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Green Alternative to PVC. Scott Gibb Advisor: Eric Beckman Department of Chemical and Petroleum Engineering. Research Goals. To design a feasible alternative material for replacing PVC piping systems. Develop a process for product design that incorporates a multiple metric system.
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Green Alternative to PVC Scott Gibb Advisor: Eric Beckman Department of Chemical and Petroleum Engineering
Research Goals • To design a feasible alternative material for replacing PVC piping systems. • Develop a process for product design that incorporates a multiple metric system. • Screen potential alternative materials for product design using life cycle assessment. • Eventually prepare and test sample of proposed alternative materials.
Current/Previous Replacements • Polybutylene • PB had problems with oxygen permeation and deterioration of the acetal fittings resulting in leaks that requires entire homes/building to be replumbed. • Borealis • They make polypropylene resins for pipe. • The mechanical properties of Borealis’ pipe resins do not compare to that of PVC. • PP is more expensive than PVC. • Copper • Copper is expensive and requires a skilled laborer to install. (Still the standard for water supply piping)
Why Replace PVC? • Chlorine requires ~3000 kWh/ton to produce. • PVC uses ~1/3 of the world’s chlorine. • Some chlorine production still involves the use of mercury or asbestos. • PVC’s monomer, vinylchloride monomer (VCM), and precursor, ethylene dichloride (EDC), are known carcinogens. • Many environmental pollutants/toxicants are chlorine based.
Chlorine Tree • ~1/3 of Cl2 goes to PVC. • ~1/2 of PVC goes to piping/tubing.
Chlorine Production • Chlorine is produced from a brine solution (salt water) in electrolytic cells. • NaCl + H2O • ½Cl2 + NaOH + ½H2 • There are three types of cells: • Mercury Cells • Diaphragms Cells • Membrane Cells
NaCl + H2O Cl2 + NaOH Cl Cl Cl + HCl + 0.5O2 – H2O PVC Production PVC
How to Replace PVC for Piping • For an alternative material to replace PVC piping, the alternative material must have some advantage over PVC. • Commonly the only advantage consumers care about is upfront cost. • Using only upfront cost in decision making will not likely result in a better product. • It is possible to have a product that is better and cheaper if multiple metrics are assessed during the design of the product. • To achieve this off the shelf alternatives may not work.
Metrics • Functional metric. • Can the alternative material perform the same function as PVC piping? • Does the alternative material have similar, higher or lower values for mechanical strength properties? • Economic metric. • Is the alternative material similar priced or cheaper to purchase, install, and maintain than PVC? • Environmental metric. • Is the alternative material more sustainable and have a lower environmental impact than PVC?
Alternative Comparison • Properties of off the shelf alternative materials and two composites.
Life Cycle Assessment • GaBi LCA software is used to develop LCAs of PVC as well as potential alternatives.
Areas of Overlap with other Disciplines • Mechanical/Material Engineering • Material properties • Civil/Environmental Engineering • LCA • Sustainable design • Industrial Engineering • System design/optimization