Preparation method and apparatus for methyl methacrylate

A method for preparing methyl methacrylate, comprising following steps:

• step (1), mixing a ninth material stream with a sixth material stream and a twelfth material stream to obtain a tenth material stream, performing an aldol condensation reaction in a reactor to obtain a first material stream, wherein the ninth material stream is methyl propionate and a catalyst is provided in the reactor;
• step (2), heating and distilling the first material stream through a first distillation equipment, obtaining a third material stream from a bottom outlet of the first distillation equipment and a sixteenth material stream from a top outlet of the first distillation equipment, heating and distilling the sixteenth material stream through a second distillation device, obtaining a second material stream from a bottom outlet of the second distillation equipment and an eleventh material stream from a top outlet of the second distillation equipment, wherein the third material stream is a crude product of methyl methacrylate;
• step (3), mixing a eleventh material stream with a fifteenth material stream and a seventh material stream to obtain a fourth material stream, heating and distilling the fourth material stream and the second material stream through a third distillation equipment, obtaining a sixth material stream from a bottom outlet of the third distillation equipment and a twelfth material stream from a top outlet of the third distillation equipment, circulating the sixth material stream and the twelfth material stream to step (1) for preparing the tenth material stream, obtaining a thirteenth material stream from a side outlet of the third distillation equipment, obtaining a fifth material stream and a fourteenth material stream through a phase splitting of the thirteenth material stream, circulating the fourteenth material stream to the third distillation equipment, wherein the fifteenth material stream is a formalin solution;
• and
• step (4), heating and distilling the fifth material stream through a fourth distillation equipment, obtaining a seventh material stream from a top outlet of the fourth distillation equipment, circulating the seventh material stream to step (3) to prepare the fourth material stream, and obtaining an eighth material stream from a bottom outlet of the fourth distillation equipment.