Separation method of dimethyl ether prepared with synthetic gas through one-step process

Abstract

The separation method of dimethyl ether prepared with synthetic gas through one-step process includes condensing the reacted gas in condensator, absorbing un-condensed gas with soft water in the bottom part of the absorbing tower, and making the tower top product tail gas enter to the gas storage tank. The present invention features that dimethyl ether solution as the bottom flow product from the condensator and / or ether aqua as the bottom flow product from the absorbing tower are made to enter the flashing tank, flashed gas is made to enter the bottom of the absorbing tower; and ether solution as the bottom flow product of the flashing tank is made to enter the dimethyl ether rectifying tower to obtain refined dimethyl ether in the tower top and coarse methanol solution in the bottom flow. The present invention has dimethyl ether product purity as high as 98 % and recovering rate as high as 98 %.

Description

Technical field: [0001] The present invention mainly relates to a separation method for the one-step method for preparing dimethyl ether, in particular to a separation method for the one-step method for preparing dimethyl ether from synthesis gas. Background technique: [0002] Dimethyl ether is an important green industrial product that meets today's environmental protection requirements. Its main uses are: clean fuel, aerosol, refrigerant, blowing agent, intermediates of organic synthesis, etc. As a vehicle and general alternative fuel, DME has incomparable comprehensive advantages over natural gas, methanol, ethanol and hydrogen. A large number of research results at home and abroad show that dimethyl ether can directly replace diesel as automobile fuel after liquefaction, and its fuel effect is better than methanol fuel. In addition to the advantages of methanol fuel, it also overcomes its poor low-temperature starting performance and acceleration performance. Shortcomi...

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Problems solved by technology

[0004] The main problem of this technology is that although this method is currently used in the domestic kiloton test device, it cannot run stably and cannot reach the design index, and the gap is large.

For this reason, the quality of the product cannot be guaranteed, and it is difficult to continuously produce

[0006] At the same time, in the absorption tower, the solubility of water to dimethyl ether is very low. The data at 2.0Mpa and 20°C show that the concentration of dimethyl ether in the aqueous solution is less than 2%.

A part of dimethyl ether enters the gas cabinet with the exhaust gas, causing the loss of dimethyl ether

Therefore, the product purity of dimethyl ether cannot reach 98%, and the recovery rate of dimethyl ether in the gas after the synthesis reaction cannot reach more than 95%.

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