Conversion of municipals waste into syngas and methanol via steam gasification using CaO as sorbent: An Aspen Plus modelling

The conversion of wastes specially (plastic and food waste) for energy and value-added products through gasification is under investigation. This investigation configures an integrated simulation process model for steam gasification, syngas treatment, methanol production and purification for plastic waste ((Polyethylene(PE) + polyethylene terephthalate (PET)), food waste (vegetable and fruits) and their blend using a simulation tool Aspen Plus (R). The impact of three process parameters such as temperature (650-900 degrees C), steam/feedstock ratio (1.0-2.0) and CaO/feedstock ratio (0.5-2.0), on syngas composition and downstream product methanol. H2 and methanol yield increases with the increase of temperature in all cases. In the case of plastic, H2 and methanol yield were increased from 75.68 to 92.77 kmol/h and 709.60 to 960.13 kg/h respectively with the injection of steam fiowrate. A similar H2 and methanol yield trend was obtained for food and mixture of plastic and food waste with a little variation. In the case of food waste, methanol has ascending order and maximum final methanol production 476.56 kg/h at 1800 kg/h steam fiowrate. The gas composition profile which define the H2CO/CO + CO2 ratio increase from 1.27 to 1.88 governing methanol production for plastic. CaO is added to capture the CO2 to get the augmented syngas composition for methanol production. The general trend of H2 production was ascending, whereas methanol is descending with an increase of temperature and CaO fiowrate for most cases. Maximum 978 kg/h MeOH noticed at temperature of 700 degrees C, steam fiowrate of 1000 kg/h and CaO fiowrate of 500 kg/h for plastic. Although, its fiowrate extensively affected the CO and CO2 fiowrates that need to be optimized for a desired composition to maintain a good H2-CO/CO + CO2 ratio for methanol production.