layer (270) comprising a DSO / solvent phase, in a second collection zone; h) continuously removing a portion of the DSO / solvent phase (500) from the second separation section and recycling it as the solvent from step a); ei) continuously remove a caustic current from the second lower layer (1000) and mix with new solvent to form a third separation feed which is fed to a third separation section (190) within the single tower where it comes in contact with a third bundle of fibers in vertical suspension; j) separating any remaining DSO and caustic solvent within the third separation section by allowing the third separation feed to flow through the fiber bundle in the third separation section to form two distinct liquid layers, a third lower layer comprising a caustic phase (300 ) and a third upper layer (290) comprising a DSO / solvent phase, in a third collection zone; k) continuously removing a portion of the DSO / solvent phase from the third collection zone to be mixed with the caustic phase in step f); and l) continuously removing a low caustic stream from the lower third layer in the third collection zone.
    [0006]
    6. Countercurrent process to oxidize mercaptan compounds in a caustic-rich stream and separate disulphide oil from the caustic-rich stream to generate a sulfur-free caustic stream, characterized by the fact that it comprises, in combination, a) solvent feed, an oxygen-containing fluid, and a caustic-rich stream containing mercaptan compounds for a single tower having a top section (160) containing an oxidizer and a bottom section containing at least four separation sections (170, 180, 190, 200) containing contactors comprising fibers in series below the top section, in which the caustic-rich stream is obtained from a separation process that separated hydrocarbons from the caustic-rich stream and the mercaptan compounds in the caustic-rich stream were extracted from the hydrocarbons ; b) contact the current of step a) with a catalyst in the oxidizer to oxidize the mercaptan compounds to disulfide oil (DSO) with a conversion level of 90% or greater in the presence of oxygen and form a mixture comprising DSO, solvent , and caustic; c) directing the mixture formed in step b) from the oxidizer as a single stream to a first separation section (170) within the single tower where the mixture comes into contact with a bundle of fibers in vertical suspension; d) separating the DSO and the caustic solvent within the first separation section by allowing the mixture to flow through the fiber bundle to form two distinct liquid layers, a first lower layer (260) comprising a caustic phase and a first upper layer (250) comprising a DSO / solvent phase, in a first collection zone; e) continuously removing a portion of the DSO / solvent phase (400) from the first separation section; f) continuously removing a portion of the caustic phase (800) from the first collection zone and mixing with a DSO / solvent stream (600) removed from a third separation section (190) to form a second separation feed that is fed to a second separation section within the single tower where it comes in contact with a second bundle of fibers in vertical suspension; g) separating any remaining DSO and caustic solvent within the second separation section by allowing the second separation feed to flow through the fiber bundle in the second separation section to form two distinct liquid layers, a second lower layer (280) comprising a phase caustic and a second top layer (270) comprising a DSO / solvent phase, in a second collection zone; h) continuously removing a portion of the DSO / solvent phase (500) from the second separation section and recycling it as the solvent from step a); i) continuously remove a caustic stream from the second lower layer (1000) and mix with a DSO / solvent stream (700) removed from a fourth separation section to form a third separation feed which is fed to a third separation section ( 190) inside the single tower where it comes into contact with a third bundle of fibers in vertical suspension; j) separating any remaining DSO and caustic solvent within the third separation section by allowing the third separation feed to flow through the fiber bundle in the third separation section to form two distinct liquid layers, a third lower layer (300) comprising a phase caustic and a third upper layer (290) comprising a DSO / solvent phase, in a third collection zone; k) continuously removing a portion of the DSO / solvent phase from the third collection zone to be mixed with the caustic phase in step f); l) continuously remove a caustic current from the lower third layer in the third collection zone and mix with new solvent to form a fourth separation feed that is fed to a fourth separation section (200) within the single tower where it comes in contact with a fourth bundle of fibers in vertical suspension; m) separating any remaining DSO and caustic solvent within the fourth separation section by allowing the fourth separation feed to flow through the fiber bundle in the fourth separation section to form two distinct liquid layers, a lower fourth layer (320) comprising a phase caustic and a fourth upper layer (310) comprising a DSO / solvent phase, in a fourth collection zone; n) continuously removing a portion of the DSO / solvent phase (700) from the fourth collection zone to be mixed in the caustic phase in step i); and o) continuously removing a low caustic stream from the lower fourth layer in the fourth collection zone.
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    同族专利:
    公开号 | 公开日
    US20130026086A1|2013-01-31|
    US8308957B2|2012-11-13|
    EP2600955A1|2013-06-12|
    EP2600955B1|2016-02-24|
    CN103189117A|2013-07-03|
    HK1182043A1|2013-11-22|
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    TWI422423B|2014-01-11|
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    EA201400770A1|2015-02-27|
    US20100320124A1|2010-12-23|
    TW201206552A|2012-02-16|
    BR112013001954B8|2020-12-15|
    JP2013536280A|2013-09-19|
    WO2012018657A1|2012-02-09|
    US8454824B2|2013-06-04|
    ES2572941T3|2016-06-03|
    CN103189117B|2015-02-18|
    JP5714109B2|2015-05-07|
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    法律状态:
    2018-05-29| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2019-04-24| B06T| Formal requirements before examination|
    2020-04-07| B09A| Decision: intention to grant|
    2020-11-03| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 27/07/2011, OBSERVADAS AS CONDICOES LEGAIS. |
    2020-12-15| B16C| Correction of notification of the grant|Free format text: REF. RPI 2600 DE 03/11/2020 QUANTO A PRIORIDADE UNIONISTA E O WO. |
    优先权:
    申请号 | 申请日 | 专利标题
    US12/849,408|US8308957B2|2007-06-14|2010-08-03|Process for separating mercaptans from caustic|
    PCT/US2011/045544|WO2012018657A1|2010-08-03|2011-07-27|Separation process|
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