Document vBZ68Dg2eQ1bnk5mp0nNVJvnE

2357 OxvTech PLAINTIFF'S EXHIBIT POIYRRMIX TM A DEPOSIXABLE REPLACEMENT FOR Asbestos diaphragms h . 'U Z I S t r Jr? OxyTech Systems, Inc. 470 Center Street Chardon, Ohio 44024 ST0512024 ST05I2025 POLYRAMIX*TM) A OBPOSITABLE REPLACEMENT FOR ASBESTOS DIAPHRAGMS BYS L. CALVERT CURLIN & THOMAS F. FLORKIEWICZ OXYTECH SYSTEMS, INC: AND: RUDOLF C. KATOUSEK ELTECH RESEARCH CORPORATION PRESENTED AT THE 1988 LONDON INTERNATIONAL CHLORINE SYMPOSIUM 1-3 JUNE 1988 ST0512025 A Peposltable Replacement for Asbestos Diaphragm By: L. C. Curiinj T. P. Florkiewicz, arid R. C. Matousek" INTRODUCTION . OxyTech Systems is a joint venture company formed between Occidental Chemical Company (formerly Hooker Chemical and Diamond Shamrock Chemical companies) and eltech systems to license# market and continue to improve upon the technology and rich heritage of the parent companies in the field of Chlor-Alkali Electrolysis. Hooker Chemical introduced the first deposited asbestos diaphragms in 1929, and Diamond Shamrock introduced the Modified Diaphragm) iTM) and Expandable AnodevTM) in the early 1970s. ELTECH Systems is a leader in the field of DSA'R) anodes. These technologies are used alone or together for over 70% of the world's chlorine production. In recent years, papers presented at symposiums, such at this one, focused on developments in the .field of membrane cell technology. It is recognized that most new grass roots chlorine plants will utilize membrane calls. We at OxyTech Systems are very active in this field having licensed twenty seven (27) membrane cell plants. However, OxyTech systems also has 151 diaphragm cell licensees producing more than eight million tons of chlorine per year. This paper for a change is about a new diaphragm cell technology. in North America alone diaphragm cells account for 76% of the chlorine capacity. Sixty percent of the diaphragm cell chlorine capacity is in plants having cogeneration of electricity and steam. The use of asbestos has become a concern for all producers of chlorine with diaphragm cells, as the use of asbestos may be banned. However even if it is not banned, asbestos may become too difficult to obtain, or too expensive, or it may become economically impossible to dispose of the asbestos waste. The record of the chlor-alkali industry in compliance with asbestos handling regulations is very good. Therefore, it is doubtful that the use of asbestos specifically in the chlorine industry will be banned. The other economic situations are at this time more of a factor. Thus, any alternative technology to replace asbestos diaphragm cells must stand on its own economically to be attractive to today's chlor-alkali industry. The present alternatives to the asbestos diaphragm cell are membrane cells or non-asbestos diaphragms. One would first consider conversion to membrane cells. However, PEI associates in a report to the U.S. Environmental Protection Agency has 1 ST05I2026 ST0512026 estimated that it would require a capital investment of two billion U.S. Dollars to convert the United States diaphragm cells to membrane cells1 Next one might consider-retrofit of membranes into existing diaphragm cells. This has already been accomplished in most of Japan's diaphragm cells. However, the conversion in Japan was accomplished with large government subsidies. All known studies in the remainder Of the world have concluded that the retrofit technology is uneconomical compared to continued operation of the existing diaphragm cells. ' For these reasons oxyTech set out to produce an economical replacement for asbestos in diaphragm cells. The result of this effort is called poLTRAMlX. ST05 I 2021 ST0512027 WHAT IS POLYRAMIX? The nan* POLYRAHIX is derivedfrom the words polymer end ceramic. POLYFAMIX, or as it is also called "PICOTM)", is a unique (patent pending) fibrous material produced from a physical combination of metal oxide particles and a fluorocarbon resin. The preferred metal oxide is zirconium oxide, although, other metal oxides such as titanium dioxide can be used, and the preferred polymer is PTFE, however, other fluorocarbons could be substituted. The PMX fibers are branched, irregular, and flexible with lengths of 1 to 7 mm, and diameters of 10 to 100 microns (figure 1). The metal oxide particles are not only dispersed throughout the fiber but also attached to the fiber (figure 2). The density is twice that of asbestos. Other non-asbestos diaphragms have been developed in the past. Fluorocarbons have been the most successful, OxyChem developed the "Microporus Diaphragm1' a sheet of PTFE containing sodium carbonate as a pore former. The difficulties of wetting the fluorocarbon were overcome, and