A process for refining propane from a feed stream comprising propane and dimethyl ether

Abstract

The invention relates to a process for refining propane from a raw material flow containing propane and dimethyl ether. The process sequentially comprises the steps of performing dimethyl ether removing treatment, rinsing treatment and dehydrating treatment on a raw material flow containing propane and dimethyl ether, wherein in the dimethyl ether removing phase, the raw material containing propane and dimethyl ether is extracted and rectified by utilizing organic oxy-compound or aqueous solution thereof as an extracting and rectifying solvent; the primary refined propane material flow obtained by extraction and rectification is fed into the rinsing phase for rinsing, and organic oxy-compound and residual trace dimethyl ether formed by azeotropy are rinsed away; and the material flow containing dimethyl ether and organic oxy-compound is obtained at the bottom of the dimethyl ether removing phase, and gaseous-phase refined propane material flow is obtained at the top of the rinsing phase and is condensed and dehydrated to obtain the refined propane product. Compared with the prior art, the process has the advantages that the refined propane product can be used as a raw material for propane dehydrogenation and light hydrocarbon cracking or used as liquefied petroleum gas, so that the utilization value of the raw material is greatly increased.

Description

technical field [0001] The invention relates to a propane purification process, in particular to a process for refining propane from a raw material stream containing propane and dimethyl ether. Background technique [0002] Propane and dimethyl ether are commonly found in the reaction effluents produced by various industrial processes for oxygenate conversion such as oxygenate-to-olefins (OTO), methanol-to-olefins (MTO) and oxygenate-to-gasoline, Since the boiling point of dimethyl ether (-24.8°C under normal pressure) is not much different from the boiling point of propane (-42.0°C under normal pressure), the two generally exist during the subsequent rectification and separation of these reaction effluents. In the same stream, it is difficult to separate the two through ordinary distillation. Accordingly, further processing of the stream comprising propane and dimethyl ether is required to refine the propane therefrom. [0003] Typically, in an oxygenate-to-olefins proces...

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Problems solved by technology

[0008] However, there is an azeotrope between propane and organic oxygen-containing compounds commonly used as extractive distillation solvents (such as methanol and propane, there is an azeotrope, at 1750KPa absolute pressure, the azeotrope temperature is 50.5 ° C, and the azeotrope contains 0.77% methanol wt%), therefore using the above two methods, although the dimethyl ether in the stream comprising propane and dimethyl ether can be removed, the propane product obtained at the top of the extractive distillation column still contains a relatively large amount of As an organic oxygen-containing compound for extraction and rectification solvents, propane products cannot be directly used as raw materials for propane dehydrogenation or light hydrocarbon cracking units, nor can they be directly used as liquefied petroleum gas

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