Document G56XNnZXx45aL0Zv4N8XJmw7m

5305 RESIDUAL VCM REDUCTION ABERDEEN PVC PLANT March 26, 1990 Work by: R. C. Tebo Process Engineer Engineering Department and by: D. E. Knittig Process Engineer Engineering Department Approved by: P. C. Schirber Senior Process Engineer Engineering Department -+h p ' ' hwtNj'MiPi fli-rt VAB.0001097510 Hill ^ AEERDEEN PVC PLANT Table of Contents I. Introduction ........................................................................................................................ 1 II. Recommendations ............................................................................................................... A. Major Effect ................................................................................................ B. Moderate Effect ........................................................................................ C. Unknown Effect ........................................................................................... 2 2 4 5 III. Observations/Conclusions ...................................................................................... 6 IV. Discussion............................................................................................................................. 8 A. Plant Air Reliability ........................................................................ 8 B. Resin Particle Size ............................................................................. 9 C. Recipe Optimization ............................................................................. 10 D. Heated Silo Air ......................................................................................... 11 E. Small Blend Tank Heating.................................................................. 12 F. Blend Tank Agitation/Aeration.................................................. 13 G. Dryer Controls ........................................................................................... 14 H. Silo Operation Improvement .......................................................... 16 I. Silo Aeration Improvements...........*............................................. 16 J. Bench Scale Silo.................................................................................... 17 K. Reactor Stripping ................................................................................... 17 L. Nested Experimental Designs ....................................................... 18 1. Blend Tank Nesting .................................................................. 19 2. Silo Nesting................................................................................... 20 V. Summary ................................................................................................................... VI. Appendices A. Plant Wet Air Survey B. Resin Particle Size and Its Effect on 5305 C. Heated Silo Air D. Heated Blend Tanks E. Blend Tank Agitation/Aeration F. Dryer Controls G. Silo Aeration H. Reactor Stripping I. Nested Experimental Designs I.................. Ip'"'! .if I-..'. .-.I, .. .. H w<4#p+fWT ' Jtfc-h, , iji|| * H** ...................... ^W Hill mnLWPir^tMIM iUifc limiiM-rthu VAB.0001097511 NT PimrjHhim*--t .... ............................. A RESIDUAL VCM REDUCTION I. Introduction A competitor has guaranteed American Mirrex that 80% of its resin will have less than 250 ppb RVCM. Prior work has shown that Vista can produce 250 ppb or less RVCM resin only one third of the time during the winter months. The short term goal of this project is to provide American Mirrex with 250 ppb RVCM 5305 resin. The longer term goal is to consistently produce 5265 and 5305 resin with RVCM less than 250 ppb. Furthermore, the business area believes that eventually RVCM levels will be targeted down to 10 ppb in 5265 and 5305, and 100 ppb in 5385 and 5415. Historically, RVCM in Vista's resin is highly variable. There is a seasonal trend for RVCM, with RVCM being the highest during the winter months and lowest during the mid summer. Aberdeen can consistently meet the short term 250 ppb RVCM target during the summer months, but cannot during the winter and spring. To better illustrate, historical RVCM data is shown below. Table I Historical RVCM Data Summer 1989 5265 5305 Winter 1988 5265 5305 70 ppb 100 ppb 440 ppb 340 ppb Control Limits Lower 120 ppb 180 ppb 20 ppb 20 ppb 650 ppb 550 ppb 220 ppb 130 ppb For the last four months, PED and Aberdeen have been conducting extensive research into RVCM reduction. Three major test runs were completed between November 1989 and February 1990. Two experimental designs were done to determine the major factors of 5305 RVCM removal. This report is the culmination of that work. H-Mi i i I.-. . -r >r i. < .in. x -h ** tiff* (Mhi*-: h. rp, ^H:4i 4 i I T ' M 'I I'! l M || I i> Hi ^lUBI |l VAB.0001097512 II. Pft^ommdations The following are recommended ways to reduce RVCM in 5305. These recommendations are classified into three categories: A) those with a major effect on RVCM, B) those with a moderate effect on RVCM, and C) those with an unknown effect on RVCM. A. Major Effect The following is a list of recommendations which are believed to have a major effect on RVCM removal in 5305. Some of these recommendations, however, do not have an addj-tive RVCM removal effect with othersatid^_dscretion shoulcLJae UBed^iir^determining-whart^recommendations--are used*" i-r 1. Plant Air Reliability - Aberdeen's wet air system reliability needs to be improved. Blend tank and silo aeration account for nearly all of the post reactor RVCM removal in the process. With the current systems, Aberdeen's aeration air is in very tight supply. The blend tanks, silos, and activators do not consistently get the required amount of air needed for their purposes. This results in higher final product RVCM. P\ \; ) 2. Resin Particle Size - Aberdeen should evaluate the effect of changing the 5305 particle size specification. RVCM has a strong correlation with resin particle size. A 20 micron decrease in targeted particle size (from 140 to 120 micron) will result in a 35% decrease in product RVCM. Customer quality specifications need to be reevaluated to determine if Aberdeen can shift its _________________________ 1 n a * ^ 3. Recipe Optimization - A detailed experimental design should be conducted in Aberdeen to determine optimum conditions for 5305. Variables should include Polivic, F-50, GH-20, initiator and kill charge amounts. These variables should be looked at to optimize CPAs, CoVs, RVCM, color and glassies. Morphology characteristics could also be studied by R&D by using their microbalance. 4. Heated Silo Air -- An air heater should be installed to heat silo aeration air to 150F. Heating the silo air helps reduce residual RVCM by up to 25%, and does not have a detrimental not resin color or contamination. pixf.+j. - .r:p-i , _ .w,. u-i- i ,i r I-*- 1 ...............-*' ,-Mi`Hfr -If-Hr-. . . 'i r-pi- . * hi--. r .. r^ ."4V: -v.T'1 "5---t1 ip .i.i*riir . -nln, *j'.