Liquid vinyl chloride monomer dehydration system and dehydration process thereof

Abstract

The invention discloses a liquid vinyl chloride monomer dehydration system and a dehydration process thereof. The dehydration system includes a phase separator and an interface automatic control system connected to the phase separator. The phase separator comprises a cylinder, a material inlet end arranged on the upper side of one cylinder end, an inlet member connected to the material inlet end, a rectifier connected to the inlet member, a fiberfill section disposed behind the rectifier and connected to the rectifier, a baffle plate group section arranged behind the fiberfill section, a settling section arranged behind the baffle plate group section, a small cylinder disposed outside the cylinder bottom, and a light phase outlet arranged at the top of the cylinder. The dehydration system provided by the invention has the characteristics of simple structure, convenient use, and high working efficiency. And the phase separator employed by the dehydration process involved in the invention is static equipment, can realize efficient dehydration without any external force, the inside of the device adopts an efficient modular separation structure, the equipment size is effectively reduced, and at the same time sufficient residence time is satisfied. During vinyl chloride dehydration, the occurred self-aggregation phenomenon does not block the equipment, and long-term normal operation of the separation equipment can be ensured, thereby reducing the water phase content of liquid vinyl chloride monomer to a lowest level.

Description

technical field [0001] The invention relates to a dehydration system and a dehydration process thereof, in particular to a liquid-phase vinyl chloride monomer dehydration system and a dehydration process thereof. Background technique [0002] At present, in the production of polyvinyl chloride in the petrochemical field, in the production process of synthesizing polyvinyl chloride from vinyl chloride, the raw material of vinyl chloride must first remove water, and then remove impurities through rectification; the dehydration step is set because water can hydrolyze The peroxide generated by vinyl chloride and oxygen produces hydrogen chloride, formic acid, formaldehyde and other acidic substances, which corrodes steel equipment and produces Fe3+, which turns the color of the polymerized product yellow or produces black spot impurities. In the presence of hydrogen chloride and water, iron ions promote the oxidation process of vinyl chloride to produce more peroxides. This per...

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Problems solved by technology

But its disadvantages are equally obvious, for example: equipment operation cost is high, with a 100,000 tons / year polyvinyl chloride device, it needs to consume 100 tons of solid alkali every year, and cause a large amount of alkaline water discharge, at the same time, due to the fine NaOH powder Entrained in vinyl chloride, resulting in lower monomer polymerization quality and affecting production quality

[0006] CN 101289367A discloses a method and device for dehydrating vinyl chloride, which uses gravity sedimentation dehydration and liquid-liquid cyclone separation to achieve the purpose of dehydration. The process needs to provide two-level equipment, and the first-level equipment adopts gravity settling tanks. Unable to get rid of the traditional gravity sedimentation process, in order to increase the residence time to achieve a better dehydration effect, a larger separation tank is required, which requires a large investment in equipment, and the liquid-liquid cyclone separator needs to be increased and provided with sufficient centrifugal force to meet the dehydration requirements. Demand, so that enough energy needs to be provided to increase the energy consumption of the entire process

[0007] CN 200988828Y discloses a high-efficiency vinyl chloride dehydration device, which includes a horizontal shell, a pre-filter, a liquid-liquid coalescer, a foam and energy dissipator, and a water-repellent separator; The pre-filter removes solid impurities in the vinyl chloride medium, and the clean aqueous vinyl chloride enters the liquid-liquid coalescing filter element, and the small water droplets of the dispersed phase coalesce and grow up on the coalescing filter element. The knotted filter element settles to the bottom of the horizontal container by its own gravity. The defoaming energy dissipator can stabilize the flow state of the vinyl chloride medium in the horizontal container, and at the same time help the water droplets that have coalesced and grown up to settle and collect more effectively. The water droplets with small particle size that cannot grow up in time on the filter element flow to the outlet of the medium, and are intercepted by the water-repellent separator installed at the outlet of the medium; during the dehydration process of hydrous vinyl chloride, self-polymerization will occur, which will cause the coalescing filter element to be blocked. Equipment cleaning is difficult

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