Abstract:
An energy efficient, high throughput process for aromatics recovery can be readily implemented by revamping existing sulfolane solvent extraction facilities, or constructing new ones, so as to incorporate unique process operations involving liquid-liquid extraction and extractive distillation. Current industrial sulfolane solvent based liquid-liquid extraction processes employ a liquid-liquid extraction column, an extractive stripping column, a solvent recovery column, a raffinate wash column, and a solvent regenerator. The improved process for aromatic hydrocarbon recovery from a mixture of aromatic and non-aromatic hydrocarbons requires transformation of the extractive stripping column into a modified extractive distillation column. The revamping incorporates the unique advantages of liquid-liquid extraction and extractive distillation into one process to significantly reduce energy consumption and increase process throughput. The revamp entails essentially only piping changes and minor equipment adjustments of the original liquid-liquid extraction facility, and is therefore, reversible.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional patent application No. 61/123,800 which was filed on Apr. 10, 2008. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to energy efficient processes for aromatics recovery that require significantly less energy but achieve substantially higher throughput relative to current sulfolane solvent based liquid-liquid extraction techniques. The improved process that can be readily implemented by revamping existing sulfolane solvent extraction facilities, or constructing a new one, so as to incorporate unique process operations involving liquid-liquid extraction and extractive distillation. 
     BACKGROUND OF THE INVENTION 
     Liquid-liquid extraction (LLE) using sulfolane with water as the extractive solvent is the most important commercial process for purifying the full-range (C 6 -C 8 ) of aromatic hydrocarbons from petroleum streams, including reformate, pyrolysis gasoline, coke oven oil, and coal tar. U.S. Pat. No. 3,179,708 to Penisten describes an early sulfolane solvent based LLE process that employed an LLE column, a raffinate water washing column (WWC), and a solvent recovery column (SRC). A hydrocarbon feed mixture is contacted in the LLE column with an aqueous sulfolane solvent, which selectively dissolves the aromatic components from the hydrocarbon feedstock, to form a raffinate phase comprising one or more non-aromatic hydrocarbons and an extract phase comprising the solvent and at least one dissolved aromatic compound. The extract phase is transferred to the SRC where the aromatic hydrocarbons are steam stripped from the sulfolane solvent, thereby recovering the components of greatest volatility from the overhead and the purified aromatic product from the side-cut of the SRC. The overhead light components which include aromatics are recycled as a part of the reflux to the LLE column. Finally, water condensate collected from the SRC overhead and side-cut are combined and recycled to the WWC where sulfolane is removed from the raffinate phase to produce a solvent free non-aromatic product. 
     U.S. Pat. No. 4,046,675 to Asselin disclose a crucial improvement to the earlier LLE processes by incorporating an extractive stripping column (ESC) to remove non-aromatic contaminants from the extract phase of the LLE column before entering the SRC. Non-aromatic components and a significant portion of aromatic components in the LLE extract phase are removed from the ESC overhead and recycled as a liquid reflux to the LLE column. Rich solvent, which contains aromatic components and is virtually free from non-aromatic components, is withdrawn from the bottom of the ESC and fed to the SRC. To enhance ESC operations, an aromatic-containing rich solvent is withdrawn from the SRC side-cut and introduced into the ESC with the LLE extract phase. 
     The addition of the ESC has been critical to the success of the current LLE process for recovering the full range (C 6 -C 8 ) aromatic hydrocarbons using aqueous sulfolane as the extractive solvent. However, a major drawback of this process is the high energy (steam) consumption of the ESC, in which all the overhead condensate is recycled to the lower portion of the LLE column as the reflux. In order to maintain the purity of the aromatic product, a substantial amount of energy is needed by the reboiler to vaporize and remove nearly all non-aromatic hydrocarbons from the bottom of the ESC. As a result of this requirement, the overhead vapor from the ESC can contain as much as 25-30% benzene and nearly 10% heavier aromatics, which are condensed and recycled to the bottom of LLE column as the reflux. Consequently, the recycled benzene and heavier aromatics are extracted by the solvent again in the LLE column and fed back to the ESC. Another significant drawback of current ESC operations is that light non-aromatic hydrocarbons (C 5 -C 6 ), due their higher affinities with the solvent, are continuously accumulated in a closed loop between the top of ESC and the bottom of the LLE column with no way out but consuming a significant amount of vaporization energy. Therefore, this stream has to be purged from time to time in order to keep the process in continuous operation. This large reflux operation not only requires high energy but also creates a bottleneck at the ESC and reduces throughput of the LLE process. 
     U.S. Pat. No. 5,336,840 to Forte notes that in 1986, the energy costs (comprising steam, electric power and cooling water) for a typical 10,000 barrel per day (or 420,000 metric ton per year) sulfolane solvent based LLE process, amounted to as high as 83%, with solvent make-up charges, labor and maintenance costs making up for the remaining 17% of the total processing costs. In light of the recent drastic increases in oil and natural gas prices, energy costs associated with this process today are significantly higher, thus any reduction in processing energy would be very beneficial. 
     Various schemes have been proposed and developed with the goal of generating energy savings in the basic process of continuous liquid-liquid extraction for aromatic hydrocarbon recovery and steam stripping for solvent recovery. Most of these schemes which are based on heat integration, such as by using heat exchangers between process streams, pressure reduction devices between process vessels, and the like, have achieved only limited success but with significant increase in equipment costs. 
     SUMMARY OF THE INVENTION 
     The present invention is based in part on the discovery that substantial energy savings and enhanced throughput can be realized by making relatively simple changes to existing conventional sulfolane solvent based liquid-liquid extraction (LLE) processes. The revamping of existing facilities requires minimal capital expenditure and downtime as the conversion requires only piping changes and minor equipment adjustments. 
     In a typical sulfolane solvent based extractive distillation (ED) process for aromatics recovery, solvent is added to an upper portion of the extractive distillation column (EDC) and feed containing aromatic hydrocarbons is introduced to a middle portion of the EDC. As the nonvolatile sulfolane solvent descends through the column, it preferentially extracts the aromatic components to form a rich solvent which moves toward the bottom of the EDC while the non-aromatic component vapor ascends to the top. The overhead vapor is condensed and a portion of the condensate is recycled to the top of the EDC as reflux, while the other portion is withdrawn as the raffinate product. Rich solvent containing solvent and aromatic components is fed to a solvent recovery column (SRC) where the aromatic components are recovered as an overhead product and lean solvent, that is free of the feed components, is recovered as the bottom product, which is recycled to the upper portion of the EDC. A portion of the overhead product is recycled to the top of the SRC as reflux to knock down any entrained solvent in the overhead vapor. The SRC is optionally operated under reduced pressure (vacuum) or with a stripping medium or both to lower the column bottom temperature. Water condensate collected from overheads of both the EDC and the SRC are recycled for generating stripping steam for the SRC. Conventional sulfolane solvent based ED processes are further disclosed in U.S. Pat. No. 3,551,327 to Kelly et al. and U.S. Pat. No. 4,053,369 to Cines, which are incorporated herein by reference. 
     Sulfolane solvent based ED processes are simpler and consume less energy than LLE processes for aromatic hydrocarbon recovery, however, application of the ED process is constrained by the boiling range of the feedstock. In order to achieve acceptable levels of aromatic purity and recovery, the solvent must essentially keep all the benzene, which is the lightest aromatic compound with a boiling point of 80.1° C., in the EDC bottom. This condition drives virtually all the heaviest non-aromatics into the overhead of the EDC. It would be desirable to position an LLE column in front of the EDC where heavy non-aromatics are preferentially rejected by the extract phase due to their lower polarity so that only aromatics and the lightest non-aromatics are extracted into the extract phase. By feeding this extract phase into an EDC, essentially all the lightest non-aromatics can be distilled into the overhead of the EDC and all the aromatics are recovered in the EDC bottom rich solvent stream, which is then fed to the SRC to recover high purity aromatic products. 
     Current industrial sulfolane solvent based LLE processes for aromatic hydrocarbon recovery typically employ a liquid-liquid extraction (LLE) column, an extractive stripping column (ESC), a solvent recovery column (SRC), a raffinate water wash column (WWC), and a solvent regenerator (SRG). In implementing the inventive revamping process, one feature is to convert the existing ESC into a modified extractive distillation column (EDC) by merely implementing piping changes to the existing ESC. This simple piping modification, in effect, incorporates the advantages of both the LLE and ED into one process to generate substantial energy savings as well as achieve significant throughput increase for an existing liquid-liquid extraction process for aromatic hydrocarbon recovery. Another feature of the present invention is the elimination of the energy consuming and troublesome LLE reflux, so that the LLE column in the new configuration is operated without a reflux. 
     In a preferred embodiment, the LLE column is operated under conditions such as to reject all C 8   +  non-aromatics and most of the C 7  non-aromatics and to allow only C 5 -C 6  non-aromatics and small amounts of C 7  non-aromatics to be extracted along with the aromatics into the extract phase. This expected phenomenon is based on the realization that heavier non-aromatics have relatively lower polarity and less affinity with the extractive solvent, and are, therefore, easier to be rejected by the solvent in an LLE column. In operation of the inventive process, the extract phase, which contains the solvent, all the (C 6 -C 8 +) aromatics, only C 5 -C 6  non-aromatics, and minor amounts of C 7  non-aromatics, is withdrawn from the bottom of the LLE column and transferred to the middle portion of the modified EDC (formerly ESC) as the hydrocarbon feed. 
     By modified EDC is meant that only a portion of the required lean solvent is introduced to an upper portion of the EDC, while the other portion of the solvent is already in the hydrocarbon feed to the EDC (the solvent-rich extract stream from the LLE column). In a typical (that is, non-modified) EDC, all of the required lean solvent is introduced through the upper portion of the column and the hydrocarbon feed which enters through the middle of the column is solvent free. The function of the modified EDC of the present invention is quite different from that of the ESC. The ESC has only a stripping section since the feed (the solvent-rich aromatic extract phase from the LLE column) is introduced through the top of the column. The ESC strips substantially all of the non-aromatic hydrocarbons for removal through the column overhead so that only aromatic hydrocarbons are in the solvent-rich stream that exits the bottom of the column. For the modified EDC, the same feed is introduced into a middle portion of the column while a portion of the required hydrocarbon-free lean solvent is fed through the upper portion of the column. In this configuration, the modified EDC has both a stripping section, which is below the feed tray, and a rectifying section, which is above the feed tray, to respectively purify both the solvent-rich stream in the column bottom and the non-aromatic raffinate stream in the column overhead. 
     In order to achieve satisfactory aromatic purity and recovery in the modified EDC, the solvent needs to keep essentially all benzene (the lightest aromatic) in the EDC bottom and virtually all of the heaviest non-aromatics is driven into the overhead of the EDC. In the inventive process, operation of the modified EDC is quite easy since essentially all of the heavy non-aromatics are removed from the EDC feed by the front-end LLE column, thus allowing only C 5 -C 6  non-aromatics with minor amounts of C 7  non-aromatics to be present in the feed to the EDC. This is crucial because the existing ESC normally has only 40 to 45 separating trays (or roughly 16 to 18 theoretical trays), which is adequate for the EDC operation when only light non-aromatics is present in the hydrocarbon feedstock. In the absence of heavy non-aromatics and greatly reduced total non-aromatics in the feed, the energy requirement of the modified EDC is substantially reduced as compared to the original ESC. 
