Document oDb2be1RY6293b6xM97vjZ9EE

\ \\ I i ABDOO184025 PVC PLANT/R&E MEETING NOVEMBER 28-29, 1982 ABERDEEN, MISSISSIPPI REACTOR INERTS/VENTING Analysis of potential sources of inerts in.PVC reactors which would cause venting shows CO^ to be the inert present in greatest amounts. This is followed by nitrogen in much smaller quantities. The major source of CO in a reactor appears to be the monomer and RVCM. A process tor removal of CO from the monomer recovery system would eliminate much of the reactor venting problems. I. Composition of Inerts The reactor inerts are primarily CO^ and nitrogen. Oxygen that is initially present is consumed early in the run. There are also traces of ethane, ethylene, CO, and methyl chloride, plus other light hydrocarbons. These are not a problem at their present levels. I. Inerts Sources Monomer/RVCM This is the single largest potential source of inerts in a reactor. As all vapor from a reactor must pass through the recovery system, inerts are contacted with and dissolve in the RVCM and probably the fresh monomer. CO. Is particularly soluble in VCM and within the range of operating conditions of the RVCM system, it could comprise several percent of the liquid RVCM. A recent liquid sample of RVCM from the new module at Aberdeen was 1.9 mole percent C0_. Nitrogen also has some solubility in VCM but is well below that of CO^. Initiator Release of CC^ from the breakdown of initiator is probably the main source of CO^ dissolved in the monomer. However, initiator is a secondary source of inerts for a particular batch. Table I lists the maximum CO^ release for various initiators. Actual CO generated by initiators is probably less than listed and wifi vary between types. ABDOO184026 Reactor Evacuation About 0.3 mole of air is left in the reactor after evacuation. This is the major source of nitrogen and oxygen. Charge Water About 20 ppm dissolved air may be present in the charge water. Analysis of the Aberdeen water gave an average of 50 ppm Total Inorganic Carbon as C0_. This would be the maximum C02 released from carbonates in the water. I I . Examp 1e The following example illustrates the relative magnitudes of the inerts sources. Reactor Charge: 50,000 lb VCM, 20% RVCM 70,000 lb H2 5 gallon L -223 Init i ator Source Quantity RVCM (2% C02) q Receiver at 70 F, 65 psig Assumes no C02 in fresh monomer 141 lb CO 9 lb N2 1nitiator-Maximum 6.7 lb C02 Evacuation 7.3 lb N 2.4 lb 02 Water-Dissolved Air Carbonates, Maximum 1 lb N 0.35 lb 02 3.5 lb co2 Totals C0_ 151.2 lb N2 17.3 lb 0 2.7 lb 171 .2 lb I f fresh monomer has inerts dissolved in it, via the recovery system, the CO^ and will be much higher. R