Process method and system for recycling ethylene glycol in industry for preparing ethylene glycol from coal

Abstract

The invention discloses a process method and a system for recycling ethylene glycol in the industry for preparing the ethylene glycol from coal. The process method is characterized in that a light component removal unit is provided with a plurality of light component removal towers, continuous coupling operation is carried out on the light component removal towers, tower-top steam of every two adjacent light component removal towers is used as a heat source for the corresponding next-effect light component removal tower and is communicated with a coupling reboiler of a next-effect dehydratingtower, and double-effect coupling can be formed by the tower-top steam and the coupling reboilers; a dehydrating unit is provided with a plurality of dehydrating towers, continuous coupling operationis carried out on the dehydrating towers, tower-top steam of every two adjacent dehydrating towers is used as a heat source for a next-effect light component removal refining tower and is communicatedwith a coupling reboiler of the corresponding next-effect dehydrating tower, and double-effect coupling can be formed by the tower-top steam and the coupling reboilers; a light component removal refining unit is provided with a single tower, and continuous operation is carried out on the single tower; a product refining unit is provided with a plurality of product refining towers, continuous coupling operation is carried out on the product refining towers, tower-top steam of every two adjacent product refining towers is used as a heat source for the corresponding next-effect product refiningtower and is communicated with a coupling reboiler of the next-effect product refining tower, and double-effect coupling can be formed by the tower-top steam and the coupling reboilers. The process method and the system have the advantages that light components, with the boiling points which are lower than the boiling point of water, in raw materials can be flexibly removed by the aid of the process method and the system, components with the boiling points which are higher than the boiling point of the water and are lower than the boiling point of the ethylene glycol also can be removed by theaid of the process method and the system, accordingly, the wastewater treatment pressure can be relieved, and indexes of ethylene glycol products can be improved.

Description

technical field [0001] The invention belongs to the technical field of coal-to-ethylene glycol recovery, and in particular relates to an ethylene glycol recovery process method and system used in the coal-to-ethylene glycol industry. Background technique [0002] Ethylene glycol is an important organic chemical raw material, about 90% of which is used in the polyester industry to produce polyester fibers, beverage bottles, films, etc. Other downstream products include antifreeze, refrigerants in the HVAC industry, etc. Synthesis gas to ethylene glycol, commonly known as "coal to ethylene glycol", is to use coal instead of petroleum ethylene to produce ethylene glycol. Compared with petroleum legal ethylene glycol, syngas to ethylene glycol has obvious resource advantages and cost advantages . Petroleum ethylene glycol is the main source of domestic supply, but the output is limited, and a large amount of ethylene glycol needs to be imported every year. [0003] The Chinese...

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Problems solved by technology

[0003] The Chinese patent with the publication number CN106748651A discloses a coal-to-ethylene glycol refining process and system, including a precision filter, a pre-stripping tower, a main stripping tower, a delightening tower, a degreasing tower, a product rectifying tower, a recovery tower, Heavy tower, liquid-phase hydrogenation reactor and de-alcoholization device, the process of refining crude ethylene glycol from coal through the process of precision filtration, dealcoholization, degreasing, product rectification, product recovery, hydrogenation, and ethylene glycol refining Obtain ethylene glycol product, although the present invention can carry out refining recovery to coal-based ethylene glycol, obtain high-quality product ethylene glycol, but this process method and system need consume a large amount of water vapor, the consumption of cooling water and power consumption Too many, cannot make full use of heat, and at the same time, the operation flexibility is poor, and it cannot be flexibly adjusted according to the process requirements

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