     Since non-aromatics have very limited solubility in the solvent, such as sulfolane, they tend to generate undesirable two liquid phases in the upper portion of the modified EDC. A further feature of the inventive process is to reduce the two liquid phase region in the upper portion of the modified EDC to thereby enhance column performance and operation. This is achieved by greatly reducing the level of non-aromatics in the EDC feed. 
     Another important feature of the invention is the elimination of the reflux to the top of the modified EDC to further: (1) reduce energy consumption of the column; (2) reduce vapor loading of the upper portion of the column, thereby, increasing the column throughput; and (3) reduce the two liquid phase region in the upper portion of the column, since the reflux contains essentially pure non-aromatics. In an ordinary distillation column, the overhead liquid reflux is essential for generating the necessary liquid phase in the rectifying section of the column which contacts the uprising vapor phase from tray-to-tray for separating the key components in the feed mixture. Depending upon the particular application, normal reflux-to-distillate ratio of an ordinary distillation column is approximately 1 to 20. In the modified EDC, however, the liquid phase in the rectifying section is the nonvolatile, polar solvent, which preferentially absorbs the more polar components (the aromatics) from the uprising vapor phase. This allows the less polar components (the non-aromatics) vapor to ascend to the top of the EDC. It has been demonstrated in a three-meter diameter EDC for benzene, toluene, and xylene (BTX) aromatics recovery that adding reflux to the EDC has no effect in enhancing the separation. In other words, adding reflux to the modified EDC has no effect on the purity and recovery of the overhead product (the non-aromatic raffinate). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic flow process of a prior art liquid-liquid extraction process for aromatics recovery; 
         FIG. 2  is a schematic flow process a revamped liquid-liquid extraction process (I) for aromatics recovery; and 
         FIG. 3  is a schematic flow process of another revamped liquid-liquid extraction process (II) for aromatics recovery. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     I. Description of the Conventional LLE Process 
     Referring to  FIG. 1 , hydrocarbon feed containing aromatic and non-aromatics is fed via line  1  to the middle portion of LLE column  200 , while lean solvent is introduced near the top of LLE column  200  via line  2  to counter-currently contact the hydrocarbon feed. The aromatic hydrocarbons in the feed typically comprise benzene, toluene, ethylbenzene, xylenes, C 9   +  aromatics, and mixtures thereof and the non-aromatic hydrocarbons comprise C 5  to C 9   +  paraffins, naphthenes, olefins, and mixtures thereof. Suitable extractive solvents include, for example, sulfolane, sulfolane with water as co-solvent, tetraethylene glycol (TTEG), TTEG with water as co-solvent, sulfolane and TTEG mixtures, sulfolane and TTEG mixtures with water as co-solvent, triethylene glycol (TEG), TEG with water as co-solvent, sulfolane and TEG mixtures, sulfolane and TEG mixtures with water as co-solvent, and the combinations thereof. A preferred solvent comprises sulfolane with water as the co-solvent. Raffinate phase containing essentially the non-aromatics with a minor amount of solvent is withdrawn from the top of LLE column  200  and fed to a lower portion of water washing column (WWC)  208  via line  3 . The extract phase is transferred from the bottom of LLE column  200  via line  4  and is mixed with a secondary lean solvent from line  27  or a rich solvent from the side-cut of solvent recovery column (SRC)  214  from line  28 ; the combined stream is fed to the top of extractive stripping column (ESC)  204  through line  29 . 
     The vapor flow in ESC  204  is generated by reboiler  206 , which is normally heated by steam at a rate that is sufficient to control the column bottom temperature and the overhead stream composition and flow rate. Overhead vapor exiting the top of ESC  204  is condensed in a cooler (not shown) and transferred via line  5  to an overhead receiver  202 , which serves to effect a phase separation between the hydrocarbon and the water phases. The hydrocarbon phase, containing the non-aromatics and up to 30-40% benzene and heavier aromatics, is recycled to the lower portion of LLE column  200  as reflux via line  6 . The water phase is transferred via lines  9  and  12  to steam generator  212  to generate stripping steam for SRC  214 . Rich solvent consists of pure aromatics and the solvent is withdrawn from the bottom of ESC  204  and transferred to the middle portion of SRC  214  via lines  7  and  25 . In order to minimize the bottom temperature of SRC  214 , receiver  216  is connected to a vacuum source to generate sub-atmospheric condition in SRC  214 . Stripping steam is injected from steam generator  212  via line  17  into the lower portion of SRC  214  to assist in the removal of aromatic hydrocarbons from the solvent. An aromatic concentrate, containing water and being substantially free of solvent and non-aromatic hydrocarbons, is withdrawn as an overhead vapor stream from SRC  214  and introduced into an overhead receiver  216  via line  20  after being condensed in a cooler (not shown). 
     Overhead receiver  216  serves to effect a phase separation between the aromatic hydrocarbon and the water phases. A portion of the aromatic hydrocarbon phase is recycled to the top of SRC  214  as reflux via line  22 , while the remainder portion is withdrawn as aromatic hydrocarbon product through line  23 . Water phase accumulated in the water leg of overhead receiver  216  is fed via line  24  to an upper portion of WWC  208  as wash water at a location below the interface between the hydrocarbon phase and the water phase near the top of WWC  208 . The solvent is removed from the LLE raffinate through a counter-current water wash and the solvent-free non-aromatics, which accumulate in the hydrocarbon phase, are then withdrawn from the top of WWC  208  as solvent-free non-aromatic products through line  11 . A water phase, containing the solvent, exits through the bottom of WWC  208  and is fed to steam generator  212  via lines  10  and  12  where it is transformed into stripping steam that is then introduced into SRC  214  via line  17 . 
     A split stream of the lean solvent is diverted and introduced into SRG  210  via line  13  and steam is introduced into SRG  210  through line  16 , at a location below the lean solvent feed entry point. Deteriorated solvent and polymeric sludge are removed as a bottom stream through line  15 , while the regenerated solvent and substantially all the stripping steam, are recovered as an overhead stream that is introduced into the lower portion of SRC  214  via line  14  as a part of the stripping steam. 
     II. Description of the Revamped LLE Process (I) for Aromatics Recovery 
