CO2 Capture from Steel Gases ‒ using Pressure Swing Adsorption model in Aspen AdsorptionTM

Abstract

ABSTRACT Industry and Petroleum refineries are among the most significant contributors to anthropogenic CO2 emissions. Within the industry, the iron and steel industry is the most energy-consuming manufacturing sector. Iron and steel production is still primarily coal-based, thus dependent on fossil fuels responsible for CO2 emissions. In 2020, the global iron and steel industry has emitted about 2.6 Gt of CO2, about 8.3% of the world's CO2 emissions. Mitigating these total CO2 emissions while steel production continues to rise is the major challenge for the iron and steel industry. Therefore, carbon capture is essential to enable the use of carbon while reducing CO2 emissions into the atmosphere. Tata Steel Ijmuiden is exploring various CO2 capture technologies for their CO2 emission mitigation, including physical adsorption. As such, this thesis is aimed to establish the benchmark numbers for the performance of a PSA unit capturing CO2 from a gas mixture of blast furnace gas and basic oxygen furnace gas. The PSA unit was modelled using aspen adsorption software, where the physical adsorption takes place on selected zeolite 13X particles. The model has been validated with experimental data from the literature and optimised in an extensive parameter study. The system operated between 15bar and 0.1 bar pressure, and the operating temperature was the same as the feed gas temperature, 288 K. To process 24104 kmol of feed gas per hour, 390 trains of two parallel adsorption beds were required with a length of 9 meters and a diameter of 0.75 meters. The PSA system had a specific energy demand of 1,87 GJ per tonne of CO2 captured for its pressure reduction and increase. Ultimately, 1.9 million tonnes of CO2 is captured in this system annually, with a recovery rate of 84%. The CO2 purity, on the other hand, is 94%mols.