EFFICIENCY OF WATER-BASED ELECTROLYSIS DEPENDING ON TECHNOLOGICAL PARAMETERS OF CORROSIVE AND ANODE DISSOLUTION OF ALUMINUM

Abstract

The paper presents the features of the synthesis of hydrogen released as a result of dissolution of the aluminum alloy AMg. To more fully determine the technological characteristics of hydrogen synthesis, we studied the volumes of hydrogen released in the reactor as a result of dissolution of the aluminum alloy AMg. The mechanism of alloy dissolution is established taking into account the effect of impurities in the alloy on the anodic dissolution process. The conditions for accelerating the anodic dissolution of the AMg alloy in the presence of chlorine ions under the conditions of the “negative differential effect” are determined. The dissolution of the AMg alloy in an alkaline chloride solution has an electrochemical nature, which is based on the electrochemical mechanism of hydrogen reduction with the subsequent process of its diffusion into the gas phase. Chloride ions accelerate the active dissolution of aluminum at current densities of 5 A/dm2 instead of 3 A/dm2 at room temperature and surface roughness of class 3-5 (≈5 μm). The greatest influence on the dissolution rate of the alloy has the concentration of NaOH, the dissolution temperature and the surface cleanliness class. The main technological indicator of the improvement of hydrogen electrosynthesis is the use of anodic depolarization of aluminum, its negative values and, as a consequence, the evolution of hydrogen on both electrodes. The depolarization effect is achieved by dissolving the aluminum alloy instead of the oxygen evolution reaction at the anode. The voltage on the cell is 2 times lower compared to industrial alkaline water electrolysis. This makes it possible to save up to 50% of electricity. The absence of oxygen evolution makes this process safer.