Iranian Journal of Chemical Engineering (IJChE)

Abstract In the present study, the main focus was on plasma pyrolysis and gasification of organic waste, specifically polyethylene and cotton waste and exploring the energy recovery possibilities from the gases obtained after the plasma pyrolysis and gasification. In pyrolysis the gases formed are Syn gas (H2 + CO), CH 4, higher hydrocarbons along with soot particles. The waste is disintegrated using thermal plasma (which is generated using graphite plasma torch) in oxygen starved environment (pyrolysis) and also in partial oxidation condition (gasification). Experiments have been carried out by varying pyrolysis chamber temperature from 500 0C to 700 0C and polyethylene and cotton are fed into the pyrolysis chamber. It has been observed that plasma pyrolysis of polyethylene in the temperature range of 500 to 700 0C yields H 2 as main component around 30-40% volume basis along with CO, CO2, CH 4, C2H 6, C2H 4, C2H 2 and soot particles whereas pyrolysis of cotton, on the other hand provides less H 2 around 15-20 %. However, it has also been observed that in plasma gasification H2, CO, CH 4 content in the exhaust gases reduces to some extent (2-5%). The theoretical and experimental energy recovery comparisons have also been carried out.

Abstract A mathematical model is developed for describing the dynamic behavior of the gas phase ethylene polymerization reactor. The model is based on the dynamic two-phase concept of fluidization in which the bubbles may contain solid particles and the emulsion is capable of containing more gas than that of minimum fluidization. The fluidized bed reactor is divided into several serial sections consisting of bubble and emulsion phases. Flow of the gas is considered as plug flow through the bubbles and perfectly mixed through the emulsion phase. Polymerization reactions occur in both emulsion and bubble phases. Variation of the process variables as well as the polymer properties were studied as a function of operating time. The bed height was controlled by the product withdrawal rate with a PID controller. The results of the model were compared with the experimental data and a good agreement was observed between the model prediction and actual data. The simulation results indicate that a significant amount of polymer production (roughly 12%) takes place in the bubbles.