       FIG. 2  illustrates an energy efficient revamped process that is derived by making a few simple modifications to the process shown in  FIG. 1 . In particular, lines  4 ,  6 ,  27  and  28  are eliminated from the scheme shown in  FIG. 1  whereas lines  44 ,  46 ,  68 , and  69  are incorporated. As shown in  FIG. 2 , LLE column  300  is operated without a liquid reflux as the hydrocarbon feed containing aromatics and non-aromatics is fed to a location near the bottom of LLE column  300  via line  41 . The lean solvent is introduced at near the top of LLE column  300  through line  42  to counter-currently contact the hydrocarbon feed. Suitable extractive solvents include, for example, sulfolane, sulfolane with water as co-solvent, tetraethylene glycol (TTEG), TTEG with water as co-solvent, sulfolane and TTEG mixtures, sulfolane and TTEG mixtures with water as co-solvent, triethylene glycol (TEG), and TEG with water as co-solvent, sulfolane and TEG mixtures, sulfolane and TEG mixtures with water as co-solvent, and the combinations thereof. Preferred solvents include sulfolane with water as the co-solvent, and TTEG with water as the co-solvent. Operating conditions of LLE column  300  are adjusted to yield a raffinate phase containing non-aromatics with essentially no aromatic impurities and a minor amount of solvent, and an extract phase containing the solvent, essentially all the aromatics in the hydrocarbon feed, and the C 5 -C 6  non-aromatics with only minor amounts of C 7  non-aromatics. 
     The extract phase is transferred from the bottom of LLE column  300  and is fed to the middle portion of a modified extractive distillation column (EDC)  304  through line  44 . EDC  304  is a modified EDC because only a portion of the required lean solvent is introduced to the upper portion of the EDC while the other portion of the solvent is already in the hydrocarbon feed to the EDC (the extract stream from the LLE column  300 ). In contract, in a typical EDC all the required lean solvent is introduced to the upper portion of the column and the hydrocarbon feed that is fed to the middle portion of the column is solvent free. Modified EDC  304  can employ the same ESC  204  unit as shown in  FIG. 1  but accommodating the different stream arrangements. To enhance the performance of modified EDC  304 , the original trays in ESC  204  may be replaced with the newer high capacity trays to better handle the two liquid phase phenomena in the upper portions of modified EDC  304 . 
     A raffinate phase is withdrawn from the top of LLE column  300  via line  43 . A separate stream of lean solvent is fed to the upper portion of modified EDC  304 , preferably at the top tray of modified EDC  304  through line  68 . Vapor flow in modified EDC  304  is generated by reboiler  306 , which is normally heated by steam at a rate that is sufficient to control the column bottom temperature and the overhead stream composition and flow rate. Overhead vapor exiting the top of modified EDC  304  is condensed in a cooler (not shown) and then transferred via line  45  to overhead receiver  302 , which serves to effect a phase separation between the hydrocarbon phase and the water phase. The hydrocarbon phase, which contains the non-aromatics with minor amounts of benzene (preferably less than 2 wt %) and traces of entrained solvent, is withdrawn from overhead receiver  302  via line  46  and is mixed with the raffinate stream from LLE column  300 . The combined stream is fed to the lower portion of WWC  308  through line  47 . No hydrocarbon phase from overhead receiver  302  is recycled as reflux to modified EDC  304  or LLE column  300 . The water phase from overhead receiver  302  is transferred via lines  50  and  53  to steam generator  312  where it is transformed into stripping steam for SRC  314 . Rich solvent consists of pure aromatics and the solvent is withdrawn from the bottom of modified EDC  304  and is transferred to the middle portion of SRC  314  via lines  48  and  66 . 
     Operation of SRC  314 , WWC  308 , and SRG  310  are essentially unchanged from those of corresponding SRC  214 , WWC  208  and SRG  210  in the conventional LLE process as depicted in  FIG. 1 , although operational adjustments may be needed to take full advantage of the revamped process with its attendant lower energy requirements and higher throughput. Typically, the weight ratio of polar solvent that is introduced into the modified EDC to that which is introduced into the LLE column ranges from 0.1 to 10 and preferably the ratio ranges from 0.5 to 1.5. The extraction temperature and pressure of the LLE column are typically maintained at between 20 to 100° C. and between 1.0 to 6.0 Bar, respectively, and preferably are maintained at between 50 to 90° C. and between 4.0 to 6.0 Bar, respectively. The reboiler temperature and pressure of the modified EDC are typically maintained at between 120 to 180° C. and between 1.0 to 2.0 Bar, respectively, and preferably between 130 to 150° C. and between 1.0 to 1.5 Bar, respectively. 
     In preferred embodiments, the LLE column is operated without a liquid reflux near the bottom of the column and/or the modified EDC is operated without liquid reflux near the top of the column. Finally, the modified EDC is preferably operated under conditions as to maximize benzene recovery in the solvent-rich aromatic concentrate stream, whereby substantially all non-aromatic hydrocarbons are driven into the overhead of the modified EDC. 
     Optionally, a portion of the non-aromatic raffinate stream  43  from LLE column  300  can be recycled via line  69  into hydrocarbon feed stream  41  to LLE column  300 . When the non-aromatic reflux from the top of modified EDC  304  to the bottom of LLE column  300  is eliminated, recycling ensures a phase separation between the solvent-rich aromatic extract phase and the non-aromatic raffinate phase when the hydrocarbon feed to the LLE column has a high aromatic content (&gt;70%), such as in the case of pyrolysis gasoline, which is a common feed for aromatic recovery. 
     III. Description of the Revamped LLE Process (II) for Aromatics Recovery 
     The revamped LLE process (I) shown in  FIG. 2  can be is further simplified by eliminating the solvent regenerator SRG  310 . In the revamped LLE process (II) as illustrated in  FIG. 3 , WWC  408  functioned not only as the raffinate water wash column but also as the lean solvent regenerator. The lean solvent is withdrawn from the bottom of SRC  414  via lines  96  and  104  and is fed to both LLE column  400  and modified EDC  404  through lines  82  and  105 , respectively. 
     As shown in  FIG. 3 , LLE column  400  is operated without a liquid reflux as the hydrocarbon feed containing aromatics and non-aromatics is fed to a location near the bottom of LLE column  400  via line  81 . Lean solvent is introduced at near the top of LLE column  400  through line  82  to counter-currently contact the hydrocarbon feed. Operating conditions of LLE column  400  are adjusted to yield a raffinate phase containing non-aromatics with essentially no aromatic impurities and a minor amount of solvent, and an extract phase containing the solvent, essentially all the aromatics in the hydrocarbon feed, and the C 5 -C 6  non-aromatics with only minor amounts of C 7  non-aromatics. 
