The volume contains three technical notes relating to the limestone injection wet scrubbing process (LIWS). The first concerns the calculation of the enthalpy of aqueous ionic solutions. It outlines the method for calculating enthalpy: The thermodynamic basis, the derivation of the equations for the difference between ideality and reference state, and the means of selecting the reference states. A comparison is made between experimental and calculated values. Next a description is presented of the Radian process model for the prototype LIWS system. This technical note presents a description of the Radian process model. A brief description of the LIWS process with regard to its relationship to the process model is followed by listing of the model assumptions and parameters. Included is a detailed description of the model. Finally equilibrium calculations for Type I APCO inhouse experiments are given. This technical note gives the results of equilibrium calculations made during analysis of data from SO2 scrubbing experiments.