Particles in bulk chemical distribution system with an internal circulation loop

摘要

Bulk chemical distribution systems have been used for distributing process chemicals with the advantages of high reliability and low impurity concentration in chemicals. The systems by Air Liquide Electronics Systems were evaluated for particle reduction for several different chemicals at user's sites. Each system circulates chemicals through a filter with a pump to reach a maximum particle reduction before the chemicals are transported to pressure vessels for distribution. Particles are further removed with additional filters during the continuous distribution of chemicals with either of two pressure vessels in a system. Particles were counted at different locations for reduction efficiency of filters and minimum circulation time. The systems achieve overall high particle reduction efficiencies and meet the customer's specification for low particle concentrations in chemicals. Measurements showed that filter reduction efficiency varies for different chemicals and different challenge concentrations. A theoretical model was used to simulate particle concentrations during circulation. Minimum circulation time for a steady concentration was calculated with the model and compared with the measurements.