     The extract phase is transferred from the bottom of LLE column  400  and is fed to the middle portion of a modified extractive distillation column (EDC)  404  through line  84 . A raffinate phase is withdrawn from the top of LLE column  400  via line  83 . A separate stream of lean solvent is fed to the upper portion of modified EDC  404 , preferably at the top tray of modified EDC  404  through line  105 . Vapor flow in modified EDC  404  is generated by reboiler  406 , which is normally heated by steam at a rate that is sufficient to control the column bottom temperature and the overhead stream composition and flow rate. Overhead vapor exiting the top of modified EDC  404  is condensed in a cooler (not shown) and then transferred via line  85  to overhead receiver  402 , which serves to effect a phase separation between the hydrocarbon phase and the water phase. The hydrocarbon phase, which contains the non-aromatics with minor amounts of benzene (preferably less than 2 wt %) and traces of entrained solvent, is withdrawn from overhead receiver  402  via line  86  and is mixed with the raffinate stream from LLE column  400 . The combined stream is fed to the lower portion of WWC  408  through line  87 . No hydrocarbon phase from overhead receiver  402  is recycled as reflux to modified EDC  404  or LLE column  400 . The water phase from overhead receiver  402  is transferred via lines  90  and  93  to steam generator  412  where it is transformed into stripping steam for SRC  414 . Rich solvent consists of pure aromatics and the solvent is withdrawn from the bottom of modified EDC  404  and is transferred to the middle portion of SRC  414  via lines  88  and  103 . 
     A slip stream of the lean solvent is transferred from line  104  to cooler  422  (newly added equipment) via line  94  and is then fed to the lower portion of WWC  408  at a location that is below the raffinate feed entry point which is connected to line  87 . In this fashion, the solvent stays in the water phase in the lower portion of WWC  408  due to its higher density (relative to water). Residual (heavy) hydrocarbons are removed from the lean solvent through the counter-current water wash and accumulate in the hydrocarbon phase along with the non-aromatic raffinate from LLE column  400  and modified EDC  404 . The hydrocarbon phase is then withdrawn from the top of WWC  408  as solvent-free non-aromatic products through line  92 . Water phase exiting the bottom of WWC  408 , which contains the solvent, is passed through a magnetic filter,  420  (a newly added equipment) via line  91  to remove any tramp iron, polymeric sludge, and/or any other highly polar matters. The filtered water stream with minor amounts of solvent is then transferred to steam generator  412  via line  93  where it is transformed into stripping steam to be introduced into SRC  414  via line  95 . 
     Operating conditions in this revamp process are similarly to those for the process shown in  FIG. 2 . In addition, optionally, a portion of the non-aromatic raffinate stream  83  from LLE column  400  can be recycled via line  106  into hydrocarbon feed stream  81  to LLE column  400 . 
     EXAMPLES OF PREFERRED EMBODIMENTS 
     The following examples are presented to further illustrate different aspects and embodiments of the invention and are not to be considered as limiting the scope of the invention. Data in Examples 1 and 2 were derived by computer simulation model which was upgraded for improved accuracy via actual commercial process data. 
     Example 1 
     Comparative 
     Base Case 
     Referring to  FIG. 1 , one thousand (1,000) Kg/Hr of the hydrocarbon feed at 75° C. and 6.4 Bar (pressure) are fed continuously to the middle portion of LLE column  200  via line  1 . This stream contains approximately 25 wt % benzene, 19 wt % toluene, 17 wt % C 8  aromatics, 0.5 wt % C 9   +  aromatics, and 39 wt % C 5 -C 9   +  non-aromatics. Thirty six hundred (3,600) Kg/Hr of the sulfolane solvent containing 0.8 wt % water at 81° C. and 6.4 Bar are introduced to the upper portion of LLE column  200  via line  2  entering the column at a location below the interface between the raffinate phase and extract phase. Multi-stage counter-current liquid-liquid extraction occurs in LLE column  200  at a temperature of 80° C. and a pressure of 6.4 Bar. The raffinate stream, with only 0.27 wt % C 8   +  aromatics and essentially free of benzene and toluene, is withdrawn from the top of the LLE column and transferred to the lower portion of the WWC via line  3  at a flow rate of 397 Kg/Hr. The extract stream, containing 78 wt % sulfolane, 0.6 wt % water, essentially all the aromatics in the LLE hydrocarbon feed, and only 0.31 wt % C 7   +  non-aromatics, is transferred from the bottom of the LLE column via line  4 , and is mixed with 350 Kg/Hr of the sulfolane solvent (with 0.8 wt % water) from line  27 . The mixed stream is fed to the top of ESC  204  through line  29  at a rate of 4,934 Kg/Hr. 
     Approximately 249,000 Kcal/Hr of the thermal energy, provided by the medium pressure steam to reboiler  206 , are required to generate the vapor stream in ESC  204 , and to strip essentially all the non-aromatics from the ESC bottom in order to yield the aromatic products with acceptable purity. The ESC bottom temperature is quite high at 173° C. The overhead vapor exits ESC  204  via line  5  and is transferred to overhead accumulator  202  after being condensed by a cooler. The hydrocarbon phase from overhead accumulator  202 , containing roughly 25 wt % benzene and 10 wt % C 7   +  aromatics, is recycled to bottom of LLE column  200  as the reflux at a flow rate of 380 Kg/Hr via line  6 . The recycle stream requires frequent purge to release accumulated C 5 -C 6  non-aromatics. Rich solvent from the bottom of ESC  204 , consisting of 86 wt % sulfolane, 0.3 wt % water, and substantially pure C 6 -C 9   +  aromatics, is fed to SRC  214  through lines  7  and  25  at flow rate of 4,534 Kg/Hr, temperature of 173° C. and pressure of 2.3 Bar. 
     WWC  208  is operated at a temperature of 60-80° C. and a pressure of 1.5 Bar. Water from SRC  214  overhead accumulator  216  is fed to upper portion of WWC  208  to counter-currently extract the sulfolane from the LLE raffinate, at a water-to-raffinate weight ratio of 0.25. Solvent-free raffinate products are removed from the top of WWC  208  at a rate of 388 Kg/Hr through line  11 . 
     The process stream data for LLE column  200 , ESC  204 , and WWC  208 , including the stream composition, flow rate, temperature and pressure are summarized in Table 1. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Composition of the Original Liquid-Liquid 
               
