Document 6BejNn0KxmELj8npkNMnMaeg3

.. t ; ** * Monsanto '. *FROM (NAME LOCATION) K. E. Boucher, Krummrich . ^ OATE : SUBJECT 't REFERENCE : July 22, 1971 , SIMULATION OF AROCLOR/MONOCHLOROBIPHENYL DISTILLATION cc= W. C. Engman^g^ 0. A. Meyer-^J^^ TO : R. M. McCutchan > .. ` A simulation study of the new Aroclor distillation column was completed. This work was done to 'troubleshoot' the column before the August start-up. Aroclor 1016: No particular difficulties were found with the distillation of Aroclor 1016. Both the. cycle time and heat input were larger than expected, however, this may be explained by the higher reflux ratio used for the simulation. Some weeping may occur at the top of the column but appears not to be serious. Tables 1 through 5 show results of the simulation Mon00oMfh0ht&> ' Monochlorobiphenyl: The distillation of Monochlorobiphenyl may prove to be more difficult. Some weeping may occur throughout the entire column, lowering the expected efficiency. Most serious is the determination of when to stop the forecut after chain feeding is completed. Using a 2.2 hour cycle between stopping chain feeding and starting the collection of product gave a product high in biphenyl. To prevent rework, a second simulation using a 4.6fchour period successfully produced pro duct with 16% biphenyl^weight. Tables 4 through 7 show results of this simulation. Recommendations: .. 1. If weeping is actually extensive while producing Monochlorobiphenyl, consider lowering the column pressure. 2. To avoid rework of Monochlorobiphenyl, start collecting the product only after the biphenyl content has signifi cantly dropped (to about 55/). Figure I shows the rela tive sharpness of the separation prior to collecting the product. It is due to the rapid change in biphenyl Just ' before product collection that careful control of the cut-off point for the forecut Is necessary. /tm . It&t&uJL, DSW 297575 K. E. Boucher Technical Services Department .. STLCOPCB4067486 . TABLE I AROCLOR 1016 OPERATION CONDITIONS - REDUCED VAPOR RATE Column Vapor rate lbs/hr Cycle Time, Distillation only Design 33,000 56.25 Simulation 66.6 Still Pot . Initial Charge - lbs End "High Boilers" wt-lbs Temperature - C Charge . Initial B.P. Pinal 104,000 95,000 160 260C 140 mm 300C (max) 104,000 92,000 150 255C 140 mm 278 Column Total Column Overheads Distillation Rate @3:1 R/D - lb/hr - actual external R/D - actual internal R/D Distillation Rate @5:1 R/D - lb/hr - actual external R/D - actual internal R/D 423,740 8,250 3/1 . 5,500 5/1 438,000 8,250 2/1 3.25/1 5,500 3/1 5.7/1 Condenser ft BfV' /h&- Cooling Duty at 3:1 R/D Cooling Duty at 5:1 R/D Amount subcooling - C 6.8 6.0 160 Reboiler Furnace M BTU/Hr Heat Duty at 3:1 R/D Heat Duty at 5:1 B/D 4.3 5.1 4.9 DSW 297576 STLCOPCB4067487 TABLE 2 SIMULATION AROCLOR 1016 CYCLES - HOURS .* Cycle Time Cumulative Feed, 3/1 R/D Feed, 5/1 R/D Boil Down 25.9 38.8 1*9. 25.9 64.7 . 66.6 TABLE 3 ` AROCLOR 1016 DISTILLATION SIMULATION COMPOSITION # BY WEIGHT Ortho . Para 4,4' 3,3' CB 3 CB 4 CB 5 ` Feed 0.6 0.2 - 27.4 4.4 37.7 23.3 6.4 Product 0.8 0.3 38.9 6.1 52.1 1.8 .- DSW 297577 STLCOPCB4067488 7/1) A // UJ -Cva E~^. - VS i. 5* Al V oo oo '3o~ O CJ 7A <V5 /Vdf / % 3 7o^V DSW 297580 STLCOPCB4067489