Success of Thermoplastic Piping Systems in the Water Treatment Industry

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Success of Thermoplastic Piping Systems in the Water Treatment Industry Riccardo Barbone Georg Fischer Piping Systems Ebnatstrasse 111, Schaffhausen, 8201 Switzerland, Switzerland riccardo.

Since then, plastic piping system products have continually been developed in accordance with market and regulatory requirements and today are uniquely positioned to provide suitable materials as

1 Success of Thermoplastic Piping Systems in the Water Treatment Industry Riccardo Barbone Georg Fischer Piping Systems Ebnatstrasse 111, Schaffhausen, 8201 Switzerland, Switzerland ABSTRACT Over 50 years ago, the handling of harsh chemicals represented one of the first applications for plastic piping systems. Since then, plastic piping system products have continually been developed in accordance with market and regulatory requirements and today are uniquely positioned to provide suitable materials as well as cost-effective and safe methods for handling most fluids in many industries and markets and namely the fast growing water market. The success of thermoplastic valves is due to the fact that they are in some cases the only solution to the water treatment industry, while in other instances offer a viable replacement for traditional materials like metal when one factors in total cost of ownership, safety, reliability, efficiency and carbon footprint. This paper examines the basic selection criteria of thermoplastic piping systems with special emphasis on material compatibility, valve function, maintenance and the benefits of thermoplastic piping systems from an environmental perspective. INTRODUCTION The water treatment business is a 225 billion dollar business 1 and touches many sub-industries ranging from food and beverage to textiles. Water treatment is relevant in all water usage across all industries. Therefore the systems used to manage, supply and treat water are highly important. A majority of the piping systems in the water treatment market employ metal piping systems. While metal piping systems have their place in high pressure and temperature applications, over the last 30 years plastic piping systems have made great strides in establishing themselves as a superior alternative in many applications. The use of thermoplastics piping systems in water treatment is growing due to the excellent corrosion resistance and reduced maintenance and the fact that available thermoplastic materials offer substantial solutions that meet the technical application requirements but also offer advantages and alternatives to meet the increasing demands of water, energy and environment conservation. Plastic valves offer a safe, reliable and efficient solution for the supply, management and treatment of water. Safety, Reliability and Efficiency are cornerstone for the rapid ascension of thermoplastic piping systems. Figure I: Piping materials used in water treatment market Figure II: Breakdown of global water use

PROCESSES APPLICATIONS REQUIREMENTS The typical tater treatment plant is comprised of many sub-systems each requiring unique solutions for day-to-day operations.

2 PROCESSES APPLICATIONS REQUIREMENTS The typical tater treatment plant is comprised of many sub-systems each requiring unique solutions for day-to-day operations. These sub-systems typically include: raw water inlet, pretreatment, filtration, water finishing, disinfection, storage, waste disposal, maintenance and distribution to the grid or point of use amongst others. Figure III: Sub-systems in water treatment & typical processes Regardless of the process the key is to have a reliable system in place that will ensure performance and peace of mind. Breaking down the water treatment process elements into basic application building blocks allows one to start to appreciate the benefits of plastic piping systems. Control, performance, reliability, safety, flexibility are all important factors to consider in any process and the decision of what type of piping system to use originates mainly from the application requirements. These can be summarized as follows: Decision Factors Physical Pressure Temperature (internal) Temperature (external) Temp fluctuation s Flow Rates Water Hammer Exothermic Function Open / Close Control / Dosing Sampling Divert Operation Cycles Actuatio n Operatio n Cycles Media Type Neutral (Water, viscosit y) Hygienic (Food, Pharma) Slurry, Viscosity Suspended Particles Abrasive / Powder Gas / Vapor Vacuum Media Acid Base Halogen Salts Fuel / Oil Solvents Phenols Engineering Design Training Installation Operate Maintenance Repair Retrofit Table I: Typical application parameters used in piping system selection Thermoplastic piping systems and valves can cover most if not all these aspects plus more. It is within this context that we will review the benefits of thermoplastic piping systems.

PHYSICAL PARAMETERS MATERIAL SELECTION OPTIONS There are countless applications within water treatment that fall within the pressure / temperature range of where thermoplastics can offer safe,

Figure IV: Pressure Temperature boundaries of Thermoplastic piping systems The specific limits are determined by the material and valve selected.