the operating results were satisfactory, however, the product was manufactured in sheet form, and the labor required to apply the sheets to the cathode tubes, the relatively high cost of the PTFE, and the lack of commercial production technology, prevented its commercialization. The knowledge gained about vetting of the Microporous Diaphragm by OxyChem and the experience with conductive ceramics developed for aluminum cells of ELTECH, were significant factors in the successful development of POLYRAMIX. ST 0 5 I 2 0 2 8 3 ST0512028 APPLICATION OF POLYRAMIX The -tibrous and flexible nature of POLYRAMIX accounts for its......... advantage over previously developed non-asbestos diaphragms. POLYRAMIX is vacuum deposited on a diaphragm cell cathode from a vater based slurry in the same manner, using the same equipment, as an aebestos or modified asbestos diaphragm. In most cases only minor equipment changes would be required to convert an existing plant to use of POLYRAMIX. After deposition and vacuum drying, where drying vacuum in excess of 500 mm Kg is applied to produce a smooth tight diaphragm, the POLYRAMIX diaphragm is heat cured. The same oven and the same temperatures as used to cure an OxyTech SM-2 Modified Diaphragm are utilized. Since a hydrophobic fluorocarbon constitutes a portion of POLYRAMIX, the diaphragm is treated with a surfactant prior to assembly into the cell. This is accomplished by simply immersing the cathode in a tank filled with water and the wetting agent. The depositing system vacuum pump is used to thoroughly and evenly vet the diaphragm. Due to the prewetted condition of the POLYRAMIX diaphragm, which accelerates the even percolation of brine through the entire diaphragm, brine flow rates at start-up. are somewhat higher than for Modified Diaphragms. Within an hour, however, after start up, the surfactant is washed from the diaphragm and brine flow rates are set to achieve the desired caustic strength. The POLYRAMIX diaphragm does net require revetting after each circuit shutdown as long as the diaphragm remains covered by brine. 4 ST0512029 ST 05[2029 EKVIHONMEMTAL COHCERMS Since POLYRAMIX has been developed due to the problems with asbestos, one of the more commonly asked questions is; 'What about the health and environmental status of POLYRAMIX?" The comparison of asbestos and POLYRAMIX fibers is; m" CHRYSOTILE. ASBESTOS Fiber Diameter (microns) 10 - 100 Fiber Length (microns) 1000 - 7000 ( 0.1-3 0.1 - 60 POLYRAMIX is a much longer, coarser fiber than asbestos* Asbestos is carcinogenic due to its physical properties. The length and diameter fall within the range considered peak for carcinogenic potency. Figure 3.0 is an illustration of this, and the comparison to POLYRAMIX. Thus POLYRAMIX falls well outside the carcinogenic range. It has not been possible to conduct inhalation studies with POLYRAHIX as its size and density prevent its suspension in air. . The raw materials comprising POLYRAMIX (FTFX, Zr02, and NaCl) are also non-carcinogenic. Disposal of waste asbestos is now required to be conducted in approved toxic landfills, such treatment should not be required Of POLYRAMIX. co CO in PO o CO o s ST0512030 STATUS OF-PMX-WQSK -POLYRAMIX is now being deposited and -operated -on -commercial sized electrolytic diaphragm cells in actual commercial cellrooms. To this date polyramiX performance has been demonstrated in four different sized cells, at four different current densities, in four different oxychem plants.. Cell Type Cathode Area Current Density MDC-21 MDC-29 MDC-55 H-4 23m2 32m2 60m2 74m2 1.50 KA/m2 2.59 KA/m2 ' 2.20 KA/m2 2.32 KA/m2 A total of more than twenty-five POLYRAMIX cells are currently in operation. Development efforts have succeeded in steadily improving the performance levels of the diaphragms. Recent performance of POLYRAMIX diaphragm is presented in figure 4.0. The diaphragm age of the oldest commercial sized PMX cell is currently 570 days (19 months). Based upon the data from theoldest cell (figure 5.0) and laboratory experience OxyTech is confident that the life of an average POLYRAMIX diaphragm will exceed three years. An area of continued development work is in optimization of the ^ diaphragm weight. Because POLYRAMIX is more dense than asbestos, the resulting POLYRAMIX diaphragms are heavier if the total number of fibers is kept the same. The thickness is requirsd to obtain satisfactory current efficiency and anolyte level. The thickness, however, contributes to the voltage. As usual with diaphragm cells, we have been balancing the diaphragm weight to achieve optimum performance. Figure 6.0, illustrates, however, that we have been able to reduce the diaphragm loading and thus the voltage