The invention relates to a 
new energy-saving technique and a device for composing 
dimethyl ether by utilizing carbinol, which is characterized by integrating the separation of a 
reaction product and a substance not reacted as well as the gasification of the raw materials into a 
tower to be carried out simultaneously. The device of the invention consists of a 
reaction system and a dividing wall rectification column; the dividing wall rectification column is provided with a block of 
clapboard on the vertical direction in a normal rectification column; thereby dividing the inner cavity of the rectification column into four areas which are an upper area, a lower area, a left area and a right area; a 
dimethyl ether product is obtained from the top parts of the 
reaction product and the substance not reacted output from the 
reaction system after being separated by the dividing wall rectification column; a 
gas phase logistics taking carbinol as a main component is obtained from a side line as the incoming stock of the 
reaction system; while the water in the 
system is discharged from the bottom of the rectification column; simultaneously, the 
raw material, carbinol, containing unpurified water enters the rectification column from the right side of the dividing wall to obtain the carbinol and the water in 
gas phase. The invention can be used for various manufacture techniques and devices by using the carbinol in 
gas phase to catalyze and compose the 
dimethyl ether, can reduce device investment to a large extent, simplify the flows as well as reduce 
energy consumption and operation cost.