3 PHYSICAL PARAMETERS MATERIAL SELECTION OPTIONS There are countless applications within water treatment that fall within the pressure / temperature range of where thermoplastics can offer safe, reliable and efficient solutions to the industries most challenging applications. Material technology developments will extend this range further in the near future. Figure IV: Pressure Temperature boundaries of Thermoplastic piping systems The specific limits are determined by the material and valve selected. But as a general reference, typically thermoplastic can be utilized within the pressure band of bars (350 PSI) and within the temperature band of 140 ºC (280 F). MEDIA TYPE / FUNCTION VALVE TYPE SELECTION Selecting the right valve clearly depends on the application requirements. Combing function and media type one can the need for various types of valves 5, ball valves to diaphragm valves, all of which are readily available in thermoplastics. The table below gives a basic overview of valve types and their intended purpose and functionality. Table II: Media type and valve function parameter used for valve selection

SAFETY - CHEMICAL compatibility MATERIAL SELECTION Material compatibility in conveying, handling and mixing different fluids, chemicals is a major aspect of any chemical water treatment plant and

Figure V: Extreme corrosion on metal valve As an example the chemical distribution and dosing of acids, chlorine and bromine place tough demands on water treatment plants and are the source of many

4 SAFETY - CHEMICAL compatibility MATERIAL SELECTION Material compatibility in conveying, handling and mixing different fluids, chemicals is a major aspect of any chemical water treatment plant and choosing the right piping materials combined with the right systems is paramount. Figure V: Extreme corrosion on metal valve As an example the chemical distribution and dosing of acids, chlorine and bromine place tough demands on water treatment plants and are the source of many corrosion problems with annual damages due to corrosion amounting to approx. 50% of maintenance costs 2. Annual damage by corrosion in high industrial countries amounts to close to 4% of the GNP. 3 With chemical usage amounting to approx. 60% acids & alkali, 15% solvents, 15% solids and 10% other, it becomes quite evident that not all materials will satisfy all the requirements. Plastic piping systems and valves are available as a full plastic solution in all the common plastic materials (PVC-U, PVC-C, ABS, PP, PVDF, PFA) with numerous joining options such as cement, electro, socket butt fusion and BCF (bead crevasse free fusion), threaded, flanged and also including PE end connectors. Usage of thermoplastics in water treatment plants is growing due to the improved corrosion resistance and reduced maintenance and the fact that available thermoplastic materials for valves will cover most of the chemical resistance requirements. Table III: Chemical resistance of piping system materials When the pressure and temperature requirements are fulfilled, high quality thermoplastic systems offer an alternative to metal valves requiring exotic and expensive alloys which are orders of magnitudes more costly. Thermoplastic valves generally do better than metal valve in highly corrosive environments. Externally, airborne corrosive fumes or condensation issues are not prone to occur on plastic piping systems and valves. Internally, rust, scaling and other corrosive build up are also not typical issues in plastic piping systems and valves, eliminating sticking and valve functionality failures.

EFFICIENCY - CONTROL ACTUATION After material and valve selection, the next most important aspects in any chemical process is the control and actuation of the system.

Full plastic solutions exist also in actuation. From control valves, to pneumatic and electric actuators, thermoplastic valves are well complimented with plastic solutions for actuation.

Figure VI: Pneumatic actuated thermoplastic valve Figure IX: Chlor-Alkali Process Application Manual thermoplastic valves with integrated position feedback to control to open and close positions can

5 EFFICIENCY - CONTROL ACTUATION After material and valve selection, the next most important aspects in any chemical process is the control and actuation of the system. Ratio control or batch mixing, dilution, dosing or neutralization of ph, all require the right equipment to control the process consistently and reliably. Full plastic solutions exist also in actuation. From control valves, to pneumatic and electric actuators, thermoplastic valves are well complimented with plastic solutions for actuation. While some internal components are still in metal (for the time being), they are for the most part sealed and not exposed to the piping system elements as well as external corrosive fumes. Figure VI: Pneumatic actuated thermoplastic valve Figure IX: Chlor-Alkali Process Application Manual thermoplastic valves with integrated position feedback to control to open and close positions can be used for processes that are not regularly changed. Whereas for processes such as chemical dosing or neutralization one may need more precision and maybe even real-time feedback control. This is accomplished through the use of fully automated electric and or pneumatic valves. Today modern thermoplastic valve platforms offer all these plus unlimited possibilities through modular systems with electric, pneumatic actuators and multi-functional modules and handles. The usage of thermoplastic valves in the water treatment processes is far and wide and includes Media filtration systems, aids pre-treatment chemical feeding systems, antiscalant of acidification control for Membranes based processes, membranes racks sampling manifolds as well as the treatment of a wide range of liquid wastes to satisfy government regulations. The Chlorine Sodium Hypochlorite (NaOCl) dosing applications are very representative of the thermoplastic materials benefits Due to the highly corrosive nature of chlorine and sodium hydroxide both piping and valves utilized must be chemically resistant. Metal valves are PVDF Body PTFE Shell Figure X: Section cut on butterfly valve