               
                 Extraction Process Streams (wt %) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                 1 
                 2 
                 3 
                 4 
                 29 
               
               
                   
               
               
                 C 5  Paraffins 
                 0.50 
                 0.00 
                 1.26 
                 0.05 
                 0.05 
               
               
                 C 5  Naphthenes 
                 1.10 
                 0.00 
                 2.78 
                 2.55 
                 2.37 
               
               
                 C 5  Isoparaffins 
                 0.40 
                 0.00 
                 1.01 
                 0.06 
                 0.05 
               
               
                 C 6  Paraffins 
                 4.91 
                 0.00 
                 12.38 
                 0.14 
                 0.13 
               
               
                 C 6  Naphthenes 
                 6.11 
                 0.00 
                 15.41 
                 2.00 
                 1.86 
               
               
                 C 6  Isoparaffins 
                 6.41 
                 0.00 
                 16.17 
                 0.31 
                 0.29 
               
               
                 Benzene 
                 25.25 
                 0.00 
                 0.00 
                 7.64 
                 7.10 
               
               
                 C 7  Paraffins 
                 2.51 
                 0.00 
                 6.32 
                 0.02 
                 0.01 
               
               
                 C 7  Naphthenes 
                 2.61 
                 0.00 
                 6.57 
                 0.14 
                 0.13 
               
               
                 C 7  Isoparaffins 
                 10.82 
                 0.00 
                 27.29 
                 0.16 
                 0.15 
               
               
                 Toluene 
                 18.94 
                 0.00 
                 0.02 
                 4.68 
                 4.35 
               
               
                 C 8  Paraffins 
                 0.70 
                 0.00 
                 1.77 
                 0.00 
                 0.00 
               
               
                 C 8  Naphthenes 
                 1.30 
                 0.00 
                 3.28 
                 0.00 
                 0.00 
               
               
                 C 8  Isoparaffins 
                 1.20 
                 0.00 
                 3.03 
                 0.00 
                 0.00 
               
               
                 C 8  Aromatics 
                 16.63 
                 0.00 
                 0.23 
                 3.79 
                 3.52 
               
               
                 C 9   +  Paraffins 
                 0.10 
                 0.00 
                 0.24 
                 0.00 
                 0.00 
               
               
                 C 9   +  Aromatics 
                 0.50 
                 0.00 
                 0.04 
                 0.11 
                 0.10 
               
               
                 Sulfolane 
                 0.00 
                 99.20 
                 2.17 
                 77.72 
                 79.25 
               
               
                 Water 
                 0.00 
                 0.80 
                 0.02 
                 0.63 
                 0.64 
               
               
                 Flow Rate (Kg/Hr) 
                 1000 
                 3600 
                 397 
                 4584 
                 4934 
               
               
                 Temperature (° C.) 
                 75 
                 81 
                 80 
                 61 
                 62 
               
               
                 Pressure (Bar) 
                 6.4 
                 6.4 
                 5.8 
                 5.8 
                 2.0 
               
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                 5 
                 6 
                 7 
                 9 
                 10 
               
               
                   
               
               
                 C 5  Paraffins 
                 0.56 
                 0.59 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 5  Naphthenes 
                 29.19 
                 30.69 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 5  Isoparaffins 
                 0.65 
                 0.69 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Paraffins 
                 1.62 
                 1.71 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Naphthenes 
                 22.97 
                 24.15 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Isoparaffins 
                 3.54 
                 3.72 
                 0.00 
                 0.00 
                 0.00 
               
               
                 Benzene 
                 24.40 
                 25.65 
                 5.57 
                 0.05 
                 0.00 
               
               
                 C 7  Paraffins 
                 0.18 
                 0.19 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 7  Naphthenes 
                 1.58 
                 1.67 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 7  Isoparaffins 
                 1.81 
                 1.91 
                 0.00 
                 0.00 
                 0.00 
               
               
                 Toluene 
                 6.34 
                 6.66 
                 4.18 
                 0.00 
                 0.00 
               
               
                 C 8  Paraffins 
                 0.01 
                 0.02 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Naphthenes 
                 0.06 
                 0.06 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Isoparaffins 
                 0.02 
                 0.02 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Aromatics 
                 2.04 
                 2.15 
                 3.65 
                 0.00 
                 0.00 
               
               
                 C 9   +  Paraffins 
                 0.00 
                 0.00 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 9   +  Aromatics 
                 0.05 
                 0.05 
                 0.11 
                 0.00 
                 0.00 
               
               
                 Sulfolane 
                 0.10 
                 0.04 
                 86.23 
                 1.23 
                 7.92 
               
               
                 Water 
                 4.86 
                 0.04 
                 0.27 
                 98.70 
                 92.05 
               
               
                 Flow Rate (Kg/Hr) 
                 400 
                 380 
                 4534 
                 20 
                 108 
               
               
                 Temperature (° C.) 
                 30 
                 31 
                 173 
                 30 
                 78 
               
               
                 Pressure (Bar) 
                 6.4 
                 6.4 
                 2.3 
                 1.0 
                 1.5 
               
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                   
                 11 
                 24 
                 27 
               
               
                   
                   
               
               
                   
                 C 5  Paraffins 
                 1.29 
                 0.00 
                 0.00 
               
               
                   
                 C 5  Naphthenes 
                 2.84 
                 0.00 
                 0.00 
               
               
                   
                 C 5  Isoparaffins 
                 1.03 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Paraffins 
                 12.65 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Naphthenes 
                 15.75 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Isoparaffins 
                 16.53 
                 0.00 
                 0.00 
               
               
                   
                 Benzene 
                 0.00 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Paraffins 
                 6.46 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Naphthenes 
                 6.71 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Isoparaffins 
                 27.89 
                 0.00 
                 0.00 
               
               
                   
                 Toluene 
                 0.02 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Paraffins 
                 1.81 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Naphthenes 
                 3.35 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Isoparaffins 
                 3.10 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Aromatics 
                 0.24 
                 0.00 
                 0.00 
               
               
                   
                 C 9   +  Paraffins 
                 0.24 
                 0.00 
                 0.00 
               
