METHODS AND SYSTEMS FOR POLYMERIC PARTICLE SIZE CONTROL Russian patent published in 2016 - IPC C08F2/18 C08F2/34 C08F10/00 

FIELD: chemistry.

SUBSTANCE: what is presented is a method for polymeric particle size control involving: selecting a catalyst particle size on the basis of an expected catalyst performance and a target polymeric particle size; and introducing a catalyst having the selected particle size into a loop suspension polymerisation reactor, wherein the above catalyst is used to polymerise a monomer, which is accompanied by formation of a number of polymeric particles in the loop suspension polymerisation reactor. A single polymeric particle size makes from 100 to 500 mcm for 70 to 90 mass percentage of the polymeric particles. A catalyst particle size is selected by means of calculating the above particle size with using formula $$d_c=\frac{d_p}{{\left(P\frac{{\rho }_c}{{\rho }_p}\right)}^{1/3}}$$ (1), where d_c represents the catalyst particle size (mcm), d_p represents target polymeric particle size (mcm), P represents the expected catalyst performance (g of the polymer/g of the catalyst), ρ_c represents a catalyst particle density (g/cm³), and ρ_p represents a polymeric particle density (g/cm³). Producing the polymeric particles having a size of 400 mcm of less requires either (i) the expected catalyst performance making 2000 (g of the polymer/g of the catalyst), whereas the selected catalyst particle size is 32 mcm or less, or (ii) the expected catalyst performance making 10000 (g of the polymer/g of the catalyst), whereas the selected catalyst particle size is 19 mcm or less. The polymeric particle and catalyst particle sizes are determined by means of laser diffraction. The target polymeric particle size can be achieved by using the catalyst having a particle size determined on the basis of the expected catalyst performance.

EFFECT: method enables preventing or limiting reactor plugging caused by coarse polymeric particles; the method may also provide the higher mass percentage of solid matters in the reactor.

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