metaxylene UOP 1999

AROMATICSAND DERIVATIVES MX SORBEXTM PROCESS APPLICATION World meta-xylene production was less than 40,000 metric tons per annum (MTA) in 1970, but increased to approximately 170,000 MTA in 1995. It is expected to be 500,000 MTA by 2000. The early productive capacity of metaxylene was based on an HF-BF3 extraction system. Units built in the USA, Italy and Japan in the late 1960s and early 1970s had an aggregate capacity of 200,000 MTA. The MX Sorbex process, UOP’s latest commercial Sorbex application, recovers meta-xylene from mixed xylene feedstocks. “Mixed xylenes” refers to a mixture of C8 aromatic isomers including ethyl benzene, para-xylene, meta-xylene, and ortho-xylene, which boil so closely together that separating them by conventional distillation is not practical. The MX Sorbex process can be integrated into an existing UOP aromatics complex that includes the ParexTM process. The feed to the MX Sorbex process would, in that case, typically be the Parex unit raffinate product stream, which is depleted of para-xylene and thus rich in meta-xylene. However, the MX Sorbex process is quite flexible and can use a variety of C8 aromatic feeds, including mixed xylenes based on reformate, hydrogenated pyrolysis gasoline, or even mixed xylenes from the TatorayTM process. When processing a typical Parex unit raffinate, the MX Sorbex process can easily produce meta-xylene at 99.5 wt-% purity at 95 wt-% recovery per pass. The MX Sorbex technology has been developed to meet increased demand for purified isophthalic acid (PIA). The growth in demand for PIA is linked to the copolymer requirements for PET bottle resin applications, a market growing at up to 20% per year. Aromatics Complex Para-Xylene Parex Mixed Xylenes MX Sorbex Meta-Xylene Light Ends Xylene Splitter Isomar A9+ Clay Treater Deheptanizer Column of a liquid feed over a solid bed of adsorbent. Feed and products enter and leave the adsorbent bed continuously, at nearly constant compositions. The number of adsorbent beds and bed lines varies with the Sorbex application. At any given time, only four of the bed lines are active, carrying the net streams into and out of the adsorbent chamber. The rotary valve is used to periodically switch the positions of the liquid feed and withdrawal points as the composition profile moves down the chamber. A pump provides the liquid circulation from the bottom of the first adsorbent chamber to the top of the second. A second pump provides circulation from the bottom of the second adsorbent chamber to the top of the first. In this way, the two adsorbent chambers function as a single continuous loop of adsorbent beds. The MX Sorbex process operates with an isothermal bed of a solid adsorbent. All process streams are in the liquid phase. Fresh feed is raised to the appropriate process temperature by conventional heat exchange, filtered, and pumped to the adsorbent chambers via the rotary valve. Meta-xylene is separated from the feed in the adsorbent chambers and leaves the adsorbent section in the extract line via the rotary valve. The dilute extract is then fractionated in the extract column to produce 99.5 wt-% meta-xylene as the bottoms product. The desorbent is taken overhead and recirculated back to the adsorbent section of the unit. All the other components present in the feed are rejected in the adsorbent chambers and leave in the raffinate line via the rotary valve. The dilute raffinate is then fractionated in the raffinate column to recover desorbent. As in the extract col- PROCESS DESCRIPTION The MX Sorbex process is part of UOP’s family of Sorbex adsorptive separation processes. Sorbex technology is UOP’s innovative adsorptive separation method for highly efficient and selective recovery, at high purity, of molecular species that cannot be separated by conventional means of fractionation. Unlike conventional chromatography, the continuous Sorbex process simulates the counter-current flow The basis for product values reflects September. b.5 20.6 Rotary Valve meta-Xylene Rich Feed Line Flush Raffinate Extract 220 negligible 15 235 5 8 14 18 45 280 55 335 64. initial adsorbent inventory costs and process license fees. % Payout period.5% of invest. Il 60017-5017 . $MMb Production Costs $/MT Meta-xylene Raw material less by-products Consumables Utilities Variable Cost of Production Labor Maintenance (1. as noted. It is offered solely for your consideration.) Overhead Interest on working capital Fixed Cost of Production Cash Cost of Production Capital charges Net Cost of Production Economic Parameters Gross profit. Total plant investment includes ISBL erected costs. 1999 USGC spot prices for meta-xylene.5 13.0 1. $MM/yr Pretax ROI. All rights reserved. yr 100 925 61. the MX Sorbex process can use a variety of C8 aromatic feeds. UOP 2699C-19 899AD1T TM UO P L L C 25 East Algonquin Road Des Plaines. interest during construction at 10%/yr over two years. with both para and meta depleted xylenes streams valued at $15/mt less than USGC mixed xylenes spot prices ($235/MT).000 MTA of meta-xylene is shown at right.0 96 1. These units represent an aggregate production of 263.5 59. which exceeds the existing HF BF3 technology installed nameplate capacity. MX Sorbex Feed Basis C8 Aromatics Distribution Meta-xylene Ortho-xylene Ethylbenzene Para-xylene Wt-% 65.MX Sorbex Process Adsorbent Chambers Economic Evaluation Basis Meta-xylene product rate. $/MTa Total plant investment. a. the desorbent is taken overhead and recirculated back to the adsorbent section.04 Raffinate Column Extract Column Desorbent Raffinate to Storage or Isomerization m-Xylene Product umn. This information is not to be taken as a warranty or representation for which UOP assumes legal responsibility nor as permission or recommendation to practice any patented invention without a license. KMTA Meta-xylene. off-sites allowances at 30% ISBL costs. contact your UOP representative or UOP at: Phone: 1-847-391-2000 Fax: 1-847-391-2253 The economic summary below gives a pretax ROI of 190% and a payback time of six months for an integrated plant. The feed to the MX Sorbex process is the Parex unit raffinate product.0 As of mid-1999 there are four MX Sorbex units in operation. ECONOMICS Typical performance data for an MX Sorbex process unit producing 100. This example assumes the MX Sorbex unit is integrated within an existing UOP aromatics complex with a Parex unit. FOR MORE INFORMATION For more information.000 MTA of meta-xylene. However. uop ©1999 UOP LLC. $MM/yr Pretax profit.