*l** >f NH i|M I1!' I VAB.0001097513 A 5. Blend Tank Keating - Aberdeen should rinse the 5305 reactors with hot water. Increasing the small blend tank temperature improves RVCM removal in the slurry. By rinsing the reactor with hot water, blend tank temperatures could be raised by 10 to 15 *F. Hot water rinsing to the blend tanks can improve slurry RVCM by 20%. To further reduce blend tank RVCM, Aberdeen should install a blend tank steaming system. Continuously steaming the blend tanks to maintain temperature above 150"F during the 12 hour aeration period also helped reduce slurry RVCM. Steaming the blend tanks reduced slurry RVCM out of the blend tanks by 50% during January test runs. However, the effects of blend tank steaming and hot water rinsing are not additive. Steaming and hot water rinsing will not reduce RVCM beyond the 50% claimed by steaming 6. Blend Tank Agitation - Aberdeen needs to investigate ways to improve small and large blend tank agitation. With the current systems, a large resin heel forms in the tanks which does not get aerated. Improved blend tank agitation and/or aeration would improve slurry blend tank RVCM. Increased agitation/aeration by increasing air rates by 50% resulted in a 50% reduction in blend tank RVCM. Further improvement should be expected if aeration air flow is increased for the large slurry blend tank T-407 7 Dryer Controls - Rotary dryer controls should be improved. The 5305 dryers (dryers 6 and 8) currently have the most difficulty controlling temperature. Improved dryer controls would reduce temperature swings in the dryers. Tight temperature control would cause RVCM variability out of the dryers to decrease. Reduced RVCM variability out of the dryer would significantly improve resin RVCM variability in the silo and consistency of the final product. T" r. * -V- -V ? - ..s II ri I li I i bl i > . |i hif liL >ft9-T VAB.0001097514 MJI A B. Moderate Effect The following recommendations are believed to have a moderate effect on reducing product residual VCM. 1. Reactor Stripping - Temporary systems have been set up to allow a small flow of cooling water to the condenser during batch stripping. By supplying some cooling to the system, steam flow to the reactor will increase to maintain temperature setpoint. In reactors D-700 and D-745, there has been a 50% reduction in reactor RVCM with the new stripping procedures. However, reactor RVCM has only a moderate effect on product RVCM due to an RVCM dampening effect in the blend tanks. A permanent system needs to be installed to help reduce slurry RVCM and plant VCM stack emissions. 2. F-50 Consistency - Aberdeen should investigate ways to decrease F-50 variability. In order to make consistently low RVCM, tight particle size control is essential. Inconsistent F-50 activity compounds the problem. 3 Aeration Indication -- Blend tank sparger pluggage must be minimized. Installation of air flow meters on the large and small 5305 blend tanks would give early detection of sparger pluggage. Also, tank air flow meters would reduce RVCM variability by improving air distribution to all of the tanks. 4. Silo Aeration Improvements - RVCM can be reduced by improving silo operation. Automatic air flow control is needed on every 5305 silo, and yard operators need to follow 5305 railcar unloading procedures carefully. Silo air valve indication lights need to be repaired on the dryer control panel also. 5. silo Air Piping Changes - Piping changes to the aeration air lines at the silos would result in more consistent aeration to each silo. Because of the current piping setup to the silos, some silos get better aeration than others. Piping changes would allow a more uniform air distribution to all the silos. . '.fin * |l 1.^1 IP|I. '! > 1r I. I Pf1 y.r -j| J*r ` hi ir-M . l ' itt 4t<mp Illlh-- Ml 1 m* inmujEsm VAB.0001097515 A 6. Silo Air Pressure Control - Air pressure to the silos is now controlled by a manual valve. The manual valve does a poor job controlling air pressure to the silos. Replacing the existing inoperative pressure control valve would improve silo aeration and lower RVCM. 7. Silo Air Distribution - RVCM levels and variability can be reduced by improving the air distribution through the silos. With the present system, heavy air channeling occurs and can be witnessed by observing the large air perks" at the top of the silo. The perks are all in the center of the silo. The silo's cone and outer edge do not get aerated as fully as the middle. C. Unknown Effect The following recommendations have an unknown effect on RVCM. However, it is believed that they do have merit and good potential for improving residuals. 1. Bench Scale Silo -- Based on experience from the last series of test runs, it is believed that there is an optimum air flow rate. By testing a bench scale silo, many things can be learned and applied, such as optimum air flow, air temperature, and air distribution. 2. Increased Aeration of First Batch - RVCM seems to always be at its highest at the beginning of a campaign. One reason for this may be that the first batch of slurry gets a bare minimum amount of aeration in the large blend tank. It is recommended that if possible, the first batch of 5305 be held in the large blend tank for four to eight hours before the dryers are started. 3. Ethanol Based Kill -- There is a theory claiming that ethanol, put in the reactor, oxidizes to form an aldehyde which is hard to strip and masks the VCM peak on the gas chromatograph. In December, ethanol was being used in the Isonox kill system for 5305. At this time, Mirrex noted that they saw a second peak on their gas chromatograph which was partially masking VCM. No evidence was found during the test runs to support or oppose the claim. However, just to be safe, it is not recommended that ethanol be used in the kill system. h .r -ii-f-i r T- H- J . w-L-VI- wi.i i:v t n~4* : -Tccipi |< i i -f n-t-- - j-i K-"- VAB.0001097516 Mxftr 4. Continuous Silo Baghouse Pulsing - Some of the 5305 silos had baghouse problems resulting in continuous air backflow to the filter. When the silo hatch was opened, it was noted that these silos were under a small amount of pressure. These silos also could not get obtain adequate aeration flow rates and consequently had higher RVCM values. 5. Blend Tank Fume Exhausters - One observation during the RVCM test runs was that the fume exhauster was pulling air out of some blend tanks better than others. The west row of tanks seemed to have a higher vacuum on their exhaust line. It was also noted that the west row of tanks cooled off quicker than the east side tanks. These temperature differences could contribute to blend tank RVCM variability. Details about some of these recommendations can be found in the discussion portion of this text. Ill. Observations/Conclusions Most of the major conclusions were addressed in the recommendations section of this report. Listed below are some further conclusions and observations pertinent to RVCM removal. 1. Reactor residuals have a positive effect on small blend tank pumpover residuals. For adequate results, reactor RVCM should consistently be below 120 ppm. .2 Reactor particle size and RVCM do not vary during the reactor dump cycle. 3. RVCM removal in the blend tanks fits a^non-Fickean) diffusion curve. R&D microbalance resuits aisn^Krm non-Fickean behavior for 5305. 5385 and 5415 show Fickean diffusion behavior. 4. For most efficient RVCM removal in the blend tanks, the small blend tanks should be aerated for at least 12 hours. Any further aeration beyond 16 hours in a cold blend tank does not significantly reduce RVCM. v .4*1 i-Pi:--j : <*4Tv a s'f* r -II -M-c-M-m-rsi .***. l .-- - -- i~---rr nr rin f n it vir-r-im ~i -pan - in < Miph^H!- r^=rtl mm*\ Will .............................. .. VAB.0001097517 A 5. Of the total RVCM variation in the blend tanks, one third of it is attributable to sampling and lab testing. The remaining two thirds of the overall variation comes from the process itself. 6. Blend tank residuals have a positive effect on dryer RVCM. Lower blend tank RVCM reduces dryer and product RVCM. Large blend tank RVCM should be targeted at close to one ppm as it is fed to the centrifuge. 7. Small blend tank RVCM varied during pumpover to the large blend tank. Pumpover RVCM was at its highest during the very start and end of the pumpover. There was no particle size variation during pumpover. 8. Large blend tank T-407 has only four spargers in it. This allows for dead spots on the bottom of the tank. If a sparger were to plug, the dead spot would become very large. All the blend tanks use only a fraction of the recommended amount of air needed for complete agitation. CPAs were run on dryer particle size screen cuts to see if there were any relationship. The results gave a v t parabolio^curve with a minimum CPA at 100 mesh. The overall_composite^ however, had an even 1 nwr CPA than the lOO^mesh cut. ------------- .f \ i r i coefficient of variance . However, the correlation is not always in the same direction. During August 1989 and February 1990 there was a correlation. During July 1989, however. was a All correlations had greater than 95% confidence limits. 