Improved technology and device for polyethylene device tail gas complete recycling
A polyethylene and tail gas technology, applied in the purification/separation of hydrocarbons, chemical instruments and methods, and dispersed particle filtration, etc., can solve the problems of hydrogen accumulation safety and hidden dangers, achieve good selective adsorption, avoid safety hazards, and simplify the process The effect of the process
Active Publication Date: 2015-12-23
SOUTHWEST RES & DESIGN INST OF CHEM IND
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Problems solved by technology
However, the nitrogen recovered by the above method in the prior art contains more hydrogen, that is, the recovered hydrogen-nitrogen mixed gas, if the recovered hydrogen-nitrogen mixed gas is directly returned to the degassing chamber for recycling, it may form The accumulation of hydrogen in the warehouse will cause serious safety hazards
Method used
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example 1
[0065] Exhaust gas of polyethylene plant in a factory is 1000Nm 3 / h, the pressure is 1.2MPa. After the tail gas passes through the high and low pressure cooling condensation recovery unit, coarse and fine filtration unit, and pre-purification unit, the gas composition shown in Table 2 is obtained:
[0066] Table 2 The composition of the tail gas of a polyethylene plant after condensation, filtration and pre-purification treatment (mol%)
[0067] component name
H 2
N 2
C 2 h 4
C 2 h 6
C 4 h 8
C 5 h 12
content
3.0
76.05
12.00
4.10
3.6
1.25
[0068] The gases shown in Table 2 are then processed using a pressure swing adsorption separation and concentration unit. The pressure swing adsorption separation device shown includes 6 adsorption towers, a set of buffer tanks and program control valves, etc. The adsorbents filled in the adsorption towers are respectively modified molecular sieve, modi...
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The invention discloses an improved technology and device for polyethylene device tail gas complete recycling. The improved technology includes the steps of: A. letting polyethylene device tail gas that passes through a high-low pressure cooling and condensation recovery unit, a coarse-fine filter unit and a pre-purification unit in order enter a pressure swing adsorption separation concentration unit, and performing separation to obtain a hydrocarbon component and hydrogen-nitrogen mixed gas; B. making the hydrogen-nitrogen mixed gas enter a dehydrogenation unit, conducting dehydrogenation treatment to obtain nitrogen with purity up to more than 98% and a hydrogen content of less than 1%. The improved device comprises the high-low pressure cooling and condensation recovery unit, the coarse-fine filter unit, the pre-purification unit, the pressure swing adsorption separation concentration unit and the dehydrogenation unit that are connected in order. The polyethylene device tail gas passes through the high-low pressure cooling and condensation recovery unit, the coarse-fine filter unit, the pre-purification unit, the pressure swing adsorption separation concentration unit and the dehydrogenation unit to be recovered, thereby obtaining the hydrocarbon component with purity up to more than 90% and nitrogen with purity up to more than 98% and a hydrogen content of less than 1%.
Description
technical field [0001] The invention relates to the technical field of tail gas recovery of polyethylene production equipment, more specifically, the invention relates to an improved process and device for completely recovering and reusing tail gas of polyethylene equipment. Background technique [0002] During the production of polyethylene, a large amount of hydrocarbons including unpolymerized ethylene and comonomers (propylene, butene, hexene, etc.) are usually discharged from the polymerization reactor and the polyethylene powder degassing bin. The typical composition of the tail gas of the polyethylene plant is shown in Table 1. This part of the polymerization tail gas is usually discharged to the flare pipe network, which causes a great waste of hydrocarbon resources and also pollutes the environment. The recovery of hydrocarbon components and nitrogen and other gases in polyethylene tail gas is of great significance to the energy saving and consumption reduction of ...
Claims
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Login to View More IPC IPC(8): B01D53/047B01D53/86B01D53/74B01D53/46B01D53/00B01D46/00C01B21/04C07C11/04C07C11/08C07C9/06C07C7/00C07C7/12
Inventor 刘丽张剑锋刘照利杨云
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND