System and method to produce polymer grade propylene from unsaturated LPG using a single column

Abstract

A separation process and system to separate highly pure polymer grade propylene product from a liquefied petroleum gas stream combined. In examples, the system and method as combine the functions of a deethanizer and of a depropanizer, with a C3 splitter system to separate highly pure polymer grade propylene product from a liquefied petroleum gas stream, thus eliminating the need for separate dethanizer, depropanizer, and C3-splitter.

Description

SYSTEM AND METHOD TO PRODUCE POLYMER GRADE PROPYLENE FROMUNSATURATED LPG USING A SINGLE COLUMN

[0001] This application claims the benefit of Indian Patent Application No. IN202311045057, filed on July 5, 2023, which is hereby incorporated by reference for all purposes as if fully set forth herein.BACKGROUNDField of the Disclosure

[0002] The present disclosure relates to a separation process and system. In particular, the system and method may separate highly pure polymer grade propylene product from a liquefied petroleum gas stream combined. In examples, the system and method as described combine the functions of a deethanizer column and of a depropanizer column, with a C3 splitter system.Discussion of the Related Art

[0003] Polymer grade propylene (PGP) is a high-purity form of propylene primarily used as a feedstock in the production of polypropylene, which is one of the most widely used plastics. Polypropylene has various applications due to its versatility, durability, and resistance to chemicals and heat. The PGP has stringent specifications and its purity requirement in the industry varies from 99.5%(vol) to 99.8%(vol).

[0004] PGP is generally recovered from liquefied petroleum gas (LPG). The process typically requires multiple sequential distillation columns to achieve the high-purity level andoptimum recovery of propylene from treated unsaturated gas. Known systems employ two or three distillation columns. A two-column system typically includes a depropanizer column followed by a C3-splitter column. A three-column system ty pically includes a depropanizer column, followed by a dethanizer column, followed by a C3-splitter column.

[0005] FIG. 1 illustrates a conventional multiple column system 100. In the illustrated example, the scheme includes three distillation columns. As shown, a treated LPG stream 102 is fed to a multiple distillation columns system including a depropanizer column 110, a deethanizer column 120 downstream the depropanizer column 110, and a C3-splitter column 130 downstream the deethanizer column 120. As illustrated, each column may include respective condenser and reboiler systems 116, 118, 126, 128, 136, and 138 respectively. The depropanizer column 110 is typically configured to remove propane and lighter for the treated LPG stream. As shown, a product stream of C4 (butane and butenes) and higher hydrocarbons if present (collectively referred to as “C4+”), may be removed as a bottoms product stream 114 of depropanizer column 110. The overhead stream 112 of the depropanizer column 1 10 is then typically fed to the deethanizer column 120 to remove the light ends C2 (ethane and ethylene) via overhead stream 122 with a portion being directed to an off-gas system. The C3-rich stream from the bottoms product stream 124 of the deethanizer column 120 is instead fed to a C3-splitter column 130 that is configured to separate the PGP product from the propane product. As illustrated, the overhead stream 132 of C3 -splitter column 130 will exhaust the remaining light ends and direct them to an off-gas system. A side draw 140 is used to provide a PGP product stream, while the botoms product stream 134 of C3-spliter column 130 provides a propane product stream.

[0006] Although effective, multiple column systems require high capital investments and require large plot spaces because of the multiple columns and other ancillary7equipment. Also, multiple column system tend to be energy inefficient due to the remixing effect.

[0007] Thus, there is a need for improved systems that can provide advantages over the processes and equipment currently available.SUMMARY

[0008] Examples of system and method to produce PGP from unsaturated LPG using a single column can substantially obviates one or more of the problems due to limitations and disadvantages of the related art or at least to provide the public with a useful alternative.

[0009] Examples as described herein can provide a more energy efficient system and method as compared to what is currently available.

[0010] Examples as described herein can lead to reduced capital investment as compared to what is currently available.

[0011] Examples as described herein can require lesser plot space as compared to what is currently available.

[0012] Additional features and advantages of the examples as described herein will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the disclosure. The objectives and other advantages of the disclosure will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0013] In examples, described herein may be a process for recovery7of polymer grade propylene from liquified petroleum gas (LPG) that may include feeding and LPG stream to a pre-fractionating section of a dividing wall column; and producing by the dividing wallcolumn a polymer grade propylene product stream and a propane product stream, wherein, the polymer grade propylene product stream may be obtained as an overhead stream or as a side draw stream.

[0014] In examples, the process may include producing a light ends stream and a C4+ containing stream.

[0015] In examples, the light ends stream may be produced as an overhead stream, the polymer grade propylene product stream may be produced may be a first side draw stream, the propane product stream may be produced as a second side draw stream, and the C4+ containing stream may be produced as a bottoms product stream.

[0016] In examples, the first side draw stream may be drawn below the overhead stream, and the second side draw stream may be drawn below' the first side draw stream.

[0017] In examples, the second side draw stream may be drawn from a main fractionation section of the dividing w all column.

[0018] In examples, the light ends stream may be produced as a first overhead stream, the polymer grade propylene product stream may be produced may be a second overhead stream, the propane product stream may be produced as a side draw' stream, and

[0019] the C4+ containing stream may be produced as a bottoms product stream.

[0020] In examples, the draw stream may be drawn from a main fractionation section of the dividing w'all column.

[0021] In examples, the process may include passing at least a portion of the bottoms product stream to reboiler and extracting the remaining portion.

[0022] In examples, the process may include directing the polymer grade propylene product stream to a first storage unit and directing the propane product stream to a second storage unit.

[0023] In examples, described herein is a dividing wall column for production of polymer grade propylene from Liquified Petroleum Gas (LPG) that may include one or more dividing walls in the dividing wall column and configured to define a pre-fractionating section and a main fractionation section inside the dividing wall column; an LPG feed configured to input LPG feed at the pre-fractionating section; one or more overhead streams; one or more side draw7streams that may include a propane product side draw stream drawn from the main fractionation section of the dividing wall column; a bottoms product stream; and a reboiler system configured to heat and recycle to the dividing wall column at least a portion of the bottoms product stream.

[0024] In examples, the one or more dividing walls may include two dividing walls located at different heights within the dividing wall column.

[0025] In examples, at least one of the one or more dividing walls may extend down from a top end of the dividing w all column.

[0026] In examples, one dividing wall may at least partially overlap with another dividing wall.

[0027] In examples, the one or more overhead streams may include an overhead stream of light ends.

[0028] In examples, the one or more side draw streams may include a propylene grade polymer product stream drawn below the one or more overhead streams.

[0029] In examples, the one or more overhead streams may include a first overhead stream and a second overhead stream, wherein one of the first overhead stream or the second overhead stream may include a propylene grade polymer product stream.

[0030] In examples, the dividing wall column may include a condenser system for each overhead stream of the one or more overhead streams.

[0031] In examples, the dividing wall column may include an overhead recycle line for each of the one or more overhead streams, each overhead recycle line configured to recycle at least a portion of the respective overhead stream.

[0032] In examples, described herein is a scheme for producing polymer grade propylene from Liquified Petroleum Gas (LPG) that may include a single distillation column, wherein the single distillation column is a dividing wall column that may include one or more dividing walls in the dividing wall column and configured to define a pre-fractionating section and a main fractionation section inside the dividing wall column; an LPG feed configured to input LPG feed at the pre-fractionating section; one or more overhead streams; one or more side draw streams that may include a propane product side draw stream drawn from the main fractionation section of the dividing wall column; and a bottoms product stream.

[0033] Any combination of the above-listed features may be implemented without departing from the spirit or scope of this disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the descnption serve to explain the principles of the disclosure.

[0035] In the drawings:

[0036] FIG. 1 depicts a conventional system for fractionating a LPG fluid using a deethanizer, a depropanizer, and a C3 splitter for producing PGP as presently available in the art.

[0037] FIGS. 2 and 3 depict examples of an illustrative system and method for fractionating LPG fluid in accordance to the present disclosure.DETAILED DESCRIPTION

[0038] In examples, disclosed are a process and system for recovery of PGP from LPG. In examples, the process and system may include a scheme having a single column that can achieve the same recovery, quality, and high-purity of PGP that is achieved by operating multiple columns in sequence. As previously stated, high-purity' of PGP refers to a purity’ of at least 99% (vol), for example from about 99.5%(vol) to about 99.8%(vol). In examples, the single column may include a dividing wall column.

