Optimization of a membrane process for CO_2 capture in the steelmakingindustry

摘要

Three different types of membranes were experimentally evaluated for CO_2 recovery from blast furnace effluents: a semi-commercial adsorption selective carbon membrane, an in-house tailored carbon molecular sieving membrane, and a fixed site carrier (FSC) membrane with amine groups in the polymer backbone for active transport of CO_2. In the single gas experiments the FSC membranes showed superior selectivity for CO_2 (more than 140) over the other relevant gases (CO, N_2 and H_2) and high CO_2 permeance (productivity). In addition, it is easy to process and handle, relatively inexpensive to produce, and the water in the feed gas is no problem, rather an advantage, since the membrane must be humidified during operation. Based on these experiments a simulation study of a full scale process was performed. The technology showed notable low energy cost, even when converted to the thermal equivalent. Total costs for the CO_2 recovery unit (CO_2 prepared for pipeline transport) were estimated to be in the range 15.0 to 17.5 €/ton CO_2.