12. During the test runs, there was a positive correlation between dryer moistures and dryer RVCM. Improved dryer controls giving more consistent moistures would reduce RVCM variability. 13. RVCM removal in the silos does not seem to follow a smooth removal curve. This may be explained by a. severe air channeling in the silos b. high dryer variability and mixing in the silos c. frontal chromatography I i r i. Hi mLt 'HkltTfl.'Itt I - H `L.'l-'.-p p. L l.* -I h- Jl h* I fl^.' 'HI-1 ; J-| - ( VAB.0001097518 At 14. There is a significant amount of drying for 5305 in the silos. After 24 hours aeration, the resin moistures are reduced by over 50%. 15. Silo aeration removes at least 30% of the remaining RVCM out of the dryers. Silos should aerate at least 24 hours. However, no additional RVCM removal is seen with cold air after 30 hours aeration. 16. RVCM measured by the Aberdeen lab often matches the lab reported by American Mirrex. Differences in * s and Mirrex RVCM numbers is due to weathering and sample location. sampl from the bottom of the car while Mirrex often samples from the top of the car. 17. Lab RVCM testing for dry resin samples had very little variability. Slurry lab RVCM testing had a very large variability. IV Discussion A. Plant Air Reliability With the current systems, Aberdeen's aeration air is in very tight supply. Frequently, the air demand is high enough that air flow to the silos, blend tanks, and activators is insufficient. When this occurs, RVCM greatly increases. Silos and blend tanks get minimal aeration resulting in higher RVCM. High air demand results in lower system air pressure. Low air pressure limits the efficiency of the dryer activators. Low air pressure can also lead to slower resin transfer, plugged lines, and increased sifter overflow. Furthermore, with low air pressure, the blend tank air spargers often plug. In order to adequately aerate the silos, air pressure to the silos must be maintained above 25 psig. Currently, silo aeration air pressure is below 25 psig over 40% of the time. Low air pressure causes insufficient silo aeration and high residual VCM. Aeration in the blend tanks is also inadequate. Blend tank air flow rates are up to 50% lower than recommended for adequate agitation in RQIP. Furthermore, air flow to each of the blend tanks is variable. The blend tank air flow is controlled by a throttling a manual plug valve at each individual sparger. Air distribution to each sparger is unequal, causing RVCM variability and possible sparger pluggage. '.wi, - , J . -.v 1ffi| r NPn li-l^ i- ^ hi l-W-rr-i i~ * i r->+!'i|r- mWm^lMr-iPihi I -.Mtf h. VAB.0001097519 A Because the agitation is insufficient, a resin heel forms in the blend tank (especially in the large blend tank T-407). The resin in the heel does not get aerated and tends to yellow and degrade. Improved blend tank aeration as was provided for in the Blend Tank Mixing Improvement portion of RQIP would help reduce 5305 RVCM, b-color and contamination. A recently completed wet air survey for Aberdeen is attached in Appendix A. B. Resin Particle Size The current target for average particle size of Vista's 5305 resin is 140 micron. However, the average 5305 railcar particle size ranges between 120 and 165 micron. Particle size distributions typically tend to get wider with coarser resin produced. Tight particle size control is important in making low RVCM 5305 resin. Lab results show a strong correlation between RVCM and average particle size in dryer and railcar samples for both summer and winter. In all cases, coarse resin tends to have higher RVCM. In order to test the theory that RVCM is higher in larger particles, several dryer samples were taken and screened into particle size cuts. Each screen cut was then tested for RVCM. In all cases, resin on the 60 and 80 mesh screens had RVCM over ten times higher than 200 mesh and pan resin. Results were duplicated using lab dried reactor dump samples. Table II shows the results of the lab tests for each particle size cut. Table II Dryer RVCM Particle Sise Relationship Particle Size Cut_____________________rvcm Composite 1.1 60 Mesh 4.7 80 Mesh 2.5 100 Mesh 1.4 120 Mesh 0.6 140 Mesh 0.4 200 Mesh o.3 Pan o.1 ' >' 1 ' - r- I-" - I - -l-r-l--* -- 'yw u-Nf-v Ti-n- k.i.w --t-h# - III ft| VAB.0001097520 imnwNiei-- m Jitm << A Using the information on RVCM content for each particle size cut, the improvement in RVCM can be predicted for any particle size distribution. Table III below shows a the expected improvement for different particle size distributions. Since product RVCM is so variable, it is extremely difficult to assign absolute numbers to each particle size cut. Therefore, for the calculated RVCM, each particle size distribution will be compared with the target particle size. The target particle size (140 micron) will be assigned an arbitrary RVCM value of l. \ /7 ^ Table III ,0'n Particle Size Effects on RVCM Viv 1 % on 60/ Calculated Actual Ava Micron CoV 80 mesh DDl RVCM DDm RVCM 120 0.288 3.6% 0.64 0.366 130 0.272 6.8% 0.84 0.505 140 0.189 5.5% 0.90 Target-140 0.284 11.4% 1.00 0.608 150 0.281 17.1% 1.20 0.811 160 0.298 23.7% 1.41 1.487 180 0.357 31.4% 1.87 1.721 n appendix B also illustrate the on RVCM. Table III shows that if the target particle size is shifted to the finer side, a significant reduction in RVCM can be expected. The table also shows that RVCM can be reduced by reducing the particle size distribution (measured by the coefficient of variance - CoV). Both lowering the target particle size and tightening the size distribution are in effect reducing the number of large, high RVCM particles. C. Recipe Optimization Since the RQIP temporary systems have been installed, there has been a lot of work done to determine how the recipe effects resin properties. However, the work done up to now concentrated on what was required to make an acceptable new technology performance resin as soon as possible. For example, Polivic charge amounts have not been changed or investigated since Aberdeen started making acceptable 5305. :* - l t. | n*i rj 9 i-rv-:.. |it L.>r m Fi'hhr -n| i vi^ v i-th: I- -- I I . p-i- H VAB.0001097521 m* Nov that Aberdeen has established a baseline quality for its performance resins, Vista has the opportunity to improve resin quality by optimizing reactor charge recipes. Recipe optimization probably would consist of a detailed experimental design to determine the effects of suspending agents, initiators, and kill agents. The 5305 resin recipe optimization should focus on improving resin color, CPA, RVCM, glassies, and CoV. Morphology characteristics should also be investigated by R&D by using their microbalance. Once 5305 recipe is optimized, Aberdeen should focus on optimizing 5415. D. Silo Air Heating Back in 1986, when Aberdeen was trying to reduce RVCM to below 2 ppm for Nibco, R&D built a bench scale model of a resin silo and performed aeration tests. One test showed that heating silo aeration air helped reduce RVCM in old technology 5265. However, since the increased reduction was minor (10%), no further work was done. One major conclusion to the bench scale tests was that the rate of diffusion was dependent on the resin temperature. Cold aeration air would cool the resin and slow the rate of diffusion. Results of the bench scale test are attached in Appendix C. During the February test runs, a 23 experimental completed which studied the effects of 1) silo aeration air , 2) aeration time, and 3) Xsonox kill amount. showed that air temperature and aeration time significantly reduced resin RVCM. Isonox kill amount (varied from 75 to 125 lb) had no effect on RVCM. In early January 1990, Aberdeen installed a small electric heater The heater was used to heatv the silo aeration air up to 100TF. It was found that RVCM could be reduced by up to 25% in the silos by heating the air. To ensure 5305 quality, during the heated air tests, the lab monitored resin color, contamination, and moisture. Heated air had no effect on resin color or contamination using heated air up to 130*F. Resin moisture levels in the silo, however, were reduced. A ^ i-i rv--'---a-.