Abstract: Recovering a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a lean solvent stream containing the selective solvent, measurable amounts of heavy aromatic HCs, and polymeric materials that are generated in an extractive distillation (ED) or liquid-liquid extraction (LLE) process. At least a portion of the lean solvent stream is contact in a solvent clean-up zone with a slip stream from the HC feed stream of the ED or LLE process or an external stream. The HC feed stream, such as pyrolysis gasoline or reformate, contains significant amounts of benzene and at least 50% polar (aromatic) HCs and serves as a displacement agent to remove the heavy HCs and polymeric material from the lean solvent stream. A magnetic filter can be used to remove the paramagnetic contaminants from the lean solvent.

Abstract: Recovering high purity benzene from hydrocarbon feedstock containing aromatics and non-aromatics is implemented by simple and low-cost modifications to conventional extractive distillation columns (EDCs). Methyl cyclohexane (MCH) that is generated through non-selective hydrogenation of toluene in hydrodesulfurization (HDS) units is a major contaminant in benzene production. To meet MCH specifications, often times the extractive distillation (ED) process for recovering purified benzene is operated with excessive benzene loss to the overhead raffinate stream, producing a lower quality non-aromatic product.

Abstract: A magnetic filter employs a magnetic core assembly that incorporates a plurality of exchangeable holder sleeves, each enclosing permanent magnets. Neither the sleeves nor magnetic bars are mechanically fixed to the filter housing. The magnet bars and holder sleeves are individually accessible. The number of holder sleeves in the magnetic core assembly is flexible. The magnetic filter in equipped with a screen that partially encloses the elongated holder sleeves to treat streams that contain degradation sludge, iron containing particles or flakes, and non-magnetic polymeric materials. In operation, a feed stream initially contacts the magnetic core assembly where paramagnetic contaminants become deposited onto the exterior surface of the holder sleeves under direct influence of strong magnetic field generated by the magnet bars. The mesh screen cylinder subsequently captures non-magnetic and weakly magnetic contaminants of a certain size before the cleaned stream exits the magnetic filter.

Abstract: A method for cross connecting the lean solvent supply lines between the liquid liquid extraction (LLE) and the extractive distillation (ED) processes thereby using the LLE column as the outlet for removing accumulated heavy hydrocarbons (HCs) and polymeric materials from the solvent loop of both processes to maintain their solvent performance. The unique capabilities of the LLE column in rejecting heavy HCs from the solvent into a raffinate product stream that leaves the system enable the removal of the accumulated heavy HCs and polymeric materials from the closed solvent loop of the ED process when their lean solvent loop are cross connected. Cross connection requires minimum equipment change. In the revamped system, the solvent recovery column (SRC) in LLE process supplies lean solvent for the extractive distillation column while the SRC of the ED process supplies lean solvent for LLE column.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: A magnetic filter employs a magnetic core assembly that incorporates a plurality of exchangeable holder sleeves, each enclosing permanent magnets. Neither the sleeves nor magnetic bars are mechanically fixed to the filter housing. The magnet bars and holder sleeves are individually accessible. The number of holder sleeves in the magnetic core assembly is flexible. The magnetic filter in equipped with a screen that partially encloses the elongated holder sleeves to treat streams that contain degradation sludge, iron containing particles or flakes, and non-magnetic polymeric materials. In operation, a feed stream initially contacts the magnetic core assembly where paramagnetic contaminants become deposited onto the exterior surface of the holder sleeves under direct influence of strong magnetic field generated by the magnet bars. The mesh screen cylinder subsequently captures non-magnetic and weakly magnetic contaminants of a certain size before the cleaned stream exits the magnetic filter.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: Recovering high purity benzene from hydrocarbon feedstock containing aromatics and non-aromatics is implemented by simple and low-cost modifications to conventional extractive distillation columns (EDCs). Methyl cyclohexane (MCH) that is generated through non-selective hydrogenation of toluene in hydrodesulfurization (HDS) units is a major contaminant in benzene production. To meet MCH specifications, often times the extractive distillation (ED) process for recovering purified benzene is operated with excessive benzene loss to the overhead raffinate stream, producing a lower quality non-aromatic product.

