Hydrogen-rich carbon recycling complex system establishment and comprehensive evaluation

Abstract

Listen

Translate article

Hydrogen-rich carbon recycling complex system coupling CO2 reduction with waste heat conversion efficiently is becoming a vigorous horizon stepping forward carbon peak and carbon neutrality with great strides in metallurgical industrial sectors. This article originally proposes an in-situ waste plastics gasification complex system utilizing blast furnace flue gas waste heat for hydrogen-rich preparation and CO2 reduction simultaneously, and the effect of parameters such as temperature, pressure, etc. on syngas yield, CO2 conversion rate, etc. are systemically discussed in detail, furthermore, the techno-economic analysis and priorities of this complex system are obtained through originally comparing intensifying factor and substitution coke ratio. The results show that waste plastics conversion rate, hydrogen and syngas yield have a positive relationship with temperature, but opposite with pressure. Hydrogen preparation is intensifying when water vapor is feeding into, and CO yield is augmented when flue gas is injected. The maximum H2 plus CO preparation efficiency is 61.3–77.4% and H2 yield is 95.9–135.5%,when pressure, temperature, H2O/P ratio and CO2/P ratio should be controlled in 1 bar, 800–1000 °C, 1.5–3.0 and 0.1–0.5, respectively, meanwhile, CO2 conversion rate is 28.4%.Otherwise, this complex system has a maximum CO2 reduction efficiency 73.6–99.0%, when 1 bar, 800–1000 °C, 0.1–0.2, 0.1–3.0 are adopted. Under the optimum conditions above, CO2 reduction efficiency is 171.1 kg/t for an ironmaking sector with capacity 54,000 tons, hydrogen preparation efficiency is 15.6 kg/t at 800 °C, corresponding coke ratio substitution amount is 460.0 kg/t. Besides, the maximum H2 preparation intensifying factor is 8.3% at 1000 °C and the maximum CO2 emission reduction intensity factor is 91.0%, which increases by 49.6–71.3% comparing to predecessors. Through this researches above, hydrogen-rich carbon recycling complex system has unique advantages for CO2 deep reduction and coke ratio decrease, and has a significant contribution suppling with a new horizon and methodology for low-carbon metallurgical process development in the future.