A kind of multi-reactor series process of ethylene oligomerization

Abstract

The invention discloses an ethylene oligomerization tanks-in-series technology. A reaction medium, a promoter, an iron-based catalyst and a polyethylene wax inhibitor are introduced into a first reactor for pre-reaction at a low temperature, and the reaction materials are introduced into a second reactor after activity starts to be reduced; reaction temperature is increased to maintain high reaction activity for a long time; the reaction materials are sequentially introduced into an n reactor, and the temperature of the reactor is kept high (Tn-Tn-1>=10 DEG C); gas-liquid-solid separation and analysis are conducted on a product after reaction ends. By the adoption of the ethylene oligomerization tanks-in-series technology, catalyst deactivation due to temperature runaway caused by high reaction activity in the early stage of reaction can be effectively avoided, high catalyst activity is maintained for a long time, the catalysis efficiency of the catalyst is improved, and the yield of liquid-phase alpha-olefin is increased remarkably. The reaction technology is good for safety and stable operation of devices so that high economic benefits can be obtained.

Description

technical field [0001] The invention designs the field of ethylene oligomerization to prepare high-grade linear α-olefins, and in particular relates to a multi-pot series process for increasing the activity of ethylene oligomerization and improving the catalytic efficiency of catalysts. Background technique [0002] Linear α-olefins usually refer to high-carbon linear terminal olefins above C4. They are an important organic chemical raw material that has developed rapidly in the past 30 years. They are widely used in synthetic lubricating oil base oils, comonomers, surfactants, and plasticizers. Agents, fungicides, emulsifiers and other chemical products. For example, 1-butene, 1-hexene and 1-octene are mainly used as polyethylene comonomers; 1-decene is the raw material for synthesizing high-grade lubricating oil base oil; C10-C14 α-olefins can be used to produce pour point depressing C14-C18 α-olefins can be used to produce α-olefin sulfonate AOS, which is the main compon...

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Problems solved by technology

U.S. Patent US2004 / 0111002 and Chinese Patent No. CN 1330612C all disclose the average concentration ratio of α-olefins along the length of the reactor in an improved plug-flow reactor using this type of iron-based catalyst than in a continuous stirred reactor Much lower, the formation of nonlinear α-olefins has less impurity content, which is conducive to the production of purer α-olefins; compared with unimproved plug flow reactors, this method can use lower ethylene pressure, thereby reducing Investment costs, but the pressure of the reaction in this method also needs to be kept above the bubble point of ethylene to ensure that all components (including ethylene) remain in the liquid phase, so that there is only a single liquid phase in the reactor, and the resulting α-olefin The product distribution range is narrow

[0006] It can be seen that there are still quite a lot of problems in the existing linear α-olefin preparation process, most of which have harsh reaction conditions, such as tending to operate under high temperature and high pressure conditions, the operation process is complicated, and there are high molecular weight polyethylene waxes in the reaction products. As well as impurities such as nonlinear α-olefins, the activity and catalytic efficiency of catalysts are also issues that need to be paid attention to in the industrial production of linear α-olefins

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