Document 1J9rR4oJpXvnXabY7XJGJ0z5

Baseline In the past decades, dust collection from industrial processes has undergone extensive development `worldwide. Particle emissions not only from production processes of cement, steel or even food, but also from coal-fired bollers or waste incineration plants, have been reduced drastically by nstaling fier plants equipped with texte fier media. In the meantime, t has become common practice to oblige fiter media suppliers to provide warranties fo emission ims and for the Ifetime of installed iter media, especially in case of ho gas filration applications up to 250C continuous operation temperature. There i a volume of millons of sqm of ht gas filer media installed worldwide. The: annual consumption of PTFE products in filration applications in the EU s estimated at around 2500 4p to 3000t0ns base on reliable data available from the market (suppliers, customers, own production volume). "The statutory emission limits have dropped step by step; today they are often fixed at 10 or mgiN and for some installations customers request even lower emission imis. To guarantee a service Ife of 3 years or more at that low emission rates, not only a high level of expertise is required, but also very reliable material specifications and process management. Additionally raw materials of a high and well-known product quality are necessary. An overview about material used In hot gas flration applications up 0 250C continuous temperature is given in Table 1. Is worth noting thatthe figures `given are maximum values only possible in case of optimum conditions. That means harmful chemicals like water, acid or alkaline compounds or oxidizing agents Ike NO, are absent or present only at very ow levels. The only exception is PTFE as there is no riskof chemical deterioration by presenceofthe mentioned chemical compounds due to the outstanding chemical stabiofltthye fuoropolymer. The extraordinarily high binding eneorfgthye C-F-bond is the basis for the outstanding chemical and therm stabilty of PTFE that only consists of CF and CFgroups in the polymer chain. Table 1: Hot gas fitration media sFcibirmeaTynpdes Coonpternauiongus BEnWviProtec ReHsydirsoalynsciesloReAsciidssancelo ReAsliksaltsnTMcelo emp' Designation (Maximum) Palyphenyienesulfide_190C/200C) PPS color. _ecolert_exellnt mAramide 202200) NO modete moderte _modarste Polyimide 202800) PI 9d moderste moderate Polytetrafuorenyiene 250CI280C) PTFETFL excelent excelent excelent Fibreglassfabric __ 260C/285C) GL 00d modes moderste ReOxsiidastniocneto moderate moderate good excelent excelent 2 A defined group of polymer materials has been established for use in industrial dedusting at elevated temperatures, with PTFE being of particular importanacse a unique polymer due to its especially high chemical and thermal stability and the antiadhesive character. PTFE has proven in various layouts: high tenacity yam, staple fiber, aqueous dispersion, sewing thread and ePTFE-membrane being the most used. The use in shape ofa microporous sheet as an ePTFE-membrane is of very special interest as an extraordinarily high particle separation efficiency can be realized with an amount of only 2-5 gim of PTFE polymer. Inforomnaaltterniatoivens f one had to switch to other polymers such as PPS or PET due to a ban of PTFE, this will result in `extremely short lifetimes under the conditions of for example 210C, 1500 ppm NOX and 20% humidity, typical data for an alkali bypass filter in a cement plant. A very rapid chemical, and thermal `degradation (oxidation, hydrolysis) will take place. A warranty of safe operation for three years with emissions below 5 mg/m is therefore inconceivable; but ths kind of warranty is common practice. today and expected by the customer. Selecting from the groupof known and available polymer materials only PTFE is able to handle these process conditions over years and to fulfil the warranty requests. Alternative polymers would allow neither trouble-free operation nor sufficient lifetime. ff a relevant customer needs to opt for alternatives e.g., PPS (poly-phenylene-sulfide) the lifetime of the installed fier medium would go down to 2-3 months or even lower. In case PET (poly-ethyleneterephthalate) is chosen the resulting lifetime will be a few days only. If one tries to adjust the operating conditions 50 that PPS or PET are able to fui the task, the process gas needs to be cooled down significantly. This can be technically achieved with excessive feed of `ambient air or water spray injection. However, this either increases the gas volume, so that the filter system needs to be extended accordingly or the water dew point is raisedby the increased amount of moisture, which can make dust firation operation impossible at all due to water condensation. For example, if a gas volume flow with a temperature