[0039] In examples, the single column scheme as described herein may provide significant advantages in comparison with conventional multiple sequential distillation columns to produce high purity propylene from LPG. As used herein, the term “single” referring to the column of the scheme described herein is intended to mean that the scheme does not include any other distillation column is used to distill PGP from an LPG feed stream. In examples, the single column scheme as described herein may require lesser energy and lesser capital investment, and / or lesser plot space as compared to conventional schemes. In examples, the scheme may separate PGP from all other components using a single column whereas conventional scheme might employ three columns in sequence to achieve same level of separation. Hence the subject invention helps in saving plot area. In examples, the scheme as described may employ only one condenser and reboiler as compared to convention scheme where each column of the multiple column system typically includes its own condensing andreboiling system. Hence, this scheme as described may be less capital intensive. In examples, the total no of trays in the scheme as described herein may be less than the cumulative number of trays required in conventional three column system. Hence the scheme as described herein may be less capital intensive than a multiple column system. Also, in examples, the scheme as described herein may require less reboiling and condensing duty than that of a conventional three column system which means lower utility consumption and therefore lower operating costs.

[0040] In examples, the single column may include a fractionation column. As used herein, the term “fractionation column” can refer to any system, device, or combination of systems and / or devices suitable for the selective separation of a mixture containing two or more components having differing boiling points. In examples, a fractionation column may include a distillation column, a rectification column, a stripping column, a splitter column, and the like.

[0041] In examples, the single column may include a dividing wall column, i.e. a column that includes one or more dividing walls. In examples, the single column may include a fractionation column having one or more dividing walls provided therein. For purposes of this description, a diving wall column refers to a column that includes a “dividing wall” which refers to any partition plate provided within an interior space of a column to provide different sections within the column. In examples, the dividing wall in the dividing wall column may separate the space inside the dividing wall column to provide a first fractionation section or pre-fractionating section on one side of the wall and a second fractionation section or main fractionation section on the other side of the wall. The dividing wall can be either segmented or continuous. The dividing wall can be parallel or non-parallel relative to the longitudinal axis of the column. The first fractionation section and the secondfractionation section can have the same or different cross-sectional areas, volumes, or both. In one or more specific embodiments, the column can have a circular cross-section and the dividing wall can bisect the cross-section of the column to provide equal cross-sectional areas within the first fractionation section and the second fractionation section. In examples, a stripping zone may be present at least below the pre-fractionating section.

[0042] In examples, the single column may include one partition plate or dividing wall. In examples, single column may include more than one partition plates or dividing walls, for example two partition plates or dividing walls. In examples, a partition plate or dividing wall may be located at lower portion of the single column, at a middle portion of the single column, or at a top portion of the single column. In examples, a partition plate or dividing wall may extend across more than one portion of the single column. In examples, where the single column includes more than one partition plate or dividing wall, the partition plates or dividing walls may be located at different heights in the single column.

[0043] In examples, a treated LPG stream can be received at the prefractionating section of the dividing wall column where various hydrocarbon components are separated by distillation. The partition plate in the dividing wall column may be configured to restrict the mixing of the fluid on the two sides of the plate which may include different composition. In examples, this can make the distillation process more energy efficient.

[0044] In examples, the dividing wall column may be configured to separate treated unsaturated LPG into multiple streams. In examples, the dividing wall column may be configured to heat and separate the LPG into four streams, a light ends stream, a PGP product stream, a propane product stream, and a C4+ product stream.

[0045] In examples, the light ends stream may include lighter compounds such as ethane and ethylene. In examples, the light ends stream may be removed from the top of the column. In examples, removal of the light ends stream may help in meeting the light end specification of PGP.

[0046] In examples, the PGP may be drawn via a first side draw located a few trays below the top tray of the column. In examples, the trays between the overhead stream and the PGP draw can help ensure the desired separation of light ends from the PGP product. In examples, the first side draw product stream may be recovered as a main product and directed to a first storage unit.

[0047] In examples, propane can be concentrated in main fractionation section of the dividing wall column. In examples, a second side draw is taken out from an appropriate location below the first side draw to yield a propane product stream. In examples, the second side draw product stream may be directed to a second storage unit.

