Study of CO₂ Capture Applied to Integrated Steelmaking

Technical and financial models were made of a generalized 4 MT/year Reference steelplant and three Steelplants applying CO₂ capture. Two post-combustion capture cases where modelled where CO₂ was captured from hot stove and steam boiler flue gases (Level 1) and then extended to include coke oven and lime plant flue gases (Level 2). Chemical solvent systems using 30% MEA and advanced heat integration were assumed. A third case was modelled whereby the conventional blast furnaces were replaced with Oxygen Blast Furnaces with CO₂ capture from OBF top gas using chemical solvent of 40% MDEA and 10% piperazine. Cost estimates were made to determine the break-even cost of hot rolled coil production at a scoping level using a discounted cash flow method. The cost of avoidance was calculated from the difference in CO₂ emissions and HRC breakeven costs. The results show that the OBF scenario offers the most cost effective capture solution at 56 USD/t CO₂ avoided at 47% avoidance rate. The post-combustion cases avoidance costs were 74 and 81 USD/t CO₂ at 50% and 60% avoidance rates. Avoidance costs were sensitive to energy prices and capital cost.