of 220C is cooled down to 120C with ambient ar, the gas flow increases by a factor of 1.6. `The plant conversion ifpossible, at the given location - will cause corresponding investment and `conversion costs. In addition, the energy and material consumption will increase, as the lifetime of the 3 subsiitutes will be much shorter compared to PTFE needle fel installed. For this reason,the amounotf waste created will rise accordingly. Since the dust contaminated fiter mediais usually waste that requires monitoring, special attention should be paid to this. If chemically and thermally less resistant substitute materials need to be used, the direct consequence would be asignificant reductionoflfetime of installed fiter bags- fit will work at all under the given process conditions. This would be accompanied by a risk of failure, resulting in significantly increased `emissions and thus a ising health risk for the population due to much higher- possibly toxic - fine dust particle emissions. `The need to replace substitute products with shorter ifetimes more frequently not only increases `consumption of resources, both in terms of raw materials and energy for production, transport, and waste removal. In addition, there is a larger waste stream with the associated expense for all necessary transport routes, the higher maintenance cost, and the disposal of a bigger volume of used fiter media. Thus, to go without PTFE in relevant applications will not result in any benefit, plus the. CO2-footprint wil rise significantly. What's more is an aspectofwaste disposal: When used fier bags are replaced, they are either mechanically or chemically degraded, but they are for sure covered and penetrated with any kind of dust. The waste disposal is defined by local authorities' guidelines, may be incineration, landfill or ~ in alot of cases - underground backfill. The user of the filer media is not enabled to decide himself, how to proceed, but a reduction of fiter media lifetime will for sure create a rising amount of waste to handle and to get rid of. Recyclingofused - and usually -contaminated and degraded fier bags with integrated metalic parts is not realized in mentionable amounts. Some very early phase discussions started, but this is a longterm process covering collection, identification and cleaning of used materials as well as defining legal `and commercial circumstancesof a recycling system including aspectsof safety in case of critical dust and handling of the cleaning residue. On the one hand especially, PTFE wouldbeof interest for reasons of no degradation of the polymer during use and the cost situation (ie., PTFE fier media are quite expensive and as such qualify even more for recycling). But in case of a future ban of the polymer, considerations, and R&D-projects for recycling of used material PTFE do not look promising for the time being. a `Benefits As already mentioned earlier PTFE is used in diferent layouts. The most important fiter media designs based on at least PTFE components and their main advantages are introduced in the: following. Filter media made of 100% PTFE (Fiber layer and support scrim) Needle fels, that consist of 100% PTFE in fier layer and support fabric, are very important problemSolvers in hot-gas filration. They are used when other polymers are not able to deal with the conditions given. Well-known applications are for example fitration plants installed downstream of `combustion plants (e.g. waste incinerations, power plants) when the exhaust gas temperatures, the pollutant gas concentrations andlor the moisture contents are too critical for the other polymers. available and used in filration applications. If required, such a fier medium can also be laminated with an ePTFE membrane, which enables a particularly high separation efficiency for fine dust particles as. willbe explained later in detail One well-known and proven example of a 100% PTFE use is the alkali bypass fiter in cement plants. Herewe are talking about equipment with typically appro. 1800 m*ofiter mediummadeof 100% PTFE. Due to the specific properties of the dust and the gas composition in this application, the temperature must be kept above 200C continuously. At lower temperatures, the consistencyofthe dust cake turns to pasty and sticky and can no lonbegfieerred and cleaned off in intervals. In this `application, the low adhesion tendency of PTFE is also important, which is a specific material property -the adhesionofthe dust cake to the surfaceof a filter media made from PTFE is much lower `compared to other fier media. In addition, high levelsofnitrogen oxides occur due to the process, which cause oxidative damage to other polymers in a short time. The alkali bypass s indispensable to produce high-quality Portland cement in modern European cement plants and must run reliably to safeguard the overall production and thus a production sie at al. Equipping t with a chemically and thermally less resistant materia wil have the immediate consequence that the alkali bypass fiter requires more frequent shutdowns at short intervals to change the damaged fiter bags. Alternatively. a redundant plant concept with practically doubled instalation costs is needed. Consequently, tis would either result in the entire production process having to be shut down, making it uneconomical,o in considerable additional expenditure having to be planned for space, materials, and maintenance with quite similar outcome of economic inefficiency. 