Views: 0
Ion exchange membranes are selectively permeable. It only allows Na + to pass through with a small amount of water molecules, and it is difficult for other ions to pass through. During electrolysis, a strictly refined NaCl solution is injected into the anode chamber from the lower part of the electrolytic cell, and water is injected into the cathode chamber. In the anode compartment, Cl - discharges to generate C1 2 , which is released from the top of the electrolytic cell, while Na + carries a small amount of water molecules through the cation exchange membrane and flows to the cathode compartment. The H+ discharges in the cathode chamber to form H2, which is also released from the top of the cell. However, the remaining OH - cannot move to the anode compartment due to the barrier of the cation exchange membrane, so it is gradually enriched in the cathode compartment to form a NaOH solution. With the progress of electrolysis, refined brine is continuously injected into the anode chamber to supplement the consumption of NaCl; water is continuously injected into the cathode chamber to supplement the consumption of water and adjust the concentration of the product NaOH. The resulting lye is led out from the upper part of the cathode compartment. Because the cation exchange membrane can prevent the passage of Cl -, the NaOH solution generated in the cathode compartment contains very little NaCl impurities. The products prepared by this method have higher concentration, higher purity and lower energy consumption than those produced by diaphragm electrolysis, so it is the most advanced chlor-alkali production process at present.
The composition of ion exchange membrane electrolyzer: It is mainly composed of anode, cathode, ion exchange membrane, electrolytic cell frame and conductive copper rod; each electrolytic cell is composed of several unit cells in series or in parallel. The anode is made of metal titanium mesh. In order to prolong the service life of the electrode and improve the electrolysis efficiency, the anode mesh is coated with oxide coatings such as titanium and ruthenium; the cathode is made of carbon steel mesh and coated with nickel coating; The electrolytic cell is divided into a cathode compartment and an anode compartment.
The electrodes are all mesh-shaped, which are rough and can increase the contact area of the reaction. The special treatment of the anode surface is to consider the strong corrosiveness of the anode product Cl2. From the perspective of the current development of ionic membrane electrolysis technology in the world, the use of natural circulation bipolar cells, high current density,
The large-scale unit area and zero (membrane) pole distance are its direction, so this project recommends the use of natural circulation high current density repolarization cell technology.
Ion membrane electrolyzer is the key equipment of ion membrane technology. At present, there are many cell manufacturers in the world with ionic membrane caustic soda production technology, such as Wood Nora, a joint venture between Wood of Germany, Wood of Wood and De Nora of Italy, Asahi Kasei of Japan, CEC of Chlorine Engineering of Japan, INEOS of UK And Beijing Chemical Machinery Factory imported technology from Japan's Asahi Kasei Company, digested, absorbed and improved and produced domestically produced Beihua mechanical and electrical tanks. Among them, Asahi Kasei, Chlorine Engineering Co., Ltd. and Wood Nora Co., Ltd. have won the ion-exchange membrane caustic soda project in China with their patented technology of ion-exchange membrane electrolysis process, high-performance electrolyzer, stable quality, high cost performance and good after-sales service. more contract projects.
●The "independent unit" design structure composed of anode half-shell, cathode half-shell and ion membrane is easy to replace the battery, the repair time is short, and the longest storage time of the main assembled unit can be up to 2 years.
●The welding of the cell unit is automatically welded by laser, which is uniform, has good current contact, and has a stable service life, which is beneficial to operation under high current density.
●The material of the electrolytic cell is well used, the anode is made of titanium material, and the cathode is made of nickel material, which has a long service life.
The unit area is 2.7 m2, and the operating current density is generally 5~6KA/m2, which is suitable for operation under high current density. ●
There are many alarm chains in the system design, and the safety is thoughtful.
B. Chlorine Engineering Company BiTAC® Cell Features
●The bipolar electrolysis device has a simple structure.
The electrode wave structure, the electrolyte distribution and current distribution are more uniform, lower voltage drop, power consumption low, high current density operation.
●Low operating pressure, overflow, safe operation
●The material of the electrolytic cell is good, the anode is made of titanium material, and the cathode is made of nickel material, and the service life is long.
●The unit area is 3.276 m2, and the operating current density is generally 5~6KA/m2, which is suitable for operation under high current density.
Asahi Kasei is the only company in the world that can simultaneously provide customers with ion-exchange membrane electrolysis technology and ion-exchange membranes.
●The plate and frame of the electric cell is a filter press type (composed of many unit cells in series), and the power supply circuit is formed independently.
●The operating pressure of the electrolyzer is the highest among the companies, which is beneficial to the post-process treatment.
●The material of the electrolytic cell is good, the anode is made of titanium material, and the cathode is made of nickel material, and the service life is long.
●The unit area is 2.7m2, and the suitable current density is 4.5~5.5KA/m2.
