Pyrolysis of polystyrene waste in the presence of activated carbon in conventional and microwave heating using modified thermocouple.
Pyrolysis process was experimented using two types of heating source, namely conventional and microwave. Polystyrene (PS) plastic waste was used as feedstock in a batch reactor for both the conventional (slow pyrolysis) and microwave pyrolysis. The effect of activated carbon to polystyrene ratio on (i) yield of oil, gas and residues (ii) reaction temperature (iii) reaction time were studied. Quality of oil from pyrolysis of polystyrene were assessed for the possible applicability in fuel production. Microwave power of 450 W and polymer to activated carbon ratio of 10:1, resulted in the highest oil yield of 93.04 wt.% with a higher heating value of 45 MJ kg-1 and a kinematic viscosity of 2.7 cSt. Microwave heating when compared to conventional heating method, exhibits a reaction temperature and time of 330 °C in 5.5 min, whereas in conventional heating system it was 418 °C in 60 min. The gas chromatography-mass spectrometry analysis of liquid oil from microwave pyrolysis predominantly yields alkenes of 8.44 wt.%, α-methyl styrene 0.96 wt.%, condensed ring aromatics 23.21 wt.% and benzene derivatives 26.77 wt.% when the polystyrene to activated carbon ratio was 10:1. Significant factor of using microwave heating is the amount of energy converted (kWh) is lesser than conventional heating.
Microwave-assisted pyrolysis of sewage sludge: A review
Abstract Microwave-assisted pyrolysis is considered a promising technique for the thermochemical conversion of solid waste such as sewage sludge to useful energy products, including bio-char, bio-oil and bio-gas. However, a limited number of reports are found on the fundamentals and application of this process to extend the high potential of microwave-assisted pyrolysis of sewage sludge. This article presents up-to-date knowledge regarding important aspects of sewage sludge microwave pyrolysis, starting with the pretreatment of sewage sludge and the latest studies of conventional and microwave pyrolysis heating. This article further explores the products generated by microwave-assisted pyrolysis for sewage sludge including composition and yield. For instance, recent progress in experimental studies of both the catalytic and non-catalytic microwave-assisted pyrolysis of sewage sludge are reviewed and their results are analyzed in comparison to the product distributions resulting from non-microwave heating methods. Finally, this review discusses both the advantages and challenges of sewage sludge pyrolysis using microwave heating and the milestones that are necessary to be obtained in the future.
Conventional and microwave-assisted pyrolysis of biomass under different heating rates
Abstract Biomass was subjected to conventional and microwave pyrolysis, to determine the influence of each process on the yield and composition of the derived gas, oil and char products. The influence of pyrolysis temperature and heating rate for the conventional pyrolysis and the microwave power was investigated. Two major stages of gas release were observed during biomass pyrolysis, the first being CO/CO 2 and the second one CH 4 /H 2 . This two-stage gas release was much more obvious for the conventional pyrolysis. While similar yield of liquid was obtained for both cases of conventional and microwave pyrolysis (∼46 wt.%), higher gas yield was produced for the conventional pyrolysis; it is suggested that microwave pyrolysis is much faster. When the heating rate was increased, the peak release of CO and CO 2 was moved to higher reaction temperature for both conventional (500 °C) and microwave pyrolysis (200 °C). The production of CH 4 and H 2 were very low at a conventional pyrolysis temperature of 310 °C and microwave pyrolysis temperature of 200 °C (600 and 900 W). However, at higher heating rate of microwave pyrolysis, clear release of CH 4 was observed. This work tentatively demonstrates possible connections and difference for biomass pyrolysis using two different heating resources (conventional and microwave heating).