[0048] In examples, the C4+ components may be withdrawn from the bottom of the main fractionation section of the dividing wall column as a bottoms product stream. In examples, at least a portion of the bottoms product stream of the main fractionation of the dividing wall column may be passed to a reboiler and recycled to the dividing wall column. In this manner, it may be possible to transfer heat to the bottom portion of dividing wall column. In examples, the remaining portion of the bottoms product stream that is not passed to a reboiler may be extracted as a bottoms product.

[0049] In this manner, in the process and system as described herein the function of a depropanizer column, a deethanizer column and of a C3-splitter column, that are typically found in multiple column schemes can be integrated in a single diving wall column. Thissingle column scheme can be more energy efficient than the conventional multiple column schemes.

[0050] Reference will now be made in detail to one or more examples, which are illustrated in the accompanying drawings.

[0051] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which the disclosures belong. All patents, patent applications, published applications and publications, websites and other published materials referred to throughout the entire disclosure herein, unless noted otherwise, are incorporated by reference in their entirety. Where there is a plurality of definitions for terms herein, those in this section prevail. Where reference is made to a URL or other such identifier or address, it is understood that such identifiers can change and information on the internet can come and go, but equivalent information can be found by searching the internet. Reference thereto evidences the availability and public dissemination of such information.

[0052] As used herein, the singular forms '‘a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0053] The terms first, second, third, etc. as used herein can describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer, or section. Terms such as “first”, “second”, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below could be termed a second element,component, region, layer, or section without departing from the teachings of the example embodiments.

[0054] As used herein, ranges and quantities can be expressed as “about’' a particular value or range. “About” also includes the exact amount. Hence “about 5 percent” means about 5 percent in addition to 5 percent. The term “about” means within typical experimental error for the application or purpose intended.

[0055] As used herein, “and / or” includes any and all combinations of one or more of the associated listed items.

[0056] As used herein, a “combination” refers to any association between two items or among more than two items. The association can be spatial or refer to the use of the two or more items for a common purpose.

[0057] As used herein, “comprising” and “comprises” are intended as open-ended to be interpreted to mean “including but not limited to” and “includes but not limited to”, respectively to thus include not only the recited elements, but further encompassing any additional elements.

[0058] As used herein, “optional” or “optionally” means that the subsequently described event or circumstance does or does not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. For example, an optional component in a system means that the component may be present or may not be present in the system.

[0059] As used herein, “substantially” means “being largely but not wholly that which is specified.”

[0060] FIGS. 2 and 3 illustrate examples of the single column scheme as described herein. In examples, the illustrated examples may integrate the function of a deethanizer, adepropanizer, and a C3-spliter into a single dividing wall column for the production of PGP.In examples, the single diving wall column may be a C3 splitter dividing wall column. In examples, the location and number of partition plates or dividing walls within the column may be modified. In examples, the partition plate or dividing wall may be located at a middle or lower portion of the single column. In examples, two or more partition plates one located at different elevations of the single column may be implemented.

[0061] FIG. 2 illustrates an example where the dividing wall column may include a partition plate in a central portion thereof.

[0062] As illustrated in FIG. 2, in a scheme 200 may include a single dividing wall column 202 including one or more trays 204 and a partition plate or dividing wall 206 defining a pre-fractionating section 208 and a main fractionation section 210.

[0063] In examples, the single dividing wall column 202 may be configured to separate treated unsaturated LPG into four streams. In examples, the four streams may include a light ends stream, a PGP stream, a propane stream, and C4+ stream.

[0064] In examples, a treated unsaturated LPG feed stream 212 may be fed to the prefractionating section 208 of a dividing wall column 202. In examples, the single dividing wall column 202 may be configured to produce an overhead stream 214, a first side draw stream 216, a second side draw stream 218, and a bottoms product stream 220.

[0065] In examples, the lighter compounds such as ethane and ethylene may be removed from the top of the column via overhead stream 214. In examples, by removing the lighter compounds, it may be possible to meet the light end specification of PGP. As illustrated, the single dividing wall column 202 may include a condenser system 226. In examples, condenser system 226 may include one or more cooler or cooling systems, one or more pumps, and one or more reflux drums. In examples, the condenser system 226 may beconfigured to include one or more recycle lines configured to recycle portion 228 of overhead stream 214 is directed back to a top portion of the single dividing wall column 202, while another portion 230 may be directed to an off-gas system.

