A new CO2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid

A new disposal process for anthropogenic CO: via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps: (1) CaSiO3 + 2CH(3)COOH --> Ca2+ + 2CH(3)COO(-) + H2O + SiO2. (2) Ca2+ + 2CH(3)COO(-) + CO2 + H2O --> CaCO(3)down arrow+ 2CH(3)COOH. Step (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions by CO2 injection. The Gibbs free energy change of each step is negative; the reactions would proceed spontaneously without consuming large amounts of energy. The CO2 would be captured from the concentrated emission sources such as thermal power plant, and be disposed of and sequestrated in the form of calcium carbonate. The feasibility of the proposed process was evaluated through a process design based on the experimental results of the reaction kinetics. The operational energy consumption was 20.4 MW for the disposal of CO2 produced by a 100-MW thermal power plant. (C) 2001 Elsevier Science Ltd. All rights reserved.