Abstract: An improved solvent regeneration system for extractive distillation and liquid-liquid extraction processes capable of effectively removing heavy hydrocarbons and polymeric materials that otherwise develop in a closed solvent loop. The improved process employs a light hydrocarbon displacement agent, which is at least partially soluble in the solvent to squeeze the heavy hydrocarbons and polymeric materials out of the solvent, with virtually no additional energy requirement. It has been demonstrated that the light non-aromatic hydrocarbons in the raffinate stream generated from the extractive distillation or the liquid-liquid extractive process for aromatic hydrocarbons recovery can displace not only the heavy non-aromatic hydrocarbons but also the heavy aromatic hydrocarbons from the extractive solvent, especially when the aromatic hydrocarbons in the solvent are in the C10+ molecular weight range.

Abstract: An improved solvent regeneration system for extractive distillation and liquid-liquid extraction processes capable of effectively removing heavy hydrocarbons and polymeric materials that otherwise develop in a closed solvent loop. The improved process employs a light hydrocarbon displacement agent, which is at least partially soluble in the solvent to squeeze the heavy hydrocarbons and polymeric materials out of the solvent, with virtually no additional energy requirement. It has been demonstrated that the light non-aromatic hydrocarbons in the raffinate stream generated from the extractive distillation or the liquid-liquid extractive process for aromatic hydrocarbons recovery can displace not only the heavy non-aromatic hydrocarbons but also the heavy aromatic hydrocarbons from the extractive solvent, especially when the aromatic hydrocarbons in the solvent are in the C10+ molecular weight range.

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.

Abstract: Extractive distillation processes whereby water-soluble extractive distillation (ED) solvents are regenerated and recovered employ improved operations of the extractive distillation column (EDC) so that polar hydrocarbons are recovered and purified from mixtures containing polar and less polar hydrocarbons and measurable amounts of hydrocarbons that are heavier than intended feedstock and/or polymers that are generated in the ED process. The improved process can effectively remove and recover the heavy hydrocarbons and/or remove polymer contaminants from the solvent in a closed solvent circulating loop through mild operating conditions with no additional process energy being expended. With the improved process, the overhead reflux of the EDC may be eliminated to further reduce energy consumption and to enhance the loading and performance within the upper portion of the EDC, especially when two liquid phases exists therein.

Abstract: A process for recovering polar hydrocarbons from non-polar hydrocarbons, such as aromatics from non-aromatics, naphthenes from paraffins and isoparaffins, or olefins from paraffins and isoparaffins, in feed mixtures containing at least a measurable amount of heavier hydrocarbons. This improved extractive distillation (ED) process recovers aromatic hydrocarbons including benzene, toluene, and xylenes from the C6-C8 petroleum streams containing a measurable amount of C9+ hydrocarbons. The ED process also recovers benzene and toluene from the C6-C7 petroleum streams containing a measurable amount of C8+ hydrocarbons. The ED solvent utilized to recover and purify the aromatic hydrocarbons from the petroleum stream with a heavier than intended feedstock of hydrocarbons is also regenerated and recovered.

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.

Abstract: Extractive distillation processes whereby water-soluble extractive distillation (ED) solvents are regenerated and recovered employ improved operations of the extractive distillation column (EDC) so that polar hydrocarbons are recovered and purified from mixtures containing polar and less polar hydrocarbons and measurable amounts of hydrocarbons that are heavier than intended feedstock and/or polymers that are generated in the ED process. The improved process can effectively remove and recover the heavy hydrocarbons and/or remove polymer contaminants from the solvent in a closed solvent circulating loop through mild operating conditions with no additional process energy being expended. With the improved process, the overhead reflux of the EDC may be eliminated to further reduce energy consumption and to enhance the loading and performance within the upper portion of the EDC, especially when two liquid phases exists therein.

Abstract: The present invention relates to a process for recovering polar hydrocarbons from non-polar hydrocarbons, such as aromatics from non-aromatics, naphthenes from paraffins and isoparaffins, or olefins from paraffins and isoparaffins, in feed mixtures containing at least a measurable amount of heavier hydrocarbons. According to the invention, an improved extractive distillation (ED) process is disclosed for recovering aromatic hydrocarbons including benzene, toluene, and xylenes (BTX aromatics) from the C6-C8 petroleum streams containing at least a measurable amount of C9+ hydrocarbons. The invention also relates to an improved ED process for recovering mainly benzene and toluene from the C6-C7 petroleum streams containing at least a measurable amount of C8+ hydrocarbons.