Method for producing dimethyl ether by catalyzing distilled methanol dehydration reaction

The invention discloses a method for producing dimethyl ether by catalyzing a distilled methanol dehydration reaction. In the method, the temperature distribution of a bed layer in a reactor is controlled or adjusted by adopting multi-section backflow, taking heat from cold methanol and segmental methanol feeding; the temperature of a reaction section is controlled at 200-260 DEG C; the methanol undergoes dimolecular dehydration to generate dimethyl ether and water; meanwhile, a part of methanol does not react completely, so that a reaction product and the unreacted methanol move upwards gradually; and when the reaction product and the unreacted methanol pass through each heat taking backflow section, water vapor is condensed into liquid water, methanol vapor is condensed into liquid method, and dimethyl ether serving as an uncondensed gas is exhausted on the top of the reactor at different positions; the purity of the dimethyl ether is over 99 percent; and separation of each substance is finished in one reactor.