typically constructed from elaborated metals (titanium alloys, zirconium, cupro nickel, super duplex) and used for corrosive, toxic and abrasive service environments.

In fact this is where thermoplastic solutions are best suited.

6 typically constructed from elaborated metals (titanium alloys, zirconium, cupro nickel, super duplex) and used for corrosive, toxic and abrasive service environments. They are expensive, heavy and are very specialized in their construction and normally lined with PTFE. Thermoplastic piping & valve solutions also exist for these harsh environments. In fact this is where thermoplastic solutions are best suited. Combing the excellent pressure-temperature and chemical resistance of PFA with PTFE offers the ideal combination to meet the Chlorine process applications in a safe, reliable and efficient way. Figure X shows a full PVDF butterfly using the double eccentric principle with a PTFE shell for the disc seal. Chemical resistance, reliable abrasion resistance, reduced operating torques.all possible with thermoplastic valves. RELIABILITY MAINTENANCE Maintenance of Water treatment plants especially in long terms DBO, DBOT contracts models is a costly endeavor and problems often require down-times and loss in production. Having a system that performs reliably with less maintenance cycles is to be expected these days, especially when time and costs are becoming more and more determining factors in profitability. Having a system that is made of high quality raw materials and performs reliably with less wear and tear is essential. When you factor in the cost of installation, corrosion remediation costs and the wide range of material selection and joining techniques, the benefit of plastic piping systems and thermoplastic valves becomes evident. The annual cost of corrosion remediation in the United States exceeds 150 billion dollars per year 4, with the typical corrosion related damage caused by mechanical failure followed by cracking and pit corrosion. Figure XI: Corrosion damage within industrial applications Thermoplastic valves offer not only protection from corrosion but also have unique advantages over metal valves and piping systems, such as lower thermal expansion rates, lower thermal conductivity, no electrical conductivity, lower installation weights than metal valves. See Appendix. Figure XII: Failed joints per 100 km of installation

RESPONSIBILITY THINKING AND ACTING GREEN The carbon footprints of plastics are advantageous over traditional piping materials.

While alone they cannot solve the global issues on water, environment and energy, thermoplastic piping systems offer out of the box solutions that can significantly contribute to environmentally

With total plastic solutions you avoid these losses, save a lot of potable water.

7 RESPONSIBILITY THINKING AND ACTING GREEN The carbon footprints of plastics are advantageous over traditional piping materials. Less energy to produce and recyclable, materials like plastics are an important element in reaching global environmental targets. While alone they cannot solve the global issues on water, environment and energy, thermoplastic piping systems offer out of the box solutions that can significantly contribute to environmentally sound solutions Figure XIII: Carbon Footprint of piping materials Within Europe water losses of 20 % from leaking steel pipes are typical. With total plastic solutions you avoid these losses, save a lot of potable water. Thermoplastic piping systems typically have 15+ times fewer leaks compared to steel according to the DVGW Statistics (Germany 1995) leaks/km per year Plastics <> Steel. Thermoplastic piping solutions offer long-lasting system solutions without leaks, Reliable jointing technologies and typical 25+ year system lifetimes. Figure XIV: Large thermoplastic installations When one factors the better internal surface roughness and lower leach out rates, it becomes clear that thermoplastic piping systems play an important role in the water treatment Industry. Some plastic valves are even designed with a buttress thread design on all plastic threads (including union bushing) while others permit a lower operating torque due to a superior ball sealing construction. There are also super long life options with cycles for those maintenance free but critical applications. Figure XV: Buttress thread design Overall, thermoplastic valves and related accessories offer a versatile system that incorporate the latest

plastic material innovations and offer a flexible platform to meet the most challenging manual and fully automated applications.

piping systems have exceeded their half-century mark and grown in acceptance there remain future opportunities to further extend its reach into this traditional metal world.

