The application of polyacrylamide covers a wide range of fields, from sewage purification in water treatment to oil displacement agent in oil exploitation to soil improvement in agriculture. Due to its unique physical and chemical characteristics, polyacrylamide plays an important role in industry, especially in the fields of environmental protection and resource recovery.
Production Technology of Polyacrylamide
There are two main production processes of polyacrylamide: solution polymerization and emulsion polymerization. Solution polymerization is the most common production method and widely used in industrial production.
Solution polymerization method: Solution polymerization method is to polymerize acrylamide monomer in aqueous solution through free radical polymerization to generate polyacrylamide. This method is suitable for the production of water-soluble polyacrylamide, and the process is usually simple, and the reaction temperature is controlled between 30℃ and 60℃.
Steps
Dissolve acrylamide monomer and add initiator.
Reacting at a certain temperature to generate polyacrylamide solution.
By-products were removed by neutralization, purification and other processes to obtain water-soluble polyacrylamide.
Finally, a powdery final product is formed by spray drying or freeze drying.
Emulsion polymerization method: emulsion polymerization method is to obtain dispersed polymer particles by polymerization in the mixed medium of water and organic solvent. This method is suitable for the production of polyacrylamide with strong hydrophobicity, and is usually used to prepare oil displacement agents in oil fields or polyacrylamide products in special fields.
Steps
Adding emulsifier into the water phase to form oil-water emulsion.
Free radical polymerization is carried out in emulsion to produce emulsion polymer.
The required polyacrylamide particles were obtained by centrifugal separation, drying and other methods.
Other methods: In addition to solution polymerization and emulsion polymerization, some new methods have been developed, such as suspension polymerization and solid phase polymerization. These methods are usually used for special application requirements, but their industrialization degree is low.
Application Field of Polyacrylamide
Polyacrylamide has been widely used in many industries because of its excellent water solubility and adjustability. The main application fields include:
Water treatment field: Polyacrylamide is widely used in sewage treatment, wastewater purification, drinking water treatment and other occasions. As an efficient flocculant, polyacrylamide can aggregate suspended particles in water into larger flocs, which is convenient for sedimentation or filtration, thus achieving the effect of water purification. According to its molecular weight and charged properties, polyacrylamide can be divided into cationic polyacrylamide flocculant, anionic polyacrylamide flocculant and nonionic polyacrylamide types, which have different application effects in different water treatment processes.
Petroleum exploitation: In petroleum exploitation, polyacrylamide is used as oil displacement agent and stabilizer. As a thickener, it can effectively improve the viscosity of water injected into the oil field, and then improve the oil recovery. In addition, polyacrylamide is also used as a rheological modifier in oil well mud to help stabilize the mud system and avoid wellbore collapse.
Paper manufacturing: Polyacrylamide is used to increase the strength and surface quality of paper in the paper industry. As a sizing agent and thickener of paper, it can improve the fluidity of paper pulp, reduce the loss in the production process of paper and improve the water resistance and moisture resistance of paper.
Mineral processing: In mineral processing, polyacrylamide is used as mineral processing aid. It can be used as polyacrylamide flocculant and flotation agent to help mineral separation and improve recovery. Especially in the processing of coal, iron ore and bauxite, polyacrylamide has been widely used.
Agriculture and soil improvement: Polyacrylamide is used in agriculture to improve soil structure and enhance soil water-holding capacity. By combining with water molecules in soil, polyacrylamide can slow down water evaporation and improve water supply for crop growth. It can also be used as a soil improver to improve the air permeability and water permeability of soil.