Akzo Nobel Steam Gasification Process

If tars are formed (which happened in the trial with mixed PVC waste), it is necessary to apply a partial oxidation to convert these tars into gaseous products. Via a quench, HCl is recovered from the product stream which consists of fuel gas and HCl. After purification the HCl can be used for producing ethylene dichloride (EDC) via oxychlorination. The recovery of CI2 is more then 90%, in general 94%-97%. Inert materials in the feed, such as the chalk and metal stabilisers present in a PVC-formulation, are separated from the flue gas as fly ash or will be set free as a bleed from the circulating sand. 

The final output of the reactor is a synthesis gas. The composition will depend on the input. If much polypropylene (PP) and polyethylene (PE) is present, relatively high amounts of ethylene and propylene will be formed. If mainly PVC is present, HCl and CH4 

The testing does not yet allow for setting specific input criteria. However, the testing made clear that the process probably can handle a broad spectrum of materials, such as wood, biomass, mixed plastic and pure PVC waste. For instance tests have been done on PVC waste but also with a mixture of PVC, PE, other polymers, Cu, Al, chalk, cement and fibres. 

The exact need for resources and the emissions will depend in part on the input of the process. On the basis of the tests thus far, for a waste containing 40% PVC and 25% inorganic fillers, the data shown in Table 2 can be estimated (amounts per tonne of PVC). 

As for a gate fee, estimates are difficult to give. Costs are dominated by the investment costs, which Akzo estimates at 25 million for a 50,000 tpa plant. There exists a large uncertainty in this estimate. For instance, if the feed also included brominated or fluorinated compounds, extra cleaning steps would be needed which would greatly enhance the investment. It is simply too early to give a good estimate of costs per toime for treatment. 

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Akzo Nobel steam gasification process (Netherlands) ... 

Table 2 Inputs and outputs for 40% PVC/25% inorganic fillers waste processing in the Akzo Nobel steam gasification process per tonne of PVC ...

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