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Abstract:Conversion of waste plastics (Polypropylene) into hydrocarbon fuel was investigated by using a reactor system which consists of a reactor, a condenser and a liquid-gas separator. A maximum waste to fuel conversion of over 99% has been achieved with approximately 47% of liquid yield and 52% of gas yield. The liquids and gasses obtained from the experiments were analysed using a gas chromatograph/mass spectrometer unit (GC/MS). Analysis results show that the escaped gas is non condensable at ambient temperature and mainly consists of methane, propylene, isobutane and isobutylene. The analysis results also show that the liquid obtained in the experiments consists of many linear, branched and aromatics hydrocarbon compounds in the range of C5 to C10.Waste polypropylene samples different in weight were used for the experiments to investigate the effects of batch size on the reaction time and the liquid yield at near atmospheric slightly positive pressure. No N2 purging or vacuuming of the reaction zone was used at the start of the experiments. The experimental results showed that the percentage of liquid yield increase with the increase of batch size. The experimental results also showed that the reaction time of 500 g batch size was 100 minutes and that was increased approximately by 15 minutes for every additional 500 g of sample fed into the reactor in respective batches.

Circular vibration milling (CVM) is achieved by vibrating a milling cutter about the machine tool spindle axis in a circular path, in addition to its rotary motion. CVM has been proven capable of producing better surface finishes on difficult to cut materials. However, the CVM process is far slower than conventional milling process. In circular vibration planing (CVP) process, the cutting tool is clamped without rotation and fed at a speed comparable to the feed speed of conventional milling. By superimposing circular vibration motion, necessary cutting speed could be achieved keeping the feed speed at realistic values. Inconel 718 was machined by CVP and conventional milling at a similar feed rate. It was observed that CVP could reduce tool wear and hence produce better surface finishes than conventional milling. A geometric simulation showed a major difference between uncut chip shapes of the two processes. The difference of uncut chip shapes suggests that in CVP process, less rubbing occurs between tool flank face and work before the tool penetrates in to the work to form a chip. The reduced rubbing of the flank face is proposed as the reson for reduced tool wear in CVP when compared with conventional milling.

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