5 Woven glass laminated with ePTFE-membrane PTFE is also used and necessary in the form of dispersions in dust collection applications. A very. important use of aqueous PTFE-dispersion is the impregnation of glass fabrics, which makes lamination of an ePTFE-membrane on these fabrics possible at all. Additionally, the PTFE impregnation prevents the glass cloth from a rapid lossoftenacity caused by the wear andtearof the: jet-pulse cleaning process due to reduced frction of the filaments on the supporting cage and in between the single threads of the woven itself by the low friction coefficient and the antiadhesive character of PTFE. The fiter media conceptofwoven glass laminated with ePTFE-membrane is of great economic importance and at the same time has an excellent firation performance even in temperature range up to maximum 200C. Glass woven is avery economic version of hightemperature fier medium and in combination with a PTFE impregnation and an ePTFE-membrane laminated has proven as very effective and long-lasting problem solution. As a standard a glass fabric of 750 g/m weight contains only approx. 10% PTFE add-on after impregnation and drying. The ePTFE membrane conlributes only approx. 2-5 gi? PTFE, but results in surface filration with very high separation efficiency even in the fine particle range. (Results of particle separation efficiency see. `Table 2.and Diagram 1 and 2) In comparison to that a glass fabric without PTFE-based finish and without ePTFE membrane results in more than 10 times the particle emission and a significantly shorter lfetime. Woven glass without PTFE-finish and without membrane laminated is a product used in the past, when higher clean gas. dust concentrations had been accepted as well as less focus on optimized economic solutions. A very. typical field of useofwoven glass laminated with ePTFE-membrane is cement kin filer with ~ as an average - 11.000 sqm installed in one cement kiln line. In caseofrestrictiofn PTFE this concept cannot be replaced adequately because, given the possible. exhaust gas conditions, only needle felt made of 100% PTFE in fiver layer and support fabric could be considered. However, as already indicated and clearly predictedby the restriction proposal in the. actual wording, this product would also be affectedby a ban of PTFE. For the actual emission rates requested by legislation or customers there is no choice besides the PTFE-membrane laminated or a needled felt. A woven without membrane wil result in fairy higher particle emissions and a woven without PTFE-finish in a drastic shortageof fetime due to mechanical stress during the cleaning cycles to less than half. This effects vice versa a doubled amount of waste and far more efforts concerning production, transport, and energy consumption. 6 Impregnation of Needle Felts with PTFE Dispersion Needle Felts have proven very reliable fiter media with millionsof sam produced peryear ~ by various suppliers worldwide. The low statutory emission rates and the even lower partcie emission detected are possible due to extensive R&D-work over decades. Besides the implementation of microfibers, the useofPTFE-impregnation is one crucial factotro reduce particle emission effectively. This effect is experienced and proven over years and could not be realized wih alternatives. PTFE Membranes and fine dust particle separation The by far more important development is the use of biaxially oriented ePTFE-membranes laminated on the dust-side of the filter medium. This was already mentioned and explained with glass woven as. a support structure and is done in the same way with needle felts. PTFE can be used as a glue to attach the membrane. As an alternative a thermoplastic fiber layer canbeused to achieve the bonding of the membrane on the needle felt in case this fiber layer is stable under conditions present in the firation application. There is no other commercial material known to build that extremely fine pores by stretching a fim, resulting into fibrils in nanoscale dimension with a chemically and thermally high stability and low adhesion forces. `The steps forward in particle separation efficiency are demonstrated in the following table and diagrams. There is a comparison of the test results of a standard needle felt consisting of ibers and scrim made from PPS, with a PTFE impregnated fine fiber needle felt (again PPS fibers for support scrim and fier layer) as well as PTFE laminates of different membrane specification. The tests have been performed on a iter test rig in our RED department. 