-j-bti. 4-lf- ..................................................t r him w* > VAB.0001097522 A larger air heater should be installed to heat all the silo aeration air to 150*F. The existing heater is too small and at full aeration rates can only heat the air to 80F in the winter. A larger heater with consistent temperature control would be able to reduce RVCM by at least 25% and also reduce final product variability. Another finding during the silo aeration tests is that silo aeration time has a significant effect on RVCM removal. For best RVCM removal, the silos should be aerated at least 24 hours. No significant RVCM removal is seen after 30 hours aerating using cold aeration air. Results of t Appendix C. by R&D are attached in E. Small Blend Tank Heating One of the experimental designs to lower product RVCM was heating the small blend tanks during the 12 hour aeration a-- ___________- ^1 ^ The 2 experimental design was done using blend tank steam heating, hot water reactor rinsing, and blend tank aeration time as the three variables for study. Steam heating the small blend tanks reduced small blend tank RVCM by 50%. Rinsing the reactors with hot water instead of cold water reduced the blend tank RVCM by 20%. As should be expected, hot water rinsing in combination with blend tank steam heating did not reduce blend tank RVCM beyond the 50% realized with steam heating alone. The benefits of steam heating and hot water rinsing are not additive. Currently, reactor D-700 and D-745 are dumped and rinsed with cold water to the small blend tanks. The slurry is then aerated for 12 hours prior to being pumped over to the large blend tank T-407 to be dried. The small blend tank temperature is about 150F after rinsing. In the winter, after 12 hours aeration, the tanks can cool down to as low as 100*F (typically 135'F) . The cooling of the small blend tanks slows the RVCM removal. During the test runs, blend tank heating was not supposed to actually heat the blend tanks, but to keep them from cooling off. By rinsing the reactor with hot water instead of cold water, the blend tank temperature after rinsing was 165*F and the tank cooled down to 145F after 12 hours aeration. Steam heating the blend tanks kept the temperature of the blend tank temperature constant throughout the 12 hour aeration period. Steam heating kept the temperature above 160flF when A If 1 i l il 'h I'TWH ftMMHEI. I.unyrn--|* Hwjmypi JiWUM ** ijwt* mt LWhj || i it: VAB.0001097523 h 1 rinsing with hot water, and 150*F when rinsing with cold water During the blend tanks heating tests, resin color and contamination were closer 'tored. No increase in contamination or b-color een during the test. Due to practicality, only one set of blend tanks could be used for the test. because only one set of tanks were used, and the slurry was blended, no attempt was made to determine the effect steam heating had on dryer RVCM. The small blend tank steam heating test also studied the effect of aeration time on blend tank RVCM removal. It was discovered that with no blend tank steam heating, RVCM variability was high. It was also discovered that there was effective RVCM removal in the blend tank for up to 12 hours aeration. Further aeration beyond 16 hours gave very little RVCM removal. The steam heated blend tanks had a much lower RVCM variability and a somewhat different RVCM removal curve. When the blend tanks were steamed, RVCM removal followed a removal curve very similar to a non-Fickean diffusion curve. R&D microbalance studies have shown that diffusion 5305 is non-Fickean in nature. All this information implies that when the blend tanks are steamed, the rate limiting factor for RVCM removal in the blend tanks is VCM diffusion out of the PVC particle. When the blend tanks are not heated in any way, VCM stripping out of the water may be limiting the rate of RVCM removal. Appendix D contains the results of the experimental design, as well as results from the extensive sampling program done to determine blend tank RVCM removal efficiency. F. Blend Tank Agitation/Aeration With the present blend tank aeration system, air distribution is such that a large resin heel forms in the tanks. This heel does not get aerated and therefore contains high RVCM levels. The heel can degrade and cause high b-color and contamination. Improved blend tank agitation/aeration would potentially improve blend tank RVCM, b-color, and contamination. Testing in November 1989 showed that increased blend tank air flow improves RVCM removal in the slurry. By increasing air flow rates to the blend tank by 50% , a 50% reduction in blend tank RVCM can be expected. Even further slurry RVCM 13 fti -<r y#n*-CTr .*1B i in inmiinnPiH<Tw VAB.0001097524 w* improvement can be expected if air flow is increased for the large blend tank T-407 also. Aeration in all the blend tanks is inadequate. Blend tank air flow rates currently are up to 50% lower than recommended for adequate agitation in RQIP. Furthermore, air flow to each of the blend tanks is variable. The blend tank air flow is controlled by a throttling a manual plug valve at each individual sparger. Air distribution tc each sparger is unequal, causing RVCM variability and possible sparger pluggage. Blend tank agitation is the worst in the large blend tank T407. T-407 only has four air spargers, although according to the RQIP designs, it is supposed to have eight. Air flow rates to T-407 are well below the recommended rate for complete agitation. Improved blend tank aeration as was provided for in the Blend Tank Mixing Improvement portion of RQIP would help reduce 5305 RVCM and b-color. One of the biggest causes of high RVCM is blend tank sparger pluggage. Blend tank air spargers plug fairly frequently. However, there is no way to readily know when a air sparger is plugged. Air flow meters on the blend tank aeration line would not only show when a sparger is plugged, but would also help provide consistent air flow to all the tanks. Further information about blend tank agitation/aeration and its effect on RVCM is attached in Appendix E. G. Dryer Controls During the months of November 1989, and February 1990 extensive sampling was done to determine the how the process affects RVCM. A major finding was that the magnitude of the process variability of the dryers was one of the largest contributors to overall product variability. It was always known that dryer RVCM fr highly variable. What was discovered highly variable from hour to hour. In change up to 25% within one dryer test variability, as determined fr day to day was that dryer RVCM was , dryer RVCM could cycle. Since the experimental designs, is small, a great deal of process variability is being introduced dryers VAB.0001097525 A There are some other factors that are believed to have a major effect on dryer RVCM, but have not been proven in the field. These include: a. Large Blend Tank Level b. Drying Efficiency c. Individual Dryer Performance d Dryer Temperature It was shown during previous test runs that the slurry solids concentration changes significantly with blend tank level. Maintaining a consistent blend tank level or improving blend tank agitation would ensure a more consistent feed rate to the dryers. In the advent of an external stripping column for 5305, the continuous