Polyacrylamide (PAM), general known as flocculants, is the linear polymers with the molecular weight between 5-25 million. Its solid product appearance is white or slightly yellow powder, while its liquid is no colored viscous emulsion. This products is easily soluble in water and decomposed when the temperature is more than 120 ℃.
The positive group (-CONH2) in polyacrylamide molecule could easily adsorb and bridge with the dispersion of suspended particles in the solution which makes it a strong flocculation characters. That’s why polyacrylamide could be widely used in water treatment, paper, mineral processing and other fields. While what we discuss today is not about the application as above fields. Polyacrylamide could also be used be effective friction reducer in Oil & Gas field.
Friction reducer, or called drag reducing agents are the agents that could reduce the resistance of a fluid to transport which are mostly water-soluble or oil-soluble polymer. Actually 200 years ago, people already found that the viscosity of the skin of the marine animal has drag reduction effect, and even more the turbid water flows faster than the clean water. And also there was evidence that there would be smaller surface friction when the ship was in the water with algae. Based on above observation and study, in last century, scientists found that certain natural resins, linear polymers, organic soaps, etc. could reduce turbulence friction in different levels. The term of ‘friction reducer’ or drag reduction is first time cited the since then. Along with the technology development, scientists found that polymer dilute solution or elastic material surface can achieve reduction and the boundary shear turbulence generated by the basic laws is closely linked. The viscous drag reduction is either by changing the boundary conditions of the fluid from the outside or by changing the boundary conditions from the inside. By changing the physical, chemical, mechanical properties of the boundary material or by injecting the gas, liquid and liquid with different physical, chemical and mechanical properties in the near, could change the flow and kinetic characteristics of the near-wall region, so as to achieve the purpose of drag reduction technology.
