Method and device for recovering polyethylene glycol raffinate byproduct from ethylene glycol process

A polyethylene glycol, recovery method technology, applied in chemical instruments and methods, separation/purification of hydroxyl compounds, water/sewage multi-stage treatment, etc., can solve problems such as recovery and utilization of polyethylene glycol residues that have not yet been seen , to shorten the residence time, improve the film forming effect and enhance the heat transfer effect

Inactive Publication Date: 2011-04-13
NINGBO POLYTECHNIC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, there is no literature related to the recycling of polyethylene glycol raffinate, a by-product of the ethylene glycol process.

Method used

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  • Method and device for recovering polyethylene glycol raffinate byproduct from ethylene glycol process
  • Method and device for recovering polyethylene glycol raffinate byproduct from ethylene glycol process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A recovery device for polyethylene glycol raffinate, a by-product of the ethylene glycol process, comprising: a preheater, a falling film evaporator, a dehydration rectification tower, an ethylene glycol separation tower, a diethylene glycol separation tower, a triethylene glycol Alcohol separation tower, intermediate tank, centrifuge, one end of the preheater 1 is connected to the falling film evaporator 2, and the top of the falling film evaporator 2 is sequentially connected to the dehydration rectification tower 3, the ethylene glycol separation tower 4, the diethylene glycol separation tower The glycol separation tower 5 and the triethylene glycol separation tower 6 are connected; the bottom of the falling film evaporator 2 is connected with the intermediate tank 7, the centrifuge 8, and the other end of the preheater 1 successively; the falling film evaporator 2 is a scraper type falling film evaporator.

[0037]Add 2% industrial-grade phosphoric acid (85%) to the...

Embodiment 2

[0040] Add 1% industrial-grade phosphoric acid (85%) to the raw material polyethylene glycol waste liquid, adjust the pH value to 9, transport it into the preheater 1 through a pump, preheat it to 200°C, and then transport it to the scraper type with an operating pressure of 30KPa Falling film evaporator 2, heavy components and salts are obtained from the bottom of the evaporator, and the heavy components are separated by a centrifuge 8 and circulated into the preheater 1; the polyol mixed liquid and water obtained from the top of the evaporator are sent to the dehydration distillation tower 3. The operating pressure of the dehydration distillation tower is 40KPa, the temperature at the top of the tower is 70°C, and the temperature at the bottom of the tower is 200°C. The ethylene glycol product is obtained at the top of the ethylene glycol separation tower 4 with an operating pressure of 40KPa, a tower top temperature of 175°C, and a bottom temperature of 220°C, and the mixed ...

Embodiment 3

[0043] Add 4% industrial-grade phosphoric acid (85%) to the raw material polyethylene glycol waste liquid, adjust the pH value to 7, transport it into the preheater 1 through a pump, preheat it to 220°C, and then transport it to the scraper type with an operating pressure of 40KPa Falling film evaporator 2, heavy components and salts are obtained from the bottom of the evaporator, and the heavy components are separated by a centrifuge and circulated into the preheater 1; the polyol mixed liquid and water obtained from the top of the evaporator are sent to the dehydration distillation tower 3. The operating pressure of the dehydration distillation tower is 30KPa, the temperature at the top of the tower is 65°C, and the temperature at the bottom of the tower is 200°C. The ethylene glycol product is obtained at the top of the ethylene glycol separation tower 4 with an operating pressure of 30KPa, a tower top temperature of 155°C, and a bottom temperature of 200°C, and the mixed al...

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PUM

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Abstract

The invention relates to a method and a device for recovering a polyethylene glycol raffinate byproduct form an ethylene glycol process. The method comprises the following steps of: (1) adding phosphoric acid into the polyethylene glycol raffinate, controlling the pH value to be between 7 and 9, conveying the mixture to a preheater (1), and preheating; (2) allowing a preheated material to enter a scraper falling-film evaporator (2), discharging a material at the bottom of the evaporator into an intermediate tank (3), and allowing the material to enter the preheater (1) through a centrifugal separator (8); (3) conveying the mixture of water and alcohol on the top of the falling-film evaporator to a dehydration rectifying tower (3); (4) conveying a mixed alcohol material at the bottom of the tower to an ethylene glycol separating tower (4); (5) conveying the material at the bottom of the tower to a diethylene glycol separating tower (5); and (6) conveying the material at the bottom to a triethylene glycol separating tower (6), and collecting products on the top and bottom of the tower respectively. The method is simple, efficient and low in energy consumption, and is suitable for industrial application; and by the method, the utilization rate of the raffinate produced by ethylene glycol is improved.

Description

technical field [0001] The invention belongs to the field of recovery methods and devices for polyethylene glycol raffinate, in particular to a recovery method and device for polyethylene glycol raffinate, a by-product of an ethylene glycol process. Background technique [0002] As an important chemical raw material, ethylene glycol is widely used in fields such as fibers, engineering plastics, and industrial refrigerants. The method of industrial preparation and production of ethylene glycol usually adopts the direct pressurized hydration method using ethylene oxide as the raw material. This method uses a pipeline reactor without using a catalyst, and the reaction is 150-2000 ° C, 0.8-2.0 MPa to prepare ethylene glycol. , the conversion rate of ethylene oxide is close to 100%, the selectivity of ethylene glycol is about 90%, and the main by-products are diethylene glycol and triethylene glycol. [0003] Due to the limitations of this process, in addition to components such...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C31/20C07C29/76C07C43/11C07C41/34C02F9/10
Inventor 孙向东李海涛刘世荣王斌
Owner NINGBO POLYTECHNIC
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