[0066] In examples, the first side draw stream 216 may be below the overhead stream 214. In examples, the first side draw stream 216 may include a PGP product stream. In examples, the first side draw stream 216 may be located a few trays 204 below the overhead stream 214. In examples, the number of trays between the overhead stream 214 and the first side draw stream 216 should be sufficient to ensure the desired separation of lighters compound from the PGP product stream. In examples, between 3 and 9 trays 204 should be provided between the overhead stream 214 and the first side draw stream 216 stream. For example, between the overhead stream 214 and the first side draw stream 216 stream there may be 3 trays, 4 trays, 5 trays, 6 trays, 7 trays, 8 trays, 9 trays, or any range of trays defined by these any two of these examples. In examples, PGP containing the first side draw stream 216 may be directed to a first storage unit 222.

[0067] In examples, the second side draw stream 218 may be located below the first side draw stream 216. In examples, the second side draw stream 218 may include the propane component of the LPG feed. In examples, the propane component is concentrated in main-fractionation section 210 of the single dividing wall column 202. Accordingly, in examples, the second side draw stream 216 may be drawn from the main fractionation section 210 of the dividing wall column 202. In examples, the location of the side draw stream 216 may be at an appropriate location along the main-fractionation section 210 to obtain the desired propane product purity. In examples, the second side draw stream 218 may be directed to a second storage unit 224.

[0068] The C4+ and heavier components may be withdrawn from dividing wall column 202 via the bottoms stream 220. In examples, the dividing wall column may include a reboiler system 342 that recycles back to the column.

[0069] In the proposed scheme the function of a depropanizer column, a deethanizer column, and of a C3-splitter column can thus be integrated in a single diving wall column. This single column scheme can be more energy7efficient than the conventional scheme.

[0070] In examples, a single dividing wall column may include multiple partition plates or dividing walls. In examples, the partition plates or dividing walls may be arranged at different heights within the single dividing wall column. In examples, the different partition plates or dividing walls may at least partially overlap or be present at the same height inside the single dividing wall column.

[0071] Illustrated in FIG. 3 is a scheme 300 including a dividing wall column 302 that may include one or more trays 304, a first partition plate or dividing wall 306, and a second partition plate or dividing wall 308. As shown, the first partition plate or dividing wall 306 and the second partition plate or dividing wall 308 may be at different heights in the single dividing wall column 302. In the example illustrated in FIG. 3, the first partition plate or dividing wall 306 may be located at a top section or portion of the dividing wall column and a second partition plate 308 at a central portion of the dividing wall column 302. In examples, the first partition plate or dividing wall 306 may extend downward from a top end of the dividing wall column 302. In examples, as shown, the first partition plate or dividing wall 306 and the second partition plate or dividing wall 308 may at least partially overlap or be provided at a same height within the single dividing wall column. In examples, the second partition plate or dividing wall 308 does not reach the bottom end of the dividing wall column302. In examples, the first partition plate or dividing wall 306 and the second partition plateor dividing wall 308 may define a pre-fractionating section 310 and a main fractionation section 312 in the single dividing wall column 302.

[0072] In examples, a treated LPG feed stream 314 may be passed to prefractionating section 310 of a dividing wall column 302 to produce a first overhead stream 316, a second overhead stream 318, a side draw stream 320, and a bottoms stream 322.

[0073] In examples, as shown in FIG. 3, the first overhead stream 316 and the second overhead stream 318 may be provided on different sides of top portion of the dividing wall column 302 as defined by the first partition plate or dividing wall 306. For example, the first overhead stream 316 may be drawn from the top of the dividing wall column 302 at a first side of first partition plate or dividing w all 306, w hile the second overhead stream 318 may be drawn from the top of the dividing w all column 302 at a second side of first partition plate or dividing wall 306. In examples, one overhead stream may contain light ends such as C2, e.g. ethane and / or ethylene, while the other overhead stream may contain PGP. In the illustrated example, the first overhead stream 316 may include light ends at least a portion of which may be directed to an off-gas system. In examples, the second overhead stream 318 may include PGP, at least a portion of w hich may be directed to a first storage unit 324.