while maintaining anolyte level and good current efficiencies. At present the slope of voltage versus current density is somewhat higher than a standard SM-2VTM' polymer modified asbestos diaphragm for the commercial cells, although laboratory results indicate an equal slope. Thus at low (1.5 KA/m2) current densities the commercial POLYRAMIX cells demonstrate similar voltages to the modified asbestos cells, but at the higher current densities the POLYRAMIX cells have had slightly higher voltages. At all current densities, however, the current efficiencies of POLYRAMIX cells are equivalent to the efficiency of the standard cells. Laboratory work and now plant experience have demonstrated that POLYRAMIX diaphragms are significantly more resilient to current load fluctuations, power outages, and onpeak-offpeak operation than modified asbestos diaphragms. This can be explained by the resistance of POLYRAMIX to chemical attack. The magnesium 6 ST (1512 0 3 1 ST0512031 hydroxide in the asbestos is chemically attacked by acids and alkalis. During power outages or even current density changes the pH gradient across the diaphragm changes. In time the asbestos disintegrates and the current efficiency is reduced;POLYKAHIX is made of Teflon and Zirconium Oxide. These compounds are not affected by pH changes. This also accounts for the long life projections for POLYRAMIX diaphragms. POLYRAMIX-should be economical today for a plant operating with onpeak-offpeak power or frequent outages. POLYRAMIX diaphragms can be plugged with brine impurities just like modified asbestos diaphragms. However, POLYRAMIX*s ability to withstand pH changes without degradation of the diaphragm results in an added benefit, shutdown of POLYRAMIX cells often results in an improved current efficiency and a lower voltage as the impurities are washed from the diaphragm by the acidic brine. This does not mean that poor quality brine is satisfactory for PHX operation. The ppb hardness level required for membrane cells is not necessary, but less than 4 ppm calcium and less than 0.5 ppm magnesium is satisfactory. 7 ST0512032 S T O S IP -032 ECONOMICS -It is oxyTech's-opinion that a commercially successful non- ... asbestos diaphragm must economically compete with the modified asbestos diaphragm. Possible future governmental regulations and increasing public concern about the environment and toxic waste disposal will increase the cost of producing, transporting, and disposal of asbestos. As these costs increase, conversion to the use of a non-asbestos diaphragm such as POLYRAMIX will be economically justified. This will occur sometime in the future. The economics and timing of conversion to POLYRAMIX will be determined by the analysis by each individual chlorine plant of the following factors: - Cost of a POLYRAMIX diaphragm; - Life of a POLYRAMIX diaphragm and operational stability; - Power consumption; - Asbestos and asbestos related costs. As previously discussed, a POLYRAMIX diaphragm is approximately two times heavier than a polymer modified asbestos diaphragm. In addition, PTFE polymer and zirconium oxide .are more expensive on a per unit of weight basis than the present cost of asbestos. The combination of the greater diaphragm weight and the higher cost per unit of weight makes the present cost of a POLYRAMIX diaphragm approximately ten times higher than the present cost of a polymer modified asbestos diaphragm. The present cost of POLYRAMIX is twenty dollars per kilogram, however, because NaCl is used to keep the fibers from agglomerating, the effective cost is forty dollars per kilogram. Present optimization has resulted in a diaphragm weight of approximately five kilograms per square meter of cathode area. This results in a present cost of two hundred dollars per square meter of cathode area. The second factor to be considered is the life of the POLYRAMIX diaphragm. As mentioned earlier, the life of a POLYRAMIX diaphragm is projected to be at least 1000 days as compared to a polymer modified asbestos diaphragm life of approximately three hundred days. Since the life of a POLYRAMIX diaphragm is greater than three times longer and the other cell renewal costs such as labor are proportionally less, the effective cost of a POLYRAMIX diaphragm is reduced to approximately three times that of the polymer modified asbestos diaphragm. The cost of using asbestos today and in the future is very dependent upon the costs associated with handling and disposal of asbestos. The present conservative estimate of this cost is $0.50 per metric ton of chlorine. This cost includes depreciation on the fixed capital investment, insurance, special work clothes, asbestos recovery, waste asbestos packaging, and disposal at an approved landfill. ST0512033 s T0 5 1?