As a necessary equipment in the chemical industry, electrolyzers are often corroded by chemical substances. Over time, the performance and service life of the electrolyzers will be affected, especially for production safety issues. Therefore, it is imperative to take certain anti-corrosion measures to protect the device. Nowadays, some companies adopt anti-corrosion measures such as rubber and plastics and vulcanized butyl rubber, but the anti-corrosion effect is not satisfactory. Most of the initial anti-corrosion effect is obvious, but the anti-corrosion time can only be maintained for 1-2 years, and the damage effect is serious in the later stage.
From the technical and economic aspects, the glass fiber composite bar is the best choice as the anti-chemical corrosion material of the electrolytic cell anti-corrosion layer. In addition to excellent mechanical properties, glass fiber composite bars are also excellent in chemical resistance. With their excellent properties, they have been favored by chlor-alkali industrial enterprises. As the most widely used and most widely used corrosion-resistant material, glass fiber composite bars are suitable for use in various equipment in contact with chlorine, alkali, hydrochloric acid, salt water, water and other media.
In this article, we will briefly describe the application of a glass fiber composite bar with glass fiber as the reinforcing material and resin as the matrix material in the anti-corrosion layer of the electrolytic cell.
2. Analysis of corrosion damage factors of electrolytic cell
The reason for the corrosion of the electrolytic cell is not only affected by the material, structure and furnace construction technology of the electrolytic cell itself, but the most important reason is the influence of the external corrosive medium. Generally, the corrosive media that affect the electrolytic cell are: high temperature wet chlorine gas, high temperature sodium chloride solution, chlorinated alkali solution and high temperature saturated chlorine water vapor. At the same time, they are also corroded by stray current during electrolysis.
The high-temperature wet chlorine gas produced in the anode compartment of the electrolytic cell will bring out a large amount of water vapor, and the hydrolysis of the chlorine gas will generate highly corrosive hydrochloric acid and highly oxidizing hypochlorous acid. The generated hypochlorous acid can be decomposed again, releasing new ecological oxygen. The chemical properties of these media are very active. Except for titanium, most metal and non-metal materials will suffer severe corrosion in this environment. The original anti-corrosion measures of our factory are steel-lined natural hard rubber, its temperature resistance range is 0-80℃, which is lower than the corrosive environment temperature, and the natural hard rubber is not resistant to hypochlorous acid corrosion, the lining layer is very easy to suffer in the vapor-liquid environment Corrosion damage, causing the metal shell to corrode and perforate and fail.
3. Performance of glass fiber composite bars
The tensile strength of glass fiber composite bars is more than twice that of ordinary copper bars and steel bars of the same specification; its density is between 1.25-2.1g/cm3, which is only about 1/4 of conventional ordinary steel bars.
The low density of the glass fiber composite bar reduces the weight of the construction project itself, making the transportation, construction and installation process more convenient; the glass fiber composite bar has a very high tensile strength, and the composite bar will not be produced when the ultimate tensile strength is reached. Substantial deformation; glass fiber composite ribs are easy to cut, and construction is convenient: the cutter head can be directly cut, and various standard and non-standard parts of different specifications can be produced according to different engineering requirements.
4. Application of glass fiber composite bars in electrolytic cell
4.1 Characteristics of glass fiber composite bars
The glass fiber composite bar is made of glass fiber as the reinforcing material, resin as the matrix material, and mixed with appropriate auxiliary agents (such as crosslinking monomers, initiators, accelerators, alteration agents, flame retardants, polymerization inhibitors, fillers) , Pigments, etc.) A new type of composite material formed by pultrusion and special surface treatment①.
In addition to the excellent mechanical properties of glass fiber composite bars, its chemical properties are also better among several fiber composite materials, especially its corrosion resistance to acid and alkali solutions is unmatched by any other fiber material products. Secondly, the glass fiber composite bar is non-conductive, non-conductive, and has good acid and alkali corrosion resistance. Its thermal expansion coefficient is small, and it has good elasticity and toughness. The combination of glass fiber and resin further strengthens the corrosion resistance of the glass fiber composite bar. . Formally due to the outstanding chemical properties of glass fiber composite ribs, it becomes the best choice of anti-corrosion materials for electrolytic cells.
4.2 Structural design of glass fiber bars in the electrolytic cell
In the electrolytic cell, the glass fiber tendons are distributed parallel to each other in the tank wall; and the vinyl resin concrete is poured between the glass fiber composite tendons to solidify and form a whole. In this way, the electrolytic cell is made stronger, has better acid and alkali chemical corrosion resistance, large space in the cell, good insulation, reduced maintenance times, and extended service life, especially suitable for strength, bending resistance, and tensile resistance. Strong electrolysis process.
4.3 Advantages of using glass fiber bars in electrolytic cells
At present, the anti-corrosion method of the electrolytic cell is mainly to use resin to pour the concrete electrolytic cell or to line the wall of the concrete cell with FRP. However, because the quality of the concrete electrolyzer is too heavy, the maintenance period is too long. The glass fiber reinforced plastic lining on the inner wall can only be prepared by manual pasting, which is extremely inefficient, and the density of the glass fiber reinforced plastic layer is low. It is easy to bubble in the electrolytic tank and is unstable. , The electrolyte is easy to leak and corrode the concrete electrolytic cell, which affects normal production, pollutes the environment, and wastes a lot of manpower and material resources for repeated maintenance. Moreover, the transportation cost of FRP anti-corrosion electrolyzer is relatively high, and installation and maintenance are extremely inconvenient.
The use of glass fiber composite bars as the corrosive material of the electrolytic cell can overcome the disadvantages of the original electrolytic cell of heavy weight, small bearing capacity, easy corrosion, bending resistance, tensile resistance, and acid and alkali corrosion resistance. At the same time, electrolysis The tank has sufficient capacity, high carrying capacity, long service life, few maintenance times, and the tank is light and delicate, easy to lift and transport.
The glass fiber composite bar combines the excellent mechanical, physical and chemical properties of resin and glass fiber. Now it has been widely used to solve the corrosion problem of concrete structures in the chlor-alkali industry, tunnels, roads, and bridge decks. Through the meticulous detection and identification of the electrolytic cell using glass fiber reinforcement, it is possible to know scientifically and objectively that the application of glass fiber composite reinforcement can enhance the corrosion resistance and service life of the electrolytic cell, while improving the safety of production. Therefore, this application has broad prospects and is worthy of widespread promotion.