Modeling and economic analysis of waste tire gasification in fluidized and fixed bed gasifiers

Waste tires have an organic-matter composition of more than 90% and have been proposed as an excellent calorific fuel material. The objective of this study is to find an economic and efficient pathway for producing syngas by waste tires gasification. To achieve this goal, two most commonly used gasifier types of fluidized bed and fixed bed have been simulated and compared by using a semi-empirical model and a one-dimensional kinetics model, respectively. Moreover, economic analysis of the levelized cost of syngas is used to compare economic indicators of different gasifiers. Results show that the lower heating value of the tire-syngas product is 2.5-7.4 MJ/Nm³, moreover, equivalence ratio and tire mixture ratio have negative impacts on syngas heating value and syngas efficiency. Furthermore, the levelized cost of syngas of tire gasification is 0.33-0.60 ¢/kWh that is lower than the market price of natural gas at 0.68 ¢/kW, which indicates tire gasification is a potential technology for syngas production. Finally, compared with the fluidized bed tire gasification, the fixed bed tire gasification has worse performance but better economic indicators, indicating that fixed bed gasification is an economic pathway for the syngas product.