As we all know, sulfuric acid is a kind of strong corrosive acid, so its production conditions are very bad, and the requirements for corrosion resistance of equipment are very high. The application of plate heat exchanger not only expands the application field, but also plays an important role in the development of sulfuric acid industry.
Before the use of plate heat exchanger, there were two kinds of sulfuric acid production processes, i.e. sulfuric acid production by sulfur and sulfuric acid production by flue gas tail gas. Among them, the cooling equipment used in absorption tower and drying tower is acid cooler, which is a spray cooler outside the cast iron exhaust pipe. Its disadvantages are low heat transfer coefficient, large floor area, high energy consumption, serious corrosion, frequent maintenance and technical problems.
The following problems should be paid attention to when selecting plate heat exchanger:
1. Sulfuric acid is a dual chemical characteristic, i.e. it will be oxidable and reductive due to the change of concentration. It is oxidable when it is concentrated, reductive when it is dilute, and the corrosiveness will increase with the change of temperature. Under such conditions, the material selection of plate heat exchanger should be careful or it will cause significant consequences.
2. Because the thickness of the plate of the heat exchanger is relatively thin, frequent inspection is required, and the service life and safety cannot be determined only in theory.
3. Sulfuric acid will also produce corrosion, and it is even corrosion. The service life of the equipment can be extended by lowering the rings at the acid inlet and water outlet. Moreover, it is not allowed to cut off the water, which is easy to damage the equipment.
4. Split flow can be used to accelerate the cooling effect, but safety shall be ensured.