Depolymerization feed costs

For this study, an economic hurdle rate of 15 % before tax return on capital investment was used. This rate is higher than for the flake feed preparation facility because the depolymerization facilities cannot be as easily converted to other uses as can the flake preparation plants, which can be converted to produce mechanically cleaned PET for traditional post-consumer PET uses. Including the total capital return component, and a 12 year economic depreciation component, the total cost of the products are given in Table 16.4 as US 1.07/kg to US 1.32/kg. 

In those jurisdictions where money is specifically collected from consumers to underwrite the costs of recycling plastic containers, funds may be available to offset some costs of depolymerization. If bottles are provided at no cost at the sorting/baling facility, an economically attractive venture can be contemplated, but still at a large scale. Securing the feed on a long-term basis at a favorable price will require significant co-operation. 

Any post-consumer plastic stream will contain some halogens in the form of polyvinyl chloride, polyvinylidene chloride, brominated flame retardants, halogenated additives, food waste, or salt. Therefore, two issues must be considered. First, the gas stream resulting from the depolymerization of plastics must be scrubbed to remove any halogenated gases to satisfy emissions controls. Second, halogens in the liquid product must be minimized to increase its value and marketability. Therefore the Conrad process has been developed. It is a robust process unit that can accommodate a variable feedstream and produce a consistent product, free of nonhydrocarbon impurities by low feed preparation costs. 

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