PURPOSE: To continuously separate high-purity paraxylene by fractionating the charge raw material contg. C8 arom. hydrocarbon with an adsorption apparatus of a simulated moving bed, separating paraxylene by crystallization, isomerizing the other fractions, then recovering and recirculating the product.
CONSTITUTION: The charge raw material contg. methaxylene, paraxylene, ethylbenzene and in some cases, orthoxylene, and a zeolite adsorption bed in ≥1 simulated moving bed adsorption zones 8 are fractionated to a first fraction contg. the solvent, methaxylene, ethylbenzene and orthoxylene and a second fraction contg. the solvent and paraxylene in the presence of a desorption solvent of 1.2 to 2.5 in the flow rate with respect to the flow rate of the charge raw material and thereafter, the first fraction is distilled in a distillation apparatus 12 and is then isomerized in the presence of hydrogen in an isomerization application 21. The isomerized matter is distilled in a distillation apparatus 21 and is recalculated to the adsorption zones 8. The second fraction is distilled in a distillation apparatus 16 where the fraction is separated to the solvent and the paraxylene having purity of 75 to 98% purity. The paraxylene is crystallized at +10 to -25°C in a crystallization apparatus 5.
KUROODO RUU GERA
TAN GUEN TAN