[0074] In examples, a dividing wall column having multiple partition plates or dividing walls and including a first overhead stream and a second overhead stream may include a condenser system for each of overhead stream. In examples, each condenser system may include one or more condensers, reflux drums, pumps, and recycle lines. In examples, a portion of the overhead stream may be recycled to the dividing wall column. For example, as illustrated in FIG. 3, the dividing wall column 302 may include a first condenser system 326 and a second condenser system 328. In examples, the first overhead stream 316 may pass through the first condenser system 326. In examples, the first condenser system326 may include one or more recycle lines 330 configured to recycle at least a portion of the first overhead stream 316 may be recycled to the dividing wall column 302. In examples, at least a portion 332 of the first overhead stream 316 may be sent to an off-gas system. In examples, the second overhead stream 318 may pass through the second condenser system 328. In examples, the second condenser system 328 may include one or more recycle lines 334 configured to recycle at least a portion of the second overhead stream 318 to the dividing wall column 302. In examples, at least a portion 336 of the second overhead stream 318 may be sent to the first storage unit 324.

[0075] In examples, the side draw stream 320 may be draw n from a main fractionation section of the dividing w all column 302. In examples, the side draw stream 320 may be used to draw a propane product stream. In examples, the side draw- stream 320 may be provided anywhere along the main fractionation section depending on the level of purity desired. In examples, the side draw stream 320 may be directed to a second storage unit 338.

[0076] In examples, the bottoms product stream 322 may contain C4+ and heavier products. In examples, bottoms product stream 322 may be directed to a third storage unit 340. As illustrated in FIG. 3, the dividing wall column may include a reboiler system 342. A reboiler system may include a heater or heating system. In examples, a portion of the bottoms product stream may be drawn and passed through the reboiler system 342 and recycled to dividing wall column 302.

[0077] In examples, the condenser of the one or more condenser systems may use a cooling medium or fluid such as cooling water to cool the overhead stream passing therethrough. In examples, the heater or heating systems of the one or more reboilers may use a heating fluid or medium to heat the bottoms product stream that passes therethrough.

[0078] In examples, as described above with reference to FIGS. 2 and 3, the scheme as described herein may include a single dividing wall column to separate PGP from other components of an LPG feed more efficiently in terms of energy than conventional scheme which employs multiple columns, e.g. three columns, in sequence to achieve the same level of separation. Hence the scheme as described may help in saving plot area.

[0079] In examples, the scheme as described may employ only one condenser and one reboiler as compared to convention scheme where each column has its own condensing and reboiling system. Hence, this scheme may be less capital intensive.

[0080] In examples, the total no of trays in the scheme described herein may be less that the cumulative number of trays required in conventional three column system. This also may prove the dividing wall column as described herein to be less capital intensive.

[0081] In examples, the scheme as describes may require less reboiling and condensing duty than that of conventional three column system. In examples, the reboiler duty may be reduced by more than 10% using the system as described herein compared to a known three column system. Hence the scheme described herein may exhibit less utility consumption and therefore lower operating cost.

[0082] In examples, the systems described herein including the single dividing wall column may include one or more control systems, sensors, and other standard components that allows for the control and operation thereof.

[0083] In examples, although not shown, the systems described herein may include one or more sensors as generally employed in the art. In examples, sensors may be used to monitor the operation of the systems described. Non-limiting examples of one or more sensors may include temperature sensors, pressure sensors, flow meters, and other like sensors.

[0084] In examples, although not shown, the one or more control systems may include one or more controllers and / or other suitable computing devices may be employed to control one or more of portions of system described herein. The controls systems may include any number of logical, programmatic, and physical components. In examples, controllers may include one or more processors and memory communicatively coupled with each other. In examples, one or more input / output devices such as monitors, keyboards, speakers, microphones, computer mouse and the like may be coupled to the one or more controllers. In examples, the one or more controllers may include one or more communication elements such as receivers, transmitters, transceivers or like structure to enable wired and / or wireless communication.

[0085] In examples, memory associated with the one or more controllers and / or other suitable computing devices may be non-transitory computer-readable media. Any suitable memory technology may be employed to implement a memory, for example, static randomaccess memory (SRAM), synchronous dynamic RAM (SDRAM), nonvolatile / Flash-type memory, or any other type of memory capable of storing information.