nature of the process would help keep a consistent blend tank level. In the meantime, efforts should be focused on improving blend tank aeration. It is also believed that individual dryers have different VCM removal efficiencies. This theory could not be because of the high variability of the process and limited number of data points. Presently, dryers 6 and 8 are used to dry 5305. From looking at the dryer temperature , it can be concluded that dryers 6 and 8 Y controlled dryers. The outlet temperature for both dryer 6 and 8 have a cyclic pattern while dryers 4, 5, and 7 have much tighter temperature control. Figures 1 through 4 in Appendix F show Oscillating dryer temperature may explain why dryer RVCM is highly variable between each activator cycle. There are many differences between Aberdeen's rotary dryers. Dryer 4 seems to contaminate resin more rapidly than the other dryers and therefore cannot be used for 5305. Dryer 6 is the slowest dryer in Aberdeen. Often dryer 6 runs with somewhat higher moistures than the other dryers. This is probably because operators try to push as much resin through the dryer as possible to keep up with production. During the February test run, a correlation between dryer resin moistures and RVCM was revealed. Dryer resin had less RVCM than moist resin. This is not a surprise, since water removal and VCM removal in the dryers follow the same The attached figures in Appendix F help illustrate the dryer controls situation. ih. .rfc, TT #1, I ... L&.'| " 1-r VAB.0001097526 A H. Silo Operation Improvaments Silos need to always be aerated properly in order to make 250 ppb 5305. Most of the operational problems which result in high RVCM happen at the silos. There is potential RVCM improvement by improving silo operations. Suggested operating improvements are listed below. 1. Automatic air flow control is needed at the silos. This can be achieved by installing a 1" bypass line around the silo air control valve (identical to the set up on silos 678--680, and 682) The yard operators need to be aware of what these lines are for. 2 Silo aeration valve indication is needed in the control room so that the dryer operator can tell if the air is on. Currently, practically none of the lights on the air valve on the dryer control panel are operable. 3. In order to ensure adequate 24 hour aeration, yard operators must unload the silos properly. When a silo is unloaded into a railcar, that silo needs to be completely empty before the railcar is topped off with another silo. 4. Improved communication between the dryer panel operator and the yard operator is needed. The yard operator needs to call the dryer panel operator to turn the air on or off when unloading a silo. After the yard operator is through, he needs to inform the dryer panel operator so that the air valve can be turn back on or off. Complete operating instructions are attached appendix G. I. Silo Aeration Improvements Silo aeration can be improved in a number of ways including: 1. Silo Air Pressure Control 2. Improved Air Distribution among the silos 3. Improved Air Distribution in the silos The items above are ranked in order of best effect on silo RVCM removal. Silo air pressure control valve would keep a constant air pressure out to the silos. Keeping a constant silo air pressure helps ensure that every silo gets adequately aerated. 1.1.| iinTn -- p 'iif' i pmunufru *'**"' VAB.0001097527 Currently, there is a problem with air distribution among the 5305 silos. The silos which are the farthest down on the air header (silos 678, 679, and 680) do not get as much air flow as the silos farthest upstream on the header (683 & 684). Consequently, silos 683 and 684 remove RVCM better than silos 678, 679 and 680. All silos experience severe air channeling during aeration. The center of the silo aerates much more than the outer edges or the cone. Improved air distribution would give a more uniform RVCM resin. Appendix G further contains some charts which further illustrate the silo aeration problems. J. Bench Scale Silo Silo aeration currently is highly variable. Large pressure swings on the air header cause silo air flows to fluctuate widely. Because of this, it is practically impossible to conduct aeration tests in the plant. In 1986, R&D built a small bench scale silo to test aeration on old technology 5265. It is felt that a similar apparatus would be helpful in determining optimum air flow rates and temperatures for 5305 RVCM removal. Results of the bench scale studies in 1986 are attached in Appendix C. During the move to Austin, R&D dismantled the silo and threw most of it away. However, according to R&D would be very inexpensive to build another bench model. it K. Reactor Stripping In early November, it was decided to try to improve reactor stripping for 5305 in an effort to reduce product RVCM. To do this, a system was set up that would open the condenser cooling water valve 10% when a) the reactor was in the recovery mode, and b) the slurry temperature was at least 175F. By supplying some cooling during stripping, steam flow through the slurry would increase, resulting in lower reactor dump RVCM. A similar manual setup was tested on reactor D-744 with 5415. The results of that test showed a 42% reduction in slurry RVCM to 68 ppm. Testing lasted two months, and condenser fouling on D-744 was comparable to the other reactors. A JU.' ra (Flti'TUi l< Jli-r liv i"lr-i' :a>L-4i4*r rJ H'. .'+! H *m*mmawm** r . uipjopm*--wnn VAB.0001097528 A An automatic system was setup for reactors D-700 and D-745 in mid November, 1989. 5305 reactor residuals were reduced by 50% in late November through January 1990. 5305 reactor RVCM was reduced from 185 ppm to 92 ppm. The improved stripping procedure also significantly reduced slurry RVCM. Appendix H has some figures that better illustrate the RVCM improvement during the test. During the test, product quality was closely monitored. No resin quality deterioration was found during the test. Resin b-color did not change, and contamination was low. L. Nested Experimental Designs A nested attempts to assign a percent of the total variability of a process to different areas. The area with the highest of the total variability would be the area worked on the improve. The actual percentage is not as important as the relative value in comparison to the other Two nested designs were completed in January. Both designs determined the percent variability due to the process, sampling and testing. Process variability refers to the actual variability in the process including equipment and operating variation. Sampling refers to the variation between samples and from sampler to sampler. Testing includes variation of the lab test and its technicians. In order to nest a process, samples are taken in '`layers". Each time a data point is needed, the sampler takes two samples. Each of these samples is divided so that each sample is tested in the lab twice. This forms three "layers" of which the variabilities are calculated. Figure 1 shown below further illustrates this layering. Figure 1 Nested Design Layers Sample o o o Wi|ani^..l4l '..l -lit -ITJ'k I- -li oo oo 18 oo oo n*lP IMaH1 VAB.0001097529 1. Blend Tank Nesting Based on the blend tank nested design it was determined that the process must be improved before the test and sampling method are improved. The blend tanks were nested to discover the process, sampling, and testing variability. Two blend tank samples were taken and these samples were split into two. Four data points are obtain per sample so that the three layers can be formed. Eleven sets of blend tanks were sampled for this nesting design. The sets of two were divided into individual tanks for evaluation. The twelve hour aeration average RVCM for both modules was 1.54 ppm for all the tanks. Old module blend tanks averaged 2.16 ppm while the new module averaged 0.8 ppm. Listed below in Table