CO_2 Capture from Cement Plants Using Oxyfired Precalcination and/or Calcium Looping

摘要

This paper compares two alternatives to capture CO_2 from cement plants: the first is designed to exploit the material and energy synergies with calcium looping technologies, CaL, and the second implements an oxyfired circulating fluidized bed precalcination step. The necessary mass and heat integration balances for these two options are solved and compared with a common reference cement plant and a cost analysis exercise is carried out. The CaL process applied to the flue gases of a clinker kiln oven is substantially identical to those proposed for similar applications to power plants flue gases. It translates into avoided cost of of 23 $/tCO_2 capturing up to 99% of the total CO_2 emitted in the plant. The avoided cost of an equivalent system with an oxyfired CFBC precalcination only, goes down to 16 $/tCO_2 but only captures 89% of the CO_2 emitted in the plant. Both cases reveal that the application of CaL or oxyfired CFBC for precalcination of CaCO_3 in a cement plant, at scales in the order of 50 MWth (referred to the oxyfired CFB calciner) is an important early opportunity for the development of CaL processes in large scale industrial applications as well as for the development of zero emissions cement plants.