[0086] In examples, a memory may be used to store logic instructions including, without limitation, one or more software modules and / or other sufficient information for operation, safety procedures, and / or routine maintenance processes. In examples, logic instructions may be employed to operate, control, and / or monitor the operation of the system and / or one or more subcomponents thereof. In examples, the memory may store an operating system and one or more software applications, instructions, programs, and / or data to implement the methods described herein and the functions attributed to the various systems. Any operation of the described system may be implemented in hardware, software, or a combination thereof. In the context of software, operations represent computer-executableinstructions stored on one or more computer-readable storage media that, when executed by one or more processors, perform the recited operations. Computer-executable instructions may include programs, objects, routines, data structures, components, and the like that perform one or more functions or implement particular abstract data types.

[0087] It will be apparent to those skilled in the art that various modifications and variation can be made w ithout departing from the spirit or scope of the disclosure. Thus, it is intended that the present application covers the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A process for recovery of polymer grade propylene from liquified petroleum gas (LPG) comprising: feeding and LPG stream to a pre-fractionating section of a dividing wall column; and producing by the dividing wall column a polymer grade propylene product stream and a propane product stream, wherein, the polymer grade propylene product stream is obtained as an overhead stream or as a side draw stream.

2. The process of claim 1, further comprising producing a light ends stream and a C4+ containing stream.

3. The process of claim 2, wherein: the light ends stream is produced as an overhead stream, the polymer grade propylene product stream is produced is a first side draw stream, the propane product stream is produced as a second side draw stream, and the C4+ containing stream is produced as a bottoms product stream.

4. The process of claim 3. wherein the first side draw stream is drawn below the overhead stream, and the second side draw stream is drawn below the first side draw stream.

5. The process of claim 4, wherein the second side draw stream is drawn from a main fractionation section of the dividing wall column.

6. The process of claim 2, w herein: the light ends stream is produced as a first overhead stream, the polymer grade propylene product stream is produced is a second overhead stream, the propane product stream is produced as a side draw7stream, and the C4+ containing stream is produced as a bottoms product stream.

7. The process of claim 6, wherein the draw stream is drawn from a main fractionation section of the dividing w all column.

8. The process of claim 3 or 6, further comprising passing at least a portion of the bottoms product stream to reboiler and extracting the remaining portion.

9. The process of claim 1, further comprising directing the polymer grade propylene product stream to a first storage unit and directing the propane product stream to a second storage unit.

10. A dividing wall column for production of polymer grade propylene from Liquified Petroleum Gas (LPG) comprising: one or more dividing walls in the dividing wall column and configured to define a pre-fractionating section and a main fractionation section inside the dividing wall column; an LPG feed configured to input LPG feed at the pre-fractionating section:one or more overhead streams; one or more side draw streams comprising a propane product side draw stream drawn from the main fractionationsection of the dividing wall column; a bottoms product stream; and a reboiler system configured to heat and recycle to the dividing wall column at least a portion of the bottoms product stream.

11. The dividing wall column of claim 10, wherein the one or more dividing walls comprise two dividing walls located at different heights within the dividing wall column.

12. The dividing wall column of claims 10 or 11, wherein at least one of the one or more dividing walls extends down from a top end of the dividing wall column.

13. The dividing wall column of claim 10, wherein one dividing wall at least partially overlaps with another dividing wall.

14. The dividing wall column of claim 10, wherein the one or more overhead streams comprises an overhead stream of light ends.

15. The dividing wall column of claim 10 or 14. wherein the one or more side draw streams further comprises a propylene grade polymer product stream drawn below the one or more overhead streams.

16. The dividing wall column of claim 10, wherein the one or more overhead streams comprises a first overhead stream and a second overhead stream, wherein one of the first overhead stream or the second overhead stream comprises a propylene grade polymer product stream.

17. The dividing wall column of claim 10, further comprising a condenser system for each overhead stream of the one or more overhead streams.

18. The dividing wall column of claim 17, further comprising an overhead recycle line for each of the one or more overhead streams, each overhead recycle line configured to recycle at least a portion of the respective overhead stream.

19. A scheme for producing polymer grade propylene from Liquified Petroleum Gas (LPG) comprising: a single distillation column, wherein the single distillation column is a dividing wall column comprising: one or more dividing walls in the dividing wall column and configured to define a pre-fractionating section and a main fractionation section inside the dividing wall column; an LPG feed configured to input LPG feed at the pre-fractionating section; one or more overhead streams; one or more side draw streams comprising a propane product side draw stream drawn from the main fractionation section of the dividing wall column; and a bottoms product stream.

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