Selection of Desulfurization Pumps in Different Desulfurization Processes

Limestone - Gypsum desulfurization process

Process characteristics: Limestone slurry is used as a desulfurization agent to react with sulfur dioxide in the flue gas to form gypsum. The process has high desulfurization efficiency, up to more than 90%, and is widely used, but the system is relatively complex. The slurry contains a certain amount of solid particles, which has high requirements for the wear of the desulfurization pump.

Key points of pump selection

Material selection: Overflow components should be made of materials with good wear resistance, such as high chrome cast iron, rubber lining, etc. High chromium cast iron has good wear resistance and corrosion resistance, and can effectively resist the erosion of solid particles in the slurry; rubber lining can buffer the impact of particles and reduce wear.

Impeller type: Open or semi-open impeller can be selected. The open impeller is not easy to block, can adapt to slurries containing more solid particles, and is easy to repair and replace; while ensuring a certain flow capacity, the semi-open impeller can also provide better hydraulic performance and improve the efficiency of the pump.

Sealing form: mechanical seal is preferred, and double-end mechanical seal should be used. By introducing sealing water or sealing oil, an effective sealing barrier is formed to prevent slurry from leaking, and to improve the reliability and service life of the seal.

Ammonia desulfurization process

Process characteristics: Liquid ammonia or ammonia water is used as desulfurizer to react with sulfur dioxide to form by-products such as ammonium sulfate. This process has high desulfurization efficiency and fast reaction speed. The by-products can be used as chemical fertilizers and have certain economic benefits, but ammonia is volatile and has high requirements for the system's sealing.

Key points of pump selection

Material selection: Because ammonia is corrosive, the material of the pump should be corrosion-resistant stainless steel or plastic lining material. Stainless steel material can resist ammonia corrosion to a certain extent, while plastic lining materials can provide more comprehensive corrosion protection to ensure that the desulfurization pump operates in an ammonia environment for a long time and stable operation.

Sealing requirements: High-performance mechanical seal or magnetically driven seal. For mechanical seals, you should choose sealing materials and structures suitable for ammonia medium to ensure the tightness of the seal; magnetic drive seals achieve contactless transmission through magnetic transmission, completely avoiding the problem of shaft seal leakage, and are especially suitable for ammonia desulfurization systems with strict leakage requirements.

Flow and head: Accurately calculate the required flow and head according to the scale and process requirements of the desulfurization system. Generally speaking, the flow rate and head of the desulfurization pump in the ammonia desulfurization process are relatively high to meet the circulation and transportation needs of ammonia liquid.

Magnesium oxide desulfurization process

Process characteristics: Magnesium oxide slurry absorbs sulfur dioxide to produce magnesium sulfite and magnesium sulfate. Magnesium sulfate products can be obtained through oxidation and crystallization. This process has high desulfurization efficiency, stable system operation, and wide sources of magnesium oxide, but the treatment and recycling of magnesium sulfate requires certain technology and equipment.

Key points of pump selection

Material considerations: You can choose a rubber lining pump or stainless steel pump. The rubber lining of the rubber lining pump can effectively prevent the slurry from corrosion and wear on the pump body, and is suitable for magnesium oxide slurry containing solid particles; stainless steel pumps have good corrosion resistance and strength, which can meet process requirements.

Impeller design: Large channel impeller is used to ensure that the solid particles in the slurry can pass smoothly and reduce the possibility of blockage. At the same time, the design of the impeller should take into account the crystallization characteristics of substances such as magnesium sulfate to avoid affecting the performance of the desulfurization pump due to crystallization.

Shaft seal form: Use a reliable shaft seal system, such as a containerized mechanical seal. This seal form is easy to install and has a good sealing effect. It can effectively prevent slurry leakage and ensure the normal operation of the pump.