Working principle of Laboratory Electrolyzer
When the direct current passes through the Laboratory Electrolyzer, an oxidation reaction occurs at the interface between the anode and the solution, and a reduction reaction occurs at the interface between the cathode and the solution to prepare the desired product.
The distance between the anode and the cathode is one of the important factors that affect the voltage of the Laboratory Electrolyzer. As the electrode spacing increases, the ohmic voltage drop in the slot increases, and the slot voltage increases. Especially when working with high current, this voltage loss is more serious. Modern Laboratory Electrolyzer adopts various measures to reduce the distance between electrodes, such as the use of diffusion anodes and modified diaphragms to make a zero-pole-distance electrolytic cell structure.
The residence time of the electrolyte in the Laboratory Electrolyzer not only affects the production capacity of the equipment, but also affects the current efficiency of the electrolysis process in some cases, such as the production of sodium chlorate by electrolysis, due to the intermediate product hypochlorous acid (HClO) and secondary The chemical reaction between chlorate ions (ClO3) is very slow. If left in the electrolyzer for a long time, it will not only reduce the utilization of Laboratory Electrolyzer, but also hypochlorite ions will be oxidized on the anode surface or reduced on the cathode surface, reducing current efficiency . Therefore, the modern Laboratory Electrolyzer design strives to reduce the volume so that the electrolyte flows quickly along the electrode. If further reaction is needed, a separate chemical reactor can be installed outside the electrolytic cell.
The inner electrode of Laboratory Electrolyzer is more compact with vertical installation, the conductive plate is easy to connect, and it is helpful to reduce the bubble effect. Because there are often bubbles on the surface of the electrode where gas is precipitated, it will reduce the working surface area of the electrode. In addition, the solution near the electrode will also be filled with bubbles, increasing the resistance of the solution. This phenomenon is called the "bubble effect". However, near the surface of the vertical electrode, the characteristics of high aeration in the solution, low solution density and fast rise speed can be used to form a natural circulation of the electrolyte, which accelerates the bubbles to leave the electrode surface and reduces the bubble effect. When the vertical electrode is used as a gas electrode, the shape of the electrode is mostly mesh, which not only increases the working surface area, but also facilitates the escape of bubbles.
Laboratory Electrolyzer materials can be steel, cement, ceramics, etc. Steel is resistant to alkali and is the most widely used. For the corrosive electrolyte, the steel tank is lined with lead, synthetic resin or rubber.
At present, Laboratory Electrolyzer is developing in the direction of large capacity and low energy consumption. Bipolar electrolyzers are suitable for large-scale production and have been successively adopted by the water electrolysis and chlor-alkali industries.