7 Table 2: Comparofipasrtoiclne emissionofdiferent media Verification of Separation Efficiency Figures i pea -on p I e pre on nnreesntacnogneer) ters ne mass swseaarsowe l_sewornme.m |W rworma ens w2 - 72 22 2 " " " - r a an Diagram 1: Particle Emission ofdiferentfiler media 1000000 16573 00000 | 171020 2000 oom | 2600 oo =; 0 PU me MosgseCosr|n Suoneanbmare 2 HFgrhaErmbned60 8 Diagram 2: Pace Size Distibofuemlitoiend Particles sosonomp| -- freee a mows " = teacee pe wr ---- ino| m S fr ------ RA. wou -- mn ei wagoerspes os naearm en The data generated prove clearly that a high-class ePTFE-membrane laminate is capable to bring down fine particulate emissions to a minimum, especially for fine particulate matter (PM 1, PM 2,5). `Consequently, the particle emission can only be detectedbycounting single particles in the clean gas. by light scaterng method instrument, AtypicalPTFE: membrane i ony 2:3 grams per mr, With that small amount of PTFE used, a particle separation ficiency to some single particles per clean gas left canberealized over years even at high temperatures and harsh chemical conditions. The option and benefit to reduce the emissionsoffine dust particles hazardous to health close to detection limit bavy ery small amount of PTFE should be seen in contrast when deciding abanof PTFE fluoropolymer. Other SEAissues As explained for some of the filraton processes tha are cared ou safely over many years wih PTFE fiter media for the actual tate no subsliute media can be used because the operating `conditions (process temperature, pollutant gases, aggressive dust composition) do not permit this. In these cases,abanofPTFE would result in the needofconverting the process, which basically entails the need for plant conversion and thus considerable investment - provided tha- his is technically feasible. Of course, there ia realistic scenario of relocation of those processes outside Europe within short periods of ime, which would result in considerable economic losses inside EU. The almost immediate ossof obs slong the entire process chain in case PTFE as a polymerof unique stabil is 9 producers of PTFE as well as users like automotive induslry (wide range of applications in production process and in cars, no question whether run by fossil fuel or electricity), chemical industry (sealings, reactor lining), as well as several applications necessary for technologies driving the green deal concept fuel cel, green hydrogen production). To clearly stat: the alternative materials will not perform on the same level, will be less durable and unable to meet stringent safety standards. The use of less qualified and proven alternatives with limited stability is potentially hazardous for people and the environment and will cause economic draw backs. Besides these aspects of general health protection, a ban of PTFE would also trigger immense economic repercussions in the flration industry. A banof PTFE in the EU would have a tremendous impact on the company's and competitors' business at all European locations and for the European customers as well "The company markets a quantityof some xx m? of fiter media (figures in the confidential part) made. from 100% PTFE (fibers and support fabric, possibly impregnation and membrane laminated) and more than xix m? membrane laminates (figures in the confidential part) in Europe every year. Most of the volume produced is converted to fier bags at the European subsidiaries and installed in dust collector applications in Europe. For this purpose, sewing thread made of 100% PTFE must be used to assemble the fer bag from the exceptionally thermally and chemically resistant polymer. This exceptional resistance is unmatched by any other known and available material that can be used for dust collection ReqfourExeemsptiton PTFE is a very specific member of the PFAS substance group that seems worth to be looked at separately. The obvious benefits of a use of PTFE inflation applications are discussed in the contribution As PTFE is a very important polymetro be used in processes with harsh conditions and has proven to be able to separate fine dust partices very effectively to almost zero emissions, it should be: considered as an essential material. As the polymer itself isof low concern and does notpose a isk to human health and environment ts requested to consider and hopefully confirm an exemption for PLC's and in particular PTFE at least for essential uses like industrial dust firation applications. iY