IV are the assigned percent variations due to the process, sampling, and testing. Average RVCM and overall standard deviations are also included in Table IV Table IV Blend Tank Nested Design % Variance - Process % Variance - Sampling % Variance * Testing Average RVCM, ppm Standard Deviation Overa11 66.9 13.9 19.2 1.54 1.04 Old Module 35.4 28.7 35.9 2.16 0.97 New Module 71.3 5.6 23.1 0.80 0.51 In the overall and new module cases the process is the best area to concentrate the efforts to improve. The old module percentages are practically equal, therefore, process concerns are as important as the other two areas. The process area becomes a larger contributor to the total variance as the RVCM value falls. The importance of the process is therefore magnified. The process should be improved first. There is a definite difference between old and new module blend tanks. The differences are probably caused by variations in the new reactor stripping procedures discussed a^lier in this report. During the nesting experiment, the improved reactor stripping system was operating on D-745, but not on D-700. The detailed results of the blend tank nested experimental design are included in Appendix I. l' - " n. --* !. 'H^ 1||.1 I H-r ir ^ C.-vl-- .!<' h" ' ns ih t- VAB.0001097530 2. Silo Nestling Based on the silo nested design, the process needs to be improved before the lab testing and sampling methods are improved. The silos were nested to discover the process, sampling, and testing variability. Two silo samples were taken and the samples were split into two. Four data points are obtained per sample taken so that the three layers can be evaluated. Ten silos were chosen for the nested design data. The silos were sampled from the top. The average RVCM value was 0.37 ppm. Listed below in Table V are the assigned percent variations due to the process, sampling, and lab testing. Also included in Table V is the average RVCM value, and the overall standard deviation. Table V silo Nested Design Item % Variance - Process % Variance - Sampling % Variance - Test Percent 86.6 1.8 11.6 Average RVCM, ppm Standard Deviation 0.37 0.30 The percent variance in the process is the obvious area to concentrate efforts to improve. This data verifies past lab studies which showed testing to be only 10% of the overall variability of dried resin samples. The detailed results of the silo nested experimental design are included in Appendix I. V. Summary This report is the culmination of four months of intensive test run work at Aberdeen in an effort to reduce RVCM. The recommendations presented in this report should allow Vista to produce 5305 resin with less than 250 ppb consistently. To get to the long term target of 10 ppb RVCM, Vista will probably have to make some fundamental changes in the way it produces FVC. An experimental design for recipe optimization and a potential future external steam stripping columns are some fundamental changes that may contribute towards the long A VaH-Hiffr -niN -win-..- *44*'*' '4* m 4. J VAB.0001097531 APPENDICES # * * 4 \ * i VAB.0001097532 Riant Air Survty t * I * \ ! i i i i i i i i ! i VAB.0001097533 A Appendix A Plant Wet Air Survey 21 I mM VAB.0001097534 At i -I Interoffice Communication FROM: DATE: Rich Tebo January 8, 1990 SUBJECT: Plant Wet Air Survey Attached is a detailed account of wet air users at Aberdeen. The wet air is supplied by the East Joy centrifugal and Joy reciprocating compressors. These two compressors send air to 1) all the blend tanks, 2) all the dryer activators, and 3) all the 600 series silos. Conclusions Wet air supply is insufficient to adequately supply all the users. Because of the limited air supply, air flow rates are well below recommended levels for proper blend tank and silo aeration. The recommended air flows are based on the RQIP design basis and are needed to a) adequately agitate the blend tanks, and b) adequately strip RVCM from the resin in the blend tanks and silos. Recommendations A. Short Term ft Two additional reciprocating compressors should be started up to supply additional air to the silos and blend tanks. B. Long Term increasing plant air capacity. include: These alternatives may 1. Installing a low pressure air system to supply air to the silos and/or blend tanks, 2. Optimizing aeration demands at a level below what was recommended by RQIP, 3. Installing mechanical agitation on blend tanks, 4. Installing a dilute phase V-ll dryer transfer system, or 5. Installing additional air compressors. a- fi HH< I im --n -Tin WMI |H1 ' fcW I*1P P VAB.0001097535 A The attached survey shows that Aberdeen's air supply to the silos and blend tanks is well below what is needed. Also, with the start-up of Low Mole Expansion , air demand will further increase (by over 500 SCFM). Additional air compressors need to be started up until a long term solution can be implemented. t"*- Rich Tebo Process Engineer Engineering Department Attachments cc: RWS \ PJK \ RBN \ CJMc \ SCH \ RDM \ PCS \ KWB \ DAMo File ABD.0.900108.1 1 T VAB.0001097536 A ABERDEEN WET AIR SURVEY The attached tables show how wet plant air is being used and supplied in Aberdeen. The basis for these tables is as follows: Silos 1. Each 5305 or 5265 silo should consume 375 to 400 SCFM for 40 hours while it is filling and aerating (based on work done by LZK and RJL in 1986). 2. During a 5305 run, up to 7 silos can be aerating at once. Five of the silos will be for 5305, one for 5265, and one for 5305 start-up. 3. The empty 5305 silos use 50 SCFM. 4. All the other silos use 50 SCFM when the silos are being unloaded in order to keep the resin fluidized. 5. When Low Mole Expansion starts up, the process will change such that three rotary dryers will dry 5305 to one silo. 6. One 5265 silo will be held for trucks when 5305 is run in the extra large reactors. 7. A separate silo will be used for 5305/5265 start-up in order to minimize debox. This silo will need to be Blend Tanks 1. The existing blend tank restriction orifices are designed for 75 SCFM air flow per tank. 2. RQIP recommended air superficial velocity for adequate agitation is 1.3 ft/min (SCFM/sq ft). RQIP recommends 1.3 ft/min for T-407 and 1 ft/min for the small tanks. This translates to 105 SCFM for the small tanks and 330 to 375 SCFM for the large tanks. 3. Blend tanks T-654, 655, and the V-10 blend tanks will not need any further increase in agitation. Air flow to these tanks will remain at 75 SCFM. 'H -M t- "UIIUIUl h-it.-aar- tw iiwuwi imui* mtmnm m VAB.0001097537  r A 1. The five activators in the V-ll dryer building use 458 SCFM when transferring. The V-ll dryer acitvator's have a transfer frequency of 3.71 minutes in a 5.54 minute cycle. Assuming that the transfer frequency and air rates are the same for all five activators and transfer at a random binomial distribution gives the results listed in the table below. Table I Activator Frequency of Occurence Plant Wet Air Survey Number of Activators Transferrina Simultaneously 1 2 3 4 5 Frequency of Occurance. % 4.4 16.2 32.8 33.1 13.5 Air Usage SCFM 458 916 1374 1832 2290 Most frequently, four activators are transferring at one time using 1832 SCFM. This is the listed average rate. Maximum air demand is five activators transferring which happens 13.5% of the time. This information was supplied by V.L. Thornhill in a telephone conversation in February 1988. -Jwi (t-t-nHWPIIpilNItp* I*1 in am, r*f(*l]W-'VHn4'4*rr * Mlf *W imp * VAB.0001097538 . - * i> A PLANT PROCESS AIR SURVEY East (Wet) Air System Users Silos iTIM+ 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 Total <----------Air Usage (SCFM)-----------> Actual Recommend LMW Exp 0 50 50 50 50 50 0 00 50 50 50 80 375 375 80 375 375 0 00 110 375 375 110 375 375 110 375 375 0 0 375 0 0 50 110 375 375 0 00 110 375 375 50 50 50 50 50 50 910 2875 3300 12/89 Estimated Air Flow Rate Targeted Recommended Flow Rate LMW Expansion Absolute Maximum 910 2875 3300 rifrinTiirnN'iimqirtp irti f miff iI.iiiL* >*!