A techno-economic study to evaluate the impacts of feedstock ratio on commercial scale co-pyrolysis plants of biomass and waste tire

Six types of commercial-scale pyrolysis and co-pyrolysis plants for rice straw (RS) and waste tire (WT), with a capacity of 20 tons/hour, have been modeled based on experimental data. The impact of a range of feedstock ratios on the techno-economic performance of the plants is comprehensively studied. The capital investment of plants ranged between $17.0 and $19.9 million with Plant A (RS only) having the lowest and Plant E (20 % RS and 80 % WT) having the highest value. The operating cost was found to be lowest for Plant A and highest for Plant F (100 % WT) due to the procurement cost of WT. Pyrolytic-oil and char are the main revenue streams while gases are combusted to generate the energy required for the pyrolysis reactor and preheating of feedstock. Plant E is the most economical alternative with the highest gross margin, highest net present value and lowest payback time of 7.06%, $ 5.63 million and 6.23 years respectively. Sensitivity analysis indicates that oil selling price and WT procurement cost are the most influential factors affecting economic returns.