Light dydrocarbon preparation method and light dydrocarbon preparation system with methyl alcohol as raw materials

The invention relates to a light dydrocarbon preparation method with methyl alcohol as raw materials, and further relates to a light dydrocarbon preparation system in which the method is adopted. The method comprises the steps that heat exchange and heating are carried out on the raw materials, methyl alcohol, and discharged materials of a synthesis reactor through an inlet and outlet heat exchanger, and then methyl alcohol and the discharged materials are conveyed into a methyltertiarvbutyl ether reactor; meanwhile, circulating gas is conveyed into the methyltertiarvbutyl ether reactor, the reaction temperature of the methyltertiarvbutyl ether reactor is controlled through the circulating gas conveyed into the methyltertiarvbutyl ether reactor, after heat recycling and cooling, the discharged materials of the synthesis reactor enter a three-phase separation system, and most of a gaseous phase separated out by the three-phase separation system is used as the circulating gas after being boosted by a gas compressor. The preparation system comprises a feed conveying pipeline, the methyltertiarvbutyl ether reactor, the synthesis reactor, the three-phase separation system and an after-separation system capable of separating fuel gas, liquefied gas, light dydrocarbon and heavy oil out of corresponding oil phases. The technological process is simple, control difficulty is low, energy consumption is low, and product quality is high and stable.