Chemical systems and methods for operating an electrochemical cell with an acidic anolyte

摘要

An electrochemical cell having a cation-conductive ceramic membrane and an acidic anolyte. Generally, the cell includes an anolyte compartment and a catholyte compartment that are separated by a cation-conductive membrane. A diffusion barrier is disposed in the anolyte compartment between the membrane and an anode. In some cases, a catholyte is channeled into a space between the barrier and the membrane. In other cases, a chemical that maintains an acceptably high pH adjacent the membrane is channeled between the barrier and the membrane. In still other cases, some of the catholyte is channeled between the barrier and the membrane while another portion of the catholyte is channeled between the barrier and the anode. In each case, the barrier and the chemicals channeled between the barrier and the membrane help maintain the pH of the liquid contacting the anolyte side of the membrane at an acceptably high level.

主权项

1. An electrochemical cell, comprising:
an anolyte compartment comprising an acidic anolyte solution and an anode in contact with the acidic anolyte solution; a catholyte compartment comprising a basic catholyte solution and a cathode in contact with the catholyte solution; an alkali cation-conductive ceramic membrane positioned between the anolyte and catholyte compartments; and a cation permeable, porous diffusion barrier disposed in the anolyte compartment, the diffusion barrier separating the anolyte compartment into a first anolyte space, located between the cation-conductive ceramic membrane and the diffusion barrier, and a second anolyte space that holds the anode, the first anolyte space and the second anolyte space containing the acidic anolyte solution, the diffusion barrier slowing the rate at which chemicals in the acidic anolyte solution pass between the first and second anolyte spaces and mix with each other, the first anolyte space having a first fluid inlet and a first fluid outlet other than the diffusion barrier, and the second anolyte space having a second fluid inlet and a second fluid outlet other than the diffusion barrier; and a first flow of the anolyte solution that passes through the first anolyte space and out the first fluid outlet and a second flow of the anolyte solution that passes through the second anolyte space and out the second fluid outlet.