               
                   
                 C 9   +  Aromatics 
                 0.04 
                 0.00 
                 0.00 
               
               
                   
                 Sulfolane 
                 0.00 
                 0.00 
                 99.20 
               
               
                   
                 Water 
                 0.06 
                 1.00 
                 0.80 
               
               
                   
                 Flow Rate (Kg/Hr) 
                 388 
                 100 
                 350 
               
               
                   
                 Temperature (° C.) 
                 62 
                 35 
                 80 
               
               
                   
                 Pressure (Bar) 
                 1.5 
                 2.0 
                 3.0 
               
               
                   
                   
               
             
          
         
       
     
     Example 2 
     The Inventive Process 
     Revamped Case 
     This example demonstrates that the energy consumption of the ESC is substantially reduced by converting it into a modified EDC that is operated without reflux and by totally eliminating the reflux from the ESC to the LLE column. In addition to a large reduction in energy consumption, throughput of the revamped process consisting of the LLE and the modified EDC is also significantly increased. Because the revamp can be accomplished with minor piping modifications, the user has the flexibility of reverting to the original process configuration where necessary. 
     Referring to  FIG. 2 , one thousand (1,000) Kg/Hr of hydrocarbon feed at 75° C. and 6.4 Bar is fed continuously to a location near the bottom of LLE column  300  via line  41 . This stream has essentially the same composition as that of the LLE feed in example 1. Twenty one hundred (2,100) Kg/Hr of sulfolane solvent containing 0.8 wt % water at 81° C. and 6.4 Bar are introduced to the upper portion of LLE  300  via line  42 , at a location that is below the interface between the raffinate phase and the extract phase. Multi-stage counter-current liquid-liquid extraction occurs in LLE column  300  at a temperature around 80° C. and a pressure around 6.4 Bar. A non-aromatic raffinate stream, with only 0.50 wt % C 8   +  aromatics and essentially free of benzene and toluene, is withdrawn from the top of LLE column  300  and then transferred to the lower portion of WWC  308  via lines  43  and  47  after mixing with the overhead raffinate stream from modified EDC  304 . The extract stream, containing 74 wt % sulfolane, 0.6 wt % water, essentially all the aromatics in the LLE hydrocarbon feed, and less than 1.7 wt % C 7   +  non-aromatics, is transferred from the bottom of LLE column  300  and then fed to the middle portion of modified EDC  304  through  44  at a rate of 2816 Kg/Hr. 
     Twenty eight hundred (2,800) Kg/Hr of sulfolane solvent containing 0.8 wt % water from the bottom of SRC  314  are fed through lines  59 ,  67  and  68  to the upper portion, preferably to the top tray of modified EDC  304  at 80° C. and 3.0 Bar. Thermal energy, provided by the medium pressure steam to reboiler  306 , is required to generate the vapor stream in EDC  304 , and to strip essentially all the non-aromatics from modified EDC  304  bottom. However, an additional but crucial requirement of modified EDC  304  operations is to keep virtually all the benzene (the lightest aromatic) in the bottom products of modified EDC  304 . To achieve these multiple requirements, the bottom temperature of the modified EDC is maintained at only 143° C. (much lower than 173° C. for the original ESC bottom temperature), and the lean solvent flow rate to EDC  304  is kept at a level to maintain an overall solvent-to-feed weight ratio (S/F) of 6.8 (equivalent to solvent-to-feed volume ratio of 4.5). The S/F is higher than that in a typical EDC operation for aromatics recovery, because a large part of the solvent is already in the EDC hydrocarbon feed, which is the extract phase from the bottom of the LLE column. Since the solvent is essentially nonvolatile in this operation due to its high boiling point, increased solvent circulation (higher S/F) does not affect the process energy requirement significantly. 
     The overhead vapor exits modified EDC  304  via line  45  and is transferred to overhead accumulator  302  after being condensed in a cooler. The hydrocarbon phase from overhead accumulator  302 , which contains roughly 1.1 wt % benzene, insignificant heavier aromatics, 0.03 wt % entrained sulfolane and 0.03 wt % water, is mixed via line  46  with the LLE overhead raffinate stream. The mixed non-aromatic stream containing approximately 0.3 wt % benzene is transferred to WWC  308  at a rate of approximately 396 Kg/Hr via line  47 . The thermal energy required at modified EDC reboiler  306  is only 169,000 Kcal/Hr, which is substantially lower than that of ESC  204  ( FIG. 1 ) in the base case (249,000 Kcal/Hr). The energy saving is almost 32% by converting ESC  204  into modified EDC  304  without reflux. Elimination of the LLE reflux from modified EDC  304  can substantially increase throughput of the revamped LLE process by 37% ((984-716) Kg/Hr/716 Kg/Hr=37%), assuming the capacity of modified EDC  304  is limited by the vapor flow in the column, and therefore, is the bottleneck of the revamped LLE process. 
     Stream data of LLE column  300 , modified EDC  304 , and WWC  308  of the revamped process, including the stream composition, flow rate, temperature and pressure are summarized in Table 2. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Composition of the Revamped Liquid-Liquid 
               
               
                 Extraction Process Streams (wt %) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                 41 
                 42 
                 43 
                 44 
                 45 
               
               
                   
               
               
                 C 5  Paraffins 
                 0.50 
                 0.00 
                 1.19 
                 0.06 
                 1.41 
               
               
                 C 5  Naphthenes 
                 1.30 
                 0.00 
                 2.25 
                 0.23 
                 5.74 
               
               
                 C 5  Isoparaffins 
                 0.40 
                 0.00 
                 0.94 
                 0.05 
                 1.17 
               
               
                 C 6  Paraffins 
                 4.90 
                 0.00 
                 12.52 
                 0.48 
                 11.64 
               
               
                 C 6  Naphthenes 
                 6.10 
                 0.00 
                 13.44 
                 0.81 
                 19.77 
               
               
                 C 6  Isoparaffins 
                 6.40 
                 0.00 
                 15.92 
                 0.67 
                 16.30 
               
               
                 Benzene 
                 25.20 
                 0.00 
                 0.00 
                 8.95 
                 1.09 
               