> VAB.0001097539 'nH-vNk A * Tm* Activator Usage Activator 4 5 6 7 8 Total Avg SCFM Consumed 366 366 366 368 366 1832 Blend Tank Usage < SCFM Consumed > Blend Tank Actual Recommend LMW Exp T-646 60 105 105 T-647 60 105 105 T-648 60 105 105 T-649 60 105 105 T-650 60 105 105 T-651 60 105 105 T-652 60 105 105 T-653 60 105 105 T-654 50 50 50 T-655 50 50 50 T"40/ 220 T-S01 220 oon OA ou T-747 220 375 375 T-502 220 375 375 4 Pond Resin Tanks 200 200 200 i.i'jnWPi* New Low Mole Silo ____0 ____0 105 Total 1660 2550 2655 VAB.0001097540 A -p- Total Usage SCFM User Normal Recommend LMW Exp Silos 910 2875 3300 Activators 1832 1832 1832 Blend Tanks 1660 2550 2655 Total 4402 7257 7787 ttnrrr^-w Air Supply Source Normal Max East Joy 3600 3600 Joy Recip 500 500 Ingersoll Rand Recip #1 0 500 Ingersoll Rand Recip #2 0 500 Innersofl Rand Recip #3 n vr aturru Ingersoll Rand Recip #4 0 450 North Joy (emergency generator) 0 500 South Joy (emergency generator) 0 500 Total'"U| 4100 7000 VAB.0001097541 4 Ptrticli Sizt 1 * VAB.0001097542 A Appendix B Resin Particle Size and Effect on 5305 RVCM VAB.0001097543 ... 4 t I" H r:jji.i r I rffc Vl 4WMU4 nw H Ml( p p m RVCM 5305 Dryer RVCM Distribution 5 4.7 RVCM vs Particle Size Mesh Cuts 7 "71 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 S S / / S / A/ y / A / S s // / // / / s / / ! / /' y s / y yl 60 2.5 y^-~r V/ r / y/ * / y Z' A / Af A yy V/ / A \ A V A/ / / v // / Yii- i/ Y/ A X v As / A y j YJ A A / _-f / T y s 80 1.4 100 120 0.4 T~ y/ y yA S r / 140 Mesh Size 200 Pan 1.11 Composite VAB.0001097544 -+M inm iihibmmi'P'wi i mmii i^--ii uppuw rfru^-t^uhn Ir HP WMWWIM^wpnp rtl+FtH,,L T 1<1 I * I f 1.4 1.3 1.2 1.1 1 0.9 I* ' 1^ ll ll Wi -'jp- > wr m: w, WP Ull II In Hi-* i lir 11 i 140 micron -- 1 ppm i 1.50 R elative D ryer RVCM (p p m ) 0.3 *MviW r*: Ht^PM Average Particle Size (micron) VAB.0001097545 2*> r i jjl(f r -srsi'-- 5305 RVCM APS Relationship p p m RVCM Ufl W VAB.0001097546 2* 5305 Particle Size Effects on Railcar RVCM 0.7 p p m RVCM 'lillFftH IP l Illlllill HMHipil mil hinaw Average Particle July--August 1989 V VAB.0001097547 W 4l nw- .il.) . r-. |H i.....................- . * F- " P -1 -J'l r"i JJT-.H- i MU' *fpr . U pH- .s^p if-V || i Wn | 5305 RVCM vs 60/80 Mesh February 1990 p p m RVCM to ftHMhH VAB.0001097548 hI P 4- ** '* 4* '< H J Him # m*' " II lll--wmi M i umiPniLLLi. Mr tt. h 11 5305 CPA Distribution Based on Particle Size 24% CPA 21% 20% 19% 18% 17% 16% 15% 60 M i in i Composite TI 80 100 120 Mesh Size -iHm niIPWWWTtii^P^*'W-NLW|MIWWpwwnW 140 ^ST 200 Pan VAB.0001097549 3* ' -if *+ 11 r ! 114 L <W APS (m icron) 190 180 170 160 150 140 dr 130 120 I 110 -j I- 100 90 80 T i 5305 Average Particle Size February 1990 // > 1 ITTTTT TT TTT Dryer Regular 'HI- H 1TT VAB.0001097550 APS (m icron) t*, m- f dL Wtt 5305 Average Particle Size January 1990 190 -|--------------------------------------------------------------------------------------------------------------------------- 180 - Ih-FtAI ' '-H W -* i|PMI(k |C4 r ihh 4 "Ml l--H k<|l ' J- T l '* *"-- **H- 4-.w'# |tJ t+r " flfl- IW*H ^rtpei r> *t-n\ iqiiiihup WHWHWRMtt MEAN PARTICLE SIZE LARGE RX DEC '89 & JAN '90 200 i------------------------------------------------------------------------------ M+ * MICRON 'df- -kT .1 1 l*H 64094 64439 64623 64819 84370 LOT# 84572 84713 tr~r* PKHMUPMHf *f*ipM?m***'H t. H VAB.0001097552 -T r>i ir- h* TT' -f M - jw-m xiqm jnt' rmil- ' It;*- mm* Particle Size Correlation n"-< CoV H - htrvn. HiniHiim L| Wl Mfl|W|W.................... Jill--Hi t* VAB.0001097553 * 1 - I It -t i- < Jl-h r- *|. iik-r-i iMln<B I If4inni|u IT IW'H'S IHT'<(| Tf CoV 0.62 0.6 0.58 0.56 0.54 0.52 0.5 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 80 5305 Particle Size Correlation APS vs CoV LJ n T i 7 ~T~ 100 120 nn n rLPin n n 140 160 180 APS :IH 'i#. UltalklkUfMlWW 'UfMtou>7k rrrr~~r rmim~ inr n iiiiM^ iin iMrtmiiwU................. ..... -fl ' l"i InirwffTipDiimi M. PPJPIIM iriNMip .......... C] VAB.0001097554 mw * ppm RVCM 5305 Shioment RVCM I 1988-89 o. 0.6 l 0.5 0.4 UCLx 0.3 0.2 e B Avg 0.1 B--B 0 Jon--88 TT Apr-88 T JuI-88 rTT Oct-88 Jon--89 J------ Apr--89 1" T Jul-89 LCLx T Oct-89 T Jan--90 VAB.0001097555 I ii -l- * H. IT* (si ' + * -rfi n |K^k.(tQ 5305 SHIPMENT RVCM January to March 1988 PPM RVCM 10 20 30 40 50 60 70 80 90 100 110 120 130 528 Data Points UCL = 0.46 ppm Sample Avg = 0.23 ppm im4fr iijijmm *w\m --mii**.llM HMWp rtf I- ^44t>- t m.PBI I'liMi I i.ini 4IMH VAB.0001097556 * tiTffjM- -we -T4*W --Vf tfW'W #fl*+'"<<qs-K pi i8iM(t | ^h='i> giaaiBjqf'* tm**i9+\ i ii Mm*. fimna^hul i 4 5305 SHIPMENT RVCM Range Chart Jan-Mar 1988 1.7 |------------------------------------- H---------------------------------------------------- ---------- 1.6 - PPM RVCM 10 20 30 40 50 60 70 80 90 100 110 120 130 528 Data Points UCL = 0.74 ppm Sample Avg = 0 32 ppm > *WS V4HW MM* * I 11 fci. I VMM tm/rmm VAB.0001097557 -.r, H' * H- -Ik 1 > Tl(. f -t*' f rfJi^ . .nj Vff' ^ > !# I-V'kd C- "+:*fi -r^.- 5305 SHIPMENT RVCM April to June -- 1988 PPM RVCM i *.tllfe| 0 10 20 30 40 50 60 70 80 90 100 110 120 130 528 Data Points UCL == 0.44 ppm Sample Avg =: 0.22 ppm I* il i i -nmimipi J* I im n< iwiiwriHPiwiinipi * VAB.0001097558 PPM RVCM 5305 SHIPMENT RVCM Range Chart April --June 1988 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 UCL 0.5 0.4 0.3 0.2 0.1 0 0 Avg f [ ' l ' 1 i i i i i" | i r m I I H I | I I II J I I T I | | | m | M | | 10 20 30 40 50 60 70 80 90 100 110 120 130 528 Data Points UCL 0.70 ppm Sample Avg 0.31 ppm VAB.0001097559 S* ppm RVCM 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 TTTTTTT1 i 5305 Railcar Residual VCM October 1989 Railcar Compartment UCLx Avg LCLx VAB.0001097560 2* 5305 Railcar Residual VCM November 1989 1.5 -------------------------------------------------------------------------1.4 1.3 1.2 - 1.1 - 10.9 -- 0.8 - 0.7 0.6 0.5 - UCLx ppm RVCM LCLx 1 * I I M m I I I i I I I I I i I I I I I I I i I I I I I | | II II I i I I II M II M I I I I I Railcar Compartment VAB.0001097561 2* q January 1990 RVCM Test Run ppm RVCM 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 l h Ji UCLx Railcar Compartment LCLx VAB.0001097562 Heated Silo Air VAB. OOO1097563 Appendix C Heated Silo Air VAB.0001097564 Experimental Design Table 2*3 Desicrns How ]Many Repititions? What is factor A? What is factor B? What is factor C? --> ==> ==> ==> 3 Aeration Time Hot Silo Aeration Isonox Kill Amount Is the effect of Aeration Time significant? Is the effect of Hot Silo Aeration significant? Is the effect of Isonox Kill Amount significant? Is the combined effect of A & B significant? Is the combined effect of A & C significant? Is the combined effect of B & C significant? Is the combined effect of A,B & C significant? Is the Aeration Time variability significant? Is the Hot Silo Aeration variability significant? Is the Isonox Kill Amount variability significant? Repitition Run 1 2 3 4 5 6 7 8 1 0.636 0.527 0.328 0.179 0.450 0.354 0.362 0.310 2 0.629 0.590 0.290 0.165 0.390 0.316 0.354 0.272 RAW DATA TABLE 34 0.836 0.722 0.550 0.469 1.111 0.960 0.710 0.588 5 VAB.0001097565 Run 1 2 3 4 5 6 7 8 Mean + + + + + + + + A -- + -- + -- + -- + BC AB AC BC ABC -- --+ + +-- -- ---- -- ++ + ---- + --+ + --+ -- ---- -- ++ -- --+ -- +-- + ---- + +-- -- +- + ++ + ++ Run 1 2 3 4 5 6 7 8 Sum+ SumOverall Difference Effect F Mean 0.70 0.61 0.39 0.27 0.65 0.54 0.48 0.39 4.03 0.00 4.03 4.03 1.01 Deviation MSFE d2 V v-num/dem Table F Table t 0.222 0.19 1.693 16 8 3.44 2.12 A -0.70 0.61 -0.39 0.27 -0.65 0.54 -0.48 0.39 1.82 2.22 4.03 -0.40 -0.20 1.49 B -0.70 -0.61 0.39 0.27 -0.65 -0.54 0.48 0.39 1.53 2.51 4.03 -0.98 -0.49 2.70 C -0.70 -0.61 -0.39 -0.27 0.65 0.54 0.48 0.39 2.06 1.97 4.03 0.09 0.04 1.09 AB 0.70 -0.61 -0.39 0.27 0.65 -0.54 -0.48 0.39 2.01 2.02 4.03 -0.01 -0.00 1.01 AC 0.70 -0.61 0.39 -0.27 -0.65 0.54 -0.48 0.39 2.02 2.01 4.03 