The invention provides a
system and a method of preparing propylene
tail oil by value-added exploitation of
methanol. The comprises a first reactor, a second reactor, a product separation unit, a c 4
hydrocarbon extraction, rectification and separation device and a
heating furnace, wherein the first reactor performs
dimethyl ether preparation reaction with
methanol to form a first product flow; the second reactor synthesizes propylene by using a material from the
heating furnace as a
raw material to form a second product flow; the product separation unit receives and separates the second product flow to form propylene, c 4
hydrocarbon, a c 5 / c 6
hydrocarbon mixture and
ethylene; the c 4 hydrocarbon extraction, rectification and separation device separates at least part of c 4 hydrocarbon to form a butylene product flow; and the
heating furnace receives and heats at least part of first product flow, at least part of butylene product flow, at least part of c 5 / c 6 hydrocarbon mixture and at least part of
ethylene. The
system and the method can reprocess butylene alone, and supplement the removed
butane part with the c 5 / c 6 hydrocarbon mixture; the reprocessing quantity of the
tail oil is increased; the yield of propylene is increased; the value-added exploitation of the
tail oil is achieved; and
economic benefits are raised.