               
                 C 7  Paraffins 
                 2.50 
                 0.00 
                 6.86 
                 0.20 
                 4.78 
               
               
                 C 7  Naphthenes 
                 2.60 
                 0.00 
                 6.37 
                 0.28 
                 6.71 
               
               
                 C 7  Isoparaffins 
                 10.80 
                 0.00 
                 28.58 
                 0.95 
                 23.24 
               
               
                 Toluene 
                 18.90 
                 0.00 
                 0.02 
                 6.71 
                 0.03 
               
               
                 C 8  Paraffins 
                 0.70 
                 0.00 
                 2.01 
                 0.05 
                 1.10 
               
               
                 C 8  Naphthenes 
                 1.30 
                 0.00 
                 3.60 
                 0.09 
                 2.24 
               
               
                 C 8  Isoparaffins 
                 1.20 
                 0.00 
                 3.42 
                 0.08 
                 1.98 
               
               
                 C 8  Aromatics 
                 16.60 
                 0.00 
                 0.39 
                 5.86 
                 0.00 
               
               
                 C 9   +  Paraffins 
                 0.10 
                 0.00 
                 0.23 
                 0.01 
                 0.05 
               
               
                 C 9   +  Aromatics 
                 0.50 
                 0.00 
                 0.08 
                 0.17 
                 0.00 
               
               
                 Sulfolane 
                 0.00 
                 99.20 
                 2.17 
                 73.76 
                 0.10 
               
               
                 Water 
                 0.00 
                 0.80 
                 0.02 
                 0.59 
                 2.66 
               
               
                 Total Flow (Kg/Hr) 
                 1000 
                 2100 
                 284 
                 2816 
                 115 
               
               
                 Temperature (° C.) 
                 75 
                 81 
                 80 
                 61 
                 89 
               
               
                 Pressure (Bar) 
                 6.4 
                 6.4 
                 5.8 
                 5.8 
                 1.1 
               
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                 46 
                 47 
                 48 
                 50 
                 51 
               
               
                   
               
               
                 C 5  Paraffins 
                 1.45 
                 1.26 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 5  Naphthenes 
                 5.90 
                 3.28 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 5  Isoparaffins 
                 1.20 
                 1.01 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Paraffins 
                 11.97 
                 12.37 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Naphthenes 
                 20.32 
                 15.38 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 6  Isoparaffins 
                 16.75 
                 16.15 
                 0.00 
                 0.00 
                 0.00 
               
               
                 Benzene 
                 1.12 
                 0.32 
                 4.56 
                 0.00 
                 0.00 
               
               
                 C 7  Paraffins 
                 4.91 
                 6.31 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 7  Naphthenes 
                 6.90 
                 6.52 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 7  Isoparaffins 
                 23.89 
                 27.26 
                 0.00 
                 0.00 
                 0.00 
               
               
                 Toluene 
                 0.03 
                 0.02 
                 3.43 
                 0.00 
                 0.00 
               
               
                 C 8  Paraffins 
                 1.13 
                 1.76 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Naphthenes 
                 2.31 
                 3.24 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Isoparaffins 
                 2.03 
                 3.03 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 8  Aromatics 
                 0.00 
                 0.28 
                 3.00 
                 0.00 
                 0.00 
               
               
                 C 9   +  Paraffins 
                 0.05 
                 0.18 
                 0.00 
                 0.00 
                 0.00 
               
               
                 C 9   +  Aromatics 
                 0.00 
                 0.06 
                 0.09 
                 0.00 
                 0.00 
               
               
                 Sulfolane 
                 0.03 
                 1.57 
                 88.25 
                 2.76 
                 3.01 
               
               
                 Water 
                 0.03 
                 0.02 
                 0.66 
                 97.23 
                 96.98 
               
               
                 Total Flow (Kg/Hr) 
                 112 
                 396 
                 5501 
                 3.0 
                 206 
               
               
                 Temperature (° C.) 
                 35 
                 68 
                 143 
                 35 
                 61 
               
               
                 Pressure (Bar) 
                 1.0 
                 1.0 
                 1.4 
                 1.0 
                 1.5 
               
               
                   
               
             
          
           
               
                   
                 Stream No. 
               
             
          
           
               
                   
                   
                 52 
                 65 
                 68 
               
               
                   
                   
               
               
                   
                 C 5  Paraffins 
                 1.28 
                 0.00 
                 0.00 
               
               
                   
                 C 5  Naphthenes 
                 3.33 
                 0.00 
                 0.00 
               
               
                   
                 C 5  Isoparaffins 
                 1.03 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Paraffins 
                 12.56 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Naphthenes 
                 15.62 
                 0.00 
                 0.00 
               
               
                   
                 C 6  Isoparaffins 
                 16.41 
                 0.00 
                 0.00 
               
               
                   
                 Benzene 
                 0.32 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Paraffins 
                 6.41 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Naphthenes 
                 6.63 
                 0.00 
                 0.00 
               
               
                   
                 C 7  Isoparaffins 
                 27.69 
                 0.00 
                 0.00 
               
               
                   
                 Toluene 
                 0.02 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Paraffins 
                 1.79 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Naphthenes 
                 3.29 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Isoparaffins 
                 3.07 
                 0.00 
                 0.00 
               
               
                   
                 C 8  Aromatics 
                 0.28 
                 0.00 
                 0.00 
               
               
                   
                 C 9   +  Paraffins 
                 0.18 
                 0.00 
                 0.00 
               
               
                   
                 C 9   +  Aromatics 
                 0.06 
                 0.00 
                 0.00 
               
               
                   
                 Sulfolane 
                 0.00 
                 0.00 
                 99.20 
               
               
                   
                 Water 
                 0.03 
                 1.00 
                 0.80 
               
               
                   
                 Total Flow (Kg/Hr) 
                 390 
                 200 
                 2800 
               
               
                   
                 Temperature (° C.) 
                 42 
                 30 
                 80 
               
               
                   
                 Pressure (Bar) 
                 1.5 
                 2.0 
                 3.0 
               
               
                   
                   
               
             
          
         
       
     
     The foregoing has described the principles, preferred embodiment and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Instead, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of present invention as defined by the following claims.