0.01 0.01 1.01 BC 0.70 0.61 -0.39 -0.27 -0.65 -0.54 0.48 0.39 2.18 1.85 4.03 0.32 0.16 1.38 ABC -0.70 0.61 0.39 -0.27 0.65 -0.54 -0.48 0.39 2.04 1.99 4.03 0.05 0.03 1.05 i- VAB.0001097566 l To: R. B. Quy, R&D, Ponca City Interoffice Communication From: Date: Subject: R. J. Lahiere, Polymers Research June 11, 1987 ENHANCED RVCM REDUCTION WITH HEATED RESIN IN BENCH SILO Previous work with the bench-scale silo indicated that resin temperature influences the extent of RVCM removal from resin with aeration. Temperature effects are an important aspect of silo aeration because RVCM transfer rates have decreased during cold weather operation in the past. This investigation confirmed that the RVCM transfer efficiency from resin during silo aeration is increased at higher resin temperatures. The temperature of the resin used in the silo was adjusted by drying the resin in a fluid bed drier, thus heating it to about 130F. Silo aeration experiments employing heated resin were compared to previous work in which resin initially at ambient temperature was used. Conclusions of the study are discussed in greater detail below. Steps should be taken to warm silo resin during winter conditions to prevent the reduction of RVCM removal. The resin can be warmed by (1) heating the aeration air and (2) improving air distribution in the silos with more efficient sparger designs. More RVCM Removal in Heated Resin Aerated With Ambient and Hot Air Silo aeration with air at 7TF and 150F removed more RVCM from resin when the initial resin temperature was 130F, rather than 77F. This effect is shown in Figures 1 and 2. The average temperature during the run of the heated resin was greater than that of the ambient-temperature resin. Since the heated resin stayed warmer, the diffusion of vinyl chloride out of the resin particle was increased. This diffusion mechanism is the rate-controlling step of the mass transfer process in the silo; higher diffusion rates resulted in more RVCM removed from PVC. Less RVCM Removal in Heated Resin Aerated With Cold Air Less RVCM was transferred from heated resin than from resin at ambient temperature when the silo was aerated with 40F air, as Figure 3 shows. When heated resin was aerated, the silo was wrapped in insulation and a cooler average resin temperature was maintained with the cold aeration air. The resin tempera ture averaged about 46F during the latter part of the experiment with hot resin and an insulated silo compared to 64F for the run with ambient-temperature resin and a silo without insulation. Lower resin temperatures in the heated-resin experiment reduced the amount of RVCM removed. VAB.0001097567 R. B. Quy Page 2 June 11, 1987 attachments cc/attachments: Ponca City: SEM CJMc AWW MEO WCT RRH JLC Aberdeen: DWH VEM FGJ Houston: LZK JFN Oklahoma City: JDO RP Saddlebrook: RDJ VAB.0001097568 i 77 F Air, 0.95 scfm Flow Rate RVCM Remaining in Resin (%) Init Res Temp, 77 F Aeration Time (hours) + init Res Temp,130 F 4 I VAB.0001097569 RVCM Remaining in Resin (%) Figure 2 Effect of Init Resin Temp in Bench--Silo 150 F Air, 0.38 scfm Flow Rate VAB.0001097570 RVCM Remaining in Resin (%) Figure 3 Effect of Init Resin Temp in Bench-Silo 40 F Air, 1.90 scfm Flow Rate VAB.0001097571 5305 RVCM Removal in Silos November 1989 Test Run A p p m RVCM ppm RVCM 5305 RVCM Removal in Silos November 1989 Test Run VAB.0001097572 Heated Blend Tanks fr VAB.0001097573 Appendix D Heated Blend Tanks VAB.0001097574 2/2 FACTORIAL DESIGN PROJECT TITLE m Small Blend Tank RVCM Removal DATE: Janurary 25, 1990 RUN# 1 2 3 4 + + + MEAN 1.09 0.40 0.62 0.39 + + A 1.09 0.40 0.62 0.39 - + + B 1.09 0.40 0.62 0.39 + + AB 1.09 0.40 0.62 0.39 Y-BAR 1.09 0.40 0.62 0.39 R 0.73 0.42 0.53 0.29 SUM+ SUMOVERALL DIFFERENCE EFFECT STD. DEV. T-VALUE* 2.12 2.50 0.00 2.50 2.50 0.62 0.21 0.78 1.71 2.50 -0.93 -0.46 MSFE F-VALUE* 3.44 1.01 1.49 2.50 -0.48 -0.24 0.20 1.48 1.02 2.50 0.47 0.23 d2= 2.326 IS THE EFFECT OF A (Steam Injection) SIGNIFICANT? YES IS THE EFFECT OF B (Hot Water Rinse) SIGNIFICANT? YES IS THE EFFECT OF A (Steam Injection) & B (Hot Water Rinse) SIGNIFICANT? YES IS THE VARIABILITY OF A (Steam Injection) SIGNIFICANT? NO IS THE VARIABILITY OF B (Hot Water Rinse) SIGNIFICANT? NO IS THE VARIABILITY OF A (Steam Injection) & B (Hot Water Rinse) SIGNIFICANT? NO REP # RUN 1 RUN 2 RUN 3 RUN 4 CENTER PTS 1 1.48 0.62 0.74 0.24 0.00 RAW DATA 23 1.43. 0.49 0.89 0.23 0.00 0.95 0.45 0.55 0.52 0.00 4 0.86 0.22 0.36 0.45 0.00 5 0.75 0.20 0.56 0.50 0.00 VAB.0001097575 fr fc * J * tN t - November 1989 Test Run ppm RVCM VAB.0001097576 ppm RVCM m 5305 Sma Blend Tank RVCM Remova Steam Heated to 150 F M VAB.0001097577 >> 10 -f] 5305 Blend Tank RVCM Remova November 1989 Test Run ppm RVCM Aeration Time * VAB.0001097578 PC 4h*p>l pin- 'i ^-qvipjhP'kF#1 ' rf-l'a Htrfu-H* t' rf J,` t ......... ^*<4llf' N nil|HippiiPr 11 fPfn iin wiiviirmiH'ff it *\\' MiPiftiiiimi m* pmmpni+p^>wn^| ON* 5305 Blend Tank RVCM Remova Blend Tanks Steam Heated 10 9 8 7 6 p p m RVCM 5 4 3 2 1 0 0 2 4 6 8 10 12 14 Hours Aeration y = aexp(bx) VAB.0001097579 > \ co /a 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 T * _|jT i J1ii -144 -_1jpi i! r J ii f H H h i*H r\ i1 *T*iit 0 A Water R'v'CM Stripping 1SLM0 Taa/JC Water end 5305 Slurry . j. 4 \ X 1 30F Slurry !* i i i i ii i <j * i j tii j + i 1| 111 1 jt f j * ti i p RVCW Stripping Water and 5305 Slurry 4 0.01 0.001 0.0001 0.00001 0.000001 A Water X 130F Slurry Hours Aeration V 150F Slurry `1------T 12 VAB.0001097581 Co/Ci RVCM Stripping Water and 5305 Slurry 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 4- 0 2 4 A Water x 130F Slurry 6 8 10 Hours Aeration v 150F Slurry ~1 T 12 14 VAB.0001097582 RVCM Stripping Water and 5305 Slurry 0.02 Hi J n td j i ( i A Water X 130F Slurry v 150F Slurry VAB.0001097583 RVCM Stripping / / i r / /T C o /C l A Water X 130F Slurry Hours Aeration v 150F Slurry VAB.00010^7584 * ti ll K* 5305 Blend Tank RVCM Remova Blend Tanks Steam Heated Ln(C /C i) Hours Aeration VAB.0001097585 i mi 4 5305 Blend Tank RVCM Rem ova Blend Tanks Steam Heated 4 d p p m RVCM Hours Aeration y=ae~((lnx -- b)~2/c) N(\ - FclC*/o- blf'tvlK/t VAB.0001097586 ppm RVCM 5305 Small Blend Tanks Pumpover RVCM 12 hours Aeration 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 Small Blend Tank D n=4 VAB.0001097587 ppm RVCM 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 5305 Small Blend Tanks Pumpover RVCM vs Time 10 February 1990 Time during Pumpover + General Time Avg VAB1)001097588 Agitation VAB.0001097589 Appendix E Blend Tank Aeration/Agitation VAB.0001097590 5305 Large Blend Tank RVCM ppm RVCM Time VAB.0001097591 5305 Sma end Tank RVCM 1 2 Hour Aeration Low Air Flow p p m RVCM Blend Tank Air approx 50 SCFM VAB.0001097592 > Sma end Tank RVCM 12 Hour Aeration High Air Flow p p m RVCM Blend Tank Air approx 75 SCFM VAB.0001097593 Dryer Controls VAB.0001097594 Appendix F Dryer Controls VAB.0001097595 ppm RVCM 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 -m 0.2 0.1 0.0 i T Jan--88 Monthly 5305 Dryer RVCM 1988-89 S, \ \W \ vr \ hr to to to to TT Apr--88 T TT Jul-88 TT Oct-88 TTT Jan--89 TT Apr--89 TT Jul-89 TI Oct-89 1 UCLx m xar Avg LCLx I1 Jan--90 VAB.0001097596 >> i 5305 Dryer RVCM February 1990 3.2 i------------------------------------------------------------------------------------- ppm RVCM Dryer p VAB.0001097597 % RVCM Removed 5305 Dryer RVCM February 1990 100% -i----------------------------------------------------------------------------------------- Remova 20% 10% - rrn i i i i r n i i i i i n rrn i n 11 i i i i i n rrn i i r i i i i i n n i i i i i i rr i r i i m i i i i i i Sample VAB.0001097598 % eiV\IUA*TUAC tTtMp - cUoxir VAB.0001097599 CM tXip cUo^: < Ir VAB.0001097600 r. r U hr T L 2AiA 53S cn>OAAo. VAB.0001097601 I s I t I I i \ I i % p t i I 1 c 1: , 1 I I I VAB.0001097602 *% S30S MMMM MMI VAB.0001097603 *I Silo Aeration * VAB.0001097604 Appendix G Silo Aeration VAB.0001097605