Method for modeling and optimizing separation process of C8-aromatics simulated moving bed

A technology for simulating moving bed and optimization method, applied in the field of modeling and optimization of C8 aromatics simulated moving bed separation process, can solve problems that are not conducive to finding the optimal operating point, triangular theory ignores axial diffusion and mass transfer resistance, and cannot be very A good description of the separation process, etc.

CN104331636AInactive Publication Date: 2015-02-04EAST CHINA UNIV OF SCI & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-02-04
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a method for modeling and optimizing separation process of a C8-aromatics simulated moving bed. The method comprises the following steps that the constant pressure and temperature of the adsorption and separation process are considered, a liquid phase is assumed to be a dispersion piston flow, a solid phase is assumed to be a piston flow, a linear pushing force model is a mass transfer rate model, the adsorption balance is described by virtue of Langmuir isotherms, a C8-aromatics adsorption and separation process model is built, and multi-target operation problem of two typical simulated moving beds are optimized by a multi-target teaching optimization algorithm based on the model as follows: (a) the PX yield is maximized and the use amount of a desorption reagent is minimized; and (b) the PX yield and purity are maximized at the same time. The built model is capable of obtaining information of components of each bed layer of an adsorption and separation tower, the yield and the purity of main products in extraction and raffinate; with the combination of analysis of operation variables such as the flow of desorption reagent, the extraction liquid flow and the raffinate flow in the model by the optimization algorithm, the operation level of the simulated moving bed can be guided.
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Description

technical field

[0001] The invention relates to a modeling and optimization method for C8 aromatics simulated moving bed separation process, and the method can be used for simulation and operation optimization of simulated moving bed separation process. Background technique

[0002] Paraxylene (PX) is an important organic chemical raw material and a leading product in the polyester product chain. The separation of mixed xylenes is the most difficult link in the PX production process. The main industrial methods for separating mixed xylenes include cryogenic crystallization and adsorption separation, followed by complex extraction, eutectic and sulfonation methods, among which Molecular sieve adsorption separation technology based on continuous countercurrent simulated moving bed is currently the mainstream technology for producing p-xylene.

[0003] Simulated moving bed (SMB) separation technology is a continuous countercurrent chromatographic separation technology that eme...

Examples

Embodiment 1

[0068] Such as figure 1 Shown, the operation schematic diagram of the simulated moving bed of xylene, this embodiment comprises the following steps:

[0069] 1 Determine the parameters at a specific temperature and pressure according to the actual simulated moving bed device: including design parameters (column length, column diameter, number of plates, etc.) and operating parameters (flow rate, step time, etc.), and set adsorption equilibrium kinetics parameter initial value;

[0070] 2 Determine the simulated moving bed chromatography model

[0071] This embodiment adopts the TMB model method, which assumes that the pressure and temperature are constant, the liquid phase is a diffuse plug flow, the solid phase is a plug flow, the mass transfer rate model adopts a linear driving force model, and the adsorption equilibrium is described by a Langmuir isotherm. And without considering the dead volume of the transmission line on the pollution of the inlet and outlet pipelines, ...