| Abstract |
A method (SOLVEQ-pH) was developed using SOLVEQ in evaluating the amount of base (NaOH) or acid (H2SO4) added to thermal fluids. In this method, pH is changed, as the charge balance is re-adjusted to compensate for the given pH. It is the adjustment of the charge balance, using a pre-selected ion, that makes this method useful in computing amount of a particular base (such as NaOH) or acid (such as HCl or H2SO4). For addition of base, Na ion (assuming addition as NaOH = Na+ + OH-) is added as the charge balancer while for acid addition, Cl- is added as the balancer (assuming addition as HCl = H+ + Cl-). For acid like H2SO4, one can also use Cl ion as the balancer, provided its adjusted mole is divided by two by the concept neutralization-equivalent-weight or simply the equivalent of H2SO4 to HCl: there are two equivalents per mole of H2SO4 per mole of HCl. Based from the results, SOLVEQ-pH can evaluate not only the needed dosage of acid or base treatment, but also show the intricacy of the chemical equilibrium involved in the procedure by comparing the computed from actual data. To-date, although measurements of pHÆs at laboratory condition remain the only method of choice in evaluating required dosages, SOLVEQ-pH strengthens our understanding of the real conditions that affect the treatment: for NaOH, fluxes in condensate flow and the role of Eh are essential parameters to monitor effectiveness of the treatment, while for H2SO4, the line-temperature dictates the strength of acidity, hence the amount of dosage. |