Stake Digester Process for HDPE Fuel Tank Recycling

A research project to determine the feasibility of utilizing polyethylene post-consumer automotive fuel tanks as a source of raw material was funded by Visteon, ExxonMobil, and was conducted by Brooks Associates. Brooks Associates launched this project in the last quarter of 2000 to demonstrate the feasibility of utilizing high-density polyethylene (HDPE) post-consumer automotive fuel tanks in combination with wood fiber to create a new material suitable as an automotive substrate. The concept for the project was based on proven technology that processes wood into fiber utilizing steam explosion. The steam explosion process was commercialized to form wood fiber as a raw material for ‘Masonite’. The product of the explosion process has also been made into a mat for further processing. This mat process is generally referred to as the ‘air-lay’ process. The purpose of this project was to add an equal part of post-consumer engineering-grade polyethylene from automotive fuel tanks to determine the viability of HDPE fuel tanks as a raw material source, the potential usefulness of the end products, and in the limitations or consequences of the process. A trial immediately preceding this work demonstrated that plastics taken from a general post-consumer source did process successfully into a fiber mat. That mat was formed into an automotive interior door panel. This trial was designed to determine the feasibility of using post-consumer fuel tanks as the plastics source for this process.