Molecular sieve dehydration method for C-4 fraction

Abstract

The invention discloses a molecular sieve dehydration method for a C-4 fraction. The dehydration method comprises the following steps: adsorption; pressure relief and recovery; and regeneration. Molecular sieve dehydration columns (1), (2) and (3) are arranged; two molecular sieve dehydration columns are connected in series for adsorption and dehydration, and the rest molecular sieve dehydration column is used for pressure relief and recovery and regeneration; the molecular sieve dehydration columns are filled with 3A molecular sieves and 4A molecular sieves in grades; and when water content of a material flow at an outlet of a primary tandem molecular sieve dehydration column contacting with a raw material is greater than 5 [mu]g / g, the molecular sieve dehydration column is switched for pressure relief and recovery and regeneration, an original secondary molecular sieve dehydration column contacting with the raw material becomes a primary molecular sieve dehydration column contacting with the raw material, and the standby molecular sieve dehydration column becomes a secondary molecular sieve dehydration column contacting with the raw material. The molecular sieve dehydration method has the advantages of good dehydration effect, small material loss and low energy consumption.

Description

technical field [0001] The invention relates to refining hydrocarbon oil by solid adsorption in the absence of hydrogen, in particular to a method for dehydrating carbon four fraction molecular sieves. Background technique [0002] At present, in petrochemical or coal chemical enterprises, due to the factors of the upstream device process, such as the use of water to extract methanol to separate the C4 fraction in the MTBE device, the C4 fraction will carry water. After dehydration by the coalescer, the water content of the C4 fraction is 300~500μg / g. When the C4 fraction is used as a raw material for a downstream device, there is a relatively high requirement for its water content. For example, as a raw material for an alkylation unit or an olefin polymerization unit, the water content is required to be less than 5 μg / g. Therefore, if the water content of the C4 fraction is too high, it will It affects the operation of downstream devices or product quality, so the C4 fract...

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Problems solved by technology

[0008] For the dehydration of light hydrocarbon components by liquid-phase molecular sieve, inert gas such as nitrogen is often used as the regeneration medium. The consumption of nitrogen accounts for more than 70% of the energy consumption of the liquid-phase molecular sieve dehydration unit. A large amount of regeneration gas discharged into the hydrocarbon venting system of the factory will also cause damage to the factory. Negative Effects

[0009] "Modern Chemical Industry", 2003, 23(12), 38-40, Application C 4 + The liquid phase dehydration technology of mixed light hydrocarbons is used to transform the natural gas processing equipment. Three adsorption towers filled with 4A molecular sieves are used, two are connected in series, and one is used for dehydration. The C4 + The water content of mixed light hydrocarbons is less than 10×10 -6 Quality content, the background of this article is a natural gas company, using dry gas to regenerate 4A molecular sieve, but for petrochemical companies, the applicability is not strong

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