8 plastic material innovations and offer a flexible platform to meet the most challenging manual and fully automated applications. Across the globe in countless of chemical applications, ranging from highly caustic environments to nuclear power plants you will find thermoplastic valves performing day in day out, safely, reliably and efficiently. FUTURE OUTLOOK While the thermoplastic valve has exceeded its halfcentury mark and grown in acceptance in the Water Pipes Fittings Jointing Technologies Valves FUTURE OUTLOOK While thermoplastic piping systems have exceeded their half-century mark and grown in acceptance there remain future opportunities to further extend its reach into this traditional metal world. Thermoplastic materials are in constant evolution and the next generation of products will continue to make inroads and gain a greater market share wherever highly aggressive, corrosive or high purity media are used in the water treatment industry. Automation Measurement and Control When you combine material technology advances with new product designs and the economics of total cost of ownership thermoplastic systems are beginning to catch up and will exceed traditional materials like metals in the strive to meet and exceed existing and future water treatment and environmental requirements. Figure XVI: Material technology advances in plastics

9 REFERENCES 1. Global Water intelligence Water treatment Capex Forecast Economics of Corrosion. NACE 3C Houston, TX, NACE International. 3. Uhlig HH. The Cost of Corrosion in the United States. Chemical and Engineering News 1949; 27: Koch, G. H, Brongers, M. P. H., Thompson, N. G., Virmani, Y. P., and Payer, J. H. Corrosion Costs and Preventive Strategies in the United States. FHWA-RD Springfield, VA, National Technical Information Service. 5. Valve Selection Handbook, Fifth Edition: Engineering Fundamentals for Selecting the Right Valve Design for Every Industrial Flow Application, Gulf Professional Publishing; 4 edition (December 31, 1998) 6. Handbook of Chlor-Alkali Technology, O'Brien, Thomas F., Bommaraju, Tilak V., Hine, Fumio2005, LXXXVI,

10 APPENDIX - METAL & PLASTIC PIPING SYSTEMS PROPERTY METAL THERMOPLASTIC Density Thermo Conductivity Electro Conductivity High density - need a crane to carry it - wide distance of supports - high anchor forces, strong supports Thermo-conductive - energy losses need for isolation - condensation and medium chemical resistance causes corrosion Electric-conductive - galvanic corrosion risk Low density - carried by hand until d low distance of supports - low anchor forces, easy and economical Low thermo-conductivity - low heat conductivity, thermal insulation - less condensation, high chemical resistance avoids corrosion No electric-conductivity - no corrosion Chemical Resistance Temperature Resistance Medium chemical resistance bad resistance against acids alloys needed costly Excellent chemical resistance combined with right jointing technology life times of 25+ years for the piping system are typical Highest temperature resistance Temperature resistance max. up to 140 C Pressure Resistance Surface Roughness Purity / Leach out Engineering / Installation Production Methods Maintenance High pressure resistance Have a rough surface - have pressure losses - risk of incrustation and rouging for high purity applications, SS is needed. Leach out tests show bad results compared to PVDF HP (high purity) Mechanical or welding joining Casting, formed - Machining on sealing surfaces High maintenance cost - painting, replacement due to corrosion, production stops Limited pressure up to 16 bar Have a smooth surface - through a higher flow rate the DN of the pipe can be reduced - incrustation risk limited, no rouging highest purity - most suitable piping system for high purity applications within microelectronic, food, life science and chemical process industries. Wide range of joining methods, Reliable, Easy and Safe Plastic Injection Moulding - Fully moulded - None if little machining Lowest maintenance costs Table IV: Basic differences between metal and plastic valves Note to reader: The information contained in the entirety of this paper is for basic reference and is only intended as a guideline and does NOT replace a detailed material recommendation for your application and from your supplier. This information is based on our experience and state-of-the-art knowledge of piping systems. These data are general indicators for orientation, whereas for practical use other factors such as concentration, pressure or jointing technology influence the results. The technical data are not binding and not expressly warranted characteristics of the stated products and are subject to change.

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