Pressure-change absorption separation method for ethylene and hydrogen from refining plant dry gas

Abstract

The invention relates to a method used to separate ethylene and hydrogen at the same time from the dry gas of an oil refinery, in particular to a method used to separate ethylene and hydrogen from the dry gas of an oil refinery through pressure swing adsorption. The method is carried out according to the following: the first step: elimination of carbon dioxide is completed; the second step: dehydration is completed; the third step: the extraction of ethylene is realized through pressure swing adsorption; and the fourth step: the recovery of hydrogen is finished through pressure swing adsorption. The method has the advantages that: both ethylene and hydrogen are separated from the dry gas of an oil refinery along with better separation effect, a simple flow and low energy consumption; the raw material adopted by the method has low price and adapts well to the raw gas of the dry gas of an oil refinery; valuable resource is obtained from waste gas and is used to further manufacture subsequent products with high added value; meanwhile, the method reduces atmospheric emission to protect the environment and has a long service life of equipment, low operating cost and lower cost; moreover, the method is especially suitable to make the raw material of a propionaldehyde production device which adopts water-soluble rhodium-phosphine complex compound as catalyst.

Description

1. Technical field [0001] The invention relates to a method for simultaneously separating ethylene and hydrogen from refinery dry gas, and is a method for separating ethylene and hydrogen from refinery dry gas by pressure swing adsorption. 2. Background technology [0002] The typical content of ethylene in the dry gas of the heavy catalysis plant is about 7% to 21% (volume). At present, the methods for recovering ethylene in the dry gas of the refinery include: cryogenic separation method, double metal salt complex absorption method, solvent Extraction method, expander method, etc., the details of each method are as follows: [0003] Cryogenic separation method: This method was jointly developed by Mobil Corporation of the United States and AirProducts Corporation, and was put into industrial production in 1987. By adopting the method, the yield of ethylene can reach 90% to 98%, the yield of ethane can reach 99%, and the yield of heavy hydrocarbon can reach 100%, and the i...

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Problems solved by technology

[0012] It can be seen from Table 1 that in the refinery dry gas recovery ethylene method, the cryogenic separation method and the intercooler oil absorption method are often used in industry, and the technology is relatively mature, but the investment and energy consumption are high, and the operating conditions are harsh

[0013] None of the above existing technologies can effectively realize the simultaneous separation of ethylene and hydrogen from refinery dry gas

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