Liquid distributor for falling-film evaporator

Abstract

The invention provides a liquid distributor for a falling-film evaporator. The liquid distributor comprises heating tubes, a tube plate, a distribution disc, a dispersion disc, a seal head and a feed inlet pipe, wherein drainage tubes are inserted into the upper parts of the heating tubes; the lower parts of the drainage tubes are trumpet-shaped; the drainage tubes and the heating tubes are coaxial; gaps are formed between the outer walls of the drainage tubes and the inner walls of the heating tubes; the heating tubes on the tube plate are distributed in the form of a regular triangle; distribution disc holes in the distribution disc have diameters of 3 to 6 mm; and gaps are formed between the supporting plates for the drainage tube and the tube plate. Material liquid flows from distribution disc holes to tube plate and then enters the drainage tubes after overflowing; due to the buffering action of stored liquid among the drainage tubes, liquid distribution is allowed to be uniform, films formed by the material liquid on the walls of the heating tubes are uniform; and since the design of the distribution disc holes has smaller influence on material liquid distribution compared with common liquid distributor, the liquid distributor provided by the invention is simple.

Description

technical field [0001] The invention belongs to the field of evaporator design, in particular to a liquid distribution device for a falling film evaporator. Background technique [0002] Shell and tube falling film evaporator is usually used for the concentration of liquid, mainly composed of evaporation chamber, separation chamber, liquid distributor and other components. When evaporating, the liquid material is evenly sent to the inner wall of the evaporation chamber to heat the tube through the distributor, and the liquid material flows downward in the form of a film along the tube wall under the action of its own gravity, and evaporates at the same time. Falling film evaporator has the advantages of short material heating time, high efficiency, energy saving, not easy to scale, easy to clean, etc. It is widely used in chemical industry, light industry, food, medicine and other industrial industries. The function of the liquid distributor is to distribute the feed liquid...

AI Technical Summary

Problems solved by technology

[0004] 1. The thickness of the liquid film is unevenly distributed on the upper and lower sides of the tubes, and the film-forming effect of the material liquid on the heating tube wall is poor and even local dry walls appear

This unevenness is more obvious when the feed fluctuates, because the hole diameter of the distribution plate cannot be too small (too small is easy to block, and the equipment is not universal), and sometimes the feed liquid with low viscosity is interfered by the secondary steam of the feed liquid. For various reasons, even part of the splash will enter the heating tube

[0005] 2. In addition, ordinary liquid distributors often use more than 3 layers of distribution plates to solve the problem of material liquid impact and uneven distribution, and the structure is very complicated

And the design of the distribution hole of the ordinary liquid distributor has a great influence on the distribution of the liquid

However, it is often difficult to determine the number and diameter of the distribution holes in the actual design, and there are often large deviations.

[0006] 3. Due to the steam flow of the working medium, insufficient liquid volume, and different surface roughness of the tubes, the liquid flow between the tubes deviates from the vertical direction

The above problems will lead to partial drying of the surface of the evaporator tube during the working process of the falling film evaporator, and the liquid material is prone to drift in the vertical direction, especially in the tube bundle at the bottom of the evaporator, the flow rate of the liquid material is reduced, and it is easily affected by it. Partial drying phenomenon reduces evaporation efficiency and causes loss of effective heat transfer mass

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