-033 Taking the above four factors into account, the economics of POLYRAMIX versus present Modified Diaphragms is presented as figure J.O. Using the assumptions of a 5 Kg/m2 PMX diaphragm,.*, looo day PMX diaphragm life, and equivalent power consumption, the incremental operating cost of POLYRAMIX technology on an MDC-55 diaphragm cell is $1.33 per metric ton of chlorine more than present Modified Diaphragm Technology costs. .Analysis of various different plant economics has revealed that the range of increased operating costs under the present asbestos -cost situation is between $1.00 and $2.50 per metric ton of chlorine depending on cell type and current density. Future advances in POLYRAMIX technology or changes in the cost of mining, transporting, storing, and disposing of asbestos would shift the economics in POLYRAMIX's favor. For example, a three to four fold increase in asbestos related costs would make the economics equivalent. Such a cost increase scenario is reasonable considering the present concern with proposed regulations concerning the use and disposal of asbestos. 9 ST0512034 n e o z is u is rvms.ffqRK OxyTech has bean pleased with the progress in development of the POLYRAMIX technology in the economic replacement of asbestos. The POLYRAMIX development program continues to receive high priority and support of OxyTech's directors and parent companies. The present POLYRAMIX diaphragms operate with similar power consumption as polymer modified asbestos diaphragms. We believe that with further developmental work the power consumption of POLYRAMIX cells will be lower than conventional Modified Diaphragm cells today. t The next program objectives are: - Reduce power consumption to less than Modified Diaphragms; - Reduce POLYRAMIX manufacturing costs; - Demonstrate commercial POLYRAMIX performance in different i cells and plants. With modifications to depositing procedures, reduction in diaphragm weight appear achievable. The lower weight will reduce cell voltage and reduce the usage of PMX required and thus also the cost. Presently, POLYRAMIX is manufactured in a pilot plant facility. Projections are now being made on the manufacturing costs if a commercial sized production facility is constructed utilizing economies of scale including bulk purchasing and handling of the raw materials. OxyTech operates an independent POLYRAMIX depositing plant within the grounds of Occidental chemical's Battleground Texas plant. This facility can deposit cathodes of all known sizes. OxyTech is presently scheduling deposits of cathodes for several companies to demonstrate the performance of POLYRAMIX, and to give these companies experience with POLYRAMIX long before full plant conversion is contemplated or required. in summary oxyrech systems has developed a depositable replacement for asbestos in the chlor-alkali industry. POLYRAMIX and the materials it is manufactured from are non-carcinogenic. Existing diaphragm cell plants could convert to POLYRAMIX with minimum additional capital investment. POLYRAMIX is available today for in plant demonstrations. POLYRAMIX will be an attractive economic alternative to asbestos when the chlor-alkali industry requires one. 10 ST0512035 STD5I 2035 FIGURE 1 .0 Branch Chain Structure of PMX ----- -------- SM-54-2-Q-3&Q ST0512036 FIGURE 2 .0 Micrograph of PMX Fiber Showing Attached Metal Oxide Particles ST05 I 203-7 - ST0512037 o <n c 1-2 CO >o 5E o .2 CL O |cooc O) o o S3 cO M P 23 CO U" O co <0 CO <D < r-+s-* -Ow %O W0 >>JQ j= o< E d. co o o c oQ>) CB O ^.sa <3 E dL in CM CD O CD .<CSSD Q O I -c 0> c CD hJ (FIG . 3-0) Source: Figure 4.5 Pott (1980) ST0512038 FIGURE 4 .0 , Power Consumption - PMX vs. Polymer Modified Asbestos Diaphragm Power Consumption OCKWH/MT.CI2 ! rr&s-raws- 8 CO 0) CM Q O 5 cm s a 2 x: Q. co Q. ?o 2- * .g> 9O) G 2 in ^ co> c o >. CO G co io x z CQO Cell Liquor TO ST0512039 STGSTZtm* ' o s w_ eCD cm _ o :2 CMi cn 2 O m ^ Q..25 CO Q iq cq co - CfjQS <o CO Days on Line Oi io >o CO . 00 CO CO CO d *3 O LL c d> 3 o ST0512040 O o: -o > % STQ512041 PMX Cell Voltage vs. PMX Diaphragm Weight PMX Diaphragm Weight, Kg/M ST0512041 FIGURE 7 .0 PMX Economics Analysis of Operating Costs Operating Cost, $/MT.C!2 Life = 300 Days ------------------ --------------------------------------------------------^-------------- T- CM o o CO cq CO 05 CVJ LO CO 05 CVJ CO oo o o r-' CO Co 05' a ^ + to- 0 CO 0 uc 80 oX o 2Q CD CO CO o *^5 *CO* CO oCO CO < 5o6o S.0Q5SJDQO CO Ji oCoO 0c5 2 0 oCL a c 0 CO T"* oCO CoVJ CO o o te- CO CM CO te Cv_D o c tVn? CO ll CD CO 0 0 o0 c 0 0w5 0 0 -C O 05 c .2 O X E "D 00 0u0 o-C X Q. 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